基于线反电动势的无刷直流电机无位置传感器控制

A Position Sensorless Control Strategy for BLDCM Based on Line Back-EMF

提出了基于线反电动势的转子位置检测策略,以实现无刷直流电机的无位置传感器控制。通过分析无刷直流电机线反电动势与换相时刻对应关系,得出线反电动势过零时刻即为换相时刻的结论。然后,检测两路线电压和相电流并计算得到线反电动势,进而重新安排换相条件来给出六个换相时刻。在此基础上通过分析线反电动势的计算值与换相时刻的对应关系,采用相移补偿策略来补偿由于滤波引起的误差。相比于相反电动势法,系统减少了一路信号检测电路,不需要移相。仿真和实验结果显示该策略能够准确地给出换相时刻,避免了传统反电动势法在移相过程中带来的误差。

A novel rotor position detecting method based on line back electromotive force （back-EMF） is proposed to implement brushless DC motor （BLDCM） position sensorless control. Rounded analysis is done to draw conclusion that the phase commutation should be made at the moment of zero-crossing of line back-EMF. Line back-EMFs are obtained by sampling two line voltages and phase currents. The commutation points are settled by rules different from existing ones. The phase delay of filtered line EMFs is considered and compensated by using advanced conduction. Finally, simulation and experimental results are given, from which it can be seen that the correct time of commutation points are exactly decided and the phase-shafting error is avoided that occurs when ordinary back-EMF method is used. Additionally, the system is verified to be simplified because it needs less voltage detecting circuit.