New Topology of Quasi Resonant Flyback Converter

Flyback converter is well-known topology and utilized in many applications where galvanic isolation or a high ratio conversion rate is required. This paper presents a new topology of an isolated switch mode power-converter. The fixed-frequency quasi-resonant converter is based in flyback family operating in discontinues conduction mode. The converter uses zero-voltage-switching techniques to improve the converter efficiency. The converter comprises coupled inductor, two switches, and a diode on the primary side. At the secondary side, there is a diode, coupled inductor, and output capacitor. The new topology enables to run the converter at constant switching frequency while preforming a quasi-resonance behavior. In this paper, the innovative topology is presented. First, the circuit operation steps are described, then the analytical equations are developed. To validate the proposed theory a case study was made; the circuit was modeled by PSIM simulation tool. The results are acknowledged that the innovative topology can decrease the circuit losses dramatically throughout all operating points.