| The shortage of energy is an important challenge the world is facing at present.The increasingly depleted of non-renewable resources makes the development of renewable resources imperative.Solar energy as the world’s largest renewable energy,the main problem is utilization inefficient.Heliostat technology is one of the key technologies of tower solar thermal power generation.The function of heliostat is the first step of solar energy transmission.Heliostat is to track,gather sunlight and accurately reflect it on the absorber.The operation,tracking and reflection quality of heliostats determine the power generation efficiency of tower power station.Due to the external factors and the heliostat itself,the error of the heliostat in the long-term operation results in the decrease of the condensing accuracy and the solar thermal conversion efficiency.Therefore,the heliostat accuracy of the sun is a more important parameter and only heliostat sun precision is high enough to ensure that the thermal power generation system has a higher light-to-heat conversion efficiency.This thesis mainly focuses on the research and implementation of related technologies in tracking process of heliostat tracking in the mirror field of solar power plant.The main tasks are as follows:(1)Sun movement law and heliostat sun-reflecting principle researchAccording to the moving trajectory of the sun,a solar motion model is established.And the solar trajectory was simulated on a specific date.According to the movement law of the sun combined with the principle of heliostat focusing and heliostat sunray reflection principle,the heliostat chasing reflection model is established.(2)Analysis on the error characteristics of heliostat sun-trackingThrough the analysis of the errors existing in the operation of heliostat and the modeling of the main errors affecting heliostat precision of heliostat is established,the error of heliostats reflected on the drift characteristic of reflected speckle is simulated.(3)Heliostat status detection and parameter soft sensorOn the basis of the analysis of the error characteristics,the field flare test is carried out on a single heliostat.The image processing technique is used to process the spot image and combined with the sensor’s measured data and the heliostat’s error is calculated according to the algorithm.(4)Heliostat closed-loop control design and testingFor the current heliostat open-loop control of the lower accuracy problem,a closed-loop control system which realizes heliostat operation attitude feedback by using MEMS equipment is established The heliostat attitude angle measurement has been experimentally verified. |
