Electrolytic capacitor-less single-power-conversion on-board charger with high efficiency

Abstract

This paper presents an electrolytic capacitorless single-power-conversion on-board charger with high efficiency. The proposed on-board charger is composed of a step-up ac-dc converter which includes an active-clamp circuit and a series-resonant circuit. The active-clamp circuit provides a zero-voltage switching of switches and recycles the energy stored in the leakage inductance of the transformer. Also, this circuit clamps the surge voltage of switches. The series-resonant circuit reduces reverse-recovery problem of output diodes by providing a zero-current switching. Especially, the control algorithm is developed to achieve high power factor under the universal input voltage without the help of the any auxiliary circuit. Thus, due to these characteristics, the proposed charger can achieve high power efficiency and high power factor. In addition, the structure of single-power-conversion is very beneficial to the on-board charger that is installed in the vehicle. To confirm the theoretical analysis and validity of the proposed on-board charger, a 2-kW prototype is implemented under the universal input voltage.