Design and development of DC-DC single-ended primary inductor converter (SEPIC) for maximum photovoltaic power extraction

Abstract

Recently, photovoltaic power generation has been one of the most dependable renewable energy sources which are used in electrical generation system. The performance of the photovoltaic system is the most significant for the maximum power point tracking (MPPT) and is absolutely relied upon the irradiance and temperature of the solar energy. To obtain a maximum power from a photovoltaic system, a high efficiency of DC-DC converter is desired and strongly dependent based on the input of the PV module. A DC-DC SEPIC converter is proposed as the controller to track the maximum power point (MPP) by simulation and hardware experiment. Unlike buck-boost converter, SEPIC converter is a non-inverted output as it uses a series capacitor to separate the input from the output and provides the choices to have either higher or lower output voltage compared to the input voltage. The buck-boost converter has a discontinuous input current characteristic that roots to a more power losses due to input switching. Besides that, SEPIC converter has -9 contended input current and better efficiency compared to buck-boost converter. Both simulation and hardware experiment results are proved based on the connections between PV module, SEPIC converter and load by varying the irradiance and duty cycle but at constant 25˚C temperature. The curves characteristic of I-V and P-V for both simulation and hardware experiment shows a difference in terms of duty cycle arrangement from 0.1 to 0.9 and similarities for the MPP for all irradiance. The MPP for all irradiance achieved by varies the duty cycle of the SEPIC converter. As the irradiance increases from 100W/m2 to 1000W/m2, the point of the maximum power increases constantly. The analysis shows that SEPIC converter is essential to be used by PV planner to track a maximum power point for any solar irradiance.