A novel soft switching minimum phase electric vehicle charger for wide range operating voltage/current

Abstract

This article proposes a soft switching minimum phase Electric Vehicle charger (SSMP-EVC) for a wide range voltage/current charging application. The proposed charger is designed to transfer power from utility grid to electric vehicle's (EV) batteries in two stages at domestic places. A novel ac-dc converter is designed at stage I to accommodate (i) ac-dc conversion (ii) power factor correction (PFC), and (iii) boost-buck operation. In stage II, a LLC resonant dc-dc converter is incorporated to provide (i) galvanic isolation, and (ii) soft switching operation. The available household EV chargers do not show versatile charging compatibility with different EVs due to their application specific design and dynamic non-linear characteristics. Therefore, a minimum phase EV charger is proposed and designed to achieve a universal charger for different EVs. Due to minimum phase characteristics (MPC), the proposed charger has following advantages such as easy to control, better dynamic performance at different operating conditions and high load current carrying capabilities. Further, a three loop cascaded controller is designed to achieve a wide range charging capabilities along with a novel pulse width modulation (PWM) scheme. The performance of the proposed charger is verified for wide range of output voltage/current rating in EV charging applications.