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I am not sure if your way to do the estimation of permeability drop is fine. I use the permeability vs DC bias coefficients.
This is the datasheet plot
Using coefficients on table
I can calculate the permeability drop.
This is my calculated curve
As you can see, it matches very well the...
I don't see any problem with this inductor design. If at current peak conditions the A*T is too high, this will just implie that the effective inductance is much more lower than the inductance at 0A. Then, it can result in higher losses on the core due to the high frequency components of the...
Hi FvM, maybe I did not explained properly,
You are right the gap change itselft does not change the leakage directly. What it is clearly changed is the ratio between Llk and Lm.
I generated this table some time ago running FEM simulations. The only change between...
Umm, I don't completely agree with it. Leakage is directly related with the coupling between windings but there are other effects that modulate the leakage two. When you add a gap between the cores, the flux finds a easier way to go out of the ferrite when it is crossing the gap. In other...
Hi Cupoftea,
I remember to find this discrepancy some time ago. My conclusion was that the actual depth is 5.4mm. If you check the PQ3230 coil from TDK, which has very similar dimensions, you can se the winding area is 104mm2.
https://www.tdk-electronics.tdk.com/inf/80/db/fer/pq_32_30.pdf
Well, it looks like if there is not enough current on the magnetizing inductance when the mosfets are turned off, the diode from ground to the switching node is not direct polarized, because the current is drawn from the Coos of the mosfets. Then, the node does not reach 0V and so, the bootstrap...
Using manufacturer plots for Power loss density vs Flux density for different frequencies you calculate the parameters used on the Steinmentz expression (k, a, b).
Regarding the case the current is not sinusoidal, that you can do is to use Furier to get the Flux magnitude for the fundamental...
Hi Jadeit,
I am not quite sure I understood your exposition. However, I am going to try to describe the trafo based on the information you have.
In short, the transformer only has two windings.
Turns ratio between primary and secondary is 9. Assuming X turns on the secondary, the primary will...
Hi Mike,
What diode is your using as a boost diode?. Due to it is a boost configuration, the critical component regarding ringing on the switching node is the boost diode. It must be a low trr diode or SiC ideally, otherwise, there will be a big ringing due to the recovery reverse current.
Byjuncal
Hi Klauss and everyone, (this is my first message here),
Indeed, it is really trickie to design a completely quiet SMPS if the operation conditions are very differents.
I have some experience facing audible noises problems. Many people, directly point to the magnetics as the principal source...
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