Hybrid cascaded high step-up DC/DC converter with continuous input current for renewable energy applications

This study proposes a new structure of hybrid cascade coupled-inductor high step-up (HCCIHSU) DC/DC converter for renewable energy sources. The proposed topology can provide an ultra-high voltage gain under continuous input current and low voltage stress on semiconductor devices. This converter is a hybrid cascade connection of the boost and buck-boost converters. The HCCIHSU utilises a coupled-inductor (CI) and a voltage multiplier (VM) cell to enhance the voltage gain ratio as a semi-quadratic function. The magnetic energy of the leakage inductor of the CI is recycled to the VM capacitors that reduce the component voltage stress and improve the converter voltage gain. Additionally, the voltage stress on the main power switch is clamped by two passive clamp capacitors. Due to the very high voltage conversion ratio at a reduced turn's ratio, the maximum voltage stresses on the switches and diodes are significantly alleviated, which further improve the efficiency. In this study, detailed steady-state analysis and comparisons with other related converters are provided. Finally, a 160 W/200 V laboratory prototype is built with 24 V input voltage at a switching frequency of 50 kHz to verify the performance of the proposed converter.