2026-05-12 10:36 AM - last edited on 2026-05-12 1:35 PM by Andrew Neil
Planning L4981B as PFC controller as pre-stage to our DC-DC Convertor.
Will this controller work with 400Hz can it be able to maintain unity power factor in 400Hz line as it does for 50/60Hz?
Any other PFC controller recommendations will be appreciated
Solved! Go to Solution.
2026-05-13 1:10 AM - edited 2026-05-13 1:14 AM
Yes, the L4981B can potentially be used at 400Hz, but it will not be a drop-in guarantee of the same performance as at 50/60Hz.
A near-unity power factor at 400Hz is achievable, provided the PFC stage, inductor, current loop compensation, and bus-voltage loop are all designed and validated for that frequency. Key point: the controller alone does not ensure unity PF; the overall power stage design is critical.
For specific guidance on possible alternatives, further information would be needed, e.g.:
As the case with 400Hz occurs far less frequently than in typical industrial applications, there is little generally applicable guidance, so each design must be considered separately. It is very likely that the community will not really be able to help you here, so it may make sense to ask technical support at your local distributor about this.
Hope this helps?
Regards
/Peter
2026-05-13 1:10 AM - edited 2026-05-13 1:14 AM
Yes, the L4981B can potentially be used at 400Hz, but it will not be a drop-in guarantee of the same performance as at 50/60Hz.
A near-unity power factor at 400Hz is achievable, provided the PFC stage, inductor, current loop compensation, and bus-voltage loop are all designed and validated for that frequency. Key point: the controller alone does not ensure unity PF; the overall power stage design is critical.
For specific guidance on possible alternatives, further information would be needed, e.g.:
As the case with 400Hz occurs far less frequently than in typical industrial applications, there is little generally applicable guidance, so each design must be considered separately. It is very likely that the community will not really be able to help you here, so it may make sense to ask technical support at your local distributor about this.
Hope this helps?
Regards
/Peter
We’re moving the ST Community to a new platform to give you a better and more reliable community experience.