An improved three phase diode rectifier with input power factor correction

A new approach to improve power factor and reduce harmonics generated by a three phase diode rectifier is proposed. The proposed approach is passive and consists of a novel interconnection of a star/delta transformer between the AC and DC sides of the diode rectifier topology. This novel interconnection is shown to generate a circulating third harmonic current between the AC and DC side of the rectifier bridge. The circulating third harmonic current is then shown to drastically improve the performance of the diode rectifier type interface. The resulting point current is near sinusoidal in shape with significant reduction in line current harmonics. Experimental results from a 6 kW laboratory prototype are detailed