无传感器无刷直流电机变负载运行的控制方法

为了使无位置传感器无刷直流电机能够在变负载情况下正常起动,提出一种新的控制方法.该方法利用电机在定电流情况下起动时,每个换相间隔内开关占空比逐渐减小的特性来判断电机转子是否旋转到位,从而实现电机闭环起动.为了减小电机在自然换相过程中产生的转矩脉动,在PWM_ON调制模式和反电势法控制的基础上,通过抑制换相时电机中点电压波动来抑制电机转矩脉动.实验结果表明,使用该控制方法后,电机能够在负载变化的情况下正常起动,转矩脉动也得到有效地抑制.

Control method of sensorless brushless DC motor in load variation condition

This paper proposes a novel control method to start the sensorless brushless DC motor in the load variation condition. When the motor starts to move in the given current condition, the duty cycle decreases in each commutation interval, and using which it can roughly determine if the rotor has been moved to the specified location. In order to reduce the torque ripple during the natural commutation, this paper presents a low cost method to change the duty ratio during commutation, based on the PWM_ON modulation and back-EMF control method. Experimental results show that the motor can start normally in the load variation condition and the torque ripple has also been effectively suppressed using the proposed methods．