In central receiver systems, there are local controls that modify the position of the heliostats, where the trend is to increase the intelligence of the local controls in order to give them greater autonomy from the central control. This document describes the design and construction of a SCADA (Supervisory Control and Data Acquisition)-based heliostat control system (HCS) with a fuzzy logic controller (FLC) for the orientation control. The HCS includes a supervisory unit with a graphical user interface, a wireless communication network, and a stand-alone remote terminal unit (RTU) implemented on a low-cost microcontroller (MCU). The MCU uses a solar position algorithm with a maximal error of 0.0027 • in order to compute the position of the sun and the desired angles of the heliostat, according to a control command sent by the supervisory unit. Afterwards, the FLC orients the heliostat to the desired position. The results show that the RTU can perform all the tasks and calculations for the orientation control by using only one low-cost microcontroller with a mean squared error less than 0.1 • . Besides, the FLC orients the heliostat by using the same controller parameters in both axes. Therefore, it is not necessary to tune the controller parameters, as in the traditional PID (Proportional-Integral-Derivative) controllers. The system can be adapted in order to control other two-axis solar-tracking systems.

This paper describes the design and implementation of a heliostat orientation control system based on a low-cost microcontroller. The proposed system uses a fuzzy logic controller (FLC) with the Center of Sums defuzzification method embedded on a dsPIC33EP256MU806 Digital Signal Processor (DSP), in order to modify the orientation of a heliostat by controlling the angular position of two DC motors connected to the axes of the heliostat. The FLC is compared to a traditional Proportional-Integral-Derivative (PID) controller to evaluate the performance of the system. Both the FLC and PID controller were designed for the position control of the heliostat DC motors at no load, and then they were implemented in the orientation control of the heliostat using the same controller parameters. The experimental results show that the FLC has a better performance and flexibility than a traditional PID controller in the orientation control of a heliostat.