Inductor Calculations / Selection

[ElecDesigner]

Hi,

Does anyone know a good reference for calculations related to inductor design in the audio frequency range without DC bias. The actual inductor is used to tune a capacitive transducer. The inductor value is large, I have been able to calculate the number of turns fine.

I am however struggling to make sense of the other bits and pieces such as how to be sure that I my core will not saturate. I have read from lots of different sources but I'm having a mental block on how this all fits together.

 

[chuckey]

Does not your core manufacturer have application notes?
Frank

 

[ahsan_i_h]

how to be sure that I my core will not saturate.

One of the inductor equation is,
L=N\[\phi\]/I

We can write it as
L=N\[\phi\]max/Imax

Here Imax(in ampere) is maximum current before saturation, and \[\phi\]max is maximum flux(in weber) in the core before saturation. Your inductor current should stay below Imax to avoid saturation.

As you already know the inductance L(in henry) and the number of turns N, so If you can find \[\phi\]max then you can easily find saturation current Imax.

You can find \[\phi\]max from the equation below
\[\phi\]max = Bmax * Core cross sectional area(in \[{m}^{2}\])

Here Bmax(in weber/\[{m}^{2}\]) is maximum flux density before saturation. It is dependent on core. For smps ferrites it is usually 0.3 weber/\[{m}^{2}\] (Tesla).