An input-to-state stabilizing discrete-time adaptive control scheme for concentrating solar power systems

The development of advanced solar thermal parabolic trough collectors fields for electrical power generation calls for the conception of simple but effective temperature control strategies capable to cope with the nonlinearities and the uncertainties that typically affect this kind of plants, which are mainly due to the variability of thermal and optical parameters among the collector modules. For plants in which multiple temperature measurements are available for each string of collectors, as in the case of the molten-salt technology under exam, an adaptive control strategy is proposed. It relies on the combined use of a discrete-time nonlinear model-based controller with an on-line parameter adaptation mechanism based on error-projection. Under a persistency of excitation assumption, the input-to-state stability of the resulting c-l system with respect to bounded unstructured uncertainties can be proven. Simulation results show that the proposed control policy allows to effectively control the plant in various operating scenarios.