Many series of power conversion links in the existing power electronic transformer(PET)results in low conversion efficiency

huge volume and high cost

which restricts the practical application. Firstly

according to the mixed-frequency modulation

two novel PETs based on cascade H-bridge converter are proposed

which can reduce the number of power conversion links and achieve multiple input and output ports to improve the power density. Then

the simplified design procedure and control strategy are specifically analyzed. The Simulink is employed to verify feasibility of the proposed topologies and control strategy of PET. Moreover

the proposed topologies are compared to the existing PET topology as well.