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Yaorong manufacturers teach you how to choose LED solar street lights correctly

2021-08-1719

Yaorong manufacturers teach you how to choose LED solar street lights correctly



For urban lighting, traditional lighting equipment consumes a lot of energy, and there is a huge waste of energy. Solar led street lights can reduce lighting power consumption and are the most important way to save energy.


Solar street lights rely on technical advantages to use solar panels to convert heat energy into electrical energy for use in lighting, breaking the limitation of traditional street lights using city electricity, and realizing self-sufficient lighting in cities and villages, and solves the problem. The problem of high electricity consumption and high electricity bills.


With the acceleration of my country's urbanization process and the acceleration of urban infrastructure construction, as well as the country's emphasis on the development and construction of new cities, the market demand for solar led street light products is gradually expanding.


At present, there are more and more manufacturers of solar street lights, and the market is mixed. How to choose solar led street lights and how to distinguish between them?


 It can be selected from the following 4 aspects:


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1) Solar panels: commonly used solar panels are monocrystalline silicon and polycrystalline silicon. Generally speaking, the conversion rate of polycrystalline silicon is usually 14%-19%, while the conversion rate of monocrystalline silicon can reach 19%. -twenty three%.


2) Battery: A good solar street lamp must ensure sufficient lighting time and brightness. If this is achieved, the battery requirements are naturally high. At present, solar street lights are generally lithium batteries.


3) Controller: There are two kinds of controllers: PWM and MPPT, which can reduce the overall brightness and save energy during the time when cars are scarce. By setting reasonable power at different time periods, the lighting time and battery life are prolonged.


4) Light source: The quality of the LED solar street light source will directly affect the use effect of the solar street light. Ordinary LEDs have always had heat dissipation problems, and the light efficiency is low, the light decay is relatively fast, and the life of the light source is very short.


Yaorong Technology uses high-efficiency monocrystalline silicon solar panels with a photoelectric conversion rate of 20% and a long life.


Battery: Lithium iron phosphate battery, which can be deep cycled up to 2000 times, is safe and reliable, will not catch fire or explode.


Intelligent controller: with intelligent control of lighting time, overcharge, overdischarge, electronic short circuit, overload protection, anti-reverse connection protection and other functions, can adapt to cold, high temperature, humidity and other environments.


Light source: 3030 lamp beads, high-intensity imported PC optical lens, bat-wing light distribution, realizing uniform light distribution and greatly improving the lighting effect


The all-in-one machine contains heat dissipation profiles, lithium iron phosphate batteries, solar TV boards, visual control systems, installation sleeves and other components. Lithium iron phosphate battery is high-efficiency, light and convenient, and has a long life. It inhibits the polarization of the battery, reduces the thermal effect, and improves the rate performance. The heat dissipation profile has excellent thermal conductivity, and the heat exchange area is large, which is conducive to speeding up the heat exchange and taking away more heat, so as to achieve the ideal heat dissipation effect.


In the design of actual road lighting fixtures, you can use a spherical universal joint to fix each LED on the fixture under the premise of basically setting the projection direction of each LED. When the fixture is used for different heights and illumination widths At the same time, the spherical universal joint can be adjusted so that the illumination direction of each LED can achieve a satisfactory result. When determining the power and beam output angle of each LED, according to E(lx)=I(cd)/D(m)2 (light intensity and illuminance distance inverse square law), the basic The power that should be available when selecting the beam output angle, and the light output of each LED can reach the expected value by adjusting the power of each LED and the different power output from the LED drive circuit to each LED. These adjustment methods are unique to road lamps that use LED solar street light sources. Making full use of these characteristics can reduce the lighting power density under the premise of meeting the road surface illuminance and uniformity of illuminance, and achieve the purpose of energy saving and environmental protection.


1. Design of heat dissipation and protection structure:


According to the equivalent relationship between luminous flux (lumens) and radiant flux (watts), 1W radiant flux can produce 683 lm luminous flux in the most ideal case (black body radiation). Even if the luminous efficiency of the LED is continuously improving (it has reached more than 120 lm/W), it cannot convert all the energy into light energy output, and the rest is converted into heat energy. In the long run, the heat dissipation problem of LED lamps will be a long-standing problem. The heat dissipation of LED solar street lights is one of the key problems that need to be solved. It is not only directly related to the luminous efficiency of the LED when it is actually working, but also because of the high brightness and heat generation of LED solar street lights, and the outdoor use environment is more demanding. Poor heat dissipation will directly lead to rapid aging of the LED, and the stability will be reduced. Road lamps used outdoors should also have a certain level of dust and water resistance (IP),


Good IP protection often hinders the heat dissipation of the LED. Solving the two contradictory problems that have to be solved is one of the most important aspects that should be paid attention to when designing road lamps.


In most road lighting applications in my country, the amount of flying dust in the air is relatively large, sometimes reaching a large amount (such as sandstorms). This type of lighting is used for a period of time under normal conditions (about three months to Half a year), the gap of the internal radiator will be filled with dust, which greatly reduces the effect of the radiator. In the end, the service life of the LED is significantly shortened due to the excessively high operating temperature.


To take into account the heat dissipation and IP protection of LEDs in road lamps, a more reasonable design concept is:


a. In the critical heat dissipation position, a heat conducting plate should be used. The heat-conducting plate is inside the metal plate. There are thin pipes for the flow of refrigerant evenly distributed, and the thin pipes are filled with refrigerant. When a certain part of the heat-conducting plate is heated, the refrigerant in the thin pipes will flow quickly. Make the heat conduct quickly. The thermal conductivity of a good heat-conducting plate can reach 8-12 times that of a copper plate with the same thickness. Although the price is higher, if it is used in key parts, the heat dissipation of the LED will be more effective.


b. Design the shell of the lamp into a heat-dissipating device shape. At present, most road lamp housings are made of aluminum. The direct use of the outside of the lamp housing as a radiator can not only ensure the requirements of the IP protection level, but also obtain a large heat dissipation area. The radiator composed of the lamp housing can be dusty. , Can be washed by natural wind and rain, so as to ensure the continuous effectiveness of the radiator.


2. Optical design of secondary light distribution


Secondary optical design is an important technology that determines the light distribution curve, output light efficiency, uniformity, and glare index of LED street lights. In terms of secondary optical design, the radiation forms of LEDs include Lambertian, side-fired, bat-wing and concentrating types. In the field of road lighting, Lambertian type and bat wing type are more suitable based on design experience. Through the design of secondary optics, the illumination range and luminosity curve of LED are in line with the needs of road lighting.


At present, the most common form of use of LEDs in road lamps is mainly in the lamps. A matrix LED is installed on a flat mounting surface (also a reflective surface). This design method is impossible to get a good result. Luminaires with light distribution.


The biggest feature of lighting LEDs is that they have the function of directional light emission, because most of the current power LEDs are equipped with reflectors, and the efficiency of such reflectors is significantly higher than that of lamps. In addition, the efficiency of the self-reflector is already included in the detection of the light efficiency of the LED. Road lamps using LEDs should make use of the directional emission characteristics of LEDs as much as possible, so that each LED in the road lamps can directly emit light to various areas of the illuminated road surface, and then use the auxiliary light distribution of the lamp reflector to Realize a very reasonable comprehensive light distribution of road lamps.


3. Constant current drive circuit design


The power system of LED street lights is also different from traditional light sources. The constant current drive power required by LEDs is a cornerstone to ensure that they can work normally. Simple switching power solutions often cause damage to LED devices. How to make a group of tightly compressed LEDs work safely and reliably is also an important indicator for investigating LED street lights.


The requirement of the LED for the drive circuit is to ensure the characteristics of constant current output. Because the junction voltage is relatively small when the LED is working in the forward direction, the constant LED drive current is guaranteed, which basically guarantees the constant output power of the LED. For the current situation that the power supply voltage supply in our country is not very stable, it is very necessary for the driving circuit of the road lamp LED to have a constant current output characteristic, which can ensure a constant light output and prevent the LED from overpowering.


In order to make the LED drive circuit exhibit constant current characteristics, looking inward from the output end of the drive circuit, its output internal impedance must be very high. When working, the load current also passes through this output internal impedance. If the drive circuit is composed of a step-down and rectifier filter plus a DC constant current source circuit or a general switching power supply plus a resistor circuit, it must also consume a lot of money. Active power, so these two types of drive circuits basically meet the premise of constant current output, and the efficiency is impossible to be high. The correct design scheme is to use active electronic switching circuits and high-frequency currents to drive the LEDs. Using the above two schemes can make the drive circuit have high conversion efficiency while maintaining good constant current output characteristics. .


To sum up the discussion: Whether LED solar street lights can truly achieve the advantages of energy saving, environmental protection and long life in practical applications, the key is to solve the three aspects of heat dissipation and protection structure design, constant current drive circuit design and secondary light distribution optical design.


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