Three-phase AC-DC-AC converter with shared legs and high-frequency link

This work proposes a multilevel AC-DC-AC converter with shared legs composed of a three-phase cell and H-bridge single-phase cells. The H-bridge cells are fed from the three-phase cell by an unidirectional converter based on high-frequency transformer. The DC-link converter solves all balancing issues, such that the proposed converter do not require DC-link voltage balancing control and the converter is able to utilize full voltage generation capability. Converter model and Space-vector pulse-width modulation (SVPWM) are presented, as well as the control strategy.