LED Lamp Flicker Assessment Under Distorted Grid Voltage in Both Harmonic and Supraharmonic Ranges

Supraharmonic (SH) background distortions are blamed for light flickers produced from LED lamps with no clear evidence in literature. Consequently, this article is structured to investigate the effect of the background distortions in the harmonic and SH ranges on the light flickers produced from low power LED lamps that are widely used in residential applications. Four scenarios are performed: The first and second scenarios are done by exposing the LED lamp to a background distortion with harmonic and interharmonic voltage components, respectively. The third and fourth scenarios explore the impact of the grid voltage distortion in the SH range with frequencies that are integer and noninteger multiples of the grid frequency, respectively, on LED lamp flickers. The conducted study comes to the conclusion that visible flicker only appears for scenario 2, in which the visible flicker effect is in inverse relationship with the interharmonic frequencies. In both scenarios 1 and 3, no visible flicker is detected. In scenario 4, the light flicker is negligible. The observations are carried out experimentally on a commercial LED lamp. Then a mathematical analysis is provided to explain the observations in the four scenarios. The main outcomes are validated through a simulation study.