An advanced PWM strategy to improve efficiency and voltage transfer ratio of three-phase isolated boost dc/dc converter

This paper proposes a novel PWM strategy to improve efficiency and increase voltage transfer ratio of three-phase isolated boost dc/dc converter. With the proposed PWM strategy, one turn-off switching of each bridge switch is eliminated to reduce switching losses and RMS current of the bridge is lowered, so that the switches’ conduction losses are reduced. Transformer copper loss is minimized due to the reduced RMS current of the transformer’s each winding. Therefore, total losses are minimized and the efficiency of the converter is improved. In addition, the effective leakage inductance of the transformer is reduced by 25% compared with the conventional PWM strategy, which results in an increase of the output voltage at the same duty ratio. 500W prototype converter is built and its experimental results are given to verify the effectiveness of the proposed PWM strategy.