FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
RAILWAY VEHICLE SYSTEM;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 100-8310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
5
Field
[0001] The present invention relates to a railway
vehicle system that travels by electric power supplied from
an overhead wire.
10
Background
[0002] In recent railway vehicle systems, relatively
many cases occur in which a railway vehicle becomes unable
to travel due to a trouble of an overhead wire or the like.
15 Patent Literature 1 below discloses an emergency traveling
system that causes a railway vehicle to travel by using
electric power of a storage battery installed on the
railway vehicle even in a case where a trouble occurs in an
overhead wire.
20
Citation List
Patent Literature
[0003] Patent Literature 1: Japanese Patent Application
Laid-open No. 2015-47047
25
Summary
Technical Problem
[0004] In a case of a railway vehicle, since a large
amount of emergency electric power is required, it is
30 necessary to install a plurality of storage batteries.
Therefore, in a case where the technique of Patent
Literature 1 is applied, a plurality of converter devices
for charge of the storage battery are required. For this
3
reason, in the conventional technique, there is a problem
that a size of the system increases and a manufacturing
cost increases.
[0005] The present invention has been made in view of
5 the above, and an object thereof is to obtain a railway
vehicle system enabling to prevent an increase in size of
the system and an increase in manufacturing cost.
Solution to Problem
10 [0006] In order to solve the above-described problem and
achieve the object, a railway vehicle system according to
the present invention includes: a power conversion device
that converts electric power supplied from an overhead wire
into AC power to a load; a plurality of storage batteries
15 that supply emergency electric power for use in a railway
vehicle, to the power conversion device; and charging
circuits that charge the storage batteries. Further, the
railway vehicle system includes: a first opening and
closing device that opens and closes an electrical
20 connection between the overhead wire and the power
conversion device; and a second opening and closing device
that opens and closes an electrical connection between each
of the charging circuits and the overhead wire and an
electrical connection between each of the charging circuits
25 and the power conversion device. The power conversion
device includes a control device that controls opening and
closing of the second opening and closing device and the
charging circuits on the basis of information on a charging
voltage of the plurality of storage batteries. The control
30 device controls the second opening and closing device to be
closed to cause a current supplied from the overhead wire
to flow to the storage battery via the charging circuit.
The charging circuit performs floating charge of the
4
storage battery with a current supplied from the overhead
wire.
Advantageous Effects of Invention
5 [0007] According to the railway vehicle system of the
present invention, it is possible to provide an effect of
preventing an increase in size of the system and an
increase in manufacturing cost.
10 Brief Description of Drawings
[0008] FIG. 1 is a diagram illustrating a configuration
of a railway vehicle system according to an embodiment.
FIG. 2 is a diagram to be used for explaining an
operation in a normal operation in the railway vehicle
15 system according to the embodiment.
FIG. 3 is a diagram to be used for explaining an
operation in emergency traveling in the railway vehicle
system according to the embodiment.
FIG. 4 is a first view to be used for explaining an
20 operation in imbalance of a charging voltage in the railway
vehicle system according to the embodiment.
FIG. 5 is a second view to be used for explaining an
operation in imbalance of a charging voltage in the railway
vehicle system according to the embodiment.
25 FIG. 6 is a third view to be used for explaining an
operation in imbalance of a charging voltage in the railway
vehicle system according to the embodiment.
FIG. 7 is a fourth view to be used for explaining an
operation in imbalance of a charging voltage in the railway
30 vehicle system according to the embodiment.
FIG. 8 is a fifth view to be used for explaining an
operation in imbalance of a charging voltage in the railway
vehicle system according to the embodiment.
5
FIG. 9 is a diagram illustrating a configuration of a
railway vehicle system according to Modification 1 of the
embodiment.
FIG. 10 is a first diagram to be used for explaining
5 an operation in imbalance of a charging voltage in the
railway vehicle system according to Modification 1 of the
embodiment.
FIG. 11 is a second diagram to be used for explaining
an operation in imbalance of a charging voltage in the
10 railway vehicle system according to Modification 1 of the
embodiment.
FIG. 12 is a diagram to be used for explaining an
operation when regenerative power is generated in a railway
vehicle system according to Modification 2 of the
15 embodiment.
FIG. 13 is a diagram illustrating a configuration of a
railway vehicle system according to Modification 3 of the
embodiment.
FIG. 14 is a diagram illustrating a configuration of a
20 railway vehicle system according to Modification 4 of the
embodiment.
FIG. 15 is a block diagram illustrating an example of
a hardware configuration that implements functions of the
control device according to the embodiment.
25 FIG. 16 is a block diagram illustrating another
example of a hardware configuration that implements
functions of the control device in the embodiment.
Description of Embodiments
30 [0009] Hereinafter, a railway vehicle system according
to an embodiment of the present invention will be described
in detail with reference to the accompanying drawings.
Note that the present invention is not limited by the
6
following embodiment.
[0010] Embodiment.
FIG. 1 is a diagram illustrating a configuration of a
railway vehicle system 100 according to an embodiment. The
5 railway vehicle system 100 according to the embodiment
includes a current collection device 2, a first opening and
closing device L1, a second opening and closing device L2,
a power conversion device 3, a load 4, charging circuits 5A
and 5B, and storage batteries 8A and 8B. These components
10 are installed on a railway vehicle 150.
[0011] The current collection device 2 collects DC power
from an overhead wire 1. The current collection device 2
supplies the collected DC power to the power conversion
device 3 via the first opening and closing device L1.
15 Further, the current collection device 2 supplies the
collected DC power to the charging circuits 5A and 5B via
the first opening and closing device L1 and the second
opening and closing device L2. The power conversion device
3 converts DC power supplied from the current collection
20 device 2 into AC power to the load 4.
[0012] An example of the load 4 is a propulsion motor
for railway vehicle driving. Another example of the load 4
is an auxiliary machine. The auxiliary machine is a name
that refers to a load other than the propulsion motor among
25 loads to be installed on the railway vehicle. Examples of
the auxiliary machine are a vehicle interior lighting
device, a door opening and closing device, an air
conditioner, a safety device, a compressor, a battery, and
a control power supply. The compressor is a device that
30 generates an air source of a vehicle brake.
[0013] In a case where the load 4 is a propulsion motor
for railway vehicle driving, a variable voltage variable
frequency (VVVF) inverter is used as the power conversion
7
device 3. Further, in a case where the load 4 is an
auxiliary machine, an auxiliary power supply device is used
as the power conversion device 3.
[0014] The power conversion device 3 includes a control
5 device 3a. The control device 3a drives a switching
element (not illustrated) included in the power conversion
device 3, to control electric power to be supplied to the
load 4.
[0015] The storage batteries 8A and 8B are storage means
10 for electric energy. The storage batteries 8A and 8B
supply emergency electric power for use in the railway
vehicle 150, to the power conversion device 3. Examples of
the storage batteries 8A and 8B are a lithium ion battery,
a nickel hydrogen battery, an electric double layer
15 capacitor, a lithium ion capacitor, and a flywheel. One
storage battery has a configuration in which a plurality of
battery cells are connected in series and parallel.
Therefore, one storage battery is counted as “one group”,
and two storage batteries are counted as “two groups”.
20 This similarly applies to three or more.
[0016] The storage batteries 8A and 8B in FIG. 1 are
examples of a plurality of storage batteries. That is,
although the two-group storage batteries 8A and 8B are
illustrated in FIG. 1, three-group or more storage
25 batteries may be provided. Further, each charging voltage
of the storage batteries 8A and 8B is a voltage lower than
a voltage of the overhead wire 1.
[0017] In correspondence to the storage batteries 8A and
8B, the charging circuits 5A and 5B are respectively
30 provided. The charging circuit 5A is connected between the
second opening and closing device L2 and the storage
battery 8A, and the charging circuit 5B is connected
between the second opening and closing device L2 and the
8
storage battery 8B. The charging circuit 5A charges the
storage battery 8A. The charging circuit 5B charges the
storage battery 8B. In addition, the charging circuit 5A
provides a discharging path when the storage battery 8A
5 discharges. The charging circuit 5B provides a discharging
path when the storage battery 8B discharges.
[0018] The first opening and closing device L1 opens and
closes an electrical connection between the overhead wire 1
and the power conversion device 3. An example of the first
10 opening and closing device L1 is a high-speed breaker. In
addition, since the current collection device 2 also opens
and closes an electrical connection between the overhead
wire 1 and the power conversion device 3, the first opening
and closing device L1 may be the current collection device
15 2. The second opening and closing device L2 opens and
closes an electrical connection between each of the
charging circuits 5A and 5B and the overhead wire 1. In
addition, the second opening and closing device L2 opens
and closes an electrical connection between each of the
20 charging circuits 5A and 5B and the power conversion device
3. An example of the second opening and closing device L2
is a line breaker.
[0019] The charging circuit 5A includes a first switch
L11, a diode D1 that is a unidirectional element, a second
25 switch L12, a resistive element R1, a third switch L13, and
a voltage detector 6A. The first switch L11, the second
switch L12, and the third switch L13 may be switches having
a mechanical structure or may be electrically controlled
switches. The third switch L13 is inserted from the
30 viewpoint of safety, but may be omitted because it is not
directly related to the control of the present embodiment.
[0020] The first switch L11 and the diode D1 are
connected in series to constitute a first circuit. In FIG.
9
1, the first switch L11 is arranged on the second opening
and closing device L2 side, and the diode D1 is arranged on
the storage battery 8A side, but this order may be
reversed. That is, the diode D1 may be arranged on the
5 second opening and closing device L2 side, and the first
switch L11 may be arranged on the storage battery 8A side.
However, in any configuration, a cathode of the diode D1 is
located on the second opening and closing device L2 side,
and an anode of the diode D1 is located on the storage
10 battery 8A side. That is, in the first circuit, the diode
D1 is connected in a direction in which a charging current
from the overhead wire 1 to the storage battery 8A is
blocked.
[0021] The second switch L12 and the resistive element
15 R1 are connected in series to constitute a second circuit.
In FIG. 1, the second switch L12 is arranged on the second
opening and closing device L2 side, and the resistive
element R1 is arranged on the storage battery 8A side, but
this order may be reversed. That is, the resistive element
20 R1 may be arranged on the second opening and closing device
L2 side, and the second switch L12 may be arranged on the
storage battery 8A side.
[0022] The charging circuit 5B includes a first switch
L21, a diode D2 that is a unidirectional element, a second
25 switch L22, a resistive element R2, a third switch L23, and
a voltage detector 6B. A configuration of the charging
circuit 5B is identical to that of the charging circuit 5A,
and a redundant description will be omitted.
[0023] The voltage detector 6A detects a charging
30 voltage V1 of the storage battery 8A. The voltage detector
6B detects a charging voltage V2 of the storage battery 8B.
Detection values of the charging voltages V1 and V2 are
inputted to the control device 3a. The control device 3a
10
controls opening and closing of the second opening and
closing device L2, the first switches L11 and L21, the
second switches L12 and L22, and the third switches L13 and
L23 on the basis of the detection values of the charging
5 voltages V1 and V2.
[0024] Note that, in FIG. 1, the charging circuits 5A
and 5B include the voltage detectors 6A and 6B,
respectively, but the configuration is not limited to this.
In a case where each of the storage batteries 8A and 8B
10 includes a voltage detection function, the detection values
of the storage batteries 8A and 8B may be used. In this
case, the voltage detectors 6A and 6B can be omitted.
[0025] Next, an operation of the railway vehicle system
100 according to the embodiment will be described. FIG. 2
15 is a diagram to be used for explaining an operation in a
normal operation in the railway vehicle system 100
according to the embodiment. FIG. 2 illustrates a flow of
a charging current in the normal operation.
[0026] In the normal operation, the first opening and
20 closing device L1 is controlled to be “closed”. Electric
power of the overhead wire 1 is supplied to the power
conversion device 3 via the first opening and closing
device L1, to drive the load 4. Further, in the normal
operation, the second opening and closing device L2, the
25 second switches L12 and L22, and the third switches L13 and
L23 are controlled to be “closed”. The first switches L11
and L21 may be controlled to be either “open” or “closed”.
Note that, hereinafter, unless otherwise specified, it is
premised that the third switches L13 and L23 are controlled
30 to be “closed”.
[0027] In the railway vehicle system 100 controlled as
described above, there is formed a charging path from the
current collection device 2 to the storage battery 8A via
11
the first opening and closing device L1, the second opening
and closing device L2, the second switch L12, the resistive
element R1, and the third switch L13. As a result, the
storage battery 8A is subjected to floating charge with
5 electric power of the overhead wire 1. Further, in the
storage battery 8B, there is formed a charging path from
the current collection device 2 to the storage battery 8B
via the first opening and closing device L1, the second
opening and closing device L2, the second switch L22, the
10 resistive element R2, and the third switch L23. As a
result, the storage battery 8B is also subjected to
floating charge with electric power of the overhead wire 1.
The operation illustrated in FIG. 2 is performed when the
railway vehicle 150 stops at a vehicle base or a station,
15 or travels in an electrified section.
[0028] As described above, in the railway vehicle system
100 according to the embodiment, the storage batteries 8A
and 8B can be charged without using a converter device.
This makes it possible to prevent an increase in size of
20 the system and an increase in manufacturing cost. In
addition, since the storage batteries 8A and 8B are charged
in the normal operation, it is possible to secure a
necessary battery capacity even in a case of floating
charge.
25 [0029] Next, an operation in emergency traveling will be
described. FIG. 3 is a diagram to be used for explaining
an operation in emergency traveling in the railway vehicle
system 100 according to the embodiment. FIG. 3 illustrates
a flow of a discharging current in the emergency traveling.
30 Note that the “emergency traveling” is an operation of
moving the railway vehicle 150 to a safe position or a
position where the normal operation is not hindered, by
using electric power of the storage batteries 8A and 8B,
12
when a trouble occurs in the overhead wire 1 or the like
and electric power supply from the overhead wire 1 is
interrupted. Note that, in a case where the load 4 is an
auxiliary machine and the power conversion device 3 is an
5 auxiliary power supply device, this operation is replaced
as an operation of supplying electric power to the
auxiliary machine of the railway vehicle 150 by using
electric power of the storage batteries 8A and 8B when a
trouble occurs in the overhead wire 1 or the like and the
10 electric power supply from the overhead wire 1 is
interrupted.
[0030] When a trouble occurs in the overhead wire 1 or
the like, the first opening and closing device L1 is
controlled to be “open” by a higher-order control device
15 (not illustrated). At this time, the second opening and
closing device L2 and the first switches L11 and L21 are
controlled to be “closed” by the control device 3a. Note
that the second switches L12 and L22 may be controlled to
be either “open” or “closed”.
20 [0031] In the railway vehicle system 100 controlled as
described above, there is formed a current path from the
storage battery 8A to the power conversion device 3 via the
third switch L13, the diode D1, the first switch L11, and
the second opening and closing device L2. Further, there
25 is formed a current path from the storage battery 8B to the
power conversion device 3 via the third switch L23, the
diode D2, the first switch L21, and the second opening and
closing device L2. As a result, electric power of the
storage batteries 8A and 8B can be supplied to a VVVF
30 inverter (not illustrated in FIG. 3) which is one of the
power conversion device 3, to drive a propulsion motor (not
illustrated in FIG. 3) which is one of the load 4. As a
result, the railway vehicle 150 can be moved to a safe
13
position or a position where the normal operation is not
hindered.
[0032] Next, an operation in imbalance of a charging
voltage will be described with reference to the drawings of
5 FIGS. 4 to 8. FIG. 4 is a first view to be used for
explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100 according to the
embodiment. FIG. 5 is a second view to be used for
explaining an operation in imbalance of a charging voltage
10 in the railway vehicle system 100 according to the
embodiment. FIG. 6 is a third view to be used for
explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100 according to the
embodiment. FIG. 7 is a fourth view to be used for
15 explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100 according to the
embodiment. FIG. 8 is a fifth view to be used for
explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100 according to the
20 embodiment.
[0033] For a voltage difference ΔV=V1-V2 between the
charging voltage V1 of the storage battery 8A and the
charging voltage V2 of the storage battery 8B, FIG. 4
illustrates a flow of a charging/discharging current when
25 ΔV>A is satisfied. Further, for a voltage difference
ΔV=V2-V1 between the charging voltage V2 of the storage
battery 8B and the charging voltage V1 of the storage
battery 8A, FIG. 5 illustrates a flow of a
charging/discharging current when ΔV>A is satisfied. The
30 reference character “A” is a threshold value for
determining imbalance of a charging voltage. That is, in
the present embodiment, a state in which ΔV>A is satisfied
is defined as a state in which imbalance occurs in a
14
charging voltage. Note that, in the following description,
the threshold value A may be referred to as a “first
threshold value”.
[0034] When the voltage difference ΔV exceeds the
5 threshold value A, the second opening and closing device L2
is controlled to be “open”, and the first switches L11 and
L21 and the second switches L12 and L22 are controlled to
be “closed”.
[0035] In the railway vehicle system 100 controlled as
10 described above, in the example of FIG. 4, there is formed
a charging path from the storage battery 8A to the storage
battery 8B via the third switch L13, the diode D1, the
first switch L11, the second switch L22, the resistive
element R2, and the third switch L23. This enables the
15 storage battery 8B to be charged with electric power of the
storage battery 8A.
[0036] Further, in the example of FIG. 5, there is
formed a charging path from the storage battery 8B to the
storage battery 8A via the third switch L23, the diode D2,
20 the first switch L21, the second switch L12, the resistive
element R1, and the third switch L13. This enables the
storage battery 8A to be charged with electric power of the
storage battery 8B.
[0037] The above operation enables mutual charging
25 between the storage battery 8A and the storage battery 8B.
[0038] Further, in FIGS. 4 and 5, when the voltage
difference ΔV decreases to the threshold value A or less,
the second opening and closing device L2 is controlled to
be “closed”. As a result, floating charge of the storage
30 batteries 8A and 8B is restarted.
[0039] In the examples of FIGS. 4 and 5, charging and
discharging when the voltage difference ΔV is relatively
small has been described. Whereas, in a case where the
15
voltage difference ΔV is relatively large, the charging
circuits 5A and 5B are controlled to have current paths
different from those in FIGS. 4 and 5.
[0040] FIG. 6 illustrates a time-change waveform of the
5 voltage difference ΔV. A horizontal axis represents time.
In parallel with the horizontal axis, two broken lines are
drawn. The lower broken line indicates a level of the
threshold value A described above. Further, the upper
broken line of the two broken lines indicates a level of a
10 threshold value B, which is a second threshold value. As
illustrated, the threshold value B has a value larger than
the threshold value A. Note that, in the following
description, the threshold value B may be referred to as a
“second threshold value”.
15 [0041] For a voltage difference ΔV=V2-V1 between the
charging voltage V2 of the storage battery 8B and the
charging voltage V1 of the storage battery 8A, FIG. 7
illustrates a flow of a charging/discharging current when
ΔV>B is satisfied. In addition, for the voltage difference
20 ΔV=V2-V1 between the charging voltage V2 of the storage
battery 8B and the charging voltage V1 of the storage
battery 8A, FIG. 8 illustrates a flow of a
charging/discharging current when A<ΔV≤B is satisfied.
Note that the current path in FIG. 7 is formed when the
25 voltage difference ΔV falls within a range of (1) in FIG.
6, and the current path in FIG. 8 is formed when the
voltage difference ΔV falls within a range of (2) in FIG.
6.
[0042] In a case of the example of FIG. 7 in which the
30 voltage difference ΔV exceeds the threshold value B, the
second opening and closing device L2 and the first switch
L21 are controlled to be “open”, and the second switches
L12 and L22 are controlled to be “closed”. The first
16
switch L11 may be controlled to be either “open” or
“closed”.
[0043] In the railway vehicle system 100 controlled as
described above, there is formed a charging path from the
5 storage battery 8B to the storage battery 8A via the third
switch L23, the resistive element R2, the second switch
L22, the second switch L12, the resistive element R1, and
the third switch L13. This enables the storage battery 8A
to be charged with electric power of the storage battery
10 8B. This charging path is to be a path passing through the
two resistive elements R1 and R2. Therefore, if the
threshold value B and the resistance values of the
resistive elements R1 and R2 are appropriately set, the
charging current can be reduced. This makes it possible to
15 reduce the charging current without providing a special
current adjustment means.
[0044] Further, in a case of the example of FIG. 8 in
which the voltage difference ΔV exceeds the threshold value
A and is equal to or less than the threshold value B, the
20 second opening and closing device L2 and the first switch
L11 are controlled to be “open”, and the first switch L21
and the second switch L12 are controlled to be “closed”.
The second switch L22 may be controlled to be either “open”
or “closed”.
25 [0045] In the railway vehicle system 100 controlled as
described above, there is formed a charging path from the
storage battery 8B to the storage battery 8A via the third
switch L23, the diode D2, the first switch L21, the second
switch L12, the resistive element R1, and the third switch
30 L13. This enables the storage battery 8A to be charged
with electric power of the storage battery 8B. This
charging path is to be a path passing through one resistive
element R1. Therefore, as compared with the case of FIG.
17
7, two resistance values can be reduced to one resistance
value. This can mitigate a decrease in charging current
with respect to a decrease in the voltage difference ΔV, so
that it is possible to shorten charging time without
5 providing a special current adjustment means.
[0046] The case where the number of storage batteries is
two groups has been described above. Hereinafter, an
operation when the number of storage batteries is three
groups or more will be described.
10 [0047] FIG. 9 is a diagram illustrating a configuration
of a railway vehicle system 100A according to Modification
1 of the embodiment. FIG. 9 illustrates a configuration of
the railway vehicle system 100A in a case where the number
of storage batteries is three groups. In the railway
15 vehicle system 100A illustrated in FIG. 9, a charging
circuit 5C and a storage battery 8C are added to the
configuration of the railway vehicle system 100 illustrated
in FIG. 1. The charging circuit 5C charges the storage
battery 8C. In addition, the charging circuit 5C provides
20 a discharging path when the storage battery 8C discharges.
[0048] The charging circuit 5C includes a first switch
L31, a diode D3 that is a unidirectional element, a second
switch L32, a resistive element R3, a third switch L33, and
a voltage detector 6C. The configuration of the charging
25 circuit 5C is identical to those of the charging circuits
5A and 5B, and a redundant description will be omitted.
[0049] The voltage detector 6C detects a charging
voltage V3 of the storage battery 8C. A detection value of
the charging voltage V3 is also inputted to the control
30 device 3a. The control device 3a controls opening and
closing of the second opening and closing device L2, the
first switches L11, L21, and L31, the second switches L12,
L22, and L32, and the third switches L13, L23, and L33 on
18
the basis of detection values of the charging voltages V1,
V2, and V3.
[0050] Note that, in FIG. 9, the charging circuit 5C
includes the voltage detector 6C, but the configuration is
5 not limited to this. In a case where the storage battery
8C has a voltage detection function, a detection value of
the storage battery 8C may be used. In this case, the
voltage detector 6C can be omitted.
[0051] A configuration other than the above description
10 is identical to or equivalent to the configuration of the
railway vehicle system 100 illustrated in FIG. 1. The
identical or equivalent components are denoted by the same
reference numerals, and a redundant description is omitted.
[0052] Next, an operation of the railway vehicle system
15 100A according to Modification 1 of the embodiment will be
described. Note that a flow of a charging current in the
normal operation and a flow of a discharging current in the
emergency traveling are equivalent to those of the railway
vehicle system 100 having the two-group configuration, and
20 a description thereof is omitted here. Hereinafter, an
operation in imbalance of a charging voltage and an
operation when regenerative power is generated will be
described.
[0053] FIG. 10 is a first diagram to be used for
25 explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100A according to
Modification 1 of the embodiment. In FIG. 10, a maximum
value in the charging voltages V1, V2, and V3 is defined as
Vmax, a minimum value is defined as Vmin, and Vmax=V1 and
30 Vmin=V3 are assumed to be satisfied. Then, for a voltage
difference ΔV=Vmax-Vmin between the maximum value Vmax of
the charging voltage and the minimum value Vmin of the
charging voltage, FIG. 10 illustrates a flow of a charging
19
current when ΔV>B is satisfied.
[0054] In the example of FIG. 10 in which the voltage
difference ΔV exceeds the threshold value B, the second
opening and closing device L2, the first switch L11, and
5 the second switch L22 are controlled to be “open”, and the
second switches L12 and L32 are controlled to be “closed”.
The first switches L21 and L31 may be controlled to be
either “open” or “closed”. That is, the second switch L22
of the charging circuit 5B connected to the storage battery
10 8B having a charging voltage that is neither maximum nor
minimum is controlled to be “open”, the first switch L11 of
the charging circuit 5A connected to the storage battery 8A
having the maximum charging voltage is controlled to be
“open”, the second switch L12 of the charging circuit 5A
15 connected to the storage battery 8A having the maximum
charging voltage is controlled to be “closed”, and the
second switch L32 of the charging circuit 5C connected to
the storage battery 8C having the minimum charging voltage
is controlled to be “closed”.
20 [0055] In the railway vehicle system 100A controlled as
described above, there is formed a charging path from the
storage battery 8A having the maximum charging voltage to
the storage battery 8C having the minimum charging voltage
via the third switch L13, the resistive element R1, the
25 second switch L12, the second switch L32, the resistive
element R3, and the third switch L33. As a result, the
storage battery 8C having the minimum charging voltage can
be charged with electric power of the storage battery 8A
having the maximum charging voltage. Since this charging
30 path is to be a path passing through the two resistive
elements R1 and R3, a charging current can be reduced.
This makes it possible to reduce the charging current
without providing a special current adjustment means. In
20
addition, since charging is performed only between the
storage battery 8A having the maximum charging voltage and
the storage battery 8C having the minimum charging voltage,
charging time can be shortened.
5 [0056] Note that, although FIG. 10 illustrates a case
where the number of storage batteries is three groups, the
present invention is also applicable to a case where the
number of storage batteries is four groups or more. In a
case where the number of storage batteries is four groups
10 or more, when the voltage difference ΔV between the storage
battery having the maximum charging voltage and the storage
battery having the minimum charging voltage has a
relationship of ΔV>B, charging and discharging are
performed between the storage battery having the maximum
15 charging voltage and the storage battery having the minimum
charging voltage.
[0057] FIG. 11 is a second diagram to be used for
explaining an operation in imbalance of a charging voltage
in the railway vehicle system 100A according to
20 Modification 1 of the embodiment. In FIG. 10, charging and
discharging performed between the storage battery having
the maximum charging voltage and the storage battery having
the minimum charging voltage has been described. However,
when the voltage difference ΔV decreases to satisfy a
25 relationship of ΔV≤B, transition is made from a state of
FIG. 10 to a state of FIG. 11. In FIG. 11, the storage
battery having the maximum charging voltage remains as the
storage battery 8A. Whereas, the storage battery having
the maximum charging voltage is shifted from the storage
30 battery 8C to the storage battery 8B. In addition, for the
voltage difference ΔV=Vmax-Vmin between the maximum value
Vmax of the charging voltage and the minimum value Vmin of
the charging voltage, FIG. 11 illustrates a flow of a
21
charging current when a relationship of A<ΔV≤B is
satisfied.
[0058] In the example of FIG. 11, the second opening and
closing device L2 is controlled to be “open”, and the first
5 switches L11 and L31 are controlled to be “closed”. The
first switch L21 and the second switches L12 and L32 may be
controlled to be either “open” or “closed”. That is, the
second switch L22 of the charging circuit 5B connected to
the storage battery 8B having the minimum charging voltage
10 is controlled to be “closed”, and each of the first
switches L11 and L31 in the charging circuits 5A and 5C
connected to the storage batteries 8A and 8C having a nonminimum charging voltage is controlled to be “closed”.
[0059] In the railway vehicle system 100A controlled as
15 described above, there is formed a charging path from the
storage battery 8A having a non-minimum charging voltage to
the storage battery 8B having the minimum charging voltage
via the third switch L13, the diode D1, the first switch
L11, the second switch L22, the resistive element R2, and
20 the third switch L23. In addition, there is formed a
charging path from the storage battery 8C having a nonminimum charging voltage to the storage battery 8B having
the minimum charging voltage via the third switch L33, the
diode D3, the first switch L31, the second switch L22, the
25 resistive element R2, and the third switch L23. As a
result, the storage battery 8B having the minimum charging
voltage can be charged with electric power of the storage
batteries 8A and 8C having non-minimum charging voltages.
In addition, since one storage battery is charged using
30 electric power of the plurality of storage batteries,
charging time can be shortened.
[0060] Next, a charging operation when regenerative
power is generated will be described. FIG. 12 is a diagram
22
to be used for explaining an operation when regenerative
power is generated in a railway vehicle system 100B
according to Modification 2 of the embodiment. In the
railway vehicle system 100B illustrated in FIG. 12, the
5 power conversion device 3 is replaced with a VVVF inverter
31, and the load 4 is replaced with a propulsion motor 41
in the configuration of the railway vehicle system 100A
illustrated in FIG. 9. The VVVF inverter 31 includes an
intermediate link unit 31b. In addition, the control
10 device 3a included in the power conversion device 3 is
replaced with a control device 31a included in the VVVF
inverter 31. The control device 31a has a function of the
control device 3a described above. Note that, other
configuration is identical to or equivalent to the
15 configuration of the railway vehicle system 100A
illustrated in FIG. 9. The identical or equivalent
components are denoted by the same reference numerals, and
a redundant description is omitted.
[0061] The control device 31a monitors an intermediate
20 link voltage V4, which is a voltage of the intermediate
link unit 31b. The control device 31a calculates a voltage
difference ΔE between the intermediate link voltage V4 and
the minimum value Vmin of a charging voltage in the storage
batteries 8A, 8B, and 8C. In a case where the voltage
25 difference ΔE is equal to or less than a threshold value C,
the control device 31a performs charge control on the
storage batteries 8A, 8B, and 8C by using regenerative
power generated by the propulsion motor 41. Note that,
instead of the minimum value Vmin of the charging voltage,
30 an average value of the charging voltage in the storage
batteries 8A, 8B, and 8C may be used. In addition, in the
following description, the threshold value C may be
referred to as a “third threshold value”.
23
[0062] In a case where the voltage difference ΔE is
equal to or less than the threshold value C, the second
opening and closing device L2 and the second switches L12,
L22, and L32 are controlled to be “closed”. The first
5 switches L11, L21, and L31 may be controlled to be either
“open” or “closed”.
[0063] In the railway vehicle system 100B controlled as
described above, there is formed a charging path from the
propulsion motor 41 to the storage battery 8A via the VVVF
10 inverter 31, the second opening and closing device L2, the
second switch L12, the resistive element R1, and the third
switch L13. In addition, there is formed a charging path
from the propulsion motor 41 to the storage battery 8B via
the VVVF inverter 31, the second opening and closing device
15 L2, the second switch L22, the resistive element R2, and
the third switch L23. In addition, there is formed a
charging path from the propulsion motor 41 to the storage
battery 8C via the VVVF inverter 31, the second opening and
closing device L2, the second switch L32, the resistive
20 element R3, and the third switch L33. This allows the
storage batteries 8A, 8B, and 8C to be charged using the
regenerative power, so that the regenerative power can be
effectively used.
[0064] Next, a connection form between a VVVF inverter
25 and an auxiliary power supply device will be described.
FIG. 13 is a diagram illustrating a configuration of a
railway vehicle system 100C according to Modification 3 of
the embodiment. In the railway vehicle system 100C
illustrated in FIG. 13, an auxiliary power supply device 32
30 and an auxiliary machine 42 connected to the auxiliary
power supply device 32 are added to the configuration of
the railway vehicle system 100B illustrated in FIG. 12.
The VVVF inverter 31 is connected to electric wiring 15
24
that connects the first opening and closing device L1 and
the second opening and closing device L2 via an opening and
closing device L3. The auxiliary power supply device 32 is
connected to the electric wiring 15 via an opening and
5 closing device L4.
[0065] FIG. 13 illustrates a configuration in which the
VVVF inverter 31 and the auxiliary power supply device 32
are connected to the overhead wire 1 and the storage
batteries 8A, 8B, and 8C in an equal manner, but the
10 configuration is not limited to this. For example, the
configuration may be as illustrated in FIG. 14. FIG. 14 is
a diagram illustrating a configuration of a railway vehicle
system 100D according to Modification 4 of the embodiment.
In the railway vehicle system 100D illustrated in FIG. 14,
15 an opening and closing device L5 is provided between the
first opening and closing device L1 and the second opening
and closing device L2. The VVVF inverter 31 is connected
to electric wiring 15a that connects the first opening and
closing device L1 and the opening and closing device L5.
20 The auxiliary power supply device 32 is connected to
electric wiring 15b that connects the second opening and
closing device L2 and the opening and closing device L5.
Note that a configuration may be adopted in which the
relationship between the VVVF inverter 31 and the auxiliary
25 power supply device 32 are exchanged, and the auxiliary
power supply device 32 is arranged on the overhead wire 1
side. In any case, any configuration may be adopted as
long as electric power of the overhead wire 1 is supplied
to both the VVVF inverter 31 and the auxiliary power supply
30 device 32, and electric power of the storage batteries 8A,
8B, and 8C is supplied to both the VVVF inverter 31 and the
auxiliary power supply device 32.
[0066] Note that, although FIG. 12 illustrates the
25
configuration in which the control device 31a included in
the VVVF inverter 31 controls the second opening and
closing device L2 and the charging circuits 5A, 5B, and 5C,
the configuration is not limited to this. A configuration
5 may be adopted in which the second opening and closing
device L2 and the charging circuits 5A, 5B, and 5C are
controlled by a control device (not illustrated) included
in the auxiliary power supply device 32.
[0067] As described above, the railway vehicle system
10 according to the embodiment includes: a power conversion
device that converts electric power supplied from an
overhead wire into AC power to a load; a plurality of
storage batteries that supply emergency electric power for
use in a railway vehicle, to the power conversion device;
15 and charging circuits that charge the storage batteries.
Further, the railway vehicle system includes: a first
opening and closing device that opens and closes an
electrical connection between the overhead wire and the
power conversion device; and a second opening and closing
20 device that opens and closes an electrical connection
between each of the charging circuits and the overhead wire
and an electrical connection between each of the charging
circuits and the power conversion device. The power
conversion device includes a control device that controls
25 opening and closing of the second opening and closing
device and the charging circuits on the basis of
information on a charging voltage of the plurality of
storage batteries. The control device controls the opening
and closing device of the second opening and closing device
30 to be closed to cause a current supplied from the overhead
wire to flow to the storage battery, and the charging
circuit performs floating charge of the storage battery
with a current supplied from the overhead wire. As a
26
result, since the plurality of storage batteries can be
charged without using a converter device, it is possible to
prevent an increase in size of the system and an increase
in manufacturing cost.
5 [0068] In addition, when imbalance of a charging voltage
occurs between the plurality of storage batteries during
floating charge of the plurality of storage batteries, the
control device controls the second opening and closing
device to be open so as to enable charging and discharging
10 between the individual storage batteries. Furthermore, the
control device controls the first and second switches of
each charging circuit to be closed. As a result, even
during operation of the railway vehicle system, imbalance
of a charging voltage between the plurality of storage
15 batteries can be resolved.
[0069] Further, when electric power supply from the
overhead wire is interrupted and electric power of each
storage battery is supplied to the power conversion device,
the control device controls the second opening and closing
20 device to be closed and controls the first switch of each
charging circuit to be closed. As a result, each storage
battery can be caused to perform a discharging operation,
and emergency electric power held in the plurality of
storage batteries can be supplied to the power conversion
25 device.
[0070] Note that, in a charging voltage of the plurality
of storage batteries, when a difference between a maximum
value of the charging voltage and a minimum value of the
charging voltage decreases to the first threshold value or
30 less, the control device controls the second opening and
closing device to be closed and restarts the floating
charge. By doing in this way, it is possible to cope with
a trouble of an overhead wire or the like while allowing a
27
difference in charging voltage between the plurality of
storage batteries.
[0071] Further, when a difference between a maximum
value of the charging voltage and a minimum value of the
5 charging voltage exceeds the second threshold value, which
is larger than the first threshold value, the control
device controls the second opening and closing device to be
open, and controls the second switch of the charging
circuit connected to each storage battery having a charging
10 voltage that is neither maximum nor minimum to be open.
Further, the control device controls the first switch of
the charging circuit connected to the storage battery
having the maximum charging voltage to be open. Further,
the control device controls, to be closed, the second
15 switch of each of a charging circuit connected to the
storage battery having the maximum charging voltage and a
charging circuit connected to the storage battery having
the minimum charging voltage. As a result, charging and
discharging can be performed between the storage battery
20 having the maximum charging voltage and the storage battery
having the minimum charging voltage. Further, when a
difference between a maximum value of the charging voltage
and a minimum value of the charging voltage decreases to
the second threshold value or less, the first and second
25 switches of all the charging circuits are controlled to be
closed. This enables mutual charging between the
individual storage batteries. The above control makes it
possible to efficiently resolve imbalance of a charging
voltage between the plurality of storage batteries.
30 [0072] Further, in a case where the propulsion motor
generates regenerative electric power, when a difference
between an intermediate link voltage of the VVVF inverter
and a minimum value of a charging voltage of the plurality
28
of storage batteries or an average value of a charging
voltage of the plurality of storage batteries is equal to
or less than the third threshold value, the control device
controls the second switch of each charging circuit to be
5 closed so as to enable charging with the regenerative
power. As a result, the regenerative power can be
effectively used.
[0073] Next, a hardware configuration for implementing
the functions of the control device 3a in the embodiment
10 will be described with reference to the drawings of FIGS.
15 and 16. FIG. 15 is a block diagram illustrating an
example of a hardware configuration that implements the
functions of the control device 3a according to the
embodiment. FIG. 16 is a block diagram illustrating
15 another example of a hardware configuration that implements
the functions of the control device 3a according to the
embodiment.
[0074] In a case where some or all of the functions of
the control device 3a in the embodiment are implemented, as
20 illustrated in FIG. 15, a configuration may be adopted
including a processor 200 that performs arithmetic
operation, a memory 202 that stores a program to be read by
the processor 200, and an interface 204 that inputs and
outputs signals.
25 [0075] The processor 200 may be an arithmetic means such
as an arithmetic device, a microprocessor, a microcomputer,
a central processing unit (CPU), or a digital signal
processor (DSP). Further, examples of the memory 202 can
include a nonvolatile or volatile semiconductor memory such
30 as a random access memory (RAM), a read only memory (ROM),
a flash memory, an erasable programmable ROM (EPROM), or an
electrically EPROM (EEPROM, registered trademark), a
magnetic disk, a flexible disk, an optical disk, a compact
29
disk, a mini disk, and a digital versatile disc (DVD).
[0076] The memory 202 stores a program for executing the
functions of the control device 3a in the embodiment. The
processor 200 can perform the above-described processing by
5 exchanging necessary information via the interface 204,
causing the processor 200 to execute a program stored in
the memory 202, and causing the processor 200 to refer to a
table stored in the memory 202. An operation result by the
processor 200 can be stored in the memory 202.
10 [0077] In addition, in a case where some of the
functions of the control device 3a in the embodiment are
implemented, processing circuitry 203 illustrated in FIG.
16 can also be used. The processing circuitry 203
corresponds to a single circuit, a composite circuit, an
15 application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA), or a combination of these.
Information inputted to the processing circuitry 203 and
information outputted from the processing circuitry 203 can
be obtained via the interface 204.
20 [0078] Note that some of the processing in the control
device 3a may be performed by the processing circuitry 203,
and processing that is not performed by the processing
circuitry 203 may be performed by the processor 200 and the
memory 202.
25 [0079] Note that the configuration illustrated in the
above embodiment illustrates one example of the contents of
the present invention and can be combined with another
known technique, and it is also possible to omit and change
a part of the configuration without departing from the
30 subject matter of the present invention.
Reference Signs List
[0080] 1 overhead wire; 2 current collection device; 3
30
power conversion device; 3a, 31a control device; 4 load;
5A, 5B, 5C charging circuit; 6A, 6B, 6C voltage detector;
8A, 8B, 8C storage battery; 15, 15a, 15b electric wiring;
31 VVVF inverter; 31b intermediate link unit; 32
5 auxiliary power supply device; 41 propulsion motor; 42
auxiliary machine; 100, 100A, 100B, 100C, 100D railway
vehicle system; 150 railway vehicle; 200 processor; 202
memory; 203 processing circuitry; 204 interface; D1, D2,
D3 diode; L1 first opening and closing device; L2 second
10 opening and closing device; L3, L4, L5 opening and closing
device; L11, L21, L31 first switch; L12, L22, L32 second
switch; L13, L23, L33 third switch; R1, R2, R3 resistive
element.
31
We Claim :
1. A railway vehicle system comprising:
a power conversion device to convert electric power
supplied from an overhead wire into alternating-current
5 power to a load;
a plurality of storage batteries to supply emergency
electric power for use in a railway vehicle, to the power
conversion device;
charging circuits to charge the storage batteries;
10 a first opening and closing device to open and close
an electrical connection between the overhead wire and the
power conversion device; and
a second opening and closing device to open and close
an electrical connection between each of the charging
15 circuits and the overhead wire and an electrical connection
between each of the charging circuits and the power
conversion device, wherein
the power conversion device includes a control device
to control opening and closing of the second opening and
20 closing device and the charging circuits, based on
information on a charging voltage of a plurality of the
storage batteries,
the control device controls the second opening and
closing device to be closed to cause a current supplied
25 from the overhead wire to flow to the storage batteries via
the charging circuits, and
the charging circuits perform floating charge of the
storage batteries with a current supplied from the overhead
wire.
30
2. The railway vehicle system according to claim 1,
wherein
each of the charging circuits includes first and
32
second circuits connected in parallel to each other, and
the first circuit is a circuit in which a first switch
is connected in series with a unidirectional element
connected in a direction in which a charging current to the
5 storage batteries is blocked, and
the second circuit is a circuit in which a second
switch and a resistor are connected in series.
3. The railway vehicle system according to claim 2,
10 wherein
the control device controls the second opening and
closing device to be closed and controls the second switch
of each of the charging circuits to be closed to enable
floating charge of each of the storage batteries.
15
4. The railway vehicle system according to claim 2,
wherein
the control device controls the second opening and
closing device to be open and controls the first and second
20 switches of each of the charging circuits to be closed to
enable charging and discharging between each of the storage
batteries.
5. The railway vehicle system according to claim 3 or 4,
25 wherein
when electric power supply from the overhead wire is
interrupted and electric power of each of the storage
batteries is supplied to the power conversion device,
the control device controls the second opening and
30 closing device to be closed and controls the first switch
of each of the charging circuits to be closed to cause a
discharge operation of each of the storage batteries.
33
6. The railway vehicle system according to any one of
claims 3 to 5, wherein
in a charging voltage of a plurality of the storage
batteries, when a difference between a maximum value of the
5 charging voltage and a minimum value of the charging
voltage decreases to a first threshold value or less,
the control device controls the second opening and
closing device to be closed to restart the floating charge.
10 7. The railway vehicle system according to claim 6,
wherein
when a difference between a maximum value of the
charging voltage and a minimum value of the charging
voltage exceeds a second threshold value that is larger
15 than the first threshold value,
the control device controls the second opening and
closing device to be open, controls the second switch of a
charging circuit connected to each storage battery having
the charging voltage that is neither maximum nor minimum to
20 be open, controls the first switch of a charging circuit
connected to a storage battery having the charging voltage
that is maximum to be open, and controls, to be closed, the
second switch in each of a charging circuit connected to a
storage battery having the charging voltage that is maximum
25 and a charging circuit connected to a storage battery
having the charging voltage that is minimum, to cause
charging and discharging to be performed between the
storage battery having the charging voltage that is maximum
and the storage battery having the charging voltage that is
30 minimum.
8. The railway vehicle system according to claim 7,
wherein
34
when a difference between a maximum value of the
charging voltage and a minimum value of the charging
voltage decreases to the second threshold value or less,
the control device controls the first and second
5 switches of all charging circuits to be closed to enable
mutual charging between each of the storage batteries.
9. The railway vehicle system according to any one of
claims 2 to 8, wherein
10 the power conversion device is a variable voltage
variable frequency inverter to supply electric power to a
propulsion motor that is for railway vehicle driving, and
the control device is a control device to control an
operation of the variable voltage variable frequency
15 inverter.
10. The railway vehicle system according to claim 9,
wherein
in a case where the propulsion motor generates
20 regenerative power, and a difference between an
intermediate link voltage of the variable voltage variable
frequency inverter and a minimum value of a charging
voltage of a plurality of the storage batteries or an
average value of a charging voltage of a plurality of the
25 storage batteries is equal to or less than a third
threshold value,
the control device controls the second switch of each
of the charging circuits to be closed to enable charging
with the regenerative power.
30
11. The railway vehicle system according to any one of
claims 1 to 8, wherein
the power conversion device includes an auxiliary
35
power supply device to supply electric power to an
auxiliary device, and
the control device is a control device to control an
operation of the auxiliary power supply device.