Research And Design On The Intelligent Traffic Signal Control System Using Solar Energy

Traffic is the lifeblood of economic activities in cities and plays an important role in the urban economic development and people's living standard improvement. However, with the accelerated pace of urbanization, rapid increasing in motor vehicles, people are increasingly troubled by traffic jams, traffic accidents, environmental pollution and energy shortages. Therefore, it is imperative to establish the traffic signal control system for domestic demand of China.In this dissertation the traffic signal control system is researched and designed, which is made up of the host and the extension part. The traffic signal control system adopts 2-bus model and by which it can both transmit power and information, also can control the traffic light reliably. The host and all the direction indicators, countdown timers, ultrasonic detectors adopt 2-bus model in parallel which solves a complex issue of many signal connections between the light groups and the host. It is applicable to a variety of shapes of traffic intersection. The 2-bus model has a simple structure, good scalability and can be repaired easily.In the design of the host part, the main power supply employs solar energy and the auxiliary power supply adopts 220V AC and lithium-ion batteries.220 V AC which is rectified by APFC and then bucked through the DC-DC supplies power for the night and cloudy days. Lithium-ion batteries are used for emergency power supply. It saves the electricity and prevents traffic gridlock from power outages of the city, so as to improve the reliability of the traffic control system.In the extension part efficient current source based on a floating-based way of driving switch is designed, which provides many current sources and drives countdown timer and direction indicator in constant current. It increases the working life of the traffic light and the own loss of the current source is very small, also it is stable. The countdown timer and the direction indicator only use red and green LEDs. The red and the green can display red, yellow and green when mixed in proportion. Using short-circuit mode to drive LED with opto-coupled SCR switch can not only reduces the number of current sources but also makes the system more stable and reliable.Ultrasonic detector is used in the traffic signal control system. According to the traffic flow detection MCU can intelligently allocate time in proportion at crossings. It can alleviate traffic congestion phenomenon.