Method for optimizing DTC system of six-phase asynchronous motor

Abstract

The invention relates to a method for optimizing a DTC system of a six-phase asynchronous motor. The DTC system comprises an intermediate voltage vector selection unit, a fundamental voltage vector action time calculation unit, a speed regulator, a torque observer, a flux linkage observer, a torque hysteresis comparator, a flux linkage hysteresis comparator, a voltage 6s / 2s unit, a current 6s / 2s unit, a sector judgment unit, a space vector modulation generator and a speed measurement encoder. Compared with a traditional DTC system, intermediate voltage vectors serve as selected voltage vectors, zero vectors are evenly distributed in each switching period, and therefore current harmonics of a motor stator are improved and vector selection is simplified; the action time duty ratio of the intermediate voltage vectors in the next switching period is worked out through torque difference value variables in the current period and the moments when fundamental voltage vectors start to act are further worked out to compensate for a torque difference value, the torque ripple of the motor is reduced, and the switching frequency is kept constant.

Description

technical field [0001] The invention relates to the field of asynchronous motor control, in particular to an optimization method for a DTC system of a six-phase asynchronous motor. Background technique [0002] In recent years, in ship propulsion and other occasions that require low voltage, high current, and high reliability transmission, the application of multi-phase motor speed control systems has become increasingly widespread. Compared with the three-phase system, the multi-phase system has high reliability, can operate without phase, has small torque ripple, good dynamic and static characteristics of the system, and can realize low voltage and high power. Therefore, the six-phase asynchronous motor speed control system, as a typical multi-phase speed control system, has broad application prospects. Direct torque control (DTC) technology is another high-performance AC motor speed control method developed after vector control. DTC technology avoids complex decoupling ...

AI Technical Summary

Problems solved by technology

However, the DTC system has the problem of large motor torque ripple and stator harmonic current. The large torque ripple of the motor will affect the speed regulation performance of the motor. Additional loss, mechanical vibration and heat are the main effects of harmonics on the motor. These effects will Shorten the life of the motor, or even damage the motor

Images