Working principle and design of solar street lamp LED 065438+20081Friday, October 25th, 22:28 Foreword: With the aggravation of the world energy crisis, all countries are seeking solutions to the energy crisis, one of which is to seek the utilization of new energy and renewable energy; The second is to seek new energy-saving technologies to reduce energy consumption and improve energy utilization efficiency. Solar energy is the most direct, universal and clean energy on the earth. As a huge renewable energy, the radiant energy reaching the surface of the earth every day is about 250 million barrels of oil, which can be said to be inexhaustible. The spectrum of LED is almost concentrated in the visible light band, so the luminous efficiency is high. Generally speaking, energy-saving lamps can save 4/5 energy, which is a great innovation, but LED is more energy-saving than energy-saving lamps14, which is a greater reform of solid-state light sources. Solar LED lighting combines the advantages of solar energy and LED. In this paper, a solar LED high-power street lamp is discussed and introduced in detail, as shown in figure 1 and system introduction 1. The basic composition of the system is shown in Figure 2. The system consists of solar cell module (including bracket), LED lamp holder, control box (with controller and storage battery) and lamp post. The light efficiency of the solar panel reaches 127Wp/m2, with high efficiency, which is very beneficial to the wind-resistant design of the system. In the lamp holder part, 1W white LED and 1W yellow LED are integrated on the printed circuit board and arranged in a dot matrix at a certain distance as a plane light source. The control box is made of stainless steel, which is beautiful and durable; Maintenance-free lead-acid battery and charge-discharge controller are placed in the control box. The system adopts valve-controlled sealed lead-acid battery, which is also called "maintenance-free battery" because of its less maintenance, which is beneficial to reduce the maintenance cost of the system. The design of the charge and discharge controller considers the complete functions (including light control, time control, overcharge protection, overdischarge protection and reverse connection protection, etc.). ) and cost control to achieve high cost performance. The working principle of 1.2 is introduced. The working principle of the system is simple. During the day, the solar panel made of photovoltaic effect receives solar radiation energy and converts it into electric energy, which is stored in the storage battery through the charge-discharge controller. At night, when the illumination gradually decreases to about 10lux and the open-circuit voltage of the solar panel is about 4.5V, the charge-discharge controller detects this voltage value and acts, and the battery discharges the lamp holder. After the battery is discharged for 8.5 hours, the charge-discharge controller acts, and the battery is discharged. The main function of the charge-discharge controller is to protect the battery. 2. System design ideas Compared with general solar lighting, the basic design principles of solar street lamps are the same, but there are more links to be considered. The following will take this solar LED high-power street lamp of Hong Kong Li Zhenming Group Co., Ltd. as an example, and analyze it from several aspects. 2. 1 solar cell module selection design requirements: in Guangzhou, the load input voltage is 24V, the power consumption is 34.5W, the working time is 8.5h every day, and it is rainy for 7 consecutive days. (1) The average annual radiation in Guangzhou in recent twenty years is 65,438+007.7 kcal/cm2, and the peak sunshine hours in Guangzhou is about 3.424 h by simple calculation. ⑵ Daily power consumption of load =12.2 ah ⑵ Total charging current required by solar module = 1.05×12.2× (3.424× 0.85) = 5.9a The shortest design day between two consecutive rainy days here is 20 days, and1.05 is solar energy. (4) Minimum total power of solar cell module = 17.2×5.9 = 102W. The peak output power is 1 10Wp, and a single standard battery module with 55Wp should be able to ensure the normal operation of the street lamp system in most cases of a year. 2.2 battery selection The calculation of battery design capacity is simpler than the peak wattage in solar module. According to the above calculation, the daily electricity consumption of the load is 12.2AH, and the battery can work continuously for 7 rainy days when fully charged. Together with the work on the first night, the battery capacity is12.2× (7+1) = 97.6 (ah), two12v/kloc. 2.3 Design of the inclination angle of the solar module support 2.3. 1 In order to make the solar module receive as much solar radiation as possible in one year, we should choose an optimal inclination angle for the solar module. In recent years, there have been many discussions about the optimal inclination angle of solar cell modules in some academic journals. Street lamps are used in Guangzhou. According to the relevant literature of this design [1], the inclination angle of the solar cell module bracket is 16o. 2.3.2 Wind-resistant design In the solar street lamp system, a structural problem that needs great attention is wind-resistant design. The wind-resistant design is mainly divided into two parts, one is the wind-resistant design of the battery module bracket, and the other is the wind-resistant design of the lamp post. The following are analyzed according to the above two blocks respectively. (1) Wind-resistant design of solar module bracket According to the technical parameter data of the battery module manufacturer, the windward pressure that the solar module can bear is 2700Pa. If the wind resistance coefficient is 27m/s (equivalent to 10 typhoon), according to inviscid fluid mechanics, the wind pressure borne by the battery module is only 365Pa. So the module itself can withstand the wind speed of 27m/s without being damaged. Therefore, the design focuses on the connection between the battery assembly bracket and the lamp post. In the design of this street lamp system, the connection between the battery module bracket and the lamp post is fixed by bolts. ⑵ The wind-resistant design parameters of street lamp poles are as follows: the inclination angle of battery panel a =16o; The height of the lamp pole is 5 meters; Width of welding seam at the bottom of lamp post δ = 4 mm; The outer diameter of the light pole is168mm; As shown in Figure 3, the surface where the weld is located is the failure surface of the lamp post. The distance from the calculation point P of the resistance moment W of the damaged surface of the lamp post to the action line of the load F of the battery panel on the lamp post is PQ = [5000+(168+6)/Tan16o] × sin16o =1545mm =/kloc-. Considering the safety factor 1.3, F = 1.3×730 = 949N. Therefore, m = f×1.545 = 949×1.545 =1466 n.m. According to mathematical deduction, the resistance moment of annular failure surface w = π× (3R2δ+3Rδ 2+δ 3). In the above formula, r is the inner diameter of the ring and δ is the width of the ring. Resistance moment of sliding surface w = π× (3R2δ+3Rδ 2+δ 3) = π× (3× 842× 4+3× 84× 42+43) = 88768mm3 = 88.768×10-6m3 Stress caused by moment of wind load on sliding surface = m/. As long as the welding quality can be guaranteed, the wind resistance of the lamp post is no problem. 2.4 Controller The main function of the solar charge-discharge controller is to protect the battery. The basic functions must have the functions of overcharge protection, overdischarge protection, lighting control, time control and reverse connection prevention. See table 1 for general parameters of battery overcharge and overdischarge protection voltage. When the battery voltage reaches the set value, the state of the circuit will change. In the choice of devices, there are some single-chip computers and some comparators, and there are many schemes, each with its own characteristics and advantages. The corresponding scheme should be selected according to the needs of the customer base, so I won't elaborate here. 2.5 Surface Treatment This series of products adopt new technologies from electrostatic coating, mainly FP professional building materials coatings, which can meet customers' requirements for product surface color and environmental harmony. At the same time, the product has high self-cleaning, strong corrosion resistance and aging resistance, and is suitable for any climate environment. The processing technology is designed to coat on the basis of hot dip zinc, which greatly improves the product performance and meets the most stringent requirements of AAMA2605.2005, and other indicators meet or exceed the relevant requirements of GB. 3. Conclusion All links are considered in the overall design; The peak wattage selection design and battery capacity selection design of photovoltaic modules adopt the most common design methods at present, and the design ideas are scientific; The wind-resistant design is analyzed from two parts: battery assembly bracket and lamp post, and the analysis is comprehensive; Surface treatment adopts the most advanced technology at present; The overall structure of the street lamp is simple and beautiful; The actual operation proves that all links cooperate well. At present, the initial investment of solar LED lighting is still a big problem that puzzles us. However, the light efficiency of solar cells is gradually improving, and the price will gradually decrease. Similarly, the light efficiency of LED in the market is also increasing rapidly, but the price is decreasing. Compared with renewable, clean and pollution-free solar energy and environmental protection and energy saving of LED, conventional fossil energy is increasingly tense, which will cause increasingly serious pollution to the environment after use. Therefore, solar LED lighting, as a kind of outdoor lighting in the ascendant, will show us infinite vitality and broad prospects. References:
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