储能型MMC电池荷电状态均衡策略

State of Charge Balancing Strategy of MMC With Battery Energy Storage System

在储能型模块化多电平换流器(MMC)中,电池模块的差异性导致各电池模块荷电状态(SOC)不一致。为了提高电池容量利用率,需要对各电池模块的SOC均衡控制。介绍了储能型MMC的结构与原理,分析了分别基于交流功率与直流功率的三级SOC均衡方法,并对各级均衡方法进行了评估,得到了相间、上下桥臂间、桥臂内各模块间的电池SOC均衡策略,结合功率解耦控制与差分电流控制提出了系统整体控制策略。最后,搭建实验样机验证了所提均衡策略的可行性。

In energy storage modular multilevel converter(MMC),because of the inconsistency of batteries,the state of charge(SOC) of the batteries is different.In order to improve the utilization rate of battery capacity,it is necessary to balance the SOC of the batteries.The structure and principle of energy storage MMC are analyzed.The three-level SOC balance methods based on AC and DC power are analyzed.The methods are evaluated and selected SOC balance strategies among phases,upper and lower arms and each modules in one arm are obtained.With power decoupling control and differential current control,the overall control strategy is proposed.Finally,experimental prototype are built to verify the feasibility of the proposed balance strategy.