Device and method for direct torque control of permanent magnet synchronous motor

Abstract

The invention relates to a device and a method for direct torque control of a permanent magnet synchronous motor, belonging to the technical field of alternating current motor transmission. The device comprises the permanent magnet synchronous motor, a signal detecting circuit, a processor and an inverter. A current signal and a direct current bus voltage signal of the permanent magnet synchronous motor are respectively output to the signal detecting circuit which transmits the signals to the processor for processing so as to obtain a switch signal which is transmitted to the inverter for controlling the motor. According to a stator flux linkage amplitude error and an electromagnetic torque error, the device and the method respectively estimate a reference voltage vector in a stator rotating coordinate system, then convert the reference voltage vector into a stator biphase static coordinate system, and finally utilize a space vector modulation method to generate the switch signal for the inverter so as to control the permanent magnet synchronous motor. The device and the method adopt the space vector modulation method and substitute a proportional controller for a conventional hysteresis comparator so as to effectively reduce the pulsating movement of flux linkage and torque. The method adopted for voltage vector estimation is simple so that the structure of the control system can be simplified and easily realized.

Description

technical field [0001] The invention belongs to the technical field of AC motor transmission, in particular to a direct torque control device and method of a permanent magnet synchronous motor. Background technique [0002] Direct torque control is a high-performance AC speed control strategy. It was first proposed by Germany's Depenbrock and Japan's Takahashi for the application of asynchronous motors, and then ABB introduced corresponding products in the 1990s. In 1997, Professor Rahman of the University of New South Wales in Australia introduced the direct torque control method into the permanent magnet synchronous motor (PMSM). [0003] The conventional direct torque control method of the permanent magnet synchronous motor adopts the torque hysteresis comparator and the flux hysteresis comparator, according to the position of the stator flux linkage, selects the appropriate voltage vector from the switch table to control the flux linkage and torque . Since there are on...

AI Technical Summary

Problems solved by technology

Since there are only 8 voltage vectors to choose from, the selected voltage vector cannot meet the dual requirements of the system for flux linkage and speed at the same time, which will cause large torque and flux fluctuations in the motor system; in addition, the hysteresis comparator will The switching frequency of the system is not constant

In recent years, the space vector modulation (SVM) method has been introduced into direct torque control, such as the patent ZL 200710019081, but the voltage estimation method used is relatively complicated

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