Active clamp boost converter with switched capacitor and coupled inductor

A high step-up converter with a coupled inductor and a switched capacitor is proposed in this paper. By using the coupled inductor, the voltage gain of the converter is extended and the voltage stress of the main switch is decreased to reduce the conduction losses. Moreover, the reverse-recovery problem of the output diode is alleviated by the leakage inductance. By using the switched capacitor, the resonance between the leakage inductance and the stray capacitor of the output diode is eliminated. Additionally, an active clamp circuit is induced here to depress the voltage spikes of the main switch and to recycle the energy stored in the leakage inductance. Both the main switch and the clamp switch work with zero-voltage-switching (ZVS) performance, which reduces the switching losses significantly. At last, a 500 W prototype is built to verify the analysis. The highest efficiency of the prototype is 96% and the efficiency is over 93% in a wide load range.