High Power Factor AC-DC Converter Without PFC Preregulator

AC-DC converters are widely used in many industrial applications for electrical power conversion such as for telecom equipment, electric vehicles, information technology equipment, power systems and space power systems power systems based on renewable energy resources. Conventional AC-DC converters generally have two conversion stages, an AC-DC stage that operates with some sort of power factor correction to ensure good power quality at the input, and a DC-DC conversion stage takes the output of the AC-DC converter which is DC and converts it to the desired output DC voltage. Due to the cost of having two separate and independent converters, This paper proposes a single power-conversion ac–dc converter with high power factor. The proposed converter is dsigned by integrating a full-bridge diode rectifier and dc–dc converter. The proposed converter provides single power-conversion by using the novel control algorithm for both power factor correction and output control. Also, the active-clamp circuit clamps the surge voltage of switches and recycles the energy which is stored in the leakage inductance of the transformer. This converter provides maximum power factor 0.93.The operation principle of the converter is analyzed and verified. Experimental results for a 15 W ac–dc converter are obtained to show the performance of the proposed converter.