JPH02119503A - Control device of electric rolling stock - Google Patents

Abstract

PURPOSE:To make it difficult for the slip of a part of driving wheels to develop into a slip of all the driving wheels by letting the motor current given to a current control device be the value found by the maximum value of each motor current detector resulting from multiplication by the number of motors. CONSTITUTION:In order to detect the motor current of induction motors 71 to 74 separately, current detectors 81 to 84 are provided. The current signal detected by these current detectors is inputted into a coefficient multiplier 12 by selecting the maximum value from among the signals with a maximum value selection circuit 11. It is then multiplied by the number of motors (4 sets) and fed back to a constant current controller 21. Here, let the motor current of each induction motor in normal operation be Ii(i=1 to 4), among which let the maximum value be Imax Ii. The relationship by an expression I then holds. Then, even in case the driving wheel coupled with to the 1st (i=1) induction motor slips, as the feedback signal is 4.Imax, there will be almost no change to the feedback signal with idling and less danger to the spread of slip.

Description

DETAILED DESCRIPTION OF THE INVENTION (Object of the Invention) (Field of Industrial Application) The present invention relates to a drive control device for an electric vehicle driven by an electric motor.

(Prior technology) An electric motor applies rotational force (torque) to the wheels that run on the rails to create driving wheels, and the adhesive force between the driving wheels and the rails is used to propel the vehicle by using the rotational force as propulsion force. In a car, when the rotational force exceeds the adhesive force, the driving wheels spin idle on the rails, significantly reducing the transmission of propulsion. If this phenomenon occurs while driving, it is called ``slip'', and if it occurs while braking, it is called ``sliding''. In the following text, we will explain about slipping, but since the exact same thing holds true for sliding, the explanation may be omitted.

As mentioned above, slipping occurs when the rotational force exceeds the adhesive force, but the same occurs when the adhesive force is lower than the rotational force.

When slipping occurs, the first thing that happens is that the driving force is not transmitted smoothly, but this can lead to peeling of the treads of the other driven wheels, burnout of the bearings,
Secondary problems such as rail fatigue and wear also occur. Therefore, it is necessary to control the drive so that it does not spin as much as possible.

Here, we will show an example of conventional control and point out its problems. FIG. 2 is a control block diagram showing the general configuration of a drive device installed in an electric vehicle that drives an induction motor using a PWM inverter. A current control loop is configured as shown in the figure, and a current command is given to control the torque of the electric motor to control the driving force of the electric vehicle. In the figure, 1 is a current pattern generator, 2 is a current control device, and 21 is a current command given by the current pattern generator and the detected actual motor current to control the actual motor based on appropriate control logic. A constant current controller that outputs a slip frequency command so that the current is equal to the actual current command; 3 is an adder that adds the subtraction frequency command to the motor rotation frequency to create an inverter frequency command; 4 is an adder that creates an inverter frequency command based on the slip frequency command A V/F constant controller that performs V/F constant control; 5 a PWM pulse generator that generates PWM pulses based on the voltage command that is the output of the V/F constant controller; 6 a PWM pulse generator;
A WM control voltage type inverter, 71, 72, 73, and 74 are induction lightning VJ machines, and 8 is a current detector, and the detected current is fed back to the current control section 2. 91.92.93.
94 is a speed detector. 10 is a selection circuit that selects the minimum value of speed when traveling at a constant speed and the maximum value of speed during regeneration, and the selected value is used as an adjuster 3 to create an inverter frequency command.
sent to.

When controlling the drive of an electric vehicle using this motor control system, the control logic of the current control device @2 is constant current control.
That is, the conventional method is to use the constant current controller 21. At this time, as shown in Fig. 2, one current detector 8 is installed before the circuit branches to the plurality of induction motors (four in this conventional example), and detects the sum of the motor currents of the plurality of motors. configured to detect. Therefore, the motor current signal fed back to the constant current controller 21 is also the sum of the motor currents.

Even if a current control device having such a configuration is used, there will be no problem as long as slipping or skidding does not occur. Here, we will explain the case where the vehicle spins or skids.

In addition to cases in which slipping and skidding occur in all wheels (referred to as driving wheels) connected to multiple electric motors at the same time, slipping and skidding may occur in some driving wheels. In either case, it is necessary to get the wheels out of the idling/sliding state and reattach the wheels, but this is much easier in the latter case than in the former case. However, even in the latter case, if appropriate measures are not taken promptly, all driving wheels may spin or skid. This will be explained below.

If it detects slipping or slipping by some method, it reduces the current and measures whether it will re-stick. It takes a certain amount of time to detect this slipping/skidding, so it takes a certain amount of time from when slipping/skidding actually occurs until it is detected, during which time normal constant current control continues. Ru. When slipping or skidding occurs, the motor current of the motor in question rapidly decreases. If constant current control is performed using the sum of the motor currents, this reduction will be borne by other motors that are in a healthy running state and are not slipping or skidding. In the case of slipping, the generated torque of the electric motor in a healthy running condition increases, and in the case of skidding, the control torque of the electric motor in a healthy running condition increases. I'm heading to.

(Problems to be Solved by the Invention) In the above-mentioned conventional example, there is a problem in that when some of the driving wheels idle, all of the driving wheels start idling.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems in the prior art and to provide a control device for an electric vehicle in which idling of some of the driving wheels is less likely to develop into idling of all the driving wheels.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention is a control device for an electric vehicle that controls the current of the electric vehicle with the following configuration.

It has means for giving a current command and means for detecting the current of each induction motor. r! It has a current control device that applies a P1 motor current and outputs the slip frequency of the induction motor.

As the motor current given to this current control device, a value obtained by multiplying the maximum value of each motor current by the number of motors is used.

(Function) The control device for an electric vehicle according to the present invention configured as described above performs constant current control equivalent to the conventional one during normal running, and does not require determination of slipping or skidding.

When slipping or skidding occurs, by preventing the reduced motor current of the motor connected to the driving wheel that is slipping or sliding from being borne by the motor connected to the driving wheel that is not slipping or skidding, (
The disadvantages of the prior art pointed out in the section ``Problems to be Solved by the Invention'' can be eliminated.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a drive control device for an electric vehicle including a current control device 20 for an electric vehicle according to an embodiment of the present invention.

In this figure, the same components as in FIG. 2 are given the same symbols and their explanations will be omitted.

In this embodiment, in order to detect the motor current of each induction motor individually, as shown in FIG. 1, each induction motor l! Install current detector 81.82.83.84 on one machine.

The current signals detected by these current detectors are input to the maximum value selection circuit 11, and the maximum value of these signals is selected. This selected maximum value is input to the coefficient unit 12,
The result is multiplied by the number of electric motors (4 in this embodiment) and then fed back to the constant current controller 21.

Here, the motor current of each induction motor during normal running is assumed to be tt<r=1 to 4). Assuming that the maximum value of these is Ima,x, during normal running, the variation in each current is caused by individual differences among induction motors manufactured with the same specifications, and is quite small. Therefore, the following relationship holds true.

Imax4ft (i=1 to 4; except for the motor with the maximum current) Therefore, 4. 384, the feedback signal is almost the same in both the current control device of the present invention and the conventional constant current pricking device, and during normal running, the current control device of the present invention has almost the same amount of feedback signal as in the conventional constant current control. Almost the same control behavior is obtained.

Next, consider the case where the driving wheels connected to the first (i=1> Then, the feedback signal in conventional control becomes lIIshi1 Δ11, but since there is no change in the current pattern in response to idling and constant current control is being performed, the constant current controller changes the current by this decrease Δ11. The current increases in the other three induction motors, increasing the risk of idling.On the other hand, according to the present invention, the current increases. In control, even in this case,
The feedback signal is required at 4.) max, so
There is almost no change in the feedback signal due to idling, which reduces the risk of idling spreading.

In the present invention, the signal applied to the current pattern generator 1 may be a current value given as a torque command, or a torque command may be given instead of the current command.

〔Effect of the invention〕

As explained above, the electric vehicle control device according to the present invention performs constant current control equivalent to the conventional one during normal running,
To prevent a motor connected to a driving wheel that is not slipping or sliding from bearing the reduction in motor current of a motor connected to a driving wheel that is slipping or sliding in the event of slipping or sliding, without requiring determination of whether the vehicle is slipping or skidding. Accordingly, it is possible to provide a control device for an electric vehicle in which idling of a part of the driving wheels does not easily develop into idling of all the driving wheels.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and FIG.
The figure is a block diagram showing the configuration of a conventional example. DESCRIPTION OF SYMBOLS 1... Current pattern generator, 2... Conventional current control device, 20... Current control at+ device according to the embodiment of the present invention,
21... Constant current controller, 3... Adder, 4... V/F constant controller, 5... PWM pulse generator, 6... PWM control voltage type inverter, 71.12. 7
3.74...Induction motor, 8.81.82.83.8
4... Current detector, 91.92.93.94... Speed detector, 10... Selection circuit, 11... Maximum value selection circuit, 12... Coefficient unit.

Claims (1)

[Claims of Claims] Current control that includes means for giving a current command and means for detecting the current of each induction motor, and outputs the slip frequency of the induction motor by giving the current command and the detected motor current. A control device for an electric vehicle in which a plurality of induction motors are driven by the device, wherein a value obtained by multiplying the maximum value of each motor current by the number of motors is used as the motor current given to the current control device. car control device.