Robust constrained predictive feedback linearization controller in a solar desalination plant collector field

Abstract

This paper proposes a feedback linearization strategy for a solar collector field, which is a constrained non-linear processes. The benefits of input–output feedback linearization are improved by a filtered Smith predictor-based model predictive control algorithm with embedded variable constraint mapping to take advantage of: (i) linear control without losing the intrinsic non-linearities typical of thermal power plants; (ii) including input amplitude constraint handling capabilities due to control signal saturations induced, for example, by strong irradiance disturbances or plant start-up; and (iii) avoiding unstable or highly oscillatory responses caused by plant-model mismatch. Simulation studies are first presented to analyze robustness and constraint-mapping features, and real experimental tests of this technique in the AQUASOL desalination plant solar field have been included to demonstrate the advantages of its implementation, especially for reference tracking despite disturbances.