Current Control Front End AC-DC Converter for on-board EV Charger Utilising Second Harmonic Compensation

AC-DC conversion mandatorily leave the second-order harmonic footprints in the currents on the DC bus which has large amount of ripple voltages calling for implementation of large DC-capacitance, which not only results in poor device power density but also alter the characteristics of the converter to a voltage source not suitable for eV charging applications which demands for current converters. The current harmonic pollution poses a huge threat while charging of batteries in terms of stability, safety, and efficient operation even executing as front-end stage for the cascaded buck type converter. This paper presents a new technique to extract the second order harmonics component from the current at the rectifier’s output using low computation and easily implementable different bandwidth moving average low pass filters. The second harmonic current compensator (SHCC) using single phase self-supporting voltage source inverter eliminates the second harmonic currents (SHC) in the output side without influencing the PFC configuration on the AC side, thus drastically reducing the size of the capacitance of the filter. The analysis of filtering technique and configuration of the compensator along with control of PFC is dealt in detail. The simulation results demonstrate the ability of the proposed compensator works well with PFC AC-DC converter to offer current based control suitable for battery charging without large 2 nd harmonic ripples. The simulation and analysis is performed by keeping the devices and parameters in their ideal nature.