Interferences in AC–DC LED Drivers Exposed to Voltage Disturbances in the Frequency Range 2–150 kHz

LED lamps are both potential victims and sources of electromagnetic disturbances in the frequency range between 2 and 150 kHz (“supraharmonics”). Immunity tests for this frequency range are important due to possible performance degradation of light intensity with LED lamps. In this paper, the impact of supraharmonics (SHs) on light intensity from LED lamps has been analyzed. LED lamps have been exposed to SH test profiles based on IEC 61000-4-19. Three phenomena that impact light intensity metrics have been observed and explained by models: 1) earlier conduction/later blocking caused by SH voltage, 2) intermittent conduction depending on the SH impedance of the LED driver, and 3) reverse-recovery current of the diodes at higher frequency. It is observed that impact on the light intensity metrics shows up around the beginning and end of the conduction period. The results reveal that the profile of the SH voltage could cause deviations in the modulation depth and the average light intensity. The immunity of LED lamps against SHs shall be further studied and discussed by research groups and standard committees.