电力电子变压器并联环流成因与抑制方法  

Cause and Suppression Method of Circulating Current for Parallel Operation of Power Electronic Transformer

作　　者：王宁 王珍珍 张建忠[1] WANG Ning;WANG Zhen-zhen;ZHANG Jian-zhong(Southeast University,Nanjing 210096,China;不详)

机构地区：[1]东南大学电气工程学院,江苏南京210096 [2]国网天津市电力公司营销服务中心,天津300202

出　　处：《电力电子技术》2022年第12期21-24,共4页Power Electronics

摘　　要：针对中点箝位型(NPC)三电平变换器的电力电子变压器(PET)结构及其并联运行下的功率分配方式,分析了并联PET系统环流通路与成因,建立了PET间交叉环流的数学模型,指出了滤波电感差异和交流侧电压差异对环流大小的影响。为减小环流,提出了一种基于叠加补偿电流的环流抑制控制策略,实现了不同参数PET间环流的有效抑制。最后,通过实验验证了所提控制策略的可行性。The parallel operation of power electronic transformer(PET) can effectively improve the redundancy,reliability and expansibility of distribution system.But the inconsistency of parameters and capacity will lead to circulating current and increase the current stress of switching devices and converter loss.According to the structure of the PET based on the neutral point clamped(NPC) three-level converter and the power distribution method of the parallel system,the path and the cause of the circulating current of the paralleled PET system are analyzed.The mathematical model of the cross circulating current between PET is established.The influence of inductance difference and AC side voltage difference on circulating current is pointed out.A circulating current suppression strategy based on additional compensation current is proposed to reduce circulating current of parallel PET with different parameters.Finally,the feasibility of the proposed strategy is verified by experiments.

关 键 词：电力电子变压器 功率分配 环流抑制 

分 类 号：TM4[电气工程—电器]