Digital Control System Based Isolated Totem Pole Converter for Electric Vehicle Onboard Chargers

The Totem-Pole converter is well-suited for lowpowered electric vehicle (EV) applications. The isolated configurations of such converters provide single-stage power conversion that overcomes the more conversion stages. A robust controller can satisfy the converter operations efficiently for on-board charging applications. In this paper, a modified digital control method for totem-pole PFC cascaded active flyback DC-DC converters functioning in discontinuous conduction mode (DCM) is proposed. The auxiliary switch and clamp capacitor are used to recycle the stored energy in the transformer to reduce the spike voltage. The main purpose of adding PFC is to obtain the input current in phase with the input voltage, keeping total harmonic distortion (THD) low to improve the efficiency of the converter.