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. 500 W prototype converter is built and its experimental results are given to verify the effectiveness of the proposed PWM strategy.