EMC failure for multi inductor PFC?

[cupoftea]

Hi,
We received an SMPS with PFC. It was 150W, 90-265vac.
The PFC inductor was several (four) equal_inductance offTheShelf smaller inductors in series.
Sounds like a great way to do it cheap..but surely all those switching nodes being at each inductor to inductor space...surely very difficult to pass high frequency common mode conducted emissions and radiated emissions?

 

[Easy peasy]

if you scope the joins you will find a shed load of ringing too . . . .! bad for emc

 

[cupoftea]

Thanks, yes , i was thinking of RC snubbers across each inductor?

 

[Easy peasy]

I was thinking of ice cream, do you have scope captures of the ringing ?

 

[cupoftea]

Sorry no, the engineer who is doing this with my assistance, decided on a single 400V rated offTheShelf inductor , (MSS1812 470uH) for his 150W ACM Boost PFC stage, instead of two 400V rated, offtheshelf MSS1583 (330uH) inductors in series.

His Vout is 400V with +/- 5V ripple. His output overvoltage is set to 427V.