层叠式悬浮电容逆变器的新型PWM控制方法

采用多电平结构是逆变器实现高电压大容量化的有效途径。层叠式悬浮电容多电平结构可以大大减小电容器的尺寸,并且还具有控制灵活、电平数易扩展等诸多优点,因而倍受青睐,但是该逆变器也存在悬浮电容电压的平衡控制问题。据此本文提出一种新型的PWM方法,该方法不但能够有效控制电容电压的平衡,而且算法计算量小、便于数字化实现,能够保证功率器件的开关频率均衡,利用层叠式五电平逆变器,对该方法的有效性进行了详尽的仿真验证。

A Novel PWM Method for Stacked Flying Capacitor Inverter

Multi-level inverters have been considered as overall effective approach for inverter to achieve high capacity and high output voltage conversion.Allowing a significant reduction of the volume of the capacitors as well as scalable in terms of voltage levels and control flexibility,stacked flying capacitor inverter has being attracted wide industrial interests recently.But,it also needs to ensure balancing flying capacitor voltages under all operation conditions.A novel PWM method is proposed for stacked flying capacitor multi-level inverter to control the balance of flying capacitor voltages,which can be readily implemented on a digital signal processor and also guarantee the switch frequency of each switching device almost same.Validity of the method is demonstrated with extensive simulation results using a five-level stacked flying capacitor inverter.