Study On Intelligent Led Street Lighting System Powered By Stand-alone Photovoltaic Power Generator

Almost every country in the world today is facing increasingly presented problems of energy crisis and environmental pollution. Therefore, their effort to address such problem is focused on the development and utilization of new-type renewable source of energy, energy saving and reduction of greenhouse gas emissions, which are considered the basic strategy of these countries for sustainable development. China is a country with vast territory, abundant resources and large population. The energy consumption for the illuminating purpose is enormous. Against this background, this study is initiated in an attempt to develop an intelligent LED street lighting system powered by stand-alone photovoltaic generator by combining the application of new-type energy with state-of-the-art lighting technology. The system is powered by solar energy which is recognized as being clean, environmental friendly and inconsumable. The solar photovoltaic system energizes high-efficient and energy-saving LED assembly to achieve street lighting.The study is based on the assumption that each street lamp serves to be an independent system. Appropriate design was conducted for SCM programming and basic driving circuitry to control the system for automatic switching among the three working modes, or charging, lighting and waiting. When natural illumination is adequate enough, the system automatically shifts to "charging" mode. In order to protect energy storing elements, the control system need to perform a real-time check on the remaining electric charge so as to activate fast recharge, supplementary charge or trickle charge; when natural lighting is not adequate, the control system will first check the remaining charge of the energy storing element. If the remaining charge is more than enough, a power supply to LED energizing unit is enabled and the system is in "lighting" mode; if the remaining charge is not adequate enough to energize the LED, the system shifts to "waiting" mode in which it will neither charge nor discharge. In addition, a two-stage lighting technique is incorporated in the system to further extend the continuous lighting time.The study of this system is intended to achieve the combination of photovoltaic power generation and LED lighting and make some exploratory innovations to break through the technical bottlenecks that hinder the popularization of the technology. We believe that this study is instrumental not only to the design of a new street lighting system that features in energy saving, environment friendliness, high efficiency and stable performance, but also popularization and promotion of wider application of new source of energy and new lighting material, hence finding a new, innovative way for new energy application, energy saving and gas emission cut.