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Iron loss prediction in high‐speed permanent‐magnet machines using loss model with variable coefficients

Iron loss prediction is extremely crucial to performance and thermal analysis for high-speed permanent-magnet (PM) machines, but it is difficult to conduct at arbitrary frequency especially high frequency. Due to the frequency-dependent coefficients of iron loss model, although iron loss can be calculated by loss model with constant coefficients under fixed frequencies, it is not feasible to measure the required loss data of non-oriented electrical steel under each frequency. Moreover, toroid tester is better to obtain accurate loss data of steel, but the data under specific high frequency cannot be directly measured due to the limitation of equipment and tester. Thus, this study presents a three-term iron loss model with variable coefficients to predict iron loss of machines at arbitrary frequency, especially high frequency based on measured loss data of steel at low frequency. Although both proposed three-term model and conventional two-term model with variable coefficients can predict iron loss of machines at an arbitrary frequency, the comparison shows that the accuracy of the three-term model is higher. In addition, experiments validate that proposed three-term model with variable coefficients is accurate and feasible for iron loss prediction in high-speed PM machines.