EMI filter selection for PFC

[Nick_PE]

Hello,
Can anyone share proper design guide to size common mode EMI filter for input ac line in classic boost PFC application (Vin =180 to 270V at 50Hz and Iin_rms=16A ). At 65kHz switching frequency.

 

[scopeprobe]

Generic common mode filter design guide here https://www.coilcraft.com/en-us/resources/application-notes/common-mode-filter-design-guide/ you need to have an idea of the attenuation you require.

 

[cupoftea]

https://www.infineon.com/dgdl/Infineon-ApplicationNote_EVAL_2.5KW_CCM_4PIN-ApplicationNotes-v01_00-EN.pdf?fileId=5546d4624fb7fef2014fd65081616257

...gives on PG 12 the schem of a 2.5kW PFC, and the BOM is also there. You can get some idea from this.
But yes, exact common mode inductance value needed is not calculable as it depends on the strays in your schem.
Note that the Y caps will be limited in value or else you will get too much earth currnt and trip the rcd's

If you add further diff mode inductors, then add equal to line and neutral, so its a more balanced filter, which is good for common mode attenuation