JPS61293103A - Controller for vehicle - Google Patents

Abstract

PURPOSE:To improve the adhesive characteristic of a vehicle by setting the limiting value of a slip frequency in response to a vehicle speed. CONSTITUTION:A deviation amplifier 9 outputs a slip frequency command FSP in response to a deviation between a motor current I and a current command Ip. The maximum value limiter 10 limits so that the frequency fSP of a motor does not exceeds the slip frequency when a stopping torque is output. The frequency fSP and a motor rotating frequency FM are added, and an inverter frequency command FIP is applied to an inverter 2. A voltage instruction unit 11 applies a voltage command VMP for setting VMP/FIP to the prescribed value to the inverter 2. The limiting value of the limiter 10 varies in response to the frequency FM. Thus, the adhesive performance of a vehicle can be improved.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a vehicle control device that controls an induction motor for driving a vehicle using a variable voltage/variable frequency inverter (hereinafter referred to as an inverter). The present invention relates to a vehicle control device that controls an inverter when the vehicle is idling or skidding.

[Conventional technology]

BACKGROUND ART In recent years, the capacity of semiconductor elements has increased, large-capacity inverters have been put into practical use, and vehicle drive systems that drive vehicles with induction machines have been put into practical use.

Generally, the output torque (T) of an induction machine during normal acceleration is approximately expressed by the following equation (1).

T-KX (VM/Pt)"X f-...
・・・・・・・・・・・・(l》Here, K: Constant determined by the electric motor vM: Motor voltage F■: Inverter frequency fl: Slip frequency In the vehicle control system, (VM/P in the above equation (1)
Generally, the output torque of the motor is controlled by varying the slip frequency f- while keeping the value of I) at a predetermined value. However, since the following equation (2) holds true for torque, instead of commanding or detecting the included torque, the current phase ◆
Torque is indirectly controlled by matching the value (It) with the detected current value (I).

T=KX (VM/F summer) x I...
・・・・・・・・・・・・(2) P3 In C'T', VhieFx is equivalent to formula (1): Electric + fi secondary current Figure 3 shows the circuit configuration of a conventional vehicle control device It is a block diagram. In Figure 3, 1 is a DC power supply for trains, 2
is an inverter that generates a predetermined AC voltage in response to the inverter frequency index + FIPs voltage index + VMP.

3 is an induction motor, and generally a plurality of motors are connected in parallel. 4 is a pulse generator that generates a pulse train proportional to the rotation speed for detecting the rotation speed of the induction motor 3; 5 is a motor rotation frequency detector that detects the motor rotation frequency formula; and 6 is a motor current command (current command). IF)
7 is an AC current transformer that detects the motor line current (multiple AC current transformers are displayed together), 8 is a current detector that detects the motor current I, and 9 is the motor line current controller. This is a deviation amplifier that varies the slip frequency index +fsy in order to match the current command I.

10' is the maximum value limiter of slip frequency finger + fsp, 1
Reference numeral 1 denotes a voltage command device that sets the above-mentioned (VM/FI) to a predetermined value.

The limit value of the maximum value limiter 10' may be determined by using the saturation of the amplifier, or is usually determined by the slip frequency of the motor.
This is to prevent the slip frequency from exceeding the slip frequency when outputting stall torque, and the difference between the slip frequency during normal acceleration and the limit value is generally sufficiently large. f1MmX shown in the characteristic diagram of FIG. 2 is the limit value of the maximum value limiter 10' of the slip frequency, and as shown in the figure, it is a value sufficiently larger than the normal slip frequency f8.

[Problem that the invention seeks to solve]

The slip frequency fl of the electric motor is expressed by fg=+FH-PH, and the slip frequency normally matches the command value (far). If the wheels driven by this electric motor spin,
If the inverter frequency does not change, fs (by) will occur, and due to the characteristics of the induction motor, the torque generated by the wheel that has spun will decrease, making it more likely that the wheel will re-stick.

However, when controlled by the conventional circuit configuration, the current of the electric motor that drives the wheel that is spinning decreases, and in response to this, the deviation amplifier 9 adjusts the slip frequency command ◆m? , and the inverter frequency F is increased. As a result, wheels that had spun were difficult to re-stick.

An object of the present invention is to provide a control device that suppresses an increase in inverter frequency (Fl), promotes readhesion of wheels, and improves the adhesion characteristics of a vehicle.

[Means for solving problems]

In order to achieve this object, the present invention provides a vehicle control device that uses a variable voltage-variable frequency inverter to control the output torque of an induction motor for driving a vehicle. The limit value of the slip frequency is set according to the speed and speed of the vehicle.

In addition, as another embodiment of the method of setting the limit value of the slip frequency in correspondence with the vehicle speed, the above-mentioned motor rotation frequency formula or inverter frequency F is used instead of the vehicle speed to set the limit value.

This is because when the wheels are not idling, the vehicle speed is proportional to the motor rotation frequency equation, and is also approximately proportional to the inverter frequency F. Even if the wheels are idling, the motor rotation frequency formula or inverter frequency F is determined by the idling.
! This is because changes in 4 do not have much effect on the limit value of the slip frequency to be set.

In this way, the electric motor rotation frequency formula or the inverter frequency PI is used as a response to the vehicle speed, but in the detailed explanation of the present invention below, the slip frequency limit value is set in correspondence to the electric motor rotation frequency formula instead of the vehicle speed. An example of a case will be described below.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings along with their functions. FIG. 1 is a block diagram showing the circuit configuration of an embodiment of a vehicle control device according to the present invention. In the figure, the same reference numerals as in FIG. Explanation will be omitted.

IO is a slip frequency limiter whose limiter value is a value such as flL shown in the characteristic diagram of FIG. 2 in accordance with the motor rotation frequency formula.

In the case of a vehicle control device, the slip frequency f1 generally changes from a small value at low speeds to a large value at high speeds, as shown by the broken line in FIG. 2, as shown in the example in FIG. .

Therefore, in the present invention, a slip frequency limit value (fsL) is set at a value slightly larger than the normal slip frequency f1, and this value is set to be small at low speeds and small at high speeds, as shown in FIG. A slip frequency limiter 10 that changes the frequency to a large value is added.

In such a configuration, when slipping occurs and the motor current decreases by 1 Jt, the deviation amplifier 9 responds to increase the slip frequency, but the limit value fs by the slip frequency limiter 10
Since it quickly reaches L, the increase in slip frequency is suppressed and the inverter frequency F does not increase.

In this way, even if the wheel is idling, the inverter frequency F summer can be prevented from increasing, so the slip frequency of the electric motor that was driving the idling wheel becomes fs < far, and the torque generated by the idling wheel can be reduced. , promoting readhesion.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to provide a vehicle control device that improves adhesion characteristics by setting the limit value of the slip frequency according to the vehicle speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a vehicle control device according to the present invention, and FIG. 2 is a diagram showing the slip frequency limit value according to the present invention, the conventional maximum slip frequency limit value, and the limit value of the conventional IJ mitter during normal acceleration. FIG. 3 is a block diagram showing a circuit configuration of a conventional vehicle control device. 1...DC power supply, 2...Inverter, 3
...Induction motor, 4...Pulse generator, 5...Motor rotation frequency detector, 6.
...Current indicator, 7...AC current transformer, 8.
...Current detector, 9 ...Difference amplifier, 1
0...Slip frequency limiter, 10'...
・Maximum value IJ mitter, 11...Voltage indicator.

Claims (1)

[Claims] 1. In a vehicle control device that controls the output torque of an induction motor for driving a vehicle using a variable voltage/variable frequency inverter, the output torque is set to a predetermined value by varying the slip frequency of the motor. What is claimed is: 1. A control device for a vehicle, characterized in that the limit value of the slip frequency is set according to the speed of the vehicle. 2. The vehicle control device according to claim 1, wherein the control device for a vehicle is set using a motor rotation frequency or an inverter frequency as something that corresponds to the vehicle speed.