In order to utilize the solar energy more fully and efficiently, the way of tracking the sun is now commonly used to maximize the output power. On this basis, a dual-axis solar power tracking system with high tracking accuracy, simple structure and reliable control is designed, which effectively improves the utilization rate of solar energy.
Ⅰ. The use of solar power tracking system
With the development of modern industry, the problem of global energy crisis and air pollution has become increasingly prominent. Solar energy, a clean and renewable energy source, has been highly valued and utilized by many countries.
It can be known from the characteristics of the solar panel that its power generation is proportional to the light intensity irradiated on it, and the maximum light intensity of the sun can be obtained by receiving direct sunlight from the sun.
Tests have shown that with the same power of solar panels, the automatic tracking photovoltaic power generation equipment can increase the power generation by at least 25% compared with the fixed photovoltaic power generation equipment, and reduce the cost by 20%.
Since the position of the sun is changing all the time, if you want to get the maximum output power on the solar panel, it is necessary for the solar panel to follow the movement of the sun at any time, so as to ensure that the sunlight always shines vertically on the solar panel. In order to achieve the purpose that the sunlight always irradiates the solar panel vertically, it is necessary to use the automatic sunlight tracking control system to complete it.
Ⅱ. Control method of solar power tracking system
There are three commonly used solar tracking control methods: uniform speed control method; light intensity control method; space-time control method.
1. Uniform speed control method
Since the rotation speed of the earth is fixed, it can be considered that in the morning, the sun rises from the east and moves westward and sets in the direction of due south. The altitude angle is equal to the local latitude as a polar axis does not change. The tracking process is to rotate the solar panel fixed on the polar axis at the speed of the earth's rotation angular velocity of 15°/h, so as to achieve the purpose of tracking the sun and keeping the plane of the solar panel perpendicular to the sun's rays. This method is simple to control, but difficult to install and adjust, and the initial angle is difficult to determine and adjust. It is greatly affected by factors such as seasons, and the control accuracy is poor.
2. Light intensity control method
When tracking the altitude and azimuth angle, two photosensitive cells are respectively used as the sensitive elements of the sun position. Four photosensitive cells were installed in a light-transmitting glass test tube. Each pair of photosensitive cells is separated by a middle partition and placed symmetrically on both sides of the partition. When the panel is aligned with the sun, the sunlight is parallel to the separator, the two photosensitive cells have the same amount of light, and the output voltage is the same.
When the sunlight is slightly shifted, the shadow of the separator falls on one of the photosensitive cells, so that the photosensitive amounts of the two photosensitive cells are not equal, and the output voltages are not equal. The solar tracking control is carried out according to the change of the output voltage. The characteristics of this method are high measurement accuracy, simple circuit and easy implementation, but there will be problems of untracking in cloudy and cloudy environments.
3. Space-time controls the orbit of the sun, which is related to many complex factors such as time, season, local latitude and longitude
Therefore, the above-mentioned relevant data can be input into the microprocessor in advance, and the program can look up the table and calculate the sun azimuth and altitude to achieve time and space synchronization, and finally obtain the actual angle to achieve precise control. The method has high precision and good adaptability, but the program is complicated and not easy to implement.
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