Implementation of an interleaved single-stage high power factor converter

An interleaved single-stage AC-DC converter is presented to reduce line current harmonics, achieve power factor correction and eliminate reactive power. An integrated buck-zeta converter is adopted to reduce the voltage stress on medium DC bus. Thus power semiconductors with low voltage stress can be used in the converter. Since buck converter is operated in the discontinuous conduction mode (DCM), AC line current is automatically following the utility voltage and line current is a sinusoidal waveform and in phase with AC main voltage. The zeta converter is adopted to regulate the output voltage and achieve the transformer magnetic flux reset. Interleaved pulse-width modulation (PWM) is used to reduce the ripple currents at the input and output capacitors. The system analysis, operation principle and design consideration of the proposed converter are discussed in detail. Experimental results, taken from a laboratory 320 W prototype, are presented to demonstrate the converter performance. Based on the experimental results, the proposed converter reached a power factor of 0.98, a total harmonic distortion of 9% and an efficiency of 88%.