Novel Isolated High-Step-Up DC-DC Converter With Voltage Lift

A novel two-switch high-step-up isolated converter with voltage lift is proposed in this paper. The proposed isolated converter utilizes a transformer with low turn ratio to achieve high step-up gain. The secondary winding charges two boosting capacitors in parallel as switches during the switch-on period, and two boosting capacitors are discharged in series during switch-off period. Thus, the converter has high voltage gain with appropriate duty ratio. In addition, by using two clamping diodes and capacitor on the primary side, leakage energy is recycled and the voltage spikes of the two active switches are clamped, thereby improving conversion efficiency. Finally, experimental results based on a prototype implemented in the laboratory with input voltage 24 V, output voltage 200 V, and output power 200 W verify the performance of the proposed isolated converter; fullload efficiency is nearly 93%. Index Terms – High-step-up, two-switch isolated converter, voltage lift technique, high voltage gain