Drive control device

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

Technical Field

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

Background Art

[0002] Some railway vehicles use an internal combustion engine as a power source. 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, a motor that rotates by receiving AC power supply from the inverter, and a drive control device that controls the converter and the inverter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above railway vehicle, in order to start the engine, it is necessary to supply power to the generator, operate the generator as a motor, and transmit the rotational force from the generator operating as a motor to the engine. In order to supply power to the generator, a power storage device capable of storing the power required at the start of the engine is provided. The converter converts the DC power supplied from the power storage device into AC power and supplies the converted AC power to the generator, so that the generator operates as a motor and rotates. The engine starts due to the rotation of the generator.

[0005] If the supply of DC power to the converter is stopped at the start of the engine due to the discharge, failure of the power storage device, disconnection of the power storage device from the converter, etc., the engine cannot be started.

[0006] This disclosure is made in view of the circumstances described above, and aims to provide a drive control device that enables the starting of an internal combustion engine when the supply of DC power to a portion of a converter connected to the internal combustion engine via a generator is stopped. [Means for solving the problem]

[0007] To achieve the above objective, the drive control device of this disclosure is a drive control device for controlling the drive of a railway vehicle powered by a plurality of internal combustion engines, and comprises a plurality of converters, a plurality of first inverters, and at least one energy storage device. A converter is provided for each generator that is provided in accordance with the internal combustion engine and is driven by the internal combustion engine to generate AC power, and performs bidirectional conversion between AC power and DC power. A 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 a supply of AC power, and performs bidirectional conversion between DC power and AC power. The energy storage device has an energy storage capacity greater than the starting power of the internal combustion engine, is connected to the converter and the primary terminal of the first inverter corresponding to the converter, and is charged by the DC power output by the converter or the first inverter. The secondary terminals of the plurality of first inverters are connected to each other. When the plurality of internal combustion engines are started, the converters that receive the DC power to start the internal combustion engines convert the DC power to AC power and supply the converted AC power to the generators. When starting multiple internal combustion engines, a first inverter connected to a converter that is not receiving a DC power supply for starting the internal combustion engines receives AC power generated by a first inverter connected to a power storage device whose stored energy is greater than the starting energy, by converting the DC power supplied from the power storage device. The inverter then converts the supplied AC power back into DC power and outputs the converted DC power from its primary terminal. [Effects of the Invention]

[0008] In the drive control device of this disclosure, when starting multiple internal combustion engines, a first inverter connected to a converter that is not receiving a DC power supply for starting the internal combustion engines converts the AC power supplied from the first inverter, which is connected to a power storage device whose stored energy is greater than the starting energy, into DC power, and outputs the converted DC power from its primary terminal. As a result, each converter receives the DC power supply, converts the DC power into AC power, and supplies the converted AC power to the generator. This provides a drive control device that enables the starting of internal combustion engines when the supply of DC power to some of the converters is stopped. [Brief explanation of the drawing]

[0009] [Figure 1] Block diagram showing the configuration of the drive control device according to Embodiment 1 [Figure 2] Block diagram showing the configuration of the first inverter according to Embodiment 1 [Figure 3] Block diagram showing the configuration of the control unit according to Embodiment 1 [Figure 4] Block diagram showing the hardware configuration of the control unit according to Embodiment 1 [Figure 5] A timing chart showing an example of the engine starting operation performed by the drive control device according to Embodiment 1 when each energy storage device is charged. [Figure 6] A timing chart showing an example of the engine starting operation performed by the drive control device according to Embodiment 1 when some of the energy storage devices are discharged. [Figure 7] This figure shows an example of current flow in the drive control device according to Embodiment 1. [Figure 8] Timing chart showing an example of the engine starting operation performed by the drive control device according to Embodiment 2 when some of the charging devices are discharged. [Figure 9] This figure shows an example of current flow in the drive control device according to Embodiment 2. [Figure 10] Timing chart showing an example of the engine starting operation performed by the drive control device according to Embodiment 3 when some of the charging devices are discharged. [Figure 11] Figure showing an example of the current flow in the drive control device according to Embodiment 3 [Figure 12] Block diagram showing the configuration of the first modification of the drive control device according to the embodiment [Figure 13] Block diagram showing the configuration of the second modification of the drive control device according to the embodiment [Figure 14] Timing chart showing an example of the operation of starting an internal combustion engine performed by the second modification of the drive control device according to the embodiment [Figure 15] Timing chart showing another example of the operation of starting an internal combustion engine performed by the drive control device when some charging devices are in a discharged state [Figure 16] Block diagram showing the configuration of the third modification of the drive control device according to the embodiment [Figure 17] Figure showing an example of the current flow in the third modification of the drive control device according to the embodiment [Figure 18] Figure showing another example of the current flow in the third modification of the drive control device according to the embodiment [Figure 19] Block diagram showing a modification of the hardware configuration of the control unit according to the embodiment

Mode for Carrying Out the Invention

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

[0011] (Embodiment 1) Taking a railway vehicle having a plurality of internal combustion engines as a power source as an example, a drive control device for controlling the drive of the railway vehicle will be described. A railway vehicle drive device 100 for driving a railway vehicle composed of a plurality of vehicles 100a and 100b is shown in FIG. 1.

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

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

[0014] The above-mentioned internal combustion engine 91a, generator 92a, main conversion device 1a, main electric motor 93a, and load device 94a are mounted on vehicle 100a. The above-mentioned internal combustion engine 91b, generator 92b, main conversion device 1b, main electric motor 93b, and load device 94b are mounted on vehicle 100b.

[0015] The internal combustion engines 91a and 91b are diesel engines, gasoline engines, etc. The output shafts of the internal combustion engines 91a and 91b are respectively fixed to the shafts of the generators 92a and 92b. Thereby, at the start of the operation of the railway vehicle, it is possible to start the internal combustion engines 91a and 91b by operating and rotating the generators 92a and 92b as electric motors. After the internal combustion engines 91a and 91b are started, the generators 92a and 92b rotate along with the rotation of the internal combustion engines 91a and 91b and generate AC power. The rotational speeds of the internal combustion engines 91a and 91b are controlled by an internal combustion engine control unit not shown in the figure.

[0016] It should be noted that there is an error in the original text of . The correct sentence structure should be "The drive control device 1 has...". The above translation has been adjusted accordingly.The internal combustion engine control unit acquires a start command signal that changes in response to the operation of a start switch located in the driver's cab, an operation command signal that changes in response to the operation of a master controller located in the driver's cab, and the rotational speeds of the internal combustion engines 91a and 91b measured by a speed sensor (not shown). Based on the start command signal, the operation command signal, and the measured rotational speeds of the internal combustion engines 91a and 91b, the internal combustion engine control unit determines a target rotational speed and performs control to bring the rotational speeds of the internal combustion engines 91a and 91b closer to the target rotational speed.

[0017] When the internal combustion engines 91a and 91b are not running, generators 92a and 92b each operate as electric motors and rotate when they receive AC power from the drive control device 1. After the internal combustion engines 91a and 91b start, generators 92a and 92b are driven by the internal combustion engines 91a and 91b to generate AC power and supply the generated AC power to the drive control device 1. Generators 92a and 92b are, for example, induction generators.

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

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

[0020] The drive control device 1 includes a plurality of converters 11a, 11b provided for each generator 92a, 92b corresponding to the internal combustion engines 91a, 91b, which perform bidirectional conversion between AC power and DC power, and a plurality of first inverters 12a, 12b provided for each converter 11a, 11b, which also perform bidirectional conversion between DC power and AC power. The drive control device 1 includes at least one energy storage device having a storage capacity greater than the starting power of the internal combustion engine 91a or the internal combustion engine 91b; in the example in Figure 1, there are two energy storage devices 13a, 13b. The starting power of the internal combustion engine 91a is the amount of power required by the converter 11a that supplies AC power to the generator 92a in order to start the internal combustion engine 91a. The same applies to the starting power of the internal combustion engine 91b. The drive control device 1 includes second inverters 14a, 14b provided for each converter 11a, 11b.

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

[0022] The converter 11a, the first inverter 12a, the energy storage device 13a, and the second inverter 14a described above are included in the main converter 1a. In addition to the above components, the main converter 1a includes a transformer 16a to which the first inverter 12a is connected as the primary terminal to transform the AC power output by the first inverter 12a into power suitable for the load device 94a, and an AC capacitor 17a connected to the secondary terminal of the transformer 16a. Connection means an electrical connection. The main converter 1a also includes an energy storage device contactor 18a to switch the electrical connection between the energy storage device 13a and the converter 11a, the first inverter 12a, and the second inverter 14a, and an inverter contactor 19a to which one end is connected to the connection point between the AC capacitor 17a and the load device 94a. The main converter 1a includes a control unit 15a that controls the converter 11a, the first inverter 12a, the second inverter 14a, the contactor for the energy storage device 18a, and the contactor for the inverter 19a.

[0023] The converter 11b, first inverter 12b, energy storage device 13b, and second inverter 14b described above are included in the main converter 1b. In addition to the above components, the main converter 1b includes a transformer 16b to which the first inverter 12b is connected as the primary terminal and which transforms the AC power output by the first inverter 12b to make it suitable for the load device 94b, and an AC capacitor 17b connected to the secondary terminal of the transformer 16b. The main converter 1b also includes an energy storage device contactor 18b for switching the electrical connections between the energy storage device 13b and the converter 11b, first inverter 12b, and second inverter 14b, and an inverter contactor 19b to which one end is connected at the connection point between the AC capacitor 17b and the load device 94b. The main converter 1b includes a control unit 15b that controls the converter 11b, the first inverter 12b, the second inverter 14b, the contactor for the energy storage device 18b, and the contactor for the inverter 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, the AC terminals of converter 11a are connected to the output terminals of generator 92a, and the DC terminals of converter 11a are connected to the first inverter 12a, the energy storage device 13a, and the second inverter 14a. The AC terminals of converter 11b are connected to the output terminals of generator 92b, and the DC terminals of converter 11b are connected to the first inverter 12b, the energy storage device 13b, and the second inverter 14b.

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

[0026] The first inverters 12a and 12b are, for example, static inverters in which the output voltage and output frequency are kept constant. 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 the load device 94a via the transformer 16a and the 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 the load device 94b via the transformer 16b and the 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] Since the configurations of the first inverters 12a and 12b are the same, we will describe the details of the first inverter 12a. As shown in Figure 2, the first inverter 12a includes a capacitor C1 whose two terminals are connected to the primary terminals 21a and 22a, switching elements SW1 and SW2 provided between the primary terminals 21a and 22a and connected in series with each other, switching elements SW3 and SW4 provided between the primary terminals 21a and 22a and connected in series with each other, and switching elements SW5 and SW6 provided between the primary terminals 21a and 22a and connected in series with each other.

[0028] Switching elements SW1, SW2, SW3, SW4, and SW5, SW6 correspond to the U-phase, V-phase, and W-phase, respectively. The connection points of switching elements SW1 and SW2 are connected to secondary terminal 23a. The connection points of switching elements SW3 and SW4 are connected to secondary terminal 24a. The connection points of switching elements SW5 and SW6 are connected to secondary terminal 25a. The multiple switching elements SW1-SW6 of the first inverters 12a and 12b are controlled by the control units 15a and 15b, respectively, and repeatedly switched on and off, thereby converting 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), and MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors). In the example in Figure 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 each of the switching elements SW1, SW2, SW3, SW4, SW5, and SW6, respectively.

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

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

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

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

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

[0036] As shown in Figure 1, the energy storage device 13a is connected to the converter 11a, the first inverter 12a, and the second inverter 14a. The energy storage device 13a is charged with the power output by the converter 11a, the first inverter 12a, or the second inverter 14a. Similarly, the energy storage device 13b is connected to the converter 11b, the first inverter 12b, and the second inverter 14b. The energy storage device 13b is charged with the power output by the converter 11b, the first inverter 12b, or the second inverter 14b. Each of the energy storage devices 13a and 13b includes any number of secondary batteries and a monitoring device for monitoring the terminal voltage of the secondary batteries.

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

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

[0039] The transformers 16a and 16b are, for example, delta-star connected transformers that transform the AC power supplied from the first inverters 12a and 12b connected to the primary side to a voltage suitable for the load devices 94a and 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, together with the coils of the transformers 16a and 16b, form an LC filter, thereby reducing the harmonic components generated by the switching operation of the first inverters 12a and 12b.

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

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

[0044] When the contactors 19a and 19b for each inverter are turned on, 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 are electrically connected to each other. More specifically, when the contactors 19a and 19b for each inverter are turned on, the secondary terminals of the transformers 16a and 16b are electrically connected to each other, causing 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 to conduct electricity.

[0045] When the contactors 19a and 19b for each inverter are opened, 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 are electrically disconnected from each other. More specifically, when the contactors 19a and 19b for each inverter are opened, the secondary terminals of the transformers 16a and 16b are electrically disconnected from each other, so that 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 become non-conductive.

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

[0047] Since the configurations of control units 15a and 15b are similar, the configuration of control unit 15a will be described. As shown in Figure 3, control unit 15a includes a first contactor control unit 31 that turns on or off the inverter contactor 19a, a second contactor control unit 32 that turns on or off the energy 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. Control unit 15a includes, for example, a starting determination unit 34 that determines whether the converter 11a is receiving a supply of DC power to start the internal combustion engine 91a using a DC voltage (hereinafter referred to as intermediate link voltage) V1 applied to the electrical circuit between the converter 11a and the first inverter 12a, and a charging determination unit 35 that determines whether the energy storage device 13a is being charged based on, for example, the voltage of the energy 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 driver's cab. The start command signal S1 is, for example, at an L (Low) level when the internal combustion engines 91a and 91b are stopped, and is set to an H (High) level when the internal combustion engines 91a and 91b are started.

[0049] The power conversion control unit 33 receives the operation command signal S2 from the driver's cab. The operation command signal S2 is a signal that indicates, for example, the power notch that instructs the acceleration of the railway vehicle, the brake notch that instructs the deceleration of the railway vehicle, etc. The power conversion control unit 33 receives the status 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 of the control unit 15a acquire the determination result of the starting determination unit 34 of the control unit 15b, and the first contactor control unit 31 of the control unit 15a acquires the determination result of the charging determination unit 35 of the control unit 15b. The determination result of the starting determination unit 34 of the control unit 15b indicates whether the intermediate link voltage V2, which is a DC voltage applied to the electrical circuit between the converter 11b and the first inverter 12b, is sufficient to start the internal combustion engine 91b. The determination result of the charging determination unit 35 indicates whether the energy storage device 13b is charged or not.

[0051] The starting determination unit 34 determines whether the converter 11a is receiving a supply of DC power to start the internal combustion engine 91a. Specifically, the starting determination unit 34 repeatedly obtains 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 assumed that the converter 11a is receiving a supply of DC power to start the internal combustion engine 91a. The starting 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 assumed 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 can be predetermined according to the specifications of the internal combustion engine 91a and the generator 92a.

[0052] The charge determination unit 35 determines whether the energy storage device 13a is sufficiently charged. Specifically, the charge determination unit 35 repeatedly obtains the measured terminal voltage of the secondary battery of the energy storage device 13a from the monitoring device of the energy storage device 13a and determines whether the measured terminal voltage of the secondary battery is equal to or greater than the 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 energy storage device 13a can be considered sufficiently charged. The charge threshold can be determined according to the specifications of the energy storage device 13a.

[0053] As an example of a charging threshold, the charging discrimination unit 35 uses a first charging threshold, which is the voltage value of the energy storage device 13a when the amount of energy stored is twice or more the amount of energy used to start the internal combustion engine 91a, and a second charging threshold, which is lower than the first charging threshold and is the voltage value of the energy storage device 13a when the amount of energy used to start the internal combustion engine 91a is stored.

[0054] Since the hardware configurations of the control units 15a and 15b having the above configurations are similar, the hardware configuration of the control unit 15a will be described. As shown in Figure 4, the control unit 15a comprises a processor 81, a memory 82, and an interface 83. The processor 81, memory 82, and interface 83 are connected to each other by a bus 80. The processor 81 has arbitrary electronic circuits, including transistors, and is considered a circuit or processor circuit. The functions of each part of 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 functions of each part described above are realized by the processor 81 reading and executing the programs stored in the memory 82. That is, the memory 82 stores programs for executing the processing of each part of the control unit 15a.

[0055] Memory 82 includes, for example, non-volatile or volatile semiconductor memories such as RAM (Random Access Memory), ROM (Read-Only Memory), flash memory, EPROM (Erasable Programmable Read Only Memory), EEPROM (Electrically Erasable and Programmable Read-Only Memory), magnetic disks, flexible disks, optical disks, compact disks, minidiscs, DVDs (Digital Versatile Discs), 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 contactor for the energy storage device 18a, and the contactor for the inverter 19a via the interface 83. The interface 83 has one or more interface modules compliant with standards, depending on the connection destination.

[0057] For example, when a railway vehicle parked in a depot is to begin operation, the drive control device 1 having the above configuration starts the internal combustion engines 91a and 91b. In detail, the drive control device 1 converts the DC power stored in the energy storage devices 13a and 13b into AC power using converters 11a and 11b, and supplies the converted AC power to the generators 92a and 92b, causing the generators 92a and 92b to operate as electric motors and rotate. As a result, the internal combustion engines 91a and 91b, whose shafts are fixed to the output shafts of the generators 92a and 92b, rotate and start the internal combustion engines 91a and 91b.

[0058] If one of the energy storage devices 13a or 13b is discharging, it is not possible to supply AC power to one of the generators 92a or 92b, and therefore it is not possible to start one of the internal combustion engines 91a or 91b. In this case, the drive control device 1 uses the power stored in one of the energy storage devices 13a or 13b to supply AC power to both generators 92a or 92b, thereby starting both internal combustion engines 91a or 91b. This provides a drive control device 1 that enables the starting of internal combustion engines 91a or 91b when the supply of DC power to a portion of the converters 11a or 11b is stopped.

[0059] An example of the starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 having the above configuration will be explained using Figures 5 and 6. Figure 5 shows an example of the operation of the drive control device 1 when both energy storage devices 13a and 13b are fully charged. As shown in Graph A, the timing at which the start command signal S1 changes from L level to H level is defined as time T1. At times prior to time T1, the contactors 18a and 18b for the energy storage devices and the contactors 19a and 19b for the inverters are open, and the converters 11a and 11b, the first inverters 12a and 12b, and the second inverters 14a and 14b are stopped. Therefore, at times prior to time T1, the internal combustion engines 91a and 91b, the generators 92a and 92b, the main motors 93a and 93b, and the load devices 94a and 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 close the contactors 18a and 18b for the energy storage device, respectively, as shown in graphs B and F. When contactor 18a for the energy storage device is closed, DC power is supplied from the energy storage device 13a to the converter 11a, and as shown in graph C, at time T1, the voltage of the energy storage device 13a begins to decrease from voltage value Va1. Voltage value Va1 is the voltage value of the energy storage device 13a when it is charged with enough power to start the internal combustion engine 91a. When contactor 18b for the energy storage device is closed, DC power is supplied from the energy storage device 13b to the converter 11b, and as shown in graph G, at time T1, the voltage of the energy storage device 13b begins to decrease from voltage value Vb1. The voltage value Vb1 is the voltage value of the energy storage device 13b when it is charged with enough power to start the internal combustion engine 91b.

[0061] Preferably, each of the energy storage devices 13a and 13b has an energy storage capacity equal to or greater than the sum of the starting power of at least two internal combustion engines 91a and 91b. If the internal combustion engines 91a and 91b are of the same specifications, their starting power can be considered to be the same. For example, the voltage values ​​Va1 and Vb1 are the voltage values ​​of the energy storage devices 13a and 13b when an amount of energy equal to or greater than twice the starting power of the internal combustion engines 91a and 91b is stored. The voltage values ​​Va1 and Vb1 are assumed to coincide with the first charging threshold. After time T1, the capacitors of the converters 11a and 11b are charged by the DC power discharged from the energy storage devices 13a and 13b, and the intermediate link voltages V1 and V2 increase. In other words, the converters 11a and 11b each receive a supply of DC power to start the internal combustion engines 91a and 91b.

[0062] The DC power supplied from the energy storage devices 13a and 13b to the converters 11a and 11b charges the capacitors in the converters 11a and 11b, and the timing when the intermediate link voltages V1 and V2 reach the starting voltage is defined as time T2.

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

[0064] When generators 92a and 92b receive AC power from converters 11a and 11b, they operate as electric motors and rotate. Since the shafts of generators 92a and 92b are fixed to the output shafts of internal combustion engines 91a and 91b, respectively, the internal combustion engines 91a and 91b rotate in conjunction with the rotation of generators 92a and 92b, and the rotational speed of the internal combustion engines 91a and 91b increases as shown in graphs D and H. Subsequently, time T3 is defined as the timing when the rotational speed of the internal combustion engines 91a and 91b reaches the starting rotational speeds R1 and R2, and the internal combustion engines 91a and 91b start. The starting rotational speeds R1 and R2 are rotational speeds at which the internal combustion engines 91a and 91b can be considered to have started, and are determined according to the specifications of the internal combustion engines 91a and 91b. If the internal combustion engines 91a and 91b have the same specifications, the starting rotational speeds R1 and R2 can be considered to be the same value.

[0065] At time T3, after the internal combustion engines 91a and 91b start, when their rotational speed increases to a speed at which generators 92a and 92b can generate electricity, the generators 92a and 92b driven by the internal combustion engines 91a and 91b begin generating electricity. The generators 92a and 92b supply the generated AC power to the converters 11a and 11b.

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

[0067] In detail, the power conversion control unit 33 of the control unit 15a controls multiple switching elements of the converter 11a when the rotational speed of the internal combustion engine 91a, as obtained from the speed sensor, reaches a rotational speed at which power generation by the generator 92a is possible. The converter 11a converts the AC power supplied from the generator 92a, which is driven and generated by the internal combustion engine 91a, into DC power, and supplies the converted DC power to the first inverter 12a, the energy storage device 13a, and the second inverter 14a.

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

[0069] After time T3, the power conversion control unit 33 of the control units 15a and 15b controls 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 energy storage devices 13a and 13b. As a result, the energy storage devices 13a and 13b, which were discharged when the internal combustion engines 91a and 91b were started, are recharged, and as shown in graphs C and G, the voltage of the energy storage device 13a begins to rise from voltage values ​​Va2 and Vb2.

[0070] The voltage value Va2 is lower than the voltage value Va1 and is the voltage value of the energy storage device 13a when it is charged with enough power to start the internal combustion engine 91a. For example, the voltage value Va2 is the voltage value of the energy storage device 13a when it is greater than the starting power of the internal combustion engine 91a and less than twice the starting power. The voltage value Va2 is assumed to coincide with the second charging threshold.

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

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

[0073] The charge discrimination unit 35 in the control units 15a and 15b determines at time T4 that the measured value of the terminal voltage of the secondary batteries in the energy storage devices 13a and 13b is equal to or greater than the first charge threshold. The charge discrimination unit 35 in the control units 15a and 15b sends the discrimination result to the first contactor control unit 31 and the second contactor control unit 32 in the control unit 15a, and to the first contactor control unit 31 and the second contactor control unit 32 in the control unit 15b, respectively.

[0074] At time T4, if the second contactor control unit 32 of the control units 15a and 15b determines that the charge discrimination unit 35 of the control units 15a and 15b has determined that the measured value of the terminal voltage of the secondary batteries of the energy storage devices 13a and 13b is equal to or greater than the first charge threshold, it opens the contactors 18a and 18b for the energy storage devices, as shown in graphs B and F.

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

[0076] After time T3, when the measured values ​​of intermediate link voltages V1 and V2 obtained from the voltage sensors rise to values ​​suitable for the operation of the first inverters 12a and 12b, the power conversion control units 33 of the control units 15a and 15b control multiple switching elements SW1-SW6 of the first inverters 12a and 12b, respectively. Controlled by control unit 15a, the first inverter 12a converts the 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 the operation of the load device 94a. Controlled by control unit 15b, the first inverter 12b converts the 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 enables the operation of the load device 94b.

[0077] After time T3, when the measured values ​​of intermediate link voltages V1 and V2 obtained from the voltage sensors rise to values ​​suitable for the operation of the second inverters 14a and 14b, and the operation command signal S2 indicates a power command, the power conversion control units 33 of the control units 15a and 15b each control multiple switching elements of the second inverters 14a and 14b according to the power command. Controlled by control unit 15a, the second inverter 14a converts the DC power supplied from converter 11a into AC power and supplies the converted AC power to the main motor 93a. The rotation of the main motor 93a, which receives the AC power, generates the propulsion force of the railway vehicle. Controlled by control unit 15b, the second inverter 14b converts the DC power supplied from converter 11b into AC power and supplies the converted AC power to the main motor 93b. The rotation of the main motor 93b, which receives the AC power, generates the propulsion force of the railway vehicle.

[0078] As described above, at time T2, the starting determination unit 34 of the control units 15a and 15b determines that the values ​​of the intermediate link voltages V1 and V2 are equal to or greater than the starting 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 applies to the determination results obtained by the first contactor control unit 31 of the control unit 15b. For this reason, the first contactor control units 31 of the control units 15a and 15b leave the inverter contactors 19a and 19b open, as shown in graphs E and I.

[0079] Figure 6 shows an example of the operation of the drive control device 1 when the energy storage device 13a is fully charged and the energy storage device 13b is discharged. The interpretation of Figure 6 is the same as that of Figure 5. The following describes an example of the starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 when the energy storage device 13a is fully charged and the energy storage device 13b is discharged, focusing on the differences from the operation of the drive control device 1 shown in Figure 5.

[0080] In the main converter 1b, since the energy storage device 13b is in a discharged state, the terminal voltage value of the secondary battery in the energy storage device 13b is sufficiently small at time T1. For example, as shown in graph G, the terminal voltage value of the secondary battery in the energy storage device 13b is voltage value Vb3. Voltage value Vb3 is a value that does not cause over-discharge and allows the energy storage device 13b to be recharged. Even if the contactor 18b for the energy storage device is closed at time T1, since the energy storage device 13b is in a discharged state, sufficient DC power to start the internal combustion engine 91b is not supplied from the energy storage device 13b to the converter 11b. In other words, the supply of DC power to the converter 11b to start the internal combustion engine 91b is stopped.

[0081] Therefore, even at time T11, a certain amount of time has elapsed since time T1, the value of the intermediate link voltage V2 in the main converter 1b does not reach the starting voltage. At time T11, the starting 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, respectively, of the control units 15a and 15b.

[0082] The first contactor control unit 31, which is part of the control units 15a and 15b, electrically connects the first inverters 12a and 12b when either the converters 11a and 11b are not receiving DC power to start the internal combustion engines 91a and 91b. More specifically, the first contactor control unit 31, which is part of the control units 15a and 15b, closes the inverter contactors 19a and 19b when the start command signal S1 is at the H level and the determination result obtained from the start determination unit 34, which is part of the control units 15a and 15b, indicates that at least one of the intermediate link voltages V1 and V2 is less than the start voltage. In the example in Figure 6, when the first contactor control unit 31, which is part of the control units 15a and 15b, obtains a determination result indicating that the intermediate link voltage V2 is less than the start voltage, it closes the inverter contactors 19a and 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 less than the starting voltage, it keeps the converter 11b, the first inverter 12b, and the second inverter 14b all stopped. Therefore, as shown in graph H, at time T11, the rotational speed of the internal combustion engine 91b does not increase, and the internal combustion engine 91b is not started.

[0084] At time T1, the contactor 18a for the energy storage device is closed, so at time T11, DC power is supplied from the energy storage device 13a to the first inverter 12a. 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 energy 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 energy 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, which is connected to converter 11b that is not receiving DC power, are electrically connected to the secondary terminals 23a, 24a, and 25a of the first inverter 12a, which is connected to converter 11a that is 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 the switching elements SW1-SW6 are turned off, the first inverter 12b receives AC power from the first inverter 12a via the secondary terminals 23a, 24a, and 25a. It rectifies the AC power to convert it into DC power and outputs the converted DC power from the primary terminals 21a and 22a. As described above, the converter 11b is stopped and the contactor 18b for the energy storage device is closed. Therefore, as shown by the dotted arrows in Figure 7, the energy storage device 13b is charged by the DC power output by the first inverter 12b.

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

[0088] The charge determination unit 35 of the control unit 15b determines at time T12 that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than 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, supplying power to the first inverter 12a causes the voltage of the energy storage device 13a to decrease, as shown in graph C, but at time T12, enough power to start the internal combustion engine 91a is stored.

[0090] The first contactor control units 31 of control units 15a and 15b open the inverter contactors 19a and 19b after closing the inverter contactors 19a and 19b, respectively, if the determination result of the charge determination unit 35 of control unit 15b indicates that the energy storage device 13b is sufficiently charged. More specifically, as shown in graphs E and I, at time T12, the first contactor control units 31 of control units 15a and 15b open the inverter contactors 19a and 19b if they obtain a determination result indicating that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than the second charge threshold.

[0091] Between times T11 and T12, the capacitor in converter 11b is charged by the DC power supplied from the first inverter 12b, so that at time T12, the intermediate link voltage V2 reaches the starting voltage.

[0092] When the amount of power stored in the respective energy storage devices 13a and 13b at time T12 exceeds the starting power, converters 11a and 11b convert the DC power supplied from the energy storage devices 13a and 13b into AC power, and supply the converted AC power to the generators 92a and 92b. Specifically, at time T12, the starting determination unit 34 of the control unit 15b determines that the measured value of the intermediate link voltage V2 is equal to or greater 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 respective control units 15a and 15b.

[0093] When the inverter contactors 19a and 19b are opened at time T12, the power conversion control unit 33 of the control unit 15a stops the first inverter 12a. Subsequently, when the starting 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 starting voltage, the power conversion control units 33 of the control units 15a and 15b each 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 energy 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 energy storage devices 13a and 13b into AC power and supply the converted AC power to the generators 92a and 92b.

[0094] Subsequently, similar to the example in Figure 5, the rotational speeds of the internal combustion engines 91a and 91b increase. Time T13 is defined as the timing when the rotational speeds of the internal combustion engines 91a and 91b reach their respective starting rotational speeds R1 and R2.

[0095] At time T13, after the internal combustion engines 91a and 91b start, when their rotational speeds increase to a speed at which generators 92a and 92b can generate electricity, the generators 92a and 92b driven by the internal combustion engines 91a and 91b begin generating electricity. The generators 92a and 92b supply the generated AC power to the converters 11a and 11b.

[0096] Because discharge occurs between time T12 and time T13, the voltages of the energy storage devices 13a and 13b drop to voltage values ​​Va3 and Vb3 at time T13. Voltage values ​​Va3 and Vb3 are values ​​that allow for recharging of the energy storage devices 13a and 13b without over-discharge.

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

[0098] As explained above, according to the drive control device 1 of Embodiment 1, even when either the energy storage device 13a or 13b is discharging and therefore neither the converter 11a or 11b is receiving DC power, both the internal combustion engines 91a and 91b can be started.

[0099] (Embodiment 2) The method for starting the internal combustion engines 91a and 91b is not limited to the examples described above. Embodiment 2 describes a drive control device 1 that starts the internal combustion engines 91a and 91b in a different way than that described in Embodiment 1. The configuration of the drive control device 1 according to Embodiment 2 is the same as that of Embodiment 1.

[0100] The starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 when both energy storage devices 13a and 13b are fully charged is the same as the starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 according to Embodiment 1 shown in Figure 5. An example of the operation of the drive control device 1 when energy storage device 13a is fully charged and energy storage device 13b is discharged is shown in Figure 8. The way to read Figure 8 is the same as the way to read Figure 6. The operation of the drive control device 1 from time T1 to time T11 is the same as the operation of the drive control device 1 according to Embodiment 1 shown in Figure 6.

[0101] At time T11, the starting determination unit 34 of the control unit 15a determines that the measured value of the intermediate link voltage V1 is equal to or greater 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. When the determination result of the starting determination unit 34 indicates that the measured value of the intermediate link voltage V1 is equal to or greater than the starting voltage, the power conversion control unit 33 of 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 energy 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. Since the shaft of the generator 92a is fixed to the output shaft of the internal combustion engine 91a, the internal combustion engine 91a rotates in conjunction with the rotation of the generator 92a, and the rotational speed of the internal combustion engine 91a increases as shown in graph D. Subsequently, the rotational speed of the internal combustion engine 91a reaches the starting 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 closed, 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 energy 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] From time T21 onward, the energy storage device 13a supplies power to the operating converter 11a and the first inverter 12a, as shown by the solid arrows in Figure 9. In other words, the converter 11a, which is receiving DC power, converts the DC power supplied from the energy storage device 13a into AC power while the first inverter 12a connected to the converter 11a is supplying AC power to the first inverter 12b connected to the converter 11b, which is not receiving DC power, and supplies the converted AC power to the generator 92a. In this way, the main converter 1a starts the internal combustion engine 91a and supplies power to the main converter 1b in parallel, so the voltage of the energy storage device 13a decreases, as shown in graph C in Figure 8.

[0105] At time T21, the internal combustion engine 91a starts, and the rotational speed of the internal combustion engine 91a increases until it reaches a rotational speed at which the generator 92a can generate electricity, which is defined as 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 of 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 AC power supplied from the generator 92a, which is driven by the internal combustion engine 91a, into DC power, and supplies the converted DC power to the energy storage device 13a and the first inverter 12a. As a result, the discharged energy storage device 13a is recharged, and the voltage value of the energy storage device 13a begins to rise, as shown in graph C. The first inverter 12a also 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 DC power supplied from the converter 11a charges the energy storage device 13a, and as shown in graph C, the voltage of the energy storage device 13a begins to rise. Subsequently, the measured voltage across the terminals of the secondary battery in the energy storage device 13a reaches the voltage value Va1, and the timing when the charging of the energy storage device 13a is completed is defined as time T25. In other words, at time T25, the energy storage device 13a is charged with enough power to start the internal combustion engines 91a and 91b next.

[0108] The charge determination unit 35 of the control unit 15a determines at time T25 that the measured value of the terminal voltage of the secondary battery of the energy storage device 13a is equal to or greater than 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 a determination result from the charge determination unit 35 of the control unit 15a at time T25 indicating that the measured value of the terminal voltage of the secondary battery of the energy storage device 13a is equal to or greater than the first charge threshold, it opens the contactor 18a for the energy storage device, as shown in Graph B.

[0110] As described above, the first inverter 12b, which receives AC power from the first inverter 12a, converts the supplied AC power into DC power by rectifying it with the switching elements SW1-SW6 turned off, and outputs the converted DC power. As described above, the converter 11b is stopped and the contactor 18b for the energy storage device is closed, so the energy 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, as shown in graph G of Figure 8, the voltage of the energy storage device 13b begins to rise. The time when the voltage of the energy storage device 13b reaches the voltage value Vb1 is defined as time T23. In other words, at time T23, the energy storage device 13b is charged with enough power to start the internal combustion engine 91b.

[0112] The charge determination unit 35 of the control unit 15b determines at time T23 that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than 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] The first contactor control units 31 of control units 15a and 15b open the inverter contactors 19a and 19b after closing the inverter contactors 19a and 19b, respectively, if the determination result of the charge determination unit 35 of control unit 15b indicates that the energy storage device 13b is sufficiently charged. More specifically, the first contactor control units 31 of control units 15a and 15b open the inverter contactors 19a and 19b at time T23, as shown in graphs E and I, when they obtain a determination result indicating that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than the first charge threshold.

[0114] By time T23, the capacitor in converter 11b is charged by the DC power supplied from the first inverter 12b, so at time T23, the intermediate link voltage V2 has reached the starting voltage.

[0115] At time T23, 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 greater than the start 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.

[0116] When the inverter contactors 19a and 19b are opened at time T23, the power conversion control unit 33 of 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 energy 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 in response to the AC power supply, causes the internal combustion engine 91b to rotate, and as shown in graph H, the rotational speed of the internal combustion engine 91b increases. Time T24 is defined as the timing when the rotational speed of the internal combustion engine 91b reaches the starting rotational speed R2.

[0117] At time T24, after the internal combustion engine 91b starts, when the rotational speed of the internal combustion engine 91b increases to a 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 to DC power and supplies the converted DC power to energy storage device 13b. As a result, the discharged energy storage device 13b is recharged, and as shown in graph G, at time T25, the voltage of energy storage device 13b begins to rise. Subsequently, at time T26, the voltage of energy storage device 13b reaches voltage value Vb1, and the charging of energy storage device 13b is completed. In other words, at time T26, energy storage device 13b is charged with enough power to start the internal combustion engine 91b next.

[0119] The charge determination unit 35 of the control unit 15b determines at time T26 that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than 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] At time T26, when the second contactor control unit 32 of the control unit 15b obtains 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 energy storage device 13b is equal to or greater than the first charge threshold, it opens the contactor 18b for the energy storage device, as shown in graph F.

[0121] As explained above, according to the drive control device 1 of Embodiment 2, even when either the energy storage device 13a or 13b is discharging and therefore neither the converter 11a or 11b is receiving DC power, both the internal combustion engines 91a and 91b can be started.

[0122] Furthermore, while the first inverter 12a connected to the converter 11a is supplying AC power to the first inverter 12b connected to the converter 11b which is not receiving DC power, the converter 11a converts the DC power supplied from the energy storage device 13a into AC power and supplies the converted AC power to the generator 92a. As described above, the drive control device 1 charges the discharged energy storage device 13b while starting the internal combustion engine 91a first, making it possible to quickly start the startable internal combustion engine 91a.

[0123] (Embodiment 3) The method for starting the internal combustion engines 91a and 91b is not limited to the examples described above. Embodiment 3 describes a drive control device 1 that starts the internal combustion engines 91a and 91b in a different manner from Embodiments 1 and 2. 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 of the control units 15a and 15b acquires the rotational speed of the internal combustion engines 91a and 91b from the speed sensor, and the second contactor control unit 32 of the control units 15a and 15b acquires the determination result from the starting determination unit 34.

[0124] The starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 when both energy storage devices 13a and 13b are fully charged is the same as the starting process for the internal combustion engines 91a and 91b performed by the drive control device 1 according to Embodiment 1 shown in Figure 5. An example of the operation of the drive control device 1 when energy storage device 13a is fully charged and energy storage device 13b is discharged is shown in Figure 10. The way to read Figure 10 is the same as the way to read Figure 6. The operation of the main converter 1a provided in the drive control device 1 according to Embodiment 3 is the same as the operation of the main converter 1a provided in the drive control device 1 according to Embodiment 2 shown in Figure 8.

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

[0126] Therefore, even at time T11, the value of the intermediate link voltage V2 in the main converter 1b does not reach the starting voltage. At time T11, the starting 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 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, it opens the contactor 18b for the energy storage device, as shown in graph F.

[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 less than the starting voltage, it keeps the converter 11b, the first inverter 12b, and the second inverter 14b all stopped. Therefore, as shown in graph H, at time T11 when the rotational speed of the internal combustion engine 91a begins to increase, the rotational speed of the internal combustion engine 91b does not increase, and the internal combustion engine 91b is not started.

[0130] From time T11 onward, when the first inverter 12b receives AC power from the first inverter 12a via the secondary terminals 23a, 24a, and 25a with the switching elements SW1-SW6 turned off, it rectifies the AC power to convert it into DC power and outputs the converted DC power from the primary terminals 21a and 22a.

[0131] Since the contactor 18b for the energy storage device is open, the capacitor in the converter 11b is charged by the DC power supplied from the first inverter 12b, as shown by the dotted arrow in Figure 11. When the starting determination unit 34 in the control unit 15b determines that the measured value of the intermediate link voltage V2 is equal to or greater than the starting voltage, it 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.

[0132] When the starting determination unit 34 obtains a determination result indicating that the measured value of the intermediate link voltage V2 is equal to or greater than the starting voltage, the power conversion control unit 33 of 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 in response to the AC power supply, causes the internal combustion engine 91b to rotate, and as shown in graph H, the rotational speed of the internal combustion engine 91b increases. At time T22, the rotational speed of the internal combustion engine 91b reaches the starting rotational speed R2.

[0133] At time T22, the internal combustion engine 91b starts, and the timing at which the rotational speed of the internal combustion engine 91b increases to a rotational speed at which the generator 92b can generate electricity is defined as 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 rotational speeds of the internal combustion engines 91a and 91b are equal to or greater than the rotational speed at which the generators 92a and 92b can generate electricity, so the first contactor control unit 31 of the control units 15a and 15b opens the inverter contactors 19a and 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 energy storage device 13b, and the second inverter 14b. As a result, the energy storage device 13b is charged, and as shown in graph G, at time T31, the voltage of the energy storage device 13b begins to rise. Subsequently, at time T32, the voltage of the energy storage device 13b reaches the voltage value Vb1, and the charging of the energy storage device 13b is completed. In other words, at time T32, the energy storage device 13b is charged with enough power to start the internal combustion engine 91b next.

[0135] The charge determination unit 35 of the control unit 15b determines at time T32 that the measured value of the terminal voltage of the secondary battery of the energy storage device 13b is equal to or greater than 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] At time T32, if the second contactor control unit 32 of the control unit 15b determines that 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 energy 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 contactor 18b for the energy storage device, as shown in graph F.

[0137] As explained above, according to the drive control device 1 of Embodiment 3, even when either the energy storage device 13a or 13b is discharging and therefore neither the converter 11a or 11b is receiving DC power, both the internal combustion engines 91a and 91b can be started.

[0138] Furthermore, while the first inverter 12a connected to converter 11a is supplying AC power to the first inverter 12b connected to converter 11b, which is not receiving DC power, converter 11a converts the DC power supplied from the energy storage device 13a into AC power and supplies the converted AC power to the generator 92a. As a result, the drive control device 1 starts the internal combustion engine 91a first, while simultaneously supplying power to converter 11b to start the internal combustion engine 91b, thus enabling the startable internal combustion engine 91a to start quickly. In the main converter 1b, the internal combustion engine 91b is started before the energy storage device 13b is charged, enabling the rapid starting of both internal combustion engines 91a and 91b.

[0139] This disclosure is not limited to the examples described above. The circuit configuration described above is just one example and can be changed at will. For example, the circuit configuration of the first inverters 12a and 12b is not limited to the example in Figure 2, and any circuit that can convert DC power supplied from converters 11a and 11b into AC power, and convert AC power supplied from the other first inverters 12a and 12b into DC power, is acceptable.

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

[0141] As in Embodiment 1, even if the output voltage of the converters 11a and 11b rises to a value suitable for the first inverters 12a and 12b and the second inverters 14a and 14b immediately after starting the internal combustion engines 91a and 91b, the DC / DC converters 41a and 41b supply the stepped-down DC power to the energy storage devices 13a and 13b. Therefore, it is not necessary to make the energy storage devices 13a and 13b large enough to withstand high voltages. This makes it possible to suppress the increase in size of the drive control device 2.

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

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

[0144] Since the DC / DC converters 41a and 41b operate as boost circuits, it is not necessary to make the energy storage devices 13a and 13b large-capacity devices capable of operating the first inverters 12a and 12b. This makes it possible to suppress the increase in size of the drive control device 2.

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

[0146] As another example, Figure 13 shows a drive control device 3 having only one energy storage device 13a. In the drive control device 3, the main converter 3a is equipped with the energy storage device 13a, but the main converter 3b is not equipped with an energy storage device or a contactor for the energy storage device. The first contactor control unit 31, which is included in the control units 15a and 15b, acquires the rotational speed of the internal combustion engines 91a and 91b from the speed sensor. As shown in Figure 14, when the start command signal S1 reaches the H level at time T1, the first contactor control unit 31, which is included in the control units 15a and 15b of the drive control device 3, closes the inverter contactors 19a and 19b, as shown in graphs E and G.

[0147] Subsequently, similar to Embodiment 3, the internal combustion engine 91a starts at time T21, and the internal combustion engine 91b starts at time T22. At time T31, when the rotational speed of the internal combustion engine 91b reaches a rotational speed at which power generation by the generator 92b is possible, the first contactor control unit 31 of the control units 15a and 15b opens the inverter contactors 19a and 19b.

[0148] The method for starting the internal combustion engines 91a and 91b is not limited to the examples described above. For example, the drive control device 1 according to Embodiment 3 does not need to charge the energy storage device 13b when the energy storage device 13b is malfunctioning. More specifically, as shown in Figure 15, the second contactor control unit 32 of the control unit 15b of the drive control device 1 may leave the contactor 18b for the energy storage device open, as shown in Graph G, if the voltage value of the terminal voltage of the energy storage device 13b at time T1 is less than the second charging threshold. In this case as well, it is possible to start both the internal combustion engines 91a and 91b with the power stored in the energy storage device 13a.

[0149] In the method of starting the internal combustion engines 91a and 91b shown in Figure 6, the timing of starting the internal combustion engines 91a and 91b is the same, but the timing of starting the internal combustion engines 91a and 91b may be different. For example, the power conversion control unit 33 provided in the control unit 15a may acquire the rotational speed of the internal combustion engine 91b from the speed sensor and start controlling the converter 11a after the internal combustion engine 91b has started to rotate. As a result, the rotational speed of the internal combustion engine 91a will start to increase after the rotational speed of the internal combustion engine 91b has started to increase.

[0150] In the method for starting the internal combustion engines 91a and 91b shown in Figure 10, the inverter contactors 19a and 19b are opened at time T31 when the internal combustion engine 91b starts and power generation by the generator 92b becomes possible. However, the inverter contactors 19a and 19b may be opened at a later time than T31. For example, the inverter contactors 19a and 19b may be opened at time T32 when the charging of the energy storage device 13b is completed.

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

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

[0153] When the start command signal S1 changes from L level to H level, the drive control device 1 may output a message to a display device installed in the driver's cab indicating that charging is complete when the charging of either the energy storage device 13a or 13b, which was discharging at that time, is complete, prompting the driver to stop and restart the drive control device 1. Since the energy storage device 13a or 13b, which was discharging, is now charged, in other words, both energy storage devices 13a and 13b are sufficiently charged, restarting the drive control device 1 will start both the internal combustion engines 91a and 91b.

[0154] As another example, immediately after starting the internal combustion engines 91a and 91b, the output voltages of the converters 11a and 11b may be maintained at a value suitable for the energy storage devices 13a and 13b, which is lower than the value suitable for the first inverters 12a and 12b and the second inverters 14a and 14b, thereby charging the energy storage devices 13a and 13b. In this case, the power conversion control units 33 of the control units 15a and 15b may, when the determination result of the charge determination unit 35 indicates that the charging of the energy storage devices 13a and 13b is complete, increase the output voltages of the converters 11a and 11b to a value suitable for the first inverters 12a and 12b and the second inverters 14a and 14b, and operate the first inverters 12a and 12b and the second inverters 14a and 14b.

[0155] As another example, the starting determination unit 34 of the control units 15a and 15b may determine from the voltage value of the terminal voltage of the energy storage devices 13a and 13b whether or not the converters 11a and 11b are receiving DC power to start the internal combustion engines 91a and 91b.

[0156] The operation of the internal combustion engines 91a and 91b after starting is not limited to the examples described above. When the first inverters 12a and 12b operate synchronously, the first contactor control unit 31 of the control units 15a and 15b may close the inverter contactors 19a and 19b immediately after starting the internal combustion engines 91a and 91b.

[0157] In the drive control device 1 shown in Embodiment 2, when only the internal combustion engine 91a is running, the power conversion control unit 33 of the control unit 15a, upon acquiring the driving command signal S2 indicating a traction command, may control multiple switching elements of the second inverter 14a regardless of the determination result acquired from the starting determination unit 34 of the control unit 15b. As a result, the second inverter 14a converts DC power to AC power and supplies the converted AC power to the main motor 93a. The main motor 93a, upon receiving the AC power, generates the propulsion force for the railway vehicle. As a result, it becomes possible to run the railway vehicle even when only the internal combustion engine 91a is running.

[0158] The number of internal combustion engines and main converters mounted on a single railway vehicle is not limited to the example above, and can be any number of two or more. Figure 16 shows a railway vehicle drive system 200 that drives a railway vehicle composed of vehicles 100a, 100b, and 100c. In addition to the configuration of the railway vehicle drive system 100, the 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 main motor 93c that generates propulsion for the railway vehicle by rotating in response to the supply of AC power, and a load device 94c that operates in response to the supply of AC power.

[0159] The drive control device 4 provided in the railway vehicle drive system 200 includes three main converters 1a, 1b, and 1c. The configurations of the main converters 1a and 1b are the same as in Embodiment 1. The configuration of the main converter 1c is the same as that of the main converters 1a and 1b, with the addition of an inverter contactor 20c. In detail, the main converter 1c includes a converter 11c that converts AC power supplied from the 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 the 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 converter 1c includes a contactor 18c for the energy storage device, which switches the electrical connection between the energy storage device 13c, the converter 11c, the first inverter 12c, and the second inverter 14c, and contactors 19c and 20c for the inverters. The main converter 1c also includes a control unit 15c that controls the converter 11c, the first inverter 12c, the second inverter 14c, the contactor 18c for the energy storage device, and the contactor 19c for the inverters.

[0160] The main converter 1c is mounted on the vehicle 100c. In Figure 16, to avoid complicating the diagram, the primary terminals (DC side terminals) and secondary terminals (AC side terminals) of the first inverters 12a, 12b, and 12c, as well as the transformers and AC capacitors connected to the secondary terminals of the first inverters 12a, 12b, and 12c, have been omitted.

[0161] When the energy storage device 13c is in a discharged state, for example, as shown by the solid arrows in Figure 17, the first inverter 12a supplies AC power to the first inverter 12c via the inverter contactors 19a and 19c. 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 Figure 17, when the energy storage device 13c is charged with the DC power output by the first inverter 12c, it becomes possible to store enough power in the energy storage device 13c to start the internal combustion engine 91c next.

[0162] When the energy storage device 13b is in a discharged state, for example, as shown by the solid arrows in Figure 18, the first inverter 12c supplies AC power to the first inverter 12b via the inverter contactors 20c and 19b. 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 arrows in Figure 18, when the energy storage device 13b is charged with the DC power output by the first inverter 12b, it becomes possible to store enough power in the energy storage device 13b to start the internal combustion engine 91b next.

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

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

[0165] If the processing circuit 84 is dedicated hardware, the processing circuit 84 may be, 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 part of the control units 15a and 15b may be implemented by individual processing circuits 84, or by a common processing circuit 84.

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

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

[0168] The drive control device 1-4 is not limited to railway vehicles, but may be installed on any mobile vehicle powered by multiple internal combustion engines, such as a trolleybus.

[0169] This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of this disclosure. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of this disclosure. In other words, the scope of this disclosure is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of the disclosure are considered to be within the scope of this disclosure. [Explanation of Symbols]

[0170] 1,2,3,4 Drive control device, 1a,1b,1c,2a,2b,3a,3b Main converter, 11a,11b,11c Converter, 12a,12b,12c First inverter, 13a,13b,13c Energy storage device, 14a,14b,14c Second inverter, 15a,15b,15c Control unit, 16a,16b Transformer, 17a,17b AC capacitor, 18a,18b,18c Contactor for energy storage device, 19a,19b,19c,20c Contactor for inverter, 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 35 Start detection 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 Main motor, 94a, 94b, 94c Load device, 100, 200 Drive system for railway vehicles, 100a, 100b, 100c Vehicle, C1 Capacitor, D1, D2, D3, D4, D5, D6 Freewheeling 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 multiple internal combustion engines, A plurality of converters are provided for each generator that is provided in accordance with the internal combustion engine and is driven by the internal combustion engine to generate AC power, and which perform bidirectional conversion between AC power and DC power. Each of the converters is provided with a plurality of first inverters, each having a primary terminal connected to the converter and a secondary terminal connected to a load device that operates by receiving AC power, and performing bidirectional conversion between DC power and AC power. The system comprises at least one energy storage device having an energy storage capacity greater than the starting power of the internal combustion engine, connected to the converter and the primary terminal of the first inverter corresponding to the converter, and charged by the DC power output by the converter or the first inverter, The secondary terminals of the plurality of first inverters are connected to each other. When the multiple internal combustion engines are started, the converter, which is receiving a supply of DC power to start the internal combustion engines, converts the DC power to AC power and supplies the converted AC power to the generator. The first inverter, which is connected to the converter that is not receiving a supply of DC power to start the internal combustion engines, receives AC power generated by the first inverter, which is connected to a power storage device whose stored energy is greater than the starting energy, by converting the DC power supplied from the power storage device. The first inverter converts the supplied AC power to DC power and outputs the converted DC power from the primary terminal. Drive control device.

2. Each converter is provided with a plurality of energy storage devices, When starting the multiple internal combustion engines, the first inverter connected to the converter, which is not receiving a supply of DC power to start the internal combustion engines, receives AC power generated by the first inverter connected to the energy storage device, which has a stored amount of power greater than the starting power, by converting the DC power supplied from the energy storage device, converts the supplied AC power back into DC power, and supplies the converted DC power to the energy storage device. The drive control device according to claim 1.

3. When starting the aforementioned multiple internal combustion engines, if the amount of electricity stored in each of the energy storage devices is equal to or greater than the starting power amount, each converter converts the DC power supplied from the energy storage device into AC power and supplies the converted AC power to the generator. The drive control device according to claim 2.

4. Each of the aforementioned energy storage devices is provided with at least one step-down circuit that is connected to the primary terminal of the first inverter and steps down the DC power supplied from the connected first inverter and supplies it to the energy storage device. When starting the multiple internal combustion engines, the first inverter connected to the converter, which is not receiving a DC power supply for starting the internal combustion engines, receives AC power from the first inverter connected to the energy storage device, which has a stored amount of power greater than the starting power amount, converts the supplied AC power to DC power, and supplies the converted DC power to the energy storage device via the step-down circuit. The drive control device according to claim 2 or 3.

5. The step-down circuit is further connected to the converter. When the internal combustion engine starts, the converter converts the 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 energy storage device via the step-down circuit. The drive control device according to claim 4.

6. Equipped with one of the aforementioned energy storage devices, When the multiple internal combustion engines are started, the first inverter connected to the energy storage device converts the DC power supplied from the energy storage device into AC power, outputs the converted AC power from the secondary terminal, and the first inverter receiving the AC power output from the secondary terminal of the first inverter connected to the energy storage device converts the supplied AC power into DC power, and supplies the converted DC power to the converter. The drive control device according to claim 1.

7. The energy storage device has an energy storage capacity equal to or greater than the sum of the starting power amounts of at least two of the internal combustion engines. When starting the multiple internal combustion engines, the first inverter connected to the converter, which is not receiving a supply of DC power to start the internal combustion engines, receives AC power generated by the first inverter, which is connected to the energy storage device, where the amount of stored energy is equal to or greater than the sum of the starting power amounts of at least two of the internal combustion engines, by converting the DC power supplied from the energy storage device. The first inverter then converts the supplied AC power back into DC power and outputs the converted DC power from the primary terminal. A drive control device according to any one of claims 1-3, 6.

8. Each of the aforementioned energy storage devices is provided with at least one boost circuit that is connected to the energy storage device and the primary terminal of the first inverter, and further boosts the DC power output by the energy storage device and supplies it to the first inverter. A drive control device according to any one of claims 1-3, 6.

9. When starting the multiple internal combustion engines, the converter, which is receiving DC power from the energy storage device to start the internal combustion engines, converts the DC power supplied from the energy storage device to AC power while the first inverter connected to the converter is supplying AC power to the first inverter connected to the converter that is not receiving DC power to start the internal combustion engines, and supplies the converted AC power to the generator. A drive control device according to any one of claims 1-3, 6.

10. When starting the multiple internal combustion engines, the converter, which is receiving DC power from the energy storage device to start the internal combustion engines, first has the first inverter connected to the converter stop supplying AC power to the first inverter connected to the converter that is not receiving DC power to start the internal combustion engines, then converts the DC power supplied from the energy storage device into AC power, and supplies the converted AC power to the generator. A drive control device according to any one of claims 1-3, 6.

11. At least one inverter contactor that electrically connects or disconnects the secondary terminal of one of the plurality of first inverters from the secondary terminal of another first inverter, The system further comprises a first contactor control unit for closing or opening the aforementioned inverter contactor, A drive control device according to any one of claims 1-3, 6.

12. When starting the plurality of internal combustion engines, if any of the converters is not receiving DC power to start the internal combustion engine, the first contactor control unit closes the inverter contactor that electrically connects the first inverter connected to the converter with the other first inverters. The drive control device according to claim 11.

13. Each of the energy storage devices is provided with at least one contactor for the energy storage device, which electrically connects the energy storage device to the converter and the primary terminal of the first inverter, or electrically disconnects the energy storage device from the converter and the primary terminal of the first inverter. A second contactor control unit that closes or opens the contactor for the energy storage device, A drive control device according to any one of claims 1, 3, or 6, further comprising:

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

15. The second contactor control unit, when starting the plurality of internal combustion engines, closes the contactor for the energy storage device that is connected to the energy storage device, the amount of stored energy being equal to or greater than the starting energy amount. The drive control device according to claim 13.

16. Each of the first inverters has a rectifier circuit that converts AC power supplied via the secondary terminal into DC power by rectification, and outputs the converted DC power from the primary terminal. A drive control device according to any one of claims 1-3, 6.

17. The power conversion control unit further comprises the converter and the first inverter, When starting the multiple internal combustion engines, the power conversion control unit controls the converter that receives the DC power supply 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. When starting the multiple internal combustion engines, if there is a converter that is not receiving a DC power supply for starting the internal combustion engines, the power conversion control unit controls the first inverter connected to the converter that is receiving a DC power supply for starting the internal combustion engines, so that the first inverter converts the DC power supplied from the energy storage device into AC power and supplies the converted AC power to the first inverter connected to the converter that is not receiving a DC power supply for starting the internal combustion engines. A drive control device according to any one of claims 1-3, 6.

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

19. Until all of the aforementioned internal combustion engines have started, the power conversion control unit will keep the second inverter in a stopped state. The drive control device according to claim 18.

20. When any of the internal combustion engines starts, 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. The second inverter converts the DC power supplied by the converter into AC power and supplies the converted AC power to the main motor. The drive control device according to claim 18.

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