Researches On Heliostats Concentrating And Imaging Strategy And Control System In Solar Power Tower System

Concentrating Solar Power (CSP) technology is one of the effective ways to solve environmental pollution and ecological destruction problems in the 21st century. CSP technologies exist in three common forms, namely parabolic trough, dish Stirlings and solar power tower, in which solar power tower is the most economical form. The researches of CSP technologies abroard started in the 1970's and have made many achievements. However, the relative researches in the CSP field started late in China. In the solar power tower system, to achieve the high-precision control of the mass heliostats is a key problem restricting its application in China. This work mainly focuses on the researches of concentrating strategy, imaging simulation and designing of the control system in terms of the mass heliostats control for the solar power tower technology and makes explorations as follows.First, the solar motion model is established based on geometric optics theories. A sun positioning algorithm is designed and fulfilled through simulations. This work also designed an automatic apparatus for measuring the sun position.Second, this work achieves heliostats modeling for the solar power tower technology. Based on the dynamics of machinery and Eulerian angles matrix theories, an ideal two-axis heliostat model which is a three-dimensional motion system is built. Then proposed a solar concentrating algorithm for the heliostats. Through simulations and experiments of the concentrating algorithm, the changing disciplines, error analysis of heliostat angels and sun position are concluded.Third,, this work proposes a geometric imaging model of the heliostat reflection. This model is simulated and tested to achieve imaging disciplines in circumstances of different time and different reflection positions.Fourth, overall control solutions are proposed for the mass heliostats fields. In the solutions, distributed management for the heliostats field is proposed. Moreover, time-division communication mechanism and modular integration are designed for the control system.The heliostats concentrating strategy and imaging model are verified to be feasible and with high-precision through simulations and experiments. Moreover, the overall plan of the control systems is suitable for the solar power plant which consists of mass heliostats, and highlights the features as simple structure, good reliability, rational design and convenient maintainance. The conclusions of this thesis lay a foudation to achieve the high-precision and high-efficiency control of the mass heliostats for the solar power tower technology.