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Calculation problem of Solid conductors with capacitors

Hello,

I am working with this circuit in flux, to obtain the impedance in a frequency range.

However, I also need the resistance and inductance values, and when comparing the resistance obtained from the joule losses with the real part of the impedance of each solid conductor they are not matching. The same happens with the inductance obtained doing flux/current and the inductance obtained from the imaginary part of the impedance.

It is something not working properly with capacitors?

Moreover, when I use the obtained Resistance and inductance values and solve the circuit analytically, it does not match with the source impedance.

I put the model attached if you want to take look of how I have defined all and if you see any mistake, I would be very grateful.

Thank you,

Yerai Moreno

Community-Pasted-Attachment-1648730635384.png

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model_test.FLU.zip

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English

Flux

v2021.2

Accepted answers

fzidat

Yes, the sum of Z1 and Z2 matches with the impedance seen by the source in the case without the capacitor.

Thanks Yerai!

So as you can see, adding Z3 without represente it in the circuit is not true, because the capacitance will add reactive energy that will have an impact on the two solid conductors. That's why you had these wrong results.

The current through the solid conductors in series is not the same with or without the capacitance.

Regards

All comments

fzidat

Hello Yerai;

There a lot of points that we should take care:

1- The solid conductors contains Joule losses, and also an active power transfered from the coil 1 to coil 2 and vis versa. Because the current in coil 1 will induce Eddy current in coil 2 and the same from coil 2 on 1. So to compute the impedance of Coil 1 and Coil 2, you should consider Active power in case you want to compare it for the total impedance seen from the source.

2- I suggest you to compute Z1 the impedance for Coil 1, Z2, the impedance for coil 2 and Z3 the impedance for capacitor. For each component, compute Active power and reactive power, and then compute the real part and imaginary part from them. Compute the equivalent Z and compare it to the one you have from the circuit. You should obtain the same thing.

Regards

Yerai Moreno Lafuente

Hello Yerai;

There a lot of points that we should take care:

1- The solid conductors contains Joule losses, and also an active power transfered from the coil 1 to coil 2 and vis versa. Because the current in coil 1 will induce Eddy current in coil 2 and the same from coil 2 on 1. So to compute the impedance of Coil 1 and Coil 2, you should consider Active power in case you want to compare it for the total impedance seen from the source.

2- I suggest you to compute Z1 the impedance for Coil 1, Z2, the impedance for coil 2 and Z3 the impedance for capacitor. For each component, compute Active power and reactive power, and then compute the real part and imaginary part from them. Compute the equivalent Z and compare it to the one you have from the circuit. You should obtain the same thing.

Regards

Thank you very much! Using active and reactive power it matches perfectly.

Yerai Moreno Lafuente

Hello Yerai;

There a lot of points that we should take care:

1- The solid conductors contains Joule losses, and also an active power transfered from the coil 1 to coil 2 and vis versa. Because the current in coil 1 will induce Eddy current in coil 2 and the same from coil 2 on 1. So to compute the impedance of Coil 1 and Coil 2, you should consider Active power in case you want to compare it for the total impedance seen from the source.

2- I suggest you to compute Z1 the impedance for Coil 1, Z2, the impedance for coil 2 and Z3 the impedance for capacitor. For each component, compute Active power and reactive power, and then compute the real part and imaginary part from them. Compute the equivalent Z and compare it to the one you have from the circuit. You should obtain the same thing.

Regards

Hello Farid,

Your solution matched with the Impedance seen by the source.

However, I did a new comparison and it is a bit confusing.

I simulated the same conductors, but without including any capacitor.

Then, I obtain the Z1 and Z2 of the solid conductors as you mentioned with active and reactive power.

After, I define Z3=1./(2*pi*Freq*1i*1e-5).

Finally, I obtain the total impedance as in the previous case:
Zan=((Z1.*Z3)./(Z1+Z3))+Z2;

In theory, I think both ways should match with each other isn't it? or There is a different current distribution that changes the behaviour of the solid conductors when adding the capacitor in FEM?

Thank you very much

Community-Pasted-Attachment-1649058780406.png

fzidat

Hello Yerai;

Can you first compare the impedance seen from the source to the one you computed from Z1 and Z2 ? Both in the case without the capacitor, did they match ?

Thanks

Yerai Moreno Lafuente

Hello Yerai;

Can you first compare the impedance seen from the source to the one you computed from Z1 and Z2 ? Both in the case without the capacitor, did they match ?

Thanks

Yes, the sum of Z1 and Z2 matches with the impedance seen by the source in the case without the capacitor.

fzidat

Yes, the sum of Z1 and Z2 matches with the impedance seen by the source in the case without the capacitor.

Thanks Yerai!

The current through the solid conductors in series is not the same with or without the capacitance.

Regards

Yerai Moreno Lafuente

Thanks Yerai!

So as you can see, adding Z3 without represente it in the circuit is not true, because the capacitance will add reactive energy that will have an impact on the two solid conductors. That's why you had these wrong results.

The current through the solid conductors in series is not the same with or without the capacitance.

Regards

Thank you very much.

Regards