Double Switches Quadratic High Step-up Converter Based on Coupled Inductance

In order to solve the problems of low voltage gain and high voltage stress of switches in traditional converters, a high gain converter based on switched capacitor and coupled inductor is proposed by cascading the quadratic structure with the boost module of coupled inductor. The converter uses the switched capacitor as a passive clamp circuit to absorb the leakage energy and effectively suppress the voltage spike caused by the resonance between the parasitic capacitor and leakage. The steady-state characteristics of the converter in CCM mode are analyzed when the coupled inductor turns ratio is 1 and duty cycle is 0.5, and the voltage gain is 14. The two switches are triggered in the same phase, which effectively reduces the average current stress of switches and improves the reliability of the converter. At the same time, the voltage stress of the switch can reach 1/7 of the output voltage, and with the increase of the turn ratio, the voltage stress is lower. The design scheme of the coupled inductor turns ratio and inductor quantity is given, and a 140w prototype is built. The experimental results prove the correctness of the theoretical analysis, and the efficiency of the prototype is more than 93% under the rated power.