Abstract During the operation of the motor and the transformer, the eddy currents are generated in the laminated iron core. To accurately predict the performance of the equipment, the demagnetization effects and related losses generated by the eddy currents, especially the abnormal eddy current loss, must be effectively calculated. However, the existing eddy current field calculation methods, based on either the magnetic domain and domain wall motion models or the hysteresis models, are too complex and difficult to be integrated into numerical calculations. Based on the concept of abnormal eddy current loss factor and combined with the previous research work, this paper proposed an anisotropic equivalent conductivity correction model for laminated cores. By theoretically analyzing the eddy current field and deducing and comparing the total eddy current loss equations, the rationality of the proposed equivalent conductivity correction model was proved in theory. By fabricating a typical iron core model wound with the oriented silicon steel sheets, and conducting the experimental measurement and three- dimensional finite element eddy current field calculation, it was revealed that the actual core eddy demagnetization effect is far more than the traditional eddy current field calculation method considering only the classical eddy currents. As a result, the feasibility and effectiveness of the equivalent conductivity correction model and the related eddy current field analysis method proposed in this paper were further verified by comparing the measured magnetic density and iron loss values and the calculated ones under various excitation conditions.
Received: 03 September 2019
Published: 24 July 2020