基于单片机的无位置传感器无刷直流电机控制

摘要

Starting control and rotor position signal are the key of the normal operation for sensorless brushless DC motor ( BLDCM) . A novel control strategy of BLDCM was proposed . When the motor is still or at low speed, method of short pulse test based on the magnetic saturation effect of stator core was used to get the rotor position, and to make the motor starting. Making use of the relation of line back-EMFs and the phase commutation time, a conclusion that the phase commutation should be made at the moment of zero-crossing of line back-EMFs was drawn. According to the disadvantage of zero-crossing of line back-EMFs, the three zero-crossings of line back-EMFs were integrated into one signal, C8051F’s comparator interrupt was used to avoid the disadvantage, and position sensorless accurately commutated was achived at low cost. The control scheme can guarantee that the BLDCM reliably operates in the condition of position sensor failure or without position sensor, and the system structure is simplified, and the production cost is reduced.%起动控制和转子位置信号获取是无位置传感器无刷直流电机( BLDCM)正常运行的关键。提出了一种控制无刷直流电机的方法。在电机静止和低速运行时，利用定子电感线圈的磁饱和效应，采用短时脉冲检测法获得转子位置，实现无位置传感器的平稳起动。电机起动后，由电机线反电动势与换相时刻对应关系，得出反电动势过零时刻即为换相时刻的结论。针对反电动势过零点检测法的不足，将三路反电动势过零点信号进行整合，并利用C8051F单片机的比较中断克服其缺陷，在低成本条件下，实现无位置传感器的准确换相。该控制方案能保证BLDCM在位置传感器失效或无位置传感器的情况下可靠运行，简化了系统结构，降低了生产成本。