FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
CONTROL DEVICE FOR RAILWAY VEHICLES;
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 Technical Field
[0001] The present disclosure relates to a railway vehicle control device.
Background Art
[0002] A current collector, such as a pantograph and a current collecting shoe, that
is mounted on an electric railway vehicle, acquires power by touching a power supply
10 line such as an overhead line and a third rail. A power conversion system mounted on
the electric railway vehicle converts the power acquired by the current collector into
alternating current (AC) power and supplies the AC power to an AC motor. Driving of
the AC motor by receiving the supply of the AC power results in propulsion of the
electric railway vehicle. Also, at the time of braking, the power conversion system
15 converts, into direct current (DC) power, the power supplied from the AC motor
operating as a generator and supplies the DC power to a power conversion system
mounted on another electric railway vehicle via the power supply line. An example of
such a power conversion system is disclosed in Patent Literature 1. A power conversion
system disclosed in Patent Literature 1 includes an inverter device as a power converter,
20 and includes an inverter controller as a controller that controls the power converter. The
power converter converts power supplied from a current collector connected to a primary
terminal and supplies the converted power to an electric motor connected to a secondary
terminal. On the other hand, at the time of braking, the power converter converts AC
power supplied from the electric motor into DC power. Also, during braking, by
25 causing operation of a chopper device provided on the current-collector side of the power
converter, a voltage on the current-collector side of the power converter is adjusted to a
range suitable for supplying power to a power conversion system mounted on another
3
electric railway vehicle.
Citation List
Patent Literature
[0003] Patent Literature 1: Unexamined Japanese Patent Application Publication
5 No. 2004-236397
Summary of Invention
Technical Problem
[0004] The power converter is stopped in cases such as when an emergency brake
is applied while the electric railway vehicle is running or when the power converter needs
10 to be protected due to detection of an overvoltage or an overcurrent of the power
converter or the like. Also, opening a contactor provided between the current collector
and the power converter to electrically disconnect the power converter from the current
collector after stopping the power converter is conceivable. In the power conversion
system disclosed in Patent Literature 1, when the power converter is stopped and the
15 contactor is opened, even after the power converter is stopped, an electrical current may
continue to flow from the current collector toward the power converter due to delay of
mechanical operation. As a result, an overvoltage may occur on the primary side of the
power converter.
[0005] In consideration of such circumstances, an object of the present disclosure is
20 to provide a railway vehicle control device enabling suppression of an overvoltage
occurring on the primary side of a power converter.
Solution to Problem
[0006] In order to attain the aforementioned objective, a railway vehicle control
device according to the present disclosure includes a torque controller and a circuit
25 controller. The torque controller controls operation of switching elements included in a
power converter so as to adjusts a torque of an electric motor, the power converter having
a primary side to which a power supply is connected and a secondary side to which the
4
electric motor is connected and being configured to perform bidirectional power
conversion between the primary side and the secondary side. The circuit controller
acquires a voltage on the primary side of the power converter and, when the voltage on
the primary side is equal to or higher than a reference voltage, causes operation of a
5 step-down circuit connected in parallel to the primary side. Upon acquiring a stop
command that is an instruction to turn off the switching elements of the power converter,
the torque controller stops the operation of the switching elements of the power converter.
Upon acquiring the stop command, the circuit controller causes operation of the
step-down circuit.
10 Advantageous Effects of Invention
[0007] According to the present disclosure, upon acquiring the stop command, the
railway vehicle control device causes operation of the step-down circuit. Accordingly,
the overvoltage on the primary side of the power converter can be suppressed.
Brief Description of Drawings
15 [0008] FIG. 1 is a block diagram illustrating a configuration of a power conversion
system for a railway vehicle according to an embodiment of the present disclosure;
FIG. 2 is a block diagram illustrating a configuration of a railway vehicle control
device according to the embodiment;
FIG. 3 is a graph illustrating an example of a duty ratio of a chopper circuit
20 according to the embodiment;
FIG. 4 is a flow chart illustrating one example of overvoltage suppression
operation performed by the railway vehicle control device according to the embodiment;
and
FIG. 5 is a diagram illustrating an example of a hardware configuration of the
25 railway vehicle control device according to the embodiment.
Description of Embodiments
[0009] A railway vehicle control device according to an embodiment of the present
5
disclosure is described below in detail with reference to drawings. Components that are
the same or equivalent are assigned the same reference signs throughout the drawings.
[0010] A power conversion system 1 for a railway vehicle (hereinafter referred to as
a power conversion system) according to an embodiment of the present disclosure
5 illustrated in FIG. 1 is mounted on an electric railway vehicle. An operation command
is input to the power conversion system 1 from a cab of the electric railway vehicle.
The operation command includes a power running command that is an instruction to
accelerate the electric railway vehicle or a brake command that is an instruction to
decelerate the electric railway vehicle. When the operation command includes the
10 power running command, that is, at the time of power running, the power conversion
system 1 acquires direct current (DC) power from a non-illustrated substation that is an
example of a DC power supply via an overhead line 2 that is an example of a power
supply line. Additionally, the power conversion system 1 converts the DC power into
alternating current (AC) power and supplies the AC power to an electric motor 8, thereby
15 driving the electric motor 8. Driving of the electric motor 8 results in propulsion of the
electric railway vehicle. When the operation command includes the brake command,
that is, at the time of braking, the power conversion system 1 converts, into DC power,
power generated by the electric motor 8 operating as a generator, and supplies, via the
overhead line 2, the DC power to another power conversion system 1 mounted on
20 another electric railway vehicle.
[0011] The power conversion system 1 includes (i) a pantograph 3 that is an
example of a power collector and acquires DC power from the substation via the
overhead line 2, and (ii) a power converter 12 that converts the DC power into AC power
and supplies the AC power to the electric motor 8. Also, the power conversion system 1
25 includes a railway vehicle control device 20 (hereinafter referred to as a control device)
that controls the power converter 12 and controls contactors 4 and 5 that switch electrical
connection between the pantograph 3 and the power converter 12. Additionally, the
6
control device 20 causes operation of a chopper circuit 14 in addition to the
above-described control. The chopper circuit 14 is provided as an example of a
step-down circuit and is connected on the pantograph 3-side of the power converter 12 in
parallel to the pantograph 3. Specifically, the chopper circuit 14 includes a switching
5 element 15 and a brake resistor 16 that are connected to each other in series. The
control device 20 increases a duty ratio of the switching element 15 included in the
chopper circuit 14. As a result, power output by the power converter 12 is consumed by
the chopper circuit 14, and a voltage of a filter capacitor 11 connected to the primary side
of the power converter 12 is reduced. The power conversion system 1 further includes
10 (i) a voltage detector 13 that detects a voltage EFC of the filter capacitor 11 and (ii) a
current detector 9 that detects each of U-phase, V-phase, and W-phase currents flowing to
the electric motor 8.
[0012] When the electric railway vehicle starts running, the pantograph 3 rises in
accordance with operation in the cab and comes into contact with the overhead line 2.
15 Thereafter, in the state in which the contactor 4 is opened, the control device 20 closes the
contactor 5. A resistor 6 is connected to the contactor 5 in series, and power is supplied
from the pantograph 3 to the power converter 12 via the contactor 5 and the resistor 6,
thereby suppressing a flow of an inrush current through the power converter 12.
Thereafter, when the voltage EFC of the filter capacitor 11 reaches an input voltage
20 serving as a reference, the control device 20 closes the contactor 4 and opens the
contactor 5.
[0013] After the start of running of the electric railway vehicle, the control device
20 performs later-described control based on an operation command signal S1 and a stop
command signal S2. The operation command signal S1 is a signal depending on
25 operation of a master controller in the cab and indicates a power running notch or a brake
notch. Also, the stop command signal S2 is assumed to be input from an abnormality
detection device that detects an abnormality of the electric railway vehicle. The stop
7
command signal S2 (i) becomes an High (H) level when instructing to turn off switching
elements of the power converter 12 and (ii) becomes an L (Low) level when instructing to
maintain switching operation of the power converter 12. The abnormality detection
device detects various types of abnormalities such as an overvoltage and an overcurrent
5 of the power converter 12, an overcurrent of the electric motor 8, and a state in which the
pantograph 3 is separated from the overhead line 2.
[0014] When the operation command signal S1 indicates the power running notch
and the stop command signal S2 is at the L level, the control device 20 switches on and
off the switching elements of the power converter 12 so that the power converter 12
10 converts, into AC power, DC power supplied from the pantograph 3 via the contactor 4
and a smoothing reactor 7. The power converter 12 supplies the AC power to the
electric motor 8 connected to the secondary side. Specifically, the control device 20 (i)
calculates a target torque for obtaining a target acceleration indicated by the power
running notch and (ii) also calculates an actual torque of the electric motor 8 from
15 currents flowing to the electric motor 8. Additionally, the control device 20 controls
operation of the switching elements of the power converter 12 in order to bring the actual
torque closer to the target torque. Also, a three-phase induction motor is used as the
electric motor 8, and the control device 20 acquires value of the currents flowing to the
electric motor 8 from the current detector 9 that detects the U-phase, V-phase, and
20 W-phase currents flowing to the electric motor 8.
[0015] On the other hand, when the operation command signal S1 indicates the
brake notch, and the stop command signal S2 is at the L level, the control device 20
controls the operation of the switching elements of the power converter 12 in order for
the power converter 12 to convert, into DC power, regenerative power generated by the
25 electric motor 8 that operates as a generator. The DC power is supplied to the other
power conversion system 1 mounted on the other electric railway vehicle via the
overhead line 2. In order to supply power to the other power conversion system 1
8
mounted on the other electric railway vehicle via the overhead line 2, the voltage EFC of
the filter capacitor 11 needs to be higher than an overhead line voltage. However, if the
voltage EFC is excessively higher than the voltage of the overhead line, an overvoltage
occurs on the overhead line. Accordingly, the voltage EFC needs to be maintained in a
5 range suitable for supplying power to the other power conversion system 1 mounted on
the other electric railway vehicle. Thus, the control device 20 causes operation of the
chopper circuit 14 when the voltage EFC is equal to or higher than a reference voltage.
The chopper circuit 14 includes the switching element 15 and the brake resistor 16 that
are connected to each other in series. When the switching element 15 is turned on by
10 the control device 20, power supplied from the filter capacitor 11 is consumed by the
brake resistor 16, and the voltage EFC decreases. Specifically, the control device 20
adjusts the duty ratio of the switching element 15 based on a duty ratio that is positively
correlated with the voltage EFC and varies with time in response to a time variation in the
voltage EFC.
15 [0016] Additionally, when the operation command signal S1 indicates the power
running notch and the stop command signal S2 is at the H level, the control device 20
causes operation of the chopper circuit 14 independently of the magnitude relationship
between the voltage EFC and the reference voltage. In other words, when the operation
command signal S1 indicates the power running notch, and the stop command signal S2
20 reaches the H level, even if the voltage EFC is less than the reference voltage, the control
device 20 increases the duty ratio of the switching element 15 of the chopper circuit 14
such that the duty ratio of the switching element 15 is greater than zero.
[0017] As illustrated in FIG. 2, the control device 20 includes (i) a torque controller
21 that switches on and off the switching elements included in the power converter 12,
25 (ii) a contactor controller 22 that closes or opens the contactors 4 and 5, (iii) a circuit
controller 23 that causes operation of the chopper circuit 14, and (iv) a target calculator
24 that calculates a target torque of the electric motor 8. Summaries of each component
9
of the control device 20 are described as follows. The target calculator 24 (i) calculates
the target torque of the electric motor 8 that is required to obtain a target acceleration
indicated by the power running notch or a target deceleration indicated by the brake
command and (ii) sends the target torque to the torque controller 21. The torque
5 controller 21 calculates the actual torque or a regenerative torque of the electric motor 8
from phase currents detected by the current detector 9. Additionally, the torque
controller 21 controls the operation of the switching elements of the power converter 12
so that the actual torque or the regenerative torque approaches the target torque. Also,
when the operation command signal S1 indicates the power running notch, and the stop
10 command signal S2 reaches the H level, the torque controller 21 turns off the switching
elements of the power converter 12. The circuit controller 23 acquires the voltage EFC
of the filter capacitor 11 from the voltage detector 13 and, when the voltage EFC is equal
to or higher than the reference voltage, the circuit controller 23 causes operation of the
chopper circuit 14 by adjusting the duty ratio of the switching element 15 of the chopper
15 circuit 14 based on the duty ratio that is positively correlated with the voltage EFC.
When the operation command signal S1 indicates the power running notch, and the stop
command signal S2 reaches the H level, the circuit controller 23 switches on and off the
switching element 15 of the chopper circuit 14 based on the duty ratio that is positively
correlated with the voltage EFC independently of the magnitude relationship between the
20 voltage EFC and the reference voltage, thereby causing operation of the chopper circuit
14. Also, the circuit controller 23 can set a limit on a time period during which the
chopper circuit 14 is operated.
[0018] The details of each component of the control device 20 are described below.
The torque controller 21 switches on and off the switching elements included in the
25 power converter 12 in accordance with the operation command signal S1 and the stop
command signal S2. Specifically, when the operation command signal S1 indicates the
power running notch, and the stop command signal S2 is at the L level, the torque
1 0
controller 21 controls the operation of the switching elements of the power converter 12
to bring the actual torque close to the target torque. Also, when the operation command
signal S1 includes the brake command, and the stop command signal S2 is at the L level,
the torque controller 21 controls the operation of the switching elements of the power
5 converter 12 to bring the regenerative torque close to the target torque. Also, when the
stop command signal S2 reaches the H level, the torque controller 21 turns off the
switching elements of the power converter 12.
[0019] When the electric railway vehicle starts running, in the state in which the
contactor 4 is opened, the contactor controller 22 closes the contactor 5. Thereafter, the
10 contactor controller 22 closes the contactor 4 and then opens the contactor 5. That is,
during the running of the electric railway vehicle, the contactor 4 is closed and the
contactor 5 is opened. When the stop command signal S2 reaches the H level during the
running of the electric railway vehicle, the contactor controller 22 opens the contactor 4.
Thereafter, closing operation of the contactors 4 and 5 is the same as when the electric
15 railway vehicle starts running.
[0020] When the operation command signal S1 indicates the brake notch, and the
stop command signal S2 is at the L level, the circuit controller 23 adjusts the duty ratio of
the switching element 15 of the chopper circuit 14 based on the duty ratio that is
positively correlated with the voltage EFC of the filter capacitor 11 detected by the
20 voltage detector 13 and varies with time in response to a time variation in the voltage
EFC. Specifically, when the voltage EFC of the filter capacitor 11 becomes equal to or
higher than the reference voltage E1, the duty ratio of the switching element 15 included
in the chopper circuit 14 is adjusted based on the above-described duty ratio. An
example of the duty ratio that is positively correlated with the voltage EFC is illustrated
25 by a thick solid line in FIG. 3. The duty ratio indicated by the thick solid line in FIG. 3
increases from a minimum duty ratio RMIN to a maximum duty ratio RMAX with increase
of the voltage EFC. Also, the duty ratio in a case in which the voltage EFC is equal to
1 1
or less than the reference voltage E1 is defined as the minimum duty ratio RMIN. Also,
the duty ratio in a case in which the voltage EFC is equal to or higher than a voltage E2 is
defined as the maximum duty ratio RMAX. As described above, the length of the on-time
with respect to a period of the switching element 15 increases with an increase of the
5 voltage EFC. As a result, power flowing from the filter capacitor 11 to the brake
resistor 16 and consumed by the brake resistor 16 increases, and the overvoltage of the
filter capacitor 11 is suppressed.
[0021] The timings with which the circuit controller 23 causes operation of the
chopper circuit 14 are not limited to those of the above-described case in which the
10 operation command signal S1 indicates the brake notch. When the operation
command signal S1 indicates the power running notch, and the stop command signal S2
is at the H level, the circuit controller 23 adjusts the duty ratio of the switching element
15 of the chopper circuit 14 independently of the magnitude relationship between the
voltage EFC of the filter capacitor 11 and the reference voltage E1 and based on the duty
15 ratio that is positively correlated with the voltage EFC and varies with time in response to
a time variation in the voltage EFC. In other words, when the operation command
signal S1 indicates the power running notch, and the stop command signal S2 is at the H
level, even if the voltage EFC is less than the reference voltage E1, the circuit controller
23 adjusts the duty ratio of the switching element 15 based on the duty ratio that is
20 positively correlated with the voltage EFC. FIG. 3 illustrates by a thin solid line, in the
case in which the operation command signal S1 indicates the power running notch, and
the stop command signal S2 is at the H level, an example of the duty ratio that is
positively correlated with the voltage EFC. The duty ratio indicated by the thin solid
line in FIG. 3 increases from the minimum duty ratio RMIN to a maximum duty ratio
25 R'MAX with increase of the voltage EFC.
[0022] In FIG. 3, the duty ratio is taken to be R1 in a case in which (i) the operation
command signal S1 indicates the power running notch, (ii) the stop command signal S2 is
1 2
at the H level, and (iii) the voltage EFC matches the reference voltage E1. Also, the
duty ratio in the case in which the operation command signal S1 indicates the brake notch,
and the voltage EFC matches the reference voltage E1, is the minimum duty ratio RMIN as
described above. The duty ratio in the case in which the operation command signal S1
5 indicates the power running notch, and the stop command signal S2 is at the H level, is
determined such that R1 > the minimum duty ratio RMIN. The duty ratio in the case in
which the operation command signal S1 indicates the power running notch, and the stop
command signal S2 is at the H level, is determined as described above, thereby enabling
quick reduction of the voltage EFC upon acquisition of the stop command signal S2.
10 [0023] Also, as illustrated in FIG. 3, the maximum duty ratio R'MAX, in the case in
which the operation command signal S1 indicates the power running notch and the stop
command signal S2 is at the H level, is set to be sufficiently less than the maximum duty
ratio RMAX, in a case in which the operation command signal S1 indicates the brake notch
and the command signal S2 is at the L level. In a case in which the maximum duty ratio
15 R'MAX is assumed to be as great as the maximum duty ratio RMAX, during a period from a
time when the switching elements of the power converter 12 is turned off to a time when
the contactor 4 is opened, power that the pantograph 3 acquires from the substation via
the overhead line 2 is sometimes supplied to the chopper circuit 14 and consumed by the
brake resistor 16. Accordingly, the maximum duty ratio R'MAX is set to be a value
20 sufficiently less than the maximum duty ratio RMAX, thereby suppressing the
consumption in the chopper circuit 14 of the power acquired by the pantograph 3.
[0024] The operation of overvoltage suppression processing performed by the
control device 20 having the above-described configuration is described with reference to
FIG. 4. When the electric railway vehicle starts running, the control device 20 starts the
25 overvoltage suppression processing illustrated in FIG. 4. When the operation command
signal S1 indicates the brake notch, that is, when the operation command signal S1 does
not indicate the power running notch (No in step S11), the circuit controller 23 compares
1 3
the voltage EFC of the filter capacitor 11 with the reference voltage E1 (step S12).
When the voltage EFC is less than the reference voltage E1 (No in step S12), the
processes of steps S11 and S12 are repeated. When the operation command signal S1
indicates the brake notch (No in step S11), and the voltage EFC is equal to or greater than
5 the reference voltage E1 (Yes in step S12), the circuit controller 23 adjusts the duty ratio
of the switching element 15 of the chopper circuit 14 based on the duty ratio that is
positively correlated with the voltage EFC and varies with time in response to a time
variation in the voltage EFC (step S13). Upon completion of the process in step S13,
the processing returns to step S12, and the voltage EFC is compared with the reference
10 voltage E1.
[0025] Also, when the operation command signal S1 indicates the power running
notch (Yes in step S11), and the stop command signal S2 is at the L level (No in step S14),
the processes of steps S11 and S14 are repeated. When the operation command signal
S1 indicates the power running notch (Yes in step S11), and the stop command signal S2
15 is at the H level (Yes in step S14), the processes of steps S15, S16, and S17 described
later are performed in parallel. Specifically, the torque controller 21 turns off the
switching elements of the power converter 12 (step S15). Also, the contactor controller
22 opens the contactor 4 (step S16). Also, the circuit controller 23 adjusts the duty ratio
of the switching element 15 of the chopper circuit 14 (step S17). Specifically, in step
20 S17, the circuit controller 23 switches on and off the switching element 15 of the chopper
circuit 14 based on the duty ratio that is positively correlated with the voltage EFC. If
an operation time based on the minimum duty ratio is less than a predetermined time (No
in step S18), the process of step S17 is repeated. Specifically, the circuit controller 23 (i)
includes a time measurement circuit, (ii) measures a period during which the duty ratio is
25 set to the minimum duty ratio, and (iii) determines whether the measured period is equal
to or longer than a predetermined period. When the chopper circuit 14 operates for the
predetermined period or more based on the minimum duty ratio (Yes in step S18), the
1 4
circuit controller 23 stops the chopper circuit 14 (step S19). Specifically, in step S19,
the circuit controller 23 turns off the switching element 15 of the chopper circuit 14.
When the processes in steps S15, S16, and S19 are completed, the control device 20 ends
the overvoltage suppression processing. Thereafter, as described above, when (i) the
5 contactor 5 is opened after the contactor 5 and the contactor 4 are closed in that order and
then (ii) an operation command is input, the control device 20 starts the process of step
S11 again.
[0026] As described above, according to the control device 20 according to the
embodiment, upon acquiring the stop command, the chopper circuit 14 is operated
10 independently of the magnitude relationship between the voltage EFC and the reference
voltage, thereby enabling suppression of the overvoltage of the filter capacitor 11.
[0027] FIG. 5 is a diagram illustrating an example of a hardware configuration of
the railway vehicle control device according to the embodiment. As a hardware
configuration for controlling the respective components, the railway vehicle control
15 device 20 includes a processor 31, a memory 32, and an interface 33. Each function of
these components is achieved by the processor 31 executing a program stored in the
memory 32. The interface 33 serves as an element that connects these components and
that establishes communication, and the railway vehicle control device 20 may include a
plurality of types of interfaces as necessary. Although FIG. 5 illustrates an example in
20 which the railway vehicle control device 20 includes one processor 31 and one memory
32, a plurality of processors 31 and a plurality of memories 32 may execute the respective
functions in cooperation with one another.
[0028] Additionally, the above-described hardware configuration and flowchart are
merely examples and can be freely changed or modified.
25 [0029] The central portion that includes the processor 31, the memory 32, and the
interface 33 to perform control processing can be achieved using a normal computer
system without using a dedicated system. For example, the railway vehicle control
1 5
device 20 may be configured to execute the above-described processes by (i) storing, on a
computer readable recording medium (a flexible disc, a compact disc-read only memory
(CD-ROM), digital versatile disc-read only memory (DVD-ROM) or the like, a computer
program for executing the above-described processes, (ii) distributing the medium, and
5 (iii) installing the computer program in a computer. Alternatively, the railway vehicle
control device 20 may be configured by (i) storing the above-described computer
program in a storage device that is included in a server device on a communication
network and (ii) downloading the computer program onto a normal computer system.
[0030] Also, when the functions of the railway vehicle control device 20 are
10 achieved by making an operating system (OS) share tasks with an application program or
by cooperation between the OS and the application program, storage of only the
application program portion in a recording medium is permissible.
[0031] Also, the computer program can be superimposed on a carrier wave to be
distributed via a communication network. For example, the computer program may be
15 posted on a bulletin board (BBS: Bulletin Board System) on a communication network,
and the computer program may be distributed via the communication network. In this
case, the above-described processing may be executed by starting the computer program
and executing the computer program in the same manner as another application program
under the control of the OS.
20 [0032] The circuit configuration of the power conversion system 1 is freely selected,
and is not limited to the above-described example. As an example, the contactors 4 and
5 may be connected in series, and the resistor 6 may be connected to the contactor 5 in
parallel. In this case, when the electric railway vehicle starts running, the contactor 5 is
closed after the contactor 4 is closed. That is, the contactors 4 and 5 are closed during
25 the running of the electric railway vehicle. When the stop command signal S2 reaches
the H level, both of the contactors 4 and 5 are opened.
[0033] The power collection method of the power conversion system 1 is not
1 6
limited to the above-described method using the overhead line, and a freely-selected
method for acquiring power from a substation can be used. Examples of the method for
collecting power include a ground-level power supply method, a method using a third rail
system, and the like. In a case of the ground-level power supply method or the method
5 using the third rail system, power can be acquired by touching current collecting shoes
against a third rail. Also, in the case of the method using the overhead line, the current
collector is a freely-selected device that acquires power from the overhead line 2, and
examples of the current collector include a trolley pole and a bow collector.
[0034] The operation command may include a coasting command in addition to the
10 power running command and the brake command. In this case, when the operation
command signal S1 indicates the coasting command, and the stop command signal S2 is
at the H level, the circuit controller 23 causes operation of the chopper circuit 14.
[0035] The configuration of the control device 20 is not limited to the
above-described example and may be a freely-selected configuration that suppresses the
15 overvoltage of the filter capacitor 11. As an example, the function of the contactor
controller 22 may be provided, as a contactor control device, separately from the control
device 20. In this case, the contactor control device opens the contactor 4 when the stop
command signal S2 reaches the H level.
[0036] The duty ratio is calculated according to a freely-selected function that is
20 positively correlated with the voltage EFC, a freely-selected table, or the like. As an
example, the duty ratio is calculated based on a linear function, a quadratic function, or
the like that uses the voltage of the filter capacitor 11 as a variable.
[0037] The step-down circuit provided on the pantograph 3-side of the power
converter 12 is not limited to the chopper circuit 14, and a freely-selected step-down
25 circuit can be provided. As an example, a switching regulator may be provided. The
condition for stopping the chopper circuit 14 is not limited to the example of step S18 in
FIG. 4. For example, a voltage detector for detecting a voltage on the pantograph 3-side
1 7
from the contactor 4 may be further provided, and the chopper circuit 14 may be stopped
based on the voltage on the pantograph 3-side of the contactor 4 that is detected by the
voltage detector. Specifically, the operation of the chopper circuit 14 may be stopped
when the voltage on the pantograph 3-side of the contactor 4 continues to be within a
5 desired range for a predetermined period or more.
[0038] The foregoing describes some example embodiments for explanatory
purposes. Although the foregoing discussion has presented specific embodiments,
persons skilled in the art will recognize that changes may be made in form and detail
without departing from the broader spirit and scope of the invention. Accordingly, the
10 specification and drawings are to be regarded in an illustrative rather than a restrictive
sense. This detailed description, therefore, is not to be taken in a limiting sense, and the
scope of the invention is defined only by the included claims, along with the full range of
equivalents to which such claims are entitled.
Reference Signs List
15 [0039]
1 Power conversion system for a railway vehicle
2 Overhead line
3 Pantograph
4, 5 Contactor
20 6, 16 Brake resistor
7 Reactor
8 Electric motor
9 Current detector
11 Filter capacitor
25 12 Power converter
13 Voltage detector
14 Chopper circuit
1 8
15 Switching element
20 Railway vehicle control device
21 Torque controller
22 Contactor controller
5 23 Circuit controller
24 Target calculator
31 Processor
32 Memory
33 Interface
10 S1 Operation command signal
S2 Stop command signal
1 9
We Claim :
1. A railway vehicle control device comprising:
a torque controller to control operation of switching elements included in a power
converter so as to adjust a torque of an electric motor, the power converter having a
5 primary side to which a power supply is connected and a secondary side to which the
electric motor is connected and being configured to perform bidirectional power
conversion between the primary side and the secondary side; and
a circuit controller to acquire a voltage on the primary side of the power converter
and, when the voltage on the primary side is equal to or higher than a reference voltage,
10 cause operation of a step-down circuit connected in parallel to the primary side,
wherein
upon acquiring a stop command that is an instruction to turn off the switching
elements of the power converter, the torque controller stops the operation of the switching
elements of the power converter, and
15 upon acquiring the stop command, the circuit controller causes operation of the
step-down circuit.
2. The railway vehicle control device according to claim 1, wherein
upon acquiring the stop command, the circuit controller sets a limit on a time
20 period during which the step-down circuit is operated.
3. The railway vehicle control device according to claim 1 or 2, wherein
the circuit controller acquires an operation command including a power running
command or a brake command,
25 when the operation command includes the brake command and the voltage on the
primary side is equal to or higher than a reference voltage, the circuit controller causes
operation of the step-down circuit, and
2 0
when the operation command includes the power running command, the circuit
controller causes operation of the step-down circuit upon acquiring the stop command.
4. The railway vehicle control device according to any one of claims 1 to 3,
5 wherein
the step-down circuit comprises a switching element and a resistor that are
connected to each other in series, and
the circuit controller adjusts a duty ratio of the switching element of the step-down
circuit based on a duty ratio that is positively correlated with the voltage on the primary
10 side and varies with time in response to a time variation in the voltage on the primary
side.
5. The railway vehicle control device according to claim 4, wherein
the circuit controller acquires an operation command including a power running
15 command or a brake command, and
a maximum value of the duty ratio in a case in which the operation command
includes the power running command is less than a maximum value of the duty ratio in a
case in which the operation command includes the brake command.
20
6. The railway
the circuit controller acquires an operation command
command or a brake command, and
the duty ratio in a case in which the operation command
running command, the circuit controller acquires the stop command, 5 and the volta
the primary side is equal to the reference voltage
which the operation command
primary side is equal to the reference voltage
Dated this 24th day of December, 2020
10
2 1
vehicle control device according to claim 4 or 5, wherein
including a power running
includes the power
is greater than the duty ratio
includes the brake command and the voltage on the
voltage.