Power stage and control design for the ETO-based cascaded-multilevel converter for FACTS applications

This paper proposes 1.5 MVA emitter turn-off (ETO) thyristor-based H-bridge building blocks (HBBB) to demonstrate the performance of the ETO and the feasibility of the cascaded-multilevel converter (CMC) for high-power applications. Several applications for the ETO-based HBBB in flexible AC transmission system (FACTS) and medium-voltage adjustable speed drive (ASD) are discussed. Three HBBB prototypes are implemented and tested. The experimental results demonstrate the potential advantages of the HBBB for the utility applications. The modeling and feedback control for the STATCOM utilizing the ETO-based three-level cascaded converter are presented. The accuracy of the corresponding model and the superior performance of the feedback controller are verified by both simulation and experimental results.