Comparision of different techniques to improve the Input Power factor Of rectifiers

Abstract

At the input of AC-DC switching mode power supply, we often use a full wave rectifier and a parallel capacitor to get the direct voltage smooth and level. Because rectifier is non-linear and filter capacitor is an energy-stored component, the combination of those two will make the input alternating current distort greatly. Please see Fig.1. “t” for time (Seconds) ; “Vi” for electrical input voltage (Volts) and “ii” for electrical input current (Amperes). There are several harmonic waves present in the input pulse shape current. This will significantly lower the power factor. In addition, a high current harmonic emission will cause the circuit to get out of order and
distort the voltage contour. We must take action to restrict the input harmonic current in order to increase the input power factor and lessen the pollution generated by the AC-DC converter's input harmonic current. I want to compare and outline the various power factor correction techniques in this study. II. There are two popular approaches to raise the AC-DC converter's input power factor and lower its input harmonic current. Employing a standard "L" filter: To create a L filter, there are two methods: either attach a L filter at the rectifier's alternating side, or put an inductor between the rectifier and the filter capacitor C. Of course, you can combine these two ways together, and this will be more effective. Please see Fig.2. “t” for time (Seconds) ; “E” for electrical voltage (Volts) and “i2” for electrical current (Amperes).