Improved Power Quality Charging System Based on High Step Down Gain Bridgeless SEPIC APFC for Light Electric Vehicles

A bridgeless charger configuration based on switched inductor SEPIC (Single Ended Primary Inductance Converter) converter (SISEPIC), is presented in this work. A single-stage charging solution with high step-down DC voltage gain with limited supply current distortions and unity true power factor (TPF) operation, is established for light electric vehicles (LEVs). The magnetic components of the charger are designed for discontinuous conduction mode (DCM) to minimize the cost and size of the charger. Furthermore, a wide fluctuation in the supply voltage is considered during the design to ensure the safe and reliable operation. Moreover, different battery charging stages such as constant current state (CCS) and constant voltage state (CVS) is accomplished with reduced sensors and minimum control complexities. In addition, the bridgeless configuration of the charger reduces conduction losses, especially at the low supply voltage. This charger is designed, and its performance is analyzed through simulation and validated by a prototype in the laboratory. The behavior of the charger during steady-state as well as during dynamics is recorded, and test results are demonstrated in detail. The charger provides low supply current distortions and unity TPF at the grid with minimum cost, size, number of sensors, and control complexities.