A Single Stage SEPIC Converter for Electric Vehicles Charging System

Abstract

 In recent years, the combustion engine vehicles are replaced with Electric Vehicles (EV) as the pollution is less. Though the EV has been commercialized, charging facilities is the biggest hurdle for consumers to use EV. Lack of charging station is the major problem for consumers to utilize EV in their day-to-day life. Thus, the research has been increased in charger for EV. In this regard, the charging scheme with constant current (CC) and constant voltage (CV) is introduced in [1] where the battery life is been affected due to the presence of ripple in charging current. This ripple is reduced with the help of Dual Active Bridge (DAB) topology, which has inbuilt zero current and voltage switching where the power is transferred from primary to secondary bridge with the help of leakage inductor [2]. At present, single port charging station is mostly available in practice where only one EV can be charged at a time. This increases the waiting time for customers to charge their vehicle. A on-board charger (OBC) is introduced to reduce the congestion of EV at the charging station. The size of OBC is minimized by introducing the voltage source converter at the front end in the place of rectifier cum boost converter. The back end has multiple options of DC/DC converter in which DAB is preferred for the OBC [3]. The control technique for the OBC with DAB topology is focused in [4] for obtaining the smoother operation and various DC/DC converter is discussed for the reduction of converter size. The waiting time of the consumer can be reduced by proper scheduling and forecasting process as discussed in [5].

A high gain DC-DC converter with the combination of boost and CUK converter is designed which provides better efficiency [6]. Though the efficiency is high, it requires two converters to charge the EV. In [7], only SEPIC converter is used for designing the OBC. In this topology, the frond end consists of rectifier with AC supply which provides DC output to the SEPIC converter at the back end. In the proposed topology, the AC input with rectifier is replaced with PV panel which provides direct DC supply. This reduces the number of power electronic components which in turn minimizes the power loss. Two SEPIC configuration is used in isolated condition. The isolated SEPIC configuration gives the multi-step current output which provides the different charging condition such as fast and slow charging.