A single reset integrator based implementation of line current shaping controller for high power factor operation of flyback rectifier

The objective of this paper is to present a simple yet accurate implementation of a resistor emulator type line current shaping controller for high power factor operation of a flyback rectifier. The important feature is input voltage sensing is not required. In circuit realization of the controller no multiplier is used. Current shaping is performed directly on the input filter inductor current. The modulator uses only one reset integrator for the generation of duty ratio. The analysis presented in this paper shows the effect of input filter capacitance on discontinuous conduction mode (DCM) of operation of the flyback inductor. Design equations for selection of the input filter components are derived. A low frequency small signal model of the rectifier is developed and verified by measurement up to 1 kHz. The performance of the controller is first tested by SABER circuit simulator package. Then a 100 W, 110 V AC input, 50 V DC output, single phase flyback rectifier prototype is built for experimental verification.