基于MMC的分布式潮流控制器环流抑制策略研究

Research on Circulation Suppression Strategy ofDistributed Power Flow Controller Based on MMC

在利用模块化多电平换流器来优化分布式潮流控制器的过程中,模块化多电平换流器的环流使正弦桥臂电流发生畸变,引起暂态过程不平衡扰动直接影响它的工作特性,故在基于模块化多电平换流器的分布式潮流控制器的内部数学模型基础上,提出一种抑制模块化多电平换流器内部环流的策略。灵活运用二倍频负序旋转坐标变换及解耦控制,消除环流对桥臂电流的影响,降低了功率开关器件额定电流容量,减小损耗延长装置使用寿命。仿真结果表明了此抑制策略能大幅度有效地抑制环流,并且不会对模块化多电平环流器外部输出的交流电流和电压产生不良影响。

During the process of using a modular multilevel converter to optimize the distributed power flow controller,the current in the modular multilevel converter causes the distortion of the sinusoidal bridge arm current,which results in unbalanced disturbances in the transient process,and directly affects its operating characteristics,so in the model of the distributed power flow controller based on the modular multilevel converter,a strategy to suppress the internal circulation of the modular multilevel converter was proposed.Double frequency negative sequence rotation was flexible used to coordinate transformation and decoupling control and to eliminate the impact of the loop on the arm current,reduce the power switching device rated current capacity,and reduce the loss to extend the service life of the device.The simulation results show that the suppression strategy can effectively suppress the circulation and does not adversely affect the AC current and voltage outputted by the modular multilevel converter.