Fresnel Solar Collector Control With Active Defocus

Line focus concentrating solar collectors control operates by manipulating the flow for tracking the desired outlet temperature under normal conditions. This solar collector can also use the solar tracking device to manipulate the mirror's angle for defocusing under abnormal events. Defocusing mirrors is the last control measure to avoid overheating because defocusing means wasting energy. This work proposes changing the defocus use as the last control resort for safety, to a standard manipulated variable combined with the flow for outlet temperature tracking. The proposal uses a multi-variable non-linear MPC technique with a modified objective function and simulates three scenarios on a Fresnel solar collector. Besides, this paper indicates that the defocus action is necessary for regular operation; thus, it is also essential to consider the defocus as a manipulated variable for controller design. The proposed controller tracks reference and rejects disturbances while having defocus minimization, overheating prevention, and thermal power reference tracking features.