摘要：首先分析了传统PWM调制方式下，高速双凸极电动机在换相区和非换相区的工作模态，指出了传统PWM调制方法会出现电流上升过快，存在较大的电流纹波和转矩脉动，从而影响电机的运行特性。为此提出了在三相逆变器前级加入Buck变换器，通过转速、电感电流构成新型双闭环调速系统。理论分析和实验结果均表明，新型调速系统通过控制母线输入电压，消除了双凸极电机在非换相区内的电流纹波，有效地抑制了换相区的转矩脉动，验证了Buck变换器在系统中的有效性和必要性。

关键词：PWM控制；Buck变换器；电流纹波；转矩脉动
Abstract: First of all, the operational modes of a wound-field doubly salient machine (WFDSM) in the non-commutation and commutation regions were analyzed respectively in conventional PWM control mode. It was pointed out that the current rises excessively fast in conventional PWM modulation method. There are large current ripples and torque ripples, thus affecting the motor′s operational characteristics. Therefore, a strategy that preset a Buck converter before the three-phase inverter was put forward. The new double-loop speed control system was formed by detecting speed and inductance current. Theoretical analysis and experimental results show that, through controlling the bus input voltage, the current ripple was eliminated and the torque ripple was effectively suppressed thus verifying the authenticity and validity of the Buck converter.

Key words: PWM control; Buck converter; current ripples; torque ripples