Coupled-inductor boost converter with simple resonant technique

A coupled-inductor boost converter (CIBC) is a popular solution for high step-up applications. In order to relieve the drawbacks caused by a coupled-inductor (CI) and to further improve the efficiency, the simple PWM resonant technique for the CIBC is presented. The proposed circuit utilizes the leakage inductance of a CI and a switch voltage clamping capacitor as a resonant tank, which requires only a small modification in a conventional circuit. The sinusoidal current waveform shaped by the resonant tank reduces the switch turn-off loss considerably as well as the reverse recovery on the diode. This results in higher efficiency without additional circuitry. A 24 V input and 220 V, 110W output prototype is built to verify the proposed circuit.