Bertotti Modified Excel

Andoni Garcia

Hi everybody.

 

I'm simulating a FeSi transformer core for calculating iron losses. In this regard, I'm using the Bertotti modified coeficients whose parameters are obtained from the Bertotti Modified (Flux's folder) excel worksheet .

Alright up here.

 

The problem arises when I have to use the solver on the worksheet: I would like to know what are the input parameters (k1 k2 k3 a1 a2 a3), because the result will be different according to those numbers.

 

Thanks lot.

 

Alejandro Rodríguez

Hello Andoni,

 

In fact, from the point of view of the excel file these parameters are not inputs but outputs. Their initial values are just an initial point in order to launch the optimization process managed by excel.

On the other hand, from Flux point of view, you can find their meaning in page 7 in the document 'ComputationIronLosses.pdf' I have sent you some weeks ago.

Please, take into account that for the same losses inputs (usually taken from material datasheet) you can find different set of parameters that fit well with the losses curve of the material. The set of parameters you will obtained will depend mainly on the initial point (i.e., the initial values of k1, k2, k3 and a1, a2, a3).

Sometimes is useful to play with these initial point to find the best set of Berttoti’s coefficients. It is also frequent that you want to fix some parameters (tipically the three exponents a1, a2 and a3) you can do so excluding these exponents from the excel. Additionally, you can established maximum and minimum value for these parameters during the fitting process.

Please, find attached a .pdf which explains the meaning of these coefficients and their calculus process in the excel file (DetermineBertottiCoefficientsForIronLossesComputation.pdf)

Hope this helps.

Best regards.

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