Power conversion device and program

Abstract

A power conversion device is provided with: an inverter (20); a motor (10) having an armature winding (11); an inter-power-storage-unit switch (40) provided on an inter-power-storage-unit electrical path (24) that electrically connects the negative electrode terminal of the first power storage unit (31) and the positive electrode terminal of the second power storage unit (32); bypass switches (50, 51); motor-side electrical paths (25-28) that electrically connect the armature winding and the electrical paths between the power storage units; and a control unit (100). When it is determined that there is a request for power transmission between the first power storage unit and the second power storage unit, the control unit performs power transmission control between the first power storage unit and the second power storage unit by opening and closing the inverter in a state in which the operation mode of the inter-power-storage-unit switch and the bypass switch is either a first mode or a second mode. The first mode is to turn on the switch between the power storage parts and turn off the bypass switch, and the second mode is to turn off the switch between the power storage parts and turn on the bypass switch.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2022-144022 filed on September 9, 2022, and the contents thereof are incorporated herein by reference. Technical Field

[0002] The present disclosure relates to a power conversion device and a program. Background Art

[0003] In the past, as described in Patent Document 1, there is known a vehicle-mounted system including a motor, an inverter electrically connected to the armature winding of the motor, and a first and a second power storage unit. The system includes a relay for switching the connection state of the first and the second power storage units to a series connection state or a parallel connection state. Thus, the first and the second power storage units can be charged regardless of whether the external charger with a charging voltage of 400V or the external charger with a charging voltage of 800V. In addition, when using an external charger with a charging voltage of 400V, since the connection state of the first and the second power storage units is a parallel connection state, the system voltage can be reduced to charge the first and the second power storage units. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent No. 6930306 Summary of the invention

[0005] There is a great demand for a new power conversion device capable of transmitting electric power between a first power storage unit and a second power storage unit.

[0006] A main object of the present disclosure is to provide a power conversion device and a program capable of transmitting electric power between a first power storage unit and a second power storage unit.

[0007] The present disclosure provides a power conversion device, including: a high potential side electrical path, which can be electrically connected to a positive terminal of a first power storage unit; a low potential side electrical path electrically connectable to the negative terminal of the second power storage unit; an inverter including an upper arm switch electrically connected to the high potential side electrical path and a lower arm switch electrically connected to the low potential side electrical path; and The electric motor has an armature winding, wherein the armature winding is electrically connected to a connection point between the upper arm switch and the lower arm switch via a conductive member. The power conversion device includes: an inter-storage unit switch provided in an inter-storage unit electrical path electrically connecting a negative terminal of the first storage unit and a positive terminal of the second storage unit; a bypass switch for performing at least one of an electrical connection between negative terminals of the first power storage unit and the second power storage unit and an electrical connection between positive terminals of the first power storage unit and the second power storage unit; a motor-side electrical path electrically connecting the armature winding or the conductive member and the electrical path between the power storage units; and Control Department, The control unit determines whether there is a request for power transmission between the first power storage unit and the second power storage unit, When it is determined that there is a request for power transmission, power transmission between the first power storage unit and the second power storage unit is controlled by opening and closing the inverter while the operation modes of the switch between the power storage units and the bypass switch are set to a first mode or a second mode, the first mode being to turn on the switch between the power storage units and to turn off the bypass switch, and the second mode being to turn off the switch between the power storage units and to turn on the bypass switch.

[0008] By setting the operation mode of the switch between the power storage units and the bypass switch to the first mode or the second mode, a circuit is formed that can transmit power between the first power storage unit and the second power storage unit via the inverter and the armature winding. By opening and closing the inverter in the first mode or the second mode, power can be transmitted between the first power storage unit and the second power storage unit. In addition, the structure of the motor and the inverter can be used for power transmission. Therefore, a power conversion device with a simplified structure for power transmission between the first and second power storage units can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The above objects, other objects, features and advantages of the present disclosure will become more apparent with reference to the accompanying drawings and the following detailed description. Figure 1 It is a diagram showing the overall configuration of the system according to the first embodiment. Figure 2 is a flowchart showing the steps of the power transmission control process. Figure 3 It is a diagram showing a specific example of a power transmission request. Figure 4 2 is a diagram showing the operation of the switch in the high voltage charging mode. Figure 5 2 is a diagram showing the operation of the switch in the high voltage charging mode. Figure 6 is a diagram showing an equivalent circuit in the high voltage charging mode. Figure 7 2 is a diagram showing the operation of the switch in the low voltage charging mode. Figure 82 is a diagram showing the operation of the switch in the low voltage charging mode. Fig. 9 is a diagram showing an equivalent circuit in the low voltage charging mode. Fig.10 It is a diagram showing the overall configuration of the system according to the second embodiment. Fig.11 It is a diagram showing the overall configuration of a system according to a modified example of the second embodiment. Fig.12 It is a diagram showing the overall configuration of a system according to a modified example of the second embodiment. Fig.13 It is a diagram showing the overall configuration of a system according to a modified example of the second embodiment. Fig.14 It is a diagram showing the overall configuration of a system according to the third embodiment. Fig.15 : is a timing chart showing the abnormality diagnosis process of the switch. Fig.16 : is a timing chart showing the abnormality diagnosis process of the switch. Fig.17 : is a timing chart showing the abnormality diagnosis process of the switch. Fig.18 It is a diagram showing the overall configuration of a system according to a modification of the third embodiment. Fig.19 This is a diagram showing the operation mode of the switch when precharging the first storage battery. Fig. 20 This is a diagram showing the operation mode of the switch when precharging the second storage battery. Fig.21 It is a diagram showing the overall configuration of a system according to a modification of the third embodiment. Fig. 22 This is a diagram showing the operation mode of the switch when precharging the first storage battery. Fig.23 It is a diagram showing the overall configuration of a system according to the fourth embodiment. Fig.24 It is a diagram showing the overall configuration of a system according to the fifth embodiment. Fig.25 2 is a diagram showing the operation of the switch in the high voltage charging mode. Fig.26 2 is a diagram showing the operation of the switch in the low voltage charging mode. Fig. 27 It is an overall structural diagram of the system according to the sixth embodiment. Fig.28 It is an overall structural diagram of the system according to the seventh embodiment. Fig.29 It is an overall structural diagram of a system according to another embodiment. Fig.30 It is an overall structural diagram of a system according to another embodiment. Fig.31 It is an overall structural diagram of a system according to another embodiment. Fig.32 2 is a diagram showing the operation of the switch in the low voltage charging mode. Fig.33 It is an overall structural diagram of a system according to another embodiment. Fig.34 It is an overall structural diagram of a system according to another embodiment. Fig.35 Detailed description of the invention is a flowchart showing the procedure of a power transmission control process according to another embodiment. DETAILED DESCRIPTION

[0010] Hereinafter, multiple embodiments are described with reference to the accompanying drawings. In multiple embodiments, functionally and / or structurally corresponding parts and / or associated parts are sometimes marked with the same reference numerals or reference numerals that are different by more than one hundred. For the corresponding parts and / or associated parts, reference can be made to the description of other embodiments.

[0011] <First embodiment> Hereinafter, a first embodiment of the power conversion device of the present disclosure will be described with reference to the drawings. The power conversion device of this embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle, and constitutes an in-vehicle system.

[0012] The system installed in the vehicle CA includes a power conversion device. Figure 1 As shown, the power conversion device includes a motor 10, an inverter 20, a high potential side electrical path 22H and a low potential side electrical path 22L. The motor 10 is a three-phase synchronous machine, including a star-connected U, V, and W phase armature winding 11 and a rotor not shown. The armature winding 11 of each phase is configured to be staggered by 120° in electrical angle. The motor 10 is, for example, a permanent magnet synchronous machine. The rotor can transmit power to the drive wheels of the vehicle CA. Therefore, the motor 10 is a source of torque that causes the vehicle CA to move.

[0013] The inverter 20 includes a series connection of three corresponding upper arm switches SWH and lower arm switches SWL. The upper arm switch SWH is connected in reverse parallel to an upper arm diode DH as a freewheeling diode, and the lower arm switch SWL is connected in reverse parallel to a lower arm diode DL as a freewheeling diode. In the present embodiment, each switch SWH, SWL is an IGBT.

[0014] The inverter 20 includes a smoothing capacitor 21. A high potential side terminal of the smoothing capacitor 21 is connected to a first end side of a long high potential side electrical path 22H. A low potential side terminal of the smoothing capacitor 21 is connected to a first end side of a long low potential side electrical path 22L. In addition, the smoothing capacitor 21 may also be provided outside the inverter 20.

[0015] In each phase, the connection point between the emitter as the low potential side terminal of the upper arm switch SWH and the collector as the high potential side terminal of the lower arm switch SWL is connected to the first end of the armature winding 11 via a conductive member 23 such as a busbar. The second ends of the armature windings 11 of each phase are connected to each other at a neutral point. In addition, in the present embodiment, the number of turns of the armature windings 11 of each phase is set to be the same. As a result, the inductance of the armature windings 11 of each phase is set to be the same.

[0016] The collector of the upper arm switch SWH of each phase is connected to the high potential side electric path 22H, and the emitter of the lower arm switch SWL of each phase is connected to the low potential side electric path 22L.

[0017] The system includes a first battery 31 (equivalent to the "first power storage unit") and a second battery 32 (equivalent to the "second power storage unit"). Each battery 31, 32 serves as a power supply source for driving the rotor of the motor 10 to rotate. Each battery 31, 32 is a battery pack constituted as a series connection of single cells, i.e., battery cells. The positive terminal of the first battery 31 is connected to the high potential side electrical path 22H, and the negative terminal of the second battery 32 is connected to the low potential side electrical path 22L. The terminal voltages (e.g., rated voltages) of the battery cells constituting the battery pack are, for example, set to be the same as each other. The battery cells are, for example, secondary batteries such as lithium-ion batteries.

[0018] Each battery 31, 32 can be charged by an external charger to be described later provided outside the vehicle CA. The external charger is, for example, a stationary charger. A positive electrode side connection portion to which a positive terminal of an external charger can be connected is provided at a second end side of the high potential side electrical path 22H on the opposite side to the connection point side of the smoothing capacitor 21. A negative electrode side connection portion to which a negative terminal of an external charger can be connected is provided at a second end side of the low potential side electrical path 22L on the opposite side to the connection point side of the smoothing capacitor 21.

[0019] The power conversion device includes a main switch for electrically connecting or disconnecting the first and second storage batteries 31 and 32 and the inverter 20. In detail, as the main switch, a high potential side main switch SMRH and a low potential side main switch SMRL are provided. In addition, the power conversion device includes a charging switch for electrically connecting or disconnecting the external charger and the first and second storage batteries 31 and 32. In detail, as the charging switch, a high potential side charging switch DCRH and a low potential side charging switch DCRL are provided. In the present embodiment, each switch SMRH, SMRL, DCRH, DCRL is a mechanical relay. Each switch SMRH, SMRL, DCRH, DCRL blocks the flow of bidirectional current when it is disconnected, and allows the flow of bidirectional current when it is connected. In the high potential side electrical path 22H, a high potential side main switch SMRH and a high potential side charging switch DCRH are provided in sequence from the inverter 20 side. In the low potential side electrical path 22L, a low potential side main switch SMRL and a low potential side charging switch DCRL are provided in order from the inverter 20 side. In addition, the high potential side main switch SMRH, the low potential side main switch SMRL, the high potential side charging switch DCRH and the low potential side charging switch DCRL are not limited to mechanical relays, and may be, for example, semiconductor switching elements.

[0020] The power conversion device includes an inter-battery switch 40, an inter-negative electrode bypass switch 50, and a motor-side switch 60 as switches for switching the connection mode of the first storage battery 31 and the second storage battery 32 to the external charger. In the present embodiment, the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 are mechanical relays. The inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 prevent the flow of bidirectional current when they are disconnected, and allow the flow of bidirectional current when they are connected. In addition, the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 are not limited to mechanical relays, and may also be semiconductor switch elements, for example.

[0021] The inter-battery switch 40 is provided in the inter-battery electrical path 24 (corresponding to the "inter-storage unit electrical path") that connects the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32. By turning on the inter-battery switch 40, the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are electrically connected. On the other hand, by turning off the inter-battery switch 40, the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are electrically disconnected.

[0022] The negative electrode bypass switch 50 connects the negative terminal of the first battery 31 and the low potential side electrical path 22L. By turning on the negative electrode bypass switch 50, the negative terminal of the first battery 31 and the negative terminal of the second battery 32 are electrically connected. On the other hand, by turning off the negative electrode bypass switch 50, the negative terminal of the first battery 31 and the negative terminal of the second battery 32 are electrically disconnected.

[0023] The motor-side switch 60 is provided in the motor-side electrical path 25, which connects a position of the inter-battery electrical path 24 closer to the second battery 32 than the inter-battery switch 40 and the neutral point of the armature winding 11. By turning on the motor-side switch 60, the neutral point of the armature winding 11 and the positive terminal of the second battery 32 are electrically connected. On the other hand, by turning off the motor-side switch 60, the neutral point of the armature winding 11 and the positive terminal of the second battery 32 are electrically disconnected.

[0024] As the operation mode of the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60, a series neutral point mode (equivalent to the "first mode") or a motor-connected parallel mode (equivalent to the "second mode") can be selected. The series neutral point mode is a mode in which the inter-battery switch 40 and the motor-side switch 60 are turned on and the inter-negative electrode bypass switch 50 is turned off (see Figure 4 The series neutral point mode is used, for example, when the first and second batteries 31 and 32 are externally charged by the high-voltage charger 200. The motor parallel mode is a mode in which the inter-battery switch 40 is turned off and the negative electrode bypass switch 50 and the motor side switch 60 are turned on (see Figure 7 The motor parallel mode is used, for example, when the first storage battery 31 is externally charged by the low voltage charger 210 .

[0025] The power conversion device includes a first voltage sensor 71 for detecting the voltage between the terminals of the first battery 31 and a second voltage sensor 72 for detecting the voltage between the terminals of the second battery 32. The power conversion device includes a first current sensor 73 for detecting the current flowing through the first battery 31 and a second current sensor 74 for detecting the current flowing through the second battery 32. The first current sensor 73 is provided in an electrical path connecting the positive terminal of the first battery 31 and the high potential side electrical path 22H. The second current sensor 74 is provided in an electrical path connecting the negative terminal of the second battery 32 and the low potential side electrical path 22L. The power conversion device includes a first temperature sensor 75 for detecting the temperature of the first battery 31 and a second temperature sensor 76 for detecting the temperature of the second battery 32. In addition, as other sensors, the power conversion device includes a rotation angle sensor for detecting the rotation angle (electrical angle) of the rotor and a phase current sensor for detecting the phase current flowing through the armature winding 11 of each phase.

[0026] The detection value of each sensor is input to the control device 100 (equivalent to the "control unit") included in the power conversion device. The control device 100 is mainly composed of a microcomputer 101, and the microcomputer 101 includes a CPU. The functions provided by the microcomputer 101 can be provided by software recorded in a physical memory device and a computer that executes the software, only software, only hardware, or a combination of them. For example, in the case where the microcomputer 101 is provided by an electronic circuit as hardware, it can be provided by a digital circuit or an analog circuit including a plurality of logic circuits. For example, the microcomputer 101 executes a program stored in a non-transitory tangible storage medium (non-transitory tangible storage medium) included in itself as a storage unit. The program includes, for example, the following Figure 2 The program for performing the processing shown in the above-mentioned program is executed by executing the program. The storage unit is, for example, a nonvolatile memory. In addition, the program stored in the storage unit can be updated via, for example, OTA (Over The Air) or a communication network such as the Internet.

[0027] The control device 100 performs opening and closing control of each switch SWH and SWL constituting the inverter 20 based on the detection value of each sensor, so as to feedback control the control amount of the motor 10 to a target value. The control amount is, for example, torque. In each phase, the upper arm switch SWH and the lower arm switch SWL are alternately turned on. Through this feedback control, the rotational power of the rotor is transmitted to the drive wheels of the vehicle CA, and the vehicle CA travels.

[0028] The positive electrode side connection portion of the high potential side electrical path 22H and the negative electrode side connection portion of the low potential side electrical path 22L are interfaces for connecting to an external charger. In this embodiment, the external charger is a high voltage charger 200 or a low voltage charger 210 (see Figure 4 , Figure 7 ). The charging voltage of the high-voltage charger 200 is a voltage of the same degree as the terminal voltage (specifically, the rated voltage) of the series connection of the first and second batteries 31, 32, for example, 800V. The charging voltage of the low-voltage charger 210 is a voltage lower than the rated voltage of the series connection of the first and second batteries 31, 32, for example, 400V. For example, when a user or an operator connects an external charger to each connection part and the external charger charges the first and second batteries 31, 32, the high-potential side charging switch DCRH and the low-potential side charging switch DCRL are switched on by the control device 100.

[0029] On the other hand, when charging by an external charger is not performed or when an external charger is not connected, the high potential side charging switch DCRH and the low potential side charging switch DCRL are switched off by the control device 100. When the positive electrode side connection part and the negative electrode side connection part are exposed to the outside from the housing of the power conversion device, they may touch the user or the operator. By turning off the high potential side charging switch DCRH and the low potential side charging switch DCRL, electric shock is prevented.

[0030] Next, use Figure 2 , the power transmission control process between the first and second storage batteries 31 and 32 including the charging process of the external charger is described. This process is executed by the control device 100. In addition, in this embodiment, it is assumed that Figure 2 The processing shown is executed while the vehicle CA is stopped (for example, while the vehicle is parked in a specific example).

[0031] In step S10, it is determined whether there is a power transmission request. Figure 3 As shown, when any one of the conditions (a) to (e) is satisfied, it is determined that there is a power transmission request.

[0032] (a) Condition: There is a charging request from an external charger.

[0033] When it is determined that there is a request for charging from an external charger, it is also determined whether the external charger used for charging is high-voltage charger 200 or low-voltage charger 210 .

[0034] (b) Condition: The absolute value of the difference between the voltage across the terminals of the first storage battery 31 detected by the first voltage sensor 71 (hereinafter referred to as the first detection voltage VA) and the voltage across the terminals of the second storage battery 32 detected by the second voltage sensor 72 (hereinafter referred to as the second detection voltage VB) exceeds the potential threshold value Vth.

[0035] When condition (b) is met, it is determined that there is a requirement to equalize the voltages between the terminals of the first and second batteries 31 and 32, and in step S22 described later, power is transferred between the first battery 31 and the second battery 32 to reduce the difference between the voltages between the terminals of the first battery 31 and the second battery 32. (c) Condition: The absolute value of the difference between the charge rate SOCA of the first storage battery 31 and the charge rate SOCB of the second storage battery 32 exceeds the charge threshold value Sth.

[0036] When the condition (c) is satisfied, it is determined that there is a request to equalize the charge rates (SOC: State of charge) of the first and second batteries 31 and 32, and a process is performed in step S22 etc. to transfer power between the first battery 31 and the second battery 32 to reduce the difference in charge rate between the first battery 31 and the second battery 32. In addition, for example, the first charge rate SOCA may be calculated based on the detection values ​​of the first voltage sensor 71 and the first current sensor 73, and the second charge rate SOCB may be calculated based on the detection values ​​of the second voltage sensor 72 and the second current sensor 74.

[0037] (d) Condition: The battery temperature Tbat is lower than the target temperature Tth (equivalent to the “temperature threshold”).

[0038] When the condition (d) is satisfied, it is determined that there is a request to increase the temperature of the first and second batteries 31 and 32, and in order to bring out the performance of the first and second batteries 31 and 32, a temperature increase control is performed in step S22 etc. to increase the temperature of the first and second batteries 31 and 32. The battery temperature Tbat may be, for example, the lower temperature of the temperature of the first battery 31 detected by the first temperature sensor 75 (hereinafter referred to as the first detected temperature TA) and the temperature of the second battery 32 detected by the second temperature sensor 76 (hereinafter referred to as the second detected temperature TB).

[0039] (e) Condition: There is a requirement to change the vehicle control mode.

[0040] The vehicle control mode is, for example, a parking mode or a travel preparation mode in which the inter-battery switch 40 is turned on to prepare the vehicle CA for travel. For example, when the current vehicle control mode is the parking mode and the next vehicle control mode is the travel preparation mode, before the travel preparation mode, it may be desirable to adjust the charge rate or voltage of the first and second batteries 31 and 32. In order to cope with such a situation, the condition (e) is set.

[0041] Back to previous Figure 2 In step S10, if it is determined that there is a power transmission request, the process proceeds to step S11. In step S11, information on the current vehicle control mode and information on the next vehicle control mode to be transferred after the power transmission control process is completed are acquired.

[0042] Next, in step S12, it is determined whether the operation mode of the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 can be shifted to the via-motor parallel mode. Specifically, when it is determined that the value obtained by subtracting the first detection voltage VA from the second detection voltage VB is less than the determination threshold value ΔVjde (>0), it is determined that the via-motor parallel mode can be shifted.

[0043] When the voltage between the terminals of the second battery 32 is too high relative to the voltage between the terminals of the first battery 31, when the operation mode of the inter-battery switch 40, the inter-negative bypass switch 50, and the motor-side switch 60 is switched to the motor-parallel mode, a current flows from the second battery 32 to the first battery 31 via the motor-side electrical path 25, the armature winding 11, the upper arm diode DH connected in reverse parallel to the upper arm switch SWH, and the high potential side electrical path 22H (see Figure 7 ). In this case, the reliability of the power conversion device or each storage battery 31, 32 may be reduced.

[0044] Therefore, the process of step S12 is provided to suppress the current from flowing from the second battery 32 into the first battery 31 via the motor 10 and the inverter 20 or to reduce the amount of current flowing in even if the current flows in.

[0045] In addition, the determination threshold ΔVjde can be set to, for example, when the operation mode is set to the motor parallel mode, the maximum value of the inrush current and the voltage difference between the first battery 31 and the second battery 32 whose steady-state value is less than the allowable value determined based on the relationship between "the impedance of the current path between the first battery 31 and the second battery 32 (specifically, for example, the impedance of the first and second batteries 31 and 32, the impedance of the inverter 20 and the armature winding 11, and the forward impedance of the diode of the inverter 20)" and "the voltage difference between the first battery 31 and the second battery 32". Here, the allowable value is, for example, the maximum current that the structural components on the current path can safely withstand.

[0046] In addition, the determination threshold ΔVjde is a value smaller than the rated voltage of each storage battery 31, 32. The determination threshold ΔVjde is set, for example, to a value less than 1 / 10, less than 1 / 20, less than 1 / 50, or less than 1 / 100 of the lower value of the rated voltage of each storage battery 31, 32. For example, in the following cases (1) to (3), the second detection voltage VB and the first detection voltage VA may be greatly different.

[0047] (1) In a configuration in which the rated voltages of the battery cells constituting the respective storage batteries 31 and 32 are the same, a case in which the number of battery cells constituting the first storage battery 31 is different from the number of battery cells constituting the second storage battery 32 .

[0048] (2) In a configuration where the number of battery cells constituting each of the storage batteries 31 and 32 is the same, the types of the storage batteries 31 and 32 are different and the rated voltages of the battery cells of the storage batteries 31 and 32 are different.

[0049] (3) The number of battery cells constituting each of the storage batteries 31 and 32 is different, and the types of the storage batteries 31 and 32 are different, so the rated voltages of the battery cells of the storage batteries 31 and 32 are different.

[0050] If it is determined in step S12 that the mode can be shifted to the parallel mode via the motor, the operation mode is allowed to be set to the parallel mode via the motor, and the process proceeds to step S13. In step S13, it is determined whether the external charger connected to each connection portion of each electrical path 22H, 22L is a high-voltage charger 200. If the condition (a) is satisfied in step S10 and the external charger is a high-voltage charger 200, an affirmative determination is made in step S13.

[0051] If it is determined in step S13 that the external charger is the high voltage charger 200, the process proceeds to step S14. Figure 4 As shown, the operation mode is shifted to the series neutral point mode in which the inter-battery switch 40 and the motor-side switch 60 are turned on and the inter-negative electrode bypass switch 50 is turned off.

[0052] Next, in step S15, with the main switches SMRH and SMRL and the charging switches DCRH and DCRL turned on, the high-voltage charger 200 performs a high-voltage charging mode for charging the first battery 31 and the second battery 32 based on the detection values ​​of the first and second current sensors 73 and 74 and the first and second voltage sensors 71 and 72. In this mode, Figure 4 As shown, current flows in a closed circuit including the high-voltage charger 200, the high-potential side electrical path 22H, the first battery 31, the inter-battery switch 40, the second battery 32, and the low-potential side electrical path 22L, and the first battery 31 and the second battery 32 are charged in a state of being connected in series. Figure 4 In the figure, the main switches SMRH and SMRL are omitted.

[0053] Here, in the high-voltage charging mode, the charging power of the first battery 31 and the second battery 32 can be adjusted based on the detection values ​​of the first and second current sensors 73 and 74 and the first and second voltage sensors 71 and 72. This adjustment can be implemented by opening and closing at least one phase of the inverter 20 while charging each battery 31 and 32 by the high-voltage charger 200. As an example of opening and closing, Figure 4 It is shown that for one phase, the upper arm switch SWH is turned on and the lower arm switch SWL is turned off. Figure 5 The upper arm switch SWH is turned off and the lower arm switch SWL is turned on for one phase. That is, in this switching, the upper and lower arm switches SWH and SWL of the same phase are alternately turned on.

[0054] like Figure 6 As shown in FIG. 1 , in addition to the loop LPH of the charging current of the high-voltage charger 200, current loops LPA1 and LPA2 are generated by switching. Thus, the charging power of the first battery 31 and the second battery 32 can be adjusted respectively. Here, by adjusting the ratio of the on-period Ton of the upper arm switch SWH or the lower arm switch SWL to one switching cycle Tsw, that is, the duty ratio (Ton / Tsw), the charging power of the first battery 31 and the second battery 32 can be adjusted. In this adjustment, the charging power of any of the first and second batteries 31 and 32 can also be set to zero.

[0055] For example, the charging power of the high-voltage charger 200 is set to 100 kW, and the inverter 20 is turned on and off so that 10 kW of power is continuously transmitted from the first battery 31 to the second battery 32 via the inverter 20 and the armature winding 11. Assuming that the battery characteristics, SOC, and terminal voltage of the first battery 31 and the second battery 32 are the same, the charging power of the first battery 31 is 40 kW, and the charging power of the second battery 32 is 60 kW.

[0056] When the charging power of the second battery 32 is to be greater than that of the first battery 31, the inverter 20 is opened and closed in a manner that power is transmitted from the first battery 31 to the second battery 32. Specifically, the opening and closing is performed as follows: the upper and lower arm switches SWH and SWL are alternately turned on in at least one phase, or the upper arm switch SWH of at least one phase is repeatedly turned on and off while the lower arm switches SWL of all phases are turned off.

[0057] When the charging power of the first battery 31 is to be greater than that of the second battery 32, the inverter 20 is opened and closed in a manner that power is transmitted from the second battery 32 to the first battery 31. Specifically, the upper and lower arm switches SWH and SWL are opened and closed alternately in at least one phase, or the lower arm switch SWL of at least one phase is repeatedly opened and closed while the upper arm switches SWH of all phases are opened.

[0058] In addition, when performing the above-mentioned opening and closing for separately adjusting the charging power, the opening and closing can also be performed based on the detected value of the electrical angle so that the torque of the motor 10 is zero or a value close to zero (specifically, for example, the q-axis current flowing through the armature winding 11 is zero or a value close to zero).

[0059] Being able to adjust the charging power of the first and second batteries 31 and 32 separately is advantageous when, for example, the first and second batteries 31 and 32 are made of different materials or have different charging power (eg, rated charging power).

[0060] In the high-voltage charging mode, the processing described below can be performed by opening and closing at least one phase of the inverter 20 while charging the first battery 31 and the second battery 32 by the high-voltage charger 200 .

[0061] The first process is a voltage equalization process for equalizing the first detection voltage VA and the second detection voltage VB. This process can be performed only when both conditions (a) and (b) are satisfied in step S10. In the present embodiment, each of the detection voltages VA and VB corresponds to a "capacitance parameter".

[0062] The voltage equalization process in step S15 is a process of switching the inverter 20 until the difference between the first detection voltage VA and the second detection voltage VB is equal to or less than the potential threshold value Vth, while the operation mode is set to the series neutral point mode. In this way, the voltages of the first and second batteries 31 and 32 can be equalized while the first and second batteries 31 and 32 are externally charged by the high-voltage charger 200.

[0063] The second process is a capacity equalization process that equalizes the charge rates SOCA of the first battery 31 and SOCB of the second battery 32. This process can be performed only when both conditions (a) and (c) are satisfied in step S10. In the present embodiment, the charge rates SOCA and SOCB correspond to "capacity parameters".

[0064] The capacity equalization process in step S15 is a process in which the inverter 20 is turned on and off until the difference between the charge rate SOCA of the first battery 31 and the charge rate SOCB of the second battery 32 is equal to or less than the charge threshold value Sth, while the operation mode is set to the series neutral point mode. In this way, the charge rates of the first and second batteries 31 and 32 can be equalized while the first and second batteries 31 and 32 are externally charged by the high-voltage charger 200.

[0065] In the capacity equalization process, the capacity [Ah] of the storage battery which is positively correlated with the charging rate may be used instead of the charging rate.

[0066] The third process is a temperature increase control process for increasing the temperature of the first and second storage batteries 31 and 32. This process may be executed only when both conditions (a) and (d) are satisfied in step S10.

[0067] The temperature rise control process in step S15 is to open and close the inverter 20 in a state where the operation mode is set to the series neutral point mode so that the AC charge and discharge current flows between the first battery 31 and the second battery 32 via the armature winding 11 and the inverter 20 until the battery temperature Tbat (equivalent to the "temperature parameter") reaches the target temperature Tth. The opening and closing here is to alternately turn on the upper and lower arm switches SWH and SWL in at least one phase.

[0068] The temperature increase control process can promote the heating of the battery internal resistance and increase the temperature of each battery 31, 32. This can increase the maximum charging power of each battery 31, 32 and shorten the external charging time of each battery 31, 32 while the vehicle CA is stopped.

[0069] In addition, the voltage equalization process described above may be performed before the temperature rise control process. By starting the temperature rise control process when the difference between the first detection voltage VA and the second detection voltage VB has been reduced (specifically, for example, when the difference is set to be below the potential threshold value Vth), the temperature rise rates of the batteries 31 and 32 are made as equal as possible.

[0070] That is, when the temperature increase control process is performed, the discharge power or charge power of the first storage battery 31 is equal to the charge power or discharge power of the second storage battery 32. Here, for example, the temperature increase control process is performed when the voltage between the terminals of the first storage battery 31 is 400V and the voltage between the terminals of the second storage battery 32 is 100V. In this case, based on the above-mentioned principle that the discharge power and the charge power are equal, when it is desired to repeatedly charge and discharge, for example, 40000kW of power, a charge and discharge current of a maximum of 100A flows through the first storage battery 31, and a charge and discharge current of a maximum of 400A flows through the second storage battery 32. The rate of increase in battery temperature depends on the Joule heat generated in the battery, and the Joule heat is proportional to the square of the current. Therefore, the temperature increase rate of the second storage battery 32 becomes too high compared to the temperature increase rate of the first storage battery 31. In order to avoid the occurrence of such a problem, before the temperature increase control process, a voltage equalization process is performed so that the charge and discharge currents flowing through the first and second storage batteries 31 and 32 are as equal as possible.

[0071] Incidentally, in the temperature increase control process, for example, sensor detection values ​​of the temperature of the inverter 20, the temperature of the motor 10, or the temperature of cooling water of the inverter 20 and the motor 10, which are positively correlated with the battery temperature Tbat, may be used instead of the battery temperature Tbat.

[0072] In step S15 , when individual charging power setting or voltage equalization processing is not performed, the motor-side switch 60 may be turned off. In this case, the charging current of the high-voltage charger 200 can be prevented from flowing through the inverter 20 and the armature winding 11 .

[0073] Return to Figure 2 After the processing of step S15 is completed, the process proceeds to step S16 to transfer the vehicle control mode to the next vehicle control mode.

[0074] On the other hand, if it is determined in step S13 that the external charger is not high voltage charger 200, the process proceeds to step S17 to determine whether the connected external charger is low voltage charger 210. If the condition (a) is satisfied in step S10 and the external charger is low voltage charger 210, an affirmative determination is made in step S17.

[0075] If it is determined in step S17 that the external charger is the low voltage charger 210, the process proceeds to step S18. Figure 7 As shown, the operation mode is shifted to the motor parallel mode in which the inter-battery switch 40 is turned off and the inter-negative electrode bypass switch 50 and the motor side switch 60 are turned on. At this time, the system voltage can be reduced to the same voltage as the charging voltage of the low voltage charger 210, and a ground fault countermeasure can be taken during charging by the low voltage charger 210.

[0076] Next, in step S19, with the main switches SMRH, SMRL and the charging switches DCRH, DCRL turned on, a low-voltage charging mode is performed in which the low-voltage charger 210 charges the first storage battery 31. Figure 7 As shown, current flows in a closed circuit including the low voltage charger 210 , the high potential side electrical path 22H, the first battery 31 , the negative electrode bypass switch 50 , and the low potential side electrical path 22L, and the first battery 31 is charged by the low voltage charger 210 .

[0077] Here, in the low voltage charging mode, the charging power of the first battery 31 and the second battery 32 can be adjusted based on the detection values ​​of the first and second current sensors 73 and 74 and the first and second voltage sensors 71 and 72. This adjustment can be implemented by repeatedly turning on and off the upper arm switch SWH of at least one phase in the inverter 20 while charging the first battery 31 by the low voltage charger 210. As an example of opening and closing, Figure 7 It is shown that for one phase, the upper arm switch SWH is turned on and the lower arm switch SWL is turned off, Figure 8It is shown that for one phase, the upper arm switch SWH is turned off and the lower arm switch SWL is turned on. In addition, in this adjustment, the charging power of any one of the first and second storage batteries 31 and 32 can also be set to zero.

[0078] like Fig. 9 As shown in FIG. 1 , in addition to the loop LPL of the charging current of the low voltage charger 210, a current loop LPB is generated by switching. Thus, the charging power of the first battery 31 and the second battery 32 can be adjusted respectively. Here, by adjusting the ratio of the on period Ton of the upper arm switch SWH to one switching cycle Tsw, that is, the duty ratio (Ton / Tsw), the charging power of the first battery 31 and the second battery 32 can be adjusted.

[0079] Even in the low voltage charging mode, the first battery 31 is charged by the low voltage charger 210 , while at least one phase of the inverter 20 is switched on and off to perform voltage equalization, capacity equalization, and temperature increase control.

[0080] The voltage equalization process in step S19 is a process of opening and closing the inverter 20 until the difference between the first detection voltage VA and the second detection voltage VB is equal to or less than the potential threshold value Vth, while the operation mode is set to the motor parallel mode. In this way, while the first battery 31 is externally charged by the low voltage charger 210, power is supplied from the first battery 31 to the second battery 32 via the inverter 20 and the armature winding 11, thereby equalizing the voltages of the first and second batteries 31 and 32.

[0081] The capacity equalization process in step S19 is a process of opening and closing the inverter 20 until the difference between the charge rate SOCA of the first battery 31 and the charge rate SOCB of the second battery 32 is equal to or less than the charge threshold value Sth while the operation mode is set to the motor parallel mode. In this way, the charge rates of the first and second batteries 31 and 32 can be equalized while the first battery 31 is externally charged by the low voltage charger 210.

[0082] The temperature rise control process in step S19 is to open and close the inverter 20 in such a way that the AC charge and discharge current flows between the first battery 31 and the second battery 32 via the armature winding 11 and the inverter 20, while the operation mode is set to the motor parallel mode, until the battery temperature Tbat reaches the target temperature Tth. In addition, the above-mentioned voltage equalization process may also be performed before the temperature rise control process.

[0083] According to the low voltage charging mode, the first battery 31 can be directly charged by the low voltage charger 210, and the second battery 32 can be charged via the inverter 20 and the armature winding 11. In addition, even when the rated voltages of the first and second batteries 31 and 32 are different, or when the rated voltages are the same but the actual terminal voltages of the first and second batteries 31 and 32 are different, the first and second batteries 31 and 32 can be charged simultaneously without an additional power conversion circuit.

[0084] Return to Figure 2 As explained above, after the processing of step S19 is completed, the process proceeds to step S16 to transfer the vehicle control mode to the next vehicle control mode.

[0085] If a negative determination is made in step S17, the process proceeds to step S20. If the condition (a) is not satisfied in step S10 and at least one of the conditions (b) to (e) is satisfied, a negative determination is made in step S17.

[0086] In step S20, it is determined whether the operation mode selected when the power transmission control is performed in step S22 is the series neutral point mode or the motor parallel mode. Here, the total number of opening and closing times of the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor side switch 60 from the current vehicle control mode to the next vehicle control mode via the power transmission control in step S22 is determined by which of the cases where the series neutral point mode is selected and the case where the motor parallel mode is selected in the power transmission control is smaller.

[0087] Specifically, the first total number of opening and closing times of the inter-battery switch 40 , the inter-negative electrode bypass switch 50 , and the motor-side switch 60 when the current vehicle control mode is shifted to the next vehicle control mode via the power transmission control in which the series neutral point mode is selected is calculated.

[0088] Furthermore, the second total opening and closing times of the inter-battery switch 40 , the inter-negative electrode bypass switch 50 , and the motor-side switch 60 when the current vehicle control mode is shifted to the next vehicle control mode via the power transmission control selected via the motor parallel mode are calculated.

[0089] When the first total switching frequency is less than the second total switching frequency, the process proceeds to step S23 to select the series neutral point mode. On the other hand, when the second total switching frequency is less than the first total switching frequency, the process proceeds to step S21 to select the motor-connected parallel mode.

[0090] According to the process of step S20 , it is possible to suppress the progress of the deterioration of the inter-battery switch 40 , the inter-negative electrode bypass switch 50 , and the motor-side switch 60 .

[0091] In step S20, the total number of opening and closing of the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 when the current vehicle control mode is shifted to the power transmission control selected as the series neutral point mode may be calculated as the first total number of opening and closing. In step S20, the total number of opening and closing of the inter-battery switch 40, the inter-negative electrode bypass switch 50, and the motor-side switch 60 when the current vehicle control mode is shifted to the power transmission control selected as the parallel motor mode may be calculated as the second total number of opening and closing.

[0092] If the motor parallel mode is selected in step S20, the process proceeds to step S21, the operation mode is set to the motor parallel mode, and the voltage equalization process, capacity equalization process or temperature rise control process described above is performed in step S22. Thereafter, the process proceeds to step S16.

[0093] On the other hand, if the series neutral point mode is selected in step S20, the process proceeds to step S23, the operation mode is set to the series neutral point mode, and voltage equalization processing, capacity equalization processing or temperature rise control processing is performed in step S22. Thereafter, the process proceeds to step S16.

[0094] If it is determined in step S12 that the mode cannot be transferred to the parallel mode via the motor, it is prohibited to set the operation mode to the parallel mode via the motor, and the process proceeds to step S24. In step S24, it is determined whether the external charger connected to each connection portion of each electrical path 22H, 22L is a low-voltage charger 210. In step S10, if condition (a) is not satisfied and at least one of (b) to (e) is satisfied, a negative determination is made in step S24, and the process proceeds to step S23. Then, in the state where the operation mode is set to the series neutral point mode, voltage equalization processing, capacity equalization processing, or temperature rise control processing is performed in step S22.

[0095] If an affirmative determination is made in step S24 , after the operation mode is set to a state capable of shifting to the motor parallel mode, the low voltage charging mode of step S19 is performed.

[0096] Specifically, first, in step S25, each of the charging switches DCRH and DCRL is turned off, thereby electrically disconnecting the power conversion device from the external charger, thereby ensuring the safety of the user or operator of the vehicle CA.

[0097] Next, in step S26, the operation mode is set to the series neutral point mode. In step S27, the upper arm switch SWH of at least one phase is repeatedly turned on and off under the condition that the upper and lower arm switches SWH and SWL of the same phase are not turned on at the same time, thereby transmitting power from the first battery 31 to the second battery 32 until the difference between the first detection voltage VA and the second detection voltage VB is less than the potential threshold Vth. Then, when it is determined that the difference between the first detection voltage VA and the second detection voltage VB is less than the potential threshold, the process proceeds to step S18, the operation mode is switched to the parallel mode via the motor, and the low voltage charging mode is performed in step S19.

[0098] According to the present embodiment described above, it is possible to provide a power conversion device having a simplified structure for appropriately charging the first and second storage batteries 31 and 32 .

[0099] <Second embodiment> Hereinafter, the second embodiment will be described with reference to the accompanying drawings, focusing on the differences from the first embodiment. In this embodiment, in the power transmission control process, the switching control of the inverter 20 is performed. At this time, a high-frequency current is generated accompanying the switching. In this embodiment, as shown in FIG. Fig.10 As shown, the power conversion device includes a capacitor 90 that suppresses high-frequency current generated by switching from the inverter 20 side to flow into the second storage battery 32 and the low-voltage charger 210 .

[0100] The portion between the low potential side main switch SMRL and the low potential side charging switch DCRL in the low potential side electrical path 22L is connected to a position closer to the neutral point side than the motor side switch 60 in the motor side electrical path 25 via a series connection body of a connecting switch 91 and a capacitor 90. The connecting switch 91 may be a mechanical relay or a semiconductor switching element.

[0101] The control device 100 opens the connection switch 91 during the on / off control of the inverter 20 for driving the vehicle CA. Thus, when the control amount of the electric motor 10 is controlled to be the command value, it is possible to suppress adverse effects on the control.

[0102] On the other hand, the control device 100 is, for example, Figure 2 In the process shown, the connection switch 91 is turned on. Thus, when current flows through the motor-side electric path 25 , noise or ripple included in the current flowing through the motor-side electric path 25 can be made to flow through the capacitor 90 .

[0103] According to the present embodiment described above, during the power transmission control process, it is possible to suppress the high-frequency current generated by switching from the inverter 20 side from flowing into the second battery 32 and the low-voltage charger 210 .

[0104] <Modification of Second Embodiment> The capacitor 90 may be connected to the motor-side electric path 25 side, and the connection switch 91 may be connected to the low-potential-side electric path 22L side.

[0105] The connection switch 91 may not be provided. That is, the motor-side electric path 25 and the low-potential-side electric path 22L may be always connected.

[0106] ·like Fig.11 As shown, the series connection body of the connection switch 92 and the capacitor 90 may connect a portion of the motor-side electric path 25 closer to the second battery 32 than the motor-side switch 60 to the low potential-side electric path 22L.

[0107] In addition, Fig.11 In the illustrated structure, the connection switch 92 may not be provided. That is, the motor-side electric path 25 and the low-potential-side electric path 22L may be always connected.

[0108] ·like Fig.12 As shown, a plurality of capacitors may be provided. Specifically, a connection switch 93 is provided at a position closer to the neutral point than the motor-side switch 60 in the motor-side electrical path 25. In the portion between the motor-side switch 60 and the connection switch 93 in the motor-side electrical path 25, a high potential side electrical path 22H is connected via a first capacitor 93A, and a low potential side electrical path 22L is also connected via a second capacitor 93B.

[0109] In addition, Fig.12 In the illustrated structure, either the first capacitor 93A or the second capacitor 93B may be omitted.

[0110] ·like Fig.13 As shown, the first end of the connection switch 94 may be connected to a position closer to the neutral point than the motor-side switch 60 in the motor-side electric path 25 , and the second end of the connection switch 94 may be connected to the first capacitor 93A and the second capacitor 93B.

[0111] <Third Embodiment> Hereinafter, referring to the accompanying drawings, the third embodiment will be described with a focus on the differences from the second embodiment. Fig.14 As shown in FIG. 1 , the series connection of the precharge switch SP and the resistor 95 is connected in parallel with the low potential side main switch SMRL. Fig.14 In the figure, illustration of the control device 100 and the like is omitted for convenience.

[0112] The power conversion device includes a third voltage sensor 77A that detects a voltage between terminals of capacitor 90 and a fourth voltage sensor 77B that detects a voltage between terminals of smoothing capacitor 21. Detection values ​​of third voltage sensor 77A and fourth voltage sensor 77B are input to control device 100.

[0113] Then use Figure 15 to Figure 17 , including the abnormal diagnosis of each switch in the series neutral point mode (such as welding diagnosis), the economic opening and closing sequence of each switch is explained. Figure 15 to Figure 17 In FIG. 1 , Vcinv represents the voltage between the terminals of the smoothing capacitor 21 detected by the fourth voltage sensor 77B, and Vcb represents the voltage between the terminals of the capacitor 90 detected by the third voltage sensor 77A. Figure 15 to Figure 17 The timing diagrams of the voltages Vcinv and Vcb shown are diagrams when no failure of the switches occurs. Figure 15 to Figure 17 The shaded period shown indicates an executable period of abnormality diagnosis.

[0114] exist Figure 15 to Figure 17 In the description, the operation of turning on the switch is referred to as the on-operation of the switch, and the state in which the switch is actually turned on by the on-operation is referred to as the on-state of the switch. In addition, the operation of turning off the switch is referred to as the off-operation of the switch, and the state in which the switch is actually turned off by the off-operation is referred to as the off-state of the switch. A failure in which the switch remains in the off state even after the on-operation is referred to as the on-failure of the switch, and a failure in which the switch remains in the on state even after the off-operation is referred to as the off-failure of the switch. In addition to the abnormality of the switch itself, the on and off failures of the switch may also be caused by, for example, abnormalities in the drive circuit of the switch.

[0115] First of all, Fig.15 Provide explanation.

[0116] At time t1 , the main switches SWRH and SWRL, the precharge switch SP, the inter-battery switch 40 , the inter-negative electrode bypass switch 50 , the motor-side switch 60 , and the connection switch 93 are turned off.

[0117] At time t2, the control device 100 switches the precharge switch SP to the on operation. During the period from time t2 to t3, the control device 100 determines whether the closing fault of the motor side switch 60 has occurred based on the inter-terminal voltage Vcb of the capacitor 90. Specifically, when the control device 100 determines that the inter-terminal voltage Vcb of the capacitor 90 has not increased, it determines that the closing fault of the motor side switch 60 has not occurred, and when it determines that the inter-terminal voltage Vcb of the capacitor 90 has increased, it determines that the closing fault of the motor side switch 60 has occurred.

[0118] At time t3, the control device 100 switches the high potential side main switch SMRH to the on operation. During the period from time t3 to time t4, the control device 100 determines whether the closing fault of the inter-battery switch 40 and the inter-negative bypass switch 50 has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21. Specifically, when the control device 100 determines that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has not increased, it determines that the closing fault of the inter-battery switch 40 and the inter-negative bypass switch 50 has not occurred, and when it determines that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has increased, it determines that the closing fault of the inter-battery switch 40 and the inter-negative bypass switch 50 has occurred.

[0119] At time t4, the control device 100 switches the connection switch 93 to the on state.

[0120] At time t5 , the control device 100 switches the motor side switch 60 to the on operation. If there is no abnormality in each switch, the voltage between the terminals of the capacitor 90 and the smoothing capacitor 21 rises to the voltage VB between the terminals of the second battery 32 .

[0121] The control device 100 determines whether the open fault of the motor side switch 60 has occurred based on the inter-terminal voltage Vcb of the capacitor 90 during the period from time t5 to time t6. Specifically, the control device 100 determines that the open fault of the motor side switch 60 has not occurred when it is determined that the inter-terminal voltage Vcb of the capacitor 90 has increased, and determines that the open fault of the motor side switch 60 has occurred when it is determined that the inter-terminal voltage Vcb of the capacitor 90 has not increased.

[0122] The control device 100 determines whether an open fault of the connection switch 93 has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 during the period from time t5 to time t6. Specifically, the control device 100 determines that the open fault of the connection switch 93 has not occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has increased, and determines that the open fault of the connection switch 93 has occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has not increased.

[0123] The control device 100 determines whether the shutdown fault of the low potential side main switch SMRL has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 and the determination voltage of at least one of the capacitor 90 during the period from time t5 to time t6. Specifically, when the control device 100 determines that the rising speed of the determination voltage is equal to the rising speed of the determination voltage when the low potential side main switch SMRL is in the disconnected state, it determines that the shutdown fault of the low potential side main switch SMRL has not occurred. On the other hand, when the control device 100 determines that the rising speed of the determination voltage is higher than the rising speed of the determination voltage when the low potential side main switch SMRL is in the disconnected state, it determines that the shutdown fault of the low potential side main switch SMRL has occurred.

[0124] The control device 100 determines whether the open fault of the precharge switch SP has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 and the determination voltage of at least one of the capacitor 90 during the period from time t5 to time t6. Specifically, the control device 100 determines that the open fault of the precharge switch SP has not occurred when it is determined that the determination voltage has increased, and determines that the open fault of the precharge switch SP has occurred when it is determined that the determination voltage has not increased.

[0125] At time t6, the control device 100 switches the inter-battery switch 40 to the on state. If there is no abnormality in the switches, the inter-terminal voltage of the smoothing capacitor 21 rises to the sum of the inter-terminal voltages of the first and second batteries 31 and 32, VA+VB. Thus, precharging is completed.

[0126] The control device 100 determines whether the open fault of the high potential side main switch SMRH and the inter-battery switch 40 has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 during the period from time t6 to time t7. Specifically, the control device 100 determines that the open fault of the high potential side main switch SMRH and the inter-battery switch 40 has not occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has increased, and determines that the open fault of the high potential side main switch SMRH and the inter-battery switch 40 has occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has not increased.

[0127] At time t7 , the control device 100 switches the low potential side main switch SMRL to an on operation.

[0128] At time t8, the control device 100 switches the precharge switch SP to an OFF state, thereby completing the startup sequence.

[0129] During the period from time t8 to time t9, the control device 100 performs Figure 2During the period from time t8 to time t9, the control device 100 determines whether an expected current flows based on at least one detection value of a current sensor included in the power conversion device, thereby determining whether an open fault of the low potential side main switch SMRL occurs.

[0130] At time t9 , the control device 100 switches the high potential side main switch SMRH to an OFF operation to start the end sequence.

[0131] At time t10, the control device 100 switches the motor side switch 60 to an OFF operation. The control device 100 repeatedly turns on and off the lower arm switch SWL of at least one phase to transfer charge from the capacitor 90 to the smoothing capacitor 21, thereby completing the discharge of the capacitor 90.

[0132] At time t11, the control device 100 switches the connection switch 93 to an OFF operation. The control device 100 releases the charge from the smoothing capacitor 21 by opening and closing the upper and lower arm switches SWH and SWL, and completes the discharge of the smoothing capacitor 21. At time t12, the control device 100 switches the low potential side main switch SMRL and the inter-battery switch 40 to an OFF operation. Thereafter, the end sequence ends at time t13.

[0133] The control device 100 determines whether the closing fault of the high potential side main switch SMRH and the pre-charge switch SP has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 during the period from time t11 to time t12. Specifically, the control device 100 determines that the closing fault of the high potential side main switch SMRH and the pre-charge switch SP has not occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has decreased, and determines that the closing fault of the high potential side main switch SMRH and the pre-charge switch SP has occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has not decreased.

[0134] In addition, the control device 100 may also perform opening and closing control of the inverter 20 in a manner that supplies power from the smoothing capacitor 21 to the capacitor 90 during the discharge period of the smoothing capacitor 21 starting from time t11 or before the discharge thereof, and when it is determined that the voltage Vcb between the terminals of the capacitor 90 does not rise during the opening and closing control period, it is determined that an opening fault of the connecting switch 93 has occurred.

[0135] The control device 100 determines whether a closing fault of the connection switch 93 has occurred based on the voltage Vcb between the terminals of the capacitor 90 during the period from time t11 to time t12. Specifically, the control device 100 determines that a closing fault of the connection switch 93 has not occurred when it is determined that the voltage Vcb between the terminals of the capacitor 90 has not increased, and determines that a closing fault of the connection switch 93 has occurred when it is determined that the voltage Vcb between the terminals of the capacitor 90 has increased.

[0136] Incidentally, in the series neutral point mode, the negative electrode bypass switch 50 is assumed to be in the open state. Therefore, in the present embodiment, the presence or absence of an open failure of the negative electrode bypass switch 50 is not diagnosed.

[0137] Next, Fig.16 Provide explanation.

[0138] At time t1 , the main switches SWRH and SWRL, the precharge switch SP, the inter-battery switch 40 , the inter-negative electrode bypass switch 50 , the motor-side switch 60 , and the connection switch 93 are turned off.

[0139] At time t2, the control device 100 switches the precharge switch SP to an on operation. During the period from time t2 to time t3, the control device 100 and the Fig.15 Similarly, during the period from time t2 to time t3 , it is determined whether or not a closing failure of the motor-side switch 60 has occurred based on the inter-terminal voltage Vcb of the capacitor 90 .

[0140] At time t3, the control device 100 switches the high potential side main switch SMRH to the on operation. During the period from time t3 to time t4, the control device 100 and Fig.15 Similarly, during the period from time t3 to time t4, it is determined whether or not a closing failure of the inter-battery switch 40 and the inter-negative electrode bypass switch 50 has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21.

[0141] At time t4, the control device 100 switches the inter-battery switch 40 to the on state. If there is no abnormality in the switches, the inter-terminal voltage of the smoothing capacitor 21 rises to the sum of the inter-terminal voltages of the first and second batteries 31 and 32, VA+VB. Thus, the pre-charging of the smoothing capacitor 21 is completed.

[0142] The control device 100 determines whether an open fault of the high potential side main switch SMRH, the precharge switch SP, and the inter-battery switch 40 has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 during the period from time t4 to time t5. Specifically, the control device 100 determines that the open fault of the high potential side main switch SMRH, the precharge switch SP, and the inter-battery switch 40 has not occurred when it is determined that the inter-terminal voltage Vcinv of the smoothing capacitor 21 has increased, and determines that at least one of the high potential side main switch SMRH, the precharge switch SP, and the inter-battery switch 40 has an open fault when it is determined that the inter-terminal voltage Vcinv has not increased.

[0143] The control device 100 determines whether the shutdown fault of the low potential side main switch SMRL has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21 during the period from time t4 to time t5. Specifically, the control device 100 determines that the shutdown fault of the low potential side main switch SMRL has not occurred when it is determined that the rising speed of the inter-terminal voltage Vcinv is equal to the rising speed of the inter-terminal voltage Vcinv when the low potential side main switch SMRL is in the disconnected state. On the other hand, the control device 100 determines that the shutdown fault of the low potential side main switch SMRL has occurred when it is determined that the rising speed of the inter-terminal voltage Vcinv is higher than the rising speed of the inter-terminal voltage Vcinv when the low potential side main switch SMRL is in the disconnected state.

[0144] At time t5, the control device 100 switches the connection switch 93 to on operation. At time t6, the control device 100 switches the motor side switch 60 to on operation. When there is no abnormality in each switch, the inter-terminal voltage Vcb of the capacitor 90 rises to the inter-terminal voltage VB of the second battery 32 .

[0145] During the period from time t5 to time t6, the control device 100 and Fig.15 Similarly, during the period from time t5 to time t6 , it is determined whether an open failure of the motor-side switch 60 has occurred based on the inter-terminal voltage Vcb of the capacitor 90 .

[0146] At time t7, the control device 100 switches the low potential side main switch SMRL to an on operation. At time t8, the control device 100 switches the precharge switch SP to an off operation. Thus, the start sequence ends.

[0147] During the period from time t8 to time t9, the control device 100 performs Figure 2 The control device 100 determines whether an expected current flows based on at least one detection value of a current sensor included in the power conversion device during the period from time t8 to time t9, thereby determining whether an open fault of the low potential side main switch SMRL and the connection switch 93 occurs.

[0148] At time t9 , the control device 100 switches the high potential side main switch SMRH to an OFF operation to start the end sequence.

[0149] At time t10, the control device 100 switches the motor side switch 60 to an OFF operation. The control device 100 repeatedly turns on and off the lower arm switch SWL of at least one phase to transfer charge from the capacitor 90 to the smoothing capacitor 21, thereby completing the discharge of the capacitor 90.

[0150] At time t11, the control device 100 switches the connection switch 93 to an OFF operation. The control device 100 discharges the charge from the smoothing capacitor 21 by opening and closing the upper and lower arm switches SWH and SWL, and completes the discharge of the smoothing capacitor 21. At time t12, the control device 100 switches the low potential side main switch SMRL and the inter-battery switch 40 to an OFF operation. Thereafter, the end sequence ends at time t13.

[0151] During the period from time t11 to time t12, the control device 100 and Fig.15 Similarly, during the period from time t11 to t12, based on the inter-terminal voltage Vcinv of the smoothing capacitor 21, it is determined whether a closing fault of the high potential side main switch SMRH has occurred, and based on the inter-terminal voltage Vcb of the capacitor 90, it is determined whether a closing fault of the connection switch 93 has occurred.

[0152] In addition, the control device 100 may also be Fig.15 Similarly, during the discharge period of the smoothing capacitor 21 starting from time t11 or before its discharge, the opening and closing control of the inverter 20 is performed in a manner that supplies power from the smoothing capacitor 21 to the capacitor 90, and when it is determined that the terminal voltage Vcb of the capacitor 90 does not rise during the opening and closing control period, it is determined that an opening fault of the connection switch 93 has occurred.

[0153] Next, Fig.17 Provide explanation.

[0154] The processing during time t1 to t5 is Fig.16 The processing during the period from time t1 to time t5 is the same.

[0155] The control device 100 performs a process of charging the capacitor 90 by the on / off control of the inverter 20 during the period from time t5 to t7. Here, the on / off control is stopped before the inter-terminal voltage Vcb of the capacitor 90 reaches the inter-terminal voltage VB of the second storage battery 32. During the period from time t5 to t6, the control device 100 determines that the closing fault of the connection switch 93 has not occurred when it is determined that the inter-terminal voltage Vcinv of the capacitor 90 has not increased, and determines that the closing fault of the connection switch 93 has occurred when it is determined that the inter-terminal voltage Vcinv has increased.

[0156] At time t7, the control device 100 switches the motor-side switch 60 to the on state. That is, the first half of the pre-charging of the capacitor 90 is performed by supplying electric charge from the smoothing capacitor 21 by the opening and closing of the inverter 20 .

[0157] During the period from time t7 to time t8, the control device 100 and Fig.16Similarly, during the period from time t6 to time t7, it is determined whether an open failure of the motor-side switch 60 has occurred based on the inter-terminal voltage Vcb of the capacitor 90.

[0158] At time t8, the control device 100 switches the low potential side main switch SMRL to an on operation. At time t9, the control device 100 switches the precharge switch SP to an off operation. Thus, the start sequence ends.

[0159] During the period from time t9 to time t10, the control device 100 performs Figure 2 During the period from time t9 to time t10, the control device 100 performs the following operations with Fig.16 Similarly, during the period from time t8 to time t9, it is determined whether an open failure of the low potential side main switch SMRL occurs.

[0160] At time t10 , the control device 100 switches the high potential side main switch SMRH to an OFF operation to start the end sequence.

[0161] At time t11, the control device 100 switches the motor side switch 60 to an OFF operation. The control device 100 repeatedly performs on-off control of the lower arm switch SWL of at least one phase to transfer charge from the capacitor 90 to the smoothing capacitor 21, thereby completing the discharge of the capacitor 90.

[0162] At time t12, the control device 100 switches the connection switch 93 to an OFF operation. The control device 100 releases the charge from the smoothing capacitor 21 by opening and closing the upper and lower arm switches SWH and SWL, and completes the discharge of the smoothing capacitor 21. At time t13, the control device 100 switches the low potential side main switch SMRL and the inter-battery switch 40 to an OFF operation. Thereafter, the end sequence ends at time t14.

[0163] During the period from time t12 to time t13, the control device 100 Fig.16 Similarly, during the period from time t11 to time t12, it is determined whether or not a turn-off failure of the high potential side main switch SMRH has occurred based on the inter-terminal voltage Vcinv of the smoothing capacitor 21.

[0164] <Modification of the third embodiment> ·like Fig.18 As shown, a series connection body of the precharge switch SP and the resistor 95 may be connected in parallel with the motor side switch 60 .

[0165] For example, when the power converter is started, the control device 100 performs a precharge process to charge the smoothing capacitor 21. In the present embodiment, even if either the first battery 31 or the second battery 32 fails and cannot be used, the remaining battery can be used for precharge process.

[0166] First, use Fig.19 The case where an abnormality occurs in the second storage battery 32 will be described. In this case, the control device 100 turns on the high potential side main switch SMRH, the precharge switch SP, and the inter-battery switch 40, and turns off the low potential side main switch SMRL, the motor side switch 60, and the negative electrode bypass switch 50. In addition, the control device 100 turns off the upper and lower arm switches SWH and SWL of all phases of the inverter 20. As a result, the smoothing capacitor 21 can be charged by the first storage battery 31.

[0167] Next, use Fig. 20 The case where an abnormality occurs in the first storage battery 31 will be described. In this case, the control device 100 turns on the low potential side main switch SMRL and the precharge switch SP, and turns off the high potential side main switch SMRH, the motor side switch 60, the inter-battery switch 40, and the inter-negative electrode bypass switch 50. In addition, the control device 100 turns off the upper and lower arm switches SWH and SWL of all phases of the inverter 20. As a result, the smoothing capacitor 21 can be charged by the second storage battery 32.

[0168] ·like Fig.21 As shown, in Fig. 20 In the structure shown in FIG. 1 , a connection switch 93 and a capacitor 90 may also be provided. In the pre-charging process for charging the smoothing capacitor 21, the control device 100 can charge the smoothing capacitor 21 and the capacitor 90 at the same time. Fig. 22 As shown, the control device 100 turns on the high potential side main switch SMRH, the precharge switch SP and the inter-battery switch 40, and turns off the low potential side main switch SMRL, the motor side switch 60 and the inter-negative bypass switch 50. In addition, the control device 100 turns off the upper and lower arm switches SWH and SWL of all phases of the inverter 20.

[0169] <Fourth embodiment> Hereinafter, referring to the accompanying drawings, the fourth embodiment will be described with a focus on the differences from the first embodiment. Fig.23 As shown, the power conversion device further includes a positive electrode bypass switch 51 that connects the positive electrode terminal of the second storage battery 32 and the high potential side electrical path 22H.

[0170] The control device 100 can charge the second storage battery 32 alone by the low voltage charger 210 , for example, in a state where the positive electrode bypass switch 51 is turned on and the negative electrode bypass switch 50 , the battery switch 40 , and the motor-side switch 60 are turned off.

[0171] In addition, the control device 100 performs the previous Figure 2 When processing, just disconnect the positive electrode bypass switch 51.

[0172] <Fifth embodiment> Hereinafter, referring to the accompanying drawings, the fifth embodiment will be described with a focus on the differences from the first embodiment. Fig.24 As shown, the power conversion device includes a positive electrode bypass switch 51, excluding the previous Figure 1 The negative electrode bypass switch 50 is shown. The motor side electric path 25 connects the neutral point of the armature winding 11 to a portion of the inter-battery electric path 24 closer to the first battery 31 than the inter-battery switch 40. The motor side switch 61 is provided on the motor side electric path 25.

[0173] In this embodiment, the series neutral point mode is a mode in which the inter-battery switch 40 and the motor-side switch 61 are turned on and the positive electrode bypass switch 51 is turned off (see Fig.25 The motor parallel connection mode is a mode in which the inter-battery switch 40 is turned off and the positive electrode bypass switch 51 and the motor side switch 61 are turned on (refer to Fig.26 ).

[0174] Next, refer to the previous Figure 2 The power transmission control process of this embodiment will be described. Hereinafter, the changes from the first embodiment will be mainly described.

[0175] In step S12, when it is determined that the value obtained by subtracting the second detection voltage VB from the first detection voltage VA is less than the determination threshold value ΔVjde, it is determined that the mode can be transferred to the parallel mode via the motor, and when it is determined that the value after the subtraction exceeds the determination threshold value ΔVjde, it is determined that the mode cannot be transferred to the parallel mode via the motor. When the voltage between the terminals of the first battery 31 is too high relative to the voltage between the terminals of the second battery 32 and the operation mode of the inter-battery switch 40, the positive electrode bypass switch 51, and the motor side switch 61 is switched to the parallel mode via the motor, a closed circuit including the high potential side electrical path 22H, the positive electrode bypass switch 51, the second battery 32, the low potential side electrical path 22L, the lower arm diode DL connected in reverse parallel to the lower arm switch SWL, the armature winding 11, and the motor side switch 61 is formed from the first battery 31, and a phenomenon occurs in which current flows from the first battery 31 to the second battery 32.

[0176] When entering step S19 through steps S17 and S18, the low voltage charging mode is performed in which the low voltage charger 210 charges the second battery 32 while the main switches SMRH and SMRL and the charging switches DCRH and DCRL are turned on. Fig.26As shown, current flows in a closed circuit including the low voltage charger 210 , the high potential side electrical path 22H, the positive electrode bypass switch 51 , the second battery 32 and the low potential side electrical path 22L, and the second battery 32 is charged by the low voltage charger 210 .

[0177] Here, in the low voltage charging mode, the charging power of the first battery 31 and the second battery 32 can be adjusted separately. This adjustment can be implemented by repeatedly turning on and off the lower arm switch SWL of at least one phase in the inverter 20 while charging the first battery 31 by the low voltage charger 210. Here, by adjusting the ratio of the on period Ton of the lower arm switch SWL to one opening and closing cycle Tsw, that is, the duty ratio (Ton / Tsw), the charging power of the first battery 31 and the second battery 32 can be adjusted.

[0178] Even in the low voltage charging mode, the second battery 32 can be charged by the low voltage charger 210 while voltage equalization, capacity equalization, and temperature increase control can be performed by switching at least one phase of the inverter 20 .

[0179] In step S27, the lower arm switch SWL of at least one phase is repeatedly turned on and off under the condition that the upper and lower arm switches SWH and SWL of the same phase are not turned on at the same time, thereby transmitting power from the second battery 32 to the first battery 31 until the difference between the first detection voltage VA and the second detection voltage VB is less than the potential threshold value Vth. Then, when it is determined that the difference between the first detection voltage VA and the second detection voltage VB is less than the potential threshold value, the process proceeds to step S18, the operation mode is switched to the parallel mode via the motor, and the low voltage charging mode is performed in step S19.

[0180] According to the present embodiment described above, the same effects as those of the first embodiment can be achieved.

[0181] <Sixth embodiment> Hereinafter, referring to the accompanying drawings, the sixth embodiment will be described with a focus on the differences from the fifth embodiment. Fig. 27 As shown, the power conversion device includes a positive electrode bypass switch 51 in addition to the negative electrode bypass switch 50 .

[0182] The control device 100 can charge the first storage battery 31 alone by the low voltage charger 210 , for example, in a state where the inter-negative electrode bypass switch 50 is turned on and the inter-positive electrode bypass switch 51 , the inter-battery switch 40 , and the motor-side switch 61 are turned off.

[0183] In addition, the control device 100 performs the previous Figure 2When processing, just open the negative electrode bypass switch 50.

[0184] <Seventh embodiment> Hereinafter, referring to the accompanying drawings, the seventh embodiment will be described with a focus on the differences from the above-mentioned embodiments. Fig.28 As shown, as the motor side switch, in addition to the switch connecting the neutral point of the armature winding 11 and the negative terminal of the first battery 31, a switch connecting the neutral point of the armature winding 11 and the positive terminal of the second battery 32 is included.

[0185] The neutral point of the armature winding 11 is connected to the first end of the common path 26. The second end of the common path 26 is connected to the first end of the first electrical path 27, and the second end of the first electrical path 27 is connected to a position in the inter-battery electrical path 24 that is closer to the second battery 32 than the inter-battery switch 40. In addition, the second end of the common path 26 is connected to the first end of the second electrical path 28, and the second end of the second electrical path 28 is connected to a position in the inter-battery electrical path 24 that is closer to the first battery 31 than the inter-battery switch 40. A first motor side switch 60 is provided in the first electrical path 27. A second motor side switch 61 is provided in the second electrical path 28. In addition, the common path 26 may not be provided, and the first ends of the first electrical path 27 and the second electrical path 28 may be connected to the neutral point of the armature winding 11.

[0186] According to the present embodiment described above, Figure 1 The circuit structure shown in Figure 2 The processing can also be Fig.24 The circuit structure shown in Figure 2 processing.

[0187] <Other embodiments> In addition, each of the above-mentioned embodiments may be implemented with the following modifications.

[0188] ·like Fig.29As shown, a third current sensor 78 may be provided at a portion between a connection point with the first battery 31 and a high potential side charging switch DCRH in the high potential side electrical path 22H. In addition, a fourth current sensor 79 may be provided at any position in the motor side electrical path 25. For example, the fourth current sensor 79 may be provided at a position closer to the neutral point than the motor side switch 60 in the motor side electrical path 25. Here, at least two current sensors among the first to fourth current sensors 73, 74, 78, and 79 may be provided. Thus, the charging control of each battery 31, 32 may be realized by as few current sensors as possible. In addition, a current sensor for detecting the current flowing through each conductive member 23 may be provided, and the detection value of the fourth current sensor may be replaced by the total value of the current detection value flowing through each conductive member 23.

[0189] The connection point of the motor side electric path 25 is not limited to the neutral point of the armature winding 11, for example Fig.30 As shown, it may be the middle part of the armature winding 11 .

[0190] In addition, the connection of the motor side electric path 25 is as follows, for example Fig.31 As shown, it can also be a conductive member 23. At this time, Fig.32 As shown in the previous Figure 2 The opening and closing of the inverter 20 in steps S15, S19, and S22 can be performed as follows: in each phase, the upper and lower arm switches SWH and SWL of the phase connecting the motor side electrical path 25 and the conductive component 23 are disconnected, and the upper and lower arm switches SWH and SWL of at least one phase other than the phase connecting the motor side electrical path 25 and the conductive component 23 are alternately connected.

[0191] ·You can also Fig.33 As shown, a high potential side charging switch DCRH and a positive side connecting portion are provided on the side of the high potential side electrical path 22H opposite to the inverter 20 and the first battery 31 side, and a low potential side charging switch DCRL and a negative side connecting portion are provided on the side of the low potential side electrical path 22L opposite to the inverter 20 and the second battery 32 side.

[0192] ·like Fig.34 As shown, the positive terminal of the first storage battery 31 and the high potential side electric path 22H can be connected through the first fuse 110A. In addition, the negative terminal of the second storage battery 32 and the low potential side electric path 22L can be connected through the second fuse 110B.

[0193] When the control device 100 determines that there is a power transmission request during the travel of the vehicle CA, the control device 100 may perform the voltage equalization process or capacity equalization process described above while opening and closing the inverter 20 to control the control amount (torque) of the motor 10 to the target value. Figure 1 The circuit structure shown is based on Fig.35 Provide explanation.

[0194] In step S30 , it is determined whether the vehicle CA is traveling.

[0195] If it is determined in step S30 that the vehicle is traveling, the process proceeds to step S31 to determine whether there is a request for power transmission. Here, if the above-mentioned condition (c) is satisfied, it is determined that there is a request for power transmission.

[0196] If it is determined in step S31 that there is no power transmission request, the process proceeds to step S32 to open and close the inverter 20 so as to control the torque of the motor 10 to a target value and cause the vehicle CA to travel. Here, the motor-side switch 60 and the negative electrode bypass switch 50 are opened.

[0197] On the other hand, if it is determined in step S31 that there is a power transmission request, the process proceeds to step S33, and the inverter 20 is opened and closed to control the torque of the motor 10 to the target value so that the vehicle CA travels. At the same time as this opening and closing, the inverter 20 for the above-mentioned capacity equalization process is also opened and closed. Here, the operation mode is set to the series neutral point mode.

[0198] Thus, the vehicle CA can be driven and controlled by the motor 10 while suppressing a large difference in the charging rates of the first and second batteries 31 and 32. Therefore, the charging rate of one of the first and second batteries 31 and 32 can be maintained at a level higher than the allowable lower limit, and the charging rate of the other can be suppressed from reaching the allowable lower limit, thereby extending the driving distance of the vehicle CA.

[0199] Each main switch SMRH, SMRL, each charging switch DCRH, DCRL, inter-battery switch 40, bypass switch, motor-side switch and connection switch is not limited to being composed of a single switch, but may be composed of a series connection of multiple switches or a parallel connection of multiple switches.

[0200] The switch of the inverter 20 is not limited to an IGBT with a freewheeling diode connected in antiparallel, but may be, for example, an N-channel MOSFET including a body diode. In this case, the high potential side terminal of the N-channel MOSFET serves as a drain, and the low potential side terminal serves as a source.

[0201] ·It is not necessary to provide a motor-side switch in the motor-side electrical path.

[0202] The motor is not limited to star connection, but may be delta connection. In addition, the motor and inverter are not limited to three-phase, but may be two-phase or four-phase or more. In addition, the motor is not limited to a permanent magnet type synchronous machine having a permanent magnet as an excitation pole on the rotor, but may be a winding excitation type synchronous machine having an excitation winding as an excitation pole on the rotor. In this case, the rotor may have both an excitation winding and a permanent magnet. In addition, the motor is not limited to a synchronous machine, but may be an induction machine.

[0203] The power storage unit to be charged by the external charger is not limited to a battery, and may be, for example, a large-capacity electric double layer capacitor, or may include both a battery and an electric double layer capacitor.

[0204] The mobile object on which the power conversion device is installed is not limited to a vehicle, and may be, for example, an airplane or a ship. In addition, the installation location of the power conversion device is not limited to a mobile object, and may be a stationary device.

[0205] ·The control unit and the method thereof described in the present disclosure may also be implemented by a special-purpose computer, which is provided by constituting a processor and a memory, and the above-mentioned processor is programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and the method of the control unit described in the present disclosure may be implemented by a special-purpose computer, which is provided by constituting a processor composed of one or more special-purpose hardware logic circuits. Alternatively, the control unit and the method of the control unit described in the present disclosure may be implemented by one or more special-purpose computers, which are constituted by a combination of a processor and a memory programmed to execute one or more functions and a processor constituted by one or more hardware logic circuits. In addition, the computer program may also be stored in a computer-readable non-temporary tangible recording medium as an instruction executed by a computer.

[0206] Although the present disclosure is described based on the embodiments, it should be understood that the present disclosure is not limited to the above-mentioned embodiments and structures. The present disclosure also includes various modifications and modifications within the equivalent range. In addition, various combinations and methods, and other combinations and methods containing only one element, above or below them, also belong to the scope and thought range of the present disclosure.

Claims

1. A power conversion device, comprising: a high potential side electrical path (22H) capable of being electrically connected to the positive terminal of the first power storage unit (31); a low potential side electrical path (22L) capable of being electrically connected to a negative terminal of a second power storage unit (32); an inverter (20) having an upper arm switch (SWH) electrically connected to the high potential side electrical path and a lower arm switch (SWL) electrically connected to the low potential side electrical path; and The electric motor (10) comprises an armature winding (11), wherein the armature winding is electrically connected to a connection point between the upper arm switch and the lower arm switch via a conductive member (23). The power conversion device includes: an inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) electrically connecting the negative terminal of the first storage unit and the positive terminal of the second storage unit; a bypass switch (50, 51) for performing at least one of an electrical connection between the negative terminals of the first power storage unit and the second power storage unit and an electrical connection between the positive terminals of the first power storage unit and the second power storage unit; a motor-side electrical path (25-28) electrically connecting the armature winding or the conductive member to the electrical path between the power storage units; and A control unit (100), The control unit determines whether there is a request for power transmission between the first power storage unit and the second power storage unit, When it is determined that there is a request for power transmission, power transmission between the first power storage unit and the second power storage unit is controlled by opening and closing the inverter while the operation modes of the switch between the power storage units and the bypass switch are set to a first mode or a second mode, the first mode being to turn on the switch between the power storage units and to turn off the bypass switch, and the second mode being to turn off the switch between the power storage units and to turn on the bypass switch.

2. The power conversion device according to claim 1, characterized in that: The control unit permits execution of the second mode when it is determined that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit is equal to or less than a determination threshold value, When it is determined that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit exceeds the determination threshold, execution of the second mode is prohibited.

3. The power conversion device according to claim 2, characterized in that: The bypass switch is an inter-negative electrode bypass switch (50) that electrically connects the negative terminal of the first power storage unit and the negative terminal of the second power storage unit. The motor-side electrical path (25) is a path that electrically connects the armature winding and a position of the inter-storage unit electrical path that is closer to the second storage unit than the inter-storage unit switch. The high potential side electrical path can be electrically connected to the positive terminal of the external charger (200, 210), The low potential side electrical path can be electrically connected to the negative terminal of the external charger, The external charger is a high voltage charger (200) or a low voltage charger (210) having a charging voltage lower than that of the high voltage charger, The control unit determines that there is a request for power transmission when there is a request for charging from the low-voltage charger, When it is determined that the power transmission request is made and execution of the second mode is permitted, the power transmission control is performed while charging is performed by the low voltage charger with the operation mode set to the second mode.

4. The power conversion device according to claim 3, characterized in that: The control unit performs the power transmission control while charging is performed by the low voltage charger in a state where the operation mode is set to the second mode, thereby adjusting the charging power of the first power storage unit and the charging power of the second power storage unit.

5. The power conversion device according to claim 2, characterized in that: The bypass switch is an inter-negative electrode bypass switch (50) that electrically connects the negative terminal of the first power storage unit and the negative terminal of the second power storage unit. The motor-side electrical path (25) is a path that electrically connects the armature winding and a position of the inter-storage unit electrical path that is closer to the second storage unit than the inter-storage unit switch. The high potential side electrical path can be electrically connected to the positive terminal of the external charger (200, 210), The low potential side electrical path can be electrically connected to the negative terminal of the external charger, The external charger is a high voltage charger (200) or a low voltage charger (210) having a charging voltage lower than that of the high voltage charger, The control unit determines that there is a request for power transmission when there is a request for charging from the low-voltage charger, When it is determined that the power transmission request is made and execution of the second mode is prohibited, the operation mode is set to the first mode.

6. The power conversion device according to claim 5, characterized in that: The control unit, in a state where the operation mode is set to the first mode, switches the upper arm switch of at least one phase on the condition that the upper arm switch and the lower arm switch of the same phase are not turned on at the same time, thereby transmitting power from the second power storage unit to the first power storage unit in such a manner that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit is less than the determination threshold value, When it is determined that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit is equal to or less than the determination threshold, the operation mode is switched to the second mode, and the power transmission control is performed while charging is performed by the low voltage charger.

7. The power conversion device according to claim 2, characterized in that: The bypass switch is a positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit. The motor-side electrical path (25) is a path that electrically connects the armature winding and a position of the inter-storage unit electrical path that is closer to the first storage unit than the inter-storage unit switch. The high potential side electrical path can be electrically connected to the positive terminal of the external charger (200, 210), The low potential side electrical path can be electrically connected to the negative terminal of the external charger, The external charger is a high voltage charger (200) or a low voltage charger (210) having a charging voltage lower than that of the high voltage charger, The control unit determines that there is a request for power transmission when there is a request for charging from the low-voltage charger, When it is determined that the power transmission request is made and execution of the second mode is permitted, the power transmission control is performed while charging is performed by the low voltage charger with the operation mode set to the second mode.

8. The power conversion device according to claim 7, characterized in that: The control unit performs the power transmission control while charging is performed by the low voltage charger in a state where the operation mode is set to the second mode, thereby adjusting the charging power of the first power storage unit and the charging power of the second power storage unit.

9. The power conversion device according to claim 2, characterized in that: The bypass switch is a positive electrode bypass switch (51) that electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit. The motor-side electrical path (25) is a path that electrically connects the armature winding and a position of the inter-storage unit electrical path that is closer to the first storage unit than the inter-storage unit switch. The high potential side electrical path can be electrically connected to the positive terminal of the external charger (200, 210), The low potential side electrical path can be electrically connected to the negative terminal of the external charger, The external charger is a high voltage charger (200) or a low voltage charger (210) having a charging voltage lower than that of the high voltage charger, The control unit determines that there is a request for power transmission when there is a request for charging from the low-voltage charger, When it is determined that the power transmission request is made and execution of the second mode is prohibited, the operation mode is set to the first mode.

10. The power conversion device according to claim 9, characterized in that: The control unit, in a state where the operation mode is set to the first mode, switches the lower arm switch of at least one phase on the condition that the upper arm switch and the lower arm switch of the same phase are not turned on at the same time, thereby transmitting power from the first power storage unit to the second power storage unit in such a manner that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit is less than the determination threshold value, When it is determined that the difference between the voltage of the first power storage unit and the voltage of the second power storage unit is equal to or less than the determination threshold, the operation mode is switched to the second mode, and the power transmission control is performed while charging is performed by the low voltage charger.

11. The power conversion device according to any one of claims 5, 6, 9 and 10, characterized in that: comprising charging switches (DCRH, DCRL), the charging switches being provided in the high potential side electrical path and the low potential side electrical path, the charging switches being electrically connected to the external charger and the first power storage unit and the second power storage unit by being turned on, and being electrically disconnected from the external charger and the first power storage unit and the second power storage unit by being turned off, The control unit sets the operation mode to the first mode when the charging switch is in an OFF state.

12. The power conversion device according to claim 2, characterized in that: The high potential side electrical path can be electrically connected to the positive terminal of the external charger (200, 210), The low potential side electrical path can be electrically connected to the negative terminal of the external charger, The external charger is a high voltage charger (200) or a low voltage charger (210) having a charging voltage lower than that of the high voltage charger, the control unit determines that the power transmission request is made when there is a charging request from the high-voltage charger, When it is determined that the power transmission request is made, the control unit performs the power transmission control while charging at least one of the first power storage unit and the second power storage unit by the high-voltage charger in a state where the operation mode is set to the first mode.

13. The power conversion device according to claim 12, characterized in that: The control unit performs the power transmission control while charging at least one of the first power storage unit and the second power storage unit by the high-voltage charger when the operation mode is set to the first mode, thereby adjusting the charging power of the first power storage unit and the charging power of the second power storage unit respectively.

14. The power conversion device according to claim 1, characterized in that: comprising a motor-side switch (60) disposed in the motor-side electrical path, the control unit calculates the total number of times the switch between power storage units, the bypass switch, and the motor side switch are opened and closed when the current operation mode is shifted to the next operation mode via the power transmission control selected as the first mode, calculating the total number of times the inter-storage unit switch, the bypass switch, and the motor-side switch are opened and closed when the current operation mode is shifted to the next operation mode via the power transmission control selected as the second mode, When the execution of the second mode is permitted, the mode with the smaller total number of switching times is selected between the first mode and the second mode in the power transmission control.

15. The power conversion device according to claim 1, characterized in that: comprising a motor-side switch (60) disposed in the motor-side electrical path, The control unit calculates the total number of times the switch between power storage units, the bypass switch, and the motor side switch are opened and closed when the current operation mode is shifted to the power transmission control selected as the first mode, calculating the total number of times the switch between the power storage units, the bypass switch, and the motor-side switch are opened and closed when the current operation mode is shifted to the power transmission control selected as the second mode, When the execution of the second mode is permitted, the mode with the smaller total number of switching times is selected between the first mode and the second mode in the power transmission control.

16. The power conversion device according to claim 1, characterized in that: any one of the voltage of the first power storage unit and the second power storage unit, the charging rate of the first power storage unit and the second power storage unit, and the correlation value of the voltage or the charging rate of the first power storage unit and the second power storage unit is used as a capacity parameter, The control unit determines that the power transmission request is made when it is determined that the difference between the capacity parameter of the first power storage unit and the capacity parameter of the second power storage unit exceeds a threshold value, When it is determined that the power transmission request is made, the power transmission control is performed so that the difference between the capacity parameter of the first power storage unit and the capacity parameter of the second power storage unit becomes small while the operation mode is set to the first mode or the second mode.

17. The power conversion device according to claim 1, characterized in that: The control unit determines that the power transmission request is made when it is determined that the temperature of the first power storage unit and the second power storage unit or any one of the values ​​related to the temperature, that is, the temperature parameter, is lower than a temperature threshold value, When it is determined that there is the power transmission request, the power transmission control is performed in a state where the operation mode is set to the first mode or the second mode so that the charging and discharging current flows between the first power storage unit and the second power storage unit via the armature winding and the inverter.

18. The power conversion device according to claim 1, characterized in that: The power conversion device is installed on the mobile body (CA), The electric motor is used as a power source for moving the moving body. The control unit performs the power transmission control while opening and closing the inverter for moving the moving object, when it is determined that the power transmission request is made during the movement of the moving object.

19. A program, applicable to a power conversion device, the power conversion device comprising: a high potential side electrical path (22H) capable of being electrically connected to the positive terminal of the first power storage unit (31); a low potential side electrical path (22L) capable of being electrically connected to a negative terminal of a second power storage unit (32); an inverter (20) having an upper arm switch (SWH) electrically connected to the high potential side electrical path and a lower arm switch (SWL) electrically connected to the low potential side electrical path; and An electric motor (10) having an armature winding (11), wherein the armature winding is electrically connected to a connection point of the upper arm switch and the lower arm switch via a conductive member (23); as well as Computer (101), The power conversion device comprises: an inter-storage unit switch (40) provided in an inter-storage unit electrical path (24) electrically connecting the negative terminal of the first storage unit and the positive terminal of the second storage unit; a bypass switch (50, 51) for performing at least one of an electrical connection between the negative terminals of the first power storage unit and the second power storage unit and an electrical connection between the positive terminals of the first power storage unit and the second power storage unit; and a motor-side electrical path (25-28) electrically connecting the armature winding or the conductive member to the electrical path between the power storage units, The program causes the computer to execute the following processing: a process of determining whether there is a request for power transfer between the first power storage unit and the second power storage unit; When it is determined that there is a request for power transmission, power transmission between the first power storage unit and the second power storage unit is controlled by opening and closing the inverter while the operation modes of the switch between the power storage units and the bypass switch are set to a first mode or a second mode, the first mode being to turn on the switch between the power storage units and to turn off the bypass switch, and the second mode being to turn off the switch between the power storage units and to turn on the bypass switch.

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