An improved high-power factor and low-cost three-phase rectifier

A new method to improve the power factor of three-phase rectifiers is introduced in this paper. The main features of the proposed circuit are low cost, small size, high efficiency, and simplicity. The power factor improvement is achieved with three bi-directional active switches rated at a small fraction of the total processed power, and gated at the line frequency. The principle of operation and design procedure, with a practical example, are also presented. The theoretical analysis was validated with experimental results from a laboratory prototype rated at 7.4 kW and connected to the 220-V 60-Hz AC system. The same circuit was also used in another prototype rated at 12 kW, with similar results.