DC capacitor voltage balance control of H-bridge cascaded STATCOM

The DC capacitor voltage fluctuation of H-bridge cascaded STATCOM will induce the DC voltage imbalance and influence the reliable system operation,aiming at which,the PR(Proportional Resonant) controller based on the three-level balance control strategy of DC capacitor voltage is adopted to improve the average global DC voltage control;the ADRC(Active Disturbance Rejection Controller) is applied to realize the interphase DC voltage balance control and the dynamic compensation for outside disturbance;the modulation wave of each power unit is translated to realize the in-phase DC voltage balance control and,combined with the CPS-PWM(Carrier Phase Shifting PWM),to facilitate the FPGA digital realization. Experimental results show that,being effective,the proposed control method has good dynamic performance and strong robustness.