New methodology of speed-control of photovoltaic pumping system

The use of renewable energy is growing significantly in the world. In front of the growing demand for electric energy, essentially for the needs of remote, desolate, and mountainous regions, photovoltaic systems, especially water pumping systems, are beginning to emerge in large applications. In this sense, the proposed study deals with the problem of the water level regulation in the photovoltaic pumping system. To achieve this aim, a fuzzy logic controller has been developed in order to determine the reference speed needed for vectorial command of induction motor, taking into account the water level in the tank and the variation of solar irradiation. On the one hand, the energy management and control of the photovoltaic subsystem is based on voltage and current control with maximum power point tracking allowing the optimal transfer of power to the pump through two converters, a boost (DC-DC converter) and an inverter (DC-AC converter) are controlled by space vector pulse width modulation. On the other hand, the proposed study provides a comparison between a fuzzy logic controller and an algorithm controller. The latter technique is less successful than the first, but more easily implemented. The string of photovoltaic pumping is simulated under Matlab-Simulink. The results were promising, and yet they remain to be validated in practice. (C) 2013 AIP Publishing LLC.