Smart And Fault-Tolerant Led-Based Street Lamps

Street lamps based on light-emitting diodes (LED) have become popular in the past decade because of their low power consumption and extended life-time in comparison to conventional lamps. For the same lumen requirement, an LED-based street lamp consumes lower energy and can provide longer life. However, there is an opportunity to improve the power consumption and life-time further through the use of more intelligent lighting control. For example, we can take advantage of the variations in the ambient light over time as well as over geographical regions to let the lamp adapt itself and provide just the required amount of lighting. Similarly, we can render the LED array more tolerant to faults by introducing design changes such as redundant columns and bypass diodes. In this paper, we describe such a smart control scheme and study the benefits it provides in comparison to a simple control scheme. We show that we can get a further improvement of 11.3% in energy and a 19x increase in life-time through the use smart lighting control. We also propose the use of a hybrid lamp that uses a mix of yellow and white LEDs to provide a form of street lighting that is more acceptable than pure-white lamps.