模块化多电平换流器电容电压平衡并行排序方法

Parallel Sorting Method for Capacitor Voltage Balancing of MMC

针对模块化多电平换流器(MMC)存在的电容电压均衡问题,从实际工程出发,采用了一种基于现场可编程逻辑门阵列(FPGA)的并行全比较电容电压实时排序算法。基于RT-LAB在环半实物仿真平台进行了实验。结果表明,该算法实现了电容电压的排序并行处理,排序运算只需要4个时钟的运算时间,且运算时间不随桥臂子模块数量而变化,达到了实时性排序的效果。此外,该算法遵循了避免不必要的开关动作的原则,降低了器件的开关频率和开关损耗。

It is difficult to solve the problem of voltage balancing among the sub-modules（SM）, thus, we adopted a kind of parallel full comparison capacitor voltage real-time sorting algorithm based on FPGA from actual engineering standpoint. Based on RT-LAB, we conduct experiments on a loop semi-physical simulation system. The results show that the algorithm can realize the sort parallel technology of capacitor voltage with only four-clock operation time and the computation time does not vary with the number of sub-modules, so that real-time effect is good. Moreover, the algorithm follows the principles of avoiding unnecessary switch action that can reduce the switching frequency of devices and the switching loss.