A novel technique for variable-capacitor filter. I. AC current harmonic control

This paper introduces a novel technique for controlling current harmonics in power supply converter systems. A variable characteristics capacitive active filter is proposed and is used to control the AC current harmonics generated by a standard AC/DC converter with resistive load and a smoothing capacitor. The idea of the proposed filter is to use a combination of capacitors and switches to form a circuit which varies its capacitance with time. The filter will then generate harmonics in antiphase with the harmonics generated by the nonlinear load. Simulation and experimental results are presented.