单相串励电动机换向过程的数值计算

Numerical calculation of commutating processes in the single-phase series-excited motor

针对换向状况恶劣的单相串励电动机,按照其实际换向结构,推导出换向片与碳刷的接触电导表达式;建立分时间段的元件换向电流的变系数微分方程组和各时间段交接处的边界值关系;就各种改善换向方法,依建立的数学模型进行换向过程数值计算,获得相应的元件换向电流波形和换向片与碳刷的接触电阻功耗曲线;通过对比分析数值计算结果,指出对改善单相串励电动机换向较为有效的措施。

Considering the commutating status of the single-phase series-excited motor, according to the commutating processes of the single-phase series-excited motor, the computational formula of the contact resistance between carbon brush and commutation segment is obtained in this paper. The time-segment commutating currents of the winding elements were expressed with variable coefficient differential equa- tions and the boundary-value relations of the junctions among the time segments were determined. For va- rious improving commutation methods, numerical calculation and analysis of the commutating process was completed based on the mathematics model of commutation, and the commutating currents of the winding elements and the average power consumption of contact resistance were accessed. The calculated results of the single-phase series-excited motor in the DC and AC conditions were compared and analyzed to se- lect the measures for improving commutation in the design of the series-excited motor.