The Study Of Computer Controlled Two-Axis Solar Tracking System And Its Error Measurement

As renewable energy, solar energy has the advantages of environment-friendly and sustainable for utilization. During the process of solving the traditional energy crisis, many countries focus their eyes on exploitation and research of solar energy. Yet it also has the disadvantages such as low density, discontinuous and asymmetric distributing, which causes the two primary problems in the field of solar application, how to improve the solar utilization rate of the solar power systems, and how to reduce the building costs of the power system. The solar tracking device gives the possibility of solving these problems. On the one hand, using solar tracking device, we can improve the utilization rate of the solar energy by reducing the incidence angle between the incidence beam and the solar battery array. On the other hand, with this device, we can use the method of concentrating sun's rays to improve the density of solar energy to increase the conversion ratio of the generating electricity system, and to decrease the quantity of the costly solar batteries in the system to cut down the building costs of the system. With people attaching more and more importance to the exploitation and utilization of the solar energy, it's very realistic to research the system of the solar tracking device.Based on the solar position geometrical model, this paper has set up the two-axis solar tracking motion control equation of the sun moving trajectory tracking on the method of vector analysis, analyzed the motion characteristic and done the systematic theoretical research and simulation on the intermittent tracking control method; on the basis of which, adopted "PC + motion control card" strategy to control the stepper motor with closed-loop feedback , designed and trial-manufactured the two-axis solar tracking system, produced a whole computer motion control software based on the technology of virtual instrument, and finally completed the electrical and mechanical debugging of the system. At present, the system has been used in a certain national 863 project successfully, which runs normally, adjusts flexibly, operates conveniently and with a friendly software interface. The theory of measuring the solar tracking error with four-quadrant PV cell has been put forward for the first time to estimate and supervise the tracking error of the two-axis solar tracking device. And then, its theory of measurement has been researched and the device has been designed and trial-manufactured. In the end, some experiments have been done to validate the fact. The outcome of the experiments showed that the motion disciplinarian can be reflected preferably and the tracing error of the system can be detected sensitively with this method. The technology of using four-quadrant PV cell is viable.