基于降阶谐振控制器的MMC不平衡控制策略

摘要

Control strategy of modular multilevel converter(MMC) under unbalanced grid voltage is presented.The pulsation of instantaneous power is analyzed based on the mathematical model of MMC.Then with the proportional-integral plus reduced order resonant (PI-ROR) controller,the multi-target unbalanced control of MMC is realized without the positive and negative sequence separation.By the ROR controller,the circulating current is also suppressed.Finally,utilizing the three-phase experimental prototype,the proposed control system is verified.The experimental results prove the feasibility of the control system.%主要研究了模块化多电平变流器(MMC)在电网三相不平衡条件下的控制策略.建立MMC数学模型,分析在不平衡电网下瞬时功率脉动;采用比例-积分降阶谐振(PI-ROR)控制器,无需对电流正负分离,实现对MMC多目标的不平衡控制,在此基础上依然通过ROR控制器进行不平衡电网下MMC环流抑制.最后利用实验对所提控制算法进行了验证,实验结果证明了其可行性.