An Improved Power Factor Luo Converter based Battery Charger for Electric Vehicle

This work focuses on a new high step-up gain Luo converter with reduced device stresses, for power factor correction (PFC) at front-end of electric vehicle (EV) battery charger. To produce the same DC-link voltage, the benefit with this converter, is achieved in terms of low device stresses as compared to a conventional Luo converter. This new Luo converter operates at lower duty cycle due to switched inductor structure at input, which facilitates reduced conduction loss and better charger efficiency. A flyback converter is used at next stage, which controls the battery current during constant current-constant voltage mode. The high gain converter as well as a flyback converter design is achieved in discontinuous conduction mode (DCM). This gives the advantage of reduced cost and size with less sensors in the circuit and low magnetic volume. A prototype is developed to test the improved power quality (PQ) performance of the charger, at steady state and at sudden varying line voltages. A comparative study of this converter with other voltage-lift type Luo converter in the literature, is given to show the reduced device stress, less components and improved efficiency.