Power Factor Preregulation in Interleaved Luo Converter-Fed Electric Vehicle Battery Charger

This work deals with the design and implementation of a new interleaved Luo power factor preregulator (PFP)-based electric vehicle (EV) battery charger, which is suitable for low-cost and improved power quality (PQ)-based EV charging. By interleaving two Luo converter cells, the input current is divided between them, which provides reliable and efficient charging of the battery at high-power discontinuous conduction mode (DCM) operation. This reduces the switch conduction loss due to reduced device current stress and thus, the charger efficiency is improved. The interleaved Luo converter incorporates low input and output current ripple due to ripple cancellation. This charger operates in constant current mode up to certain battery state of charge (SOC). However, for higher SOC range, it maintains constant voltage charging using a flyback converter at the next stage. Two converters are designed in DCM to provide inbuilt zero current switching and circuit diodes show good reverse recovery. An inherent PF preregulation is obtained at input mains over a wide range of supply voltages as well as dc-link voltage. The total harmonic distortion of input current is obtained as per PQ regulations. Its prototype is built and tested to validate its improved performance over two-stage solutions.