Power conversion device and program

Abstract

To provide a power conversion device and program that can maintain a rotor's rotation stopped state.SOLUTION: The power conversion device includes an inverter 20 having upper and lower arm switches SUH to SWL, a motor 10, a battery inter-switch 50, a bypass switch 60, a connection path 73, and a motor ECU 100. The motor ECU 100 performs switching control of the inverter 20 to make a current to flow through the connection path 73 under the condition that the torque generated by the motor 10 is a torque that can maintain a rotor 13 of the motor 10 in a rotation stopped state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a power conversion device and a program. [Background technology]

[0002] Conventionally, a power conversion device including an inverter and a motor electrically connected to the inverter is known. The inverter has upper and lower arm switches of multiple phases. The armature winding is electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase. Note that a technology related to such a power conversion device is described in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-47677 A Summary of the Invention [Problem to be solved by the invention]

[0004] There is still room for improvement in technology for properly controlling inverter switching.

[0005] A primary object of the present disclosure is to provide a power converter control device and a program that can appropriately control the switching of an inverter. [Means for solving the problem]

[0006] The present disclosure provides an inverter having upper and lower arm switches for multiple phases; a motor having an armature winding electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a rotor; In a power conversion device comprising: a high potential side path electrically connecting a positive electrode terminal of the first power storage unit and a high potential side terminal of the upper arm switch; a low potential side path electrically connecting a negative electrode terminal of the second power storage unit and a low potential side terminal of the lower arm switch; an inter-power storage unit switch that, when turned on, electrically connects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit and, when turned off, electrically disconnects the negative electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit; a bypass switch that electrically connects negative electrode terminals of the first power storage unit and the second power storage unit to each other and electrically connects positive electrode terminals of the first power storage unit and the second power storage unit to each other; a connection path electrically connecting the negative terminal of the first power storage unit or the positive terminal of the second power storage unit to the armature winding; The motor is equipped with a control device that performs switching control of a target switch, which is at least one of the upper and lower arm switches, so as to flow current through the connection path under the condition that the torque generated by the motor is a torque capable of maintaining the rotor in a stopped state.

[0007] The power conversion device of the present disclosure includes a high-potential side path, a low-potential side path, an inter-storage unit switch, a bypass switch, and a connection path. With this configuration, a control device executes switching control of a target switch, which is at least one of the upper and lower arm switches, so that a current flows through the connection path.

[0008] In addition, the control device of the present disclosure performs switching control of the target switch to pass a current through the connection path under the condition that the torque generated by the motor is a torque that can maintain the rotor in a rotation stopped state. This makes it possible to perform appropriate switching control that maintains the rotor in a rotation stopped state when passing a current through the connection path. [Brief description of the drawings]

[0009] [Figure 1] 1 is an overall configuration diagram of a system according to a first embodiment. [Diagram 2] FIG. 4 is a diagram showing the control state of the switches during high voltage charging. [Diagram 3] FIG. 4 is a diagram showing the control state of the switches during low-voltage charging. [Figure 4] 4 is a flowchart showing a procedure of an external charging control process. [Diagram 5] A diagram showing the dq coordinate system. [Figure 6] FIG. 13 is a diagram showing a calculation result of a relationship between a current phase and a torque. [Figure 7] 10 is a time chart showing a control mode of a q-axis current according to the second embodiment. [Figure 8] 13 is a flowchart showing a procedure of an external charging control process according to a third embodiment. [Figure 9] Calculation results showing the relationship between the electrical angle and d-axis current when current flow to the U phase is stopped. [Figure 10] Calculation results showing the relationship between the electrical angle and d-axis current when V-phase current is stopped. [Figure 11] Calculation results showing the relationship between the electrical angle and d-axis current when the W-phase current is stopped. [Figure 12] FIG. 13 is a diagram showing a control state of a switch during high voltage power supply according to the fourth embodiment. [Figure 13] FIG. 4 is a diagram showing the control state of the switch during low voltage power supply. [Figure 14] FIG. 13 is a diagram showing a control state of a switch during equalization control according to the fifth embodiment. [Figure 15] FIG. 13 is an overall configuration diagram of a system according to a sixth embodiment. [Figure 16] FIG. 4 is a diagram showing the control state of the switches during low-voltage charging. [Figure 17] FIG. 4 is a diagram showing the control state of the switch during low voltage power supply. [Figure 18] FIG. 4 is a diagram showing a control state of a switch during equalization control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Several embodiments will be described with reference to the drawings. In several embodiments, functionally and / or structurally corresponding and / or associated parts may be given the same reference numerals or reference numerals with different digits of 100 or more. For corresponding and / or associated parts, the description of other embodiments may be referred to.

[0011] First Embodiment A first embodiment of a power conversion device according to the present invention will now be described with reference to the drawings. The power conversion device of the present embodiment is mounted on a vehicle such as an electric vehicle or a hybrid vehicle to form an on-board system.

[0012] As shown in Fig. 1, the power conversion device includes a motor 10, an inverter 20, a high-potential side path 22H, and a low-potential side path 22L. The motor 10 is a three-phase synchronous machine, and includes star-connected armature windings 11 of U, V, and W phases, and a rotor 13. The armature windings 11 of each phase are arranged with an electrical angle of 120°. The motor 10 is, for example, a permanent magnet synchronous machine. The rotor 13 is capable of transmitting power to the drive wheels of the vehicle. Therefore, the motor 10 serves as a source of torque for running the vehicle.

[0013] The inverter 20 includes three phases of series-connected upper and lower arm switches. More specifically, the inverter 20 includes U-, V-, and W-phase upper arm switches SUH, SVH, and SWH, and U-, V-, and W-phase lower arm switches SUL, SVL, and SWL. The U-, V-, and W-phase upper arm diodes DUH, DVH, and DWH, which are freewheel diodes, are connected in inverse parallel to the U-, V-, and W-phase upper arm switches SUH, SVH, and SWH, and the U-, V-, and W-phase lower arm diodes DUL, DVL, and DWL, which are freewheel diodes, are connected in inverse parallel to the U-, V-, and W-phase lower arm switches SUL, SVL, and SWL. In this embodiment, the switches SUH, SVH, SWH, SUL, SVL, and SWL are IGBTs.

[0014] The inverter 20 includes a smoothing capacitor 21. A long high potential side path 22H is connected to a high potential side terminal of the smoothing capacitor 21. A long low potential side path 22L is connected to a low potential side terminal of the smoothing capacitor 21. The high potential side path 22H and the low potential side path 22L are, for example, electrical paths such as bus bars. The smoothing capacitor 21 may be provided outside the inverter 20.

[0015] First ends of the U-, V-, and W-phase armature windings 11U, 11V, and 11W are connected to a connection point between emitters, which are low potential terminals of the U-, V-, and W-phase upper arm switches SUH, SVH, and SWH, and collectors, which are high potential terminals of the U-, V-, and W-phase lower arm switches SUL, SVL, and SWL, via conductive members 23 such as bus bars. Second ends of the U-, V-, and W-phase armature windings 11U, 11V, and 11W are connected to each other at a neutral point O. In this embodiment, the U-, V-, and W-phase armature windings 11U, 11V, and 11W are set to have the same number of turns. As a result, the U-, V-, and W-phase armature windings 11U, 11V, and 11W are set to have the same inductance, for example.

[0016] A high potential side path 22H is connected to the collectors of the U-, V-, and W-phase upper arm switches SUH, SVH, and SWH. A low potential side path 22L is connected to the emitters of the U-, V-, and W-phase lower arm switches SUL, SVL, and SWL.

[0017] The system includes a first storage battery 31 (corresponding to a "first power storage unit") and a second storage battery 32 (corresponding to a "second power storage unit"). Each of the storage batteries 31, 32 is a power supply source for rotating and driving the rotor 13 of the motor 10. Each of the storage batteries 31, 32 is a battery pack including a series connection of a plurality of unit batteries. The unit battery is a single battery cell that is a single cell, or a series connection of a plurality of battery cells. In this embodiment, the full charge capacity (specifically, for example, rated full charge capacity) [Ah] of each of the unit batteries constituting the first storage battery 31 and the second storage battery 32 is the same. The positive terminal of the first storage battery 31 is connected to the high potential side path 22H via the first fuse 41, and the negative terminal of the second storage battery 32 is connected to the low potential side path 22L via the second fuse 42. The terminal voltages (for example, rated voltages) of each of the battery cells constituting the battery pack are set to be the same, for example. The battery cells are, for example, secondary batteries such as lithium ion batteries. In this embodiment, the terminal voltage (e.g., rated voltage) of the first storage battery 31 is higher than the terminal voltage (e.g., rated voltage) of the second storage battery 32. This configuration can be realized, for example, by making the number of unit batteries constituting the first storage battery 31 greater than the number of unit batteries constituting the second storage battery 32.

[0018] 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. More specifically, a high-side main switch SMRH, a low-side main switch SMRL, and a pre-charge main switch SMRP are provided as the main switches. In this embodiment, the main switches SMRH, SMRL, and SMRP are mechanical relays. When the main switches SMRH, SMRL, and SMRP are turned off, they block the flow of current in both directions, and when they are turned on, they allow the flow of current in both directions. The high-side main switch SMRH is provided on the high-side path 22H, and the low-side main switch SMRL is provided on the low-side path 22L. A series connection of the pre-charge main switch SMRP and the pre-charge resistor 40 is connected in parallel to the low-side main switch SMRL. The main switches SMRH, SMRL, and SMRP are not limited to mechanical relays, and may be, for example, semiconductor switching elements.

[0019] Each of the storage batteries 31, 32 can be charged by an external charger provided outside the vehicle through external charging control. The external charger is, for example, a stationary charger.

[0020] Each of the storage batteries 31 and 32 can supply power to a power supply target unit outside the vehicle through external power supply control. When the power supply target unit is a system power source, the external power supply control is also called V2G (Vehicle to Grid). When the power supply target unit is an electrical device in a building such as a residence, the external power supply control is also called V2H (Vehicle to Home).

[0021] The power conversion device includes a high-potential side connection switch DCRH and a low-potential side connection switch DCRL for electrically connecting or disconnecting an external charger or a power supply target unit and the first and second storage batteries 31 and 32. In this embodiment, each of the connection switches DCRH and DCRL is a mechanical relay. When each of the connection switches DCRH and DCRL is turned off, it blocks bidirectional current flow, and when each of the connection switches DCRH and DCRL is turned on, it allows bidirectional current flow. The high-potential side connection switch DCRH is provided in a portion of the high-potential side path 22H that is closer to the inverter 20 than the high-potential side main switch SMRH. The low-potential side connection switch DCRL is provided in a portion of the low-potential side path 22L that is closer to the inverter 20 than the low-potential side main switch SMRL. Note that each of the connection switches DCRH and DCRL is not limited to a mechanical relay, and may be, for example, a semiconductor switching element.

[0022] The power conversion device includes an inter-battery switch 50 (corresponding to an "inter-power storage unit switch"), a bypass switch 60, a first motor-side switch 71, a second motor-side switch 72, and a connection path 73 as components for switching the connection state of the first storage battery 31 and the second storage battery 32. In this embodiment, the inter-battery switch 50, the bypass switch 60, and each of the motor-side switches 71, 72 are mechanical relays. When the inter-battery switch 50, the bypass switch 60, and each of the motor-side switches 71, 72 are turned off, they block the flow of bidirectional current, and when they are turned on, they allow the flow of bidirectional current. Note that the inter-battery switch 50, the bypass switch 60, and each of the motor-side switches 71, 72 are not limited to mechanical relays, and may be, for example, semiconductor switching elements.

[0023] The inter-battery switch 50 connects the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32. When the inter-battery switch 50 is turned on, 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, when the inter-battery switch 50 is turned off, the negative terminal of the first storage battery 31 and the positive terminal of the second storage battery 32 are electrically disconnected.

[0024] The bypass switch 60 connects the negative terminal of the first storage battery 31 and the low potential side path 22L. When the bypass switch 60 is turned on, the negative terminal of the first storage battery 31 and the negative terminal of the second storage battery 32 are electrically connected to each other. On the other hand, when the bypass switch 60 is turned off, the negative terminal of the first storage battery 31 and the negative terminal of the second storage battery 32 are electrically disconnected from each other.

[0025] In this embodiment, the first storage battery 31 and the second storage battery 32 configure a battery unit 30.

[0026] The connection path 73 is an electrical path that connects the positive terminal of the second storage battery 32 and the neutral point O. A first motor-side switch 71 and a second motor-side switch 72 are provided in this order from the second storage battery 32 on the connection path 73.

[0027] The power conversion device includes a neutral point capacitor 74 that is a capacitor that connects the connection path 73 and the low potential side path 22L. A first end of the neutral point capacitor 74 is connected to a portion of the connection path 73 between the first motor side switch 71 and the second motor side switch 72. A second end of the neutral point capacitor 74 is connected to a portion of the low potential side path 22L that is closer to the inverter 20 than the low potential side main switch SMRL and the pre-charge main switch SMRP.

[0028] By turning on the first motor side switch 71, the first end of the neutral point capacitor 74 and the positive terminal of the second storage battery 32 are electrically connected. On the other hand, by turning off the first motor side switch 71, the first end of the neutral point capacitor 74 and the positive terminal of the second storage battery 32 are electrically disconnected. By turning on the second motor side switch 72, the neutral point O of the armature winding 11 and the first end of the neutral point capacitor 74 are electrically connected. On the other hand, by turning off the second motor side switch 72, the neutral point O and the first end of the neutral point capacitor 74 are electrically disconnected.

[0029] The power conversion device includes a first current sensor 81A, a second current sensor 81B, a phase current sensor 82, and a motor current sensor 83 as current sensors for detecting currents flowing through various parts of the power conversion device. The first current sensor 81A detects a current flowing through the first storage battery 31, and the second current sensor 81B detects a current flowing through the second storage battery 32. The phase current sensor 82 detects a current flowing through the U-, V-, and W-phase armature windings 11U, 11V, and 11W. The motor current sensor 83 detects a current flowing through the connection path 73, and in this embodiment, detects a current flowing through a portion of the connection path 73 that is closer to the neutral point O than the connection point with the neutral point capacitor 74.

[0030] The power conversion device includes a capacitor voltage sensor 84 that detects the terminal voltage of the neutral point capacitor 74, a first voltage sensor 85A that detects the terminal voltage of the first storage battery 31, and a second voltage sensor 85B that detects the terminal voltage of the second storage battery 32. The power conversion device also includes a power supply voltage sensor 86 that detects the terminal voltage of the smoothing capacitor 21, and a rotation angle sensor 87 that detects the rotation angle (electrical angle) of the rotor 13.

[0031] The system includes a battery ECU 90 that controls the battery unit 30, a motor ECU 100 that controls the inverter 20, and an EVECU 110 that manages the system. The battery ECU 90 is an electronic control unit mainly composed of a microcomputer 91. The motor ECU 100 is an electronic control unit mainly composed of a microcomputer 101. The EVECU 110 is an electronic control unit mainly composed of a microcomputer 111, and is a higher-level control unit than the battery ECU 90 and the motor ECU 100. The battery ECU 90 and the motor ECU 100 are able to exchange information via the EVECU 110.

[0032] Each of the microcomputers 91, 101, and 111 includes a CPU (Central Processing Unit). The functions provided by each of the microcomputers 91, 101, and 111 can be provided by software recorded in a substantial memory device and a computer that executes the software, by software alone, by hardware alone, or by a combination of these. For example, when each of the microcomputers 91, 101, and 111 is provided by an electronic circuit that is hardware, the function can be provided by a digital circuit including a large number of logic circuits, or by an analog circuit. For example, each of the microcomputers 91, 101, and 111 executes a program stored in a non-transitory tangible storage medium as a storage unit provided in the microcomputer. The program includes, for example, a program of a process shown in FIG. 4, which will be described later. A set of instructions that constitute the program is executed, thereby executing a method corresponding to the program. The storage unit is, for example, a non-volatile memory. The program stored in the storage unit can be updated via a communication network such as the Internet, for example, OTA (Over The Air), etc.

[0033] Detection values ​​of a first current sensor 81A, a second current sensor 81B, a first voltage sensor 85A, and a second voltage sensor 85B are input to the battery ECU 90. Detection values ​​of a phase current sensor 82, a motor current sensor 83, a capacitor voltage sensor 84, a power supply voltage sensor 86, and a rotation angle sensor 88 are input to the motor ECU 100.

[0034] The motor ECU 100 performs switching control of the upper and lower arm switches SUH-SWL of each phase constituting the inverter 20 to feedback control the control amount of the motor 10 to a command value based on the detection values ​​of each sensor. The control amount is, for example, torque. In each phase, the upper arm switch and the lower arm switch are alternately turned on. Through this feedback control, the rotational power of the rotor 13 of the motor 10 is transmitted to the drive wheels, causing the vehicle to run.

[0035] The main switches SMRH, SMRL, SMRP, the inter-battery switch 50, the bypass switch 60, and the motor-side switches 71, 72 may be controlled by any one of the battery ECU 90, the motor ECU 100, or the EVECU 110, or may be controlled by an ECU other than the ECUs 90, 100, 110. In this embodiment, hereinafter, the main switches SMRH, SMRL, SMRP, the inter-battery switch 50, the bypass switch 60, and the motor-side switches 71, 72 are assumed to be controlled by the motor ECU 100.

[0036] Next, the external charging control will be described.

[0037] In this embodiment, the external charger is a high-voltage charger 200 or a low-voltage charger 210, as shown in Figs. 2 and 3. The charging voltage of the high-voltage charger 200 is higher than the terminal voltage (specifically, the rated voltage) of the series-connected body of the first and second storage batteries 31 and 32, and is, for example, 800V. The charging voltage of the low-voltage charger 210 is lower than the terminal voltage of the series-connected body of the first and second storage batteries 31 and 32 and higher than the terminal voltage (specifically, the rated voltage) of the first storage battery 32, and is, for example, 400V. When the first and second storage batteries 31 and 32 are charged by the external charger, the high-potential side connection switch DCRH and the low-potential side connection switch DCRL are switched on. On the other hand, when charging by the external charger is not performed or when the external charger is not connected to the power conversion device, the high-potential side connection switch DCRH and the low-potential side connection switch DCRL are switched off.

[0038] 2 shows the control state of each switch during external charging control using the high-voltage charger 200. The high-voltage charger 200 and the power conversion device are electrically connected when the charging plug of the high-voltage charger 200 is electrically connected to each connection switch DCRH, DCRL by the vehicle user. When the motor ECU 100 determines that the external charger connected to the power conversion device is the high-voltage charger 200, it turns off the pre-charge main switch SMRP, the bypass switch 60, the first motor side switch 71, the second motor side switch 72, and the upper and lower arm switches SUH to SWL of all phases of the inverter 20, and turns on the high potential side main switch SMRH, the low potential side main switch SMRL, and the inter-battery switch 50. As a result, the first storage battery 31 and the second storage battery 32 are connected in series to the high-voltage charger 200. As a result, a current flows through a closed circuit including the high-voltage charger 200, the high-potential side path 22H, the first storage battery 31, the inter-battery switch 50, the second storage battery 32, and the low-potential side path 22L, and the first storage battery 31 and the second storage battery 32 are charged in a state of being connected in series. At this time, since the upper arm switches SUH, SVH, SWH of the inverter 20 and the second motor-side switch 72 are turned off, it is possible to prevent the charging current of the high-voltage charger 200 from flowing to the inverter 20 and the armature winding 11.

[0039] 3 shows the control state of each switch during external charging control using the low-voltage charger 210. The low-voltage charger 210 and the power conversion device are electrically connected by electrically connecting the charging plug of the low-voltage charger 210 to each connection switch DCRH, DCRL by the vehicle user. When the motor ECU 100 determines that the external charger connected to the power conversion device is the low-voltage charger 210, it turns off the pre-charge main switch SMRP and the inter-battery switch 50, and turns on the high-potential side main switch SMRH, the low-potential side main switch SMRL, the bypass switch 60, the first motor side switch 71, and the second motor side switch 72. As a result, a current flows through a closed circuit including the low-voltage charger 210, the high-potential side path 22H, the first storage battery 31, the bypass switch 60, and the low-potential side path 22L, and the first storage battery 31 is charged.

[0040] In the external charging control by the low-voltage charger 210, the motor ECU 100 performs switching control to alternately turn on upper and lower arm switches (corresponding to "target switches") of at least one phase, or performs switching control of an upper arm switch (corresponding to "target switch") of at least one phase with the lower arm switches SUL, SVL, and SWL of all phases of the inverter 20 turned off, thereby stepping down the output voltage of the low-voltage charger 210 and supplying it to the second storage battery 32. In detail, the motor ECU 100 performs step-down control, which is the above-mentioned switching control for controlling the voltage detected by the capacitor voltage sensor 84 (hereinafter, neutral point capacitor voltage VN) to a target charging voltage. As a result, a current flows through a closed circuit including the low-voltage charger 210, the high potential side path 22H, the upper arm switch of the inverter 20, the armature winding 11, the neutral point O, the second motor side switch 72, the first motor side switch 71, the second storage battery 32, and the low potential side path 22L, and the second storage battery 32 is charged. Since the terminal voltage of the second storage battery 32 is lower than the terminal voltage of the first storage battery 31 , the target charging voltage of the second storage battery 32 is lower than the target charging voltage of the first storage battery 31 .

[0041] 4 is a flowchart showing the procedure of an external charging control process of the low-voltage charger 210. This process is repeatedly executed by the motor ECU 100, for example, at a predetermined control period.

[0042] In step S10, a command charging current IN*, which is a command value for the charging current of the second storage battery 32, is calculated.

[0043] In steps S11 to S15, the number of phases of the inverter 20 that are switching-controlled in the external charging control is reduced as the calculated command charging current IN* is reduced. This is to increase the charging efficiency of the second storage battery 32.

[0044] In other words, the smaller the charging current of the second storage battery 32 flowing through the connection path 73, the less likely it is that a large current (e.g., overcurrent) will flow through the switches of the inverter 20 that are switching-controlled, even if the number of phases of the inverter 20 for which switching control is performed is reduced. Reducing the number of phases of the switches that are switching-controlled reduces the number of phases of the freewheel diodes through which recovery current flows, among the freewheel diodes of each phase that constitutes the inverter 20, reducing the switching loss of the inverter 20 and ultimately improving the charging efficiency.

[0045] In step S11, it is determined whether the calculated command charging current IN* is greater than the first threshold IthH. If the determination in step S11 is affirmative, the process proceeds to step S12, where three phases are selected as the number of phases of the inverter 20 to be switched. That is, in this case, the phases of the inverter 20 to be switched are the U, V, and W phases.

[0046] In step S16, the calculated command charging current IN* is divided by 3, which is the number of phases selected in step S12, to calculate U-, V-, and W-phase individual command currents Iu*, Iv*, and Iw* (=IN* / 3) which are command values ​​of the charging currents to be passed through the U-, V-, and W-phase armature windings 11U, 11V, and 11W. Then, for each of the U-, V-, and W-phases, a duty signal Duty is calculated for controlling the detected current of the phase current sensor 82 to the individual command current. Taking the U-phase as an example, the duty signal Duty is a signal indicating the ratio (=Ton / Tsw) of the on-period Ton of the U-phase upper arm switch SUH to one switching period Tsw.

[0047] In step S17, gate signals for the upper and lower arm switches are generated based on the calculated duty signal Duty for each of the U, V, and W phases. In step S18, step-down control of the inverter 20 is performed based on the generated gate signals for each of the U, V, and W phases. As a result, the currents flowing through the U, V, and W phase armature windings 11U, 11V, and 11W are controlled to the individual command currents, and the currents flowing through the connection path 73 and the second storage battery 32 are controlled to the command charging current IN*.

[0048] When it is determined in step S11 that the commanded charging current IN* is less than or equal to the first threshold IthH, the process proceeds to step S13. In step S13, it is determined whether the commanded charging current IN* is less than or equal to the first threshold IthH and greater than the second threshold IthL (<IthH).

[0049] If the determination in step S13 is affirmative, the process proceeds to step S14, and two phases are selected as the number of phases of the inverter 20 that is under switching control. That is, in this case, the phases of the inverter 20 that is under switching control are any two of the U, V, and W phases. Hereinafter, for the sake of convenience, it is assumed that the U and V phases are selected.

[0050] In step S16, the calculated commanded charging current IN* is divided by 2, which is the number of phases selected in step S14, to calculate the U- and V-phase individual commanded currents Iu*, Iv* (=IN* / 2). Note that the W-phase individual commanded current Iw* is 0.

[0051] Then, for each of the U and V phases, a duty ratio signal Duty for controlling the detected current of the phase current sensor 82 to the individual commanded current is calculated. In step S17, for each of the U and V phases, gate signals for the upper and lower arm switches are generated based on the calculated duty ratio signal Duty. In step S18, for each of the U and V phases, step-down control of the inverter 20 is performed based on the generated gate signals. As a result, the currents flowing through the U- and V-phase armature windings 11U, 11V are controlled to the individual commanded currents, and thus the currents flowing through the connection path 73 and the second storage battery 32 are controlled to the commanded charging current IN*.

[0052] When it is determined in step S12 that the commanded charging current IN* is less than or equal to the second threshold IthL, the process proceeds to step S15. In step S15, one phase is selected as the number of phases of the inverter 20 that is under switching control. That is, in this case, the phases of the inverter 20 that is under switching control are any one of the U, V, and W phases. Hereinafter, for the sake of convenience, it is assumed that the U phase is selected.

[0053] In step S16, the calculated command charging current IN* is calculated as a U-phase individual command current Iu*. Note that the V- and W-phase individual command currents Iv* and Iw* are 0. Then, for the U-phase, a duty signal Duty is calculated for controlling the detection current of the phase current sensor 82 to the individual command current. In step S17, gate signals for the U-phase upper and lower arm switches SUH and SUL are generated based on the calculated duty signal Duty. In step S18, step-down control of the inverter 20 is performed based on the generated gate signal. As a result, the current flowing through the U-phase armature winding 11U is controlled to the individual command current, and thus the current flowing through the connection path 73 and the second storage battery 32 is controlled to the command charging current IN*.

[0054] In this embodiment, the motor ECU 100 performs a characteristic process for maintaining the rotor 13 in a rotation-stopped state during external charging control. This process will be described below with reference to Figs. 5 and 6. Fig. 5 is a diagram showing a dq coordinate system. Fig. 5 shows equal torque lines, a current vector Ivtr flowing through the armature windings 11U to 11W of the motor 10, an MTPA line, and a current limit circle that is an upper limit value of the magnitude of the current vector Ivtr. The MTPA line is a line determined by a combination of d-axis and q-axis currents Id and Iq for minimum current maximum torque control. The current vector Ivtr is determined by the d-axis current Id and the q-axis current Iq. In the dq coordinate system, the negative side of the d-axis is a field-weakening region.

[0055] As shown in FIG. 5, the angle between the positive d-axis of the dq coordinate system and the current vector Ivtr is defined as the current phase β. The sign of the current phase β is positive when the current vector Ivtr rotates counterclockwise with respect to the positive d-axis of the dq coordinate system. FIG. 6 shows a calculation result showing the relationship between the current phase β and the torque generated by the motor 10. In FIG. 6, the lower horizontal axis shows the range of the current phase β of "0°≦β≦+180°" and "-180°≦β≦0°", and the upper horizontal axis shows the range of the current phase β of "0°≦β≦+360°". Since the motor 10 of this embodiment has a reverse saliency characteristic in which the q-axis inductance Lq is larger than the d-axis inductance Ld, this calculation result is for the case of reverse saliency. In this calculation, the electrical angular velocity ωe is set to 0. In this case, the d- and q-axis voltages Vd and Vq applied to the armature winding are "Vd=Ra×Id, Vq=Ra×Iq". Ra is the resistance of the armature winding.

[0056] In FIG. 6, line A is a calculation result of the current phase β and torque when the magnitude of the current vector Ivtr is set to the upper limit value (i.e., when the current vector Ivtr is located on the current limit circle). On line A, the maximum positive and negative values ​​(+100%, -100%) are the torque when the current vector Ivtr is located on the MTPA line, and are the maximum generated torque of the motor 10. The positive torque is a torque that tries to rotate the rotor 13 in a first direction to move the vehicle forward. The negative torque is a torque that tries to rotate the rotor 13 in a second direction that is opposite to the first direction. The vertical axis of FIG. 6 indicates the ratio when the maximum generated torque is ±100%. When the current vector Ivtr is located on the MTPA line with the q-axis current being positive, "β≈+135°", and when the current vector Ivtr is located on the MTPA line with the q-axis current being negative, "β≈-135°, 225°". Line B is the calculation result when the magnitude of the current vector Ivtr is made smaller than in the case of line A.

[0057] The motor ECU 100 generates a gate signal and performs step-down control of the inverter 20 so that the magnitude of the current phase β is 45° or less with respect to the positive d-axis, that is, so that the current phase β is an angle of -45° or more and +45° or less. The reason for setting "-45°≦β≦45°" is to keep the torque generated by the motor 10 during external charging control within approximately ±15% of the maximum generated torque.

[0058] The motor ECU 100 preferably performs step-down control of the inverter 20 by generating a gate signal so that the current phase β is at an angle of -35° or more and +35° or less. This allows the torque generated by the motor 10 during external charging control to be within ±5% of the maximum torque. In this case, the torque generated by the motor 10 is, for example, within ±20 Nm. More preferably, the motor ECU 100 performs step-down control of the inverter 20 by generating a gate signal so that the current phase β is at an angle of -10° or more and +10° or less. This allows the torque generated by the motor 10 during external charging control to be within ±3% of the maximum torque. In this case, the torque generated by the motor 10 is, for example, within ±10 Nm. More preferably, the motor ECU 100 performs step-down control of the inverter 20 by generating a gate signal so that the current phase β is 0°. In this case, the q-axis current flowing through the armature winding of the motor 10 is 0 or close to 0.

[0059] According to the present embodiment described above, the rotor 13 can be kept stopped from rotating during external charging control. In particular, the angle range of "-45°≦β≦+45°" is an angle range in which the change in the torque generated by the motor 10 relative to the change in the current phase β is small. Therefore, it is easy to reduce the torque generated by the motor 10.

[0060] <Modification of the first embodiment> The motor ECU 100 may perform step-down control of the inverter 20 by generating a gate signal so that the magnitude of the current phase β is 45° or less, that is, "135°≦β≦225°", based on the negative d-axis (β=180°) instead of the positive d-axis (β=0°). The motor ECU 100 may perform step-down control of the inverter 20 by generating a gate signal so that the magnitude of the current phase β is preferably "145°≦β≦215°", more preferably "170°≦β≦190°". When the negative d-axis is used as the reference, the motor ECU 100 may perform step-down control so that the magnitude of the angle between the negative d-axis and the current vector Ivtr is smaller than the magnitude of the angle between the current vector Ivtr and the negative d-axis when minimum current maximum torque control is performed. This can reduce the generated torque. More preferably, the motor ECU 100 may generate a gate signal so that the current phase β becomes 180° to perform step-down control of the inverter 20. In this case, the q-axis current becomes zero or close to zero.

[0061] <Second embodiment> Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the motor ECU 100 performs step-down control of the inverter 20 so that the sign of the q-axis current Iq flowing through the armature winding of the motor 10 alternates between the values ​​of the current phase β described in the first embodiment or the modified example of the first embodiment, as shown in FIG. 7(a). This alternates between the signs of the torque acting on the rotor 13, as shown in FIG. 7(b). As a result, it becomes easier to maintain the rotor 13 in a stopped state. Note that the motor ECU 100 may set the sign switching period Ts (e.g., a period of 10 msec or less) of the q-axis current Iq when the current phase β at which the torque generated by the motor 10 is relatively large (e.g., the magnitude |β| of the current phase β is 45°) to be shorter than the sign switching period Ts (e.g., a period of 100 msec or less) when the current phase β at which the torque generated by the motor 10 is relatively small (e.g., the magnitude |β| of the current phase β is 10°).

[0062] <Third embodiment> The third embodiment will be described below with reference to the drawings, focusing on the differences from the first and second embodiments. In this embodiment, when the motor ECU 100 selects two phases in the process of step S14 in Fig. 4, the motor ECU 100 performs switching control of the inverter 20 so that the q-axis current flowing through the armature winding of the motor 10 is set to zero, and only the d-axis current flows through the armature winding. This prevents the rotor 13 from rotating when external charging control is performed.

[0063] 8 is a flowchart showing the procedure of the external charging control process of the low-voltage charger 210. This process is repeatedly executed by the motor ECU 100, for example, at a predetermined control period.

[0064] If the determination in step S13 is affirmative, the process proceeds to step S20, and among the three phases, the switches of the inverter 20 for two phases in which the magnitude of the d-axis current is minimum while the q-axis current is set to zero are selected as switching control targets based on the electrical angle θe detected by the rotation angle sensor 87. By selecting the two phases in which the magnitude of the d-axis current is minimum, the charging efficiency of the second storage battery 32 in the external charging control can be improved.

[0065] Fig. 9 shows calculation results of the electrical angle θe, the d-axis current Id, the zero-phase current Iz, and the V- and W-phase currents Iv and Iw when the q-axis current is set to 0, the U-phase switching control is stopped, and the V- and W-phase switching control is performed. Fig. 10 shows calculation results of the electrical angle θe, the d-axis current Id, the zero-phase current Iz, and the U- and W-phase currents Iu and Iw when the q-axis current is set to 0, the V-phase switching control is stopped, and the U- and W-phase switching control is performed.

[0066] FIG. 11 shows calculation results of the electrical angle θe, the d-axis current Id, the zero-phase current Iz, and the U- and V-phase currents Iu and Iv when the q-axis current is set to 0, the W-phase switching control is stopped, and the U- and V-phase switching control is performed.

[0067] According to the calculation results of FIG. 9 to FIG. 11, for example, when the electrical angle θe is 3 [rad.], the magnitude of the d-axis current is smallest in the case shown in FIG. 9. That is, the magnitude of the d-axis current is smallest when the switching control of the U phase is stopped and the switching control of the V and W phases is performed. For this reason, when the motor ECU 100 determines that the electrical angle θe is 3 [rad.], it keeps the U-phase upper and lower arm switches SUH and SUL of the inverter 20 off and selects the V and W-phase switches of the inverter 20 as the switches to be subjected to switching control. Note that the motor ECU 100 may select the switches of the two phases to be subjected to switching control based on map information in which the two phases to be subjected to switching control are associated with the electrical angle θe. Note that thereafter, the process proceeds to step S17, and gate signals of the upper and lower arm switches of the two phases are generated to make the q-axis current zero and to pass only the d-axis current. Note that, when the process proceeds to step S17 via step S12 or S15, the gate signals may be generated by the method described in steps S16 and S17 of FIG. 4 above.

[0068] According to the present embodiment described above, when external charging control is performed, it is possible to increase the charging efficiency of the second storage battery 32 while suppressing the occurrence of a situation in which the rotor 13 rotates.

[0069] <Fourth embodiment> Hereinafter, the fourth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, when external power supply control is performed, the process shown in FIG.

[0070] 12 shows the control state of each switch during external power supply control in which power is supplied from the first and second storage batteries 31, 32 to the high-voltage power supply target 220. When the motor ECU 100 determines that the power supply target connected to the power conversion device is the high-voltage power supply target 220, it turns off the pre-charge main switch SMRP, the bypass switch 60, the first motor side switch 71, the second motor side switch 72, and the upper and lower arm switches SUH to SWL of all phases of the inverter 20, and turns on the connection switches DCRH, DCRL, the high-potential side main switch SMRH, the low-potential side main switch SMRL, and the inter-battery switch 50. This brings about a state in which the first storage battery 31 and the second storage battery 32 are connected in series to the high-voltage power supply target 220. As a result, current flows through a closed circuit including the first storage battery 31, the high potential side path 22H, the high voltage power supply target section 220, the low potential side path 22L and the second storage battery 32, and power is supplied from the first storage battery 31 and the second storage battery 32 to the high voltage power supply target section 220.

[0071] 13 shows the control state of each switch during external power supply control in which power is supplied from the first and second storage batteries 31 and 32 to the low-voltage power supply target 230. The rated voltage of the low-voltage power supply target 230 is lower than the rated voltage of the high-voltage power supply target 220. When the motor ECU 100 determines that the power supply target connected to the power conversion device is the low-voltage power supply target 230, it turns off the pre-charge main switch SMRP and the inter-battery switch 50, and turns on the connection switches DCRH and DCRL, the high-potential side main switch SMRH, the low-potential side main switch SMRL, the bypass switch 60, the first motor side switch 71, and the second motor side switch 72. As a result, a current flows through a closed circuit including the first storage battery 31, the high-potential side path 22H, the low-voltage power supply target 230, the low-potential side path 22L, and the bypass switch 60, and power is supplied from the first storage battery 31 to the low-voltage power supply target 230.

[0072] In the external power supply control for the low-voltage power supply target portion 230, the motor ECU 100 performs switching control for alternately turning on upper and lower arm switches (corresponding to "target switches") of at least one phase, or performs switching control for a lower arm switch (corresponding to "target switches") of at least one phase in a state in which the upper arm switches SUH, SVH, and SWH of all phases of the inverter 20 are turned off, thereby boosting the output voltage of the second storage battery 32 and supplying it to the low-voltage power supply target portion 230. In detail, the motor ECU 100 performs boost control, which is the switching control for controlling the power supply voltage VB, which is the detection voltage of the power supply voltage sensor 86, to a target power supply voltage. As a result, a current flows through a closed circuit including the second storage battery 32, the connection path 73, the armature winding 11, the inverter 20, the high potential side path 22H, the low-voltage power supply target portion 230, and the low potential side path 22L, and power is supplied from the second storage battery 32 to the low-voltage power supply target portion 230.

[0073] Next, the external power supply control according to this embodiment, which is executed by the motor ECU 100, will be described with reference to FIG.

[0074] In step S10, a command discharge current IN*, which is a command value for the discharge current of the second storage battery 32, is calculated.

[0075] In steps S11 to S15, the number of phases of the inverter 20 that are switching-controlled in the external power supply control is reduced as the calculated command discharge current IN* is smaller. More specifically, in step S11, it is determined whether the calculated command discharge current IN* is greater than a first threshold value IthH. If the determination in step S11 is affirmative, the process proceeds to step S12, where three phases are selected as the number of phases of the inverter 20 that are switching-controlled.

[0076] In step S16, the calculated command discharge current IN* is divided by 3, which is the number of phases selected in step S12, to calculate U-, V-, and W-phase individual command currents Iu*, Iv*, and Iw* (=IN* / 3) which are command values ​​of the discharge currents to be flowed through the U-, V-, and W-phase armature windings 11U, 11V, and 11W. Then, for each of the U-, V-, and W-phases, a duty signal Duty for controlling the detected current of the phase current sensor 82 to the individual command current is calculated.

[0077] In step S17, gate signals for the upper and lower arm switches are generated based on the calculated duty signal Duty for each of the U, V, and W phases. In step S18, boost control of inverter 20 is performed based on the generated gate signals for each of the U, V, and W phases. As a result, the currents flowing through U-, V-, and W-phase armature windings 11U, 11V, and 11W are controlled to individual command currents, and the current flowing through connection path 73 is controlled to command discharge current IN*.

[0078] When it is determined in step S11 that the command discharge current IN* is equal to or less than the first threshold IthH, the process proceeds to step S13. In step S13, it is determined whether the command discharge current IN* is equal to or less than the first threshold IthH and greater than the second threshold IthL.

[0079] If the determination in step S13 is affirmative, the process proceeds to step S14, where two phases are selected as the number of phases to be switched-controlled in the inverter 20. In the following, for convenience, it is assumed that the U and V phases are selected.

[0080] In step S16, the calculated command discharge current IN* is divided by 2, which is the number of phases selected in step S14, to calculate U- and V-phase individual command currents Iu* and Iv* (=IN* / 2). Note that the W-phase individual command current Iw* is 0.

[0081] Then, for each of the U and V phases, a duty signal duty is calculated for controlling the detected current of the phase current sensor 82 to an individual command current. In step S17, gate signals for the upper and lower arm switches are generated for each of the U and V phases based on the calculated duty signal duty. In step S18, boost control of the inverter 20 is performed for each of the U and V phases based on the generated gate signals. As a result, the current flowing through the U and V phase armature windings 11U, 11V is controlled to the individual command current, and ultimately the current flowing through the connection path 73 is controlled to the command discharge current IN*.

[0082] When it is determined in step S13 that the command discharge current IN* is equal to or less than the second threshold IthL, the process proceeds to step S15. In step S15, one phase is selected as the number of phases of the inverter 20 to be switched and controlled. In the following, for convenience, it is assumed that the U phase is selected.

[0083] In step S16, the calculated command discharge current IN* is calculated as the U-phase individual command current Iu*. Note that the V- and W-phase individual command currents Iv* and Iw* are 0. Then, for the U-phase, a duty signal Duty is calculated for controlling the detection current of the phase current sensor 82 to the individual command current. In step S17, gate signals for the U-phase upper and lower arm switches SUH and SUL are generated based on the calculated duty signal Duty. In step S18, boost control of the inverter 20 is performed based on the generated gate signal. As a result, the current flowing through the U-phase armature winding 11U is controlled to the individual command current, and therefore the current flowing through the connection path 73 is controlled to the command charge current IN*.

[0084] In this embodiment, the motor ECU 100 performs characteristic processing for maintaining a rotation-stop state of the rotor 13 during external power supply control. In detail, the motor ECU 100 performs boost control of the inverter 20 by generating a gate signal so that the current phase β becomes the value described in the first embodiment or the modified example of the first embodiment.

[0085] According to the present embodiment described above, the rotor 13 can be maintained in a stopped state during external power supply control.

[0086] <Fifth embodiment> Hereinafter, the fifth embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, the motor ECU 100 performs power transmission control (specifically, for example, equalization control) for transmitting power from one of the first storage battery 31 and the second storage battery 32 to the other by performing switching control of the inverter 20.

[0087] 14 shows the control state of each switch during equalization control. During equalization control, each of the connection switches DCRH and DCRL is turned off.

[0088] The motor ECU 100 turns on the high potential side main switch SMRH, the low potential side main switch SMRL, the inter-battery switch 50, the first motor side switch 71, and the second motor side switch 72, and turns off the pre-charge main switch SMRP and the bypass switch 60. The motor ECU 100 also performs switching control for at least one phase of the inverter 20 to transfer power from one of the first storage battery 31 and the second storage battery 32 to the other.

[0089] In detail, the motor ECU 100 performs a first control to supply a current from the first storage battery 31 to the second storage battery 32 via the inverter 20, the armature winding 11, and the connection path 73 by performing a step-down control for at least one phase. Also, the motor ECU 100 performs a second control to supply a current to the first storage battery 31 via the second storage battery 32, the connection path 73, the armature winding 11, and the inverter 20 by performing a step-up control for at least one phase.

[0090] By the equalization control, for example, it is possible to make the SOC of each unit battery constituting the first storage battery 31 and the SOC of each unit battery constituting the second storage battery 32 equal to each other.

[0091] The process shown in Fig. 4 can be applied even during execution of the first control or the second control. Hereinafter, the control of this embodiment executed by the motor ECU 100 will be described with reference to Fig. 4, taking the first control as an example.

[0092] In step S10, a command current IN* that is a command value of a current to be passed through the connection path 73 in order to supply power from the first storage battery 31 to the second storage battery 32 is calculated.

[0093] In steps S11 to S15, the number of phases of the inverter 20 that are switching-controlled in the equalization control is reduced as the calculated command current IN* is smaller. More specifically, in step S11, it is determined whether the calculated command current IN* is greater than a first threshold IthH. If the determination in step S11 is affirmative, the process proceeds to step S12, where three phases are selected as the number of phases of the inverter 20 that are switching-controlled.

[0094] In step S16, the calculated command current IN* is divided by 3, which is the number of phases selected in step S12, to calculate U-, V-, and W-phase individual command currents Iu*, Iv*, and Iw* (=IN* / 3), which are command values ​​for the currents to be passed through the U-, V-, and W-phase armature windings 11U, 11V, and 11W. Then, for each of the U-, V-, and W-phases, a duty signal Duty is calculated for controlling the detected currents of the phase current sensors 82 to the individual command currents.

[0095] In step S17, gate signals for the upper and lower arm switches are generated based on the calculated duty signal Duty for each of the U, V, and W phases. In step S18, step-down control of inverter 20 is performed based on the generated gate signals for each of the U, V, and W phases. As a result, the currents flowing through U-, V-, and W-phase armature windings 11U, 11V, and 11W are controlled to individual command currents, and the current flowing through connection path 73 is controlled to command current IN*.

[0096] When it is determined in step S11 that the command current IN* is equal to or less than the first threshold IthH, the process proceeds to step S13. In step S13, it is determined whether the command current IN* is equal to or less than the first threshold IthH and greater than the second threshold IthL.

[0097] If the determination in step S13 is affirmative, the process proceeds to step S14, where two phases are selected as the number of phases to be switched-controlled in the inverter 20. In the following, for convenience, it is assumed that the U and V phases are selected.

[0098] In step S16, the calculated command current IN* is divided by 2, which is the number of phases selected in step S14, to calculate U- and V-phase individual command currents Iu* and Iv* (=IN* / 2). Note that the W-phase individual command current Iw* is 0.

[0099] Then, for each of the U and V phases, a duty signal duty for controlling the detected current of phase current sensor 82 to an individual command current is calculated. In step S17, gate signals for the upper and lower arm switches are generated for each of the U and V phases based on the calculated duty signal duty. In step S18, step-down control of inverter 20 is performed for each of the U and V phases based on the generated gate signals. As a result, the current flowing through U- and V-phase armature windings 11U, 11V is controlled to the individual command current, and ultimately the current flowing through connection path 73 is controlled to command current IN*.

[0100] If it is determined in step S13 that the command current IN* is equal to or less than the second threshold IthL, the process proceeds to step S15. In step S15, one phase is selected as the number of phases of the inverter 20 to be switched and controlled. In the following, for convenience, it is assumed that the U phase is selected.

[0101] In step S16, the calculated command current IN* is calculated as a U-phase individual command current Iu*. Note that the V- and W-phase individual command currents Iv* and Iw* are 0. Then, for the U-phase, a duty signal Duty is calculated for controlling the detection current of the phase current sensor 82 to the individual command current. In step S17, gate signals for the U-phase upper and lower arm switches SUH and SUL are generated based on the calculated duty signal Duty. In step S18, step-down control of the inverter 20 is performed based on the generated gate signal. As a result, the current flowing through the U-phase armature winding 11U is controlled to the individual command current, and therefore the current flowing through the connection path 73 is controlled to the command current IN*.

[0102] In this embodiment, the motor ECU 100 performs characteristic processing for maintaining a rotation stop state of the rotor 13 during equalization control. In detail, the motor ECU 100 generates a gate signal to perform step-down control or step-up control of the inverter 20 so that the current phase β becomes the value described in the first embodiment or the modified example of the first embodiment.

[0103] According to the present embodiment described above, the rotor 13 can be maintained in a stopped state during equalization control.

[0104] Sixth embodiment The sixth embodiment will be described below with reference to the drawings, focusing on the differences from the first embodiment. In this embodiment, as shown in FIG. 15, the connection path 73 electrically connects the neutral point O of the armature winding 11 and the negative terminal of the first storage battery 31. The bypass switch 61 connects the positive terminal of the second storage battery 32 and the high potential side path 22H. The first end of the neutral point capacitor 75 is connected to a portion of the connection path 73 between the first motor side switch 71 and the second motor side switch 72. The second end of the neutral point capacitor 75 is connected to a portion of the high potential side path 22H that is closer to the inverter 20 than the high potential side main switch SMRH.

[0105] In this embodiment, the terminal voltage (for example, rated voltage) of the first storage battery 31 is lower than the terminal voltage (for example, rated voltage) of the second storage battery 32.

[0106] Next, the external charging control of this embodiment will be described. Fig. 16 shows the control state of each switch during external charging control using the low-voltage charger 210. When the motor ECU 100 determines that the external charger connected to the power conversion device is the low-voltage charger 210, it turns off the pre-charge main switch SMRP and the inter-battery switch 50, and turns on the high potential side main switch SMRH, the low potential side main switch SMRL, the bypass switch 61, the first motor side switch 71, and the second motor side switch 72. This causes the second storage battery 32 to be charged.

[0107] In the external charging control by the low-voltage charger 210, the motor ECU 100 performs switching control to alternately turn on upper and lower arm switches (corresponding to "target switches") of at least one phase, or performs switching control of a lower arm switch (corresponding to "target switches") of at least one phase with the upper arm switches SUH, SVH, SWH of all phases of the inverter 20 turned off, thereby stepping down the output voltage of the low-voltage charger 210 and supplying it to the first storage battery 31. In detail, the motor ECU 100 performs step-down control, which is the above-mentioned switching control for controlling the neutral point capacitor voltage VN to the target charging voltage. As a result, the first storage battery 31 is charged. Since the terminal voltage of the first storage battery 31 is lower than the terminal voltage of the second storage battery 32, the target charging voltage of the first storage battery 31 is lower than the target charging voltage of the second storage battery 32.

[0108] In the external charging control of this embodiment, similarly to the first embodiment, the motor ECU 100 generates a gate signal to perform step-down control of the inverter 20 so that the current phase β becomes the value described in the first embodiment or the modified example of the first embodiment. This makes it possible to maintain the rotor 13 in a rotation stopped state during the external charging control.

[0109] Next, the external power supply control of this embodiment will be described. Fig. 17 shows the control state of each switch during external power supply control in which power is supplied from the first and second storage batteries 31, 32 to the low-voltage power supply target unit 230. When the motor ECU 100 determines that the power supply target unit connected to the power conversion device is the low-voltage power supply target unit 230, it turns off the pre-charge main switch SMRP and the inter-battery switch 50, and turns on the connection switches DCRH, DCRL, the high-potential side main switch SMRH, the low-potential side main switch SMRL, the bypass switch 61, the first motor side switch 71, and the second motor side switch 72. As a result, power is supplied from the second storage battery 32 to the low-voltage power supply target unit 230.

[0110] In the external power supply control for the low-voltage power supply target portion 230, the motor ECU 100 performs switching control for alternately turning on upper and lower arm switches (corresponding to "target switches") of at least one phase, or performs switching control for an upper arm switch (corresponding to "target switches") of at least one phase in a state in which the lower arm switches SUL, SVL, SWL of all phases of the inverter 20 are turned off, thereby boosting the output voltage of the first storage battery 31 and supplying it to the low-voltage power supply target portion 230. In detail, the motor ECU 100 performs boost control, which is the above-mentioned switching control for controlling the power supply voltage VB to the target power supply voltage. As a result, power is supplied from the first storage battery 31 to the low-voltage power supply target portion 230.

[0111] In the external power supply control of this embodiment, similarly to the fourth embodiment, the motor ECU 100 generates a gate signal so that the current phase β has the value described in the first embodiment or the modified example of the first embodiment, and performs boost control of the inverter 20. This makes it possible to maintain the rotor 13 in a rotation stopped state during the external power supply control.

[0112] Next, the equalization control of this embodiment will be described. Fig. 18 shows the control state of each switch during the equalization control. Note that during the equalization control, each of the connection switches DCRH and DCRL is turned off.

[0113] The motor ECU 100 turns on the high potential side main switch SMRH, the low potential side main switch SMRL, the inter-battery switch 50, the first motor side switch 71, and the second motor side switch 72, and turns off the pre-charge main switch SMRP and the bypass switch 61. The motor ECU 100 also performs switching control for at least one phase of the inverter 20 to transfer power from one of the first storage battery 31 and the second storage battery 32 to the other.

[0114] Specifically, the motor ECU 100 performs a first control to supply current from the second storage battery 32 to the first storage battery 31 by performing a step-down control for at least one phase. Also, the motor ECU 100 performs a second control to supply current from the first storage battery 31 to the second storage battery 32 by performing a step-up control for at least one phase.

[0115] In the first or second equalization control of this embodiment, similarly to the fifth embodiment, the motor ECU 100 generates a gate signal so that the current phase β becomes the value described in the first embodiment or the modified example of the first embodiment, and performs step-down control or step-up control of the inverter 20. This makes it possible to maintain the rotor 13 in a rotation-stopped state during the equalization control.

[0116] <Other embodiments> Each of the above embodiments may be modified as follows.

[0117] In the first, second, and fourth to sixth embodiments, the motor ECU 100 may fix the number of phases of the switches used in the boost control, without changing the number of phases as in steps S11 to S15 in FIG.

[0118] The control of the second embodiment may be applied to the third to sixth embodiments.

[0119] The motor is not limited to one having reverse saliency, but may be one having forward saliency, which is a characteristic in which the d-axis inductance Ld is greater than the q-axis inductance Lq.

[0120] In each of the above embodiments, the power conversion device does not necessarily have to include either the first or second motor-side switch 71, 72. In addition, the power conversion device does not necessarily have to include both the first and second motor-side switches 71, 72.

[0121] The switches of the inverter 20 are not limited to IGBTs, and may be, for example, N-channel MOSFETs equipped with body diodes. In this case, the high potential side terminal of the N-channel MOSFET becomes the drain, and the low potential side terminal becomes the source.

[0122] The high potential side main switch SMRH does not have to be provided.

[0123] Instead of the low potential side main switch SMRL, a series connection of the pre-charge main switch SMRP and the pre-charge resistor 40 may be connected in parallel to the high potential side main switch SMRH. In this case, the low potential side main switch SMRL does not have to be provided.

[0124] The fuses 41 and 42 do not necessarily have to be provided.

[0125] The motor is not limited to a star-connected one, and may be a delta-connected one. The motor and inverter are not limited to a three-phase one, and may be a two-phase one, or a four-phase or more phase one. The motor is not limited to a permanent magnet-type synchronous machine having a permanent magnet as a field pole on the rotor, and may be a wound field-type synchronous machine having a field winding as a field pole on the rotor. In this case, the rotor may be provided with both a field winding and a permanent magnet. The motor is not limited to a synchronous machine, and may be an induction machine.

[0126] The control device that performs external charging, power supply control, and equalization control is not limited to the motor ECU 100. For example, each control may be performed by a plurality of control devices, such as the battery ECU 90, the EVECU 110, and the motor ECU 100, working together.

[0127] The power storage unit to be charged by the external charger is not limited to a storage battery. For example, it may be a large-capacity electric double-layer capacitor, or may be one that includes both a storage battery and an electric double-layer capacitor.

[0128] The moving body on which the power conversion device is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. The power conversion device is not limited to a moving body, but may be a stationary device.

[0129] The control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor and a memory programmed to execute one or more functions embodied in a computer program. Alternatively, the control device and the method described in the present disclosure may be realized by a special-purpose computer provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device and the method described in the present disclosure may be realized by one or more special-purpose computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions executed by the computer.

[0130] Characteristic configurations extracted from the above-described embodiments will be described below. [Configuration 1] An inverter (20) having upper and lower arm switches (SUH to SWL) of multiple phases; a motor (10) having an armature winding (11U to 11W) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a rotor (13); In a power conversion device comprising: a high potential side path (22H) electrically connecting a positive electrode terminal of the first power storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of the second power storage unit (32) and a low potential side terminal of the lower arm switch; an inter-storage unit switch (50) that, when turned on, electrically connects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit, and, when turned off, electrically disconnects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit; a bypass switch (60, 61) that electrically connects negative electrode terminals of the first power storage unit and the second power storage unit to each other and electrically connects positive electrode terminals of the first power storage unit and the second power storage unit to each other; a connection path (73) electrically connecting the negative terminal of the first storage unit or the positive terminal of the second storage unit to the armature winding; and a control device (100) that performs switching control of a target switch, which is at least one of the upper and lower arm switches, so as to pass a current through the connection path under the condition that the torque generated by the motor is a torque capable of maintaining a stopped state of the rotor. [Configuration 2] The power conversion device according to configuration 1, wherein the control device controls switching of the target switch so that an angle between a d-axis of a dq coordinate system and a current vector flowing through the armature winding is equal to or smaller than 45°. [Configuration 3] The power conversion device according to configuration 2, wherein the control device performs switching control of the target switch so that an angle between a d-axis of a dq coordinate system and the current vector is equal to or smaller than 35°. [Configuration 4] The power conversion device of configuration 3, wherein when the sign of the angle between the positive d-axis and the current vector is positive when the current vector rotates counterclockwise with the positive d-axis of a dq coordinate system as a reference, the control device performs switching control of the target switch so that the angle between the positive d-axis and the current vector is greater than or equal to -35° and less than or equal to +35°. [Configuration 5] The power conversion device according to configuration 3, wherein the control device performs switching control of the target switch so that an angle between the negative d-axis of a dq coordinate system and the current vector is smaller than an angle between the current vector and the negative d-axis in a case where minimum current maximum torque control is performed. [Configuration 6] 6. The power conversion device according to any one of configurations 2 to 5, wherein the control device performs switching control of the target switches so that the sign of the torque generated by the motor is alternately inverted. [Configuration 7] the inverter is a three-phase inverter, The control device includes: Select the number of phases of the target switch, The power conversion device according to any one of configurations 1 to 6, wherein when the selected number of phases is two, switching control is performed on the target switches corresponding to two of the three phases for which the magnitude of the d-axis current flowing through the armature winding is the smallest. [Configuration 8] the bypass switch (60) electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit when turned on, and electrically disconnects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit when turned off; The power conversion device according to any one of configurations 1 to 7, wherein the connection path electrically connects the armature winding and a positive terminal of the second power storage unit. [Configuration 9] The power conversion device according to configuration 8, wherein, when an external charger (210) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the upper arm switch, which is the target switch, in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external charging control to charge the second storage unit by causing a current to flow through a closed circuit including the external charger, the inverter, the armature winding, the connection path, and the second storage unit. [Configuration 10] The power conversion device according to configuration 8, wherein, when an external power supply target unit (230) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch, which is the target switch, in a state in which the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external power supply control to supply a current from the second power storage unit to the external power supply target unit via the connection path, the armature winding, and the inverter. [Configuration 11] the bypass switch (61) electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit when turned on, and electrically disconnects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit when turned off; The power conversion device according to any one of configurations 1 to 7, wherein the connection path electrically connects the armature winding and a negative electrode terminal of the first power storage unit. [Configuration 12] The power conversion device according to configuration 11, wherein, when an external charger (210) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch, which is the target switch, in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external charging control to charge the first storage unit by passing a current through a closed circuit including the external charger, the first storage unit, the connection path, the armature winding, and the inverter. [Configuration 13] The power conversion device according to configuration 11, wherein, when an external power supply target part (230) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch, which is the target switch, in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external power supply control to supply current to the external power supply target part via a closed circuit including the external power supply target part, the first power storage unit, the connection path, the armature winding, and the inverter. [Configuration 14] The control device includes: a first control for supplying a current from the first power storage unit to the second power storage unit via the inverter, the armature winding, and the connection path by performing switching control of the upper arm switch as the target switch in a state in which the inter-power storage unit switch is turned on and the bypass switch is turned off; a second control for supplying a current from the second power storage unit to the first power storage unit via the connection path, the armature winding, and the inverter by performing switching control of the lower arm switch as the target switch in a state in which the inter-power storage unit switch is turned on and the bypass switch is turned off; 12. The power conversion device according to configuration 8 or 11, [Explanation of symbols]

[0131] 10...motor, 11U, 11V, 11W...armature winding, 13...rotor, 20...inverter, 22H...high potential side path, 22L...low potential side path, 31, 32...first and second storage batteries, 50...inter-battery switch, 60...bypass switch, 73...connection path, 100...motor ECU.

Claims

1. An inverter (20) having upper and lower arm switches (SUH to SWL) for multiple phases; a motor (10) having an armature winding (11U to 11W) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a rotor (13); In a power conversion device comprising: a high potential side path (22H) electrically connecting a positive terminal of the first storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of the second storage unit (32) and a low potential side terminal of the lower arm switch; an inter-storage unit switch (50) that, when turned on, electrically connects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit, and, when turned off, electrically disconnects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit; a bypass switch (60, 61) that electrically connects negative electrode terminals of the first power storage unit and the second power storage unit to each other and electrically connects positive electrode terminals of the first power storage unit and the second power storage unit to each other; a connection path (73) electrically connecting the negative terminal of the first storage unit or the positive terminal of the second storage unit to the armature winding; a control device (100) that performs switching control of a target switch, which is at least one of the upper and lower arm switches, so as to flow current through the connection path under the condition that the torque generated by the motor is a torque capable of maintaining a stopped state of the rotor.

2. 2. The power conversion device according to claim 1, wherein the control device controls switching of the target switch so that an angle between a d-axis of a dq coordinate system and a current vector flowing through the armature winding is equal to or smaller than 45°.

3. The power conversion device according to claim 2 , wherein the control device performs switching control of the target switch such that an angle between a d axis of a dq coordinate system and the current vector is equal to or smaller than 35°.

4. 4. The power conversion device according to claim 3, wherein when the sign of the angle between the positive d-axis and the current vector when the current vector rotates counterclockwise with respect to the positive d-axis of a dq coordinate system, is positive, the control device controls the switching of the target switch so that the angle between the positive d-axis and the current vector is -35° or more and +35° or less.

5. 4. The power conversion device according to claim 3, wherein the control device performs switching control of the target switch so that an angle between a negative d-axis of a dq coordinate system and the current vector is smaller than an angle between the current vector and the negative d-axis when minimum current maximum torque control is performed.

6. The power conversion device according to claim 2 , wherein the control device performs switching control of the target switches so that a sign of the torque generated by the motor is alternately inverted.

7. the inverter is a three-phase inverter, The control device includes: Select the number of phases of the target switch, The power conversion device according to any one of claims 1 to 3, wherein when the selected number of phases is two, switching control is performed on the target switches corresponding to two phases among three phases in which a magnitude of a d-axis current flowing through the armature winding is smallest.

8. the bypass switch (60) electrically connects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit when turned on, and electrically disconnects the negative electrode terminal of the first power storage unit and the negative electrode terminal of the second power storage unit when turned off; The power conversion device according to claim 4 , wherein the connection path electrically connects the armature winding and a positive terminal of the second power storage unit.

9. 9. The power conversion device according to claim 8, wherein, when an external charger (210) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the upper arm switch which is the target switch in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external charging control to charge the second storage unit by causing a current to flow through a closed circuit including the external charger, the inverter, the armature winding, the connection path, and the second storage unit.

10. 9. The power conversion device according to claim 8, wherein, when an external power supply target unit (230) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch, which is the target switch, in a state in which the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external power supply control to supply a current from the second power storage unit to the external power supply target unit via the connection path, the armature winding, and the inverter.

11. the bypass switch (61) electrically connects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit when turned on, and electrically disconnects the positive electrode terminal of the first power storage unit and the positive electrode terminal of the second power storage unit when turned off; The power conversion device according to claim 4 , wherein the connection path electrically connects the armature winding and a negative electrode terminal of the first power storage unit.

12. 12. The power conversion device according to claim 11, wherein, when an external charger (210) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch which is the target switch in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external charging control to charge the first storage unit by causing a current to flow through a closed circuit including the external charger, the first storage unit, the connection path, the armature winding, and the inverter.

13. 12. The power conversion device according to claim 11, wherein, when an external power supply target part (230) is electrically connected to the high potential side path and the low potential side path, the control device performs switching control of the lower arm switch which is the target switch in a state where the inter-storage unit switch is turned off and the bypass switch is turned on, thereby performing external power supply control to supply a current to the external power supply target part via a closed circuit including the external power supply target part, the first power storage unit, the connection path, the armature winding, and the inverter.

14. The control device includes: a first control for supplying a current from the first power storage unit to the second power storage unit via the inverter, the armature winding, and the connection path by performing switching control of the upper arm switch as the target switch in a state in which the inter-power storage unit switch is turned on and the bypass switch is turned off; a second control for supplying a current from the second power storage unit to the first power storage unit via the connection path, the armature winding, and the inverter by performing switching control of the lower arm switch as the target switch in a state in which the inter-power storage unit switch is turned on and the bypass switch is turned off; The power conversion device according to claim 8 or 11, further comprising:

15. An inverter (20) having upper and lower arm switches (SUH to SWL) for multiple phases; a motor (10) having an armature winding (11U to 11W) electrically connected to a low potential side terminal of the upper arm switch of each phase and a high potential side terminal of the lower arm switch of each phase, and a rotor (13); A computer (101); A program applied to a power conversion device comprising: The power conversion device is a high potential side path (22H) electrically connecting a positive terminal of the first storage unit (31) and a high potential side terminal of the upper arm switch; a low potential side path (22L) electrically connecting a negative terminal of the second storage unit (32) and a low potential side terminal of the lower arm switch; an inter-storage unit switch (50) that, when turned on, electrically connects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit, and, when turned off, electrically disconnects the negative electrode terminal of the first storage unit and the positive electrode terminal of the second storage unit; a bypass switch (60, 61) that electrically connects negative electrode terminals of the first power storage unit and the second power storage unit to each other and electrically connects positive electrode terminals of the first power storage unit and the second power storage unit to each other; a connection path (73) electrically connecting the negative terminal of the first storage unit or the positive terminal of the second storage unit to the armature winding; Equipped with The computer includes: A program that executes a process of controlling switching of a target switch, which is at least one of the upper and lower arm switches, in order to flow current through the connection path under the condition that the torque generated by the motor is a torque that can maintain the rotor in a stopped state.

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