High step-up DC/DC converter based on coupled inductor and switched capacitor unit

A high step-up DC/DC converter based on coupled inductor and switched capacitor unit was proposed. The switched capacitor units were integrated into the circuit topology and extended to n units. The degree of freedom for the converter to adjust the gain was improved, so that the voltage gain can be adjusted not only by changing the turns ratio of the coupled inductor, but also by increasing or decreasing the switched capacitor units. The current of leakage inductor in coupled inductor cannot be changed suddenly, so the reverse recovery of diode can be solved. The leakage inductor energy was well absorbed by the passive clamp circuit, which reduces the voltage stress of the switch and improves the efficiency and reliability of the converter. The operating principle of the proposed circuit topology was analyzed and the performance characteristics of the converter were compared. Finally, a prototype with input voltage of 20~40 V, output voltage of 380 V and rated power of 300 W was made for experimental verification. The main waveform is basically consistent with the theoretical analysis, and the measured maximum efficiency is 95.4%, which verifies correctness of the theoretical analysis and feasibility of the proposed converter. © 2021, Harbin University of Science and Technology Publication. All right reserved.