High gain DC-DC converter for PV applications

In this paper a new single-switch non-isolated, DC-DC converter, with high voltage transfer gain and reduced semiconductor voltage stress is proposed. The high gain converter is designed by integrating a boost with quadratic boost converters. The high voltage gain capability at moderate duty-cycle and low switch voltage stress enable the use of a lower voltage and RDS-ON MOSFET switch to reduce cost, switch conduction and turn-on losses. In addition, the low voltage stress across the diodes allows the use of Schottky rectifiers for alleviating the unfavorable reverse-recovery current, leading to a further reduction in the switching and conduction losses. Hence, improved thermal management is obtained. The proposed topology utilizes single non-floating power switches, hence simple PWM control can be used to regulate the output voltage. Additional features include integrating both inductors on the same core, hence higher converter power density is attained. The principle of operation and comparisons with other high step-up topologies are presented. Simulation and experimental results are also presented to demonstrate the effectiveness of the proposed scheme.