JPH0755002B2 - Driving controller for electric vehicle - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a control device for a synchronous motor for an electric vehicle, which operates on the electric power of an on-vehicle battery.

[Technical Background of the Invention and Problems Thereof] In recent years, motor control technology has been rapidly advancing. For example, the development of a variable speed drive technology for a synchronous motor as shown in Japanese Patent Publication No. 59-1073 has made it possible to develop a synchronous motor. The use range of is being expanded. As one of the attempts, there is a study using a synchronous motor as a driving source of an electric vehicle.

In an electric vehicle that uses the electric power of an on-vehicle battery as an energy source, it is a major issue to extend the mileage with a limited battery capacity. In order to extend the distance that can be traveled by one charge, it is important to minimize the battery output current (discharge current) when driving the motor. Such a point is not taken into consideration at all in the conventional variable speed drive technology for the synchronous motor, and if it is directly applied to the electric vehicle, it becomes very inefficient.

[Object of the Invention] The present invention has been made in view of the above-described problems, and an object of the present invention is to control the electric power consumption of an in-vehicle battery so as to be suppressed as low as possible during traveling of an electric vehicle. An object of the present invention is to provide a travel control device for an electric vehicle capable of performing the above.

[Summary of the Invention] In order to achieve the above object, the present invention provides a synchronous motor (1) for driving wheels of an electric vehicle, and a rotational speed detecting means (2, 5) for detecting the rotational speed of the synchronous motor (1). ), An accelerator depression amount detecting means (3) for detecting an accelerator depression amount, a first processing means (4) for obtaining a torque command value based on the accelerator depression amount and the rotation speed, and a motor rotation speed and The current amplitude command value and the torque angle command value are stored in advance so as to minimize the output current of the battery in association with the torque command to the motor, and the current amplitude command value and the torque angle are based on the rotation speed and the torque command value. Second processing means (6) for obtaining a command value; current command computing means (7, 8) for computing a current command signal based on the current amplitude command value and the torque angle command value; And a conversion means (10, 11) for converting the DC power of the vehicle-mounted battery (12) into AC power based on the flow command signal and outputting the AC power to the synchronous motor (1). is there.

[Embodiment of the Invention] FIG. 1 shows a configuration of an embodiment of the present invention.
1 is a permanent magnet type synchronous motor which is a driving source of the automobile,
12 is the on-vehicle battery, 11 is the DC power of the on-vehicle battery 12, 3
Inverter for converting to phase alternating current and applying to motor 1, 10 is PWM for controlling inverter 11 by pulse width control (PWM) method
Circuit.

The current value flowing in the U phase and V phase of the motor 1 is a current sensor.
It is detected by 9a and 9b and input to the current control device 8 described later.

The position of the rotor of the motor 1 is detected by a position sensor 2 such as a resolver and input to the processing unit 5 and the processing unit 7. The processing unit 5 calculates the time change of the position θ of the motor rotor and converts it into the motor rotation speed N. The signal of the rotation speed N is input to the processing unit 4 and the processing unit 6.

An accelerator unit 3 generates a signal corresponding to the accelerator operation amount A. The signal of the accelerator operation amount A is input to the processing unit 4.

The processing unit 4 determines the torque command value T ^* for the drive system of the motor 1 based on the signal of the motor rotation speed N and the signal of the accelerator operation amount A. This processing is performed according to a map having N and A as input variables. That is, the torque command value T ^* corresponding to N and A is obtained in advance, and is mapped, and when a certain N and A are input, the corresponding T ^* is output.

The torque command value T ^* is input to the processing unit 6. The processing unit 6 determines the current amplitude command value | I | and the torque angle command value δ based on the signals of the torque command value T ^* and the motor rotation speed N. This processing is also performed according to a map created in advance.

FIG. 2 shows how to make a map in the processing unit 6. In the rotating state of the motor rotation speed N and the motor torque T at a point P on the NT plane, the current amplitude at that time
There are several combinations of | I | and torque angle δ. Among them, the combination of | I | and δ that minimizes the output current of the battery 12 is selected as the command value corresponding to the point P. In this way, for all points P in the area on the NT plane where the motor 1 can rotate, the current amplitude command value | I | and the torque angle command value δ of the combination that minimizes the battery current are obtained and mapped. . When a certain N and T ^* are input, the corresponding | I | and δ are selected and given to the processing unit 7.

The processing unit 7, based on the output value θ of the rotor position sensor 2, the current amplitude command value | I |, and the torque angle command value δ,
U-phase and V-phase current command signals I _U ^* and I _V ^* shown in the following equation are generated.

I _U ^* = | I | sin (θ + δ) I _V ^* = | I | sin (θ + δ + 2 / 3π) The command signals I _U ^* and I _V ^* are input to the current controller 8.

The current control device 8 includes a U-phase detected by the current sensors 9a and 9b,
Feedback control is performed so that the actual motor current of the V phase matches the command signals I _U ^* , I _V ^* . That is, the command signal I _U
At the same time as generating control signals I _U ^** , I _V ^** that take into account the deviation between ^* , I _V ^* and the actual motor current, I _U ^** , I _V ^** and the phase difference of 2 / 3π respectively. The W-phase control signal I _W ^** is generated and input to the PWM circuit 10.

The PWM circuit 10 converts the control signals I _U ^** , I _V ^** , I _W ^** into PWM signals and controls the inverter 11. As described above, the feed hack control works so that a current equal to the command signals I _U ^* and I _V ^* flows through the motor 1.

What should be noted here is that the current amplitude command value | I | and the torque angle command value δ that are the basis for determining the current command signals I _U ^* , I _V ^* are the corresponding motor rotation speed N and accelerator operation. This is the point that the output current of the battery 12 is the smallest among the many combinations for the quantity A.

By the way, the functions of the processing units 4, 5, 6 and 7 in the above embodiment are realized by software processing of one or more microcomputers. The processing time can be extremely shortened by performing each of the above-mentioned processes using a map, and as a result, the current command signals I _U ^* , I _V ^* have a smooth waveform close to sine. This means that highly accurate and smooth motor control can be performed.

[Effects of the Invention] As described in detail above, according to the traveling control device for an electric vehicle of the present invention, control is performed so that the output current of the battery is minimized in accordance with any rotation state of the motor. The efficiency of the drive system is improved, and it is extremely effective in extending the travelable distance with a limited battery capacity.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an apparatus according to an embodiment of the present invention, and FIG.
The figure is an illustration of how to make a map in the above embodiment. 1 ... Synchronous motor 2 ... Rotor position sensor 3 ... Accelerator unit 4-7 ... Processing unit (Function block realized by software of microcomputer)

Claims (1)

[Claims] 1. A synchronous motor (1) for driving a wheel, a rotational speed detecting means (2, 5) for detecting a rotational speed of the synchronous motor (1), and an accelerator depression amount detection for detecting an accelerator depression amount. Means (3), first processing means (4) for obtaining a torque command value based on the accelerator depression amount and the rotation speed, and an output current of the battery in association with the rotation speed of the motor and the torque command to the motor. A second processing means (6) for preliminarily storing a current amplitude command value and a torque angle command value that minimizes the current amplitude command value and the torque angle command value based on the rotation speed and the torque command value. A current command calculation means (7, 8) for calculating a current command signal based on the current amplitude command value and the torque angle command value; and a DC power of an on-vehicle battery (12) based on the current command signal. And converting means for converting the AC power output to the synchronous motor (1) (10, 11), the traveling device for an electric vehicle having a city.