一种新型超导储能多模块并联的电流型多电平变流器

A Novel Multi-Module Parallel Multilevel Current-Source Converter for Super-conducting Magnetic Energy Storage System

提出一种新型的超导储能多模块并联的电流型多电平变流器结构,该类拓扑结构是由多个三相六开关变流器模块和若干个分流电感组成,通过分流电感将直流侧总电流分成若干个电流等级来获得多电平的输出电流。为说明新拓扑的工作原理和结构性能,文中针对该类5电平变流器电路的开关状态、均流方法以及SPWM调制策略均进行了详细的分析。结果表明,该类拓扑具有冗余开关组合,并且变流器直流侧分流电感电流的均衡问题可以通过检测电感电流大小以及交流侧线电压极性来选择合适的冗余开关组合得以解决。文中采用载波相移SPWM技术对新拓扑进行调制,使得该类变流器在较低的开关频率下获得输出等效高频载波的效果,最后给出了该类5电平变流器的实验结果。

A novel multi-module parallel multilevel Current-Source Converter （CSC） especially applied to SMES system, is proposed. The proposed multilevel CSC structure consists of multiple modules of the current-source, three-phase six-valve converters and some current-sharing inductors which divide the dc link current into some different current scales to get multiple current levels. The 5-level main circuit is analyzed to demonstrate the performance of the novel topology. It is shown that current equilibrium problem of inductors can be resolved by detecting inductor currents and the polarity of the line to line voltages to choose appropriate redundant switching combinations. In addition, by introducing the Carder Phase-Shifted SPWM （CPS-SPWM） scheme, equivalent higher frequency carriers output can be obtained at low switching frequency of the converters. The experiment on the five-level structure gives the verification.