Research On Solar Tracking Control System

With the gradual shortage of fossil energy,the increasingly serious environmental pollution,and the continuous increase in per capita electricity consumption,today’s society is in dire need of a clean,renewable energy source to replace traditional fossil energy.Solar energy is gradually gaining attention because of its abundant,clean and renewable characteristics.In order to maximize the efficiency of solar energy utilization,solar photovoltaic panels or collector panels need to be perpendicular to the direction of direct sunlight,so the algorithms and devices for tracking and controlling the direction of sunlight have gradually become the focus of research on solar energy utilization.This paper takes the solar tracker as the research object,and firstly studies and analyzes the geometric installation error of the solar tracking controller,and then calculates the four-quadrant detector spot positioning error(including dead zone error and electrical noise error,etc.).The two-phase HB type stepper motor closed-loop control system is designed,and the position control performance analysis is done in MATLAB first,then the software and hardware system of the stepper motor drive controller is designed and applied to the motor drive control of the two-axis tracking device.Finally,a comparison experiment is done on two solar dish collectors to verify the tracking accuracy of different tracking methods.This paper mainly covers the following contents.1)The installation error study of the solar tracker device is carried out.According to the basic operation principle of the sun and the mechanical structure of the tracker,the mathematical geometric error model is built,and the azimuthal and altitude error values of the solar tracker are obtained by coordinate conversion under different installation offset angles,and the error variation curves are plotted according to the azimuthal and altitude angles at different latitudes and longitudes and different dates and times,which provide a theoretical basis for the subsequent design and implementation of the solar tracker.provide a theoretical basis for the subsequent design and implementation of the solar tracker.2)To study the positioning error of the end sensor of the sun tracker-the four quadrant detector.From the basic principle of spot positioning of the detector,the sources,characteristics and correction methods of the errors,including dead zone error,dark current noise error and photocurrent noise error,are studied in the solar tracking application.The spot positioning equation of the four-quadrant photodetector is derived to provide the theoretical basis for the use of this sensor in sunlight trackers.3)Simulation and hardware and software design of the control system of the two-phase HB type stepper motor drive controller are carried out.Firstly,the voltage equation,mechanical equation of motion and electromagnetic torque equation of the stepper motor are analyzed,and the motor vector control method and the corresponding control model are applied;the Simulink simulation control system model of the two-phase HB type stepper motor closed-loop control system is built,and the simulation analysis is mainly done for the discrete and continuous position control performance.Finally,the new stepper motor closed-loop drive controller is designed,including hardware and software system design,and then the motor closed-loop controller is applied to the motor on the solar two-axis tracking device.4)Perform the system design and experiment of the solar tracking controller.The two-axis turntable was selected as the tracking device of the tracker with a stepper motor driver,and the main controller and four-quadrant detector were added to form the solar tracker.On two identical solar dish collectors,control time,compare the same meteorological factors,using different tracking methods to do a comparative test of dish collector collector efficiency.