High Step-Up Three-Port Converter for Renewable Energy Systems

In this paper, a high voltage gain non-isolated three-port converter with a three-winding coupled inductor is proposed for renewable energy system. By implementing a cascoded structure where a photovoltaic (PV) source is stacked on top of a battery voltage source, the high output voltage can be achieved with a reasonable duty cycle, resulting in higher efficiency when both sources provide energy to the load. Furthermore, only three power switches are needed to regulate the energy flows among the three ports. When the low-voltage PV source provides energy to the load, the primary winding and the secondary winding of this coupled inductor are connected in series with opposite polarities to increase the voltage gain of the proposed converter.The use of a clamp circuit allows for the recycling of leakage inductance energy, which helps to reduce voltage spikes on the power switches. This results in the selection of low on-resistance switches and leads to higher converter efficiency. The proposed topology's operations, steady-state analyses, and key parameter designs are then discussed. To validate the performance of the proposed converter, a 300 W laboratory prototype is implemented.