一种新型多电平开关变流器拓扑和控制策略研究

Research on topologies and control strategies of current source multilevel converters

论文研究了几种适用于组合式电流型多电平变流器的PWM控制方法,载波相移SPWM技术,研究了多载波PWM技术在新型单相5电平电流型逆变器中的应用,研究了SVPWM技术在三相组合型5电平CSI中应用的一些基本问题。论文提出了一类新的三相分相控制式电流型多电平逆变器拓扑。这类拓扑通过三相星形负载的中性线进行解耦,逆变器的每相都可以独立控制,因此可以将多电平PWM技术应用到该类逆变器以减小输出电流谐波。文中给出了一种多载波PWM技术的数字化实现方案,并以单相5电平逆变器单元为例介绍了三相5电平逆变器的工作原理。最后建立了一个三相分相式5电平CSI的实验系统,验证了文中的结论。

A new type of split-control three-phase 5-level CSI is proposed.The inverter is decoupled by the neutral line of the loads.Each phase of the inverter operates separately so that multilevel PWM technique can be applied.The digital current source multicarrier phase opposition disposition （POD） PWM signal generating technique is developed.The operation principle of the three-phase 5-level CSI using the new topology is introduced by analyzing one phase cell.An experimental prototype of a three-phase 5-level CSI has been built to demonstrate the proposition.Several PWM techniques applicable to combinational multilevel CSI are studied.Carrier phase-shifted SPWM technique is introduced.Multicarrier PWM method is discussed and applied to the new single-phase 5-level CSI.Some basic points about SVPWM method applied to a three-phase combinational 5-level are proposed.