Studies on development of a solar-powered, colour-tunable and smart outdoor LED lighting system with wireless control

Abstract

Nowadays, outdoor lighting is an important aspect in the life of people in urban as well as rural areas mainly for security, safety and aesthetic purposes. Over the past few decades, researchers in outdoor lighting technologies are trying to increase energy efficiency, use renewable energy, reduce maintenance costs, improve safety measure, enhance visual environment and reduce light pollution. The use of solar-powered LED lighting system with remote control is a very appropriate and decisive step in achieving the goals. Therefore, the overall objective is to develop and integrate the several technological possibilities in outdoor lighting system so that it can efficiently harvest solar energy and maximize the battery life, while provides the much-needed system reliability. In this study, two remote control and monitoring based, ‘smart’, energy-efficient, long-life, low- cost and low-maintenance solar-powered outdoor lighting systems (OLSs) have been developed, implemented and successfully tested. These systems run automatically with minimal manual intervention. Moreover, they can send information related to the management and maintenance of the system to the central monitoring station through a GSM-SMS technology. Such information can be sent on a periodic, say hourly, daily or weekly basis. After analyzing the received information, the central station can also control some parameters of the remote lighting system through the same network. Additionally, on receiving the information, the state-of-health and nature of the fault of the system can be predicted from the remote monitoring station. Necessary maintenance strategy and the procedure can then be decided centrally. In this study, two types of LED lighting systems have been developed, each suitable for a specific application area. The first one is a tunable-CCT, variable-illuminance LED lighting system for colour-tunable outdoor lighting applications (e.g., residential non-living areas, public buildings and structures, gardens, parks, etc.). The second one is a fixed-CCT, three-step dimmable LED lighting system for single colour outdoor lighting applications (e.g., streets, pathways, parking lots, industrial yards, security areas etc.). The work also involves development of an improved maximum power point tracking (MPPT) algorithm derived from the Perturb and Observe (P&O) technique. This ensures the efficient operation of the PV power plant by rapidly and accurately tracking the maximum power point (MPP) of the PV array regardless of changes in environmental conditions. The methodology and implementation approaches used in this work is quite simple, straightforward, and do not require any complicated algorithm or costly component or costly tools. The hardware of the whole outdoor lighting system has been implemented by using readily available components including a low-cost microcontroller. The developed algorithm is experimentally validated by this hardware. The control algorithm is developed using C programming language. The necessary compiler and the associated tools are available as freeware. This has reduced the software development cost to a large extent.