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The power electronics industry is now facing the higher power density design challenge to keep size shrunken but still meet the strict requirement for electromagnetic compatibility regulation. In this study, we investigated the conducted emission from a high-efficiency and compact size ac-dc switching power adaptor with flyback converter topology, and analyzed the root cause of EMI problem to further apply mitigation techniques for achieving regulation compliance. We first performed conduction emission test to obtain the emission profile for later result comparison and validation, and then utilized the ANSYS Simplorer and Q3D simulation tools to establish the analysis model for the fly-back switching power adaptor. After the simulation of the power module model being validated for effectiveness, we finally implemented the filtering scheme and PCB layout modification to effectively reduce the conducted noise and meet the product standard requirement.

According to CISPR 16-1 & ANSI C 63.4 standard requirements, to implement EMI radiated emission measurement needs to use accuracy antenna factor (AF). The Standard Site Method(SSM) of antenna calibration is most popular technology in the EMI sector. In Taiwan, the SSM calibration technology is also to set up in BSMI WUDA Antenna Site to calibrate broadband antennas (30MHz to 1GHz). This paper will simply describe the theme of antenna calibration, introduce the structure of this calibration site and describe the measures used to control its calibration uncertainty below 1 dB.