基于波动功率传递的MMC型固态变压器子模块电容优化方法  

MMC-based Solid State Transformer’s Submodule Capacitance Optimization Method Based on Fluctuation Power Delivery

作　　者：周剑桥 王晗[1] 张建文[1] 蔡旭[1] 施刚[1] 章一新 ZHOU Jianqiao;WANG Han;ZHANG Jianwen;CAI Xu;SHI Gang;ZHANG Yixin(Wind Power Research Center,Key Laboratory of Control of Power Transmission and Conversion(Shanghai Jiao Tong University),Ministry of Education,Minhang District,Shanghai 200240,China)

机构地区：[1]风力发电研究中心,电力传输与功率变换控制教育部重点实验室(上海交通大学),上海市闵行区200240

出　　处：《中国电机工程学报》2020年第12期3990-4003,共14页Proceedings of the CSEE

基　　金：国家自然科学基金项目(51877136);上海市科委科研计划项目(19DZ1205403);2019台达电力电子科教发展计划青年项目(DREG2019012)。

摘　　要：基于模块化多电平换流器的固态变压器(modular multilevel converter based solid state transformer,MMC-SST)由模块化多电平换流器和多个双有源桥变换器(dualactive bridge,DAB)组成,是实现交直流混合配电网柔性互联及多端潮流控制的关键装置。MMC-SST子模块电容较大,制约了装置功率密度的提升,影响了其在配电网的应用。该文提出一种基于波动功率传递的MMC-SST子模块电容优化方法及控制策略,该方法将电容电流中的低频成分传递到DAB低压侧,以降低子模块电容电压波动,从而优化电容容值。同时,量化分析了波动功率传递对DAB器件参数的影响,并对比了优化前后的功率密度。针对MMC-SST的仿真与实验结果表明,采用电容优化方法,子模块电容容值可减小为常规方法的15%,MMC子模块和DAB单元的整体功率密度提高了104%,满足MMC-SST在配网中应用的紧凑化设计要求。Modular multilevel converter based solid state transformer(MMC-SST),which consist of MMC and dual active bridge(DAB),is a key equipment to achieve energy router in AC/DC hybrid distribution system.The internal submodule capacitors in MMC-SST restrict the power density improvement.This paper proposed a capacitance optimization method for MMC-SST based on fluctuation power delivery.This method delivered the low frequency component of capacitor current to the DAB side,which could reduce the capacitor voltage fluctuation.The basic operation principle of MMC-SST was firstly introduced.Then,the feasibility of capacitance optimization based on fluctuation power delivery was analyzed in theory.On this basis,the novel control strategy of MMC-SST was proposed.At last,considering the influence of fluctuation power delivery,the DAB internal high frequency transformer was redesigned,and the effectiveness of this method on improving MMC-SST submodule’s power density was evaluated.Simulation and experiment results based on MMC-SST case verify the feasibility of this method:capacitor voltage fluctuation could be mitigated.Therefore,the redesigned capacitance could be reduced to 15%,and the submodule power density could be improved by 104%.

关 键 词：波动功率传递 模块化多电平 双有源桥变换器 固态变压器 电容优化 

分 类 号：TM41[电气工程—电器]