Light intensity variation (flicker) and harmonic emission related to LED lamps

Abstract

This paper discusses two power-quality aspects of LED lamps: harmonics and flicker. Measurements have been performed of 24 different LED lamps: the harmonic current spectrum and light intensity variations have been measured. To enable an objective comparison, the light intensity variations were measured for all the lamps when exposed to the same voltage magnitude variations. Results show a large variety in harmonic emission between different LED lamps indicating that different technologies or different components are being used within the LED lamps. Moreover the results show a large variety in light intensity variations when different LED lamps are subjected to the same voltage fluctuations. A clear correlation was found between harmonic emission and sensitivity to voltage magnitude variations. Lamps with low light intensity variations are also the ones with the highest harmonic current emission. No clear relation between active power or price and sensitivity to voltage magnitude variations was found.