Fuzzy maximum power extraction control for a photovoltaic water pumping system
AC loads present a delicate matter for photovoltaic systems, and this is because of the photovoltaic panel's operating point, which moves randomly according to irradiance changes; in this case, almost of photovoltaic water pumping systems use a DC–DC converter to ensure either the maximum power extracted from PV panel or the load needs. For AC motor pumps, an inverter must follow this chopper. Adding more components to the pumping system leads to reduce its yield. That is why we suggest a new photovoltaic water pumping strategy in which the DC–DC converter is discarded. The idea is to provide cheaper and more efficient, relatively small, water pumping station, dedicated for remote areas. The control strategy imposes the operating regime for the scalar controlled single–phase induction motor pump by imposing the operating frequency, e.g., its absorbed power near the MPP operating point of the PV panel and this according to fuzzy logic algorithm. For this, a modelling of all system components is detailed. Simulation results show the effectiveness of the proposed control strategy.
Keywords: fuzzy control, PV water pumping, load matching, amorphous technology, single–phase inverter, PWM, pulse width modulation, single–phase induction motors, SPIM, centrifugal pumps, stand–alone systems, photovoltaic water pumping, remote areas, fuzzy logic, modelling, simulation