An Improved Current Feedforward Control Strategy for Multi-port Power Electronic Transformer

Due to the high energy density and transfer efficiency of Multi-port power electronic transformer (MP-PET), it has attracted extensive application in the hybrid distribution systems. However, the coupling relationship between different ports which could impact the dc bus voltage fluctuation and port stability of the PET during load changes. Thus, this paper establishes a full-order small signal model of MP-PET to analyze the coupling mechanism between different ports. Moreover, according to the interaction mechanism, an improved current feedforward control strategy is proposed which can be used to reduce coupling in the stable region. Adopting this proposed method, the dc bus has a smaller voltage fluctuation compared to the traditional control strategies. Simulation and experimental results show the effectiveness of the proposed control strategy.