FPGA Based Digital Controller for Two Stage On-Board EV Charger

This paper presents a Field Programmable Gate Array (FPGA) based digital control system of two stage (AC-DC; DC-DC) on-board Electric Vehicle charger for achieving boost power factor correction, constant current-constant voltage (CC-CV) and zero voltage switching (ZVS) operations with single stage voltage and current controller. Conventional on-board chargers, which are used for EV battery charging has serious issue of drawing peaky input AC current and extreme current ripples in battery charging current profile. Therefore, the conventional EV chargers have adverse effects on utility grid, low power factor, EMI effect and life hazard for the EV batteries. An on-board EV charger must have following characteristics such as unity power factor operation, galvanic isolation, CC-CV Charging Operation, fast charging, dynamic stability and low switching losses. In order to include these key features in an on-board battery charger, a two-stage charger design and various control operation using FPGA-based digital board are discussed in this paper.