Power conversion device and program

Abstract

This power conversion device is provided with: an inter-power-storage-unit switch (40) provided in an inter-power-storage-unit electrical path (24) that electrically connects the negative electrode terminal of a first power storage unit (31) and the positive electrode terminal of a second power storage unit (32); bypass switches (50, 51) for electrically connecting the negative electrode terminals of the first and second power storage units and / or electrically connecting the positive electrode terminals of the first and second power storage units; motor-side electrical paths (25-28) that electrically connect the armature winding (11) or the conductive member (23) and the inter-power-storage-unit electrical paths; and a control unit (100). The control unit starts charging of at least one of the first and second power storage units by the external charger (210) in a state where the inter-power storage unit switch is turned off and the bypass switch is turned on, and after the start of charging by the external charger, performs an opening / closing process of the inverter (20) for causing the voltage difference between the first and second power storage units to be equal to or less than a determination threshold value.

Description

Citation of related applications

[0001] This application is based on Japanese Patent Application No. 2022-144019 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] Conventionally, there is known a power supply device capable of switching the connection state of a first battery and a second battery to a series connection state or a parallel connection state, as described in Patent Document 1. The power supply device includes a relay for switching the connection state of the first battery and the second battery to an external charger to a series connection state or a parallel connection state.

[0004] When the voltage difference between the first battery and the second battery is equal to or greater than a threshold value, the power supply device operates the relay so that only the battery with the lower voltage between the first battery and the second battery can be charged by an external charger, thereby equalizing the voltages of the first battery and the second battery.

[0005] On the other hand, when the voltage difference between the first battery and the second battery is less than a threshold value, the power supply device operates the relay in such a manner that the connection state of the first battery and the second battery is switched to a parallel connection state, and both the first battery and the second battery can be charged by an external charger. Thus, the switching to the parallel connection state when the voltage difference between the first battery and the second battery is large is prevented, and an inrush current is prevented from flowing into each battery accompanying the switching. Prior art literature Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-126027 Summary of the invention

[0007] A new power conversion device is desired that can switch the connection state of a first power storage unit such as a first battery and a second power storage unit such as a second battery to an external charger.

[0008] A main object of the present disclosure is to provide a power conversion device and a program capable of switching the connection states of a first power storage unit and a second power storage unit with respect to an external charger.

[0009] 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 and a positive terminal of an external charger; a low potential side electrical path electrically connectable to the negative terminal of the second power storage unit and the negative terminal of the external charger; 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 a motor having an armature winding electrically connected to a connection point of 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 starts charging at least one of the first power storage unit and the second power storage unit by the external charger in a state where the switch between power storage units is turned off and the bypass switch is turned on. After charging by the external charger starts, a process of switching the inverter, that is, a voltage adjustment process, is performed so that the voltage difference between the first power storage unit and the second power storage unit becomes equal to or less than a determination threshold.

[0010] In the present disclosure, by turning on the switch between the storage units and turning off the bypass switch, the first storage unit and the second storage unit are connected in series with respect to the external charger. On the other hand, by turning off the switch between the storage units and turning on the bypass switch, either the first storage unit or the second storage unit is connected in parallel with respect to the external charger. In this way, according to the present disclosure, the connection state of the first storage unit and the second storage unit with respect to the external charger can be switched.

[0011] The control unit of the present disclosure starts charging at least one of the first power storage unit and the second power storage unit through an external charger while the switch between the power storage units is disconnected and the bypass switch is connected. After the charging of the external charger starts, the control unit performs an opening and closing process of the inverter, i.e., a voltage regulation process, for making the voltage difference between the first power storage unit and the second power storage unit below a judgment threshold. In the voltage regulation process, electric power is transferred between the first power storage unit and the second power storage unit via the inverter and the armature winding so that the voltage difference is below the judgment threshold. In this way, it is possible to suppress a large current caused by a large voltage difference between the first power storage unit and the second power storage unit from flowing from one of the first power storage unit and the second power storage unit to the other via the inverter and the armature winding.

[0012] Furthermore, the configuration of the motor and the inverter is retained in order to make the voltage difference between the first power storage unit and the second power storage unit equal to or less than the determination threshold value. Therefore, a power conversion device having a simplified configuration can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] 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 2 is a diagram showing the operation of the switch in the high voltage charging mode. Figure 3 1 is a diagram showing the operation of the switches in the low voltage charging mode. Figure 4 1 is a diagram showing the operation of the switch in Mode 2 of the low voltage charging mode. Figure 5 1 is a diagram showing the operation manner of the switch in Mode 3 of the low voltage charging mode. Figure 6 : is a flowchart showing the procedure of the battery charging process. Figure 7 It is a timing chart showing an example of charging processing. Figure 8 It is a timing chart showing an example of charging processing. Fig. 9 It is a timing chart showing an example of charging processing. Fig.10 It is a diagram showing the overall configuration of the system according to the second embodiment. Fig.11 1 is a diagram showing the operation of the switches in the low voltage charging mode. Fig.12 1 is a diagram showing the operation of the switch in Mode 2 of the low voltage charging mode. Fig.13 1 is a diagram showing the operation manner of the switch in Mode 3 of the low voltage charging mode. Fig.14 : is a flowchart showing the procedure of the battery charging process. Fig.15 It is an overall structural diagram of a system according to another embodiment. Fig.16 It is an overall structural diagram of a system according to another embodiment. Fig.17 It is an overall structural diagram of a system according to another embodiment. Fig.18 It is an overall structural diagram of a system according to another embodiment. Fig.19 It is an overall structural diagram of a system according to another embodiment. Fig. 20 It is an overall structural diagram of a system according to another embodiment. Fig.21 It is an overall structural diagram of a system according to another embodiment. Fig. 22 It is an overall structural diagram of a system according to another embodiment. Fig.23 It is an overall structural diagram of a system according to another embodiment. Fig.24 It is an overall structural diagram of a system according to another embodiment. Fig.25 It is an overall structural diagram of a system according to another embodiment. Fig.26 It is an overall structural diagram of a system according to another embodiment. Fig. 27 It is an overall structural diagram of a system according to another embodiment. Fig.28 It is an overall structural diagram of a system according to another 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 a diagram showing the operation mode of each switch. Fig.32 It is an overall structural diagram of a system according to another embodiment. DETAILED DESCRIPTION

[0014] 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.

[0015] <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.

[0016] The system installed in the vehicle CA includes a power conversion device. Figure 1As 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 is capable of transmitting power to the drive wheels of the vehicle CA. Therefore, the motor 10 is a source of torque that causes the vehicle CA to travel.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] 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.

[0021] 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 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, and the negative terminal of the second battery 32 is connected to the 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. 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.

[0022] The batteries 31 and 32 of the present embodiment are batteries having the same rated voltage and full charge capacity. The batteries 31 and 32 can be charged by an external charger to be described later and provided outside the vehicle CA. The external charger is, for example, a stationary charger. A positive electrode side connection portion that can be connected to the positive terminal of the external charger is provided on the first end side of the high potential side electrical path 22H. A negative electrode side connection portion that can be connected to the negative terminal of the external charger is provided on the first end side of the low potential side electrical path 22L.

[0023] The power conversion device includes a main switch for electrically connecting or disconnecting the first and second storage batteries 31, 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 inverter 20. 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, the high potential side main switch SMRH and the high potential side charging switch DCRH are provided in sequence from the first storage battery 31 side. In the low potential side electrical path 22L, the low potential side main switch SMRL and the low potential side charging switch DCRL are provided in sequence from the second storage battery 32 side. Furthermore, 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 switch elements.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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 on 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 on an electrical path connecting the negative terminal of the second battery 32 and the low potential side electrical path 22L. 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.

[0029] 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 6 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.

[0030] 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.

[0031] 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 2 to Figure 5). 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.

[0032] On the other hand, when charging by the external charger is not performed or the 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.

[0033] Control device 100 selects and executes either a high-voltage charging mode in which high-voltage charger 200 charges the battery or a low-voltage charging mode in which low-voltage charger 210 charges the battery.

[0034] First, use Figure 2 The high-voltage charging mode will be described.

[0035] When the control device 100 determines that the external charger connected to each connection portion is the high-voltage charger 200, the control device 100 executes the high-voltage charging mode. In the high-voltage charging mode, the control device 100 turns on the inter-battery switch 40 and each main switch SMRH, SMRL, and turns off the inter-negative electrode bypass switch 50, the motor side switch 60, and the upper and lower arm switches SWH, SWL of the inverter 20, so that the first battery 31 and the second battery 32 are connected in series with the high-voltage charger 200. As a result, Figure 2 As shown, the current flows in the 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. At this time, since the upper arm switch SWH and the motor side switch 60 of the inverter 20 are turned off, the charging current of the high-voltage charger 200 can be prevented from flowing through the inverter 20 and the armature winding 11.

[0036] Next, use Figure 3 to Figure 5 The low voltage charging mode is described.

[0037] When the control device 100 determines that the external charger connected to each connection portion is the low voltage charger 210, the control device 100 executes the low voltage charging mode. Figure 3 The model shown is Figure 4 Mode 2 shown and Figure 5 Mode three is shown.

[0038] First, use Figure 3 Mode 1 is described below. In mode 1, the control device 100 turns off the inter-battery switch 40, the motor-side switch 60, and the upper and lower arm switches SWH and SWL of the inverter 20, and turns on the inter-negative electrode bypass switch 50 and the main switches SMRH and SMRL. Figure 3 As shown, only the first storage battery 31 of the first and second storage batteries 31 and 32 is charged by the low voltage charger 210. In mode 1, the second storage battery 32 is not charged.

[0039] Next, use Figure 4 Mode 2 is described below. In mode 2, the control device 100 turns off the inter-battery switch 40, the high-potential side main switch SMRH, and the lower arm switch SWL of the inverter 20, and turns on the negative electrode bypass switch 50, the motor side switch 60, the low-potential side main switch SMRL, and the upper arm switch SWH of at least one phase of the inverter 20. Figure 4 As shown, only the second battery 32 of the first and second batteries 31 and 32 is charged by the low voltage charger 210. At this time, the charging current from the low voltage charger 210 flows through the upper arm switch SWH, the conductive member 23, the armature winding 11 and the motor side electrical path 25. In mode 2, the first battery 31 is not charged.

[0040] Next, use Figure 5 Mode 3 is described. In mode 3, the control device 100 turns off the inter-battery switch 40 and turns on the inter-negative bypass switch 50, the motor side switch 60, and the main switches SMRH and SMRL. In mode 3, the charging power of the first storage battery 31 and the second storage 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 alternately turning on the upper and lower arm switches SWH and SWL of at least one phase of the inverter 20 while outputting the charging current from the low voltage charger 210, or repeatedly turning on and off the upper arm switch SWH of at least one phase and turning off the lower arm switch SWL. Here, by adjusting the ratio of the on period Ton of the upper arm switch SWH to one opening and closing cycle Tsw, that is, the duty cycle (Ton / Tsw), the charging power of the first storage battery 31 and the second storage battery 32 can be adjusted separately. According to mode 3, both the first and second storage batteries 31 and 32 can be charged.

[0041] Here, when charging the battery in the low voltage charging mode with the motor side switch 60 turned on, if 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, a large current will flow 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. In this case, the reliability of the power conversion device or each battery 31, 32 may be reduced.

[0042] Therefore, in order to suppress the current from flowing from the second battery 32 to 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, the control device 100 performs the low voltage charging mode. Figure 6 The charging process shown in FIG. 1 is repeatedly executed by the control device 100, for example, in a predetermined control cycle. Figure 6 The processing shown is executed, for example, while the vehicle CA is stopped (for example, while the vehicle is parked in a specific example).

[0043] In step S10 , it is determined that the current time is the charging start time during the charging control period, and charging in the low-voltage charging mode is started.

[0044] In step S11, it is determined whether the absolute value of the difference between the voltage between the terminals of the first battery 31 detected by the first voltage sensor 71 (hereinafter, the first detection voltage VA) and the voltage between the terminals of the second battery 32 detected by the second voltage sensor 72 (hereinafter, the second detection voltage VB) is less than or equal to a determination threshold value ΔVjde. The process of step S11 is a process for determining whether a current flowing from the second battery 32 to the first battery 31 via the motor 10 and the inverter 20 is increasing.

[0045] In addition, the determination threshold value ΔVjde can be set to a voltage difference between the first battery 31 and the second battery 32 whose maximum value of the inrush current and the steady-state value are below the allowable value determined by 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" when the motor-side switch 60 is turned on. Here, the allowable value is, for example, the maximum current that the structural components on the current path can safely withstand.

[0046] The determination threshold ΔVjde is a value smaller than the rated voltage of each battery 31, 32. The determination threshold ΔVjde is set to, for example, 1 / 10 or less, 1 / 20 or less, 1 / 50 or less, or 1 / 100 or less of the lower value of the rated voltage of each battery 31, 32.

[0047] If a positive determination is made in step S11, the process proceeds to step S12, and the operation is performed in such a way as to maintain "|VA ≥ VB|" and "|VA-VB| ≤ ΔVjde". Figure 5 Mode 3 shown. The process of step S12 corresponds to the voltage adjustment process.

[0048] Next, in step S13, it is determined whether the current time is a specific time. The specific time is, for example, the following time (A) to (E).

[0049] Timing (A): The power Wout for charging the first storage battery 31 among the output charging power of the low voltage charger 210 becomes larger than the allowable charging power Win of the first storage battery 31 .

[0050] The allowable charging power refers to the maximum value of the charging power at which the reliability of the battery does not decrease. When the charging of the first battery 31 progresses and the SOC becomes higher, the allowable charging power of the first battery 31 becomes smaller. Therefore, when charging progresses, the time comes when the charging power Wout of the first battery 31 among the output charging power of the low-voltage charger 210 becomes larger than the allowable charging power Win of the first battery 31. By transferring to step S17 described later at this time, the surplus output power of the low-voltage charger 210 with respect to the first battery 31 can be effectively and flexibly used for charging the second battery 32.

[0051] Timing (B): The charging mode of the low voltage charger 210 is switched from the constant current mode CC in which the output current from the low voltage charger 210 is set to a constant value to the constant voltage mode CV in which the output voltage of the low voltage charger 210 is set to a constant value.

[0052] The charging power of the battery is greater in the constant current mode than in the constant voltage mode. Therefore, when switching to the constant voltage mode, there may be surplus output power of the low voltage charger 210 relative to the first battery 31. In this case, the surplus power can be effectively used to charge the second battery 32. In addition, it is sufficient to switch to the constant voltage mode when it is determined that the first detection voltage VA is greater than the specified voltage.

[0053] Timing (C): The charging mode of the low voltage charger 210 is switched from the constant current mode CC to the constant power mode CP in which the output power of the low voltage charger 210 is set to a constant value.

[0054] The charging power of the battery is greater in the constant current mode than in the constant power mode. Therefore, when switching to the constant power mode, there may be surplus output power of the low voltage charger 210 relative to the first battery 31. In this case, the surplus power can be effectively and flexibly used to charge the second battery 32.

[0055] Time (D): A predetermined period of time before the charging end time during the charging control period.

[0056] The time of (D) is used, for example, when the charging control period is set to a predetermined fixed period (for example, 20 minutes). For example, if the prescribed period is set to 5 minutes, the specific time is the time when 15 minutes have passed from the start time of charging. According to the time of (D), for example, even if the charging process is terminated without fully charging the first and second batteries 31 and 32, the remaining capacity, charging rate or terminal voltage of the first and second batteries 31 and 32 can be equalized. Here, the remaining capacity refers to the battery capacity after taking into account the capacity of the new battery, the degree of deterioration, and the charging rate, for example, expressed by the following formula. In the following formula, SOH represents the degree of deterioration of the battery.

[0057] Remaining capacity (Ah) = Full charge capacity (Ah) × SOC (%) =(capacity at the time of new product〔Ah〕×SOH〔%〕)×SOC〔%〕 At the time of (E): the charge rate (SOC) of the first battery 31 is a value obtained by subtracting a predetermined charge rate from the target charge rates (e.g., 80%) of the first and second batteries 31 and 32 at the time of charging completion. Alternatively, for example, the charge rate of the first battery 31 may be calculated based on the detection values ​​of the first voltage sensor 71 and the first current sensor 73.

[0058] If it is determined in step S13 that the current time is not the specific time, the process proceeds to step S11. On the other hand, if it is determined that the current time is the specific time, the process proceeds to step S17.

[0059] In step S17, the voltage adjustment process is performed for the period after the specific moment in the charging control period. Specifically, while maintaining "VA ≥ VB" and "|VA-VB| ≤ ΔVjde", mode three is executed in a form in which the difference between the first and second detection voltages VA and VB at the end of charging during the charging control period is smaller than the difference between the first and second detection voltages VA and VB at the specific moment. In addition, mode three is executed in a manner in which the charging current IB of the second storage battery 32 is larger than the charging current IA of the first storage battery 31. According to the process of step S17, for example, the difference between the first and second detection voltages VA and VB gradually decreases. As a result, the remaining capacity, charging rate or terminal voltage of the first and second storage batteries 31 and 32 can be equalized.

[0060] In step S18, it is determined whether the current time is the charging end time. The process of step S17 is continued until an affirmative determination is made in step S18.

[0061] At the start of charging, the voltage between the terminals of the first storage battery 31 and the voltage between the terminals of the second storage battery 32 may differ greatly. In this case, a negative determination is made in step S11, and a pre-charging process is performed in steps S14 to S16 before the voltage adjustment process in step S11 is performed to reduce the difference between the first and second detection voltages VA and VB. Specifically, first, in step S14, it is determined whether the second detection voltage VB is higher than the first detection voltage VA.

[0062] In step S14, if it is determined that the second detection voltage VB is higher than the first detection voltage VA, the process proceeds to step S15. In other words, if it is determined that the first detection voltage VA is lower than the value obtained by subtracting the determination threshold ΔVjde from the second detection voltage VB, the process proceeds to step S15. In step S15, the first mode (refer to FIG. 1 ) in which only the first storage battery 31 of the first and second storage batteries 31 and 32 is charged by the low voltage charger 210 is executed so that the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold ΔVjde. Figure 3 ). Then, the process proceeds to step S13. In addition, in step S15, mode 1 may be further executed to make "VA ≥ VB". Thus, the state where the charging rates of the first and second batteries 31 and 32 are greatly different can be eliminated as soon as possible, and at the same time, the current can be reliably suppressed from flowing from the second battery 32 to the first battery 31 via the armature winding 11 and the inverter 20.

[0063] On the other hand, if it is determined in step S14 that the second detection voltage VB is lower than the first detection voltage VA, the process proceeds to step S16. In step S16, the second mode (see FIG. 2 ) is executed in which only the second storage battery 32 of the first and second storage batteries 31 and 32 is charged by the low voltage charger 210 so that the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold value ΔVjde. Figure 4 ). Then, the process proceeds to step S13. Thus, the state in which the charging rates of the first and second storage batteries 31 and 32 are greatly different can be eliminated as soon as possible. In addition, in step S16, mode 2 can be further executed to make "VA ≥ VB".

[0064] In addition, in step S16, mode 3 may be executed instead of mode 2. Specifically, mode 3 may be executed in such a manner that the charging current of the second storage battery 32 is larger than that of the first storage battery 31 and the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold value ΔVjde. In this way, the difference between the first and second detection voltages VA and VB can be reduced, and the charging period of the first and second storage batteries 31 and 32 can be shortened.

[0065] Next, use Figure 7 to Figure 9 An example of the charging process will be described.

[0066] First of all, Figure 7 The following example is used to illustrate this.

[0067] The control device 100 starts the charging process at time t1. Here, at the start of charging, the control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB exceeds the determination threshold ΔVjde. In addition, the control device 100 determines that the first detection voltage VA is lower than the second detection voltage VB. Therefore, the control device 100 executes mode 1 of step S15. As a result, the first storage battery 31 is charged and the first detection voltage VA starts to rise. On the other hand, the second storage battery 32 is not charged, so the second detection voltage VB is constant.

[0068] The control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB is equal to or less than the determination threshold value ΔVjde at time t2. Therefore, the control device 100 executes the mode 3 of step S12.

[0069] The control device 100 determines that the specific time is reached at time t3. Therefore, the control device 100 executes the mode 3 of step S17 until the charging end time of the charging control period, that is, time t4. Since the charging current IB of the second storage battery 32 is larger than the charging current IA of the first storage battery 31, the rising speed of the second detection voltage VB is higher than the rising speed of the first detection voltage VA. As the time t4 is approached, the difference between the first and second detection voltages VA and VB becomes smaller. The difference between the first and second detection voltages VA and VB at time t4 is smaller than the difference between the first and second detection voltages VA and VB at time t3, for example, smaller than the determination threshold ΔVjde.

[0070] Next, Figure 8 The following example is used to illustrate this.

[0071] The control device 100 starts the charging process at time t1. Here, at the start of charging, the control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB exceeds the determination threshold ΔVjde. In addition, the control device 100 determines that the second detection voltage VB is lower than the first detection voltage VA. Therefore, the control device 100 executes mode 2 of step S16. As a result, the second storage battery 32 is charged, and the second detection voltage VB starts to rise.

[0072] The control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB is equal to or less than the determination threshold value ΔVjde at time t2. Therefore, the control device 100 executes the mode 3 of step S12.

[0073] The control device 100 determines that the specific time has come at time t3. Therefore, the control device 100 executes the mode 3 of step S17 until the charging control period ends, that is, at time t4.

[0074] Next, Fig. 9 The following example is used to illustrate this. Fig. 9 This is an example of executing mode 3 in place of mode 2 in step S16 so that the charging current of the second battery 32 is larger than that of the first battery 31 and the absolute value of the difference between the first and second detection voltages VA and VB is equal to or less than the determination threshold ΔVjde.

[0075] The control device 100 starts the charging process at time t1. Here, at the start of charging, the control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB exceeds the determination threshold ΔVjde. In addition, the control device 100 determines that the second detection voltage VB is lower than the first detection voltage VA. Therefore, the control device 100 executes mode 3 of step S16. As a result, the first and second batteries 31 and 32 are charged, and the first and second detection voltages VA and VB begin to rise. At this time, since the charging current of the second battery 32 is larger than that of the first battery 31, the rising speed of the second detection voltage VB is higher than that of the first detection voltage VA.

[0076] The control device 100 determines that the absolute value of the difference between the first and second detection voltages VA and VB is equal to or less than the determination threshold value ΔVjde at time t2. Therefore, the control device 100 executes the mode 3 of step S12.

[0077] The control device 100 determines that the specific time has come at time t3. Therefore, the control device 100 executes the mode 3 of step S17 until the charging control period ends, that is, at time t4.

[0078] According to the present embodiment described above, it is possible to suppress the occurrence of a phenomenon in which current flows from the second battery 32 to the first battery 31 via the motor 10 and the inverter 20 , or to reduce the amount of current that flows even if such a phenomenon occurs.

[0079] In addition, in order to make the absolute value of the difference between the first and second detection voltages VA and VB less than the determination threshold value ΔVjde, the structure of the motor 10 and the inverter 20 is retained. As a result, it is not necessary to include additional electrical equipment (such as a DCDC converter) in the power conversion device in order to suppress the occurrence of the phenomenon that the current flows from the second battery 32 to the first battery 31 via the motor 10 and the inverter 20, or to reduce the amount of current flowing in even if the phenomenon occurs. Therefore, it is possible to provide a power conversion device that realizes a simplified structure.

[0080] <Modification of the first embodiment> If in Figure 6 In steps S12, S15 to S17, the relationship of "|VA-VB|≤ΔVjde" is maintained, and it can also be "VA<VB".

[0081] <Second embodiment> Hereinafter, referring to the accompanying drawings, the second embodiment will be described with a focus on the differences from the first embodiment. Fig.10 As shown, the power conversion device includes a positive electrode bypass switch 51, excluding the previous Figure 1The 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.

[0082] Next, the high-voltage charging mode of the present embodiment will be described.

[0083] In the high-voltage charging mode, the control device 100 turns on the inter-battery switch 40 and the main switches SMRH and SMRL, and turns off the inter-positive bypass switch 51, the motor side switch 61 and the upper and lower arm switches SWH and SWL of the inverter 20, so that the first battery 31 and the second battery 32 are connected in series with respect to the high-voltage charger 200.

[0084] Next, use Figure 11 to Figure 13 The low voltage charging mode is described.

[0085] First, use Fig.11 Mode 1 is described below. In mode 1, the control device 100 turns off the inter-battery switch 40, the motor side switch 61, and the upper and lower arm switches SWH and SWL of the inverter 20, and turns on the positive electrode bypass switch 51 and the main switches SMRH and SMRL. Fig.11 As shown, only the second storage battery 32 of the first and second storage batteries 31 and 32 is charged by the low voltage charger 210. In mode 1, the first storage battery 31 is not charged.

[0086] Next, use Fig.12 Mode 2 is described below. In mode 2, the control device 100 turns off the inter-battery switch 40 and the upper arm switch SWH of the inverter 20, and turns on the positive electrode bypass switch 51, the motor side switch 61, the high potential side main switch SMRH, and the lower arm switch SWL of at least one phase of the inverter 20. Fig.12 As shown, only the first battery 31 of the first and second batteries 31 and 32 is charged by the low voltage charger 210. At this time, the charging current from the low voltage charger 210 flows through the motor side electrical path 25, the armature winding 11, the conductive member 23 and the lower arm switch SWL. In mode 2, the second battery 32 is not charged. In addition, in mode 2, the low potential side main switch SMRL can be either turned on or off.

[0087] Next, use Fig.13Mode 3 is described. In mode 3, the control device 100 turns off the inter-battery switch 40 and turns on the positive electrode bypass switch 51, the motor side switch 61, and the main switches SMRH and SMRL. In mode 3, 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 alternately turning on the upper and lower arm switches SWH and SWL of at least one phase of the inverter 20 while outputting the charging current from the low voltage charger 210, or repeatedly turning on and off the lower arm switch SWL of at least one phase and turning off the upper arm switch SWH. 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 cycle (Ton / Tsw), the charging power of the first battery 31 and the second battery 32 can be adjusted separately. According to mode 3, both the first and second batteries 31 and 32 can be charged.

[0088] Here, when the battery is charged in a low-voltage charging mode with the motor side switch 61 turned on, if the terminal voltage of the first battery 31 is too high relative to the terminal voltage of the second battery 32, a closed circuit including the first battery 31, the positive electrode bypass switch 51, the lower arm diode DL connected in reverse parallel to the lower arm switch SWL, the armature winding 11 and the motor side electrical path 25 will be formed, and current will flow from the first battery 31 to the second battery 32.

[0089] Therefore, the control device 100 performs the low voltage charging mode. Fig.14 The charging process shown in FIG. 1 is repeatedly executed by the control device 100, for example, in a predetermined control cycle. Fig.14 The processing shown is executed, for example, while the vehicle CA is stopped (for example, while the vehicle is parked in a specific example).

[0090] In step S20 , it is determined that the current time is the charging start time during the charging control period, and charging in the low-voltage charging mode is started.

[0091] In step S21 , it is determined whether the absolute value of the difference between the second detection voltage VB and the first detection voltage VA is less than or equal to a determination threshold value ΔVjde.

[0092] If a positive determination is made in step S21, the process proceeds to step S22, and the operation is performed in such a way as to maintain "VB ≥ VA" and "|VB-VA| ≤ ΔVjde". Fig.13 Mode three is shown.

[0093] Next, in step S23, it is determined whether the current time is a specific time. The specific time is, for example, the time (A) to (E) described above.

[0094] The timing of (A) mentioned above can be any timing when the charging power Wout for the second battery 32 among the output charging power of the low voltage charger 210 becomes larger than the allowable charging power Win of the second battery 32. The timing of (E) mentioned above can be any timing when the charging rate of the second battery 32 becomes the value obtained by subtracting the prescribed charging rate from the target charging rate of the first and second batteries 31 and 32 at the end of charging. For example, the charging rate of the second battery 32 can be calculated based on the detection values ​​of the second voltage sensor 72 and the second current sensor 74.

[0095] If it is determined in step S23 that the current time is not the specific time, the process proceeds to step S21. On the other hand, if it is determined that the current time is the specific time, the process proceeds to step S27.

[0096] In step S27, the voltage adjustment process is performed for the period after the specific time in the charge control period. Specifically, while maintaining "VB ≥ VA" and "|VB-VA| ≤ ΔVjde", the mode 3 is executed so that the difference between the first and second detection voltages VA and VB at the end of the charge control period is smaller than the difference between the first and second detection voltages VA and VB at the specific time. In addition, the mode 3 is executed so that the charging current IA of the first storage battery 31 is larger than the charging current IB of the second storage battery 32.

[0097] In step S28, it is determined whether the current time is the charging end time. The process of step S27 is continued until an affirmative determination is made in step S28.

[0098] At the start of charging, the voltage between the terminals of the second storage battery 32 and the voltage between the terminals of the first storage battery 31 may be greatly different. In this case, a negative determination is made in step S21, and a pre-charging process is performed in steps S24 to S26 before the voltage adjustment process in step S21 is performed to reduce the difference between the first and second detection voltages VA and VB. Specifically, first, in step S24, it is determined whether the first detection voltage VA is higher than the second detection voltage VB.

[0099] In step S24, when it is determined that the first detection voltage VA is higher than the second detection voltage VB, the process proceeds to step S25. In other words, when it is determined that the second detection voltage VB is lower than the value obtained by subtracting the determination threshold ΔVjde from the first detection voltage VA, the process proceeds to step S25. In step S25, the first mode (refer to FIG. 1 ) in which only the second storage battery 32 of the first and second storage batteries 31 and 32 is charged by the low voltage charger 210 is executed so that the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold ΔVjde. Fig.11). Then, the process proceeds to step S23. In addition, in step S25, mode 1 may be further executed to make "VB ≥ VA".

[0100] On the other hand, if it is determined in step S24 that the first detection voltage VA is lower than the second detection voltage VB, the process proceeds to step S26. In step S26, the low voltage charger 210 is used to charge only the first storage battery 31 of the first and second storage batteries 31 and 32 so that the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold value ΔVjde. Fig.12 ). Then, the process proceeds to step S23. In addition, in step S26, mode 2 may be further executed to make "VB ≥ VA".

[0101] In step S26, mode 3 may be executed instead of mode 2. Specifically, mode 3 may be executed so that the charging current of the first battery 31 is larger than that of the second battery 31 and the absolute value of the difference between the first and second detection voltages VA and VB is less than the determination threshold ΔVjde.

[0102] According to the present embodiment described above, the same effects as those of the first embodiment can be achieved.

[0103] <Other embodiments> In addition, each of the above-mentioned embodiments may be implemented with the following modifications.

[0104] If in the second embodiment Fig.14 In steps S22, S25 to S27, the relationship of "|VB-VA|≤ΔVjde" is maintained, and it can also be "VB<VA".

[0105] The structure of the power conversion device may be the structure described below.

[0106] like Fig.15 As shown in the previous Figure 1 In the illustrated structure, the motor-side switch 60 may not be provided on the motor-side electric path 25 .

[0107] like Fig.16 As shown in the previous Fig.10 In the illustrated structure, the motor-side switch 61 may not be provided on the motor-side electric path 25 .

[0108] like Fig.17 As shown in the previous Figure 1 In the structure shown in the figure, a positive electrode bypass switch 51 may be further included. Figure 6 In the process shown, for example, the positive electrode bypass switch 51 may be opened.

[0109] like Fig.18 As shown in the previous Fig.17 In the illustrated structure, the motor-side switch 60 may not be provided on the motor-side electric path 25 .

[0110] like Fig.19 As shown in the previous Fig.10 In the structure shown in the figure, a negative electrode bypass switch 50 may be further included. Fig.14 In the process shown, for example, the negative electrode bypass switch 50 may be opened.

[0111] like Fig. 20 As shown in the previous Fig.19 In the illustrated structure, the motor-side switch 61 may not be provided on the motor-side electric path 25 .

[0112] like Fig.21 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 may be included.

[0113] Specifically, 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 on 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 on 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.

[0114] In addition, Fig.21 In the structure shown, in the high voltage charging mode and the previous Figure 6 In the process shown in FIG. 1 , for example, the positive electrode bypass switch 51 and the second motor side switch 61 may be turned off. Fig.21 In the structure shown, in the high voltage charging mode and the previous Fig.14 In the process shown, for example, the negative electrode bypass switch 50 and the first motor side switch 60 may be opened.

[0115] like Fig. 22 As shown in the previous Fig.21In the illustrated structure, the first motor-side switch 60 may not be provided on the first electric path 27 .

[0116] like Fig.23 As shown in the previous Fig.21 In the illustrated structure, the second motor-side switch 61 may not be provided on the second electric path 28 .

[0117] like Fig.24 As shown in the previous Fig. 22 In the illustrated structure, the positive electrode bypass switch 51 may not be included.

[0118] like Fig.25 As shown in the previous Fig.21 In the illustrated structure, the positive electrode bypass switch 51 may not be included.

[0119] like Fig.26 As shown in the previous Fig.23 In the illustrated structure, the negative electrode bypass switch 50 may not be included.

[0120] like Fig. 27 As shown in the previous Fig.21 In the illustrated structure, the negative electrode bypass switch 50 may not be included.

[0121] ·like Fig.28 As shown, a third current sensor 75 may be provided at a portion of the high potential side electrical path 22H that is closer to the high potential side charging switch DCRH side than the inverter 20. In addition, a fourth current sensor 76 may be provided at any position of the motor side electrical path 25. For example, a fourth current sensor 76 may be provided at a position that is closer to the neutral point side 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 to 76 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 that detects the current flowing through each conductive member 23 may be provided, and the detection value of the fourth current sensor 76 may be replaced by the total value of the current detection value flowing through each conductive member 23.

[0122] 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.29 As shown, it may be the middle part of the armature winding 11 .

[0123] In addition, the connection of the motor side electric path 25 is as follows, for example Fig.30 As shown, it can also be a conductive member 23. At this time, Fig.31 As shown in the previous Figure 6The opening and closing of the inverter 20 in steps S12 and S17 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.

[0124] ·like Fig.32 As shown, in the high potential side electrical path 22H, a high potential side charging switch DCRH and a positive side connecting portion are provided at a position closer to the first battery 31 than the high potential side main switch SMRH, and in the low potential side electrical path 22L, a low potential side charging switch DCRL and a negative side connecting portion are provided at a position closer to the second battery 32 than the low potential side main switch SMRL.

[0125] The positive terminal of the first storage battery 31 and the high potential side electric path 22H may be connected via a first fuse. In addition, the negative terminal of the second storage battery 32 and the low potential side electric path 22L may be connected via a second fuse.

[0126] Each main switch SMRH, SMRL, each charging switch DCRH, DCRL, inter-battery switch 40, bypass switch and motor-side 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.

[0127] 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.

[0128] 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.

[0129] 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.

[0130] 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. Furthermore, the installation location of the power conversion device is not limited to a mobile object, and may be a stationary device.

[0131] ·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.

[0132] 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 a positive terminal of the first power storage unit (31) and a positive terminal of an external charger (200, 210); a low potential side electrical path (22L) capable of being electrically connected to the negative terminal of the second power storage unit (32) and the negative terminal of the external charger; 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) has an armature winding (11) 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 starts charging at least one of the first power storage unit and the second power storage unit by the external charger in a state where the switch between power storage units is turned off and the bypass switch is turned on. After charging by the external charger starts, a process of switching the inverter, that is, a voltage adjustment process, is performed so that the voltage difference between the first power storage unit and the second power storage unit becomes equal to or less than a determination threshold.

2. The power conversion device according to claim 1, 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 is a path (25 to 27) that electrically connects the armature winding and a position of the inter-power storage unit electrical path that is closer to the second power storage unit than the inter-power storage unit switch.

3. The power conversion device according to claim 2, characterized in that: The voltage adjustment process is a process of switching the inverter so as to make the voltage difference equal to or less than the determination threshold value and to make the voltage of the first power storage unit equal to or greater than the voltage of the second power storage unit.

4. The power conversion device according to claim 3, characterized in that: The control unit, before executing the voltage regulation process, when it is determined that the voltage of the first power storage unit is lower than a value obtained by subtracting the determination threshold from the voltage of the second power storage unit, performs the following pre-charging process in a state where the switch between the power storage units is turned off and the bypass switch between the negative electrodes is turned on: only the first power storage unit of the first power storage unit and the second power storage unit is charged by the external charger in a manner such that the voltage difference is less than the determination threshold.

5. The power conversion device according to claim 3, characterized in that: Before executing the voltage regulation process, when the control unit determines that the voltage of the second power storage unit is lower than a value obtained by subtracting the determination threshold from the voltage of the first power storage unit, the control unit performs the following pre-charging process in a state where the switch between power storage units and the bypass switch between negative electrodes are turned off and the upper arm switch is turned on: only the second power storage unit of the first power storage unit and the second power storage unit is charged by the external charger in a manner such that the voltage difference is less than the determination threshold.

6. The power conversion device according to claim 3, characterized in that: Before executing the voltage regulation process, when the control unit determines that the voltage of the second power storage unit is lower than the voltage of the first power storage unit, or the voltage difference between the first power storage unit and the second power storage unit is below the determination threshold, the control unit performs the following pre-charging process with the switch between the power storage units turned off and the negative electrode bypass switch turned on: the inverter is opened and closed while the charging current is output from the external charger in such a manner that the charging power of the second power storage unit is greater than that of the first power storage unit and the voltage difference is below the determination threshold.

7. The power conversion device according to any one of claims 4 to 6, characterized in that: The control unit outputs a charging current from the external charger during a charging control period from a charging start time to a charging end time, The pre-charging process is performed during a period earlier than a specific time between the charging start time and the charging end time in the charging control period. The voltage regulation process during the period after the specific time in the charging control period is a switching process of the inverter that makes the charging power of the second power storage unit larger than the charging power of the first power storage unit in such a way that the voltage difference at the charging end time is smaller than the voltage difference at the specific time.

8. The power conversion device according to claim 7, characterized in that: The specific time is a time when the charging power output from the external charger to the first power storage unit becomes larger than the allowable charging power for the first power storage unit.

9. The power conversion device according to claim 7, characterized in that: The specific time is the time when the charging mode of the external charger is switched from the constant current mode to the constant voltage mode or the constant power mode.

10. The power conversion device according to claim 7, characterized in that: The specific time is a time before a predetermined period from the charging end time.

11. The power conversion device according to claim 7, characterized in that: The specific time is a time when the current charging rate of the first power storage unit becomes a value obtained by subtracting a predetermined charging rate from the target charging rates of the first power storage unit and the second power storage unit at the charging end time.

12. The power conversion device according to claim 1, 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 is a path (25, 26, 28) that electrically connects the armature winding and a position of the inter-electrical path of the electric path closer to the first electric storage unit than the inter-electrical storage unit switch.

13. The power conversion device according to claim 12, characterized in that: The voltage adjustment process is a process of switching the inverter so as to make the voltage difference equal to or less than the determination threshold value and to make the voltage of the second power storage unit equal to or greater than the voltage of the first power storage unit.

14. The power conversion device according to claim 13, characterized in that: Before executing the voltage regulation process, when the control unit determines that the voltage of the second power storage unit is lower than a value obtained by subtracting the determination threshold from the voltage of the first power storage unit, the control unit performs the following pre-charging process in a state where the switch between the power storage units is turned off and the bypass switch between the positive electrodes is turned on: only the second power storage unit of the first power storage unit and the second power storage unit is charged by the external charger in a manner such that the voltage difference is less than the determination threshold.

15. The power conversion device according to claim 13, characterized in that: Before executing the voltage regulation process, when the control unit determines that the voltage of the first storage unit is lower than the value obtained by subtracting the determination threshold from the voltage of the second storage unit, the control unit performs the following pre-charging process in a state where the switch between storage units and the bypass switch between positive electrodes are disconnected and the lower arm switch is turned on: only the first storage unit of the first storage unit and the second storage unit is charged by the external charger in a manner that makes the voltage difference less than the determination threshold.

16. The power conversion device according to claim 13, characterized in that: Before executing the voltage regulation process, when the control unit determines that the voltage of the first storage unit is lower than the voltage of the second storage unit, or the voltage difference between the second storage unit and the first storage unit is below the determination threshold, the control unit performs the following pre-charging process with the switch between the storage units turned off and the bypass switch between the positive electrodes turned on: the inverter is opened and closed while the charging current is output from the external charger in such a manner that the charging power of the first storage unit is greater than that of the second storage unit and the voltage difference is below the determination threshold.

17. The power conversion device according to any one of claims 14 to 16, characterized in that: The control unit outputs a charging current from the external charger during a charging control period from a charging start time to a charging end time, The pre-charging process is performed during a period earlier than a specific time between the charging start time and the charging end time in the charging control period. The voltage regulation process during the period after the specific time in the charging control period is a switching process of the inverter so that the charging power of the first storage unit is larger than the charging power of the second storage unit in such a manner that the voltage difference at the charging end time is smaller than the voltage difference at the specific time.

18. The power conversion device according to claim 17, characterized in that: The specific time is a time at which the charging power output from the external charger to the second power storage unit is greater than the allowable charging power for the second power storage unit.

19. The power conversion device according to claim 17, characterized in that: The specific time is the time when the charging mode of the external charger is switched from the constant current mode to the constant voltage mode or the constant power mode.

20. The power conversion device according to claim 17, characterized in that: The specific time is a time before a predetermined period from the charging end time.

21. The power conversion device according to claim 17, characterized in that: The specific time is a time when the current charging rate of the second power storage unit becomes a value obtained by subtracting a predetermined charging rate from the target charging rates of the first power storage unit and the second power storage unit at the charging end time.

22. A program for use in a power conversion device, the power conversion device comprising: A high potential side electrical path (22H) capable of being electrically connected to a positive terminal of the first power storage unit (31) and a positive terminal of an external charger (200, 210); a low potential side electrical path (22L) capable of being electrically connected to the negative terminal of the second power storage unit (32) and the negative terminal of the external charger; 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; A motor (10) having an armature winding (11) 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: In a state where the switch between the power storage units is turned off and the bypass switch is turned on, the external charger starts charging at least one of the first power storage unit and the second power storage unit; as well as After charging by the external charger starts, a process of switching the inverter, that is, a voltage adjustment process, is performed so that the voltage difference between the first power storage unit and the second power storage unit becomes equal to or less than a determination threshold.

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