Design of a Three-phase Isolated SEPIC-Based Off-Board Fast Charger for Electric Vehicles

The industry of Electric Vehicles (EVs) is emerging as a significant solution for the environmental issues introduced by Internal-Combustion Engine (ICE) vehicles. This paper presents the design of a unidirectional three-phase fast charger for EV, using three single-phase modules of isolated SEPIC with Power Factor Correction (PFC) capability. The converter can be designed to operate in both Continuous or Discontinuous Conduction Modes (CCM or DCM). The presented concept is validated using MATLAB/Simulink platform, where the simulation results show an input current THD of less than 3% and an almost unity input power factor. Also, the effect of the source impedance on the input current THD is studied considering an insignificant SEPIC's input inductance.