Operation and efficiency analysis of an MAB based three-phase three-stage power electronic transformer

Power electronic transformer will be a key component in the future power system. In this paper, an MAB based three-phase three-stage power electronic transformer is proposed. Its configuration is described and its control strategy is shown. Simulation result verifies the proposed PET and its control strategy. This paper then compares the MAB´s high frequency transformer(HFT) with the DAB´s HFT. It is concluded that when transferring a same power, an MAB HFT has higher efficiency than DAB HFTs. Therefore, the proposed MAB based PET has efficiency advantage over the conventional modular PET. This paper also shows a feed-forward method which adjusts the duty cycle of MAB H bridge converters to reduce the voltage ripple on the DC link capacitors.