Mobile

Abstract

To provide a power supply switching device and a drive control apparatus that enable a railway vehicle to travel even when the external power supply is stopped by a small-sized power storage device.SOLUTION: A power supply switching device 30 includes: a switching circuit 31 that is connected to a first power conversion device 10 and a low voltage power storage device 20 and forms a cable way between the first power conversion device 10 and the low voltage power storage device 20; and a switching control unit 32 that electrically separates the first power conversion device 10 and the low voltage power storage device 20 from each other by controlling the switching circuit 31 when the power is supplied from a main power supply 92 to the first power conversion device 10, and electrically connects the first power conversion device 10 with the low voltage power storage device 20 when the supply of the power from the main power supply 92 to the first power conversion device 10 stops in such a state that the railway vehicle is started.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power supply switching device and a drive control device. [Background technology]

[0002] A current collector mounted on an electric railway vehicle acquires electric power supplied from an external source via an overhead line, a current collector shoe, etc., and a drive control device drives an electric motor with the power supplied from the current collector, thereby causing the electric railway vehicle to run. Some electric railway vehicles are capable of running even when the supply of external power is stopped. An example of this type of electric railway vehicle is disclosed in Patent Document 1.

[0003] The railway vehicle disclosed in Patent Document 1 includes a running power conversion device that converts high-voltage AC power acquired by a current collecting device and stepped down by a transformer into running AC power and supplies it to a running motor, an auxiliary power supply power conversion device that converts the high-voltage AC power into load AC power and supplies it to an AC load, and converts the high-voltage AC power into load DC power and supplies it to a DC load, and a battery device. When power supply from the overhead line is stopped, a running DC-AC power conversion unit included in the running power conversion device converts DC power supplied from the battery device into running AC power and supplies it to the running motor, thereby enabling the railway vehicle to run. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-44978 Summary of the Invention [Problem to be solved by the invention]

[0005] In the railway vehicle disclosed in Patent Document 1, the battery device is connected between a running AC-DC power converter and a running DC-AC power converter of the running power converter. The intermediate link voltage between the running AC-DC power converter and the running DC-AC power converter of the running power converter is set to a high voltage of, for example, 700 V. For this reason, it is necessary to use a battery device with a high withstand voltage that can withstand the intermediate link voltage as the battery device. As the withstand voltage increases, the battery device becomes larger, and so the railway vehicle disclosed in Patent Document 1 has a problem in that it is necessary to mount a large battery device.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a power source switching device and a drive control device that enable a railway vehicle to run even when the external power supply is stopped using a small-sized power storage device. [Means for solving the problem]

[0007] In order to achieve the above object, a power supply switching device according to the present disclosure includes a switching circuit and a switching control unit. The switching circuit is connected to a first power conversion device that converts supplied power into power to be supplied to an electric motor that generates propulsive force for a railcar and supplies the converted power to the electric motor, and a low-voltage storage device that discharges power at a voltage lower than a voltage applied to the first power conversion device when power is supplied from a main power source to the first power conversion device, and forms an electric path between the first power conversion device and the low-voltage storage device. When power is supplied from the main power source to the first power conversion device, the switching control unit controls the switching circuit to electrically disconnect the first power conversion device and the low-voltage storage device from each other, and when the supply of power from the main power source to the first power conversion device is stopped while the railcar is started, the switching control unit controls the switching circuit to electrically connect the first power conversion device and the low-voltage storage device to each other. Effect of the Invention

[0008] The power supply switching device of the present disclosure electrically connects the first power conversion device and the low-voltage storage device to each other when the supply of power from the main power source to the first power conversion device is stopped. As a result, the first power conversion device converts the power supplied from the low-voltage storage device and supplies the converted power to the electric motor, thereby generating propulsion force for the railway vehicle. Therefore, a small-sized storage device that can be used as the low-voltage storage device enables the railway vehicle to run even when the power supply from the outside is stopped. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a block diagram showing a configuration of a drive control device according to a first embodiment. [Diagram 2] FIG. 1 is a diagram showing a circuit configuration of a drive control device according to a first embodiment; [Diagram 3] FIG. 1 is a block diagram showing a configuration of a conversion control device according to a first embodiment; [Figure 4] FIG. 1 is a block diagram showing a configuration of a first control unit according to a first embodiment; [Diagram 5] FIG. 1 is a block diagram showing a hardware configuration of a switching control unit and a conversion control device according to a first embodiment. [Figure 6] 1 is a timing chart showing an example of an operation of the drive control device according to the first embodiment when power is supplied from a main power source to a first power conversion device; [Figure 7] FIG. 1 is a diagram showing an example of a current flow in the drive control device according to the first embodiment when power is supplied from a main power source to a first power conversion device. [Figure 8] 10 is a timing chart showing an example of an operation of the drive control device according to the first embodiment when power supply from a main power source to a first power conversion device is stopped. [Figure 9] FIG. 1 is a diagram showing an example of a current flow in the drive control device according to the first embodiment when power supply from a main power source to a first power conversion device is stopped. [Figure 10] 10 is a timing chart showing an example of an operation of the drive control device according to the first embodiment when power supply from the main power source to the first power conversion device is resumed. [Figure 11]FIG. 13 is a diagram showing a circuit configuration of a drive control device according to a second embodiment. [Figure 12] FIG. 11 is a block diagram showing a configuration of a first control unit according to a second embodiment. [Figure 13] 11 is a flowchart showing an example of a process of a protection operation based on an applied voltage performed by a drive control device according to a second embodiment. [Figure 14] 11 is a flowchart showing an example of a process of a protection operation based on a terminal voltage of a capacitor, which is performed by a drive control device according to a second embodiment. [Figure 15] 11 is a flowchart showing an example of a process of a protection operation based on a voltage difference between an applied voltage and a terminal voltage of a capacitor, which is performed by a drive control device according to a second embodiment. [Figure 16] 11 is a flowchart showing an example of a process of a protection operation based on a current value performed by a drive control device according to a second embodiment. [Figure 17] FIG. 1 is a block diagram showing a modification of the hardware configuration of a switching control unit and a conversion control device according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] A power supply switching device and a drive control device according to an embodiment of the present disclosure will be described in detail below with reference to the drawings, in which the same or equivalent parts are denoted by the same reference numerals.

[0011] (Embodiment 1) A drive control device mounted on a railway vehicle using a DC power feeding system will be described in embodiment 1. The drive control device 1 shown in Fig. 1 includes a first power conversion device 10 that converts DC power supplied from a main power source 92 into power, for example, three-phase AC power, for supplying the power to a motor 91 that generates propulsive force for the railway vehicle, a low-voltage battery device 20 that is charged with the power supplied from the main power source 92, a power source switching device 30 that forms an electric path between the first power conversion device 10 and the low-voltage battery device 20, and a conversion control device 40 that controls the first power conversion device 10.

[0012] The power source switching device 30 and the conversion control device 40 receive, from the driver's cab (not shown), a start-up signal S1 that instructs the starting of the railway vehicle and an emergency running signal S2 that instructs the vehicle to run in an emergency by using the power stored in the low-voltage storage device 20 when the power supply from the main power source 92 is stopped.

[0013] The start signal S1 is a signal that goes to H (High) level when the railway vehicle starts and goes to L (Low) level when the railway vehicle stops. The emergency running signal S2 is a signal that goes to H level when the vehicle runs with the supply of power from the main power source 92 to the first power conversion device 10 stopped and goes to L level when the vehicle runs with the first power conversion device 10 receiving power from the main power source 92.

[0014] The electric motor 91 is, for example, a three-phase induction motor. In order to avoid complicating the drawing, only one electric motor 91 is illustrated in Fig. 1, but the first power conversion device 10 supplies power to one or a plurality of electric motors 91.

[0015] The main power source 92 is a current collector that collects power supplied from a substation via a power supply line. The current collector is, for example, a pantograph that collects power from an overhead line, a collector shoe that collects power from a third rail, or the like.

[0016] The power supply switching device 30 has a switching circuit 31 that forms an electrical path between the first power conversion device 10 and the low-voltage storage device 20, and a switching control unit 32 that controls the switching circuit 31 to electrically disconnect the first power conversion device 10 and the low-voltage storage device 20 from each other, or to electrically connect the first power conversion device 10 and the low-voltage storage device 20 to each other.

[0017] When the railway vehicle is not started or when power is supplied from the main power supply 92 to the first power conversion device 10, the switching control unit 32 controls the switching circuit 31 to electrically disconnect the first power conversion device 10 and the low-voltage storage device 20 from each other. In detail, when the start-up signal S1 is at L level, or when the start-up signal S1 is at H level and the emergency running signal S2 is at L level, the switching control unit 32 controls the switching circuit 31 to electrically disconnect the first power conversion device 10 and the low-voltage storage device 20 from each other.

[0018] When the supply of power from the main power source 92 to the first power conversion device 10 is stopped while the railway vehicle is started, the switching control unit 32 controls the switching circuit 31 to electrically connect the first power conversion device 10 and the low-voltage storage device 20 to each other. In detail, when the start-up signal S1 is at H level and the emergency running signal S2 is at H level, the switching control unit 32 controls the switching circuit 31 to electrically connect the first power conversion device 10 and the low-voltage storage device 20 to each other.

[0019] As a result, during emergency running, DC power is supplied from the low-voltage storage device 20 to the first power conversion device 10. The first power conversion device 10 converts the DC power supplied from the low-voltage storage device 20 into three-phase AC power and supplies the converted three-phase AC power to the electric motor 91, thereby driving the electric motor 91 and generating propulsion force for the railway vehicle. As described above, even when the supply of power from the main power source 92 to the first power conversion device 10 is stopped, the drive control device 1 can drive the electric motor 91 with power discharged from the low-voltage storage device 20 to run the railway vehicle.

[0020] Details of each part of the drive control device 1 will be described with reference to Fig. 2. In the example of Fig. 2, in addition to the configuration of Fig. 1, the drive control device 1 further includes a second power conversion device 50 that converts DC power supplied from a main power supply 92 into DC power and AC power and supplies the converted DC power and AC power to the low-voltage storage device 20 and a load device 93, respectively. The load device 93 is an electronic device mounted on a railway vehicle, such as lighting equipment, on-board equipment, etc.

[0021] The first power conversion device 10 has a positive input terminal 10a which is a positive terminal on the side of the main power supply 92, and a negative input terminal 10b which is a negative terminal on the side of the main power supply 92. The positive input terminal 10a is connected to the main power supply 92. The negative input terminal 10b is grounded.

[0022] The first power conversion device 10 includes a high-speed circuit breaker HB having one end connected to the main power supply 92 via the positive input terminal 10a, an inrush suppression circuit 11 that suppresses inrush current, a reactor L1 having one end connected to the output side of the inrush suppression circuit 11, a capacitor C1 that forms an LC filter together with the reactor L1 to reduce harmonic components, an inverter 12 that converts the DC power supplied via the capacitor C1 into three-phase AC power for supplying to the motor 91, and a discharge circuit 13 connected in parallel to the capacitor C1.

[0023] The high-speed circuit breaker HB is controlled by the conversion control device 40. When the high-speed circuit breaker HB is closed, the inrush suppression circuit 11 is electrically connected to the main power supply 92. When the high-speed circuit breaker HB is opened, the inrush suppression circuit 11 is electrically disconnected from the main power supply 92.

[0024] The inrush suppression circuit 11 has a main contactor LB, one end of which is connected to the high-speed circuit breaker HB and the other end of which is connected to the reactor L1, and a charging contactor CHB and a charging resistor CHR, which are connected in parallel to the main contactor LB and connected in series to each other. The main contactor LB and the charging contactor CHB are controlled by the conversion control device 40. When the main contactor LB or the charging contactor CHB is closed, the inverter 12 is electrically connected to the main power supply 92 via the inrush suppression circuit 11 and the high-speed circuit breaker HB, or the inverter 12 is electrically connected to the low-voltage storage device 20 via the inrush suppression circuit 11 and the switching circuit 31.

[0025] The inverter 12 is formed of, for example, a power conversion circuit with variable output voltage and output frequency. In detail, the inverter 12 has a plurality of switching elements controlled by a pulse width modulation signal output by the conversion control device 40, and free wheel diodes connected in parallel to each switching element. By switching operations of the plurality of switching elements, the inverter 12 converts DC power supplied via a capacitor C1 connected between primary terminals into three-phase AC power, and supplies the converted three-phase AC power to an electric motor 91 connected to secondary terminals.

[0026] Each switching element is an IGBT (Insulated Gate Bipolar Transistor), a GTO (Gate Turn-Off thyristor), a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor), etc. If each switching element is an IGBT, the anode of the freewheeling diode is connected to the emitter terminal of the switching element, and the cathode of the freewheeling diode is connected to the collector terminal of the switching element.

[0027] The reactor L1 and the capacitor C1 together form an LC filter that reduces harmonic components generated by the switching operations of the multiple switching elements that the inverter 12 has.

[0028] The capacitor C1 is connected between the primary terminals of the inverter 12 and is charged with DC power supplied from the main power supply 92 or the low-voltage power storage device 20.

[0029] The discharge circuit 13 has a discharge resistor OVR and a discharge switch OVT connected in series to each other. The discharge switch OVT is controlled by the conversion control device 40. The discharge switch OVT has, for example, an IGBT and a free wheel diode connected in parallel to the IGBT. When the discharge switch OVT is turned on, the capacitor C1 is electrically connected to the discharge resistor OVR, and the capacitor C1 is discharged.

[0030] The first power conversion device 10 is provided with a voltage sensor PT1 that measures the value of the voltage applied to the first power conversion device 10 as a voltage acquisition unit that acquires the value of the voltage applied to the first power conversion device 10. The first power conversion device 10 is further provided with a voltage sensor PT2 that measures the value of the voltage across the terminals of the capacitor C1 as a voltage acquisition unit that acquires the value of the voltage across the terminals of the capacitor C1. The measured values ​​of the voltage sensors PT1 and PT2 are sent to the conversion control device 40. The measured value of the voltage sensor PT2 is sent to the switching control unit 32 of the power source switching device 30.

[0031] The second power conversion device 50 includes a D / A (Digital / Analog) conversion circuit 51 having a circuit configuration similar to that of the first power conversion device 10, a transformer TR1 to which the D / A conversion circuit 51 is connected to a primary winding, which transforms the AC power output by the D / A conversion circuit 51 and outputs it from a secondary winding, an AC capacitor ACC1 connected to the secondary winding of the transformer TR1, and a rectifier circuit 52 that rectifies the AC power transformed by the transformer TR1 to DC power.

[0032] The D / A conversion circuit 51 has the same configuration as the first power conversion device 10, specifically, a high-speed circuit breaker HB, an inrush suppression circuit 11, a reactor L1, an inverter 12, a capacitor C1, a discharge circuit 13, and voltage sensors PT1 and PT2. The inverter 12 in the D / A conversion circuit 51 is a static inverter, and the output voltage and output frequency are maintained constant.

[0033] The transformer TR1 is, for example, a delta-star connected transformer, which transforms the AC power supplied from the D / A conversion circuit 51 connected to the primary winding into a voltage suitable for the load device 93, and outputs the transformed AC power from the secondary winding.

[0034] The AC capacitor ACC1 is connected to the secondary winding of the transformer TR1. The AC capacitor ACC1 forms an LC filter together with a coil of the transformer TR1 to reduce harmonic components generated by the switching operation of the inverter 12 of the D / A conversion circuit 51.

[0035] The rectifier circuit 52 rectifies the AC power transformed by the transformer TR1 into DC power, and supplies the rectified DC power to the low-voltage power storage device 20 and the conversion control device 40.

[0036] The low-voltage storage device 20 discharges at a voltage lower than the voltage applied to the first power conversion device 10 when power is supplied from the main power supply 92 to the first power conversion device 10. For example, the low-voltage storage device 20 discharges at a voltage in the range of 10% to 20% of the voltage applied to the first power conversion device 10 when power is supplied from the main power supply 92 to the first power conversion device 10. Specifically, when DC power of 750V is supplied from the main power supply 92 to the first power conversion device 10, the low-voltage storage device 20 discharges DC power of 100V.

[0037] The low-voltage energy storage device 20 includes a first battery module 21 having a plurality of battery cells connected in series with each other, and a second battery module 22 having a plurality of battery cells connected in series with each other. The first battery module 21 and the second battery module 22 are independent of each other.

[0038] A positive battery terminal 21a, which is a positive terminal of the first battery module 21, and a negative battery terminal 21b, which is a negative terminal of the first battery module 21, are electrically connected to the first power conversion device 10, or the second power conversion device 50 and the conversion control device 40 via a switching circuit 31. The first battery module 21 is charged with DC power output by the second power conversion device 50.

[0039] The first battery module 21 is electrically connected to or electrically disconnected from the first power conversion device 10 by the switching control unit 32 controlling the switching circuit 31. When the first battery module 21 is electrically connected to the first power conversion device 10, the low-voltage electricity storage device 20 supplies the power stored in the first battery module 21 to the first power conversion device 10.

[0040] The second battery module 22 is electrically connected to the second power conversion device 50 and the conversion control device 40. In detail, the positive terminal of the second battery module 22 is connected to a connection point between the positive output terminal of the second power conversion device 50 and the positive power supply terminal of the conversion control device 40. The negative terminal of the second battery module 22 is connected to a connection point between the negative output terminal of the second power conversion device 50 and the negative power supply terminal of the conversion control device 40. When the supply of power from the second power conversion device 50 to the conversion control device 40 is stopped, the low-voltage storage device 20 supplies the power stored in the second battery module 22 to the conversion control device 40. Specifically, the second battery module 22 serves as a control power source for the conversion control device 40 when the railcar is started and when it is running in an emergency after it is started. The second battery module 22 is charged with DC power output by the second power conversion device 50.

[0041] The switching circuit 31 is electrically connected to the first power conversion device 10, the first battery module 21 of the low-voltage storage device 20, and the second power conversion device 50. The switching circuit 31 forms an electric path between the first power conversion device 10 and the first battery module 21 of the low-voltage storage device 20, and an electric path between the second power conversion device 50 and the first battery module 21 of the low-voltage storage device 20.

[0042] In detail, the switching circuit 31 has a first contactor LS1 and a second contactor LS2 as at least one power supply contactor electrically connected to the first power conversion device 10 and the low-voltage storage device 20. The switching circuit 31 further has a third contactor LS3 and a fourth contactor LS4 as at least one charging contactor electrically connected to the low-voltage storage device 20 and the second power conversion device 50.

[0043] The switching circuit 31 preferably further includes a fuse BTF provided in an electric path between the first power conversion device 10 and the low-voltage storage device 20. When a current exceeding a rated current flows, the fuse BTF melts and electrically separates the first power conversion device 10 and the low-voltage storage device 20 from each other. By providing the fuse BTF, an overcurrent is prevented from flowing to the low-voltage storage device 20.

[0044] The switching circuit 31 will be described in detail below. One end of the first contactor LS1 is connected to the positive input terminal 10a of the first power converter 10 via a high-speed circuit breaker HB. In detail, one end of the first contactor LS1 is connected to a connection point between the other end of the high-speed circuit breaker HB and one end of the main contactor LB and one end of the charging contactor CHB of the inrush suppression circuit 11. The other end of the first contactor LS1 is connected to the positive battery terminal 21a of the first battery module 21 via a fuse BTF.

[0045] One end of the second contactor LS2 is connected to the negative input terminal 10b of the first power conversion device 10. The other end of the second contactor LS2 is connected to the negative battery terminal 21b of the first battery module .

[0046] One end of the third contactor LS3 is connected to a connection point between a positive output terminal which is a positive output terminal of the second power conversion device 50 and a positive power supply terminal which is a positive terminal of the conversion control device 40. The other end of the third contactor LS3 is connected to the positive battery terminal 21a of the first battery module 21.

[0047] One end of the fourth contactor LS4 is connected to a connection point between the negative output terminal which is the negative output terminal of the second power conversion device 50 and the negative power supply terminal which is the negative terminal of the conversion control device 40. The other end of the fourth contactor LS4 is connected to the negative battery terminal 21b of the first battery module 21.

[0048] When the first contactor LS1 and the second contactor LS2 are closed and the third contactor LS3 and the fourth contactor LS4 are open, the first power conversion device 10 and the first battery module 21 of the low-voltage storage device 20 are electrically connected, and the first battery module 21 supplies DC power to the first power conversion device 10.

[0049] When the first contactor LS1 and the second contactor LS2 are opened and the third contactor LS3 and the fourth contactor LS4 are closed, the first power conversion device 10 and the first battery module 21 of the low-voltage energy storage device 20 are electrically disconnected, and the second power conversion device 50 and the conversion control device 40 are electrically connected to the first battery module 21 of the low-voltage energy storage device 20. As a result, it becomes possible to charge the low-voltage energy storage device 20 with the DC power output by the second power conversion device 50.

[0050] The switching control unit 32 controls the first contactor LS1, the second contactor LS2, the third contactor LS3, and the fourth contactor LS4 based on the start signal S1, the emergency run signal S2, and the measurement value of the voltage sensor PT2.

[0051] In detail, when the start signal S1 is at L level, or when the start signal S1 is at H level and the emergency running signal S2 is at L level, the switching control unit 32 opens the first contactor LS1 and the second contactor LS2 to electrically separate the first power conversion device 10 and the first battery module 21 of the low-voltage storage device 20 from each other. At this time, the switching control unit 32 closes the third contactor LS3 and the fourth contactor LS4 to electrically connect the second power conversion device 50 and the conversion control device 40 to the first battery module 21 of the low-voltage storage device 20 from each other.

[0052] When the start signal S1 is at H level and the emergency running signal S2 is at H level, the switching control unit 32 closes the first contactor LS1 and the second contactor LS2 to electrically connect the first power conversion device 10 and the first battery module 21 of the low-voltage storage device 20 to each other. At this time, the switching control unit 32 opens the third contactor LS3 and the fourth contactor LS4 to electrically disconnect the second power conversion device 50 and the conversion control device 40 from the first battery module 21 of the low-voltage storage device 20 to each other.

[0053] The conversion control device 40 controls the first power conversion device 10 and the second power conversion device 50 based on the start signal S1, the emergency run signal S2, and an operation command signal (not shown). The operation command signal is a signal output from a main controller provided in the driver's cab and indicates a target acceleration of the railway vehicle according to the operation of the main controller. In detail, as shown in Fig. 3, the conversion control device 40 has a first control unit 41 that controls the first power conversion device 10 and a second control unit 42 that controls the second power conversion device 50.

[0054] The first control unit 41 closes or opens the high-speed circuit breaker HB, main contactor LB, and charging contactor CHB of the first power conversion device 10, and switches on and off the discharge switch OVT of the first power conversion device 10 and multiple switching elements of the inverter 12. Similarly, the second control unit 42 closes or opens the high-speed circuit breaker HB, main contactor LB, and charging contactor CHB of the D / A conversion circuit 51 of the second power conversion device 50, and switches on and off the discharge switch OVT of the D / A conversion circuit 51 of the second power conversion device 50 and multiple switching elements of the inverter 12.

[0055] Since the first control unit 41 and the second control unit 42 have the same configuration, the details of the first control unit 41 will be described with reference to Fig. 4. As shown in Fig. 4, the first control unit 41 has a circuit breaker control unit 43 that closes or opens the high-speed circuit breaker HB, a contactor control unit 44 that closes or opens the main contactor LB and the charging contactor CHB, a discharge control unit 45 that switches the discharge switch OVT on and off, and a switching control unit 46 that switches the multiple switching elements of the inverter 12 on and off.

[0056] The circuit breaker control unit 43 closes or opens the high speed circuit breaker HB based on the start signal S1 and the emergency run signal S2.

[0057] The contactor control unit 44 acquires measured values ​​from the voltage sensors PT1 and PT2. The contactor control unit 44 closes or opens the main contactor LB and the charging contactor CHB based on the start signal S1, the emergency run signal S2, and the measured values ​​of the voltage sensors PT1 and PT2.

[0058] The discharge control unit 45 obtains a measurement value from the voltage sensor PT2 and obtains a pulse width modulation signal from the switching control unit 46. The discharge control unit 45 switches the discharge switch OVT on and off based on the start signal S1, the emergency running signal S2, the measurement value of the voltage sensor PT2, and the pulse width modulation signal.

[0059] The switching control unit 46 acquires the measurement value of the voltage sensor PT2 and an operation command signal sent from the cab. The switching control unit 46 generates a pulse width modulation signal for controlling each switching element of the inverter 12 in response to the start signal S1, the emergency running signal S2, the measurement value of the voltage sensor PT2, and the operation command signal. The switching control unit 46 switches the switching elements on and off by sending each pulse width modulation signal to the switching elements.

[0060] FIG. 5 shows the hardware configuration of the control part of the drive control device 1 having the above configuration, in other words, the switching control unit 32 and the conversion control device 40. The switching control unit 32 and the conversion control device 40 each include a processor 81, a memory 82, and an interface 83. The processor 81, the memory 82, and the interface 83 are connected to each other via a bus 80. The functions of each part of the switching control unit 32 and the conversion control device 40 are realized by software, firmware, or a combination of software and firmware. The software and firmware are written as programs and stored in the memory 82. The processor 81 reads and executes the programs stored in the memory 82 to realize the functions of each part described above. That is, the memory 82 stores a program for executing the processing of the switching control unit 32 or the processing of each part of the conversion control device 40.

[0061] Memory 82 includes, for example, non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read-Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read-Only Memory), magnetic disks, flexible disks, optical disks, compact disks, mini disks, DVDs (Digital Versatile Discs), etc.

[0062] The switching control unit 32 is connected to the first contactor LS1, the second contactor LS2, the third contactor LS3, the fourth contactor LS4, and the voltage sensor PT2 via an interface 83. The conversion control device 40 is connected to the high-speed circuit breaker HB, the main contactor LB, the charging contactor CHB, the discharge switch OVT, the inverter 12, and the voltage sensors PT1 and PT2 via the interface 83. The interface 83 has an interface module compliant with one or more standards depending on the connection destination.

[0063] The driving of the electric motor 91 performed by the drive control device 1 having the above configuration will be described with reference to Fig. 6 and Fig. 7. Fig. 6 shows an example of the operation of the drive control device 1 when power is supplied from the main power supply 92 to the first power conversion device 10 and the second power conversion device 50. As shown in graph A of Fig. 6, the timing when the start signal S1 changes from L level to H level is defined as time T1. In the example of Fig. 6, as shown in graph B, the emergency running signal S2 is maintained at L level, and emergency running is not performed. While emergency running is not performed, as shown in graph G, the discharge switch OVT is maintained in the off state.

[0064] Before time T1, the railcar is not started, and the high-speed circuit breaker HB, main contactor LB, charging contactor CHB, first contactor LS1, second contactor LS2, third contactor LS3, and fourth contactor LS4 are open. Therefore, before time T1, the first power conversion device 10, the second power conversion device 50, the motor 91, and the load device 93 are not supplied with power and are stopped.

[0065] At time T1, when the start-up signal S1 changes from L level to H level, the switching control unit 32 maintains the first contactor LS1 and the second contactor LS2 in an open state and closes the third contactor LS3 and the fourth contactor LS4, as shown in graphs I, J, K, and L of Fig. 6. As a result, the first battery module 21 of the low-voltage electricity storage device 20 is electrically connected to the second power conversion device 50 and the conversion control device 40, and is electrically disconnected from the first power conversion device 10.

[0066] Thereafter, as shown in graph C of FIG. 6, the time when the circuit breaker control unit 43 of the first control unit 41 of the conversion control device 40 closes the high-speed circuit breaker HB is set to time T2. When the high-speed circuit breaker HB is closed, DC power is supplied from the main power source 92 to the first power conversion device 10. As a result, as shown in graph D of FIG. 6, at time T2, the applied voltage to the first power conversion device 10 indicated by the measurement value of the voltage sensor PT1 starts to rise from a voltage value Va1. The voltage value Va1 is a value that can be considered to be 0V. The time when the applied voltage to the first power conversion device 10 reaches a normal minimum applied voltage ESL0, which is the lower limit of the applied voltage required to drive the motor 91 when power is supplied from the main power source 92 to the first power conversion device 10, is set to time T3. After time T3, the applied voltage to the first power conversion device 10 is assumed to rise to a voltage value Va2. The voltage value Va2 is a value that can be considered to match the overhead line voltage.

[0067] As shown in graph E of Fig. 6, when the measurement value of the voltage sensor PT1, which indicates the value of the voltage applied to the first power conversion device 10, reaches the normal minimum applied voltage ESL0 at time T3, the contactor control unit 44 of the first control unit 41 included in the conversion control device 40 closes the charging contactor CHB. When the charging contactor CHB is closed, a current flows from the main power supply 92 through the high-speed circuit breaker HB, the charging contactor CHB, and the charging resistor CHR to the capacitor C1. This suppresses an inrush current from flowing to the capacitor C1.

[0068] When the charging contactor CHB is closed and a current flows as described above, charging of the capacitor C1 starts, and as shown in graph F of FIG. 6, at time T3, the terminal voltage of the capacitor C1 indicated by the measurement value of the voltage sensor PT2 starts to rise from the voltage value Vb1. The voltage value Vb1 is a value at which the capacitor C1 is considered to be discharged, for example, a value at which the capacitor C1 is considered to be 0V. The time at which the difference between the terminal voltage of the capacitor C1 and the voltage applied to the first power conversion device 10 becomes equal to or less than the upper limit of the voltage difference at which the capacitor C1 is considered to be sufficiently charged is defined as time T4. The terminal voltage of the capacitor C1 at this time is defined as EFCL0. After time T4, the terminal voltage of the capacitor C1 is assumed to rise to the voltage value Vb2.

[0069] 6, when the difference between the terminal voltage of capacitor C1 and the voltage applied to first power conversion device 10 becomes equal to or less than an upper limit, contactor control unit 44 of first control unit 41 closes main contactor LB and opens charging contactor CHB. As a result, a current flows from main power supply 92 through high-speed circuit breaker HB and main contactor LB to capacitor C1.

[0070] After time T4 when the inter-terminal voltage of capacitor C1 indicated by the measurement value of voltage sensor PT2 reaches voltage EFCL0, the switching control unit 46 of the first control unit 41 of the conversion control device 40 generates a pulse width modulation signal for each switching element of the inverter 12 in response to the operation command signal.

[0071] In detail, the switching control unit 46 determines a torque command value τ*, which is a target value of the torque of the electric motor 91, based on the target acceleration indicated by the operation command signal and a measured value of the rotation speed of the electric motor 91 acquired from a speed sensor (not shown). The switching control unit 46 determines an excitation current command value id* and a torque current command value iq* according to the torque command value τ*.

[0072] The switching control unit 46 performs conversion from three-phase coordinates to dq rotation coordinates based on an estimated rotor position θ of the motor 91 obtained by integrating the measured value of the rotation speed of the motor 91 and each phase current of the motor 91 acquired from a current sensor (not shown), to obtain an excitation current value id and a torque current value iq. The switching control unit 46 determines an excitation voltage command value Vd* from the difference between the excitation current value id and the excitation current command value id*, and determines a torque voltage command value Vq* from the difference between the torque current value iq and the torque current command value iq*.

[0073] The switching control unit 46 converts the excitation voltage command value Vd* and the torque voltage command value Vq* from the dq rotational coordinates to three-phase coordinates based on the estimated position θ to determine a U-phase voltage command value Vu, a V-phase voltage command value Vv, and a W-phase voltage command value Vw, and generates sine waves of each phase indicating the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw. The switching control unit 46 generates a pulse width modulation signal by comparing a triangular wave, which is a carrier wave, with the sine waves of each phase.

[0074] The switching control unit 46 sends the above-mentioned pulse width modulation signal to each switching element of the inverter 12 to control the on / off of each switching element, whereby the DC power supplied to the inverter 12 from the main power supply 92 is converted into three-phase AC power, and the three-phase AC power is supplied to the electric motor 91. As a result, the electric motor 91 is driven to generate propulsive force for the railway vehicle.

[0075] Although not shown in FIG. 6, the second control unit 42 of the conversion control device 40 performs the same control as the first control unit 41. Specifically, the second control unit 42 turns on the high-speed circuit breaker HB of the D / A conversion circuit 51 at time T2, turns on the charging contactor CHB at time T3, and turns on the main contactor LB and opens the charging contactor CHB at time T4. After time T4, the switching control unit 46 of the second control unit 42 controls the on / off of multiple switching elements of the inverter 12 of the D / A conversion circuit 51, thereby converting the DC power supplied from the main power source 92 to the D / A conversion circuit 51 into AC power and supplying it to the load device 93 and the rectifier circuit 52. The rectifier circuit 52 rectifies the AC power into DC power, and supplies the DC power to the low-voltage storage device 20 and the conversion control device 40.

[0076] After time T4, power is supplied from the main power supply 92 to the first power conversion device 10 and the second power conversion device 50, as shown by the arrows in Fig. 7. The first power conversion device 10 converts the DC power supplied from the main power supply 92 into three-phase AC power and supplies the converted three-phase AC power to the main motor 91, thereby driving the main motor 91 and generating propulsive force for the railway vehicle.

[0077] 7, the second power conversion device 50 converts the DC power supplied from the main power supply 92 into AC power and supplies the converted AC power to the load device 93, thereby operating the load device 93. The second power conversion device 50 converts the DC power supplied from the main power supply 92 into low-voltage DC power and supplies the low-voltage DC power to the low-voltage power storage device 20 and the conversion control device 40, thereby charging the first battery module 21 and the second battery module 22 of the low-voltage power storage device 20, and the conversion control device 40 operates using the low-voltage DC power supplied from the second power conversion device 50.

[0078] The operation of the drive control device 1 when the railway vehicle travels through a section without electrification facilities, such as a non-electrified section or a section between a storage yard and an electrified section, after time T4 in Fig. 6 will be described with reference to Fig. 8 and Fig. 9. As shown in graph B in Fig. 8, the time when the emergency running signal S2 becomes H level in response to the operation of a monitor device provided in the driver's cab, for example, is set to time T11.

[0079] When the emergency run signal S2 goes to H level at time T11, the circuit breaker control unit 43 of the first control unit 41 in the conversion control device 40 opens the high-speed circuit breaker HB. As a result, as shown in graph D of Fig. 8, at time T11, the voltage applied to the first power conversion device 10 starts to decrease from the voltage value Va2.

[0080] When the emergency run signal S2 goes to H level at time T11, as shown in graph H of FIG. 8, the contactor control unit 44 of the first control unit 41 of the conversion control device 40 opens the main contactor LB that has been closed.

[0081] When the emergency run signal S2 goes to H level at time T11, the switching control unit 46 of the first control unit 41 included in the conversion control device 40 turns off the multiple switching elements of the inverter 12 to stop the inverter 12. As a result, the power conversion by the first power conversion device 10 is stopped.

[0082] Although not shown in Fig. 8, when the emergency run signal S2 becomes H level at time T11, the second control unit 42 of the conversion control device 40 performs the same operation as the first control unit 41 described above. Specifically, at time T11, the circuit breaker control unit 43 of the second control unit 42 of the conversion control device 40 opens the high-speed circuit breaker HB of the D / A conversion circuit 51, the contactor control unit 44 of the second control unit 42 opens the main contactor LB of the D / A conversion circuit 51 that is closed, and the switching control unit 46 of the second control unit 42 turns off multiple switching elements of the inverter 12 of the D / A conversion circuit 51 to stop the inverter 12. As a result, the power conversion by the second power conversion device 50 is stopped.

[0083] When the emergency running signal S2 becomes H level at time T11, as shown in graph F, the terminal voltage of the capacitor C1 is a voltage value Vb2, which is higher than the maximum terminal voltage V0 in emergency, which is set lower than the discharge voltage of the low-voltage storage device 20. If the terminal voltage of the capacitor C1 is higher than the maximum terminal voltage V0 in emergency when the emergency running signal S2 becomes H level, the discharge control unit 45 of the first control unit 41 of the conversion control device 40 turns on the discharge switch OVT after each switching element of the inverter 12 is turned off by the switching control unit 46 of the first control unit 41, as shown in graph G. As a result, as shown in graph F, at time T11, the terminal voltage of the capacitor C1 starts to decrease from the voltage value Vb2. Thereafter, as shown in graph F, the timing at which the terminal voltage of the capacitor C1 reaches the maximum terminal voltage V0 in emergency is set to be time T12.

[0084] At time T12, when the terminal voltage of the capacitor C1 becomes equal to or lower than the emergency maximum terminal voltage V0, in other words, when the capacitor C1 is discharged, the switching control unit 32 of the power source switching device 30 opens the third contactor LS3 and the fourth contactor LS4 and then closes the first contactor LS1 and the second contactor LS2, as shown in graphs I, J, K, and L. As a result, the first battery module 21 of the low-voltage storage device 20 is electrically connected to the first power conversion device 10.

[0085] After time T12, as shown by the arrows in Fig. 9, DC power is supplied from the first battery module 21 to the first power conversion device 10, and DC power is supplied from the second battery module 22 to the conversion control device 40. As shown in graph D of Fig. 8, at time T12, when the first battery module 21 is electrically connected to the first power conversion device 10, the voltage applied to the first power conversion device 10 starts to rise from a voltage value Va1.

[0086] Time T13 is the time when the voltage applied to the first power conversion device 10 reaches an emergency minimum applied voltage ESL1, which is the lower limit of the applied voltage required to drive the motor 91 during emergency running. The emergency minimum applied voltage ESL1 is set lower than a normal minimum applied voltage ESL0, which is the lower limit of the applied voltage required to drive the motor 91 when power is supplied from the main power source 92 to the first power conversion device 10. This enables the first power conversion device 10 to operate by receiving DC power output from the low-voltage storage device 20, which has a lower voltage than the main power source 92. After time T13, the voltage applied to the first power conversion device 10 rises to a voltage value Va3. The voltage value Va3 is a value lower than the voltage value Va2, which corresponds to the overhead line voltage.

[0087] As shown in graph E, when the measurement value of the voltage sensor PT1, which indicates the value of the voltage applied to the first power conversion device 10, reaches the emergency minimum applied voltage ESL1 at time T13, the contactor control unit 44 of the first control unit 41 included in the conversion control device 40 closes the charging contactor CHB. When the charging contactor CHB is closed, a current flows from the low-voltage storage device 20 through the charging contactor CHB and the charging resistor CHR to the capacitor C1. This suppresses an inrush current from flowing to the capacitor C1.

[0088] When the charging contactor CHB is turned on and a current flows as described above, charging of the capacitor C1 starts, and as shown in graph F, at time T13, the terminal voltage of the capacitor C1 starts to rise from a voltage value V0. Time T14 is the time when the difference between the terminal voltage of the capacitor C1 and the voltage applied to the first power conversion device 10 becomes equal to or less than the upper limit of the voltage difference at which the capacitor C1 is considered to be fully charged. The terminal voltage of the capacitor C1 at this time is EFCL1. The upper limit of the voltage difference at which the capacitor C1 is considered to be fully charged is set to be smaller than the upper limit of the voltage difference at which the capacitor C1 is considered to be fully charged when power is supplied from the main power source 92 to the first power conversion device 10. After time T14, the terminal voltage of the capacitor C1 is assumed to rise to a voltage value Vb3.

[0089] 8, when the difference between the terminal voltage of the capacitor C1 and the voltage applied to the first power conversion device 10 becomes equal to or less than an upper limit value, the contactor control unit 44 of the first control unit 41 closes the main contactor LB and opens the charging contactor CHB. As a result, a current flows from the low-voltage storage device 20 through the main contactor LB to the capacitor C1.

[0090] When the terminal voltage of the capacitor C1 rises to a voltage value Vb3, the switching control unit 46 of the first control unit 41 of the conversion control device 40 sends a pulse width modulation signal to each switching element of the inverter 12 in response to the operation command signal to switch on and off each switching element. The control of each switching element of the inverter 12 by the switching control unit 46 is similar to the example of FIG. 6. However, the amplitude of the sine wave of each phase indicating the U-phase voltage command value Vu, the V-phase voltage command value Vv, and the W-phase voltage command value Vw when power is supplied from the low-voltage storage device 20 to the first power conversion device 10 is larger than when power is supplied from the main power source 92 to the first power conversion device 10. In other words, the modulation rate of the pulse width modulation signal when power is supplied from the low-voltage storage device 20 to the first power conversion device 10 is higher than when power is supplied from the main power source 92 to the first power conversion device 10. As a result, the pulse width of the pulse width modulation signal becomes wider than when power is supplied to the first power conversion device 10 from the main power supply 92. This makes it possible to rotate the electric motor 91 at a speed sufficient to generate propulsive force for the railway vehicle even if the voltage of the DC power supplied to the inverter 12 is low.

[0091] The operation of the drive control device 1 when the railway vehicle reaches the electrified section after time T14 in Fig. 8 will be described with reference to Fig. 10. As shown in graph B in Fig. 10, the time when the railway vehicle reaches the electrified section and the emergency running signal S2 goes to L level by the monitor device provided in the driver's cab is set to time T21.

[0092] When the emergency run signal S2 goes to L level at time T21, the switching control unit 32 of the power source switching device 30 opens the first contactor LS1 and the second contactor LS2, and then closes the third contactor LS3 and the fourth contactor LS4, as shown in graphs I, J, K, and L. As a result, the first battery module 21 of the low-voltage power storage device 20 is electrically connected to the second power conversion device 50 and the conversion control device 40.

[0093] When the third contactor LS3 and the fourth contactor LS4 are closed, the circuit breaker control unit 43 of the first control unit 41 of the conversion control device 40 closes the high-speed circuit breaker HB. The circuit breaker control unit 43 closes the high-speed circuit breaker HB after, for example, the time required for opening the first contactor LS1 and the second contactor LS2 and closing the third contactor LS3 and the fourth contactor LS4 has elapsed since the emergency running signal S2 became L level. As a result, as shown in graph D of FIG. 10, the voltage applied to the first power conversion device 10 starts to rise from the voltage value Va3. The time when the voltage applied to the first power conversion device 10 reaches the normal minimum applied voltage ESL0, which is the lower limit of the applied voltage required to drive the motor 91, is set to time T22. After time T22, the voltage applied to the first power conversion device 10 is assumed to rise to the voltage value Va2.

[0094] As shown in graph E of Fig. 10, when the measurement value of the voltage sensor PT1, which indicates the value of the voltage applied to the first power conversion device 10, reaches the normal minimum applied voltage ESL0 at time T22, the contactor control unit 44 of the first control unit 41 included in the conversion control device 40 closes the charging contactor CHB. When the charging contactor CHB is closed, a current flows from the main power supply 92 through the high-speed circuit breaker HB, the charging contactor CHB, and the charging resistor CHR to the capacitor C1. This suppresses an inrush current from flowing to the capacitor C1.

[0095] When the charging contactor CHB is closed and a current flows as described above, charging of the capacitor C1 begins, and as shown in graph F of Fig. 10, at time T22, the terminal voltage of the capacitor C1 starts to rise from a voltage value Vb3. Time T23 is the time when the difference between the terminal voltage of the capacitor C1 and the voltage applied to the first power conversion device 10 becomes equal to or less than the upper limit of the voltage difference at which the capacitor C1 is considered to be sufficiently charged. The terminal voltage of the capacitor C1 at this time is EFCL0. After time T23, the terminal voltage of the capacitor C1 is assumed to rise to a voltage value Vb2.

[0096] 10, when the difference between the terminal voltage of capacitor C1 and the voltage applied to first power conversion device 10 becomes equal to or less than an upper limit, contactor control unit 44 of first control unit 41 closes main contactor LB and opens charging contactor CHB. As a result, a current flows from main power supply 92 through high-speed circuit breaker HB and main contactor LB to capacitor C1.

[0097] When the voltage across the capacitor C1 rises to a voltage value Vb2, the switching control unit 46 of the first control unit 41 included in the conversion control device 40 generates a pulse width modulation signal for each switching element of the inverter 12 in response to an operation command.

[0098] The switching control unit 46 sends the above-mentioned pulse width modulation signal to each switching element of the inverter 12 to control the on / off of each switching element, whereby the DC power supplied to the inverter 12 from the main power supply 92 is converted into three-phase AC power, and the three-phase AC power is supplied to the electric motor 91. As a result, the electric motor 91 is driven to generate propulsive force for the railway vehicle.

[0099] 10, the second control unit 42 included in the conversion control device 40 performs the same control as the first control unit 41. Specifically, when the third contactor LS3 and the fourth contactor LS4 are closed, the second control unit 42 closes the high-speed circuit breaker HB, closes the charging contactor CHB at time T22, and closes the main contactor LB and opens the charging contactor CHB at time T23.

[0100] After time T23, power is supplied from the main power supply 92 to the first power conversion device 10 and the second power conversion device 50, as in Fig. 7. The first power conversion device 10 converts the DC power supplied from the main power supply 92 into three-phase AC power and supplies the converted three-phase AC power to the main motor 91, thereby driving the main motor 91 and generating propulsive force for the railway vehicle.

[0101] As described above, according to the power supply switching device 30 provided in the drive control device 1 according to the first embodiment, during emergency running, the first power conversion device 10 and the low-voltage storage device 20 are electrically connected, and DC power is supplied from the low-voltage storage device 20 to the first power conversion device 10. As a result, even if the power supply from the main power source 92 to the first power conversion device 10 is stopped, the DC power supplied from the low-voltage storage device 20 is converted into three-phase AC power, and the three-phase AC power is supplied to the electric motor 91, thereby generating a propulsive force for the railway vehicle. Since the low-voltage storage device 20 is a low-voltage storage device that serves as a control power source for the conversion control device 40 that controls the first power conversion device 10, it is possible to use a small-sized storage device as the low-voltage storage device 20. Therefore, according to the power supply switching device 30 and the drive control device 1 according to the first embodiment, the small-sized low-voltage storage device 20 enables the railway vehicle to run even when the power supply from the main power source 92 is stopped.

[0102] (Embodiment 2) The drive control device 1 may have a function of protecting the inverter 12 when an abnormality occurs in the inverter 12, such as a ground fault, overvoltage, overcurrent, etc. A drive control device 1 having a function of protecting the inverter 12 will be described in a second embodiment. A first power conversion device 10 included in the drive control device 1 shown in FIG. 11 is provided with a current sensor CT1 that measures the value of a current flowing through the first power conversion device 10 as a current acquisition unit that acquires the value of a current flowing through the first power conversion device 10. For example, the current sensor CT1 is provided in an electric path between a negative terminal of the primary terminals of the inverter 12 and the second contactor LS2.

[0103] A first control unit 41 included in the conversion control device 40 performs a protective operation for the inverter 12 included in the first power conversion device 10, and a second control unit 42 included in the conversion control device 40 performs a protective operation for protecting the inverter 12 of the D / A conversion circuit 51 included in the second power conversion device 50. Since the first control unit 41 and the second control unit 42 have the same configuration, the configuration of the first control unit 41 will be described.

[0104] As shown in Fig. 12, the first control unit 41 includes a protection determination unit 47 that determines whether protection of the inverter 12 is required, in addition to the configuration of the first control unit 41 according to the first embodiment. The protection determination unit 47 acquires the measurement value of the voltage sensor PT1, the measurement value of the voltage sensor PT2, the measurement value of the current sensor CT1, and the emergency running signal S2. The protection determination unit 47 determines whether protection of the inverter 12 is required, based on at least one of the measurement value of the voltage sensor PT1, the measurement value of the voltage sensor PT2, and the measurement value of the current sensor CT1. When the protection determination unit 47 determines that protection is required, it sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32.

[0105] An example of a protection operation of the inverter 12 of the first power conversion device 10 performed by the conversion control device 40 will be described with reference to Fig. 13. When the inverter 12 starts operating under the control of the switching control unit 46, the protection determination unit 47 starts processing of the protection operation shown in Fig. 13.

[0106] The protection determination unit 47 acquires a measurement value of the voltage sensor PT1 indicating the value of the voltage applied to the first power conversion device 10 (step S11). When the emergency running signal is at L level, that is, when emergency running is not in progress (step S12; No), the protection determination unit 47 determines whether or not the voltage applied to the first power conversion device 10 acquired in step S11 is less than a normal minimum applied voltage ESL0 which is a lower limit of the applied voltage required to drive the motor 91 when power is supplied from the main power supply 92 to the first power conversion device 10 (step S13).

[0107] If the applied voltage to the first power conversion device 10 acquired in step S11 is lower than the normal minimum applied voltage ESL0 (step S13; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S14).

[0108] If the voltage applied to the first power converter 10 acquired in step S11 is equal to or higher than the normal minimum applied voltage ESL0 (step S13; No), the process of step S14 is not performed.

[0109] When the emergency running signal is at H level, that is, when the vehicle is running in an emergency (step S12; Yes), the protection determination unit 47 determines whether or not the applied voltage to the first power conversion device 10 acquired in step S11 is less than an emergency minimum applied voltage ESL1, which is a lower limit of the applied voltage required to drive the motor 91 during emergency running (step S15). As in the first embodiment, the emergency minimum applied voltage ESL1 is set lower than the normal minimum applied voltage ESL0.

[0110] If the applied voltage to the first power conversion device 10 acquired in step S11 is less than the minimum emergency applied voltage ESL1 (step S15; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S16).

[0111] If the voltage applied to the first power converter 10 acquired in step S11 is equal to or higher than the minimum emergency voltage ESL1 (step S15; No), the process of step S16 is not performed.

[0112] The protection determination unit 47 repeats the above-mentioned process while the inverter 12 is operating under the control of the switching control unit 46.

[0113] Another example of the protection operation of the inverter 12 of the first power conversion device 10 performed by the conversion control device 40 will be described with reference to Fig. 14. When the inverter 12 starts operating under the control of the switching control unit 46, the protection determination unit 47 starts processing of the protection operation shown in Fig. 14.

[0114] The protection determination unit 47 acquires a measurement value of the voltage sensor PT2 that measures the value of the terminal voltage of the capacitor C1 (step S21). When the emergency running signal is at L level, that is, when emergency running is not in progress (step S22; No), the protection determination unit 47 determines whether or not the terminal voltage of the capacitor C1 acquired in step S21 is less than a normal minimum terminal voltage that is a lower limit value of the terminal voltage of the capacitor C1 required to drive the motor 91 when power is supplied from the main power source 92 to the first power conversion device 10 (step S23).

[0115] If the terminal voltage of capacitor C1 acquired in step S21 is less than the normal minimum terminal voltage (step S23; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S24).

[0116] If the inter-terminal voltage of the capacitor C1 acquired in step S21 is equal to or higher than the normal minimum inter-terminal voltage (step S23; No), the process of step S24 is not performed.

[0117] When the emergency running signal is at H level, that is, when the vehicle is running in an emergency (step S22; Yes), the protection determination unit 47 determines whether or not the terminal voltage of the capacitor C1 acquired in step S21 is less than the minimum terminal voltage in emergency, which is the lower limit of the terminal voltage of the capacitor C1 required to drive the motor 91 in an emergency running (step S25). The minimum terminal voltage in emergency is set lower than the normal minimum terminal voltage.

[0118] If the terminal voltage of capacitor C1 acquired in step S21 is less than the minimum terminal voltage in an emergency (step S25; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S26).

[0119] If the terminal voltage of the capacitor C1 acquired in step S21 is equal to or higher than the minimum terminal voltage in an emergency (step S25; No), the process of step S26 is not performed.

[0120] The protection determination unit 47 repeats the above-mentioned process while the inverter 12 is operating under the control of the switching control unit 46.

[0121] Another example of the protection operation of the inverter 12 of the first power conversion device 10 performed by the conversion control device 40 will be described with reference to Fig. 15. When the inverter 12 starts operating under the control of the switching control unit 46, the protection determination unit 47 starts the processing of the protection operation shown in Fig. 15.

[0122] The protection determiner 47 acquires a measurement value of the voltage sensor PT1 indicating the value of the voltage applied to the first power converter 10 and a measurement value of the voltage sensor PT2 indicating the value of the voltage between the terminals of the capacitor C1 (step S31). The protection determiner 47 calculates the absolute value of the voltage difference between the voltage applied to the first power converter 10 and the voltage between the terminals of the capacitor C1 (step S32).

[0123] When the emergency running signal is at L level, i.e., when emergency running is not in progress (step S33; No), the protection judgment unit 47 judges whether the absolute value of the voltage difference calculated in step S32 is greater than the normal maximum voltage difference, which is the upper limit of the absolute value of the voltage difference between the applied voltage and the terminal voltage that can drive the motor 91 when power is supplied from the main power source 92 to the first power conversion device 10 (step S34).

[0124] When the absolute value of the voltage difference calculated in step S32 is greater than the normal maximum voltage difference (step S34; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S35).

[0125] If the absolute value of the voltage difference calculated in step S32 is equal to or less than the normal maximum voltage difference (step S34; No), the process of step S35 is not performed.

[0126] When the emergency running signal is at H level, that is, when the vehicle is running in an emergency (step S33; Yes), the protection determination unit 47 determines whether or not the absolute value of the voltage difference calculated in step S32 is greater than the maximum emergency voltage difference, which is the upper limit of the absolute value of the voltage difference between the applied voltage and the terminal voltage that can drive the motor 91 in an emergency running (step S36). The maximum emergency voltage difference is set smaller than the normal minimum voltage difference.

[0127] When the absolute value of the voltage difference calculated in step S32 is greater than the maximum emergency voltage difference (step S36; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S37).

[0128] If the absolute value of the voltage difference calculated in step S32 is equal to or less than the maximum emergency voltage difference (step S36; No), the process of step S37 is not performed.

[0129] The protection determination unit 47 repeats the above-mentioned process while the inverter 12 is operating under the control of the switching control unit 46.

[0130] Another example of the protection operation of the inverter 12 of the first power conversion device 10 performed by the conversion control device 40 will be described with reference to Fig. 16. When the inverter 12 starts operating under the control of the switching control unit 46, the protection determination unit 47 starts the processing of the protection operation shown in Fig. 16.

[0131] The protection determination unit 47 acquires a measurement value of the current sensor CT1 that measures the value of the current flowing through the first power conversion device 10 (step S41). When the emergency running signal is at L level, that is, when emergency running is not in progress (step S42; No), the protection determination unit 47 determines whether or not the measurement value of the current sensor CT1 acquired in step S41 is greater than a normal maximum current that is an upper limit of the absolute value of the current flowing through the first power conversion device 10 when power is supplied from the main power source 92 to the first power conversion device 10 (step S43).

[0132] When the absolute value of the current acquired in step S41 is greater than the normal maximum current (step S43; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S44).

[0133] If the absolute value of the current acquired in step S41 is equal to or less than the normal maximum current (step S43; No), the process of step S44 is not performed.

[0134] When the emergency running signal is at H level, that is, when the vehicle is running in an emergency (step S42; Yes), the protection determination unit 47 determines whether or not the measured current value acquired in step S41 is greater than the maximum emergency current, which is the upper limit of the current flowing through the first power conversion device 10 during emergency running (step S45). The maximum emergency current is set smaller than the normal minimum current.

[0135] When the measured current value acquired in step S41 is greater than the maximum emergency current (step S45; Yes), the protection determination unit 47 determines that protection of the inverter 12 is necessary, and sends a signal instructing protection to the switching control unit 46 and the changeover control unit 32 (step S46).

[0136] If the measured current value acquired in step S41 is equal to or less than the maximum emergency current (step S45; No), the process of step S46 is not performed.

[0137] The protection determination unit 47 repeats the above-mentioned process while the inverter 12 is operating under the control of the switching control unit 46.

[0138] 13 to 16, the switching control unit 46 acquires a signal instructing protection as a result of the protection operation of the protection determining unit 47, and turns off each switching element of the inverter 12. As a result, the first power conversion device 10 stops.

[0139] When the first power conversion device 10 and the low-voltage storage device 20 are electrically connected and a protection operation for stopping the first power conversion device 10 is performed as described above, the switching control unit 32 electrically disconnects the first power conversion device 10 and the low-voltage storage device 20. In detail, when the switching control unit 32 acquires a signal instructing protection, if the first contactor LS1 and the second contactor LS2 are closed, the switching control unit 32 opens the first contactor LS1 and the second contactor LS2. This disconnects the first battery module 21 of the low-voltage storage device 20 from the first power conversion device 10, and the occurrence of abnormalities such as overcurrent and overvoltage in the first battery module 21 of the low-voltage storage device 20 when an abnormality occurs in the first power conversion device 10 is suppressed.

[0140] The protection determination unit 47 of the second control unit 42 performs the same processing as the protection determination unit 47 of the first control unit 41. However, since the second power conversion device 50 stops operating during emergency running, the protection determination unit 47 of the second control unit 42 does not perform the operations during emergency running in Fig. 13 to Fig. 16, specifically, steps S15 and S16 in Fig. 13, steps S25 and S26 in Fig. 14, steps S36 and S37 in Fig. 15, and steps S45 and S46 in Fig. 16.

[0141] When the second power conversion device 50 and the low-voltage storage device 20 are electrically connected and a protection operation for stopping the second power conversion device 50 is performed as described above, the switching control unit 32 electrically disconnects the second power conversion device 50 and the low-voltage storage device 20. In detail, when the switching control unit 32 acquires a signal instructing protection, if the third contactor LS3 and the fourth contactor LS4 are closed, the switching control unit 32 opens the third contactor LS3 and the fourth contactor LS4. This disconnects the first battery module 21 of the low-voltage storage device 20 from the second power conversion device 50, and the occurrence of an abnormality such as an overcurrent or an overvoltage in the first battery module 21 of the low-voltage storage device 20 when an abnormality occurs in the second power conversion device 50 is suppressed.

[0142] As described above, the drive control device 1 according to the second embodiment performs a protection operation for the inverter 12 included in the first power conversion device 10 both when power is supplied from the main power supply 92 to the first power conversion device 10 and when power is supplied from the low-voltage storage device 20 to the first power conversion device 10. Similarly, the drive control device 1 performs a protection operation for the inverter 12 of the D / A conversion circuit 51 included in the second power conversion device 50 when power is supplied from the main power supply 92 to the first power conversion device 10 and the second power conversion device 50. This makes it possible to protect the inverter 12 when an abnormality occurs in the inverter 12.

[0143] The present disclosure is not limited to the above-described embodiment. The above-described circuit configuration is an example. As an example, the switching circuit 31 may have only one of the first contactor LS1 and the second contactor LS2. Similarly, the switching circuit 31 may have only one of the third contactor LS3 and the fourth contactor LS4.

[0144] The circuit configuration of the inrush suppression circuit 11 is not limited to the above example. The main contactor LB and the charging contactor CHB may be connected in series, and a charging resistor CHR may be provided in parallel with the charging contactor CHB. In this case, the contactor control unit 44 may close both the main contactor LB and the charging contactor CHB, and then open the charging contactor CHB when the capacitor C1 is sufficiently charged.

[0145] The drive control device 1 may be mounted on an AC-powered railway vehicle. When mounted on an AC-powered railway vehicle, the drive control device 1 may be supplied with DC power that is collected by a current collector, stepped down by a high-voltage transformer, and converted by a converter. In this case, instead of the high-speed circuit breaker HB provided in the first power conversion device 10, a high-speed circuit breaker may be provided between the primary winding of the high-voltage transformer and the current collector.

[0146] The control of the first power converter 10 and the second power converter 50 by the first control unit 41 and the second control unit 42 is not limited to the above example. As an example, when the emergency running signal S2 becomes H level, the contactor control unit 44 may open the main contactor LB and then the circuit breaker control unit 43 may open the high-speed circuit breaker HB, or the circuit breaker control unit 43 may open the high-speed circuit breaker HB and then the contactor control unit 44 may open the main contactor LB. Alternatively, when the emergency running signal S2 becomes H level, the circuit breaker control unit 43 and the contactor control unit 44 may open the high-speed circuit breaker HB and the main contactor LB at the same timing.

[0147] A contactor may be provided between the second battery module 22 and the connection point of the second power conversion device 50 and the conversion control device 40, and the contactor may be turned on when the second battery module 22 is used as a power source for the conversion control device 40, such as when starting a railway vehicle.

[0148] The circuit configuration of the switching circuit 31 is not limited to the above example. As an example, a line breaker, a semiconductor element, or the like may be provided instead of the first contactor LS1, the second contactor LS2, the third contactor LS3, and the fourth contactor LS4.

[0149] The control of the switching circuit 31 by the switching control unit 32 is not limited to the above example. As an example, at time T12 after the emergency run signal becomes H level at time T11 in Fig. 8, the switching control unit 32 may simultaneously close the first contactor LS1 and the second contactor LS2 and open the third contactor LS3 and the fourth contactor LS4.

[0150] The position where the current sensor CT1 is provided is not limited to the above example. The current sensor CT1 is provided at any position where the value of the current flowing through the first power conversion device 10 can be measured both when power is supplied to the first power conversion device 10 from the main power supply 92 and when power is supplied to the first power conversion device 10 from the low-voltage storage device 20. As an example, the current sensor CT1 may be provided between the output side of the inrush suppression circuit 11 and the reactor L1.

[0151] The hardware configuration of the switching control unit 32 and the conversion control device 40 is not limited to the above example. A modified example of the hardware configuration of the switching control unit 32 and the conversion control device 40 is shown in FIG. 17. As shown in FIG. 17, the switching control unit 32 and the conversion control device 40 may be realized by a processing circuit 84. The switching control unit 32 is connected to the first contactor LS1, the second contactor LS2, the third contactor LS3, the fourth contactor LS4, and the voltage sensor PT2 via an interface circuit 85. The conversion control device 40 is connected to the high-speed circuit breaker HB, the main contactor LB, the charging contactor CHB, the discharge switch OVT, the inverter 12, the voltage sensors PT1 and PT2, and the current sensor CT1 via the interface circuit 85.

[0152] When the processing circuit 84 is a dedicated hardware, the processing circuit 84 has, for example, a single circuit, a composite circuit, a processor, an ASIC (Application Specific Integrated Circuit), an FPGA (Field Programmable Gate Array), or a combination of these. Each part of the switching control unit 32 and the conversion control device 40 may be realized by an individual processing circuit 84 or may be realized by a common processing circuit 84.

[0153] Some of the functions of the switching control unit 32 and the conversion control device 40 may be realized by dedicated hardware, and the other parts may be realized by software or firmware. For example, in the first control unit 41 of the conversion control device 40 included in the drive control device 1 according to the first embodiment, the breaker control unit 43 and the contactor control unit 44 may be realized by a processing circuit 84 shown in Fig. 17, and the discharge control unit 45 and the switching control unit 46 may be realized by a processor 81 shown in Fig. 5 reading and executing a program stored in a memory 82.

[0154] At least a part of the switching control unit 32 and the conversion control device 40 may be realized as one function of a train information management system. The start signal S1 and the emergency run signal S2 may be supplied to the switching control unit 32 and the conversion control device 40 from the train information management system.

[0155] The drive control device 1 is not limited to being mounted on a railway vehicle, and may be mounted on any moving object that runs on power supplied from an external source, such as a trolley bus. Various aspects of the present disclosure are summarized below as appendices. (Appendix 1) a first power conversion device that converts supplied electric power into electric power to be supplied to an electric motor that generates a propulsive force for the railway vehicle and supplies the converted electric power to the electric motor; and a switching circuit that is connected to a low-voltage storage device that discharges at a voltage lower than a voltage applied to the first power conversion device when electric power is supplied from a main power source to the first power conversion device, and that forms an electric path between the first power conversion device and the low-voltage storage device. a switching control unit that, when power is supplied from the main power source to the first power conversion device, controls the switching circuit to electrically disconnect the first power conversion device and the low-voltage storage device from each other, and, when the supply of power from the main power source to the first power conversion device is stopped while the railway vehicle is started, controls the switching circuit to electrically connect the first power conversion device and the low-voltage storage device to each other; A power supply switching device comprising: (Appendix 2) the switching circuit has at least one power supply contactor electrically connected to the first power conversion device and the low-voltage power storage device; the switching control unit opens the power supply contactor when power is supplied from the main power source to the first power conversion device, and closes the power supply contactor when the supply of power from the main power source to the first power conversion device is stopped while the railcar is started. 2. A power supply switching device as described in claim 1. (Appendix 3) the at least one power supply contactor includes a first contactor having one end connected to a positive input terminal that is a positive terminal on the main power supply side of the first power conversion device and the other end connected to a positive battery terminal of a first battery module included in the low-voltage power storage device; 3. A power supply switching device as described in appended claim 2. (Appendix 4) the at least one power supply contactor further includes a second contactor having one end connected to a negative input terminal that is a negative terminal of the first power conversion device on the main power supply side and the other end connected to a negative battery terminal of the first battery module; 4. A power supply switching device as described in appended claim 3. (Appendix 5) the switching circuit is electrically connected to the first power conversion device, the low-voltage storage device, and a second power conversion device that converts power supplied from the main power supply into power to be supplied to a conversion control device that controls the first power conversion device and outputs the converted power to the conversion control device and the low-voltage storage device, and forms an electric path between the first power conversion device and the low-voltage storage device, and an electric path between the second power conversion device and the low-voltage storage device; the switching control unit electrically connects the second power conversion device and the low-voltage storage device to each other when power is supplied from the main power source to the first power conversion device, and electrically disconnects the second power conversion device and the low-voltage storage device from each other when the supply of power from the main power source to the first power conversion device is stopped while the railway vehicle is started. 5. A power supply switching device according to any one of claims 1 to 4. (Appendix 6) the switching circuit further includes at least one charging contactor electrically connected to the second power conversion device and the low-voltage storage device; the switching control unit closes the charging contactor when power is supplied from the main power source to the first power conversion device, and opens the charging contactor when the supply of power from the main power source to the first power conversion device stops while the railcar is started. 6. A power supply switching device as described in appended claim 5. (Appendix 7) the at least one charging contactor includes a third contactor having one end connected to a positive output terminal that is a positive terminal on the output side of the second power conversion device and the other end connected to a positive battery terminal of a first battery module of the low-voltage storage device; 7. A power supply switching device as claimed in claim 6. (Appendix 8) the at least one charging contactor further includes a fourth contactor having one end connected to a negative output terminal that is a negative terminal of the output side of the second power conversion device and the other end connected to a negative battery terminal of the first battery module; 8. The power supply switching device according to claim 7. (Appendix 9) The switching circuit further includes a fuse provided in an electric path between the first power conversion device and the low-voltage storage device. 9. A power supply switching device according to any one of claims 1 to 8. (Appendix 10) A power supply switching device according to any one of appendix 1 to 9; a first power conversion device that converts supplied electric power into electric power to be supplied to an electric motor that generates a propulsive force for the railway vehicle, supplies the converted electric power to the electric motor, and is connected to the power source switching device; a conversion control device that controls the first power conversion device by sending pulse width modulation signals to a plurality of switching elements included in the first power conversion device; a low-voltage power storage device that supplies power to the conversion control device, discharges at a voltage lower than a voltage applied to the first power conversion device when power is supplied from a main power source to the first power conversion device, and is connected to the power source switching device; When the first power conversion device and the low-voltage storage device are electrically connected to each other by the power source switching device, the conversion control device sends, to each of the multiple switching elements of the first power conversion device, a pulse width modulation signal having a modulation rate higher than that when the first power conversion device and the low-voltage storage device are electrically separated from each other and power is supplied to the first power conversion device from the main power source. Drive control device. (Appendix 11) the low-voltage storage device has a first battery module that is electrically connected to the first power conversion device or electrically disconnected from the first power conversion device by the switching control unit controlling the switching circuit, and when the first battery module is electrically connected to the first power conversion device, the low-voltage storage device supplies power stored in the first battery module to the first power conversion device. 11. The drive control device according to claim 10. (Appendix 12) the first power conversion device includes a capacitor that is charged with power supplied from the main power supply or the low-voltage storage device, and a discharge circuit that has a discharge resistor and a discharge switch connected in series to each other and is connected in parallel to the capacitor; when the supply of power from the main power source to the first power conversion device is stopped while the railway vehicle is started, if the terminal voltage of the capacitor is higher than an emergency maximum terminal voltage that is set lower than the discharge voltage of the low-voltage power storage device, the conversion control device turns on the discharge switch to electrically connect the capacitor to the discharge resistor, thereby discharging the capacitor; the switching control unit controls the switching circuit after the capacitor is discharged to electrically connect the first power conversion device and the low-voltage storage device to each other. 12. The drive control device according to claim 11. (Appendix 13) when power is supplied from the low-voltage storage device to the first power conversion device, if the terminal voltage of the capacitor becomes equal to or lower than a minimum terminal voltage in an emergency, the minimum terminal voltage being set lower than a lower limit value of the terminal voltage necessary to drive the electric motor when power is supplied from the main power source to the first power conversion device, the conversion control device performs a protective operation to stop the first power conversion device. 13. The drive control device according to claim 12. (Appendix 14) When an absolute value of a difference between a voltage applied to the first power conversion device and a terminal voltage of the capacitor becomes larger than a maximum emergency voltage difference that is set smaller than an upper limit of an absolute value of a voltage difference between the applied voltage and the terminal voltage that allows the electric motor to be driven when power is supplied from the main power source to the first power conversion device, the conversion control device performs a protective operation to stop the first power conversion device. 14. The drive control device according to claim 12 or 13. (Appendix 15) a second power conversion device that is controlled by the conversion control device to convert power supplied from the main power supply into power to be supplied to the conversion control device and output the converted power to the conversion control device and the low-voltage power storage device; the switching circuit of the power supply switching device is electrically connected to the first power conversion device, the low-voltage storage device, and the second power conversion device, and forms an electric path between the first power conversion device and the low-voltage storage device, and an electric path between the second power conversion device and the low-voltage storage device; The low-voltage power storage device is charged with the power output by the second power conversion device. 15. A drive control device according to any one of claims 10 to 14. (Appendix 16) the low-voltage power storage device includes a second battery module having both ends connected to a positive power supply terminal and a negative power supply terminal of the conversion control device; the low-voltage power storage device supplies the power stored in the second battery module to the conversion control device when the supply of power from the second power conversion device to the conversion control device is stopped; 16. The drive control device according to claim 15. (Appendix 17) the conversion control device performs a protective operation to stop the first power conversion device when a voltage applied to the first power conversion device when power is supplied from the low-voltage storage device to the first power conversion device becomes equal to or lower than an emergency minimum applied voltage that is set lower than a lower limit value of the applied voltage necessary to drive the electric motor when power is supplied from the main power source to the first power conversion device, 17. A drive control device according to any one of appendix 10 to 16. (Appendix 18) the conversion control device performs a protective operation to stop the first power conversion device when an absolute value of a current flowing through the first power conversion device becomes equal to or greater than an emergency maximum current that is set to be smaller than an upper limit value of a current flowing into the first power conversion device when power is supplied from the main power source to the first power conversion device, while power is being supplied from the low-voltage storage device to the first power conversion device; 18. A drive control device according to any one of appendixes 10 to 17. (Appendix 19) When a protection operation is performed by the conversion control device in a state in which the first power conversion device and the low-voltage storage device are electrically connected, the switching control unit electrically disconnects the first power conversion device and the low-voltage storage device. 19. A drive control device according to any one of appendixes 13, 14, 17 and 18.

[0156] Various embodiments and modifications of the present disclosure are possible without departing from the broad spirit and scope of the present disclosure. The above-described embodiments are for explaining the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is indicated by the claims, not the embodiments. Various modifications made within the scope of the claims and the scope of the disclosure equivalent thereto are considered to be within the scope of the present disclosure. [Explanation of symbols]

[0157] 1 Drive control device, 10 First power conversion device, 10a Positive input terminal, 10b Negative input terminal, 11 Inrush suppression circuit, 12 Inverter, 13 Discharge circuit, 20 Low-voltage storage device, 21 First battery module, 21a Positive battery terminal, 21b Negative battery terminal, 22 Second battery module, 30 Power supply switching device, 31 Switching circuit, 32 Switching control unit, 40 Conversion control device, 41 First control unit, 42 Second control unit, 43 Circuit breaker control unit, 44 Contactor control unit, 45 Discharge control unit, 46 Switching control unit, 47 Protection determination unit, 50 Second power conversion device, 51 D / A conversion circuit, 52 Rectifier circuit, 80 Bus, 81 Processor, 82 Memory, 83 Interface, 84 Processing circuit, 85 Interface circuit, 91 Motor, 92 Main power source, 93 Load device, ACC1 AC capacitor, BTF Fuse, C1 capacitor, CHB charging contactor, CHR charging resistor, CT1 current sensor, HB high speed circuit breaker, LB main contactor, LS1 first contactor, LS2 second contactor, LS3 third contactor, LS4 fourth contactor, OVR discharge resistor, OVT discharge switch, PT1, PT2 voltage sensors, S1 start signal, S2 emergency run signal, TR1 transformer.

Claims

1. A main power source that acquires power from an external source; a first power conversion device that converts power supplied from the main power supply into power to be supplied to an electric motor that generates a propulsive force of the moving body, and supplies the converted power to the electric motor; one or more low-voltage power storage devices that are charged by a second power conversion device connected to the main power supply and that converts power supplied from the main power supply into low-voltage DC power and outputs the low-voltage DC power, and that discharge at a voltage lower than the voltage applied from the main power supply to the first power conversion device; a power supply switching device connected to the first power conversion device and the low-voltage storage device, forming an electric path between the first power conversion device and the low-voltage storage device, and electrically connecting the first power conversion device and the low-voltage storage device to each other when the supply of power from the main power supply is stopped; A mobile body comprising:

2. The total voltage of the one or more low-voltage storage devices is 10% or more and 20% or less of the voltage applied from the main power source to the first power conversion device. The moving body according to claim 1 .

3. The power supply switching device acquires an emergency running signal that instructs the vehicle to run in an emergency using the power stored in the low-voltage storage device when the power supply from the main power source is stopped, and controls the first power conversion device and the low-voltage storage device to be electrically connected to or electrically disconnected from each other based on the emergency running signal.

3. A moving body according to claim 1 or 2.

4. The power supply switching device receives the emergency running signal, and when the capacitors of the first power conversion device and the second power conversion device are discharged and no current flows through the first power conversion device and the second power conversion device, electrically connects the first power conversion device and the low-voltage storage device to each other. The moving body according to claim 3 .

Images