适用于模块化多电平储能变流器的分布式控制策略

摘要

分布式控制可以有效降低主控制单元的通信与运算压力,便于增强系统的扩展能力与热插拔能力.针对模块化多电平储能变流器(MM-ESC)控制系统计算量大、通信量大、整定复杂等不足,提出一种减少通信和运算的分布式控制系统架构以及适用于该控制系统的子模块荷电状态(SOC)下垂均衡控制策略.该分布式控制架构由一个中央控制单元与若干个子模块控制单元组成,中央控制单元进行交直流功率解耦控制;子模块控制单元根据本地子模块信息进行SOC下垂控制.通过分析子模块相间和相内功率差异化特性,分别设置下垂系数,从而实现子模块电池能量均衡.通过搭建五电平MMC储能变流器仿真系统以及实验平台对所述理论及控制方法进行验证,结果表明,与已有的控制系统相比,该控制架构中处理器计算量小、运行所需通信量小,同时可以满足系统运行要求.%The distributed control can effectively reduce the operation and communication pressure of the main controller and also is easy to enhance the ability of expansion and hot swap.Due to a lot of disadvantages such as the large amount of communication and calculation and complicated setting in modular multilevel energy storage converter (MM-ESC), a distributed control system architecture is proposed to reduce communication and calculation.The state of charge(SOC)droop control strategy for the control system is also discussed.The distributed control system consists of a central control unit and several submodule control units.The central control unit performs power decoupling control and sends modulated information to the submodule control units,while the submodule control units perform SOC droop control according to local information. The power difference characteristics of intra-phase and inter-phase are analyzed,and the droop coefficients are respectively set to achieve energy balance between batteries.The theory and control method are verified by a five-level MM-ESC simulation system and an experiment platform.The results show that the communication and calculation in the proposed control system are smaller than the existing control system,which can meet operation requirements.