Energy Harvesting from the Photovoltaic Hybrid Power Source Based on Extremum Seeking Control Schemes

Abstract

The energy harvesting is known as the conversion process of ambient energy into usable electrical energy. The energy of the renewable and green Energy Sources (ES) is free and available without territorial restrictions. In this chapter the possibility to use the Extremum Seeking Control schemes for harvesting the solar energy via a Photovoltaic Hybrid Power Source is presented. The new ESC schemes based on a band-pass filter instead of the series combination of high-pass and low-pass filters are analyzed in order to evaluate their performance. The performance indicators used are the search speed and the tracking accuracy. The simulations performed highlight the advantages of the Extremum Seeking Control schemes based on a band-pass filter in comparison with the classical Extremum Seeking Control schemes. A Maximum Power Point tracking technique based on a modified Extremum Seeking Control slightly improves the energy efficiency of the Photovoltaic Hybrid Power Source. The advanced Extremum Seeking Control scheme reduces the power ripple, so the energy efficiency of the Photovoltaic Hybrid Power Source increases as well. The analysis of the dither persistence in the Extremum Seeking Control loop scheme shows the relations between the search speed and the derivatives of the Photovoltaic power. The ratio of these search speeds is also used as the performance indicator. Finally, the dynamical operation of the Photovoltaic Hybrid Power Source under variable irradiance profile is shown.