C-dump变换器开关控制方法的分析与比较

C-dump变换器是一种用于无刷直流电动机的新型功率变换器，其开关控制方式对电枢电流和变换器储能电容电压脉动有较大的影响。该文对C-dump变换器主开关和斩波开关的开关控制方式及其对电机电流和变换器储能电容电压脉动的影响进行了研究。首先对C-dump变换器主开关的PWM控制和滞环控制两种工作方式进行了比较。然后重点对斩波开关的滞环控制，斩波频率高于主开关频率的PWM控制、斩波频率低于主开关频率的PWM控制、主开关与斩开关同步PWM并结合斩波开关滞环控制等5种开关控制方法进行了详细的理论分析与比较。结果表明：主开关与斩波开关同步PWM并结合斩波开关滞环控制可较好地减小储能电容电压和电机电流脉动，有利于改善系统性能。最后进行了仿真与实验验证。

ANALYSIS AND COMPARISON ON THE CONTROL STRATEGY OF THE C-DUMP CONVERTER

The C-dump converter is a new type of power converter used in brushless DC motors, and its switchingcontrol strategies have a major effect on the armature currents ripple of the motor and the voltage fluctuation of the energy recovery capacitor in the converter. This paper is devoted to investigating the switching control strategies and their effects on the motor system. The two switching control strategies, PWM control and hysteresis control, for the main switches in the converter are discussed. In particular, several switching control strategies for the chopping switch are analyzed and compared in detail, including the hysteresis control, the PWM control with higher or lower switching frequencies than those of the main switches, the synchronous PWM control with main switches, and the synchronous PWM control combined with the hysteresis control. The synchronous PWM control combined with hysteresis control is recommended for the C-dump converter due to its small current ripple of the motor andvoltage fluctuation of the energy recovery capacitor. The results of the numerical simulation and experiments have demonstrated the effectiveness of the recommended switching controlstrategy.