LISN’s Effect on Electromagnetic Interference and DM Filter in Two-Stage AC/DC Flyback PFC Boost LED Driver

AC/DC conversion is widely used in various applications, such as to power televisions, telephones, vehicles, LED lighting, and so on. Despite the popularity of AC/DC conversion, it presents problems related to electrical power quality (THD, power factor) as well as electromagnetic interference. To improve power quality and reduce interference, AC/DC conversion is continually being developed using new topologies. Among the most common topologies is the PFC Boost Flyback (power factor improvement and THD reduction). Nevertheless, these converters still exhibit electromagnetic interference and may exceed the limits of EMC standards. In this article, we simulate a two-stage PFC Boost Flyback AC/DC converter, operating as a LED driver, to determine the electrical quantities at the driver's input and output. Next, we analyze conducted disturbances exceeding EMC limits in the frequency range [150 kHz-30 MHz]. In this context, we have studied and designed a DM passive EMC filter to reduce these emissions, in compliance with EN55015 Class B standards.