Power conversion device, program, and control method for power conversion device

Abstract

The power conversion device includes: an inverter (20) with multi-phase upper and lower arm switches (SUH~SWL); a motor (10) with armature windings (11U~11W); a high-potential side path (22H); a low-potential side path (22L); a connection path (73); and a control device (100). The control device includes: a switch control unit (145) for switching control of the upper and lower arm switches; and a threshold determination unit (144) for determining whether a determination parameter (α), which is the ratio of the neutral point voltage of the armature winding to the voltage difference between the high-potential side path and the low-potential side path, or a related value of the ratio, is below a threshold. If it is determined that the determination parameter is greater than the threshold, the switch control unit performs switch control with an additional condition that makes the determination parameter below the threshold.

Description

[0001] Cross-reference of related applications

[0002] This application is based on Japanese Application No. 2024-064152, filed on April 11, 2024, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a power conversion device, a program, and a control method for the power conversion device. Background Technology

[0004] Previously, a power conversion device for use in systems equipped with an energy storage unit was known. The power conversion device includes an inverter and a motor. As a control device for the power conversion device, there exists a device that drives the motor while performing temperature control of the energy storage unit. Furthermore, as such a power conversion device, there exists, for example, the device described in Patent Document 1.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2021-093845.

[0008] There are concerns about reduced efficiency in temperature control and potential adverse effects in the control of the aforementioned power conversion device. Summary of the Invention

[0009] The main objective of this disclosure is to provide a power conversion device, a program, and a control method for power conversion devices that can suppress malfunctions in the control of power conversion devices.

[0010] In this disclosure, the power conversion device includes:

[0011] An inverter having multi-phase upper arm switches and lower arm switches; and

[0012] The motor has an armature winding that is electrically connected to the low-potential side terminal of the upper arm switch of each phase and the high-potential side terminal of the lower arm switch of each phase.

[0013] Its characteristic is that it possesses:

[0014] A high-potential side path electrically connects the positive terminal of the first energy storage unit to the high-potential side terminal of the upper arm switch.

[0015] A low-potential side path electrically connects the negative terminal of the second energy storage unit to the low-potential side terminal of the lower arm switch.

[0016] A connection path electrically connects the negative terminal of the first energy storage unit or the positive terminal of the second energy storage unit to the armature winding; and

[0017] Control device,

[0018] The control device includes:

[0019] A temperature rise determination unit determines whether there is a temperature rise requirement that would cause an alternating heating current to flow between the first energy storage unit and the second energy storage unit via the armature winding and the connection path.

[0020] An action determination unit determines whether there is an action requirement that causes a DC operating current to flow through at least one of the first energy storage unit and the second energy storage unit.

[0021] The switch control unit, upon determining that both the heating requirement and the operation requirement exist, controls the switching of the upper arm switch and the lower arm switch, such that the heating current flows between the first and second energy storage units, and the operation current flows through at least one of the first and second energy storage units; and

[0022] A threshold determination unit determines whether a determination parameter is below a threshold value. This determination parameter is either the ratio of the neutral point voltage of the armature winding to the voltage difference between the high-potential side path and the low-potential side path, or a related value of the ratio.

[0023] If the determination parameter is determined to be greater than the threshold, the switch control unit performs a restriction control, which is a switch control that adds a condition to make the determination parameter fall below the threshold.

[0024] The power conversion device heats up the first and second energy storage units by passing an alternating heating current through the armature winding and the connection path between them. Sometimes, temperature control of the first and second energy storage units and operation control of causing a direct current to flow through at least one of the first and second energy storage units are performed.

[0025] When temperature control is implemented, a current for carrying the temperature-increasing current flows through the armature winding. When a current for carrying the temperature-increasing current flows through the armature winding and operation control is implemented, there is a concern that the effect obtained by controlling either the temperature control or the operation control may be smaller than intended.

[0026] Here, when it is determined that the aforementioned determination parameter is greater than the threshold, the switch control unit of this disclosure performs additional restriction control to make the determination parameter lower than the threshold. This allows the determination parameter to be maintained below the threshold, and temperature control and operation control to be performed. Therefore, even when temperature control and operation control are performed, it is possible to suppress the undesirable situation where the effect obtained by controlling either temperature control or operation control becomes smaller than intended. Attached Figure Description

[0027] The foregoing and other objects, features, and advantages of this disclosure will become more apparent from the following detailed description with reference to the accompanying drawings. The drawings are:

[0028] Figure 1 This is a diagram showing the overall structure of the system involved in the first embodiment.

[0029] Figure 2 This is a diagram showing the control state of the switch when the motor is driven.

[0030] Figure 3 This is a diagram showing the control state of the switch during high-voltage charging.

[0031] Figure 4 This is a diagram showing the control state of the switch during low-voltage charging.

[0032] Figure 5 This is a diagram showing the equivalent circuit.

[0033] Figure 6 This is a diagram showing the equivalent circuit.

[0034] Figure 7 This is a functional block diagram illustrating the processing of a microcomputer.

[0035] Figure 8 This is a diagram showing the waveform of the neutral point command current.

[0036] Figure 9 It is a timing diagram showing the shift of the modulation rate.

[0037] Figure 10 This is a functional block diagram illustrating the processing of a microcomputer.

[0038] Figure 11 This is a flowchart illustrating the steps of the temperature control process.

[0039] Figure 12 This is a diagram illustrating the overall structure of the system involved in the second embodiment.

[0040] Figure 13 This is a diagram showing the control state of the switch during low-voltage charging.

[0041] Figure 14 This is a diagram illustrating the overall structure of the system involved in other embodiments. Detailed Implementation

[0042] Referring to the accompanying drawings, several embodiments are described. In these embodiments, sometimes functionally and / or structurally corresponding and / or related parts are labeled with the same reference numerals, or with different reference numerals of more than one hundred digits. For details regarding corresponding and / or related parts, please refer to the descriptions of other embodiments.

[0043] <First Implementation Method>

[0044] Hereinafter, with reference to the accompanying drawings, a first embodiment of the power conversion device according to this disclosure will be described. The power conversion device of this embodiment is mounted in vehicles such as electric vehicles and hybrid vehicles, constituting an onboard system.

[0045] like Figure 1 As shown, 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 motor with star-connected armature windings 11 for phases U, V, and W and a rotor 13. The armature windings 11 of each phase are arranged with an electrical angle offset of 120°. The motor 10 is, for example, a permanent magnet synchronous motor. The rotor 13 is capable of transmitting power to the vehicle's drive wheels. Therefore, the motor 10 becomes the source of torque that propels the vehicle.

[0046] The inverter 20 has a series connection of three-phase upper and lower arm switches. Specifically, the inverter 20 has upper arm switches SUH, SVH, and SWH for phases U, V, and W, and lower arm switches SUL, SVL, and SWL for phases U, V, and W. Upper arm diodes DUH, DVH, and DWH for phases U, V, and W, acting as freewheeling diodes, are connected in anti-parallel to the upper arm switches SUH, SVH, and SWH. Lower arm diodes DUL, DVL, and DWL for phases U, V, and W, acting as freewheeling diodes, are connected in anti-parallel to the lower arm switches SUL, SVL, and SWL. In this embodiment, each switch SUH, SVH, SWH, SUL, SVL, and SWL is an IGBT.

[0047] The inverter 20 includes a smoothing capacitor 21. A long strip-shaped high-potential side path 22H is connected to the high-potential side terminal of the smoothing capacitor 21. A long strip-shaped low-potential side path 22L is connected to the 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 busbars. Alternatively, the smoothing capacitor 21 may be located outside the inverter 20.

[0048] At the connection point between the emitter of the low-potential side terminal of the upper arm switches SUH, SVH, and SWH of phases U, V, and W, and the collector of the high-potential side terminal of the lower arm switches SUL, SVL, and SWL of phases U, V, and W, the first terminals of the armature windings 11U, 11V, and 11W of phases U, V, and W are connected to each other at the neutral point O. Furthermore, in this embodiment, the number of turns of the armature windings 11U, 11V, and 11W of phases U, V, and W are set to be the same. Therefore, the inductance of the armature windings 11U, 11V, and 11W of phases U, V, and W is, for example, set to be the same.

[0049] The collectors of the upper arm switches SUH, SVH, and SWH in phases U, V, and W are connected to a high-potential path 22H. The emitters of the lower arm switches SUL, SVL, and SWL in phases U, V, and W are connected to a low-potential path 22L. In this embodiment, the voltage between the high-potential path 22H and the low-potential path 22L is referred to as the power supply voltage V. bat .

[0050] The system includes a first battery 31 (equivalent to a "first energy storage unit") and a second battery 32 (equivalent to a "second energy storage unit"). Each battery 31 and 32 is a power supply source for driving the rotor 13 of the motor 10 to rotate. Each battery 31 and 32 is a battery pack consisting of multiple unit batteries connected in series. A unit battery is a single battery cell or a series connection of multiple battery cells. In this embodiment, the full charge capacity (specifically, for example, the rated full charge capacity) [Ah] of each unit battery constituting the first battery 31 and the second battery 32 is the same. The positive terminal of the first battery 31 is connected to the high-potential side path 22H via a first fuse 41, and the negative terminal of the second battery 32 is connected to the low-potential side path 22L via a second fuse 42. The terminal voltages (e.g., rated voltages) of each battery cell constituting the battery pack are, for example, set to be the same for each other. The battery cells are, for example, secondary batteries such as lithium-ion batteries. In this embodiment, the inter-terminal voltage (e.g., rated voltage) of the first battery 31 is higher than the inter-terminal voltage (e.g., rated voltage) of the second battery 32. This configuration can be achieved, for example, by having more unit cells constituting the first battery 31 than the number of unit cells constituting the second battery 32.

[0051] The power conversion device includes a main switch for electrically connecting or disconnecting the first battery 31, the second battery 32, and the inverter 20. Specifically, the main switches include a high-potential side main switch SMRH, a low-potential side main switch SMRL, and a pre-charge main switch SMRP. In this embodiment, each main switch SMRH, SMRL, and SMRP is a mechanical relay. Each main switch SMRH, SMRL, and SMRP prevents bidirectional current flow when turned off and allows bidirectional current flow when turned on. The high-potential side main switch SMRH is located in the high-potential side path 22H, and the low-potential side main switch SMRL is located in the low-potential 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-potential side main switch SMRL. Furthermore, each main switch SMRH, SMRL, and SMRP is not limited to a mechanical relay; for example, it may be a semiconductor switching element.

[0052] Each battery 31 and 32 can be charged by an external charger located outside the vehicle via an external charging control. The external charger is, for example, a stationary charger.

[0053] 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 the external charger from the first battery 31 and the second battery 32. In this embodiment, each connection switch DCRH and DCRL is a mechanical relay. Each connection switch DCRH and DCRL prevents bidirectional current flow when it is turned off and allows bidirectional current flow when it is turned on. The high-potential side connection switch DCRH is located in the portion of the high-potential side path 22H closer to the inverter 20 side than the high-potential side main switch SMRH. The low-potential side connection switch DCRL is located in the portion of the low-potential side path 22L closer to the inverter 20 side than the low-potential side main switch SMRL. Furthermore, each connection switch DCRH and DCRL is not limited to a mechanical relay; for example, it may be a semiconductor switching element.

[0054] The power conversion device includes a battery-side switch 50, a bypass switch 60, a first motor-side switch 71, a second motor-side switch 72, and a connection path 73, configured to switch the connection state of the first battery 31 and the second battery 32. In this embodiment, the battery-side switch 50, the bypass switch 60, and each motor-side switch 71, 72 are mechanical relays. When the battery-side switch 50, the bypass switch 60, and each motor-side switch 71, 72 are turned off, they prevent the flow of bidirectional current; when they are turned on, they allow the flow of bidirectional current. Furthermore, the battery-side switch 50, the bypass switch 60, and each motor-side switch 71, 72 are not limited to mechanical relays; for example, they may also be semiconductor switching elements.

[0055] The battery compartment switch 50 connects the negative terminal of the first battery 31 to the positive terminal of the second battery 32. When the battery compartment switch 50 is turned on, the negative terminal of the first battery 31 and the positive terminal of the second battery 32 are electrically connected. Conversely, when the battery compartment switch 50 is turned off, the negative terminal of the first battery 31 and the positive terminal of the second battery 32 are electrically disconnected.

[0056] The bypass switch 60 connects the negative terminal of the first battery 31 to the low-potential side path 22L. By turning on the bypass switch 60, the negative terminal of the first battery 31 and the negative terminal of the second battery 32 are electrically connected. On the other hand, by turning off the bypass switch 60, the negative terminal of the first battery 31 and the negative terminal of the second battery 32 are electrically disconnected.

[0057] Furthermore, in this embodiment, the first battery 31 and the second battery 32 constitute the battery unit 30.

[0058] Connection path 73 is an electrical path connecting the low-potential side intermediate terminal BL to the neutral point O. The low-potential side intermediate terminal BL is located on the path connecting the battery compartment switch 50 and the positive terminal of the second battery 32. On connection path 73, starting from the second battery 32, a first motor side switch 71 and a second motor side switch 72 are sequentially arranged.

[0059] The power conversion device includes a neutral point capacitor 74, which serves as a capacitor connecting the connection path 73 and the low-potential side path 22L. A first end of the neutral point capacitor 74 is connected to the portion in 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 the portion in the low-potential side path 22L closer to the inverter 20 side compared to the low-potential side main switch SMRL and the pre-charge main switch SMRP.

[0060] By turning on the first motor-side switch 71, the first terminal of the neutral point capacitor 74 is electrically connected to the positive terminal of the second battery 32. Conversely, by turning off the first motor-side switch 71, the first terminal of the neutral point capacitor 74 is electrically disconnected from the positive terminal of the second battery 32. By turning on the second motor-side switch 72, the neutral point O of the armature winding 11 is electrically connected to the first terminal of the neutral point capacitor 74. Conversely, by turning off the second motor-side switch 72, the neutral point O is electrically disconnected from the first terminal of the neutral point capacitor 74.

[0061] 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, serving as current sensors to detect the current flowing through its various parts. The first current sensor 81A detects the current flowing through the first battery 31, and the second current sensor 81B detects the current flowing through the second battery 32. The phase current sensor 82 detects the current flowing through the U, V, and W phase armature windings 11U, 11V, and 11W, respectively. The motor current sensor 83 detects the current flowing through the connection path 73; in this embodiment, it detects the current flowing through the portion of the connection path 73 closer to the neutral point O than the connection point with the neutral point capacitor 74.

[0062] The power conversion device includes a capacitor voltage sensor 84 for detecting the inter-terminal voltage of the neutral point capacitor 74, a first voltage sensor 85A for detecting the inter-terminal voltage of the first battery 31, and a second voltage sensor 85B for detecting the inter-terminal voltage of the second battery 32. Additionally, the power conversion device includes a power supply voltage sensor 86 for detecting the inter-terminal voltage of the smoothing capacitor 21 (hereinafter referred to as the smoothing capacitor voltage Vdc) and a rotation angle sensor 87 for detecting the rotation angle (electrical angle) of the rotor 13. The power conversion device also includes a first temperature sensor 88A for detecting the temperature of the first battery 31 and a second temperature sensor 88B for detecting the temperature of the second battery 32.

[0063] 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 coordinates the entire system. The battery ECU 90 is an electronic control unit (ECU) with a processor 91 and a storage unit 92. The motor ECU 100 is an electronic control unit with a processor 101 and a storage unit 102. The EVECU 110 is an electronic control unit with a processor 111 and a storage unit 112. Furthermore, the EVECU 110 is a higher-level control unit than both the battery ECU 90 and the motor ECU 100. The battery ECU 90 and the motor ECU 100 can exchange information via the EVECU 110.

[0064] Storage units 92, 102, and 112 include memory and storage devices as hardware. The memory is a storage device used to store data used in the processing of the battery ECU 90, motor ECU 100, or EVECU 110. For example, the memory provides a working area to the processors 91, 101, and 111 for temporary use during processing. The memory may include, for example, ROM or RAM. The storage device is a storage device that stores various programs and data read and executed by the processors 91, 101, and 111; it is a non-transitory tangible storage medium. The storage device may include, for example, HDD or flash memory. The storage device stores data used for purposes described later. Figure 11 Information such as processing procedures.

[0065] Furthermore, for example, storage units 92, 102, and 112 may contain program information stored on a non-transitory physical storage medium. This storage medium may be, for example, a USB flash drive, CD-ROM, or DVD. Additionally, storage units 92, 102, and 112 may contain program information transmitted via a communication network, such as OTA (Over-The-Air) communication.

[0066] The detection values ​​of the first current sensor 81A, the second current sensor 81B, the first voltage sensor 85A, the second voltage sensor 85B, and the first temperature sensor 88A and the second temperature sensor 88B are input to the battery ECU 90. The detection values ​​of the phase current sensor 82, the motor current sensor 83, the capacitor voltage sensor 84, the power supply voltage sensor 86, and the rotation angle sensor 87 are input to the motor ECU 100.

[0067] Furthermore, each main switch SMRH, SMRL, SMRP, battery compartment switch 50, bypass switch 60, and each motor-side switch 71, 72 can be controlled by any one of the battery ECU 90, motor ECU 100, or EVECU 110, or by an ECU other than ECUs 90, 100, and 110. In this embodiment, it is assumed that each main switch SMRH, SMRL, SMRP, battery compartment switch 50, bypass switch 60, and each motor-side switch 71, 72 are controlled by motor ECU 100.

[0068] Next, the drive control will be explained. Through drive control, the rotor 13 of the drive motor 10 rotates.

[0069] Figure 2The control states of each switch are shown when drive control is executed. When the motor ECU 100 determines that a drive requirement (equivalent to an "action requirement") exists, it shuts off the connection switches DCRH, DCRL, bypass switch 60, pre-charge main switch SMRP, first motor-side switch 71, and second motor-side switch 72, and turns on the high-potential side main switch SMRH, low-potential side main switch SMRL, and battery-side switch 50. In this embodiment, the drive requirement is the requirement to drive the vehicle to move by rotating the rotor 13.

[0070] In drive control, the motor ECU 100 controls the switching of the upper and lower arm switches SUH to SWL of each phase of the inverter 20 based on the detection values ​​of each sensor, thereby feeding back the control quantity of the motor 10 as a command value. The control quantity 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 is transmitted to the drive wheels, thus propelling the vehicle.

[0071] Next, the external charging control will be explained.

[0072] In this embodiment, such as Figure 3 and Figure 4 As shown, the external charger is either a high-voltage charger 200 or a low-voltage charger 210. The charging voltage of the high-voltage charger 200 is a voltage higher than the terminal voltage (specifically, the rated voltage) of the series connection of the first battery 31 and the second battery 32, for example, 800V. The charging voltage of the low-voltage charger 210 is a voltage lower than the terminal voltage (specifically, the rated voltage) of the series connection of the first battery 31 and the second battery 32, but higher than the terminal voltage (specifically, the rated voltage) of the first battery 31, for example, 400V. When the first battery 31 and the second battery 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 based on 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.

[0073] Figure 3The control states of each switch are shown when using external charging control with the high-voltage charger 200. The motor ECU 100 determines, for example, that a high-voltage charging requirement exists (equivalent to an "operational requirement") and executes external charging control using the high-voltage charger 200. The charging plug of the high-voltage charger 200 is electrically connected to the connection switches DCRH and DCRL by the vehicle user, thereby electrically connecting the high-voltage charger 200 to the power conversion device. The motor ECU 100 determines that a high-voltage charging requirement exists when it determines that the external charger connected to the power conversion device is the high-voltage charger 200. When a high-voltage charging requirement is determined, the motor ECU 100 turns off the pre-charge main switch SMRP, bypass switch 60, first motor side switch 71, 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 battery compartment switch 50.

[0074] Thus, the first battery 31 and the second battery 32 are connected in series relative to the high-voltage charger 200. Therefore, current flows through a closed loop including the high-voltage charger 200, the high-potential side path 22H, the first battery 31, the battery-to-battery switch 50, the second battery 32, and the low-potential side path 22L, thereby charging the first battery 31 and the second battery 32 in a series connection. In this case, since the upper arm switches SUH, SVH, SWH of the inverter 20 and the second motor-side switch 72 are turned off, the charging current from the high-voltage charger 200 is prevented from flowing to the inverter 20 and the armature winding 11.

[0075] Figure 4 The control states of each switch are shown when using the external charging control of the low-voltage charger 210. The motor ECU 100 determines, for example, that a low-voltage charging requirement exists (equivalent to an "operational requirement") and executes external charging control using the low-voltage charger 210. The charging plug of the low-voltage charger 210 is electrically connected by the vehicle user to each of the connection switches DCRH and DCRL, thereby electrically connecting the low-voltage charger 210 to the power conversion device. The motor ECU 100 determines that a low-voltage charging requirement exists when it determines that the external charger connected to the power conversion device is the low-voltage charger 210. When the motor ECU determines that a low-voltage charging requirement exists, it turns off the pre-charge main switch SMRP and the battery-to-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, current flows through a closed loop including the low-voltage charger 210, the high-potential side path 22H, the first battery 31, the bypass switch 60, and the low-potential side path 22L, thereby charging the first battery 31.

[0076] In the external charging control based on the low-voltage charger 210, the motor ECU 100 performs switching control that alternately turns on the upper and lower arm switches of at least one phase, or performs switching control of the upper arm switch of at least one phase while all the lower arm switches SUL, SVL, and SWL of the inverter 20 are off, thereby reducing the output voltage of the low-voltage charger 210 and supplying it to the second battery 32. Specifically, the motor ECU 100 performs step-down control, which is the aforementioned switching control used to control the voltage detected by the capacitor voltage sensor 84 (hereinafter referred to as the neutral point capacitor voltage VN) to the target charging voltage Vtgt. As a result, current flows through a closed loop 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 battery 32, and the low-potential side path 22L, thereby charging the second battery 32. Because the terminal voltage of the second battery 32 is lower than that of the first battery 31, the target charging voltage of the second battery 32 is lower than that of the first battery 31. For convenience, in the external charging control based on the low-voltage charger 210, the upper and lower arm switches of at least one phase that alternately connects the motor ECU 100, and the upper arm switch of at least one phase that is controlled to switch when all phases of the inverter 20's lower arm switches SUL, SVL, and SWL are off, will be referred to as "object switches".

[0077] In this embodiment, the motor ECU 100 executes a heating / drive mode or a heating / charging mode. The heating / drive mode executes heating control and drive control, while the heating / charging mode executes heating control and external charging control. When the motor ECU 100 executes the heating / drive mode, Figure 2 In the middle, the first motor-side switch 71 and the second motor-side switch 72 are turned on. When the motor ECU 100 is in heating / charging mode, Figure 3 In the middle, turn on the first motor side switch 71 and the second motor side switch 72, or in Figure 4 In the middle, turn on the battery compartment switch 50.

[0078] In the temperature control, an alternating current is passed between the first battery 31 and the second battery 32 to raise their temperature. The temperature control will be explained below.

[0079] Figure 5 The equivalent circuit of the power conversion device used in the temperature control is shown. Figure 5In this diagram, each phase armature winding 11U to 11W is represented as armature winding 11, each upper arm switch SUH, SVH, and SWH is represented as upper arm switch SH, and each upper arm diode DUH, DVH, and DWH is represented as upper arm diode DH. Additionally, each lower arm switch SUL, SVL, and SWL is represented as lower arm switch SL, and each lower arm diode DUL, DVL, and DWL is represented as lower arm diode DL.

[0080] Figure 5 The equivalent circuit can be shown as Figure 6 The equivalent circuit. Figure 6 The circuit is a buck-boost chopper circuit capable of bidirectional power transfer between the first battery 31 and the second battery 32. Figure 6 In this diagram, IBH represents the current flowing through the first battery 31, VBH represents the inter-terminal voltage of the first battery 31, IBL represents the current flowing through the second battery 32, and VBL represents the inter-terminal voltage of the second battery 32. When charging current flows through the first battery 31 and the second battery 32, IBH and IBL become negative; when discharging current flows through the first battery 31 and the second battery 32, IBH and IBL become positive. Additionally, VR represents the inter-terminal voltage of the armature winding 11, and IMr represents the current flowing through the neutral point O. The neutral point current IMr flowing from the armature winding 11 through the connection path 73 towards the low-potential side intermediate terminal BL is considered positive, and the neutral point current IMr flowing from the low-potential side intermediate terminal BL through the connection path 73 towards the armature winding 11 is considered negative.

[0081] Reference Figure 6 When the upper arm switch SH is turned on, the inter-terminal voltage VR of the armature winding 11 becomes "VBH". On the other hand, when the lower arm switch SL is turned on, the inter-terminal voltage VR of the armature winding 11 becomes "-VBL". That is, by turning on the upper arm switch SH, the magnetizing current can flow in the armature winding 11 in the positive direction of the neutral point current IMr, and by turning on the lower arm switch SL, the magnetizing current can flow in the armature winding 11 in the negative direction of the neutral point current IMr.

[0082] Figure 7 A block diagram of the control performed in heating / driving mode is shown.

[0083] In the motor ECU 100, the d-axis and q-axis command current setting unit 120 sets the d-axis command current Id* and the q-axis command current Iq* based on the torque command value Trq* of the motor 10, and inputs them to the d-axis deviation calculation unit 121d and the q-axis deviation calculation unit 121q. The d-axis deviation calculation unit 121d calculates the d-axis current deviation ΔId by subtracting the d-axis current Idr from the d-axis command current Id*, and inputs it to the d-axis control unit 122d. The q-axis deviation calculation unit 121q calculates the q-axis current deviation ΔIq by subtracting the q-axis current Iqr from the q-axis command current Iq*, and inputs it to the q-axis control unit 122q. Here, the d-axis current Idr and the q-axis current Iqr are calculated based on the detection value of the phase current sensor 82 and the electrical angle of the motor 10. Furthermore, the electrical angle can be the detection value of the rotation angle sensor 87, or it can be an estimated value estimated by sensorless control.

[0084] The d-axis control unit 122d calculates the d-axis voltage Vd as an operating quantity for feedback control of the d-axis current deviation ΔId calculated by the d-axis deviation calculation unit 121d to 0, and inputs it to the three-phase conversion unit 123. The q-axis control unit 122q calculates the q-axis voltage Vq as an operating quantity for feedback control of the q-axis current deviation ΔIq calculated by the q-axis deviation calculation unit 121q to 0, and inputs it to the three-phase conversion unit 123. In this embodiment, proportional-integral control is used as the feedback control for each control unit 122d and 122q. However, the feedback control is not limited to proportional-integral control; for example, proportional-integral-derivative control could also be used.

[0085] The three-phase conversion unit 123 calculates the U-W phase command voltages Vu-Vw in the three-phase fixed coordinate system based on the d-axis voltage Vd, the q-axis voltage Vq, and the aforementioned electrical angles. The U-W phase command voltages Vu-Vw, when it is determined that there is a drive requirement, are sinusoidal signals with the same amplitude and each offset by 120 degrees in electrical angle.

[0086] The motor ECU 100 includes a temperature control unit 130. The temperature control unit 130 includes a command value setting unit 131, a neutral point deviation calculation unit 132, a neutral point control unit 133, and a U-W phase superposition unit 134U-134W.

[0087] The command value setting unit 131 sets the neutral point command current IM* and inputs it to the neutral point deviation calculation unit 132. In this embodiment, the waveform of the neutral point command current IM* is as follows: Figure 8The waveform shown is set as a sine wave. Specifically, the amplitude of the neutral point command current IM* is Ia, and the period is Tc. Furthermore, the neutral point command current IM* is set in a point-symmetric manner, relative to the moment when the value of the neutral point command current IM* changes from a value other than 0 to 0 (hereinafter referred to as the zero-crossing moment), so that the positive and negative neutral point command currents IM* are point-symmetrical. Therefore, in Figure 8 In this case, the period of the neutral point command current IM* from the first zero-crossing time C1 to the second zero-crossing time C2 is equal to the period from the second zero-crossing time C2 to the third zero-crossing time C3.

[0088] Furthermore, within one period Tc of the neutral point command current IM*, the areas S1 and S2 of the first region are equal. The area S1 of the first region is the region enclosed by the time axis of the neutral point command current IM* from the first zero-crossing time C1 to the second zero-crossing time C2 and the positive neutral point command current IM* within one period Tc. The area S2 of the second region is the region enclosed by the time axis of the neutral point command current IM* from the second zero-crossing time C2 to the third zero-crossing time C3 and the negative neutral point command current IM* within one period Tc.

[0089] By setting the area of ​​the first region S1 and the area of ​​the second region S2 to be equal, the charging and discharging current of the first battery 31 and the second battery 32 in one cycle Tc can be made consistent. Therefore, with temperature control, the difference between the terminal voltage VBH of the first battery 31 and the terminal voltage VBL of the second battery 32 can be suppressed from increasing.

[0090] return Figure 7 As explained, the neutral point deviation calculation unit 132 calculates the neutral point current deviation ΔIM by subtracting the neutral point current IMr, which is the current detected by the motor current sensor 83, from the neutral point command current IM*, and inputs it to the neutral point control unit 133.

[0091] The neutral point control unit 133 calculates the offset correction amount CF as an operating quantity for feedback control of the calculated neutral point current deviation ΔIM to 0, and inputs it to the U-W phase superposition unit 134U-134W. In this embodiment, proportional-integral control is used as the feedback control. However, the feedback control is not limited to proportional-integral control; for example, proportional-integral-derivative control may also be used.

[0092] The U-phase superposition unit 134U calculates the final U-phase command voltage "Vu+CF" by adding an offset correction amount CF to the U-phase command voltage Vu input from the three-phase conversion unit 123. The V-phase superposition unit 134V calculates the final V-phase command voltage "Vv+CF" by adding an offset correction amount CF to the V-phase command voltage Vv input from the three-phase conversion unit 123. The W-phase superposition unit 134W calculates the final W-phase command voltage "Vw+CF" by adding an offset correction amount CF to the W-phase command voltage Vw input from the three-phase conversion unit 123.

[0093] The motor ECU 100 includes U-phase to W-phase modulation units 135U to 135W. The U-phase modulation unit 135U calculates the U-phase modulation rate Mu by dividing the final U-phase command voltage input from the U-phase superposition unit 134U by the smoothing capacitor voltage Vdc. The V-phase modulation unit 135V calculates the V-phase modulation rate Mv by dividing the final V-phase command voltage input from the V-phase superposition unit 134V by the smoothing capacitor voltage Vdc. The W-phase modulation unit 135W calculates the W-phase modulation rate Mw by dividing the final W-phase command voltage input from the W-phase superposition unit 134W by the smoothing capacitor voltage Vdc.

[0094] The motor ECU 100 controls the switching of each switch SUH to SWL based on the calculated modulation rates Mu, Mv, and Mw. Specifically, for example, the motor ECU 100 can control the switching by using PWM control based on the comparison between the modulation rates Mu, Mv, and Mw and the magnitude of the carrier signal (e.g., a triangular wave signal).

[0095] Figure 9 The shifts of each modulation rate Mu, Mv, and Mw are shown when the neutral point command current IM* is set to a sine wave. In this embodiment, the frequency of the neutral point command current IM* is lower than the frequencies of each modulation rate Mu, Mv, and Mw.

[0096] When the motor ECU 100 determines that there is a need for both heating and high-voltage charging, it executes a heating / charging mode. In this case, the motor ECU 100, for example... Figure 10 In the processing shown, the command voltages Vu, Vv, and Vw of phases U to W are taken as 0, and the modulation rates Mu, Mv, and Mw are calculated. The motor ECU 100 controls the switching of each switch SUH to SWL based on the calculated modulation rates Mu, Mv, and Mw. In this case, a current corresponding to the neutral point command current IM* flows through the armature windings 11U, 11V, and 11W of phases U to W.

[0097] When the motor ECU100 determines that there is a need for both heating and low-voltage charging, it executes a heating / charging mode. In this case, the heating / charging mode controls the neutral point current IMr to... Figure 8 The neutral point command current IM* is shown, and a step-down control mode is performed when using external charging control with low-voltage charger 210. By executing this mode by motor ECU 100, currents corresponding to the neutral point command current IM* and the step-down control flow in the U-W phase armature windings 11U, 11V, and 11W.

[0098] Figure 10 A block diagram of the control processing of the power conversion device executed by the motor ECU100 is shown.

[0099] The motor ECU 100 includes a temperature rise determination unit 140, an operation determination unit 141, a priority determination unit 142, and a switch control unit 145.

[0100] The temperature rise determination unit 140 determines whether there is a temperature rise requirement for the first battery 31 and the second battery 32. In this embodiment, the temperature rise determination unit 140 determines that a temperature rise requirement exists if it determines that the target temperature Tr is below the target temperature T*. Here, the target temperature Tr is, for example, the lower of the temperatures of the first battery 31 and the second battery 32, or the average temperature of the first battery 31 and the second battery 32. The temperature of the first battery 31 used in the temperature rise determination unit 140 is, for example, the detection value of the first temperature sensor 88A. The temperature of the second battery 32 used in the temperature rise determination unit 140 is, for example, the detection value of the second temperature sensor 88B. The temperature rise determination unit 140 inputs the determination result to the priority determination unit 142 and the switch control unit 145.

[0101] The rotation drive requirement of rotor 13 or the external charging requirement of the first battery 31 and the second battery 32 is input to the action determination unit 141. The action determination unit 141 determines whether the drive requirement or the external charging requirement has been input, and inputs the determination result to the priority determination unit 142 and the switch control unit 145.

[0102] When the input includes a determination result based on a temperature rise request issued by the temperature rise determination unit 140 and a determination result based on a drive request issued by the operation determination unit 141, the priority determination unit 142 determines which of the two requests—a temperature rise request or a drive request—should be prioritized. Similarly, when the input includes a determination result based on a temperature rise request issued by the temperature rise determination unit 140 and a determination result based on an external charging request issued by the operation determination unit 141, the priority determination unit 142 determines which of the two requests—a temperature rise request or an external charging request—should be prioritized. The priority determination unit 142 then inputs the determination result to the switch control unit 145.

[0103] If the determination results of the issued heating and driving requirements are input, for example, if the priority determination unit 142 determines that the heating target temperature Tr is below the heating priority temperature Th*, which is a temperature lower than the target temperature T*, it determines that the heating requirement is a priority heating requirement.

[0104] When inputting the results of both a heating request and an external charging request, for example, the priority determination unit 142 determines, based on the determination result of the EVECU 110, whether to prioritize the heating request or the external charging request. The EVECU 110, for example, obtains the target temperature Tr from the battery ECU 90 and calculates the output power W of the high-voltage charger 200 or the low-voltage charger 210. Based on the target temperature Tr and the output power W, the EVECU 110 calculates the first charging efficiency ηh of the first battery 31 and the second battery 32 when the heating request is prioritized, and the second charging efficiency ηc of the first battery 31 and the second battery 32 when the external charging request is prioritized. The EVECU 110 determines whether to prioritize the heating request or the external charging request by comparing the first charging efficiency ηh and the second charging efficiency ηc. Specifically, if the EVECU 110 determines that the first charging efficiency ηh is greater than the second charging efficiency ηc, it prioritizes the heating request. On the other hand, if the EVECU 110 determines that the first charging efficiency ηh is less than or equal to the second charging efficiency ηc, it prioritizes the external charging request. The EVECU110 inputs the determination result to the motor ECU100. Based on the determination result input from the EVECU110, the priority determination unit 142 determines whether to prioritize the heating requirement or the external charging requirement.

[0105] Additionally, for example, if the priority determination unit 142 determines that a priority heating requirement is needed when the temperature Tr of the target temperature is below zero degrees Celsius, the priority determination unit 142 may be a temperature above -20°C and below -10°C.

[0106] The motor ECU 100 includes a parameter calculation unit 143 and a threshold determination unit 144. The parameter calculation unit 143 calculates the energization rate α (equivalent to a "determination parameter"). The energization rate α is expressed by the following formula (eq1).

[0107] [Mathematical Expression 1]

[0108]

[0109] In the above equation (eq1), VO is the voltage at the neutral point O, called the neutral point voltage. Additionally, V... bat This is the power supply voltage.

[0110] [Heating / Drive Mode]

[0111] The neutral point voltage VO in the heating / driving mode is represented by the following equation (eq2).

[0112] [Mathematical Expression 2]

[0113]

[0114] In the above equation (eq2), R mg The impedance of each phase armature winding 11U to 11W is called the winding impedance. Additionally, IM... c The current flowing through each phase armature winding 11U to 11W is called the winding current. VL is the inter-terminal voltage of the second battery 32.

[0115] From the above equations (eq1) and (eq2), we can derive the following equation (eq3).

[0116] [Mathematical Expression 3]

[0117]

[0118] The parameter calculation unit 143 calculates the current carrying rate α based on the above formula (eq3). The parameter calculation unit 143 uses the amplitude Ia of the neutral point command current IM* or the phase current detected by the phase current sensor 82 (specifically, for example, the maximum value of the phase current) as the winding current IM. c That's it. Additionally, the parameter calculation unit 143 uses the sum of the detection values ​​from the first voltage sensor 85A and the second voltage sensor 85B as V. bat The value detected by the second voltage sensor 85B can be used as VL. Furthermore, as V... bat Alternatively, the smoothing capacitor voltage Vdc can be used.

[0119] [Heating / Charging Mode]

[0120] The neutral point voltage VO in the heating / charging mode is represented by the following equation (eq4).

[0121] [Mathematical Expression 4]

[0122]

[0123] In the above equation (eq4), R bat The impedance of the second battery 32.

[0124] From the above equations (eq1) and (eq4), we can derive the following equation (eq5).

[0125] [Mathematical Expression 5]

[0126]

[0127] Based on the above equation (eq5), the parameter calculation unit 143 calculates the current-carrying rate α of the heating / charging mode during low-voltage charging. The parameter calculation unit 143 uses the amplitude Ia of the neutral point command current IM* or the phase current detected by the phase current sensor 82 (specifically, for example, the maximum value of the phase current) as the winding current IM. c That's it. Additionally, the parameter calculation unit 143 uses the sum of the detection values ​​from the first voltage sensor 85A and the second voltage sensor 85B as V. bat The value detected by the second voltage sensor 85B can be used as VL. Furthermore, as V... bat Alternatively, the smoothing capacitor voltage Vdc can be used.

[0128] The parameter calculation unit 143 inputs the calculated energization rate α to the threshold determination unit 144. If the threshold determination unit 144 determines that the energization rate α is below the threshold, it inputs a determination result indicating that no restriction control will be performed to the switch control unit 145. Conversely, if the threshold determination unit 144 determines that the energization rate α is above the threshold, it inputs a determination result indicating that restriction control will be performed to the switch control unit 145. In this embodiment, the threshold is set to 1.

[0129] The determination results output from the temperature rise determination unit 140, the action determination unit 141, the priority determination unit 142, and the threshold determination unit 144 are input to the switch control unit 145. Based on the determination results, the switch control unit 145 inputs the switching signals of each upper and lower arm switch SUH~SWL to each upper and lower arm switch SUH~SWL. Specifically, the determination results based on the temperature rise determination unit 140 indicating that a temperature rise request has been issued, and the determination results based on the action determination unit 141 indicating that a drive request has been issued, are input to the switch control unit 145. In this case, the switch control unit 145 performs switching control on each upper and lower arm switch SUH~SWL to execute the temperature rise / drive mode.

[0130] Additionally, the determination results of the heating determination unit 140 (which has issued a heating request) and the determination results of the action determination unit 141 (which has issued an external charging request) are input to the switch control unit 145. In this case, the switch control unit 145 controls the switching of each upper and lower arm switch SUH to SWL to execute the heating / charging mode.

[0131] When the threshold determination unit 144 determines the execution limit control and the heating / drive mode is executed, the switch control unit 145 controls the switching of each upper and lower arm switch SUH to SWL such that the energization rate α is less than or equal to 1. Specifically, compared to the case where no limit control is executed, the switch control unit 145 sets the amplitude Ia of the neutral point command current IM* or the magnitude of the current vector flowing through the armature winding 11 to be smaller, and controls the switching of each upper and lower arm switch SUH to SWL.

[0132] When the threshold determination unit 144 inputs the determination result of the execution restriction control and the heating / charging mode is executed, the switch control unit 145 performs switching control on each upper and lower arm switch SUH to SWL in a manner that the energization rate α is less than 1. Specifically, compared with the case where no restriction control is executed, the switch control unit 145 sets the charging power of the second battery 32 during amplitude Ia or low-voltage charging to a smaller value and performs switching control on each upper and lower arm switch SUH to SWL. Reducing the charging power can be achieved, for example, by lowering the target charging voltage Vtgt of the second battery 32.

[0133] Figure 11 This is a flowchart illustrating the steps of the temperature control process. This process is repeated, for example, by the motor ECU 100 at a predetermined control cycle.

[0134] In step S10, the temperature rise determination unit 140 determines whether there is a temperature rise requirement for the first battery 31 and the second battery 32. If it is determined in step S10 that there is a temperature rise requirement, the process proceeds to step S11. In step S11, the switch control unit 145 calculates the neutral point command current IM*, which is the command value of the neutral point current IMr (equivalent to "temperature rise current") required to change the temperature of the target temperature Tr to the target temperature T*.

[0135] In step S12, the action determination unit 141 determines whether there is a rotation drive requirement for the rotor 13. If it is determined in step S12 that there is a drive requirement, the process proceeds to step S13, where the d-axis command current Id* and the q-axis command current Iq* are calculated in the d-axis and q-axis command current setting unit 120.

[0136] In step S14, the conduction rate α is calculated based on the amplitude Ia of the neutral point command current IM* calculated in step S11, the detection values ​​of the first voltage sensor 85A and the second voltage sensor 85B, and the above mathematical formula (eq3).

[0137] In step S15, the threshold determination unit 144 determines whether the current-carrying rate α calculated in step S15 is 1 or less. If it is determined in step S15 that the current-carrying rate α is 1 or less, the process proceeds to step S16.

[0138] In step S16, the heating / driving mode is executed in the switch control unit 145.

[0139] If it is determined in step S15 that the energization rate α is greater than 1, proceed to step S17. In step S17, the priority determination unit 142 determines whether to prioritize the heating requirement or the driving requirement.

[0140] If a priority for temperature increase is determined in step S17, the process proceeds to step S18, where a condition is added to reduce the energization rate α to 1 or less, decreasing at least one of the d-axis command current Id* and the q-axis command current Iq*. As a result, the final command voltages Vu+CF, Vv+CF, and Vw+CF for phases U to W decrease. Consequently, the maximum value of the current flowing through the armature windings 11U, 11V, and 11W in phases U to W decreases, thereby reducing the energization rate α.

[0141] On the other hand, if a priority drive requirement is determined, the process proceeds to step S19, where a condition is added to make the energization rate α less than 1, and the neutral point command current IM* is calculated by reducing the amplitude Ia. By reducing the amplitude Ia, the offset correction amount CF decreases, and the final command voltages Vu+CF, Vv+CF, and Vw+CF of phases U to W decrease. Therefore, the maximum value of the current flowing through the armature windings 11U, 11V, and 11W of phases U to W decreases, thereby reducing the energization rate α.

[0142] If it is determined in step S12 that there is no driving requirement, proceed to step S20 to determine whether there is an external charging requirement. Hereinafter, it is assumed that the external charging requirement is a low-voltage charging requirement.

[0143] If an external charging requirement is determined in step S20, the process proceeds to step S21. In step S21, the switching control unit 145 calculates the pass rate α based on the amplitude Ia calculated in step S11, the detection values ​​of the first voltage sensor 85A and the second voltage sensor 85B, and the aforementioned mathematical formula (eq5).

[0144] In step S22, the threshold determination unit 144 determines whether the current-carrying rate α is 1 or less. If it is determined in step S22 that the current-carrying rate α is 1 or less, the process proceeds to step S23.

[0145] In step S23, the heating / charging mode is executed in the switch control unit 145.

[0146] If it is determined in step S22 that the power-on rate α is greater than 1, proceed to step S24. In step S24, the priority determination unit 142 determines whether to prioritize the heating requirement or the external charging requirement.

[0147] If a priority for heating is determined in step S24, the process proceeds to step S25, where a condition is added to reduce the charging power of the second battery 32 to below 1. Specifically, this is done by reducing the target charging voltage Vtgt of the second battery 32. This reduces the charging power α.

[0148] On the other hand, if it is determined that the external charging requirement is prioritized, proceed to step S26, and add the condition that the energization rate α is less than 1, and calculate the neutral point command current IM* in a way that reduces the amplitude Ia.

[0149] Based on the detailed description of this embodiment above, the following effects can be obtained.

[0150] There are concerns that by simultaneously performing temperature control and motor 10 drive control, the neutral point current IMr flowing through the first battery 31 and the second battery 32 to heat up does not flow in a sinusoidal pattern, resulting in reduced efficiency of temperature control. Additionally, there are concerns about reduced controllability of the motor 10.

[0151] There are concerns that by simultaneously implementing temperature control and external charging control for charging the first battery 31 and the second battery 32 by the low-voltage charger 230, the neutral point current IMr does not flow in a sinusoidal pattern, thus reducing the efficiency of the temperature control. Additionally, there are concerns that by adding alternating current to the direct current flowing to the first battery 31 and the second battery 32, the charging efficiency of the first battery 31 and the second battery 32 is reduced.

[0152] Therefore, in this embodiment, if it is determined that the energizing rate α, as expressed by the above mathematical formula (eq1), is greater than 1, a limit control is performed. Here, the energizing rate α is the voltage at neutral point O relative to the power supply voltage V. bat The ratio. In the limiting control, in the heating / drive mode, a condition is added to make the energization rate α less than 1, and the neutral point command current IM* is calculated by reducing the magnitude of the current vector or reducing the amplitude Ia. Additionally, in the heating / charging mode, a condition is added to make the energization rate α less than 1, and the neutral point command current IM* is calculated by reducing the charging power of the second battery 32 or reducing the amplitude Ia. Therefore, in the heating / drive mode, the reduction in heating control efficiency or the reduction in motor 10 controllability can be suppressed. Furthermore, in the heating / charging mode, the reduction in heating control efficiency or the reduction in charging efficiency of the first battery 31 and the second battery 32 can be suppressed.

[0153] When the priority determination unit 142 determines whether a heating requirement or a drive requirement exists, it prioritizes either the heating requirement or the drive requirement. Therefore, in the case of priority heating, a decrease in the amplitude Ia of the neutral point command current IM* can be suppressed; or in the case of priority drive, a decrease in the magnitude of the current vector flowing through the armature winding 11 can be suppressed. Furthermore, when the priority determination unit 142 determines whether a heating requirement or an external charging requirement exists, it prioritizes either the heating requirement or the external charging requirement. Therefore, in the case of priority heating, a decrease in the amplitude Ia can be suppressed; or in the case of priority charging, a decrease in the charging power of the second battery 32 can be suppressed.

[0154] <Second Implementation Method>

[0155] Hereinafter, with reference to the accompanying drawings, the second embodiment will be described focusing on the differences from the first embodiment. In this embodiment, as... Figure 12 As shown, connection path 73 electrically connects the neutral point O of armature winding 11 to the high-potential side intermediate terminal BH. The high-potential side intermediate terminal BH is located on the path connecting the battery-to-battery switch 50 to the negative terminal of the first battery 31. Additionally, bypass switch 61 connects the positive terminal of the second battery 32 to the high-potential side path 22H. The first end of the neutral point capacitor 75 is connected to the portion of 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 the portion of the high-potential side path 22H closer to the inverter 20 side compared to the high-potential side main switch SMRH.

[0156] In this embodiment, the inter-terminal voltage (e.g., rated voltage) of the first battery 31 is lower than the inter-terminal voltage (e.g., rated voltage) of the second battery 32.

[0157] Next, the external charging control of this embodiment will be described. Figure 13 The control states of each switch are shown when using external charging control with 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 battery room 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 charges the second battery 32.

[0158] In the external charging control based on the low-voltage charger 210, the motor ECU 100 performs switching control that alternately turns on the upper and lower arm switches (equivalent to "object switches") of at least one phase, or performs switching control of the lower arm switch (equivalent to "object switches") of at least one phase while all the upper arm switches SUH, SVH, and SWH of the inverter 20 are off, thereby reducing the output voltage of the low-voltage charger 210 and supplying it to the first battery 31. Specifically, the motor ECU 100 performs step-down control, which is the aforementioned switching control used to control the neutral point capacitor voltage VN to the target charging voltage. This charges the first battery 31. Since the inter-terminal voltage of the first battery 31 is lower than that of the second battery 32, the target charging voltage of the first battery 31 is lower than that of the second battery 32.

[0159] In this embodiment, similarly to the first embodiment, the motor ECU 100 executes either a boost / drive mode or a boost / charge mode. In this embodiment, when executing the boost / drive mode, the neutral point voltage VO is represented by the following formula (eq6).

[0160] [Mathematical Expression 6]

[0161]

[0162] In the above formula (eq6), VH is the inter-terminal voltage of the first battery 31.

[0163] From the above equations (eq1) and (eq6), we can derive the following equation (eq7).

[0164] [Mathematical Expression 7]

[0165]

[0166] The parameter calculation unit 143 calculates the current carrying rate α based on the above formula (eq7). The parameter calculation unit 143 can use the detection value of the first voltage sensor 85A as VH.

[0167] In this embodiment, when performing boost / charge mode during low-voltage charging, the neutral point voltage VO is represented by the following equation (eq8).

[0168] [Mathematical Expression 8]

[0169]

[0170] In the above equation (eq8), R bat The impedance of the first battery 31.

[0171] From the above equations (eq1) and (eq8), we can derive the following equation (eq9).

[0172] [Mathematical Expression 9]

[0173]

[0174] The parameter calculation unit 143 calculates the power-up rate α of the heating / charging mode during low-voltage charging based on the above formula (eq9). The parameter calculation unit 143 can use the detection value of the first voltage sensor 85A as VH.

[0175] According to the above-described embodiment, the same effect as the first embodiment can be achieved.

[0176] <Other Implementation Methods>

[0177] Furthermore, the above-described embodiments can be implemented with the following modifications.

[0178] exist Figure 11 If it is determined in step S15 that the energization rate α is greater than 1, step S17 can be skipped and step S19 can be executed instead.

[0179] exist Figure 11 If it is determined in step S22 that the energization rate α is greater than 1, step S24 can be skipped and step S26 can be executed instead.

[0180] The method for setting the neutral point command current IM* is not limited to Figure 8 The method shown. In a period Tc, at the zero-crossing time relative to the neutral point command current IM*, while satisfying the point-symmetric relationship between the positive and negative neutral point command currents IM*, the positive and negative neutral point command currents IM* can also be set as trapezoidal waves or rectangular waves respectively.

[0181] Furthermore, the method for setting the neutral point command current IM* is not limited to the method that satisfies the aforementioned point symmetry relationship. For example, in one cycle Tc, the period from the first zero-crossing time C1 to the second zero-crossing time C2 of the neutral point command current IM* can be different from the period from the second zero-crossing time C2 to the third zero-crossing time C3 of the neutral point command current IM*, and the neutral point command current IM* can be set in such a way that the area S1 of the first region and the area S2 of the second region are equal. Even in this case, it is possible to make the charging and discharging currents of the first battery 31 and the second battery 32 match in one cycle Tc.

[0182] In the power conversion device of the first embodiment, it is also possible to... Figure 14As shown, the battery compartment switch 50 and the bypass switch 60 are not equipped in the power conversion device. Alternatively, at least one of the battery compartment switch 50 and the bypass switch 60 may not be equipped in the power conversion device. When the battery compartment switch 50 is not equipped in the power conversion device, the negative terminal of the first battery 31 is electrically connected to the positive terminal of the second battery 32.

[0183] The threshold for the power efficiency α can be set to a value less than 1. For example, the threshold for the power efficiency α is a value greater than or equal to 0.9 and less than 1, or a value greater than or equal to 0.95 and less than 1.

[0184] exist Figure 11 In the flowchart shown, the neutral point voltage VO can be used relative to the supply voltage V instead of the current-carrying rate α. bat The relevant value of the ratio. For example, the relevant value is the voltage utilization rate m. The voltage utilization rate m is represented, for example, by the following formula (eq10).

[0185] [Mathematical Expression 10]

[0186]

[0187] The parameter calculation unit 143 calculates the voltage utilization rate m based on the above formula (eq10). The parameter calculation unit 143 can use, for example, the d-axis voltage Vd calculated in the d-axis control unit 122d as Vd. The parameter calculation unit 143 can also use, for example, the q-axis voltage Vq calculated in the q-axis control unit 122q as Vq.

[0188] Additionally, for example, the relevant value is the modulation rate. The motor ECU 100 may use, for example, the maximum value of the U-W phase modulation rates Mu, Mv, and Mw calculated in the U-W phase modulation section 135U-135W as the modulation rate.

[0189] In the above embodiments, either the first motor-side switch 71 or the second motor-side switch 72 may not be provided in the power conversion device. Alternatively, neither the first motor-side switch 71 nor the second motor-side switch 72 may be provided in the power conversion device.

[0190] The switch for inverter 20 is not limited to IGBTs; for example, it could be an N-channel MOSFET with a body diode. 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.

[0191] Alternatively, the high-potential side main switch SMRH may not be required.

[0192] Alternatively, the low-potential side main switch SMRL can be replaced by a series connection of the pre-charge main switch SMRP and the pre-charge resistor 40 connected in parallel to the high-potential side main switch SMRH. Alternatively, in this case, the low-potential side main switch SMRL may not be required.

[0193] Alternatively, fuses 41 and 42 can be omitted.

[0194] As a motor, it is not limited to a star-connected motor, but can also be a delta-connected motor. Furthermore, as a motor and inverter, it is not limited to a three-phase motor and inverter, but can also be a two-phase or four-phase or higher motor and inverter. Additionally, as a motor, it is not limited to a permanent magnet synchronous motor with permanent magnets as magnetic field poles on the rotor, but can also be a wound-magnetic synchronous motor with magnetic field windings as magnetic field poles on the rotor. In this case, both magnetic field windings and permanent magnets can be equipped on the rotor simultaneously. Furthermore, as a motor, it is not limited to a synchronous motor, but can also be an induction motor.

[0195] As a control device for performing boost / drive mode or boost / charge mode, it is not limited to the motor ECU100. For example, it can also be executed by the cooperation of multiple control devices such as the battery ECU90, EVECU110 and motor ECU100.

[0196] The energy storage unit that is charged based on an external charger is not limited to a battery. For example, it can also be an energy storage unit with a large-capacity electrical double-layer capacitor, or a combination of a battery and an electrical double-layer capacitor.

[0197] The mobile body carrying the power conversion device is not limited to vehicles; it can also be an aircraft or a ship. Furthermore, the device can be mounted not only on mobile bodies but also on stationary installations.

[0198] The control device and method described in this disclosure can also be implemented by a dedicated computer, which is provided by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control device and method described in this disclosure can also be implemented by a dedicated computer, which is provided by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control device and method described in this disclosure can also be implemented by one or more dedicated computers, which are composed of a combination of a processor and memory programmed to perform one or more functions and a processor configured with one or more hardware logic circuits. In addition, the computer program can be stored as instructions executable by the computer on a computer-readable, non-transitory tangible storage medium.

[0199] This disclosure is described based on embodiments, but it is to be understood that this disclosure is not limited to these embodiments and structures. This disclosure also includes various modifications and variations within the same scope. Furthermore, various combinations and arrangements, and consequently other combinations and arrangements that include only one element, or more or fewer elements, also fall within the scope and spirit of this disclosure.

Claims

1. A power conversion device, comprising: Inverter (20), which has multi-phase upper arm switches, lower arm switches (SUH~SWL); and The motor (10) has an armature winding (11U~11W) electrically connected to the low-potential side terminal of the upper arm switch of each phase and the high-potential side terminal of the lower arm switch of each phase. Its features are, have: A high-potential side path (22H) electrically connects the positive terminal of the first energy storage unit (31) to the high-potential side terminal of the upper arm switch; The low-potential side path (22L) electrically connects the negative terminal of the second energy storage unit (32) to the low-potential side terminal of the lower arm switch. Connection path (73), which electrically connects the negative terminal of the first energy storage unit or the positive terminal of the second energy storage unit to the armature winding; and Control device (100). The control device includes: A temperature rise determination unit (140) determines whether there is a temperature rise requirement that causes an alternating heating current to flow between the first energy storage unit and the second energy storage unit via the armature winding and the connection path. The action determination unit (141) determines whether there is an action requirement that causes a DC operating current to flow through at least one of the first energy storage unit and the second energy storage unit. When the switch control unit (145) determines that there is a heating requirement and an operation requirement, the switch control unit performs switch control of the upper arm switch and the lower arm switch so that the heating current flows between the first energy storage unit and the second energy storage unit, and the operation current flows through at least one of the first energy storage unit and the second energy storage unit. as well as A threshold determination unit (144) determines whether a determination parameter (α) is below a threshold value. This determination parameter is either the ratio of the neutral point voltage of the armature winding to the voltage difference between the high-potential side path and the low-potential side path, or a related value of the ratio. If the determination parameter is determined to be greater than the threshold, the switch control unit performs a restriction control, which is a switch control that adds a condition to make the determination parameter fall below the threshold.

2. The power conversion device according to claim 1, characterized in that, Compared to the case where the determination parameter is below the threshold, the switch control unit reduces the amplitude of the heating current in the limiting control.

3. The power conversion device according to claim 1, characterized in that, Compared to the case where the determination parameter is below the threshold, the switch control unit reduces the magnitude of the current vector flowing to the armature winding in the restriction control.

4. The power conversion device according to any one of claims 1 to 3, characterized in that, The system includes a priority determination unit (142) that determines whether to prioritize the heating requirement or the action requirement. The action requirement refers to the driving requirement of the rotor (13) of the motor. When the heating requirement is prioritized, compared to when the determination parameter is below the threshold, the switch control unit reduces the magnitude of the current vector flowing to the armature winding in the limiting control. When the action requirement is determined to be prioritized, the switch control unit reduces the amplitude of the heating current in the limiting control compared to the case where the determination parameter is below the threshold.

5. The power conversion device according to any one of claims 1 to 3, characterized in that, The system includes a priority determination unit (142) that determines whether to prioritize the heating requirement or the action requirement. The aforementioned operational requirements refer to the external charging requirements when the external charger (200, 210) is electrically connected to the high-potential side path and the low-potential side path. When the heating requirement is prioritized, compared to when the determination parameter is below the threshold, the switch control unit reduces the charging power of the second and first energy storage units, which are charged by the external charger via the connection path, in the limiting control. When the action requirement is determined to be prioritized, the switch control unit reduces the amplitude of the heating current in the limiting control compared to the case where the determination parameter is below the threshold.

6. The power conversion device according to any one of claims 1 to 3, characterized in that, The action determination unit determines whether the action requirement includes a rotation drive requirement for the rotor (13) of the motor. When it is determined that there is a heating requirement and a rotation drive requirement, the switch control unit performs the switch control so that the heating current flows between the first energy storage unit and the second energy storage unit, and the operating current flows from the series connection of the first energy storage unit and the second energy storage unit to the inverter.

7. The power conversion device according to claim 4, characterized in that, The action determination unit determines whether the action requirement includes a rotation drive requirement for the rotor (13) of the motor. When it is determined that there is a heating requirement and a rotation drive requirement, the switch control unit performs the switch control so that the heating current flows between the first energy storage unit and the second energy storage unit, and the operating current flows from the series connection of the first energy storage unit and the second energy storage unit to the inverter.

8. The power conversion device according to any one of claims 1 to 3, characterized in that, The action determination unit determines whether the action request exists because an external charger (200, 210) is electrically connected to both the high-potential side path and the low-potential side path. When it is determined that there is a heating requirement and an external charging requirement, the switch control unit performs the switch control so that the heating current flows between the first energy storage unit and the second energy storage unit, and the external charger charges at least one of the first energy storage unit and the second energy storage unit.

9. The power conversion device according to claim 5, characterized in that, The action determination unit determines whether the action request exists because an external charger (200, 210) is electrically connected to both the high-potential side path and the low-potential side path. When it is determined that there is a heating requirement and an external charging requirement, the switch control unit performs the switch control so that the heating current flows between the first energy storage unit and the second energy storage unit, and the external charger charges at least one of the first energy storage unit and the second energy storage unit.

10. A program applied to a power conversion device, the power conversion device comprising: Inverter (20), which has multi-phase upper arm switches, lower arm switches (SUH~SWL); and Motor (10), having an armature winding (11U~11W) electrically connected to the low-potential side terminal of the upper arm switch of each phase and the high-potential side terminal of the lower arm switch of each phase, characterized in that, The power conversion device includes: A high-potential side path (22H) electrically connects the positive terminal of the first energy storage unit (31) to the high-potential side terminal of the upper arm switch; The low-potential side path (22L) electrically connects the negative terminal of the second energy storage unit (32) to the low-potential side terminal of the lower arm switch. Connection path (73), which electrically connects the negative terminal of the first energy storage unit or the positive terminal of the second energy storage unit to the armature winding; and Computer Science (101) The program causes the computer to execute: The temperature rise determination process determines whether there is a temperature rise requirement that would cause the AC temperature rise current to flow between the first energy storage unit and the second energy storage unit through the armature winding and the connection path. Action determination processing determines whether there is an action requirement that causes a DC operating current to flow through at least one of the first energy storage unit and the second energy storage unit; The control process, upon determining that both the heating requirement and the action requirement exist, controls the switching of the upper arm switch and the lower arm switch to allow the heating current to flow between the first and second energy storage units, and the action current to flow through at least one of the first and second energy storage units; and The threshold determination process determines whether the determination parameter (α) is below a threshold value. This determination parameter is either the ratio of the neutral point voltage of the armature winding to the voltage difference between the high-potential side path and the low-potential side path, or a related value of the ratio. In the control process, if it is determined that the determination parameter is greater than the threshold, a restriction control is performed. This restriction control is the switch control with an added condition that causes the determination parameter to be below the threshold.

11. A control method for a power conversion device, applied to the power conversion device, the power conversion device comprising: Inverter (20), which has multi-phase upper arm switches, lower arm switches (SUH~SWL); and Motor (10), having an armature winding (11U~11W) electrically connected to the low-potential side terminal of the upper arm switch of each phase and the high-potential side terminal of the lower arm switch of each phase, characterized in that, The power conversion device includes: A high-potential side path (22H) electrically connects the positive terminal of the first energy storage unit (31) to the high-potential side terminal of the upper arm switch; A low-potential side path (22L) electrically connects the negative terminal of the second energy storage unit (32) to the low-potential side terminal of the lower arm switch; and Connection path (73) electrically connects the negative terminal of the first energy storage unit or the positive terminal of the second energy storage unit to the armature winding. The control method comprises: In the heating step, it is determined whether there is a heating requirement that would allow the alternating heating current to flow between the first energy storage unit and the second energy storage unit via the armature winding and the connection path. The action determination step determines whether there is an action requirement that causes a DC operating current to flow through at least one of the first energy storage unit and the second energy storage unit; The control step involves, when it is determined that there is a heating requirement and an action requirement, controlling the switching of the upper arm switch and the lower arm switch so that the heating current flows between the first energy storage unit and the second energy storage unit, and the action current flows through at least one of the first energy storage unit and the second energy storage unit. as well as The threshold determination step determines whether the determination parameter (α) is below a threshold. This determination parameter is either the ratio of the neutral point voltage of the armature winding to the voltage difference between the high-potential side path and the low-potential side path, or a related value of the ratio. In the control step, if it is determined that the determination parameter is greater than the threshold, a restriction control is performed. This restriction control is the switch control with an added condition that causes the determination parameter to be below the threshold.

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