Tag Archives: LED Street Light
Interpretation of how to use high-pressure LED to improve the efficiency of LED bulbs
Use LED as light bulbs to replace the threaded screw-in incandescent bulbs has many advantages. In general, we will trumpet (5-9) of the LED in series, using a power supply to line voltage into low voltage (typically a few tens of volts), when the current is about 350 to 700mA. In determining how best to allow users with the line voltage isolation, we need careful consideration, on balance. We can achieve power in isolation, can also be installed in the LED process in such isolation. In some low-power design, LED physical isolation is a common approach, because it allows the use of lower cost non-isolated power supply.
Figure 1 shows a typical LED light alternative. The example of the power supply non-isolated power supply, the means to achieve user isolation voltage protection is embedded in the package rather than the power supply. Obviously, the power of the space is extremely small, and thus pose a challenge to the package. In addition, the power to be buried inside the package, thus preventing the heat, affecting the efficiency.
Figure 2 shows a 120-volt AC power through the LED-powered, non-isolated circuit. It contains a power for the buck power stage rectifier bridge. The buck regulator is an "upside-down version", the power switch Q2 in the circuit, while the circulation diode D3 is connected to power. The power switch conduction period, through a source resistance of the current regulation. Despite this very high efficiency (80% -90%), but there are several limitations of this circuit efficiency shortcomings. Turn the power switch must carry the full output current, while the power switch is off, the output current flows through the circulation diode. In addition, the current sense resistor R8 and R10 of the voltage of about 1 volt. 15 to 30 volts compared to the LED voltage drop across all three are great, and power efficiency will be a constraint. More importantly, these losses will promote bulb temperature. Ability of the LED light will gradually decrease, and this ability with the LED operating temperature are closely related. For example, 70oC conditions, LED light output by 30% of the time exceeded 50,000 hours, and in 80oC conditions, this time only 30,000 hours. As the bulbs are installed in some of the "tube" in which "tube" tend to impede the heat is not conducive to convection cooling, the heat problem is further complicated.
LED manufacturer LED series by the number of teams in a common substrate, to create a higher voltage of the light. The high pressure also brought light or have a lower cost or higher power supply efficiency. Using these high-pressure products, we only need to use a rectifier and a ballast resistor, in order to achieve more cost-effective power method. Although this power can produce very good power factor, but is inefficient because a large part of the input voltage are used in a steady flow resistor, resulting in 30% -50% of the LED power loss. However, it can be used for small volume, low-power applications. However, in some high-power applications, the low efficiency allowed to no avail. Figure 3 shows another alternative: the use of a boost power supply. Most of the circuit the same way as above. However, the switch, diode, and current detection loss is much smaller, bring up to 90% to 95% efficiency. In addition, the circuit also has a good power factor of 97%.
Figure 4 is described in Figure 1-2 Schematic diagram of the power of pictures. Even if the power output generated roughly the same, but there are some significant differences in size affect the power supply. Power boost inductor size was smaller, because of its lower storage requirements. Compared to the step-up power supply, power supply with a larger step-down resistor. The simulation of the load resistor as a resistor (Figure 2 R20), used to determine when to turn dimmer silicon controlled rectifier (SCR). Need to do this because of the dimmer switch in the Triac next to a component of electromagnetic interference (EMI) suppression capacitor, in the case of no-load power supply voltage is relatively higher. This will disrupt the power supply, leading to instability dimming. Shique not necessary to use the power boost, because the LED through the boost inductor connected to the input, to provide sufficient load, so the problem will not be a problem. Not shown in the back of the board, but as shown in the diagram, there are more low step-down power supply circuit. Therefore, the step-up power with lower power consumption, this LED bulb replacement, such as limited space applications is extremely important.
In short, because of its low power consumption, high-voltage LED, a small temperature rise characteristics, can help increase the spin-LED lamp life. It is through the use of alternative buck-boost power supply, thereby enhancing the power efficiency to achieve. Boost the power loss is about half the buck regulator. In addition, fewer components boost power, power factor better, smaller, and the use of a triac dimmer switch assembly is easier to achieve.
polarized LED development path
Low-carbon energy is now the trend of society, in the National Development and Reform Commission and other departments slowly released by the size of the power out of the context of the roadmap incandescent, LED lighting for granted as an investment hot spot in the hot, large and small brands and factories everywhere in the country there, local governments are vying to dedicate resources to the LED lighting industry as a pillar industry for support.
December 2, 2011, ZHAGA DEKRA testing and certification organization in Shenzhen, jointly held a "ZHAGA standardized light engine interface design research and discussion will be" at the same time it is also a member of China held its first panel discussion of the standardization work. This is to facilitate the interface between the LED light engine compatible and replacement; and ZHAGA will launch CONFORMITY ASSESSMENT Conformity Assessment certification to promote the application of the market. Speakers of the conference total from ZHAGA General Mr. Menno Treffers and DEKRA certification manager and the company s chief product manager, but also the International Electrotechnical Commission standard system and IECEE CB Testing Laboratory Commission, the expert group meeting convened special , European certification system (CCA & ENEC) Technical Services Section of the Vice President Mr. Ted Gaertner.
The meeting attracted a large number of Greater China s leading manufacturers of many industry participants to come, companies addresses mainly in Shanghai, Fujian, Taiwan, Hong Kong, Shenzhen, Dongguan, Zhongshan and other famous enterprises, some of the best manufacturers as follows: Philips Philips, Osram, on yaming, Xiamen Rieter letter, Cree Cree, the ground on the Kingsun, BYD BYD, etc., but also attract retailers and other buyers to come to IKEA IKEA participants.
This standardization will help to contain LED light engines are not compatible with market differentiation, so that consumers can rest assured that the selection and purchase market with LED products can be replaced, and can continue to enjoy the LED technology offers performance upgrades and services. In addition, industry development, Zhaga prompted the establishment of standards of innovative LED lighting applications, and increase market competitiveness.
On the surface, LED lighting industry, such as tea fire, but hidden behind the prosperity, also will gradually emerge. Now the LED industry can be said to be princes melee, different LED manufacturers with their own understanding of a wide variety of product release, it was more a joke: the LED lights now, is really a thousand eyes of 1000 Hamlet ah! Is due to different manufacturers are not compatible with the product can not be replaced; to promote LED lighting products and parts replacement on the market more difficult, it also makes consumers feel no way to adapt and even at arm s length; so as to increase the difficulty of LED applications, weakening the market competitiveness.
How to break the impasse, the road was in the end where? Some people waiting for government support, some are thinking, but the industry giants have to act. In 2010, including Philips, Osram, General Electric, Panasonic, Cree CREE lighting industry giants, including a number initiated the establishment of an industry standards organization – Zhaga Alliance (ZHAGA Consortium), mainly refers to the unified interface specification LED light engine design standards. To cope with the ongoing development of LED technology, by defining a variety of special LED light engine interface data, Zhaga standard engine cover various properties of light, consists mainly of physical size, luminosity, electrical and thermal performance, etc., but finally reached Zhaga Lianmeng between products of different manufacturers interchangeable and compatible. Now, there are 162 countries in the world s leading manufacturers – has come from European companies, U.S. companies and Asian companies to join Zhaga, more world-renowned testing and certification body DEKRA European standardization working groups involved in ZHAGA formulation.
As a manufacturer, in fact, my heart has indescribable pain. Every now launched a new product, manufacturers have to put in a lot of manpower and resources to design a new program, so the cost can not high? This is the issue of industry representatives sigh! More worrying, because the interface is not standardized products, the products of different manufacturers stringent than more difficult. Between the manufacturers is not in the product life, color temperature, cost and other aspects of competition, but play the "price war." Can not make large-scale production is difficult to reduce the cost of LED lighting products; to blindly reduce product prices, product quality is difficult to avoid is not guaranteed.
Was chosen as the conference organizers DERKA because DEKRA testing and certification of LED lighting pioneer in the field. Not long ago, DEKRA performance with unique LED sign, received the prestigious European Electronics Technology (ETOP) Innovation Award results. DEKRA LED sign is devoted to the performance which need to meet more stringent safety and performance requirements to the product and the idea of ??certification marks; its purpose is to better distinguish between the quality of high-quality LED light bulbs, lamps and general performance of the lamp; in high-quality manufacturers to accelerate the application of LED lights, while the market; also carbon emission reduction, energy conservation and the environment for consumers to make their own step.