Supervision and c-Means clustering of PID controllers for a solar power plant

A hierarchical control strategy consisting on a supervisory switching of PI D controllers, simplified using the c-Means clustering technique, is develo ped and applied to the distributed collector field of a solar power plant. The main characteristic of this solar plant is that the primary energy sour ce, the solar radiation, cannot be manipulated. It varies throughout the da y, causing changes in plant dynamics conducting to distinct several operati ng points. To guarantee good performances in all operating points, a local PID controller is tuned to each operating point and a supervisory strategy is proposed and applied to switch among these controllers accordingly to th e actual measured conditions. Each PID controller has been tuned off-line, by the combination of a dynamic recurrent non-linear neural network model w ith a pole placement control design. To reduce the number of local controll ers, to be selected by the supervisor, a c-Means clustering technique was u sed. Simulation and experimental results, obtained at Plataforma Solar de A lmeria, Spain, are presented showing the effectiveness of the proposed appr oach. (C) 1999 Elsevier Science Inc. All rights reserved.