A novel STATCOM based on hybrid cascade multilevel inverter

A novel static compensator (STATCOM) is proposed in this paper. The new STATCOM is constructed by a hybrid topology cascading a neutral-point-clamped (NPC) inverter and several identical H-bridge inverters. With the novel topology consisting of a same DC bus voltage but different structure modules, the realization of a multilevel converter using a hybrid approach that involves higher voltage devices and fast switch devices operating in synergism is possible. Accordingly, a hybrid modulation method for the novel inverter is proposed. By using this type of STATCOM, the bulky and weighty transformers can be eliminated, at the same time all the H-Bridge cascade inverterpsilas advantages can be kept. Furthermore, the output harmonics can be reduced by the high equivalent switching frequency. The operating principle and control methods are analyzed in detail and the feasibility is validated by simulation with MATLAB.