A charge equalizer with a combination of APWM and PFM control based on modified half-bridge converter

A charge equalizer with a combination of asymmetrical pulse-width-modulation (APWM) and pulse-frequency-modulation (PFM) control based on modified half-bridge converter for electric vehicles (EVs) is proposed in this paper. The reliability of the charge equalizer can be enhanced because the split capacitors are not required and the soft-switching of power switches can be achieved by the proposed control. In addition, the number of the bridge-rectifiers at the secondary-side of the transformers can be reduced by half, which also cut the cost and conduction loss by half with the proposed rectification. The circuit topology and operation analysis of the proposed charge equalizer are described. Finally, the simulation is provided to verify the performance of the proposed equalizer.