Core Loss Coefficient Extraction from Multi-Frequency Loss Curves
The principles of the computation algorithm for Kh, Kc, Ke, and Y are summarized below.
The iron-core loss without DC flux bias is expressed as the following:
where f is the frequency and Bm is the amplitude of the applied sinusoidal flux density waveform. The coefficients Kh, Kc, and Ke, as well as Y, can be derived by minimizing the error between the measured and modeled core loss curves at different frequencies f and varied flux density amplitudes Bm expressed as
where Pmij and Pvij are the measured and modeled core losses at different frequencies fj and varied flux density amplitudes Bmi, n is the number of points of the measured core loss curve, and m is the number of curves of different frequencies.
The modeled core loss Pvij depends on unknown parameters Kh, Kc, Ke, and Y. Here Kh, Kc, and Ke can be identified by linear regression, and Y by a numerical optimization algorithm. Assuming an initial value of Y, the error can be expressed as
After Kh, Kc, and Ke have been determined by linear regression, the error is a function of Y. The optimal Y can be finally derived by applying a numerical optimization algorithm to minimize the error.
Related Topics
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Calculating Properties for Core Loss BP Curve
Core Loss Coefficient Extraction from Single-Frequency Loss Curve
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