一种新的分相控制式三相电流型五电平逆变器

A NEW SPLIT-CONTROL THREE-PHASE 5-LEVEL CURRENT-SOURCE INVERTER

在一个三相直接式多电平电流型逆变器(CSI)中利用PWM技术来消除输出电流谐波是非常困难的。文中提出了一类新的三相分相控制式电流型5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。文中以单相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。随着超导储能系统技术的发展及其应用,电流型多电平变流器将具有广泛的应用前景。

For a three-phase direct-type multilevel currentsource inverter （CSI）, it is very difficult to use PWM technique to reduce harmonic contents of the output currents. A new type of split-control three-phase 5-level CSI is proposed in this paper 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 to reduce output current harmonics. 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 practise the proposition in the paper. With the development and application of superconducting magnetic energy storage （SMES） technology, the application of multilevel CSI will be more and more popular.