The capacitor voltage balancing control strategy based on hierarchical theory in Cascaded H-bridge SSSC

Static Synchronous Series Compensator (SSSC) has great significance for improving the stability of the power grid and enhancing the transmission capability. Recently its usage has been more practical and economical by using multilevel and especially cascaded H-Bridge topologies. The modulation and control strategy based on SSSC based on cascaded H-bridge is represented in this paper firstly. However, the biggest problem of cascaded H-bridge is unbalanced capacitor voltage. Thus, an integrated capacitor voltage balancing control strategy is discussed in order to maintain capacitor voltage balance and stability. The simulation results for the capacitor voltage balance control strategy proposed in this paper verified that the ability of this method to balance the DC bus voltages.