DESCRIPTION
POWER ROUTER AND OPERATION CONTROL METHOD
THEREOF, POWER NETWORK SYSTEM, AND NONS
TRANSITORY COMPUTER READABLE MEDIA STORING
1 0
PROGRAM
Technical Field
[0001]
The present invention relates to a power router and
an operation control method thereof, a power network
system, and a non-transitory computer readable media
storing program.
15 Background Art
[0002]
When a power supply system is constructed, in
addition to a further expansion of a power distribution
grid in a more stable way, a main issue has been
20 providing such a system with a capability of introducing
a large amount of natural energy. A power network
system called Digital Grid (registered trademark) has
been proposed as a new power network (see Patent
literatures 1 and 2.
25 Digital Grid (registered trademark) is a power
network system in which a power network is partitioned
into small-sized cells and these cells are asynchronously
interconnected. Each power cell may be small (e.g., a
house, a building, or a commercial facility) or may be
30 large (e.g., a prefecture or a municipality). Each power
cell naturally includes a load, and may also include a
power generation facility or a power storage system. The
power generation facility may be, as an example, a power
generation facility that uses natural energy generated by,
2
for example, photovoltaic power, wind power, and
geothermal power.
[0003]
In order to freely generate power inside each power
5 cell and to further smoothly interchange power among the
power cells, the power cells are asynchronously
connected. That is, even when the plurality of power
cells are interconnected, a frequency, a phase, and a
voltage of power used in each power cell is asynchronous
10 with those used in other power cells.
Fig. 15 shows an example of a power network system
810. In Fig. 12, a utility grid 811 sends bulk power from
a large-scale power plant 812. A plurality of power cells
821-824 are arranged. Each of the power cells 821-824
15 includes a load such as a house 831 and a building 832,
power generation facilities (e.g., a solar panel 833 and an
wind turbine 834), and a power storage system (e.g., a
storage battery 835).
In the specification of the present application,
20 power generation facilities and power storage systems are
also collectively referred to as "distributed power
supplies".
[0004]
Further, the power cells 821-824 respectively
25 include power routers 841-844 which serve as connection
ports to be connected to other power cells or the utility
grid 811. Each of the power routers 841-844 includes a
plurality of legs (LEG). (Due to space constraints, the
symbols for the legs are omitted in Fig. 15. It should be
30 interpreted that the white circles attached to the power
routers 841-844 are connection terminals of each leg.)
Now, each leg includes a connection terminal and a
power conversion unit, and an address is attached to each
leg. The power conversion by the leg means converting
3
ACto DC or DC to AC and changing the phase, the
frequency, and the voltage of the power.
[0005]
All the power routers 841-844 are connected to a
5 management server 850 by a communication network 851,
and operations of all the power routers 841-844 are
integrally controlled by the management server 850. For
example, the management server 850 instructs each of the
power routers 841-844 to transmit or receive power for
10 each leg. Accordingly, power is interchanged among
power cells through the power routers 841-844.
[0006]
Since power interchange among the power cells is
achieved, a plurality of power cells can share, for
15 example, one power generation facility (e.g., the solar
panel 833 and the wind turbine 834) or one power storage
system (the storage battery 835). If an excessive power
can be interchanged among the power cells, a supplydemand
balance of power can be kept stable while greatly
20 reducing the equipment cost.
Citation List
Patent Literature
[0007]
25 Patent Literature 1: Japanese Patent No. 4783453
Patent Literature 2: Japanese Unexamined Patent
Application Publication No. 2011-182641
Summary of Invention
30 Technical Pt·oblem
[0008]
If a plurality of power cells can be connected by
their power routers 1n an asynchronous manner, this 1s
significantly advantageous. Therefore, it has been
4
desired to commercially implement power routers as soon
as possible.
However, there is a particular problem, which the
conventional power transmission/distribution facility
5 does not have, for actually putting the power router to
practical use. The currently mainstream power
transmission/distribution supposes a power system 1n
which voltage, phase, and frequency are completely
synchronized, so that the power router connecting the
10 power systems that have different voltage, phase, or
frequency needs an attention for new problems.
[0009]
The present invention has been made to solve the
above-described problem and an object thereof is to
15 manage a power router more appropriately when a power
network system in which power cells are asynchronously
connected with each other is constructed.
Solution to Problem
20 [0010]
An aspect of the present invention is a power router
including: a direct current bus in which a voltage thereof
is maintained at a predetermined rating; a plurality of
power conversion legs that bi-directionally converts
25 power between a first connection terminal and a second
connection terminal, the first connection terminal of the
power conversion leg being connected with the direct
current bus, the second connect'ion terminal of the power
conversion leg being connected with an external
30 connection partner as an external connection terminal;
and a control means for controlling operations of the
plurality of power conversion legs. The control means:
determines whether a stopping target leg can be stopped,
based on a control instruction in which a designation of
I
5
the stopping target leg that 1s a target of stopping in the
plurality of power conversion legs is included, and stops
the stopping target leg when the stopping target leg can
be stopped.
5 [0011]
An aspect of the present invention is a power
network system including: one or more power routers; and
a power system that is directly or indirectly connected
with the power router. Each of the one or more power
10 routers includes: a direct current bus the voltage of
which is maintained at a predetermined rating; a plurality
of power conversion legs that bi-directionally converts
power between a first connection terminal and a second
connection terminal, the first connection terminal of the
15 power conversion leg being connected to the direct
current bus, the second connection terminal of the power
conversion leg being connected to an external connection
partner as an external connection terminal; and a control
means for controlling operations of the plurality of power
20 conversion legs. The control means: determines whether
a stopping target leg can be stopped, based on a control
instruction in which a designation of the stopping target
leg that is a target of stopping in the plurality of power
conversion legs is included, and stops the stopping target
25 leg when the stopping target leg can be stopped.
[0012]
An aspect of the present invention is an operation
control method of a power router, the power router
including: a direct current bus the voltage of which is
30 maintained at a predetermined rating; and a plurality of
power conversion legs that bi-directionally converts
power between a first connection terminal and a second
connection terminal, the first connection terminal of the
power conversion leg being connected to the direct
6
current bus, the second connection terminal of the power
conversion leg being connected to an external connection
partner as an external connection terminal. In the power
router, the method including: determining whether a
5 stopping target leg can be stopped, based on a control
instruction in which a designation of the stopping target
leg that is a target of stopping in the plurality of power
conversion legs is included, and stopping the stopping
target leg when the stopping target leg can be stopped.
10 [0013]
An aspect of the present invention is a power router
operation control program, the power router including: a
direct current bus the voltage of which is maintained at a
predetermined rating; a plurality of power conversion
15 legs that bi-directionally converts power between a first
connection terminal and a second connection terminal, the
first connection terminal of the power conversion leg
being connected to the direct current bus, the second
connection terminal of the power conversion leg being
20 connected to an external connection partner as an external
connection terminal; and a computer that configures a
control means for controlling operations of the plurality
of power conversion legs. The program causing the
computer to execute: a process of determining whether a
25 stopping target leg can be stopped, based on a control
instruction in which a designation of the stopping target
leg that is a target of stopping in the plurality of power
conversion legs is included, and a process of stopping the
stopping target leg when the stopping target leg can be
30 stopped.
[0014]
An aspect of the present invention is a management
device control program including: one or more power
routers; a power system that is directly or indirectly
7
connected with the power router; and a computer that
configures a management device controlling operations of
the one or more power routers. Each of the one or more
power routers includes: a direct current bus the voltage
5 of which is maintained at a predetermined rating; a
plurality of power conversion legs that bi-directionally
converts power between a first connection terminal and a
second connection terminal, the first connection terminal
of the power .conversion leg being connected to the direct
10 current bus, the second connection terminal of the power
conversion leg being connected to an external connection
partner as an external connection terminal; and a control
means for controlling operations of the plurality of power
conversion legs. The program causes the computer to
15 execute a process of outputting a control instruction
including a designation of a stopping target leg that 1s a
target leg to be stopped in the plurality of power
conversion legs to the stopping target leg included Ill any
one of the one or more power routers. The control means:
20 determines whether a stopping target leg can be stopped,
and stops the stopping target leg when the stopping target
leg can be stopped.
Advantageous Effects of Invention
25 [0015]
3 0
According to the present invention, it is possible to
manage or control a power router more appropriately when
a power network system in which power cells are
asynchronously connected with each other.
Brief Description of Drawings
[0016]
Fig. 1 is a block diagram illustrating a schematic
configuration of a power router 100;
8
Fig. 2 rs a block diagram of the power router 100
illustrating an example of internal structures of legs;
Fig. 3 Is a block diagram of the power router 100
more specifically illustrating the internal structure of the
5 I e g;
Fig. 4 is a block diagram illustrating a
configuration example of a power router 170 including an
AC through leg 60;
Fig. 5 IS a block diagram schematically showing a
10 relation between a configuration of a control unit 19 and
a stopping target leg;
Fig. 6 is a flow chart showing a stopping procedure
of the stopping target leg in the power router 100;
Fig. 7 is a flow chart showing a procedure of a
15 stopping adequacy determination step S2;
Fig. 8 is a flow chart showing a procedure of a leg
stopping step S3;
Fig. 9 is a flow chart showing a procedure of an
activation of a power conversion leg in a power router
20 200;
Fig. 10 is a flow chart showing a procedure of the
operation mode adequacy determination S5;
Fig. 11 is a flow chart showing a procedure of a leg
activation step S6;
25 Fig. 12 is a block diagram schematically showing a
configuration of a power network system 1001 that is an
example of a power network system;
Fig. 13 is a block diagram schematically showing a
configuration of a power network system 1002 that is an
30 example of a power network system;
Fig. 14 is a block diagram schematically showing a
configuration of a power network system 1003 that is an
example of the power network system; and
Fig. 15 shows an example of the power network
system 810.
Description of Embodiments
[0017]
9
5 Exemplary embodiments of the present invention
will be described below with reference to the drawings.
A specific configuration of the above-described power
router will be described in the following exemplary
embodiments. In this regard, each exemplary embodiment
10 by no means limits the present invention only to a power
router, and it can be understood that the present
invention includes other components such as a device 1n
which the power router is embedded. The same elements
will be assigned the same reference numerals in each
15 drawing, and will not be described when necessary.
[0018]
First exemplary embodiment
S t o p p i n g o f ·a I e g i n c 1 u d e d i n a p o w e r r o u t e r w i 11 b e
described in the present exemplary embodiment. Here, a
20 power router 100 according to a first exemplary
embodiment will be firstly described. The power router
100 is a specific example of above power routers 841 to
844 (Fig. 15). Fig. 1 is a block diagram illustrating a
schematic configuration of the power router 100. The
25 power router 100 typically includes a direct current (DC)
bus 101, a first leg 11, a second leg 12, a third leg 13, a
fourth leg 14 and a control unit 19. In addition, in Fig.
1, the first leg to the fourth leg are indicated as a leg 1
to a leg 4, respectively, for convenience of the drawings.
30 [0019]
The DC bus 101 is connected with the first leg 11 to
the fourth leg 14 1n parallel. The DC bus 101 IS provided
to enable DC power flow. The control unit 19 maintains a
bus voltage V 1 o 1 of the DC bus 101 at a predetermined
10
fixed value by controlling operation states of the first
leg II to the fourth leg 14 (an operation of feeding power
to an outside, an operation of receiving power from the
outside and the like) through a communication bus 102.
5 That is, the power router 100 is connected to the outside
through t.he first leg II to the fourth leg 14. All the
power to be exchanged with the outside is once converted
into DC and the DC flows through the DC bus 101. Since
power is once converted into DC, it is possible to
10 asynchronously connect power cells even when
frequencies, voltages or phases are different.
[0020]
In addition, an example where the power router 100
includes four legs will be described in the present
15 exemplary embodiment. However, the present exemplary
embodiment is only exemplary. The power router can be
provided with an arbitrary number of legs equal to or
more than two legs. In the present exemplary
embodiment, the first leg II to the fourth leg 14 employ
20 the same configuration. However, the two or more legs
included in the power router may employ the same
configuration or different configurations. In addition, a
leg will be also referred to as a power converting leg
below.
25 [0021]
Next, the first leg II to the fourth leg 14 will be
described. Fig. 2 is a block diagram of the power router
100 illustrating an example of internal structures of the
legs. The first leg 11 to the fourth leg 14 employ the
30 same configuration. However, for simplification of the
drawings, Fig. 2 illustrates the internal structures of the
first leg 11 and the second leg 12, and does not illustrate
the internal structures of the third leg 13 and the fourth
leg 14. Fig. 3 is a block diagram of the power router 100
11
more specifically illustrating the internal structure of the
leg. The first leg 11 to the fourth leg 14 employ the
same configuration. However, for simplification of the
drawings, Fig. 3 illustrates the internal structure of the
5 first leg II, and does not illustrate the internal structure
of the second leg 12, the third leg 13, the fourth leg 14
and the communication bus 102.
[0022]
The first leg II to the fourth leg 14 are provided to
10 the DC bus 101 in parallel. As described above, the first
leg 11 to the fourth leg 14 employ the same
configuration. Hereinafter, a configuration of the first
leg 11 will be typically described.
As illustrated in Fig. 2, the first leg II includes a
15 power converting unit Ill, a current sensor 112, a switch
113 and a voltage sensor 114. The first leg 11 is
connected to, for example, a utility grid 811 through a
connection terminal 115. The power converting unit 11"1
converts alternating current (AC) power into DC power or
20 DC power into AC power. DC power flows in the DC bus
101, i.e., the power converting unit Ill converts the DC
power of the DC bus 101 into AC power of a fixed
frequency and voltage and flows the AC power to an
outside from the connection terminal 115. Otherwise, the
25 power conversion unit Ill converts AC power that flows
from the connection terminal 115 into DC power to allow
the DC power to flow through the DC bus 101.
[0023]
The power conversion unit Ill has a configuration
30 of an inverter circuit. More specifically, as illustrated
111 Fig. 3, the power converting unit 111 employs a
configuration in which anti-parallel circuits Ill P formed
of thyristors Ill T and feedback diodes Ill D are threephase
bridge-connected. That is, one inverter circuit
12
(power converting unit Ill) includes the SIX antiparallel
circuits !liP. A wire which is led from a node between
the two anti parallel circuits Ill P and connects this node
with the connection terminal will be referred to as a
5 branch line BL. A three-phase alternating current is
used, and therefore one leg includes the three branch
lines BL in this case. In this regard, a three-phase
inverter circuit is used since the three-phase alternating
current is used. However, a single-phase inverter circuit
10 may be used depending on cases.
[0024]
The switch 113 is disposed between the power
converting unit Ill and the connection terminal 115. By
opening and closing this switch 113, the branch line BL
15 is opened and closed. Thus, the DC bus 101 is isolated
from or connected with the outside. The current sensor
112 and the voltage sensor 114 output detection values to
the control unit 19 through the communication bus 102.
20
[0025]
While the power conversion unit is the inverter
circuit and the connection partner of the leg uses AC as
described above, the connection partner of the leg may
instead use DC and may be, for example, a storage battery
835. (For example, in Fig. 1, the third leg 13 is
25 connected to the storage battery 835.) Power conversion
In this case is DC-DC conversion.
Accordingly, it is possible to provide an inverter
c i r c u i t a n d a, c o n v e r t e r c i r c u i t i n p a r a II e 1 i n the p o w e r
conversion unit and separately use the inverter circuit
30 and the converter circuit depending on whether the
connection partner is AC or DC.
Otherwise, a leg dedicated for DC-DC conversion In
which the power conversion unit is a DC-DC conversion
unit may be provided.
13
In addition, it will be often advantageous in terms
of the size and the cost to use a power router that
includes both a leg dedicated for AC-DC conversion and a
leg dedicated for DC-DC conversion instead of providing
5 the inverter circuit and the converter circuit in parallel
in each leg.
[0026]
The second leg 12 includes a power converting unit
1 2 1 , a cur r e rrt sensor 1 2 2, a switch I 2 3 and a v o 1 tag e
10 sensor 124. The leg 12 is connected to, for example, a
load 830 through a connection terminal 125. The power
converting unit 121, the current sensor 122, the switch
123 and the voltage sensor 124 of the second leg 12
correspond to the power converting unit 111, the current
15 sensor 112, the switch 113 and the voltage sensor 114 of
the first leg 11, respectively. The connection terminal
125 connected with the second leg 12 corresponds to the
connection terminal 115 connected with the first leg 11.
The power converting unit 121 employs a configuration 111
20 which antiparallel circuits 121P each including a
thyristor 121T and a feedback diode 121D are connected
by way of a three-phase bridge. The thyristor 121T, the
feedback diode 121D and the antiparallel circuit 121P
correspond to the thyristor 111 T, the feedback diode !liD
25 and the antiparallel circuit !liP, respectively.
[0027]
The third leg 13 includes a power converting unit
131, a current sensor 132, a switch 133 and a voltage
sensor 134. The third leg 13 is connected to, for
30 example, the battery 835 through a connection terminal
135. The power converting unit 131, the current sensor
132, the switch 133 and the voltage sensor 134 of the
third leg 13 correspond to the power converting unit 111,
the current sensor 112, the switch 113 and the voltage
14
sensor 114 of the first leg 11, respectively. The
connection terminal 135 connected with the third leg 13
corresponds to the connection terminal 115 connected
with the first leg 11. The power converting unit 131
5 employs a configuration in which antipara11e1 circuits
131P each including a thyristor T and a feedback diode
131D are connected by way of a three-phase bridge. The
thyristor 131 T, the feedback diode 131 D and the
antiparallel 131 P correspond to the thyristor 111 T, the
10 feedback diode 111D and the antiparallel circuit lllP,
respectively. In this regard, for simplification of the
drawings, the internal structure of the third leg 13 is not
illustrated in Figs. 2 and 3.
1 5
[0028]
The fourth leg 14 includes a power converting unit
141, a current sensor 142, a switch 143 and a voltage
sensor 144. The fourth leg 14 is connected to, for
example, another power cell through a connection
terminal 145. The power converting unit 141, the current
20 sensor 142, the switch 143 and the voltage sensor 144 of
the fourth leg 14 correspond to the power converting unit
111, the current sensor 112, the switch 113 and the
voltage sensor 114 of the first leg 11, respectively. The
connection terminal 145 connected with the fourth leg 14
25 corresponds to the connection terminal 115 connected
with the first leg 11. The power converting unit 141
employs a configuration in which antiparallel circuits
141P each including a thyristor 141 T and a feedback
diode 141D are connected by way of a three-phase bridge.
30 The thyristor 141T, the feedback diode 141D and the
antiparallel circuit 141P correspond to the thyristor
111 T, the feedback diode 111 D and the antiparallel
circuit lllP, respectively. In this regard, for
simplification of the drawings, the internal structure of
15
the fourth leg 14 IS not illustrated Ill Figs. 2 and 3.
[0029]
The control unit 19 receives a control instruction 52
from the external management server 850 through the
5 communication network 851. The control instruction 52
includes information for instructing an operation of each
leg of the power router 100. In addition, the operation
instruction of each leg includes, for example, a
designation of power transmission/power reception, a
10 designation of an operation mode and a designation of
power to be transmitted or received.
More specifically, the control unit 19 monitors the
bus voltage V,o 1 of the DC bus 101 through a voltage
sensor 103, and controls a power direction, a frequency
15 of AC power and the like. That is, the control unit 19
controls switching of the thyristors lilT, 121T and 131T
and opening/ c 1 o sing of the switches 1 1 3 , 1 2 3 , 1 3 3 and
143 through the communication bus 102.
20
[0030]
In addition, the leg having the power converting
unit has been described above. However, it is also
possible to provide a leg without a power converting unit.
Hereinafter, the leg without the power converting unit
will be temporarily referred to as an AC (Alternating
25 Current) through leg 60. Fig. 4 is a block diagram
illustrating a configuration example of a power router 170
including the AC through leg 60. The power router 170
employing a configuration provided by adding the AC
through leg 60 to the power router 100 will be described.
30 In addition, for simplification of the drawings, the third
leg 13 is not illustrated in Fig. 4.
[0031]
The AC through leg 60 includes a current sensor
162, a switch 163 and a voltage sensor 164. The AC
16
through leg 60 is connected to, for example, another
power cell through a connection terminal 165. A branch
line BL of the AC through leg 60 is connected to the
branch line BL of another leg having the power
5 converting unit through the switch 163. That is, the
connection terminal 165 connected with the AC through
leg 60 is connected to a connection terminal connected
with another leg including the power converting unit.
Fig. 4 illustrates that, for example, the connection
10 terminal 165 connected with the AC through leg 60 is
connected to the connection terminal 145 connected with
the fourth leg 14. Only the switch 163 is provided
between the connection terminal 165 of the AC through
leg 60 and the connection terminal 145 connected with the
15 fourth leg 14, and the AC through leg 60 does not include
a power converter. Hence, power is conducted without
being converted at all between the connection terminal
165 connected with the AC through leg 60 and the
connection terminal 145 connected with the fourth leg 14.
20 Therefore, the leg without a power converter is referred
to as an AC through leg.
[0032]
Fig. 5 is a block diagram schematically showing a
relation between a configuration of the control unit 19
25 and a stopping target leg. In Fig. 5, the case where the
first leg II is designated as the stopping target leg is
represented. The control unit 19 includes a memory unit
191, an operation mode management unit 192, a power
conversion instruction unit 193, aDA/AD conversion unit
30 194, and a sensor-value readout unit 195.
[0033]
The memory unit 191 holds the control instruction
52 from the management server 850 as a control
instruction database 196 (a first database, which IS
.--/;:J .V 17
represented by #JOB in the drawings). The memory unit
191 holds a leg identification information database 197 (a
second database, which is represented by #2DB in the
drawings) for identifying each of the first leg 11 to the
5 fourth leg 14 as well as the control instruction database
196. The memory unit 191 can be achieved by various
types of the memory unit such as a flash memory, etc.
The leg identification information database 197 is
information, e.g., an IP address, URL, URI and so on,
10 allocated for specifying each of the first leg 11 to the
fourth leg 14.
[0034]
The operation mode management unit 192 is
configured by a CPU, for example. The operation mode
15 management unit 192 reads out an operation mode
designation information MODE, which is included tn the
control instruction database 196 and designates an
operation mode (the operation mode will be described
below) of the stopping target leg (the first leg 11). The
20 operation mode management unit 192 also refers to the
leg identification information database 197 in the memory
unit 191 and reads out information (e.g., the IP address)
corresponding to the stopping target leg (the first leg
II). Thus, the operation mode management unit 192 can
25 output an activation instruction with respect to the
stopping target leg (the first leg 11). The operation mode
management unit 192 outputs a waveform instruction
sign a I S D 1 t.h at i s .a . digit a I sign a I . Further, the operation
mode management unit outputs a switching control signal
30 SIGl to the switch (e.g., the switch 113) in the stopping
target leg.
[0035]
The waveform instruction signal SDI is converted
from digital to analog in the DA/AD conversion unit 194,
18
and the converted signal is output to the power
conversion instruction unit 193 as a waveform instruction
signal SAl that is an analog signal. The power
conversion instruction unit 193 outputs a control signal
5 CON to the power converting unit (e.g., the power
converting unit Ill) according to the waveform
instruction signal SAl.
[0036]
The sensor-value readout unit 195 reads the bus
10 voltage V1oi detected by the voltage sensor 103, and a
detected value Ir of the current sensor 112 and a detected
value Vr of the voltage sensor 114 in the stopping target
leg (the first leg 11). The sensor-value readout unit 195
outputs a readout result as a readout signal SA2 that IS an
15 analog signal. The readout signal SA2 is converted from
analog to digital in the DA/AD conversion unit 194, and
the converted signal is output to the operation mode
management unit 192 as a readout signal SD2 that is a
digital signal.
20 [0037]
Next, an operation of the power router 100 will be
described. In the present exemplary embodiment, an
operation mode designation of each leg is included in the
control instruction 52.
25 [0038]
First, the operation mode will be described. As
previously described, the first leg 11 to the fourth leg 14
include the power converting unit 111, 121, 131, and 141,
and the switching operations of the thyristors in the
30 power conversion units are controlled by the control unit
1 9.
The power router 100 is in the node of the power
net w o r k system 8.1 0, and p 1 a y s an important role o f
connecting the utility grid 811, the load 830, a
19
distributed power supply, power cells and the like. At
this time, the connection terminals 115, 125, 135, and
145 of the first leg 11 to the fourth leg 14 are connected
to the utility grid 811, the load 830, the distributed
5 power supply, and power routers of other power cells.
The present inventors have noticed that the first leg 11 to
the fourth leg 14 have different roles depending on the
connection partner and the power routers are not
appropriately operated unless each of the first leg 11 to
10 the fourth leg 14 is appropriately operated according to
each of their respective roles. While the legs have the
same configuration, the present inventors have changed
the method of operating the legs depending on the
connection partner.
15 The method of operating the legs IS called an
operation mode.
The present inventors have prepared three types of
operation modes of the legs, and the modes are switched
according to the connection partner.
20 The operation modes of the legs include:
a master mode;
a stand-alone mode; and
a designated power transmission/reception mode.
In the following description, these operation modes
25 will be described in series.
[0039]
(Master mode)
The master mode is an operation mode when a leg is
connected to a stable power supply source such as an
30 electrical grid, and is an operation mode to keep the
voltage of the DC bus 101. In Fig. 1, an example 111
which the connection terminal 115 of the first leg 11 IS
connected to the utility grid 811 is shown. In the case of
Fig. 1, the operation of the first leg 11 is controlled as a
20
master mode, and plays a role of keeping the voltage VIol
of the DC bus 101. While many other of the second leg
12 to the fourth leg 14 are connected to the DC bus 101,
power may flow into the DC bus 101 from the second leg
5 12 to the fourth leg 14 or may flow out from the second
leg 12 to the fourth leg 14. When the power flows out
through the DC bus 101 and the voltage Vror of the DC
bus 10 I decreases from the rated voltage, the leg first 11
which is in the master mode supplements an insufficient
10 amount of power due to the outflow from the connection
partner (in this example, the utility grid 811). On the
other hand, when the power flows into the DC bus 101 and
the voltage V 1 or of the DC bus 101 increases from the
rated voltage, the first leg 11 which is in the master
15 mode transfers an excessive amount of power due to the
inflow to the connection partner (in this example, the
utility grid 811). The first leg 11 which is in the master
mode is therefore able to keep the voltage Vror of the DC
bus 101.
20 Accordingly, 1n one power router, at least one leg
needs to be operated in the master mode. Otherwise, the
voltage Vror of the DC bus 101 is not kept constant. In
one power router, two or more legs may be operated in the
master mode. It is preferable, however, that only one leg
25 be operated in the master mode rn one power router.
Further, the leg which is in the master mode may be
connected to, for example, the distributed power supply
(also including the storage battery) on which a selfcommutated
inverter is mounted instead of being
30 connected to the utility grid. It is impossible, however,
to connect the leg which is in the master mode and the
distributed power supply on which an externally
commutated inverter is mounted.
[0040]
21
In the following description, the leg operated in the
master mode may be referred to as a master leg.
[0041]
The operation control of the master leg will be
5 described.
The master leg is started as follows.
First, the switch 113 is set to the opened (broken)
state. In this state, the connection terminal 115 is
connected to the connection partner. In this embodiment,
10 the connection partner is the utility grid 811.
The voltage sensor 114 measures the voltage of the
utility grid of the connection partner and obtains the
phase, the frequency, and the amplitude of the voltage of
the utility grid using a phase-locked loop (PLL) or the
15 like. After that, the output of the power conversion unit
111 is adjusted so that the voltage of the phase, the
frequency, and the amplitude that are obtained IS
outputted from the power conversion ·unit Ill. That is,
the ON/OFF patterns of the thyristors 111 T are
20 determined. When this output is made stable, the switch
113 is turned on and the power conversion unit 111 and
the utility grid 811 are connected. Since the output of
the power conversion unit 111 and the voltage of the
utility grid 811 are synchronized at this point, the
25 current does not flow.
[0042]
The operation control when the master leg is
operated will be described.
The bus voltage V 101 of the DC bus 101 is measured
30 by the voltage sensor 103. When the bus voltage V1o1 of
the DC bus 101 exceeds a predetermined rated bus
v o·l tag e, the power conversion unit I 1 1 is con t r o 11 e d so
that power is sent from the master leg (the first leg 11)
to the utility grid 811. (At least one of the phase and
22
the amplitude of the voltage outputted from the power
conversion unit Ill is adjusted so that power is sent from
the DC bus 101 to the utility grid 811 through the master
leg (the first leg 11).) The rated voltage of the DC bus
5 101 1s predetermined.
[0043]
On the other hand, when the bus voltage V 101 of the
DC bus 101 is below the predetermined rated bus voltage,
the power conversion unit Ill is controlled so that the
10 master leg (the first leg 11) IS able to rece1ve power from
the utility grid 811. (At least one of the phase and the
amplitude of the voltage outputted from the power
conversion unit Ill IS adjusted so that power is sent from
the utility grid 811 to the DC bus 101 through the master
15 leg (the first leg 11).) It will be understood that,
according to the operation of the master leg as described
above, the bus v o 1 tag e V 1 o 1 of the DC bus 1 0 1 can be kept
to the predetermined rated voltage.
[0044]
20 (Stand-alone mode)
The stand-alone mode is an operation mode in which
a leg generates a voltage of the amplitude and the
frequency specified by the management server 850 by
itself, and sends power to and receives power from the
25 connection partner.
The stand-alone mode is, for example, an operation
mode to supply power to a device such as the load 830
that consumes power. Alternatively, the stand-alone
mode is an operation mode to directly receive power sent
30 from the connection partner.
Fig. 1 shows an example 1n which the connection
terminal 125 of the second leg 12 is connected to the load
830. The operation of the second leg 12 is controlled as
the stand-alone mode and power is supplied to the load
--:;Jv· ~I i 23
8 3 0.
Further, when a leg is connected to another power
router as in the fourth leg 14, the fourth leg 14 may be
operated in the stand-alone mode as a mode to send
5 energy required by the other power router.
1 0
Alternatively, when a leg is connected to another
power router as in the fourth leg 14, the fourth leg 14
may be operated in the stand-alone mode as a mode to
receive power sent from the other power router.
While it is not illustrated in the drawings, the
second leg can be operated in the stand-alone mode also
in a case in which the second leg is connected to a power
generation facility in place of the load 830. In this case,
however, an externally commutated inverter is installed
15 1n the power generation facility.
The operation mode when the power routers are
connected to each other will be described later.
[0045]
The leg operated in the stand-alone mode is called a
20 stand-alone leg. In one power router, a plurality of
stand-alone legs may be provided.
25
[0046]
The operation control of the stand-alone leg will be
described.
First, a switch 123 is opened (broken). The
connection terminal 125 is connected to the load 830.
The management server 850 notifies the power router 100
of the amp !i.t-u de and the frequency of the power ( v o 1 tag e)
that should be supplied to the load 830. The control unit
30 19 causes the power (voltage) of the specified frequency
and the specified amplitude to be outputted from the
power conversion unit 121 to the load 830. (In short, the
ON/OFF patterns of the thyristors 121T are determined.)
When this output becomes stable, the switch 123 is turned
~-~ /
./
24
on to connect the power conversion unit 121 and the load
830. Lastly, when the power is consumed in the load 830,
the power corresponding to the consumed amount flows
out to the load 830 from the stand~alone leg (the second
5 leg 12).
[0047]
(Designated power transmission/reception mode)
A designated power transmission/reception mode 1s
an operation mode for transmitting or receiving a
10 designated energy. Specifically, the designated power
transmission/reception mode includes a case in which the
designated power is transmitted to the connection partner
and a case in which the designated power is received from
the connection partner.
1 5
20
In Fig. l, the fourth leg 14 1s connected to other
power routers.
In such a case, a predetermined energy is fed from
the fourth leg 14 to the other power router or from the
other power router to the fourth leg 14.
Alternatively, the third leg 13 is connected to the
storage battery 835.
In such a case, a predetermined energy is sent to the
storage battery 835 to charge the storage battery 835.
Further, the designated power
25 transmission/reception leg and the distributed power
supply (also including the storage battery) on which a
self-commutated inverter is mounted may be connected.
However, the designated power transmission/reception leg
and the distributed power supply on which an externally
30 commutated inverter is mounted cannot be connected.
[0048]
The leg operated in the designated power
transmission/reception mode IS called a designated power
transmission/reception leg. In one power router, a
25
plurality of designated power transmission/reception legs
may be provided.
[0049]
The operation control of the designated power
5 transmission/reception leg will be described. Since the
control when the designated power transmission/reception
leg is started is basically the same as that when the
master leg 1s started, a description thereof will be
omitted.
10 [0050]
1 5
The operation control when the designated power
transmission/reception leg 1s operated will be described.
In the following description, symbols attached to the
components of the third leg 13 will be used.
A voltage sensor 134 measures the voltage of the
electrical grid of the connection partner to obtain the
phase and the frequency of the voltage of the connection
partner using a phase-locked loop (PLL) or the like. The
target value of the current that the power conversion unit
20 131 receives or outputs is obtained based on an active
power value and a reactive power value specified by the
management server 850 and the phase and the frequency of
the voltage of the connection partner. A current sensor
132 measures the current value of the current. The power
25 conversion unit 131 is adjusted so that the current
corresponding to the difference between the target value
and the current value is additionally output. (At least
one of the phase and the amplitude of the voltage
outputted from the power conversion unit 131 is adjusted
30 so that a desired power flows between the designated
power transmission/reception leg and the connection
partner.)
[0051]
From the above description, it will be understood
5
26
that the first leg! I to the fourth leg 14 having the same
configuration can play roles having three different
patterns according to the method of the operation control.
[0052]
The power router 100 can cause each leg to operate
1n the three operation modes described above by referring
to the operation mode designation information included 1n
the control instruction 52. Thus, the power router 100
can cause each leg to appropriately operate according to
10 the function thereof.
[0053]
Subsequently, a specific stopping procedure of the
leg is described above. It is necessary to stop the leg
that is in operation to adequately operate the power
15 router 100 described above as appropriate. It is possible
to stop the power router itself and change the operation
mode of the leg in the case of capable of stopping the leg
in operation.
[0054]
20 The stopping target leg (the first leg 1 I) needs to
be normally stopped according to a stopping instruction
for the stopping target leg (the first leg 11) included 1n
the control instruction 52 when the power router that has
been already operated in any operation mode is stopped.
25 In the present exemplary embodiment, the management
server 850 designates the stopping target leg (the first
leg 11) by the control instruction 52. The control unit 19
stops the designated stopping target leg (the first leg
11). Fig. 6 is a flow chart showing a stopping procedure
30 of the stopping target leg (the first leg 11) in the power
router 100. The stopping procedure of the leg in the
power router consists of a stopping instruction reception
step Sl, a stopping adequacy determination step S2, and a
leg stopping step S3.
27
[0055]
Stopping instruction reception step Sl
The control unit 19 receives stopping instruction
information STOP included the control instruction 52
5 output from the management server 850. Specifically, the
operation mode management unit 192 reads out the
stopping instruction information STOP included in the
control instruction database 196 in the memory unit 191.
[0056]
10 Stopping adequacy determination step S2
The control unit 19 checks whether there is a leg
that has already performed a stopping operation other
than the stopping target leg (the first leg II) designated
by the stopping instruction information STOP. Then, the
15 operation mode management unit 192 determines whether
an operation mode of the stopping target leg (the first leg
11) is the master mode. Then, an operation for switching
the leg other than the stopping target leg (the first leg
II) to the master mode is performed.
20 [0057]
Leg stopping step S3
The control unit 19 sets necessary information for
stopping the stopping target leg (the first leg II) in the
designated operation mode to the stopping target leg (the
25 first leg II). Then, the management server 850 is
notified whether the stopping is finished is notified.
[0058]
Subsequently, detail of the stopping adequacy
determination step S2 will be described. Fig. 7 is a flow
30 chart showing a procedure of a stopping adequacy
determination step S2. The stopping adequacy
determination step S2 consists of a stopping possibility
determination step S21, an operation mode determination
step 822, a master mode leg generation step S23, a
28
stopping impossibility notification step S24, and a
stopping process stopping step 825.
[0059]
Stopping possibility determination step S21
5 The operation mode management unit 192 checks
whether there is not a leg that has already performed the
stopping operation other than the stopping target leg (the
first leg 11) designated by the stopping instruction
information STOP. Specifically, the operation mode
10 management unit 192 refers to the control instruction
database 196 in the memory unit 191 to check whether
there is a leg that has already performed the stopping
operation.
[0060]
15 Operation mode determination step S22
When there is not a leg that has already performed
the stopping operation, the operation mode management
unit 192 checks whether the operation mode of the
stopping target leg (the first leg 11) designated by the
20 stopping instruction information STOP is the master
mode.
[0061]
Master mode leg generation step S23
When the operation mode of the stopping target leg
25 (the first leg 11) is the master mode, the operation mode
management unit 192 switches another leg, which is other
than the stopping target leg (the first leg 11), to the
master m o d.e. Ex i s. ten c e o f the master .mode 1 e g is
necessary to adequately operate the power router 100 as
30 described above. Therefore, when the stopping target leg
(the first leg 11) is the master mode leg, another master
mod·e leg needs to be prepared. Thus, the power router
100 performs a process for preparing another master mode
leg by the master mode leg generation step S23.
il/ ~- ,/
29
[0062]
Stopping impossibility notification step S24
When there is a leg that has already performed the
stopping operation, the operation mode management unit
5 192 notifies the management server 850 of an
impossibility of the stopping.
[0063]
Stopping process stopping step S25
The operation mode management unit 192 stops the
10 stopping process since the stopping target leg (the first
leg II) cannot be stopped.
[0064]
Subsequently, detail of the leg stopping step S3
will be described. Fig. 8 is a flow chart showing a
I 5 procedure of the leg stopping step S3. The leg stopping
step S3 consists of an operation mode determination step
S31, a power transmission/reception transition step S32, a
power transmission/reception gradual reduction step S33,
and a finish of the stopping notification step S34.
20 [0065]
Operation mode determination step S31
The operation mode management unit 192 checks
whether the operation mode of the stopping target leg
(the first leg 11) designated by the stopping instruction
25 information STOP is the master mode.
[0066]
Power transmission/reception transition step S32
When the .o. per at ion mode of the stopping target 1 e g
(the first leg I I) is the master mode, the operation mode
30 management unit 192 issues an instruction to the power
conversion unit 1 I I in the stopping target leg (the first
leg 11) and gradually reduces a transmission/reception
power to zero. Simultaneously, the operation mode
management unit I 92 gradually increases a
30
transmission/reception power of the new leg prepared in
the master mode leg generation step S23 and transfers a
master leg function which the stopping target leg (the
first leg 11) is in charge of.
5 [0067]
Power transmission/reception gradual reduction step S33
When the operation mode of the stopping target leg
(the first leg 11) is not the master mode, the operation
mode management unit 192 1ssues the instruction to the
I 0 power conversion unit 111 in the stopping target leg (the
first leg II) and gradually reduces a
transmission/reception power to zero.
[0068]
Finish of stopping notification step S34
15 The operation mode management unit 192 notifies
the management server 850 that the stopping of the
stopping target leg (the first leg II) is finished, and
finishes the process.
[0069]
20 As described above, the power router 100 can stop
the stopping target leg designated by the stopping
instruction from a plurality of the legs to achieve the
stopping instruction of the management server 850.
Specifically, the power router 100 receives the control
25 instruction 52 from the management server 850 by the
control unit 19. The received control instruction 52 is
stored in the memory unit 191 in the control unit 19 as
the control instruction database 196 and read out by the
operation mode management unit 192. The operation mode
30 management unit 192 can specifically designate the
stopping target leg by checking the control instruction
database 196 against the leg identification information
database 197. Then, the operation mode management unit
192 can stop the stopping target leg. That the power
31
router 100 receives the control instruction 52 from the
management server 850 is described above. However, the
operation mode management unit 192 does not receive the
control instruction 52 from the management server 850
5 and the power router 100 can hold the control instruction
52 in advance. Specifically, the memory unit 191 may
hold the control instruction data base 101 and a control
instruction schedule representing the hourly control
instruction 52. The control unit 19 may also generate the
10 control instruction 52 and send the generated control
instruction 52 to the operation mode management unit
I 9 2.
[0070]
Therefore, according to the configuration, it is
15 possible to specifically provide the power router capable
of stopping the stopping target leg disposed in the power
router based on the control instruction 52.
[0071]
Further, the power router 100 can notify the
20 management server 850 whether the designated stopping
target leg can be stopped. Thus, the management server
850 can consider whether the stopping target leg can be
stopped, and activate another leg In the master mode as
appropriate. Thus, it is possible to control to cause the
25 master mode leg to regularly exist in the power router.
[0072]
Second exemplary embodiment
Next, a power router 200 according to a second
exemplary embodiment will be described. The power
30 router 200 is a modification of the power router 100
according to the first exemplary embodiment. The power
router 200 can further change the operation mode after
the stopping t'arget leg described In the first exemplary
embodiment is stopped. That is, In the power router 200,
32
a process to activate the stopped leg in the operation
mode designated by the management server 850 is
performed after the stopping target leg is stopped. Since
a configuration and the stopping operation of the stopping
5 target leg the power router 200 are similar to those of the
power router 100, descriptions of those will be omitted.
[0073]
Subsequently, a specific procedure of activation
after the leg· is stopped when the operation mode is
10 changed will be described. In the present exemplary
embodiment, the management server 850 designates the
operation mode in a manner that the stopping target leg 1s
an activation target leg (the first leg 11). Fig. 9 1s a
flow chart showing a procedure of activation of a power
15 converston leg in a power router 200. The procedure of
activation consists of an operation mode instruction
reception step S4, an operation mode adequacy
determination S5, and a leg activation step S6.
[0074]
20 Operation mode instruction reception step S4
The control unit 19 receives the operation mode
designation information MODE included in the control
instruction 52 output from the management server 850.
Specifically, the operation mode management unit 192
25 reads out the operation mode designation information
MODE included in the control instruction database 196 111
the memory unit 191. Thus, it is possible to figure out
which operation mode the activation target leg should be
switched to.
30 [0075]
Operation mode adequacy determination S5
The control unit 19 determines which of the master
mode, the stand-alone mode, and the designated power
transmission/reception mode is the operation mode of the
33
activation target leg (the first leg 11) designated by the
operation mode designation information MODE. Then, the
control unit 19 determines whether the activation target
leg (the first leg 11) can be activated in the designated
5 operation mode.
[0076]
Leg activation step S6
The control unit 19 sets information necessary for
outputting the power from the activation target leg (the
10 first leg 11) in the designated operation mode to the
activation target leg (the first leg 11). Then, the control
unit 19 notifies the management server 850 whether the
activation is finished.
[0077]
1 5 S u b s e q u e n t I y , d e t a i I o f t h e o p era t i o n m o d e ·a d e q u a c y
determination S5 will be described. Fig. 10 is a flow
chart showing a procedure of the operation mode adequacy
determination S5. The operation mode adequacy
determination S5 includes an operation mode
20 determination step S51, a bus voltage acquisition step
S52, a bus voltage value determination step S53, a bus
voltage defect notification step S54, and an activation
process stopping step S55.
[0078]
25 Operation mode determination step S51
The operation mode management unit 192 determines
which of the master mode, the stand-alone mode, and the
designated power transmission/reception mode is the
operation mode of the activation target leg (the first leg
30 I I) designated by the operation mode designation
information MODE.
[0079]
Bus voltage acquisition step S52
When the operation mode of the activation target
34
leg (the first leg 11) designated by the operation mode
designation information MODE is the master mode, the
operation mode management unit 192 acquires the bns
voltage V1o1 of the DC bus 101 from the voltage 103 via
5 the DA/AD conversion unit 194 and the sensor-value
readout unit 195.
[0080]
Bus voltage value determination step S53
The operation mode management unit 192 determines
10 whether the bus voltage V1o 1 acquired in the bus voltage
acquisition step S52 is equal to or more than a
predetermined value Vth. When the bus voltage V 101 is
equal to or more than the predetermined value Vth, the
flow proceeds to the leg stopping step S6.
15 [0081]
Bus voltage defect notification step S54
When the bus voltage V1o 1 is less than the
predetermined value, the operation mode management unit
192 outputs an alarm of a bus voltage defect to the
20 management server 850.
[0082]
Activation process stopping step S55
The operation mode management unit 192 stops the
activation process after outputting the alarm of the bus
25 voltage defect.
[0083]
Continuously, detail of the leg activation step S6
will be desc.ribed. Fig. 11 is a flow chart showing a
procedure of the leg activation step S6. The leg
30 activation step S6 includes a first operation mode
determination step S61, a master mode waveform
generation step S62, a non-master mode waveform
generation step S63, a switch control step S64, and a
finish of the activation notification step S65.
4.V' fiii{/
35
[0084]
First operation mode determination step S61
The operation mode management unit 192 determines
whether the operation mode of the activation target leg
5 (the first leg II) designated by the operation mode
designation information MODE is the master mode.
[0085]
Master mode waveform generation step S62
The master mode waveform generation step S62 is a
10 step of generating a waveform for the power transmission
in the master mode. The master mode waveform
generation step S62 includes a master mode waveforminformation
acquisition step S621, a waveform model
generation step S622, a difference calculation step S623,
15 an output voltage determination step S624, and an
amplitude synchronization step S625.
[0086]
Master mode waveform-information acquisition step S621
When the operation mode is the master mode, the
20 operation mode management unit 192 acquires voltage
amplitude and a period of the voltage waveform of a
connection partner (e.g., the utility grid) of the
activation target leg (the first leg II). Specifically, the
operation mode management unit 192 acquires a voltage
25 Vr of the branch line BL, which is connected to outside
via the terminal 115, from the voltage sensor 113 via the
DA/AD conversion unit 194 and the sensor-value readout
unit 195. The operation mode management unit 192
acquires the voltage amplitude and the period of the
30 voltage waveform from the acquired voltage Vr. In this
case, for example, the voltage ampli'tude and the period
of the voltage waveform of the connection partner (e.g.,
the utility grid) can be acquired by the so-called zeropoint
detection.
36
[0087]
Waveform model generation step S622
The operation mode management unit 192 generates
a waveform model temporally synchronized with the
5 acquired period. In this case, the waveform model is
generated as a sinusoidal wave.
[0088]
Difference calculation step S623
The operation mode management unit 192 calculates
10 a difference 11V (/1V=VO-V, 0 I) between a rated value VO
of the bus voltage and the present bus voltage V 101 .
[0089]
Output voltage determination step S624
The operation mode management unit 192 determines
15 an output voltage of the activation target leg (the first
leg II) according to the difference 11V.
[0090]
Amplitude synchronization step S625
The operation mode management unit 192
20 synchronizes amplitude of the waveform model with the
determined value of the output voltage. The operation
mode management unit 192 outputs information of the
waveform model in which a synchronization of the
amplitude is finished as the waveform instruction signal
25 SDI. The power conversion instruction unit 193 receives
the waveforminstruction signal SAl that is a signal
converted from the waveform instruction signal SDI by
being converted from digital to analog in the DA/AD
conversion unit 194. Thus, the first leg II finishes a
30 preparation for transmitting the power in synchronization
with the external utility grid as the master leg.
[0091]
Non-master mode waveform generation step S63
The non-master mode waveform generation step S63
37
is a step of generating a waveform for the power
transmission in the operation mode other than the master
mode. The non-master mode waveform generation step
S63 includes a waveform-information acquisition step
5 S631, a waveform model generation step S632, a second
operation mode determination step S633, an output
voltage value acquisition step S634, and an amplitude
synchronization step S635.
[0092]
10 Waveform-information acquisition step S631
Meanwhile, when the operation mode is the standalone
mode or the designated power
transmission/reception, the operation mode management
unit 192 reads out amplitude of the output voltage
15 waveform and a period of the output voltage waveform of
a connection partner (e.g., the leg of other power router,
etc.) of the activation target leg (the first leg 11) from
the control instruction database 196.
[0093]
20 Waveform model generation step S632
The operation mode management unit 192 generates
a waveform model synchronized with the readout
amplitude of the output voltage waveform and period of
the output voltage waveform. In this case, the waveform
25 model is generated as a sinusoidal wave. The operation
mode management unit 192 outputs information of the
generated waveform model as the waveform instruction
signal SDl. The power conversion instruction unit 193
receives the waveform instruction signal SAl that is the
30 signal converted from the waveform instruction signal
SDl by being converted from digital to analog in the
DA/AD conversion unit 194. Thus, the first leg 11
finishes a preparation for transmitting the power to legs
in another external power router and so on as a leg of the
5
38
stand-alone mode and the designated power
transmission/reception mode.
[0094]
Second operation mode determination step S633
The operation mode management unit 192 determines
whether the operation mode of the activation target leg
(the first leg II) designated by the operation mode
designation information MODE is the stand-alone mode.
When the operation mode is the stand-alone mode, the
10 flow proceeds to the switch control step S64.
[0095]
Output voltage value obtaining step S634
When the operation mode 1s the designated power
transmission/reception mode, the operation mode
15 management unit 192 reads out an output power value 1n
the designated power transmission/reception mode from
the control instruction database 196.
[0096]
Amplitude synchronization step S635
20 The operation mode management unit 192
synchronizes amplitude of the waveform model with the
readout output power value. The operation mode
management unit 192 outputs information of the waveform
model in which a synchronization of the amplitude is
25 finished as the waveform instruction signal SDI. The
power conversion instruction unit 193 receives the
waveform instruction signal SAl that is the signal
converted from the waveform instruction signal SDI by
being converted from digital to analog in the DA/AD
30 conversion unit 194. Thus, the first leg II finishes a
preparation for transmitting the power with
synchronization with the external utility grid as the
designated power transmission/reception mode leg.
[0097]
--~v·····' ~I 7
39
Switch control step S64
The operation mode management unit 192 causes the
switch 113 to be in a "close" condition by the switching
control signal SIG1. Thus, the activation target leg (the
5 first leg 11) can transmit the power.
[0098]
Finish of the activation notification step S95
The operation mode notifies the management server
850 of that the activation of the activation target leg (the
10 first leg 11) is finished after the master mode waveform
generation step S62 or the non-master mode waveform
generation step S63.
[0099]
As described above, the power router 200 can
15 activate the activation target leg, which is designated by
the control instruction, in the designated operation mode
to achieve the control instruction of the management
server 850 from a plurality of the legs, in the designated
ope.ration mode. Specifically, the power router 200
20 receives the control instruction 52 from the management
server 850 by the control unit 19. The received control
instruction 52 is stored in the memory unit 191 in the
control unit 19 as the control instruction database 196
and read out by the operation mode management unit 192.
25 The operation mode management unit 192 can specifically
designate the activation target leg (the first leg 11) by
checking the control instruction database 196 against the
leg identification information database 197. Then, the
operation mode management unit 192 can activate the
30 activation target leg (the first leg II) in the designated
operation mode.
[0100]
According to the present configuration, it IS
possible to activate the activation target leg (the first
40
leg 11), which is provided in the power router, in the
designated operation mode based on the control
instruction 52 from the management server 850. Thus, it
is specifically achieve a power router that can cause the
5 power router, which is in operation in any operation
mode, to be in the other operation mode.
[0101]
Third exemplary embodiment
Next, a third exemplary embodiment will be
10 described. In the present exemplary embodiment, an
example of a power network system configured by using
one or more power routers will be described. Note that
the power network system is configured by using power
routers 101 I to 1014, and any power routers according to
15 the first and second exemplary embodiments may be used
as each of the power routers 1011 to 1014.
[0102]
Fig. 12 is a block diagram schematically showing a
configuration of a power network system 1001 that is an
20 example of a power network system. In Fig. 12, for
simplifying the drawing, numerical signs of the legs are
omitted. White circle attached to the power routers I 0 I 1
to 1014 represent connection terminals, respectively.
[0103]
25 Here, a connection line connecting the power router
with connection partner will be complemented. When a
connection line connecting the power routers with each
other is referred to as a power transmission line, the
power transmission line may be a part of the utility grid
30 or separated from the utility grid. In Fig. 12, a
numerical sign 1021 is attached to the power transmission
line that is a part of the utility grid, and a numerical
sign 1022 is attached to the power transmission line that
is separated from the utility grid. That is, a plurality of
41
the power routers are connected with the utility grid. A
power can be interchanged among a plurality of the power
routers via the utility grid by connecting the tow or more
power routers via the utility grid in such manner, so that
5 it is also possible to compensate deficiency and excess of
the interchanged power by the utility grid. Meanwhile,
two or more power routers can be connected with each
other without interposition of the utility grid.
[0104]
10 Further, when a connection line connecting the
power router with the load 830 (or a distributed power
source) is referred to as a power distribution line 1023,
the power distribution line 1023 is separated from the
utility grids 811A to 811C. That is, the power
15 distribution line 1023 that connects the power router with
the load 830 (or a distributed power source) is not
connected with the utility grids 811A to 811C.
[0105]
Another example of the power network system will
20 be described. Fig. 13 is a block diagram schematically
showing a configuration of a power network system 1002
that is an example of a power network system. In Fig.
13, for simplifying the drawing, only the power routers
1011 to 1014 and the utility grid 811 are represented. In
25 Fig. 13, the connection line is represented by a thick
line, and the power distribution line is represented by a
thin line. As shown in Fig. 13, the power routers 1011 to
1014 may be connected in a manner of a bus connection.
Although a description of the operation mode of
30 each leg will be omitted, it will be appreciated that the
operation mode of each leg has to be selected by
appropriately in consideration of a direction of the power
interchange and the connection restriction described
above.
42
Note that, 111 Fig. 13, it will be appreciated that the
utility grid 811 may be replaced with the distributed
power source such as a storage battery and a power
generation facility. That rs, a plurality of the power
5 routers may be connected with the distributed power
source in a manner of the bus connection.
[0106]
Further, another example of the power network
system will be described. Fig. 14 is a block diagram
10 schematically showing a configuration of a power network
system 1003 that is an example of a power network
system. In Fig. 14, for simplifying the drawing, only the
power routers 1011 and 1012 and the utility grid 811 are
represented. In Fig. 14, the connection line is
15 represented by a thick line, and the power distribution
line is represented by a thin line. As shown in Fig. 14, a
configuration in which the power routers 1011 and 1012
are connected with the utility grid 811 may be adopted.
Note that, in Fig. 14, it will be appreciated that the
20 utility grid 811 may be replaced with the distributed
power source.
[0107]
As described above, the utility grid, the distributed
power source including the storage battery and the power
25 facility, and the power routers is regarded as the
connection partner of the power router. In the present
specification and claims, these are referred to as a power
system.
3 0
[0108]
As described above, according to the power router
of the present exemplary embodiment, the effects
described below can be provided.
That is, the power network system in which the
power cells are asynchronously connected with each other
-=Jv ~/
43
can be configured. Then, as described 111 the present
exemplary embodiment, it IS possible to cause the leg In
the power router to operate just as the control instruction
from the management server and specifically manage the
5 power interchange or the like in the power network
system.
[0109]
Other exemplary embodiments
Further, the present invention Is not limited to the
10 above-described exemplary embodiments, and needless to
say, various modifications can be made without departing
from the spirit and scope of the present invention
described above. For example, although the control unit
19 is described as a hardware configuration in the above-
IS described exemplary embodiments, it is not limited to the
hardware configurations. The control unit 19 may be
configured by a computer and arbitrary processing can be
also implemented by causing a CPU (Central Processing
Unit) to execute a computer program. The power
20 converting unit incorporates a control device therein, and
the control devise is, for example, a dynamic
reconfiguration logic (FPGA:Field Programmable Gate
Array). A content of the control program of the FPGA is
changed to suit the mode of the legs, and then the control
25 program operates. Thus, scale of the hardware and a cost
can be decreased, because an operation can be controlled
according to the operation mode by rewriting the FPGA
according to a type of the leg and the operation. The
above-described program can be stored in various types of
30 non-transitory computer readable media and thereby
supplied to computers. The non-transitory computer
readable media includes various types of tangible storage
media. Examples of the non-transitory computer readable
media include a magnetic recording medium (such as a
44
flexible disk, a magnetic tape, and a hard disk drive), a
magneto-optic recording medium (such as a magneto-optic
disk), a CD-ROM (Read Only Memory), a CD-R, and a CDR/
W, a DVD (Digital Versatile Disc), a BD (Blu-ray
5 (registered trademark) Disc), and a semiconductor memory
(such as a mask ROM, a PROM (Programmable ROM), an
EPROM (Erasable PROM), a flash ROM, and a RAM
(Random Access Memory)). Further, the program can be
supplied to computers by using various types of transitory
10 computer readable media. Examples of the transitory
computer readable media include an electrical signal, an
optical signal, and an electromagnetic wave. The
transitory computer readable media can be used to supply
programs to computer through a wire communication path
15 such as an electrical wire and an optical fiber, or
wireless communication path.
[0110]
Although the present invention is explained above
with reference to exemplary embodiments, the present
20 invention is not limited to the above-described exemplary
embodiments. Various modifications that can be
understood by those skilled in the art can be made to the
configuration and details of the present invention within
the scope of the invention.
25 [0111]
3 0
This application is based upon and claims the
benefit of priority from Japanese patent applications No.
2013-013632, filed on January 28,2013, the disclosure of
which is incorporated herein in its entirety by reference.
Reference Signs List
[0112]
11, 21, 31,41 FIRST LEGS
12, 22, 32, 42 SECOND LEGS
til
5
13, 23, 33, 43
45
THIRD LEGS
1 4, 24, 34, 44 FORTH LEGS
I 9 CONTROL UNIT
52 CONTROL INSTRUCTION
60 AC THROUGH LEG
I 0 0, 170, 200, 1011 TO 1 0 I 4
I 0 I DIRECT CURRENT (DC)
102 COMMUNICATION BUS
1 0 3 VOLTAGE SENSOR
POWER ROUTERS
BUS
10 Ill, 121, 131, 141, 151
!liD FEEDBACK DIODE
POWER CONVERTING UNITS
Ill P ANTIPARALLEL CIRCUIT
lilT THYRISTOR
112, 122, 132, 142, 152, 162
15 113, 123, 133, 143, !53, 163
114, 124, 134, 144, 154, 164
CURRENT SENSORS
SWITCHS
VOLTAGE SENSORS
115, 125, 135, 145, 155, 165 CONNECTION TERMINALS
!21T THYRISTOR
191 MEMORY UNIT
20 192 OPERATION MODE MANAGEMENT UNIT
193 POWER CONVERSION INSTRUCTION UNIT
194 DA/AD CONVERSION UNIT
195 SENSOR-VALUE READOUT UNIT
196 CONTROL INSTRUCTION DATABASE (#!DB)
25 197 LEG IDENTIFICATION INFORMATION DATABASE
(#2DB)
810, 1001 TO 1003
8 1 1 , 8 1 1 A TD. 8 I 1 C
POWER NETWORK SYSTEMS
UTILITY GRIDS
812 LARGE-SCALE POWER PLANT
30 821 TO 824POWER CELLS
831 HOUSES
832 BUILDINGS
833 SOLAR PANEL
834 WIND TURBINE
46
835 STORAGE BATTERY
841 TO 844POWER ROUTERS
850 MANAGEMENT SERVER
851 COMMUNICATION NETWORK
5 1021, 1022 CONNECTION LINE
1023 POWER DISTRIBUTION LINE
BL BRANCH LINE
MODE OPERATION MODE DESIGNATION
INFORMATION
10 SAl, SDl WAVEFORM INSTRUCTION SIGNALS
SA2, SD2 READOUT SIGNALS
SCONCONTROL SIGNAL
SIGl SWITCHING CONTROL SIGNAL

CLAIMS
I. A power router comprising:
a direct current bus in which a voltage thereof IS
5 maintained at a predetermined rating;
a plurality of power conversion legs that bidirectionally
converts power between a first connection
terminal and a second connection terminal, the first
connection terminal of the power conversion leg being
I 0 connected with the direct current bus, the second
connection terminal of the power conversion leg being
connected with an external connection partner as an
external connection terminal; and
a control means for controlling operations of the
15 plurality of power conversion legs; wherein
20
25
30
the control means:
determines whether a stopping target leg can be
stopped, based on a control instruction Ill which a
designation of the stopping target 1 e g that I S a target
stopping Ill the plurality of power conversion 1 e g s I S
included; and
stops the stopping target leg when the stopping
target leg can be stopped.
of
2. The power router according to Claim 1, wherein
the control means:
checks whether there is a power conversion leg,
w hi c h 1 s 1 11 a s t o p p i n g o p e r a t i o n , o t h e r t h a n t h e s to p p i 11 g
target leg;
when there is not the power conversion leg, which
IS 111 the stopping operation, other than the stopping
target leg,
determines whether the operation mode of the
stopping target leg is a master mode; and
48
switches the power conversion leg other than
the stopping target leg to the master mode when the
operation mode of the stopping target leg is the master
mode;
5 when there is the power conversion leg, which is in
I 0
the stopping operation, other than the stopping target leg,
notifies outside that the stopping of the stopping target
leg is impossible and stops the stopping of the stopping
target leg.
3. The power router according to Claim 2, wherein
the control means:
determines whether the operation mode of the
stopping target leg is the master mode;
15 when the operation mode of the stopping target leg
is the master mode, gradually reduces a
transmission/reception power of the stopping target leg
and stops a power transmission/reception of the stopping
target leg, and gradually increases a
20 transmission/reception power of the power conversion leg
other than the stopping target leg that is switched to the
master mode, and
when the operation mode of the stopping target leg
IS not the master mode, gradually reduces a
25 transmission/reception power of the stopping target leg
and stops the power transmission/reception of the
stopping target leg, and notifies outside that the stopping
of the stopping target leg is finished after the stopping
target leg is stopped.
30
4. The power router according to any one of Claims
1 to 3, wherein the control means activates the stopping
target leg in another operation mode as an activation
target leg after the stopping target leg is stopped.
49
5. The power router according to Claim 4, wherein
the control means:
receives a control instruction including a
5 designation of an activation target leg in the plurality of
the power conversion legs and a designation of an
operation mode of the activation target leg;
determines whether the activation target leg can be
activated in a designated operation mode; and
10 activates the activation target leg in the designated
1 5
operation mode when the activation target leg can be
activated in the designated operation mode.
6. The power router according to Claim 5, wherein
in the determination, the control means:
determines which of a master mode, a designated
power transmission/reception mode, and a stand-alone
mode is the operation mode designated by the control
20 instruction; and
25
determines whether the activation target leg can be
activated in each operation mode.
7. The power router according to Claim 6, wherein
the contro I means:
acquires the voltage of the direct current bus when
the operation mode designated by the control instruction
is the master mode;
determines that the activation target leg can be
30 activated when the voltage of the direct current bus is
larger than a predetermined value; and
notifies outside of a bus voltage defect and stops
activating the activation target leg when the voltage of
the direct current bus is smaller than the predetermined
5
1 0
50
value.
8. The power router according to Claim 6 or 7,
wherein
when the operation mode designated by the control
instruction is not the master mode, the control means:
determines whether there is a leg operating in the
master mode in the plurality of power conversion legs
other than the activation target leg;
determines that the activation target leg can be
activated when there is the leg operating in the master
mode; and
notifies outside that there is not the leg of the
master mode and stops activating the activation target leg
15 when there is not the leg operating in the master mode.
20
25
9. The power router according to any one of Claims
5 to 8, wherein
the power converston leg comprises:
a power conversion unit that is connected between
the first connection terminal and the second connection
terminal and bi-directionally converts the power between
the first connection terminal and the second connection
terminal;
a current sensor that detects a current flowing
between the power conversion unit and the second
connection terminal;
a switch that is inserted between the power
conversion unit and the second connection terminal and
30 connects or disconnects between the power conversion
unit and the second connection terminal; and
a voltage sensor that detects a voltage between the
switch and the second connection terminal.
51
10. The power router according to Claim 9, wherein
when the activation target leg can be activated, the
control means:
determines which of the master mode, the designated
5 power transmission/reception mode, and the stand-alone
mode is the operation mode designated by the control
instruction; and
I 0
activates the activation target leg 111 a different
condition in each operation mode.
I I. The power router according to Claim I 0,
wherein
when the operation mode designated by the control
instruction is the master mode, the control means:
15 acquires voltage amplitude and a frequency of a
20
25
connection partner from the voltage sensor in the
activation target leg;
generates a waveform model that is temporally
synchronized with the frequency;
calculates a difference between the voltage of the
direct current bus and the voltage amplitude; and
sets amplitude of the waveform model based on the
difference and sets the waveform model to the power
conversion unit in the activation target leg.
12. The power router according to Claim 11,
wherein
when the operation mode designated by the control
instruction is not the master mode, the control means:
30 acqull"es a frequency of a waveform model included
in the control instruction; and
generates a waveform model that 1s temporally
synchronized with the frequency.
52
13. The power router according to Claim 11,
wherein
the control means:
determines which of the designated power
5 transmission/reception mode and the stand-alone mode is
the operation mode designated by the control instruction;
when the operation mode designated by the control
instruction is the designated power
transmission/reception mode,
10 acquires amplitude of a waveform model
included in the control instruction; and
sets the acquired amplitude as the amplitude
of the waveform model and sets the waveform model to
the power conversion unit in the activation target leg;
15 and
20
25
3 0
when the operation mode designated by the control
instruction is the stand-alone mode, sets the generated
waveform model to the power conversion unit in the
activation target leg.
14. The power router according to Claim 12 or 13,
wherein
after setting the waveform mode I of the power
conversion unit, the control means:
controls the switch to connect the power conversion
unit with the second connection terminal; and
notifies outside that the activation is finished.
15. A power network system comprising:
one or more power routers; and
a power system that is directly or indirectly
connected with the power router, wherein
each of the one or more power routers comprises:
a direct current bus the voltage of which is
53
maintained at a predetermined rating;
a plurality of power conversion legs that bidirectionally
converts power between a first connection
terminal and a second connection terminal, the first
5 connection terminal of the power conversion leg being
connected to the direct current bus, the second connection
terminal of the power conversion leg being connected to
an external connection partner as an external connection
terminal; and
10 a control means for controlling operations of
the plurality of power conversion legs,
the control means:
determines whether a stopping target leg can
be stopped, based on a control instruction 111 which a
15 designation of the stopping target leg that 1s a target of
stopping in the plurality of power conversion legs is
included; and
20
25
stops the stopping target leg when the
stopping target leg can be stopped.
16. An operation control method of a power router,
the power router including:
a direct current bus the voltage of which is
maintained at a predetermined rating; and
a plurality of power conversion legs that bidirectionally
converts power between a first connection
terminal and a second connection terminal, the first
connection terminal of the power conversion leg being
connected to the direct current bus, the second connection
30 terminal of the power conversion leg being connected to
an external connection partner as an external connection
terminal,
in the power router, the method comprising:
determining whether a stopping target leg can be
54
stopped, based on a control instruction In which a
designation of the stopping target leg that is a target of
stopping in the plurality of power conversion legs is
included; and
5 stopping the stopping target leg when the stopping
target leg can be stopped.
17. A non-transitory computer readable media
storing a power router operation control program, the
10 power router including:
a direct current bus the voltage of which is
maintained at a predetermined rating;
a plurality of power conversion legs that bidirectionally
converts power between a first connection
15 terminal and a second connection terminal, the first
connection terminal of the power conversion leg being
connected to the direct current bus, the second connection
terminal of the power conversion leg being connected to
an external connection partner as an external connection
20 terminal; and
25
a computer that configures a control means for
controlling operations of the plurality of power
conversion legs,
the program causrng the computer to execute:
a process of determining whether a stopping target
leg can be stopped, based on a control instruction In
which a designation of the stopping target leg that is a
target of stopping in the plurality of power conversion
legs IS included; and
30 a process of stopping the stopping target leg when
the stopping target leg can be stopped.
18. A non-transitory computer readable media
storing a management device control program comprising:
55
one or more power routers;
a power system that is directly or indirectly
connected with the power router; and
' '
a c:omputer that configures a management device
5 con t r o 11 in g opera t i o us of the one or more power routers,
wherein
1 0
each of the one or more power routers comprises:
a direct current bus the voltage· of which is
maintained at a predetermined rating;
_- .il pJ.u r a h'tY o· f power conversion 1 e g s that b idi1:
ectionally converts power between a first connection
te1•minal and a second connection terminal, the first
connection tyrminal of the power conversion leg beiug
connected to the direct current bus, the second connection
15 terminal of the power conversion leg being connected to
an ex,t ernal connection partner as an external connection
20
termitnal; and
a control means for controlling operations of
the plurality of power conversion legs;
the program causes the computer to execute a
process of outputting a control instruction including a
designation of a stopping target leg that is a target leg to
be stopped in the plurality of power conversion legs to
the stopping target leg included in any one of the one or
25 more power routers; and
the control means:
determines whether a stopping target leg can be
stopped; an .. d
stops the stopping target leg when the stopping
30 target leg can be stopped .