Passive filter design for reducing harmonics in light emitting diode bulb

Harmonics reduce power quality and increase inefficiency. Although light emitting diode (LED) bulb has been considered more efficient than previous bulb technologies; its internal circuits potentially generate additional problems. This paper has surveyed 6 LED bulb samples and measured the harmonics generated by the internal circuits. As a result. 7 Watt type B LED bulb produces the highest 3rd order harmonics current which is incompatible with IEC61000-3-2 Class C. A prototype of LC filter is designed to decrease the harmonic level. The measurement shows that the designed passive filter is able to reduce at least 81.3% of harmonics