Eddy current calculation by the finite element method using magnetic flux density directly as an unknown variable

This paper describes a new formulation of the two dimensional eddy current problem using magnetic flux density directly as an unknown variable and the results of some simple examples. To ensure the capability of the proposed method, some models with known theoretical solutions are analyzed. The error-evaluation is performed by comparing the results obtained by the proposed method with theoretical solution and traditional numerical method. It shows that the proposed method is very much useful in calculating magnetic flux density with high accuracy, but indicates comparatively some larger error than that of traditional method in the calculation of eddy currents. In fact, the error appears due to the differential operation of the calculated magnetic flux density. However, the magnitude of error in the calculated eddy current density by the proposed method is below 3 %. (author)