Modeling and Simulation of Multipumping Photovoltaic Irrigation Systems

The growing market of large-power photovoltaic irrigation systems (PVISs)-made of systems with different and several motor pumps working in parallel-needs simulation tools capable to estimate their energy and water productivity. The objective of this paper is to present the simulation models developed for parallel multipump PVISs fed by a single PV generator. These models seek to maximize the instantaneous water flow rate according to the available PV power and were developed for the typical configurations of large-power irrigation facilities. The models present some advantages when compared with the current state of the art (in which a single motor pump connected to a 1/N fraction of the PV generator is simulated and the result is multiplied by N): in the case of negligible hydraulic friction losses, the use of the multipump model shows gains with respect to the state of the art; in the case of appreciable friction losses, the current state of the art overestimates the productivity of the systems. Then, the ability of these models to compare different multipump designs is shown: two groups of pumps working at variable frequencies show better performance than a group working at a variable frequency and a group at a nominal frequency-an 8% increase in the water pumped is seen.