Performance Assessment of Light-Emitting Diodes Using Multi-Domain Compact Models

In this work, guidelines are provided for designing illumination-grade light-emitting diodes (LEDs) into luminaires. A generalized concept of deriving a multi-domain compact model of LED from data-sheet information is discussed, however, the process described can be applied to the design of any kind of LED luminaire. The most critical aspect of LED luminaire design is to decide on how many LEDs are required to meet the design goals. The rest of the design process revolves around the number of LEDs since it directly impacts the optical, electrical, and thermal aspects of a luminaire. The design process is not simple as it seems, it is not estimating the number of LEDs based on photometric characteristics listed on their datasheets and divides the target lumens from the design goals by that number. However, this approach looks too simple but not always will lead to a design that will meet the application’s illumination requirements. The photometric properties of a LED are dependent on a variety of factors, including drive current and junction temperature. The accurate number of LEDs can be estimated only when the inefficiencies of the optical, thermal and electrical systems are accounted for in the design process. This work serves as a guide to estimate some of the major losses.