面向百兆瓦级应用的电池储能系统拓扑与控制方法

Topology and Control Method of Battery Energy Storage System for Application at the Scale of Hundreds of Megawatts

随着新能源占总装机的比重不断提高,电池储能电站的容量和规模不断扩大,提升电池储能系统(battery energy storage system,BESS)单机容量具有重要的工程实践意义。为探究面向百兆瓦级应用更具优势的BESS拓扑,首先,分析了传统集中式BESS存在的问题及其单机电压等级和容量提升受限的原因;然后,通过计算分析了星型结构、三角形结构和模块化多电平结构3种高压直挂式BESS的单机容量;最后,以星型结构为例,展开详细研究。介绍了星型结构的拓扑结构和数学模型,分析了高压直挂式BESS的控制方法,包括网侧功率控制和荷电状态均衡控制。通过搭建35 kV/10 MW的仿真模型,验证了控制方法的有效性。研究结果表明,高压直挂式BESS在单机容量和扩容方面具有明显优势,更适用于高压、大容量的应用场合。

With the increasing proportion of new energy in the total installed capacity,the capacity and scale of battery storage power stations are expanding.The improvement of unit capacity of battery energy storage system(BESS)has important engineering practical significance.To explore the BESS topology with more advantages in the face of the development trend of large capacity and large-scale battery storage power stations,the paper first analysed the problems of the traditional centralized BESS and the reasons why the voltage level and capacity of the single machine are limited.Then,the single unit capacity of three kinds of high voltage transformerless BESS was analysed through calculation,i.e.the star structure,triangle structure and modular multilevel structure.After that,the star structure was taken as an example to carry out a detailed study.The topological structure and mathematical model of star structure were introduced,and the basic control strategies of high voltage transformerless BESS were analysed,including the power control at the grid side and state of charge equalization control.The effectiveness of the control strategies was verified by 35 kV/10 MW simulation model.The research results show that the high voltage transformerless BESS has obvious advantages in single machine capacity and capacity expansion,and is more suitable for high-voltage,high-capacity applications.