AC Side Switched Active Filter Based High Performance Three-Phase Buck Rectification

Input current and power factor improvements of single and three-phase rectifiers by switch mode regulators are usually achieved by switching the output of rectifier's diode bridge. In this paper a three phase buck rectifier is proposed which is switched at the input side by one three phase bi-directional switch. The input switching makes input current switched at high frequency, which is then filtered by a small filter along with a small low pass filter to get low THD input current at near unity power factor. This makes the control logic simpler for maintaining high input power factor and high input power factor. The proposed circuit is not valid for high power operation due to switching. Voltage and power limitation will depend on the ratings of the inductor, capacitor, diode, IGBT and other components to be used.