Conducted EMI modeling and reduction in a flyback switched mode power supply

In the design of power electronics systems, electromagnetic compatibility (EMC) should be well attended as well as electrical, thermal and mechanical issues. This paper provides a characterization approach for conducted electromagnetic interference (EMI) in switching mode power supplies. The EMI model outlined in this paper considers main parasitics of the components to forecast EMI phenomena. The experimental results validate that the derived model can roughly predict EMI. To attenuate EMI in the prototype converter, spreading spectrum is employed and its influence on EMI spectra is presented via measurement.