并联多电平注入式电流源型变换器的新型拓扑

Parallel topology of multilevel reinjection current source converter

根据多电平注入交直流变换原理,设计了一种新的并联多电平注入式电流源型变换器拓扑结构,注入开关的导通电流为直流输出电流与电平数的比值。新型拓扑中每个注入支路单元由2个等效开关和1个独立电抗器构成;同一注入单元的开关交替通断;不同注入单元的开关采用状态遍历的开关控制方法,使处于通态的各单元开关平均分配直流输出电流。以三电平为例,对系统电压、电流波形及开关控制方法进行了论述,并在PSCAD/EMTDC软件环境下进行了仿真,分析与仿真结果表明了新型拓扑的良好特性。与现有的并联多电平注入式电流源型变换器拓扑结构相比,新型电路结构中注入单元开关器件的电流容量和开关通断时的电流变化率降低;各注入单元支路开关通态时间延长。

Based on the principle of multilevel reinjection AC-DC conversion, a parallel topology of multilevel reinjection current source converter is presented. Its reinjection valve currents are equal to the DC output current divided by the level numbers. Every reinjection cell consists of a reactor and two switches,turning on and off alternatively. The output DC current is equally divided by the reinjection branches by; traversal switch control method. The control method and the waveforms of voltage and current are analyzed for three -level topology,which is simulated with PSCAD/EMTDC. The results demonstrate its better performance. Compared with other parallel topologies of multilevel reinjection current source converter,the rated current of reinjection switch and its change ratio during the state transition are lower, the duty ratio of reinjection switch is higher.