This paper presents a high step-up fully soft switching interleaved Sheppard-Taylor converter to be used in PV applications. The proposed converter utilizes only one auxiliary switch to create the soft switching conditions for all semiconductor devices. The converter has a simple structure, and its control circuit remains PWM. Moreover, the auxiliary switch is not located in the main power path; therefore, the conduction losses are decreased, and the overall efficiency is improved. Besides, the rate of the auxiliary switch current will be very low. On the other hand, the proposed converter has a high-voltage gain. Furthermore, all switches and other circuit elements have low current stress due to the interleaved structure in the proposed converter. The guidelines for the design consideration are presented. A 250 W, 25–250 V laboratory prototype operating at 100 kHz is implemented to verify the performance of the converter and an efficiency of 96% at full load can be achieved.
