模块化多电平高压直挂电池储能系统

High-voltage transformerless battery energy storage system based on modular multilevel converter

基于模块化多电平变换器(MMC)的高压直挂电池储能系统(MMC-BESS)将海量电芯分散到众多功率子模块中进行分割管控,能够克服电芯参数不一致、电池管理系统等对单机容量的限制。分析了MMC-BESS的拓扑结构、工作原理及其子模块直流侧固有的脉动电流成分,进而解析出在电池与功率子模块间引入LC无源滤波器参数对电池电流和直流侧电压成分的影响。电池和滤波电感支路接入后使得MMC-BESS相间环流产生的机理不同于传统的MMC,从理论上推导出环流与桥臂电抗和LC无源滤波器之间的耦合关系,进而提出了一种桥臂电抗和LC无源滤波器的参数设计方法。在MATLAB/Simulink中搭建了35 kV/100 MW/100MW·h的MMC-BESS,仿真结果验证了所提关键参数的设计方法及其对环流影响规律的正确性。

High-voltage transformerless battery energy storage system based on modular multilevel converter(MMC-BESS)can separate numerous battery cells into different power modules to control them independently,which can overcome the limitation of capacity of single machine due to the parameter inconsistency of battery cells and battery management system.The topology structure of high-voltage transformerless MMCBESS,working principle and the inherent power fluctuation of submodule at DC side are analyzed.On this basis,the influence of introducing the parameters of LC passive filter between the battery and the power submodule on the components of battery current and voltage at DC side is analyzed.Since the generation mechanism of interphase circulating current of MMC-BESS is different from that of the traditional MMC after introducing battery and inductance circuit,the coupling relation between LC passive filter and arm reactance is deduced.Then a parametric design method of arm reactance and LC passive filter is proposed.The correctness of the proposed parameter design method and their influence on circulating current are verified on MATLAB/Simulink by building a 35 kV/100 MW/100 MW·h simulation model.