飞跨电容多电平逆变器开关损耗最小PWM方法

SWITCHING LOSS MINIMIZING PWM METHOD FOR FLYING CAPACITORMULTILEVEL INVERTER

该文在理论分析的基础上建立了飞跨电容多电平逆变器载波相移PWM方法和空间矢量PWM方法之间的联系,并以此为依据,提出了飞跨电容多电平逆变器开关损耗最小PWM方法。与传统的载波相移PWM方法相比,该方法使飞跨电容多电平逆变器每相输出在一个开关周期内有120°不开关区域;根据负载的功率因数角,通过调整注入的零序电压,使120°不开关区域最大程度地位于负载电流的最大处,因此该方法大大减小了开关损耗,提高了系统的效率。仿真和实验结果证明了该方法的正确性和可行性。

A relationship between a carrier-shifting PWM and a space vector PWM in flying capacitor multilevel inverters are established, and according to the relationship, the switching loss minimized PWM for flying capacitor multilevel inverter is presented. In a comparison with conventional carrier-shifting PWM method, every phase of the flying capacitor multilevel inverter can have the 120?no switching zone in one period by the proposed method; according to power factor angle, 120° no switching zone can be adjusted to be farthest located in the centre of the peak value region of the load current through adjusting the injected zero sequence voltage, hence, the switching loss can be greatly reduced and the efficiency of the system can be greatly improved. The correctness and practicability are verified by simulation and experimentation results.