Vehicle control device, vehicle control method, and vehicle control program

Abstract

A vehicle control device comprises: an inverter control unit for controlling an inverter (151) that drives a vehicle-driving rotary electric machine (100) mounted on a vehicle (100); and control units (44, 46) that executes control to suppress the torque of the rotary electric machine so as to lower the temperature of a drive unit (152) including the rotary electric machine and the inverter when a lock state in which the rotary electric machine does not rotate is detected during energization of the rotary electric machine, and when it is assumed there will be an increase in the temperature of the drive unit (152).

Description

Vehicle control device, vehicle control method, and vehicle control program CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of priority from Patent Application No. 2023-201891, filed November 29, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a vehicle control device, a vehicle control method, and a vehicle control program.

[0003] Patent Document 1 discloses a control device that detects the rotation angle of a rotating electric machine and changes the detected rotation angle to reduce the load on the rotating electric machine. The control device in Patent Document 1 changes the rotation angle detected by a sensor.

[0004] JP 2019-85001 A

[0005] As a result of detailed investigations by the inventors, when a rotating electric machine stops rotating despite torque being applied to the rotating electric machine, a single-phase continuous current state may occur, in which current continues to flow through a specific phase among the multiple phases of the rotating electric machine. In this case, the thermal load of the specific phase may increase several times compared to when there is no overload. Even if the rotation angle of the rotating electric machine is changed as in the conventional technology of Patent Document 1, current may continue to flow through the specific phase again. Furthermore, for example, when a vehicle goes over a bump, if the load torque acting on the rotating electric machine and the torque generated by the rotating electric machine (acceleration demand value) are balanced, the vehicle may come to a standstill. In this case, the inventors discovered a problem in that the single-phase continuous current state may continue without changing the rotation angle of the rotating electric machine. As such, the conventional technology has room for improvement in terms of reducing the temperature of the rotating electric machine and the like.

[0006] The present disclosure aims to provide a vehicle control device, a vehicle control method, and a vehicle control program that are capable of appropriately performing control to lower the temperature of a rotating electric machine or the like.

[0007] A vehicle control device according to a first aspect of the present disclosure includes an inverter control unit that controls an inverter that drives a rotating electric machine mounted on a vehicle for driving the vehicle, and a control unit that, when detecting a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine, executes control to suppress the torque of the rotating electric machine so as to lower the temperature when a temperature rise in a drive unit including the rotating electric machine and the inverter is expected.

[0008] A vehicle control program according to a second aspect of the present disclosure causes at least one processor to execute processing including controlling an inverter that drives a rotating electric machine mounted on a vehicle for driving the vehicle, and when a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine is detected, executing control to suppress the torque of the rotating electric machine so as to lower the temperature when a temperature rise in a drive unit including the rotating electric machine and the inverter is expected.

[0009] A vehicle control method according to a third aspect of the present disclosure includes a process in which at least one processor controls an inverter that drives a rotating electric machine mounted on a vehicle for driving the vehicle, and when a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine is detected, the process includes performing control to suppress the torque of the rotating electric machine so as to lower the temperature when a temperature rise in a drive unit including the rotating electric machine and the inverter is expected.

[0010] According to the present disclosure, a vehicle control device, a vehicle control method, and a vehicle control program are provided that are capable of appropriately performing control to lower the temperature of a rotating electric machine or the like.

[0011] FIG. 1 is a schematic diagram showing an example of the configuration of a vehicle. FIG. 2 is a block diagram showing an example of the hardware configuration of a vehicle control device. FIG. 3 is a block diagram showing an example of a sensor group. FIG. 4 is a block diagram showing an example of the functional configuration of a CPU. FIG. 5 is a block diagram showing an example of a functional unit constituting a protection control unit in further detail. FIG. 6 is a circuit configuration diagram showing an example of a drive unit. FIG. 7 is a flowchart showing an example of protection control processing. FIG. 8 is a flowchart showing an example of bump climbing control processing. FIG. 9 is a flowchart showing an example of torque selection processing. FIG. 10 is a flowchart showing an example of temperature estimation processing. FIG. 11 is a timing chart showing an example of operation of the temperature estimation processing. FIG. 12 is a flowchart showing a modified example of the temperature estimation processing. FIG. 13 is a flowchart showing an example of single-phase continuous current determination processing. FIG. 14 is a flowchart showing an example of overheat protection determination processing. FIG. 15 is a flowchart showing an example of overheat protection control processing. FIG. 16 is a flowchart showing an example of overheat protection control processing. FIG. 17 is a timing chart for explaining the overheat protection control processing. FIG. 18 is a flowchart showing an overheat protection control processing according to a modified example. FIG. 19 is a flowchart showing an overheat protection control processing according to a modified example. FIG. 20 is a timing chart for explaining the overheat protection control processing according to a modified example. FIG. 21 is a diagram for explaining speed feedback control. FIG. 22 is a flowchart for explaining speed feedback control. FIG. 23 is a timing chart for explaining speed feedback control. FIG. 24 is a flowchart for explaining an example of accelerator hill-hold countermeasure processing. FIG. 25 is a first flowchart showing an example of permission determination processing. FIG. 26 is a second flowchart showing an example of permission determination processing. FIG. 27 is a graph showing an example of determination threshold map data. FIG. 28 is a flowchart for explaining step estimation processing. FIG. 29 is a side view showing an example of a state in which a wheel has come into contact with a step. FIG. 30 is a graph showing an example of the trajectory and trajectory angle of the wheel rotation center axis. FIG. 31 is a flowchart for explaining one-wheel and two-wheel climb-up determination processing. FIG. 32 is a flowchart for explaining an example of misstep determination processing. FIG. 33 is a flowchart for explaining climb-up prohibition control.FIG. 34 is a diagram showing an example of the relationship between vehicle speed, step height, and step climbing control.

[0012] Hereinafter, the present embodiment will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicated descriptions will be omitted.

[0013] A vehicle control device 10 according to this embodiment is mounted on a vehicle 100 and configured as a device for controlling the vehicle 100. Prior to describing the vehicle control device 10, the configuration of the vehicle 100 will first be described with reference to FIG.

[0014] The vehicle 100 is a vehicle that travels based on the driving operation of a driver. However, when a wheel comes into contact with a bump, part of the driving operation (e.g., braking) may be automatically performed by the vehicle control device 10. The vehicle 100 includes a vehicle body 101, wheels 111, 112, 121, and 122, a rotating electric machine 150, and a battery 160.

[0015] The vehicle body 101 is the main body of the vehicle 100 and is referred to as the "body." The wheel 111 is a wheel provided on the front left part of the vehicle body 101, and the wheel 112 is a wheel provided on the front right part of the vehicle body 101. The wheels 111 and 112, which are front wheels, are provided as driven wheels in this embodiment.

[0016] Wheel 121 is a wheel provided on the rear left side of vehicle body 101, and wheel 122 is a wheel provided on the rear right side of vehicle body 101. In this embodiment, rear wheels 121 and 122 are provided as drive wheels. That is, wheels 121 and 122 rotate by the driving force of a rotating electric machine 150 (described later) to propel vehicle 100.

[0017] In this way, the vehicle 100 of this embodiment is configured as a so-called "rear-wheel drive" vehicle. Alternatively, the vehicle 100 may be configured as a front-wheel drive vehicle or a four-wheel drive vehicle. In the latter case, in addition to the rotating electric machine 150 for driving the rear wheels, a rotating electric machine 150 for driving the front wheels may be separately provided.

[0018] A brake device 131 is provided on the wheel 121, and a brake device 132 is provided on the wheel 122. Both brake devices 131 and 132 are braking devices that apply braking force to the wheels by hydraulic pressure. Such braking devices may be provided not only on the driving wheels but also on the wheels 111 and 112, which are driven wheels. The operation of the brake devices 131 and 132 is controlled by a brake ECU 20, which will be described later.

[0019] The rotating electric machine 150 is a device that receives a supply of electric power from a battery 160 (described later) and generates a driving force for rotating the wheels 121, 122, i.e., a driving force required for the vehicle 100 to travel. The rotating electric machine 150 is, for example, a so-called "motor generator." The driving force generated by the rotating electric machine 150 is transmitted to each of the wheels 121, 122 via the powertrain unit 140, causing the wheels 121, 122 to rotate. Note that the exchange of electric power between the battery 160 and the rotating electric machine 150 is performed via an inverter (described later), but this inverter is not shown in FIG. 1 .

[0020] The rotating electric machine 150 generates a driving force for accelerating the vehicle 100, and can also generate a braking force by regeneration to decelerate the vehicle 100. The braking of the vehicle 100 can be performed by the rotating electric machine 150, or by the brake devices 131 and 132 described above.

[0021] The battery 160 is a storage battery for supplying driving power to the rotating electric machine 150. In this embodiment, as an example, a lithium ion battery is used as the battery 160. Regenerative power generated by the rotating electric machine 150 during braking is supplied to the battery 160 via an inverter and charged into the battery 160.

[0022] The vehicle 100 is provided with a brake ECU 20 separate from the vehicle control device 10. Both the vehicle control device 10 and the brake ECU 20 are configured as computer systems having a CPU, ROM, RAM, etc. These can communicate with each other bidirectionally via a network provided in the vehicle 100. Details of the hardware configuration of the vehicle control device 10 will be described later.

[0023] The brake ECU 20 performs processing to control the operation of the brake devices 131 and 132 in response to instructions from the vehicle control device 10 .

[0024] The vehicle control device 10 and the brake ECU 20 do not have to be separated into two devices as in the present embodiment. For example, the functions of the brake ECU 20 may be integrated into the vehicle control device 10. When realizing the functions of the vehicle control device 10 described later, the specific device configuration is not particularly limited.

[0025] Fig. 2 is a block diagram showing the hardware configuration of the vehicle control device 10. As shown in Fig. 2, the vehicle control device 10 includes a control unit 21. The control unit 21 is configured as a device including a general computer.

[0026] The control unit 21 includes a central processing unit (CPU) 21A, a read-only memory (ROM) 21B, a random access memory (RAM) 21C, and an input / output interface (I / O) 21D. The CPU 21A, ROM 21B, RAM 21C, and I / O 21D are connected to each other via a bus 21E. The bus 21E includes a control bus, an address bus, a data bus, and the like.

[0027] The I / O 21D is connected to a communication unit 22, a storage unit 23, and a sensor group 200.

[0028] The communication unit 22 is an interface for communicating with external devices such as the brake ECU 20 and the rotating electrical machine 150 .

[0029] The storage unit 23 is configured as a non-volatile external storage device such as a hard disk, etc. The storage unit 23 stores a vehicle control program 23A, torque map data 23B, judgment threshold map data 23C, gradient torque map data 23D, etc.

[0030] The CPU 21A is an example of a computer. The term "computer" as used herein refers to a processor in a broad sense, and includes a general-purpose processor (e.g., a CPU) or a dedicated processor (e.g., a GPU: Graphics Processing Unit, an ASIC: Application Specific Integrated Circuit, an FPGA: Field Programmable Gate Array, a programmable logic device, etc.).

[0031] The vehicle control program 23A may be stored in a non-volatile, non-transitory recording medium or distributed via a network and appropriately installed in the vehicle control device 10, thereby being stored in the storage unit 23. The vehicle control program 23A may also be appropriately updated via so-called OTA (Over The Air).

[0032] Examples of non-volatile non-transient recording media include CD-ROMs (Compact Disc Read Only Memory), magneto-optical disks, HDDs (Hard Disk Drives), DVD-ROMs (Digital Versatile Disc Read Only Memory), flash memories, memory cards, etc.

[0033] The vehicle 100 may be provided with a large number of sensors for measuring various physical quantities. As shown in Fig. 3, the sensor group 200 may include a wheel speed sensor 201, an acceleration sensor 202, a current sensor 203, an outside camera 204, an accelerator sensor 205, an external temperature sensor 206, and a gradient sensor 207. The sensor group 200 may also include a brake sensor 208, a parking sensor 209, a yaw rate sensor 210, a rotation speed sensor 211, and a cooling sensor 212.

[0034] The wheel speed sensor 201 is a sensor for measuring the number of rotations per unit time of the wheel 111, etc. Although the wheel speed sensor 201 is provided individually for each of the four wheels 111, 112, 121, and 122, in FIG. 3 , the wheel speed sensor 201 is schematically depicted as a single block. A signal indicating the number of rotations measured by the wheel speed sensor 201 is input to the vehicle control device 10. The vehicle control device 10 can grasp the traveling speed of the vehicle 100 based on this signal.

[0035] The acceleration sensor 202 is a sensor for detecting the acceleration of the vehicle 100. The acceleration sensor 202 is attached to the vehicle body 101. The acceleration sensor 202 is configured as a six-axis acceleration sensor that can detect the accelerations of the vehicle body 101 in the front-rear, left-right, and up-down directions, as well as the rotational accelerations of pitching, rolling, and yawing.

[0036] The acceleration acquired by the acceleration sensor 202 includes an acceleration GX along the traveling direction of the vehicle 100 (i.e., the longitudinal direction) and an acceleration Gy along the lateral direction of the vehicle 100. The acceleration GX is also called "longitudinal acceleration," and the acceleration G is also called "lateral acceleration." Both of these are acquired as numerical values ​​in units of "G," which is the gravitational acceleration, such as "0.5 G." Signals indicating the respective accelerations detected by the acceleration sensor 202 are input to the vehicle control device 10.

[0037] The current sensor 203 is a sensor for detecting the value of the drive current flowing through the rotating electric machine 150. A signal indicating the value of the drive current detected by the current sensor 203 is input to the vehicle control device 10. The vehicle control device 10 can determine the magnitude of the drive force generated by the rotating electric machine 150 based on the value of the input drive current.

[0038] The exterior camera 204 is a camera that captures images of the surroundings of the vehicle 100, and is, for example, a CMOS (Complementary Metal Oxide Semiconductor) camera. Image data captured by the exterior camera 204 is input to the vehicle control device 10. By processing the images, the vehicle control device 10 can determine the presence and shape of obstacles (e.g., steps such as wheel chocks) around the vehicle 100.

[0039] Note that vehicle 100 may be equipped with other sensors in addition to exterior camera 204 or instead of exterior camera 204 as sensors for detecting the conditions around vehicle 100. Examples of such sensors include a LIDAR (Light Detection and Ranging) sensor and radar.

[0040] The accelerator sensor 205 is a sensor that detects the amount of accelerator pedal operation, i.e., the accelerator opening degree. A signal indicating the amount of accelerator pedal operation detected by the accelerator sensor 205 is input to the vehicle control device 10.

[0041] The external temperature sensor 206 is a sensor that detects the temperature outside the vehicle 100. A signal indicating the external temperature detected by the external temperature sensor 206 is input to the vehicle control device 10.

[0042] The gradient sensor 207 is a sensor that detects the gradient of the road surface on which the vehicle 100 is traveling. A signal indicating the gradient detected by the gradient sensor 207 is input to the vehicle control device 10.

[0043] The brake sensor 208 is a sensor that detects the brake hydraulic pressure of the brake devices 131 and 132. A signal indicating the brake hydraulic pressure detected by the brake sensor 208 is input to the vehicle control device 10.

[0044] The parking sensor 209 is a sensor that detects the on / off state of the parking brake of the vehicle 100. A signal indicating the on / off state detected by the parking sensor 209 is input to the vehicle control device 10.

[0045] The yaw rate sensor 210 is a sensor for detecting the yaw rate of the vehicle 100. A signal indicating the yaw rate detected by the yaw rate sensor 210 is input to the vehicle control device 10.

[0046] The rotation speed sensor 211 is a sensor for detecting the rotation angle and rotation speed of the rotating electric machine 150. A signal indicating the rotation speed detected by the rotation speed sensor 211 is input to the vehicle control device 10.

[0047] The cooling sensor 212 is a sensor for detecting the temperature of the cooling water that cools the drive unit 152. The drive unit 152 may include the rotating electric machine 150 and the inverter 151. The cooling water cools the inverter 151, for example. A signal indicating the temperature detected by the cooling sensor 212 is input to the vehicle control device 10.

[0048] 4 is a block diagram showing the functional configuration of the CPU 21A of the vehicle control device 10. As shown in FIG. 4, the CPU 21A functionally includes a protection control unit 30, a bump climbing control unit 32, a torque selection control unit 34, and an inverter control unit 35.

[0049] The protection control unit 30 executes a protection control process to protect the drive unit 152 by suppressing overheating of the rotary electric machine 150 and the drive unit 152 including the inverter 151 .

[0050] The step-over control unit 32 executes step-over control processing for the vehicle 100 to overcome a step.

[0051] The torque selection control unit 34 executes a torque selection control process for selecting and controlling the torque of the rotating electrical machine 150 .

[0052] The inverter control unit 35 controls an inverter 151 that drives a rotating electric machine 150 for driving the vehicle that is mounted on the vehicle.

[0053] The CPU 21A shown in Fig. 2 functions as each functional unit shown in Fig. 4 by reading and executing a vehicle control program 23A stored in the storage unit 23. The vehicle control program 23A executes processes including a protection control process shown in Fig. 7, a step-over control process shown in Fig. 8, and a torque selection process shown in Fig. 9, which will be described later.

[0054] Fig. 5 is a block diagram showing in more detail the functional units that make up the protection control unit 30. As shown in Fig. 5, the protection control unit 30 includes the following functional units: a temperature estimation unit 42, an overheat protection determination unit 44, an overheat protection control unit 46, and a speed feedback control unit 47. The temperature estimation unit 42 executes the temperature estimation process shown in Fig. 10. The overheat protection determination unit 44 executes the overheat protection determination process shown in Fig. 14. The overheat protection control unit 46 executes the overheat protection control process shown in Fig. 18.

[0055] The temperature estimation unit 42 is an example of an "estimation unit" in the present disclosure, and the functional unit including the overheat protection determination unit 44 and the overheat protection control unit 46 is an example of a "control unit" in the present disclosure.

[0056] When the control unit detects a locked state in which the rotating electric machine 150 does not rotate when current is applied to the rotating electric machine 150, and a temperature rise in the drive unit 152 including the rotating electric machine 150 and the inverter 151 is expected, the control unit executes control to suppress the torque of the rotating electric machine 150 so as to lower the temperature. A case in which an increase in the sensitivity of the drive unit including the rotating electric machine and the inverter is expected typically corresponds to a locked state, and a single-phase continuous current state in which current flows continuously in a specific phase of the multiple phases of the rotating motor for a specific period of time or more.

[0057] The control unit detects a locked state based on at least one of the following: when the accelerator operation amount of the vehicle 100 is greater than a specific value; when it detects that the vehicle 100 has stopped based on the vehicle speed of the vehicle 100; when it detects that the road load is excessive based on gradient information of the road surface on which the vehicle 100 is traveling or step load estimation information that indicates the load when the vehicle 100 goes over a step on the road surface; and when it detects a state in which the vehicle 100 has stopped due to a balance between the motor torque and the load torque acting on the rotating electric machine 150 and the motor torque is greater than a specific value.

[0058] When the control unit is in the locked state, and a specific phase among the multiple phases of the rotating electric machine 150 enters a single-phase continuous current state in which current flows continuously for a specific period of time or more, the control unit stores the specific phase as a current-carrying phase in the single-phase continuous current state, and when it detects that the specific phase has entered the single-phase continuous current state again, it forcibly shifts the electrical angle at which current is passed through the specific phase so that the current-carrying phase is not the same as the specific phase.

[0059] When the control unit forcibly shifts the electrical angle at which current is supplied to a specific phase, the control unit changes the electrical angle by a specific amount per specific time period.

[0060] The control unit continues to change the electrical angle until the electrical angle reaches a specific electrical angle obtained by adding a specific value to the stored electrical angle at which current is applied to the specific phase.

[0061] The control unit continues to change the electrical angle until the accelerator pedal of the vehicle 100 is released or until the vehicle 100 goes over a step on the road surface.

[0062] When a temperature rise is expected, the control unit executes current control to continuously switch the current-carrying phases among the multiple phases of the rotating electric machine 150 so that the rotating electric machine 150 continues to rotate at a target rotation speed within the minute rotation speed range. This prevents concentrated current flow in a single phase and reduces the temperature of the drive unit 152.

[0063] The energization control is a speed feedback control that controls the inverter 151 so that the rotating electrical machine 150 rotates at a target rotation speed within the minute rotation speed range.

[0064] If the vehicle 100 is stopped until a specific time has elapsed since the torque suppression was started, the control unit cancels the torque suppression and then executes speed feedback control.

[0065] When the control unit detects an accelerator hill hold operation, which keeps the vehicle 100 stopped by operating the accelerator pedal provided on the vehicle 100 so that the motor torque and the load torque are balanced, it outputs a warning to urge the driver of the vehicle 100 to ease up on the accelerator pedal.

[0066] 6 is a circuit diagram showing the configuration of the drive unit 152 including the rotating electric machine 150 and the inverter 151. The rotating electric machine 150 includes a stator 153, a rotor 154, a current sensor 203, and a rotation speed sensor 211. The rotating electric machine 150 is a three-phase motor generator, and the stator 153 has windings 155U, 155V, and 155W of multiple phases. The winding 155U is a U-phase winding, the winding 155V is a V-phase winding, and the winding 155W is a W-phase winding. The current sensor 203, for example, detects the current flowing through the winding 155V and the current flowing through the winding 155W. The rotation speed sensor 211 is, for example, a resolver, and detects the rotation angle and rotation speed of the rotor 154.

[0067] The inverter 151 has six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd. Hereinafter, when there is no need to distinguish between the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd, the six power elements 156Uu, 156Ud, 156Vu, 156Vd, 156Wu, and 156Wd will each be referred to as a "power element 156." Each power element 156 is, for example, a power transistor. The power elements 156Uu and 156Ud are U-phase power elements, the power elements 156Vu and 156Vd are V-phase power elements, and the power elements 156Wu and 156Wd are W-phase power elements. The power elements 156Uu and 156Ud are bridge-connected to the winding 155U, the power elements 156Vu and 156Vd are bridge-connected to the winding 155V, and the power elements 156Wu and 156Wd are bridge-connected to the winding 155W.

[0068] The inverter 151 has one temperature sensor 157. The temperature sensor 157 is provided in one of the multiple power elements 156. In the present embodiment, as an example, the temperature sensor 157 is provided in the power element 156Vu and detects the temperature of the power element 156Vu. Note that although the example in which the temperature sensor 157 is provided in the power element 156Vu is given here, the temperature sensor 157 may be provided in a power element 156 other than the power element 156Vu. Furthermore, the temperature sensor 157 may be provided in the power element 156 with the strictest heat resistance conditions among the six power elements 156. For example, if the inverter 151 has a heat dissipation mechanism, the power element 156 with the strictest heat resistance conditions corresponds to the power element with the smallest heat dissipation energy by the heat dissipation mechanism.

[0069] Next, referring to Fig. 7 , a description will be given of the protection control process executed by the CPU 21A of the control unit 21, that is, the protection control process for protecting the rotating electric machine 150 that drives the vehicle 100 by suppressing overheating of the rotating electric machine 150. The protection control process shown in Fig. 7 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0070] In step S100, the CPU 21A (temperature estimation unit 42) executes the temperature estimation process shown in Fig. 10. Details of the temperature estimation process will be described later.

[0071] In step S101, the CPU 21A (overheat protection determination unit 44) executes the overheat protection determination process shown in Fig. 14. The overheat protection determination process will be described in detail later.

[0072] In step S102, the CPU 21A (overheat protection control unit 46) executes the overheat protection control process shown in Fig. 18. The overheat protection control process will be described in detail later.

[0073] Next, a description will be given of the step-climbing control process executed by the CPU 21A of the control unit 21 with reference to Fig. 8. The step-climbing control process shown in Fig. 8 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0074] In step S200, the CPU 21A executes the permission determination process for the pedal misapplication prevention control shown in Figures 24 and 25. The permission determination process for the pedal misapplication prevention control will be described in detail later.

[0075] In step S201, the CPU 21A executes a step estimation process shown in Fig. 27. Details of the step estimation process will be described later.

[0076] In step S202, the CPU 21A executes the pedal misapplication determination process shown in Fig. 31. In the pedal misapplication determination process, the pedal misapplication protection control torque TO to be applied to the rotating electrical machine 150 is calculated and stored in the memory unit 23. The pedal misapplication protection control torque TO stored in the memory unit 23 is updated each time the bump clearance control is executed. The pedal misapplication determination process will be described in detail later.

[0077] Next, the torque selection process executed by the CPU 21A of the control unit 21 will be described with reference to Fig. 9. The torque selection process shown in Fig. 9 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0078] In step S300, CPU 21A obtains driver-requested torque TACC corresponding to the amount of accelerator pedal operation by the driver of vehicle 100 by reading it from storage unit 23. Driver-requested torque TACC is a torque value corresponding to the amount of accelerator pedal operation by the driver of vehicle 100. For example, torque map data 23B indicating the correspondence between accelerator pedal operation amount and torque value is stored in storage unit 23 in advance, and a torque value corresponding to the accelerator pedal operation amount obtained from accelerator sensor 205 is obtained from torque map data 23B and stored in storage unit 23 as driver-requested torque TACC. Driver-requested torque TACC stored in storage unit 23 is successively updated according to the amount of accelerator pedal operation by the driver.

[0079] In step S301, the CPU 21A reads out from the storage unit 23 the overheat protection control torque TH calculated by the protection control process shown in FIG.

[0080] In step S302, the CPU 21A reads out from the storage unit 23 and acquires the pedal misapplication protection control torque TO calculated by the step-clearing control process shown in FIG.

[0081] In step S303, the CPU 21A determines the final torque TMG to be applied to the rotating electric machine 150. Specifically, the CPU 21A determines the torque with the smallest torque value among the driver requested torque TACC obtained in step S300, the overheat protection control torque TH obtained in step S301, and the pedal misapplication protection control torque TO obtained in step S302 as the final torque TMG. This makes it possible to prevent excessive torque from being applied to the rotating electric machine 150.

[0082] In step S304, the CPU 21A executes the accelerator hill-hold countermeasure process shown in FIG.

[0083] Next, the temperature estimation process of step S100 in Fig. 7 will be described in detail with reference to Fig. 10. The temperature estimation process shown in Fig. 10 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec. In the following description, "*" indicates a value for each of the six power elements 156, and when the "*" is removed, it indicates a value for any of the six power elements 156 or a representative value.

[0084] In step S400, the CPU 21A determines whether the absolute value of the rotation speed of the rotating electric machine 150 is greater than a predetermined rotation speed based on the detection result of the rotation speed sensor 211. Here, the predetermined rotation speed is a rotation speed corresponding to a speed at which the vehicle 100 is considered to be traveling at an extremely low speed (i.e., a rotation speed near a stop of rotation). In the present embodiment, as an example, the predetermined rotation speed is set to 100 rpm, but is not limited to this.

[0085] If the absolute value of the rotation speed is greater than the predetermined rotation speed, the CPU 21A proceeds to step S401, and if the absolute value of the rotation speed is equal to or less than the predetermined rotation speed, the CPU 21A proceeds to step S403.

[0086] In step S401, the CPU 21A estimates the temperature estimated value TempMG* for each power element 156 (i.e., six temperature estimated values ​​corresponding to each power element 156). Here, the temperature detected value Ts of the power element 156Vu detected by the temperature sensor 157 is set as the temperature estimated value TempMG* for each power element 156. As described above, the temperature sensor 157 is provided for the power element 156 with the strictest heat resistance conditions. When the absolute value of the rotation speed is greater than a predetermined rotation speed, the thermal loads of the six power elements 156 are equal, and therefore the temperature detected value Ts of the power element 156Vu detected by the temperature sensor 157 can be considered as the temperature estimated value TempMG* for each power element 156.

[0087] In step S402, the CPU 21A selects the highest temperature estimated value TempMG from among the temperature estimated values ​​TempMG* for each power element 156.

[0088] In step S403, the CPU 21A determines whether the single-phase continuous conduction flag XUVWC* for each power element 156 (i.e., six single-phase continuous conduction flags corresponding to the power elements 156) is 1. Details of the single-phase continuous conduction flag XUVWC* will be described later. When the single-phase continuous conduction flag XUVWC* is 1, it indicates that continuous conduction is occurring in any one of the U-phase, V-phase, or W-phase of the rotating electric machine 150, which is a three-phase motor generator. In other words, when the single-phase continuous conduction flag XUVWC* is 1, it indicates that the drive unit 152 is in an overload state, causing the vehicle 100 to stop, and the drive unit 152 is in a single-phase continuous conduction state in which current continuously flows in any one of the phases. On the other hand, if the single-phase continuous energization flag XUVWC* is 0, it indicates that the energized phase has changed from one of the U phase, V phase, or W phase to another phase, i.e., the rotating electric machine 150 is rotating.

[0089] If the single-phase continuous energization flag XUVWC* is 1, the CPU 21A proceeds to step S404, and if the single-phase continuous energization flag XUVWC* is 0, the CPU 21A proceeds to step S402.

[0090] In step S404, the CPU 21A calculates ΔTup*, which indicates the temperature increase due to heat generation from the driving unit 152. ΔTup* can be calculated using the following formula.

[0091] ΔTup*=∫(k1×|iMG*|) ...(1)

[0092] Here, iMG* is the current value for each power element 156 (i.e., six current values ​​corresponding to each power element 156), and can be obtained based on the current value detected by the current sensor 203. Furthermore, k1 is a predetermined coefficient for converting the current value iMG* to temperature, and is preset as a value suitable for calculating ΔTup when the absolute value of the rotation speed is equal to or less than a predetermined rotation speed. Note that in this case, the rotation speed may be set to a fixed value of 0 rpm. As shown in the above formula, ΔTup* is calculated by integrating the heat generation amount due to the current value. ΔTup* corresponds to the heat generation energy estimated based on the current value iMG* for each power element 156. ΔTup* is calculated for each power element 156.

[0093] In step S405, the CPU 21A calculates ΔTdwn*, which indicates the temperature drop due to heat dissipation from the drive unit 152 through heat exchange with the outside. ΔTdwn* can be calculated, for example, using a predetermined calculation formula that includes the outside temperature of the vehicle 100 as a parameter. The outside temperature may be acquired from the outside temperature sensor 206. ΔTdwn* can be calculated using the following formula.

[0094] ΔTdwn*=∫(k2×|Tc−TempMG*|) ...(2)

[0095] Here, Tc is the temperature of the coolant cooling the drive unit 152 (for example, the inverter 151) and can be detected by a water temperature sensor (not shown). The coolant temperature may be a fixed value representing the maximum cooling capacity limit (e.g., 65°C). Because the maximum temperature is the temperature that can protect the components, the coolant temperature may be a fixed value representing the maximum cooling capacity limit. k2 is a predetermined coefficient for calculating ΔTdwn* and is preset as a value suitable for calculating ΔTdwn* when the absolute value of the rotation speed is equal to or lower than a predetermined rotation speed. As shown in Equation (2) above, ΔTdwn* is calculated by integrating the heat exchange with the coolant and the heat dissipation. ΔTdwn* corresponds to the heat dissipation energy estimated based on the detected temperature value Ts and the temperature of the coolant cooling the inverter 151. ΔTdwn* is calculated for each power element 156. By taking heat dissipation energy into consideration, the temperature of the drive unit 152 can be accurately estimated.

[0096] In step S406, the CPU 21A calculates the estimated temperature value TempMG* for each power element 156. TempMG* can be calculated by the following formula.

[0097] TempMG*=k3×LPF(ΔTup*−ΔTdwn*)...(3)

[0098] Here, k3 is a predetermined coefficient for calculating TempMG*, and is preset as a value suitable for calculating TempMG* when the absolute value of the rotation speed is equal to or lower than a predetermined rotation speed. LPF() is a function representing a low-pass filter. As shown in the above formula (3), TempMG* is calculated based on the idea that the energy of heat generation and the energy of heat dissipation are proportional to temperature. The time constant of the low-pass filter may be different when the temperature is rising and when the temperature is falling. TempMG* is calculated for each power element 156.

[0099] In this way, in the temperature estimation process, the temperature of the drive unit 152 is estimated based on the detected temperature values ​​of the power elements 156 and the current values ​​for each power element 156. Therefore, it is possible to accurately determine whether the drive unit 152 is overheating. As a result, in the overheat protection control process described below, control for lowering the temperature of the drive unit 152 can be performed at an appropriate timing.

[0100] Furthermore, since the temperature sensor 157 (see FIG. 6) is provided on one of the six power elements 156, costs can be reduced compared to when a temperature sensor 157 is provided on all six power elements 156.

[0101] In this embodiment, the temperature sensor 157 is provided on only one of the six power elements 156, but the temperature sensor 157 may be provided on more than one of the six power elements 156, or the temperature sensor 157 may be provided on all six power elements 156. Furthermore, for example, when the temperature sensor 157 is provided on all six power elements 156, the temperature of the drive unit 152 may be estimated based on the temperature detection value detected by each temperature sensor 157, and temperature feedback control, which will be described later, may be executed based on the estimated temperature.

[0102] 11 shows the relationship between the rotation speed of the rotating electric machine 150, the current value iMG of the power element 156, the single-phase continuous conduction flag XUVWC, and the estimated temperature value TempMG of the power element 156. Fig. 11 shows one of the current values ​​iMG* for each power element 156, one of the single-phase continuous conduction flags XUVWC* for each power element 156, and one of the estimated temperature values ​​TempMG* for each power element 156.

[0103] As described above, in the temperature estimation process, when the absolute value of the rotational speed of the rotating electric machine 150 is greater than a predetermined rotational speed (i.e., a rotational speed near the rotation stop), the estimated temperature value TempMG* for each power element 156 is estimated based on the temperature detection value Ts of the temperature sensor 157. This reduces the load on the CPU 21A compared to, for example, estimating the estimated temperature value TempMG* for each power element 156 based on the temperature detection value Ts and the current value iMG* for each power element 156. On the other hand, when the absolute value of the rotational speed of the rotating electric machine 150 is equal to or less than the predetermined rotational speed, the estimated temperature value TempMG* for each power element 156 is estimated based on the temperature detection value Ts and the current value iMG* for each power element 156. This allows the estimated temperature value TempMG* for each power element 156 to be estimated more accurately than when estimating the estimated temperature value TempMG* for each power element 156 based only on the temperature detection value Ts of the temperature sensor 157.

[0104] Furthermore, if the drive unit 152 is in an overload state, causing the vehicle 100 to stop and resulting in a single-phase continuous current flow state, the thermal load of the phase in which current is concentrated increases three times compared to when there is no overload. Therefore, if the single-phase continuous current flow state occurs, the estimated temperature value TempMG* for each power element 156 can be estimated accurately by estimating the estimated temperature value TempMG* based on the detected temperature value Ts and the current value iMG* for each power element 156.

[0105] Then, the highest temperature estimated value TempMG is selected from the temperature estimated values ​​TempMG* for each power element 156. This makes it possible to suppress the occurrence of a failure due to overheating of the drive unit 152, compared to, for example, selecting the lowest temperature estimated value TempMG* from the temperature estimated values ​​TempMG* for each power element 156. The temperature estimated value TempMG can be estimated as the temperature of the drive unit 152. The temperature of the drive unit 152 may be the temperature of the rotating electric machine 150 or the temperature of the inverter 151. Furthermore, the temperature of the drive unit 152 may be the temperatures of the rotating electric machine 150 and the inverter 151. The overheat protection determination process shown in FIG. 14 and the overheat protection control process shown in FIG. 18 are executed based on the temperature estimated value TempMG.

[0106] In the temperature estimation process according to this embodiment, in step S403, it is determined whether the single-phase continuous energization flag XUVWC* for each power element 156 is 1. However, the determination in step S403 may be omitted. Furthermore, when the determination in step S403 is omitted, the temperature estimation process may be performed as follows.

[0107] 12 shows a modified example of part of the temperature estimation process. In this modified example, steps S407 and S408 are executed instead of steps S404 to S406 of the temperature estimation process shown in FIG.

[0108] In step S407, the CPU 21A derives the saturation temperature for each power element 156. The saturation temperature is extracted from a map that defines the relationship between the saturation temperature, the absolute value of the current value iMG* for each power element 156, the temperature of the coolant, and the rotation speed of the rotating electrical machine 150. The temperature of the coolant may be set to a fixed value, such as the maximum temperature (e.g., 65°C) at the cooling capacity limit. The rotation speed of the rotating electrical machine 150 may be set to a fixed value of 0 rpm.

[0109] In step S408, the CPU 21A calculates the temperature estimate value TempMG* for each power element 156 based on the saturation temperature of each power element 156 using a function indicating a low-pass filter.

[0110] In this way, regardless of whether the rotating electrical machine 150 is in a single-phase continuous conduction state, the estimated temperature value TempMG* can be calculated for each power element 156. In other words, even when the rotation speed of the rotating electrical machine 150 is, for example, 100 rpm or less and the rotation of the rotating electrical machine 150 has not completely stopped, the estimated temperature value TempMG* can be calculated for each power element 156.

[0111] Next, the single-phase continuous energization determination process will be described with reference to Fig. 13. Note that the single-phase continuous energization determination process shown in Fig. 13 may be executed by the inverter 151.

[0112] In step S500, the CPU 21A determines whether the energized phase has changed. That is, the CPU 21A determines whether the energized phase has changed from the U phase, V phase, or W phase to another phase. If the energized phase has not changed, the CPU 21A proceeds to step S501. If the energized phase has changed, the CPU 21A proceeds to step S504.

[0113] In step S501, the CPU 21A counts up a counter T ｃｎｔ * is updated using the following formula:

[0114] T ｃｎｔ * = T ｃｎｔ *+(t ｎ -t ｎ－１ ) ... (4)

[0115] Here, t ｎ is the time when the process of FIG. 12 is executed, and t ｎ－１ is the time when the process of FIG. 9 was executed last time. ｃｎｔ * is reset in step S505, which will be described later.

[0116] In step S502, the CPU 21A counts up the counter t ｃｎｔ * is greater than a predetermined time, i.e., the counter T ｃｎｔ The CPU 21A determines whether a predetermined time has elapsed since the counter t* was reset. In the present embodiment, the predetermined time is set to 0.5 seconds as an example, but is not limited to this. ｃｎｔ If * is greater than the predetermined time, the process proceeds to step S503, and the counter t ｃｎｔ If * is equal to or less than the predetermined time, the process proceeds to step S504.

[0117] In step S503, the CPU 21A sets the single-phase continuous current supply flag XUVWC* for each power element 156 to 1.

[0118] In step S504, the CPU 21A sets the single-phase continuous conduction flag XUVWC* for each power element 156 to 0.

[0119] In step S505, the CPU 21A counts the counter T ｃｎｔ* is set to 0. That is, the counter T ｃｎｔ *Reset.

[0120] Next, the details of the overheat protection determination process in step S101 in Fig. 7 will be described with reference to Fig. 14. The overheat protection determination process shown in Fig. 14 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0121] In step S600 of Fig. 14, the CPU 21A determines whether the driver-requested torque TACC is equal to or greater than the gradient torque TU. The driver-requested torque TACC may be interpreted as the torque acquired in the process of step S300 of Fig. 9. Details of the gradient torque TU will be described in the description of the pedal misapplication determination process of Fig. 32.

[0122] The CPU 21A proceeds to step S601 when the driver required torque TACC is less than the gradient torque TU, and proceeds to step S602 when the driver required torque TACC is equal to or greater than the gradient torque TU.

[0123] In step S601, the CPU 21A sets the overheat protection control torque TH to $FF, sets the overheat protection execution flag XINVHOT to 0, and proceeds to step S607. The overheat protection execution flag XINVHOT is a flag that indicates the execution of overheat protection.

[0124] In step S602, the CPU 21A determines whether the estimated temperature value TempMG estimated in the temperature estimation process of Fig. 10 exceeds a first threshold. The first threshold is a temperature at which overheat protection control process should normally be performed, and in this embodiment, is set to 165°C as an example, but is not limited to this. If TempMG is equal to or less than the first threshold, the CPU 21A proceeds to step S601. If TempMG exceeds the first threshold, the CPU 21A proceeds to step S603.

[0125] In step S603, the CPU 21A determines whether the single-phase continuous conduction flag XUVWC* for each power element 156 is 1 or 0, that is, whether single-phase concentrated conduction is in progress. For example, if current continues to flow through a specific phase for 0.5 seconds or more, the single-phase continuous conduction flag XUVWC* changes from 0 to 1. If the single-phase continuous conduction flag XUVWC* is 0, the CPU 21A proceeds to step S604, and if the single-phase continuous conduction flag XUVWC* is 1, the CPU 21A proceeds to step S605.

[0126] In step S604, the CPU 21A executes a process for returning from torque suppression for temperature reduction. Specifically, the CPU 21A sets the overheat protection control torque TH to a value obtained by adding ΔT2 (see FIG. 17 ) to the previous value of the final torque TMG applied to the rotating electrical machine 150, and proceeds to step S607. However, the upper limit of the overheat protection control torque TH is set to the driver requested torque TACC.

[0127] In step S605, the CPU 21A executes torque suppression processing to reduce the temperature. Specifically, the CPU 21A sets the overheat protection control torque TH to a value obtained by subtracting ΔT1 (see FIG. 17 ) from the previous value of the final torque TMG applied to the rotating electrical machine 150, and proceeds to step S606. However, the lower limit of the overheat protection control torque TH is set to 0 or more.

[0128] In step S606, the CPU 21A sets the overheat protection execution flag XINVHOT to 1, and then proceeds to step S607.

[0129] In step S607, the CPU 21A executes speed feedback control for overheat protection. Specifically, the speed feedback control unit 47 controls the overheat protection control torque TH based on the vehicle speed so that the vehicle speed calculated from the wheel speed sensor becomes a predetermined target speed. The target speed is a speed in the extremely low speed range, and in this embodiment, is set to 0.5 kph to 1 kph as an example, but is not limited to this. The speed feedback control will be described in detail later.

[0130] Next, the overheat protection control process (MG power supply control) will be described with reference to Figures 15 to 17. The overheat protection control process shown in Figures 15 and 16 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0131] In FIG. 15, in step S700A, a predetermined electrical angle and phase current are set in the rotary electric machine 150 by vector control.

[0132] In step S700, the CPU 21A determines whether or not overheat protection is required. Specifically, when the overheat protection execution flag XINVHOT is 1, the accelerator pedal depression amount exceeds a predetermined amount, and the vehicle speed is lower than a predetermined speed (i.e., the vehicle speed is at a speed that can be considered as being stopped), the CPU 21A determines that overheat protection is required and proceeds to step S702. The overheat protection execution flag XINVHOT being 1 may be interpreted as indicating an MG locked state, that is, a locked state in which the rotating electric machine 150 does not rotate when current is applied to the rotating electric machine 150.

[0133] If any of these conditions is not satisfied, the CPU 21A determines that execution of overheat protection is unnecessary and proceeds to step S701. In step S701, the CPU 21A sets the same-phase continuous current-carrying time counter C to 0 (C=0), sets the number of continuous current-carrying times CC to 0 (CC=0), and sets the electrical angle forced change flag Xchg to 0 (Xchg=0), and proceeds to step S700.

[0134] In step S702, the CPU 21A determines whether the amount of change in the electrical angle of the rotary electric machine 150 is small. Specifically, the CPU 21A determines whether the value of the current electrical angle is less than a value corresponding to the previous value + α and greater than a value corresponding to the previous value - α. The value corresponding to the previous value + α may be interpreted as the electrical angle obtained by adding a predetermined value to the value of the previous electrical angle. The value corresponding to the previous value - α may be interpreted as the electrical angle obtained by subtracting a predetermined value from the value of the previous electrical angle.

[0135] If the value of the current electrical angle is not less than the value corresponding to the previous value + α or does not exceed the value corresponding to the previous value - α, the CPU 21A proceeds to step S703, and if the value is less than the value corresponding to the previous value + α and exceeds the value corresponding to the previous value - α, the CPU 21A proceeds to step S704.

[0136] In step S703, the CPU 21A sets a same-phase continuous current application time counter C to 0 (C=0), and the process proceeds to step S705.

[0137] In step S704, the CPU 21A increments the number of continuous energizations CC (C++), and proceeds to step S705.

[0138] In step S705, the CPU 21A determines whether the value of the same-phase continuous energization time counter C is equal to or greater than a predetermined time. The predetermined time is, for example, 30 msec. If the value of the same-phase continuous energization time counter C is less than the predetermined time, the CPU 21A proceeds to step S711 (FIG. 16). If the value of the same-phase continuous energization time counter C is equal to or greater than the predetermined time, the CPU 21A proceeds to step S706.

[0139] In step S706, the CPU 21A stores the electrical angle during continuous current supply to the same phase in the storage unit 23, and then proceeds to step S707. Specifically, the CPU 21A stores the rotor electrical angle during continuous current supply to the same excitation phase (Reijisou).

[0140] In step S707, the CPU 21A determines whether the number of consecutive energizations CC exceeds 0, i.e., whether this is the first overheat protection. If the number of consecutive energizations CC does not exceed 0, the CPU 21A proceeds to step S711. If the number of consecutive energizations CC exceeds 0, the CPU 21A proceeds to step S708.

[0141] In step S708, the CPU 21A determines whether the current energized phase is the same as the previous continuous energized phase (Reijisouo). Specifically, the CPU 21A determines whether the current electrical angle is less than the electrical angle corresponding to (Reijisouo+α) and greater than the electrical angle corresponding to (Reijisouo-α).

[0142] If the current electrical angle value is not less than the electrical angle corresponding to Reijisouo+α or does not exceed the electrical angle corresponding to Reijisouo-α, the CPU 21A proceeds to step S709. If the current electrical angle value is less than the electrical angle corresponding to Reijisouo+α and exceeds the electrical angle corresponding to Reijisouo-α, the CPU 21A proceeds to step S710.

[0143] In step S709, the CPU 21A sets the electrical angle forced change flag Xchg to 0 (Xchg=0), and proceeds to step S711.

[0144] In step S710, the CPU 21A sets the electrical angle forced change flag Xchg to 1 (Xchg=1), and proceeds to step S711, whereby control to avoid continuous energization of the same phase can be started.

[0145] 16, the CPU 21A determines whether the MG locked state has been released, that is, whether the single-phase continuous energization flag XUVWC* is 1 or 0. If the MG locked state has not been released, the CPU 21A proceeds to step S714, and if the MG locked state has been released, the CPU 21A proceeds to step S712.

[0146] In step S712, the CPU 21A increments the number of continuous energizations CC (C++), and proceeds to step S713.

[0147] In step S713, the CPU 21A updates the previous continuous energized phase (Reijisouo) to the previously stored energized phase (Reijisou), and proceeds to step S714.

[0148] In step S714, the CPU 21A determines whether the electrical angle forced change flag Xchg is 1 or 0. If the electrical angle forced change flag Xchg is 1 (Xchg=1), the CPU 21A proceeds to step S715, and if the electrical angle forced change flag Xchg is 0 (Xchg=0), the CPU 21A ends this routine.

[0149] In step S715, the CPU 21A forcibly changes the electrical angle. Specifically, the CPU 21A changes the electrical angle to an electrical angle obtained by adding a predetermined value β to the previous electrical angle, and then proceeds to step S716. The predetermined value β is, for example, 120°.

[0150] In step S716, the CPU 21A determines whether the electrical angle is equal to or greater than a predetermined electrical angle. Specifically, if the electrical angle changed in step S715 is equal to or greater than the electrical angle (Reijisou+120) obtained by adding 120° to the same phase angle updated in step S713, the CPU 21A proceeds to step S717. If the electrical angle is less than the electrical angle (Reijisou+120), the CPU 21A proceeds to step S718.

[0151] In step S717, the CPU 21A sets the electrical angle to, for example, the electrical angle obtained by adding 120° to the previous continuously energized phase (Reijisouo+120) in order to change the electrical angle up to the phase adjacent to the currently excited phase, and then proceeds to step S718.

[0152] In step S718, the CPU 21A determines whether the electrical angle exceeds 360. If the electrical angle is equal to or less than 360, the CPU 21A proceeds to step S720, and if the electrical angle exceeds 360, the CPU 21A proceeds to step S719.

[0153] In step S719, the CPU 21A updates the electrical angle to a value obtained by subtracting 360° from the electrical angle, and then proceeds to step S720.

[0154] In step S720, the CPU 21A determines whether a new lock determination has been made, that is, whether the MG is in a locked state. If the MG is in a locked state, the CPU 21A proceeds to step S721, and if the MG is not in a locked state, the CPU 21A ends this routine.

[0155] In step S721, the CPU 21A sets the electrical angle forced change flag Xchg to 0 (Xchg=0), thereby stopping the process of forcibly changing the electrical angle.

[0156] FIG. 17 shows the accelerator pedal operation amount (accelerator), vehicle speed, electrical angle, lock determination, torque of the rotary electric machine 150 (MG torque), temperature of the power element 156 (power transformer temperature), same phase continuous energization time counter (C), number of continuous energizations (CC), same phase (Reijisou), previous continuously energized phase (Reijisouo), electrical angle forced change flag (Xchg), overheat protection execution flag (XINVHOT), etc.

[0157] When the overheat protection control process shown in FIGS. 15 and 16 is not executed, the electrical angle remains low, as indicated by the dotted line. In this case, a single-phase continuous conduction state occurs, in which current flows continuously and concentrates in the same phase (specific phase), and the temperature of the power elements 156 rises to a high value, as indicated by the dotted line ( FIG. 17 ). In contrast, when the overheat protection control process is executed, the electrical angle is forcibly changed during the period when Xchg = 1, as indicated by the thick solid line ( FIG. 17 ). By shifting the electrical angle at which current flows in a specific phase, the current is distributed among multiple phases included in the rotating electric machine 150, thereby avoiding a state in which current flows in a specific phase, i.e., a single-phase continuous conduction state. Therefore, the temperature of the power elements 156 of the specific phase falls to a low value, as indicated by the thick solid line ( FIG. 17 ).

[0158] (Modified Overheat Protection Control Process) Next, a modified overheat protection control process (constant speed drive process) will be described with reference to Figures 18 to 20. The overheat protection control process shown in Figures 18 and 19 is a process that is repeatedly executed at predetermined time intervals, for example, every 10 msec.

[0159] The differences from the flowcharts shown in Figures 15 and 16 are that the flowcharts shown in Figures 18 and 19 omit the processes of steps S706, S708, S709, S713, S716, S717, S720, and S721, and that the process of step S715A is executed instead of the process of step S715.

[0160] 19, the CPU 21A changes the electrical angle to an electrical angle obtained by adding a predetermined value γ to the previous electrical angle, and then proceeds to step S718. The predetermined value γ may be a value smaller than the above-mentioned predetermined value β, for example, a specific value ranging from several degrees to several tens of degrees.

[0161] The constant speed drive process shown in Figures 18 and 19 may be executed after the vehicle 100 has been braked to a stop as a countermeasure for accelerator hill hold. Accelerator hill hold refers to the act of keeping the vehicle 100 stopped by operating the accelerator pedal provided on the vehicle 100 when the vehicle 100 is going over a step or traveling uphill. During accelerator hill hold, the throttle valve is in a wide open state (accelerator WOT: Wide Open Throttle). As a countermeasure for such accelerator hill hold, a warning may be issued to prompt the driver to release the accelerator and brake to stop the vehicle. Therefore, the constant speed drive process may be prohibited until the vehicle 100 has been braked to a stop, and the constant speed drive process may be executed only after the vehicle has been braked to a stop. This prevents the constant speed drive process from conflicting with the accelerator hill hold countermeasure.

[0162] FIG. 20 shows the accelerator pedal operation amount (accelerator), vehicle speed, electrical angle, lock determination, torque of the rotary electric machine 150 (MG torque), temperature of the power element 156 (power transformer temperature), overheat protection execution flag (XINVHOT), same-phase continuous current supply time counter (C), number of continuous current supplies (CC), and electrical angle forced change flag (Xchg).

[0163] When the constant speed driving process is not executed, the electrical angle changes as shown by the dotted line, so that current continues to flow in a concentrated manner in a specific phase, and the temperature of the power element 156 becomes a high value as shown by the dotted line.

[0164] In contrast, when the constant speed drive process is executed, the electrical angle is changed smoothly during the period when Xchg = 1, as indicated by the thick solid line. Specifically, compared to the electrical angle indicated by the thick solid line in FIG. 17 , the electrical angle is changed multiple times in a short period of time. That is, the electrical angle is changed smoothly, similar to when the rotating electric machine 150 is driven at a constant speed. The MG torque at this time is not suppressed, as indicated by the thick solid line. Note that the MG torque indicated by the dotted line is the torque when torque suppression control is executed. In this way, the constant speed drive process can avoid continuous current flow concentrated in the same phase (specific phase) without torque suppression, and therefore the temperature of the power element 156 becomes a low value, as indicated by the thick solid line.

[0165] Note that the processes shown in FIGS. 15 and 16 may be executed first, followed by the processes shown in FIGS. 18 and 19 . For example, the processes shown in FIGS. 15 and 16 may switch the single-phase concentrated phase and continue torque suppression control, thereby increasing the chances of surmounting a bump or other obstacle. If this process still fails to surmount a bump or other obstacle, the processes shown in FIGS. 18 and 19 may be executed. This allows the electrical angle to be smoothly changed, further increasing the chances of surmounting a bump or other obstacle. Furthermore, by continuing the current switching while preventing single-phase concentrated current, the temperature of the power element 156 can be lowered without suppressing torque. At this time, the driver is significantly depressing the accelerator pedal, indicating their intention to surmount a bump or other obstacle. However, even if the engine is rotated at a slow speed, control can be performed in accordance with the driver's intention. In this way, overheating protection is achieved to protect components, while ensuring drivability and reliably surmounting a bump or other obstacle. Furthermore, safety can be ensured by preventing the vehicle 100 from jumping out after surmounting a bump.

[0166] The following describes continuous energization switching control using speed feedback control. (Overview of Speed ​​Feedback Control) Normally, when the rotating electric machine 150 stops rotating and a single-phase concentrated energization occurs, the thermal load increases. To avoid this, the thermal load is evenly distributed across multiple phases (e.g., three phases) of the locked rotating electric machine 150, thereby reducing the thermal load of the concentrated phase where energization is concentrated by one-third. Furthermore, maximum torque can be generated. Therefore, the vehicle control device 10 of the present disclosure may use speed feedback control to continuously switch energization phases, for example, in the order of U, V, and W phases, so that the rotating electric machine 150 continues to rotate at a slow speed with maximum torque without torque limiting (current limiting). When the target hill-climbing performance is achieved, normal control is restored. Speed ​​feedback control will be described with reference to Figures 21 to 23 .

[0167] The speed feedback control may be executed after the vehicle 100 has been stopped by braking as part of the accelerator hill-hold countermeasure described above, thereby preventing the speed feedback control from competing with the accelerator hill-hold countermeasure.

[0168] 22, in step S800, CPU 21A determines whether the gradient of the road surface detected by gradient sensor 207 exceeds a predetermined value. If the gradient is equal to or smaller than the predetermined value, CPU 21A proceeds to step S801, and if the gradient exceeds the predetermined value, CPU 21A proceeds to step S802.

[0169] In step S801, the CPU 21A sets the speed feedback execution flag XINVHOTFB to 0, and ends this routine. The speed feedback execution flag XINVHOTFB may be interpreted as a flag indicating whether or not the speed feedback control process shown in FIG. 22 is being executed.

[0170] In step S802, the CPU 21A determines whether the vehicle speed is equal to or less than a predetermined speed. The predetermined speed is set to a speed at which it can be determined that the vehicle 100 is traveling at a low speed, and in this embodiment, it is set to 1 kph as an example, but is not limited to this. If the vehicle speed exceeds the predetermined speed, the CPU 21A proceeds to step S801. If the vehicle speed is equal to or less than the predetermined speed, the CPU 21A proceeds to step S803.

[0171] In step S803, the CPU 21A determines whether the absolute value of the difference between the driver requested torque TACC and the gradient torque TU exceeds a predetermined value.

[0172] If the absolute value is equal to or smaller than the predetermined value, the CPU 21A proceeds to step S801, and if the absolute value exceeds the predetermined value, the CPU 21A proceeds to step S804.

[0173] In step S804, the CPU 21A sets the overheat protection control torque TH and controls the torque so that the vehicle speed becomes a target speed (for example, 1 kph). That is, the CPU 21A releases the restriction on the overheat protection control torque TH and performs speed feedback control so that the vehicle speed becomes a target speed in the extremely low speed range. The target vehicle speed is set to, for example, 1 kph, but is not limited to this.

[0174] In step S805, the CPU 21A sets the speed feedback execution flag XINVHOTFB to 1.

[0175] 23 shows the accelerator pedal depression amount (accelerator), vehicle speed, electrical angle, lock determination, torque of the rotary electric machine 150 (MG torque), temperature of the power element 156 (power transformer temperature), overheat protection execution flag (XINVHOT), speed feedback execution flag (XINVHOTFB), etc. During the period in which the speed feedback execution flag XINVHOTFB is 1, the electrical angle is changed as shown by the thick solid line. Specifically, the energized phase is repeatedly switched in the order of, for example, the U phase, V phase, and W phase so that the rotary electric machine 150 continues to rotate at a slow speed with maximum torque without torque limiting (current limiting).

[0176] Next, the accelerator hill-hold countermeasure processing in step S304 of FIG. 9 will be described with reference to FIG.

[0177] In step S900, the CPU 21A determines whether the gradient of the road surface exceeds a predetermined value. If the gradient is equal to or less than the predetermined value, the CPU 21A ends this routine. If the gradient exceeds the predetermined value, the CPU 21A proceeds to step S901.

[0178] In step S901, the CPU 21A determines whether the vehicle speed is equal to or lower than a predetermined speed. If the vehicle speed exceeds the predetermined speed, the CPU 21A ends this routine. If the vehicle speed is equal to or lower than the predetermined speed, the CPU 21A proceeds to step S902.

[0179] In step S902, the CPU 21A determines whether the absolute value of the difference between the driver required torque TACC and the gradient torque TU is equal to or less than a predetermined value. If the absolute value exceeds the predetermined value, the CPU 21A ends this routine. If the absolute value is equal to or less than the predetermined value, the CPU 21A proceeds to step S903.

[0180] In step S903, the CPU 21A sets the speed feedback execution flag XINVHOTFB to 0, and proceeds to step S904. In step S904, the CPU 21A sets the final torque TMG to 0, and proceeds to step S905.

[0181] In step S905, the CPU 21A outputs a hill hold request instruction to the brake ECU 20 that controls the brake devices 131 and 132, and the process proceeds to step S906. This instruction may be interpreted as an instruction to stop the vehicle 100 by applying the brakes rather than by operating the accelerator pedal.

[0182] In step S906, the CPU 21A outputs an instruction to the meter display system to output a warning. The warning in this case is a warning to the driver of the vehicle 100, such as a message such as "Please release the accelerator and apply the brakes to stop the vehicle." Note that the warning may be output to a system other than the meter display system (for example, an audio playback system).

[0183] Next, the details of the permission determination process for the pedal misapplication prevention control in step S200 of Fig. 8 will be described with reference to Fig. 25 and Fig. 26. Fig. 25 shows the permission determination process for determining whether or not to permit the pedal misapplication prevention control, and Fig. 26 shows the prohibition determination process for determining whether or not to prohibit the pedal misapplication prevention control.

[0184] In step S900, the CPU 21A determines whether the vehicle speed is equal to or lower than a predetermined speed. The predetermined speed is set to a relatively low speed. In this embodiment, the predetermined speed is set to 9 kph as an example, but is not limited to this. If the vehicle speed is equal to or lower than the predetermined speed, the CPU 21A proceeds to step S901. If the vehicle speed is higher than the predetermined speed, the CPU 21A proceeds to step S909 in FIG. 26.

[0185] In step S901, the CPU 21A determines whether the accelerator depression is greater than the determination threshold. The predetermined threshold is determined based on the determination threshold map data 23C. FIG. 27 shows an example of the determination threshold map data 23C for the accelerator depression. As shown in FIG. 27, the determination threshold map data 23C includes a permission determination processing map M1 and a prohibition determination map M2. The horizontal axis of FIG. 27 represents the road surface gradient, and the vertical axis represents the determination threshold, with the determination threshold varying depending on the road surface gradient. As shown in FIG. 27, the permission determination processing map M1 sets the determination threshold to a maximum value in regions where the downward gradient is too steep and regions where the upward gradient is too steep. Furthermore, in regions other than regions where the downward gradient is too steep and regions where the upward gradient is too steep, the determination threshold gradually increases in regions where the gradient changes from downward to flat, and remains approximately constant in regions where the gradient is flat. Furthermore, the determination threshold gradually increases in regions where the gradient changes from flat to upward. In the prohibition determination map M2, the determination threshold is approximately 0 in the region where the gradient ranges from a downward slope to a certain degree of upward slope, and the determination threshold gradually increases from that region to the region where the gradient increases further.

[0186] In this way, the determination threshold is set according to the gradient of the road surface. Therefore, in step S901, the CPU 21A first acquires the accelerator opening and the gradient of the road surface. The accelerator opening can be acquired from the accelerator sensor 205. The road gradient can be acquired from the gradient sensor 207. Next, the CPU 21A acquires a determination threshold corresponding to the acquired gradient of the road surface from the permission determination processing map M1. Then, the CPU 21A determines whether the accelerator opening is greater than the determination threshold. If the accelerator opening is greater than the determination threshold, the CPU 21A proceeds to step S902. If the accelerator opening is equal to or less than the determination threshold, the CPU 21A proceeds to step S909 in FIG. 26.

[0187] In step S902, the CPU 21A determines whether the brake hydraulic pressure is equal to or lower than a predetermined threshold. The brake hydraulic pressure can be obtained from the brake sensor 208. The predetermined threshold is set to a value that allows the brakes of the vehicle 100 to be determined to be off if the brake hydraulic pressure is equal to or lower than the predetermined threshold. If the brake hydraulic pressure is equal to or lower than the predetermined threshold, that is, if the brakes of the vehicle 100 are off, the CPU 21A proceeds to step S903. If the brake hydraulic pressure is greater than the predetermined threshold, that is, if the brakes of the vehicle 100 are on, the CPU 21A proceeds to step S909 in FIG. 26.

[0188] In step S903, the CPU 21A determines whether or not the parking brake of the vehicle 100 is off. Whether or not the parking brake is off can be obtained from the parking sensor 209. If the parking brake is off, the CPU 21A proceeds to step S904, and if the parking brake is on, the CPU 21A proceeds to step S909 in FIG. 26 .

[0189] In step S904, the CPU 21A determines whether the shift lever of the vehicle 100 is in a mode other than parking or neutral. That is, the CPU 21A determines whether the shift lever is in a mode in which the vehicle 100 can travel, such as drive or reverse. If the shift lever of the vehicle 100 is in a mode other than parking or neutral, the CPU 21A proceeds to step S905. If the shift lever of the vehicle 100 is not in a mode other than parking or neutral, the CPU 21A proceeds to step S909 in FIG. 26.

[0190] In step S905, the CPU 21A determines whether the counter CXHUMI, which is a counter for determining the time during which the pedal misapplication prevention control is permitted, is equal to or less than a predetermined time. In this embodiment, the predetermined time is set to 1 second as an example, but is not limited to this. If the counter CXHUMI is equal to or less than the predetermined time, the CPU 21A proceeds to step S906. If the counter CXHUMI exceeds the predetermined time, the CPU 21A proceeds to step S909 in FIG. 26.

[0191] In step S906, the CPU 21A determines whether the CRETRY counter, which counts the time elapsed since the last time the pedal misapplication prevention control was prohibited, is equal to or greater than a predetermined time. In this embodiment, the predetermined time is set to 30 seconds as an example, but is not limited to this. If the CRETRY counter is equal to or greater than the predetermined time, the CPU 21A proceeds to step S907. If the CXHUMI counter is less than the predetermined time, the CPU 21A proceeds to step S909 in FIG. 26.

[0192] In step S907, XHUMI, which is a flag indicating whether or not execution of pedal misapplication prevention control is permitted, is set to 1. When XHUMI is 1, execution of pedal misapplication prevention control is permitted. On the other hand, when XHUMI is 0, execution of pedal misapplication prevention control is prohibited.

[0193] In step S908, the CPU 21A increments the counter CXHUMI according to the following formula.

[0194] CXHUMI=CXHUMI+1...(5)

[0195] In step S909 of Figure 26, the CPU 21A determines whether the flag XHUMI is 1. That is, it determines whether the execution of the pedal misapplication prevention control is permitted. If the flag XHUMI is 1, that is, the execution of the pedal misapplication prevention control is permitted, the CPU 21A proceeds to step S910. On the other hand, if the flag XHUMI is 0, that is, the execution of the pedal misapplication prevention control is prohibited, the CPU 21A proceeds to step S915.

[0196] In step S910, the CPU 21A determines whether the accelerator opening is 0%. If the accelerator opening is 0%, the process proceeds to step S911. If the accelerator opening is not 0%, the process proceeds to step S916.

[0197] In step S911, the CPU 21A determines whether the vehicle speed is 0 kph. If the vehicle speed is 0 kph, the process proceeds to step S912, and if the vehicle speed is not 0 kph, the process proceeds to step S916.

[0198] In step S912, the CPU 21A determines whether the brake oil pressure is greater than a predetermined threshold value. If the brake oil pressure is greater than the predetermined threshold value, i.e., the brake is on, the CPU 21A proceeds to step S913, and if the brake oil pressure is equal to or less than the predetermined threshold value, i.e., the brake is off, the CPU 21A proceeds to step S916.

[0199] In step S913, the CPU 21A sets the flag XHUMI to 0. That is, the CPU 21A prohibits the execution of the mis-pedal prevention control.

[0200] In step S914, the CPU 21A sets the counter CRETRY to 0. That is, the counter CRETRY is reset.

[0201] In step S915, the CPU 21A increments the counter CRETRY according to the following formula.

[0202] CRETRY=CRETRY+1...(6)

[0203] In step S916, the CPU 21A determines whether the driver's request for crossing a step is on. Whether the driver's request for crossing a step is on may be determined, for example, by providing a release switch and determining whether the driver has turned on the release switch. Alternatively, whether the driver's request for crossing a step is on may be determined based on whether the driver has operated a turn signal. This is because if the driver has operated a turn signal, it is considered that the driver intends to drive the vehicle 100 onto, for example, a shoulder with a step. Then, if the driver's request for crossing a step is on, the CPU 21A proceeds to step S918, and if the driver's request for crossing a step is off, the CPU 21A proceeds to step S917.

[0204] In step S917, the CPU 21A determines whether the counter CXHUMI has exceeded a predetermined time. In this embodiment, the predetermined time is set to 10 seconds, for example, but is not limited to this. If the counter CXHUMI has exceeded the predetermined time, the CPU 21A proceeds to step S918. If the counter CXHUMI is equal to or less than the predetermined time, the CPU 21A ends this routine.

[0205] In step S918, the CPU 21A sets the flag XHUMI to 0. That is, the CPU 21A prohibits the execution of the mis-pedal prevention control.

[0206] In step S919, the CPU 21A sets the counter CXHUMI to 0. That is, the counter CXHUMI is reset.

[0207] In this way, permission to execute the pedal misapplication prevention control is accepted until one second has elapsed since the accelerator pedal was operated. Furthermore, if it is determined that the vehicle 100 has stopped due to factors such as releasing the accelerator, execution of the pedal misapplication prevention control is prohibited. For example, if the driver absolutely needs to get out of a hole with the wheels stuck, or if there is an obstacle ahead of the vehicle and the driver absolutely needs to get over it, or if the driver absolutely needs to get over a step on the shoulder of the road to parallel park, the pedal misapplication prevention control is prohibited and torque control by accelerator operation is restored.

[0208] In addition, if it is detected that the accelerator is depressed again after the accelerator operation is off and the accelerator misapplication prevention control has been prohibited, it may be assumed that the driver wishes to release the accelerator, and the accelerator misapplication prevention control may be prohibited again.

[0209] Next, the step estimation process in step S201 of FIG. 8 will be described in detail with reference to FIG.

[0210] In step S1000, the CPU 21A determines whether the flag XHUMI is 1, i.e., whether execution of the pedal misapplication prevention control is permitted. If the flag XHUMI is 1, i.e., if the pedal misapplication prevention control is permitted, the CPU 21A proceeds to step S1001, and if the flag XHUMI is 0, i.e., if the pedal misapplication prevention control is prohibited, the CPU 21A ends this routine.

[0211] In step S1001, the CPU 21A calculates the maximum value h of the step height h. ｍａｘ Specifically, first, the vertical load Fz is calculated. The vertical load Fz is a force applied downward to the wheels 111 and 112, which are driven wheels. The vertical load Fz is calculated as the sum of the forces applied to the wheels 111 and 112, respectively, using the following formula:

[0212] ... (7)

[0213] "m" in the first term on the right side of the above equation (7) is the weight of the vehicle 100. "g" is the gravitational acceleration. "l" is the length of the wheelbase of the vehicle 100. "lr" is the length along the front-rear direction from the center of gravity of the vehicle 100 to the central axis of rotation of the rear wheels (wheels 121, 122). Ｘ " is the acceleration in the direction of travel of the vehicle 100, i.e., the front-to-rear direction. ｃｇ " is the height from the road surface to the center of gravity of the vehicle 100. The first term on the right side of the above equation (7) represents the downward component of the force applied to each of the wheels 111 and 112 as a dynamic load when the vehicle 100 is traveling.

[0214] ​The second term on the right side of the above equation (7) is "d Ｓ " is the damping coefficient of the damper (not shown) of the vehicle 100. Ｓｐｄ " is the traveling speed of the vehicle 100 in the longitudinal direction. Ｓ can be calculated based on a signal from the wheel speed sensor 201, for example. ｏｌｄ " is the value of the trajectory angle θ calculated in the previous control cycle. When the process of FIG. 28 is executed for the first time, θ ｏｌｄ For example, 0 is used as the value of the damper. The second term on the right side of the above equation (7) represents the force applied to each of the wheels 111 and 112 as the damper expands and contracts.

[0215] Next, the trajectory angle θ is calculated. Here, the trajectory angle θ will be explained. The "trajectory angle" is the angle that the trajectory of the rotational center axis of the wheel 111 or the like makes with respect to the road surface.

[0216] Figure 29 schematically illustrates a state in which wheel 111 is on road surface RD. A step ST, which serves as a wheel stopper, is provided on road surface RD, and part of wheel 111 is in contact with step ST. If vehicle 100 attempts to move further to the right (i.e., toward step ST) from the state in Figure 29, wheel 111 will climb up onto step ST.

[0217] The graph shown by the solid line in Figure 30(A) represents the relationship between the distance traveled by the vehicle 100 (horizontal axis) and the height of the rotation center axis AX of the wheel 111 (vertical axis) when the vehicle 100 travels toward the right as described above. The graph can be said to represent the trajectory of the rotation center axis AX while the vehicle 100 is traveling. θ shown in Figure 30(A) is the angle that the trajectory of the rotation center axis AX of the wheel 111, etc., makes with the road surface, and represents the trajectory angle when the vehicle 100 is at position X1. Such a trajectory angle θ can be defined corresponding to each position of the vehicle 100.

[0218] As mentioned above, the "trajectory angle" refers to the angle that the trajectory of the rotation center axis AX of the wheel 111 or the like makes with respect to the road surface. However, the "trajectory of the rotation center axis AX" referred to here refers to the trajectory of the rotation center axis AX when the vehicle 100 is viewed in its left-right direction (vehicle width direction). The trajectory of the rotation center axis AX as shown in the graph of Figure 30(A) reflects to some extent the shape of the step ST indicated by the dashed line in the figure. The reason why the two shapes are different is that the wheel 111 is not a rigid body, and the wheel 111 deforms when it hits the step ST.

[0219] The trajectory angle θ can be calculated by the following formula.

[0220] ...(8)

[0221] "T" on the right side of the above equation (8) ｍｇ " is the torque of the rotating electric machine 150, and "R" is the radius of motion of the wheel 111. ｍｇ / R" indicates the driving force applied to the road surface by the driving wheels of the vehicle 100. The torque T ｍｇ can be obtained by, for example, obtaining the value of the driving current flowing through the rotating electrical machine 150 using the current sensor 203 and calculating the torque based on the magnitude of the obtained driving current.

[0222] Next, the trajectory angle θ′ when the wheel 111 is an ideal disk is calculated from the trajectory angle θ using the following equation.

[0223] ...(9)

[0224] Here, L is the ground contact length of the wheel 111. The ground contact length L is the climbing distance (x2-x1) in Figures 30(A) and (B). The graph in Figure 30(B) shows an example of the change in the trajectory angle θ when the vehicle 100 climbs over a step ST as in Figure 29(A).

[0225] "X1" shown in Figures 30(A) and (B) is the position of the vehicle 100 at the time when the wheel 111 etc. contacts the step ST. Also, "X2" shown in Figures 30(A) and (B) is the position of the vehicle 100 at the time when the wheel 111 etc. leaves the road surface. This position corresponds to the inflection point in the graph of Figure 30(A) and the peak value in the graph of Figure 30(B).

[0226] The "climbing distance" is the distance from X1 to X2, that is, the distance traveled by the vehicle 100 from when the wheel 111 etc. contacts the step ST until the wheel 111 etc. leaves the road surface. In other words, the "climbing distance" can also be defined as the distance traveled by the vehicle 100 during the period from when the trajectory angle θ starts to increase until when it starts to decrease.

[0227] The run-up distance defined in this way correlates with the length (L1 in FIG. 29) of the portion of the wheel 111, etc. that is in contact with the road surface RD when the vehicle 100 is parked on a flat road surface RD. Therefore, the lower the air pressure of the wheel 111, etc., the longer L1 shown in FIG. 29 becomes, and the run-up distance shown in FIGS. 30(A) and 30(B) also tends to become longer.

[0228] If the wheel 111 is an ideal disk, the height h of the step ST can be calculated by the following formula.

[0229] ...(10)

[0230] Here, θ in the above equation (10) is set to θ, which is the maximum value of the trajectory angle θ. ｍａｘ In this case, the maximum value of the height of the step ST is h ｍａｘ can be calculated.

[0231] Trajectory angle θ ｍａｘ can be calculated by the following formula:

[0232] θ ｍａｘ = κ × L (11)

[0233] Here, κ is the rate of change of the trajectory angle θ, and can be calculated by the following formula.

[0234] ...(12)

[0235] Here, filter() is a function that performs a filter process to attenuate high frequency components, and has the function of smoothing, i.e., easing, the amount of change in the trajectory angle θ. ｘ is the vehicle speed.

[0236] From the above, the maximum value of the height of the step ST is h ｍａｘ can be calculated by the following formula:

[0237] ...(13)

[0238] In the following, the maximum value h of the height of the step ST ｍａｘ is simply referred to as the height h of the step ST.

[0239] In step S1002, the CPU 21A executes a one-wheel or two-wheel climb-up determination process shown in FIG.

[0240] In step S1100, the CPU 21A determines whether the step height h calculated in step S1001 of Fig. 28 is equal to or less than a predetermined height. In this embodiment, the predetermined height is set to 2 cm, for example, but is not limited to this. If the step height h is equal to or less than the predetermined height, the CPU 21A proceeds to step S1101. If the step height h is higher than the predetermined height, the CPU 21A proceeds to step S1102.

[0241] In step S1101, a flag XKATARIN, which indicates whether one wheel or both wheels are attempting to go over the step ST, is set to 0. When the flag XKATARIN is 0, it indicates that both wheels are attempting to go over the step ST, and when the flag XKATARIN is 1, it indicates that one wheel is attempting to go over the step ST.

[0242] In step S1102, the CPU 21A calculates the lateral G proportional value δ using the following equation.

[0243] ...(14)

[0244] Here, Gｙ is the lateral G, i.e., the acceleration in the left-right direction of the vehicle 100, and can be acquired from the acceleration sensor 202. K is a predetermined coefficient. ｘ is the vehicle speed, r is the yaw rate, which can be acquired from the yaw rate sensor 210, and const is a predetermined coefficient for preventing the denominator from becoming zero.

[0245] When one wheel runs over a step ST, the vehicle 100 leans more than when both wheels run over it, and this is detected as lateral G. Also, in order to cancel the lateral G generated when the vehicle 100 turns, it is determined whether one wheel or both wheels are going over the step ST based on a lateral G proportional value δ obtained by comparing the lateral G with the lateral G calculated from the yaw rate r.

[0246] In step S1103, the CPU 21A determines whether the absolute value of the lateral G proportional value δ calculated in step S1002 is greater than a predetermined value. If the absolute value of the lateral G proportional value δ is greater than the predetermined value, the CPU 21A proceeds to step S1104. If the absolute value of the lateral G proportional value δ is equal to or less than the predetermined value, the CPU 21A proceeds to step S1101.

[0247] In step S1104, the CPU 21A sets the flag XKATARIN to 1.

[0248] 28, in step S1003, the CPU 21A determines whether the flag XKATARIN is 0. That is, the CPU 21A determines whether both wheels are about to go over a step ST. If the flag XKATARIN is 0, the CPU 21A ends this routine. If the flag XKATARIN is 1, the CPU 21A proceeds to step S1004.

[0249] In step S1004, the CPU 21A doubles the height h of the step ST using the following formula: That is, if one wheel is going over the step ST, the height h of the step ST is set to double.

[0250] h=h×2...(15)

[0251] Next, the details of the mis-pedal determination process in step S202 in Fig. 8 will be described with reference to Fig. 32. Note that the following description will be given for the case where the shift is in the D range (forward).

[0252] In step S1200, the CPU 21A determines whether the flag XHUMI is 1. That is, whether the execution of the pedal misapplication prevention control is permitted. If the flag XHUMI is 1, that is, if the execution of the pedal misapplication prevention control is permitted, the CPU 21A proceeds to step S1201. If the flag XHUMI is 0, that is, if the execution of the pedal misapplication prevention control is prohibited, the CPU 21A proceeds to step S1208.

[0253] In step S1201, the CPU 21A determines whether the vehicle speed is equal to or lower than a predetermined speed. The predetermined speed is set to a speed at which it can be determined that the vehicle 100 is traveling at a low speed. In this embodiment, the predetermined speed is set to 1 kph as an example, but is not limited to this.

[0254] If the vehicle speed is equal to or less than the predetermined speed, the CPU 21A proceeds to step S1202, and if the vehicle speed exceeds the predetermined speed, the CPU 21A proceeds to step S1204.

[0255] In step S1202, the CPU 21A determines whether the height h of the step ST is higher than a first predetermined height. In this embodiment, the first predetermined height is set to 13.5 cm, for example, but is not limited to this. If the height h of the step ST is higher than the first predetermined height, the CPU 21A proceeds to step S1203. If the height h of the step ST is equal to or less than the first predetermined height, the CPU 21A proceeds to step S1204.

[0256] In step S1203, the CPU 21A executes the overtaking prohibition control shown in FIG.

[0257] In step S1300, the CPU 21A sets a target vehicle speed. In this embodiment, the target vehicle speed is set to 0 kph, for example, but is not limited to this.

[0258] In step S1301, the CPU 21A calculates a feedback drive torque Tfb using the following equation for performing PI feedback control so that the vehicle speed becomes the target vehicle speed set in step S1300.

[0259] ...(16)

[0260] Here, Kp is a proportional gain, Ki is an integral gain, and Tfb is limited between a predetermined upper limit and a predetermined lower limit.

[0261] In step S1302, the CPU 21A sets a step correction torque TL that cancels out the load torque corresponding to the height h of the step ST. Here, TL is set to 0 when the target vehicle speed is 0 kph.

[0262] In step S1303, the CPU 21A calculates the torque TO for the mis-pedal protection control by the following equation.

[0263] TO=Tfb+TL+TU...(17)

[0264] Here, TU is a torque that is set according to the gradient of the road surface, and the correspondence between the gradient and the gradient torque TU can be obtained using gradient torque map data 23D that is predetermined.

[0265] The overpass prohibition control of FIG. 33 is executed when the shift is in the R range (reverse) in the same way as when the shift is in the D range.

[0266] 32 , in step S1204, the CPU 21A determines whether the height h of the step ST is higher than a second predetermined height. The second predetermined height is set to a height lower than the first predetermined height, and in this embodiment, is set to 6.5 cm as an example, but is not limited to this. If the height h of the step ST is higher than the second predetermined height, the CPU 21A proceeds to step S1205. If the height h of the step ST is equal to or less than the second predetermined height, the CPU 21A proceeds to step S1208.

[0267] In step S1205, the CPU 21A executes low-speed passing-over control, which is basically the same as the passing-over prohibition control shown in Fig. 33, except for the processing in steps S1300 and S1302.

[0268] First, the target vehicle speed set in step S1300 is different. In the low-speed crossing control, the target vehicle speed is set to, for example, 1 kph, but is not limited to this.

[0269] In step S1302, the step correction torque TL is calculated by the following equation.

[0270] TL=R×Fz×tan(θ)...(18)

[0271] The low-speed crossing control when the shift is in R range (reverse) is the same as when the shift is in D range except for the processing in step S1300 in which the target vehicle speed is set to -1 kph.

[0272] 32 , in step S1206, the CPU 21A sets the step overrun control flag XEX to 1. When the step overrun control flag XEX is 1, this indicates that torque correction using the pedal misapplication protection control torque TO is being executed, i.e., that the step overrun prohibition control of step S1203 or the low speed step overrun control of step S1205 is being executed. On the other hand, when the step overrun control flag XEX is 0, this indicates that torque correction using the pedal misapplication protection control torque TO is not being executed, i.e., that neither the step overrun prohibition control of step S1203 nor the low speed step overrun control of step S1205 is being executed.

[0273] In step S1207, the CPU 21A executes a process for warning the driver. Specifically, for example, a message such as "Please release the pedal and stop the vehicle" may be displayed on the meter or a voice message may be output from the speaker.

[0274] Figure 34 shows the relationship between vehicle speed, step height h, and step-over control. When the vehicle speed is equal to or less than a first speed (1 kph) and the step height h is higher than a first predetermined height, over-running prohibition control is performed. When the vehicle speed is higher than a second speed (9 kph) or the step height h is equal to or less than a second predetermined height, control to overrun the step is performed at the driver's request. When the vehicle speed is equal to or less than 9 kph and the step height h is higher than the second predetermined height but equal to or less than the first predetermined height, or when the vehicle speed is higher than 1 kph but equal to or less than 9 kph and the step height h is higher than the first predetermined height, low-speed over-running control to overrun the step at 1 kph is performed.

[0275] As described above, if the drive control device of the present disclosure detects a locked state when current is supplied to the rotating electric machine, it executes control to suppress the torque of the rotating electric machine so as to lower the temperature of the drive unit (152). For example, by shifting the electrical angle at which current is supplied to a specific phase, the current is distributed among multiple phases included in the rotating electric machine, thereby preventing current from concentrating in a specific phase. Therefore, it is possible to prevent the temperature of a specific phase from becoming excessively high.

[0276] Although the present embodiment has been described above, the present disclosure is not limited to the above-described embodiments, and various modifications and applications are possible within the scope of the gist of the present disclosure.

[0277] Furthermore, the configuration of the vehicle control device 10 described in the above embodiment (see Figure 2) is one example, and it goes without saying that unnecessary parts may be deleted or new parts may be added within the scope of the present disclosure.

[0278] Furthermore, the processing flow of the vehicle control program 23A described in the above embodiment is also an example, and it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged within the scope of the present disclosure.

[0279] The controller and methods described herein may be implemented by a special-purpose computer having a processor programmed to perform one or more functions embodied in a computer program. Alternatively, the apparatus and methods described herein may be implemented by a special-purpose computer having a processor configured with dedicated hardware logic circuitry. Alternatively, the apparatus and methods described herein may be implemented by one or more special-purpose computers configured by a combination of a processor executing a computer program and one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory storage medium.

[0280] The following notes are provided regarding the technology of the present disclosure.

[0281] (Supplementary Note 1) A vehicle control device (10) comprising: an inverter control unit (35) that controls an inverter (151) that drives a rotating electric machine (150) for driving a vehicle (100) mounted on the vehicle; and control units (44, 46) that, when a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine is detected, execute control to suppress the torque of the rotating electric machine so as to lower the temperature when a temperature rise in a drive unit (152) including the rotating electric machine and the inverter is expected.

[0282] (Supplementary Note 2) The vehicle control device according to Supplementary Note 1, wherein the control unit detects the locked state based on at least one of the following: when an accelerator operation amount of the vehicle is greater than a specific value; when it detects that the vehicle has stopped based on the vehicle speed of the vehicle; when it detects that the road load is excessive based on gradient information of the road surface on which the vehicle is traveling or step load estimation information indicating the load when the vehicle goes over a step on the road surface; and when it detects a state in which the vehicle has stopped due to a balance between the torque and the load torque acting on the rotating electric machine, and the torque is greater than a specific value.

[0283] (Supplementary Note 3) The vehicle control device according to Supplementary Note 1 or 2, wherein, when a specific phase of the multiple phases of the rotating electric machine enters a single-phase continuous current state in which current flows continuously for a specific period of time or more during the locked state, the control unit stores the specific phase as a current-carrying phase in the single-phase continuous current state, and when it detects that the specific phase has entered the single-phase continuous current state again, the control unit forcibly shifts the electrical angle at which current is passed to the specific phase so that the current-carrying phase is not the same as the specific phase.

[0284] (Supplementary Note 4) The vehicle control device according to Supplementary Note 3, wherein the control unit changes the electrical angle by a specific amount per specific time period.

[0285] (Supplementary Note 5) The vehicle control device according to Supplementary Note 4, wherein the control unit continues changing the electrical angle until the electrical angle becomes a specific electrical angle obtained by adding a specific value to the stored electrical angle at which current is applied to the specific phase.

[0286] (Supplementary Note 6) The vehicle control device according to Supplementary Note 4, wherein the control unit continues to change the electrical angle until an accelerator pedal of the vehicle is released or until the vehicle goes over a step on a road surface on which the vehicle is traveling.

[0287] (Appendix 7) The vehicle control device according to any one of Appendices 1 to 6, wherein, when the temperature rise is expected, the control unit performs energization control to continuously switch the energized phases among a plurality of phases of the rotating electric machine so that the rotating electric machine continues to rotate at a target rotation speed within a micro-rotation speed range.

[0288] (Supplementary Note 8) The vehicle control device according to Supplementary Note 7, wherein the energization control is speed feedback control that controls the inverter so that the rotating electric machine rotates at a target rotation speed within the minute rotation speed range.

[0289] (Supplementary Note 9) The vehicle control device according to Supplementary Note 8, wherein, when the vehicle is stopped until a specific time has elapsed since the torque suppression started, the control unit cancels the torque suppression and then executes the speed feedback control.

[0290] (Appendix 10) The vehicle control device according to Appendix 7, wherein when the control unit detects an accelerator hill-hold operation in which the vehicle is kept stopped by operating an accelerator pedal provided on the vehicle so that the torque and the load torque acting on the rotating electric machine are balanced, outputs a warning to urge the driver of the vehicle to ease up on the accelerator pedal.

[0291] (Appendix 11) A vehicle control program (23A) that causes at least one processor (21A) to execute processing including: controlling an inverter (151) that drives a rotating electric machine (150) for driving a vehicle (100) that is mounted on the vehicle (100); and, when a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine is detected, executing control to suppress the torque of the rotating electric machine so as to lower the temperature when a temperature rise in a drive unit (152) including the rotating electric machine and the inverter is expected.

[0292] (Appendix 12) A vehicle control method that executes processing including: at least one processor (21A) controls an inverter (151) that drives a rotating electric machine (150) for driving a vehicle (100) mounted on the vehicle; and, when detecting a locked state in which the rotating electric machine does not rotate when current is applied to the rotating electric machine, if a temperature rise in a drive unit (152) including the rotating electric machine and the inverter is expected, executes control to suppress the torque of the rotating electric machine so as to lower the temperature.

Claims

1. An inverter control unit (35) controls an inverter (151) that drives a rotating electric machine (150) for vehicle propulsion mounted on a vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, the control unit (44, 46) executes control to suppress the torque of the rotating electric machine in order to lower the temperature, Equipped with, The control unit, When the aforementioned locked state occurs, if a specific phase among the multiple phases of the rotating electric machine receives continuous current for a specified period of time or longer, the specific phase is stored as the energized phase in the continuous single-phase energized state. When it is detected that the specific phase has again entered the single-phase continuous energized state, the vehicle control device (10) forcibly shifts the electrical angle at which the energized phase is supplied to the specific phase so that the energized phase is not the same as the specific phase.

2. The control unit, If the amount of accelerator operation of the aforementioned vehicle is greater than a specific value, If, based on the vehicle speed of the aforementioned vehicle, it is detected that the vehicle has stopped, If, based on the gradient information of the road surface on which the vehicle is traveling, or the step load estimation information indicating the load when the vehicle overcomes a step on the road surface, it is detected that the road surface load is excessive, and, The system detects that the vehicle has stopped when the torque and the load torque acting on the rotating electric machine are balanced, and if the torque is greater than a certain value, The vehicle control device according to claim 1, which detects the locked state based on at least one of the following.

3. The vehicle control device according to claim 1, wherein the control unit changes the electrical angle by a specific amount of change per specific time period.

4. The vehicle control device according to claim 3, wherein the control unit continues to change the electrical angle until the electrical angle becomes a specific electrical angle obtained by adding a specific value to the electrical angle for which the stored specific phase is energized.

5. The vehicle control device according to claim 3, wherein the control unit continues to change the electrical angle until the vehicle's accelerator is released or until the vehicle overcomes a step on the road surface on which the vehicle is traveling.

6. An inverter control unit (35) that controls an inverter (151) that drives a rotating electric machine (150) for vehicle drive mounted on a vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, the control unit (44, 46) executes control to suppress the torque of the rotating electric machine in order to lower the temperature, Equipped with, The control unit, when a rise in temperature is anticipated, performs energization control by continuously switching the energized phase among the multiple phases of the rotating electric machine so that the rotating electric machine continues to rotate at a target rotation speed within a low rotation speed range.

7. The control unit is If the amount of accelerator operation of the aforementioned vehicle is greater than a specific value, If, based on the vehicle speed of the aforementioned vehicle, it is detected that the vehicle has stopped, If, based on the gradient information of the road surface on which the vehicle is traveling, or the step load estimation information indicating the load when the vehicle overcomes a step on the road surface, it is detected that the road surface load is excessive, and, The system detects that the vehicle has stopped when the torque and the load torque acting on the rotating electric machine are balanced, and if the torque is greater than a certain value, The vehicle control device according to claim 6, which detects the locked state based on at least one of the following.

8. The vehicle control device according to claim 6, wherein the energization control is a speed feedback control that controls the inverter so that the rotating electric machine rotates at a target rotational speed within the low rotational speed range.

9. The vehicle control device according to claim 8, wherein if the vehicle is stopped until a specific time has elapsed since the start of torque suppression, the control unit releases the torque suppression and then performs the speed feedback control.

10. The control unit, When an accelerator hill-hold operation is detected, which involves operating the accelerator pedal on the vehicle to keep the vehicle stationary so that the torque and the load torque acting on the rotating electric machine are balanced, The vehicle control device according to claim 6, which outputs a warning prompting the driver of the vehicle to ease up on pressing the accelerator pedal.

11. At least one processor (21A) Controlling the inverter (151) that drives the rotating electric machine (150) for vehicle propulsion mounted on the vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, control is executed to suppress the torque of the rotating electric machine in order to lower the temperature. When the aforementioned locked state occurs, if a specific phase among the multiple phases of the rotating electric machine receives continuous current for a specified period of time or longer, the specific phase is stored as the energized phase in the continuous single-phase energized state. When it is detected that the specific phase has again entered the single-phase continuous energized state, the electrical angle at which the energized phase is supplied to the specific phase is forcibly shifted so that the energized phase is not the same as the specific phase. A vehicle control program (23A) that causes the system to perform a process that includes the following.

12. At least one processor (21A) Controlling the inverter (151) that drives the rotating electric machine (150) for vehicle propulsion mounted on the vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, control is executed to suppress the torque of the rotating electric machine in order to lower the temperature. If the aforementioned temperature rise is anticipated, the energization control is performed to continuously switch the energized phase among the multiple phases of the rotating electric machine so that the rotating electric machine continues to rotate at a target rotational speed within the low rotational speed range. A vehicle control program (23A) that causes the system to perform a process that includes the following.

13. At least one processor (21A) Controlling the inverter (151) that drives the rotating electric machine (150) for vehicle propulsion mounted on the vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, control is executed to suppress the torque of the rotating electric machine in order to lower the temperature. When the aforementioned locked state occurs, if a specific phase among the multiple phases of the rotating electric machine receives continuous current for a specified period of time or longer, the specific phase is stored as the energized phase in the continuous single-phase energized state. When it is detected that the specific phase has again entered the single-phase continuous energized state, the electrical angle at which the energized phase is supplied to the specific phase is forcibly shifted so that the energized phase is not the same as the specific phase. A vehicle control method that performs a process including the following.

14. At least one processor (21A) Controlling the inverter (151) that drives the rotating electric machine (150) for vehicle propulsion mounted on the vehicle (100), When a locked state is detected in which the rotating electric machine does not rotate when power is supplied to the rotating electric machine, and a rise in temperature of the drive unit (152) including the rotating electric machine and the inverter is expected, control is executed to suppress the torque of the rotating electric machine in order to lower the temperature. If the aforementioned temperature rise is anticipated, the energization control is performed to continuously switch the energized phase among the multiple phases of the rotating electric machine so that the rotating electric machine continues to rotate at a target rotational speed within the low rotational speed range. A vehicle control method that performs a process including the following.