A novel measure to analyse the reliability of LED luminaires

Abstract

LED luminaires are the most promising lighting solutions for general lighting in the current era due to their durability and lower power consumption. Reliability of LED luminaires is dependent on the electrolytic capacitor at the output stage of the LED driver as this is the weakest link failing the luminaire. So, it is required to develop a general measure to understand the effect of capacitance on the drive current and thus on the light output to analyse the reliability of the LED luminaire. To investigate the effect of capacitance and equivalent series resistance (ESR), a capacitor bank setup is developed, with values ranging from 0.017 μF to 860 μF. Six LED luminaires of different ratings and manufacturers are selected and drive current, and lumen output for each is studied. Based on the drive current ripple patterns observed, capacitors are classified into two classes, and also percentage flicker is determined. As driver capacitors decide the amount of ripple in the output current, a generalised measure of capacitance and ESR limit is established for the LED luminaire to work reliably. The work also helps in formulating metrics for determining the service life of an LED luminaire accurately.