WO2016075812A1

WO2016075812A1 - Drive force control system for electric vehicle, electric vehicle, and rotary electrical machine

Info

Publication number: WO2016075812A1
Application number: PCT/JP2014/080179
Authority: WO
Inventors: 隆明石井; 野中　剛; 荘平大賀; 大戸　基道; 森本　進也
Original assignee: 株式会社安川電機
Priority date: 2014-11-14
Filing date: 2014-11-14
Publication date: 2016-05-19

Abstract

[Problem] To maintain yaw rate behavior even when drive force distribution to wheels has been made to vary in order to avoid loss of motor drive capability. [Solution] A drive force control system Sy of an electric vehicle 1 comprises: motors 3FL-3RR which are configured so as to have varying magnetic field fluxes and which individually drive wheels 2FL-2RR; temperature sensors 6FL-6RR that individually detect the temperatures of the motors 3FL-3RR; a state determination unit 505 that determines whether the thermal states of the motors 3 are suitable on the basis of the temperatures detected by the temperature sensors 6; a command correction unit 506 that, if the state determination unit 505 has determined that the thermal state of one or more of the motors 3 is not suitable, corrects a torque command to said motor 3 towards the reduction side and, in order to maintain the electric vehicle 1 yaw moment in a case where such correction is not performed, the command correction unit corrects the torque commands to the remaining motors 3; and a field control unit 507 that individually controls the magnetic field fluxes of the motors 3FL-3RR on the basis of the torque commands corrected by the command correction unit 506.

Description

Electric vehicle driving force control system, electric vehicle, and rotating electric machine

The disclosed embodiment relates to a driving force control system for an electric vehicle, an electric vehicle, and a rotating electric machine.

Patent Document 1 describes a driving force control device for a left and right wheel independent driving vehicle. This driving force control device gradually reduces the driving force applied to the front wheels on the inner side in the turning direction when the driving source of the front wheels on the outer side in the turning direction becomes incapable of driving when the vehicle is turning. When the power supply is stopped and the driving source of the front wheel on the inner side in the turning direction becomes incapable of driving during the turning of the automobile, the supply of the driving force to the front wheel on the outer side in the turning direction is immediately stopped.

JP-A-8-168112

Although the above-mentioned conventional technology can suppress the unstable running of the vehicle caused by a sudden change in the behavior of the vehicle, it cannot prevent the behavior change of the vehicle itself. For this reason, the yaw rate behavior that is the actual turning traveling state of the vehicle corresponding to the driver's steering operation cannot be maintained, and the straight-running stability before turning into a drive failure, the turning radius, etc. change. There are challenges.

The present invention has been made in view of such problems, and an electric vehicle capable of maintaining the yaw rate behavior even when the driving force distribution of the wheels is changed in order to avoid the inability to drive the motor. An object is to provide a driving force control system, an electric vehicle, and a rotating electric machine.

In order to solve the above problems, according to one aspect of the present invention, there is provided a driving force control system for an electric vehicle that controls the driving force of a plurality of wheels of the electric vehicle, wherein the field magnetic flux is changed. A plurality of motors that individually drive the plurality of wheels, a number of state sensors that individually detect the states of the plurality of motors, and a state of the motor based on a detection result of the state sensors. A first state determination unit that determines whether or not the motor is appropriate; and when the state of any one or more of the plurality of motors is determined to be inappropriate by the first state determination unit, the motor A first command correction unit that corrects torque commands to the remaining motors so as to maintain the yaw moment of the electric vehicle when the correction is not performed and the yaw moment of the electric vehicle when the correction is not performed, Driving force control system for an electric vehicle having a, a first field control unit individually controlling the field flux of the plurality of motors based on the torque command which is corrected by 1 command correction unit is applied.

According to another aspect of the present invention, there is provided a driving force control system for an electric vehicle that controls the driving force of a plurality of wheels of the electric vehicle, the field magnetic flux changing, and the plurality of wheels. A plurality of motors that individually drive the motor, the same number of temperature sensors as the motors that individually detect the temperatures of the motors, and whether or not the thermal state of the motor is appropriate based on the detected temperature of the temperature sensor A second state determination unit that determines whether or not the thermal state of any one or more of the plurality of motors is inappropriate by the second state determination unit. A second command correction unit that corrects torque commands to the remaining motors so that the yaw moment of the electric vehicle is maintained when the torque command is not corrected, and the yaw moment of the electric vehicle is maintained. 2 command supplement A second field control unit individually controlling the field flux of the plurality of motors based on the torque command corrected by section, the driving force control system for an electric vehicle having applied.

Further, according to still another aspect of the present invention, an electric vehicle having a plurality of wheels and the driving force control system is applied.

Further, according to still another aspect of the present invention, there is applied a rotating electrical machine that is provided in the driving force control system of the electric vehicle and configured to change the field magnetic flux.

According to still another aspect of the present invention, there is provided a driving force control system for an electric vehicle that controls the driving force of a plurality of wheels of the electric vehicle, wherein the field magnetic flux is changed, A plurality of motors for individually driving the wheels, and means for changing the driving force distribution of the plurality of wheels while maintaining the yaw moment of the electric vehicle by individually changing the field magnetic flux of the plurality of motors; , A driving force control system for an electric vehicle is applied.

According to still another aspect of the present invention, there is provided a driving force control system for an electric vehicle that controls the driving force of a plurality of wheels of the electric vehicle, wherein the field magnetic flux is changed, A plurality of motors that individually drive the wheels, the same number of temperature sensors that individually detect the temperatures of the plurality of motors, and whether the thermal state of the motor is appropriate based on the detected temperature of the temperature sensor And when it is determined that the thermal state of any one or more of the plurality of motors is not appropriate, the torque command to the motor is corrected to the decrease side, and the The torque commands to the remaining motors are corrected so that the yaw moment of the electric vehicle without correction is maintained, and the field fluxes of the plurality of motors are individually set based on the corrected torque commands. A controller Gosuru, the driving force control system for an electric vehicle having applied.

According to still another aspect of the present invention, there is provided a driving force control method for an electric vehicle that controls the driving force of a plurality of wheels of the electric vehicle, based on a detected temperature of a motor detected by a temperature sensor. A step of determining whether or not a thermal state of the motor is appropriate; and a torque to the motor when it is determined that the thermal state of any one or more of the plurality of motors is not appropriate. Correcting the command to decrease, and correcting the torque command to the remaining motor so that the yaw moment of the electric vehicle when the correction is not made is maintained, and corrected by the command correction unit Individually controlling the field flux of a plurality of motors configured to change field flux based on the torque command and individually driving the plurality of wheels. Driving force control method for a vehicle is applied.

According to still another aspect of the present invention, the controller controls the driving force of the plurality of wheels of the electric vehicle, and the thermal state of the motor is based on the detected temperature of the motor detected by the temperature sensor. A state determination unit that determines whether or not the motor is appropriate; and when the state determination unit determines that the thermal state of any one or more of the plurality of motors is not appropriate, A command correction unit that corrects the torque command to the remaining motor and corrects the torque command to the remaining motor so that the yaw moment of the electric vehicle when the torque command is not corrected is maintained. A field controller configured to individually control the field flux of a plurality of motors configured to change a field flux based on the corrected torque command and individually driving the plurality of wheels. The controller having a applies.

According to the driving force control system for an electric vehicle of the present invention, the yaw rate behavior can be maintained even when the wheel driving force distribution is changed in order to avoid the inability to drive the motor.

1 is a schematic diagram illustrating an example of a schematic configuration of an electric vehicle according to an embodiment. It is an axial sectional view showing an example of the composition of a motor. It is a perspective view showing an example of the state of a rotor when a field magnetic flux is the maximum. It is a perspective view showing an example of the state of a rotor when field magnetic flux is medium. It is a perspective view showing an example of the state of a rotor when a field magnetic flux is the minimum. It is a functional block diagram showing an example of the composition of a controller. It is a table | surface which shows an example of the control numerical map measured value at the time of the maximum efficiency vector control of a motor. It is a table | surface which shows an example of the control numerical map measured value at the time of the maximum efficiency vector control of a motor. It is a table | surface which shows an example of the map with which the data for reproducing the maximum efficiency vector control of a motor were recorded. It is a graph which shows an example of the characteristic of the magnetic field field with respect to the relative angle of two sets of magnetic pole parts of a motor. It is a flowchart showing an example of the driving force control method of an electric vehicle. It is a schematic diagram which represents typically an example of correction | amendment of the torque command performed by step S5 in FIG. It is a schematic diagram which represents typically an example of correction | amendment of the torque command performed by step S7, S9 in FIG. FIG. 11 is a schematic diagram schematically illustrating an example of torque command correction executed in steps S7 and S10 in FIG. 10. It is a time chart which compares and shows an example of the time change of the detected temperature which concerns on each of four motors, and an example of the time change of the torque command to the motor correct | amended by the reduction | decrease side. It is a functional block diagram showing an example of the structure of the controller in the modification which selects and performs a drive mode. It is a schematic diagram showing an example of the drive state of each motor when the front wheel drive mode is selected and executed. It is a schematic diagram which represents typically an example of correction | amendment of a torque command in case the front wheel drive mode is selected and performed. It is a schematic diagram showing an example of the drive state of each motor when the rear wheel drive mode is selected and executed. It is a schematic diagram which represents typically an example of correction | amendment of a torque command when a rear-wheel drive mode is selected and performed. It is a schematic diagram showing an example of the drive state of each motor when the diagonal wheel drive mode is selected and executed. It is a schematic diagram which represents typically an example of correction | amendment of a torque command when the diagonal wheel drive mode is selected and performed.

Hereinafter, an embodiment will be described with reference to the drawings. In the present specification and drawings, components having substantially the same function are represented by the same reference numerals in principle, and repeated description of these components will be omitted as appropriate.

<1. Example of schematic configuration of electric vehicle>
First, an example of a schematic configuration of the electric vehicle according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the electric vehicle 1 is configured to independently drive four wheels 2FL, 2FR, 2RL, and 2RR (hereinafter collectively referred to as “wheel 2” as appropriate) installed in the front, rear, left, and right. This is an electric vehicle (EV) of a four-wheel independent drive system. The wheels 2FL and 2RL are front wheels (front wheels), and the wheels 2RL and 2RR are rear wheels (rear wheels). Specifically, the wheel 2FL is a left front wheel (left front wheel), and the wheel 2RL is a right front wheel (right front wheel). The wheel 2RL is a left rear wheel (left rear wheel), and the wheel 2RR is a right rear wheel (right rear wheel). The electric vehicle 1 includes the wheels 2FL to 2RR and a driving force control system Sy that controls the driving force of the wheels 2FL to 2RR.

Wheels 2FL, 2FR, 2RL, and 2RR are connected to motors 3FL, 3FR, 3RL, and 3RR, which will be described later, via drive shafts 9FL, 9FR, 9RL, and 9RR, respectively.

The driving force control system Sy includes four motors 3FL, 3FR, 3RL, 3RR (corresponding to an example of a rotating electric machine), four temperature sensors 6FL, 6FR, 6RL, 6RR (corresponding to an example of a state sensor), and four Rotational speed sensors 25FL, 25FR, 25RL, and 25RR, a yaw rate sensor 7, a controller 5, and a battery 8 are included. Hereinafter, as appropriate, the motors 3FL to 3RR are collectively referred to as “motor 3”, and the temperature sensors 6FL to 6RR are collectively referred to as “temperature sensor 6”.

The motors 3FL to 3RR are variable field type electric motors configured to change the field magnetic flux. Motors 3FL to 3RR are connected to controller 5 via a power cable and operate based on the power from controller 5. Thus, motors 3FL-3RR individually drive wheels 2FL-2RR. Motors 3FL-3RR can also generate electric power by utilizing the rotation of wheels 2FL-2RR.

The temperature sensors 6FL to 6RR are mounted by, for example, a thermistor, and are respectively provided inside the motors 3FL to 3RR (for example, near the stator windings in the motor frame). Temperature sensors 6FL to 6RR detect the temperatures (examples of states) of motors 3FL to 3RR, respectively. The temperature detected by each of the temperature sensors 6FL to 6RR, that is, the detected temperature (an example of a detection result) is output to the controller 5 via the signal cable.

Rotational speed sensors 25FL to 25RR are provided in the motors 3FL to 3RR, respectively. Rotational speed sensors 25FL to 25RR detect the rotational speeds of motors 3FL to 3RR, respectively. The rotational speed detected by each of the rotational speed sensors 25FL to 25RR is output to the controller 5 via a signal cable.

The rotational speed sensors 25FL to 25RR may be provided outside the motors 3FL to 3RR (for example, the wheels 2FL to 2RR and the drive shafts 9FL to 9RR).

The yaw rate sensor 7 detects the yaw rate of the electric vehicle 1. The yaw rate detected by the yaw rate sensor 7 is output to the controller 5 via a signal cable.

The controller 5 is mounted by, for example, an ECU having an inverter function. The controller 5 converts the DC power from the battery 8 into AC power and supplies it to the motors 3FL to 3RR via the power cable. As a result, the controller 5 controls the motors 3FL to 3RR and controls the driving forces of the wheels 2FL to 2RR. The controller 5 can also charge the battery 8 by converting AC power generated by the motors 3FL to 3RR into DC power.

At this time, the controller 5 changes the driving force distribution of the wheels 2FL to 2RR while maintaining the yaw moment of the electric vehicle 1 by individually changing the field magnetic flux of the motors 3FL to 3RR. That is, the controller 5 corresponds to an example of “means for changing the driving force distribution of the plurality of wheels while maintaining the yaw moment of the electric vehicle by individually changing the field magnetic fluxes of the plurality of motors”.

Specifically, the controller 5 individually controls the field magnetic fluxes of the motors 3FL to 3RR based on torque commands to the motors 3FL to 3RR for realizing the target driving forces of the wheels 2FL to 2RR, respectively.

More specifically, the controller 5 determines whether or not the thermal state of each of the motors 3FL to 3RR is appropriate based on the detected temperature of each of the temperature sensors 6FL to 6RR. When the controller 5 determines that the thermal state of any one or more of the motors 3FL to 3RR is not appropriate, the controller 5 corrects the torque command to the motor 3 to the decrease side, The torque command to the remaining motor 3 is corrected (including correction that does not substantially change) so that the yaw moment of the electric vehicle 1 when the correction is not performed is maintained. Then, the controller 5 individually controls the field magnetic fluxes of the motors 3FL to 3RR based on the corrected torque commands to the motors 3FL to 3RR.

The controller 5 is not limited to individually controlling the field magnetic flux of the motors 3FL to 3RR based on the torque commands to the motors 3FL to 3RR, but based on the speed commands to the motors 3FL to 3RR. The field magnetic flux of motors 3FL-3RR may be individually controlled.

Further, the configuration of the driving force control system 1 of the electric vehicle 1 described above is merely an example, and any configuration other than the above may be used as long as the driving force of the wheels 2FL to 2RR can be controlled. For example, it is not limited to the case where the controller 5 has an inverter function, and an inverter may be provided separately from the controller 5. The controller 5 is not limited to a single device, and may be configured by a plurality of devices.

Further, the configuration of the electric vehicle 1 described above is merely an example, and a configuration other than the above may be used. For example, the driving method of the electric vehicle 1 is not limited to the four-wheel independent driving method, and may be a front wheel independent driving method, a rear wheel independent driving method, or the like. The electric vehicle 1 is not limited to an electric vehicle (EV) driven only by electric power from the battery 8, but is a hybrid electric vehicle (HEV) or plug-in hybrid electric with an external charging function added. It may be an automobile (PHEV), a hydrogen fuel cell automobile (FCV), or the like. Moreover, the number of the wheels 2 of the electric vehicle 1 is not limited to four, and may be another number.

<2. Example of motor configuration>
Next, an example of the configuration of the motors 3FL to 3RR will be described with reference to FIGS. Here, an example of the configuration of the motor 3FL among the motors 3FL to 3RR will be described as a representative example, but the configurations of the other motors 3FR to 3RR can be equivalent to the configuration of the motor 3FL.

As shown in FIG. 2, the motor 3FL outputs the driving force of the wheel 2FL by rotating the shaft 34 connected to the drive shaft 9FL. In this specification, the driving force output side (right side in FIG. 2) by the motor 3FL is referred to as “load side”, and the opposite side (left side in FIG. 2) is referred to as “anti-load side”.

The motor 3FL includes the shaft 34, a rotor 30 provided outside the shaft 34, a stator 10 provided outside the stator 30, a frame 17 provided outside the stator 10, and a frame 17 includes a bracket 16 provided on the load side, a control motor 49 (see FIG. 1), a sensor magnet 20, and the rotational speed sensor 25FL.

The shaft 34 is rotatably supported by a load-side bearing 18 installed on the bracket 16 and an anti-load-side bearing 19 installed on the non-load side of the frame 17. The frame 17 is fastened to the bracket 16 with bolts 11. The sensor magnet 20 is provided on the side surface of the rotor 30 on the side opposite to the load. The rotational speed sensor 25FL is provided facing the sensor magnet 20 in the frame 17, and detects the rotational speed of the rotor 30 as the rotational speed of the motor 3FL.

The rotational speed sensor 25FL may detect the rotational position and acceleration of the rotor 30 instead of or in addition to the rotational speed of the rotor 30 (the same applies to the other rotational speed sensors 25FR to 25RR). Further, the rotational speed sensor 25FL is not limited to a sensor that magnetically detects the rotational speed of the rotor 30, and may be a sensor that optically detects the rotational speed of the rotor 30. (The same applies to the other rotational speed sensors 25FR to 25RR).

The stator 10 includes a stator winding 12 and a stator core 13. The stator winding 12 is attached to the stator core 13. The stator core 13 is fastened to the bracket 16 by bolts 14. A connection portion 21 is provided on the side opposite to the load of the stator 10.

The rotor 30 is configured such that a plurality of magnetic pole portions (details will be described later) provided with field magnets (details will be described later) are divided into two sets (fixed side and movable side) and relatively rotated. ing.

The control motor 49 is provided, for example, outside the anti-load side of the frame 17 and can change the field magnetic flux by relatively rotating the two sets of magnetic pole portions of the rotor 30.

(2-1. Example of rotor configuration)
Hereinafter, an example of the configuration of the rotor 30 will be described with reference to FIGS. 2 and 3.

As shown in FIGS. 2 and 3, the rotor 30 is divided into three parts in the axial direction, and the three parts thus divided are relatively rotated. Specifically, the rotor 30 includes a movable rotor 60 and two fixed

rotors

50 and 50 disposed adjacent to both sides in the axial direction of the movable rotor 60, and is movable by the control motor 49. The rotor 60 is structured to be rotated with respect to the fixed

rotors

50 and 50. The fixed

rotors

50 and 50 are fixed to the shaft 34 by bolts 35 via the load side plate 31 and the anti-load side plate 33.

That is, when the control motor 49 rotates the worm gear 27, the gear wheel 23 rotates and the feed male screw 42 moves in the axial direction with respect to the feed screw 43. A movable bearing 40 is attached to the load side end of the feed male screw 42 to move the pin 36 and the pin holder 28 in the axial direction while blocking the rotation of the rotor 30. The pin 36 moves the slider 37 outside the shaft 34 in the axial direction. Since the outer side of the slider 37 is engaged with the hub 32 by a torsion spline, when the slider 37 moves in the axial direction, the hub 32 and the movable rotor 60 engaged therewith are fixed to the fixed

rotors

50 and 50. Rotate against. O-rings 15 are mounted on both sides of the hub 32 to prevent the filled grease from scattering.

The gear wheel 23 is covered with a cover 24 and is rotatably supported by a bearing 26. The feed male screw 42 and the feed screw 43 are, for example, trapezoidal threaded. Since the feed male screw 42 has a hexagonal hole and engages with the hexagonal shaft 23a of the gear wheel 23, rotation is transmitted so as to be movable in the axial direction. For example, two angular bearings are used face-to-face as the movable bearing 40 attached to the feed male screw 42 and are fixed by a bearing holder 44 and a bolt 45. For example, two angular bearings are used facing each other and fixed to the fixed bearing 41 attached to the feed screw 43 by a nut 29.

The fixed rotor 50 includes an annular first iron core 51 and a plurality of first permanent magnets 52 (corresponding to an example of a field magnet) embedded in the first iron core 51 in the axial direction. The plurality of first permanent magnets 52 is a mode in which two first permanent magnets 52 with the same polarity facing each other form a V-shaped pair projecting radially inward, and the opposing magnetic poles are alternately varied in the circumferential direction. The first iron core 51 is disposed. Thereby, a plurality of magnetic pole portions 53 (hereinafter also referred to as “first magnetic pole portions 53”) having different polarities in the circumferential direction of the fixed rotor 50 are formed.

The movable rotor 60 is rotatable with respect to the shaft 34. The movable rotor 60 includes an annular second iron core 61 and a plurality of second permanent magnets (not shown) (corresponding to an example of field magnets) embedded in the axial direction of the second iron core 61. The plurality of second permanent magnets is a mode in which two second permanent magnets with the same polarity facing each other form a V-shaped pair projecting radially inward, and the opposing magnetic poles are alternately varied in the circumferential direction. Two iron cores 61 are arranged. Thereby, a plurality of N pole and S pole magnetic pole parts 63 (hereinafter also referred to as “second magnetic pole parts 63”) having different polarities alternately are formed in the circumferential direction of the movable rotor 60.

(2-2. Example of change in rotor field magnetic flux)
Hereinafter, an example of changes in the field magnetic flux of the rotor 30 will be described with reference to FIGS.

FIG. 3 corresponds to an example of the state of the rotor 30 when the field magnetic flux is maximum. At this time, the magnetic pole portions of the same polarity of each fixed rotor 50 and the movable rotor 60, that is, the first magnetic pole portion 53 of the N pole (S pole) of each fixed rotor 50 and the N pole (S of the movable rotor 60). The second magnetic pole portion 63 of the pole is aligned in the axial direction (the relative angle is 0 degree in electrical angle). Thereby, the field magnetic flux by the 1st permanent magnet 52 of each fixed rotor 50 and the 2nd permanent magnet of the movable rotor 60 will be in the maximum state.

FIG. 4 corresponds to an example of the state of the rotor 30 when the field magnetic flux is medium. At this time, the movable rotor 60 rotates relative to the fixed

rotors

50 and 50. The first magnetic pole portion 53 of each fixed rotor 50 and the second magnetic pole portion 63 of the movable rotor 60 are the same polarity as the first magnetic pole portion 53 of the N pole (S pole) and the N pole (S pole). The second magnetic pole portion 63 is aligned in the axial direction, and the first magnetic pole portion 53 of N pole (S pole) and the second magnetic pole portion 63 of S pole (N pole) having different polarities are aligned in the axial direction. It is in an intermediate state with the state. Accordingly, the field magnetic flux generated by the first permanent magnet 52 of each fixed rotor 50 and the second permanent magnet of the movable rotor 60 is in an intermediate state.

FIG. 5 corresponds to an example of the state of the rotor 30 when the field magnetic flux is minimum. At this time, the magnetic pole portions having different polarities between the fixed rotor 50 and the movable rotor 60, that is, the first magnetic pole portion 53 of the N pole (S pole) of each fixed rotor 50 and the S pole (N of the movable rotor 60). The second magnetic pole portion 63 of the pole is aligned in the axial direction (the relative angle is 180 degrees in terms of electrical angle). Thereby, the field magnetic flux by the 1st permanent magnet 52 of each fixed rotor 50 and the 2nd permanent magnet of the movable rotor 60 is the 1st iron core 51 of each fixed rotor 50, and the 2nd iron core of the movable rotor 60. Short-circuit with 61 and become the minimum state. As a result, the iron loss generated in the rotor 30 can be sufficiently reduced, and the motor 3FL can operate with high efficiency even in the high rotation operation region.

As described above, the field magnetic flux (induced voltage) becomes maximum when the

magnetic pole portions

53 and 63 having the same polarity are aligned in the axial direction, and the field magnetic flux (when the

magnetic pole portions

53 and 63 having different polarities are aligned in the axial direction. (Induced voltage) is minimized. The ratio of the current induced voltage to the maximum induced voltage, that is, the state in which the

magnetic pole parts

53 and 63 are relatively rotated with respect to the induced voltage constant in the state where the

magnetic pole parts

53 and 63 having the same polarity are aligned and the magnetic field is strongest. The ratio of the induced voltage constant in is referred to as “field susceptibility”.

Note that the configuration of the motor 3FL described above is merely an example, and any configuration other than the above may be used as long as the field magnetic flux changes (the same applies to the other motors 3FR to 3RR). For example, the

magnetic pole portions

53 and 54 of the rotor 30 are not limited to being relatively rotated by the control motor 49, and may be relatively rotated by hydraulic control or the like. Further, the number of divisions of the rotor 30 in the axial direction is not limited to 3, and may be other numbers. Alternatively, the rotor 30 may not be divided.

<3. Example of controller configuration>
Next, with reference to FIG. 6, an example of the configuration of the controller 5 that is specifically implemented with functional blocks will be described.

As shown in FIG. 6, the controller 5 includes a torque control unit 501, a torque determination unit 502, a temperature estimation unit 503, a temperature determination unit 504, and a state determination unit 505 (first state determination unit and second state determination). A command correction unit 506 (corresponding to an example of a first command correction unit and a second command correction unit), a field control unit 507 (corresponding to an example of a first field control unit and a second field control unit), and The map recording unit 508 and the inverter unit 509 are included. Each functional unit of the controller 5 can be implemented by a program executed by a CPU (not shown) provided in the controller 5 or a control device (not shown) provided in the controller 5. The control device is configured by a dedicated integrated circuit or other electrical circuit constructed for a specific application such as ASIC or FPGA.

The torque control unit 501 generates a torque command to each of the motors 3FL to 3RR based on, for example, the opening degree of an accelerator pedal (not shown), the vehicle speed, and the like.

Based on the maximum torque of the motor 3, the torque determination unit 502 corrects the torque command to the motor 3 generated by the torque control unit 501. It is determined whether or not the total torque command when the torque command is not corrected can be maintained. Note that the maximum torque of the motor 3 is recorded in the controller 5 in advance.

The temperature estimation unit 503 estimates the temperature of the motor 3 after detection based on the temperature detected by the temperature sensor 6 or the like. Specifically, the temperature estimation unit 503 calculates the change amount of the detected temperature per unit time of the temperature sensor 6 related to the motor 3, and estimates the temperature of the motor 3 after a predetermined time based on the calculated change amount. To do.

As described later, the temperature determination unit 504 is based on the detected temperature of the temperature sensor 6 related to the motor 3 corrected by the command correction unit 506 so that the torque command is reduced, and the detected temperature related to the motor 3 is the upper limit of the allowable temperature range. It is determined whether or not the value is below. The allowable temperature range is a temperature range in which the motor 3 can operate so as not to cause a thermal failure (for example, seizure or the like). The upper limit value of the allowable temperature range is higher than the upper limit value of the recommended temperature range described later. The allowable temperature range is recorded in the controller 5 in advance.

The state determination unit 505 determines whether the thermal state of the motor 3 is appropriate based on the temperature detected by the temperature sensor 6. At this time, the state determination unit 505 determines whether or not the detected temperature related to one or more of the motors 3FL to 3RR exceeds the recommended temperature range based on the detected temperatures of the temperature sensors 6FL to 6RR. judge. The recommended temperature range is an ideal temperature range for the motor 3 to operate. The recommended temperature range is recorded in the controller 5 in advance. The state determination unit 505 drives the motor 3 in response to the torque command to the motor 3 generated by the torque control unit 501 based on the temperature of the motor 3 estimated by the temperature estimation unit 503, that is, the estimated temperature. When it does, it determines whether the said estimated temperature exceeds an allowable temperature range. The state determination unit 505 determines that the thermal state of the motor 3 is not appropriate when the temperature estimated by the temperature estimation unit 503 exceeds the allowable temperature range. The upper limit value of the allowable temperature range is not particularly limited, but is set to 150 degrees, for example.

The command correction unit 506 reduces the torque command to the motor 3 when the state determination unit 505 determines that the thermal state of any one or more of the motors 3FL to 3RR is not appropriate. And the torque command to the remaining motor 3 is corrected so that the yaw moment of the electric vehicle 1 when the correction is not performed is maintained.

At this time, the command correction unit 506 calculates the total torque command when the torque command to the motor 3 is not corrected by the torque determination unit 502 when the torque command to the motor 3 is corrected. If it is determined that the torque can be maintained, the torque commands to the remaining motors 3 are corrected so that the total torque command is maintained. On the other hand, the command correction unit 506 maintains the total torque command when the torque command to the motor 3 is not corrected by the torque determination unit 502 when the torque command to the motor 3 is corrected. If it is determined that it is not possible, among the remaining motors 3, the torque command to the motor 3 located on the opposite side of the motor 3, which has been corrected to the decrease side in the width direction of the electric vehicle 1, is reduced. to correct.

In addition, when the temperature determination unit 504 determines that the detected temperature of the motor 3 that has corrected the torque command to the decrease side is lower than the upper limit value of the allowable temperature range, the command correction unit 506 outputs the torque command of the motor 3. Restore gradually.

The command correction unit 506 may finely adjust the correction of the torque command by feedback control based on the yaw rate detected by the yaw rate sensor 7. In this case, the maintenance accuracy of the yaw rate behavior of the electric vehicle 1 can be increased.

The field control unit 507 individually controls the field magnetic fluxes of the motors 3FL to 3RR based on the torque commands to the motors 3FL to 3RR corrected by the command correction unit 506. At this time, the field controller 507 controls the control motor 49 of each of the motors 3FL to 3RR based on the corrected torque command to each of the motors 3FL to 3RR, so that the field magnetic flux of the motors 3FL to 3RR is obtained. Control individually.

More specifically, the field control unit 507 determines a map (not shown) based on the rotation speed detected by each of the rotation speed sensors 25FL to 25RR and the torque command to each of the corrected motors 3FL to 3RR. The map control for reading data with reference to is performed. The map is recorded in advance in the map recording unit 508. The data read out by the field control unit 507 is the phase angle of the current supplied to the stator winding 12 with respect to the target value of the magnetic field factor and the magnetic pole position generated by the combination of the

magnetic pole parts

53 and 63 for each of the motors 3FL to 3RR. And the target value of the magnitude of the current. As the phase angle of the current increases, the rotational electromagnetic force generated by the stator 10 with respect to the magnetic poles of the rotor 30 advances and the field weakening strength increases.

FIGS. 7A and 7B show an example of control numerical value map measurement values at the time of maximum efficiency vector control of the motor 3FL. FIG. 7A shows an example of the above-described field ratio, with the horizontal axis representing the rotational speed of the motor 3FL and the vertical axis representing the torque command during the maximum efficiency vector control of the motor 3FL. FIG. 7B shows an example of the phase angle of the current with the horizontal axis representing the rotational speed of the motor 3FL and the vertical axis representing the torque command during the maximum efficiency vector control of the motor 3FL.

In the example shown in FIGS. 7A and 7B, the field ratio is decreased as the rotation speed of the motor 3FL is increased, and is decreased as the torque command is decreased, and the phase angle of the current is increased as the rotation speed of the motor 3FL is increased. Moreover, the efficiency of the motor 3FL can be maximized by increasing the torque command as it is higher. For example, when the rotation speed of the motor 3FL is 16000 rev / min and the torque command is 70%, the relative angle of the

magnetic pole portions

53 and 63 is adjusted so that the field ratio is 69%, and the phase angle of the current is set. By energizing the stator winding 12 at 78 °, the efficiency of the motor 3FL can be maximized.

FIG. 8 shows an example of a map in which data for reproducing the maximum efficiency vector control of the motor 3FL is recorded. In FIG. 8, the horizontal axis represents the rotational speed of the motor 3FL and the vertical axis represents the torque command, and the field at which the field ratio, the current phase angle, and the magnitude of the current were recorded during the maximum efficiency vector control of the motor 3FL. An example is shown.

In the example shown in FIG. 8, for example, when the rotational speed of the motor 3FL is between Nm and Nm + 1 and the torque command is between Tn and Tn + 1, data is read from the location of Dmn. In the place of Dmn, data of a field factor αmn, a current phase angle βmn, and a current magnitude Imn are recorded. In the map, for example, data for all rotation speeds and torque commands at which the motor 3FL is operated is recorded.

As shown in FIG. 6, the field control unit 507 determines the corresponding location of the map based on the rotational speed detected by each of the rotational speed sensors 25FL to 25RR and the torque command to each of the corrected motors 3FL to 3RR. Are read as the target values of the magnetic field ratio, current phase angle, and current magnitude related to each of the motors 3FL to 3RR. Then, the field control unit 507 supplies the read electric power for realizing the target values of the magnetic fields related to the motors 3FL to 3RR to the control motors 49 of the motors 3FL to 3RR. , 63 are adjusted to individually control the field magnetic fluxes of the motors 3FL to 3RR.

FIG. 9 shows an example of the magnetic field characteristics with respect to the relative angles of the

magnetic pole portions

53 and 63 of the motor 3FL. In FIG. 9, the relative angle of the

magnetic pole portions

53 and 63 of the motor 3FL is taken on the horizontal axis, and the magnetic field ratio is taken on the vertical axis. In this case, an example of the magnetic field characteristics with respect to the relative angles of the

magnetic pole portions

53 and 63 is shown. In the example shown in FIG. 9, it is shown that the field ratio can be changed from 100% to 30% by changing the relative angle of the

magnetic pole portions

53 and 63 from 0 ° to 120 °.

As shown in FIG. 6, the inverter unit 509 converts the DC power from the battery 8 into AC power based on torque commands to the motors 3FL to 3RR, and the stator windings 12 of the motors 3FL to 3RR. To supply power. Thus, inverter unit 509 drives each of motors 3FL to 3RR. At this time, the inverter unit 509 converts the DC power from the battery 8 to AC based on the target value of the current phase angle and the target value of the magnitude of the current related to each of the motors 3FL to 3RR read by the field control unit 507. The electric power is converted into electric power, and electric power is supplied to the stator windings 12 of the motors 3FL to 3RR.

The configuration of the controller 5 described above is merely an example, and the driving force distribution of the wheels 2FL to 2RR is maintained while maintaining the yaw moment of the electric vehicle 1 by individually changing the field magnetic flux of the motors 3FL to 3RR. Any configuration other than the above may be used as long as the configuration can be changed. For example, the processing content of each functional unit of the controller 5 is not limited to the content described above, and may be other content. Further, the separation of each functional unit of the controller 5 is not limited to the separation described above, and may be other than the above.

<4. Example of driving force control method for electric vehicle>
Next, an example of a driving force control method for the electric vehicle 1 using the controller 5 will be described with reference to FIG.

As shown in FIG. 10, first in step S0, the torque control unit 501 generates a torque command to each of the motors 3FL to 3RR based on, for example, the opening degree of the accelerator pedal, the vehicle speed, and the like.

Thereafter, in step S1, the controller 5 acquires the detected temperatures of the temperature sensors 6FL to 6RR.

In step S2, state determination unit 505 determines whether the detected temperature related to one or more of motors 3FL to 3RR exceeds the recommended temperature range based on the detected temperatures of temperature sensors 6FL to 6RR. Determine whether or not. If the detected temperature related to any motor 3 does not exceed the recommended temperature range, the determination in step S2 is not satisfied, and the detected temperature of any temperature sensor 6 is sufficiently lower than the upper limit value of the allowable temperature range. The motor 3 is also regarded as having no risk of thermal failure, and the process proceeds to step S3.

In step S3, the command correction unit 506 outputs the torque command to each of the motors 3FL to 3RR to the inverter unit 509 via the field control unit 507 without correcting the torque command.

In step S31, inverter unit 509 converts DC power from battery 8 into AC power based on torque commands from command correction unit 506 to motors 3FL to 3RR, and fixes motors 3FL to 3RR. By supplying electric power to the child winding 12, each of the motors 3FL to 3RR is driven. Thereafter, the processing shown in this flowchart is terminated.

On the other hand, if the detected temperature related to one or more motors 3 exceeds the recommended temperature range in step S2, the determination in step S2 is satisfied, and the process proceeds to step S4.

In step S21, the temperature estimation unit 503 calculates the amount of change in the detected temperature per unit time of the temperature sensor 6 related to the motor 3 whose detected temperature exceeds the recommended temperature range. For example, the temperature estimation unit 503 changes between the detected temperature related to the motor 3 acquired in step S1 when the previous flowchart is executed and the detected temperature related to the motor 3 acquired in step S1 when the current flowchart is executed. A temperature change rate (rate of increase) obtained by dividing the amount by the flowchart execution time is calculated. And the temperature estimation part 503 estimates the temperature which concerns on the said motor 3 after predetermined time based on the calculated temperature change rate.

Thereafter, in step S4, the state determination unit 505 determines, based on the estimated temperature of the temperature estimation unit 503, the motor 3 whose detected temperature exceeds the recommended temperature range, which is generated in step S0. In the case of driving corresponding to the above, it is determined whether or not the estimated temperature exceeds the allowable temperature range. The estimated temperature of the motor 3 corresponding to the front wheel 2 (hereinafter also referred to as “front wheel motor 3”) and the motor 3 corresponding to the rear wheel 2 (hereinafter also referred to as “rear wheel motor 3”). If both the estimated temperatures exceed the allowable temperature range, the process proceeds to step S5.

In step S5, the command correction unit 506 corrects the torque commands to the motors 3FL to 3RR to the decreasing side at a uniform rate.

In step S51, the inverter unit 509 converts the DC power from the battery 8 into AC power based on the torque command to each of the motors 3FL to 3RR corrected in step S5, and each of the motors 3FL to 3RR. Power is supplied to the stator winding 12. Thus, inverter unit 509 drives each of motors 3FL to 3RR. Thereafter, the processing shown in this flowchart is terminated.

FIG. 11 is a schematic diagram schematically showing an example of torque command correction executed in step S5. In the example shown in FIG. 11, the torque command to each of the motors 3FL to 3RR is corrected to the decreasing side at a uniform rate in step S5.

As shown in FIG. 10, in step S4, when one of the estimated temperature related to the front wheel motor 3 and the estimated temperature related to the rear wheel motor 3 exceeds the allowable temperature range, the process proceeds to step S6.

In step S6, the controller 5 determines whether the motor 3 whose estimated temperature exceeds the allowable temperature range is the front wheel motor 3 or the rear wheel motor 3. When the motor 3 whose estimated temperature exceeds the allowable temperature range is the front wheel motor 3, the determination in step S6 is satisfied, and the process proceeds to step S7.

In step S7, the command correction unit 506 corrects the torque command to at least one front wheel motor 3 of which the estimated temperature exceeds the allowable temperature range among the front wheel motors 3FL and 3FR to the decrease side by a predetermined value α.

Thereafter, in step S8, the torque determination unit 502 sums the torque commands to all the motors 3 when the torque commands to the rear wheel motors 3RL and 3RR are corrected based on the maximum torque of the rear wheel motors 3RL and 3RR. Is calculated. Then, torque determination unit 502 calculates the difference between the calculated total torque command and the total torque command when the torque commands to rear wheel motors 3RL and 3RR are not corrected. Based on the calculated difference, the torque determination unit 502 determines whether or not the total torque command when the torque command is corrected can maintain the total torque command when the torque command is not corrected, that is, the rear wheel. It is determined whether or not the torque command to the motors 3RL and 3RR can be corrected to the increase side by the predetermined value α. When the torque command is corrected, the sum of the torque commands can maintain the sum of the torque commands when the torque command is not corrected, that is, the torque commands to the rear wheel motors 3RL and 3RR can be corrected to an increase side by a predetermined value α. If YES, the determination at step S8 is satisfied, and the routine goes to step S9.

In step S9, the command correction unit 506 is a rear wheel located on the same side of the rear wheel motors 3RL, 3RR as the front wheel motor 3 in which the torque command is corrected to the reduction side in step S7 in the width direction of the electric vehicle 1. The torque command to the motor 3 is corrected to the increase side by a predetermined value α. As a result, the total torque command when the torque command to the rear wheel motor 3 is corrected is maintained as the total torque command when the torque command to the rear wheel motor 3 is not corrected. Thereafter, the process proceeds to step S141 described later. When the torque command to each of the front wheel motors 3FL and 3FR is corrected to the decrease side in step S7, the torque command to each of the rear wheel motors 3RL and 3RR is corrected to the increase side in this step S9. .

FIG. 12 is a schematic diagram schematically showing an example of torque command correction executed in steps S7 and S9. In the example shown in FIG. 12, the torque command to the front wheel motor 3FL is corrected to the decrease side in step S7, and the torque command to the rear wheel motor 3RL is corrected to the increase side in step S9.

On the other hand, in step S8, the sum of the torque commands when the torque command is corrected cannot maintain the sum of the torque commands when the torque command is not corrected, that is, the torque commands to the rear wheel motors 3RL and 3RR are set to a predetermined value α. If correction cannot be made to the increase side, the determination in step S8 is not satisfied, and the routine goes to step S10.

In step S10, the command correction unit 506 is located on the opposite side of the rear wheel motors 3RL, 3RR on the side opposite to the front wheel motor 3 in which the torque command is corrected to the decrease side in step S7 in the width direction of the electric vehicle 1. The torque command to the motor 3 is corrected to the decrease side by a predetermined value α. Thereafter, the process proceeds to step S141 described later.

FIG. 13 is a schematic diagram schematically showing an example of torque command correction executed in steps S7 and S10. In the example shown in FIG. 13, the torque command to the front wheel motor 3FL is corrected to the decrease side in step S7, and the torque command to the rear wheel motor 3RR is corrected to the decrease side in step S10.

On the other hand, when the motor 3 whose estimated temperature exceeds the allowable temperature range is the rear wheel motor 3 in step S6, the determination in step S6 is not satisfied, and the process proceeds to step S11.

In step S11, the command correction unit 506 corrects the torque command to at least one of the rear wheel motors 3RL, 3RR, which has an estimated temperature exceeding the allowable temperature range, to the decrease side by a predetermined value α.

In step S12, the torque determination unit 502 calculates the sum of the torque commands to all the motors 3 when the torque commands to the front wheel motors 3LL and 3LR are corrected based on the maximum torque of the front wheel motors 3LL and 3LR. To do. Then, the torque determination unit 502 calculates a difference between the calculated sum of the torque commands and the sum of the torque commands when the torque commands to the front wheel motors 3LL and 3LR are not corrected. Based on the calculated difference, the torque determination unit 502 determines whether the total torque command when the torque command is corrected can maintain the total torque command when the torque command is not corrected, that is, the front wheel motor. It is determined whether the torque command to 3LL and 3LR can be corrected to the increase side by the predetermined value α. When the torque command is corrected, the total torque command when the torque command is not corrected can be maintained. That is, the torque command to the front wheel motors 3LL and 3LR can be corrected to an increase side by a predetermined value α. If there is, the determination at step S12 is satisfied, and the routine goes to step S13.

In step S13, the command correction unit 506 is a front wheel motor located on the same side of the front wheel motors 3LL and 3LR as the rear wheel motor 3 in which the torque command is corrected to decrease in the width direction of the electric vehicle 1 in step S11. 3 is corrected to the increase side by a predetermined value α. As a result, the total torque command when the torque command to the front wheel motor 3 is corrected is maintained as the total torque command when the torque command to the front wheel motor 3 is not corrected. Thereafter, the process proceeds to step S141 described later. If the torque command to each of the rear wheel motors 3RL and 3RR is corrected to the decrease side in step S11, the torque command to each of the front wheel motors 3LL and 3LR is corrected to the increase side in this step S13. .

On the other hand, when the torque command is corrected in step S12, the total torque command when the torque command is not corrected cannot be maintained. That is, the torque command to the front wheel motors 3LL and 3LR is set to the predetermined value α. If correction cannot be made on the increase side, the determination in step S12 is not satisfied, and the routine goes to step S14.

In step S14, the command correction unit 506 is a front wheel motor located on the opposite side of the front wheel motors 3LL, 3LR in the width direction of the electric vehicle 1 from the rear wheel motor 3 in which the torque command is corrected to the decrease side in step S11. 3 is corrected to the decrease side by a predetermined value α. Thereafter, the process proceeds to step S141.

In step S141, the field control unit 507 determines the rotational speed detected by each of the rotational speed sensors 25FL to 25RR and the torque command to each of the motors 3FL to 3RR corrected in any of the above steps S9, S10, S13, and S14. Based on the above, the aforementioned map control is performed. That is, the field control unit 507 reads out the magnetic field ratio, current phase angle, and current magnitude data relating to each of the motors 3FL to 3RR recorded at the corresponding locations in the map as their target values. Then, the field control unit 507 supplies the read electric power for realizing the target values of the magnetic fields related to the motors 3FL to 3RR to the control motors 49 of the motors 3FL to 3RR. By adjusting the relative angle of 63, the field magnetic fluxes of the motors 3FL to 3RR are individually controlled.

Thereafter, in step S142, the inverter unit 509 causes the direct current from the battery 8 based on the target value of the current phase angle and the target value of the current magnitude related to each of the motors 3FL to 3RR read in step S141. The electric power is converted into AC power, and the electric power is supplied to the stator windings 12 of the motors 3FL to 3RR. Thus, inverter unit 509 drives each of motors 3FL to 3RR.

In step S15, the controller 5 acquires the detected temperatures of the temperature sensors 6FL to 6RR.

Thereafter, in step S16, the temperature determination unit 504 determines the motor 3 based on the detected temperature of the temperature sensor 6 related to the motor 3 in which the torque command is corrected to the decrease side in any one of the steps S7 and S11. It is determined whether or not the detected temperature related to is lower than the upper limit value of the allowable temperature range. If the detected temperatures for all the motors 3 whose torque commands have been corrected to decrease are not lower than the upper limit value of the recommended temperature range, the determination in step S16 is not satisfied, and step S17 described later is skipped. The process shown in the flowchart is terminated. . On the other hand, if the detected temperature for all the motors 3 whose torque command has been corrected to decrease is below the upper limit value of the recommended temperature range, the determination in step S16 is satisfied, and the routine proceeds to step S17.

In step S17, the command correction unit 506 outputs torque commands to all the motors 3FL to 3RR including all the motors 3 in which the torque command has been corrected to the decrease side in any one of the steps S7 and S11. It is gradually restored so that it matches the torque command when no correction is made. Thereafter, the processing shown in this flowchart is terminated. The process shown in this flowchart is repeatedly executed.

In addition, the content of the driving force control method of the electric vehicle 1 demonstrated above is an example to the last, and may be another content. For example, the steps described in the flowchart shown in FIG. 10 are executed in parallel or individually even if they are not necessarily processed in time series, as well as processes performed in time series in the order described. Processing. Even in the steps processed in time series, the order can be appropriately changed depending on circumstances.

FIG. 14 shows a comparison between an example of the change over time of the detected temperature associated with each of the motors 3FL to 3RR and an example of the change over time of the torque command to the motor 3 corrected to the decrease side.

In the example shown in FIG. 14, when the detected temperature related to one of the motors 3FL to 3RR exceeds the recommended temperature range at time t1, the change in detected temperature from time t1 related to the motor 3 to after time Δt. The subsequent temperature of the motor 3 is estimated based on the amount. At this time, if the estimated temperature of the motor 3 exceeds the allowable temperature range, the torque command to the motor 3 is corrected to the decreasing side at time D1 from time t2 to time t3. The torque command to the motor 3 is continuously corrected to decrease after time t3. However, when the detected temperature related to the motor 3 falls below the upper limit value of the recommended temperature range at time t4, the time from time t4 to time t5 is corrected. The time is gradually recovered so as to coincide with the torque command when no correction is made over time D2. Note that D1 <D2.

In the above description, the description of the remaining three motors 3 other than the one of the motors 3FL to 3RR whose detected temperature exceeds the recommended temperature range is omitted.

<5. Examples of effects according to this embodiment>
As described above, in this embodiment, when the command correction unit 506 corrects the torque command to the motor 3 whose thermal state is not appropriate to the decrease side, the yaw moment of the electric vehicle 1 is maintained. Torque commands to the remaining motors 3 are corrected. As a result, it is possible to avoid a thermal malfunction (burn-in, etc.) of the motor 3, and to suppress a change in the yaw moment accompanying a change in the driving force distribution of the wheels 2FL to 2RR and maintain the yaw rate behavior. As a result, for example, even when the torque command is corrected during straight traveling, straight travel performance is not impaired, and even when the torque command is corrected during turning, the turning characteristics can be maintained. it can.

In this embodiment, the field control unit 507 individually controls the field magnetic fluxes of the motors 3FL to 3RR based on the torque command corrected by the command correction unit 506. Since the torque applied to the wheel 2 is controlled by changing the field magnetic flux of the motor 3, the motor 3 can be driven with high efficiency in a wide torque range from low torque to high torque, as compared with the motor 3 in which the field magnetic flux is fixed. it can. Further, the motor 3 whose torque command is corrected to the decrease side is controlled so that the field magnetic flux decreases. Therefore, the iron loss can be reduced, and the copper loss can be reduced by improving the efficiency and reducing the armature current by not using (or reducing) the so-called field weakening current. As a result, the amount of heat generation can be reduced, and the temperature management of the motor 3 is facilitated.

Further, in this embodiment, in particular, the motor 3 relatively rotates the rotor 30 configured so that the

magnetic pole portions

53 and 63 are relatively rotated by being divided into two sets, and the

magnetic pole portions

53 and 63. And a control motor 49. Further, the field control unit 507 controls the field magnetic flux of the motor 3 by controlling the control motor 49 based on the torque command. With such a structure, the field magnetic flux can be accurately controlled regardless of the load torque and rotation speed of the motor 3.

In the present embodiment, in particular, the field control unit 507 determines the target value of the magnetic field, the target value of the phase angle of the current, and the target value of the current phase angle based on the rotational speed of the motor 3 detected by the rotational speed sensor 25 and the torque command. Map control is performed to read out the target value of the magnitude of the current with reference to the map. By such map control, the field magnetic flux of the motor 3 can be finely adjusted according to the rotation speed and the torque command, so that highly accurate torque control can be executed for each wheel 2.

In this embodiment, in particular, the torque determination unit 502 can maintain the torque command sum when the torque command is corrected based on the maximum torque of the motor 3 and the torque command sum when the torque command is not corrected. It is determined whether or not. Then, when the command correction unit 506 determines that the torque command sum can be maintained by the torque determination unit 502, the command correction unit 506 corrects the torque command to the remaining motor 3 so that the torque command sum is maintained. . As a result, the total driving force by all the wheels 2FL to 2RR can be maintained, so that not only the yaw rate behavior but also the acceleration in the front-rear direction can be maintained. As a result, even after the torque command is corrected, the vehicle can continue traveling at a speed state corresponding to the driver's accelerator pedal operation. Therefore, it is possible to prevent a thermal malfunction (burn-in or the like) of the motor 3 without deteriorating the running characteristics of the electric vehicle 1.

In the present embodiment, in particular, when the command correction unit 506 determines that the torque determination unit 502 cannot maintain the total torque command, the motor 3 corrects the torque command to the decrease side in the width direction of the electric vehicle 1. The torque command to the remaining motor 3 located on the opposite side of the motor is corrected to the decreasing side. As a result, the ratio of the total driving force of the left wheels 2FL and 2RL after correction of the torque command and the total driving force of the right wheels 2FR and 2RR is set to the ratio of the driving force of the left wheels 2FL and 2RL before correction. It is possible to make the ratio of the sum and the sum of the driving forces of the right wheels 2FR and 2RR the same. As a result, since it is possible to prevent the yaw moment generated in the vehicle body from changing, the certainty of maintaining the yaw rate behavior can be enhanced. Therefore, it is possible to prevent a thermal malfunction (burn-in) of the motor 3 while maintaining the turning characteristics of the electric vehicle 1.

In the present embodiment, in particular, the temperature estimation unit 503 estimates the temperature of the motor 3 after detection based on the temperature detected by the temperature sensor 6. Then, the state determination unit 505 determines that the thermal state of the motor 3 is not appropriate when the temperature estimated by the temperature estimation unit 503 exceeds the allowable temperature range. Since it is determined by determining whether or not the temperature of the motor 3 exceeds the allowable temperature range, it is possible to prevent thermal defects such as image sticking without overheating the motor 3. Therefore, the durability of the motor 3 can be improved.

In the present embodiment, in particular, the temperature determination unit 504 determines whether or not the detected temperature of the motor 3 whose torque command has been corrected to the decrease side has fallen below the upper limit value of the allowable temperature range. When the temperature determination unit 504 determines that the detected temperature has fallen below the upper limit value of the allowable temperature range, the command correction unit 506 gradually returns the torque command to the motor 3 corrected to the decrease side. As a result, when the thermal state of the motor 3 returns to an appropriate state, it is possible to immediately return to normal torque control (before correction), so that it is possible to reduce the influence on traveling due to correction of the torque command. In addition, since the torque command is gradually restored, the change in running characteristics becomes gradual, and the driver does not feel uncomfortable.

<6. Modified example>
In addition, embodiment is not restricted to the said content, A various deformation | transformation is possible within the range which does not deviate from the meaning and technical idea. Hereinafter, such modifications will be sequentially described.

(6-1. Selecting and executing the drive mode)
Hereinafter, with reference to FIG. 15, an example in which the example of the configuration of the controller of the present modification is specifically implemented with functional blocks will be described. In the following description, differences from the configuration of the controller 5 of the above embodiment will be mainly described.

As shown in FIG. 15, the configuration of the controller 5A of the present modification is different from the controller 5 of the above-described embodiment in that it has a new drive mode selection unit 510 and replaces the command correction unit 506 with the command correction. A point having a unit 506A (corresponding to an example of a first command correction unit and a second command correction unit).

In addition, the controller 5A is provided with four drive modes: “all wheel drive mode”, “front wheel drive mode”, “rear wheel drive mode”, and “diagonal wheel drive mode”. The all-wheel drive mode is a mode in which all the wheels 2FL to 2RR of the electric vehicle 1 are driven. The front wheel drive mode is a mode in which the wheels 2FL and 2FR in front of the electric vehicle 1 are driven. The rear wheel drive mode is a mode in which the wheels 2RL and 2RR behind the electric vehicle 1 are driven. The diagonal wheel drive mode is a mode for driving the right front wheel and left rear wheel 2FR, 2RL of the electric vehicle 1.

The diagonal wheel drive mode is not limited to a mode in which the right front and left rear wheels 2FR and 2RL of the electric vehicle 1 are driven, and the left front and right rear wheels 2FL of the electric vehicle 1 are not limited. , 2RR may be driven.

The drive mode selection unit 510 selects the four drive modes in the order of the all-wheel drive mode, the front wheel drive mode, the rear wheel drive mode, and the diagonal wheel drive mode according to, for example, the specifications and travel settings of the electric vehicle 1. Select and execute according to the priority order.

The command correction unit 506A, when the state determination unit 505 determines that the thermal state of any one or more of the two motors 3 in the drive ON state is not appropriate, the drive mode selection unit 510 In accordance with the drive mode selected and executed according to the priority order, the torque command to the motor 3 is corrected to the decrease side, and the remaining yaw moment of the electric vehicle 1 when the correction is not performed is maintained. The torque command to the motor 3 is corrected.

For example, when the all-wheel drive mode is selected and executed by the drive mode selection unit 510, all the motors 3FL to 3RR are turned on. If the state determination unit 505 determines that the thermal state of any one or more of the motors 3FL to 3RR is not appropriate, the command correction unit 506A and the command correction unit 506 of the above embodiment Similar processing is executed.

As shown in FIG. 16A, when the front wheel drive mode is selected and executed by the drive mode selection unit 510, among the motors 3FL to 3RR, the front wheel motors 3FL and 3FR are turned on, and the rear The wheel motors 3RL and 3RR are set in the drive OFF state. Then, as shown in FIG. 16B, when the state determination unit 505 determines that the thermal state of the front wheel motor 3FL is not appropriate, for example, the command correction unit 506A reduces the torque command to the front wheel motor 3FL. In addition, the torque command to the remaining front wheel motor 3FR is also corrected to the decreasing side so that the yaw moment of the electric vehicle 1 without the correction is maintained.

Further, as shown in FIG. 17A, when the rear wheel drive mode is selected and executed by the drive mode selection unit 510, the rear wheel motors 3RL and 3RR among the motors 3FL to 3RR are set in the drive ON state. The front wheel motors 3FL and 3FR are turned off. Then, as shown in FIG. 17B, when the state determination unit 505 determines that the thermal state of the rear wheel motor 3RL is not appropriate, for example, the command correction unit 506A issues a torque command to the rear wheel motor 3RL. While being corrected to the decrease side, the torque command to the remaining rear wheel motor 3RR is also corrected to the decrease side so that the yaw moment of the electric vehicle 1 without the correction is maintained.

As shown in FIG. 18A, when the diagonal wheel drive mode is selected and executed by the drive mode selection unit 510, among the motors 3FL to 3RR, the front wheel motor 3FR and the rear wheel motor 3RL are in the drive ON state. Thus, the front wheel motor 3FL and the rear wheel motor 3RR are turned off. As shown in FIG. 18B, when the state determination unit 505 determines that the thermal state of the front wheel motor 3FR is not appropriate, for example, the command correction unit 506A decreases the torque command to the front wheel motor 3FR. In addition, the torque command to the remaining rear wheel motor 3RL is also corrected to the decreasing side so that the yaw moment of the electric vehicle 1 when the correction is not performed is maintained.

According to this modification described above, the torque command can be corrected in accordance with the optimum drive mode according to the specifications of the electric vehicle 1 and the travel settings. Further, for example, in the all-wheel drive mode, since the driving force distribution of the wheels 2FL to 2RR can be optimally determined according to the weight distribution of the vehicle body, the vehicle motion characteristics can be set to the safest side, In the front wheel drive mode, the turning characteristic becomes understeer, so that the vehicle body is hard to spin and the vehicle movement characteristic can be set to the safe side. Therefore, the driving safety can be improved by setting the priority order with the driving mode having a high safety as the higher order.

(6-2. Others)
In the above, the temperatures of the motors 3FL to 3RR are individually detected by the temperature sensors 6FL to 6RR, and the state determination unit 505 determines whether or not the thermal state of the motor 3 is appropriate based on the temperature detected by the temperature sensor 6. The case where the command correction unit 506 corrects the torque command when it is determined that the thermal state of any one or more motors 3 is not appropriate has been described. However, the embodiment is not limited to such contents. For example, four state sensors individually detect states other than the temperatures of the motors 3FL to 3RR, and based on the detection results of the state sensors, the state determination unit determines whether the state of the motor 3 is appropriate. When it is determined that the state of one or more motors 3 is not appropriate, the torque correction command may be corrected by the command correction unit.

In addition, in the above description, when there are descriptions such as “vertical”, “parallel”, and “plane”, the descriptions are not strict. That is, the terms “vertical”, “parallel”, “plane”, etc., allow tolerances and errors in design and mean “substantially vertical”, “substantially parallel”, “substantially plane”, etc. It is.

In addition, in the above description, when there is a description such as “same”, “equal”, “different”, etc., in terms of external dimensions and size, the description is not strict. That is, the terms “same”, “equal”, “different”, etc. mean that “tolerance and error in design and manufacturing are allowed”, “substantially the same”, “substantially equal”, “substantially different”, etc. It is.

However, if there is a description of a value that becomes a predetermined judgment criterion or a value that becomes a delimiter, such as a threshold value or a reference value, the “same”, “equal”, “different” etc. It is different and has a strict meaning.

Further, the arrows shown in FIGS. 1, 6 and 15 show an example of the flow of the signal or power, and do not limit the flow direction of the signal or power.

In addition to those already described above, the methods according to the above-described embodiment and each modification may be used in appropriate combination.

In addition, although not illustrated one by one, the above-described embodiment and each modification are implemented with various modifications within a range not departing from the gist thereof.

1 Electric vehicle 2FL, FR, RL, RR Wheel 3FL, FR, RL, RR Motor (an example of a rotating electrical machine)
5 Controller 5A Controller 6FL, FR, RL, RR Temperature sensor (example of status sensor)
DESCRIPTION OF SYMBOLS 10 Stator 12 Stator winding 30 Rotor 25FL, FR, RL, RR Rotational speed sensor 49 Control motor 52 1st permanent magnet (an example of field magnet)
53 1st magnetic pole part (an example of a magnetic pole part)
63 2nd magnetic pole part (an example of a magnetic pole part)
502 torque determination unit 503 temperature estimation unit 504 temperature determination unit 505 state determination unit (an example of a first state determination unit and a second state determination unit)
506 Command correction unit (an example of a first command correction unit and a second command correction unit)
506A Command correction unit (an example of a first command correction unit and a second command correction unit)
507 Field controller (an example of a first field controller and a second field controller)
510 Drive Mode Selection Unit Sy Drive Force Control System

Claims

An electric vehicle driving force control system for controlling the driving force of a plurality of wheels of an electric vehicle,
A plurality of motors configured to change the field magnetic flux and individually driving the plurality of wheels;
The same number of state sensors as the motors for individually detecting the states of the plurality of motors;
A first state determination unit that determines whether or not the state of the motor is appropriate based on a detection result of the state sensor;
When the first state determination unit determines that the state of any one or more of the plurality of motors is not appropriate, the torque command to the motor is corrected to the decrease side and the correction A first command correction unit that corrects torque commands to the remaining motors so that the yaw moment of the electric vehicle when not being
A first field control unit for individually controlling the field magnetic flux of the plurality of motors based on the torque command corrected by the first command correction unit;
A driving force control system for an electric vehicle characterized by comprising:
An electric vehicle driving force control system for controlling the driving force of a plurality of wheels of an electric vehicle,
A plurality of motors configured to change the field magnetic flux and individually driving the plurality of wheels;
Detecting the temperatures of the plurality of motors individually, the same number of temperature sensors as the motors;
A second state determination unit that determines whether or not the thermal state of the motor is appropriate based on the temperature detected by the temperature sensor;
When the second state determination unit determines that the thermal state of any one or more of the plurality of motors is not appropriate, corrects the torque command to the motor to the decrease side, and A second command correction unit that corrects torque commands to the remaining motors so that the yaw moment of the electric vehicle when the correction is not performed is maintained;
A second field control unit for individually controlling field magnetic fluxes of the plurality of motors based on the torque command corrected by the second command correction unit;
A driving force control system for an electric vehicle characterized by comprising:
The motor is
A stator with a stator winding;
A rotor configured such that a plurality of magnetic pole portions in which field magnets are installed are divided into two sets and rotate relatively;
A control motor for relatively rotating two sets of the magnetic pole portions,
The first field controller or the second field controller is
3. The driving force control system for an electric vehicle according to claim 1, wherein a field magnetic flux of the motor is controlled by controlling the control motor based on the torque command.
Further comprising the same number of rotation speed sensors as the motors for individually detecting the rotation speeds of the plurality of motors;
The first field controller or the second field controller is
Based on the rotational speed and the torque command, two sets of the magnetic pole portions having the same polarity are aligned and the induced voltage in the state where the two magnetic pole portions are rotated relative to the induced voltage constant in the state where the field is strongest. Map control that reads out the field ratio, which is a constant ratio, the phase angle of the current applied to the stator winding with respect to the magnetic pole position created by the two sets of magnetic pole portions, and the target value of the current with reference to the map The driving force control system for an electric vehicle according to claim 3, wherein:
Whether or not the sum of the torque commands to all the motors when the torque command is corrected based on the maximum torque of the motor can maintain the sum of the torque commands when the torque command is not corrected A torque determination unit for determining;
The first command correction unit or the second command correction unit is
The torque command to the remaining motors is corrected so that the sum of the torque commands is maintained when the torque determination unit determines that the sum of the torque commands can be maintained. Item 5. The driving force control system for an electric vehicle according to any one of Items 1 to 4.
The first command correction unit or the second command correction unit is
When it is determined by the torque determination unit that the sum of the torque commands cannot be maintained, the remaining motors positioned on the opposite side of the motor that has corrected the torque commands to the decreasing side in the width direction of the electric vehicle 6. The driving force control system for an electric vehicle according to claim 5, wherein the torque command is corrected to a decreasing side.
A temperature estimation unit that estimates the temperature of the motor after detection based on the detection temperature of the temperature sensor;
The second state determination unit
3. The thermal state of the motor is determined to be inappropriate when the temperature estimated by the temperature estimation unit exceeds an allowable temperature range that is a temperature range in which no thermal failure occurs in the motor. The driving force control system for an electric vehicle according to any one of claims 1 to 6.
A temperature determination unit that determines whether or not the detected temperature of the motor that has corrected the torque command to the decrease side is lower than an upper limit value of the allowable temperature range;
The second command correction unit is
8. The electric vehicle according to claim 7, wherein when the temperature determination unit determines that the detected temperature is lower than the upper limit value, the torque command of the motor corrected to decrease is gradually returned. Driving force control system.
Of the four wheels provided in the front, rear, left, and right of the electric vehicle, an all-wheel drive mode for driving all the wheels, a front wheel drive mode for driving the front wheels, and a rear wheel drive mode for driving the rear wheels. Four wheel drive modes, right wheel front and left rear wheel or diagonal wheel drive mode for driving left wheel front and right rear wheel, the all wheel drive mode, the front wheel drive mode, and the rear wheel drive. A drive mode selection unit that selects and executes the priority according to the order of the modes and the diagonal wheel drive modes,
The first command correction unit or the second command correction unit is
According to the drive mode selected and executed by the drive mode selection unit according to the priority order, the torque command to the motor is corrected to the decrease side, and the yaw moment of the electric vehicle when the correction is not performed is maintained. As described above, the torque command to the remaining motor is corrected, and the driving force control system for an electric vehicle according to any one of claims 1 to 8.
Multiple wheels,
The driving force control system according to any one of claims 1 to 9,
An electric vehicle comprising:
A rotating electrical machine provided in the driving force control system for an electric vehicle according to any one of claims 1 to 9, and configured to change a field magnetic flux.