DC –DC Converters Types for Application in Electric Vehicles

Abstract

The attention towards Electrical Vehicles (EV’s) in present scenarios is increasing as they can possibly from a key workable transportation system in upcoming future with less CO₂ emission, reduced dependency on fossil fuel and high efficacy. Bi-directional converter enables energy transfer from vehicle to grid (V2G) and vehicle to home (V2H) along with charging from grid to vehicle (G2V). Inter-connection of the vehicle battery to the AC-DC link in both the modes of charging as well as discharging respectively is simplified by implementation of Non-Isolated Bi-directional DC-DC Converter. Assemblage of DC-DC converter is done by assimilating buck and boost converters, this enables it to work in both the directions charging as well as discharging in both the modes buck as well as boost. In the whole operating range soft- switching is independent of the state-of-charge of electric vehicle, while also ensuring stability of the grid voltage port regardless of load or generation conditions, has been also unified to decrease the losses in transition modes. In endeavour to reduce the size and converters weight, frequency of switching must be enhanced, this is realized by PWM controlled dc-dc bidirectional converter. The PWM switching of duty cycles is analogous to an electrical transformer between input and output voltages, where the amplitudes of positive and negative half cycle of input voltage are same as that of output voltage. This paper deals with in brief discussion about the different converter topologies most appropriate for achieving vehicle-to- grid (V2G) conversion in EV’s, also to decrease loss of power and attain greater conversion efficiency.