Abstract: In order to overcome the shortcomings of the classic Boost converter，such as low boost ratio，large

input current ripple，and high voltage stress of power devices，a new type of zero input current ripple high gain nonisolated DC/DC converter was proposed. The combination of isolation type Sepic converter，coupled inductor type high-gain converter and passive ripple circuit unit can improve the voltage gain of the converter while also achieving the characteristics of zero input current ripple. The condition of the characteristic is not affected by the duty cycle. At the same time，the introduction of a clamping circuit effectively absorbed the energy stored in the leakage inductance，and weakened the voltage spikes generated by the drain and source of the switch tube when it was turned off. The working principle of the converter in continuous current mode was discussed，and the mathematical equations of steady-state characteristics such as voltage gain and voltage stress in this mode were given. Finally，a 500 W experimental prototype was made to verify the correctness of the theoretical analysis and feasibility of the proposed converter.

      Key words: voltage gain；input current ripple；passive ripple circuit；passive clamp circuit