Abstract: To cope with the increasing demands of the application of high step-up DC-DC conversion，such as

the absorption of renewable energy，electric vehicles and aerospace，a high step-up DC-DC converter based on

three-winding coupled inductor with low voltage stress was proposed by utilizing magnetic coupling technology to

design three-winding coupled inductor and mixing with switched capacitor structure. The converter has the merits

of high voltage gain，low voltage stress of devices and soft switching of all diodes. Each operational mode was

analyzed，the voltage conversion gain was deduced，the voltage and average current stresses of all devices were

obtained. Finally，a prototype in the condition of 120 W was produced to achieve voltage conversion of 386/23.8 V

DC-DC and verify the theoretical analysis and the feasibility of the proposed converter.

      Key words: high step-up converter；DC-DC converter；three-winding coupled inductor；low voltage stress