月份：2012年5月

wired led bulb used for LED Street Lights

 

LED lighting is recognized as the next generation of green and low power consumption lighting technology. Single view from the luminous efficiency, LED light now has to reach and exceed the level of conventional light sources, but due to the expensive cost, they are still blocked in the popularity of LED lighting. As far as I think, wired led bulb cost problem is from the LED heat sink.

wired led bulb used for LED Street Lights

Street lights, long working hours, is considered to be the first choice for LED lighting applications. After the Chinese Government’s actively promoting, the total number of applications of LED street light in China now is leading the world. But the light fades, black lamp failure is widespread, and several hundred million RMB boondoggle. The cruel results of LED street (wired led bulb) show that: LED light source and power dissipation are still the problems which is not resolved. As we all know, LED cooling temperature and power are not very high, belonging to the room temperature heat transfer, heat transfer and talk, the LED heat dissipation is not complicated, involving only a very small part of the heat transfer. The thermal conductivity of heat transfer can use off-the-shelf heat transfer calculation software, a very accurate solution.
Leading to simple LED heat problem is complicated, has not been solved: the knowledge gaps, with the rich heat transfer of knowledge and proven technology personnel. To participate in the study of LED heat (wired led bulb) poorly,  it will cause hundreds of years of human mature transfer knowledge and technology is not introduced into the field of LED heat. Popular in the electronics cooling industry, active cooling, passive cooling, there is no such
terminology in the heat transfer. Only in respect of these terms, we can conclude: in the LED High Bay industry within today’s popular “Heat Transfer” (electronic cooling industry) does not originate from nearly a hundred years old, very mature of heat transfer, but start all over again, by a non- heat transfer to build.

This fundamental basic knowledge of heat transfer is a very important concept, not to be, a focus on industry in general.
This article will focus on heat transfer, cooling to analyze the progress of LED street tragic reasons for the technical level.

 

Properties of LED replacement tubes

Commonly used LED replacement tubes are T8 LED tubes and T10 LED tubes. They are new lighting technologies. However, compare with traditional fluorescent tubes, what are the advantages of LED tubes?

 

LED replacement tubes are the best energy-saving tubes presently. T8 LED tubes with power consumption of 15W can replace 40W-80W traditional fluorescent tubes, and can save more than 60% energy. They have been widely used for commercial purpose and residential purpose.

 

Commonly used LED replacement tubes are T8 LED tubes and T10 LED tubes. They are new lighting technologies. However, compare with traditional fluorescent tubes, what are the advantages of LED tubes?

 

More comfortable: Due to the ultraviolet rays sent out by fluorescent tubes, mosquitoes are usually attracted and gathered around them. Most of them even entered the internal of tubes and died there, leaving countless dark spots and reducing the brightness of tubes. However, LED replacement tubes can eliminate such annoy problem. There is no ultraviolet ray generated by LED lamps. Customers used LED tubes do not have to worry about mosquitoes.

 

Small light attenuation factor: LED tubes applied the most sophisticated manufacturing technique, use SMD 3528 LED chips. The light attenuation factor has been reduced into a lowest level. The average light attenuation after 5000 hours is only 8%. The average light attenuation after 30000 hours is around 30%.

 

Easier installation and maintenance: there is no need to change circuits, no need to modify ballasts, no need to change covers. They only thing that customers need to do is to remove the starter. LED tubes are much quieter than fluorescent tubes. They emit much less harmonic waves, the best lighting device in places where sophisticated electronic equipments are used.

 

Higher conversion efficiency: traditional lamps are always overheated. They generated a lot amount of heat during their work. Because they have a very low conversion (from electric energy to optical energy) efficiency. LED replacement tubes can convert more than 80% electric energy into optical energy, dramatically reduced the waste of energy.

Soft LED Street Light, good for your eyes: traditional tubes work under AC, thus will generate flickers with a frequency of 100-120Hz. Since the frequency exceeds our sense function, these flickers cannot be seen by us, but are actually harmful for our eyes. LED tubes work under DC, there is no flicker phenomenon. This kind of tubes can be in classrooms, libraries, in where students need to spend a lot of time on reading and writing. These tubes can protect their eyes and reduce the risk of myopic eyes.

Chinese LED manufacturers contend in Japanese LED lighting market (2)

Watanabe Yasushi from Japan JET Lighting Department has a different point of view. “After the earthquake happened in March last year, more and more Chinese products swarmed into Japanese market. Within several sampling inspections, we found that many Chinese LED bulbs cannot work as long as 50000 hours as marked. Most of them had the same problems: power suppliers and overheat.” Watanabe Yasushi indicated that more than 50% LED products from China is unqualified due to their unfamiliar with Japanese LED lighting standard.

 

Watanabe Yasushi from Japan JET Lighting Department has a different point of view. “After the earthquake happened in March last year, more and more Chinese products swarmed into Japanese market.

 

At the same time, Chinese LED manufacturers suffered fierce competitions from local LED manufacturers. Panasonic, the largest lighting enterprise in Japan, decided to promote a restructuring plan: combined Panasonic Lighting (a sub-company of Panasonic) with its Lighting Department together as a giant Lighting Business Group. Panasonic indicated that, after this reconstruction, the annual sales of 2012 are expected to reach up to 35 billion yen. The annual sales of 2015 can reach up to 100 billion yen. In which LED products will occupied more than 40% of Japanese local lighting market.

 

Meanwhile, another local brand Toshiba is stepping up the penetration in Japanese LED bulb market. Sato Koji, director of LED Business Department of Toshiba indicated that the increase of LED month sales is significant in 2011, from 2.8 million in June to 4.8 million in December. The annual growth is over 300%.

 

Competitions from local brand brought huge pressure to Chinese LED manufacturers. “Japanese have the traditional channels for sales. But it is very difficult for Chinese manufacturers to get into. Even for ordinary LED lights, we can only import our products though an exclusive agency set in Japan firstly, then transfer them into traditional channels. We are planning to be the OEM for Japanese local LED brands, this is another way to enter Japanese lighting market.” said Jiawei Pang, general manager from Tong Pu technologies Co,. Ltd.

 

General manager Mr Xiao from Shengzhen Juzuo Industrial Co., Ltd. has studied Japanese market for many years. According to his words, it is impractical for Chinese LED High Bay products promiscuously enter Japanese market. “Our manufacturers need to do sufficient research before entering Japanese market, choose several flagship products according to the specific conditions of it.”

Chinese LED manufacturers contend in Japanese LED lighting market (1)

In recent years, more and more Chinese LED manufacturers entered into Japanese LED lighting market by the way of strategic co-operation. Nichia, Sharp, Toyoda Gosei, Showa Denko KK, etc. Many Japanese chip manufacturers co-operated with Chinese enterprises or expressed willingness to co-operate with Chinese enterprises.

 

In recent years, more and more Chinese LED manufacturers entered into Japanese LED lighting market by the way of strategic co-operation.

 

LED enjoyed a rapid development in Japan in past few years. According to Japanese local statistics, annual sale of LED bulbs within Japan is more than 31 million, 40% higher than last year. In addition, many appliance stores in Japan began to set their own LED special counter for customers. The high demand of LED products in Japanese market makes themselves become the “hot cake” for foreign LED enterprises. Chinese LED manufacturers have seen Japanese LED marketing as the main development target.

 

Those who are prepared to enter this “overseas battle field” indicated that LED patent is a threshold and the standard is a pass. “If we want to enter Japanese LED lighting market, we have to overcome these two difficulties. It is very hard for medium and small-sized LED companies” Said Chen Zheng, CEO of Shenzheng Dingxi lighting technologies Co., Ltd. However, those who have already entered the Japanese LED lighting market complained that they start flimsy. “The present situation is not as good as we though. We suffered a lot of fierce competitions from local LED Projects companies. Meanwhile, we have to face with restrictions from patents.” Said one officer of Shenzhen Mason Technologies Co., Ltd.

 

At the same time, entering Japanese LED market is more and more difficult for Chinese LED manufacturers. “It seems that they don’t want to share this cake with us. The requirements for entering this market is much more strict than last year” Said Chen Zheng. Recently, Japanese Economy, Trade and Industry Department announced a new regulation (will be executed in 1st July, 2012) for foreign LED manufacturers: only those LED products which owned EPS certificate can be imported into Japan. EPS certification has very strict requests not only for product quality and production tests, but also for their factories’ equipments and management. Most LED manufacturers can pass though EPS certificate in their products but fail in their factories’ examination.

Japanese lighting manufacturers quietly lift the led production lights capacity of a price war competition

LED production lights capacity competition is oversupply concerns in 2011, Taiwan plant with large international companies competition will be intense. Global LED industry will enter the forces of growth and decline of the transition period.

With the Japan LED lighting industry raising of price competition, usher LED lighting into the take-off year.  South Korea, mainland industry are also menacing, driving regional industrial competition, and promoting Taiwan LED enterprises accelerate lighting applications layout.

Japanese lighting manufacturers quietly lift the led production lights capacity of a price war competition

With the intensity of Market price competition, under the usher of Japan government, including Toshiba, Panasonic and  first-tier manufacturers such as LED bulbs 50/50 cut, Taiwan-based LED industry estimates that with the trend of cost deduction，LED bulbs prices will steadily go down in 2011,  Large-size LCD backlight and LED lighting as a twin-engine in 2011 growth momentum. The LED industry estimates that LED lighting penetration is about 3% compared with 2010, , the 2011 led production lights penetration rate is expected to reach 6 to 10 percent.

We can guess South Korea LED Street Light output will continue to grow with the next two years,  and LED packaging market share is expected to increase to 24-25%. Taiwan LED packaging market share will be in the same position. Compared with the various regions of the world and the module output, Japanese manufacturers market share is about 31%, top to the first grade, while Taiwan and South Korea were up to 2 percent, European and the United States each accounted for about 10%. Among them, South Korea industry market share in 2009 is only about 10%, but it quickly jump to 20 percent within one year. It kept pace with led production lights industry.

Due to the capacity utilization is still low in Korean LED plant, a marked slowdown in the expansion progress from the secondhalf year in 2010. But the Taiwan plant is benefit from the huge demand for TV backlighting in Korea Factory and upgrade to Taiwan LED purchase amount, which promote the growth of LED production capacity. However, mainland China LED High Bay industry is hard to catch up. The upstream MOCVD machine units may be open out a large number in the second half of 2011. The LED production lights industry worries that once South Korea LED plant technology enhanced, mainland industry production capacity can also be heavy growth. 2011 terrorist will set off oversupply of capacity competition, LED marketing will enter price competition. The price declined in fear of more than 30%. Regional industrial competition is heating up.

Advantages of LED lighting source

LED lighting market is strengthened continuously. traditional lights have been replaced regularly by various LED lighting products. In the next section, we are going to give out several advantages of LED lamps that bring them to a leading position in lighting market.

 

LED lighting market is strengthened continuously. traditional lights have been replaced regularly by various LED lighting products.

 

Higher energy saving: LED lighting source uses DC diver. Single component’s power consumption is just 0.03W-0.06W. The electrical to optical conversion efficiency can approximately be up to 100%. LED lamps can sever more than 80% energy compare with traditional lamps with the same luminous flux.

 

Longer working life: some people name LED lamps as ever lighting lamps. Of course, it is an exaggerated metaphor. But LED lamps do have much longer life than traditional lamps (theoretically, more than 50000 hours). LED lamps use solid lighting source, packaged by epoxy resin. The entire lamp body tightly encapsulated, with no gap.

 

Multi-color: LED lighting source can utilize the various combinations of three primary colors (red/blue/green) to create multiple colors. Currently, only 16 types of colors can be sent out by LED lamps. However, this part of LED technique still need to be developed. Technicians believe that, in near future, LED lighting source can emit 256 real colors with the help of computers.

 

More environmental friendly: There are no ultraviolet rays (radiation) and infrared rays (heat) in LED lights. Every part of LED lamps can be recycled. There are no pollutants and toxic chemicals. LED lamps use solid lighting sources, can be touched, no human-hazard substances.

 

More sophisticated: compare with traditional lights, LED lighting source is a kind of low voltage microelectronic devices, successfully combined computer science, telecommunication technology, image processing, embedded control system, etc. Thus, it is a digital product, and also a semiconductor optoelectronic device. LED lighting technology has properties of online programming, infinite update and flexibility.

 

With the rapid development of LED lighting industry, its occupation of lighting market will continuously increased in next few years. Also with the enhancement of people’s environmental awareness, countries all over the world start to execute all kinds of environment protection plans. LED lamp is the first step for our green life. A further development is expected. Finally, LED lamps will completely take place of traditional lamps, becoming the mainstream lighting products.

LED lighting broad: in cascade or in parallel?

 

LED lighting broad are typically used in LED panels and in some cases LED street lights. There are connection ways for LEDs: in cascade and in parallel. In practice, the most likely used ways are all kinds of combinations of cascade circuits and parallel circuits, determined by the specific requirements of input/output voltage, power factor, etc.

 

LED lighting broad are typically used in LED panels and in some cases LED street lights. There are connection ways for LEDs: in cascade and in parallel.

 

 

 

In what way should LEDs be connected? In cascade or in parallel? Which connection is more suitable for LED lighting broad work with a wide range (AC85V-265V)? At present, most LED power suppliers are none-isolated. The output of wide range voltage should not larger than 72V. In other words, the maximum number of cascaded LED chips is 23. Also, number of LEDs in parallel is limited, normally 6 group/8 group/12 group. If we connect too many LEDs in parallel, the working current (240mA in total) will exceed the threshold level and lead to an excess temperature, causing damages to LED Street Light.

 

 

Relations of LED series-parallel connection with PFC power factor:

The current LED power suppliers in the market have three different types of PFC: 1. Power suppliers without any specialized PFC circuits, PFC of which is around 0.65; 2. Power suppliers with passive PFC circuits, PFC of which is around 0.92; 3. Power suppliers with active 7527/6561 PFC circuits, PFC of which is about 0.99. If fact, the power factor of solution 2 is just a little bit lower than that of solution 3, but cost much less than it. LED High Bay manufacturers are more willing to design power suppliers with passive PFC circuits rather than active PFC circuits. Passive PFC circuit, also known as valley fill PFC circuit, has a working voltage half of the peak of the input voltage (AC). For example, if the input voltage has an average value of 180V, the peak value should be: 180 x 1.414 = 254V, half of it is 127V, subtract this value by 30V (voltage difference of the step-down supplier), then we have the maximum output voltage: 90V. That means the maximum cascaded LED chips is 28. Thus if we want to have a higher power factor, we cannot connect too many chips in series in the LED lighting broad. Otherwise, the low voltage cannot be reached.

 

 


British towns staged a “midnight lights-off projects” to pursue led spotlights dimmable

“Midnight lights-off method” is swing in the all England rural, suburban and downtown street. Although some residents and police are worried about that it will increase the number of traffic accidents and crime. On the survey of 133 local goverment, 98 people said they are reducing the lighting of G24 LED Light, and some are intented to do so.

The county or even councial who participated in the survey, as well as several major cities, show that they are reducing the LED Tunnel Lighting or have this intention. Including Cardiff, Sheffield, Edinburgh and London in some areas.

On the contrary, Most small councils have no such plan. Some of which are only responsible for the lighting of the outside road region, such as parks, parking lots, and sidewalks.

Reducing street lighting projects includes cutting down some lighting, and installing new lights which can let led spotlights dimmable or close at the mid-lights such as LED Street Light. In some projects, we can through the new device to let processor make the lights dimmer or brighter.

A British parliament claimed that “Midnight lights-off method” can not only save electric charge, but also energy saving. The 7500 thousand street lights on British spent 5 million pounds annual year.

Right now,  Norfolk is currently being implemented one of the largest programs. Norfolk’s 3300 streets and rural areas will be taken to “Midnight lights-off ” starting from midnight to 5:00 to turn off the lighting system.

In addition, the main traffic lines will install more than 5000 led spotlights dimmable lights. The illumination intensity is reduced by 1/3, from 20:00 to 5:00.

The British Conservative Party Council said, the move can save £ 167,000 every year, but the Norwich Green Party MP Steven Altman citilized such projects.

He said: “The environmental and economic benefits of this program has been exaggerated. A lot of residents are worried that this approach will bring increased crime, and  expressed their opposition.

South Korea to promote high efficiency led lighting,fusion technology development $270 million of LED industry

The South Korean government announced in 2015, will invest 3,000 billion Korean won (about $ 279 million) to support the research and development of light-emitting diode (LED Lights). Korea Ministry of Knowledge Economy said in a meeting of economic policy adjustment. In order to push the high efficiency led lighting integration and technology development of the LED, the budget support of the total amount of 3,000 billion Korean won will be allocated  in the next five years, and to prepare ,and prepare promotion the LED industry to leap forward support strategy.

Known to promote the  original core technology development and popularization of LED High Bay lighting in public institutions by the Ministry of focus investment
in the early 2009. A new policy is focused on how to merge the LED technology with existing industries innovatively such as lighting, medical, and other integration and create a more high value-added technology.

The South Korean government put forward that ensure the new market-driven competitiveness and the market creation and consumer reliability, constitute the three major policy task in a industrial ecology of virtuous cycle, the plan to promote high efficiency led lighting integration career to the world’s advanced position before 2015.

Knowledge Economy Ministry combine the LED with IT first, will ensure lighting system that is  by individual or central control energy conservation , with tailored lighting of users
psychologically and physically , sterilization and purification function lighting etc new markets competitiveness.

The South Korean government invest 3,000 billion won within 5 years.Separated from the original blue LED,from the diversification of the particular wavelength or full color products , and preparations for the activated LED Plant Factory, the intelligent car headlamp innovative LED industrial base of integration.The South Korean government is also planning to implement rules marked of lighting functions and system of Management evaluation results etc in 2011.

Convenient for consumers to identify products. Also induce a large, small and medium enterprises to strengthen cooperation , also plan to manage high efficiency led lighting Forum in 2011 and provide of the LED Experience Exhibition of  technical exchanges between enterprises ,so that can reduce the cost burden of SMEs in the LED lighting certification, structure for a virtuous cycle of industrial ecology   .

South Korean government will organize a organization that the tentative name is LED policy agreement ” to help Smooth cooperation of enterprises and develop LED fusion technology . Additionally plan to let 70% building of Sejong City adopt LED lighting. Make the Sejong City mold into the LED Street Lights city ,to invest 10 billion won (about $ 9.29 million )  in 2011 , 60% ​and scope lighting of the river, 16 reservoirs will be replaced of high efficiency led lighting .

Industry policy officials of Information and Communication Ministry, the Liu Xiugen said that if integrate the force of the government and industry ,in the market of LED lighting and the integration markets formally opened within 1 to 2 years  , Korea will be able to ensure the dominant position .

Tasters of LED current

Why constant current is required?

Lighting Emitting Diodes need to work in strict working conditions. This is determined by their properties. LED Lights are vulnerable to temperature change. LED voltage will be changed along with temperature, consequently leading to the change of LED current. As we all know, each LED has a particular working current. Long-term working in a current larger than the working current will cause damages to LEDs, even destroy them. Here constant current means LED current will remain a constant value when external conditions change, like the increase of temperature and LED voltage. However, maintaining a constant current is not an easy job.

 

Lighting Emitting Diodes need to work in strict working conditions. This is determined by their properties. LEDs are vulnerable to temperature change.

 

How LED power suppliers match with LED light broad?

Some customers prefer to buy LED light broads at first, then look for power suppliers. It is very hard for them to find suitable suppliers (either with an excessive current and an insufficient voltage, like I>350mA,V<40V or with an insufficient current and an excessive voltage, like I<40mA,V>180V). This mismatching between LED High Bay Light broads and LED power suppliers will cause excessive working temperatures, low light efficiencies, or insufficient input voltages. The best way is to choose LED components from one LED manufacturer. Generally, LED light broads and LED power suppliers from one manufacturer are well matched. LED chips will be installed onto the light broad in a most suitable way that makes their designed suppliers play the best performance. If customers insist to use their own light broads, the best way is to let LED manufacturers design the particular power suppliers for them.

 

What is the suitable working current for LED?

Theoretically, LED working current is 20mA. Some manufactures set their LED current (the current pass though LEDs during their work) as 20mA, leaving no margin. It is improper to do so. In fact, LEDs will generate a large amount of heat under a current of 20mA. Even if we can keep the entire circuit to provide a constant current, it still can cause damages on LEDs, reducing their working lives. After many tests and comparisons, technicians have proved that the best working current for LED is 17mA.

 

What is the most suitable voltage for LED Grow Lights?

Normally, LED working voltage is around 3.0V-3.5V, most of them are 3.125V.