# Average current mode control on secondary side of a transformer?

#### SiCEngineer

Joined May 22, 2019
299
I have been looking through the famous app note on Average Current Mode Control by L. Dixon,https://e2echina.ti.com/cfs-file/__...-Mode-Control-of-Switching-Power-Supplies.pdf.

He gives many examples on how to use current mode control for input/output current and for flyback topology. I am quite novice when it comes to control theory, so I was wondering - is it possible to use average current control on the secondary side of an isolated DC/DC converter, such that we control what is essentially a "DC" current (with small ripple). My converter is a buck converter that is cascaded into a half bridge resonant converter, and controlling the buck output inductor current does not seem to be sufficient in regulating the converter under transient conditions. I thought maybe I could try controlling the secondary current and modulate the buck converter according to this for tighter control.

So, is it possible? Is it recommended?

#### Delta prime

Joined Nov 15, 2019
841
Can I see a schematic ?. Oddly enough my colleagues and I are developing (assessing strategies) of something similar. A current-mode converter with a secondary LC filter has been analyzed and modeled in “Secondary LC Filter Analysis and Design Techniques for Current-Mode-Controlled Converters” and “Three-Loop Control for Multimodule Converter Systems.” However, an assumption that the secondary inductor has a much smaller inductance value than the primary inductor, which is not always eligible in real applications..

#### SiCEngineer

Joined May 22, 2019
299
Can I see a schematic ?. Oddly enough my colleagues and I are developing (assessing strategies) of something similar. A current-mode converter with a secondary LC filter has been analyzed and modeled in “Secondary LC Filter Analysis and Design Techniques for Current-Mode-Controlled Converters” and “Three-Loop Control for Multimodule Converter Systems.” However, an assumption that the secondary inductor has a much smaller inductance value than the primary inductor, which is not always eligible in real applications..
Hello mate! Apologies for the late reply. I will attach schematic to this reply. There is an additional CLC pi-filter on the output to remove ripple, so the document you sent I suppose could be applicable. I just can't get my head around the theory.

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