超大容量链式电池储能系统容量边界与优化设计

Capacity Boundaries and Optimization Design of Ultra-large Capacity Battery Energy Storage System Based on Cascaded H-bridge Converter

为了得到链式电池储能系统(battery energy storage system,BESS)容量设计边界与优化设计结果,分别分析了在现有功率器件容量限制、电池系统技术限制和储能系统安全性设计要求限制下,直挂35 kV电网链式BESS的容量设计边界极限。通过改变链式BESS的布置方案来抑制共模电流,并提出了链式BESS的优化设计方法;通过基于马尔可夫链的链式BESS可靠性模型来计算系统的可靠性,并对整个系统的效率与可靠性进行综合评估。研究结果表明:在现有技术条件下链式BESS最大容量设计为32 MW,改变链式BESS的布置方案能够减小共模电流引起的损耗和电流应力,保护功率器件,同时减小其对链式BESS的模块数优化设计的影响,所提优化设计方法能够根据不同应用场合下系统的设计要求得出最优的功率模块数设计。研究结果可为超大容量链式BESS的设计提供参考,也可为系统制定计划检修提供理论依据。

In order to obtain the design capacity boundaries and optimal design results of the battery energy storage system(BESS)based on cascaded H-bridge converter(CHBC-BESS)integrated into a 35 kV grid,we firstly analyze the capacity boundaries within the restraints of capacity of power devices,battery system technology and safety design of BESS separately.The suppression of common-mode current is realized by changing the layout scheme of CHBC-BESS.Then,the optimization design method of the CHBC-BESS is proposed.The reliability of the system is calculated by the Markov chain reliability model.The efficiency and reliability of the system with different modules are comprehensively evaluated.The research results show that the maximum design capacity of CHBC-BESS is 32 MW under the existing technology.Changing the layout scheme of CHBC-BESS can reduce the loss and current stress caused by the common-mode current,protect the power devices,and reduce the influence of common-mode current on the optimal design of the number of modules.By the proposed optimization design method,the optimal number of modules can be obtained according to the design requirements of system in different applications.The research results can provide references for the design of ultra-large capacity CHBC-BESS and serve as a theoretical guidance to the compilation of planned maintenance.