标签：LED area lighting

Typical LED driver solutions for LED area lighting power structure

LED drivers used for LED area lighting need to meet the some standards for power factor (PF) and harmonic content, like IEC61000-3-2 of EU International Electrical Union (IEC) standard has explicit specification for harmonic content of lighting applications with power consumption more than 25W – the total harmonic distortion (THD) should be less than 35%. However, production satisfied IEC61000-3-2 does not mean that they have a power factor that more than 0.9. According to relevant regulations of the United State, lighting devices or other electrical appliances should have a power factor no less than 0.9 and THD more than 20%.

 

Typical LED driver solutions for LED area lighting power structure

 

Most of area lighting applications are used outdoors. They may probably be subjected to all sorts of harsh environment, the overall service life will be definitely affected. These problems can be solved by improving the overall structure design, reducing the heat generation and increasing the power efficiency of LED drivers. Reducing heat dissipation can be realized by insolating LED heat resources and G24 LED drivers to enhance the stability of the entire system.

 

LED lighting products can be intelligently controlled. Traditional road lighting applications can realize automate control via timer and optical sensors. This kind of intelligent control is relatively complex and more likely failure. Intelligent controls for LED area lighting applications are mainly depended on PLC and wireless control technologies, which is more stable and flexible, such like time-based centralized control for brightness; brightness control based on traffic flow sensors; brightness control based on sensors used to detect people and vehicles. LED intelligent control technology is able to save more energy, having much less impacts on security. Double brightness control is a typical LED intelligent lighting control applications in LED area lighting industry. These lamps can automatically adjust self-brightness (two or more levels) in accordance with surrounding light conditions. This solution can be used in many places, like parks, gas stations, parking lots, stares, freezers. LEDs can be instantly turned on and off or adjusted according to actions or activities. Once detecting actions or activities, LED lamps with double brightness control systems can provide 100% brightness. The brightness will drop to only 20%-40% when no actions or activities are detected. Intelligent control makes energy-efficient LED lighting fixtures save more power.

Application requirements of LED area lighting

The main function of LED drives is current-restriction in many conditions to keep LED lights chips from current surges and other operation faults. Most LED drives can guarantee a certain level of safety to effectively prevent electrical fires and mechanical friction fires. In the field of LED area lighting, outdoor temperature will bright greatest challenges to LED drives. Some drives even have to work under high voltages, such like 277VAC, 347VAC, 480VAC.

 

The main function of LED drives is current-restriction in many conditions to keep LED chips from current surges and other operation faults.

 

LED drives used in area lighting should satisfy a certain level of power factor (PF) or standards of harmonic contents. Such like IEC61000-3-2 standard issued by IEC has clearly restricted the harmonic contents of lighting equipments (C type) that have power consumptions larger than 25W. In fact, based on general IEC standard, many countries have their own certifications. A LED lamp with a PF of 0.9 can completely meet the requirements of IEC61000 standard but still incompetent in America’s lighting market. In order to protect domestic LED industry, the American standard for high-power LED lighting products (larger than 25W) has an additional requirement: THD must be lower than 20%.

 

Most LED are lighting applications were used outdoors, which will suffer all kinds of serious environments. It requires LED products with longer working life. It is said that the entire system design has significant influence on service life of LED components. Using LED drives that generate less heat, consume less power and have higher efficiency is rather important. Besides, the improvement of cooling sections and protection circuits is also a key point to increase the reliability of the entire system.

 

LED lighting applications can be intellectualized. Generally, traditional LED street lighting realized intelligent control through timing devices or other light intensity sensors. While LED area lighting have more accurate intelligent control based on power line communication (PLC) or wireless control technology, such like the concentrated control based on time output and light output; brightness level control based on vehicle density sensors; Through intelligent controls, LED lamps can be turned on and turned off or self-adjust brightness level depending on the nearby conditions. Provide full lumen output when activities or objects are detected, while only provide only 20%-40% lumen output in the dormancy state.

Problems for LED area lighting

With the enhancement of people’s awareness of environmental protection, the lighting industry paid more and more attention on energy consuming problems. In accordance with related statistics, in the process of energy consuming, more than 20% electricity is used for lighting. Improving the lighting efficiency to furthermore reduce the energy consumption became an impending issue. Therefore, high-efficiency LED area lighting has been put forward as a hot topic.

 

With the enhancement of people’s awareness of environmental protection, the lighting industry paid more and more attention on energy consuming problems.

 

In the view of application areas, lighting include residential lighting, industrial lighting, street lighting, restaurant and hotel lighting, retails and service lighting. In the view of power consuming, lighting also can be divided as low-power lighting high-power lighting. Typical high-power LED area lighting applications include LED bollard lamps, LED wall washer lamps, LED tunnel lights, LED street lights, LED public security lamps, LED high bay lights and so on. All these are outdoor area lighting applications. Indoor LED area lighting applications include low ceiling lights, high ceiling lights, LED garage lighting, etc.

 

High-power LED area lighting products have many challenges: continuous working in high temperatures aggravates the light attenuation; Safety problems caused by the failure of lighting sources; design challenges in hostile environments, etc. The exiting lighting sources for high-power area lighting applications are metal halide lamps, high pressure sodium lamps, linear fluorescent lamps and compact fluorescent lamps. It is noticed that all of these lighting sources have their defects. High pressure sodium lamps have very poor CRI (only 22). Metal halide lamps have much lower lighting efficiency (only 40%). Linear fluorescent lamps have poor cold temperature performance and compact fluorescent lamps have long staring time.

 

On the other hand, with the continuous improvement of performance and production costs of high-brightness White Ray LED technology, it started to be widely used in the LED area lighting industry. Compared with traditional lighting sources, White Ray LED lights have higher light efficiency (can emit more light per Watt), have higher CRI, have better direction control capability, more environmental friendly and can be easily handled in the starting/shutting process. Intelligent technique also can be utilized in LED area lighting area. Brightness can be controlled automatically by central computers embedded within LED lamps through external mounted sensors.

 

In addition, LEDs are more reliable, which will help reduce operation and maintenance costs.