LED Street Lights. Combination Of ZigBee And GPRS Wireless Network Drivers And Monitoring System

With the growth of economy, cities are expanding rapidly. Road lighting is an important part of the city's infrastructure, lights number and installed area are growing year by year. Road lighting, which is a part of public lighting system, ensures the safety of the driver and pedestrian on road at night. During its fast development, however, there are several critical problems needed to be solved:road lighting consumes a lot of electric energy every year, it needs some measure to reduce this cost; meanwhile, an effective method or system is needed to monitor the operation of such a large number of road lights, to guarantee their proper work.Based on these considerations, this dissertation focuses on road lighting by the new light source-LED. Because LED has higher efficacy, longer life and other advantages, it is quite suitable in road lighting application. According to this assumption, firstly, this dissertation makes a research on the LED high power driver for LED road light. There are constant voltage part and constant current part in the driver. The constant voltage part uses the technology of LM-FOT APFC and LLC half-bridge resonant converter, the circuit's model analysis and design procedure are presented. Then the driver's constant current part is designed, a short-circuit protection scheme is proposed to the specified driver IC, a dimming interface is also designed to support lighting control. Experiment results prove the driver's proper function.Meanwhile, in order to implement effective road lighting monitoring, this dissertation combines the wireless technology of ZigBee, GPRS and lamp positioning technology of GPS. The control principles are illustrated in details, then, solutions and modules are chosen based on the analysis and comparison. With these modules, a ZigBee road light control gear, ZigBee-GPRS gateway and GPS positioning device are designed.Finally, the monitoring algorithm and software are proposed. To ensure ZigBee stack's proper work on road lighting control system, its hardware layer and network layer are modified and programmed. With the integration of GPRS and ZigBee technology, a stable two level wireless control network is built. The monitoring interface is built based on GPS positioning technology, so the light's position and status can be showed in real-time. The control algorithm is built with calculation of sun-rise & sun-set time and the time-dependent dimming strategy, so the LED light's on-off time and output dimming control can be precised executed.This dissertation builds an experiment platform on a road which installed LED lights. An experiment is implemented to test the function of the whole monitoring system, the results shows that the proposed the integration of LED dimmable driver and wireless control system is feasible. During the design and experiment of this project, some problems are revealed, and further improvement is proposed at the ending of this dissertation.