A Single-Switch HPF AC-to-DC Converter with Low Voltage Ripple

This paper proposed a single-stage single-switch ac-to-dc converter which is derived by integrating a boost converter and a flyback converter. Only one active switch and simple control are required. The boost converter performs as a power-factor corrector (PFC) which is designed to operate at discontinue-conduction mode (DCM) to makes the input current be a sinusoidal waveform and in phase with the input voltage. High power factor and low total current harmonic distortion (THD) are ensured. The flyback converter further regulates the output voltage of the boost converter to provide an isolated dc voltage with low voltage ripple. The flyback converter is designed to operate at continue-conduction mode (CCM) to have the transformer current of a low peak value. It will be effectively reduce the switching stress and the switching losses of semiconductor components. The paper conducts the mathematical equations for the converter circuits, and then designing the circuit parameters. A prototype circuit designed for a 100 W output power was built and tested. Satisfactory results are obtained experimentally.