Ripple Voltage Mitigation for Multilevel SSBC STATCOM

Performance of multilevel single-star bridge-cell (SSBC) STATCOM is affected by the low-frequency oscillation in the dc capacitors' voltages which is originated due to the double line frequency component on the absorbed active power. To avoid using big capacitors to limit this oscillation. In this paper, zero-sequence voltage injection is utilized to mitigate the oscillation and consequently improve harmonics performance in the ac side of the system. Hardware set-up using 9-level SSBC STATCOM is used to verify the results experimentally.