NEED HELP NOW! reg. loss in induktor.

[TroelsM]

If an SMPS is operated in continuous mode the current in the output induktor will be a DC-current with an small superimposed AC-ripple.

When calculating the loss in the induktor I would guess that I should add the loss for the DC-current and the loss for the AC-ripple?

The DC-loss is a function of the DC-resistance and this resistance is usually very small. The AC-loss is a function af eddy-current-resistance in the inductor and this "resistance" is many times larger.

My problem is:
When calculating the loss, do I use formula 1) or 2)
1): Ploss = Rdc*Idc^2 + Reddy*Iac^2
2): Ploss = Rdc*(Idc+Iac)^2 + Reddy*(Idc+Iac)^2


Please help me, and please do it now! -I have an exam in 4 hours and 10 minutes....

Troels

 

[phase_accurate]

Hi Troels

From a quick shot at it I'd say it is:

3): Ploss = Rdc * (Idc^2 + Iac^2) + Reddy * Iac^2

But don't sue me if it is wrong.

Regards

Charles

 

[TroelsM]

Thanks

I figured it out. BTW my grade was 11 (0 to 13 scale)!

Troels