In order to make power electronic transformer(PET) apply to high voltage and high power situation, a circuit structure of high voltage stage consisted of cascaded H bridges and low voltage stage consisted of parallel H bridges is proposed, which could improve the voltage and current class. The operation principles and topology of the system are described and analyzed and control strategies of high voltage stage are discussed in detail. The practicability of the method is verified by MATLAB/simulation results. Finally the high voltage stage experiment system is established by H bridges made of IRFP460, and comprehensive control of the stage is realized by fixed-point 32-bits DSP controller TMS320F2812. The experiment results show that the system can achieve voltage equalizing of every H bridge, operate under a unit power factor condition on the grid side and realize reactive real-time power compensation, possessed of a good performance of dynamic and static response.