A High Step-up Partial Power Regulated DC–DC Converter with Zero Input Current Ripple and Wide Input Range

A current-fed high step-up dc–dc converter with a post-stage partial power voltage regulator is proposed in this article. Two current-fed DCXs are included in the proposed converter and both operate at the unregulated state to achieve a constant conversion ratio. An auxiliary dc–dc converter is introduced for the system output voltage regulation under a wide input range through simple PWM control. Zero input current ripple of the system is realized by the complementary operation state of two DCXs over the entire operating range. The soft switching properties can be achieved for all the power devices in the system. Each converter in the system only processes a part of the total power, resulting in lower device stress and power losses. The operating principle, voltage regulation scheme, parameters design consideration and the small-signal modeling are introduced in detail. A comprehensive comparison is conducted with state-of-the-art converters considering input current ripple, input voltage range, soft switching characteristics, galvanic isolation and efficiency, which confirms the advantages of the proposed converter. Experimental results for a 400W laboratory prototype with 24–44V input and 400V output are provided to verify the performance and feasibility of the proposed converter.