模块化多电平换流器直流双极短路故障耐受能力研究

针对模块化多电平换流器(modular multilevel converter,MMC)在直流侧发生双极短路的故障情况,建立了MMC闭锁后的故障电流回路,给出了二极管以及保护晶闸管的电流分配和结温理论计算方法,考核直流双极短路故障耐受能力。在MATLAB/Sinulink下进行了换流阀闭锁后故障电流回路的建模与仿真,并在MMC背靠背试验系统中进行了试验研究。仿真和试验结果表明,所提分析和计算方法准确可行,该方法对校核模块化多电平换流器在实际工程中的直流双极短路故障耐受能力以及器件选型具有重要的理论指导意义。

Current Distribution and Junction Temperature Calculation of Protective Thyristor for MMC Valve

Aiming at the fault of pole-to-pole situation in the DC side of MMC,the fault current circuit of the MMC is established and the current distribution and junction temperature calculation of the diode and protective thyristor in the MMC are given for evaluating bipolar DC short circuit fault tolerance.The model and simulation of the fault current loop of the MMC is carried out under MATLAB/Simulink,and the experiment is carried out in the MMC back-to-back test system.Simulation and experimental results show that the proposed method is accurate and effective.The proposed method has important theoretical significance for checking the tolerance of pole-to-pole short-circuit fault and device selection in practical engineering in MMC.