30-08-2017, 11:47 AM
The rectifier is composed of a single-switch diode bridge pulse rectifier in parallel with a three-phase pulse-modulation (PWM) unidirectional pulse rectifier. The aim 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. Therefore, the PWM unidirectional rectifier is designed to operate with a small power and with a high switching frequency. The total harmonic distortion of the proposed structure varies from 0% to 32%, depending only on the amount of power processed by the three-phase PWM unidirectional rectifier. The design of the rectifier topology, operating principle, control scheme and simulation and experimental results of a 20 kW laboratory prototype are also presented in this document.