Control device, control method, and recording medium

Abstract

Provided is a control device for controlling a drive system of a vehicle comprising a plurality of batteries, at least one motor that has one output shaft, at least two sets of multi-phase windings that are arranged around the one output shaft, and a plurality of inverters that are respectively connected to the at least two sets of multi-phase windings. Said control device acquires battery conditions of the plurality of batteries, acquires a traveling condition of the vehicle, and determines driving of each of the plurality of inverters as either power running or regeneration on the basis of the acquired battery conditions of the plurality of batteries and traveling condition of the vehicle.

Description

Control Device, Control Method, and Recording Medium

[0001] The present disclosure relates to a control device, a control method, and a recording medium.

[0002] Techniques for controlling the charge states of a plurality of batteries mounted on a vehicle are known.

[0003] For example, in Patent Document 1, there is a charge / discharge control device that controls the power transfer between a rotating electrical machine having a plurality of phase windings and a first voltage source and a second voltage source. The charge / discharge control device includes a first inverter connected to one end of the winding and the first voltage source, a second inverter connected to the other end of the winding and the second voltage source, and a control unit having a drive control unit that controls the driving of the rotating electrical machine by controlling the first inverter and the second inverter. At least one of the first voltage source and the second voltage source is a power storage device capable of charging the regenerative power of the rotating electrical machine. The drive control unit controls the first inverter and the second inverter based on the remaining charge amount so that the remaining charge amount of the power storage device reaches a target value. A charge / discharge control device is disclosed.

[0004] Also, in Patent Document 2, there are a first inverter connected to the positive electrode bus and the negative electrode bus of a first power source, a second inverter connected to the positive electrode bus and the negative electrode bus of a second power source, a rotating electrical machine connected to the first inverter and the second inverter, a charger connected to the first power source to supply external power, and a control device. The control device controls the operations of the first inverter and the second inverter in a state where the rotating electrical machine is stationary, and includes an external power charging unit that transmits the power supplied from the first power source side to the second power source through the first inverter, the rotating electrical machine, and the second inverter to charge the second power source. When the second state of charge (SOC) indicating the charge state of the second power source is within a chargeable range and the first SOC indicating the charge state of the first power source has not decreased until charging is required, a power charging unit that preferentially allocates the power of the rotating electrical machine to charge the second power source is included. A rotating electrical machine control system is disclosed.

[0005] Patent Document 3 also describes a first energy storage unit that can be charged by power from a charger, a second energy storage unit that can be charged in parallel with the first energy storage unit by power from the charger, a first capacitor connected in parallel with the first energy storage unit, a second capacitor connected in parallel with the second energy storage unit, a switch that can switch the connection between the charger, the first energy storage unit and the first capacitor, the second energy storage unit and the second capacitor, a first voltage detection unit that detects the voltage of the first energy storage unit, the voltage of the second energy storage unit, and the first energy storage unit voltage and the second energy storage unit A power supply system is disclosed which includes a control unit that controls the amount of charge of the first and second energy storage units based on the voltage of the units, wherein when charging by the charger is not being performed, the control unit controls the amount of charge of the first and second energy storage units so that the voltage of the first energy storage unit is less than or equal to the voltage of the second energy storage unit, and when charging by the charger is being performed, if the voltage difference between the voltage of the first energy storage unit and the voltage of the second energy storage unit is greater than or equal to a voltage determination threshold, the switch is opened and the first energy storage unit is charged on one side, and if the voltage difference is less than the voltage determination threshold, the switch is closed and the first and second energy storage units are charged in parallel.

[0006] Japanese Patent Publication No. 2019-126210, Japanese Patent Publication No. 2020-018147, Japanese Patent Publication No. 2020-005389

[0007] The connection state of batteries installed in a vehicle, such as series or parallel connection, significantly affects the characteristics of the vehicle's drive system. Series connection allows for higher voltage handling, increasing the vehicle's top speed. Conversely, parallel connection allows for higher current output, increasing the vehicle's output torque. Therefore, being able to switch between series and parallel battery connections allows the vehicle to utilize both characteristics, enabling it to adapt to a wider range of situations.

[0008] Ideally, the State of Charge (SOC) of each battery should be similar in order to suppress battery degradation and match battery characteristics. However, the degree of degradation differs from battery to battery, and even with the same usage, the SOC may differ between batteries. Therefore, it is desirable to quickly equalize the SOC between batteries when switching between series and parallel connections. In contrast, with conventional technology, adjusting the SOC when the SOCs of batteries differ takes time, and there was room for improvement in the speed of SOC adjustment required when switching between series and parallel connections.

[0009] In light of these circumstances, the purpose of this disclosure is to provide a technology that enables rapid adjustment of the State of Control (SOC) between multiple batteries mounted in a vehicle.

[0010] A control device according to one embodiment of the present disclosure is a control device for a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, the control device comprising: one or more processors; and one or more memories communicately connected to the one or more processors, wherein the one or more processors acquire the battery state of the plurality of batteries, acquire the running state of the vehicle, and determine the driving of each of the plurality of inverters from among powering and regenerating based on the acquired battery state of the plurality of batteries and the running state of the vehicle.

[0011] A control method according to one embodiment of the present disclosure is a control method for a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, wherein a computer acquires the battery state of the plurality of batteries; acquires the driving state of the vehicle; and determines, based on the acquired battery state of the plurality of batteries and the driving state of the vehicle, to drive each of the plurality of inverters from among powering and regenerating.

[0012] A non-temporary tangible recording medium recording a control program according to one embodiment of the present disclosure is a recording medium recording a control program for a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, wherein the recording medium causes a computer to perform the following actions: acquire the battery status of the plurality of batteries; acquire the driving status of the vehicle; and determine whether to drive each of the plurality of inverters from among powering and regenerating based on the acquired battery status of the plurality of batteries and the driving status of the vehicle.

[0013] According to one embodiment of the present disclosure, the SOC (State of Control) between multiple batteries mounted in a vehicle can be quickly adjusted.

[0014] This is a schematic diagram showing an example of the configuration of a vehicle equipped with a control device according to one embodiment of the present disclosure. This is a circuit diagram illustrating a plurality of inverters and motors according to one embodiment of the present disclosure. This is a circuit diagram illustrating a first connection state of a plurality of batteries and a plurality of inverters according to one embodiment of the present disclosure. This is a circuit diagram illustrating a second connection state of a plurality of batteries and a plurality of inverters according to one embodiment of the present disclosure. This is a circuit diagram illustrating a third connection state of a plurality of batteries and a plurality of inverters according to one embodiment of the present disclosure. This is a block diagram illustrating an example of the configuration of a control device according to one embodiment of the present disclosure. This is a flowchart illustrating an example of the operation of a control device according to one embodiment of the present disclosure. This is a flowchart illustrating in detail the SOC adjustment process shown in Figure 7. This is a diagram illustrating the SOC adjustment process by adjusting the driving force. This is a diagram illustrating the SOC adjustment process by regeneration and powering.

[0015] Preferred embodiments of this disclosure will be described in detail below with reference to the attached drawings. In this specification and the drawings, components having substantially the same functional configuration are denoted by the same reference numerals, and redundant descriptions will be omitted.

[0016] (1. Overall Vehicle Configuration) Referring to Figure 1, an example of the overall configuration of a vehicle 1 equipped with a control device according to one embodiment of the present disclosure will be described.

[0017] Vehicle 1 is a two-wheel drive four-wheeled automobile that transmits the drive torque output from a drive motor 10, which serves as a driving force source that generates the drive torque for vehicle 1, to the front wheels.

[0018] Furthermore, the combination of drive wheels and the drive method are not limited. For example, vehicle 1 may be a rear-wheel drive vehicle or a four-wheel drive vehicle. Also, vehicle 1 may be an electric vehicle equipped with two drive motors, including a front-wheel drive motor and a rear-wheel drive motor. Also, vehicle 1 may be an electric vehicle equipped with a drive motor corresponding to each wheel.

[0019] The drive system 2 provided in the vehicle 1 includes a drive motor 10, a plurality of inverters 20, a converter 30, and a plurality of batteries 40. In the following description, a first inverter 20a and a second inverter 20b may be used as examples of the plurality of inverters 20, and a first battery 40a and a second battery 40b may be used as examples of the plurality of batteries 40, but this disclosure is not limited thereto.

[0020] The drive motor 10 outputs drive torque which is transmitted to the front wheels via the differential mechanism 5 and the front wheel drive shaft 6F. Here, the drive motor 10 is a motor having one output shaft and including at least two sets of multiphase windings arranged around the one output shaft. Referring also to Figure 2, the drive motor 10 may be a single motor including a first stator 11, a second stator 12, and a rotor 13, and may further be configured as a three-phase AC motor. In this case, the rotor 13 rotates due to the rotating magnetic field formed by the supply of three-phase AC power generated by the first inverter 20a to the first stator 11, and drive torque is output. Also, the rotor 13 rotates due to the rotating magnetic field formed by the supply of three-phase AC power generated by the second inverter 20b to the second stator 12, and drive torque is output. As will be described in detail later, the drive motor 10 can output a portion of the output obtained from the rotor 13, which is rotated by the three-phase AC power generated by the first inverter 20a, as drive torque, and output the remainder of the output obtained from the rotating rotor 13 as regenerative power to the second inverter 20b. Similarly, the drive motor 10 can output a portion of the output obtained from the rotor 13, which is rotated by the three-phase AC power generated by the second inverter 20b, as drive torque, and output the remainder of the output obtained from the rotating rotor 13 as regenerative power to the first inverter 20a. Furthermore, the drive motor 10 can also perform regenerative power generation when the first stator 11 and the second stator 12 are not supplied with three-phase AC power, by having the rotor 13 rotate in response to the rotational torque of the front wheels transmitted via the front wheel drive shaft 6F. The drive motor 10 is a motor having one output shaft (rotor shaft) and including at least two sets of multiphase windings arranged around the one output shaft (rotor shaft). It may be an axial gap motor or a radial gap motor.

[0021] Referring to Figure 1, the multiple inverters 20 convert DC power supplied from the multiple batteries 40 into multiphase AC power and supply it to the drive motor 10. The multiple inverters 20 also convert the multiphase AC power generated by the regeneration of the drive motor 10 into DC power and supply it to the converter 30. The operation of the multiple inverters 20 is controlled by the control device 50. In this embodiment, the multiple inverters 20 are each connected to at least two sets of multiphase windings arranged around one output shaft of the drive motor 10. The multiple inverters 20 will now be described in detail with reference to Figure 2.

[0022] Referring to Figure 2, a case will be described in which a plurality of inverters 20 include a first inverter 20a and a second inverter 20b, a plurality of batteries 40 include a first battery 40a and a second battery 40b, and the polyphase winding is a three-phase winding consisting of u-phase, v-phase, and w-phase. However, the disclosure is not limited thereto.

[0023] The first inverter 20a includes a pair of busbars 21a connected to the high-voltage (positive) and low-voltage (negative) output terminals of the first battery 10a via a converter 30, and three upper arms 22au, 22av, 22aw and lower arms 23au, 23av, 23aw connected to the pair of busbars 21a. Each of the three upper arms 22au, 22av, 22aw includes a switching element 24au, 24av, 24aw and diodes 25au, 25av, 25aw connected in antiparallel to the switching elements 24au, 24av, 24aw. Each of the three lower arms 23au, 23av, and 23aw includes switching elements 26au, 26av, and 26aw, and diodes 27au, 27av, and 27aw connected in antiparallel to the switching elements 26au, 26av, and 26aw. The windings of each phase (u-phase, v-phase, and w-phase) of the drive motor 10 are connected between each upper arm 22au, 22av, and 22aw and the lower arms 23au, 23av, and 23aw via output lines 28au, 28av, and 28aw. The switching elements 24au, 24av, and 24aw and 26au, 26av, and 26aw may be, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors), but this disclosure is not limited to these. However, the converter 30 can be omitted in this circuit.

[0024] During powering, the first inverter 20a controls the switching elements 24au, 24av, 24aw of the upper arms 22au, 22av, 22aw and the switching elements 26au, 26av, 26aw of the lower arms 23au, 23av, 23aw, respectively, based on a control signal from the control device 50 described later, to generate three-phase AC power from the DC power swept from the first battery 40a. This three-phase AC power is supplied to the windings of each phase (u-phase, v-phase, w-phase) of the first stator 11 via their respective output lines 28au, 28av, 28aw. This creates a rotating magnetic field, causing the rotor 13 to rotate and outputting drive torque. Meanwhile, the first inverter 20a converts the three-phase AC power (regenerative power) obtained by the rotation of the rotor 13 into DC power by controlling the on / off state of switching elements 24au, 24av, 24aw and 26au, 26av, 26aw during regeneration. This charges the first battery 40a. Diodes 25au, 25av, 25aw and 27au, 27av, 27aw are used when the back electromotive force corresponding to the rotational speed of the rotor 13 becomes higher than that of the first battery 40a.

[0025] The second inverter 20b includes a pair of busbars 21b connected to the high-voltage (positive) and low-voltage (negative) output terminals of the second battery 40b via a converter 30, and three upper arms 22bu, 22bv, 22bw and lower arms 23bu, 23bv, 23bw connected to the pair of busbars 21b. Each of the three upper arms 22bu, 22bv, 22bw includes a switching element 24bu, 24bv, 24bw and diodes 25bu, 25bv, 25bw connected in antiparallel to the switching elements 24bu, 24bv, 24bw. Each of the three lower arms 23bu, 23bv, and 23bw includes a switching element 26bu, 26bv, and 26bw, and diodes 27bu, 27bv, and 27bw connected in antiparallel to the switching elements 26bu, 26bv, and 26bw. The windings of each phase (u-phase, v-phase, and w-phase) of the drive motor 10 are connected between each upper arm 22bu, 22bv, and 22bw and the lower arms 23bu, 23bv, and 23bw via output lines 28bu, 28bv, and 28bw. The switching elements 24bu, 24bv, and 24bw and 26bu, 26bv, and 26bw may be, for example, MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) or IGBTs (Insulated Gate Bipolar Transistors), but this disclosure is not limited to these. However, the converter 30 can be omitted in this circuit.

[0026] During powering, the second inverter 20b controls the switching elements 24bu, 24bv, 24bw of the upper arms 22bu, 22bv, 22bw and the switching elements 26bu, 26bv, 26bw of the lower arms 23bu, 23bv, 23bw based on a control signal from the control device 50, thereby generating three-phase AC power from the DC power swept from the second battery 40b. This three-phase AC power is supplied to the windings of each phase (u-phase, v-phase, w-phase) of the second stator 12 via their respective output lines 28bu, 28bv, 28bw. This creates a rotating magnetic field, causing the rotor 13 to rotate and outputting drive torque. Meanwhile, the second inverter 20b converts the three-phase AC power (regenerative power) obtained by the rotation of the rotor 13 into DC power by controlling the on / off states of the switching elements 24bu, 24bv, 24bw and 26bu, 26bv, 26bw during regeneration. This charges the second battery 40b. Diodes 25bu, 25bv, 25bw and 27bu, 27bv, 27bw are used when the back electromotive force corresponding to the rotational speed of the rotor 13 becomes higher than that of the second battery 40b.

[0027] The converter 30 boosts the voltage of the power regenerated by the drive motor 10 to the required charging voltage of the multiple batteries 40 and supplies it to the multiple batteries 40. The boost circuit may also have the function of boosting or lowering the output voltage of the multiple batteries 40 and supplying it to the inverter 20. The drive of the converter 30 is controlled by the control device 50.

[0028] Multiple batteries 40 supply power to the drive motor 10. Each of the multiple batteries 40 may be a secondary battery such as a lithium-ion battery or a solid-state battery with a rated voltage of 200V, but this disclosure is not limited to these. Each of the multiple batteries 40 is equipped with a known or arbitrary voltage sensor (not shown) capable of detecting the battery voltage. In addition to the voltage sensor, each of the multiple batteries 40 may be equipped with a known or arbitrary current sensor (not shown) capable of detecting the battery current.

[0029] Referring to Figures 3 to 5, the connection states of the multiple inverters 20 and multiple batteries 40 will be described in detail. Referring to Figure 3, in the first connection state, the opening and closing of the switching elements SW1, SW2, and SW3 are appropriately controlled by the control device 50 so that the first battery 40a and the second battery 40b are connected in series to the first inverter 20a connected to the first stator 11 and the second inverter 20b connected to the second stator 12. The first inverter 20a and the second inverter 20b are connected in parallel to each other. During powering, the first inverter 20a converts the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the first stator 11. As a result, the rotor 13 rotates and a driving torque is output. Meanwhile, the first inverter 20a converts the three-phase AC power (regenerative power) obtained by the rotor 13 rotating in response to the rotational torque of the front wheels during regeneration into DC power and supplies this DC power to the first battery 40a and the second battery 40b. This charges the first battery 40a and the second battery 40b. Furthermore, the second inverter 20b converts the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power during powered operation and supplies this three-phase AC power to the second stator 12. This causes the rotor 13 to rotate and output drive torque. Meanwhile, the second inverter 20b converts the three-phase AC power (regenerative power) obtained by the rotor 13 rotating in response to the rotational torque of the front wheels during regeneration into DC power and supplies this DC power to the first battery 40a and the second battery 40b. This charges the first battery 40a and the second battery 40b. The operation of the first inverter 20a and the second inverter 20b is controlled by the control device 50. The switching elements SW1, SW2, and SW3 may be, for example, excitation-type mechanical relays, but the disclosure is not limited to these, and may also be semiconductor relays such as field-effect transistors.

[0030] Referring to Figure 4, in the second connection state, the switching elements SW1, SW2, and SW3 are appropriately controlled by the control device 50 to open and close, thereby independently connecting the first battery 40a to the first inverter 20a connected to the first stator 11, and independently connecting the second battery 40b to the second inverter 20b connected to the second stator 12. During powering, the first inverter 20a converts the DC power swept from the first battery 40a into three-phase AC power and supplies this three-phase AC power to the first stator 11. As a result, when the rotor 13 rotates, all or part of the output obtained by the rotation of the rotor 13 is output as drive torque. On the other hand, during regeneration, the first inverter 20a converts the three-phase AC power (regenerative power) obtained by the rotation of the rotor 13 into DC power and supplies this DC power to the first battery 40a. As a result, the first battery 40a is charged. Furthermore, during powering, the second inverter 20b converts the DC power swept from the second battery 40b into three-phase AC power and supplies this three-phase AC power to the second stator 12. As a result, when the rotor 13 rotates, all or part of the output obtained from the rotation of the rotor 13 is output as drive torque. On the other hand, during regeneration, the second inverter 20b converts the three-phase AC power (regenerative power) obtained from the rotation of the rotor 13 into DC power and supplies this DC power to the second battery 40b. As a result, the second battery 40b is charged. As will be described in detail later, the driving of the first inverter 20a and the second inverter 20b is controlled by the control device 50.

[0031] Furthermore, even in the second connection state, the drive motor 10 can also perform regenerative power generation by rotating the rotor 13 in response to the rotational torque of the front wheels transmitted via the front wheel drive shaft 6F, when three-phase AC power is not supplied to the first stator 11 and the second stator 12. At this time, the inverter control unit 67 may control the driving of the first inverter 20a and the second inverter 20b, respectively, so that the amount of regeneration from the high SOC side of the first battery 40a and the second battery 40b is greater than the amount of regeneration from the low SOC side.

[0032] Referring to Figure 5, in the third connection state, the opening and closing of the switching elements SW1, SW2, and SW3 are appropriately controlled by the control device 50, so that the first battery 40a and the second battery 40b are connected in parallel to the first inverter 20a connected to the first stator 11 and the second inverter 20b connected to the second stator 12. The first inverter 20a and the second inverter 20b are connected in parallel to each other. During powering, the first inverter 20a converts the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the first stator 11. As a result, the rotor 13 rotates and a driving torque is output. Meanwhile, the first inverter 20a converts the three-phase AC power (regenerative power) obtained by the rotor 13 rotating in response to the rotational torque of the front wheels during regeneration into DC power, and supplies this DC power to the first battery 40a and the second battery 40b. This charges the first battery 40a and the second battery 40b. Furthermore, the second inverter 20b converts the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power during powered operation, and supplies this three-phase AC power to the second stator 12. This causes the rotor 13 to rotate and output drive torque. Meanwhile, the second inverter 20b converts the three-phase AC power (regenerative power) obtained by the rotor 13 rotating in response to the rotational torque of the front wheels during regeneration into DC power, and supplies this DC power to the first battery 40a and the second battery 40b. This charges the first battery 40a and the second battery 40b. The operation of the first inverter 20a and the second inverter 20b is controlled by the control device 50.

[0033] Returning to Figure 1, the brake system provided on the vehicle 1 includes brake devices 7LF, 7RF, 7LR, and 7RR (hereinafter collectively referred to as "brake device 7" unless otherwise specified) provided on each wheel. The brake device 7 applies braking force to each wheel. The brake device 7 may be, for example, a hydraulic brake device. In this case, the hydraulic pressure supplied to each brake device 7 is adjusted by controlling the drive of the hydraulic unit 8 by the vehicle control device 60. The brake device 7 is used in conjunction with regenerative braking by the drive motor 10.

[0034] The steering system provided in vehicle 1 includes an electric steering device 9 mounted on the front wheel drive shaft 6F. The electric steering device 9 includes an electric motor (not shown) and a gear mechanism (not shown), and adjusts the steering angle of the front wheels by being controlled by a vehicle control device 60. The vehicle control device 60 controls the electric steering device 9 based on the steering angle of the steering wheel set by the driver. If vehicle 1 is a vehicle capable of automatic driving control, the vehicle control device 60 controls the electric steering device 9 based on the steering angle of the steering wheel set by the driver during manual driving. On the other hand, during automatic driving, the vehicle control device 60 controls the electric steering device 9 based on a steering angle or steering angular velocity set by a known or arbitrary method.

[0035] The vehicle control device 60 includes one or more electronic control units (ECUs) that control the brake system and steering system provided in the vehicle 1. Note that all or some of the functions of the vehicle control device 60 may be provided in the control device 50.

[0036] Vehicle 1 is equipped with a vehicle state sensor 81 that detects the driving state of vehicle 1. The vehicle state sensor 81 may include, for example, a vehicle speed sensor that detects the vehicle speed of vehicle 1. The vehicle state sensor 81 may also include, for example, an accelerator position sensor that detects the accelerator opening. In addition to these, the vehicle state sensor 81 may also include an acceleration sensor, an angular velocity sensor, a steering angle sensor, a brake stroke sensor, a brake pressure sensor, or an engine speed sensor. The vehicle state sensor 81 transmits a sensor signal indicating the detected information to the vehicle control device 60.

[0037] In addition, the vehicle 1 may be equipped with an ambient environment sensor 83, a GNSS (Global Navigation Satellite System) sensor 85, and a notification device 90.

[0038] The ambient environment sensor 83 may include a front-facing camera and a rear-facing camera. The front-facing camera captures the area in front of the vehicle 1 and generates image data. The rear-facing camera captures the area behind the vehicle 1 and generates image data. The front-facing camera and the rear-facing camera are equipped with image sensors such as CCD (Charged Coupled Devices) or CMOS (Complementary Metal Oxide Semiconductor) and transmit the generated image data to the vehicle control device 60. The front-facing camera may be a stereo camera including a pair of left and right cameras, or it may be a monocular camera. The ambient environment sensor 83 may also include one or more distance measuring sensors from among radar sensors such as LiDAR (Light Detection And Ranging) or millimeter-wave radar and ultrasonic sensors.

[0039] The GNSS sensor 85 receives satellite signals from positioning satellites such as GPS (Global Positioning System) satellites. The GNSS sensor 85 transmits the vehicle 1's position information, which is included in the received satellite signals, to the vehicle control device 60. In addition to the GPS sensor, the GNSS sensor 85 may also be equipped with an antenna that receives satellite signals from other satellite systems that determine the vehicle 1's position.

[0040] The notification device 90 is driven by the vehicle control device 60 and notifies the driver of vehicle 1 of various information by means such as image display or audio output. The notification device 90 includes, for example, a display device provided in the instrument panel and a speaker provided in vehicle 1. The display device may be a display device of a navigation system. The notification device 90 may also include a HUD (Head Up Display) that displays on the front windshield of vehicle 1.

[0041] (2. Control device) The control device 50 according to this embodiment will be described with reference to Figure 6.

[0042] (2-1. Configuration Example) The control device 50 functions as a device for controlling the drive system 2 of the vehicle 1 by having one or more CPUs (Central Processing Units) or other processors execute a computer program. The computer program is a computer program that causes the processor to execute the operations that the control device 50 is to perform, which will be described later. The computer program executed by the processor may be recorded on a recording medium that functions as a memory unit 53, which will be described later, or it may be recorded on a recording medium built into the control device 50 or on any recording medium that can be attached externally to the control device 50.

[0043] The recording medium for storing computer programs may include magnetic media such as hard disks, floppy disks, and magnetic tapes; optical recording media such as CD-ROMs, DVDs, and Blu-ray®; magneto-optical media such as floppy disks; memory elements such as RAM and ROM; flash memory such as USB memory and SSDs; and other media capable of storing programs.

[0044] The control device 50 is connected to the vehicle control device 60 via a dedicated line or communication means such as CAN (Controller Area Network) or LIN (Local Inter Net). In the vehicle 1 shown in FIG. 1, the vehicle state sensor 81 is connected to the control device 50 via the vehicle control device 60, but may be directly connected to the control device 50 via communication means such as a dedicated line or CAN or LIN. Note that part or all of the functions of the control device 50 may be provided in the vehicle control device 60.

[0045] The control device 50 includes a processing unit 51 and a storage unit 53.

[0046] (Processing Unit) The processing unit 51 includes one or more processors such as a CPU and various peripheral components. Part or all of the processing unit 51 may be configured by something updatable such as firmware, or may be a program module or the like executed according to a command from a CPU or the like.

[0047] (Storage Unit) The storage unit 53 is composed of one or more storage elements such as RAM or ROM communicably connected to the processing unit 51. However, the type and number of the storage unit 53 are not particularly limited. The storage unit 53 stores information such as a computer program executed by the processing unit 51, various parameters used for arithmetic processing, detection data, and arithmetic results.

[0048] (2-2. Functional Configuration of Processing Unit) The functional configuration of the processing unit 51 of the control device 50 will be described. The processing unit 51 includes at least an acquisition unit 61, a determination unit 63, a connection control unit 65, and an inverter control unit 67. Each of these units is a function realized by the execution of a computer program by one or more processors such as a CPU. However, part or all of the acquisition unit 61, the determination unit 63, the connection control unit 65, and the inverter control unit 67 may be configured using an analog circuit.

[0049] (Acquisition Unit) The acquisition unit 61 acquires the battery status of the first battery 40a and the second battery 40b, which correspond to the multiple batteries 40. The battery status is the battery voltage detected by the voltage sensor described above, but is not limited to this; it may also be the battery current detected by the current sensor described above, or the State of Charge (SOC) calculated from the battery voltage and battery current.

[0050] The acquisition unit 61 acquires the driving status of the vehicle 1. The driving status is the vehicle speed of the vehicle 1 detected by the vehicle speed sensor, but is not limited to this; it may also be an output value detected by a resolver (not shown) provided in the drive motor 10.

[0051] The acquisition unit 61 may acquire the required torque of the vehicle 1. The required torque may be determined according to the accelerator opening detected by the accelerator position sensor.

[0052] The acquisition unit 61 may acquire the on / off state of the power switch or ignition switch of the vehicle 1.

[0053] (Determination Unit) Based on the battery status of the first battery 40a and the second battery 40b, which correspond to the multiple batteries 40 acquired by the acquisition unit 61, and the driving status of the vehicle 1, the determination unit 63 determines whether to drive the first inverter 20a and the second inverter 20b, which correspond to the multiple inverters 20, from among powering and regenerative braking. Details will be described later.

[0054] Furthermore, the determination unit 63 determines whether or not to independently connect the first battery 40a and the second battery 40b to each of the first inverter 20a and the second inverter 20b, which correspond to the multiple inverters 20, based on the battery status of the first battery 40a and the second battery 40b, which correspond to the multiple batteries 40, acquired by the acquisition unit 61, and the driving status of the vehicle 1. Details will be described later.

[0055] Furthermore, if the required torque of the vehicle 1 acquired by the acquisition unit 61 is less than a predetermined value, the determination unit 63 may decide, based on the battery status of the first battery 40a and the second battery 40b corresponding to the multiple batteries 40, to set either the first inverter 20a or the second inverter 20b corresponding to the multiple inverters 20 to power, and the other to regenerate. If the required torque of the vehicle 1 acquired by the acquisition unit 61 is equal to or greater than a predetermined value, the determination unit 63 may decide to set both the first inverter 20a and the second inverter 20b corresponding to the multiple inverters 20 to power. In this case, the determination unit 63 may decide, based on the battery status of the first battery 40a and the second battery 40b corresponding to the multiple batteries 40, to set the ratio of the drives of the first inverter 20a and the second inverter 20b corresponding to the multiple inverters 20. Details will be described later.

[0056] (Connection Control Unit) The connection control unit 65 controls the connection state between the first inverter 20a and the second inverter 20b, which correspond to the plurality of inverters 20, and the first battery 40a and the second battery 40b, which correspond to the plurality of batteries 40, based on the result of the determination by the determination unit 63. This control can be performed by opening and closing the switching elements SW1, SW2, and SW3.

[0057] (Inverter Control Unit) The inverter control unit 67 controls the driving of the first inverter 20a and the second inverter 20b, which correspond to the plurality of inverters 20, based on the result of the determination by the determination unit 63. Referring also to Figure 2, the inverter control unit 67 may also control the on / off status of the switching elements 24au, 24av, 24aw of the upper arms 22au, 22av, 22aw and the switching elements 26au, 26av, 26aw of the lower arms 23au, 23av, 23aw of the first inverter 20a, based on the result of the determination by the determination unit 63. Furthermore, the inverter control unit 67 may perform on / off control of the switching elements 24bu, 24bv, 24bw of the upper arms 22bu, 22bv, 22bw and the switching elements 26bu, 26bv, 26bw of the lower arms 23bu, 23bv, 23bw of the second inverter 20b based on the result of the determination by the determination unit 63.

[0058] (2-3. Operation Example of the Control Device) Referring to Figure 7, an operation example of the control device 50 according to this embodiment will be explained in accordance with the flowchart. In this operation example, the case in which a plurality of inverters 20 include a first inverter 20a and a second inverter 20b, and a plurality of batteries 40 include a first battery 40a and a second battery 40b will be explained. It will be assumed that the first inverter 20a is connected to the first battery 40a, and the second inverter 20b is connected to the second battery 40b. However, this disclosure is not limited thereto, and the number of batteries, the number of inverters, and the correspondence between each battery and each inverter can be set as appropriate.

[0059] In step S0, the determination unit 63 determines whether the drive system 2 is operating or not. Specifically, the determination unit 63 determines that the drive system 2 is operating if the power switch or ignition switch acquired by the acquisition unit 61 is in the ON state. If it is determined that the drive system 2 is operating (step S0: YES), the process proceeds to step S10. On the other hand, if it is determined that the drive system 2 is not operating (step S0: NO), the process terminates.

[0060] In step S10, the acquisition unit 61 acquires the driving status of the vehicle 1. Specifically, the acquisition unit 61 acquires the vehicle speed of the vehicle 1 from the vehicle status sensor 81. The process then proceeds to step S20. The acquisition unit 61 may also acquire the output value of the resolver provided in the drive motor 10 as the driving status of the vehicle 1.

[0061] In step S20, the determination unit 63 determines whether or not to set the connection state of the first battery 40a and the second battery 40b to the first connection state, based on the driving state of the vehicle 1 acquired in step S10. Specifically, if the vehicle speed of the vehicle 1 is above a threshold, the determination unit 63 decides to set the connection state of the first battery 40a and the second battery 40b to the first connection state. On the other hand, if the vehicle speed of the vehicle 1 is below a threshold, the determination unit 63 decides not to set the connection state of the first battery 40a and the second battery 40b to the first connection state. If it is determined that the connection state of the first battery 40a and the second battery 40b should be set to the first connection state (step S20: YES), the process proceeds to step S30. On the other hand, if it is determined that the connection state of the first battery 40a and the second battery 40b should not be set to the first connection state (step S20: NO), the process proceeds to step S40. The threshold may be the legal speed limit on an expressway, but this disclosure is not limited to this, and can be set as appropriate.

[0062] In step S30, the connection control unit 65 appropriately controls the opening and closing of the switching elements SW1, SW2, and SW3 so that the connection state of the first battery 40a and the second battery 40b becomes the first connection state. As a result, as shown in Figure 3, the first battery 40a and the second battery 40b are connected in series to the first inverter 20a connected to the first stator 11 and the second inverter 20b connected to the second stator 12. After that, the process returns to step S0. Alternatively, the process may return to step S10 instead of returning to step S0. In this case, the process may terminate upon receiving a control signal indicating that the drive system 2 has changed from the ON state to the OFF state.

[0063] In the first connection state of step S30, the inverter control unit 67 performs the following control. Specifically, during powering, the inverter control unit 67 controls the first inverter 20a to convert the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the first stator 11. Similarly, during powering, the inverter control unit 67 controls the second inverter 20b to convert the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the second stator 12. The three-phase AC power supplied to the first stator 11 and the second stator 12 forms a rotating magnetic field, causing the rotor 13 to rotate and outputting drive torque. On the other hand, during regeneration, the inverter control unit 67 controls the first inverter 20a to ensure that no three-phase AC power is supplied to the first stator 11. In this state, the inverter control unit 67 converts the three-phase AC power (regenerative power) generated in the first stator 11 by the rotation of the rotor 13 in response to the rotational torque of the front wheels into DC power by controlling the first inverter 20a, and supplies this DC power to the first battery 40a and the second battery 40b. Similarly, during regeneration, the inverter control unit 67 controls the second inverter 20b to ensure that no three-phase AC power is supplied to the second stator 12. In this state, the inverter control unit 67 converts the three-phase AC power (regenerative power) generated in the second stator 12 by the rotation of the rotor 13 in response to the rotational torque of the front wheels into DC power by controlling the second inverter 20b, and supplies this DC power to the first battery 40a and the second battery 40b. At this time, the current ratio distributed to the first inverter 20a and the second inverter 20b is substantially 1:1.

[0064] In step S40, the acquisition unit 61 acquires the battery states of the first battery 40a and the second battery 40b. Specifically, the acquisition unit 61 acquires the battery voltage from voltage sensors (not shown) provided in each of the first battery 40a and the second battery 40b. The process then proceeds to step S50. In addition to the battery voltage, the acquisition unit 61 may also acquire the battery current from current sensors (not shown) provided in each of the first battery 40a and the second battery 40b. In this case, in step S50, which will be described later, the State of Charge (SOC) that can be calculated from the battery voltage and battery current may be used instead of the battery voltage.

[0065] In step S50, the determination unit 63 determines whether to set the connection state of the first battery 40a and the second battery 40b to the second connection state, based on the battery states of the first battery 40a and the second battery 40b acquired in step S40. Specifically, if the variation in battery voltage between the first battery 40a and the second battery 40b is greater than or equal to a threshold, the determination unit 63 decides to set the connection state of the first battery 40a and the second battery 40b to the second connection state. On the other hand, if the variation in battery voltage between the first battery 40a and the second battery 40b is less than a threshold, the determination unit 63 decides not to set the connection state of the first battery 40a and the second battery 40b to the second connection state. If it is determined that the connection state of the first battery 40a and the second battery 40b is set to the second connection state (step S50: YES), the process proceeds to step S60. On the other hand, if it is determined that the connection state of the first battery 40a and the second battery 40b will not be the second connection state (step S50: NO), the process proceeds to step S80. Note that "battery voltage variation" refers to the degree of deviation of the battery voltages of the multiple batteries 40 from a standard value or statistical value such as the average value. Furthermore, this threshold can be set appropriately so that there is no problem even if the multiple batteries 40 are connected in parallel.

[0066] In step S60, the connection control unit 65 appropriately controls the opening and closing of the switching elements SW1, SW2, and SW3 so that the connection state of the first battery 40a and the second battery 40b becomes the second connection state. As a result, as shown in Figure 4, the first battery 40a is independently connected to the first inverter 20a connected to the first stator 11. On the other hand, the second battery 40b is independently connected to the second inverter 20b connected to the second stator 12. That is, the electrical circuit including the first battery 40a, the first inverter 20a, and the first stator 11 becomes electrically independent from the electrical circuit including the second battery 40b, the second inverter 20b, and the second stator 12. The process then proceeds to step S70.

[0067] In step S70, the processing unit 51 performs SOC adjustment processing between the first battery 40a and the second battery 40b. The SOC adjustment processing in step 70 will be described in detail below with reference to Figure 8.

[0068] In step S71, the acquisition unit 61 acquires the requested torque of the vehicle 1. Specifically, the acquisition unit 61 acquires the accelerator opening from the accelerator position sensor included in the vehicle state sensor 81. Then, the acquisition unit 61 acquires the requested torque of the vehicle 1 driver, which is determined according to the acquired accelerator opening. After that, the process proceeds to step S72.

[0069] In step S72, the determination unit 63 determines whether the requested torque of the vehicle 1 obtained in step S72 is equal to or greater than a predetermined value. If the requested torque of the vehicle 1 is equal to or greater than the predetermined value (step S72: YES), the process proceeds to step S73. On the other hand, if the requested torque of the vehicle 1 is less than the predetermined value (step S72: NO), the process proceeds to step S75. The predetermined value is, for example, half of the peak torque of the motor itself, but this disclosure is not limited thereto and can be set as appropriate.

[0070] In step S73, the determination unit 63 decides to set both the first inverter 20a and the second inverter 20b to power mode. The process then proceeds to step S74.

[0071] In step S74, the inverter control unit 67 controls the first inverter 20a and the second inverter 20b so that both the first inverter 20a and the second inverter 20b are driven in a motoring state. Specifically, the inverter control unit 67 controls the on / off state of the switching elements 24au, 24av, 24aw of the upper arms 22au, 22av, 22aw and the switching elements 26au, 26av, 26aw of the lower arms 23au, 23av, 23aw of the first inverter 20a. As a result, the inverter control unit 67 converts the DC power swept from the first battery 40a into three-phase AC power and supplies this three-phase AC power to the first stator 11. In conjunction with this, the inverter control unit 67 controls the on / off state of the switching elements 24bu, 24bv, 24bw of the upper arms 22bu, 22bv, 22bw of the second inverter 20b and the switching elements 26bu, 26bv, 26bw of the lower arms 23bu, 23bv, 23bw. As a result, the inverter control unit 67 converts the DC power swept from the second battery 40b into three-phase AC power and supplies this three-phase AC power to the second stator 12. The rotor 13 rotates due to the rotating magnetic field formed by the supply of three-phase AC power to both the first stator 11 and the second stator 12, and a drive torque is output.

[0072] At this time, the inverter control unit 67 controls the driving ratio of the first inverter 20a and the second inverter 20b based on the battery states of the first battery 40a and the second battery 40b. Here, we will explain assuming that the state of charge (SOC) of the first battery 40a is higher than the state of charge (SOC) of the second battery 40b. In this case, also referring to Figure 9, the inverter control unit 67 controls the DC power swept from the first battery 40a to the first inverter 20a and the DC power swept from the second battery 40b to the second inverter 20b so that the power P1 supplied from the first battery 40a to the drive motor 10 is greater than the power P2 supplied from the second battery 40b to the drive motor 10.

[0073] Here, assuming that the State of Cost (SOC) of the first battery 40a is higher than that of the second battery 40b, the method for controlling the drive ratio of the first inverter 20a and the second inverter 20b will be described in detail.

[0074] One first control method is to fix the ratio of the drive torque provided by the second inverter 20b to the drive torque provided by the first inverter 20a to a predetermined value. That is, the inverter control unit 67 adjusts the drive ratio of the first inverter 20a and the second inverter 20b so that the ratio of the drive torque provided by the second inverter 20b to the drive torque provided by the first inverter 20a becomes a predetermined value. This predetermined value can be appropriately selected from, for example, a range of 10% to 50%.

[0075] A second control method is to fix the target current amount I. The inverter control unit 67 calculates the drive ratio α1 of the first inverter 20a using the following equation (1). The inverter control unit 67 also calculates the drive ratio α2 of the second inverter 20b using the following equation (2). Here, I is the target current value of each battery, V is the battery voltage value of each battery, T is the torque, N is the rotational speed, T × N is the target energy amount (W = T × N), and I × V is a predetermined value in step S72. Here, I and V may take different values ​​for each battery, but when the target current amount I is fixed, the product of the voltage V1 and current I1 of the first battery 40a and the product of the battery voltage V2 and current I2 of the second battery 40b will be the same or substantially the same.

[0076]

[0077]

[0078] In this case, the ratio α1 may be calculated recursively to satisfy equation (3) below. In this case, the ratio α2 is calculated to satisfy equation (4) below. Note that p in equation (3) below is the motor inverter efficiency, and is a function that takes torque T and rotational speed N (and possibly motor temperature) as arguments, which can be calculated by equation (5) below.

[0079]

[0080]

[0081]

[0082] A third control method involves controlling the driving ratio of the first inverter 20a and the second inverter 20b so that the SOC of the first battery 40a and the SOC of the second battery 40b become equal after a predetermined time has elapsed. Specifically, the inverter control unit 67 calculates the adjustment charge amount Q necessary to eliminate the SOC difference based on the SOC difference between the first battery 40a and the second battery 40b using the Coulomb counting method or the like. The inverter control unit 67 then calculates the current amount I (= Q / t) such that the SOC difference is eliminated after a predetermined time t seconds. The inverter control unit 67 then determines the driving ratio of the first inverter 20a and the second inverter 20b based on the calculated current amount I, similar to the second control method. The predetermined value in step S72 is I × V, using the target current amount I and the battery voltage V.

[0083] However, in all of the first to third control methods, the drive torque obtained by the total power P (= P1 + P2) of power P1 and power P2 must be matched to the required torque. The first control method minimizes the amount of computation, but it is not easy to predict the time until SOC adjustment is complete. In contrast, the second control method makes it easy to predict the time until SOC adjustment is complete. Furthermore, the third control method makes it easy to adjust the time until SOC adjustment is complete. For example, the third control method is particularly effective when SOC adjustment needs to be performed quickly and within a specified time, such as when a high torque output is required within a few minutes (e.g., within 5 minutes). Note that if the SOC of the second battery 40b is higher than the SOC of the first battery 40a, the relationship between powers P1 and P2 is controlled to be the opposite of what is described above.

[0084] On the other hand, if the process proceeds from step S72 to step S75, in step S75, the determination unit 63 determines, based on the battery states of the first battery 40a and the second battery 40b, that either the first inverter 20a or the second inverter 20b will be driven for power, and the other for regeneration. Specifically, if the SOC of the first battery 40a is higher than the SOC of the second battery 40b, the determination unit 63 determines that the first inverter 20a will be driven for power, and the second inverter 20b will be driven for regeneration. On the other hand, if the SOC of the second battery 40b is higher than the SOC of the first battery 40a, the determination unit 63 determines that the first inverter 20a will be driven for regeneration, and the second inverter 20b will be driven for power. After that, the process proceeds to step S76.

[0085] In step S76, the inverter control unit 67 controls the first inverter 20a and the second inverter 20b so that either the drive of the first inverter 20a or the drive of the second inverter 20b becomes power generation and the other becomes regenerative braking.

[0086] Here, we will describe the case where the first inverter 20a is used for power driving and the second inverter 20b is used for regenerative driving. Specifically, referring to Figure 10, the inverter control unit 67 controls the on / off state of the switching elements 24au, 24av, 24aw of the upper arms 22au, 22av, 22aw and the switching elements 26au, 26av, 26aw of the lower arms 23au, 23av, 23aw of the first inverter 20a. As a result, the inverter control unit 67 converts the DC power swept from the first battery 40a into three-phase AC power and supplies this three-phase AC power to the first stator 11. In conjunction with this, the inverter control unit 67 controls the on / off state of the switching elements 24bu, 24bv, 24bw of the upper arms 22bu, 22bv, 22bw of the second inverter 20b and the switching elements 26bu, 26bv, 26bw of the lower arms 23bu, 23bv, 23bw. As a result, the inverter control unit 67 keeps the second stator 12 in a state where no three-phase AC power is supplied. Then, when the rotor 13 rotates due to the rotating magnetic field formed by the supply of three-phase AC power to the first stator 11 in response to the output from the first inverter 20a, a portion of the output obtained from the rotation of the rotor 13 is output as driving torque, while the remainder is supplied to the second battery 40b as regenerative power. Therefore, the second battery 40b is charged using power P2 of the power P1 from the first inverter 20a. In other words, the drive torque output from the drive motor 10 is a torque equivalent to the power P (= P1 - P2) obtained by subtracting the power P2 used to charge the second battery 40b from the power P1. The distribution between the power P (= P1 - P2) equivalent to the drive torque and the regenerated power (= P2) can be set by the inverter control unit 67 controlling the on / off timing of the switching elements 24au, 24av, 24aw, 26au, 26av, 26aw of the first inverter 20a and the on / off timing of the switching elements 24bu, 24bv, 24bw, 26bu, 26bv, 26bw of the second inverter 20b. Specifically, the inverter control unit 67 adjusts the three-phase currents of the first inverter 20a and the second inverter 20b so that a three-phase current equivalent to the required torque of the vehicle 1 obtained in step S72 flows.

[0087] On the other hand, let's describe the case where the first inverter 20a is driven by regeneration and the second inverter 20b is driven by power. In this case, the inverter control unit 67 controls the on / off state of the switching elements 24bu, 24bv, 24bw of the upper arms 22bu, 22bv, 22bw and the switching elements 26bu, 26bv, 26bw of the lower arms 23bu, 23bv, 23bw of the second inverter 20b. As a result, the inverter control unit 67 converts the DC power swept from the second battery 40b into three-phase AC power and supplies this three-phase AC power to the second stator 12. In conjunction with this, the inverter control unit 67 controls the on / off state of the switching elements 24au, 24av, 24aw on the upper arms 22au, 22av, 22aw and the switching elements 26au, 26av, 26aw on the lower arms 23au, 23av, 23aw of the first inverter 20a. As a result, the inverter control unit 67 keeps the first stator 11 in a state where no three-phase AC power is supplied. Then, when the rotor 13 rotates due to the rotating magnetic field formed by the supply of three-phase AC power to the second stator 12 in response to the output from the second inverter 20b, a portion of the output obtained from the rotation of the rotor 13 is output as driving torque, and the remainder is supplied to the first battery 40a as regenerative power. Therefore, the first battery 40a is charged using power P1 of the power P2 from the second inverter 20b. In other words, the drive torque output from the drive motor 10 is the torque equivalent to the power P obtained by subtracting the power P1 used to charge the first battery 40a from the power P2 (= P2 - P1). The details are as described above. The torque equivalent to power P is calculated by the inverter control unit 67 to satisfy the required torque of the vehicle 1 obtained in step S72.

[0088] As described above, the processing unit 51 performs SOC adjustment processing between the first battery 40a and the second battery 40b. In performing SOC adjustment processing, the processing unit 51 determines the drive of the first inverter 20a and the second inverter 20b from among powering and regeneration based on the battery state of the first battery 40a and the second battery 40b and the driving state of the vehicle 1. After that, the process returns to step S40 shown in Figure 7.

[0089] During the SOC adjustment process, the acquisition unit 61 may acquire the vehicle speed of vehicle 1 at predetermined time intervals in the same manner as in step S10. The determination unit 63 may then determine, in the same manner as in step S20, that the vehicle speed of vehicle 1 is equal to or greater than a threshold, and decide to terminate the SOC adjustment process and set the connection state of the first battery 40a and the second battery 40b to the first connection state. The connection control unit 65 may then appropriately control the opening and closing of the switching elements SW1, SW2, and SW3 in the same manner as in step S30 so that the connection state of the first battery 40a and the second battery 40b becomes the first connection state. The subsequent process is as described above.

[0090] Returning to Figure 7, if the process progresses from step S50 to step S80, in step S80, the connection control unit 65 appropriately controls the opening and closing of switching elements SW1, SW2, and SW3 so that the connection state of the first battery 40a and the second battery 40b becomes the third connection state. As a result, as shown in Figure 5, the first battery 40a and the second battery 40b are connected in parallel to the first inverter 20a connected to the first stator 11 and the second inverter 20b connected to the second stator 12. The first inverter 20a and the second inverter 20b are connected in parallel to each other. After that, the process returns to step S0. Alternatively, the process may return to step S10 instead of returning to step S0. In this case, the process may terminate upon receiving a control signal indicating that the drive system 2 has changed from the ON state to the OFF state.

[0091] In the third connection state of step S80, the inverter control unit 67 performs the following control. Specifically, during powering, the inverter control unit 67 controls the first inverter 20a to convert the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the first stator 11. Similarly, during powering, the inverter control unit 67 controls the second inverter 20b to convert the DC power swept from the first battery 40a and the second battery 40b into three-phase AC power and supplies this three-phase AC power to the second stator 12. The three-phase AC power supplied to the first stator 11 and the second stator 12 forms a rotating magnetic field, causing the rotor 13 to rotate and outputting drive torque. On the other hand, during regeneration, the inverter control unit 67 controls the first inverter 20a to ensure that no three-phase AC power is supplied to the first stator 11. In this state, the inverter control unit 67 converts the three-phase AC power (regenerative power) generated in the first stator 11 by the rotation of the rotor 13 in response to the rotational torque of the front wheels into DC power by controlling the first inverter 20a, and supplies this DC power to the first battery 40a and the second battery 40b. Similarly, during regeneration, the inverter control unit 67 controls the second inverter 20b to ensure that no three-phase AC power is supplied to the second stator 12. In this state, the inverter control unit 67 converts the three-phase AC power (regenerative power) generated in the second stator 12 by the rotation of the rotor 13 in response to the rotational torque of the front wheels into DC power by controlling the second inverter 20b, and supplies this DC power to the first battery 40a and the second battery 40b. Here, the power ratio output from the first battery 40a and the second battery 40b is substantially 1:1. However, if there is a difference in internal resistance between the first battery 40a and the second battery 40b due to deterioration or temperature, a difference corresponding to the internal resistance may occur in the power ratio. Also, the amount of power distributed to the first inverter 20a and the second inverter 20b depends on the power supplied by the first inverter 20a and the second inverter 20b to the drive motor 10, respectively.When a first inverter 20a and a second inverter 20b are connected to a drive motor 10 having the same rotational speed, the amount of power depends on the required torque for each of the first inverter 20a and the second inverter 20b.

[0092] (Effects) As described above, the processing unit 51 of the control device 50 according to this embodiment controls the drive system 2 of a vehicle 1, which comprises a first battery 40a and a second battery 40b, a drive motor 10 having one output shaft, two sets of three-phase windings arranged around one output shaft, and a first inverter 20a and a second inverter 20b connected to the two sets of three-phase windings, respectively. Specifically, the processing unit 51 of the control device 50 acquires the driving state of the vehicle 1. The processing unit 51 also acquires the battery state of the first battery 40a and the second battery 40b. Then, based on the acquired battery state of the first battery 40a and the second battery 40b and the driving state of the vehicle 1, the processing unit 51 determines whether to drive the first inverter 20a and the second inverter 20b from among powering and regenerative braking.

[0093] Specifically, if the required torque of the vehicle 1 is less than a predetermined value, the processing unit 51 of the control device 50 sets the connection of the first battery 40a and the second battery 40b to the first inverter 20a and the second inverter 20b to independent connection (second connection state). Then, based on the battery state of the first battery 40a and the second battery 40b, the processing unit 51 decides to set either the drive of the first inverter 20a or the drive of the second inverter 20b to power, and the other to regenerative braking. On the other hand, if the required torque of the vehicle 1 is equal to or greater than a predetermined value, the processing unit 51 sets the connection of the first battery 40a and the second battery 40b to independent connection. Then, the processing unit 51 decides to set both the drive of the first inverter 20a and the second inverter 20b to power. The processing unit 51 then controls the driving ratio of the first inverter 20a and the second inverter 20b based on the battery status of the first battery 40a and the second battery 40b.

[0094] With this configuration, the first battery 40a and the second battery 40b are independently connected to the first inverter 20a and the second inverter 20b, respectively, so that energy (power) is transferred through a single output shaft. As a result, the SOC (State of Control) between the multiple batteries 40 mounted on the vehicle 1 can be adjusted quickly. This makes it possible to utilize the characteristics of the first battery 40a and the second battery 40b when they are connected in series and the characteristics of the first battery 40a and the second battery 40b when they are connected in parallel.

[0095] Preferred embodiments of the present disclosure have been described in detail above with reference to the attached drawings, but the present disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art to which the present disclosure belongs that various modifications or alterations can be conceived within the scope of the technical idea described in the claims, and these will naturally also be understood to fall within the technical scope of the present disclosure. For example, the functions etc. included in each component or each step etc. can be rearranged in a logically consistent manner, and multiple components or steps etc. can be combined into one or divided into two.

[0096] (First Modification) In the embodiments described above, the drive motor 10 is a motor having one output shaft (rotor shaft) and is configured as a motor including at least two sets of multiphase windings arranged around one output shaft (rotor shaft). However, the disclosure is not limited thereto, and the drive motor may include two or more motors, and one output shaft may be formed by connecting the rotor shafts of each motor to each other. In this case, each motor includes a set of multiphase windings arranged around its rotor shaft. Now, the case in which the drive motor includes a first motor and a second motor will be described. The first motor includes a first stator connected to a first inverter connected to a first multiphase winding, and a first rotor. On the other hand, the second motor includes a second stator connected to a second inverter connected to a second multiphase winding, and a second rotor. The rotor shaft of the first rotor and the rotor shaft of the second rotor are connected to each other. Furthermore, the rotor shaft of the first rotor and the rotor shaft of the second rotor only need to be mechanically fastened together, and may be connected, for example, via gears. Other aspects are the same as in the embodiment described above.

[0097] (Second Modification) In the embodiment described above, the case in which the plurality of batteries 40 include a first battery 40a and a second battery 40b was described. However, the disclosure is not limited thereto, and the plurality of batteries 40 may include three or more batteries. In this case, each of the plurality of inverters 20 is configured to correspond to each battery. In particular, in step S76 described above, the drive of the inverter connected to the battery with an SOC higher than the reference value may be defined as powering, and the drive of the inverter connected to the battery with an SOC lower than the reference value may be defined as regeneration. The reference value is the average value of the SOC of all batteries, etc. However, the disclosure is not limited thereto, and the number of batteries corresponding to powering or regeneration may be changed according to the required torque obtained in step S71.

[0098] Furthermore, the technology disclosed herein can also be realized as a vehicle 1 equipped with the control device 50 described in the above-described embodiment, a control method executed by the control device 50, a control program that causes a computer to function as the control device 50 described above, and a non-temporary tangible recording medium that records the control program.

[0099] 1: Vehicle, 2: Drive system, 10: Drive motor, 11: First stator, 12: Second rotor, 13: Rotor, 20: Inverter, 20a: First inverter, 20b: Second inverter, 40: Battery, 40a: First battery, 40b: Second battery, 50: Control device, 51: Processing unit, 53: Memory unit, 61: Acquisition unit, 63: Determination unit, 65: Connection control unit, 67: Inverter control unit

Claims

1. A control device for controlling a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, the control device comprising: one or more processors; and one or more memories communicately connected to the one or more processors, wherein the one or more processors acquire the battery state of the plurality of batteries; acquire the running state of the vehicle; and determine the drive of each of the plurality of inverters from among powering and regenerating based on the acquired battery state of the plurality of batteries and the running state of the vehicle.

2. The control device according to claim 1, wherein one or more processors determine whether or not to independently connect each of the plurality of batteries to each of the plurality of inverters based on the battery state of the plurality of batteries and the driving state of the vehicle.

3. The control device according to claim 2, wherein the plurality of batteries include a first battery and a second battery, the plurality of inverters include a first inverter and a second inverter, the first inverter is connected to the first battery, the second inverter is connected to the second battery, and one or more processors acquire the required torque of the vehicle, and if the acquired required torque is less than a predetermined value, determines, based on the battery state of the first battery and the second battery, to set either the drive of the first inverter or the drive of the second inverter to power, and the other to regenerate.

4. The control device according to claim 2, wherein one or more processors acquire the required torque of the vehicle, and if the acquired required torque is equal to or greater than a predetermined value, decide to set all of the plurality of inverters to power, and control the ratio of the drives of each inverter based on the battery state of the plurality of batteries.

5. A control method for controlling a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, the control method comprising: a computer acquiring the battery state of the plurality of batteries; acquiring the running state of the vehicle; and determining the drive of each of the plurality of inverters from among powering and regenerating based on the acquired battery state of the plurality of batteries and the running state of the vehicle.

6. A non-temporary tangible recording medium that records a control program for controlling a vehicle drive system comprising: a plurality of batteries; at least one motor having one output shaft; at least two sets of polyphase windings arranged around the one output shaft; and a plurality of inverters each connected to the at least two sets of polyphase windings, wherein the recording medium records a control program that causes a computer to: acquire the battery status of the plurality of batteries; acquire the running status of the vehicle; and determine whether to drive each of the plurality of inverters from powering and regenerating based on the acquired battery status of the plurality of batteries and the running status of the vehicle.

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