Performance improvement of a zero-voltage switching interleaved high step-up DC-DC converter with low-voltage stresses

This paper proposes a novel interleaved ultra-large gain zero-voltage switching (ZVS) DC-DC converter for renewable energy systems. By using coupled inductor (CI) and built-in transformer (BIT), a high-voltage gain is achieved. The secondary windings of the CIs are connected in series with the primary winding of the BIT and the secondary winding of the BIT is inserted in voltage multiplier cell (VMC). In such a case, the voltage gain is proportional to the multiplication of the turn's ratios of the CI and BIT. To increase the devices' utilization, the active clamp circuit not only provide ZVS performance for the metal-oxide-semiconductor field-effect transistor (MOSFETs) and recycles the leakage energy, but also participates in voltage gain enhancement. The voltage stress across the switches is considerably decreased and the low duty cycle reduces the conduction and switching losses. Low input current ripple, equal current sharing without a dedicated controller and common ground are the other merits of the proposed converter. Steady-state analyses are presented and through a fair comparison, the superiority of the proposed converter over the state-of-the-art is guaranteed. Finally, a 500-W laboratory prototype with 20- to 400-V voltage conversion is built to demonstrate the effectiveness of the proposed converter.