A Hybrid Cascaded Power Electronic Transformer With Tight Voltage Regulation

In order to improve the efficiency and voltage regulation performance of the power electronic transformers (PETs), a hybrid cascaded PET with tight voltage regulation is proposed in this paper. In this hybrid cascaded PET, multiple LLC resonant converters and a three-level half bridge converter are employed as the isolation stage, where the LLC converter works in the dc-dc transformer mode to maximize the efficiency and the three-level half bridge dc-dc converter is used to realize the tight voltage regulation. Control strategies for the hybrid cascaded PET are proposed and a simulation model is built in MATLAB/Simulink. The simulation results verify the validations of the proposed structure and control strategies.