Regenerative power utilization system, control method, and program

Abstract

The purpose of the present disclosure is to make improvements relating to utilization of regenerative power. At least two types of motor system (5) include a first motor system (51) that has one or more first motors (M11), and a second motor system (52) that has one or more second motors (M12) having a higher voltage specification than the one or more first motors (M11). A regenerative power utilization system (1) comprises a step-up / step-down power conversion circuit (2), an energy storage device (3), and a control unit (4). The power conversion circuit (2) is connected between a first bus line (B1) and a second bus line (B2), the power conversion circuit (2) executing switching operations relating to a plurality of switch elements (SW0). The energy storage device (3) is connected to the power conversion circuit (2). The control unit (4) controls the plurality of switch elements (SW0) so that the energy storage device (3) is charged by regenerative power. When specific conditions are satisfied, the control unit (4) controls the plurality of switch elements (SW0) so that the stored power in the energy storage device (3) is used as power for powering the first motor system (51).

Description

Regenerative power utilization system, control method, and program

[0001] The present disclosure generally relates to a regenerative power utilization system, a control method, and a program, and more particularly, to a regenerative power utilization system, a control method, and a program that utilizes regenerative power generated by a motor.

[0002] Patent Document 1 discloses a multi-axis drive device used to individually drive multiple motors. In this multi-axis drive device, when a control unit issues a power assist command to an inverter circuit, the inverter circuit stores the increase in bus voltage in a bus voltage smoothing capacitor to effectively utilize regenerative power. According to Patent Document 1, a portion of the existing bus voltage smoothing capacitor in the multi-axis drive device can be used as a storage device for storing regenerative power, which has the advantage of eliminating the need for additional storage devices.

[0003] International Publication No. 2014 / 167648

[0004] Incidentally, the regenerative power generated in a motor system having a motor with a relatively low voltage specification (for example, 48 V) is difficult to utilize efficiently because the amount of power generated by each motor is small, and in reality, the regenerative power is wasted within the motor system. However, as the number of motors in a motor system increases, the amount of wasted regenerative power also increases, and so in large-scale systems, it is desirable to be able to utilize this regenerative power as well.

[0005] The present disclosure has been made in view of the above circumstances, and aims to provide a regenerative power utilization system, a control method, and a program that can improve utilization of regenerative power.

[0006] A regenerative power utilization system according to one aspect of the present disclosure is configured to utilize regenerative power generated by at least two types of motor systems. The at least two types of motor systems include a first motor system having one or more first motors and a second motor system having one or more second motors with a higher voltage specification than the one or more first motors. The regenerative power utilization system includes a step-up / step-down power conversion circuit, a power storage device, and a control unit. The power conversion circuit is connected between a first bus line for supplying power to the first motor system and a second bus line for supplying power to the second motor system. The power conversion circuit has multiple switch elements and performs switching operations on the multiple switch elements. The power storage device is connected to the power conversion circuit on the first bus line side or the second bus line side of the power conversion circuit. The control unit controls the multiple switch elements to charge the power storage device with the regenerative power. When a specific condition is met, the control unit controls the multiple switch elements so that the stored power in the power storage device is used to power the first motor system.

[0007] A control method according to one aspect of the present disclosure relates to utilization of regenerative power generated in at least two types of motor systems. The at least two types of motor systems include a first motor system having one or more first motors and a second motor system having one or more second motors with a higher voltage specification than the one or more first motors. The control method includes a first control step and a second control step. The first control step includes controlling a plurality of switch elements in a buck-boost power conversion circuit that has a plurality of switch elements and performs switching operations on the plurality of switch elements to charge a power storage device with the regenerative power. The power conversion circuit is connected between a first bus line for supplying power to the first motor system and a second bus line for supplying power to the second motor system. The power storage device is connected to the power conversion circuit on the side of the first bus line or the side of the second bus line relative to the power conversion circuit. The second control step includes controlling the plurality of switch elements so that the stored power in the power storage device is used to power the first motor system when a specific condition is met.

[0008] A program according to one aspect of the present disclosure is a program for causing one or more processors to execute the above-described control method.

[0009] FIG. 1A is a circuit diagram of an entire system including a regenerative power utilization system according to one embodiment. FIG. 1B is a block diagram of a control unit included in the regenerative power utilization system. FIG. 2 is a flowchart illustrating operations related to determining a control mode in the regenerative power utilization system. FIG. 3 is a flowchart illustrating operations related to a charge mode in the regenerative power utilization system. FIG. 4 is a flowchart illustrating operations related to a discharge mode in the regenerative power utilization system. FIG. 5 is a circuit diagram of a first modified example of the regenerative power utilization system. FIG. 6 is a schematic circuit diagram of an entire system including a second modified example of the regenerative power utilization system. FIG. 7 is a schematic circuit diagram of an entire system including a third modified example of the regenerative power utilization system.

[0010] (Summary) Regenerative power utilization systems according to embodiments and modifications will be described below with reference to the drawings. Note that the following embodiments and modifications are merely examples of various embodiments of the present disclosure. Furthermore, the following embodiments and modifications can be modified in various ways depending on the design, etc., as long as the object of the present disclosure can be achieved. Furthermore, the configurations of the modifications can be combined as appropriate.

[0011] The drawings described in the following embodiments and modifications are schematic, and the ratios of the sizes and thicknesses of the components do not necessarily reflect the actual dimensional ratios.

[0012] As shown in FIG. 1A , a regenerative power utilization system 1 according to one embodiment is configured to utilize regenerative power generated by at least two types of motor systems 5. The at least two types of motor systems 5 include a first motor system 51 having one or more (three in FIG. 1A ) first motors M11 and a second motor system 52 having one or more (three in FIG. 1A ) second motors M12. However, the one or more second motors M12 have a higher voltage specification than the one or more first motors M11. In the following embodiment, as an example, the regenerative power utilization system 1 is applied to the first motor system 51 and the second motor system 52 and is configured to utilize regenerative power generated by these motor systems 5. However, the number of motor systems 5 to which the regenerative power utilization system 1 is applied is not particularly limited. Furthermore, the number of motors included in each motor system 5 is also not particularly limited. In the illustrated example of FIG. 1A , the number of first motors M11 and the number of second motors M12 are the same (three), but they do not have to be the same. Hereinafter, when there is no need to distinguish between the first motor M11 and the second motor M12, they may be simply referred to as "motor M1."

[0013] Each motor M1 is, for example, a servo motor. Each motor M1 is, for example, a rotary motor, but may also be a linear motor. Each motor M1 includes, for example, a stator wound with three-phase (U-phase, V-phase, and W-phase) windings. Each motor system 5 is configured to drive and control the operation (rotational operation) of the motor M1. As an example, the rated voltage (voltage specification) of the first motor M11 is 48 V, and the rated voltage (voltage specification) of the second motor M12 is 100 V. That is, the voltage specification of the second motor M12 is higher than the voltage specification of the first motor M11. The specifications of the motor M1 itself are not particularly limited. The motor M1 may be a motor that does not require a servo amplifier, may be a brushless motor or a brush motor, and may be an AC motor or a DC motor.

[0014] 1A, the regenerative power utilization system 1 includes a step-up / step-down power conversion circuit 2, a power storage device 3, and a control unit 4. The power conversion circuit 2 is connected between a first bus line B1 for supplying power to a first motor system 51 and a second bus line B2 for supplying power to a second motor system 52. The power conversion circuit 2 has a plurality of switch elements SW0 and performs switching operations for the plurality of switch elements SW0 (two switch elements, a first switch element SW1 and a second switch element SW2, in FIG. 1A).

[0015] The power storage device 3 is connected to the power conversion circuit 2 on the first bus line B1 side or the second bus line B2 side of the power conversion circuit 2. The control unit 4 controls the multiple switch elements SW0 so as to charge the power storage device 3 with regenerative power. In the following embodiment, as an example, the power storage device 3 is connected to the power conversion circuit 2 on the second bus line B2 side. When specific conditions are satisfied, the control unit 4 controls the multiple switch elements SW0 so that the stored power of the power storage device 3 is used as running power for the first motor system 51. As an example, the specific conditions include a condition that the amount of running power generated on the first bus line B1 is equal to or greater than the amount of regenerative power generated and that the amount of regenerative power generated on the second bus line B2 is greater than the amount of running power generated.

[0016] According to the regenerative power utilization system 1 described above, the power storage device 3 is charged with regenerative power generated by the first motor system 51 and the second motor system 52, which have different voltage specifications for the motor M1. Furthermore, the power stored in the power storage device 3 is used as power for driving the first motor system 51. As a result, the regenerative power utilization system 1 has the advantage of being able to improve the utilization of regenerative power.

[0017] A control method according to one aspect relates to the utilization of regenerative power generated in at least two types of motor systems 5. The control method includes a first control step and a second control step. In the first control step, a plurality of switch elements SW0 in the step-up / step-down power conversion circuit 2 are controlled to charge the power storage device 3 with regenerative power. In the second control step, when a specific condition is satisfied, the plurality of switch elements SW0 are controlled so that the stored power in the power storage device 3 is used to power the first motor system 51. This configuration provides a control method that improves the utilization of regenerative power. This control method is used on a computer system (the control unit 4 of the regenerative power utilization system 1). In other words, this control method can also be embodied as a program. A program according to one aspect causes one or more processors to execute the control method.

[0018] (Details) Hereinafter, the entire system (motor management system 100) including the regenerative power utilization system 1 according to this embodiment and its peripheral configuration will be described in detail with reference to FIGS. 1A and 1B.

[0019] Motor management system 100 can be installed in a facility such as a factory. As shown in FIG. 1A , the peripheral configuration of motor management system 100 includes a first configuration group A1 related to first motor system 51 and a second configuration group A2 related to second motor system 52.

[0020] The first component group A1 includes a power source E1 (e.g., a commercial AC power source), a rectifier F1, a first bus line B1, one or more (three in this example) first motors M11 (servo motors), and a power conversion unit G1 (i.e., a total of three in FIG. 1A ) corresponding to each first motor M11. Each power conversion unit G1 is provided, for example, within a servo amplifier. The three first motors M11 and the three power conversion units G1 constitute a first motor system 51. The first motor system 51 also includes a rotation speed detection unit that detects the rotation speed of each first motor M11 and a motor drive device that controls the power conversion unit G1 to drive the first motor M11. In short, the first motor system 51 is configured to drive and control the operation (here, rotational operation) of each first motor M11. The first component group A1 may also include a host controller and a user interface (such as a display monitor and an operating device) for inputting various settings and monitoring operation.

[0021] The second component group A2 includes a power source E2 (e.g., a commercial AC power source), a rectifier F2, a second bus line B2, one or more (three in this example) second motors M12 (servo motors), and a power conversion unit G2 (i.e., a total of three in FIG. 1A ) corresponding to each second motor M12. Each power conversion unit G2 is provided, for example, within a servo amplifier. The three second motors M12 and the three power conversion units G2 constitute a second motor system 52. The second motor system 52 also includes a rotation speed detection unit that detects the rotation speed of each second motor M12 and a motor drive device that controls the power conversion unit G2 to drive the second motor M12. In short, the second motor system 52 is configured to drive and control the operation (here, rotational operation) of each second motor M12. The second component group A2 may also include a host controller and a user interface (display monitor, operation device, etc.) for inputting various settings and monitoring operation. The upper level controller of the first constituent group A1 and the upper level controller of the second constituent group A2 may be realized by a single upper level controller.

[0022] As described above, the multiple motors M1 included in the first constituent group A1 and the second constituent group A2 are rotary motors. However, the multiple motors M1 may also include linear motors. Each motor M1 has an output shaft and rotates the output shaft under the control of a motor drive device. Each motor M1 forms a drive system together with a mechanical mechanism. The mechanical mechanism is not particularly limited, but may be, for example, a ball screw mechanism, a gear mechanism, or a belt mechanism. The mechanical mechanism is connected to the output shaft of the motor M1. The mechanical mechanism is powered by the motor M1. For example, when some of the multiple motors M1 are applied to a conveying device such as a belt conveyor in a facility such as a factory, rotation of the output shaft of the motor M1 rotates the belt via the mechanical mechanism, and multiple products or parts placed on the belt are automatically conveyed in sequence. Furthermore, some of the multiple motors M1 are also applied to a robot arm in a facility such as a factory.

[0023] Each motor M1 is, for example, a three-phase brushless motor and has a stator around which three-phase windings are wound. Specifically, the motor M1 has a stator with U-phase, V-phase, and W-phase windings wound around a stator core, and a rotor with a permanent magnet. The motor M1 also has first to third terminals corresponding to the three-phase input terminals. The rotor rotates when a drive voltage generated by a power conversion unit (G1 or G2) is applied to the first to third terminals under the control of a motor drive device to flow a drive current.

[0024] The voltage specification of the second motor M12 is higher than the voltage specification of the first motor M11. The rated voltage (voltage specification) of the first motor M11 is, for example, 48 V. The rated voltage (voltage specification) of the second motor M12 is, for example, 100 V. The first motor M11 is connected to a 48 V system in the first motor system 51, and the first motor system 51 is connected to a first bus line B1 of DC 48 V. The second motor M12 is connected to a 100 V system in the second motor system 52, and the second motor system 52 is connected to a second bus line B2 of DC 100 V.

[0025] The above-described values ​​for the voltage specifications and their combinations are merely examples. For example, the rated voltage of the first motor M11 may be 48 V, and the rated voltage of the second motor M12 may be 200 V. In this case, the first motor system 51 may be connected to the first bus line B1 with a DC voltage of 48 V, and the second motor system 52 may be connected to the second bus line B2 with a DC voltage of 200 V. Alternatively, the rated voltage of the first motor M11 may be 100 V, and the rated voltage of the second motor M12 may be 200 V. In this case, the first motor system 51 may be connected to the first bus line B1 with a DC voltage of 100 V, and the second motor system 52 may be connected to the second bus line B2 with a DC voltage of 200 V. In particular, the values ​​for the above-described voltage specifications may differ between countries, including Japan, and may be changed as appropriate.

[0026] The rotation speed detector included in each motor in the first component group A1 and the second component group A2 is composed of an encoder or the like, and detects the rotation speed (in other words, the rotation speed) of the corresponding motor M1 based on the rotation position of the motor M1. The rotation speed detector is electrically connected to the motor drive device. The rotation speed detector outputs a detection signal (electrical signal) including the detection value to the motor drive device. The motor drive device controls the operation of the motor M1 to perform a predetermined task (e.g., a conveying task) based on the detection signal from the rotation speed detector and a control signal from a higher-level controller.

[0027] Each of the upper level controllers included in the first configuration group A1 and the second configuration group A2 is configured using, for example, a programmable logic controller or the like, and controls the motor drive device by issuing operation commands, etc. The upper level controller and the motor drive device are communicably connected via a control bus line or the like, and operation commands from the upper level controller are transmitted to the motor drive device, and information from the motor drive device is transmitted to the upper level controller.

[0028] The rectifier F1 in the first component group A1 rectifies AC power supplied from the power source E1 and converts it into DC power, which is then output to the three power conversion units G1 of the first motor system 51 via the first bus line B1. Specifically, the first bus line B1 has a first electrical circuit B11 on the high-potential side and a second electrical circuit B12 on the low-potential side. The high-potential output terminal of the pair of output terminals of the rectifier F1 is electrically connected to the high-potential input terminal of the pair of input terminals of each power conversion unit G1 via the first electrical circuit B11 of the first bus line B1. The low-potential output terminal of the pair of output terminals of the rectifier F1 is electrically connected to the low-potential input terminal of the pair of input terminals of each power conversion unit G1 via the second electrical circuit B12 of the first bus line B1. In short, the first bus line B1 is a bus line configured to supply DC power to the first motor system 51. In addition, the first electrical circuit B11 on the high potential side is also electrically connected to the first input / output terminal T11 of the regenerative power utilization system 1 described later, and the second electrical circuit B12 on the low potential side is also electrically connected to the second input / output terminal T12 of the regenerative power utilization system 1 described later.

[0029] Each power conversion unit G1 includes an inverter unit. The inverter unit receives DC power from a rectifier F1. The inverter unit of each power conversion unit G1 includes multiple semiconductor switching elements 510 (only one is shown in FIG. 1A ) that perform switching operations. Specifically, the inverter unit includes insulated gate bipolar transistors (IGBTs) as the semiconductor switching elements 510. The semiconductor switching elements 510 may also be metal-oxide-semiconductor field-effect transistors (MOSFETs). The multiple semiconductor switching elements 510 in the inverter unit are PWM-controlled by PWM signals output from a processing unit of the motor drive device. As a result, the DC power is converted into three-phase AC power consisting of U, V, and W phases. Each power conversion unit G1 supplies the converted three-phase AC power to a corresponding first motor M11 to drive the first motor M11. The regenerative power generated by each first motor M11 can be sent to the first bus line B1 via the power conversion unit G1 and input to the regenerative power utilization system 1.

[0030] The rectifier F2 in the second component group A2 rectifies AC power supplied from the power source E2 and converts it into DC power, which is then output to the three power conversion units G2 of the second motor system 52 via the second bus line B2. Specifically, the second bus line B2 has a first electrical circuit B21 on the high-potential side and a second electrical circuit B22 on the low-potential side. The high-potential output terminal of the pair of output terminals of the rectifier F2 is electrically connected to the high-potential input terminal of the pair of input terminals of each power conversion unit G2 via the first electrical circuit B21 of the second bus line B2. The low-potential output terminal of the pair of output terminals of the rectifier F2 is electrically connected to the low-potential input terminal of the pair of input terminals of each power conversion unit G2 via the second electrical circuit B22 of the second bus line B2. In short, the second bus line B2 is a bus line configured to supply DC power to the second motor system 52. In addition, the first electrical circuit B21 on the high potential side is also electrically connected to the first input / output terminal T21 of the regenerative power utilization system 1 described later, and the second electrical circuit B22 on the low potential side is also electrically connected to the second input / output terminal T22 of the regenerative power utilization system 1 described later.

[0031] Each power conversion unit G2 includes an inverter unit. The inverter unit receives DC power from the rectifier F2. The inverter unit of each power conversion unit G2 includes multiple semiconductor switching elements 520 (only one is shown in FIG. 1A ) that perform switching operations. Specifically, the inverter unit includes IGBTs as the semiconductor switching elements 520. The semiconductor switching elements 520 may also be MOSFETs. The multiple semiconductor switching elements 520 in the inverter unit are PWM-controlled by PWM signals output from a processing unit of the motor drive device. As a result, the DC power is converted into three-phase AC power consisting of U, V, and W phases. Each power conversion unit G2 supplies the converted three-phase AC power to the corresponding second motor M12 to drive the second motor M12. Regenerative power generated by each second motor M12 is transmitted to the second bus line B2 via the power conversion unit G2 and input to the regenerative power utilization system 1.

[0032] The regenerative power utilization system 1 is configured to utilize regenerative power generated by at least two types of motor systems 5. As described above, in the present embodiment, as an example, the regenerative power utilization system 1 is configured to utilize regenerative power generated by the first motor system 51 and the second motor system 52.

[0033] The regenerative power utilization system 1 includes a step-up / step-down power conversion circuit 2, a power storage device 3, and a control unit 4. The regenerative power utilization system 1 further includes a pair of input / output terminals (first input / output terminal T11 and second input / output terminal T12) connected to the first bus line B1 side, and a pair of input / output terminals (first input / output terminal T21 and second input / output terminal T22) connected to the second bus line B2 side. The regenerative power utilization system 1 further includes a first measurement unit H1 and a second measurement unit H2.

[0034] The regenerative power utilization system 1 is assumed to be realized as a single device in which the power conversion circuit 2, the power storage device 3, the control unit 4, the first measurement unit H1, and the second measurement unit H2 are housed in a single housing. However, the regenerative power utilization system 1 may be realized, for example, by a plurality of devices that can be electrically connected to each other, and the power conversion circuit 2, the power storage device 3, the control unit 4, the first measurement unit H1, and the second measurement unit H2 may be housed in a distributed manner in a plurality of housings of the plurality of devices.

[0035] The power conversion circuit 2 is configured as a bidirectional DC-DC conversion circuit. The power conversion circuit 2 is connected between a first bus line B1 and a second bus line B2. The power conversion circuit 2 includes, for example, a plurality of switch elements SW0 (here, two semiconductor switching elements: a first switch element SW1 and a second switch element SW2) and an inductor L1. Hereinafter, when the two switch elements SW0 need to be distinguished from each other for the sake of explanation, they will be referred to as the first switch element SW1 and the second switch element SW2, and when they are not to be distinguished from each other for the sake of explanation, they may be simply referred to as the switch element SW0.

[0036] The inductor L1 has a first end and a second end. The first end of the inductor L1 is electrically connected to a first input / output terminal T11, which is connected to a first electrical path B11 on the high-potential side of the first bus line B1. The second end of the inductor L1 is electrically connected to a connection point 21.

[0037] Each of the first switch element SW1 and the second switch element SW2 has a control terminal, a first main terminal, and a second main terminal. Each switch element SW0 is, for example, an IGBT. Therefore, the control terminal, the first main terminal, and the second main terminal of each switch element SW0 are a gate terminal, a collector terminal, and an emitter terminal, respectively. However, each switch element SW0 is not limited to an IGBT, and may be a MOSFET, a bipolar transistor, a GaN-based transistor, or the like.

[0038] The control terminal of each switch element SW0 is electrically connected to the control unit 4. The first main terminal of the first switch element SW1 is electrically connected to a high-potential side terminal of the power storage device 3. The second main terminal of the first switch element SW1 is electrically connected to a first main terminal of the second switch element SW2 via a connection point 21. The second main terminal of the second switch element SW2 is electrically connected to a connection point 22. The connection point 22 is electrically connected to a second input / output terminal T12 that is connected to a second electrical path B12 on the low-potential side of the first bus line B1. The connection point 22 is also electrically connected to a low-potential side terminal of the power storage device 3.

[0039] The power conversion circuit 2 performs switching operations for two switch elements SW0. That is, the first switch element SW1 and the second switch element SW2 are switched on and off under the control of the control unit 4. Simply put, the power conversion circuit 2 is a 48V / 100V conversion circuit.

[0040] The power storage device 3 has a plurality of electrolytic capacitors 30 (three in FIG. 1A as an example). In the present embodiment, as an example, the power storage device 3 is connected to the power conversion circuit 2 on the second bus line B2 side of the power conversion circuit 2. The three electrolytic capacitors 30 are connected in parallel with each other. Each of the three electrolytic capacitors 30 has a first end and a second end. It is assumed that the power storage device 3 has a plurality of electrolytic capacitors 30 with a withstand voltage of, for example, 200V.

[0041] The first ends of the three electrolytic capacitors 30 are electrically connected to connection points 31, 32, and 33 (on the high potential side), respectively. The connection point 31 is electrically connected to a first main terminal of the first switch element SW1. The connection point 33 is electrically connected to a first input / output terminal T21, which is connected to a first electrical path B21 on the high potential side of the second bus line B2.

[0042] The second ends of the three electrolytic capacitors 30 are electrically connected to connection points 34, 35, and 36 (on the low potential side), respectively. Note that the connection point 34 is electrically connected to the connection point 22. The connection point 36 is electrically connected to a second input / output terminal T22 that is connected to a second electrical path B22 on the low potential side of the second bus line B2.

[0043] The type of the power storage device 3 in the present disclosure is not particularly limited. The power storage device 3 may be realized by a film capacitor, an electric double layer capacitor (capacitor), a lithium ion capacitor, or the like. However, a power storage device 3 that satisfies the withstand voltage conditions according to the voltage specifications on the second bus line B2 side is preferable. In this respect, it is more preferable to realize the power storage device 3 by using an electrolytic capacitor 30, which is unlikely to be large, has a high withstand voltage, and is unlikely to be complex to control, as in this embodiment. Conversely, the power storage device 3 may be connected to the power conversion circuit 2 on the first bus line B1 side of the power conversion circuit 2, in which case it may be realized by a device with a relatively low withstand voltage.

[0044] The executing entity of the control unit 4 includes a computer system having one or more processors and memory. At least some of the functions of the control unit 4 are realized by the processor of the computer system executing a program recorded in the memory of the computer system. The program may be recorded in the memory, or may be provided via a telecommunications line such as the Internet, or may be provided by being recorded on a non-transitory recording medium such as a memory card.

[0045] The control unit 4 controls the first switch element SW1 and the second switch element SW2 in the power conversion circuit 2 so that the power storage device 3 is charged with regenerative power generated in the first motor system 51 and the second motor system 52. Furthermore, when a specific condition is satisfied, the control unit 4 controls the first switch element SW1 and the second switch element SW2 so that the stored power in the power storage device 3 is used as power for driving the first motor system 51. Note that in this embodiment, it is assumed that the stored power in the power storage device 3 is also used as power for driving the second motor system 52, and can be used as power for driving the second motor system 52 when a certain condition is satisfied.

[0046] The control unit 4 generates control signals S1 and S2 that control the on / off states of the first switch element SW1 and the second switch element SW2, respectively, and outputs them to the control terminals (gate terminals) of the first switch element SW1 and the second switch element SW2. Each of the control signals S1 and S2 is, for example, a PWM signal whose potential level changes between a first potential level (hereinafter also referred to as a low level) and a second potential level (hereinafter also referred to as a high level) that is higher than the first potential level. The first switch element SW1 is in an on state when the control signal S1 is at a high level, and in an off state when the control signal S1 is at a low level. Similarly, the second switch element SW2 is in an on state when the control signal S2 is at a high level, and in an off state when the control signal S2 is at a low level.

[0047] The control unit 4 adjusts the duty of each of the control signals S1 and S2 to perform switching control on the first switch element SW1 and the second switch element SW2 so that the voltage output from the power conversion circuit 2 approaches a target value.

[0048] In this embodiment, the control unit 4 controls the first switch element SW1 and the second switch element SW2 so as to boost the regenerative power generated in the first motor system 51 and charge the power storage device 3 (charge control: first control step). The control unit 4 also controls the first switch element SW1 and the second switch element SW2 so as to lower the voltage of the power stored in the power storage device 3 and use it as power for driving the first motor system 51 (discharge control: second control step).

[0049] 1B, the control unit 4 has an acquisition unit 40, a determination unit 41, and a decision unit 42. In other words, the control unit 4 has the function of the acquisition unit 40, the function of the determination unit 41, and the function of the decision unit 42.

[0050] The acquiring unit 40 is configured to acquire information including measurement values ​​as electrical signals from the first measuring unit H1 and the second measuring unit H2. That is, the first measuring unit H1 and the second measuring unit H2 are electrically connected to the control unit 4. The first measuring unit H1 monitors (measures) the power status on the first bus line B1 side and outputs the measurement result (first measurement value) to the control unit 4. The second measuring unit H2 monitors (measures) the power status on the second bus line B2 side and outputs the measurement result (second measurement value) to the control unit 4. In this embodiment, as an example, the measurement values ​​(first measurement value and second measurement value) are voltage values. The acquiring unit 40 acquires the first measurement value and the second measurement value.

[0051] For example, the first measurement unit H1 measures the voltage V between the first input / output terminal T11 and the second input / output terminal T12 on the first bus line B1 side. Ｌ The second measuring unit H2 includes a voltmeter arranged to measure (detect) the voltage V between the first input / output terminal T21 and the second input / output terminal T22 on the second bus line B2 side, and outputs the measured voltage value as a first measurement value to the control unit 4. Ｈ The voltage measurement circuit 10 includes a voltmeter arranged to measure (detect) the voltage (see FIG. 1A), and outputs the measured voltage value to the control unit 4 as a second measurement value.

[0052] The measured value (here, the voltage value) may be an instantaneous value, or may be an average value, maximum value, minimum value, median value, or representative value of sampled data within a predetermined period. The measured value is not limited to a voltage value. The measured value may be a value related to at least one of a current value, a voltage value, a current rise rate, and a voltage rise rate.

[0053] The determination unit 41 is configured to determine the magnitude of the amount of generated traction power and the amount of generated regenerative power on each of the first bus line B1 and the second bus line B2. That is, the determination unit 41 determines the magnitude of the amount of generated traction power and the amount of generated regenerative power on the first bus line B1 side, and further determines the magnitude of the amount of generated traction power and the amount of generated regenerative power on the second bus line B2 side. In the present embodiment, as an example, the determination unit 41 compares a measured value (here, a voltage value) with a reference value to determine which of the amount of generated traction power and the amount of generated regenerative power is dominant in the current power situation on each bus line. The determination unit 42 determines one control mode from among multiple control modes based on the determination result by the determination unit 41. The control unit 4 controls the multiple switch elements SW0 in the control mode determined by the determination unit 42. The multiple control modes include at least a step-up control mode and a step-down control mode. In this manner, by determining the control mode based on the judgment result of the judgment unit 41, more appropriate control of the power conversion circuit 2 can be achieved according to the state of the running power and regenerative power on each of the first bus line B1 side and the second bus line B2 side.

[0054] Hereinafter, the voltage step-up control mode may be referred to as a charge mode, and the voltage step-down control mode may be referred to as a discharge mode. In this embodiment, the control modes include, for example, a standby mode in addition to the voltage step-up control mode (charge mode) and the voltage step-down control mode (discharge mode), as will be described in detail later.

[0055] [Charging Mode] Here, the charging mode in the present disclosure will be described. First, in this embodiment, when regenerative power is generated on the second bus line B2 side, the power storage device 3 is connected on the second bus line B2 side so that charging to the power storage device 3 occurs naturally without control intervention by the control unit 4. Therefore, the charging mode is a mode in which the voltage of the regenerative power generated on the first bus line B1 side is boosted and the power storage device 3 is charged with the boosted power. In the charging mode, the control unit 4 controls the multiple switch elements SW0 to boost the voltage of the regenerative power generated on the first bus line B1 side. Specifically, the control unit 4 controls the bus voltage on the second bus line B2 side, i.e., the voltage V between the first input / output terminal T21 and the second input / output terminal T22. Ｈ The controller 4 sets a target voltage value higher than the current voltage value (second measurement value) of the second bus line B2. By setting such a target value, the voltage on the second bus line B2 side is increased so that current flows in the opposite direction to the direction indicated by "Iout" in FIG. 1A. The controller 4 generates a duty control signal corresponding to the target value (e.g., the difference between the target value and the most recent measurement value) and outputs it to the control terminal of the second switch element SW2 to control the on / off switching of the second switch element SW2. In the charging mode, the controller 4 either maintains the first switch element SW1 in the off state, or controls the second switch element SW2 so that it is in the off state when the second switch element SW2 is on and in the on state when the second switch element SW2 is off. In short, in the charging mode, the controller 4 sets a target voltage value on the second bus line B2 side and performs constant voltage control.

[0056] [Discharge Mode] Here, the discharge mode in the present disclosure will be described. First, in this embodiment, as described above, it is assumed that the stored power of the power storage device 3 is also used as power for propelling the second motor system 52. Here, the discharge mode will be described as a mode in which the voltage of the power discharged from the power storage device 3 is lowered and the power storage device 3 is discharged so that the lowered power can be used as power for propelling on the first bus line B1 side. In the discharge mode, the control unit 4 controls the multiple switch elements SW0 to lower the voltage of the power discharged from the power storage device 3. Specifically, the control unit 4 controls the bus voltage on the first bus line B1 side, i.e., the voltage V between the first input / output terminal T11 and the second input / output terminal T12. Ｌ The control unit 4 sets a target voltage value higher than the current voltage value (first measurement value) of the first bus line B1. By setting such a target value, the voltage on the first bus line B1 side is increased so that current flows in the direction indicated by "Iout" in FIG. 1A. The control unit 4 generates a duty control signal corresponding to the target value (e.g., the difference between the target value and the most recent measurement value) and outputs it to the control terminal of the first switch element SW1 to perform on / off switching control of the first switch element SW1. In the discharge mode, the control unit 4 either maintains the second switch element SW2 in the off state, or controls the second switch element SW2 to be in the off state when the first switch element SW1 is on and to be in the on state when the first switch element SW1 is off. In short, in the discharge mode, the control unit 4 sets a target voltage value on the first bus line B1 side and performs constant voltage control.

[0057] In this embodiment, the control unit 4 performs switching control by adjusting the duty on ratio to less than 1 as needed, but in order to shorten the charging and discharging time of the energy storage device 3 as much as possible, the duty may be fixed at a preset value in each of the charging mode and discharging mode to perform switching control.

[0058] As described above, the control unit 4 sets a target voltage value higher than the current voltage value for either the first bus line B1 or the second bus line B2, which bus line carries current from the regenerative power utilization system 1, in accordance with the determination result by the determination unit 42. Then, the control unit 4 adjusts the duty cycles related to the switching control of the multiple switch elements SW0.

[0059] For example, in the first motor system 51, if the power conversion unit G1 supplies power to a first motor M11 at a given time to drive a load, the motor system may be in a power running state. However, if another first motor M11 is decelerating at the same time, the motor system may be in a regenerative state in which the rotational energy of the first motor M11 flows into the power conversion unit G1. Therefore, the determination unit 41 uses measured values ​​to determine which of the generated power and the generated regenerative power is dominant in the current power situation of the first motor system 51 as a whole. Similarly, for the second motor system 52, the determination unit 41 uses measured values ​​to determine which of the generated power and the generated regenerative power is dominant in the current power situation of the second motor system 52 as a whole.

[0060] The determination unit 41 compares the measured values ​​for each of the first bus line B1 and the second bus line B2 with a predetermined reference value (standard voltage value). Information about the reference value is pre-stored in, for example, the memory of the control unit 4 or a storage unit (an electrically rewritable non-volatile semiconductor memory such as a flash memory) provided separately from the memory. The reference value (first reference value) compared with the measured value for the first bus line B1 is different from the reference value (second reference value) compared with the measured value for the second bus line B2. The reference value is preferably set as a reference range with a certain width that includes an allowable error.

[0061] The determination unit 41 determines that the state is a regeneration-dominant state in which the amount of regenerative power generated is greater than the amount of power-running power generated when the measured values ​​for each of the first bus line B1 and the second bus line B2 are greater than a reference value.The determination unit 41 determines that the state is a power-running-dominant state in which the amount of regenerative power generated is smaller than the amount of power-running power generated when the measured values ​​for each of the first bus line B1 and the second bus line B2 are equal to or less than a reference value.

[0062] As an example, it is assumed that the determination is made based on the sign of the difference between the measured value and the reference value. For example, the determination unit 41 determines that the state is in a powering-dominant state if the sign of the difference between the measured value and the reference value is negative (-) or zero (0). If the measured value is within the above-mentioned reference range including the allowable error, the difference is considered to be zero (0). Furthermore, the determination unit 41 determines that the state is in a regeneration-dominant state if the sign of the difference between the measured value and the reference value is positive (+).

[0063] Next, the control modes that the control unit 4 can select depending on whether the first bus line B1 and the second bus line B2 are in a regeneration-dominant state or a power-running-dominant state will be described for situations 1 to 3.

[0064] [Situation 1: One bus line is in a regeneration-dominant state, and the other bus line is in a powering-dominant state] Assume that the determination result by the determination unit 41 indicates that one of the first bus line B1 and the second bus line B2 is in a regeneration-dominant state, and the other bus line is in a powering-dominant state. In this case, the control unit 4 controls the multiple switch elements SW0 to increase the voltage on the other bus line so that current flows from the power storage device 3 to the other bus line that is in a powering-dominant state.

[0065] Specifically, if the first bus line B1 is in a regeneration-dominant state and the second bus line B2 is in a powering-dominant state, the decision unit 42 selects (determines) the charge mode (boost control mode) as the control mode. In the charge mode, the control unit 4 performs on / off switching control of the second switch element SW2 and controls the first switch element SW1 to maintain the off state, thereby boosting the regenerative power from the first bus line B1 side and charging the power storage device 3 with the boosted power. At this time, the control unit 4, as described above, controls the voltage V between the first input / output terminal T21 and the second input / output terminal T22. Ｈ The control unit 4 sets the target voltage to a voltage value higher than the current voltage value (second measured value) of the power storage device 3. By setting such a target voltage, the control unit 4 increases the voltage on the second bus line B2 side so that current flows from the power storage device 3 to the second bus line B2 side, which is in a powering dominant state.

[0066] On the other hand, if the second bus line B2 is in a regeneration-dominant state and the first bus line B1 is in a powering-dominant state, the determination unit 42 selects (determines) the discharge mode (step-down control mode) as the control mode. In the discharge mode, the control unit 4 performs on / off switching control of the first switch element SW1 and controls the second switch element SW2 to maintain the off state, thereby utilizing the power discharged from the power storage device 3 and stepped down in voltage as power for the first motor system 51. At this time, the control unit 4, as described above, determines the voltage V between the first input / output terminal T11 and the second input / output terminal T12. Ｌ The control unit 4 sets the target voltage to a voltage value higher than the current voltage value (first measured value) of the power storage device 3. By setting such a target voltage, the control unit 4 increases the voltage on the first bus line B1 side so that current flows from the power storage device 3 to the first bus line B1 side, which is in a powering dominant state.

[0067] In other words, "the second bus line B2 is in a regeneration-dominant state and the first bus line B1 is in a power-running-dominant state" corresponds to the above-mentioned "specific condition."

[0068] When the first bus line B1 and the second bus line B2 are in a power-operating dominant state, the power supplied from each power source (E1 or E2) is basically utilized. When the first bus line B1 is in a power-operating dominant state, the stored power of the power storage device can be utilized to reduce the power supplied from the power source E1 as much as possible.

[0069] [Situation 2: Both Bus Lines are in a Regeneration-Dominant State] Assume that the determination result by the determination unit 41 indicates that both the first bus line B1 and the second bus line B2 are in a regeneration-dominant state. In this case, the control unit 4 controls the multiple switch elements SW0 to increase the voltage on the second bus line B2 side so that current flows from the power storage device 3 to the second bus line B2 side.

[0070] That is, in situation 2, the control unit 4 basically performs control similar to that in situation 1 above, where "the first bus line B1 is in a regeneration-dominant state and the second bus line B2 is in a powering-dominant state." That is, in situation 2, the decision unit 42 selects (determines) the charge mode (boost control mode) as the control mode. In the charge mode, the control unit 4 performs on-off switching control of the second switch element SW2 and controls the first switch element SW1 to maintain the off state, thereby boosting the regenerative power from the first bus line B1 side and charging the power storage device 3 with the boosted power. Note that the regenerative power from the second bus line B2 side can be stored in the power storage device 3 as long as it is within the allowable range of the power storage device 3.

[0071] However, when both the first bus line B1 and the second bus line B2 are in the regeneration dominant state, the control unit 4 may further compare the voltage increase amounts between the first bus line B1 and the second bus line B2 and determine the control mode based on the comparison result. For example, if the increase amount of the current voltage value of the first bus line B1 relative to the first reference value is equal to or greater than the increase amount of the current voltage value of the second bus line B2 relative to the second reference value, the determination unit 42 may determine the charge mode as the control mode. The comparison is not limited to the increase amount of the voltage value, and may also be the rate of increase of the voltage over a specified period, etc.

[0072] Conversely, if the voltage increase amount on the second bus line B2 is greater than the voltage increase amount on the first bus line B1, the determination unit 42 may determine the standby mode as the control mode. In the standby mode, the control unit 4 controls both the first switch element SW1 and the second switch element SW2 to maintain the off state (shutoff control). In this case, the regenerative power on the first bus line B1 side may be consumed (wasted) by resistors or the like in the first component group A1. In this case, the regenerative power on the second bus line B2 side may also be stored in the power storage device 3 as long as it is within the allowable range of the power storage device 3.

[0073] [Situation 3: Both Bus Lines are in a Powering Dominant State] Assume that the determination result by the determination unit 41 indicates that both the first bus line B1 and the second bus line B2 are in a powering dominant state. In this case, the control unit 4 stops the switching operation so that no current flows from the power storage device 3 to both the first bus line B1 and the second bus line B2.

[0074] That is, in situation 3, the determination unit 42 basically determines the standby mode as the control mode. In the standby mode, the control unit 4 controls both the first switch element SW1 and the second switch element SW2 to maintain the off state (shutoff control). In this case, the first bus line B1 side and the second bus line B2 side use power supplied from the power sources E1 and E2, respectively.

[0075] However, when both the first bus line B1 and the second bus line B2 are in a powering-dominant state, the control unit 4 may further compare the voltage drop amounts between the first bus line B1 and the second bus line B2 and determine the control mode based on the comparison result. For example, if the drop amount of the current voltage value of the first bus line B1 (relative to a first reference value) is equal to or greater than the drop amount of the current voltage value of the second bus line B2 (relative to a second reference value), the determination unit 42 may determine the discharge mode as the control mode. In this case, the first bus line B1 uses power supplied from the power source E1 and the power stored in the power storage device 3, and the second bus line B2 uses power supplied from the power source E2. In other words, "both the first bus line B1 and the second bus line B2 are in a powering-dominant state, and the voltage drop amount of the first bus line B1 is equal to or greater than the voltage drop amount of the second bus line B2" corresponds to the above-mentioned "specific condition." The comparison is not limited to the amount of voltage decrease, but may be the rate of voltage decrease over a specified period, or the like.

[0076] Conversely, if the voltage drop on the second bus line B2 is greater than the voltage drop on the first bus line B1, the determination unit 42 may determine the standby mode as the control mode. In this case, the first bus line B1 side and the second bus line B2 side use power supplied from the power sources E1 and E2, respectively.

[0077] (Operation of Regenerative Power Utilization System: Mode Determination) A series of operational flows related to determining the control mode in the regenerative power utilization system 1 will be described below with reference to the flowchart in Fig. 2. The operational flow described below is merely an example, and the order of processing may be changed as appropriate, and processing may be added or omitted as appropriate.

[0078] The regenerative power utilization system 1 (controller 4) monitors the first measurement value and the second measurement value from the first measurement unit H1 and the second measurement unit H2 (ST1: monitoring measurement values).

[0079] The control unit 4 (determination unit 41) determines the sign of the difference value of the first measurement value with respect to the first bus line B1 side relative to the first reference value (ST2: first bus side difference value≦0). If the sign of the difference value is negative or the difference value is 0 (zero) (ST2: Yes), the determination unit 41 determines that the first bus line B1 side is in a powering dominant state (ST3: first bus side: powering dominant).

[0080] Following step ST3, the determination unit 41 determines the sign of the difference between the second measurement value and the second reference value for the second bus line B2 (ST5: second bus side difference value≦0). If the sign of the difference value is negative or the difference value is 0 (zero) (ST5: Yes), the determination unit 41 determines that the second bus line B2 is in a powering dominant state (ST7: second bus side: powering dominant). The control unit 4 (determination unit 42) determines the standby mode as the control mode based on the determination results of steps ST3 and ST7 (ST11).

[0081] On the other hand, if the sign of the difference value is positive in step ST5 (ST5: No), the determination unit 41 determines that the second bus line B2 side is in a regeneration-dominant state (ST8: second bus side: regeneration-dominant).The determination unit 42 determines the discharge mode as the control mode based on the determination results of steps ST3 and ST8 (ST12).

[0082] Returning to step ST2, if the sign of the difference value of the first measurement value relative to the first reference value is positive (ST2: No), the judgment unit 41 judges that the first bus line B1 side is in a regeneration-dominant state (ST4: First BUS side: Regeneration-dominant).

[0083] Following step ST4, the determination unit 41 determines the sign of the difference between the second measurement value and the second reference value for the second bus line B2 (ST6: second bus side difference value≦0). If the sign of the difference value is negative or the difference value is 0 (zero) (ST6: Yes), the determination unit 41 determines that the second bus line B2 is in a powering dominant state (ST9: second bus side: powering dominant). Based on the determination results of steps ST4 and ST9, the determination unit 42 determines the charging mode as the control mode (ST13).

[0084] On the other hand, if the sign of the difference value is positive in step ST6 (ST6: No), the judgment unit 41 determines that the second bus line B2 side is in a regeneration-dominant state (ST10: second bus side: regeneration-dominant). The decision unit 42 determines the charge mode as the control mode based on the judgment results of steps ST4 and ST10 (ST14). However, if the charge mode is selected based on this judgment result, surplus power may be generated. Therefore, it is preferable to provide a resistor 62 (see FIG. 5: shunt resistor) on the second bus line B2 side to consume the surplus power, as described in Modification 1 below. This is because the second bus line B2 side has a higher voltage than the first bus line B1, allowing for a smaller current value for the same power, and therefore the current rating of the resistor 62 (shunt resistor) can be lowered.

[0085] The control unit 4 controls the switch element SW0 in accordance with the determined control mode (one of ST11 to ST14) (ST15), and returns to step ST1, for example.

[0086] (Operation of Regenerative Power Utilization System: Operation in Charging Mode) A series of operations in the charging mode of the regenerative power utilization system 1 will be described below with reference to the flowchart in Fig. 3. The operation flow described below is merely an example, and the order of processes may be changed as appropriate, and processes may be added or omitted as appropriate.

[0087] When control in the charging mode is started, the regenerative power utilization system 1 (the acquisition unit 40 of the control unit 4) first acquires the voltage V between the first input / output terminal T21 and the second input / output terminal T22 on the second bus line B2 side from the second measurement unit H2. Ｈ (ST21: voltage V Ｈ detection).

[0088] The control unit 4 detects the voltage V Ｈ A voltage value higher than the voltage value (second measured value) is set as the target value (ST22: setting of target value).

[0089] Then, the control unit 4 sets (or changes) the duty in accordance with the difference between the target value and the most recent second measurement value (target value difference), and performs on / off switching control of the second switch element SW2 (ST23: change duty in accordance with target value difference).In the charging mode, the control unit 4 controls the first switch element SW1 to maintain the off state.

[0090] Next, the control unit 4 determines the voltage V Ｈ and detecting a voltage V (between the first input / output terminal T11 and the second input / output terminal T12 on the first bus line B1 side). Ｌ That is, the acquisition unit 40 of the control unit 4 detects the voltage V Ｈ and further obtains the voltage V from the first measurement unit H1. Ｌ Get.

[0091] The control unit 4 controls the voltage V Ｈ The first condition is "= target value" and the second condition is "voltage V ＬIt is then determined whether or not the first condition "initial voltage value on the first bus line B1 side (first BUS side)" is satisfied (ST25). The "initial voltage value on the first bus line B1 side (first BUS side)" here is, for example, a first reference value (standard voltage value) used to determine whether the first bus line B1 is in a powering-dominant state or a regeneration-dominant state. Alternatively, it may be a preset value separate from the first reference value.

[0092] If the control unit 4 determines that the first condition or the second condition is satisfied (ST25: Yes), it terminates control in the charging mode. However, if the control unit 4 determines that neither the first condition nor the second condition is satisfied (ST25: No), it returns to step ST23. Then, the control unit 4 changes the duty in accordance with the difference (target value difference) between the target value and the most recent second measurement value (acquired in step ST24) and performs on / off switching control of the second switch element SW2. In other words, in this embodiment, as an example, the control unit 4 continues control in the charging mode unless the first condition or the second condition is satisfied.

[0093] (Operation of Regenerative Power Utilization System: Operation in Discharge Mode) A series of operations in the discharge mode of the regenerative power utilization system 1 will be described below with reference to the flowchart in Fig. 4. The operation flow described below is merely an example, and the order of processes may be changed as appropriate, and processes may be added or omitted as appropriate.

[0094] When the regenerative power utilization system 1 (the acquisition unit 40 of the control unit 4) starts to execute control in the discharge mode, first, the first measurement unit H1 measures the voltage V between the first input / output terminal T11 and the second input / output terminal T12 on the first bus line B1 side. Ｌ (ST31: voltage V Ｌ detection).

[0095] The control unit 4 detects the voltage V Ｌ A voltage value higher than the voltage value (first measured value) is set as the target value (ST32: setting of target value).

[0096] Then, the control unit 4 sets (or changes) the duty in accordance with the difference between the target value and the most recent first measurement value (target value difference), and performs on / off switching control of the first switch element SW1 (ST33: change duty in accordance with target value difference).In the discharge mode, the control unit 4 controls the second switch element SW2 to maintain the off state.

[0097] Next, the control unit 4 detects the voltage V (between the first input / output terminal T21 and the second input / output terminal T22 on the second bus line B2 side) Ｈ and voltage V Ｌ That is, the acquisition unit 40 of the control unit 4 detects the voltage V Ｌ and further obtains the voltage V from the second measurement unit H2. Ｈ Get.

[0098] The control unit 4 controls the voltage V Ｌ = target value” and the third condition “Voltage V Ｈ It is then determined whether or not the first condition, "initial voltage value on the second bus line B2 side (second BUS side)" is satisfied (ST35). The "initial voltage value on the second bus line B2 side (second BUS side)" here is, for example, a second reference value (standard voltage value) used to determine whether the second bus line B2 is in a powering-dominant state or a regeneration-dominant state. Alternatively, it may be a preset value separate from the second reference value.

[0099] If the control unit 4 determines that the third condition or the fourth condition is satisfied (ST35: Yes), it terminates the control in the discharge mode. However, if the control unit 4 determines that neither the third condition nor the fourth condition is satisfied (ST35: No), it returns to step ST33. Then, the control unit 4 changes the duty according to the difference (target value difference) between the target value and the most recent first measurement value (acquired in step ST34) and performs on / off switching control of the first switch element SW1. In other words, in this embodiment, as an example, the control unit 4 continues the control in the discharge mode unless the third condition or the fourth condition is satisfied.

[0100] [Advantages] As described above, according to the regenerative power utilization system 1 of this embodiment, the regenerative power generated by the first motor system 51 and the second motor system 52, which have different voltage specifications for the motor M1, is stored in the power storage device 3. Furthermore, the stored power in the power storage device 3 is used as power for the first motor system 51. Therefore, for example, the regenerative power generated by the first motor M11 is less likely to be consumed (discarded) within the first motor system 51, and the power for power is efficiently used in the regenerative power utilization system 1. As a result, the regenerative power utilization system 1 has the advantage of being able to improve the utilization of regenerative power.

[0101] Furthermore, in this embodiment, the power storage device 3 is connected closer to the second bus line B2 than the power conversion circuit 2. Therefore, for example, by using a high-voltage power storage device 3, regenerative power generated by the second motor system 52 with high voltage specifications can be more efficiently stored in the power storage device 3 without stepping down the voltage. In particular, in this embodiment, because the power storage device 3 is located on the second bus line B2 side, for example, when the second bus line B2 is in a power running dominant state, the stored power in the power storage device 3 can be used as power running power for the second motor system 52 (as needed in any control mode).

[0102] In this embodiment, the regenerative power utilization system 1 determines whether the first bus line B1 and the second bus line B2 are in a state where powering or regeneration is dominant, and determines the control mode based on a combination of the determination results, thereby achieving more appropriate control of the power conversion circuit 2.

[0103] (Modification 1) A regenerative power utilization system 1 according to this modification (modification 1) will be described in detail below with reference to Fig. 5. Hereinafter, with regard to the components of the regenerative power utilization system 1 according to modification 1, components that are substantially the same as those of the regenerative power utilization system 1 of the above embodiment will be assigned the same reference numerals and their description may be omitted as appropriate. Note that Fig. 5 only shows the configuration of the regenerative power utilization system 1 according to modification 1, and the configuration of the first motor system 51 and the second motor system 52 is not shown.

[0104] As shown in FIG. 5, the regenerative power utilization system 1 according to the first modification differs from the regenerative power utilization system 1 according to the above embodiment in that it further includes a capacitor C1 and a power consumption unit 6.

[0105] The capacitor C1 is disposed closer to the first bus line B1 than the power conversion circuit 2. The capacitor C1 has a first end and a second end. The first end of the capacitor C1 is electrically connected to the first electrical path B11 of the first bus line B1, and the second end of the capacitor C1 is electrically connected to the second electrical path B12 of the first bus line B1. Specifically, the first end of the capacitor C1 is electrically connected to a connection point P1 between the first input / output terminal T11 and the first end of the inductor L1. The second end of the capacitor C1 is electrically connected to a connection point P2 between the second input / output terminal T12 and the connection point 22. It is assumed that the capacitor C1 is, for example, a low-voltage electrolytic capacitor.

[0106] In this way, by arranging the capacitor C1 closer to the first bus line B1 than the power conversion circuit 2, when a relatively large current is input to the regenerative power utilization system 1 from the first bus line B1, the current is smoothed by the capacitor C1. Therefore, for example, when regenerative power suddenly increases on the first bus line B1, the rate of voltage increase in the transient response of the regenerative power utilization system 1 can be suppressed. In other words, the control unit 4, which determines whether powering or regeneration is dominant on the first bus line B1 based on the first measurement value measured by the first measurement unit H1 and determines the control mode, may not be able to immediately follow the sudden increase in regenerative power. However, by providing the capacitor C1, the sudden increase in regenerative power can be mitigated. Note that in the first modification, the first measurement unit H1 measures the voltage V on the opposite side of the power conversion circuit 2 from the capacitor C1, specifically, at both ends on the motor side of the connection points P1 and P2. Ｌ are positioned to measure the

[0107] The power consumption unit 6 is arranged closer to the second bus line B2 than the power conversion circuit 2. The power consumption unit 6 has a specific switch element 61 and a resistor 62. The specific switch element 61 is controlled to be switched on and off by the control unit 4. The resistor 62 is connected in series with the specific switch element 61.

[0108] Specifically, the specific switch element 61 is, for example, an IGBT. Therefore, the control terminal, the first main terminal, and the second main terminal of the specific switch element 61 are a gate terminal, a collector terminal, and an emitter terminal, respectively. However, the specific switch element 61 is not limited to an IGBT, and may be a MOSFET, a bipolar transistor, a GaN-based transistor, or the like. The resistor 62 functions as, for example, a shunt resistor for shunting a portion of the current flowing from the second bus line B2 toward the power storage device 3. The resistor 62 has a first end and a second end.

[0109] A first main terminal of the specific switch element 61 is electrically connected to a connection point P3 between the connection point 33 and the first input / output terminal T21. A second main terminal of the specific switch element 61 is electrically connected to a first end of the resistor 62. A second end of the resistor 62 is electrically connected to a connection point P4 between the connection point 36 and the second input / output terminal T22. The specific switch element 61 and the resistor 62 may be connected inversely. That is, the first end of the resistor 62 may be connected to the connection point P3, the second end of the resistor 62 may be connected to the first main terminal of the specific switch element 61, and the second main terminal of the specific switch element 61 may be connected to the connection point P4. A control terminal of the specific switch element 61 is electrically connected to the control unit 4.

[0110] The control unit 4 controls a specific switch element 61 to be turned on so that surplus power (of the regenerative power) generated on the second bus line B2 side is consumed by the resistor 62. The control content will be specifically described below.

[0111] In the first modification, the control unit 4 is configured to execute surplus power processing when a specified condition is satisfied while the second bus line B2 side is in a regeneration-dominant state. The surplus power processing is executed when the specified condition is satisfied regardless of whether control is being performed in the charge mode, discharge mode, or standby mode described in the above embodiment. For example, when the second bus line B2 side is in a regeneration-dominant state, there is a possibility that regenerated power will be generated to the extent that it exceeds the allowable charge capacity of the power storage device 3 (the current capacity that can be stored in the power storage device). The specified condition may be, for example, that the amount of regenerated power generated on the second bus line B2 side exceeds a certain amount set based on the allowable charge capacity of the power storage device 3. The control unit 4 may start executing surplus power processing when the amount of regenerated power generated on the second bus line B2 side exceeds the certain amount (when the specified condition is satisfied).

[0112] While surplus power processing is not being performed, the specific switch element 61 is maintained in the OFF state. During surplus power processing, the control unit 4 generates a control signal U1 (see FIG. 5) for controlling the specific switch element 61 to turn ON, and outputs the control signal U1 to the control terminal of the specific switch element 61. As a result, during surplus power processing, the specific switch element 61 is maintained in the ON state, and surplus power is consumed by the resistor 62. If the specified condition changes to no longer being satisfied during surplus power processing, the control unit 4 controls the specific switch element 61 to the OFF state, and ends the execution of surplus power processing.

[0113] An example of the application of surplus power processing is "Situation 2: Both bus lines are in a regeneration-dominant state" in the above embodiment. In Situation 2, if the voltage increase amount of the second bus line B2 is greater than the voltage increase amount of the first bus line B1, the determination unit 42 may determine the standby mode as the control mode. For example, if the above-mentioned specified condition is met during the standby mode, the control unit 4 may start executing surplus power processing.

[0114] If it is expected that there will be surplus power that cannot be consumed by the resistor 62, the control unit 4 may execute a protection stop process to prevent charging of the power storage device 3. The regenerative power utilization system 1 may further include, for example, a switch element such as an IGBT for interrupting the electrical path from the second bus line B2 side to the power storage device 3, and may turn off (open) the switch element to interrupt the electrical path during the execution of the stop process.

[0115] By providing the power consumption unit 6 in this manner, if regenerative power (surplus power) that exceeds the allowable limit is generated on the second bus line B2 side, the excess power can be consumed by the resistor 62. In other words, the allowable power consumption related to regenerative power in the regenerative power utilization system 1 can be increased. As a result, the stability of the regenerative power on the second bus line B2 can be improved.

[0116] The power consumption unit 6 may be disposed on the first bus line B1 side. However, as described above, disposing the power consumption unit 6 on the second bus line B2 side (which has a higher voltage than the first bus line B1) allows for a more constant current with the same power consumption. In other words, disposing the power consumption unit 6 on the second bus line B2 side increases the power consumption of the power consumption unit 6, so disposing the power consumption unit 6 on the second bus line B2 side rather than on the first bus line B1 side provides better overall efficiency for the regenerative power utilization system 1.

[0117] (Variation 2) A regenerative power utilization system 1 according to this variation (variation 2) will be described in detail below with reference to Fig. 6. Hereinafter, with regard to the components of the regenerative power utilization system 1 according to variation 2, components that are substantially the same as those of the regenerative power utilization system 1 of the above embodiment will be assigned the same reference numerals, and their description may be omitted as appropriate. Note that Fig. 6 simply illustrates the power storage device 3, motor system 5, and bus lines as blocks. Also, Fig. 6 omits the illustration of some components of the motor management system 100, such as the power supplies E1 and E2 and the rectifiers F1 and F2.

[0118] The regenerative power utilization system 1 according to the second modification differs from the regenerative power utilization system 1 according to the above embodiment in that it is applied to three types of motor systems 5, as shown in FIG.

[0119] Specifically, in the above embodiment, a first motor system 51 and a second motor system 52 are used as examples of at least two types of motor systems 5 to which the regenerative power utilization system 1 can be applied. In Modification 2, the at least two types of motor systems 5 to which the regenerative power utilization system 1 can be applied include three or more types of motor systems 5. Each of the three or more types of motor systems 5 has one or more motors M1 with voltage specifications that differ from one another among the three or more types of motor systems 5. The three or more types of motor systems 5 include a specific motor system 5A having one or more motors M1 with the highest voltage specifications and multiple low-voltage motor systems 5B other than the specific motor system 5A. Each of the multiple low-voltage motor systems 5B is defined as a first motor system 51 (in the above embodiment). The specific motor system 5A is defined as a second motor system 52 (in the above embodiment).

[0120] The following description will be given taking a specific motor system 5A (second motor system 52), a first low-voltage motor system 5B1 (first motor system 51), and a second low-voltage motor system 5B2 (first motor system 51) as examples of three or more types of motor systems 5. That is, the number of the plurality of low-voltage motor systems 5B is, for example, two.

[0121] The regenerative power utilization system 1 according to the second modification includes a plurality of power conversion circuits 2. It is assumed in FIG. 6 that the number of the power conversion circuits 2 is two, the same as the number of the low-voltage motor systems 5B. The power conversion circuits 2 are connected to the low-voltage bus lines B3 and the specific bus line B4 so as to satisfy the following condition: the output voltage value after boosting the voltage of the regenerative power input from each of the low-voltage bus lines B3 corresponding to the low-voltage motor systems 5B is equal to the voltage value of the specific bus line B4 corresponding to the specific motor system 5A. The connection relationship between the power storage device 3 and the power conversion circuits 2 will be described in detail below.

[0122] As shown in FIG. 6, the regenerative power utilization system 1 according to the second modification includes input / output terminals T111, T112, T113, and T211.

[0123] The power storage device 3 is assumed to have a withstand voltage higher than the maximum voltage value of the highest bus voltage in the system, e.g., a plurality of electrolytic capacitors 30 (not shown in FIG. 6 ) with a withstand voltage of 400 V. The plurality of electrolytic capacitors 30 are connected in parallel. The high-potential side terminal of the power storage device 3 is electrically connected to the input / output terminal T211 via connection points 26A and 25A. The low-potential side terminal of the power storage device 3 is electrically connected to the input / output terminal T112 (connected to GND) via connection points 24A and 22A.

[0124] The first low-voltage motor system 5B1 includes one or more motors M1 having a rated voltage of 48V and a power conversion unit (not shown in FIG. 6 ). The first low-voltage motor system 5B1 is connected to a low-voltage bus line B3 (DC 48V bus line B31: indicated as “DC48VBUS” in FIG. 6 ), which is a DC 48V bus line that corresponds to the first bus line B1 in the above embodiment. The first low-voltage motor system 5B1 receives power from a power source (not shown in FIG. 6 ) via a rectifier (not shown in FIG. 6 ) and the DC 48V bus line B31.

[0125] The DC 48V bus line B31 is electrically connected to one (referred to as the first power conversion circuit 2A) of the two power conversion circuits 2. Specifically, the high-potential side electrical path of the DC 48V bus line B31 is electrically connected to the input / output terminal T111. The input / output terminal T112 is connected to GND (e.g., frame ground), and the low-potential side electrical path of the DC 48V bus line B31 is also connected to GND.

[0126] The first power conversion circuit 2A has substantially the same circuit configuration as the power conversion circuit 2 of the above embodiment, and therefore detailed description thereof will be omitted except for the connections. In the first power conversion circuit 2A, a first end of the inductor L1 is electrically connected to the input / output terminal T111, and a second end of the inductor L1 is electrically connected to the connection point 21A. In the first power conversion circuit 2A, a first main terminal of the first switch element SW1 is electrically connected to the connection point 26A located between the connection point 25A and the high-potential terminal of the power storage device 3, and a second main terminal of the first switch element SW1 is electrically connected to the connection point 21A. In the first power conversion circuit 2A, a control terminal of the first switch element SW1 is electrically connected to the control unit 4, and the first switch element SW1 is turned on and off by receiving a control signal S1 from the control unit 4. In the first power conversion circuit 2A, the first main terminal of the second switch element SW2 is electrically connected to the connection point 21A, and the second main terminal of the second switch element SW2 is electrically connected to the connection point 22A located between the input / output terminal T112 and the connection point 24A. In the first power conversion circuit 2A, the control terminal of the second switch element SW2 is electrically connected to the control unit 4, and the second switch element SW2 is controlled to be turned on and off by receiving a control signal S2 from the control unit 4.

[0127] The second low-voltage motor system 5B2 has one or more motors M1 with a rated voltage specification of 100 V and a power conversion unit (not shown in FIG. 6 ). The second low-voltage motor system 5B2 is connected to another low-voltage bus line B3 (DC 100 V bus line B32: indicated as “DC100VBUS” in FIG. 6 ), which is a DC 100 V bus line corresponding to the first bus line B1. The second low-voltage motor system 5B2 receives power from a power source (not shown in FIG. 6 ) via a rectifier (not shown in FIG. 6 ) and the DC 100 V bus line B32.

[0128] The DC 100V bus line B32 is electrically connected to the other of the two power conversion circuits 2 (referred to as the second power conversion circuit 2B). Specifically, the high-potential side electrical path of the DC 100V bus line B32 is electrically connected to the input / output terminal T113. The low-potential side electrical path of the DC 100V bus line B32 is connected to GND.

[0129] The second power conversion circuit 2B has substantially the same circuit configuration as the power conversion circuit 2 of the above embodiment, and therefore detailed description thereof will be omitted except for the connections. In the second power conversion circuit 2B, a first end of the inductor L1 is electrically connected to the input / output terminal T113, and a second end of the inductor L1 is electrically connected to the connection point 23A. In the second power conversion circuit 2B, a first main terminal of the first switch element SW1 is electrically connected to the connection point 25A located between the input / output terminal T211 and the connection point 26A, and a second main terminal of the first switch element SW1 is electrically connected to the connection point 23A. In the second power conversion circuit 2B, a control terminal of the first switch element SW1 is electrically connected to the control unit 4, and the first switch element SW1 is turned on and off by receiving a control signal S3 from the control unit 4. In the second power conversion circuit 2B, the first main terminal of the second switch element SW2 is electrically connected to the connection point 23A, and the second main terminal of the second switch element SW2 is electrically connected to the connection point 24A located between the low potential side terminal of the power storage device 3 and the connection point 22A. In the second power conversion circuit 2B, the control terminal of the second switch element SW2 is electrically connected to the control unit 4, and the second switch element SW2 is controlled to be turned on and off by inputting a control signal S4 from the control unit 4.

[0130] The specific motor system 5A includes one or more motors M1 having a rated voltage specification of 200V and a power conversion unit (not shown in FIG. 6 ). The specific motor system 5A is connected to a specific bus line B4 (denoted as “DC200VBUS” in FIG. 6 ), which is a DC 200V bus line that corresponds to the second bus line B2 in the above embodiment. The specific motor system 5A receives power from a power source (not shown in FIG. 6 ) via a rectifier (not shown in FIG. 6 ) and the specific bus line B4.

[0131] The electric path on the high potential side of the specific bus line B4 is electrically connected to the input / output terminal T211, and the electric path on the low potential side of the specific bus line B4 is connected to GND.

[0132] In other words, the first power conversion circuit 2A and the second power conversion circuit 2B are all connected to the specific bus line B4 of the specific motor system 5A with the highest voltage specification. Due to the above connection relationship, the output voltage values ​​of the first power conversion circuit 2A and the second power conversion circuit 2B in the charge mode (boost control mode) correspond to the voltage value of the specific bus line B4 of the specific motor system 5A with the highest voltage specification. Furthermore, due to the above connection relationship, the output voltage value of the first power conversion circuit 2A in the discharge mode (step-down control mode) corresponds to the voltage value of the first low-voltage bus line (DC 48V bus line B31). The output voltage value of the second power conversion circuit 2B in the discharge mode (step-down control mode) corresponds to the voltage value of the second low-voltage bus line (DC 100V bus line B32). Simply put, the first power conversion circuit 2A is a 48V / 200V conversion circuit, and the second power conversion circuit 2B is a 100V / 200V conversion circuit.

[0133] 6, the regenerative power utilization system 1 according to the second modification includes a first measurement unit H1, a second measurement unit H2, and a third measurement unit H3. The first measurement unit H1 measures (detects) the voltage between the input / output terminals T111 and T112 and outputs a first measurement value to the control unit 4. The second measurement unit H2 measures (detects) the voltage between the input / output terminals T211 and T112 and outputs a second measurement value to the control unit 4. The third measurement unit H3 measures (detects) the voltage between the input / output terminals T113 and T112 and outputs a third measurement value to the control unit 4.

[0134] In Modification 2, the control unit 4 determines whether powering or regeneration is dominant for the DC 48V bus line B31 based on the first measurement value. The control unit 4 determines whether powering or regeneration is dominant for the specific bus line B4 based on the second measurement value. The control unit 4 determines the control mode based on a combination of these determination results. Then, the control unit 4 controls the first switch element SW1 and the second switch element SW2 in the first power conversion circuit 2A based on the determined control mode.

[0135] The control unit 4 also determines whether powering or regeneration is dominant for the DC 100V bus line B32 based on the third measurement value. The control unit 4 also determines whether powering or regeneration is dominant for the specific bus line B4 based on the second measurement value. The control unit 4 determines the control mode based on a combination of these determination results. The control unit 4 then controls the first switch element SW1 and the second switch element SW2 in the second power conversion circuit 2B based on the determined control mode.

[0136] In short, the control unit 4 of the second modification determines the control mode for each power conversion circuit 2 individually.

[0137] As described above, according to the second modification, the regenerative power utilization system 1 can be easily applied to three types of motor systems 5, thereby improving the utilization of regenerative power. Four or more types of motor systems 5 can also be applied by increasing the number of power conversion circuits 2 and establishing a similar connection relationship. For example, if a fourth motor system is added to the configuration of the second modification, a fourth power conversion circuit corresponding to the fourth motor system is added. The connection relationship can be adjusted so that the output voltage value of the fourth power conversion circuit in the charging mode corresponds to the voltage value of the specific bus line B4 of the specific motor system 5A.

[0138] (Variation 3) A regenerative power utilization system 1 according to this variation (variation 3) will be described in detail below with reference to FIG. 7. Hereinafter, with regard to the components of the regenerative power utilization system 1 according to variation 3, components that are substantially the same as those of the regenerative power utilization system 1 according to the above embodiment will be assigned the same reference numerals, and their description may be omitted as appropriate. Note that, like FIG. 6, FIG. 7 illustrates the power storage device 3, motor system 5, and bus lines as simplified blocks. Also, like FIG. 6, FIG. 7 omits the illustration of some of the components of the motor management system 100, such as the power supplies E1 and E2 and the rectifiers F1 and F2.

[0139] 7, the regenerative power utilization system 1 according to the third modification differs from the regenerative power utilization system 1 of the above embodiment in that it is applied to three or more types of motor systems 5, and is common to the above-described second modification. However, the regenerative power utilization system 1 according to the third modification differs from the above-described second modification in the connection relationship of the multiple power conversion circuits 2. Furthermore, the regenerative power utilization system 1 according to the third modification differs from the above-described second modification in that the power storage device 3 has a first power storage unit 3A and a second power storage unit 3B.

[0140] Specifically, in Modification 3, similar to Modification 2, the at least two types of motor systems 5 to which the regenerative power utilization system 1 can be applied include three or more types of motor systems 5. Each of the three or more types of motor systems 5 has one or more motors M1 with voltage specifications that differ from one another among the three or more types of motor systems 5. The three or more types of motor systems 5 include a specific motor system 5A having one or more motors M1 with the highest voltage specifications, and multiple low-voltage motor systems 5B other than the specific motor system 5A. Each of the multiple low-voltage motor systems 5B is defined as a first motor system 51 (in the above embodiment). The specific motor system 5A is defined as a second motor system 52 (in the above embodiment).

[0141] As in the above-described Modification 2, the following description will be given taking as examples the specific motor system 5A (second motor system 52), the first low-voltage motor system 5B1 (first motor system 51), and the second low-voltage motor system 5B2 (first motor system 51). That is, the number of the plurality of low-voltage motor systems 5B is, for example, two.

[0142] The regenerative power utilization system 1 according to the third modification includes a plurality of power conversion circuits 2. Note that FIG. 7 assumes that the number of the power conversion circuits 2 is two, the same as the number of the low-voltage motor systems 5B. The power conversion circuits 2 are connected to the plurality of low-voltage bus lines B3 and the specific bus line B4 so as to satisfy the following first and second conditions. The first condition is that the output voltage after boosting the voltage of the regenerative power input from the first low-voltage bus line (DC 48V bus line B31) among the plurality of low-voltage bus lines B3 corresponding to the plurality of low-voltage motor systems 5B is equal to the voltage of the second low-voltage bus line (DC 100V bus line B32). The second condition is that the output voltage after boosting the voltage of the regenerative power input from the second low-voltage bus line is equal to the voltage of the specific bus line B4 corresponding to the specific motor system 5A. The connection relationship between the power storage device 3 and the plurality of power conversion circuits 2 will be described in detail below. Note that the explanation of points common to the above-mentioned modified example 2 will be omitted as appropriate.

[0143] As described above, the power storage device 3 includes a first power storage unit 3A and a second power storage unit 3B. The first power storage unit 3A is assumed to include, for example, a plurality of electrolytic capacitors 30 (not shown in FIG. 7 ) with a withstand voltage of 200V connected in parallel. The second power storage unit 3B is assumed to include, for example, a plurality of electrolytic capacitors 30 (not shown in FIG. 7 ) with a withstand voltage of 200V connected in parallel. The high-potential terminal of the first power storage unit 3A is electrically connected to the low-potential terminal of the second power storage unit 3B via connection point 27B. The low-potential terminal of the first power storage unit 3A is electrically connected to input / output terminal T112 (connected to GND) via connection point 24B and connection point 22B. The high-potential terminal of the second power storage unit 3B is electrically connected to input / output terminal T211 via connection point 28B.

[0144] The first low-voltage motor system 5B1 is connected to the low-voltage bus line B3 (DC 48V bus line B31). The DC 48V bus line B31 is electrically connected to the first power conversion circuit 2A. Specifically, the high-potential side electrical path of the DC 48V bus line B31 is electrically connected to the input / output terminal T111. The input / output terminal T112 is connected to GND, and the low-potential side electrical path of the DC 48V bus line B31 is also connected to GND.

[0145] In the first power conversion circuit 2A, a first end of the inductor L1 is electrically connected to the input / output terminal T111, and a second end of the inductor L1 is electrically connected to the connection point 21B. In the first power conversion circuit 2A, a first main terminal of the first switch element SW1 is electrically connected to the connection point 25B located between the connection points 26B and 27B, and a second main terminal of the first switch element SW1 is electrically connected to the connection point 21B. In the first power conversion circuit 2A, a control terminal of the first switch element SW1 is electrically connected to the control unit 4, and the first switch element SW1 is controlled to be turned on and off by receiving a control signal S1 from the control unit 4. In the first power conversion circuit 2A, a first main terminal of the second switch element SW2 is electrically connected to the connection point 21B, and a second main terminal of the second switch element SW2 is electrically connected to the connection point 22B located between the input / output terminal T112 and the connection point 24B. In the first power conversion circuit 2A, the control terminal of the second switch element SW2 is electrically connected to the control unit 4, and the second switch element SW2 is controlled to be turned on and off by inputting a control signal S2 from the control unit 4.

[0146] The second low-voltage motor system 5B2 is connected to another low-voltage bus line B3 (DC 100V bus line B32). The DC 100V bus line B32 is electrically connected to the second power conversion circuit 2B. Specifically, the high-potential side electrical path of the DC 100V bus line B32 is electrically connected to the input / output terminal T113. The low-potential side electrical path of the DC 100V bus line B32 is connected to GND.

[0147] In the second power conversion circuit 2B, a first end of inductor L1 is electrically connected to input / output terminal T113 via connection point 26B, and a second end of inductor L1 is electrically connected to connection point 23B. Connection point 26B is electrically connected to connection point 27B between first power storage unit 3A and second power storage unit 3B via connection point 25B. In the second power conversion circuit 2B, a first main terminal of first switch element SW1 is electrically connected to connection point 28B, and a second main terminal of first switch element SW1 is electrically connected to connection point 23B. In the second power conversion circuit 2B, a control terminal of first switch element SW1 is electrically connected to control unit 4, and the first switch element SW1 is turned on and off when a control signal S3 is input from control unit 4. In the second power conversion circuit 2B, the first main terminal of the second switch element SW2 is electrically connected to the connection point 23B, and the second main terminal of the second switch element SW2 is electrically connected to the connection point 24B. In the second power conversion circuit 2B, the control terminal of the second switch element SW2 is electrically connected to the control unit 4, and the second switch element SW2 is controlled to be turned on and off by receiving a control signal S4 from the control unit 4.

[0148] The specific motor system 5A is connected to a specific bus line B4, which is a DC 200V bus line. The high-potential side electric path of the specific bus line B4 is electrically connected to the input / output terminal T211, and the low-potential side electric path of the specific bus line B4 is connected to GND.

[0149] In short, due to the above connection relationship, the output voltage value of the first power conversion circuit 2A in the charging mode (boost control mode) corresponds to the voltage value of the DC 100V bus line B32. The output voltage value of the second power conversion circuit 2B in the charging mode (boost control mode) corresponds to the voltage value of the specific bus line B4. Simply put, the first power conversion circuit 2A is a 48V / 100V conversion circuit, and the second power conversion circuit 2B is a 100V / 200V conversion circuit.

[0150] In the regenerative power utilization system 1 according to the third modification, the first measurement unit H1 also measures (detects) the voltage between the input / output terminals T111 and T112 and outputs a first measurement value to the control unit 4. The second measurement unit H2 measures (detects) the voltage between the input / output terminals T211 and T112 and outputs a second measurement value to the control unit 4. The third measurement unit H3 measures (detects) the voltage between the input / output terminals T113 and T112 and outputs a third measurement value to the control unit 4.

[0151] In Modification 3, the control unit 4 determines whether powering or regeneration is dominant for the DC 48V bus line B31 based on the first measurement value. The control unit 4 determines whether powering or regeneration is dominant for the specific bus line B4 based on the second measurement value. The control unit 4 determines the control mode based on a combination of these determination results. The control unit 4 then controls the first switch element SW1 and the second switch element SW2 in the first power conversion circuit 2A based on the determined control mode. In the charge mode, regenerative power on the DC 48V bus line B31 side is stored in the first power storage unit 3A, and in the discharge mode, the regenerative power is discharged from the first power storage unit 3A and used as power for powering on the DC 48V bus line B31 side.

[0152] The control unit 4 also determines, based on the third measurement value, whether powering or regeneration is dominant for the DC 100V bus line B32. The control unit 4 also determines, based on the second measurement value, whether powering or regeneration is dominant for the specific bus line B4. The control unit 4 determines the control mode based on a combination of these determination results. The control unit 4 then controls the first switch element SW1 and the second switch element SW2 in the second power conversion circuit 2B according to the determined control mode. In the charge mode, the regenerative power on the DC 100V bus line B32 side is stored in the second power storage unit 3B, and in the discharge mode, the regenerative power is discharged from the second power storage unit 3B and used as power for powering on the DC 100V bus line B32 side.

[0153] The regenerated power on the specific bus line B4 side is stored in both the first power storage unit 3A and the second power storage unit 3B.

[0154] As described above, according to Modification 3, similar to Modification 2, the regenerative power utilization system 1 can be easily applied to three types of motor systems 5, thereby improving the utilization of regenerative power. Note that four or more types of motor systems 5 can also be applied by increasing the number of power conversion circuits 2 and establishing similar connections. For example, if a fourth motor system is added to the configuration of Modification 3, a fourth power conversion circuit corresponding to the fourth motor system is added. The connections are adjusted so that the output voltage value of the fourth power conversion circuit in the charging mode corresponds to the voltage value of the low-voltage bus line B3 of the first low-voltage motor system 5B1. Thereafter, similar to Modification 3, the connections are adjusted so that the output voltage value of the first power conversion circuit 2A in the charging mode corresponds to the voltage value of the low-voltage bus line B3 of the second low-voltage motor system 5B2.

[0155] (Other Modifications) Functions similar to those of the regenerative power utilization system 1 according to the above-described embodiment and modification 1 may be embodied as a control method, a computer program, a non-transitory recording medium on which a computer program is recorded, or the like.

[0156] The regenerative power utilization system 1 (particularly the control unit 4) in the present disclosure includes a computer system. The computer system is primarily composed of a processor and a memory as hardware. The processor executes a program stored in the memory of the computer system to realize the functions of the regenerative power utilization system 1 (particularly the control unit 4) in the present disclosure. The program may be pre-stored in the memory of the computer system, provided via a telecommunications line, or provided by being stored on a non-transitory recording medium readable by the computer system, such as a memory card, an optical disk, or a hard disk drive. The processor of the computer system is composed of one or more electronic circuits including a semiconductor integrated circuit (IC) or a large-scale integrated circuit (LSI). The integrated circuits, such as ICs and LSIs, are referred to by different names depending on the degree of integration, and include integrated circuits called system LSIs, very large-scale integration (VLSI), or ultra-large-scale integration (ULSI). Furthermore, a field-programmable gate array (FPGA), which is programmed after the LSI is manufactured, or a logic device capable of reconfiguring the connections within the LSI or the circuit partitions within the LSI, can also be employed as a processor. Multiple electronic circuits may be integrated into a single chip or distributed across multiple chips. Multiple chips may be integrated into a single device or distributed across multiple devices. The computer system referred to here includes a microcontroller having one or more processors and one or more memories. Therefore, the microcontroller is also composed of one or more electronic circuits, including a semiconductor integrated circuit or a large-scale integrated circuit.

[0157] Furthermore, it is not essential that the multiple functions of the regenerative power utilization system 1 be concentrated in one housing (casing) as in the above embodiment and modified examples 1 to 3. For example, the components of the regenerative power utilization system 1 may be distributed across multiple housings. Conversely, the multiple functions of the regenerative power utilization system 1 may be concentrated in one housing as in the above embodiment and modified examples 1 to 3.

[0158] (Summary) The above-described embodiments and the like disclose the following aspects.

[0159] A regenerative power utilization system (1) according to a first aspect is configured to utilize regenerative power generated by at least two types of motor systems (5). The at least two types of motor systems (5) include a first motor system (51) having one or more first motors (M11) and a second motor system (52) having one or more second motors (M12) with a higher voltage specification than the one or more first motors (M11). The regenerative power utilization system (1) includes a step-up / step-down power conversion circuit (2), an electricity storage device (3), and a control unit (4). The power conversion circuit (2) is connected between a first bus line (B1) for supplying power to the first motor system (51) and a second bus line (B2) for supplying power to the second motor system (52). The power conversion circuit (2) has a plurality of switch elements (SW0) and performs switching operations for the plurality of switch elements (SW0). The power storage device (3) is connected to the power conversion circuit (2) on the first bus line (B1) side or the second bus line (B2) side of the power conversion circuit (2). The control unit (4) controls a plurality of switch elements (SW0) so as to charge the power storage device (3) with regenerative power. When a specific condition is satisfied, the control unit (4) controls the plurality of switch elements (SW0) so that the stored power of the power storage device (3) is used as power for driving the first motor system (51).

[0160] According to the above aspect, the power storage device (3) is charged with regenerative power generated by the first motor system (51) and the second motor system (52) having different voltage specifications for the motor (M1), and the power stored in the power storage device (3) is used to power the first motor system (51). As a result, the regenerative power utilization system (1) has the advantage of being able to improve the utilization of regenerative power.

[0161] In the first aspect of the regenerative power utilization system (1) according to the second aspect, the power storage device (3) is connected closer to the second bus line (B2) than the power conversion circuit (2). The control unit (4) controls a plurality of switch elements (SW0) to boost the regenerative power generated in the first motor system (51) and charge the power storage device (3). The control unit (4) also controls the plurality of switch elements (SW0) to lower the voltage of the power stored in the power storage device (3) and use it as power for propelling the first motor system (51).

[0162] According to the above aspect, for example, by using a high-voltage withstand electric storage device (3), it becomes easier to charge the electric storage device (3) more efficiently without stepping down the regenerative power generated by the second motor system (52) with high voltage specifications.

[0163] In the regenerative power utilization system (1) according to the third aspect, in the first or second aspect, the control unit (4) has a determination unit (41) and a decision unit (42). The determination unit (41) determines the magnitude of the amount of running power generated on the first bus line (B1) side and the amount of regenerative power generated on the second bus line (B2) side. The decision unit (42) decides one control mode from a plurality of control modes based on the decision result by the determination unit (41). The control unit (4) controls the plurality of switch elements (SW0) in the control mode decided by the decision unit (42). The plurality of control modes include at least a step-up control mode and a step-down control mode.

[0164] According to the above aspect, it is possible to realize more appropriate control of the power conversion circuit (2) in accordance with the states of the running power and the regenerative power on each of the first bus line (B1) side and the second bus line (B2) side.

[0165] In the third aspect of the regenerative power utilization system (1) according to the fourth aspect, a determination unit (41) compares a measurement value for each of the first bus line (B1) and the second bus line (B2) with a predetermined reference value. When the measurement value for each of the first bus line (B1) and the second bus line (B2) is greater than the predetermined reference value, the determination unit (41) determines that a regeneration-dominant state exists in which the amount of regenerative power generated is greater than the amount of power-running power generated. When the measurement value for each of the first bus line (B1) and the second bus line (B2) is equal to or less than the predetermined reference value, the determination unit (41) determines that a power-running-dominant state exists in which the amount of regenerative power generated is smaller than the amount of power-running power generated. The measurement value is a value related to at least one of a current value, a voltage value, a current rise rate, and a voltage rise rate.

[0166] According to the above aspect, it is possible to improve the accuracy of determining whether the first bus line (B1) and the second bus line (B2) are in a regeneration-dominant state or a power-running-dominant state.

[0167] In the fourth aspect of the regenerative power utilization system (1) according to the fifth aspect, the control unit (4) controls the multiple switch elements (SW0) in the following case. The control unit (4) then increases the voltage on the other bus line side so that a current flows from the power storage device (3) to the other bus line side in a power running dominant state. The following case is when the determination result by the determination unit (41) indicates that one of the first bus line (B1) and the second bus line (B2) is in a regeneration dominant state and the other bus line is in a power running dominant state.

[0168] According to the above aspect, when one of the first bus line (B1) and the second bus line (B2) is in a regeneration-dominant state and the other bus line is in a power-running-dominant state, more appropriate control of the power conversion circuit (2) can be achieved.

[0169] In the fourth or fifth aspect of the regenerative power utilization system (1) according to the sixth aspect, the control unit (4) controls the multiple switch elements (SW0) in the following case. The control unit (4) increases the voltage on the second bus line (B2) side so that a current flows from the power storage device (3) to the second bus line (B2). The following case is when the determination result by the determination unit (41) indicates that both the first bus line (B1) and the second bus line (B2) are in a regeneration-dominant state.

[0170] According to the above aspect, when both the first bus line (B1) and the second bus line (B2) are in a regeneration dominant state, more appropriate control of the power conversion circuit (2) can be achieved.

[0171] The regenerative power utilization system (1) according to the seventh aspect is as follows in any one of the fourth to sixth aspects: the control unit (4) stops the switching operation so that no current flows from the power storage device (3) to both the first bus line (B1) and the second bus line (B2) in the following cases: when the determination result by the determination unit (41) indicates that both the first bus line (B1) and the second bus line (B2) are in a power running dominant state.

[0172] According to the above aspect, when both the first bus line (B1) and the second bus line (B2) are in a power running dominant state, more appropriate control of the power conversion circuit (2) can be achieved.

[0173] The regenerative power utilization system (1) according to the eighth aspect is as follows in any one of the third to seventh aspects. That is, the control unit (4) sets a target voltage value higher than a current voltage value for one of the first bus line (B1) and the second bus line (B2) through which current flows from the regenerative power utilization system (1) in accordance with the determination result by the determination unit (42). Then, the control unit (4) adjusts the duty cycles related to the switching control of the plurality of switch elements (SW0).

[0174] According to the above aspect, the voltage step-up / step-down control of the power conversion circuit (2) is more appropriately executed.

[0175] A regenerative power utilization system (1) according to a ninth aspect is the system of any one of the first to eighth aspects, further including a capacitor (C1) arranged closer to the first bus line (B1) than the power conversion circuit (2). The first bus line (B1) has a first electrical circuit (B11) on a high potential side and a second electrical circuit (B12) on a low potential side. A first end of the capacitor (C1) is electrically connected to the first electrical circuit (B11), and a second end of the capacitor (C1) is electrically connected to the second electrical circuit (B12).

[0176] According to the above aspect, by providing the capacitor (C1), when the regenerative power suddenly increases on the first bus line (B1) side, the rate of voltage increase can be suppressed in the transient response of the regenerative power utilization system (1).

[0177] A regenerative power utilization system (1) according to a tenth aspect is any one of the first to ninth aspects, further including a power consumption unit (6). The power consumption unit (6) has a specific switch element (61) whose on / off switching is controlled by a control unit (4), and a resistor (62) connected in series with the specific switch element (61). The power consumption unit (6) is arranged closer to the second bus line (B2) than the power conversion circuit (2). The control unit (4) controls the specific switch element (61) to be on so that surplus power generated on the second bus line (B2) side is consumed by the resistor (62).

[0178] According to the above aspect, when regenerative power (surplus power) that exceeds the allowable limit is generated on the second bus line (B2), the excess power can be consumed by the resistor (62). In other words, the allowable power consumption of the regenerative power in the regenerative power utilization system (1) can be increased. As a result, the stability of the regenerative power on the second bus line (B2) can be improved.

[0179] Regarding the regenerative power utilization system (1) according to an eleventh aspect, in any one of the first to tenth aspects, the at least two types of motor systems (5) include three or more types of motor systems (5). Each of the three or more types of motor systems (5) has one or more motors (M1) with voltage specifications that differ from one another among the three or more types of motor systems (5). The three or more types of motor systems (5) include a specific motor system (5A) having one or more motors (M1) with the highest voltage specifications, and a plurality of low-voltage motor systems (5B) other than the specific motor system (5A). Each of the plurality of low-voltage motor systems (5B) is defined as a first motor system (51). The specific motor system (5A) is defined as a second motor system (52). The regenerative power utilization system (1) includes a plurality of power conversion circuits (2). The plurality of power conversion circuits (2) are connected to a plurality of low-voltage bus lines (B3) and a specific bus line (B4) so ​​as to satisfy the following conditions: The next point is that the output voltage value after boosting the voltage of the regenerative power input from each of the plurality of low-voltage bus lines (B3) corresponding to the plurality of low-voltage motor systems (5B) becomes the voltage value of the specific bus line (B4) corresponding to the specific motor system (5A).

[0180] According to the above aspect, it becomes easier to apply the regenerative power utilization system (1) to three or more types of motor systems (5), and improvements can be made in the utilization of regenerative power.

[0181] Regarding the regenerative power utilization system (1) according to a twelfth aspect, in any one of the first to tenth aspects, the at least two types of motor systems (5) include three or more types of motor systems (5). Each of the three or more types of motor systems (5) has one or more motors (M1) with voltage specifications that differ from one another among the three or more types of motor systems (5). The three or more types of motor systems (5) include a specific motor system (5A) having one or more motors (M1) with the highest voltage specifications, and a plurality of low-voltage motor systems (5B) other than the specific motor system (5A). Each of the plurality of low-voltage motor systems (5B) is defined as a first motor system (51). The specific motor system (5A) is defined as a second motor system (52). The regenerative power utilization system (1) includes a plurality of power conversion circuits (2). The plurality of power conversion circuits (2) are connected to the plurality of low-voltage bus lines (B3) and the specific bus line (B4) so ​​as to satisfy the following first and second points: The first point is that the output voltage value after boosting the voltage of regenerative power input from a first low-voltage bus line (DC 48V bus line B31) among the plurality of low-voltage bus lines (B3) corresponding to the plurality of low-voltage motor systems (5B) respectively becomes the voltage value of a second low-voltage bus line (DC 100V bus line B32); The second point is that the output voltage value after boosting the voltage of regenerative power input from the second low-voltage bus line (DC 100V bus line B32) becomes the voltage value of a specific bus line (B4) corresponding to the specific motor system (5A).

[0182] According to the above aspect, it becomes easier to apply the regenerative power utilization system (1) to three or more types of motor systems (5), and improvements can be made in the utilization of regenerative power.

[0183] A control method according to a thirteenth aspect relates to utilization of regenerative power generated by at least two types of motor systems (5). The at least two types of motor systems (5) include a first motor system (51) having one or more first motors (M11) and a second motor system (52) having one or more second motors (M12) with a higher voltage specification than the one or more first motors (M11). The control method includes a first control step and a second control step. In the first control step, a plurality of switch elements (SW0) in a buck-boost power conversion circuit (2) having a plurality of switch elements (SW0) and performing switching operations on the plurality of switch elements (SW0) are controlled to charge a power storage device (3) with the regenerative power. The power conversion circuit (2) is connected between a first bus line (B1) for supplying power to the first motor system (51) and a second bus line (B2) for supplying power to the second motor system (52). The power storage device (3) is connected to the power conversion circuit (2) on the side of the first bus line (B1) or the side of the second bus line (B2) relative to the power conversion circuit (2). In the second control step, when a specific condition is satisfied, a plurality of switch elements (SW0) are controlled so that stored power in the power storage device (3) is used as power for driving the first motor system (51).

[0184] According to the above aspect, it is possible to provide a control method that can improve utilization of regenerative power.

[0185] A program according to a fourteenth aspect is a program for causing one or more processors to execute the control method according to the thirteenth aspect.

[0186] According to the above aspect, it is possible to provide a function that can improve the utilization of regenerative power.

[0187] The configurations according to the second to twelfth aspects are not essential for the regenerative power utilization system (1) and may be omitted as appropriate.

[0188] REFERENCE SIGNS LIST 1 Regenerative power utilization system 2 Power conversion circuit 3 Power storage device 4 Control unit 41 Judgment unit 42 Decision unit 5 Motor system 51 First motor system 52 Second motor system 5A Specific motor system 5B Low-voltage motor system 6 Power consumption unit 61 Specific switch element 62 Resistor B1 First bus line B11 First electric circuit B12 Second electric circuit B2 Second bus line B3 Low-voltage bus line B31 DC 48V bus line (first low-voltage bus line) B32 DC 100V bus line (second low-voltage bus line) B4 Specific bus line C1 Capacitor G1 Power conversion unit M1 Motor M11 First motor M12 Second motor SW0 Switch element

Claims

1. A regenerative power utilization system configured to utilize regenerative power generated by at least two types of motor systems, the at least two types of motor systems including a first motor system having one or more first motors, and a second motor system having one or more second motors having higher voltage specifications than the one or more first motors; a step-up / step-down power conversion circuit connected between a first bus line for supplying power to the first motor system and a second bus line for supplying power to the second motor system, the step-up / step-down power conversion circuit having a plurality of switch elements and performing switching operations for the plurality of switch elements; an electric storage device connected to the power conversion circuit on the side of the first bus line or the side of the second bus line relative to the power conversion circuit; a control unit that controls the plurality of switch elements so as to charge the power storage device with the regenerative power; Equipped with the control unit controls the plurality of switch elements so that stored power in the power storage device is used as power for driving the first motor system when a specific condition is satisfied. Regenerative power utilization system.

2. the power storage device is connected to a side of the power conversion circuit that is closer to the second bus line, The control unit controlling the plurality of switch elements so as to boost the regenerative power generated by the first motor system and charge the power storage device; controlling the plurality of switch elements so that the stored power of the power storage device is reduced in voltage and used as the running power of the first motor system; The regenerative power utilization system according to claim 1 .

3. The control unit a determination unit that determines which of the amounts of running power and regenerative power generated on each of the first bus line side and the second bus line side is larger; a determination unit that determines one control mode from a plurality of control modes based on a determination result by the determination unit, the control unit controls the plurality of switch elements in the control mode determined by the determination unit, The plurality of control modes include at least a voltage step-up control mode and a voltage step-down control mode. The regenerative power utilization system according to claim 1 or 2.

4. The determination unit comparing the measured values ​​for each of the first bus line and the second bus line with a predetermined reference value; determining a regeneration-dominant state in which the amount of generated regenerative power is greater than the amount of generated traction power for each of the first bus line and the second bus line when the measured value is greater than the predetermined reference value; determining, for each of the first bus line and the second bus line, when the measured value is equal to or less than the predetermined reference value, that a powering dominant state is being established in which the amount of generated regenerative power is smaller than the amount of generated power; The measurement value is a value related to at least one of a current value, a voltage value, a current rise rate, and a voltage rise rate. The regenerative power utilization system according to claim 3 .

5. when the determination result by the determination unit indicates that one of the first bus line and the second bus line is in the regeneration dominant state and the other bus line is in the power running dominant state, the control unit controls the plurality of switch elements to increase a voltage on the other bus line side so that a current flows from the power storage device to the other bus line side that is in the power running dominant state. The regenerative power utilization system according to claim 4.

6. when a determination result by the determination unit indicates that both the first bus line and the second bus line are in the regeneration dominant state, the control unit controls the plurality of switch elements to increase a voltage on the second bus line side so that a current flows from the power storage device to the second bus line side. The regenerative power utilization system according to claim 4.

7. when a determination result by the determination unit indicates that both the first bus line and the second bus line are in the powering dominant state, the control unit stops the switching operation so that no current flows from the power storage device to both the first bus line and the second bus line. The regenerative power utilization system according to claim 4.

8. the control unit adjusts duties related to switching control of the plurality of switch elements, with a target voltage value being higher than a current voltage value for one of the first bus line and the second bus line through which a current flows from the regenerative power utilization system, according to a determination result by the determination unit. The regenerative power utilization system according to claim 3 .

9. a capacitor disposed closer to the first bus line than the power conversion circuit; the first bus line has a first electrical path on a high potential side and a second electrical path on a low potential side; a first end of the capacitor electrically connected to the first electrical path, and a second end of the capacitor electrically connected to the second electrical path; The regenerative power utilization system according to claim 1 or 2.

10. a power consumption unit having a specific switch element whose on / off switching is controlled by the control unit and a resistor connected in series with the specific switch element; the power consumption unit is arranged closer to the second bus line than the power conversion circuit, the control unit controls the specific switch element to be turned on so that surplus power generated on the second bus line side is consumed by the resistor. The regenerative power utilization system according to claim 1 or 2.

11. the at least two types of motor systems include three or more types of motor systems, each of the three or more types of motor systems having one or more motors with voltage specifications that differ from one another among the three or more types of motor systems; the three or more types of motor systems include a specific motor system having the one or more motors with the highest voltage specifications, and a plurality of low-voltage motor systems other than the specific motor system; each of the plurality of low voltage motor systems is defined as the first motor system; the specific motor system is defined as the second motor system; The regenerative power utilization system includes a plurality of the power conversion circuits, the plurality of power conversion circuits are connected to the plurality of low-voltage bus lines and the specific bus lines so that an output voltage value after boosting the voltage of the regenerative power input from each of the plurality of low-voltage bus lines corresponding to the plurality of low-voltage motor systems becomes a voltage value of the specific bus line corresponding to the specific motor system; The regenerative power utilization system according to claim 1 or 2.

12. the at least two types of motor systems include three or more types of motor systems, each of the three or more types of motor systems having one or more motors with voltage specifications that differ from one another among the three or more types of motor systems; the three or more types of motor systems include a specific motor system having the one or more motors with the highest voltage specifications, and a plurality of low-voltage motor systems other than the specific motor system; each of the plurality of low voltage motor systems is defined as the first motor system; the specific motor system is defined as the second motor system; The regenerative power utilization system includes a plurality of the power conversion circuits, the plurality of power conversion circuits are connected to the plurality of low-voltage bus lines and the specific bus lines among the plurality of low-voltage bus lines respectively corresponding to the plurality of low-voltage motor systems so that an output voltage value after boosting the voltage of the regenerative power input from a first low-voltage bus line becomes a voltage value of a second low-voltage bus line, and so that an output voltage value after boosting the voltage of the regenerative power input from the second low-voltage bus line becomes a voltage value of a specific bus line corresponding to the specific motor system; The regenerative power utilization system according to claim 1 or 2.

13. A control method for utilizing regenerative electric power generated by at least two types of motor systems, wherein the at least two types of motor systems include a first motor system having one or more first motors, and a second motor system having one or more second motors having a voltage specification higher than that of the one or more first motors; a first control step of controlling a plurality of switch elements in a step-up / step-down power conversion circuit that is connected between a first bus line for supplying power to the first motor system and a second bus line for supplying power to the second motor system, the step-up / step-down power conversion circuit having a plurality of switch elements and performing switching operations for the plurality of switch elements, to charge an electric storage device that is connected to the power conversion circuit on the side of the first bus line or the side of the second bus line relative to the power conversion circuit, with the regenerative power; a second control step of controlling the plurality of switch elements so that stored power of the power storage device is used as running power of the first motor system when a specific condition is satisfied; Including, Control method.

14. A program for causing one or more processors to execute the control method according to claim 13.