Optimal Design of Light Distribution of LED Luminaries for Road Lighting

摘要

Conventional road lighting luminaries are gradually upgraded by LED luminaries nowadays. It is an urgent problem to design the light distribution of LED luminaries fixed at the former luminaries arrangement position, that are both energy-saving and capable of meeting the lighting requirements made by the International Commission on Illumination (CIE). In this paper, a nonlinear optimization approach is proposed for light distribution design of LED road lighting luminaries, in which the average road surface luminance, overall road surface luminance uniformity, longitudinal road surface luminance uniformity, glare and surround ratio specified by CIE are set as constraint conditions to minimize the total luminous flux. The nonlinear problem can be transformed to a linear problem by doing rational equivalent transformation on constraint conditions. A polynomial of cosine function for the illumination distribution on the road is used to make the problem solvable and construct smooth light distribution curves. Taking the C2 class road with five different lighting classes Ml to M5 defined by CIE for example, the most energy-saving light distributions are obtained with the above method. Compared with a sample luminary produced by linear optimization method, the LED luminary with theoretically optimal lighting distribution in the paper can save 40% of the energy at the least.