Design and Control of Two Stage Battery Charger for Low Voltage Electric Vehicle using High Gain Buck-Boost PFC AC-DC Converter

A two-stage battery charger for the low voltage electric vehicle (LVEVs) is presented in this study. The presented charger utilizes a bridgeless version of an AC-DC converter having features of high gain and high-power factor along with continuous input current and comprehensive operational range capability at its front end. Whereas, at its back end, an isolated Cuk DC-DC converter is employed to control and implement different modes of battery charging, viz. constant current (CC) and constant voltage (CV) charging profiles. The presented AC-DC converter inherently achieves improved power quality at AC mains while operating under discontinuous current mode (DCM) operation and, therefore, incorporates minimum control complexity at the AC-DC stage of the charger. Thus, the DCM design and high voltage conversion ratio allow it to function reliably over a comprehensive range of input and intermediate DC link voltage, enabling the presented charger to deliver a wide battery voltage range at its output. In this work, the overall operational analysis and performance validation of the presented two-stage charger are carried out.