Design and Implementation of Soft Switching Three-port High Step-Up DC-DC Converter for Solar Energy Applications

In recent few decades, due to various reasons, including energy crisis and environmental problems, renewable energy sources such as wind energy, solar systems and fuel cells have received much attention. Solar or photovoltaic systems are one of the most widely used renewable energy sources that have a low output voltage. For this reason, research on dc-dc converters has increased in recent years. In this paper, a non-isolated high voltage gain converter with three input-output ports is proposed. This converter provides two separate paths for power flow from each input source to the output load. In order to reduce the number of converter components, some components play multiple roles. Therefore, the energy storage device (battery) will charge with the same components used to transfer the power to the load. In this converter, to increase the voltage gain, the coupled inductor technique is used. Moreover, to reduce the leakage inductance as well as achieving the soft switching condition, two active clamps are used. Since the voltage across the switches is limited, the switches can be used with low voltage stress and thus low conduction losses. In this converter, the ripple of the input current will reduce by adding an inductor at its input. This has a significant impact on the performance and the lifespan of the solar cells. The various operational modes of the converter are discussed and the designing considerations are presented. A prototype of the proposed converter is simulated to supply a 130 W, 330 V load with a switching frequency of 50 kHz, in OrCAD software. Finally, a laboratory sample is implemented and the theoretical analysis are validated by the practical results.