Global MPPT method for partially shaded photovoltaic modules

Among Renewable Energy Sources, the solar energy represents an attractive alternative solution to traditional sources because is available everywhere; moreover, photovoltaic (PV) modules are nowadays becoming more and more attractive as the price per watt of the photovoltaic modules is decreasing. The output voltage furnished by a PV module is quite low; therefore, a series connection of different modules has to be employed in order to obtain a sufficient output dc voltage. In non-uniform irradiation conditions of a PV array, traditional Maximum Power Point Tracking (MPPT) algorithms can converge to a relative maximum point, thus output power becomes lower than the absolute maximum. Since the conversion efficiency of commercial photovoltaic modules is still rather low, to increase the power produced, also under partially shaded conditions, is necessary to employ an efficiently, fast and simple MPPT. The paper proposes, for a Switched Capacitor-Boost converter structure, a non-conventional MPPT method able to track the absolute Maximum Power Point (MPP).