换向过程对直流电动机电流脉动频率影响的分析

从换向的角度对直流电动机电流脉动的原因进行了详尽的分析。认为换向造成的电流脉动除了与转速有关以外还与换向片数以及不能同时换向的电刷个数有关。电极对数影响电流脉动的原因还需从其它角度考虑。尤其在换向片数较多的电机中如何识别电刷位置偏移造成电流脉动频率的倍增或倍减，将是直流电动机无传感器测速方法要研究的难点。

Effect of Commutation Process on Current Ripple Frequency in DC Motor

The paper analyzes the frequency of the current ripple caused by the brush commutation in DC motor, and provides an analytic basis for the sensorless method to measure the DC motor speed. The frequency of the current ripple caused by brush commutation in the DC motor is determined by the number of commutator bars, the number of asynchronous commutated brushes, and the rotation speed. The reason with which the number of pole-pairs effects the frequency of the current ripple in DC motor should be found from other angles. It is the difficulty that how recognizes the false shifting of brushes by which the double increase or decrease of the current ripple frequency, especially in such motors which have more commutator bars.