电网不平衡条件下模块化多电平变换器控制策略

当电网处于电压不平衡状态时,MMC的内部会产生环流.环流中存在二倍频的正序、负序和零序分量,增加了系统的不稳定性.针对电网不平衡情况下MMC二倍频环流抑制的问题,文中提出一种基于线性自抗扰控制器的环流抑制策略.根据瞬时功率理论推导出环流参数的数量关系,在此基础上设计了基于线性自抗扰控制策略的环流控制器来抑制环流.最后利...

Control Strategy of Modular Multilevel Converter Under Unbalanced Grid Voltage

When the power grid is in a voltage unbalanced state, a circulating current will be generated inside the MMC. The positive sequence, negative sequence and zero sequence components of double frequency exist in the circulating current, which increases the instability of the system. In view of the problem of MMC double-frequency circulating current suppression under unbalanced power grids, this study proposes a circulating current suppression strategy based on a linear active disturbance rejection controller. According to the instantaneous power theory, the quantitative relationship of the circulating current parameters is derived. On this basis, the circulating current controller based on the linear active disturbance rejection control strategy is designed to suppress the circulating current. Finally, the proposed control strategy is simulated by MATLAB/Simulink software. The simulation results show that the control strategy can effectively restrain the circulation and increase the stability of the system.