An analysis of harmonics from LED lamps

Light Emitting Diodes (LEDs) are versatile, energy efficient when compared to the conventional light sources. LEDs represent a transformational change in how light is produced. However, there are significant differences between conventional lighting sources and LEDs in terms of voltage and current operating requirements which may affect the power quality (PQ) of AC mains supplying the LED bulbs. Therefore, this paper investigates harmonic generations from LED bulbs available in the market. It is done by conducting laboratory tests on various LED lamps and tapping the load current behaviour under different conditions. Then frequency domain analysis is performed to investigate the generated harmonics. Harmonic levels of different wattage, various branded LED bulbs are experimentally evaluated and compared. The results show that most of the LED lamps produce high level of harmonics with reference to the IEC 61000-3-2 standard.