重载条件下无刷直流电机无位置传感器起动

Starting Method for Sensorless Brushless DC Motor Under Heavy-load Condition

针对无刷直流电机(BLDCM)重载时换相点检测不准确的问题,提出了基于直接相反电动势的起动方法。通过分析上桥臂调制下桥臂恒通(H_PWM-L_ON)方式时的端电压,建立换相期间电流变化的数学模型,根据端电压畸变的时间对端电压检测设置延时,并计算换相点的端电压阈值。电机起动时检测转子初始位置,开通相应的开关管并采样非导通相的端电压,与换相阈值比较得出换相点进行换相。利用以DSP为核心的实验平台对起动策略进行验证,实现了重载条件下电机的稳定起动。

A direct phase back electromotive force starting method is proposed to solve the problem of the inaccurate commutation point in starting of the sensorless control system of brushless direct current motors(BLDCM)with heavy-load condition.By analyzing the terminal voltage of the upper arm to modulate the low-side(H_PWM-L_ON)mode,the mathematical model of diode freewheeling current from which phase current will be turn off is established,and the terminal voltage detection delay is set according to the time of terminal voltage distortion,and the terminal voltage threshold of the commutation point is calculated.During the process of starting the motor,the initial position of the rotor is first detected.The corresponding switch tube is the corresponding switch tube is turned on and the terminal voltage of the non-conducting phase is sampled,and the commutation threshold is compared with the commutation threshold to obtain a commutation point for commutation.Using the DSP based experimental platform to verify the startup strategy,the stable start of the motor under heavy load is realized.