Local model predictive controller

This paper proposes a new predictive control strategy for a distributed collector field of a solar desalination plant. The main purpose of the controller is to manipulate the water flow rate to maintain constant the outlet-inlet temperature gradient in the collectors in spite of disturbances. The controller is based on a filtered Smith predictor generalized predictive control algorithm and a simple procedure to update the linear model used in the predictor in such a way that the nonlinear optimizations is avoided. The controller copes with the process nonlinearities, constraints, deadtime and plant-model mismatch obtaining the desirable performance both, in the reference tracking and rejecting strong irradiance disturbances. Real experimental tests of this technique in the AQUASOL desalination plant solar field are presented to show the advantages the proposed controller.