A Novel High-Step-Up Coupled-Inductor DC-DC Converter with Reduced Power Device Voltage Stress

In this paper, a novel high-step-up coupled-inductor dc-dc converter is presented. The proposed converter has an excellent feature, i.e., the closer the turn ratio to 1, the higher the gain of the converter, also the lower the voltage stress of the switch. Duty cycle and the turn ratio of the coupled inductor together determine the voltage gain of the converter; thus, it can achieve any wanted voltage without the circuit to operate at the extreme duty cycle. In addition, the proposed converter can realize higher voltage gain with a small duty cycle. And it is suitable for many types of new energy source, especially photovoltaic generation systems, which has a common ground and a continuous input current switch with great benefits for the life of the input power supply. The power density of the system improves for the lack of isolation transformer. Due to the introduction of the clamp circuit, the voltage spikes across the switch are limited. Therefore, we can choose a switch with lower voltage levels that would cut costs and reduce conduction losses. As the energy of leakage energy is absorbed by the circuit, the efficiency is further improved. The operational principle and the steady-state analysis of the proposed converter are presented in this paper. Finally, the experiment with an input 48-V voltage and an output voltage of 380 V is implemented, verifying the validity of this paper.