A novel low-harmonic three-phase rectifier

A novel three-phase low-harmonic rectifier is proposed. The rectifier consists of a diode bridge, three bi-directional switches that are switched at the double of the line frequency, and a current shaping network. Two current shaping networks are proposed, the first one consisting of two capacitors and three resistors or switching resistance emulators, and the second one consisting of two capacitors, two resistors and a transformer. The power processed by the resistors or resistance emulators is shown to be equal 8.81% of the input power. The rectifier is suitable for application at medium and high power levels, since only the small amount of the input power is processed by high-frequency switching converters, and as a retrofit upgrade of existing rectifiers, requiring connection at only five points. Design guidelines are presented. Switching resistance emulation is discussed, and its feasibility is demonstrated. Analytical results are experimentally verified on a 2 kW rectifier.