According to the disadvantages of traditional tunnel lighting system, such as high energy consumption and single control mode, this paper develops a practical tunnel Zhao Mingzhi based on LED
Energy control system. This paper discusses the development and application of the intelligent control system of tunnel lighting based on LED from the aspects of system architecture, control strategy, communication network, software realization and so on. It also introduces the application of LED lighting system based on PWM Technology
The principle, hardware structure, working mode and technical points of the dimming control module are presented.
Aiming at the disadvantages of high energy consumption and single control mode, a practical intelligent control system for tunnel lighting based on LED is developed. From the system architecture, control strategy, communication network, software implementation
In this paper, the development and application of the intelligent control system of tunnel lighting based on LED are discussed, and the principle, hardware structure, working mode and key points of the LED lighting dimming control module based on PWM technology are introduced. The Department of
The system can according to the outside illumination, time, traffic information collection, automatically adjust the brightness of the tunnel lighting, in order to maximize the energy consumption, improve the efficiency of the management and operation of the tunnel, has certain application value.
Key words tunnel lighting, LED lighting controller, energy saving
The tunnel has shortened the road mileage and improve transport efficiency, utilization of underground space saving land, ecological environment and other advantages, more and more city highway tunnels, underground tunnels, tunnel, Lake Tunnel etc.
Various forms of tunnel operation and use. Tunnel lighting and road lighting requirements are different, the tunnel also needs to be lit during the day, and the problem is more complex than the night, the lighting system is the most important facilities in the tunnel mechanical and electrical engineering
One, and it is also the basic guarantee vehicle traffic safety in the tunnel, and reasonable lighting control strategy and lighting and strategy control system is an important factor to ensure the lighting system is safe and reliable, high efficiency and energy saving.
Most of the existing tunnel lighting intelligent control system adopts the time sequence control method, which mainly aims to increase the number of working lamps by reducing the number of different lighting circuits. This control method is simple and reliable,
But not fully take into account the influence of environmental factors on tunnel lighting, such as weather conditions, air condition, tunnel traffic volume and speed of the illumination requirements, can not fully meet the requirements of the tunnel lighting, and high energy consumption. With semiconductor
With the rapid development of lighting technology, more and more energy efficient LED lighting lamps have been used in tunnel lighting system. Compared with traditional lamps, LED lighting has the advantages of low power consumption, high reliability and long life,
The utility model is a green lighting source which is in accordance with environmental protection and energy saving. This paper puts forward the realization and application of LED tunnel lighting intelligent control system from the point of view of improving the control strategy,
To provide a complete solution for high power LED tunnel lighting intelligent control system.
2 tunnel lighting intelligent control system architecture
The tunnel lighting intelligent control system is composed of the main control computer of the monitoring center, the LED tunnel lighting intelligent controller and the data communication interface. The intelligent lighting controller adopts the field sensor
Sets the value of the tunnel illumination value, the tunnel illumination value, traffic flow, vehicle speed and other data, and upload the data to the monitoring center. The main control computer calculates the current brightness parameters of each tunnel and each section according to the setting light control logic
The light control command is sent to the tunnel LED lighting controller through the communication network. Lighting intelligent controller using freesacle PowerPC8247 processor, the software to operate Linux
The system is a working platform, the communication mode can choose CAN network, wireless ZigBee or RS485 bus. Figure 1 is the LED tunnel lighting intelligent control system schematic diagram.
As shown in Figure 1, the tunnel lighting controller collects the detection signal of the sensor, such as the vehicle detector and the light intensity detector. System control strategy
Just as follows: under normal circumstances, in the absence of the vehicle to enter the tunnel, according to the difference between the inside and outside of the tunnel light intensity detected, open the corresponding basic lighting only in the tunnel; the vehicle detector detects the vehicle to enter the tunnel, the tunnel opening
To strengthen the road lighting; when the detected vehicle to enter the tunnel, the vehicle is in front of a corresponding distance illumination strengthened; once detected behind the vehicle will follow up the back of the vehicle to enhance the lighting off, and turn down the basic picture
Brightness. At the same time, according to the detected light intensity value, it can also judge the time of day, cloudy day, day and night.
According to the characteristics of the tunnel, the tunnel lighting intelligent control includes the entrance lighting control, the transition section of the lighting control, the basic area lighting control (a number of) and export area lighting control. Tunnel lighting controller
Received brightness adjustment command, automatically adjust the lamp power supply output current (PWM mode duty cycle), change the brightness of the LED tunnel lights or working conditions. The main control computer can detect the current
The illumination of the tunnel illumination is used to judge whether the current illumination meets the requirements of the tunnel lighting, and if not satisfied, a new control command is issued to the LED tunnel lamp to change the illumination of the tunnel. In order to ensure traffic safety, dimming system
Adjust the brightness of the tunnel, the use of the gradual change of brightness control, step by step to achieve the target brightness, in order to avoid sudden changes in the brightness of the unsafe factors.
The system can be carried on a single lamp single control and group control of regional lighting control strategy can be modified according to the actual situation, this can save a lot of power, effectively reduce operating costs.
3 system communication network structure design
This system adopts the bus network topology structure, communication mode can be used CAN bus, 485 bus or ZigBee wireless mode, corresponding to different types of intelligent LED lighting receiving interface controller .
LED tunnel lighting intelligent control system topology as shown in figure 2:
Data transmission using CAN and RS485 bus communication technology, require specialized investment in the laying of communication lines, when the data transmission bus and the LED lamp power lines laid in parallel, there will be a high voltage pulse coupled invasion
The quality of communication is easily affected. Zigbee is a new short-range wireless communication technology based on IEEE802.15.4 protocol, which can effectively solve the above problems
Multiple, decentralized, high data transfer rates are not required in the field of control applications. The tunnel lighting intelligent controller in this system is equipped with ZIGBEE module, which can carry on the ZIGBEE network simply and quickly. Figure 3 is
Schematic diagram of ZIGBEE wireless network lighting control.
Relative to the stage lighting needs rapid changes in the scene, the tunnel lighting dimming changes slowly. Therefore, a more suitable DALI (Digital) is adopted in the choice of communication protocol
Addressable Lighting Interface: digital addressable lighting interface protocol standard. DALI is an interface standard for data communication between lighting control devices
The biggest feature is available and accurate control of the system of LED lamp independent addressing, although these lamps are the same or different loop loop in power, but in the lighting control and power lines without direct contact. The.
It brings great flexibility for the control, and can be designed according to the needs of the lighting scheme to meet its needs, even in the process of operation after the installation can still modify the control parameters, without making any changes to the line. Using DALI
The function of the system is relatively small, the structure is simple, the installation is convenient, the debugging is also very convenient, and can realize many functions which can not be realized by the intelligent lighting control system based on the loop control.
At the same time, DALI technology is a two-way communication, not only can send control command and feedback controller and LED lighting source working state and fault information, to the operation and maintenance and centralized management has brought great
Convenience. The DALI protocol uses digital lighting control technology, the advanced nature of the There is nothing comparable to this precise control, standardization and technology and excellent openness, the general digital lighting technology rapidly in the field of lighting control
And the application of digital lighting is becoming a trend of design and application.
4 LED tunnel lamp intelligent control unit
In the tunnel intelligent lighting control system, LED lamp intelligent control unit is the core of intelligent lighting control system, which receives the control commands from the tunnel lighting controller, and control the current flowing through the LED, so as to achieve the purpose of regulating light.
To a company chip, for example, a single chip rated current of 350mA, control the current through the LED can control the size of the luminous intensity, the current can be controlled using the following two methods:
(1) the chopper control phase current can be adjusted continuously from 0 to 350mA, but the use of such programs need to re design of switching power supply, power supply in the face of many LED manufacturers, adaptability is poor, is not conducive to the popularization of.
(2) to the rated output current of various manufacturers LED lamp power supply for the reference value, using PWM (Pulse Width Modulation: pulse width modulation) average output current control power supply to achieve dimming control.
The LED lamp dimming controller using PWM modulation mode of the system, the luminous intensity of 0 ~ 256 continuously adjustable, can be connected between the lamp power and LED module, has nothing to do with the lighting power supply according to the original.
Requires up to 6 LED modules. Because it does not need to change the original structure of the lamp power supply, so it has wide adaptability, high control precision and good stability. LED lamp intelligent control unit system structure shown in figure 4.
The LED lamp manufacturers to adopt the serial parallel structure of LED lamp according to its own characteristics of lamps, LED lamps will be combined into 1 or several modules, each module in the series structure and parallel structure is adopted between modules. The intelligent control unit of the LED lamp controls the PWM modulation signal of each module according to the received control command, and can realize the light modulation or the combined dimming.
In the choice of the PWM modulation frequency, it should be considered that the LED lighting in the tunnel may have the difference frequency effect with other light sources. In addition to the LED lights in the tunnel, may also be equipped with high-pressure sodium lamp, fluorescent lamp, etc.
Frequency is too low, there will be a serious difference frequency strobe, seriously affect the safety of the tunnel driving. However, if the PWM modulation frequency is too high, it will increase the switching loss, resulting in power supply, power efficiency is reduced. According to many
The study of the test, the frequency of the PWM modulation signal in 2 ~ 10kHz
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