LED street light is different from conventional street light. The LED light source is low-voltage DC power supply, high-efficiency white light synthesized by GaN-based power type blue LED and yellow. It has high efficiency, safety, energy saving, environmental protection, long life, fast response, high color rendering index, etc. Unique advantages can be widely applied to roads. The cover can be made with high temperature resistance up to 135 degrees and low temperature resistance up to -45 degrees. LED street light design has the following requirements: 1. The most important feature of LEDs for illumination is the function of directional emission of light, because power LEDs are almost always equipped with reflectors, and the efficiency of such reflectors is significantly higher than the reflector efficiency of the lamps. In addition, the efficiency of the self-reflector has been included in the LED efficacy detection. Road luminaires using LEDs should utilize the characteristics of directional emitted light of LEDs as much as possible, so that each LED in the road luminaire directly directs the light to each area of ​​the road surface to be illuminated, and then uses the auxiliary light distribution of the luminaire reflector to realize Very reasonable light distribution for road lamps. It should be said that the road lamps should meet the requirements of illumination and illumination uniformity of CJJ45-2006 and CIE31 and CIE115 standards. The function of three light distributions in the lamps should be better. An LED with a reflector and a reasonable beam output angle has a good primary light distribution. In the luminaire, a good secondary light distribution function can be realized by designing the mounting position of each LED and the direction of the emitted light according to the height of the road lamp and the width of the road surface. Reflectors in such luminaires are only used as an auxiliary three-time light distribution to ensure better uniformity of road illumination. In the design of the actual road lighting fixtures, each LED can be fixed on the luminaire with the spherical universal joint under the premise of basically setting the direction of each LED, when the luminaire is used at different heights and illumination widths. At the same time, the spherical gimbal can be adjusted to achieve satisfactory results for each LED. When determining the power and beam output angle of each LED, the LEDs can be calculated according to E(lx)=I(cd)/D(m)2 (the inverse law of the intensity and illuminance distance). The power that the beam should have when outputting the angle, and the light output of each LED can be predicted by adjusting the power of each LED and the different power output from the LED driver circuit to each LED. These adjustment methods are unique to road lamps that use LED light sources. By fully utilizing these features, it is possible to reduce the illumination power density and achieve energy saving while satisfying the illumination and uniformity of road surface. 2. The power system of LED street light is different from the traditional light source. The constant current driving power supply required by LED is a cornerstone to ensure its normal operation. The simple switching power supply scheme often brings damage to LED devices. How to make a group of LEDs tightly compressed together is also an indicator of LED street lights. The requirement of the LED for the driving circuit is to ensure the characteristics of the constant current output. Because the relative change region of the junction voltage is small when the LED is working in the forward direction, the constant driving current of the LED ensures that the output power of the LED is constant. For the current situation of unstable supply voltage supply in China, it is necessary to have a constant current output characteristic of the driving circuit of the road lamp LED, which can ensure the light output is constant and prevent the super power operation of the LED. In order to make the LED drive circuit exhibit constant current characteristics, the output internal impedance must be high when viewed from the output end of the drive circuit. During operation, the load current also passes through the output internal impedance. If the drive circuit consists of buck, rectification and filtering, plus DC constant current source circuit or general-purpose switching power supply plus resistance circuit, it must consume a lot of active power. Power, so the two types of drive circuits under the premise of basically meeting the constant current output, the efficiency is impossible. The correct design scheme is to use an active electronic switching circuit or to use high-frequency current to drive the LED. The above two schemes can make the driving circuit still have high conversion efficiency while maintaining good constant current output characteristics. China's road lamps basically adopt the mode of HID light source with trigger and magnetic ballast. Although this mode has the problems of low energy efficiency and stroboscopic. While LED lamps using electronic drive circuits are used in field lighting applications, an important aspect that threatens their plasticity is the lightning induction problem. It is well known that lightning in the air emits a broad spectrum of radio waves, while overhead road lighting power lines are well accepted for wireless. The radio waves emitted by the same lightning output received by the two power lines belong to the common mode interference signal for the driving circuit. The common mode interference can reach several volts to several thousand volts, which easily breaks through the driving circuit. The EMC grounding capacitor or a small clearance to the ground (to the outer casing) causes damage to the drive circuit. In addition, since the power supply line in China is a three-phase four-wire neutral line grounded polar power supply, in the segments of the two overhead power supply lines, at the moment when the radio waves of the lightning are sensed, the two power supply lines are grounded. The instantaneous impedance is different, which causes a differential mode interference voltage between the two power supply lines. The instantaneous differential mode interference voltage can also reach hundreds of volts to more than 3,000 volts. This voltage often breaks down the power supply rectifier diode and the printed circuit of the driver circuit. The electrical gap between the electrodes of different polarity on the board, the LED controller will also damage the drive circuit. To solve this problem, it is necessary to connect the fast-responding varistor to the input terminal of the LED driving circuit to ensure the leakage of differential mode interference. Since the inductive interference of lightning is repeated many times, when the interference voltage is high, the current of the varistor transient conduction bleed may be large, so the varistor should not only have a fast response capability, but also have a transient guide. The venting capacity of ten amps is not damaged. In addition to the use of varistor, the input of the LED driver circuit should also be combined with conducted interference (EMI) protection, designed with a composite LC network, so that these LC networks can not only hinder internal EMI leakage to the grid, but also The interference signal of lightning has a significant inhibitory effect. In addition, the electrical clearance of each point-to-ground of the LED driver circuit should be kept above 7mm. The grounding capacitance of the EMI protection and the insulation strength of the grounding circuit of the driving circuit should meet the requirements of reinforced insulation (4V+2750V), which can make the LED The drive circuit has good resistance to differential mode and common mode lightning induction. China IOT Conference Series [The 3rd China LED Intelligent Lighting Innovation Application Summit Forum ] will invite Zigbee Alliance, WiFi, Bluetooth and 2.4G technology major supplier executives to share their market insight and latest development results, I hope you can grasp This rare opportunity to exchange, find better business opportunities, and find a higher partner. Dc Gear Motor,Geared Motor,Dc Gear Motor 12V,Low Speed Gear Motor Changzhou Sherry International Trading Co., Ltd. , https://www.sherry-motor.com
