Torque feedback and commutation compensation-based brushless motor control method

Abstract

The invention aims at providing a control method for a novel brushless motor to reduce torque ripples when the brushless motor runs by introducing a torque loop and a commutation compensation. According to the specific technical scheme, the method comprises the following steps: (1) determining a torque required by the motor by a difference value between a given rotating speed and an actual rotating speed; (2) determining the duty ratio by the difference value between the given torque of an outer loop and the actual torque of the motor; (3) simultaneously carrying out the step (1) and the step (2), and adopting a control strategy for switch tube lag shutdown to reduce the torque ripples caused by a commutation; and (4) driving a switch according to the duty ratio as shown in the specification obtained by a front double closed loop control algorithm and the direction of the torque. According to the method, the working range of the motor is expanded through a commutation compensation method for a lagging commutation; a neural network control algorithm used by the outer loop is quick in response, small in steady state error and small in overshoot; an inner loop utilizes a torque loop instead of a current loop, so that the control accuracy on the motor is greatly improved; and the ripples of the motor in the commutation are reduced.

Description

technical field [0001] The invention relates to a novel brushless motor control method, in particular to a brushless motor control method based on torque feedback and commutation compensation. Background technique [0002] Because the brushless motor has the advantages of both DC motor and AC motor, its structure is simple, its output is large, and its efficiency is high, so it has been used more and more in automobiles, aerospace and household appliances. However, in the process of using brushless motors, one problem that needs to be solved is torque fluctuations. There are many factors causing torque fluctuations, which can be attributed to two main reasons. One is that it is impossible to completely avoid them in the design. Cogging effect, eddy current effect and other phenomena, the second is that the brushless DC motor usually adopts electronic commutation control, and the existence of motor inductance makes the phase current impossible to be an ideal square wave. For...

AI Technical Summary

Problems solved by technology

Due to the highly nonlinear relationship between the speed and current, coupled with the current fluctuations in the commutation process, the speed control accuracy is not high and the fluctuations are large.

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