High step-up interleaved zero-voltage transition dc-dc converter with coupled inductors

Abstract

A high step-up DC-DC converter which is applied to a voltage lift capacitor and coupled inductors to increase the voltage gain is proposed in this study. Moreover, the interleaved structure is applied in the converter to decrease the input ripple current. Besides, the voltage stress across the main and auxiliary switches is low. Furthermore, all switches and diodes have the soft-switching condition by using an active clamp auxiliary cell. Consequently, the proposed converter has a high efficiency which is ideal for photovoltaic applications. Energy stored in the coupled inductors is transferred to the voltage lift capacitors and then transmitted to the output. Therefore, no voltage spikes caused by leakage inductors are created on the main switches. The converter operates in continuous current mode and its control remains in pulse width modulation. A 210 W laboratory prototype of the converter with 40 V input voltage and 420 V output voltage under 100 kHz switching frequency is constructed and experimental results confirm the theoretical analysis. Low voltage stress, low input ripple current and high efficiency (96.5%) show the superiority in the operation of the proposed converter in comparison with other similar structures.