A novel technique to achieve unity power factor and fact transient response in AC-to-DC converters

This paper presents a novel power factor correction technique for single-phase boost type AC-to-DC converters in continuous conduction mode. Instead of using the inductor current or switching device current, in this paper, the diode current in the boost converter is used to formulate the duty ratio of the switch in a special way which makes the input current sinusoidal and in phase with the input voltage. To improve the dynamic performance and minimize the input current harmonic components, a new double-injection compensation method is employed in the voltage feedback loop. The power factor corrector has the following advantages: (1) operation with constant switching frequency; (2) elimination of input voltage sensing, error amplifier in the current loop and multiplier in the output voltage feedback loop; (3) minimal total harmonic distortion in the input current; (4) fast dynamic response of the output voltage loop; and (5) simple implementation of the control circuit. The principles of operation of the proposed control scheme are explained. Simulation and experimental results are presented to verify the feasibility of the control strategy.