JP3149682B2 - Electric car control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electric vehicle, and more particularly, to the detection of slipping and skidding.

[0002]

2. Description of the Related Art In a railway vehicle, torque is transmitted to a rail by friction between a driving wheel (a wheel for transmitting power to the rail) and the rail to perform acceleration / deceleration, and F is applied to a driving wheel circumferential pulling force (or Brake force), W is the weight on the driving wheel,
An expected friction coefficient (adhesion coefficient) of μ = F / W is obtained,
Normally, since the friction coefficient between the driving wheel and the rail is larger than μ obtained by the above equation, no slip or gliding occurs, but when the friction coefficient becomes low due to rainfall, the value of μ obtained by the above equation becomes smaller. Becomes large, causing slip and gliding.

[0003] Now, let us consider that an idle wheel has occurred. As shown in FIG. 5 , the running wheel in which the slip occurs, that is, the slip axis speed 5 rotates at a higher acceleration than the running wheel in which the slip does not occur, that is, the acceleration of the train speed 1, and therefore, by monitoring the acceleration, Idling detection can be performed.

[0004] When a railway vehicle travels, mechanical vibrations are generated on a bogie having many spring systems due to irregularities on the rail surface, distortion in the left-right direction, irregularities on the wheel treads, and the like. In addition, mechanical play such as a bending joint and a gear device causes amplification of vibration, and the vibration is transmitted to the drive motor.

[0005] This phenomenon also occurs during low-speed running, and it is known that large vibrations are transmitted to the drive motor especially when passing through rail joints and turnouts. Of these vibrations, the vibration component generated in the shaft rotation direction of the drive motor will change the shaft rotation speed, so be careful in inverter-controlled electric vehicles that monitor the motor rotation speed and detect idling / sliding. is necessary. That is, FIG. 6 (a)
As shown in (b), when the motor rotation speed change due to these vibrations is detected, even though the electric vehicle is not actually spinning / sliding, the detection of idling / sliding is performed. This is because the operation becomes unnecessary for detection.
Therefore, the set value of the detection is determined so as not to respond to the change in the rotational speed due to the vibration in the rotation direction of the motor shaft, and to be able to detect normally when idling / sliding occurs.

FIG.6(A) Superimposition of vibration on motor speed 2
Is the same as train speed 1
In the case of, the rotation speed change value for idling detection 3, unit for idling detection
Unnecessary operation of detection even if interval 4 is set as shown
But it does not6(B) shows the variation in motor speed 2
This shows the case where the motion is superimposed.6
(A) Same idling speed change value 3 for idling detection
If the setting time is set to 4, the unnecessary operation of detection may occur.
Are shown.

When the train runs at high speed, the above-mentioned vibration tends to increase due to mechanical resonance or the like.

To solve this problem, Japanese Patent Application Laid-Open No. 62-160001 discloses that the detection level (set value) of slip / skid is increased with an increase in the speed of an electric vehicle.

[0009]

In the above-mentioned prior art, the slip / slide detection level is increased with an increase in the speed of the electric vehicle. Therefore, when an actual slip / slide occurs, a large slip / slide detection level is required. There is a problem that the idling / sliding state is not detected until the acceleration reaches, and the idling / sliding state is continued for a long time.

An object of the present invention is to reduce erroneous detection due to vibrations other than slipping / sliding, and to detect slipping / sliding in a short period of time.

[0011]

The above object is achieved by increasing the time for calculating the rate of change of the motor speed as the speed of the electric vehicle increases.

[0012]

As described above, the amplitude of the vibration such as mechanical resonance superimposed on the motor speed increases as the speed of the electric vehicle increases. However, since the resonance frequency does not change much, if the time for calculating the rate of change of the motor speed is constant, and if the values of the valleys and peaks in the half cycle of the vibration are sampled, the calculation is performed from that value. The resulting change rate increases as the electric vehicle speed increases.
In the above prior art, the slip / slide detection level is increased according to the speed of the electric vehicle. However, as described above, the detection of the true slip / slide is delayed.

Therefore, by increasing the time for calculating the rate of change of the motor speed in accordance with the increase in the speed of the electric vehicle, the influence of mechanical resonance on the calculation of acceleration is reduced. For example, if the valleys and peaks of one and a half cycles of the vibration are sampled instead of the valleys and peaks of the half cycle of the vibration, the calculated acceleration is smaller than that of the calculation of the half cycle.

As described above, although the detection is delayed by the lengthening of the calculation cycle, the erroneous detection can be reduced as much as possible without changing the original detection accuracy of the slip / skid.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

An AC induction motor (not shown) is used as a drive motor, and a variable voltage / variable frequency inverter (not shown) is used.
A description will be given of an example of control in a VVVF inverter-controlled electric vehicle controlled by the above. In the block diagram of FIG.
A signal from a PG sensor 6 attached to an induction motor (not shown) is input to a motor speed detector 7, and the motor speed is input to a maximum / minimum selector 9. The maximum / minimum selection section 9 selects and outputs the minimum value of the input motor speed during power running and the maximum value during regeneration (braking). This is based on the idea that the motor outputting the minimum value does not run idle during power running, and conversely, the motor outputting the maximum value does not slide during regeneration. This value is used as feedback motor speed 10 to create inverter frequency 20.

On the other hand, an unillustrated U-phase V-phase W-phase motor current of an induction motor is detected by a motor current detector and output to an effective value calculation unit 12. The effective value calculator 12 calculates the motor current effective value 13 and outputs a current feedback value. The deviation between the motor current effective value 13 and the motor current command 14 is input to the current control unit 15, and a slip frequency correction value 16 is output so that the motor current effective value 13 follows the motor current command 14. The slip frequency correction value 16 and the slip frequency command 17 are added to output a slip frequency 18, which is added to or subtracted from the feedback motor speed 10.
9, damping control is performed and the inverter frequency 2
Get 0. The inverter (not shown) is subjected to pulse width modulation control based on the inverter frequency 20 and an inverter output voltage command calculated based on the inverter frequency 20.

The drive induction motor is connected to wheels (both not shown) via a flex joint and a gear unit. If the mechanical play of the flex joint and the gear unit is neglected, the motor rotational speed is reduced. Detecting is the same as detecting the number of rotations of the wheels. Therefore, a change in the number of motor revolutions per unit time is calculated from the detected number of revolutions of the motor, and when the value becomes equal to or greater than a preset value (set value), an idling detection signal is output (see FIG. If the idling detection unit 21) in 3 is provided, the idling can be easily detected.

FIG. 2 shows the configuration of the idling detection section 21. The idling detection unit 21 is provided for each shaft of the motor, and the motor rotation speed 8 of each shaft output from the motor rotation speed detection means 7 is stored in the ring buffer 24. Motor speed F (0) currently input and motor speed F before unit time T for detection
The rotation speed change value is obtained by subtracting (−T) using the rotation speed change value calculation unit 27. The change rate is calculated by inputting the value ΔF to the change rate calculation unit and calculating ΔF / T. When the comparator 30 detects that this value exceeds a predetermined value (set value) K, the idle rotation /
Detects gliding.

As described above, since the amplitude of the resonance of the mechanical system tends to increase as the train speed increases, erroneous detection of idling increases as the speed increases. Therefore, in the present embodiment, the detection value calculation unit 34
The unit time T for calculating the rotation speed change rate is increased according to the speed, and this value is output to the rotation speed output unit 250 and the change rate calculation unit 252, and the change rate is calculated based on the unit time T. Calculate.

[0021] will be described with reference to FIG. 4 this state. FIG. 4 is a graph in which the mechanical resonance (motor rotation speed) is superimposed on the train speed. However, the mechanical system resonance is exaggerated to facilitate understanding.

The unit time T when the electric vehicle speed is low is T
If it is 1, β1 / T1 is the rate of change α1 of the rotation speed.
If the calculation of the change rate is not changed even when the electric vehicle speed is increased, the change rate α1 is increased by the increase in the amplitude of the mechanical system resonance. In the above-mentioned prior art, the set value K is increased in accordance with the speed, but the sensitivity of the slip / slide detection is reduced and the original slip / slide cannot be detected. In this embodiment, this problem is solved by increasing the unit time T to T2 as the electric vehicle speed increases. That is, as shown, the unit time T is T2
By doing so, the effect of mechanical system resonance is reduced. Comparing the case where the unit time T is T1 and the case where the unit time T is T2, although the amplitude of the mechanical resonance is large,
It can be seen that the change rate α has not changed much. As described above, in the present embodiment, simply changing the unit time T according to the speed minimizes the influence of mechanical system resonance on the slip / slide detection and minimizes the set value K. The slide detection sensitivity does not change.

By the way, when the calculation of the change rate is performed by using the division as in the above embodiment, the detection of the slip / skid is delayed due to the relation of the calculation speed. For this reason, β, which is usually the output of the subtracter 27, is directly input to the comparator 30 and compared with the set value K to make the idle rotation
Running detection is performed. In this case, even if there is no mechanical system resonance, if the unit time T is increased, β which is the output of the subtracter 27 increases according to the train speed. For this reason, there occurs a problem that the electric vehicle acceleration exceeds the set value in a high speed range. To solve this problem,
In the present embodiment, utilizing the fact that the acceleration of an electric vehicle is substantially constant for each electric vehicle, the unit time T is increased in accordance with the speed and the set value K is increased in proportion to the change in the unit time T. I did it. Hereinafter, description will be made with reference to FIG.

The difference from the embodiment shown in FIG. 2 is that two types of slip / slide detection are provided to detect slip / slip which is a phenomenon, and that the unit time and set value for each are changed according to the speed of the electric vehicle. The point is to make it happen. The reason for using two types of slip / slip detection is that if the slip acceleration is relatively high and there is a risk of developing a large slip phenomenon, a detection with a large rotation speed change value and a short detection unit time ( For idling phenomena that cannot be detected by the detecting means that the idling acceleration is relatively low and the idling acceleration is relatively low, the detection of a relatively small rotation speed change value and a relatively long unit time of detection is performed (26, 28, 31). 29 and 32).

In order to change the idling detection set value according to the train speed, the idling detection section 21 is added with a detection value calculation section 34 as a function for outputting the detected set value.

The detection value calculation unit 34 inputs the normalized motor rotation frequency 10 (the real electric vehicle speed may be detected using the shaft rotation speed of the trailer vehicle without using the motor rotation speed). The unit time calculation units 35 and 36 correspond to the motor rotation frequency 10, that is, the train speed, and the detection unit times 25 and 26, and the rotation speed change value calculation unit 3
7, 38 output the rotational speed change set values 28, 29. FIG. 3 shows that two sets of variables are output for each of the unit time of detection and the set value. However, as described above, this is because the idling detection unit 21 has a configuration having two-stage detection means. It corresponds to what has become.

The purpose of the present invention is to prevent unnecessary operation of idling / sliding detection due to vibration in the rotating direction of the motor shaft during high-speed running. Therefore, the system corresponding to the detection signal 31 in FIG. The time T1 is set to be long. Furthermore,
As the unit time T1 for detection is increased, the set value K1 is also increased. This means that, as described above, if only the detection unit time T1 is lengthened and the set value K1 is kept the same, the detection sensitivity does not decrease as shown in FIG. 5 but increases as the train speed. This is in order to prevent the detection operation from easily occurring. The same applies to the unit time T2 and set value K2 of the other system.

Further, motor rotation frequency at the inflection point shown in the arithmetic unit 35 to 38 in FIG. 3, the function of the words speed V1, V2, and the setting value corresponding to the speed, electric performing the control Depending on the characteristics of the vehicle, it can be set arbitrarily through a current vehicle test or the like.

Although the method of detecting slip has been described above, the principle of the method of detecting skidding is the same, except that the direction of acceleration is reversed (deceleration).

When slipping / sliding is detected based on the above principle, readhesion control is executed. This will be described with reference to FIG. When a slip / slide occurs, the slip detection unit 21 outputs a slip / slide detection signal to the re-adhesion control unit 23 and the latch 22. The latch 230 in the readhesion controller 23 latches the value of the slip frequency at that time. On the other hand, when the idling / sliding detection signal is input, the latch 22 is switched to the re-adhesive switching device 4.
0 is switched from b to a side. The slip frequency latched by the latch 230 is subtracted by a predetermined value fs0 and input to the high-order selection unit 232. Based on this output, an inverter frequency is created, and further input to the latch 230, where a predetermined value fs0 is subtracted. This state continues until the slip frequency becomes 0 or the slip / slide ends.

As described above, when the idling / sliding is detected, the readhesion control system operates to reduce the torque of the driving motor. In such a case, the reduced electric braking force is covered by the air braking, which causes a problem of causing abrasion of the brake disk, deterioration of ride comfort, and the like. According to the present embodiment, erroneous detection due to resonance of the mechanical system is reduced, and idling / sliding that requires re-adhesion control is reliably detected, so that unnecessary torque shortage and brake wear are reduced. The effect is that it can be prevented.

[0032]

According to the present invention, even when the vibration in the rotation direction of the motor shaft increases according to the speed, unnecessary operation for detecting idling / sliding does not occur, and good speed control of the electric vehicle can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing an embodiment of an idling detection unit.

FIG. 3 is a diagram showing another embodiment of the slip detection unit.

FIG. 4 is a diagram showing the principle of the present invention.

FIG. 5 is a diagram showing a behavior of a motor rotation speed when idling occurs.

FIG. 6 is a diagram illustrating a case where vibration is not superimposed on a motor rotation speed;

[Explanation of symbols]

1: Train speed, 2: Motor rotation speed, 3: Detection speed setting value, 4: Detection unit time, 5, Spindle speed, 6: PG
Sensors, 7: Motor rotation speed detecting means, 8: Motor rotation speed of each axis, 9: Maximum / minimum selection unit, 10: Normalized motor rotation speed (feedback motor rotation speed), 11: Motor current detector, 12 ... Effective value calculation unit, 13 ... Electric motor current effective value, 1
4 ... Motor current command, 15 ... Current control unit, 16 ... Slip frequency correction value, 17 ... Slip frequency command, 18 ... Slip frequency, 19 ... Damping control unit, 20 ... Inverter frequency, 21 ... Slip detection unit, 22,230 ... Latch, 23
... Re-adhesion control unit, 24 ... Ring buffer, 25,26,
250 unit time for detection, 27, 231 subtractor, 2
8, 29, 253: set value, 30: comparator, 31, 32
... Detection signal, 33 ... OR logic, 34 ... Detection value calculator, 3
5, 36 unit time operation unit, 37, 38 set value operation unit, 40 re-adhesion changeover unit, 232 high order selection unit
251, a motor rotation speed current value output unit; 252, a change rate calculation unit.

──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Masato Iwataki 1070 Ma, Katsuta-shi, Ibaraki Hitachi, Ltd. Mito Plant (72) Inventor Yuji Sasanuma 1070 Ma, Katsuta-shi, Ibaraki Hitachi, Ltd.Mito Plant, Hitachi, Ltd. (56) References JP-A-1-222602 (JP, A) JP-A-63-186503 (JP, A) JP-A-62-160001 (JP, A) JP-A-61-142902 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) B60L 3/00-3/12 B60L ^7/ 00-7/28 B60L 11/00-11/18 B60L 15/00-15/38

Claims (2)

(57) [Claims] 1. A control device for an electric vehicle, comprising: a slip / slide detecting means for detecting a slip or a skid when a change in a rotation speed of a main motor per unit time becomes larger than a predetermined value. An electric vehicle control device including means for increasing the unit time as the speed of the electric vehicle increases . 2. The system according to claim 1, wherein the idling / sliding detecting means increases the predetermined value as the speed of the electric vehicle increases.
A control device for an electric vehicle, comprising: