A Three-Stage Power Electronic Transformer With Time-Sharing H-Bridges

Power electronic transformer is a key apparatus in active distribution networks. It achieves power conversion and galvanic isolation. However, due to the limitation of semiconductor switches development level, most of the existing PET topologies have four or more conversion stages, which causes unsatisfying efficiencies, high costs and low power densities. A three-stage topology is proposed in which the switching device number of the primary side is decreased by half. It operates based on the time-sharing multiplexing principle. Its voltage modulation method is illustrated to analyze its power transmission capability. And its parameter design scheme and control strategy are demonstrated and verified by simulations.