Coupled inductor based ZVS high step-up DC/DC converter in photovoltaic applications

In photovoltaic applications, a high step-up dc/dc converter is required to serve as the power electronic interface between the low voltage solar panel and the high voltage dc bus. In this paper, a novel high step-up dc/dc converter is proposed to enhance the performance of voltage converting. The proposed converter is based on a coupled inductor, and integrates synchronized boost topology and switch capacitor based flyback topology. This circuit demonstrates advantages including a) high voltage gain without extreme duty cycle, b) zero-voltage-switching (ZVS) and low voltage stresses on both MOSFETs, and c) switch diodes turned off at low di/dt. These features ensure its feasibility and high efficiency in high step-up applications. The operating principles and theoretical analysis have been presented, and verified by experiment. A 24 V to 380 V, 100 W, 90.95 % efficient prototype is designed to verity the proposed scheme.