Eddy-Current Magnetic Field Effects in the Switched Reluctance Motor

This paper mainly studies and calculates the eddy-current loss in the switched reluctance motor (SRM). Since the eddy-current loss is as a result of the magnetic fields generated by the induced current in the conductors, it is essential to study the change of the magnetic fields in SRM. Firstly, by using the two-dimensional (2D) magnetic equivalent circuit (MEC) method, the mathematical expression of the average magnetic flux of each part of the 6/4 SRM prototype is obtained. Since the magnetic flux waveforms are non-sinusoidal and non-linear, the Fourier transformation method is applied to decompose them to a series of various frequencies sine magnetic flux waveforms. Moreover, the Bertotti's separation model and the eddy-current correction factor are both adopted to calculate the eddy-current loss. The 2D and 3D finite element (FE) model of the prototype are both established to analyze and calculate the magnetic flux waveforms and eddy-current loss at different speed. Finally, the MEC and FE method calculation results are compared, which verifies the correctness of the proposed method.