An Weak Bus Based Bridgeless Charger for Three Wheeler EVs

Three wheeler Auto-rickshaw/ Light Electric Vehicles have a 48V/60V lead acid battery, which is charged from a 220V RMS AC single phase supply. A converter system introduced in this paper has a weak bus voltage, varying with the input line cycle with a constant conversion gain. This type of bus voltage enables the use of a very low valued capacitor at the link. This reduces cost, space and improves reliability of the overall system. The front end is realized with a bridgeless power factor correction circuit with high efficiency at this power range of 800W. Back end battery facing converter creates a pulsating current waveform, varying at twice line cycle, delivering the required average current to the battery. Buck converter operates using a hysteretic current control mechanism, reducing flux swing in inductor core. The converter system is designed for a 12A average charging current through the battery. The design is extensively simulated using PLECS simulation platform. High power factor and reasonable THD is achieved across the whole converter operating range.