JP2020129935A - Vehicle power assistance system - Google Patents

Abstract

To provide a vehicle power assistance system which can bring SOC of a direct current power supply close to an optimum value while assuring improvement effect of yaw angular speed responsibility to steering by DYC.SOLUTION: A vehicle power assistance system comprises: each motor generator 102, 102 for exclusive use of DYC which generates a driving torque and a regenerative torque independently with left and right wheels 101, 101 in any one or both of front and rear wheels; each power inverter circuit 105, 105 for the left and right wheels; and a controller 110. The controller 110 calculates a torque required for the left and right motor generators 102, 102 by use of a rotation angle of each steering device 109 and a vehicle speed in order to generate a target yaw moment, and gives the same to each power inverter circuit 105, 105 as a torque command value. The controller 110 changes distribution of the torque command value given to the power inverter circuits 105, 105 for the left and right wheels depending on SOC value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle power assist system having a function of yaw moment control based on a driving force difference between left and right wheels, so-called direct yaw moment control (hereinafter abbreviated as DYC).

Conventionally, it has been proposed to generate a target yaw moment by a driving force difference between left and right wheels in an automobile equipped with an in-wheel motor to improve the response of the yaw angular velocity in the initial stage of the steering operation (Patent Document 1). ). The document also describes that the power source for driving the left and right wheels may be a single electric motor or engine (internal combustion engine).

JP, 2016-163459, A

Generally, in order to protect the power source, drive is limited when the state of charge (hereinafter, abbreviated as SOC) of the DC power source is below a lower limit threshold value, and regeneration is limited when it is above an upper limit threshold value. I am trying to do it.
In the invention described in Patent Document 1, half of the torque for generating the target yaw moment is increased/decreased for each of the left and right wheels, and the left and right torque distribution amounts (absolute values) are equal. When the electric motor is used as the power source in the invention of Patent Document 1, when the SOC of the DC power source is below the lower limit threshold value and above the upper limit threshold value, driving and regeneration are limited, and the required torque is left and right. It cannot be generated in the wheel, and the effect of improving the response of the yaw angular velocity becomes small.

An object of the present invention is to provide a vehicle power assist system that can bring the SOC of the DC power supply close to an optimum value while ensuring the effect of improving the response of the yaw angular velocity to steering by DYC.

The vehicle power assist system of the present invention includes left and right wheel motor generators that independently generate drive torque and regenerative torque on the left and right wheels on either or both of the front and rear wheels,
A DC power source commonly used for both motor generators,
Each power conversion circuit for the left and right wheels, which is provided between the DC power source and each of the motor generators, receives a torque command, and supplies power corresponding to the torque command to each of the motor generators,
An SOC detector for detecting the SOC value of the DC power supply,
An angle detector that detects the rotation angle of the vehicle steering device,
A speed detector for detecting the speed of the vehicle,
In yaw moment control based on the driving force difference between the left and right wheels, a torque required by the left and right motor generators is calculated using the rotation angle of the steering device and the vehicle speed in order to generate a target yaw moment. A controller provided as a torque command value to each power conversion circuit for the left and right wheels,
The controller changes distribution of the torque command value given to the power conversion circuits for the left and right wheels according to the SOC value obtained by the SOC detector.

With this configuration, the controller calculates the torque necessary for controlling the yaw moment due to the driving force difference between the left and right wheels by using the rotation angle of the steering device and the speed of the vehicle. Moment control, that is, DYC can be performed.
The DYC is a yaw moment control based on the driving force difference between the left and right wheels, but if the driving force difference between the left and right wheels is maintained, similar yaw moment control can be performed even if the left and right torque distribution amounts are different. For example, when the driving force difference between the left and right wheels is +100, conventionally, the torque distribution amounts (absolute values) of the left and right wheels are equal, and the inside of the turn is set to -50 and the outside of the turn is set to +50. Even if is set to +30, the driving force difference between the left and right wheels is +100, and the effect of yaw moment control remains unchanged. On the other hand, if the amount of torque generation of the left and right wheels is changed, the amount of power consumption and the amount of charge due to regeneration change.
This invention pays attention to this principle, and changes the distribution of the torque command value given to the power conversion circuits for the left and right wheels according to the SOC value of the DC power supply. Therefore, it is possible to bring the SOC of the DC power supply close to the optimum value while ensuring the effect of improving the response of the yaw angular velocity to the steering by DYC.

In the present invention, the controller calculates a yaw moment for improving the response of the yaw angular velocity to steering from the speed of the vehicle and the rotation angle of the steering device, and further optimizes the value of the SOC of the DC power supply. You may make it calculate the torque of the said motor generator which approaches a value.
Although there are several types of DYC, in this configuration, since the yaw moment for improving the response of the yaw angular velocity is calculated, a more appropriate response of the yaw angular velocity by DYC can be obtained. After calculating such a yaw moment, the torque of each dynamic generator that brings the SOC value of the DC power supply closer to the optimum value is calculated. Therefore, while improving the responsiveness of the yaw angular velocity to the steering by DYC, The SOC can be brought close to the optimum value. The optimum SOC value may be slightly different from the actual optimum value, and is set appropriately. The optimum value is a value that can achieve both charging (regeneration) and discharging (driving) that are expected in normal traveling (a state in which there is enough capacity for charging and discharging). For example, when the charging ability and the discharging ability are the same, the optimum value is set to 50% of the maximum chargeable capacity. Further, for example, when the discharging capacity is larger than the charging capacity, the optimum value is set to 60% of the maximum chargeable capacity or the like.

In the present invention, the motor generator may be provided as a wheel bearing device with a motor generator in a wheel bearing of a driven wheel that is a wheel that is not connected to the main drive source of the vehicle.
By providing a motor/generator for DYC in a wheel bearing as a motor-generator-equipped wheel bearing device that is an integrated assembly, compactness and good handleability can be achieved. Further, by disposing the bearing device for a wheel with a motor/generator on the driven wheels, the motor/generator can be installed in a vehicle not equipped with the motor/generator without a major design change around the wheel.
When the motor generator is dedicated to DYC, unlike the in-wheel motor for driving the vehicle, it only needs to be large enough to fit on the wheels. Therefore, it is necessary to install the motor generator on the wheels. Can be done without major design changes.

In the present invention, the controller may obtain a differential torque based on the necessary yaw moment and output a torque command value of a torque distribution rate determined for the differential torque.
By determining an appropriate torque distribution ratio and distributing the differential torque based on the required yaw moment at the torque distribution ratio, the SOC of the DC power supply can be maintained while ensuring the effect of improving the response of the yaw angular velocity to steering by DYC. It is easy to perform control to approach the optimum value. The torque distribution rate may be set in a map or set in a calculation formula, for example.

In the case of this configuration, the controller may calculate the torque distribution rate of the left and right motor generators based on at least the SOC value of the DC power supply.
By calculating the torque distribution rates of the left and right motor generators based on the SOC value, the SOC can always be set to the optimum value.

In addition, the controller maintains a torque that generates a yaw moment required for yaw moment control by the driving force difference when the generated torque of the motor generator reaches the maximum torque that can be driven or regenerated. Thus, the torque of each of the left and right motor generators may be corrected.
The torque that can drive the motor-generator and the maximum torque that can be regenerated are determined by the motor-generator, and torque above this cannot be obtained even if the torque command value is increased. In such a case, in this example, the torques of the left and right motor generators are corrected so as to maintain the torque that generates the yaw moment required for yaw moment control. For example, when the drive-side motor/generator under the DYC control reaches the maximum torque, the absolute value of the torque command value of the regenerative-side motor/generator is corrected to be large.
In this case, although the control moves away from the control in which the SOC is set to the optimum value according to the degree of correction, the yaw moment required for the yaw moment control due to the driving force difference is maintained, and the curve running can be performed with an appropriate yaw moment.

The controller corrects the torque of each motor generator for the left and right wheels so as to maintain the charged or discharged state when the generated torque of the motor generator reaches the maximum torque that can be driven or regenerated. You may do so.
In this case, the controllability of the yaw moment control due to the driving force difference is somewhat lowered, but the function of making the SOC value the optimum value is maintained.

The vehicle power assist system of the present invention includes left and right wheel motor generators that independently generate drive torque and regenerative torque on the left and right wheels on either or both of the front and rear wheels,
A DC power source commonly used for both motor generators,
Each power conversion circuit for the left and right wheels, which is provided between the DC power source and each of the motor generators, receives a torque command, and supplies power corresponding to the torque command to each of the motor generators,
An SOC detector for detecting the SOC value of the DC power supply,
An angle detector that detects the rotation angle of the vehicle steering device,
A speed detector for detecting the speed of the vehicle,
In yaw moment control based on the driving force difference between the left and right wheels, a torque required by the left and right motor generators is calculated using the rotation angle of the steering device and the vehicle speed in order to generate a target yaw moment. A controller provided as a torque command value to each power conversion circuit for the left and right wheels,
This controller changes the distribution of the torque command value given to the power conversion circuits for the left and right wheels according to the value of the SOC obtained by the SOC detector.
It is possible to bring the SOC of the DC power supply close to the optimum value while ensuring the effect of improving the response of the yaw angular velocity to the steering by DYC.

It is a conceptual diagram which shows an example of the vehicle carrying the vehicle power assistance system which concerns on one Embodiment of this invention in a top view. It is a conceptual diagram which shows a vehicle power assistance system by a top view. FIG. 3 is a block diagram showing an example of a conceptual configuration of a controller in the vehicle power assist system. FIG. 3 is a vertical cross-sectional view showing an example in which a motor generator in the vehicle power assist system is installed on a wheel bearing together with the wheel. (A)-(f) of the figure is an explanatory view showing each example of torque distribution by the controller of the vehicle power assist system. It is a graph which shows the example of determination of the torque distribution rate by the controller of the same vehicle power assistance system. It is a graph which shows the other example of determination of the torque distribution rate by the controller of the same vehicle power assistance system. It is a graph which shows an example of the relationship between the torque of a motor generator on either side and the difference torque in the vehicle power auxiliary system. 6 is a graph showing another example of the relationship between the torque of the left and right motor generators and the differential torque in the vehicle power assist system.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a vehicle including this vehicle power assist system. An engine 201, which is a main drive source of the vehicle 1, is mechanically connected to drive wheels 204 via a clutch 202 and a transmission 203. A motor generator 102 that constitutes this vehicle power assist system is mounted on a wheel 101 that is a driven wheel that is mechanically uncoupled from the drive wheel 204.
In the example of FIG. 1, the motor generator 102 may be mounted on the drive wheels 204 connected to the engine 201. The engine 201, which is the main drive source, may drive either the front wheels or the rear wheels, or may drive the four wheels. Further, the main drive source may be a motor generator different from the motor generator 102, or may be a hybrid type in which an engine and a motor generator are combined.

The motor generator 102 is a motor that generates a driving force by supplying electric power and conversely converts kinetic energy of the vehicle into electric power to generate electric power. In this example, a direct drive motor that does not use a transmission is used. is there. The motor generator 102 may be a synchronous motor, an induction motor, a DC motor or the like as long as it can convert electric energy and rotational energy to each other, and may include a speed change mechanism.

The motor generator 102 is installed integrally with the wheel bearing of the wheel 101. The motor generator 102 in this embodiment is used only for outputting a torque for generating a target yaw moment, and can be downsized as compared with the case where it is used as a main drive source. Therefore, the size of the tire can be easily accommodated in the tire wheel, and no major modification is required even when the tire is mounted on an existing vehicle.

FIG. 4 shows a specific example of the motor generator 102. The motor generator 102 is provided as a wheel bearing device 10 with a motor generator on the wheel bearing 2 of the wheel 101 that is a driven wheel. That is, the wheel bearing 2 and the motor generator 102 constitute a wheel generator bearing device 10 with a motor generator that is an integral assembly.

In the wheel bearing 2, an inner ring 5 is rotatably supported by an outer ring 4, which is a fixed ring, via double-row rolling elements 6. The inner ring 5 has a hub flange 7 at a location projecting more toward the outboard side in the axial direction than the outer ring 4. The outer ring 4 is attached to the undercarriage frame component 8 such as a knuckle with a bolt (not shown) on the vehicle body mounting surface 4a that is the end portion (inboard side) opposite to the hub flange 7, and supports the weight of the vehicle body. .. In this specification, the side closer to the outer side in the vehicle width direction of the vehicle when the vehicle power unit 1 is mounted on the vehicle is called the outboard side, and the side closer to the center in the vehicle width direction of the vehicle is the inboard side. Call it the board side.

A rim 11 of the wheel 101 and a disc type brake rotor 12 are attached to a side surface of the hub flange 7 on the outboard side by a hub bolt 13 in a state of overlapping in the axial direction. Tires 14 are attached to the outer periphery of the rim 11. The brake rotor 12 and a brake caliper (not shown) (not shown) form a brake 17 that is a friction brake.

The motor generator 102 has a stator 18 attached to the outer peripheral surface of the outer ring 4 of the wheel bearing 2, and a motor rotor 19 attached to the hub flange 7 of the inner ring 5. The stator 18 has a core 18a and coils (not shown) wound around each tooth of the core 18a. The motor rotor 19 includes a rotating case 19a serving as a motor case, a magnetic body 19b provided on the inner circumference of the rotating case 19a, and a permanent magnet (not shown) built in the magnetic body 19b. The rotating case 19a is a hub. It is attached to the flange 7.

The entire motor generator 102 has a smaller diameter than the cylindrical outer peripheral portion 12a of the brake rotor 12. Further, the entire portion of the motor generator 102 excluding the mounting portion to the hub flange 7 is located in the axial range L1 between the inboard side vehicle body mounting surface 4a of the wheel bearing 2 and the hub flange 7. That is, the motor generator 102 is housed in the radial range between the outer peripheral portion 12b of the brake rotor 12 and the outer periphery of the outer ring 4.

FIG. 2 is a conceptual view showing the vehicle power assist system of this embodiment in a plan view.
The motor generator 102 is mounted on at least one of the front and rear wheels 101, 101 of the vehicle 1 as described above.
The steering device 108 is a device that steers a wheel to be a steered wheel, for example, a wheel 101 to be a front wheel, in accordance with a command given by a steering wheel (not shown) or a host controller (not shown) for automatic driving. Is.
The angle detector 109 detects the angle of the steering device 108. The "angle of the steering device 108" referred to here may be the rotation angle of the bundle on the operating side or the steering angle of the wheel 101 whose angle is changed as a result of the operation.

The DC power source 106 is a power source that is commonly used by the left and right motor generators 102 and 102, and the motor generators 102 and 102 are provided via power conversion circuits 105 and 105 provided for the motor generators 102 and 102, respectively. Connected to. As the DC power supply 106, a secondary battery or a capacitor that can be repeatedly charged and discharged is used. A lithium ion battery or a lead storage battery is used as the secondary battery.
The SOC detector 107 detects the SOC of the DC power supply 106 in the charged state. This SOC is a value indicating the degree of charge from full charge to empty charge. Specifically, regarding the amount of electric charge (unit [Ah]) stored in the DC power supply 106,
SOC = (remaining capacity [Ah]) / (full charge capacity [Ah])
Is.
Since the voltage of the DC power source 106 generally changes slightly depending on the degree of charging, the SOC detector 107 may detect the SOC by directly detecting the voltage. In that case, the output value of the SOC detector 107 may be a voltage value instead of the SOC value.

The power conversion circuit 105 is a circuit that is provided between the DC power supply 106 and each of the motor generators 102, receives a torque command, and gives power corresponding to the torque command to the motor generator 102. The power conversion circuit 105 controls the output of the inverter by receiving the torque command and an inverter (not shown) that mutually converts the DC power of the DC power supply 106 and the AC power corresponding to the motor generator 102. Power control means (not shown). The inverter is a device having a function of converting DC power into AC power, as well as a function of converting AC power that is regenerative power generated by the motor generator 102 into DC, that is, a function as an AC/DC converter. .. The inverter is an inverter that converts direct current and three-phase alternating current to each other if the motor generator 102 is a three-phase alternating current motor generator. When the applied torque command has a negative value, the power control means in the power conversion circuit 105 converts AC regenerative power into DC.

An angle detector 103 provided along with the motor generator 102 detects the rotation angle of the motor generator 102. The angle detector 103 may use any one of a resolver, an optical encoder, a magnetic encoder, a Hall sensor, and an MR sensor.
The speed calculator 104 acquires the rotation angles of the two motor generators 102 from the angle detector 103 of each motor generator 102, and calculates the rotation speed of each motor generator 102 and the speed of the vehicle 1.

The controller 110 is a control unit that performs yaw moment control based on the driving force difference between the left and right wheels 101, 101, and the torque required by the left and right motor generators 101, 101 to generate the target yaw moment. Is calculated and given as a torque command value to each of the power conversion circuits 105, 105 for the left and right wheels.

As shown in a specific example in FIG. 3, the controller 110 includes a yaw moment calculation unit 111, a torque calculation unit 112, and a torque correction unit 113.
The yaw moment calculation unit 111 calculates a target yaw moment by DYC based on the speed of the vehicle 1 and the angle of the steering device 108.
The torque calculation unit 112 calculates the torque required for the motor generator 102 based on at least the target yaw moment and the SOC of the DC power supply 106.
The torque correction unit 113 corrects the required torque based on the maximum torque that can drive or regenerate the motor generator 102, for example, as described later with reference to FIG. 8 or FIG. 9, and outputs the torque command value to the power conversion circuit 105. Is applied to control the drive torque or the regenerative torque of the left and right motor generators 102 individually. The maximum torque that the motor generator 102 can drive and the maximum torque that can be regenerated are determined by the motor generator 102, and the maximum torque is determined by the torque correction unit 113 as a parameter or in a control formula. There is.

In the following, an example of a method in which the controller 110 calculates and controls the torque of the motor generator 102 according to the SOC of the DC power supply 106 will be described.

<Response of yaw angular velocity to steering and yaw moment>
Regarding the coordinate system fixed to the vehicle 1, assuming that the left and right tire characteristics and the sideslip angles are the same for both the front and rear wheels, describing the vehicle motion using the planar two-degree-of-freedom model, the lateral motion of the vehicle 1 and the vehicle center of gravity point are described. The yawing motion about the vertical axis passing through is represented by equations (1) and (2), respectively, with the counterclockwise direction being positive.

When the equations (1) and (2) are Laplace transformed and arranged, the yaw angular velocity with respect to the steering and the yaw moment is expressed by the equation (3).

From the equation (3), the yaw angular velocity γ _δ (s) generated by the steering angle and the yaw angular velocity γ _M (s) generated by the yaw moment are represented by the equations (4) and (5), respectively.

ここで、αは制御パラメータである。 <Calculation of yaw moment in DYC>
The target yaw angular velocity γ _t (s) is set as in equation (6).

Here, α is a control parameter.

By compensating for the difference between the target yaw angular velocity γ _t (s) and the yaw angular velocity γ _δ (s) generated by the steering angle with the yaw angular velocity γ _M (s) generated by the yaw moment, the response of the yaw angular velocity is improved. improves. Therefore, γ _M (s) is given by equation (7).

By substituting Equation (4), Equation (5), and Equation (6) into Equation (7) and rearranging, the yaw moment M _Z (s) is represented by Equation (8).

したがって、式（６）のαによって目標とするヨー角速度γ_ｔ（ｓ）を決定し、これを式（８）のヨーモーメントM_Z（ｓ）で実現する。

Therefore, the target yaw angular velocity γ _t (s) is determined by α in Expression (6), and this is realized by the yaw moment M _Z (s) in Expression (8).

<Calculation of motor generator torque>
Of the front and rear wheels, the tread on the side where the motor generator 102 is mounted is D, the dynamic effective radius of the tire 14 of the wheel 101 on which the motor generator 102 is mounted is R, and the torque of the left and right motor generators 102 is T, respectively. _L, and the _{T R,} the difference torque _{T d} of the left and right of the motor generator 102 for generating the yaw moment _{M z} is expressed by equation (9). However, T _L and T _R are positive in the direction (drive) for moving the vehicle 1 forward, and the yaw moment is positive in the counterclockwise direction when viewed from above the vehicle.

Here, ε is the ratio of the drive torque or the regenerative torque to the differential torque T _d , and is called the torque distribution rate. The torque distribution ratio ε is represented by the equation (12). When ε=1, the driving torque is the largest, and when ε=−1, the regenerative torque is the largest.

For example, the torques T _L and T _R of the left and right motor generators 102 at the differential torque T _d =+100 and the differential torque T _d =−100 are as shown in FIG. The drive torque and the regenerative torque change according to the torque distribution ratio ε, and the SOC also changes accordingly. By determining the torque distribution ratio ε to an appropriate value, the SOC can be brought close to the optimum value.

5 (a) is the difference torque _T d = + 100, shows the case of a torque distribution ratio epsilon = -0.4, torque _T L of the left and right electric generator 102, _{T R} are each _T L = -70, it is a T _R = + 30.
FIG. 5 (b), the difference torque _T d = + 100, shows the case of a torque distribution ratio epsilon = 0.0, the torque _T L of the left and right electric generator 102, _{T R,} as in the prior art, respectively _{T L} = _-50, a T R = + 50.
FIG. 5 (c), differential torque _T d = + 100, shows the case of a torque distribution ratio epsilon = 0.4, the torque _T L of the left and right electric generator 102, _{T R} are each _T L = -30, T _R =+70.

5 (d) is the difference torque _T d = -100, shows the case of a torque distribution ratio epsilon = -0.4, torque _T L of the left and right electric generator 102, _{T R} are each _T L = + 30, it is a T _R = -70.
Figure 5 (e) shows a case of the differential torque _T d = -100, the torque distribution ratio epsilon = 0.0, the torque _T L of the left and right electric generator 102, _{T R,} as in the prior art, respectively _{T L} = + _50, T R = -50.
Figure 5 (f) shows a case of the differential torque _T d = -100, the torque distribution ratio epsilon = 0.4, the torque _T L of the left and right electric generator 102, _{T R} are each _T L = + 70, _{T R} =-30.

<Calculation of torque distribution rate>
The torque distribution ratio ε is determined as shown in FIG. 6, for example.
(A) When SOC is the optimum value
The torque distribution ratio ε _o is such that the absolute value of the power consumption due to the driving torque and the absolute value of the recovered power due to the regenerative torque are equal.
(B) When SOC is less than the optimum value
It is set to a value smaller than the torque distribution rate ε _o which is the matching value so that the power consumption by the driving torque is lower than the recovered power by the regenerative torque.
(C) When SOC is higher than the optimum value
It is set to a value larger than the torque distribution rate ε _{o at} which the absolute values are the same so that the power consumption by the driving torque exceeds the recovered power by the regenerative torque.

Ε for SOC does not have to be linear, and may be determined as shown in FIG. 7, for example. In the example of the figure, the gradient is gentle in the vicinity of the torque distribution ratio ε _o at which the absolute values match and in the vicinity of the torque distribution ratio = 1 or the torque distribution ratio = -1. In addition, the torque distribution ratio ε may be calculated and determined from the SOC, the rotation speed of the motor generator 102, the efficiency, etc., instead of being obtained from the map.

<Correction of motor generator torque>
8 and 9 show examples of corrections performed by the torque correction unit 113 (see FIG. 3) when the torque of the motor generator 102 reaches the maximum torque that can be driven or regenerated.
When the torque of the motor generator 102 reaches the maximum torque that can be driven or regenerated, as shown in FIGS. 8 and 9, the torque T _L , T _R of the motor generator 102 is set as follows. May be decided again.
For example, when the SOC of the DC power supply 106 is near the optimum value, the correction shown in FIG. 8 is adopted by giving priority to the generation of the yaw moment required for the DYC, and when the SOC of the DC power supply 106 is too small or too large, charging is performed. Alternatively, the correction of FIG. 9 is adopted with priority given to making the SOC of the DC power supply 106 closer to the optimum value by discharging.
Here, the maximum torque that can be driven or regenerated may be determined in advance or may be determined by calculation in consideration of conditions such as the rotation speed and temperature of the motor generator 102.

In the example shown in FIG. 8, when one of the motor generators 102 reaches the maximum torque, the torque lacking in one of the motor generators 102 is subtracted from the torque of the other motor generator 102 to obtain the difference torque T _d. = to maintain the _T R -T _L. Although the torque distribution ratio ε changes, the yaw moment necessary for DYC can be generated.
When T _M , T ₁ , T ₁ ′, T ₂ and T ₂ ′ are defined as follows, T ₁ and T _{2 in} the region where the maximum torque that can be driven or regenerated exceeds the maximum torque can be expressed by equation (13). It FIG. 8 shows an example of the torques T ₁ and T ₂ of the motor generator 102 with respect to the differential torque.
T _M: drive or regenerative capable maximum torque T _1: the _{T M} motor generator 102 has been reached, the corrected torque T ₁ ': of the motor generator 102 reaches _{T M,} uncorrected torque T ₂ : of the motor generator 102 is not reached _{T M,} the torque T ₂ of the corrected ': the motor generator 102 is not reached _{T M,} uncorrected torque

In the control example of FIG. 9, when T ₁ reaches T _M , T ₂ also maintains the torque at that time and maintains the torque distribution ratio ε. The differential torque T _d changes, but the charge state or the discharge state does not change. _Assuming that T ₂ when T ₁ reaches T _M is T′ _M , T ₁ and T _{2 in} a region in which the maximum torque that can be driven or regenerated is exceeded are expressed by equation (14). FIG. 9 shows an example of the torques T ₁ and T ₂ of the motor generator 102 with respect to the differential torque T _d .

As described above, according to this embodiment, the response of the yaw angular velocity to steering is improved by DYC, and the ratio of the drive torque and the regenerative torque that generate the required yaw moment is appropriately determined to optimize the SOC of the DC power supply 106. It can be close to the value.

The embodiments for carrying out the present invention have been described above based on the embodiments. However, the embodiments disclosed herein are exemplifications in all respects and are not restrictive. The scope of the present invention is shown not by the above description but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

DESCRIPTION OF SYMBOLS 1... Vehicle, 4... Outer ring, 5... Inner ring, 6... Rolling element, 7... Hub flange, 10... Wheel bearing device, 101... Wheel, 102... Motor generator, 105... Power conversion circuit, 106... DC power supply, 107... SOC detector, 108... Steering device, 109... Angle detector, 110... Controller, 111... Yaw moment calculation unit, 112... Torque calculation unit, 113... Torque correction unit, 201... Engine, 204... Driving wheel, 201... Wheels (driven wheels)

Claims (7)

Each motor generator for the left and right wheels that independently generates drive torque and regenerative torque on the left and right wheels on either or both of the front and rear wheels,
A direct current power source commonly used for both motor generators,
Each power conversion circuit for the left and right wheels, which is provided between the DC power source and each of the motor generators, receives a torque command, and supplies power corresponding to the torque command to each of the motor generators,
An SOC detector for detecting the SOC value of the DC power supply,
An angle detector that detects the rotation angle of the vehicle steering device,
A speed detector for detecting the speed of the vehicle,
In yaw moment control based on the driving force difference between the left and right wheels, the torque required by the left and right motor generators is calculated using the rotation angle of the steering device and the speed of the vehicle in order to generate a target yaw moment. A controller provided as a torque command value to each power conversion circuit for the left and right wheels,
The controller changes distribution of the torque command value given to the power conversion circuits for the left and right wheels according to the SOC value obtained by the SOC detector.
Vehicle power assistance system. The vehicle power assist system according to claim 1, wherein the controller calculates a yaw moment for improving a response of a yaw angular velocity to steering from a speed of the vehicle and a rotation angle of the steering device, and further, the DC A vehicle power assist system for calculating a torque of the motor generator that brings the SOC value of the power source close to an optimum value. The vehicle power assist system according to claim 1 or 2, wherein the motor-generator is mounted on a wheel bearing of a driven wheel, which is a wheel that is not connected to a main drive source of the vehicle, and a wheel with a motor-generator. A vehicle power assist system provided as a bearing device. The vehicle power assist system according to any one of claims 1 to 3, wherein the controller obtains a differential torque based on the necessary yaw moment, and a torque distribution ratio of a torque distribution rate determined with respect to the differential torque. A vehicle power assist system that outputs a torque command value. The vehicle power assist system according to claim 4, wherein the controller calculates a torque distribution rate of the left and right motor generators based on at least the SOC value of the DC power supply. The vehicle power assist system according to claim 4 or 5, wherein the controller controls the yaw due to the driving force difference when the generated torque of the motor generator reaches a maximum torque that can be driven or regenerated. A vehicle power assist system for correcting the torque of each of the left and right motor generators so as to maintain the torque that generates a yaw moment required for moment control. The vehicle power assist system according to claim 4 or 5, wherein the controller maintains a charge or discharge state when the generated torque of the motor generator reaches a maximum torque that can be driven or regenerated. A vehicle power assist system for correcting the torque of each of the motor generators for the left and right wheels.

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