Quadratic-type high step-up DC-DC converter with continuous input current integrating coupled inductor and voltage multiplier for renewable energy applications

This paper presents a quadratic-type high step-up DC-DC converter for renewable energy applications with a continuous input current. To reduce the number of components while increasing the gain, a quadratic boost converter and two multiplier cells are applied as the primary and secondary circuit with one coupled inductor connected. In addition, the clamp circuit shares its components with both the second boost stage and the voltage multiplier, which increases the power density. As a result, the leakage energy is recycled and the voltage stress can be suppressed. The operation principles and steady-state analyses including loss analysis of the proposed converter are addressed in detail. Compared with relevant existing topologies of quadratic converter, the proposed converter performs a higher voltage gain and a lower power switch stress. To validate the performance, a 200 W experimental prototype is constructed and tested with 20 V of input voltage and 400 V of output voltage, where the highest efficiency is 95.2% and the full-load efficiency is 93.7%. The performance under dynamic conditions is also verified. In the end, an improved topology based on the proposed converter is supplemented.