A novel framework for a wireless smart lighting system

Abstract

Smart lighting systems, which evolve from traditional lighting control by utilizing feedback from user inputs and integrated sensors to manipulate the light output has been hailed as the next step in the evolution of lighting technology. Its future is bright; however, barriers to its widespread adoption include average energy saving returns that do not justify the initial investment cost, inadequate functionality and a lack of light quality control. This thesis seeks to address these problems by expanding the capabilities and enhancing the performance of smart lighting systems. To achieve this, a novel smart lighting framework featuring a tunable LED-based light engine with eight primary emitters and a custom-built LED driver, an intelligent controller, wireless connectivity complete with sensor integration via a wireless sensor module and graphical user interface was designed and developed. The inclusion of the controller and wireless sensor module allow for a highly customizable lighting system by facilitating the seamless integration of novel lighting control algorithms that are designed to enhance the system performance. In this thesis, three distinct smart algorithms were developed, implemented and tested experimentally using the smart lighting framework. Firstly, a closed-loop energy-saving algorithm was designed to enhance the energy efficiency of the lighting system. Compared to currently available energy-saving lighting systems, this control system exhibits high energy savings of up to 62% under different usage patterns, verified experimentally in continuous and discrete usage pattern environments. Moving beyond energy-savings, an open-loop chromaticity/correlated color temperature (CCT) control algorithm was realized to manipulate the produced light towards target color coordinates via an iterative optimization process. This control scheme was established to work accurately with eight primary emitters, which improves upon current chromaticity/CCT control systems that are limited to bi-color or RGB emitters. Finally, a closed-loop spectral replication algorithm was developed to allow holistic replication of target light spectra for smart lighting systems. This algorithm offers a novel approach compared to other lighting control schemes by allowing direct manipulation of the produced light SPD while also accurately maintaining other important light characteristics such as the color rendering index, CCT and chromaticity.