A Charge Equalizer With a Combination of APWM and PFM Control Based on a Modified Half-Bridge Converter

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