A soft switched step-up DC–DC converter using a low-power auxiliary circuit and continuous input current

In this paper, a new high step-up DC–DC converter is presented. The presence of an inductor at converter input reduces input current ripple. Furthermore, a coupled inductor with a voltage multiplier cell is also implemented to increase the voltage gain of the converter. The stored energy in leakage inductance of coupled inductor is recycled by a clamp circuit which increases efficiency and clamps voltage on power switch. The power switch is turned on and off under soft switching condition. The soft switching is also applied to auxiliary switch. All diodes are turned off under zero current condition which causes reverse recovery problem to be alleviated. A very low current flows through auxiliary components in a very short time. Therefore, a very low conduction loss is added to the converter by an auxiliary circuit. Soft switching condition is almost independent of specifications of circuit, especially the output power. Steady-state analysis of the proposed converter is discussed. Finally, to verify the performance and validation of the proposed converter, laboratory results for a prototype with input voltage 30 V, output voltage 240 V, output power 220 W and switching frequency 50 kHz are presented and the results are discussed. The efficiency of the prototype converter at nominal power is 96%.