LED street lamp design standards and lighting requirements analysis
LED street lights and conventional street lamps is different, LED light source with low voltage DC power supply, by the GaN-based power-type blue LED and yellow synthesis of high efficiency white, with high efficiency, safety, energy saving, environmental protection, long life, fast response, high color rendering index Unique advantages can be widely used in roads. Cover available production, high temperature of 135 degrees, low temperature -45 degrees. LED street lamp design has the following requirements:
The most important feature of LED lighting is the function of directional emission light, because the power LED is almost always equipped with a reflector, and the efficiency of this reflector are significantly higher than the lamp reflector efficiency. In addition, LED light efficiency detection has been included in the efficiency of its own reflector. LED road lighting should be used as far as possible the use of LED directional light emission characteristics, so that the road lamps in the LED were directly directed to the light through the various areas of the road, and then use the lamp reflector auxiliary light, to achieve Very reasonable road lighting integrated light distribution. It should be said that the road lamps to be truly in line with CJJ45-2006 and CIE31 and CIE115 standard illumination and illumination uniformity requirements, the lamp should contain three times the function of light distribution can be better achieved. And with a reflector and has a reasonable beam output angle of the LED itself has a good light distribution function. In the lamp, according to the height of the road lighting and the width of the road design of the LED installation location and the direction of the launch light can achieve a good secondary light distribution function. Reflectors in such lamps, only as auxiliary three light distribution means, to ensure greater uniformity of road illumination.
In the actual design of the road lighting, you can use the basic set in the direction of each LED set under the premise of each LED with a spherical universal joint fixed on the lamp, when the lamps used in different height and irradiation width, can be adjusted by the spherical universal joint so that the direction of each LED to achieve satisfactory results. In determining the power of each LED, the beam output angle, according to E (lx) = I (cd) / D (m) 2 (light intensity and illumination distance square inverse law), respectively, the LED in the basic selection The beam output angle should have the power, and can be adjusted by the LED power and LED driver circuit output to each LED different power to make each LED light output to achieve the expected value. These adjustment methods are the use of LED light source of the road lamps unique, and make full use of these features can be achieved in the road to meet the road illumination and illumination uniformity under the premise of reducing the lighting power density, to achieve the purpose of energy conservation.
LED street lights power system is also different from the traditional light source, LED special constant current drive power is to ensure its normal work of a cornerstone, a simple switching power supply program often bring LED device damage. How to make a tightly packed together a group of LED security, but also an indicator of LED street lights. LED on the drive circuit requirements is to ensure that the characteristics of constant current output, because the LED forward work when the junction voltage relative to the region is very small, so to ensure that the LED drive current is also a constant guarantee of LED output power is constant. For China's power supply voltage supply instability of the status quo, road lighting LED drive circuit with constant cur
rent output characteristics is necessary to ensure that the light output is constant and to prevent the LED super power operation.