Input stage improved power factor of three phase diode rectifier using hybrid unidirectional rectifier

This work describes a method in improving the input current power factor as well as the voltage regulation of a three phase diode rectifier circuit. In this method, a single-switch diode bridge boost-type rectifier in parallel with a pulse width modulation (PWM) three-phase unidirectional boost rectifier are used across the three-phase supply and load. The objective is to obtain a structure capable of providing sinusoidal input currents with low harmonic distortion and dc output voltage regulation. The diode rectifier operates at low frequency and has a higher output power rating. Therefore, the PWM unidirectional rectifier is designed to operate with a small power rating and at a high switching frequency. The rectifier topology conception, principle of operation, control scheme, and simulation are also presented in this paper.