一种改进的无刷直流电机无位置传感器启动控制策略

An Improved Position Sensorless Starting Control Strategy for Brushless DC Motor

针对拧紧扳手用无刷直流电机(BLDCM)无位置传感器驱动系统,研究一种改进的三段式启动控制策略。在转子预定位阶段,将电压矢量的预定位精度设置在60°范围内,同时确保通入绕组的电压脉冲占空比较低,避免电机反转。在电机加速阶段,通过分析BLDC的加速原理,结合六组加速脉冲电压矢量与六组检测脉冲电压矢量,完成稳定的闭环启动。在自同步运转阶段,当电机达到反电势可检测状态后,利用线电压差值进行反电势过零点检测,实现高精度换相。通过实验对所提出方法进行验证,结果表明改进后的三段式无位置传感器启动控制方法有较高的稳定性和转速估计精度。

Aiming at the brushless DC motor(BLDCM)sensorless driver for tightening wrenches,an improved three-stage starting control strategy was studied.In the rotor pre-positioning,the accuracy of the used voltage vector was set within the range of 60°and it was ensured that the duty cycle of the excited winding voltage pulse was relatively low so as to avoid motor reversal.During the motor acceleration process,by analyzing the acceleration principle of BLDCM,combining 6 groups of acceleration and detection pulse voltage vectors,a stable closed-loop start process was completed.In the self-synchronization region,for the back-EMF,when the motor reaches the detectable state,the line voltage difference was used to detect the back-EMF zero-crossing point to achieve highprecision commutation.Through experiments,the proposed method was verified,and the results show that the improved three-stage position sensorless start control method has higher stability and speed estimation accuracy.