Entering the new century, the state has increased the construction of transportation systems, such as railways, highways, highways, high-speed rail and so on. The road is bound to not open around the tunnel, the tunnel must be installed in the light of the tunnel, which leads to the large-scale LED tunnel light industry. However, there are currently LED tunnel lamp manufacturers scale is not many, in addition to the Grand Canyon of Shanghai, Dongguan, Zhongshan KingSun Luna lighting a few professional LED tunnel lamp manufacturers, the other is not the size of the small factory.
LED tunnel lamp light source tunnel lamp with traditional incomparable advantages, energy saving, high brightness, high color rendering index, long life, small size and installation, especially in high power LED tunnel lamp, regardless of brightness or life of Dou Yuan than the traditional sodium lamp is the main flow tunnel lights, tunnel lamp products. Here we come to the LED tunnel lights and traditional tunnel lights to do a contrast.
1 Comparison between the function of the conventional tunnel lamp and the LED tunnel lamp
At present, the traditional tunnel lighting is the high-pressure sodium lamp as the light source, but in the form of radiation, high pressure sodium lamp color, visual sensitivity, power specifications, brightness control etc. there are many deficiencies, but the emerging LED tunnel lights, especially high power LED tunnel lamp with its excellent performance, especially the controllability of brightness and overcome the shortcomings of high pressure sodium lamp, the lamp is becoming mainstream in today's world of tunnel lighting. Country also introduced a "Ten City million" semiconductor lighting project of new initiatives for the development of LED tunnel lights has brought unprecedented opportunities. Zhongshan moon lighting as a positive response to the "ten city lights" plan, spare no money in Europe to introduce advanced LED tunnel lamp production equipment, strong R & D and production of new LED tunnel lamp, an important market share in the domestic LED tunnel lamp current.
LED (LightEmittingDiode) is a light-emitting diode, is a semiconductor light-emitting technology. The first developed LED can only emit red light, used for electronic devices in the indicator light. With the development of technology, now the LED lamp has been sent to all kinds of color lights, and is widely used in many industries, mainly including the traditional display application market and signal lamp market, backlight market, LED lights, LED tunnel lights, automotive lighting market, outdoor landscape lighting and decorative lighting, special lighting market market. LED light source as a tunnel has its unique advantages.
(1) LED tunnel lamp with low power consumption, energy saving, compared with the high pressure sodium lamp, energy saving more than 60%.
(2) the use of long life LED tunnel lights, with moon lighting high-power LED tunnel lamp as an example, the normal service life of 60 thousand hours or more, the service life of the lamp is more than 10 times.
(3) LED tunnel lamp good working stability, during the use of basic maintenance, and the maintenance cost is very high sodium.
(4) reduce the distribution system (cable, transformer, distribution box, bridge construction cost, etc.) for the long tunnel, long distance power supply, cable, distribution facilities accounted for the proportion of the cost especially large, using LED tunnel lamp because electricity can greatly reduce the cable and power distribution equipment investment.
(5) LED tunnel lamp can achieve instant start, easy to adjust the brightness, with no flicker, start a wide voltage range, can achieve a variety of ways such as, according to the traffic flow, intelligent road tunnel illumination control etc.. The new moon lighting LED tunnel lamp can realize remote control, time control and other intelligent control.
(6) high pressure sodium lamp, fluorescent lamp, electrodeless lamp contains mercury, lead and other chemical pollutants, and LED tunnel lamp light source does not contain chemical pollutants, is light green. The moon lighting LED tunnel lamp through the European ROHS certification standards, is harmless to the environment is a prerequisite to enter the European market.
2 high power LED tunnel lamp design requirements
(1) the basic lighting should be set up either during the day or at night. During the day, when the vehicle enters the tunnel, the brightness of the road surface should be decreased gradually, so that the driver's vision has an adaptation process, and the entrance section is divided into the introduction section, the adaptation section and the transition section.
(2) introduction section, to determine the section and transition section length (S), usually according to the vehicle speed (V) determined by T=2s adaptation time, S=VT/3.6m can be used to estimate; exit section should also transition lighting, in two-way traffic conditions and the same entrance.
(3) the night entrance is not set up to strengthen the lighting, street lighting should be set out, not less than the basic brightness brightness of 1/2; the tunnel should be equipped with emergency lighting, its brightness is not less than the basic brightness 1/10.
(4) according to the provisions of China JTJ026-90 "highway tunnel design code", the length of the tunnel entrance lighting range and the minimum standard of road surface are designed according to the requirement of table 1.
3 high power LED tunnel lamp design
Selection of 3.1LED light source
Watt LED single lumen output is the basic index, determine whether the LED tunnel lamp has practical value in accordance with the requirements of the number of single tile lumen LED used LED tunnel lights should reach more than 100 lumens, in the rapid development of nearly three years after the luminous efficiency of the LED stage, Luna LED light efficiency lighting can supply large quantities of has reached more than 120-130lm/W, and constantly improve the brightness. Table 2 provides the main technical parameters of the large power 1W white LED, which represents the major manufacturers of the world's leading edge at present. OSRAM can be used for the design of LUWW5AM light source manufacturers, the use of LED light source has the characteristics of a variety of different color temperature can be selected, select the LED light source with similar fluorescent color temperature 4000~6000K, can effectively reduce the "light hole" and "black hole" effect.
3.2 light distribution design
According to the requirements of tunnel lighting, lighting in different periods with different light lamps, based on optical principle and LED light source with high directivity characteristics, the light distribution reasonable, in order to meet the requirements of the luminance or illuminance, reduce the lamp power, achieve the purpose of energy saving. The latest LED tunnel lamp with horizontal light distribution, more suitable for road lighting demand in the narrow tunnel.
(1) the introduction of the import section, the tunnel section to section and transition section and exit section of the asymmetric distribution of light illumination (light lighting), illumination in the same conditions, compared with ordinary lighting, can improve the surface brightness of 121%, at the same time, with the advantages of high directivity, the intensity of strict control of large angle direction the elimination of most glare.
(2) in the basic section of the tunnel, the common light distribution type concentrating light distribution, side emitting light distribution, Lambertian light etc.. Different applications for different light distribution forms, such as road lighting should be selected to bat wing light distribution, light concentrating light distribution should be selected. Because of the particularity of the tunnel lighting, tunnel lighting lamp density is very high, so in the tunnel lighting two light distribution form of the lighting is different from ordinary road lighting. In the tunnel lighting bat wing light distribution, Lambert light distribution can meet the illumination uniformity requirements, mainly due to the relatively small distance tunnel lighting lamp. C0 direction Figure 1 shows the two LED tunnel light distribution map, left for the bat wing light distribution commonly used in road lighting, tunnel lighting, the right for the Lambertian light distribution. With bat wing light distribution, wide band symmetrical illumination with light illumination in the same conditions, compared with ordinary lighting, can improve the surface brightness of 64%, improve the surface brightness uniformity.
3.3 heat sink design
LED is a photoelectric device, to the world's leading edge in the high power LED, the work process is only 15%~20% electric energy into light energy, and the rest of the electric energy conversion into heat, so that the temperature of LED. On the other hand, the LED lumen output decreases with increasing the junction temperature of LED, and LED with the increase of junction temperature and shorten the life of. Therefore, the heat treatment of LED will be directly related to the use of the tunnel lighting effects and life.
The cooling of high power LED are mainly in three ways: natural cooling, installation of fan forced cooling and heat pipe and heat sink technology etc.. Natural convection and heat radiation, the structure is reliable and easy to do waterproof, but the structure design of the light body is high. The installation of fan forced cooling mainly uses forced convection to achieve heat dissipation, heat dissipation rate is fast, but the cost and noise is high, it is difficult to do waterproof. The heat pipe and radiating fin technique using heat pipe heat generated by the LED will quickly transfer to the radiating fins and reach the purpose of cooling, no moving parts, the system is stable, but the cost is relatively high.
As compared with general road tunnel, has its unique properties, we adopt the heat pipe and heat sink technology of heat treatment, heat channel of vertical design, implement a modular approach to the LED junction temperature is maintained at 70 DEG C, ensure the stability of LED long time working under low light decay, improve lighting maintenance coefficient save the maintenance cost.
According to the flow characteristics of the airflow in the tunnel, the asymmetric ventilation design of the radiating cavity, protect air convection, while reducing automobile fumes generated such as dirt into the cooling chamber, adsorbed on the heat dissipation structure caused heat efficiency.
3.4 structure design
Light weight aluminum alloy shell, light weight in 10kg. LED light source cavity and the electrical cavity protection level according to the IP65 design, the heat radiation cavity according to the IP23 design; the light source cavity and the heat radiation cavity uses the reasonable isolation way, avoids the light source cavity and the heat flux heat flux mutual influence. Because of the tunnel air circulation, automobile exhaust doped them, complex composition, so LED tunnel lamps should have other chemical corrosion resistance, good air, smoke and exhaust gas in a tunnel containing, each structural component surface for anti-corrosion treatment, the GB/T7000.5 of the corrosion protection requirements.
3.5 circuit design
LED positive volt ampere characteristics and ordinary diode forward voltage is similar, plus a slight change, the positive current will change greatly, resulting in LED internal loss and fever is rising fast, seriously affect the normal work and life of LED. In order to prevent this kind of situation, high power LED generally must use the constant current mode power supply. In order to improve the efficiency, reduce the heating current source, the input voltage of the current source must be reasonably controlled, so that the maximum value after deducting the internal pressure drop after the same current, but also match the total voltage required by LED. The internal loss is small, and the reliability of the current source can be guaranteed.
Tunnel lighting generally requires a large number of lamps, the power consumption is huge, to save energy and reduce the grid's "pollution", LED tunnel lamp driver also requires the power factor and harmonic generation must meet the requirements of relevant standards, and consider the electromagnetic interference and electromagnetic compatibility.
(1) power supply with high conversion efficiency, high stability, conversion efficiency is greater than 87%, power factor greater than 95%, the switching power supply voltage fluctuation resistance capacity of external strong power grid (96~264V), with the constant current circuit design, constant current LED driver source, ensure the service life of LED.
(2) the use of the tunnel lighting control circuit, so that light and light in the tunnel for different lighting and different time periods for the power of the adjustment, to achieve good lighting and energy efficiency. The inlet section of the tunnel entrance section, section, transition section and adapt to the outlet section using different current drive, make it as close as possible to the tunnel illumination curve, achieve the best lighting effects; of inlet section tunnel and exit section of the timing adjustment function, by adjusting the output current of PWM dimming or a dual power supply at night, with a single power supply, the power is reduced to 50% day lighting, both at day and night, can effectively reduce the "bright hole" and "black hole" phenomenon.
4 Conclusion
Development and production of high-power LED tunnel lighting light source design application, add wide for the national railway, highway tunnel lighting market, it is not only for the application of our new light tunnel to fill the gaps, but also in low carbon energy saving and environmental protection of the road and a step forward, is a comprehensive application. The Grand Canyon, Qinshang, Luna lighting LED tunnel lamp enterprises, will lead in this market in skill, continuous research and development to produce LED tunnel lights, more advanced country, for the benefit of society.
