STATCOM compensation and control strategy of star cascade H-bridge under unbalanced conditions

According to the power compensation and control of star cascade H-bridge STATCOM under unbalanced power grid conditions, the main circuit topology is established, its equivalent mathematical model is analyzed. The AC side adopts decoupling control strategy to compensate the reactive power and unbalanced negative sequence current on the AC side of the power grid through positive and negative sequence separation. The DC side adopts three-layer voltage control strategy, that is, the overall voltage balance control of the DC side, the voltage balance control of each phase and the voltage balance control of each phase module, which solves the problem of phase to phase voltage balance on the DC side and realizes the stable operation of the system. Finally, the simulation model of the system is built in Simulink software. The results show that the proposed strategy has better compensation effect and fast dynamic performance.