This paper approaches a dual-axis equatorial tracking system that is used to increase the photovoltaic efficiency by maximizing the degree of use of the solar radiation. The innovative aspect in the solar tracker design consists in considering the tracking mechanism as a perturbation for the DC motors. The goal is to control the DC motors, which are perturbed with the motor torques whose computation is based on the dynamic model of the mechanical structure on which external forces act. The daily and elevation angles of the PV module represent the input parameters in the mechanical device, while the outputs transmitted to the controller are the motor torques. The controller tuning is approached by a parametric optimization process, using design of experiments and response surface methodology techniques, in a multiple regression. The simulation and experimental results demonstrate the operational performance of the tracking system.

This article presents the virtual prototype of the tracking system used for improving the energetic efficiency of a photovoltaic panel. From the point of view of the efficiency and safety, a polar dual-axis system has been designed. Both motions (daily and seasonal) are driven by rotary actuators, which are coupled with worm gears for blocking the system in the stationary positions. The tracking system is approached in mechatronic concept, by integrating the mechanical structure of the solar tracker and the electronic control system at the virtual prototype level. The tracking strategy aims at reducing the angular field of the daily motion and the number of actuating operations, without significantly affecting the incoming solar energy. At the same time, an algorithm for determining the optimal actuating time for the step-by-step tracking is developed. For performing the energy balance, the incident solar radiation is obtained using a method based on the direct radiation and the angle of incidence, while the energy consumption for accomplishing the tracking is determined by simulating the dynamic behaviour of the solar tracker. Finally, the validation of the simulation results is performed by comparing the virtual prototype analysis with the data achieved by experimental measurements.

This paper approaches the optimal design of the mono-axial tracking system used for a string of photovoltaic (PV) modules. The tracking mechanism is designed in a CAD (Computer Aided Design) environment (SolidWorks), the solid model being then transferred in the dynamic analysis and optimization environment (adams/View). The control system is designed with adams/Controls and matlab/Simulink, in mechatronic concept, by integrating the mechanical device and the control system at the virtual prototype level. The control method is based on a single-open-loop model with PID (Proportional-Integral-Derivative) controller, having as input the daily angle of the PV string. The output from the control system (i.e., the input in the mechanical device model) is the motor torque developed by the rotary actuator that drives the system. The tracking program has been developed by using an empirical model of the solar irradiation, obtaining the optimal angular field for the daily motion, the number of motion steps, and the actuating time. The optimization purpose is to minimize the tracking error, the design objective's value being the root mean square during simulation. The specific parameters of the PID controller are used as design variables in the optimization process. The investigation strategy is based on a design of experiments technique, obtaining the appropriate regression function. Finally, the physical prototype is developed and tested in real environment, the experimental results being used to validate the virtual prototyping-based simulation.

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