JPH09252505A - Drive control apparatus for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a drive control apparatus which suppresses the rotation speed rise of a motor when a wheel slips, by a method wherein the difference in the detection value of the speed of rotation of the motor between wheels is found and, when the difference is at a predetermined value or higher, a torque instruction value on the side on which of the motor rotation speed is high is subtracted according to the difference. SOLUTION: The rotation speed of every wheel is detected by speed detection parts 9 at respective controllers X1, X2 so as to be computed by an adder 10, and a result is inputted to discriminators 111, 112. Then, when their difference is at an instruction value or higher, a torque instruction value is subtracted by an adder 141, 142 and outputted. As a result, when a switch 121 or 122 is closed, a torque instruction value on the side of a high speed of rotation is lowered. Then, the rotation speed rise of a motor can be suppressed when a wheel or both wheels slip, and a safe driving operation can be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive control device for an electric vehicle, and more particularly to a drive control device for driving left and right front wheels, left and right rear wheels, and four wheels by independent motors. .

[0002]

2. Description of the Related Art An electric vehicle is one in which wheels are driven by a motor and has a schematic structure as shown in FIG. FIG.
In the configuration shown in, the left and right front wheels 1FL and 1FR have independent P
It is intended to be driven by M (permanent magnet) motors 2L and 2R, and a signal from the potentiometer 4 which is interlocked with the stroke of the accelerator pedal 3 is used as a controller C shown in FIG.
It is given as a torque command to (indicated collectively as the power supply unit 5 in FIG. 5), the inverters 6L and 6R are controlled based on the command from this controller, and the motors 2L and 2R are drive-controlled.

In the controller C shown in FIG. 6, the torque is first
A torque current command I is issued by the torque control unit C1._q ^*as well as
Excitation current command I_d ^*And the current control system C2
Current command I_q ^*And exciting current command I_d ^*And torque current
Detection value I_qAnd exciting current detection value I_dProportion and product of deviation from
By calculating the minutes, the torque voltage command V_q ^*And excitation
Voltage command V_d ^*After obtaining the
Pressure command V_u ^*, V_v ^*, V_w ^*Have gained. And this
Voltage command V_u ^*, V_v ^*, V_w ^*Inverter 6
The PM motor 2 is driven and controlled. C4 is the current
Detection value I_u, I _WTo V phase current detection value I_VSeeking
Three-phase current detection value I_u, I_v, I_wTo three-phase / two-phase conversion
The detected torque current I_qAnd exciting current detection value I_dSeeking
This is a coordinate conversion unit for Further, 7 in FIG. 6 indicates the PM motor 2.
Rotor speed detector, 8 calculates rotor position (phase) θ
Is a position detection unit, and 9 is the speed ω_rSpeed detection unit
It is.

[0004]

In the above-mentioned conventional structure, the same torque command is normally given to the left and right wheels 1FL and 1FR shown in FIG. 5, and for example, when the vehicle curves to the left, Since the load torque applied to the left wheel 1FL increases, the rotation speed of the motor 2L decreases, and the output torque of the motor and the load torque operate to balance each other. In this case, since the load torque applied to the right wheel 1FR decreases, the motor rotation speed increases and the motor output torque and the load torque operate in a balanced manner. As a result, even if the left and right wheels 1FL, 1FR are driven with the same torque command value, the wheel rotation speed on the outer wheel side becomes higher and the rotation speed on the inner wheel side becomes smaller at the time of a curve, which enables stable operation.

However, when one of the wheels slips when the vehicle is turning, the load torque of the one wheel suddenly decreases, and the motor rotation speed corresponding to the one wheel rapidly rises, resulting in a failure. Be stable. Also,
The left and right wheels of the wheels 1FL and 1FR may slip regardless of the curve of the vehicle, which is a problem even when the rotational speeds of the two-wheel motors simultaneously increase.

In view of the above problems, the present invention has an object of providing a drive control device for an electric vehicle, which suppresses an increase in the number of revolutions even if one or both wheels are slipped and the like and the number of revolutions is increased. And

[0007]

A book which achieves the above objects.
The invention has the following invention specifying matters. (1) Drive the motor by controlling the inverter with the torque command
Drive system for electric vehicles that has a system for each wheel
The difference in the detected value of the motor speed between the above systems.
If this difference exceeds a certain value, the motor rotation
The torque command value on the higher side can be subtracted according to the above difference.
And features. (2) Drive the motor by controlling the inverter with the torque command
Drive system for electric vehicles that has a system for each wheel
The difference in the detected value of the motor speed between the above systems.
If this difference exceeds a certain value, the motor speed is low.
Outputting the current control system output on the high-speed rotation side to the high-speed rotation side
It is characterized by. (3) Drive the motor by controlling the inverter with the torque command
Drive system for electric vehicles that has a system for each wheel
The detected value of the motor rotation speed changes for each system.
If the difference between the conversion rate and a fixed value is found and this difference is greater than or equal to the specified value,
To subtract the torque command of the system according to the difference
It is characterized by. (4) In (3) above, the constant value is the torque command.
Inertia J_MAnd vehicle inertia J _vTo obtain by dividing by the sum of
It is characterized by.

Even if the wheel slips or the like, it is possible to prevent an abnormal increase in the number of revolutions by suppressing the torque command and the voltage command in the control system of the wheel.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Referring now to FIGS.
An embodiment of the invention will be described. In addition, in FIGS.
6, the same parts as those in FIG.
You. 1 to 4, the controller C
The entire configuration of FIG. 6 including the outside, the inverter 6, the motor 2, etc.
Will be described as controllers X1 and X2. Figure 1
And the controllers X1 and X2 for controlling the left and right wheels respectively
The torque command T_refIs input while each control
Of the detection signals ω from the speed detectors 9 of the cameras X1 and X2_r1, Ω
_r2Is input to the adder 10 and ω_r1−ω_r2Is calculated. This
The addition result of is input to the discriminators 111 and 112.
One discriminator 111 is ω_r1> Ω _r2Δω for_r> Δω_n
It is determined whether or not ω is determined by the other discriminator 112._r1<
ω_r2Δω for_rΔω by inverting the sign of_r> Δω_n
Whether or not it is determined. Where ω_r1And ω_r2And
Δω_nWhen the above difference occurs, one of the discriminators 111
Or switch 121 or 122 with the output from 112
Will be thrown in. Of this switch 121 or 122
By inputting Δω in the multiplier 131 or 132 _rProportional to
The signal multiplied by the constant K is added to the adder 141 or 142.
Things. In addition, in the adder 141 or 142,
Command T_refTo K · Δω_rAnd subtract T_refWas'
It outputs a torque command.

In this way, a difference in motor rotational speed occurs and the difference is
Δω_nWhen it is above, for example ω _r1Is ω_r2Than Δω_n
When it becomes larger than the above, the switch 121 is closed and Δω
_r・ K is added to the adder 141 and T_ref′ = T_ref-K
・ Δω_rIs subtracted and the torque command is controlled.
It will be output to X1. Also, ω_r2Is ω_r1Than Δ
ω_nIf it is larger than that, the switch 122 will be closed.
You. As a result, the torque command on the high rotation side is reduced and
The rise of the motor rotation shaft at the time of lip can be suppressed.

FIG. 2 shows another example of the control signal switch 20.
It is provided with. That is, the controllers X1, X
2 and the detection signal ω from the speed detection unit 9_rAdder 1
Added at 0, ω_r1−ω_r2Is calculated. This value Δω_rControl
Δω at the signal switch 20_nCompared with Δω_r> 0 Δ
ω_r> Δω_nThen Δω_r<0 | Δω_r｜ ＞ Δω
_nIn this case, the voltage command is switched in each case.
That is, the control signal switch 20 includes the controller X1,
The output terminal of the current control system C2 of each X2 is its input terminal.
It is connected to the child and its output terminal is the controller X
1 and X2 are connected to the input terminals of the coordinate conversion unit C3.
It is. Then, the detected speed ω on the controller X1 side_r1Is
Detected speed ω on the controller X2 side_r2Than Δω _nGreater than
When, that is, Δω_r> 0 for Δω_r> Δω_nWhen
Release the output terminal of the current control system C2 of the tracker X1
Controller for the output terminal of the current control system of the controller X2
It is connected to each of the coordinate conversion units C3 of X1 and X2.
It is. On the contrary, ω_r2Is ω_r1Than Δω_nGreater than
When, that is, Δω_r<0 | │Δω _r｜ ＞ Δω_nWhen,
Release the output terminal of the current control system of controller X2
Controller for the output terminal of the current control system of the controller X1
It is connected to each of the coordinate conversion units C3 of X1 and X2.
It is. If such a connection state is displayed as a voltage command value,
The following expression [Equation 1] is obtained.

[0012]

[Equation 1] Thus, when the rotational speed difference Δω _r between the left and right wheels exceeds a certain value Δω _n , the current control on the high speed side is interrupted and the voltage command obtained as the current control output on the low speed side is used as the high speed side voltage command. Therefore, since the lower voltage is applied to both the left and right motors, the motors can be operated at substantially the same rotation speed. Of course, the wheel-side motor whose load torque is reduced due to the slippage has a higher rotation speed than the normal-operation side motor by a light load, but the rotation speed difference is suppressed to about Δω _n .

In this way, abnormal rotation of the one-sided motor due to slip of one wheel or the like can be suppressed, and stable operation becomes possible.

Next, another example will be described with reference to FIG. In the above description, the case where the load torque of one wheel becomes small is described, but in some cases both wheels may rotate at high speed due to slip or the like. This case and the next example (FIG. 4) describe this case. Now, when the electric vehicle is operating normally, the rotation speed ωr of the motor changes as follows. That is, when the command torque T _ref , the motor load torque (value obtained by converting the running resistance of the electric vehicle into the motor shaft) T _l , the motor inertia J _M , and the vehicle inertia (value converted into the motor shaft) J _v are given by the following equation 2].

[0015]

(Equation 2)Here, of the drive wheels, one wheel and both wheels slip.
And motor load torque T _lIs reduced and the vehicle inertia J_vBut
It will not affect the motor shaft. Generally, vehicle inertia J_vIs
Data inertia J_MSince it is about 100 times larger than
The rotation speed of the motor directly connected to the connected wheel is as follows.
You.

[0016]

(Equation 3) As a result, the rotation speed increases at 100 times or more acceleration. FIG. 3 solves this point. In FIG. 3, the detected speed ω _r of the controllers X1 and X2 is obtained as the acceleration α _w via the differentiation circuits 301 and 302. Next, in the adders 311 and 312, the acceleration α _n is the maximum rotation speed change rate of the motor when the motor is operating normally, and T ₁ = 0 T _ref is set to the maximum value T in the previous [Equation 2].
_{It is} obtained by differentiating as _{MAX and} is obtained by the following equation [Equation 4].

[0017]

(Equation 4) In this way, the outputs of the adders 311 and 312 are the outputs Δα _w of α _w −α _n , and the discriminators 321 and 322 output Δα _w.
It is determined whether or not> Δα _n . In this case, Δα _n
Is an arbitrarily set constant. When Δα _w is larger than Δα _n , that is, when the acceleration (rotational speed change) is large, the switches 331 and 332 are turned on, and Δα _w · K
The outputs of the multipliers 341 and 342 for obtaining the outputs of the above are added to the adders 141 and 142, respectively. Thus,
The torque command T _ref is T _ref −K · Δα _w T _ref ′
Will be input to the torque controller.

As a result of this, the controller X1 or X2 or X1 is caused by slipping of one or both wheels.
And the rate of change α _w of the speed ω _r of X2 increases and Δα _w > Δα
Switch 331 or 332 or 331 under the condition of _n
And 332 are turned on and the controller X1 or X2
Alternatively, the torque command T _ref of X1 and X2 decreases to T _ref ′. Therefore, the rate of increase in rotational speed is slightly higher than the maximum rotational speed change rate α _n under normal operation (α _n + Δα
_n ), and stable operation can be realized.

FIG. 4 shows another example. Instead of the maximum rotational speed change rate α _n in FIG. 3, the rotational speed change rate during normal operation at this time is used as a reference for the command torque T _ref . Is judged as abnormal. That is, α shown in the above [Formula 4]
_n is an alpha _n in T _MAX, is to determine abnormality by determining alpha _n in T _ref, i.e. T _ref in the alpha _n = T _ref / a (J _M + J _v). Therefore, in FIG. 4, the multiplier 40 is provided. The other circuits are the same as those in FIG. In this case, since α _n is determined corresponding to the torque command T _ref , a rapid increase in the rotation speed due to slip can be detected earlier, and the increase rate can be suppressed quickly.
In this way, it is possible to prevent a rapid increase in the number of revolutions due to a slip of one wheel or both wheels, etc., and stable operation becomes possible.

[0020]

As described above, according to the present invention, it is possible to suppress an increase in the rotation of the motor when the load torque is abnormally reduced in an electric vehicle, and to enable stable operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a configuration diagram of another example.

FIG. 3 is a configuration diagram of another example.

FIG. 4 is a configuration diagram of still another example.

FIG. 5 is a schematic configuration diagram of an electric vehicle.

FIG. 6 is a block diagram of a controller.

[Explanation of symbols]

 C, X1, X2 controller 1FL, 1FR wheel 2,2L, 2R motor 6,6L, 6R inverter 9 speed detector 10,141,142,311,312 adder 111,112,321,322 discriminator 20 control signal switching Unit 301,302 Differentiation circuit 40,131,132,341,342 Multiplier

Front Page Continuation (72) Inventor Takayuki Mizuno 2-17 Osaki, Shinagawa-ku, Tokyo Stock Company Meidensha

Claims (4)

[Claims] 1. A drive control device for an electric vehicle having, for each wheel, a system for controlling an inverter by a torque command to drive a motor, wherein a difference between detected rotational speeds of the motor is obtained between the systems.
A drive control device for an electric vehicle, wherein when the difference is equal to or more than a certain value, the torque command value on the higher rotation speed side of the motor is subtracted according to the difference. 2. A drive control device for an electric vehicle having, for each wheel, a system for controlling an inverter by a torque command to drive a motor, wherein a difference between detected values of the number of revolutions of the motor is obtained between the systems,
When the difference is equal to or more than a certain value, the low-speed rotation side current control system output of the motor rotation speed is also output to the high-speed rotation side. 3. A drive control device for an electric vehicle having, for each wheel, a system for controlling an inverter by a torque command to drive a motor, wherein a change rate and a constant value of a detected value of the rotational speed of the motor are set for each system. Is calculated, and when the difference is equal to or larger than a predetermined value, the torque command of the system is subtracted according to the difference. 4. The drive control device for an electric vehicle according to claim 3, wherein the constant value is obtained by dividing the torque command by the sum of the motor inertia J _M and the vehicle inertia J _v .