“反电势法”检测无刷直流电动机转子位置的误差分析

Analysis of Shaft Position Detecting Error in a BLDC Motor with ‘Back-EMF Method’

探讨了方波无刷直流电动机采用“反电势法”检测转子关键位置时所受电枢反应的影响，推导了位置误差与电机中结构参数和工作状况的关系，证明了隐极电机转子位置的检测精度与电枢反应无关，而在凸极电机中电枢反应引起位置误差，并最终导致无刷电机超前或滞后换流。文章最后介绍了一种误差校正电路，并作了实验验证。

The key rotor position of a sensorless square-wave brushless DC (BLDC) motor can be detected with the ‘Back-EMF Method’.this paper analyzes the influence of armature reaction on the position detection, derives the relationship between position error and motor structure parameters and operating status, proves that the armature reaction does not affect the position detecting precision of a cylindrical pole BLDC motor whilst results in the position error and consequently the lead or lag commutation of a salient pole BLDC motor. Finally, the paper also presents an error-correcting circuit and its expericental results.