Isolated Power Factor Corrected High-Gain AC–DC Buck-Boost Converter-Based Single-Stage LEV Battery Charger

A single-stage on-board charger for light electric vehicle (LEV) batteries, based on an isolated high step-down gain bridgeless AC–DC buck-boost converter, is presented in this study. This charger offers several advantages over a conventional two-stage charger, which include reduction in overall component count, reduced cost and size, eliminationVehicles of electrolytic DC Link capacitor, reduction in control effort, and better dynamic voltage regulation. An overall efficiency of presented charger is enhanced by using bridgeless configuration of converter, which reduces conduction losses associated with a diode bridge rectifier. Additionally, converter is designed to operate in discontinuous conduction mode (DCM), which accords charger supplementary benefits of zero current switching to one diode and two switches of converter without a use of any auxiliary circuit. DCM operation leads to diminished size of magnetics and further, facilitates reduction of number of sensors required and control effort for implementation of various charging methodologies viz. constant current (CC) and constant voltage (CV). At supply end, charger operates at high power factor while exhibiting high voltage conversion ratio. This study authenticates feasibility of charger and its performance during both steady and dynamic states using simulations. Practical implementation and validation of theoretical features of charger are undertaken using a 450 W test bench setup, which attempts to emulate simulated results in real time environment.