As a key component of LED street lamps, the quality of LED drivers directly affects the reliability and stability of the overall lamps. If the LED street lamp driver is damaged, it will lead to low efficiency of the lamp and even unstable operation. So what can cause damage to the LED street lamp driver? We roughly have the following analysis:1. Aging of electronic componentsIncluding resistors, capacitors, diodes, transistors, LEDs, connectors, ICs and other devices such as open circuit, short circuit, burnout, leakage, functional failure, unqualified electrical parameters, unstable failure and other failure problems.2. PCB quality issuesIncluding PCB, PCBA, poor wetting, cracking, delamination, CAF, open circuit, short circuit and other failure problems.3. Poor heat dissipation of the LED power supplyThe driving circuit is composed of electronic components, and a few components are very sensitive to temperature. Such as electrolytic capacitors, the prevailing formula for estimating the life of electrolytic capacitors is "every 10 degrees lower in temperature, the life will double". Poor heat dissipation may greatly shorten its life and premature failure, leading to LED voltage failure and lamp failure. Especially for the built-in power supply (the power supply placed in the whole lamp), a power supply with a large amount of heat will increase the heat conduction and heat dissipation pressure of the whole lamp, the temperature of the LED will increase, and its light efficiency and lifespan will be greatly reduced. Therefore, when designing the LED power supply, it should pay attention to its own heat dissipation problem. Therefore, the above problems can be solved by carrying out the evaluation at the beginning of the design of the lamp and the design of the power supply simultaneously. In the design, it is necessary to comprehensively consider the heat dissipation of the LED and the power supply, and control the heating of the lamp as a whole, so that a better lamp can be designed.4. Problems in power supply design(1) Power design. Although the LED has high luminous efficiency, there is still 80%-85% heat loss, resulting in a temperature rise of 20-30K inside the lamp. If the room temperature is 25℃, the inside of the lamp will be 45-55℃. The power supply is in a high temperature environment for a long time. In order to ensure the service life, the power margin must be increased. Generally, a margin of 1.5 to 2 times is retained.(2) Component selection. When the internal temperature of the lamp is 45～55℃, the internal temperature rise of the power supply is about 20℃, and the temperature of the component accessories should reach 65～75℃. Some components will drift at high temperatures and even shorten their lifespan. Therefore, the components should be selected for long-term use at higher temperatures, and special attention should be paid to electrolytic capacitors and wires.(3) Electrical performance design. The switching power supply is designed for LED parameters, mainly constant current parameters. The size of the current determines the brightness of the LED. If the batch current error is large, the brightness of the entire batch of lights will be uneven. Moreover, temperature changes can also cause the power supply output current to shift. Generally, the batch error is controlled within ±5% to ensure that the brightness of the lamp is consistent, and the forward voltage drop of the LED is biased. The constant current voltage range of the power supply design should include the voltage range of the LED. When multiple LEDs are used in series, the minimum voltage drop multiplied by the number of series connection is the lower limit voltage, and the maximum voltage drop multiplied by the number of series connection is the upper limit voltage. The constant current voltage range of the power supply is slightly wider than this range. Generally, the upper and lower limits are set to 1~ 2V headroom.(4) PCB layout design. The size of the LED lamps reserved for the power supply is small (unless the power supply is external), so the PCB design requirements are higher, and there are more factors to be considered. The safety distance must be sufficient, and the power supply that requires input and output isolation, the primary circuit and the secondary circuit require a withstand voltage of 1500 ~ 2500 VAC, and a distance of at least 3 mm must be left on the PCB. If it is a lamp with a metal shell, the layout of the entire power supply should also consider the safe distance between the high-voltage part and the shell. If there is no space to ensure a safe distance, other measures must be used to ensure insulation, such as punching holes in the PCB, adding insulating paper, and potting insulating glue. In addition, the layout of the board should also consider the heat balance, and the heating elements should be evenly distributed and cannot be placed in a concentrated manner to avoid local temperature rise. Keep the electrolytic capacitor away from the heat source to slow down the aging and prolong the service life.5. Lightning damageLightning strikes are a common natural phenomenon, especially in the rainy season. The damage and loss it brings is calculated in hundreds of billions of dollars every year worldwide. Lightning strikes are divided into direct lightning strikes and indirect lightning strikes. Indirect lightning mainly includes conductive lightning and induced lightning. Since the energy impact brought by direct lightning is very large and its destructive power is extremely strong, the general power supply cannot withstand it, so the main discussion here is the indirect lightning type.The surge impact formed by lightning strikes is a kind of transient wave, which belongs to transient interference, which can be a surge voltage or a surge current. Along power lines or other paths (conducted lightning) or through electromagnetic fields (inductive lightning) and transmitted to the power line. Its waveform is characterized by a rapid rise first and then a slow fall. This phenomenon will have a fatal impact on the power supply. The instant surge impact it produces far exceeds the electrical stress of ordinary electronic devices, and the direct result is the damage of the electronic components.6. The grid voltage exceeds the power loadWhen the grid branch wiring of the same transformer is too long and there are large-scale power equipment in the branch, when the large-scale equipment starts and stops, the grid voltage will fluctuate sharply, and even cause the grid to be unstable. When the instantaneous voltage of the grid exceeds 310 VAC, the drive may be damaged (even if there is a lightning protection device, it is invalid, because the lightning protection device is to deal with pulse spikes of tens of microseconds, and the grid fluctuation may reach tens of milliseconds, or even hundreds of milliseconds) . Therefore, special attention should be paid when there are large electrical machinery on the street lighting branch power grid. It is best to monitor the fluctuation range of the power grid or use a separate grid transformer to supply power.7. Solder joint failurePower packaging mainly involves the connection process between the PCB board and the components, in which solder joints play an important role. The main function of solder joints is to realize the mechanical and electrical connection between electronic components and the substrate (PCB board in the LED power supply). The quality of solder joints seriously affects the reliability of the device. On the one hand, solder joint failure comes from soldering faults in production and assembly, such as solder bridging, virtual soldering, voids, and Manhattan phenomenon. On the other hand, during the service process, when the ambient temperature changes, due to the difference in thermal expansion coefficient between the components and the PCB board, thermal stress is generated in the solder joints. Periodic changes in the stress will cause fatigue damage to the solder joints and ultimately lead to fatigue. Invalidate.Since the driving power supply has such a great impact on LED street lights, how to solve the problem of easy damage of the LED driving power supply?In order to solve the problems of high failure rate and difficult maintenance of LED driving power supply, through the analysis of LED lighting principle and power demand, combined with the current actual application situation, we try to adopt low-voltage DC power supply mode in LED road lighting. DC power supply not only reduces the failure rate of LED drive power, but also reduces the safety risks of road lighting, and provides convenience for future electric vehicle charging.With the continuous development of light-emitting diode (LED) technology, LED lighting has gradually expanded from indoor to outdoor. The reason for the slow promotion of LED in the field of road lighting is the high power of road lighting and the harsh operating environment. After a period of tracking and testing of high-power LED street lamps, some LED lamps have failed one after another. Through the analysis of the failure, we found that the LED drive power supply damage accounted for as high as 90%. Although the theoretical service life of LED street lamps is as long as 50,000 hours (13.7 years), the service life of its driving circuit is relatively short, about 12,000 hours (3 years). Drive power has become a shortcoming restricting the service life of LED street lights. At the same time, due to the lack of uniform standards for LED drive power supplies that match the LED particles, the drive power output interfaces produced by various suppliers are not uniform, and the quality is uneven, which brings inconvenience to the maintenance of LED street lights, and the cost of replacing the drive power supply is high.The power supply problem has become an important factor affecting the promotion and application of LED lamps. Only by solving the problem of LED power supply can the application of LED lamps in road lighting be opened.1. The requirements of LED particles for power supplyIn order to solve the problem of LED power supply, we need to understand the basic working principle of LED particles and their power supply requirements.The LED lamps currently used in road lighting have an overall light-emitting structure, including two parts: an LED light source and a power source. The LED light source is a combination of a certain number of high-power LED particles (first in series and then in parallel) into a whole light-emitting chip. A single LED is actually a diode. When a certain forward voltage is applied across the diode to excite the P-N junction to conduct current, the LED can emit light. The nominal voltage of a single LED is 3.4V±0.2V (the actual working voltage is about 2.8~3.8V). Working current is related to power and brightness, and LEDs of different powers have different currents. Generally speaking, the higher the power, the higher the current, the more light will be emitted. The high-power 1W LED particles used in road lighting have a nominal current of 350mA.Through the structural analysis of the actual LED lamps, we can clearly see that a certain number of LED particles are connected in series to obtain an LED string with a working voltage of 40.8V±2.4V, and then these LED strings are connected in parallel to obtain one LED lamps with a working current of 3.5A. Calculating the loss, the lamp’s power requirement is 48V/3.5A.2. LED drive powerThe existing street lamp power supply line is 220V alternating current, and three steps of voltage reduction, rectification, and current stabilization must be carried out to provide a stable low-voltage DC power supply for LED lamps. First, the 220V AC power is stepped down into 48V low-voltage AC power, and then the low-voltage AC power is converted into low-voltage DC power by bridge rectification, and then converted into a constant current source by a high-efficiency switching regulator to provide constant current for the LED particles. Current.In order to reduce the chip failure rate, most manufacturers choose the combination of fewer strings and more parallel. The voltage requirements of existing LED lamps are mostly 48V. Each LED lamp may have slightly different power supply voltage and current requirements. In actual applications, it should be based on the overall Choose a suitable driving power for the voltage and curren
Generally speaking, when solar street lights leave the factory, the working hours are set according to customer requirements, but some customers will still ask whether the lighting time can be adjusted after installing solar street lights for a period of time. Customers want to extend or shorten the lighting time of solar street lights due to seasonal changes, which is very reasonable and achievable.The start and close time of the solar street light is determined by the street light controller. How to adjust the lighting time of led solar street lights also depends on the type of controller used. There are 2 basic ways to control the time of the solar street light controller:1. PIR controlThis kind of controller does not need to adjust the time, it will automatically sense the intensity of the light to control the light on and off. After installation, there is no need to adjust the light on and off time according to the season. It will automatically turn off during the day and turn on at night. This kind of light control is now widely used in lithium-ion solar street lights, and the cost is also low compared to several other control methods.Some customers will ask if the street lights will turn on automatically if it is cloudy. This needs to look at the cloudy effect. Under the common cloudy effect, it will not light up. It will only light up under extreme conditions. Of course, this kind of cloudy situation also needs to light up, and solar street lights are stronger than commercial LED street lights. The advantage is that it can also be illuminated in extreme weather, because the voltage is 12v for safe use of electricity, and it is not afraid of leakage.2. Time controlTime control is also one of the commonly used time control methods for solar street lights. It is to set the time in advance to turn on or off at a certain time. It is a bit more troublesome than light control. It needs to adjust the on and off time according to the season to avoid street lights. The situation that turns on and off in time. Now the more advanced time control controller can modify the time remotely.The special controller adjustment of solar road light is divided into manual adjustment and remote control adjustment. The external adjustment buttons can be adjusted manually. At present, most of the adjustments on the market are remote control. If this type of controller wants to adjust the working time, it must be equipped with a remote control.Solar street lights are now divided into split solar street lights and solar integrated lights. The split solar street light controller is generally placed in the light pole. Open the light pole protection cover to see the controller. The adjustment operation can be done by pressing the setting switch. It is not difficult. If there is no manual, try not to adjust it, so as not to damage the controller and cause the street light to not light up. The solar integrated light controllers are all in the lamp holder. If you want to adjust, you need to climb the pole or turn the pole down, turn on the lamp holder to adjust, you need to use a special tool to turn on the lamp, so if there is no remote remote control for the solar integrated lamp It cannot be adjusted. If necessary, please be sure to purchase a solar street light remote control for adjustment.
Bilbao , a Spanish city. Located in northern Spain, it is the original settlement of navigators in the Basque Country, famous for exporting iron ore and manufacturing ironware. The Port of Bilbao is the third largest port in the country after Barcelona and Valencia. The main terminal berths in the port area are as follows: GENERAL CARG0 (bulk cargo), BULK CARG0 (bulk cargo), 0IL QUAY (oil terminal), C0NTAINER (container) . Loading and unloading equipment includes various shore cranes, gantry cranes, portable cranes, container cranes, floating cranes, truck cranes and ro-ro facilities. With the rapid economic development, the port cargo throughput has increased at an average rate of 3.6% in the past ten years. In 2019, the coal throughput reached 4 million tons, the container throughput reached 506,000 TEU, and the total annual cargo throughput reached 45 million tons.Since 2018, China’s COSCO Group (COSCO) has made a strategic investment in the port of Bilbao in Spain and established a joint venture company CSP, determined to develop the port of Bilbao in Spain into our “Belt and Road” European strategy. Important node. Since then, various facilities of the port have been renovated. In October 2020, the CHZ lighting Spanish branch project team achieved good results after the port lighting renovation of QIL QUAY at the oil terminal port and won the high trust of customers. By 2021, in order to quickly emerge from the epidemic and revitalize the local economy, the local government has decided to increase support for local enterprises and stimulate investment. Therefore, CSP started the second phase of the port renovation project, this time the focus of the renovation is the CONTAINER (container) terminal.The engineering and technical team of CHZ Spain branch conducted an in-depth survey of the entire port, conducted in-depth research on every detail, and formulated a detailed transformation plan, using our FL21 and FL32 high-power floodlights. Both products adopt modular design and have good heat dissipation function. According to the height of the high pole lights in the port square, we have developed two ways to mix the lamps and lanterns, and use different beam angles to complement the far and near lights; finally, in order to ensure the safe use of the lamps, a conventional 100-240V conventional voltage is configured. And 180-528V high voltage drive, and matching 10KV lightning protection device to ensure safe use. FL21-450W FL32-750W (front) Beam angle After the joint efforts of the construction team, the lighting installation of one of the terminals was completed within 30 days, and the effect was very good. Previously installed a 2000W HID. In the previous installation position, we replaced FL21-450W and FL32-750W, which saves more than 60% of the energy. At the same time, the ground illumination has also been greatly improved, from the previous 150LX. Up to the current 230LX; the uniformity has also increased from the previous 0.25 to the current 0.43. From a distance, looking at the entire square of the pier, it looks so brilliant and dazzling.At the end of this stage of installation, the lighting effect won the praise of the port workers in Bilbao, and also won the high recognition of the port leadership; I hope that CHZ Lighting team will continue to work hard in the next projects and make excellent projects. CHZ team was also encouraged and decided to continue to dedicate good products in the next projects and make greater contributions to the construction of the port of Bilbao and the whole of Spain.
LED street lights are semiconductor lighting lights, which use light-emitting diodes as a light source. Because it is a solid-state cold light source, it has the characteristics of environmental protection, no pollution, low power consumption, high light efficiency, and long life. The difference between LED street lamps and conventional high-voltage nano-lamp street lamps is that the high-power LED street lamps adopt low-voltage DC power supply as their high source, and are high-efficiency white light diodes composed of GaN-based power blue LEDs and yellow phosphors. They are highly efficient, safe, energy-saving, and environmentally friendly. Long life, fast response speed, high color rendering index and other unique advantages, can be widely used in urban road lighting. The outer cover can be made of PC tube, high temperature resistance up to 135 degrees, low temperature resistance up to -45 degrees.High-power LED street lights refer to LED street lights with a power greater than 30 watts;Application places for high-power LED street lights: urban roads, sidewalks, squares, schools, parks, courtyards, residential areas, factories and other places that require outdoor lighting.Advantages of LED street lights:1. The light of the led street lamp is unidirectional, without diffusion, to ensure the light efficiency;2. The unique optical design of the led street lamp irradiates the light to the required area, improves the light efficiency, and achieves the purpose of energy saving3. The light color rendering of LED street lamps is much higher than that of incandescent lamps. The color rendering index of incandescent lamps is about 20, and the color rendering index of LED street lamps is above 80, which achieves the same brightness visually and psychologically. The illuminance of LED street lamps is on average higher than that of incandescent lamps. The lamp is reduced by more than 20%;4. LED street light has a low decay, less than 3% in one year, and it can still meet the lighting requirements for road use after ten years of use;5. The led street lamp has an automatic control energy-saving device, which can achieve the greatest possible reduction in power and save energy under different lighting conditions at different times;6. Long service life, providing 3-5 years of quality assurance;7. The quality is reliable, all components with high braking capacity are used, and each LED lamp bead has a separate overcurrent protection, so there is no need to worry about damage.LED street light technical indicatorsThe current standard of LED street lights is generally 0.48 for the average illuminance of the road surface illuminance uniformity, and the spot ratio is 1:2, which is in line with the road illuminance. In fact, the 1/2 center light class reaches 25LUX, the 1/4 center light intensity reaches 15LUX, the lowest light intensity at 16 meters away is 4LUX, and the overlapping light intensity is about 6LUX. At present, the street lamp lens material on the market is an improved optical material, with transmittance >=93%, temperature resistance -38—+90 degrees, and UV yellowing rate without change for 30,000 hours. It has very good application prospects in new urban lighting. The depth of the dimming, and the color and other characteristics will not change due to dimming. To develop LED street lightings, you should pay attention to the following aspects:★A. The improvement of luminous flux also needs to be further improved from the basic level of high-power LED epitaxial technology and chip technology.The method of making white LEDs at home and abroad is to first place the LED chip on the packaged substrate, bond it with gold wire, and then coat the YAG phosphor around the chip, and then encapsulate it with epoxy resin. The resin not only protects the chip but also functions as a condenser. The blue light emitted from the LED chip hits the surrounding phosphor layer and is scattered and reflected and absorbed many times, and finally emitted to the outside. The peak of the spectral line of the LED (blue) is at 465 nm, and the half-value width is 30 nm. Part of the blue light emitted by the LED excites the yellow YAG phosphor layer, causing it to emit yellow light (peak value is 555nm), part of the blue light is emitted directly or after reflection, and the light that finally reaches the outside is blue and yellow light, that is, white light. FlipChip technology (FlipChip) can get more effective light emission than traditional LED chip packaging technology. However, if a reflective layer is not added under the electrode of the light-emitting layer of the chip to reflect the wasted light energy, it will cause about 8% of light loss. Therefore, a reflective layer must be added to the bottom plate material. The light on the side of the chip must also be reflected by the mirror surface of the heat sink to increase the light output rate of the device. In addition, a layer of silicone material should be added between the sapphire substrate (Sapphire) of the flip chip and the bonding surface of the epoxy resin light guide to improve the refractive index of the light emitted by the chip. Through the improvement of optical packaging technology, the light extraction rate (luminous flux) of high-power LED devices can be greatly improved.★B. Optimizing the design of LED lighting equipment to improve the quality of use of LEDs. Therefore, it is particularly urgent to study the secondary optical light distribution design of high-power LED light sources to meet the light distribution needs of large-area projection and flood lighting. Through the secondary optical design technology, the design of additional reflecting cups, multiple optical lenses and aspheric light-emitting surface can improve the light extraction efficiency of the device. The traditional light source irradiation direction is 360°, the lamp relies on the reflector to reflect most of the light to a specific direction, only about 40% of the light reaches the road directly through the glass cover, and the other light is projected out of the lamp through the lamp reflector. , The efficiency of the reflector of the lamp is generally only 50%~60%, so about 60% of the light output is in the lamp, which is projected on the road after a loss of 30%~40%. A large part of the light output of the light source is limited to the internal heating and consumption of the lamp. Most of the light of the LED lamp is front light, which can achieve >95% luminous efficiency. This is one of the important characteristics of LEDs that distinguish it from other light sources. If this characteristic cannot be used well, the advantages of LEDs will be great. discount. Since most high-power LED lights are assembled with multiple LED chips, we need to illuminate so many light sources in different directions. We give full play to the characteristics of the chip's overall package and use lenses to solve it. Through optical design, it is equipped with different convex curves according to different needs. , Relying on the lens to distribute the light to different directions, to ensure that the large angle of light can reach 120°~160°, and the small one can concentrate the light within 30°. Once the lens is finalized, the same kind of lamps can be guaranteed under the premise of the production process. The light distribution characteristics of the two have reached the same level. It is completely possible to make LED street lights meet the batwing light type required by road lighting standards through repeated trials and continuous summing up of experience. Tunnel lights, street lights and general lighting have reached the lighting requirements of their respective application places.★C. Heat dissipation is a key problem that LED street lights need to solve.As we all know, LED is an optoelectronic device. During its working process, only 15% to 25% of the electrical energy is converted into light energy, and the rest of the electrical energy is almost converted into heat energy, which increases the temperature of the LED. In high-power LEDs, heat dissipation is a big problem. For example, if a 10W white LED has a photoelectric conversion efficiency of 20%, 8W of electrical energy is converted into heat. If no heat dissipation measures are taken, the core temperature of the high-power LED will rise rapidly, when its junction temperature (TJ) When the temperature rises above the maximum allowable temperature (usually 150°C), the high-power LED will be damaged due to overheating. Therefore, in the design of high-power LED lamps, the most important design work is heat dissipation design. Due to the high brightness requirements of LED street lights, the use environment is relatively harsh, if the heat dissipation is not solved well, it will quickly cause LED aging and decrease stability. A street lamp using 250W high pressure sodium lamp, due to mature technology and good heat dissipation control, even if it works for 5000 hours, the light decay is still very small. High-power LED street lights under the same conditions, if the heat dissipation is not solved well, the light decay will be great. The heat dissipation methods of LED street lights mainly include: natural convection heat dissipation, additional fan forced heat dissipation, heat pipe, loop heat pipe heat dissipation, and uniform temperature plate heat dissipation. The forced heat dissipation method of installing a fan has a complicated system and low reliability, and the heat dissipation method of heat pipe and uniform temperature plate is costly.★D. LED street lights will eventually choose modular installation and maintenance.The most high-pressure sodium lamps used on the road, the internal ballasts and other components are not easy to damage, most of the reason for not lighting is the damage of the light source, the maintenance method only needs to replace the light source. A skilled operator can perform high-level operations personally. However, LED street lights have many internal components. Except for the light source (chip), damage to other parts will cause the chip to not light up. Therefore, at the scene, it is impossible to immediately determine the cause of the damage to the LED street light. If the LED street light does not light up, the LED street light needs to be taken off and shipped back to the factory for various tests. This way of replacing LED street lights is very cumbersome. The final version of the development of LED street lights is to develop into modularity. The light source, electricity, etc. are all replaced in accordance with the plug-in connection, so that a skilled worker can fully independently judge the cause of the damage and perform on-site maintenance