An On-Board Fast Charger using New Bridgeless PFC Converter with Reduced DC-Link Capacitance

This paper proposes a new approach to design a fast charger for electric vehicle, which consists of a new bridgeless (BL) Zeta PFC (Power Factor Correction) converter with reduced size of DC-link capacitance cascaded by a buck converter. The battery fast charging is provided based on a new approach of operating the PFC converter at increased DC-link voltage, as compared to the conventional slow chargers. This implies to the reduced size of DC-link capacitance, as the value of DC-link capacitance varies inversely with respect to the DC-link voltage. The proposed BL Zeta converter has lower device voltage stress, which ensures a high-power density and better efficiency during fast charging at the battery end. A buck converter is used to control the battery current during constant current and constant voltage modes. Moreover, the operation of two converters in the discontinuous conduction mode (DCM) gives the benefit of fewer sensors as sensing of input side quantities is avoided. It is shown that with the proposed topology, the battery charging can be achieved 8 times faster than conventional BL Zeta converter.

Keywords: Fast Charger, Electric Vehicle, Power Factor Correction, DCM, Bridgeless Zeta Converter.