DESCRIPTION
ELECTRIC POWER CONTROL APPARATUS, ELECTRIC POWER CONTROL
METHOD, AND ELECTRIC POWER FEEDING SYSTEM
5 TECHNICAL FIELD
[0001]
The present invention relates to an electric power
control apparatus, an electric power control method, and
an electric power feeding system for controlling supply
10 of electric power generated by a generating element.
BACKGROUND`: ART
[0002]
As an environment protection measure, development
15 of clean energy that does not emit carbon dioxide or
polluting substances is desired. Among others, solar
power generation and wind power generation have seen
increasingly widespread use in recent years.
[0003]
20 Particularly, use of solar power generating
elements in general households is gradually becoming
widespread due to the decrease in price and increase in
generation efficiency of solar batteries (solar panels)
that can be installed on rooftops of houses and the
25 like.
Solar power generating elements have also become
smaller in size, and sales of portable telephones
equipped with a solar battery have been available.
[0004]
30 A solar battery has characteristics different from
those of constant voltage sources, such as dry-cell
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batteries, and has characteristics as a current source
dependent on the voltage across its terminals.
Thus, in order to obtain a maximum output from a
solar battery, the voltage of a load connected to the
5 solar battery needs to be matched with the maximum
operating point voltage of the solar battery.
In the current-voltage characteristics of a solar
battery, there is only one maximum operating point (MPP:
Maximum Power Point) where the electric power is at the
10 maximum.
However, the current-voltage characteristics of a
solar battery vary depending on the environment such as
illuminance or temperature, so that the control for
obtaining the maximum operating point voltage needs to
15 be performed during operation of a device connected to
the solar battery.
Such a control for obtaining the maximum operating
point during operation of device is referred to as a
MPPT (Maximum Power Point Tracking) control.
20 [0005]
Many techniques for implementing the MPPT control
have been proposed, and those techniques for the directcurfent
path can be roughly categorized into the
following two types.
25 First type is a technique involving switching
between series and parallel connections of a plurality
of solar batteries (see Patent Document 1, for example).
Second type is a technique for obtaining the
maximum operating point by controlling a switching type
30 DC-DC converter (see Patent Document 2, for example).
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CITATION LIST
PATENT DOCUMENTS
[0006]
Patent Document 1: Japanese Patent Application Laid-Open
5 No. 2001-218365
Patent Document 2: Japanese Patent Application Laid--Open
No. 7-336910
SUMMARY OF THE INVENTION
10 PROBLEMS TO BE SOLVED BY THE INVENTION
[0007]
For implementing the MPPT control, according to
the first technique by which the connection of a
plurality of solar batteries is switched between series
15 and parallel connections, the control can be implemented
such that the maximum operating point can be approached.
However, in this technique, because the solar
batteries may be connected in parallel, the respective
solar batteries need to have the same maximum operating
20 point voltage.
Further, the possible modes of series or parallel
connection vary depending on the number of the solar
batteries. For example, when there are two solar
batteries, selection must be made from two maximum
25 operating points of an all-series connection and an allparallel
connection; when there are six solar batteries,
the selection must be made from four maximum operating
points.
In this case, there is the disadvantage that,
30 because the voltage differences between the respective
points are not uniform, a number of voltage sections
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exist in which the voltage across terminals cannot be
matched with the maximum operating point.
[0008]
According to the second technique for obtaining
5 the maximum operating point by controlling the DC-DC
converter, a control signal for a switch can be
controlled such that the charging current to a storage
battery can he at the maximum.
However, there is the disadvantage associated with
10 electric power loss in the DC-DC converter or electric
power loss in a control circuit such as a current
measurement circuit, for example.
[0009]
The present invention lies in providing an
15 electric power control apparatus, an electric power
control method, and an electric power feeding system by
which the maximum operating point of a generating
element, such as a solar battery, can be controlled to
be maintained, and by which electric power loss can be
20 avoided.
SOLUTIONS TO PROBLEMS
[0010]
An electric power control apparatus according to a
25 first aspect of the present invention includes an
electric power path switch unit configured to be
connectable with a plurality of generating elements, and
a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
30 supplied via the electric power path switch unit. The
electric power path switch unit includes a first
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connection switching function which switches between
series connection and parallel connection for the
plurality of generating elements, and a second
connection switching function which switches between
5 connected and non-connected for the generating elements
connected in series or in parallel connected to an input
side of the voltage conversion unit.
An electric power control method according to the
first aspect of present invention includes: when output
10 voltages of a plurality of generating elements are in a
first voltage range, connecting the plurality of
generating elements in parallel by a first connection
switching function, and performing connection switching
to a non-connected state by a second connection
15 switching function such that a voltage level of any of
the output voltages of the plurality of generating
elements is not converted by a voltage conversion unit;
when the output voltages of the generating elements are
in a second voltage range lower than the first voltage
20 range, connecting the plurality of generating elements
in parallel by the first connection switching function,
and performing connection switching to a connected state
by the second connection switching function such that
the voltage level of a final-stage output voltage of the
25 plurality of generating elements is converted by the
voltage conversion unit; and, when the output voltages
of the generating elements are in a third voltage range
lower than the second voltage range, connecting the
plurality of generating elements in series by the first
30 connection switching function, and performing connection
switching to the non-connected state by the second
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connection switching function such that the voltage
level of any of the output voltages of the plurality of
generating elements is not converted by the voltage
conversion unit.
5 [0011]
An electric power feeding system according to a
second aspect of the present invention includes a
plurality of generating elements configured to generate
electric power, and an electric power control apparatus
10 configured to supply the electric power from the
generating elements to a load side. The electric power
control apparatus includes an electric power path switch
unit configured to be connectable with the plurality of
generating elements, and a voltage conversion unit
15 configured to convert a voltage level generated by the
generating elements and supplied via the electric power
path switch unit. The electric power, path switch unit
includes a first connection switching function which
switches between series connection and parallel
20 connection for the plurality of generating elements, and
a second connection switching function which switches
between connected and non-connected for the generating
elements connected in series or in parallel to an input
side of the voltage conversion unit.
25 [0012]
An electric power control apparatus according to a
third aspect of the present invention includes an
electric power path switch unit configured to be
connectable with a plurality of generating elements and
30 including a function which switches between series
connection and parallel connection for the plurality of
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generating elements; a characteristics measurement
circuit configured to measure output characteristics of
the plurality of generating elements; and a control unit
configured to perform switching control of an electric
5 power path of the electric power path switch unit in
accordance with a measurement result from the
characteristics measurement circuit.
[0013]
An electric power feeding system according to a
10 fourth aspect of the present invention includes a
plurality of generating elements configured to generate
electric power, and an electric power control apparatus
configured to supply the electric power from the
generating elements to a load side. The electric power
15 control apparatus includes an electric power path switch
unit configured to be connectable with the plurality of
generating elements and including a function which
switches between series connection and parallel
connection, for the plurality of generating elements; a
20 characteristics measurement circuit configured to
measure output characteristics of the plurality of
generating elements; and a control unit configured to
perform switching control of an electric power path of
the electric power path switch unit in accordance with a
25 measurement result from the characteristics measurement
circuit.
[0014]
An electric power control apparatus according to a
fifth aspect of the present invention includes a voltage
30 conversion unit configured to convert a voltage level
generated by at least one generating element, a
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characteristics measurement circuit configured to
measure output characteristics of the generating
element, and a control unit configured to perform MPPT
control for tracking a maximum electric power operating
5 point of the generating element in the voltage
conversion unit in accordance with a measurement result
from the characteristics measurement circuit. The
voltage conversion unit is configured to compare a
variable reference voltage with the voltage level
10 generated by the generating element, and perform
charging or discharging such that the maximum electric
power operating point of the generating element is
tracked in accordance with a comparison result. The
control unit is configured to perform the MPPT control
15 for tracking the maximum electric power operating point
of the generating element in the voltage conversion unit
by supplying the variable reference voltage based on the
measurement result from the characteristics measurement
circuit.
20 [0015]
An electric power feeding system according to a
sixth aspect of the present invention includes at least
one generating element configured to generate electric
power, and an electric power control apparatus
25 configured to supply the electric power from the
generating element to a load side. The electric power
control apparatus includes a voltage conversion unit
configured to convert a voltage level generated by the
generating element; a characteristics measurement
30 circuit configured to measure output characteristics of
the generating element; and a control unit configured to
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perform MPPT control for tracking a maximum electric
power operating point of the generating element in the
voltage conversion unit in accordance with a measurement
result from the characteristics measurement circuit. The
5 voltage conversion unit is configured to compare a
variable reference voltage with the voltage level
generated by the generating element, and perform
charging or discharging such that the maximum electric
power operating point of the generating elements is
10 tracked in accordance with a comparison result. The
control unit is configured to perform the MPPT control
for tracking the maximum electric power operating point
of the generating element in the voltage conversion unit
by supplying the variable reference voltage based on the
15 measurement result from the characteristics measurement
circuit.
[0016]
An electric power control apparatus according to a
seventh aspect of the present invention includes an
20 electric power path switch unit configured to be
connectable with a plurality of generating elements and
including a function which switches between series
connection and parallel connection for the plurality of
generating elements, and a backflow prevention circuit
25 disposed in an electric power supply line for supplying
output electric power from the electric power path
switch unit to a load and including a function which
prevents backflow from a load side when a potential of
the load side is higher than a potential of the electric
30 power supply line.
[0017]
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An electric power feeding system according to an
eighth aspect of the present invention includes a
plurality of generating elements configured to generate
electric power , and an electric power control apparatus
5 configured to supply the electric power from the
generating elements to a load side . The electric power
control apparatus includes an electric power path switch
unit configured to be connectable with the plurality of
generating elements and including a function which
10 switches between series connection and parallel
connection for the plurality of generating elements, and
a backflow prevention circuit disposed in an electric
power supply line for supplying output electric power
from the electric power path switch unit to a load and
15 including a function which prevents backflow from the
load side when a potential of the load side is higher
than a potential of the electric power supply line.
[0018]
An electric power control apparatus according to a
20 ninth aspect of the present invention includes a
backflow prevention circuit including a function which
prevents backflow from a load side when a potential of a
load-side is higher than a potential of an electric
power supply line, a limit circuit configured to supply
25 electric power from a generating element to an
electricity storage element on a load side for charging
the electricity storage element, and be capable of
limiting the supplied electric power, the limit circuit
limiting the electric power supply such that a voltage
30 supplied to the electricity storage element is lower
than a full-charge voltage, and a control unit
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configured to terminate the backflow prevention function
of the backflow prevention circuit when the electric
power supply is limited by the limit circuit.
[0019]
5 An electric power feeding system according to a
tenth aspect of the present invention includes at least
one generating element configured to generate electric
power, and an electric power control apparatus
configured to supply the electric power from the
10 generating element to a load side. The electric power
control apparatus includes a backflow prevention circuit
including a function which prevents backflow from the
load side when a potential of the load side is higher
than a potential of an electric power supply line; a
15 limit circuit configured to supply the electric power
from the generating element to an electricity storage
element on the load side for charging the electricity
storage element, and be capable of limiting the supplied
electric power, the limit circuit limiting the electric
20 power supply such that a supply voltage to the
electricity storage element is lower than a full-charge
voltage; and a control unit configured to terminate the
back-flow prevention function of the backflow prevention
circuit when the electric power supply is limited by the
25 limit circuit.
[0020]
An electric power control apparatus according to
an eleventh aspect of the present invention includes an
electric power path switch unit configured to be
30 connectable with a plurality of generating elements and
including a function which switches between series
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connection and parallel connection for the plurality of
generating elements, and a limit circuit configured to
supply electric power from the generating elements to an
electricity storage element on a load side for charging
5 the electricity storage element, and be capable of
limiting the supplied electric power. The limit circuit
is configured to limit the electric power supply such
that a supply voltage to the electricity storage element
is lower than a full-charge voltage.
10 [0021]
An electric power feeding system according to a
twelfth aspect of the present invention includes a
plurality of generating elements configured to generate
electric power, and an electric power control apparatus
15 configured to supply the electric power from the
generating elements to a load side. The electric power
control apparatus includes an electric power path switch
unit configured to be connectable with the plurality of
generating elements and including a function which
20 switches between series connection and parallel
connection for the plurality of generating elements, and
a limit circuit configured to supply the electric power
from- the generating elements to an electricity storage
element on the load side for charging the electricity
25 storage element, and be capable of limiting a supply
voltage. The limit circuit is configured to limit
voltage supply such that the supply voltage to the
electricity storage element is lower than a full-charge
voltage.
30 [0022]
An electric power control apparatus according to a
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thirteenth aspect of the present invention includes an
electric power path switch unit configured to be
connectable with a plurality of generating elements and
including a function which switches between series
5 connection and parallel connection for the plurality of
generating elements; a voltage conversion unit
configured to convert a voltage level generated by the
generating elements and supplied via the electric power
path switch unit; and a control unit configured to
10 perform charging control by supplying electric power
from the generating elements to an electricity storage
element on a load side by performing switching control
of the electric power path switch unit. The control unit
is configured to perform switching such that, when a
15 voltage of the electricity storage element is equal to
or less than a certain voltage, the electric power is
directly supplied from the generating elements to the
electricity storage element, and when the voltage of the
electricity storage element is equal to or more than the
20 certain voltage, operating voltages for the electric
power path switch unit, the voltage conversion unit, and
the control unit can be obtained from the electricity
storage element.
[0023]
25 An electric power feeding system according to a
fourteenth aspect of the present invention includes a
plurality of generating elements configured to generate
electric power, and an electric power control apparatus
configured to supply the electric power from the
30 generating elements to a load side. The electric power
control apparatus includes an electric power path switch
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unit configured to be connectable with the plurality of
generating elements and including a function which
switches between series connection and parallel
connection for the plurality of generating elements; a
5 voltage conversion unit configured to convert a voltage
level generated by the generating elements and supplied
via the electric power path switch unit; and a control
unit configured to perform charging control by supplying
the electric power from the generating elements to the
10 load side by performing switching control of the
electric power path switch unit. The control unit is
configured to compare an input voltage due to the
generating elements with a charging voltage of the load
and perform initial charging by supplying the voltage
15 due to the generating elements to the load side when the
input voltage is higher. When the charging voltage
becomes higher than the input voltage as a result of the
initial charging, the control unit switches operating
voltages for the electric power path switch unit, the
20 voltage conversion unit, and the control unit from the
voltage due to the generating elements to the charging
voltage on the load side.
[0024]
An electric power control apparatus according to a
25 fifteenth aspect of the present invention includes an
electric power path unit configured to be connectable
with a plurality of generating elements with different
rates of change of a voltage with respect to illuminance
or temperature, and a voltage conversion unit configured
30 to convert a voltage level generated by the generating
elements and supplied via the electric power path unit.
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The electric power path unit is configured to connect
the generating elements with a large rate of change of
the voltage to the voltage conversion unit, and put the
generating elements with a small rate of change of the
5 voltage to a non-connected state with respect to the
voltage conversion unit.
[0025]
An electric power feeding system according to a
sixteenth aspect of the present invention includes a
10 plurality of generating elements with different rates of
change of a voltage with respect to illuminance or
temperature, and an electric power control apparatus
configured to supply electric power from the generating
elements to a load side. The electric power control
15 apparatus includes an electric power path unit
configured to be connectable with the plurality of
generating elements with the different rates of change
of the voltage with respect to illuminance or
temperature, and a voltage conversion unit configured to
20 convert a voltage level generated by the generating
elements and supplied via the electric power path unit.
The electric power path unit is configured to connect
the--generating elements with a large rate of change of
the voltage to the voltage conversion unit, and put the
25 generating elements with a small rate of change of the
voltage in a non-connected state with respect to the
voltage conversion unit.
EFFECTS OF THE INVENTION
30 [0026]
According to the present invention, the maximum
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operating point of a generating element such as a solar
.battery can be controlled to be maintained, and electric
power loss can be avoided.
5 BRIEF DESCRIPTION OF DRAWINGS
[0027]
Fig. 1 is a diagram showing an example of an
overall configuration of an electric power feeding
system according to an embodiment of the present
10 invention;
Fig. 2 is a diagram showing an equivalent circuit
of a solar power generation panel as a generating
element according to the present embodiment.
Fig. 3 is a diagram showing current-voltage
15 characteristics of a general solar battery.
Fig. 4 is a diagram showing a configuration
example of an electricity storage element according to
the present embodiment.
Fig. 5 is a diagram showing a configuration
20 example of a power switch circuit according to the
present embodiment.
Fig. 6 is a first figure of examples of patterns
of electric power paths formed by the power switch
circuit of Fig. 5.
25 Fig. 7 is a second figure of examples of patterns
of the electric power paths formed by the power switch
circuit of Fig. 5.
Fig. 8 shows a truth table of gate voltages of
switches for controlling the electric power path of the
30 power switch circuit according to the present
embodiment.
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Fig. 9 is a diagram showing the flow of electric
power through an electric power path PTA selectively
formed by the power switch circuit according to the
present embodiment.
5 Fig. 10 is a diagram showing the flow of electric
power through an electric power path PTB selectively
formed by the power switch circuit according to the
present embodiment.
Fig. 11 is a diagram showing the flow of electric
10 power through an electric power path PTC selectively
formed by the power switch circuit according to the
present embodiment.
Fig. 12 is a diagram showing the flow of electric
power through an electric power path PTD selectively
15 formed by the power switch circuit according to the
present embodiment.
Fig. 13 is a diagram showing the flow of electric
power through an electric power path PTE selectively
formed by the power switch circuit according to the
20 present embodiment.
Fig. 14 is a diagram showing the flow of electric
power through an electric power path PTF selectively
formed by the power switch circuit according to the
present embodiment.
25 Fig. 15 is a diagram showing the flow of electric
power through an electric power path PTG selectively
formed by the power switch circuit according to the
present embodiment.
Fig. 16 is a diagram showing the flow of electric
30 power through an electric power path PTH selectively
formed by the power switch circuit according to the
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present embodiment.
Fig. 17 is a diagram showing the flow of electric
power through an electric power path PTI selectively
formed by the power switch circuit according to the
5 present embodiment.
Fig. 18 is a diagram showing the flow of electric
power through an electric power path PTJ selectively
formed by the power switch circuit according to the
present embodiment.
10 Fig. 19 is a diagram showing the flow of electric
power through an electric power path PTK selectively
formed by the power switch circuit according to the
present embodiment.
Fig. 20 is a diagram showing the flow of electric
15 power through an electric power path PTL selectively
formed by the power switch circuit according to the
present embodiment.
Fig. 21 illustrates that the maximum electric
power can be obtained from the generating elements
20 (solar batteries) by selecting one of the electric power
paths regardless of illuminance or temperature.
Fig. 22 is a diagram showing electric power paths
and electric power efficiency on an illuminance basis.
Fig. 23 is a diagram showing a first function
25 example of a characteristics measurement circuit
according to the present embodiment.
Fig. 24 is a diagram showing a second function
example of the characteristics measurement circuit
according to the present embodiment.
30 Fig. 25 is a diagram showing electric power paths
selected by operation state determination on the basis
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of an open voltage Vop when two generating elements are
performing a generating operation with virtually no
shades.
Fig. 26 is a diagram showing a process where the
5 two generating elements are performing a generating
operation although with shades.
Fig. 27 is a diagram showing electric power paths
selected by the operation state determination on the
basis of the open voltage Vop when the two generating
10 elements have different generating operation states.
Fig. 28 is a diagram showing electric power paths
selected by the operation state determination on the
basis of the open voltage Vop when one of the two
generating elements is not in a generating operation
15 state but the other is in a generating operation state.
Fig. 29 is a diagram showing electric power paths
selected by the operation state determination by the
open voltage Vop when only one of the two generating
elements is connected.
20 Fig. 30 is a state transition diagram illustrating
a determination as to whether the generating elements
are in a generating operation state.
Fig. 31 is a state transition diagram illustrating
a determination as to which electric power paths are in
25 operation when the two generating elements in state Si
are both in a generating operation state.
Fig. 32 is a state transition diagram illustrating
a determination as to which electric power paths are in
operation when one generating element (SC1) in state S2
30 is in a generating operation state.
Fig. 33 is a state transition diagram illustrating
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a determination as to which electric power paths are in
operation when one generating element (SC2) in state S3
is in a generating operation state.
Fig. 34 is a flowchart illustrating in a
5 simplified manner a process of selecting the electric
power path from a result of measuring a short-circuit
current and an open voltage.
Fig. 35 is a first flowchart concretely
illustrating the process selecting the electric power
10 path from the result of measuring the short-circuit
current and the open voltage.
Fig. 36 is a second flowchart concretely
illustrating the process of selecting the electric power
path from the result of measuring the short-circuit
15 current and the open voltage.
Fig. 37 is a third flowchart concretely
illustrating the process of selecting the electric power
path from the result of measuring the short-circuit
20
current and the open voltage.
Fig. 38 is a fourth flowchart concretely
illustrating the process of selecting the electric power
path from the result of measuring the short-circuit
current and the open voltage.
Fig. 39 is a circuit diagram of a first
25 configuration example of a characteristics measurement
circuit according to the present embodiment.
Fig. 40 is a diagram showing I-V characteristics
obtained by simulation by diverting a capacitor in a
step-up circuit in the characteristics measurement
30 circuit according to the present embodiment.
Fig. 41 is a circuit diagram of a second
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configuration example of the characteristics measurement
circuit. according to the present embodiment.
Fig. 42 is a circuit diagram of a third
configuration example of the characteristics measurement
5 circuit according to the present embodiment.
Fig. 43 is a circuit diagram of a fourth
configuration example of the characteristics measurement
circuit according to the present embodiment.
Fig. 44 is a circuit diagram of a concrete
10 configuration example of a transmission gate of the
characteristics measurement circuit of Fig. 43.
Fig. 45 is a diagram showing a simulation result
obtained by the characteristics measurement circuit of
Fig. 43.
15 Fig. 46 is a circuit diagram of a basic
configuration example of a step-up type switching
regulator as a voltage conversion unit according to the
present embodiment.
Fig. 47 is a diagram illustrating a basic
20 operation of the step-up type switching regulator.
Fig. 48 is a diagram illustrating an operation of
the step-up type switching regulator of Fig. 46.
Fig. 49 is a circuit diagram of a configuration
example of a step-up type switching regulator with a
25 detection system for detecting a change in the operation
frequency of a PFM control unit of Fig. 46.
Fig. 50 is a diagram illustrating variations of
the I-V characteristics of the generating elements
(solar batteries) depending on temperature changes.
30 Fig. 51 is a circuit diagram of a basic
configuration example of a step-down-type switching
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regulator as a voltage conversion unit according to the
present embodiment.
Fig. 52 is a circuit diagram of a configuration
example of a backflow prevention circuit according to
5 the present embodiment.
Fig. 53 is a circuit diagram of a configuration
example of a current/voltage limit circuit according to
the present embodiment.
Fig. 54 is a flowchart illustrating an overall
10 charging control by an electric power control apparatus
according to the present embodiment.
Fig. '°55 shows an example in which the
current/voltage limiting circuit according to the
present embodiment is disposed not just in an output
15 stage but also in an input stage of the electric power
control apparatus.
Fig. 56 is a diagram illustrating different rates
of change of voltage (open voltage or:maximum operating
point voltage) with respect to illuminance depending on
20 the type of solar battery.
Fig. 57 is a diagram illustrating a mode of
connection in a case where different types of solar
batteries are used.
25 MODE FOR CARRYING OUT THE INVENTION
[0028]
In the following, an embodiment of the present
invention will be described with reference to the
drawings.
30 1. Overall configuration of electric power feeding
system
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2. Configuration example of generating element
3. Configuration example of electricity storage element
4. Configuration example of electric power control
apparatus
5 4-1. Configuration example of power switch circuit
(electric power path switch unit)
4-2. Configuration example of characteristics
measurement circuit and control of electric power path
based on result of characteristics measurement
10 4-3. Concrete configuration example of characteristics
measurement circuit
4-4. Concrete configuration example of voltage
conversion unit
4-5. Configuration example of backflow prevention
15 circuit
4-6. Charging control
4-7. Overall charging control
5. Case where different types of solar battery are used
[0029]
20 <1. Overall configuration of electric power feeding
system>
Fig. 1 shows an example of an overall
configuration of an electric power feeding system
according to an embodiment of the present invention.
25 [0030]
The electric power feeding system 10 includes a
plurality of generating elements 20-n (n = 2 in the
present embodiment), an electric power control apparatus
30, and an electricity storage element 40 as major
30 constituent elements.
The electric power feeding system 10 also includes
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a thermistor 50 connected to the electric power control
apparatus 30.
[0031]
The electric power feeding system 10 is configured
5 to charge (store electricity in) the electricity storage
element (battery) 40, which is a secondary battery, from
the generating elements 20-1 (SCI) and 20-1 (SC2), such
as solar batteries, not just under sun light but also
under other everyday environments, such as in the shade,
10 under indirect light, or inside a bright room.
Particularly, the electric power control apparatus
30 is formed as a charging control LSI for fully
utilizing the electric power generated by the generating
elements 20.
15 [0032]
The electric power control apparatus 30 may be
connected with a Li+ type (including polymer) secondary
battery as the electricity storage element 40 and charge
the secondary battery.
20 To the electric power control apparatus 30, one or
a plurality of generating elements may be connected.
According to the present embodiment, one or two
generating elements 20-1 and 20-2 may be connected.
According to the present embodiment, the electric
25 power control apparatus 30 may utilize an arbitrary
number of cells connected in series, including a single
cell.
The electric power control apparatus 30 may
perform connection switching control concerning the mode
30 of connection of the plurality of generating elements,
such as whether the generating elements are to be
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connected in series or in parallel, depending on the
output voltage value of the generating elements. The
electric power control apparatus 30 may also perform
switching control as to whether a voltage is to be
5 stepped up or down by inputting the voltage to a voltage
conversion unit such as a DC-DC converter.
[0033]
The electric power control apparatus 30 may
utilize various types of the generating elements 20 and
10 is configured to exert control such that the maximum
efficiency can be obtained regardless of the electric
power-voltage characteristics of the generating elements
20.
The electric power control apparatus 30 may be
15 charged with high efficiency by performing MPPT control
whereby the maximum electric power operating point of
the generating elements (solar batteries) 20 is tracked.
The electric power control apparatus 30 may perform the
MPPT control even when the generating elements 20
20 include a single cell.
[0034]
The electric power control apparatus 30 may
control the start and end (full charge) of charging of
the electricity storage element 40.
25 The electric power control apparatus 30 includes
the function which terminates charging when a fixed or
variable charging end voltage is reached, for example.
The electric power control apparatus 30 includes
the function which starts charging when a fixed or
30 variable charging start voltage is reached after
charging is terminated, for example.
25
SP262791W000
[0035]
The electric power control apparatus 30 may
control the maximum charging current at the time of high
illuminance, for example, by using an external current
5 control resistor. A current control threshold value in
this case may be set by providing an external resistor
for measuring the charging current that flows through
the electricity storage element 40.
[0036]
10 The,electric power control apparatus 30 includes
the function which decreases a loss of a forwarddirection
voltage VF while preventing backflow from the
electricity storage element 40 to the generating
elements 20 by a biopass control of a backflow
15 prevention diode.
The electric power control apparatus 30 includes
the function which decreases a loss due to difference in
illuminance between the two generating elements 20-1 and
20-2, together with the prevention of backflow between
20 the generating elements 20-1 and 20-2.
The electric power control apparatus 30 includes
the function which outputs electric power from the
generating elements 20 via load drive terminals after
full charge detection detecting an open voltage of the
25 electricity storage element 40 having reached a certain
value.
The electric power control apparatus 30 may
perform initial charging when the electricity storage
element 40 is in an over-discharged state with its
30 voltage not more than a predetermined voltage, such as
not more than 2.7 V, until the voltage recovers. In this
26
SP262791W000
case, the electric power control apparatus 30 may be
charged by decreasing (limiting) current by using an
external current limit resistor.
The electric power control apparatus 30 includes
5 the function which prevents charging at temperatures of
0°C or lower or 60°C or higher by using an externally
connected thermistor, for example.
The electric power control apparatus 30 may
control termination of charging and transition of
10 charging to a sleep mode by using an external enable
terminal, for example.
The electric power control apparatus 30 may be
configured to output output electric power information.
[0037]
15 In the following, concrete configurations and
functions of various components will be described by way
of example.
In the following, after the configuration and
function of the generating elements 20 and the
20 electricity storage element 40 are described, a concrete
configuration and function of the electric power control
apparatus 30 will be described.
[0038]
<2. Configuration example of generating element>
25 The generating elements 20-1 and 20-2 have the
function which generates electricity by using natural
energy, such as sunlight or wind power, and supplies the
generated electric power to the electric power control
apparatus 30.
30 According to the present embodiment, as the
generating elements 20-1 and 20-2, solar power
27
SP262791W000
generation panels that utilize photoelectric conversion
of s.unlight, such as solar potential, are adopted.
[0039]
Fig. 2 shows an equivalent circuit of a solar
5 power generation panel as the generating elements
according to the present embodiment.
[0040]
The solar power generation panel (solar battery)
21, as shown in the equivalent circuit of Fig. 2,
10 produces a current on the basis of light input.
In Fig. 2, the light input OPT is substituted by
electromotive force (Iph) to indicate current Ish.
Further, in Fig. 2, a sum of resistance of a
substrate, a light receiving layer, and an electrode
15 portion of the solar battery 21 is indicated by series
resistance Rs, and the loss resistance of the solar
battery 21 is indicated by Rsh.
In Fig. 2, an output current of.the solar battery
21 is indicated by Id, and an output voltage of the
20 solar battery 21 is indicated by V.
The solar battery 21 produces more current as the
amount of incident light increases and less current when
it is darker. In the equivalent circuit of Fig. 2, the
brightness of light is indicated by the magnitude of the
25 current source. As the voltage increases, the current
gradually decreases.
[0041]
The equivalent circuit has the configuration such
that a current source 22, a diode 23, and a resistor 24
30 are connected in parallel, and a resistor 25 is
connected in series.
28
SP262791W000
The current source 22 supplies an optical current
Iph, and the diode 123 is an ideal diode. When the
voltage V across the terminals of the solar battery 21
is increased, the current Iph from the current source 22
5 flows through the diode 23, so that the current I that
flows on the terminal side decreases as the voltage V
increases.
[0042]
Fig. 3 shows the current-voltage characteristics
10 of a general solar battery.
The output current value of the solar battery 21
is uniquely determined when the voltage value across the
terminals is determined.
The voltage across the terminals when the current
15 value is zero is referred to as an open voltage (Voc),
while the output current value when the voltage value
across the terminals is zero is referred to as a shortcircuit
current (Isc).
As described above, in the current-voltage
20 characteristics curve of the solar battery, there is
only one maximum operating point where the electric
power (= voltage x voltage) is at the maximum.
_. The current at the maximum operating point is
referred to as a maximum operating point current (Ipm).
25 The voltage at the maximum operating point is referred
to as a maximum operating point voltage (Vpm).
[0043]
Because of such characteristics of the solar
battery, in order to obtain the maximum output from the
30 solar battery, the voltage of a load connected to the
solar battery needs to be matched with the maximum
29
SP262791W000
operating point voltage of the solar battery.
Because the current-voltage characteristics of the
solar battery vary depending on the environment, such as
illuminance or temperature, the control for obtaining
5 the maximum operating point voltage needs to be
performed during operation of the device connected to
the solar battery.
According to the present embodiment, various
controls are performed in the electric power control
10 apparatus 30, f_or example, a control concerning the mode
of connection of a plurality of the generating elements
20-1 and 2G-2, i.e., whether they are connected in
series or parallel, depending on the output voltage
values of the generating elements, and a switching
15 control for determining whether a voltage is to be
stepped up or down by inputting the voltage to a voltage
conversion unit such as a DC-DC converter.
[004]
The electric power obtained by the solar battery
20 21 is a direct current, and the direct-current electric
power (DC electric power) is supplied to the electric
power control apparatus 30.
[0045]
<3. Configuration example of electricity storage
25 element>
The electricity storage element 40 stores the
electric power supplied from the electric power control
apparatus 30.
The electricity storage element 40 may be of a
30 type with a charging voltage variable, such as an
electric double layer capacitor or a lithium-ion type
30
S2262791W000
secondary battery.
[0046]
Fig. 4 shows a configuration example of the
electricity storage element according to the present
5 embodiment.
[0047]
The electricity storage element 40 shown in Fig. 4
includes an assembled battery 41, a charging control
field effect transistor (FET) 42, a discharging control
10 FET 43, a diode 44, and a current detecting resistor 45.
The electricity storage element 40 has a positive
electrode terminal Tl and a negative electrode terminal
T2 connected to a positive electrode terminal and a
negative electrode terminal, respectively, of an
15 electronic device as a load.
In the electricity storage element 40, under the
control of the electric power control apparatus 30, the
assembled battery 41 is charged or discharged via the
charging control FET 42, the discharging control FET 43,
20 the diode 445, and the current detecting resistor 45.
[0048]
The assembled battery 41 is a secondary battery
such-as a lithium-ion secondary battery, and includes a
plurality of battery cells connected in series and/or
25 parallel.
In the example of Fig. 4, three battery cells are
connected in series.
According to the present embodiment, the electric
power control apparatus 30 performs a control for
30 preventing over-charging or over-discharging of the
electricity storage element 40, and a control for
SP262791W000
has reached the predetermined voltage, charging is
conducted with a constant voltage (CV charging).
Charging ends when the charging current converges to
substantially zero [A].
5 [0051]
<4. Configuration example of electric power control
apparatus>
As shown in Fig. 1, the electric power control
apparatus 30 includes a voltage conversion unit 31 and a
10 power switch circuit 32 as an electric power path switch
unit included in an electric power path unit.
The electric power control apparatus 30 includes a
characteristics measurement circuit 33, a first control
unit 34, a second control unit 35, a backflow prevention
15 circuit 36, a current/voltage limit circuit 37, and a
start-up circuit 38 as major constituent elements.
[0052]
The voltage conversion unit 31 includes the
function which steps up or down voltages generated by
20 the generating elements 20-1 and 20-2 and selectively
supplied by the power switch circuit 32.
The voltage conversion unit 31 supplies a voltage
obtained by stepping up or down to the electricity
storage element 40 via the power switch circuit 32 and
25 the backflow prevention circuit 36, for example.
The voltage conversion unit 31 is constructed of a
DC-DC converter, for example.
A concrete configuration of the voltage conversion
unit 31 will be described in detail later.
30 [0053]
<4-1, Configuration example of power switch
33
SP262791W000
circuit>
The power switch circuit 32 includes the function
which determines the connection relationship among the
two generating elements (solar batteries) 20-1 and 20-2,
5 the voltage conversion unit (step-up/down circuit) 31,
and the electricity storage element (secondary battery)
40 in accordance with control exerted by the first
control unit 34 or the second control unit 35.
The power switch circuit 32 is configured to be
10 capable of performing electric power path switching
control depending on an output state of the generating
elements 20'-1 and 20-2.
Specifically, the power switch circuit 32
functions as an electric power path switch unit.
15 [0054]
The power switch circuit 32 according to the
present embodiment includes a first connection switching
function which switches between series connection and
parallel connection for the two generating elements 20-1
20 and 20-2 in accordance with the control by the first
control unit 34 or the second control unit 35.
The power switch circuit 32 further includes a
second connection switching function which switches the
generating elements 20-1 and 20-2 connected to the input
25 side of the voltage conversion unit 31.
The power switch circuit 32 according to the
present embodiment is basically configured to be capable
of performing at least the following connection
switching by the first connection switching function and
30 the second connection switching function.
[0055]
34
SP262791WO00
[Switching control for series; parallel and stepup;
parallel; series and step-up; and parallel and stepdown]
The power switch circuit 32 connects the
5 generating elements 20-1 and 20-2 in series and outputs
an output voltage from the generating elements 20-1 and
20-2 as is without inputting it to the voltage
conversion unit 31.
Alternatively, the power switch circuit 32
10 connects the generating elements 20-1 and 20-2 in
parallel or in series and inputs an output voltage to
the voltage conversion unit 31 so that the voltage can
be stepped-up or stepped-down for output.
Alternatively, the generating elements 20-1 and
15 20-2 are connected in parallel and an output voltage is
output as is without inputting it to the voltage
conversion unit 31.
[0056]
(Parallel)
20 When the output voltages of the generating
elements 20-1 and 20-2 are in a first voltage range V1,
the power switch circuit 32 connects the generating
elements 20-1 and 20-2 in parallel by the first
connection switching function.
25 In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is not input to the voltage conversion
unit 31 by the second connection switching function so
as to prevent conversion of the voltage level of either
30 of the output voltages of the generating elements 20-1
and 20-2 by the voltage conversion unit 31.
35
SP262791W000
[0057]
(Parallel and step-up)
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in parallel by the
5 first connection switching function when the output
voltages of the generating elements 20-1 and 20-2 are in
a second voltage range V2 (< Vl).
In this case, the power switch circuit 32 performs
the connection switching such that the generated
10 electric power is input to the voltage conversion unit
31 by the second connection switching function so as to
allow the voltage level of a final-stage output voltage
of the generating elements 20-1 and 20-2 to be converted
by the voltage conversion unit 31.
15 [0058]
(Series)
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 inseries by the first
connection switching function when the output voltages
20 of the generating elements 20-1 and 20-2 are in a third
voltage range V3 (< V2 < V1).
In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is not input to the voltage conversion
25 unit 31 by the second connection switching function so
as to prevent conversion of the voltage level of either
of the output voltages of the generating elements 20-1
and 20-2 by the voltage conversion unit 31.
[0059]
30 (Series and step-up)
The power switch circuit 32 connects the
36
SP262791W000
generating elements 20-1 and 20-2 in series by the first
connection switching function when the output voltages
of the generating elements 20-1 and 20-2 are in a fourth
voltage range V4 (< V3 < V2 < V1).
5 In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is input to the voltage conversion unit
31 by the second connection switching function so as to
allow the voltage level of the final-stage output
10 voltage of the generating elements 20-1 and 20-2 to be
converted by the voltage conversion unit 31.
[0060]
(Parallel and step-down)
The power switch circuit 32 connects the
15 generating elements 20-1 and 20-2 in parallel by the
first connection switching function when the output
voltages of the generating elements 20-1 and 20-2 are in
a fifth voltage range V5 (> Vi > V2 > V3 > V4).
In this case, the power switch circuit 32 performs
20 the connection switching such that the generated
electric power is input to the voltage conversion unit
31 by the second connection switching function so as to
allow the voltage level of the final-stage output
voltage of the generating elements 20-1 and 20-2 to be
25 converted by the voltage conversion unit 31.
[0061]
In the above switching controls, the following
relationship holds: [(output voltage of generating
elements in the case of series and step-up) < (output
30 voltage in the case of series) < (output voltage in the
case of parallel and step-up) < (output voltage in the
37
SP262791W000
case of parallel) < (output voltage in the case of
parallel and step-down)].
[0062]
[Switching control for series; series and step-
5 down; parallel; series and step-up; and parallel and
step-down]
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in series and outputs
an output voltage as is without inputting it to the
10 voltage conversion unit 31.
Alternatively, the power switch circuit 32
connects the generating elements 20-1 and 20-2 in series
or in parallel and inputs an output voltage to the
voltage conversion unit 31 so that the voltage can be
15 stepped-down or stepped-up for output.
Alternatively, the generating elements 20-1 and
20-2 are connected in parallel and an output voltage is
output as is without inputting it to, the voltage
conversion unit 31.
20 [0063]
(Parallel)
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in parallel by the
first connection switching function when the output
25 voltages of the generating elements 20-1 and 20-2 are in
a sixth voltage range V6.
In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is not input to the voltage conversion
30 unit 31 by the second connection switching function so
as to prevent conversion of the voltage level of either
38
SP262791W000
of the output voltages of the generating elements 20-1
and 20-2 by the voltage conversion unit 31.
[0064]
(Series and step-down)
5 The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in series by the first
connection switching function when the output voltages
of the generating elements 20-1 and 20-2 are in a
seventh voltage range V7 (< V6).
10 In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is input to the voltage conversion unit
31 by the second connection switching function so as to
allow the voltage level of the final-stage output
15 voltage of the generating elements 20-1 and 20-2 to be
converted by the voltage conversion unit 31.
[0065]
(Series)
The power switch circuit 32 connects the
20 generating elements 20-1 and 20-2 in series by the first
connection switching function when the output voltages
of the generating elements 20-1 and 20-2 are in an
eighth voltage range V8 (< V7 < V6).
In this case, the power switch circuit 32 performs
25 the connection switching such that the generated
electric power is not input to the voltage conversion
unit 31 by the second connection switching function so
as to prevent conversion of the voltage level of either
of the output voltages of the generating elements 20-1
30 and 20-2 by the voltage conversion unit 31.
[0066]
39
SP262791W000
(Series and step-up)
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in series by the first
connection switching function when the output voltages
5 of the generating elements 20-1 and 20-2 are in a ninth
voltage range V9 (< V8 < V7 < V6).
In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is input to the voltage conversion unit
10 31 by the second connection switching function so as to
allow the voltage level of the final-stage output
voltage of the generating elements 20-1 and 20-2 to be
converted by the voltage conversion unit 31.
[0067]
15 (Parallel and step-down)
The power switch circuit 32 connects the
generating elements 20-1 and 20-2 in parallel by the
first connection switching function when the output
voltages of the generating elements 20-1 and 20-2 are in
20 a tenth voltage range Vl0 (> V6 > V7 > V8 > V9).
In this case, the power switch circuit 32 performs
the connection switching such that the generated
electric power is input to the voltage conversion unit
31 by the second connection switching function so as to
25 allow the voltage level of the final-stage output
voltage of the generating elements 20-1 and 20-2 to be
converted by the voltage conversion unit 31.
[0068]
In the above switching controls, the following
30 relationship holds: [(output voltage of generating
elements in the case of series and step-up) < (output
40
SP262791W000
voltage in the case of series) < (output voltage in the
case of series and step-down) < (output. voltage in the
case of parallel) < (output voltage in the case of
parallel and step-down)].
5 [0069]
<4-1-1 Concrete configuration example of power
switch circuit>
Fig. 5 shows a configuration example of the power
switch circuit according to the present embodiment.
10 [0070]
The power switch circuit 32 shown in Fig. 5
includes six switches SWl to SW6 and two diodes Dl and
D2.
Each of the switches SWl to SW6 is constructed of
15 an insulated gate field effect transistor (FET), more
specifically a MOSFET.
The power switch circuit 32 determines the
connection relationship of the maximum two generating
elements (solar batteries SC1 and SC2) 20-1 and 20-2,
20 the voltage conversion unit (step-up/down circuit) 31,
and the electricity storage element (BAT) 40, which is a
secondary battery, by controlling the gate voltage to
the switches SW1 to SW6.
[0071]
25 In the electric power path formed by the power
switch circuit 32 of Fig. 5 from the generating elements
20-1 and 20-2 to the electricity storage element 40,
patterns shown in Figs. 6 and 7 exist.
[0072]
30 A path PTA is formed as a path directly connecting
the generating element (SC2) 20-2 and the electricity
41
SP262791W000
storage element 40, i.e., the secondary battery.
A path PTB is formed as a path supplying the
output electric power from the generating element (SC2)
20-2 to the electricity storage element 40, i.e., the
5 secondary battery, via the voltage conversion unit
(step-up/down circuit) 31.
A path PTC is formed as a path directly connecting
the generating element (SCl) 20-1 and the electricity
storage element 40, i.e., the secondary battery.
10 A path PTD is formed as a path supplying the
output electric power from the generating element (SCl)
20-1 to the electricity storage element 40, i.e., the
secondary battery, via the voltage conversion unit
(step-up/down circuit) 31.
15 A path PTE is formed as a path connecting the
generating element (SCl) 20-1 and the generating element
(SC2) 20-2 in series and directly connecting the
electricity storage element 40, i.e.,the secondary
battery, to the series connection.
20 A path PTF is formed as a path supplying the
output voltage of the generating element (SCl) 20-1 and
the generating element (SC2) 20-2 connected in series to
the electricity storage element 40, i.e., the secondary
battery, via the voltage conversion unit (step-up/down
25 circuit) 31.
A path PTG is formed as a path directly supplying
the output electric power from the generating element
(SCl) 20-1 and the generating element (SC2) 20-2
connected in parallel to the electricity storage element
30 40, i.e., the secondary battery, without passing it
through the voltage conversion unit 31.
42
SP262791W000
A path PTH is formed as a path supplying the
output electric power from the generating element (SCl)
20-1 and the generating element (SC2) 20-2 connected in
parallel to the electricity storage element 40, i.e.,
5 the secondary battery, via the voltage conversion unit
(step-up/down circuit) 31.
A path PTS is formed as a path supplying the
output from the generating element (SC1) to the voltage
conversion unit (step-up/down circuit) 31, connecting
10 the output from the generating element (SC2) 20-2 in
parallel, and supplying the output electric power from
the parallel connection to the electricity storage
element 40, i.e., the secondary battery.
A path PTJ is formed as a path supplying the
15 output from the generating element (SC2) 20-2 to the
voltage conversion unit (step-up/down circuit) 31,
connecting the output from the generating element (SC1)
20-1 in parallel, and supplying the output voltage from
the parallel connection to the electricity storage
20 element 40, i.e., the secondary battery.
A path PTK is formed as a path opening all the
generating element (SC1) 20-1, the generating element
(SC2) 20-2, and the electricity storage element 40. At
this time, the minus side of the generating element
25 (SC2) 20-2 is grounded and used as a path for measuring
the open voltage of the generating element (solar
battery).
A path PTL is formed as a path opening all the
generating element (SCl) 20-1, the generating element
30 (SC2) 20-2, and the electricity storage element 40. At
this time, all of the switches SWl to SW6 are in off-
43
SP262791W000
state. The minus side of the generating element (SC2) is
in open-state.
[0073]
Fig. 8 shows the gate voltage of each of the
5 switches for controlling the electric power path of the
power switch circuit according to the present embodiment
in the form of a truth table.
[0074]
Figs. 9 to 20 show the flow of electric power
10 through the electric power paths PTA to PTL selectively
formed by the power switch circuit according to the
present embodiment.
[0075]
(Path PTA)
15 Fig. 9 shows the flow of electric power through
the electric power path PTA selectively formed by the
power switch circuit according to the present
embodiment.
When the path PTA is selected, the switches SWl
20 and SW6 are controlled to be on while the switches SW2
to SW5 are controlled to be off, so that the
electromotive force (current 12) from the generating
element (SC2) 2 is output to an output terminal VOUT
toward the electricity storage element 40, i.e., the
25 secondary battery.
[0076]
(Path PTB)
Fig. 10 shows the flow of electric power through
the electric power path PTB selectively formed by the
30 power switch circuit according to the present
embodiment.
44
SP262791WO00
When the path PTB is selected, the switches SW1
and SW5 are controlled to be on while the switches SW2
to SW4 and SW6 are controlled to be off, so that the
electromotive force (current 12) from the generating
5 element (SC2) is output to an output terminal DDO toward
the voltage conversion unit (step-up/down circuit) 31.
[0077]
(PathPTC)
Fig. 11 shows the flow of electric power through
i0 the electric power path PTC selectively formed by the
power switch circuit according to the present
embodiment.'
When the path PTC is selected, the switch SW2 is
controlled to be on while the switches SW1, and SW3 to
15 SW6 are controlled to be off, so that the electromotive
force (current I1) from the generating element (SCl) 20-
1 is output to the output terminal VOUT toward the
electricity storage element 40, i.e., the secondary
battery.
20 [0078]
(Path PTD)
Fig. 12 shows the flow of electric power through
the electric power path PTD selectively formed by the
power switch circuit according to the present
25 embodiment.
When the path PTD is selected, the switch SW4 is
controlled to be on and the switches SWl to SW3, SW5,
and SW6 are controlled to be on, so that the
electromotive force (current I1) from the generating
30 element (SCI) 20-1 is output to the output terminal DDO
toward the voltage conversion unit (step-up/down
45
SP262791W000
circuit) 31.
[0079]
(Path PTE)
Fig. 13 shows the flow of electric power through
5 the electric power path PTE selectively formed by the
power switch circuit according to the present
embodiment.
When the path PTE is selected, the switches SW3
and SW6 are controlled to be on while the switches SW1,
10 SW2, SW4,-and SW5 are controlled to be off.
Thus, the electromotive force (current 11) from
the generating element (SCI) 20-1 and the electromotive
force (current 12) from the generating element (SC2) 20-
2 are output in series to the output terminal VOUT
15 toward the electricity storage element 40, i.e., the
secondary battery.
Because the two generating elements 20-1 and 20-2
are connected in series, Il = 12 = Iout (output current
to VOUT).
20 [0080]
(Path PTF)
Fig. 14 shows the flow of electric power through
the electric power path PTF selectively formed by the
power switch circuit according to the present
25 embodiment.
When the path PRF is selected, the switches SW3
and SW5 are controlled to be on while the switches SW1,
SW2, SW4, and SW6 are controlled to be off.
Thus, the electromotive force (current 11) from
30 the generating element (SCl) 20-1 and the electromotive
force (current 12) from the generating element (SC2) 20-
46
SP262791W000
2 are output in series to the output terminal DDO toward
the voltage conversion unit (step-up/down circuit) 31.
Because the two generating elements 20-1 and 20-2
are connected in series, Il = 12 = Iddo (output current
5 to DDO).
[0081]
(Path PTG)
Fig. 15 shows the flow of electric power through
the electric power path PTG selectively formed by the
10 power switch circuit according to the present
embodiment.
When the path PTG is selected, the switches SW1,
SW2, and SW6 are controlled to be on while the switches
SW3 to SW5 are controlled to be off.
15 Thus, the electromotive force (current I1) from
the generating element (SC1) 20-1 and the electromotive
force (current 12) from the generating element (SC2) 20-
2 are output in parallel to the output terminal VOUT
toward the electricity storage element 40, i.e., the
20 secondary battery.
Because the two generating elements 20-1 and 20-2
are connected in parallel, I1 + 12 = Lout (output
current to VOUT).
[0082]
25 (PathPTH)
Fig. 16 shows the flow of electric power through
the electric power path PTH selectively formed by the
power switch circuit according to the present
embodiment.
30 When the path PTH is selected, the switches SW4
and SW5 are controlled to be on while the switches SW1
47
SP262791W000
to SW4 and SW6 are controlled to be off.
Thus, the electromotive force,(current Ii) from
the generating element (SC1) 20-1 and the electromotive
force (current 12) from the generating element (SC2) 20-
5 2 are output in parallel to the output terminal DDO
toward the voltage conversion unit (step-up/down
circuit) 31.
Because the two generating elements 20-1 and 20-2
are connected in parallel, I1 + 12 = Iddo (output
10 current to DDO).
[0083]
(Path PTI)
Fig. 17 shows the flow of electric power through
the electric power path PTI selectively formed by the
15 power switch circuit according to the present
embodiment.
When the path PTI is selected, the switches SWl
and SW6 are controlled to be on while the switches SW2
to SW5 are controlled to be off,
20 Thus, the electromotive force (current Il) from
the generating element (SCl) 20-1 is output to the
output terminal DDO toward the voltage conversion unit
(step-up/down circuit) 31. The electromotive force
(current 12) from the generating element (SC2) 20-2 is
25 output to the output terminal VOUT toward the
electricity storage element 40, i.e., the secondary
battery.
[0084]
(Path PTJ)
30 Fig. 18 shows the flow of electric power through
the electric power path PTJ selectively formed by the
48
SP262791WO00
power switch circuit according to the present
embodiment.
When the path PTJ is selected, the switches SW1,
SW2, and SW5 are controlled to be on while the switches
5 SW3, SW4, and SW6 are controlled to be off.
Thus, the electromotive force (current II) from
the generating element (SCI) 20-1 is output to the
output terminal VOUT toward the electricity storage
element 40, i.e., the secondary battery. The
10 electromotive force (current 12) from the generating
element (SC2) 20-2 is output to the output terminal DDO
toward thevoltage conversion unit (step-up/down
circuit) 31.
[0085]
15 (Path PTK)
Fig. 19 shows the flow of electric power through
the electric power path PTK selectively formed by the
power switch circuit according to the present
embodiment.
20 In the path PTK, the switch SW1 is controlled to
be on while the switches SW2 to SW6 are controlled to be
off.
Thus, the positive electrode sides of the
generating element (SC1) 20-1 and the generating element
25 (SC2) 20-2 are opened, so that no current flows through
the electric power path of the power switch circuit 32.
However, the switch SW1 alone is on so that an
open voltage Vop of the generating element (SCl) 20-1
and the generating element (SC2) 20-2 can be measured.
30 [0086]
(Path PTL)
49
SP262791W000
Fig. 20 shows the flow of electric power through
the electric power path PTL selectively formed by the
power switch circuit according to the present
embodiment.
5 In the path PTL, all of the switches SW1 to SW6
are in off-state, so that there is no current flow
through the electric power path of the power switch
circuit 32.
[0087[
10 According to the present embodiment, one of the
electric power paths such as shown in Fig. 21 is
selected by the control by the first control unit 34 or
the second control unit 35 depending on the environment,
such as illuminance and temperature. Thus, the maximum
15 electric power can be obtained from the generating
elements (solar batteries) 20 at all times regardless of
illuminance or temperature.
For example, when the electric power path is
switched based on illuminance, the electric power path
20 is switched on an illuminance basis as shown in Fig. 22.
There may be a path that does not require switching,
depending on the characteristics or circuit
configuration of the generating elements (solar
batteries) 20.
25 When the illuminance is at the minimum, the
maximum operating point voltage of the generating
elements (solar batteries) 20-1 and 20-2 is very low.
Thus, the generating elements (solar batteries) 20-1 and
20-2 are connected in series so as to increase the
30 voltage, and the voltage is fed to the electricity
storage element 40, i.e., the secondary battery, via the
50
SP262791W000
voltage conversion unit 31.
When the output current from the generating
elements (solar batteries) 20-1 and 20-2 is too low, the
electric power efficiency of the step-up circuit
5 decreases.
When the illuminance is increased to some extent,
the electric power efficiency of the electric power path
PTE becomes higher than that of the electric power path
PTF.
10 This is due to the fact that the maximum operating
point voltage of the generating elements (solar
batteries) 20-1 and 20-2 connected in series without
passing through the voltage conversion unit 31
approaches the charging voltage of the electricity
15 storage element 40, i.e., the secondary battery.
When the illuminance is even higher, the path PTH
connecting the generating elements (solar batteries) 20-
1 and 20-2 in parallel and passing through the step-up
circuit, or the path PTM (the same equivalent circuit as
20 PTH) connecting the solar batteries in series and
passing through the step-down circuit is selected.
When the illuminance is even higher, the
generating elements (solar batteries) 20-1 and 20-2 are
connected in parallel and the electricity storage
25 element 40, i.e., the secondary battery, is fed without
passing through the voltage conversion unit 31.
When the illuminance is at the highest, the
generating elements (solar batteries) 20-1 and 20-2 are
connected in parallel and the secondary battery is fed
30 via the step-down circuit.
The illuminance may be measured by periodically
51
SP262791W000
measuring an open voltage or a short-circuit current of
the generating elements (solar batteries) 20-1 and 20-2.
[0088]
According to the present embodiment with the power
5 switch circuit of the above configuration, the maximum
operating point of the generating element such as the
solar batteries can be controlled to be maintained, thus
providing the advantageous effect that electric power
loss can be avoided.
10 [0089]
In the power switch circuit 32 with the above
configuration, source and drain potentials differ from
one switch to another among the switches SWl to SW6.
Thus, the circuit of each switch is individually
15 designed.
In the power switch circuit 32, the source
potential may take 0 V, Vbat (charging voltage of the
secondary battery), Voc (open voltage: of the solar
battery), or an intermediate value of any of the above,
20 depending an the switch.
In a MOSPET, the threshold value voltage increases
as a substrate-source potential difference Vbs
increases, allowing potential destabilization of an onoff
operation or increase in the on-resistance.
25 Thus, in the power switch circuit 32, the source
and the substrate are short-circuited for both NMOS and
PMOS so that the substrate-source potential difference
Vbs is 0 V.
[0090]
30 The switch SW1 is constructed of an NMOS. The
switches SW2 and SW6 are constructed of PMOS's.
52
SP262791W000
While the power switch circuit 32 is driven from
the first control unit 34 or the second control unit 34,
the control units are designed with logic MOSFETs and
therefore have a low drive capacity. Thus, it may take a
5 long time for switching the switches if the MOSFETs of
the power switch circuit 32 are directly driven.
Accordingly, there is desired a configuration in
which the MOSFETs are driven from the control units via
low gate-capacitance NMOS (MCN) or PMOS (MCP).
10 [0091]
Because the switches SW3, SW4, and SW5 take large
source potential values, a sufficiently large voltage
across gate-source necessary for turning on the switches
may not be obtained.
15 Thus, there is desired a circuit configuration in
which the switches SW3, SW4, and SW5 are provided with a
transmission gate configuration having combined NMOS
with CMOS so that at least one of NMOS and PMOS can be
turned on even when the source potential is large.
20 [0092]
In the power switch circuit 32, the substrate,
potential of the MOSFETs is fixed to the source
potential, so that a parasitic diode may be formed at a
p-n junction portion even when the MOSFETs are off,
25 resulting in conduction.
In the case of NMOS, when the source potential Vs
is higher than the drain potential Vd in off-state,
electrical continuity is established between a p-type
substrate and an n-type diffusion layer. In the case of
30 PMOS, electrical continuity is established between a ptype
diffusion layer and an n-type substrate when the
53
SP262791WO00
drain potential Vd is higher than the source potential
Vs in off-state.
Thus, in the power switch circuit 32, it is
desirable to connect two MOSFETs of the same type in the
5 switches SW2 to SW5, for example, such that the
parasitic diodes are oriented in opposite directions. In
this way, there can be obtained a configuration in which
electrical continuity is not be established even when
either of the potential of the input or output terminals
10 becomes higher.
For example, when the solar battery is connected
to one terminal of a switch and the secondary battery is
connected to the other terminal of the switch, the
voltage (open voltage) on the solar battery side may
15 become higher or lower than the secondary battery
voltage due to illuminance during off-state. Thus, an
anti-parasitic diode measure may be required.
[0093]
Next,, a description is given of the
20 characteristics measurement circuit 33 of the electric
power control circuit and a control of the electric
power path, the voltage conversion unit 31, and the like
by the first control unit 34 depending on a measurement
result from the characteristics measurement circuit 33.
25 [0094]
<4-2. Configuration example of characteristics
measurement circuit and control of electric power path
on basis of measurement result>
The characteristics measurement circuit 33
30 includes the function which measures a short-circuit
current and an open voltage of the generating elements
54
SP262791W000
(SCI, SC2) 20-1 and 20-2.
When an electric power path including the voltage
conversion unit 31, which includes a step-up circuit and
a step-down circuit, is selected, the characteristics
5 measurement circuit 33 performs current-voltage (I-V)
measurement for performing MPPT control in the voltage
conversion unit 31 when a circuit is operated in the
selected electric power path.
[0095]
10 The first control unit 34 performs selection
control of the electric power path of the power switch
circuit 32 on the basis of the measurement result from
the characteristics measurement circuit 33.
When the electric power path including the voltage
15 conversion unit 31, which includes the step-up circuit
and the step-down circuit, is selected, the first
control unit 34 performs MPPT control in the voltage
conversion unit 31 on the basis of a I-V measurement
result when the circuit is operated in the selected
20 electric power path.
[0096]
[Method of controlling characteristics measurement
circuit]
Generally, when charging is to be performed with
25 high energy efficiency on the basis of charging by a
generating element (solar battery), a method involving
MPPT control and using a step-up circuit is used.
According to the present embodiment, in order to
achieve high energy efficiency charging, a control is
30 performed such that the circuit configuration of the
solar battery charging circuit can be optimized by
55
SP262791W000
freely modifying the connection of one or a plurality of
generating elements (solar batteries) or the connection
of the voltage conversion unit (step-up and step-down)
circuit.
5 Specifically, in order to realize an optimum
circuit configuration of the power switch circuit 32, an
optimum control of the power switch circuit 32 is
performed on the basis of the measurement result from
the characteristics measurement circuit 33.
10 [0097]
Fig. 23 illustrates a first function example of
the characteristics measurement circuit according to the
present embodiment.
Fig. 24 illustrates a second function example of
15 the characteristics measurement circuit according to the
present embodiment.
[0098]
A characteristics measurement circuit 33a shown in
Fig. 23 measures an open voltage Vopl and a short-
20 circuit current Ishl of the generating element (SCl) 20-
1 and an open voltage Vop2 and a short-circuit current
Ish2 of the generating element (SC2) 20-2 so as to
obtain electric power path selection information.
The characteristics measurement circuit 33a
25 supplies the measurement result to the first control
unit 34 in the form of a digital signal.
[0099]
30
A characteristics measurement circuit 33b shown in
Fig. 24 measures a voltage VC1 of the generating element
(SCl) 20-1 and a voltage VC2 of the generating element
(SC2) 20-2 so as to perform the I-V measuring operation
56
SP262791W000
for the MPPT control.
The characteristics measurement circuit 33b
determines I and V at several resistor values R so as to
provide the basis for an approximate curve of the I-V
5 curve.
The characteristics measurement circuit 33b
supplies the measurement result to the first control
unit 34 in the form of a digital signal. In this case,
information of the resistor value R is included. The
10 current I during operation is determined by V/R.
[0100]
[Discussion of selection of electric power path]
When there are two generating elements (solar
batteries) 20-1 and 20-2 according to the present
15 embodiment,.a first state and a second state may be
present, as described below.
The first state is a state where at least one of
the two generating elements (solar batteries) 20-1 and
20-2 is operating.
20 The second state is a state where neither of the
two generating elements (solar batteries) 20-1 nor 20-2
is operating.
[0101]
Basically, according to the present embodiment,
25 the first control unit 34 measures a current at a load
side voltage at the time of series connection and a
current at a load side voltage at the time of parallel
connection, and selects the electric power path such
that higher electric power path can be obtained.
30 [0102]
Conditions for selecting the electric power path
57
SP262791WO00
PTA are the following.
Vpm2 < Vddc min (A-1)
Ipm2 < Iddc min (A-2)
Vpm2 * Ipm2 * Eff_ddc (Vpm2, Ipm2) < 12 (Vbat) * &
5 Vbat (A-3)
(A-1) I) (A-2) II (A-3)
When the electric power path PTB is selected, Vref
= Vpm2.
[0103]
10 Eff_ddc(I) indicates electric power efficiency (0
- 1.0) of the step-up circuit of the voltage conversion
unit 31 at the current value I. Eff ddc(I) can be set as
a fixed coefficient at the time of designing.
Vpml indicates an expected voltage of the
15 generating element (SCl) 20-1 at the time of MPPT
control when the open voltage is Vopl.
Vpm2 indicates an expected voltage of the
generating element (SC2) 20-2 at the time of MPPT
control when the open voltage is Vop2.
20 Vddc_min indicates a minimum open voltage as a
threshold value for performing connection change of the
generating elements (solar batteries) 20-1 and 20-2.
Iddc min indicates a short-circuit current as a
threshold value for performing connection change of the
25 generating elements (solar batteries) 20-1 and 20-2.
Vbat indicates a charging voltage of the
electricity storage element 40, i.e., the secondary
battery.
Vref indicates a reference voltage that the first
30 control unit 34 provides to the voltage conversion unit
31 by MTTP control.
58
SP262791W000
[0104]
Conditions for selecting the electric power path
PTC are as follows:
Vpml < Vddc min (C-1)
5 Ipml < Iddc min (C-2)
Vpml * Ipml * Eff ddc (Vpml, Ipml) < Il(Vbat)
Vbat (C-3)
(C-1) 11 (C-2) I) (C-3)
When the electric power path PTD is selected, Vref
10 = Vpml.
[0105]
[Comparison (1) of electric power of paths PTE,
PTF, PTG, PTH, PTI, and PTJ]
Paths with the maximum values of the following (E-
15 1) to (J-1) are selected:
Vbat * Iseries (Vbat) (E-1)
Vpm series * Ipm series * Eff ddc (Vpm series,
Ipm series) (F-1)
The paths are eliminated from candidates when any
20 of the following conditions for operation of the step-up
circuit is not satisfied:
Vpm series > Vddc min
Ipm series > Iddc min
When the electric power path PTFF is selected,
25 Vref = Vpm series.
Vbat * {Il (Vbat) + 12 (Vbat)} (G-1)
Vpm parallel * Ipm parallel * Eff ddc
(Vpm parallel, Ipm parallel) (H-1)
When any of the following conditions for operation
30 of the step-up circuit is not satisfied, the paths are
eliminated from candidates:
59
SP262791W000
Vpm parallel > Vase min
Ipm parallel > Iddc min
When the electric power path PTH is selected, Vref
= Vpm parallel.

CLAIMS
1. An electric power control apparatus comprising:
an electric power path switch unit configured to
5 be connectable with a plurality of generating elements;
and
a voltage conversion unit configured to convert a
voltage level which is generated by the generating
elements and supplied via the electric power path switch
10 unit,
wherein the electric power path switch unit
includes:
a first connection switching function which
switches between series connection and parallel
15 connection for the plurality of generating elements; and
a second connection switching function which
switches between connected and non-connected to an input
side of the voltage conversion unit for the generating
elements connected in series or parallel.
20
2. The electric power control apparatus according to
claim 1,
wherein the electric power path connection unit is
configured to, when output voltages of the generating
25 elements are in a first voltage range, connect the
plurality of generating elements in parallel by the
first connection switching function, and
perform connection switching to a non-connected
state by the second connection switching function such
30 that the voltage level of any of the output voltages of
the plurality of generating elements is not converted by
109
SP262791W000
the voltage conversion unit.
3. The electric power control apparatus according to
claim 1 or 2,
5 wherein the electric power path connection unit is
configured to, when the output voltages of the
generating elements are in a second voltage range,
connect the plurality of generating elements in parallel
by the first connection switching function, and
10 perform the connection switching to a connected
state by the second connection switching function such
that the voltage level of a final-stage output voltage
of the plurality of generating elements is converted by
the voltage conversion unit.
15
4. The electric power control apparatus according to
any one of claims 1 to 3,
wherein the electric power path connection unit is
configured to, when the output voltages of the
20 generating elements are in a third voltage range,
connect the plurality of generating elements in series
by the first connection switching function, and
perform connection switching to a non-connected
state by the second connection switching function such
25 that the voltage level of any of the output voltages of
the plurality of generating elements is not converted by
the voltage conversion unit.
5. The electric power control apparatus according to
30 any one of claims 1 to 4,
wherein the electric power path connection unit is
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SP262791W000
configured to, when the output voltages of the
generating elements are in a fourth voltage range,
connect the plurality of generating elements in series
by the first connection switching function, and
5 perform connection switching to a non-connected
state by the second connection switching function such
that the voltage level of a final-stage output voltage
of the plurality of generating elements is converted by
the voltage conversion unit.
10
6. The electric power control apparatus according to
claim 5,
wherein the first voltage range is higher than the
second voltage range, the second voltage range is higher
15 than the third voltage range, and the third voltage
range is higher than the fourth voltage range.
7. The electric power control apparatus according to
any one of claims 1 to 6,
20 wherein the electric power path connection unit is
configured to, when the output voltages of the
generating elements are in a fifth voltage range,
connect the plurality of generating elements in parallel
by the first connection switching function, and
25 perform connection switching to a connected state
by the second connection switching function such that
the voltage level of a final-stage output voltage of the
plurality of generating elements is converted by the
voltage conversion unit.
30
8. The electric power control apparatus according to
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SP262791W000
claim 7,
wherein the fifth voltage range is higher.than the
first voltage range, the first voltage range is higher
than the second voltage range, the second voltage range
5 is higher than the third voltage range, and the third
voltage range is higher than the fourth voltage range.
9. The electric power control apparatus according to
any one of claims 1 to 8, comprising:
10 a control unit configured to perform MPPT control
by switching an electric power path of the electric
power path switch unit such that a maximum electric
power operating point of the generating elements is
tracked.
15
10. The electric power control apparatus according to
any one of claims 1 to 9, comprising:
a control unit configured to perform MPPT control
in the voltage conversion unit such that a maximum
20 electric power operating point of the generating
elements is tracked in the voltage conversion unit upon
selection of an electric power path including the
voltage conversion unit and when a circuit is operated
in the selected electric power path.
25
11. The electric power control apparatus according to
claim 9 or 10, comprising a characteristics measurement
circuit configured to measure output characteristics of
the plurality of generating elements,
30 wherein the control unit is configured to perform
switching control of the electric power path of the
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SP262791WO00
electric power path switch unit in accordance with a
measurement result from the characteristics measurement
circuit.
5 12. The electric power control apparatus according to
claim 11, wherein
the characteristics measurement circuit includes a
function of measuring a short-circuit current and an
open voltage of the plurality of generating elements,
10 and
the control unit performs the switching control of
the electric power path of the electric power path
switch unit by determining the electric power path in
accordance with the short-circuit current and the open
15 voltage obtained by the characteristics measurement
circuit.
13. The electric power control apparatus according to
claim 12,
20 wherein the control unit is configured to
determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
measurement circuit, and
25 perform the switching control of the electric
power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
30 14. The electric power control apparatus according to
any one of claims 11 to 13,
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SP262791W000
wherein the characteristics measurement circuit is
configured to, upon selection of the electric power path
including the voltage conversion unit and when a circuit
is operated in the selected electric power path, perform
5 current-voltage (I-V) measurement for the MPPT control
for tracking the maximum electric power operating point
of the generating elements in the voltage conversion
unit, and
the control unit is configured to perform the MPPT
10 control in the voltage conversion unit on the basis of a
I-V measurement result.
15. An electric power control method comprising:
when output voltages of a plurality of generating
15 elements are in a first voltage range,
connecting the plurality of generating elements in
parallel by a first connection switching function, and
,performing connection switching to a non-connected
state by a second connection switching function such
20 that a voltage level of any of the output voltages of
the plurality of generating elements is not converted by
a voltage conversion unit;
when the output voltages of the generating
elements are in a second voltage range lower than the
25 first voltage range,
connecting the plurality of generating elements in
parallel by the first connection switching function, and
performing the connection switching to a connected
state by the second connection switching function such
30 that the voltage level of a final-stage output voltage
of the plurality of generating elements is converted by
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SP262791W000
the voltage conversion unit; and
when the output voltages of the generating
elements are in a third voltage range lower than the
second voltage range,
5 connecting the plurality of generating elements in
series by the first connection switching function, and
performing the connection switching to the nonconnected
state by the second connection switching
function such that the voltage level of any of the
10 output voltages of the plurality of generating elements
is not converted by the voltage conversion unit.
16. The electric power control method according to
claim 15, comprising, when the output voltages of the
15 generating elements are in a fourth voltage range lower
than the third voltage range:
connecting the plurality of generating elements in
series by the first connection switching function; and
performing the connection switching to the non-
20 connected state by the second connection switching
function such that the voltage level of the final-stage
output voltage of the plurality of generating elements
is converted by the voltage conversion unit.
25 17. The electric power control method according to
claim 15 or 16, comprising, when the output voltages of
the generating elements are in a fifth voltage range
higher than the first voltage range:
connecting the plurality of generating elements in
30 parallel by the first connection switching function; and
performing the connection switching to the
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SP262791W000
connected state by the second connection switching
function such that the voltage level of the final--stage
output voltage of the plurality of generating elements
is converted by the voltage conversion unit.
5
18. An electric power feeding system comprising:
a plurality of generating elements configured to
generate electric power; and
an electric power control apparatus configured to
10 supply the electric power from the generating elements
to a load side,
wherein the electric power control apparatus
includes
an electric power path switch unit configured to
15 be connectable with the plurality of generating
elements, and
a voltage conversion unit configured to convert a
voltage level which is generated by the generating
elements and supplied via the electric power path switch
20 unit,
wherein the electric power path switch unit
includes
_. a first connection switching function which
switches between series connection or parallel
25 connection for the plurality of generating elements, and
a second connection switching function which
switches between connected and non-connected to an input
side of the voltage conversion unit for the generating
elements connected in series or parallel.
30
19. An electric power control apparatus comprising:
116
SP262791W000
an electric power path switch unit configured to
be connectable with a plurality of generating elements
and including a function of switching between series
connection and parallel connection for the plurality of
5 generating elements;
a characteristics measurement circuit configured
to measure output characteristics of the plurality of
generating elements; and
a control unit configured to perform switching
10 control of an electric power path of the electric power
path switch unit in accordance with a measurement result
from the characteristics measurement circuit.
20. The electric power control apparatus according to
15 claim 19,
wherein the characteristics measurement circuit
includes a function of measuring a short-circuit current
and an open voltage of the plurality, of generating
elements, and
20 the control unit is configured to perform the
switching control of the electric power path of the
electric power path switch unit by determining the
electric power path in accordance with the short-circuit
current and the open voltage obtained by the
25 characteristics measurement circuit.
21. The electric power control apparatus according to
claim 20,
wherein the control unit is configured to
30 determine whether the plurality of generating elements
are in a generating operation state on the basis of the
117
SP262791W000
short-circuit current obtained by the characteristics
measurement circuit, and
perform the switching control of the electric
power path of the electric power path switch unit by
5 determining the electric power path by determining an
operation state on the basis of the open voltage.
22. The electric power control apparatus according to
any one of claims 19 to 21,
10 wherein the control unit includes a function which
performs MPPT control by switching the electric power
path of the electric power path switch unit such that a
maximum electric power operating point of the generating
elements is tracked.
15
23. The electric power control apparatus according to
any one of claims 19 to 22, comprising a voltage
conversion unit configured to convert •a voltage level
which is generated by the generating elements and
20 supplied via the electric power path switch unit,
wherein the electric power path switch unit is
configured to be connectable with the plurality of
generating elements and includes a first connection
switching function which switches between series
25 connection and parallel connection for the plurality of
generating elements, and a second connection switching
function which switches the generating elements
connected to an input side of the voltage conversion
unit,
30 the characteristics measurement circuit is
configured to perform, upon selection of the electric
118
SP262791W000
power path including the voltage conversion unit and
when a circuit is operated in the selected electric
power path, current-voltage (I-V) measurement for MPPT
control such that a maximum electric power operating
5 point of the generating elements is tracked in the
voltage conversion unit, and
the control unit is configured to perform the MPPT
control in the voltage conversion unit on the basis of a
I-V measurement result.
10
24. The electric power control apparatus according to
any one of+claims 19 to 23,
wherein the control unit is configured to measure
a current at a voltage on a load side at the time of
15 series connection and a current at a voltage on the load
side at the time of parallel connection, and select the
electric power path with higher electric power.
25. The electric power control apparatus according to
20 any one of claims 19 to 24,
wherein the characteristics measurement circuit
includes a capacitor connected to an electric power
supply line of the generating elements, and is
configured to measure I-V characteristics by measuring a
25 charging voltage to the capacitor at certain time
intervals.
26. The electric power control apparatus according to
any one of claims 19 to 24,
30 wherein the characteristics measurement circuit
includes:
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SP262791W000
a capacitor connected configured to an electric
power supply line of the generating elements;
a variable voltage source;
a comparator configured to compare a voltage of
5 the electric power supply line with a voltage of the
variable voltage source;
a counter configured to count the time for a
variable voltage to be higher than the voltage of the
electric power supply line; and
10 a controller configured to determine a current
value on the basis of a complementary voltage and a
count value obtained by a voltage increase by AV.
27. The electric power control apparatus according to
15 any one of claims 19 to 24,
wherein the characteristics measurement circuit
includes a resistor connected to the electric power
supply line of the generating elements.
20 28. The electric power control apparatus according to
any one of claims 19 to 24,
wherein the characteristics measurement circuit
includes:
a switch connected to the electric power supply
25 line of the generating element and configured to be
turned on or off by a control signal; and
a resistor connected to the switch.
29. An electric power feeding system comprising:
30 a plurality of generating elements configured to
generate electric power; and
120
SP262791W000
an electric power control apparatus configured to
supply the electric power from the generating elements
to a load side,
wherein the electric power control apparatus
5 includes:
an electric power path switch unit configured to
be connectable with the plurality of generating elements
and including a function which switches between series
connection and parallel connection for the plurality of
10 generating elements;
a characteristics measurement circuit configured
to measure` output characteristics of the plurality of
generating elements; and
a control unit configured to perform switching
15 control of an electric power path of the electric power
path switch unit in accordance with a measurement result
from the characteristics measurement circuit.
30. An electric power control apparatus comprising:
20 a voltage conversion unit configured to convert a
voltage level which is generated by at least one
generating element;
a characteristics measurement circuit configured
to measure output characteristics of the generating
25 element; and
a control unit configured to perform MPPT control
for tracking a maximum electric power operating point of
the generating element in the voltage conversion unit in
accordance with a measurement result from the
30 characteristics measurement circuit,
wherein the voltage conversion unit is configured
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to compare a variable reference voltage with the voltage
level generated by the generating element, and perform
charging or discharging such that the maximum electric
power operating point of the generating element is
5 tracked in accordance with a comparison result, and
the control unit is configured to perform the MPPT
control for tracking the maximum electric power
operating point of the generating element in the voltage
conversion unit by supplying the variable reference
10 voltage on the basis of the measurement result from the
characteristics measurement circuit.
31. The electric power control apparatus according to
claim 30,
15 wherein the characteristics measurement circuit
includes a function of measuring a short-circuit current
and an open voltage of the plurality of generating
elements, and
the control unit is configured to determine the
20 reference voltage in accordance with the short-circuit
current and the open voltage obtained by the
characteristics measurement circuit, and supply the
reference voltage to the voltage conversion unit.
25 32. The electric power control apparatus according to
claim 31, wherein the voltage conversion unit includes:
an inductor connected to an electric power supply
line of the generating elements; and
a switch element configured to perform charging or
30 discharging of energy in the inductor in accordance with
a result of comparison of an input voltage from the
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electric power supply line and the reference voltage,
and
wherein the control unit includes a function which
changes the reference voltage in accordance with
5 increase or decrease of a switching frequency of the
switch element.
33. The electric power control apparatus according to
any one of claims 30 to 32, comprising:
10 a plurality of generating elements; and
an electric power path switch unit configured to
be connectable with the plurality of generating elements
and including a function which switches the generating
elements connected to an input side of the voltage
15 conversion unit,
wherein the characteristics measurement circuit
includes a function of measuring output characteristics
of the plurality of generating elements, and
the control unit is configured to perform
20 switching control of the electric power path of the
electric power path switch unit in accordance with a
measurement result from the characteristics measurement
circuit.
25 34. The electric power control apparatus according to
claim 33,
wherein the electric power path switch unit is
configured to be connectable with the plurality of
generating elements and includes a first connection
30 switching function which switches between series
connection and parallel connection for the plurality of
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generating elements, and a second connection switching
function which switches the generating elements
connected to the input side of the voltage conversion
unit.
5
35. The electric power control apparatus according to
claim 34,
wherein the characteristics measurement circuit
includes a function of measuring a short-circuit current
10 and an open voltage of the plurality of generating
elements, and
the control unit is configured to perform the
switching control of the electric power path of the
electric power path switch unit by determining the
15 electric power path in accordance with the short-circuit
current and the open voltage obtained by the
characteristics measurement circuit.
36. The electric power control apparatus according to
20 claim 35,
wherein the control unit is configured to
determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
25 measurement circuit, and
perform the switching control of the electric
power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
30
37. The electric power control apparatus according to
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any one of claims 33 to 36,
wherein the control unit includes a function which
performs MPPT control by switching the electric power
path of the electric power path switch unit such that a
5 maximum electric power operating point of the generating
elements is tracked.
38. The electric power control apparatus according to
any one of claims 33 to 37,
10 wherein the characteristics measurement circuit is
configured, to, upon selection of the electric power path
including the voltage conversion unit and when a circuit
is operated in the selected electric power path, perform
current-voltage (I-V) measurement for the MPPT control
15 for tracking the maximum electric power operating point
of the generating elements in the voltage conversion
unit, and
the control unit is configured'to perform the MPPT
control in the voltage conversion unit on the basis of a
20 I-V measurement result.
25
39. The electric power control apparatus according to
any one of claims 30 to 38,
wherein the voltage conversion unit includes:
an inductor connected to an electric power supply
line of the generating element;
a switch element for performing charging or
discharging of energy in the inductor;
a comparator configured to compare an input,
30 voltage from the electric power supply line with the
reference voltage; and
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a pulse control unit configured to turn on the
switch element so as to discharge the inductor for a
predetermined time when the input voltage exceeds the
reference voltage according to a comparison result from
5 the comparator.
40. The electric power control apparatus according to
any one of claims 30 to 39,
wherein the characteristics measurement circuit
10 includes a capacitor connected to an electric power
supply line of the generating element, and is configured
to measure I-V characteristics by measuring a charging
voltage to the capacitor at certain time intervals.
15 41. The electric power control apparatus according to
any one of claims 30 to 39,
wherein the characteristics measurement circuit
includes:
a capacitor connected to an electric power supply
20 line of the generating element;
a variable voltage source;
a comparator configured to compare a voltage of
the electric power supply line with a voltage of the
variable voltage source;
25 a counter configured to count the time for a
variable voltage to be higher than the voltage of the
electric power supply line; and
a controller configured to determine a current
value on the basis of a complementary voltage and a
30 count value obtained by a voltage increase by AV.
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42. The electric power control apparatus according to
any one of claims 30 to 39,
wherein the characteristics measurement circuit
includes a resistor connected to an electric power
5 supply line of the generating element.
43. The electric power control apparatus according to
any one of claims 30 to 39,
wherein the characteristics measurement circuit
10 includes:
a switch connected to an electric power supply
line of the generating element and configured to be
turned on or off by a control signal; and
a resistor connected to the switch.
15
44. An electric power feeding system comprising:
at least one generating element configured to
generate electric power; and
an electric power control apparatus configured to
20 supply the electric power from the generating element to
a load side,
wherein the electric power control apparatus
includes:
a voltage conversion unit configured to convert a
25 voltage level generated by the generating element;
a characteristics measurement circuit configured
to measure output characteristics of the generating
element; and
a control unit configured to perform MPPT control
30 for tracking a maximum electric power operating point of
the generating element in the voltage conversion unit in
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accordance with a measurement result from the
characteristics measurement circuit,
wherein the voltage conversion unit is configured
to compare a variable reference voltage with the voltage
5 level generated by the generating element, and perform
charging or discharging such. that the maximum electric
power operating point of the generating elements is
tracked in accordance with a comparison result, and
the control unit is configured to perform the MPPT
10 control for tracking the maximum electric power
operating point of the generating element in the voltage
conversion unit by supplying the variable reference
voltage on the basis of the measurement result from the
characteristics measurement circuit.
15
45. An electric power control apparatus comprising:
an electric power path switch unit configured to
be connectable with a plurality of generating elements
and including a function which switches between series
20 connection and parallel connection for the plurality of
generating elements; and
a backflow prevention circuit disposed in an
electric power supply line for supplying output electric
power from the electric power path switch unit to a
25 load, and including a function which prevents backflow
from a load side when a potential of the load side is
higher than a potential of the electric power supply
line.
30 46. The electric power control apparatus according to
claim 45, comprising a control unit configured to
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terminate the backflow prevention function of the
backflow prevention circuit when the electric power path
switch unit has been switched to parallel connection.
5 47. The electric power control apparatus according to
claim 45 or 46, comprising a voltage conversion unit
configured to convert a voltage level generated by the
generating elements and supplied via the electric power
10
path switch unit,
wherein the electric power path switch unit is
configured,to be connectable with the plurality of
generating elements and includes a first connection
switching function which switches between series
connection and parallel connection for the plurality of
15 generating elements, and a second connection switching
function which switches the generating elements
connected to an input side of the voltage conversion
unit.
20 48. The electric power control apparatus according to
any one of claims 45 to 47, comprising:
a characteristics determination circuit including
a function of measuring a short-circuit current and an
open voltage of the plurality of generating elements;
25 and
a control unit configured to perform switching
control of an electric power path of the electric power
path switch unit by determining the electric power path
in accordance with the short-circuit current and the
30 open voltage obtained by the characteristics measurement
circuit.
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49. The electric power control apparatus according to
claim 48,
wherein the control unit is configured to
5 determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
measurement circuit, and
perform the switching control of the electric
10 power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
50. The electric power control apparatus according to
15 any one of claims 45 to 49, comprising a control unit
including a function which performs MPPT control by
switching the electric power path of the electric power
path switch unit such that a maximum'electric power
operating point of the generating elements is tracked.
20
51. The electric power control apparatus according to
any one of claims 45 to 50, comprising:
__a
voltage conversion unit configured to convert a
voltage level generated by the generating elements and
25 supplied via the electric power path switch unit;
a characteristics measurement circuit configured
to, upon selection of the electric power path including
the voltage conversion unit and when a circuit is
operated in the selected electric power path, perform
30 current-voltage (I-V) measurement for MPPT control for
tracking the maximum electric power operating point of
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the generating elements in the voltage conversion unit;
and
a control unit configured to perform the MPPT
control in the voltage conversion unit on the basis of a
5 S-V measurement result.
52. The electric power control apparatus according to
any one of claims 45 to 51,
wherein the backflow prevention circuit includes:
10 a switch element connected to the electric power
supply lino,
a diode connected to the switch element in
parallel and in a forward direction from the electric
power supply line toward the load; and
15 a comparator configured to compare a potential of
the electric power supply line and the load side
potential across the switch element, and turn on the
switch element when the potential of the electric power
supply line is higher and turn off the switch element
20 when the potential of the electric power supply line is
lower.
53. -An electric power feeding system comprising:
a plurality of generating elements configured to
25 generate electric power; and
an electric power control apparatus configured to
supply the electric power from the generating elements
to a load side,
wherein the electric power control apparatus
30 includes:
an electric power path switch unit configured to
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be connectable with the plurality of generating elements
and including a function which switches between series
connection and parallel connection for the plurality of
generating elements; and
5 a backflow prevention circuit disposed in an
electric power supply line for supplying output electric
power from the electric power path switch unit to a load
and including a function which prevents backflow from
the load side when a potential of the load side is
10 higher than a potential of the electric power supply
line.
54. An electric power control apparatus comprising:
a backflow prevention circuit including a function
15 which prevents backflow from a load side when a
potential of the load side is higher than a potential of
an electric power supply line;
a limit circuit configured to supply electric
power froma generating element to an electricity
20 storage element on the load side and charge the
electricity storage element, and in the limit circuit
that may limit the supplied electric power, the limit
circuit limiting the electric power supply such that a
voltage supplied to the electricity storage element is
25 lower than a full-charge voltage; and
a control unit configured to terminate the
backflow prevention function of the backflow prevention
circuit when the electric power supply is limited by the
limit circuit.
30
55. The electric power control apparatus according to
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claim 54, comprising an electric power path switch unit
configured to be connectable with a plurality of
generating elements and including a function which
switches between series connection and parallel
5 connection for the plurality of generating elements,
wherein the backflow prevention circuit is
disposed in an electric power supply line for supplying
output electric power from the electric power path
switch unit to a load, and configured to prevent
10 backflow from the load side when a potential of the load
side is higher than a potential of the electric power
supply line.
56. The electric power control apparatus according to
15 claim 55, comprising a control unit configured to
terminate the backflow prevention function of the
backflow prevention circuit when the electric power path
switch unit has been switched to parallel connection.
20 57. The electric power control apparatus according to
claim 55 or 56, comprising a voltage conversion unit
configured to convert a voltage level generated by the
generating elements and supplied via the electric power
path switch unit,
25 wherein the electric power path switch unit is
configured to be connectable with the plurality of
generating elements and includes a first connection
switching function which switches between series
connection and parallel connection for the plurality of
30 generating elements, and a second connection switching
function which switches the generating elements
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connected to an input side of the voltage conversion
unit.
58. The electric power control apparatus according to
5 any one of claims 55 to 57, comprising:
a characteristics determination circuit including
a function which measures a short-circuit current and an
open voltage of the plurality of generating elements;
and
10 a control unit configured to perform switching
control of,the electric power path of the electric power
path switch unit by determining the electric power path
in accordance with the short-circuit current and the
open voltage obtained by the characteristics measurement
15 circuit.
59. The electric power control apparatus according to
claim 58,
wherein the control unit is configured to
20 determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
measurement circuit, and
perform the switching control of the electric
25 power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
60. The electric power control apparatus according to
30 any one of claims 55 to 59, comprising a control unit
including a function which performs MPPT control by
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switching the electric power path of the electric power
path switch unit such that a maximum electric power
operating point of the generating elements is tracked.
5 61. The electric power control apparatus according to
any one of claims 55 to 60, comprising:
a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
supplied via the electric power path switch unit;
10 a characteristics measurement circuit configured
to perform, current-voltage (I-V) measurement for MPPT
control for tracking a maximum electric power operating
point of the generating elements in the voltage
conversion unit upon selection of the electric power
15 path including the voltage conversion unit and when a
circuit is operated in the selected electric power path;
and
a control unit configured to perform the MPPT
control in ,the voltage conversion unit on the basis of a
20 I-V measurement result.
25
62. The electric power control apparatus according to
any one of claims 55 to 61,
wherein the backflow prevention circuit includes:
a switch element connected to the electric power
supply line;
a diode connected to the switch element in
parallel and in a forward direction from the electric
power supply line toward the load; and
30 a comparator configured to compare a potential of
the electric power supply line with a load side
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potential across the switch element, and turn on the
switch element when the potential of the electric power.
supply line is higher and turn off the switch element
when the potential of the electric power supply line is
5 lower.
63. An electric power feeding system comprising:
at least one generating element configured to
generate electric power; and
10 an electric power control apparatus configured to
supply the electric power from the generating element to
a load side,
wherein the electric power control apparatus
includes:
15 a backflow prevention circuit including a function
which prevents backflow from the load side when a
potential of the load side is higher than a potential of
an electric power supply line;
a limit circuit configured to supply the electric
20 power from the generating element to an electricity
storage element on the load side for charging the
electricity storage element, and in the limit circuit
that may limit the supplied electric power, the limit
circuit limiting the electric power supply such that a
25 supply voltage to the electricity storage element is
lower than a full-charge voltage; and
a control unit configured to terminate the
backflow prevention function of the backflow prevention
circuit when the electric power supply is limited by the
30 limit circuit.
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64. An electric power control apparatus comprising:
an electric power path switch unit configured to
be connectable with a plurality of generating elements
and including a function which switches between series
5 connection and parallel connection for the plurality of
generating elements; and
a limit circuit configured to supply electric
power from the generating elements to an electricity
storage element on a load side for charging the
10 electricity storage element, and be capable of limiting
the supplied electric power,
wherein the limit circuit is configured to limit
the electric power supply such that a supply voltage
the electricity storage element is lower than a full-
15 charge voltage.
65. The electric power control apparatus according to
claim 64,
wherein the limit circuit includes a function
20 which detects whether a load is connected to the
electricity storage element, and
the limit circuit is configured to, upon detection
of connection of the load to the electricity storage
element, limit the electric power supply such that the
25 supply voltage to the electricity storage element is
lower than the full-charge voltage.
66. The electric power control apparatus according to
claim 64 or 65, comprising:
30 a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
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supplied via the electric power path switch unit; and
a control unit configured to terminate. charging
for the electricity storage element by the limit circuit
and turn off at least a voltage conversion function of
5 the voltage conversion unit when the electricity storage
element on the load side is fully charged.
67. The electric power control apparatus according to
claim 66,
10 wherein the control unit is configured to, when
the supply voltage to the electricity storage element is
lower than'the full-charge voltage, allow charging for
the electricity storage element by the limit circuit and
turn on at least the voltage conversion function of the
15 voltage conversion unit.
68. The electric power control apparatus according to
claim 66 or 67,
wherein the control unit is configured to put an
20 electric power path of the electric power path switch
unit into an open state when charging is terminated.
69. The electric power control apparatus according to
any one of claims 64 to 68, comprising a voltage
25 conversion unit configured to convert a voltage level
generated by the generating elements and supplied via
the electric power path switch unit,
wherein the electric power path switch unit is
configured to be connectable with the plurality of
30 generating elements and includes a first connection
switching function which switches between series
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connection and parallel connection for the plurality of
generating elements, and a second connection switching
function which switches the generating elements
connected to an input side of the voltage conversion
5 unit.
70. The electric power control apparatus according to
any one of claims 64 to 69, comprising:
a characteristics determination circuit including
10 a function which measures a short-circuit current and an
open voltage of the plurality of generating elements;
and
a control unit configured to perform switching
control of an electric power path of the electric power
15 path switch unit by determining the electric power path
in accordance with the short-circuit current and the
open voltage obtained by the characteristics measurement
circuit.
20 71. The electric power control apparatus according to
claim 70,
wherein the control unit is configured to
determine whether the plurality of generating elements
are in a generating operation state on the basis of the
25 short-circuit current obtained by the characteristics
measurement circuit, and
perform the switching control of the electric
power path of the electric power path switch unit by
determining the electric power path by determining an
30 operation state on the basis of the open voltage.
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72. The electric power control apparatus according to
any one of claims 64 to 71, comprising a control unit
including a function which performs MPPT control by
switching an electric power path of the electric power
5 path switch unitsuch that a maximum electric power
operating point of the generating elements is tracked.
73. The electric power control apparatus according to
any one of claims 64 to 72, comprising:
10 a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
supplied via the electric power path switch unit;
acharacteristics measurement circuit configured
to perform current-voltage (I-V) measurement for the
15 MPPT control for tracking the maximum electric power
operating point of the generating elements in the
voltage conversion unit upon selection of the electric
power path including the voltage conversion unit and
when a circuit is operated in the selected electric
20 power path; and
a control unit configured to perform the MPPT
control in the voltage conversion unit on the basis of a
I-V measurement result.
25 74. The electric power control apparatus according to
any one of claims 64 to 73, comprising a backflow
prevention circuit disposed in an electric power supply
line for outputting output voltages of the electric
power path switch unit and the voltage conversion unit
30 to a load,
wherein the backflow prevention circuit includes a
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function which prevents backflow from the load side when
a potential of the load side is higher than a potential
of the electric power supply line.
5 75. The electric power control apparatus according to
claim 74, comprising a control unit configured to
terminate the backflow prevention function of the
backflow prevention circuit when the electric power
supply is limited by the limit circuit.
10
76. The electric power control apparatus according to
claim 74 or 75, comprising a control unit configured to
terminate the backflow prevention function of the
backflow prevention circuit when the electric power path
15 switch unit has been switched to parallel connection.
77. An electric power feeding system comprising:
a plurality of generating elements configured to
generate electric power; and
20 an electric power control apparatus configured to
supply the electric power from the generating elements
to a load side,
wherein the electric power control apparatus
includes:
25 an electric power path switch unit configured to
be connectable with the plurality of generating elements
and including a function which switches between series
connection and parallel connection for the plurality of
generating elements; and
30 a limit circuit configured to supply the electric
power from the generating elements to an electricity
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storage element on the load side for charging the
electricity storage element, and be capable of limiting
the supply voltage,
wherein the limit circuit is configured to limit
5 voltage supply such that the supply voltage to the
electricity storage element is lower than a full-charge
voltage.
78. An electric power control apparatus comprising:
10 an electric power path switch unit configured to
be connectable with a plurality of generating elements
and including a function which switches between series
connection and parallel connection for the plurality of
generating elements;
15 a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
supplied via the electric power path switch unit; and
a control unit configured to perform charging
control by, supplying electric power from the generating
20 elements to an electricity storage element on a load
side by performing switching control of the electric
power path switch unit,
wherein the control unit is configured to perform
switching such that, when a voltage of the electricity
25 storage element is equal to or less than a certain
voltage, the electric power is directly supplied from
the generating elements to the electricity storage
element, and
when the voltage of the electricity storage
30 element is equal to or more than the certain voltage,
operating voltages for the electric power path switch
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unit, the voltage conversion unit, and the control unit
are obtained from the electricity storage element.
79. The electric power control apparatus according to
5 claim 78,
wherein the electric power path switch unit is
configured to be connectable with the plurality of
generating elements and includes a first connection
switching function which switches between series
10 connection and parallel connection for the plurality of
generating elements, and a second connection switching
function which switches the generating elements
connected to an input side of the voltage conversion
unit.
15
80. The electric power control apparatus according to
claim 78 or 79, comprising:
a characteristics determination circuit including
a function which measures a short-circuit current and an
20 open voltage of the plurality of generating elements;
and
a control unit configured to perform switching
control of an electric power path of the electric power
path switch unit by determining the electric power path
25 in accordance with the short-circuit current and the
open voltage obtained by the characteristics measurement
circuit.
81. The electric power control apparatus according to
30 claim 80,
wherein the control unit is configured to
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determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
measurement circuit, and
5 perform the switching control of the electric
power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
10 82. The electric power control apparatus according to
any one of claims 78 to 81, comprising a control unit
including a function which performs MPPT control by
switching an electric power path of the electric power
path switch unit such that a maximum electric power
15 operating point of the generating elements is tracked.
83. The electric power control apparatus according to
any one of claims 78 to 82, comprising:
a characteristics measurement circuit configured
20 to perform current-voltage (I-V) measurement for the
MPPT control for tracking the maximum electric power
operating point of the generating elements in the
voltage conversion unit upon selection of the electric
power path including the voltage conversion unit and
25 when a circuit is operated in the selected electric
power path; and
a control unit configured to perform MPPT control
in the voltage conversion unit on the basis of a I-V
measurement result.
30
84. An electric power feeding system comprising:
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a plurality of generating elements configured to
generate electric power; and
an electric power control apparatus configured to
supply the electric power from the generating elements
5 to a load side,
wherein the electric power control apparatus
includes:
an electric power path switch unit configured to
be connectable with the plurality of generating elements
10 and including a function which switches between series
connection and parallel connection for the plurality of
generating elements;
a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
15 supplied via the electric power path switch unit; and
a control unit configured to perform charging
control by supplying the electric power from the
generating elements to the load side.by performing
switching control of the electric power path switch
20 unit,
wherein the control unit is configured to, when a
voltage of the electricity storage elements is equal to
or less than a certain voltage, directly supply the
electric power from the generating elements to the
25 electricity storage element, and configured to, when the
voltage of the electricity storage element is equal to
or more than the certain voltage, perform the switching
such that operating voltages for the electric power path
switch unit, the voltage conversion unit, and the
30 control unit are obtained from the electricity storage
element.
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85. An electric power control apparatus comprising:
an electric power path unit configured to be
connectable with a plurality of generating elements with
5 different rates of change of a voltage with respect to
illuminance or temperature; and
a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
supplied via the electric power path unit,
10 wherein the electric power path unit is configured
to connect the generating elements with a large rate of
change of the voltage to the voltage conversion unit,
and
put the generating elements with a small rate of
15 change of the voltage in a non-connected state with
respect to the voltage conversion unit.
86. The electric power control apparatus according to
claim 85,
20 wherein the electric power path unit is configured
to connect the generating elements with the large rate
of change of the voltage to the voltage conversion unit
in series, and
connect the generating elements with the small
25 rate of change of the voltage to the generating elements
and the voltage conversion unit that are in series
connection in parallel.
87. The electric power control apparatus according to
30 claim 85 or 86, wherein the electric power path unit
includes an electric power path switch unit,
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wherein the electric power path switch unit is
configured to be connectable•with the plurality of
generating elements and includes a first connection
switching function which switches between series
5 connection and parallel connection for the plurality of
generating elements, and a second connection switching
function which switches the generating elements
connected to an input side of the voltage conversion
unit.
10
88. The electric power control apparatus according to
any one of claims 85 to 87, comprising:
a characteristics determination circuit including
a function which measures a short-circuit current and an
15 open voltage of the plurality of generating elements;
and
a control unit configured to perform switching
control of an electric power path of the electric power
path switch unit by determining the electric power path
20 in accordance with the short-circuit current and he
open voltage obtained by the characteristics measurement
circuit.
89. The electric power control apparatus according to
25 claim 88,
wherein the control unit is configured to
determine whether the plurality of generating elements
are in a generating operation state on the basis of the
short-circuit current obtained by the characteristics
30 measurement circuit, and
perform the switching control of the electric
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power path of the electric power path switch unit by
determining the electric power path by determining an
operation state on the basis of the open voltage.
5 90. The electric power control apparatus according to
any one of claims 85 to 89, comprising a control unit
including a function which performs MPPT control by
switching an electric power path of the electric power
path switch unit such that a maximum electric power
10 operating point of the generating element is tracked.
91. The electric power control apparatus according to
any one of claims 85 to 90, comprising:
a characteristics measurement circuit configured
15 to perform current-voltage (I-V) measurement for MPPT
control for tracking a maximum electric power operating
point of the generating elements in the voltage
conversion unit upon selection of the electric power
path including the voltage conversion unit and when a
20 circuit is operated in the selected electric power path;
and
a control unit configured to perform the MPPT
control in the voltage conversion unit on the basis of a
I-V measurement result.
25
92. An electric power feeding system comprising:
a plurality of generating elements with different
rates of change of a voltage with respect to illuminance
or temperature; and
30 an electric power control apparatus configured to
supply electric power from the generating elements to a
148
SP262791W000
load side,
wherein the.electric power control apparatus
includes:
an electric power path unit configured to be
5 connectable with the plurality of generating elements
with the different rates of change of the voltage with
respect to illuminance or temperature; and
a voltage conversion unit configured to convert a
voltage level generated by the generating elements and
10 supplied via the electric power path unit,
wherein the electric power path unit is configured
to connect the generating elements with a large rate of
change of the voltage to the voltage conversion unit,
and
15 put the generating elements with a small rate of
change of the voltage in a non-connected state with
respec'I; to the voltage conversion unit.