An efficient battery charging algorithm based on state-of-charge estimation for electric vehicle

This paper proposes the off-line battery charger for electric vehicle. In order to charge the battery for EV, the safety and charging time must be contemplated. Also battery charger requires that it is a capable of the high power capacity. Therefore, three-phase AC-DC boost converter is suitable for the off-line battery charger. It can transform from the three-phase utility input to DC output without additional rectifier circuit. The power factor correction can be implemented by the phase control by the Park's transformation. With the hardware system of the charger, the battery charging algorithm is important for the development of the charger. The battery charging algorithm is required to reduce the charging time and prevent the overcharging. In this paper use the Constant voltage-Constant current charging method is adapted for safely charging battery. However, it takes a long time for fully charging the battery, so this paper presents the improved CC-CV charging method. It helps reduce the total charging time. It is described by comparison of conventional CC-CV method and verified through the experimental results.