JPH11355916A - Controller for electric car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable slip detection of a driving wheel, and enable slip reduction and acceleration control as well, by providing a slip detecting means which detects the current to voltage ratio of a motor. SOLUTION: A battery voltage Vb to be detected from a battery 1 through a key switch 4 and an input circuit 17, and a motor current Im to be detected with a current sensor 10 through an input circuit 18, are found. Besides, the voltage Vm of a running motor is found by multiplying the duty factor Dm of a chopper of a chopper transistor 14 by the battery voltage Vb. And it is judged that a slip has occurred, when the ratio Im/Vm of the motor current Im to the motor voltage Vm is smaller than a specified value. Consequently, it becomes possible to detect a slip of a driving wheel, and to perform slip reduction and acceleration control in accordance with road conditions, a car weight, and the difference of a car, and wear reduction of the driving wheels and enhancement of drivability are realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle control device such as a battery forklift, and more particularly to an electric vehicle control device suitable for detecting slip of drive wheels or reducing slip.

[0002]

2. Description of the Related Art A conventional device for detecting a slip of a driving wheel is disclosed in Japanese Patent Application Laid-Open No. Hei 3-60302, for example, by detecting a difference in rotation between a driving wheel and a driven wheel. , The vehicle speed change rate was detected.

A conventional device for reducing the slip of a driving wheel is disclosed in Japanese Patent Publication No. 62-60887 and Japanese Patent Application Laid-Open No. 8-116606, in which the amount of increase in current and duty ratio is determined according to a predetermined pattern. Had control.

[0004]

In the above prior art, it is necessary to provide a sensor or the like for detecting the rotational speed of the driving wheel or the driven wheel in order to detect the slip of the driving wheel. For this reason, there has been a problem of an increase in cost due to the addition of the sensor and its wiring and input circuit. Further, in order to reduce the slip of the drive wheels, it is necessary to set a plurality of patterns of the increase amount of the current and the duty ratio by experiments and calculations according to the assumed road surface condition, vehicle weight, and the like. In particular, in a vehicle such as a forklift, in which the load on the same vehicle significantly changes the vehicle weight due to the load, or the load on the drive wheel decreases in spite of the increase in the vehicle weight due to the load, the conditions to be assumed are as follows. Because of the variety, setting the pattern was quite difficult. Also,
If the number of patterns and set values are inappropriate, the expected slip reduction effect may not be obtained, or slip once stopped may recur during acceleration, so it takes time and effort to find patterns. And of course, every time the vehicle changed, the pattern had to be reset. An object of the present invention is to make it possible to detect a slip of a drive wheel based on data that can be detected inside a control device without adding a sensor or the like for detecting the rotation speed of a drive wheel or a driven wheel or a vehicle speed to a vehicle. In addition, an object of the present invention is to provide an electric vehicle control device that enables slip reduction and acceleration control according to road surface conditions, vehicle weight, and differences between vehicles, and thereby reduces driving wheel wear and improves driving operability. .

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides means for detecting a ratio between a current of a motor and a voltage of the motor, or an amount of change in a ratio of a current of the motor to a voltage of the motor. Means for detecting, or means for detecting the ratio between the amount of change in the current of the motor and the amount of change in the voltage of the motor,
Or means for detecting the ratio between the current of the motor and the duty ratio of the chopper, or means for detecting the change in the ratio between the current of the motor and the duty ratio of the chopper, or One of the means for detecting the ratio of the flow rate to the change amount is provided in the slip detecting means, and the driving force limiting means for limiting the driving force of the electric motor when the slip is detected by the slip detecting means. .

Further, means for detecting a current of the electric motor when the slip is detected by the slip detecting means, means for setting a current limit value based on the detected current value, and a chopper within a range not exceeding the current limit value. And a means for controlling the flow rate of the driving force.

Further, the driving force limiting means includes means for temporarily setting the flow rate of the chopper to a predetermined value when the slip is detected by the slip detecting means.

[0008] A rotational speed detecting means for detecting the rotational speed of the electric motor, and means for inhibiting the operation of the driving force limiting means when the slip detecting means detects a slip and the rotational speed is equal to or more than a specified value. It is provided with.

Further, the rotation speed detecting means is configured to determine the rotation speed as a function of the voltage of the motor, the current of the motor, and a preset characteristic characteristic of the motor.

Further, there is provided means for obtaining the voltage of the motor by multiplying the power supply voltage by the chopper conduction ratio.

Assuming that the current of the motor is constant, the higher the rotation speed, the higher the voltage of the motor. Conversely, assuming that the voltage of the motor is constant, the higher the rotation speed, the lower the current of the motor. Therefore, in the case of the driving motor, the current of the driving motor increases as the vehicle weight increases and the rotation speed does not increase. That is, the voltage Vm of the driving motor
Can be said to correspond to the vehicle weight. When Im / Vm (vehicle weight) becomes smaller (lighter) than a value corresponding to the weight when the vehicle is empty, it is determined that a slip has occurred. Similarly, when the vehicle weight suddenly decreases from the change amount of Im / Vm, it is determined that a slip has occurred. Here, in order to judge that a slip has occurred, an accurate value such as how many kg is not necessary,
It is sufficient if the magnitude of the vehicle weight or a change in the vehicle weight can be relatively determined. Therefore, it is not necessary to add a sensor for detecting the rotation speed of the drive wheel or the driven wheel or the vehicle speed to the vehicle, and the drive wheel is detected based on Im / Vm which can be detected inside the control device without increasing the cost. Can be detected.

Further, since the current of the motor is correlated with the torque and the voltage of the motor is correlated with the rotation speed, a slip is generated when the rotation speed is greatly increased despite the small increase in the torque, and the change in the motor current is changed. If the ratio dVm / dIm of the change amount dVm of the voltage of the electric motor to the amount dIm exceeds a specified value, it is determined that a slip has occurred. Also in this case, it is sufficient that the change in the torque and the change in the rotation speed can be relatively determined. Therefore, it is not necessary to add a sensor for detecting the rotational speed of the drive wheel or the driven wheel or the vehicle speed to the vehicle, and the drive wheel is detected based on dVm / dIm which can be detected inside the control device without increasing the cost. Can be detected.

Incidentally, when a microcomputer is used, the above-mentioned Im / Vm, dVm
/ DIm may be calculated as Vm / Im and dIm / dVm, respectively, and the object can be similarly achieved by appropriately setting a specified range for determining occurrence of slip.

The voltage Vm of the motor is equal to the power supply voltage Vb.
Is multiplied by the chopper conduction ratio Dch. Since the ratio dependent on Dch is larger than Vb, Vm
The same result can be obtained by using Dch instead of. D
When the channel is used, the accuracy is slightly lower than the detection based on Vm, but it is sufficient to detect only a slip on an extremely slippery road surface such as an icy road, which is effective for simplifying the configuration. Also in this case, it is not necessary to add a sensor for detecting the rotational speed of the driving wheel or the driven wheel or the vehicle speed to the vehicle, and the cost of the motor Im and the chopper current can be detected inside the control device without increasing the cost. Flow rate Dc
Based on h, the slip of the drive wheel can be detected.

Further, the driving force limiting means detects the current of the electric motor at the time of occurrence of the slip, thereby relatively detecting the torque at which the slip occurs in the road surface condition and the vehicle weight at that time. Then, based on the detected value, a current limit value corresponding to a torque at which a slip does not occur is set, and if the chopper conduction rate is reduced so as to be equal to or less than the current limit value, the slip stops and the current limit value is exceeded. If the chopper flow rate is increased within a non-existent range, acceleration control will be performed so that slip does not recur.

As described above, since the acceleration (torque) is set in accordance with the road surface condition and the vehicle weight when the slip occurs, the vehicle weight changes greatly depending on the load, or the vehicle weight increases due to the load. In spite of this, it is possible to cope with a vehicle in which the driving wheel weight is reduced in reverse, and it is not necessary to previously set a plurality of patterns of the increase amount of the current and the duty ratio (chopper conduction ratio) by experiments and calculations. Since it is not necessary to reset the pattern even when the vehicle changes, time and labor can be saved, and the slip of the driving wheels and the acceleration control can be controlled according to the road surface condition, the vehicle weight, and the difference between the vehicles.

However, on a very slippery road surface such as an icy road, if the delay time from the occurrence of slip to the start of the chopper control by the above current limit value is long, the rotation speed of the driving wheels increases during that time, which is expected. In some cases, a reduced slip reducing effect cannot be obtained. Therefore, the operation of the above-described means for once setting the chopper flow rate to a predetermined value when a slip is detected, first stops the slip, and then prevents the slip from occurring again (so as not to exceed the current limit value). By performing the chopper control, it is possible to surely reduce the slip even on an extremely slippery road surface such as a frozen road.

In the case where the range of slip detected by the slip detecting means is set wide (for example, not only on extremely slippery road surfaces such as frozen roads, but also on road surfaces where sand floats on asphalt). ), When the vehicle accelerates again from a situation in which the vehicle is coasting (eg, depressing the accelerator),
It is determined that slip has occurred because the vehicle weight has become lighter or the rotational speed has greatly increased with a small torque, and a state in which the torque is limited by the driving force limiting means occurs. Depending on the vehicle, the acceleration feeling may be degraded by the operation of the driving force limiting means.
Therefore, when the rotation speed of the electric motor at the time of slip detection is equal to or more than the specified value, the operation of the driving force limiting means is prohibited, thereby preventing the acceleration feeling from deteriorating when the vehicle is running by inertia.

Further, by configuring the rotation speed as a function of the voltage of the motor, the current of the motor, and a preset characteristic characteristic of the motor, the rotation speed of the motor can be detected inside the control device. Can be obtained based on

Depending on the configuration of the control device, the power supply voltage may be easier to detect than the voltage of the motor.
In this case, provision of means for obtaining the voltage of the electric motor by multiplying the power supply voltage and the chopper conduction ratio facilitates slip detection and slip reduction based on data that can be detected inside the control device.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric vehicle control device according to the present invention will be described in detail with reference to the illustrated embodiments.

FIG. 1 is a circuit diagram of an embodiment of the present invention. In FIG. 1, 1 is a battery, 2 and 3 are fuses, 4 is a key switch, 5 is a constant voltage circuit, 6 is a ROM,
7 is a microcomputer, 8 is a flywheel diode, 9 is a plugging diode, 10 is a current sensor, 11 is a driving motor, 11a is an armature winding, 11b is a field winding, 12 is a forward contactor, 12a
Is a forward contactor coil, 13 is a reverse contactor, 13
a is a reverse contactor coil, 14 is a chopper transistor, 15 is an accelerator, 16 is a forward / reverse selector switch, 1
7, 18, 19, 20 are input circuits, 21, 22, 23 are output circuits, 24 is a forward contactor drive transistor, 2
Reference numeral 5 denotes a reverse contactor driving transistor.

Next, the operation of this embodiment will be described.

First, when the key switch 4 is turned on, the constant voltage circuit 5 operates and power is supplied to the microcomputer 7. The microcomputer 7 starts processing according to a program stored in the ROM 6 in advance.

Hereinafter, the processing by the microcomputer 7 will be described with reference to the flowchart shown in FIG.

When the processing by the microcomputer 7 is started, first, an initial setting processing 101 is executed.

Next, in the input process 102, the battery voltage Vb detected from the battery 1 via the fuse 3, the key switch 4 and the input circuit 17 and the motor current V detected from the current sensor 10 via the input circuit 18 Im,
An accelerator signal Acc detected from the accelerator 15 via the input circuit 19 and a forward / reverse signal FRSW detected via the input circuit 20 from the forward / reverse selector switch 16 are input.

Subsequently, a slip detecting process 103, a rotational speed detecting process 104, a driving force limiting process 105, and a running control process 106 are sequentially executed.

Finally, according to the key switch detecting process 107, while the key switch 4 is ON, the input process 102 is executed.
The subsequent steps are repeatedly executed, and the process ends when the key switch 4 is turned off.

The operation of the slip detection process 103 will be described with reference to FIGS. 3, 4, 5, 6, 7, and 8.

FIG. 3 shows the motor current Im and the motor voltage Vm.
9 is a flowchart in the case of detecting a slip from the ratio of.

First, in the motor voltage calculation processing 201, the traveling motor voltage Vm is obtained by multiplying the chopper conduction ratio Dm by the battery voltage Vb. Next, in the slip determination process 202a, the motor current Im and the motor voltage Vm
If the ratio Im / Vm is smaller than the specified value, it is determined that a slip has occurred, and in step 203, a slip occurrence flag SLIP is set.

FIG. 4 shows the motor current Im and the motor voltage Vm.
9 is a flowchart in the case of detecting a slip from the amount of change in the ratio of the slip.

First, the running motor voltage Vm is obtained by the motor voltage calculation processing 201 as in FIG. Next, in the slip determination process 202b, the previous motor current Io
When the difference between the ratio Io / Vo of the motor current Vo and the ratio Im / Vm of the current motor current Im and the motor voltage Vm is greater than a specified value, it is determined that a slip has occurred. Is set. Thereafter, in step 204b, I
m / Vm is stored as Io / Vo.

FIG. 5 is a flowchart in the case of detecting a slip from the ratio between the amount of change in the motor current Im and the amount of change in the motor voltage Vm.

First, the running motor voltage Vm is obtained by the motor voltage calculation processing 201 as in FIG. Next, in the slip determination process 202c, the current motor voltage Vm
Between the current and the previous motor voltage Vo and the current motor current Im
Of the difference between the previous motor current Io and the previous motor current Io (Vm−Vo) /
If (Im-Io) is larger than the specified value, it is determined that a slip has occurred, and in step 203, the flag SLIP is set.
Is set. Thereafter, in the process 204c, Vm and Im are stored as Vo and Io, respectively, for the next determination process.

FIG. 6 is a flowchart in the case of detecting a slip from the ratio between the motor current Im and the chopper conduction ratio Dm. Compared to FIG. 3, the processing is simplified because there is no motor voltage calculation processing 201.

In the slip determination process 202d, it is determined that a slip has occurred when the ratio Im / Dm between the motor current Im and the chopper conduction ratio Dm is smaller than a specified value.
In step 203, the flag SLIP is set.

FIG. 7 is a flowchart in the case of detecting a slip from the amount of change in the ratio between the motor current Im and the chopper conduction ratio Dm. Compared to FIG. 4, the processing is simplified because there is no motor voltage calculation processing 201.

First, in the slip determination process 202e, the difference between the ratio Io / Do between the previous motor current Io and the chopper conduction ratio Do and the ratio Im / Dm between the current motor current Im and the chopper conduction ratio Dm is calculated. If the value is larger than the specified value, it is determined that a slip has occurred.
Set the flag SLIP. Thereafter, in a process 204e, Im / Dm is changed to Io / D for the next determination process.
Store as o.

FIG. 8 is a flowchart in the case of detecting a slip from the ratio of the amount of change in the motor current Im to the amount of change in the chopper conduction ratio Dm. Compared to FIG. 5, the processing is simplified because there is no motor voltage calculation processing 201.

First, in the slip determination process 202f, the ratio (Dm-Do) of the difference between the current chopper conduction ratio Dm and the previous chopper conduction ratio Do and the difference between the current motor current Im and the previous motor current Io. If the value of (/ Im-Io) is larger than the specified value, it is determined that a slip has occurred, and in step 203, the flag SLIP is set. Then, in process 204f, D
m and Im are stored as Do and Io, respectively.

By using any of the slip detection processes of FIGS. 3, 4, 5, 6, 7, and 8, any one of the chopper conduction ratio Dm, the battery voltage Vb, and the motor current Im can be used. Also determines the occurrence of slip based on data that can be detected inside the control device.

Next, the operation in the rotation speed detection processing 104 will be described with reference to the flowchart shown in FIG.

First, in a coefficient setting process 301, a rotation speed calculation coefficient Km is set from a motor current Im by a coefficient setting function f1. FIG. 10 shows the characteristics of the coefficient setting function f1. This characteristic is set in advance by calculation from the output characteristic of the motor.

Next, in the rotation speed calculation process 302, the motor rotation speed Nm is calculated from the coefficient Km obtained in the above process and the chopper conduction ratio Dm, the battery voltage Vb, the motor winding resistance Rm, and the motor current Im. I do. Here, Rm is
This is a constant preset as data unique to the motor.

As described above, the motor rotation speed Nm is determined based on the data which can be detected in the control device in any of the chopper conduction ratio Dm, the battery voltage Vb, and the motor current Im, and the preset data unique to the motor. It has been calculated.

FIG. 1 shows the operation in the driving force limiting process 105.
1 will be described.

When the vehicle is stopped, the flag SET has been cleared by a traveling control process 106 described later. Since the flag SLIP is also cleared when the slip does not occur, the process 405 is executed according to the determination of the processes 401 and 402, and the maximum current value Imax determined from the allowable current of the chopper transistor 14 is set as the current limit value Is. Is set. Next, in process 409, the duty ratio limit value Dd is set to 100%.

Even when the vehicle is running, if the slip does not occur, the same processing as in the above-mentioned vehicle stopped state is performed.

When a slip occurs and the flag SLIP is set by the slip detection processing, processing 402 is executed.
The process 403 is executed according to the determination of. Motor rotation speed N
If m is less than the specified number of revolutions, the process 404 is executed based on the determination in the process 403, and a current value of 80% of the motor current Im is set as the current limit value Is. Next, processing 40
6,407,408, the chopper flow rate Dm is 5
When it is 0% or less, the flow rate restriction value Dd is set to 0%, and when Dm exceeds 50%, Dd is Dm-50%.
Is set to

When the flag SET is set in the process 410, the process 40 is executed next time by the judgment in the process 401.
9 is executed. Therefore, processes 403, 404, and 40
6, 407 and 408 are executed only when a slip occurs during running. The operation in the traveling control processing 106 will be described with reference to the flowchart shown in FIG.

First, processing 501, 502, 503, 50
By 4, switching control of the forward / backward contactors 12 and 13 is performed. If the forward / reverse signal FRSW is forward, an ON signal is output to the forward contactor drive port FC. The forward contactor drive transistor 24 is turned on by the output ON signal via the output circuit 22, the forward contactor coil 12a is energized, and the forward contactor 12 is turned on. When the FRSW is in reverse, an ON signal is output to the reverse contactor drive port RC. With the output ON signal, the reverse contactor drive transistor 25 is turned on via the output circuit 23, the reverse contactor coil 13a is energized, and the reverse contactor 13 is turned on. When the FRSW is neutral, an OFF signal is output to the FC and the RC, and the current limit value Is and the duty ratio set value Ds are set to 0,
Clear the flag SET.

Next, in step 506, the duty ratio setting value Ds is calculated from the accelerator signal Acc by the duty ratio setting function f2.
Set. FIG. 13 shows the characteristics of the conduction ratio setting function f2.

Next, in the feedback process 507, as shown in the flow chart of FIG. 14, the chopper duty ratio Dm is equal to the duty ratio set value Ds or the duty ratio until the motor current Im reaches the current limit value Is. Dm is increased so as to be the smaller of the limit values Dd. Im
Reaches Is, control is performed so that the increase of Dm is stopped and Im does not exceed Is, even if Dm has not reached Ds or Dd.

Next, in a chopper signal output process 508, an ON / OFF signal corresponding to the chopper conduction ratio Dm is output to the chopper signal output port CH. The output chopper signal drives the chopper transistor 14 via the output circuit 21.

Thus, during normal driving (SET = 0,
SLIP = 0, Is = Imax, Dd = 100%)
As long as the motor current Im does not exceed the maximum current value Imax, the conduction ratio set value D set from the accelerator signal Acc
The chopper flow rate Dm is set according to s, and acceleration control is performed.

When a slip occurs (SET = 0, SL
IP = 1, Is = 80% of Im, Dd = 0% or Dm
-50%) stops the slip of the driving wheels by limiting the current limit value Is to 80% of the motor current Im at that time and temporarily lowering the chopper duty ratio Dm to the duty ratio limit value Dd.

Further, during acceleration after the occurrence of slip (SET =
1, SLIP = 1, Is = 80 of Im when slip occurs
%, Dd = 100%), the chopper flow rate D once decreased
m is a conduction ratio set value D set by the accelerator signal Acc.
Until s is reached, the current is gradually increased within a range not exceeding the current limit value Is, and acceleration control is performed while preventing recurrence of slip.

According to this embodiment, a sensor for detecting the rotational speed of the driving wheel or the driven wheel or the vehicle speed is not added to the vehicle, and any one of the chopper conduction ratio Dm, the battery voltage Vb, and the motor current Im is used. Also makes it possible to detect drive wheel slip based on data that can be detected inside the control device, and to enable slip reduction and acceleration control according to road surface conditions, vehicle weight, and vehicle differences, and as a result, drive wheel wear Reduction and improvement in driving operability can be realized.

[0061]

According to the present invention, a sensor for detecting the rotational speed of the drive wheel or the driven wheel or the vehicle speed is not added to the vehicle, and the slip of the drive wheel is performed based on the data which can be detected inside the control device. Can be detected, and slip reduction and acceleration control can be performed according to road surface conditions, vehicle weight, and differences in vehicles, and as a result, wear of drive wheels can be reduced and driving operability can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of an electric vehicle control device according to the present invention.

FIG. 2 is a program flowchart in one embodiment of the present invention.

FIG. 3 is a program flowchart of a slip detection process 103 based on a ratio between a motor current Im and a motor voltage Vm in one embodiment of the present invention.

FIG. 4 is a program flowchart of a slip detection process 103 based on an amount of change in a ratio between a motor current Im and a motor voltage Vm in one embodiment of the present invention.

FIG. 5 is a program flowchart of a slip detection process 103 based on a ratio between a change amount of the motor current Im and a change amount of the motor voltage Vm in one embodiment of the present invention.

FIG. 6 shows a slip detection process 10 based on the ratio between the motor current Im and the chopper conduction ratio Dm in one embodiment of the present invention.
3 is a program flowchart of FIG.

FIG. 7 is a program flowchart of a slip detection process 103 based on an amount of change in the ratio between the motor current Im and the chopper conduction ratio Dm in one embodiment of the present invention.

FIG. 8 is a program flowchart of a slip detection process 103 based on a ratio between a change amount of the motor current Im and a change amount of the chopper conduction ratio Dm in one embodiment of the present invention.

FIG. 9 is a rotation speed detection process 10 according to an embodiment of the present invention.
4 is a program flowchart of FIG.

FIG. 10 illustrates a coefficient setting function f1 according to an embodiment of the present invention.
FIG.

FIG. 11 shows a driving force limiting process 1 according to an embodiment of the present invention.
It is a program flowchart of 05.

FIG. 12 is a traveling control process 10 according to an embodiment of the present invention.
6 is a program flowchart of FIG.

FIG. 13 is a flow rate setting function f according to an embodiment of the present invention.
2 is a characteristic diagram of FIG.

FIG. 14 is a program flowchart of a feedback process 507 in one embodiment of the present invention.

[Explanation of symbols]

1 ... battery, 2,3 ... fuse, 4 ... key switch,
5: constant voltage circuit, 6: ROM, 7: microcomputer, 8: flywheel diode, 9: plugging diode, 10: current sensor, 11: drive motor, 1
1a ... armature winding, 11b ... field winding, 12 ... forward contactor, 12a ... forward contactor coil, 13 ... reverse contactor, 13a ... reverse contactor coil, 14 ... chopper transistor, 15 ... accelerator, 16 ... forward / backward Changeover switch, 17, 18, 19, 20 ... input circuit, 2
1, 22, 23 ... output circuit, 24 ... forward contactor drive transistor, 25 ... reverse contactor drive transistor, 101 ... initial setting processing, 102 ... input processing, 103
... Slip detection processing, 104 ... Rotation number detection processing, 105 ...
Driving force limiting processing, 106: travel control processing, 107: key switch detection processing.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroyuki Yamada 2477 Takaba, Hitachinaka-shi, Ibaraki Prefecture Inside Hitachi Car Engineering Co., Ltd. (72) Inventor Shigeru Kuriyama 2477 Takaba, Hitachinaka-shi, Ibaraki Corporation Sawa Service Co. (72) Inventor Minoru Kanaga 2520 Takaba, Hitachinaka City, Ibaraki Prefecture Inside the Automotive Equipment Division of Hitachi, Ltd.

Claims (19)

[Claims] An apparatus comprising: means for chopper-controlling an electric motor for driving a vehicle; and slip detection means for detecting slip of a drive wheel, wherein the slip detection means comprises:
An electric vehicle control device comprising: first means for detecting a ratio between a current of the electric motor and a voltage of the electric motor. 2. The slip detecting means according to claim 1, wherein said slip detecting means determines that a slip has occurred when a value detected by said first means exceeds a specified range. An electric vehicle control device, comprising: a driving force limiting means for limiting the driving force of the electric motor when the detection is made. 3. An apparatus having a means for chopper-controlling an electric motor for driving a vehicle and a slip detecting means for detecting a slip of a driving wheel, wherein the slip detecting means comprises:
An electric vehicle control device comprising a second means for detecting an amount of change in a ratio between a current of the electric motor and a voltage of the electric motor. 4. The slip detecting means according to claim 3, wherein said slip detecting means determines that a slip has occurred when a value detected by said second means exceeds a specified range. An electric vehicle control device, comprising: a driving force limiting means for limiting the driving force of the electric motor when the detection is made. 5. An apparatus comprising: means for chopper-controlling an electric motor for driving a vehicle; and slip detection means for detecting slip of a drive wheel, wherein the slip detection means comprises:
An electric vehicle control device comprising: third means for detecting a ratio between a change amount of a current of the electric motor and a change amount of a voltage of the electric motor. 6. The slip detecting means according to claim 5, wherein said slip detecting means determines that a slip has occurred when a value detected by said third means exceeds a specified range. An electric vehicle control device, comprising: a driving force limiting means for limiting the driving force of the electric motor when the detection is made. 7. An apparatus comprising: means for chopper-controlling an electric motor for driving a vehicle; and slip detection means for detecting slip of a drive wheel, wherein the slip detection means comprises:
An electric vehicle control device comprising: fourth means for detecting a ratio between a current of the electric motor and a conduction ratio of the chopper. 8. The slip detecting means according to claim 7, wherein said slip detecting means determines that a slip has occurred when a value detected by said fourth means exceeds a specified range. An electric vehicle control device, comprising: a driving force limiting means for limiting the driving force of the electric motor when the detection is made. 9. An apparatus comprising: means for chopper-controlling an electric motor for driving a vehicle; and slip detecting means for detecting slip of a driving wheel, wherein the slip detecting means comprises:
An electric vehicle control device comprising: fifth means for detecting an amount of change in a ratio between a current of a motor and a flow rate of the chopper. 10. A slip detecting means according to claim 9, wherein said slip detecting means determines that a slip has occurred when a value detected by said fifth means exceeds a prescribed range.
An electric vehicle control device comprising: a driving force restriction unit that restricts a driving force of the electric motor when a slip is detected by the slip detection unit. 11. A device having a means for controlling a motor for driving a vehicle by a chopper and a slip detecting means for detecting a slip of a driving wheel, wherein the slip detecting means comprises: An electric vehicle control device, comprising: a sixth means for detecting a ratio of the duty ratio to a change amount. 12. The slip detecting means according to claim 11, wherein said slip detecting means determines that a slip has occurred when the value detected by said sixth means exceeds a specified range. An electric vehicle control device, comprising: a driving force limiting means for limiting the driving force of the electric motor when the detection is made. 13. An apparatus having chopper control means for an electric motor for driving a vehicle and slip detection means for detecting slip of a drive wheel, wherein a current of the electric motor when the slip detection means detects a slip is detected. An electric vehicle comprising: means for detecting; means for setting a current limit value based on the detected current value; and means for controlling the duty ratio of the chopper within a range not exceeding the current limit value. Control device. 14. An electric vehicle control apparatus according to claim 13, further comprising means for temporarily setting a flow rate of said chopper to a predetermined value when a slip is detected by said slip detecting means. 15. The driving force limiting device according to claim 2, wherein said driving force limiting means detects a slip by said slip detecting means. Means for detecting the current of the motor, means for setting a current limit value based on the current detection value, and means for controlling the duty ratio of the chopper within a range not exceeding the current limit value. Electric vehicle control device. 16. The apparatus according to claim 15, wherein said driving force limiting means includes means for temporarily setting a flow rate of said chopper to a predetermined value when a slip is detected by said slip detecting means. Electric car control device. 17. A rotation speed detecting device for detecting the rotation speed of the electric motor according to claim 2, claim 4, claim 6, claim 8, claim 10, claim 12, claim 15, or claim 16. And a means for prohibiting the operation of the driving force limiting means when the slip is detected by the slip detecting means and the rotational speed is equal to or more than a specified value. 18. The apparatus according to claim 17, wherein said rotation speed detecting means determines the rotation speed of said motor as a function of the voltage of said motor, the current of said motor and a preset characteristic characteristic of said motor. An electric vehicle control device characterized by being performed. 19. The power supply voltage according to claim 1, claim 2, claim 3, claim 4, claim 5, claim 5, claim 16, claim 16, claim 17, or claim 18. An electric vehicle control device comprising: means for detecting; and means for obtaining a voltage of the electric motor by multiplying the power supply voltage by a conduction ratio of the chopper.