As a new generation of light source, LED has a series of features such as low voltage, low power consumption, small size, fast response, no pollution, high reliability and long life. Because it produces no spectrum of ultraviolet and infrared light, it has no heat and heat radiation, and can reduce the production of carbon dioxide and other room temperature gases, so it is considered to be a true green lighting source that is environmentally friendly and energy efficient. Since the 1990s, 13 countries, the United States, the European Union, South Korea, Taiwan and other countries and regions have launched semiconductor lighting plans to promote the development of LED lighting technology. At the same time, the world-famous lighting source manufacturers are also actively involved, and alliance with semiconductor material device manufacturers, and vigorously develop the LED lighting market. Driven by many forces, LED lighting technology and industry have made rapid progress and gradually entered people's daily lives.
Green lighting is a concept put forward by the US Environmental Protection Agency in the early 1990s. The complete green lighting includes four indicators: high efficiency, energy saving, environmental protection, safety and comfort. In recent years, the concept of green LED lighting has attracted people's attention. Various types and unique products with LED as a light source have also been born in the market. Intelligent lighting has also gradually received attention from everyone, especially the development of Internet of Things technology. Make smart lighting even more important. Intelligent lighting not only refers to intelligent lighting to reduce energy consumption, but also covers a variety of modern technologies such as sensing, communication, and Internet of Things. This paper discusses the application of intelligent green LED lighting technology in general lighting, landscape lighting and LED display, as well as the role of microelectronic chips such as microcontrollers, sensor interface chips, wireless transceiver chips and LED driver chips in intelligent green LED lighting. .
1 Intelligent green LED lighting technology
1.1 Intelligent LED lighting technology
The LED has good controllability, so that intelligent LED lighting technology can be developed. The intelligent LED lighting technology monitors and tracks the LED in real time through external sensors and control circuits. Automatically and smoothly adjust the brightness and color of the LED light to achieve the purpose of intelligent control of the LED. In the intelligent control software, there are complete control protocols and control methods, perfect human-machine connection, fault self-diagnosis and prompts: in hardware, with multiple communication capabilities. Such as wireless, power carrier, visible light, infrared light.
Intelligent LED lighting technology has the following advantages:
(1) Control intelligently realize intelligent lighting control, improve management level and reduce maintenance costs;
(2) Energy-saving Through reasonable management, according to different dates, different time, different illuminance, according to the operation of each functional area, the illuminance is set in advance;
(5) Beautifying the environment, good lighting design can create a warm and comfortable environment, adding to the charm of its art;
(4) Extend the life of the lamp to greatly reduce the inefficient lighting time of the lamp, thus greatly extending the life of the lamp;
(5) The uniformity of illumination is achieved by using a photosensitive sensor, which can achieve constant light in the room;
(6) Linking with other systems Intelligent lighting can be linked with other systems, such as BA system, monitoring alarm system, garage card swipe system.
1.2 Green LED lighting technology
Green LED lighting combines scientific control technology with LED lighting, bringing huge economic benefits, saving energy and capital; green LED lighting will enable people to get a high-quality lighting environment. It is good for physical and mental health, improving learning, work and living conditions; at the same time bringing social benefits, reducing air pollution, protecting the environment, and embodying the light culture of modern civilization. Green LED lighting requires energy conservation, but green lighting cannot simply stay at the level of energy conservation, but to understand its profound meaning from a higher level. At the same time meet the higher requirements for lighting quality and visual environmental conditions. It is necessary to design key links through the lighting engineering system. At the same time, it is necessary to minimize the emission of pollutants in the LED life cycle, using clean natural light sources and green materials, and to avoid light pollution.
1.3 Networked control of intelligent green LED lighting
Even after adopting intelligent green LED lighting technology, a single LED luminaire is only a point, and the effect is relatively limited. If the network control of multi-point LED luminaires can be realized, the centralized lighting management control can be unified, that is, the main control computer is within the network. The lighting equipment is controlled and managed, and timely feedback to the operators is of great significance for giving full play to the advantages and potential of intelligent green LED lighting technology.
Figure 1 shows the building LED lighting network control scheme. The total controller is connected to the Ethernet accessor via Ethernet. The Ethernet accessor controls each luminaire through the Zigbee wireless network, with modular automatic control. Manual control is supplemented. Figure 2 shows the intelligent networked control of landscape lighting. Through the lighting scene real-time control server, lighting scene editing workstation, switch light and lighting monitoring workstation and power distribution cabinet measurement control node and intelligent bridge exchange through TCP/IP Ethernet Information, to achieve intelligent control, the intelligent bridge then transmits control signals to the intelligent LED controller through the RS485 bus, and the intelligent LED controller changes the switch, brightness and color of the LED lights. The intelligent green control of the display screen is shown in Figure 3. The information to be displayed on the information production end and the service data transmission is sent to the server. After the information is transmitted and previewed, the information is encrypted and transmitted to N through a dedicated intranet or the Internet. On the LED display, the content to be displayed is displayed on the LED screen by information decryption.
2 intelligent green LED lighting technology application
2.1 General lighting technology
Figure 4 shows the smart green LED lighting application in the banquet hall. Figure (a) is the bright and cheerful lighting effect created at the banquet before the banquet; Figure (b) is the situation at the beginning of the banquet, the light is concentrated on the tabletop, emphasizing the dinner. Color scent, taste; different angles of light and light and dark, combined to form a three-dimensional visual effect; Figure (c) is a variety of lighting effects of the banquet hall under the zone control, to meet the lighting needs of different occasions, for the staff to choose; (d) is the scene after the LED is gradually turned off after the banquet. Through intelligent control, not only energy consumption is saved, but also a good artistic effect is achieved.
According to statistics, lighting accounts for more than 40% of the building's electrical energy consumption. A significant reduction in lighting can greatly save energy. LED itself is more efficient than traditional light sources, is a good green lighting source, coupled with intelligent control, can be more energy efficient. For example: central dimming control: through centralized central control, dimming, timing off LED; daylight compensation control: make full use of natural light, reduce LED lighting time and brightness; infrared sensor: human body infrared sensor to achieve people to light, people go out Event Control: Pre-programmed with special events to precisely manage lighting.
2.2 Application in landscape lighting
The goal of landscape lighting is to coordinate the landscape lighting with the landscape. Because of the “viewâ€, it is suitable for the characteristics of the building and achieve a new level of landscaping. Road lighting emphasizes brightness, while landscape lighting focuses on the beautification of the environment. Intelligent green LED lighting applications in the landscape include.
(1) Automatic switch lamp In order to save power and reduce power consumption, the landscape lighting can be switched through a pre-programmed timetable. It is also possible to control the switch light by photoelectric sensor to detect the illumination value of daylight to achieve unattended and reduced The purpose of power consumption.
(2) The dynamic automatic dimming intelligent control system automatically acquires the weather conditions of the local day through the network and automatically adjusts the color and brightness of the lighting scene according to the current weather. For example, in rainy or foggy days, the lighting control system automatically increases the brightness of the light. In the cold winter, the lighting system increases the proportion of red light that makes people feel warm in the heat. In the hot summer, the lighting system increases the proportion of blue light that makes people feel cool.
(3) Green energy landscape lighting systems usually include different lamps, such as: LED buried lights, LED floor lights, LED lawn lights, LED guardrail tubes that outline buildings, LED flexible lights with decorative plants, and LED displays. The first three types of lamps consume less power, usually within 10 weeks. You can use solar energy as an energy source to charge the battery, and then ask the LED to supply power.
(4) Fault intelligent diagnosis Quickly locate the faulty chip where it is convenient for maintenance. For chips that are in abnormal working state, for example, when the chip current is abnormal and the brightness of the lamp is too high or too low, the alarm will be issued in time.
(5) Wireless systems The current landscape lighting system is usually designed for a single building, and each subsystem is controlled by fiber optic and twisted pair. If the landscape area is large, such as a park or residential area, it is necessary to connect the subsystems conveniently and economically through a wireless local area network (WLAN), WIFI, or ZigBee technology and the current static control.
2.3 Application in LED display
LEDs have unique advantages on the display, such as far view, high brightness, large viewing angle, low power consumption and long life. Achieving a green low-power approach can be achieved by making the display hardware low-power.
(1) Continue to improve the luminous efficiency of RGB three-color LED dies, study new packaging structures or methods, improve the light extraction efficiency, and reduce the current required by the device to achieve the same luminous intensity, and reduce power consumption.
(2) Develop a low-on-voltage driving chip to provide conditions for reducing the operating voltage of the entire screen. For example, the operating voltage of the display is reduced from 5 v to 4 v, which can save 20%.
(3) Introducing low-power technologies such as synchronous rectification into the display switching power supply to maintain high efficiency while reducing the output voltage.
(4) The whole screen intelligent drive control technology controls the brightness, automatically controls the brightness of the display according to the ambient light intensity, and improves the viewing comfort while saving energy. At present, the control system generally has this function, but the actual application effect is not good. It is difficult to make stepless adjustments or damage the display. It is necessary to strengthen research in this area: combined with surveillance cameras and sensors, using image recognition technology, the content is only turned on when a certain population density is reached within the service range of the display screen, and the screen is automatically turned off when there is no viewer or the number of viewers is too small, thereby achieving energy saving purposes. .