Three-phase high-power-factor rectifier with three ac power switches

Three-phase four-wire high power factor with less power switches are proposed to perform the power factor correction and dc-link voltage regulation. The adopted circuit configuration consists of six diodes with voltage stress v(dc), three ac power switches with voltage stress v(dc)/2, three boost inductors on the ac side and two capacitors on the dc side. Three balanced and sinusoidal currents are drawn from the ac mains such that the neutral line current is close to zero. Three voltage levels are generated on the phase to neutral of the rectifier. An output power estimator, proportional integral voltage controller and hysteresis current controller are adopted in the proposed control algorithm to perform line current command, compensate the switching losses of the rectifier and track the current commands. To balance the neutral point voltage, a neutral point voltage compensator is included in the proposed control scheme. Based on the proposed control strategy, the input power factor is close to unity and line currents are controlled to be balanced and sinusoidal. Experimental results were provided to verify the validity and effectiveness of the proposed control strategy.