Development of street lighting system-based novel high-brightness LED modules

Abstract

The development of high-power light emitting diode (LED) for street lighting is growing continuously owing to its greater energy efficiency, long operating life and light control. Users of street lighting are compelled to adopt this technology over traditional light sources. An alternative solution based on a novel 9LEDM (9-LED module) and adaptive driver is shown. The design of the 9LEDM is derived from the thermal, photometric, power electronics techniques to meet the application of street lighting. The 9LEDM performances with a price less than 1$/Watt (W) and luminous flux higher than 110 Lumens (Lm)/W compared with traditional ones. Furthermore, several restrictions of driving the solid-state lighting loads are overcome by an adaptive street lighting driver with an AC/DC converter of a quasi-resonant operation flyback topology and with Soft Startup, Full ON, Half ON functions by sensing the ambient light and working temperature. Finally, a high performance/cost 50 W pole head as a design example is conducted to illustrate the complete design process, and the results from the demonstration projection with two pole heads of 50 W for a 12 m pole show a luminous intensity range from 38 to 19 lux with a heat sink temperature of 58degC and an energy saving more by 72% compared with conventional street lighting after three months of running.