Multipulse high power factor rectifier applying a novel current injection network

Abstract

A novel multipulse rectifier is presented. The proposed multipulse rectifier is based on previously reported three-phase low-harmonic rectifiers that apply the third harmonic current injection. The current injection networks require one inductor, two capacitors, and one 1:1 transformer with volt-ampere rating of only 0.16% of the input power. The transformer is introduced to provide control of harmonic components of the injected currents at even triples of the line frequency, resulting in significant reduction of the input current total harmonic distortion (THD). Dependence of the input current THD on the current injection network Q-factor is computed for both of the proposed current injection network versions. The THD is shown to be less than 5.125%. The multipulse rectifier is derived from previously reported rectifiers connected to two three-phase voltage sources having phase voltages shifted for 60 degrees. By such a method, the currents injected into the neutral point of the current injection device are cancelled, so there is no need for the current injection device. Analytically obtained results are experimentally verified.