Drive control apparatus

Abstract

A drive control apparatus (1) for controlling the driving of a railway vehicle that uses a plurality of internal combustion engines (91a, 91b) as a motive power source comprises: a plurality of converters (11a, 11b) which are provided so as to correspond to the internal combustion engines (91a, 91b); a plurality of first inverters (12a, 12b) which are respectively provided for the converters (11a, 11b); and at least one power storage device (13a, 31b) which is connected to the converters (11a, 11b) and the first inverters (12a, 12b). When starting the internal combustion engines (91a, 91b), a first inverter (12a, 12b) connected to a converter (11a, 11b) not being supplied with DC power receives supply of AC power from a first inverter (12a, 12b) connected to a power storage device (13a, 13b) in which the amount of power stored therein is greater than the amount of power for starting the internal combustion engines (91a, 91b), and converts the AC power to DC power and outputs the DC power from a primary terminal (21a, 21b).

Description

Drive control device

[0001] The present disclosure relates to a drive control device.

[0002] Some railway vehicles are powered by an internal combustion engine. An example of this type of railway vehicle is disclosed in Patent Document 1. The railway vehicle disclosed in Patent Document 1 includes an engine, a generator driven by the engine to generate AC power, a converter that converts the AC power generated by the generator into DC power, an inverter that converts the DC power supplied from the converter into AC power, an electric motor that rotates by receiving AC power from the inverter, and a drive control device that controls the converter and the inverter.

[0003] International Publication No. 2019 / 73822

[0004] In order to start the engine of the above-mentioned railway vehicle, it is necessary to supply power to a generator, operate the generator as an electric motor, and transmit rotational force from the generator operating as an electric motor to the engine. To supply power to the generator, an electric storage device capable of storing the electric power required to start the engine is provided. A converter converts DC power supplied from the electric storage device into AC power, and supplies the converted AC power to the generator, causing the generator to operate and rotate as an electric motor. The rotation of the generator starts the engine.

[0005] If the supply of DC power to the converter is stopped when the engine is started due to discharge of the power storage device, a malfunction, or disconnection of the power storage device from the converter, the engine cannot be started.

[0006] The present disclosure has been made in consideration of the above-mentioned circumstances, and aims to provide a drive control device that enables starting of an internal combustion engine when the supply of DC power to a part of a converter connected to the internal combustion engine via a generator is stopped.

[0007] To achieve the above object, a traction control device disclosed herein controls the traction of a railway vehicle powered by multiple internal combustion engines, and includes multiple converters, multiple first inverters, and at least one power storage device. The converter is provided for each generator corresponding to an internal combustion engine, which generates AC power when driven by the internal combustion engine, and performs bidirectional conversion between AC power and DC power. The first inverter is provided for each converter, and has a primary terminal connected to the converter and a secondary terminal connected to a load device that operates by receiving AC power, and performs bidirectional conversion between DC power and AC power. The power storage device has a storage capacity greater than the starting power amount of the internal combustion engines, is connected to the converter and the primary terminal of the corresponding first inverter, and is charged with DC power output by the converter or the first inverter. The secondary terminals of the multiple first inverters are connected to each other. When starting the multiple internal combustion engines, the converter, which receives DC power for starting the internal combustion engines, converts the DC power into AC power and supplies the converted AC power to the generator. When starting a plurality of internal combustion engines, a first inverter connected to a converter that is not supplied with DC power for starting the internal combustion engines receives AC power generated by a first inverter connected to a power storage device having a stored amount of power greater than the startup power amount by converting DC power supplied from the power storage device, converts the supplied AC power into DC power, and outputs the converted DC power from a primary terminal.

[0008] In the drive control device disclosed herein, when starting multiple internal combustion engines, a first inverter connected to a converter that does not receive DC power for starting the internal combustion engines converts AC power supplied from a first inverter connected to a power storage device with a stored amount of power greater than the startup power amount into DC power and outputs the converted DC power from its primary terminals. As a result, each converter receives DC power, converts the DC power into AC power, and supplies the converted AC power to a generator. This provides a drive control device that enables starting of internal combustion engines even when DC power supply to some of the converters is stopped.

[0009] FIG. 1 is a block diagram showing the configuration of a drive control device according to embodiment 1; FIG. 2 is a block diagram showing the configuration of a first inverter according to embodiment 1; FIG. 3 is a block diagram showing the configuration of a control unit according to embodiment 1; FIG. 4 is a block diagram showing the hardware configuration of a control unit according to embodiment 1; FIG. 1 is a timing chart showing an example of an operation of starting an internal combustion engine performed by the drive control device; FIG. 2 is a diagram showing an example of a current flow in the drive control device according to a third embodiment; FIG. 3 is a block diagram showing the configuration of a first modified example of the drive control device according to the embodiment; FIG. 4 is a block diagram showing the configuration of a second modified example of the drive control device according to the embodiment; FIG. 5 is a timing chart showing an example of an operation of starting an internal combustion engine performed by the second modified example of the drive control device according to the embodiment; FIG. 6 is a timing chart showing another example of an operation of starting an internal combustion engine performed by the drive control device in a state where some of the charging devices are discharged;

[0010] Hereinafter, a drive control device according to an embodiment of the present disclosure will be described in detail with reference to the drawings, in which the same or equivalent parts are designated by the same reference numerals.

[0011] (Embodiment 1) A drive control device for controlling the drive of a railway vehicle will be described using a railway vehicle powered by multiple internal combustion engines as an example. Fig. 1 shows a railway vehicle drive device 100 for driving a railway vehicle made up of multiple cars 100a, 100b.

[0012] The railway vehicle drive system 100 includes internal combustion engines 91a, 91b that are the power sources of the railway vehicle, generators 92a, 92b that generate AC power when driven by the internal combustion engines 91a, 91b, a drive control device 1 that controls the drive of the railway vehicle by supplying the power generated by the generators 92a, 92b to traction motors 93a, 93b, and traction motors 93a, 93b that generate propulsion power for the railway vehicle by rotating upon receiving AC power from the drive control device 1. Load devices 94a, 94b mounted on the vehicles 100a, 100b, respectively, operate upon receiving power supply from the drive control device 1.

[0013] The drive control device 1 has a main conversion device 1a that converts AC power supplied from a generator 92a into AC power suitable for each of the main motor 93a and the load device 94a, and supplies the converted AC power to the main motor 93a and the load device 94a, and a main conversion device 1b that converts AC power supplied from a generator 92b into AC power suitable for each of the main motor 93b and the load device 94b, and supplies the converted AC power to the main motor 93b and the load device 94b.

[0014] The internal combustion engine 91a, generator 92a, main converter 1a, traction motor 93a, and load device 94a are mounted on a vehicle 100a. The internal combustion engine 91b, generator 92b, main converter 1b, traction motor 93b, and load device 94b are mounted on a vehicle 100b.

[0015] The internal combustion engines 91a, 91b are diesel engines, gasoline engines, or the like. The output shafts of the internal combustion engines 91a, 91b are fixed to the shafts of generators 92a, 92b, respectively. As a result, when the railway vehicle begins operation, the generators 92a, 92b are operated as electric motors to rotate, thereby starting the internal combustion engines 91a, 91b. After the internal combustion engines 91a, 91b start, the generators 92a, 92b rotate in conjunction with the rotation of the internal combustion engines 91a, 91b, generating AC power. The rotation speeds of the internal combustion engines 91a, 91b are controlled by an internal combustion engine control unit (not shown).

[0016] The internal combustion engine control unit acquires a start command signal that changes in response to operation of a start switch provided in the cab, an operation command signal that changes in response to operation of a master controller provided in the cab, and the rotation speeds of the internal combustion engines 91 a, 91 b measured by a speed sensor (not shown). The internal combustion engine control unit determines a target rotation speed based on the start command signal, the operation command signal, and the measured values ​​of the rotation speeds of the internal combustion engines 91 a, 91 b, and performs control to bring the rotation speeds of the internal combustion engines 91 a, 91 b closer to the target rotation speed.

[0017] When the internal combustion engines 91a, 91b have not started, the generators 92a, 92b each operate as an electric motor and rotate when supplied with AC power from the drive control device 1. After the internal combustion engines 91a, 91b have started, the generators 92a, 92b are driven by the internal combustion engines 91a, 91b, respectively, to generate AC power and supply the generated AC power to the drive control device 1. The generators 92a, 92b are, for example, induction generators.

[0018] The traction motors 93a, 93b are each driven by AC power supplied from the drive control device 1, and generate propulsion force for the railway vehicle. To avoid complicating the diagram, FIG. 1 shows only one traction motor 93a, 93b, but each of the vehicles 100a, 100b is equipped with multiple traction motors. Specifically, the vehicle 100a is equipped with multiple traction motors 93a, for example, four traction motors 93a. The vehicle 100b is equipped with multiple traction motors 93b, for example, four traction motors 93b. The traction motors 93a, 93b are, for example, three-phase induction motors.

[0019] The load devices 94a and 94b are in-vehicle devices that operate by receiving AC power from the drive control device 1, such as lighting equipment and air conditioning equipment.

[0020] The drive control device 1 includes multiple converters 11a, 11b, each of which is provided for a generator 92a, 92b corresponding to the internal combustion engine 91a, 91b, and which perform bidirectional conversion between AC and DC power. Also included are multiple first inverters 12a, 12b, each of which is provided for each converter 11a, 11b, and which perform bidirectional conversion between DC and AC power. The drive control device 1 also includes at least one power storage device (two power storage devices 13a, 13b in the example of FIG. 1 ) with a storage capacity greater than the starting power requirement of the internal combustion engine 91a or the internal combustion engine 91b. The starting power requirement of the internal combustion engine 91a is the amount of power required by the converter 11a, which supplies AC power to the generator 92a to start the internal combustion engine 91a. The same applies to the starting power requirement of the internal combustion engine 91b. The drive control device 1 also includes second inverters 14a, 14b, each of which is provided for each converter 11a, 11b.

[0021] When starting the internal combustion engines 91a, 91b, if one of the converters 11a, 11b is not supplied with DC power for starting the internal combustion engines 91a, 91b, one of the first inverters 12a, 12b receives AC power from the other of the first inverters 12a, 12b, converts the supplied AC power into DC power, and outputs the converted DC power. This makes it possible to start both of the internal combustion engines 91a, 91b even if one of the converters 11a, 11b is not supplied with DC power when starting the internal combustion engines 91a, 91b.

[0022] The converter 11a, first inverter 12a, power storage device 13a, and second inverter 14a are included in the main conversion device 1a. In addition to the above components, the main conversion device 1a also includes a transformer 16a, the primary terminal of which is connected to the first inverter 12a, that transforms the AC power output from the first inverter 12a to convert the AC power into power suitable for the load device 94a, and an AC capacitor 17a connected to the secondary terminal of the transformer 16a. "Connection" refers to being electrically connected. The main conversion device 1a also includes a power storage device contactor 18a that switches the electrical connection between the power storage device 13a and the converter 11a, the first inverter 12a, and the second inverter 14a, and an inverter contactor 19a, one end of which is connected to the connection point between the AC capacitor 17a and the load device 94a. The main conversion device 1a includes a control unit 15a that controls the above-mentioned converter 11a, first inverter 12a, second inverter 14a, power storage device contactor 18a, and inverter contactor 19a.

[0023] The above-described converter 11b, first inverter 12b, power storage device 13b, and second inverter 14b are included in main conversion unit 1b. In addition to the above components, main conversion unit 1b also includes a transformer 16b, to which first inverter 12b is connected at its primary terminals, that transforms the AC power output by first inverter 12b to make the AC power suitable for load device 94b, and an AC capacitor 17b connected at its secondary terminals. Main conversion unit 1b also includes a power storage device contactor 18b that switches the electrical connection between power storage device 13b and converter 11b, first inverter 12b, and second inverter 14b, and an inverter contactor 19b whose one end is connected to the connection point between AC capacitor 17b and load device 94b. The main conversion device 1b includes a control unit 15b that controls the converter 11b, the first inverter 12b, the second inverter 14b, the power storage device contactor 18b, and the inverter contactor 19b.

[0024] Converter 11a is connected to a generator 92a driven by an internal combustion engine 91a, and converter 11b is connected to a generator 92b driven by an internal combustion engine 91b. Specifically, an AC side terminal of converter 11a is connected to the output terminal of generator 92a, and a DC side terminal of converter 11a is connected to the first inverter 12a, the power storage device 13a, and the second inverter 14a. An AC side terminal of converter 11b is connected to the output terminal of generator 92b, and a DC side terminal of converter 11b is connected to the first inverter 12b, the power storage device 13b, and the second inverter 14b.

[0025] Each of the converters 11a and 11b includes a capacitor and a plurality of switching elements connected in parallel to the capacitor. The plurality of switching elements of the converters 11a and 11b are controlled by the control units 15a and 15b, respectively, so that the converters 11a and 11b convert supplied AC power into DC power or convert supplied DC power into AC power. When the internal combustion engines 91a and 91b are started, the converters 11a and 11b receive DC power for starting the internal combustion engines 91a and 91b, convert the DC power into AC power, and supply the converted AC power to the generators 92a and 92b.

[0026] The first inverters 12a and 12b are, for example, static inverters that maintain constant output voltage and output frequency. The first inverter 12a has primary terminals 21a and 22a, which are DC side terminals connected to the converter 11a, and secondary terminals 23a, 24a, and 25a, which are AC side terminals connected to a load device 94a via a transformer 16a and an AC capacitor 17a. The first inverter 12b has primary terminals 21b and 22b, which are DC side terminals connected to the converter 11b, and secondary terminals 23b, 24b, and 25b, which are AC side terminals connected to a load device 94b via a transformer 16b and an AC capacitor 17b. The secondary terminals 23a, 24a, and 25a of the first inverter 12a are connected to the secondary terminals 23b, 24b, and 25b of the first inverter 12b via inverter contactors 19a and 19b, respectively.

[0027] 2, the first inverter 12a includes a capacitor C1 having both terminals connected to the primary terminals 21a and 22a, switching elements SW1 and SW2 connected in series between the primary terminals 21a and 22a, switching elements SW3 and SW4 connected in series between the primary terminals 21a and 22a, and switching elements SW5 and SW6 connected in series between the primary terminals 21a and 22a.

[0028] Switching elements SW1 and SW2, switching elements SW3 and SW4, and switching elements SW5 and SW6 correspond to the U phase, V phase, and W phase, respectively. The connection point of switching elements SW1 and SW2 is connected to secondary terminal 23a. The connection point of switching elements SW3 and SW4 is connected to secondary terminal 24a. The connection point of switching elements SW5 and SW6 is connected to secondary terminal 25a. The multiple switching elements SW1 to SW6 of first inverters 12a and 12b are controlled by control units 15a and 15b, respectively, to be repeatedly turned on and off, thereby causing first inverters 12a and 12b to convert DC power to AC power.

[0029] The switching elements SW1, SW2, SW3, SW4, SW5, and SW6 are, for example, IGBTs (Insulated Gate Bipolar Transistors), GTOs (Gate Turn-Off Thyristors), MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), etc. In the example of Fig. 2, IGBTs are used as the switching elements SW1, SW2, SW3, SW4, SW5, and SW6.

[0030] The first inverter 12a has freewheeling diodes D1, D2, D3, D4, D5, and D6 connected in parallel to the switching elements SW1, SW2, SW3, SW4, SW5, and SW6, respectively.

[0031] The anode of the freewheeling diode D1 is connected to the emitter terminal of the switching element SW1, and the cathode of the freewheeling diode D1 is connected to the collector terminal of the switching element SW1. Similarly, the anode of the freewheeling diode D2 is connected to the emitter terminal of the switching element SW2, and the cathode of the freewheeling diode D2 is connected to the collector terminal of the switching element SW2.

[0032] Similarly, the anode of the freewheeling diode D3 is connected to the emitter terminal of the switching element SW3, and the cathode of the freewheeling diode D3 is connected to the collector terminal of the switching element SW3. Similarly, the anode of the freewheeling diode D4 is connected to the emitter terminal of the switching element SW4, and the cathode of the freewheeling diode D4 is connected to the collector terminal of the switching element SW4.

[0033] Similarly, the anode of the freewheeling diode D5 is connected to the emitter terminal of the switching element SW5, and the cathode of the freewheeling diode D5 is connected to the collector terminal of the switching element SW5. Similarly, the anode of the freewheeling diode D6 is connected to the emitter terminal of the switching element SW6, and the cathode of the freewheeling diode D6 is connected to the collector terminal of the switching element SW6.

[0034] The anodes of the freewheeling diodes D1, D3, and D5 are connected to the secondary terminals 23a, 24a, and 25a of the first inverter 12a, respectively. The cathodes of the freewheeling diodes D1, D3, and D5 are connected to the primary terminal 21a, which corresponds to the positive electrode of the primary terminals 21a and 21b of the first inverter 12a. The anodes of the freewheeling diodes D2, D4, and D6 are connected to the primary terminal 22a, which corresponds to the negative electrode of the primary terminals 21a and 21b of the first inverter 12a. The cathodes of the freewheeling diodes D2, D4, and D6 are connected to the secondary terminals 23a, 24a, and 25a of the first inverter 12a, respectively.

[0035] When AC power is supplied from the secondary terminals 23 a, 24 a, and 25 a while the switching elements SW1-SW6 are in the off state, the freewheeling diodes D1-D6 rectify the AC current flowing in from the secondary terminals 23 a, 24 a, and 25 a and output it from the primary terminal 21 a. As a result, the first inverter 12 a operates as a rectifier circuit that rectifies the AC power supplied from the secondary terminals 23 a, 24 a, and 25 a to convert it into DC power and output it from the primary terminals 21 a and 22 a.

[0036] As shown in Fig. 1, the power storage device 13a is connected to the converter 11a, the first inverter 12a, and the second inverter 14a. The power storage device 13a is charged with power output from the converter 11a, the first inverter 12a, or the second inverter 14a. Similarly, the power storage device 13b is connected to the converter 11b, the first inverter 12b, and the second inverter 14b. The power storage device 13b is charged with power output from the converter 11b, the first inverter 12b, or the second inverter 14b. Each of the power storage devices 13a and 13b includes a number of secondary batteries and a monitoring device that monitors the voltages between the terminals of the secondary batteries.

[0037] The DC side terminal of the second inverter 14a is connected to the converter 11a, the first inverter 12a, and the power storage device 13a, and the AC side terminal of the second inverter 14a is connected to the main motor 93a. Similarly, the DC side terminal of the second inverter 14b is connected to the converter 11b, the first inverter 12b, and the power storage device 13b, and the AC side terminal of the second inverter 14b is connected to the main motor 93b.

[0038] The second inverters 14a, 14b each include a capacitor that is charged with DC power output from the converters 11a, 11b, and multiple switching elements. The multiple switching elements of the second inverters 14a, 14b are controlled by control units 15a, 15b, respectively, so that the second inverters 14a, 14b convert DC power to AC power and supply the converted AC power to the main motors 93a, 93b. The second inverters 14a, 14b are formed, for example, by a power conversion circuit that is variable in output voltage and output frequency.

[0039] The transformers 16a, 16b are, for example, delta-star connected transformers that transform the AC power supplied from the first inverters 12a, 12b connected to the primary side to a voltage suitable for the load devices 94a, 94b and output the transformed AC power from the secondary side.

[0040] The AC capacitors 17a and 17b are connected to the secondary sides of the transformers 16a and 16b, respectively. The AC capacitors 17a and 17b form LC filters together with the coils of the transformers 16a and 16b, thereby reducing harmonic components generated by the switching operations of the first inverters 12a and 12b.

[0041] The power storage device contactors 18a and 18b electrically connect or disconnect the power storage devices 13a and 13b from other devices, respectively. Specifically, the main converter 1a has two power storage device contactors 18a connected to the positive and negative terminals of the power storage device 13a, respectively. When each power storage device contactor 18a is closed, the power storage device 13a is connected to the converter 11a, the first inverter 12a, and the second inverter 14a. When each power storage device contactor 18a is opened, the power storage device 13a is electrically disconnected from the converter 11a, the first inverter 12a, and the second inverter 14a.

[0042] The main converter 1b has two power storage device contactors 18b connected to the positive and negative terminals of the power storage device 13b, respectively. When each power storage device contactor 18b is closed, the power storage device 13b is connected to the converter 11b, the first inverter 12b, and the second inverter 14b. When each power storage device contactor 18b is opened, the power storage device 13b is electrically disconnected from the converter 11b, the first inverter 12b, and the second inverter 14b.

[0043] The inverter contactors 19a, 19b electrically connect or disconnect the first inverters 12a, 12b from each other. Specifically, the main converter 1a has three inverter contactors 19a corresponding to the U, V, and W phases, respectively. The main converter 1b has three inverter contactors 19b corresponding to the U, V, and W phases, respectively. The inverter contactors 19a, 19b corresponding to the same phase are electrically connected to each other.

[0044] When the inverter contactors 19a and 19b are turned on, the secondary terminals 23a, 24a, and 25a of the first inverter 12a are electrically connected to the secondary terminals 23b, 24b, and 25b of the first inverter 12b. Specifically, when the inverter contactors 19a and 19b are turned on, the secondary terminals of the transformers 16a and 16b are electrically connected to each other, thereby establishing electrical continuity between the secondary terminals 23a, 24a, and 25a of the first inverter 12a and the secondary terminals 23b, 24b, and 25b of the first inverter 12b.

[0045] When the inverter contactors 19 a and 19 b are opened, the secondary terminals 23 a, 24 a, and 25 a of the first inverter 12 a are electrically disconnected from the secondary terminals 23 b, 24 b, and 25 b of the first inverter 12 b. Specifically, when the inverter contactors 19 a and 19 b are opened, the secondary terminals of the transformers 16 a and 16 b are electrically disconnected from each other, and the secondary terminals 23 a, 24 a, and 25 a of the first inverter 12 a and the secondary terminals 23 b, 24 b, and 25 b of the first inverter 12 b are brought into a non-conductive state.

[0046] The control unit 15a controls the switching elements of the converter 11a, the switching elements SW1-SW6 of the first inverter 12a, the switching elements of the second inverter 14a, the power storage device contactor 18a, and the inverter contactor 19a. Similarly, the control unit 15b controls the switching elements of the converter 11b, the switching elements SW1-SW6 of the first inverter 12b, the switching elements of the second inverter 14b, the power storage device contactor 18b, and the inverter contactor 19b.

[0047] Since the control units 15a and 15b have similar configurations, only the configuration of the control unit 15a will be described. As shown in Fig. 3, the control unit 15a includes a first contactor control unit 31 that closes or opens the inverter contactor 19a, a second contactor control unit 32 that closes or opens the power storage device contactor 18a, and a power conversion control unit 33 that controls the converter 11a, the first inverter 12a, and the second inverter 14a. The control unit 15a also includes a start determination unit 34 that determines whether the converter 11a is supplied with DC power for starting the internal combustion engine 91a, for example, by using a DC voltage (hereinafter referred to as an intermediate link voltage) V1 applied to an electric circuit between the converter 11a and the first inverter 12a, and a charge determination unit 35 that determines whether the power storage device 13a is being charged, for example, based on the voltage of the power storage device 13a.

[0048] The first contactor control unit 31, the second contactor control unit 32, and the power conversion control unit 33 receive a start command signal S1 from the cab. The start command signal S1 is, for example, a signal that is at an L (low) level when the internal combustion engines 91 a, 91 b are stopped and is set to an H (high) level when the internal combustion engines 91 a, 91 b are started.

[0049] The power conversion control unit 33 receives a driving command signal S2 from the driver's cab. The driving command signal S2 is, for example, a signal indicating a powering notch that indicates the acceleration of the railcar, a braking notch that indicates the deceleration of the railcar, etc. The power conversion control unit 33 receives the state of the inverter contactor 19a from the first contactor control unit 31.

[0050] The control unit 15a having the above configuration acquires information from the control unit 15b. Specifically, the first contactor control unit 31 and the power conversion control unit 33 included in the control unit 15a acquire the determination result of the start determination unit 34 included in the control unit 15b, and the first contactor control unit 31 included in the control unit 15a acquires the determination result of the charge determination unit 35 included in the control unit 15b. The determination result of the start determination unit 34 included in the control unit 15b indicates whether the intermediate link voltage V2, which is a DC voltage applied to the electric circuit between the converter 11b and the first inverter 12b, is sufficient to start the internal combustion engine 91b. The determination result of the charge determination unit 35 indicates whether the power storage device 13b is being charged.

[0051] The start-up determination unit 34 determines whether the converter 11a is supplied with DC power for starting the internal combustion engine 91a. Specifically, the start-up determination unit 34 repeatedly acquires the value of the intermediate link voltage V1 from the voltage sensor and determines whether the measured value of the intermediate link voltage V1 is equal to or greater than the starting voltage. If the measured value of the intermediate link voltage V1 is equal to or greater than the starting voltage, it can be determined that the converter 11a is supplied with DC power for starting the internal combustion engine 91a. The start-up determination unit 34 outputs the determination result to the first contactor control unit 31, the power conversion control unit 33, and the control unit 15b. If the measured value of the intermediate link voltage V1 is equal to or greater than the starting voltage, it can be determined that the intermediate link voltage V1 is sufficient to start the internal combustion engine 91a. The starting voltage is a voltage value sufficient to start the internal combustion engine 91a and may be determined in advance according to the specifications of the internal combustion engine 91a and the generator 92a.

[0052] The charge determination unit 35 determines whether the power storage device 13a is sufficiently charged. Specifically, the charge determination unit 35 repeatedly acquires a measured value of the terminal voltage of the secondary battery of the power storage device 13a from a monitoring device included in the power storage device 13a and determines whether the measured terminal voltage of the secondary battery is equal to or greater than a charge threshold. The charge determination unit 35 outputs the determination result to the first contactor control unit 31, the second contactor control unit 32, and the control unit 15b. If the measured terminal voltage of the secondary battery is equal to or greater than the charge threshold, the power storage device 13a can be considered to be sufficiently charged. The charge threshold may be determined according to the specifications of the power storage device 13a.

[0053] As examples of charge thresholds, the charge determination unit 35 uses a first charge threshold, which is the voltage value of the storage device 13a when an amount of electricity stored is more than twice the starting amount of electricity of the internal combustion engine 91a, and a second charge threshold, which is lower than the first charge threshold and is the voltage value of the storage device 13a when an amount of electricity stored is the starting amount of the internal combustion engine 91a.

[0054] The hardware configurations of the control units 15a and 15b having the above-described configuration are similar, so the hardware configuration of the control unit 15a will be described below. As shown in FIG. 4 , the control unit 15a includes a processor 81, a memory 82, and an interface 83. The processor 81, the memory 82, and the interface 83 are connected to one another via a bus 80. The processor 81 includes any electronic circuit, including transistors, and is considered a circuit or a processor circuit. The functions of each unit in the control unit 15a 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 unit described above. In other words, the memory 82 stores programs for executing the processing of each unit in the control unit 15a.

[0055] The 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 disk, flexible disk, optical disk, compact disk, mini disk, DVD (Digital Versatile Disc), etc.

[0056] The control unit 15a is connected to the control unit 15b, the converter 11a, the first inverter 12a, the second inverter 14a, the power storage device contactor 18a, and the inverter contactor 19a via an interface 83. The interface 83 has an interface module that complies with one or more standards depending on the connection destination.

[0057] For example, when a railway vehicle parked in a depot begins operation, the drive control device 1 having the above configuration starts the internal combustion engines 91 a, 91 b. Specifically, the drive control device 1 converts DC power stored in the power storage devices 13 a, 13 b into AC power using the converters 11 a, 11 b, supplies the converted AC power to the generators 92 a, 92 b, and operates the generators 92 a, 92 b as electric motors to rotate them. This causes the shafts of the generators 92 a, 92 b to rotate the internal combustion engines 91 a, 91 b, whose output shafts are fixed, to rotate and start the internal combustion engines 91 a, 91 b.

[0058] When one of the power storage devices 13a, 13b is discharging, AC power cannot be supplied to one of the generators 92a, 92b, and therefore one of the internal combustion engines 91a, 91b cannot be started. In this case, the drive control device 1 uses the power stored in one of the power storage devices 13a, 13b to supply AC power to both of the generators 92a, 92b, thereby starting both of the internal combustion engines 91a, 91b. This provides the drive control device 1 that can start the internal combustion engines 91a, 91b when the supply of DC power to some of the converters 11a, 11b is stopped.

[0059] An example of the start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 having the above configuration will be described with reference to FIGS. 5 and 6. FIG. 5 shows an example of the operation of the drive control device 1 when both the power storage devices 13a, 13b are fully charged. As shown in graph A, time T1 is the time when the start command signal S1 changes from low to high. Before time T1, the power storage device contactors 18a, 18b and the inverter contactors 19a, 19b are open, and the converters 11a, 11b, the first inverters 12a, 12b, and the second inverters 14a, 14b are stopped. Therefore, before time T1, the internal combustion engines 91a, 91b, the generators 92a, 92b, the traction motors 93a, 93b, and the load devices 94a, 94b are all stopped.

[0060] At time T1, when the start command signal S1 changes from L level to H level, the second contactor control units 32 of the control units 15a and 15b respectively close the power storage device contactors 18a and 18b, as shown in graphs B and F. When the power storage device contactor 18a is closed, DC power is supplied from the power storage device 13a to the converter 11a, and as shown in graph C, the voltage of the power storage device 13a begins to decrease from a voltage value Va1 at time T1. The voltage value Va1 is the voltage value of the power storage device 13a when the power storage device 13a is charged with enough power to start the internal combustion engine 91a. When the power storage device contactor 18b is closed, DC power is supplied from the power storage device 13b to the converter 11b, and as shown in graph G, the voltage of the power storage device 13b begins to decrease from a voltage value Vb1 at time T1. The voltage value Vb1 is the voltage value of the power storage device 13b when the power storage device 13b is charged with enough power to start the internal combustion engine 91b.

[0061] Each of the power storage devices 13a and 13b preferably has a storage capacity equal to or greater than the total amount of power required to start up at least two internal combustion engines 91a and 91b. If the internal combustion engines 91a and 91b have the same specifications, the starting power required to start up the internal combustion engines 91a and 91b can be considered to be the same. For example, the voltage values ​​Va1 and Vb1 are the voltage values ​​of the power storage devices 13a and 13b when they store at least twice the amount of power required to start up the internal combustion engines 91a and 91b. The voltage values ​​Va1 and Vb1 are assumed to match the first charge threshold. After time T1, the DC power discharged from the power storage devices 13a and 13b charges the capacitors of the converters 11a and 11b, increasing the intermediate link voltages V1 and V2. In other words, the converters 11a and 11b receive DC power for starting up the internal combustion engines 91a and 91b, respectively.

[0062] The capacitors of the converters 11a and 11b are charged with DC power supplied from the power storage devices 13a and 13b to the converters 11a and 11b, and the timing at which the intermediate link voltages V1 and V2 reach the starting voltage is defined as time T2.

[0063] When the amount of power stored in each of the power storage devices 13a and 13b is equal to or greater than the startup power amount, the converters 11a and 11b convert the DC power supplied from the power storage devices 13a and 13b into AC power and supply the converted AC power to the generators 92a and 92b. Specifically, at time T2, the start-up determination units 34 of the control units 15a and 15b determine that the measured values ​​of the intermediate link voltages V1 and V2 are equal to or greater than the startup voltage and send the determination result to the first contactor control unit 31 and the power conversion control unit 33 of the control unit 15a and the first contactor control unit 31 and the power conversion control unit 33 of the control unit 15b. When the determination result of the start-up determination unit 34 indicates that the measured values ​​of the intermediate link voltages V1 and V2 are equal to or greater than the startup voltage, the power conversion control units 33 of the control units 15a and 15b control the multiple switching elements of the converters 11a and 11b. Under the control of the control units 15a and 15b, the converters 11a and 11b convert the DC power supplied from the power storage devices 13a and 13b into AC power, and supply the converted AC power to the generators 92a and 92b.

[0064] When the generators 92a, 92b receive AC power from the converters 11a, 11b, they operate as electric motors and rotate. Because the shafts of the generators 92a, 92b are fixed to the output shafts of the internal combustion engines 91a, 91b, respectively, the rotation of the generators 92a, 92b causes the internal combustion engines 91a, 91b to rotate, and the rotation speeds of the internal combustion engines 91a, 91b increase as shown in graphs D, H. The rotation speeds of the internal combustion engines 91a, 91b subsequently reach starting rotation speeds R1, R2, and the internal combustion engines 91a, 91b start, at time T3. The starting rotation speeds R1, R2 are rotation speeds at which the internal combustion engines 91a, 91b are considered to have started, and are determined according to the specifications of the internal combustion engines 91a, 91b. If the internal combustion engines 91a, 91b have the same specifications, the starting rotation speeds R1, R2 can be considered to be the same value.

[0065] After the internal combustion engines 91a, 91b start at time T3, the rotation speeds of the internal combustion engines 91a, 91b increase until they reach a rotation speed at which the generators 92a, 92b can generate electricity. The generators 92a, 92b, driven by the internal combustion engines 91a, 91b, start generating electricity. The generators 92a, 92b supply the generated AC power to the converters 11a, 11b.

[0066] When AC power is supplied from the generators 92a, 92b to the converters 11a, 11b, the power conversion control unit 33 possessed by the control units 15a, 15b controls the multiple switching elements of the converters 11a, 11b, causing the converters 11a, 11b to convert the AC power into DC power.

[0067] Specifically, when the rotation speed of the internal combustion engine 91 a obtained from the speed sensor reaches a rotation speed at which the generator 92 a can generate electricity, the power conversion control unit 33 included in the control unit 15 a controls the multiple switching elements included in the converter 11 a. The converter 11 a converts AC power supplied from the generator 92 a, which is driven by the internal combustion engine 91 a to generate electricity, into DC power, and supplies the converted DC power to the first inverter 12 a, the power storage device 13 a, and the second inverter 14 a.

[0068] The power conversion control unit 33 of the control unit 15b controls the multiple switching elements of the converter 11b when the rotation speed of the internal combustion engine 91b obtained from the speed sensor reaches a rotation speed at which the generator 92b can generate electricity. The converter 11b converts AC power supplied from the generator 92b, which is driven by the internal combustion engine 91b to generate electricity, into DC power, and supplies the converted DC power to the first inverter 12b, the power storage device 13b, and the second inverter 14b.

[0069] After time T3, the power conversion control units 33 of the control units 15a and 15b control the multiple switching elements of the converters 11a and 11b as described above, thereby supplying DC power from the converters 11a and 11b to the power storage devices 13a and 13b. As a result, the power storage devices 13a and 13b that were discharged when the internal combustion engines 91a and 91b were started are charged, and the voltage of the power storage device 13a starts to rise from the voltage values ​​Va2 and Vb2, as shown in graphs C and G.

[0070] The voltage value Va2 is lower than the voltage value Va1 and is the voltage value of the power storage device 13a when the power storage device 13a is charged with enough power to start the internal combustion engine 91a. For example, the voltage value Va2 is the voltage value of the power storage device 13a when an amount of power stored in the power storage device 13a is greater than the amount of power required to start the internal combustion engine 91a but less than twice the amount of power required to start the internal combustion engine 91a. The voltage value Va2 is assumed to coincide with the second charge threshold value.

[0071] Similarly, the voltage value Vb2 is a value lower than the voltage value Vb1 and is the voltage value of the power storage device 13b when the power storage device 13b is charged with enough power to start the internal combustion engine 91b. For example, the voltage value Vb2 is the voltage value of the power storage device 13b when an amount of power stored in the power storage device 13b is greater than the amount of power required to start the internal combustion engine 91b but less than twice the amount of power required to start the internal combustion engine 91b. The voltage value Vb2 is assumed to coincide with the second charge threshold value.

[0072] Thereafter, the voltages of the power storage devices 13a, 13b reach the voltage values ​​Va1, Vb1, and the charging of the power storage devices 13a, 13b is completed at time T4. In other words, at time T4, the power storage devices 13a, 13b are charged with enough power to start the next internal combustion engines 91a, 91b.

[0073] At time T4, charge determination units 35 included in control units 15 a and 15 b determine that the measured values ​​of the inter-terminal voltages of the secondary batteries included in power storage devices 13 a and 13 b are equal to or greater than the first charge threshold. Charge determination units 35 included in control units 15 a and 15 b send the determination results to first contactor control unit 31 included in control unit 15 a, second contactor control unit 32 included in control unit 15 a, and first contactor control unit 31 included in control unit 15 b, and second contactor control unit 32 included in control unit 15 b.

[0074] At time T4, when the determination result of the charge determination unit 35 of the control units 15a and 15b indicates that the measured value of the terminal voltage of the secondary battery of the storage device 13a or 13b is equal to or greater than the first charge threshold, the second contactor control unit 32 of the control units 15a and 15b opens the storage device contactors 18a and 18b as shown in graphs B and F.

[0075] After time T3 when the internal combustion engines 91a and 91b start, the power conversion control units 33 of the control units 15a and 15b acquire the values ​​of the intermediate link voltages V1 and V2 from voltage sensors (not shown) and control the multiple switching elements of the converters 11a and 11b to adjust the values ​​of the intermediate link voltages V1 and V2 to values ​​suitable for supplying to the first inverter 12a and the second inverter 14a. As a result, the values ​​of the intermediate link voltages V1 and V2 increase to values ​​suitable for supplying to the first inverters 12a and 12b and the second inverters 14a and 14b. In other words, the capacitor C1 of the first inverters 12a and 12b and the capacitors of the second inverters 14a and 14b are sufficiently charged.

[0076] After time T3, when the measured values ​​of the intermediate link voltages V1 and V2 acquired from the voltage sensors rise to values ​​suitable for operating the first inverters 12a and 12b, the power conversion control units 33 included in the control units 15a and 15b respectively control the multiple switching elements SW1-SW6 of the first inverters 12a and 12b. Under the control of the control unit 15a, the first inverter 12a converts DC power supplied from the converter 11a connected to the primary terminals 21a and 22a into AC power and supplies the converted AC power to the load device 94a connected to the secondary terminals 23a, 24a, and 25a. This enables operation of the load device 94a. Under the control of the control unit 15b, the first inverter 12b converts DC power supplied from the converter 11b connected to the primary terminals 21b and 22b into AC power and supplies the converted AC power to the load device 94b connected to the secondary terminals 23b, 24b, and 25b. This allows the load device 94b to operate.

[0077] After time T3, when the measured values ​​of the intermediate link voltages V1 and V2 acquired from the voltage sensors rise to values ​​suitable for operation of the second inverters 14a and 14b and the operation command signal S2 indicates a powering command, the power conversion control units 33 of the control units 15a and 15b each control the multiple switching elements of the second inverters 14a and 14b in accordance with the powering command. Under the control of the control unit 15a, the second inverter 14a converts the DC power supplied from the converter 11a into AC power and supplies the converted AC power to the traction motor 93a. The traction motor 93a receives the AC power and rotates, generating propulsion force for the railway vehicle. Under the control of the control unit 15b, the second inverter 14b converts the DC power supplied from the converter 11b into AC power and supplies the converted AC power to the traction motor 93b. The traction motor 93b receives the AC power and rotates, generating propulsion force for the railway vehicle.

[0078] As described above, at time T2, the start determination unit 34 of each of the control units 15a and 15b determines that the intermediate link voltages V1 and V2 are equal to or greater than the start voltage. In other words, the determination results obtained by the first contactor control unit 31 of the control unit 15a indicate that the intermediate link voltage V1 is sufficient to start the internal combustion engine 91a and that the intermediate link voltage V2 is sufficient to start the internal combustion engine 91b. The same is true for the determination results obtained by the first contactor control unit 31 of the control unit 15b. Therefore, the first contactor control units 31 of the control units 15a and 15b keep the inverter contactors 19a and 19b open, as shown in graphs E and I.

[0079] An example of the operation of the drive control device 1 when the power storage device 13a is fully charged and the power storage device 13b is discharged is shown in Fig. 6. Fig. 6 can be interpreted in the same way as Fig. 5. An example of the start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 when the power storage device 13a is fully charged and the power storage device 13b is discharged will be described below, focusing on the differences from the operation of the drive control device 1 shown in Fig. 5.

[0080] In the main converter 1b, because the power storage device 13b is in a discharged state, the terminal voltage of the secondary battery of the power storage device 13b is sufficiently small at time T1. For example, as shown in graph G, the terminal voltage of the secondary battery of the power storage device 13b is a voltage value Vb3. The voltage value Vb3 is a value that allows the power storage device 13b to be recharged without over-discharging. Even if the power storage device contactor 18b is closed at time T1, because the power storage device 13b is in a discharged state, sufficient DC power is not supplied from the power storage device 13b to the converter 11b to start the internal combustion engine 91b. In other words, the supply of DC power to the converter 11b for starting the internal combustion engine 91b is stopped.

[0081] Therefore, even at time T11, which is a certain time after time T1, the intermediate link voltage V2 in the main converter 1b does not reach the starting voltage. At time T11, the start determination unit 34 in the control unit 15b determines that the intermediate link voltage V2 is less than the starting voltage, and sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 in the control units 15a and 15b, respectively.

[0082] The first contactor control unit 31 included in the control unit 15a, 15b electrically connects the first inverter 12a, 12b when either of the converters 11a, 11b is not supplied with DC power for starting the internal combustion engine 91a, 91b. Specifically, the first contactor control unit 31 included in the control unit 15a, 15b closes the inverter contactors 19a, 19b when the start command signal S1 is at an H level and the determination result obtained from the start determination unit 34 included in the control unit 15a, 15b indicates that at least one of the intermediate link voltages V1, V2 is less than the starting voltage. In the example of FIG. 6 , when the first contactor control unit 31 included in the control unit 15a, 15b obtains the determination result indicating that the intermediate link voltage V2 is less than the starting voltage, it closes the inverter contactors 19a, 19b at time T11, as shown in graphs E and I.

[0083] When the power conversion control unit 33 of the control unit 15b obtains a determination result indicating that the intermediate link voltage V2 is lower than the starting voltage, the power conversion control unit 33 keeps the converter 11b, the first inverter 12b, and the second inverter 14b stopped. Therefore, as shown in graph H, at time T11, the rotation speed of the internal combustion engine 91b does not increase, and the internal combustion engine 91b is not started.

[0084] Because the power storage device contactor 18a is closed at time T1, DC power is supplied from the power storage device 13a to the first inverter 12a at time T11. At time T11, the first contactor control unit 31 of the control unit 15a closes the inverter contactor 19a and notifies the power conversion control unit 33 that the inverter contactor 19a has been closed. Upon receiving this notification, the power conversion control unit 33 of the control unit 15a controls the multiple switching elements SW1-SW6 of the first inverter 12a. Under the control of the control unit 15a, the first inverter 12a converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the first inverter 12b via the inverter contactors 19a and 19b. As a result, as shown in graph C, the voltage of the power storage device 13a decreases after time T11.

[0085] When the inverter contactors 19a and 19b are closed at time T11, the secondary terminals 23b, 24b, and 25b of the first inverter 12b connected to the converter 11b not receiving DC power are electrically connected to the secondary terminals 23a, 24a, and 25a of the first inverter 12a connected to the converter 11a receiving DC power. As a result, as shown by the solid arrows in Figure 7, the AC power output by the first inverter 12a is supplied to the first inverter 12b via the inverter contactors 19a and 19b.

[0086] When AC power is supplied from the first inverter 12a via the secondary terminals 23a, 24a, and 25a while the switching elements SW1-SW6 are in the off state, the first inverter 12b converts the AC power into DC power by rectifying it, and outputs the converted DC power from the primary terminals 21a and 22a. As described above, the converter 11b is stopped and the power storage device contactor 18b is closed, so the power storage device 13b is charged with the DC power output by the first inverter 12b, as shown by the dotted arrow in Figure 7.

[0087] As a result, the voltage of the power storage device 13b begins to rise, as shown in graph G in Fig. 6. Thereafter, the timing at which the voltage of the power storage device 13b reaches the voltage value Vb2 is defined as time T12. In other words, at time T12, the power storage device 13b is charged with enough power to start the internal combustion engine 91b.

[0088] At time T12, the charge determination unit 35 of the control unit 15b determines that the measured value of the terminal voltage of the secondary battery of the storage device 13b is greater than or equal to the second charge threshold, and sends the determination result to the first contactor control unit 31 of the control units 15a and 15b and the second contactor control unit 32 of the control unit 15b.

[0089] As described above, by supplying power to the first inverter 12a, the voltage of the power storage device 13a drops as shown in graph C, but at time T12, the power required to start the internal combustion engine 91a is stored.

[0090] After closing the inverter contactors 19a and 19b, the first contactor control units 31 of the control units 15a and 15b open the inverter contactors 19a and 19b when the determination result of the charge determination unit 35 of the control unit 15b indicates that the power storage device 13b is sufficiently charged. In detail, as shown in graphs E and I, at time T12, when the first contactor control units 31 of the control units 15a and 15b obtain a determination result indicating that the measured value of the inter-terminal voltage of the secondary battery of the power storage device 13b is equal to or higher than the second charge threshold, the first contactor control units 31 open the inverter contactors 19a and 19b.

[0091] Between time T11 and time T12, the capacitor of converter 11b is charged with DC power supplied from first inverter 12b, and therefore, at time T12, intermediate link voltage V2 reaches the starting voltage.

[0092] When the amount of power stored in each of the power storage devices 13a, 13b becomes equal to or greater than the startup power amount at time T12, the converters 11a, 11b convert the DC power supplied from the power storage devices 13a, 13b into AC power and supply the converted AC power to the generators 92a, 92b. Specifically, at time T12, the start determination unit 34 included in the control unit 15b determines that the measured value of the intermediate link voltage V2 is equal to or greater than the startup voltage, and sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 included in each of the control units 15a, 15b.

[0093] When the inverter contactors 19a and 19b are opened at time T12, the power conversion control unit 33 included in the control unit 15a stops the first inverter 12a. After that, when the start determination unit 34 obtains a determination result indicating that the measured values ​​of the intermediate link voltages V1 and V2 are equal to or greater than the start voltage, the power conversion control units 33 included in each of the control units 15a and 15b start controlling the converters 11a and 11b. Under the control of the power conversion control unit 33, the converters 11a and 11b convert the DC power supplied from the power storage devices 13a and 13b into AC power and supply the converted AC power to the generators 92a and 92b. In other words, after the first inverter 12a stops supplying AC power to the first inverter 12b, the converters 11a and 11b convert the DC power supplied from the power storage devices 13a and 13b into AC power and supply the converted AC power to the generators 92a and 92b.

[0094] Thereafter, the rotation speeds of the internal combustion engines 91a and 91b increase, similarly to the example of Fig. 5. The timing at which the rotation speeds of the internal combustion engines 91a and 91b reach the starting rotation speeds R1 and R2, respectively, is defined as time T13.

[0095] After the internal combustion engines 91 a, 91 b start at time T13, the rotation speeds of the internal combustion engines 91 a, 91 b increase and reach a rotation speed at which the generators 92 a, 92 b can generate electricity. The generators 92 a, 92 b driven by the internal combustion engines 91 a, 91 b then start generating electricity. The generators 92 a, 92 b supply the generated AC power to the converters 11 a, 11 b.

[0096] Because the power storage devices 13a and 13b discharge between time T12 and time T13, the voltages of the power storage devices 13a and 13b decrease to voltage values ​​Va3 and Vb3 at time T13. The voltage values ​​Va3 and Vb3 are voltage values ​​at which the power storage devices 13a and 13b can be recharged without being over-discharged.

[0097] As in the example of FIG. 5 , the converters 11a, 11b receive AC power from the generators 92a, 92b, convert the AC power into DC power, and supply the converted DC power to the power storage devices 13a, 13b. As a result, the discharged power storage devices 13a, 13b are charged, and as shown in graphs C, H, the voltages of the power storage devices 13a, 13b begin to rise from voltage values ​​Va3, Vb3. Thereafter, the voltages of the power storage devices 13a, 13b reach voltage values ​​Va1, Vb1, and the charging of the power storage devices 13a, 13b is completed at time T14. In other words, at time T14, the power storage devices 13a, 13b are charged with enough power to start the next internal combustion engines 91a, 91b.

[0098] As described above, according to the drive control device 1 of embodiment 1, it is possible to start both internal combustion engines 91a and 91b even when one of the converters 11a and 11b is not receiving a supply of DC power because one of the storage devices 13a and 13b is discharging.

[0099] (Embodiment 2) The method for starting the internal combustion engines 91a, 91b is not limited to the above-described example. A drive control device 1 that starts the internal combustion engines 91a, 91b using a method different from that of Embodiment 1 will be described in Embodiment 2. The configuration of the drive control device 1 according to Embodiment 2 is the same as that of Embodiment 1.

[0100] The start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 when both power storage devices 13a, 13b are fully charged is similar to the start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 according to the first embodiment shown in Fig. 5. Fig. 8 shows an example of the operation of the drive control device 1 when the power storage device 13a is fully charged and the power storage device 13b is discharged. Fig. 8 can be interpreted in the same way as Fig. 6. The operation of the drive control device 1 from time T1 to time T11 is similar to the operation of the drive control device 1 according to the first embodiment shown in Fig. 6.

[0101] At time T11, the start-up determination unit 34 included in the control unit 15a determines that the measured value of the intermediate link voltage V1 is equal to or greater than the start-up voltage and sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 included in each of the control units 15a and 15b. When the determination result of the start-up determination unit 34 indicates that the measured value of the intermediate link voltage V1 is equal to or greater than the start-up voltage, the power conversion control unit 33 included in the control unit 15a controls the multiple switching elements of the converter 11a. Under the control of the control unit 15a, the converter 11a converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the generator 92a.

[0102] When the generator 92a receives AC power from the converter 11a, it operates as an electric motor and rotates. Because the shaft of the generator 92a is fixed to the output shaft of the internal combustion engine 91a, the internal combustion engine 91a rotates as the generator 92a rotates, and the rotation speed of the internal combustion engine 91a increases as shown in graph D. Thereafter, the rotation speed of the internal combustion engine 91a reaches the starting rotation speed R1, and the timing at which the internal combustion engine 91a starts is defined as time T21.

[0103] At time T11, after the inverter contactors 19a and 19b are turned on, the power conversion control unit 33 included in the control unit 15a controls the multiple switching elements SW1-SW6 of the first inverter 12a. Under the control of the control unit 15a, the first inverter 12a converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the first inverter 12b via the inverter contactors 19a and 19b.

[0104] After time T21, the power storage device 13a supplies power to the operating converter 11a and first inverter 12a, as shown by the solid arrows in Fig. 9. In other words, the converter 11a, which is supplied with DC power, converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the generator 92a while the first inverter 12a connected to the converter 11a supplies AC power to the first inverter 12b connected to the converter 11b that is not supplied with DC power. In this way, the main conversion device 1a starts the internal combustion engine 91a and supplies power to the main conversion device 1b in parallel, so the voltage of the power storage device 13a drops, as shown by graph C in Fig. 8.

[0105] After the internal combustion engine 91a starts at time T21, the rotation speed of the internal combustion engine 91a increases until it reaches a rotation speed at which the generator 92a can generate electricity, which is time T22. At time T22, the generator 92a driven by the internal combustion engine 91a starts generating electricity and supplies the generated AC power to the converter 11a.

[0106] When AC power is supplied from the generator 92a to the converter 11a, the power conversion control unit 33 included in the control unit 15a controls multiple switching elements of the converter 11a. Under the control of the control unit 15a, the converter 11a converts the AC power supplied from the generator 92a, which is driven by the internal combustion engine 91a to generate electricity, into DC power and supplies the converted DC power to the power storage device 13a and the first inverter 12a. As a result, the discharged power storage device 13a is charged, and the voltage value of the power storage device 13a begins to rise, as shown in graph C. Furthermore, the first inverter 12a converts the DC power supplied from the converter 11a into AC power and supplies the converted AC power to the first inverter 12b.

[0107] The power storage device 13a is charged with DC power supplied from the converter 11a, and the voltage of the power storage device 13a begins to rise, as shown in graph C. Thereafter, the measured inter-terminal voltage of the secondary battery of the power storage device 13a reaches a voltage value Va1, and charging of the power storage device 13a is completed at time T25. In other words, at time T25, the power storage device 13a has been charged with enough power to start the next internal combustion engines 91a, 91b.

[0108] At time T25, the charge determination unit 35 of the control unit 15a determines that the measured value of the terminal voltage of the secondary battery of the storage device 13a is greater than or equal to the first charge threshold, and sends the determination result to the first contactor control unit 31 of the control units 15a and 15b and the second contactor control unit 32 of the control unit 15a.

[0109] When the second contactor control unit 32 of the control unit 15a obtains, at time T25, a determination result from the charge determination unit 35 of the control unit 15a indicating that the measured value of the terminal voltage of the secondary battery of the storage device 13a is equal to or greater than the first charge threshold, the second contactor control unit 32 opens the storage device contactor 18a as shown in graph B.

[0110] As described above, the first inverter 12b receives AC power from the first inverter 12a, and converts the supplied AC power into DC power by rectifying it while the switching elements SW1-SW6 are in the off state, and outputs the converted DC power. As described above, the converter 11b is stopped and the power storage device contactor 18b is turned on, so the power storage device 13b is charged with the DC power output by the first inverter 12b, as shown by the dotted arrow in Figure 9.

[0111] As a result, the voltage of the power storage device 13b begins to rise, as shown in graph G in Fig. 8. Thereafter, the timing at which the voltage of the power storage device 13b reaches the voltage value Vb1 is defined as time T23. In other words, at time T23, the power storage device 13b is charged with enough power to start the internal combustion engine 91b.

[0112] At time T23, the charge determination unit 35 of the control unit 15b determines that the measured value of the terminal voltage of the secondary battery of the storage device 13b is greater than or equal to the first charge threshold, and sends the determination result to the first contactor control unit 31 of the control units 15a and 15b and the second contactor control unit 32 of the control unit 15b.

[0113] After closing the inverter contactors 19a and 19b, the first contactor control units 31 of the control units 15a and 15b open the inverter contactors 19a and 19b when the determination result of the charge determination unit 35 of the control unit 15b indicates that the power storage device 13b is sufficiently charged. More specifically, when the first contactor control units 31 of the control units 15a and 15b obtain a determination result indicating that the measured value of the terminal voltage of the secondary battery of the power storage device 13b is equal to or greater than the first charge threshold, they open the inverter contactors 19a and 19b at time T23, as shown in graphs E and I.

[0114] By time T23, the capacitor of the converter 11b is charged with the DC power supplied from the first inverter 12b, and therefore, at time T23, the intermediate link voltage V2 reaches the starting voltage.

[0115] At time T23, the start-up determination unit 34 of the control unit 15b determines that the measured value of the intermediate link voltage V2 is greater than or equal to the start-up voltage, and sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 of each of the control units 15a and 15b.

[0116] When the inverter contactors 19a, 19b are opened at time T23, the power conversion control unit 33 included in the control unit 15b starts controlling the converter 11b. Under the control of the control unit 15b, the converter 11b converts the DC power supplied from the power storage device 13b into AC power and supplies the converted AC power to the generator 92b. The rotation of the generator 92b, which operates as an electric motor receiving the supply of AC power, rotates the internal combustion engine 91b, and the rotation speed of the internal combustion engine 91b increases, as shown in graph H. The timing at which the rotation speed of the internal combustion engine 91b reaches the starting rotation speed R2 is defined as time T24.

[0117] After the internal combustion engine 91b starts at time T24, the rotation speed of the internal combustion engine 91b increases and reaches a rotation speed at which the generator 92b can generate electricity. The generator 92b, driven by the internal combustion engine 91b, starts generating electricity. The generator 92b supplies the generated AC power to the converter 11b.

[0118] Converter 11b, which receives AC power from generator 92b, converts the AC power into DC power and supplies the converted DC power to the power storage device 13b. As a result, the discharged power storage device 13b is charged, and as shown in graph G, the voltage of power storage device 13b begins to rise at time T25. Thereafter, the voltage of power storage device 13b reaches voltage value Vb1, and charging of power storage device 13b is completed at time T26. In other words, at time T26, the power storage device 13b is charged with enough power to start the next internal combustion engine 91b.

[0119] At time T26, the charge determination unit 35 of the control unit 15b determines that the measured value of the terminal voltage of the secondary battery of the storage device 13b is greater than or equal to the first charge threshold, and sends the determination result to the first contactor control unit 31 of the control units 15a and 15b and the second contactor control unit 32 of the control unit 15b.

[0120] When the second contactor control unit 32 of the control unit 15b obtains, at time T26, a determination result from the charge determination unit 35 of the control unit 15b indicating that the measured value of the terminal voltage of the secondary battery of the storage device 13b is equal to or greater than the first charge threshold, the second contactor control unit 32 opens the storage device contactor 18b as shown in graph F.

[0121] As described above, according to the drive control device 1 of embodiment 2, even when one of the power storage devices 13a, 13b is discharging and therefore one of the converters 11a, 11b is not receiving a supply of DC power, it is possible to start both of the internal combustion engines 91a, 91b.

[0122] Furthermore, the converter 11a receiving the supply of DC power converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the generator 92a while the first inverter 12a connected to the converter 11a supplies AC power to the first inverter 12b connected to the converter 11b that is not receiving the supply of DC power. As described above, the drive control device 1 starts the internal combustion engine 91a first while charging the discharged power storage device 13b, so that the internal combustion engine 91a that can be started can be started quickly.

[0123] (Embodiment 3) The method of starting the internal combustion engines 91a, 91b is not limited to the above-described examples. A drive control device 1 that starts the internal combustion engines 91a, 91b using a method different from those used in embodiments 1 and 2 will be described in embodiment 3. The configuration of the drive control device 1 according to embodiment 3 is the same as that of embodiment 1. However, the first contactor control unit 31 included in the control units 15a, 15b acquires the rotation speed of the internal combustion engines 91a, 91b from a speed sensor, and the second contactor control unit 32 included in the control units 15a, 15b acquires the determination result from the start determination unit 34.

[0124] The start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 when both power storage devices 13a, 13b are fully charged is similar to the start-up process of the internal combustion engines 91a, 91b performed by the drive control device 1 according to embodiment 1 shown in Fig. 5. An example of the operation of the drive control device 1 when the power storage device 13a is fully charged and the power storage device 13b is discharged is shown in Fig. 10. The interpretation of Fig. 10 is similar to that of Fig. 6. The operation of the main converter 1a provided in the drive control device 1 according to embodiment 3 is similar to the operation of the main converter 1a provided in the drive control device 1 according to embodiment 2 shown in Fig. 8.

[0125] In the main converter 1b, because the power storage device 13b is in a discharged state, the terminal voltage of the secondary battery of the power storage device 13b is sufficiently small at time T1. For example, as shown in graph G, the terminal voltage of the secondary battery of the power storage device 13b is a voltage value Vb3. Even if the power storage device contactor 18b is closed at time T1, because the power storage device 13b is in a discharged state, sufficient DC power is not supplied from the power storage device 13b to the converter 11b to start the internal combustion engine 91b.

[0126] Therefore, even at time T11, the intermediate link voltage V2 in the main converter 1b does not reach the starting voltage. At time T11, the start determination unit 34 of the control unit 15b determines that the intermediate link voltage V2 is less than the starting voltage, and sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 of the control units 15a and 15b, respectively, and to the second contactor control unit 32 of the control unit 15b.

[0127] When the first contactor control unit 31 of the control unit 15b obtains a determination result indicating that the intermediate link voltage V2 is less than the starting voltage, it closes the inverter contactor 19b at time T11, as shown in graph I.

[0128] When the second contactor control unit 32 of the control unit 15b obtains a determination result indicating that the intermediate link voltage V2 is less than the starting voltage, as shown in graph F, the second contactor control unit 32 opens the storage device contactor 18b.

[0129] When the power conversion control unit 33 of the control unit 15b obtains a determination result indicating that the intermediate link voltage V2 is lower than the starting voltage, the power conversion control unit 33 keeps the converter 11b, the first inverter 12b, and the second inverter 14b stopped. Therefore, as shown in graph H, at time T11 when the rotation speed of the internal combustion engine 91a starts to increase, the rotation speed of the internal combustion engine 91b does not increase, and the internal combustion engine 91b is not started.

[0130] After time T11, when AC power is supplied from the first inverter 12a via the secondary terminals 23a, 24a, and 25a with the switching elements SW1-SW6 in the off state, the first inverter 12b converts the AC power into DC power by rectifying it, and outputs the converted DC power from the primary terminals 21a and 22a.

[0131] Because the storage device contactor 18b is open, the capacitor of the converter 11b is charged with DC power supplied from the first inverter 12b, as indicated by the dotted arrow in Fig. 11. When the start determination unit 34 of the control unit 15b determines that the measured value of the intermediate link voltage V2 is equal to or higher than the start voltage, it sends the determination result to the first contactor control unit 31 and the power conversion control unit 33 of the control units 15a and 15b, respectively.

[0132] When the control unit 15b receives from the start determination unit 34 a determination result indicating that the measured value of the intermediate link voltage V2 is equal to or greater than the start-up voltage, the power conversion control unit 33 included in the control unit 15b starts controlling the converter 11b. Under the control of the power conversion control unit 33, the converter 11b converts the DC power supplied from the first inverter 12b into AC power and supplies the converted AC power to the generator 92b. The rotation of the generator 92b, which operates as an electric motor receiving the supply of AC power, rotates the internal combustion engine 91b, and the rotation speed of the internal combustion engine 91b increases as shown in graph H. At time T22, the rotation speed of the internal combustion engine 91b reaches the starting rotation speed R2.

[0133] After the internal combustion engine 91b starts at time T22, the rotation speed of the internal combustion engine 91b increases and reaches a rotation speed at which the generator 92b can generate electricity, which is time T31. At time T31, the generator 92b driven by the internal combustion engine 91b starts generating electricity. The generator 92b supplies the generated AC power to the converter 11b. At time T31, the rotation speeds of the internal combustion engines 91a, 91b are equal to or greater than the rotation speed at which the generators 92a, 92b can generate electricity, so the first contactor control units 31 included in the control units 15a, 15b open the inverter contactors 19a, 19b, as shown in graphs E and I.

[0134] The converter 11b converts the AC power supplied from the generator 92b into DC power and supplies the converted DC power to the first inverter 12b, the power storage device 13b, and the second inverter 14b. This charges the power storage device 13b, and as shown in graph G, the voltage of the power storage device 13b begins to rise at time T31. Thereafter, the voltage of the power storage device 13b reaches a voltage value Vb1, and charging of the power storage device 13b is completed at time T32. In other words, at time T32, the power storage device 13b is charged with enough power to start the internal combustion engine 91b next.

[0135] At time T32, the charge determination unit 35 of the control unit 15b determines that the measured value of the terminal voltage of the secondary battery of the storage device 13b is greater than or equal to the first charge threshold, and sends the determination result to the first contactor control unit 31 of the control units 15a and 15b and the second contactor control unit 32 of the control unit 15b.

[0136] When, at time T32, the determination result of the charge determination unit 35 of the control unit 15b indicates that the measured value of the terminal voltage of the secondary battery of the storage device 13b is equal to or greater than the first charge threshold, the second contactor control unit 32 of the control unit 15b opens the storage device contactor 18b as shown in graph F.

[0137] As described above, according to the drive control device 1 of embodiment 3, even when either of the power storage devices 13a, 13b is discharging and therefore either of the converters 11a, 11b is not receiving a supply of DC power, it is possible to start both of the internal combustion engines 91a, 91b.

[0138] Furthermore, the converter 11a receiving DC power converts the DC power supplied from the power storage device 13a into AC power and supplies the converted AC power to the generator 92a while the first inverter 12a connected to the converter 11a supplies AC power to the first inverter 12b connected to the converter 11b that is not receiving DC power. As a result, the drive control device 1 starts the internal combustion engine 91a first and supplies power to the converter 11b for starting the internal combustion engine 91b, making it possible to quickly start the startable internal combustion engine 91a. In the main conversion device 1b, the internal combustion engine 91b is started before charging the power storage device 13b, making it possible to quickly start the internal combustion engines 91a and 91b.

[0139] The present disclosure is not limited to the above example. The above circuit configuration is an example and can be changed as desired. As an example, the circuit configuration of the first inverters 12a, 12b is not limited to the example of FIG. 2 and can be any circuit that can convert DC power supplied from the converters 11a, 11b into AC power and convert AC power supplied from the other first inverters 12a, 12b into DC power.

[0140] 12 , in addition to the configuration of the drive control device 1 described above, further includes DC (Direct Current) / DC converters 41 a and 41 b that operate as step-down circuits that step down the DC power supplied from the converters 11 a and 11 b and supply the power to the power storage devices 13 a and 13 b, respectively. Specifically, the main conversion device 2 a included in the drive control device 2 includes a DC / DC converter 41 a that steps down the DC power supplied from the converter 11 a and supplies the stepped-down DC power to the power storage device 13 a. The main conversion device 2 b included in the drive control device 2 includes a DC / DC converter 41 b that steps down the DC power supplied from the converter 11 b and supplies the stepped-down DC power to the power storage device 13 b.

[0141] As in the first embodiment, even if the output voltage of the converters 11a, 11b rises to a value suitable for the first inverters 12a, 12b and the second inverters 14a, 14b immediately after the start of the internal combustion engines 91a, 91b, the DC / DC converters 41a, 41b step down the DC power and supply it to the power storage devices 13a, 13b, so there is no need to use large power storage devices that can withstand high voltages as the power storage devices 13a, 13b. This makes it possible to prevent the drive control device 2 from becoming larger.

[0142] In the drive control device 2, when one of the power storage devices 13a, 13b is discharging, one of the first inverters 12a, 12b converts the AC power supplied from the other of the first inverters 12a, 12b into DC power and supplies the converted DC power to the power storage device 13a or 13b via the DC / DC converter 41a or 41b. At this time, the DC / DC converters 41a, 41b operate as step-down circuits that step down the DC power supplied from the first inverters 12a, 12b and supply it to the power storage devices 13a, 13b.

[0143] The DC / DC converters 41a, 41b may operate as boost circuits that boost the DC power output from the power storage devices 13a, 13b and supply it to the first inverters 12a, 12b. In the drive control device 2, when one of the power storage devices 13a, 13b is discharging, one of the first inverters 12a, 12b converts the DC power supplied from the power storage device 13a or 13b via the DC / DC converter 41a or 41b into AC power and supplies the converted AC power to the other of the first inverters 12a, 12b. In this case, the DC / DC converters 41a, 41b operate as boost circuits that boost the DC power supplied from the power storage devices 13a, 13b and supply it to the first inverters 12a, 12b.

[0144] Since the DC / DC converters 41 a, 41 b operate as boost circuits, it is not necessary to use the power storage devices 13 a, 13 b as large-capacity power storage devices capable of operating the first inverters 12 a, 12 b, which makes it possible to prevent the drive control device 2 from becoming large in size.

[0145] The drive control device 2 may include a step-down circuit and a step-up circuit, which are independent circuits, instead of the DC / DC converters 41a and 41b.

[0146] As another example, a drive control device 3 having only one power storage device 13a is shown in Figure 13. In this drive control device 3, the main converter 3a is equipped with the power storage device 13a, but the main converter 3b is equipped with neither a power storage device nor a power storage device contactor. The first contactor control units 31 in the control units 15a and 15b obtain the rotation speeds of the internal combustion engines 91a and 91b from speed sensors. As shown in Figure 14, when the start command signal S1 goes high at time T1, the first contactor control units 31 in the control units 15a and 15b in the drive control device 3 close the inverter contactors 19a and 19b, as shown in graphs E and G.

[0147] Thereafter, the internal combustion engine 91a starts at time T21, and the internal combustion engine 91b starts at time T22, as in the third embodiment. When the rotation speed of the internal combustion engine 91b reaches a rotation speed at which the generator 92b can generate electricity at time T31, the first contactor control unit 31 included in the control units 15a and 15b opens the inverter contactors 19a and 19b.

[0148] The method for starting the internal combustion engines 91a, 91b is not limited to the above example. As an example, the drive control device 1 according to the third embodiment may not charge the power storage device 13b when the power storage device 13b is faulty. Specifically, as shown in FIG. 15 , the second contactor control unit 32 of the control unit 15b included in the drive control device 1 may keep the power storage device contactor 18b open, as shown in graph G, if the voltage value of the inter-terminal voltage of the power storage device 13b is less than the second charge threshold at time T1. In this case, it is also possible to start both internal combustion engines 91a, 91b using the power stored in the power storage device 13a.

[0149] 6, the internal combustion engines 91a and 91b are started at the same timing, but the internal combustion engines 91a and 91b may be started at different timings. As an example, the power conversion control unit 33 included in the control unit 15a may obtain the rotation speed of the internal combustion engine 91b from a speed sensor and start controlling the converter 11a after the internal combustion engine 91b starts to rotate. As a result, the rotation speed of the internal combustion engine 91a starts to increase after the rotation speed of the internal combustion engine 91b starts to increase.

[0150] 10, the inverter contactors 19a, 19b are opened at time T31 when the internal combustion engine 91b starts and the generator 92b is ready to generate power, but the inverter contactors 19a, 19b may be opened after time T31. As an example, the inverter contactors 19a, 19b may be opened at time T32 when charging of the power storage device 13b is completed.

[0151] As another example, when the start-up determination unit 34 determines that the intermediate link voltage V1 or the intermediate link voltage V2 is less than the start-up voltage after the charging period, which is the time required to charge the capacitors of the converters 11a and 11b, has elapsed since the start-up command signal S1 changed from L level to H level, the drive control device 1 may output the determination result of the start-up determination unit 34 to a display device provided in the driver's cab.

[0152] After outputting the above-mentioned determination result to a display device provided in the driver's cab, when the driver operates a charging switch to instruct charging of the discharging storage device 13a or 13b, the drive control device 1 may use the power of one of the charged storage devices 13a, 13b to charge the other of the discharging storage devices 13a, 13b as shown in embodiment 1.

[0153] When charging of the power storage device 13a or the power storage device 13b that was discharging at the time when the start command signal S1 changed from L level to H level is completed, the drive control device 1 may output a message to the effect that charging is completed to a display device provided in the driver's cab and prompt the driver to stop and restart the drive control device 1. Because the power storage device 13a or the power storage device 13b that was discharging is now charged, in other words, because both the power storage devices 13a, 13b are sufficiently charged, restarting the drive control device 1 will start both the internal combustion engines 91a, 91b.

[0154] As another example, immediately after the start of the internal combustion engines 91a, 91b, the output voltage of the converters 11a, 11b may be maintained at a value suitable for the power storage devices 13a, 13b, which is lower than the value suitable for the first inverters 12a, 12b and the second inverters 14a, 14b, and the power storage devices 13a, 13b may be charged. In this case, when the determination result of the charge determination unit 35 indicates that the charging of the power storage devices 13a, 13b is completed, the power conversion control unit 33 included in the control unit 15a, 15b increases the output voltage of the converters 11a, 11b to a value suitable for the first inverters 12a, 12b and the second inverters 14a, 14b, and operates the first inverters 12a, 12b and the second inverters 14a, 14b.

[0155] As another example, the start-up determination unit 34 of the control units 15a, 15b may determine whether the converters 11a, 11b are receiving a supply of DC power to start the internal combustion engines 91a, 91b from the voltage value of the terminal-to-terminal voltage of the storage devices 13a, 13b.

[0156] The operation of the internal combustion engines 91a, 91b after startup is not limited to the above example. When the first inverters 12a, 12b are operating synchronously, the first contactor control units 31 included in the control units 15a, 15b may close the inverter contactors 19a, 19b immediately after startup of the internal combustion engines 91a, 91b.

[0157] In the drive control device 1 shown in Embodiment 2, when only the internal combustion engine 91a is started, the power conversion control unit 33 of the control unit 15a may control the multiple switching elements of the second inverter 14a when it receives an operation command signal S2 indicating a powering command, regardless of the determination result received from the start determination unit 34 of the control unit 15b. This causes the second inverter 14a to convert DC power to AC power and supply the converted AC power to the traction motor 93a. The traction motor 93a, supplied with AC power, generates propulsion power for the railway vehicle. As a result, it is possible to run the railway vehicle even when only the internal combustion engine 91a is started.

[0158] The number of internal combustion engines and main converters mounted on one railway vehicle is not limited to the above example and may be any number equal to or greater than two. Fig. 16 shows a railway vehicle drive system 200 that drives a railway vehicle consisting of cars 100a, 100b, and 100c. In addition to the configuration of railway vehicle drive system 100, railway vehicle drive system 200 includes an internal combustion engine 91c as a power source, a generator 92c that generates AC power when driven by the internal combustion engine 91c, a traction motor 93c that receives a supply of AC power to rotate and generate propulsive force for the railway vehicle, and a load device 94c that operates on a supply of AC power.

[0159] The traction control device 4 included in the railway vehicle traction device 200 includes three main conversion devices 1a, 1b, and 1c. The configurations of the main conversion devices 1a and 1b are the same as those in the first embodiment. The configuration of the main conversion device 1c is the same as that of the main conversion devices 1a and 1b, but with the addition of an inverter contactor 20c. In detail, the main conversion device 1c includes a converter 11c that converts AC power supplied from a generator 92c into DC power and outputs the converted DC power, a first inverter 12c that converts the DC power supplied from the converter 11c into AC power and outputs the converted AC power, a second inverter 14c that converts the DC power supplied from the converter 11c into AC power and supplies the converted AC power to a main motor 93c, and a power storage device 13c connected to the converter 11c, the first inverter 12c, and the second inverter 14c. The main conversion device 1c includes a power storage device contactor 18c that switches electrical connections between the power storage device 13c and the converter 11c, the first inverter 12c, and the second inverter 14c, and inverter contactors 19c and 20c. The main conversion device 1c also includes a control unit 15c that controls the converter 11c, the first inverter 12c, the second inverter 14c, the power storage device contactor 18c, and the inverter contactor 19c.

[0160] The main converter 1c is mounted on a vehicle 100c. In order to avoid complicating the diagram, primary terminals, which are DC side terminals, and secondary terminals, which are AC side terminals, of the first inverters 12a, 12b, and 12c, as well as transformers and AC capacitors connected to the secondary terminals of the first inverters 12a, 12b, and 12c are not shown in Fig. 16 .

[0161] When the power storage device 13c is in a discharged state, for example, the first inverter 12a supplies AC power to the first inverter 12c via the inverter contactors 19a and 19c, as shown by the solid arrows in Fig. 17. The first inverter 12c converts the AC power supplied from the first inverter 12a into DC power and outputs the converted DC power. As shown by the dotted arrows in Fig. 17, when the power storage device 13c is charged with the DC power output by the first inverter 12c, it becomes possible to store sufficient power in the power storage device 13c to start the next internal combustion engine 91c.

[0162] When the power storage device 13b is in a discharged state, for example, the first inverter 12c supplies AC power to the first inverter 12b via the inverter contactors 20c and 19b, as shown by the solid arrow in Fig. 18. The first inverter 12b converts the AC power supplied from the first inverter 12c into DC power and outputs the converted DC power. As shown by the dotted arrow in Fig. 18, when the power storage device 13b is charged with the DC power output by the first inverter 12b, it becomes possible to store sufficient power in the power storage device 13b to start the next internal combustion engine 91b.

[0163] As in embodiment 3, the drive control device 1 may start the internal combustion engine 91a, internal combustion engine 91b, or internal combustion engine 91c that has not been started, and then charge the discharging storage device 13a, storage device 13b, or storage device 13c.

[0164] The hardware configuration of the control units 15a, 15b, and 15c is not limited to the above example. As an example, a modified example of the hardware configuration of the control unit 15a is shown in FIG. 19. As shown in FIG. 19, the control unit 15a may be realized by a processing circuit 84. The processing circuit 84 is connected to the control unit 15b, the converter 11a, the first inverter 12a, the second inverter 14a, the power storage device contactor 18a, and the inverter contactor 19a via an interface circuit 85.

[0165] When the processing circuitry 84 is dedicated hardware, the processing circuitry 84 includes, 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 thereof. Each unit of the control units 15 a, 15 b may be realized by an individual processing circuit 84 or may be realized by a common processing circuit 84.

[0166] Some of the functions of the control units 15a, 15b, and 15c may be implemented by dedicated hardware, and other functions may be implemented by software or firmware. For example, in the control unit 15a of the drive control device 1 according to the first embodiment, the first contactor control unit 31, the second contactor control unit 32, and the power conversion control unit 33 may be implemented by a processing circuit 84 shown in Fig. 19, and the start determination unit 34 and the charge determination unit 35 may be implemented by a processor 81 shown in Fig. 4 reading and executing a program stored in a memory 82.

[0167] At least a part of the control units 15a, 15b, and 15c may be realized as one function of a train information management system.

[0168] The drive control device 1-4 is not limited to being mounted on a railway vehicle, but may also be mounted on any mobile object powered by multiple internal combustion engines, such as a trolley bus.

[0169] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure.

[0170] 1, 2, 3, 4 Drive control device, 1a, 1b, 1c, 2a, 2b, 3a, 3b Main conversion device, 11a, 11b, 11c Converter, 12a, 12b, 12c First inverter, 13a, 13b, 13c Electric storage device, 14a, 14b, 14c Second inverter, 15a, 15b, 15c Control unit, 16a, 16b Transformer, 17a, 17b AC capacitor, 18a, 18b, 18c Electric storage device contactor, 19a, 19b, 19c, 20c Inverter contactor, 21a, 21b, 22a, 22b Primary terminal, 23a, 23b, 24a, 24b, 25a, 25b Secondary terminal, 31 First contactor control unit, 32 Second contactor control unit, 33 Power conversion control unit, 34 Start determination unit, 35 charge determination unit, 41a, 41b DC / DC converter, 80 bus, 81 processor, 82 memory, 83 interface, 84 processing circuit, 85 interface circuit, 91a, 91b, 91c internal combustion engine, 92a, 92b, 92c generator, 93a, 93b, 93c traction motor, 94a, 94b, 94c load device, 100, 200 railway vehicle drive device, 100a, 100b, 100c vehicle, C1 capacitor, D1, D2, D3, D4, D5, D6 return diode, S1 start command signal, S2 operation command signal, SW1, SW2, SW3, SW4, SW5, SW6 switching element.

Claims

1. A drive control device for controlling the drive of a railway vehicle powered by a plurality of internal combustion engines, comprising: a plurality of converters provided corresponding to the internal combustion engines, each provided for a generator that generates AC power when driven by the internal combustion engine, and that performs bidirectional conversion between AC power and DC power; a plurality of first inverters provided for each converter, each having a primary terminal connected to the converter and a secondary terminal connected to a load device that operates upon the supply of AC power, and performing bidirectional conversion between DC power and AC power; and at least one power storage device having a storage capacity greater than the starting power amount of the internal combustion engines, connected to the converter and the primary terminal of the first inverter corresponding to the converter, and charged with DC power output by the converter or the first inverter, wherein the secondary terminals of the plurality of first inverters are connected to each other, and a drive control device configured to: when starting the plurality of internal combustion engines, the converter receiving a supply of DC power for starting the internal combustion engines converts the DC power into AC power and supplies the converted AC power to the generator; and the first inverter connected to the converter not receiving a supply of DC power for starting the internal combustion engines receives a supply of AC power generated by the first inverter connected to the power storage device, the amount of stored power being greater than the starting power amount, by converting the DC power supplied from the power storage device, converts the supplied AC power into DC power, and outputs the converted DC power from the primary terminals.

2. A drive control device according to claim 1, comprising a plurality of the power storage devices provided for each of the converters, wherein, at the time of starting the plurality of internal combustion engines, the first inverter connected to the converter that is not supplied with DC power for starting the internal combustion engines receives AC power generated by the first inverter connected to the power storage device having an amount of stored power greater than the starting power amount by converting the DC power supplied from the power storage device, converts the supplied AC power into DC power, and supplies the converted DC power to the power storage device.

3. A drive control device according to claim 2, wherein, when the amount of electric power stored in each of the power storage devices is equal to or greater than the starting electric power amount at the start of the plurality of internal combustion engines, each of the converters converts DC power supplied from the power storage devices into AC power and supplies the converted AC power to the generator.

4. A drive control device according to claim 2 or 3, further comprising at least one step-down circuit provided for each of the power storage devices, connected to the primary terminal of the first inverter, and stepping down the DC power supplied from the connected first inverter and supplying it to the power storage device, wherein, when starting the plurality of internal combustion engines, the first inverter connected to the converter that is not supplied with DC power for starting the internal combustion engines receives AC power from the first inverter connected to the power storage device whose stored power amount is greater than the starting power amount, converts the supplied AC power into DC power, and supplies the converted DC power to the power storage device via the step-down circuit.

5. The drive control device according to claim 4, wherein the step-down circuit is further connected to the converter, and when the internal combustion engine starts, the converter converts AC power output by the generator driven by the started internal combustion engine into DC power, supplies the converted DC power to the first inverter, and supplies the converted DC power to the power storage device via the step-down circuit.

6. A drive control device according to claim 1, comprising one of the power storage devices, wherein when the plurality of internal combustion engines are started, the first inverter connected to the power storage device converts DC power supplied from the power storage device into AC power and outputs the converted AC power from the secondary terminal, and the first inverter connected to the power storage device receives the AC power output from the secondary terminal, converts the supplied AC power into DC power and supplies the converted DC power to the converter.

7. A drive control device according to any one of claims 1 to 6, wherein the storage device has a storage capacity equal to or greater than the total amount of starting power of at least two of the internal combustion engines, and when starting the multiple internal combustion engines, the first inverter connected to the converter that is not supplied with DC power for starting the internal combustion engines receives a supply of AC power generated by the first inverter connected to the storage device, the amount of stored power being equal to or greater than the total amount of starting power of at least two of the internal combustion engines, converts the supplied AC power into DC power, and outputs the converted DC power from the primary terminals.

8. A drive control device according to any one of claims 1 to 7, further comprising at least one boost circuit provided for each of the power storage devices, connected to the power storage devices and the primary terminals of the first inverter, and configured to boost the DC power output by the power storage devices and supply the boosted power to the first inverter.

9. A drive control device according to any one of claims 1 to 8, wherein, when starting the plurality of internal combustion engines, the converter receiving a supply of DC power from the storage device for starting the internal combustion engines converts the DC power supplied from the storage device into AC power and supplies the converted AC power to the generator while the first inverter connected to the converter supplies AC power to the first inverter connected to the converter that does not receive a supply of DC power for starting the internal combustion engines.

10. A drive control device according to any one of claims 1 to 8, wherein, when starting the plurality of internal combustion engines, the converter receiving a supply of DC power from the power storage device for starting the internal combustion engines has the first inverter connected to that converter stop supplying AC power to the first inverter connected to the converter not receiving a supply of DC power for starting the internal combustion engines, then converts the DC power supplied from the power storage device into AC power and supplies the converted AC power to the generator.

11. A drive control device according to any one of claims 1 to 10, further comprising: at least one inverter contactor that electrically connects or disconnects the secondary terminal of any one of the first inverters among the plurality of first inverters from the secondary terminal of another one of the first inverters; and a first contactor control unit that closes or opens the inverter contactor.

12. A drive control device as described in claim 11, wherein, when starting the plurality of internal combustion engines, if any of the converters is not receiving a supply of DC power for starting the internal combustion engine, the first contactor control unit closes the inverter contactor that electrically connects the first inverter connected to that converter with another first inverter.

13. A drive control device according to any one of claims 1 to 12, further comprising: at least one storage device contactor provided for each of the storage devices, electrically connecting the storage device to the converter and the primary terminals of the first inverter, or electrically disconnecting the storage device from the converter and the primary terminals of the first inverter; and a second contactor control unit that closes or opens the storage device contactor.

14. A drive control device according to claim 13, wherein the second contactor control unit closes each of the contactors for the power storage device when the plurality of internal combustion engines are started, and when the internal combustion engines start and the power storage device is charged by receiving DC power from the converter connected to the generator driven by the started internal combustion engine, opens the contactor for the power storage device connected to the charged power storage device.

15. A drive control device according to claim 13, wherein the second contactor control unit closes the storage device contactor connected to the storage device in which the amount of stored electric power is equal to or greater than the starting electric power amount when the plurality of internal combustion engines are started.

16. A drive control device according to any one of claims 1 to 15, wherein each of the first inverters has a rectifier circuit that rectifies AC power supplied via the secondary terminals to convert it into DC power and outputs the converted DC power from the primary terminals.

17. A drive control device according to any one of claims 1 to 16, further comprising a power conversion control unit that controls the converter and the first inverter, wherein, at the time of starting the plurality of internal combustion engines, the power conversion control unit controls the converter that receives a supply of DC power for starting the internal combustion engines, so that the converter converts the supplied DC power into AC power and supplies the converted AC power to the generator, and when, at the time of starting the plurality of internal combustion engines, there is a converter that does not receive a supply of DC power for starting the internal combustion engines, the power conversion control unit controls the first inverter connected to the converter that receives a supply of DC power for starting the internal combustion engines, so that the first inverter converts the DC power supplied from the power storage device into AC power and supplies the converted AC power to the first inverter connected to the converter that does not receive a supply of DC power for starting the internal combustion engines.

18. A drive control device according to claim 17, further comprising a plurality of second inverters provided for each of the converters, which, when supplied with DC power from the converter, convert the supplied DC power into AC power to be supplied to the main motor, and supply the converted AC power to the main motor, and the power conversion control unit controls the converters, the first inverter, and the second inverter.

19. The drive control device according to claim 18, wherein the power conversion control section maintains the second inverter in a stopped state until all of the plurality of internal combustion engines have started.

20. A drive control device according to claim 18, wherein, when any of the internal combustion engines is started, the power conversion control unit controls the converter, which receives AC power from the generator driven by the started internal combustion engine, and the second inverter, which receives DC power from the converter, so that the second inverter converts the DC power supplied from the converter into AC power and supplies the converted AC power to the main electric motor.

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