Novel technique for power factor correction in flyback converters

Due to the necessity of DC power supplies that combine variable step-up and step-down DC output voltage, high power density and low harmonic distortion at the mains side, power factor correction in flyback converters has become a great issue. The paper presents a novel method to achieve high power factor correction in flyback converters without sensing the input current. This method is extended to give to a simplified and accurate design strategy for this type of converter, revealing an optimal solution under any operating point.