A Compensation Scheme of Star Cascade H-Bridge STATCOM for Unbalanced Loads

Cascaded H-bridge STATCOMs are applied to medium and high voltage due to their advantages of modular structure and easy expansion. This paper focuses on the research of the three-level voltage balance control strategy for the star-connected H-bridge STATCOM, and proposes a method for calculating the reactive power reference current using the Steinmetz theorem. This method parallels capacitors or inductors on the load side in essence of topology, ultimately making the current of the load reach a three-phase balanced state. The method is applied to the star-connected H-bridge STATCOM and the simulation results validate the effectiveness of the proposed scheme.