Study of Precise Computation Method of Magnetic Loss Considering Blanking Press Strain

Abstract

Mass productions of the motor core such as the blanking of the electromagnetic steel sheet and the shrink fit cause the residual strain in the material, processing strain, which prevents the movement of magnetic walls and increases the magnetic loss in the motor. Conventionally, the increase of the magnetic loss by the processing stress was evaluated with trial products, because it couldn't be done in the design phase. So, it was difficult to optimize the motor design considering the processing stress. Therefore, this paper studies the computing method of the magnetic loss considering the blanking press strain which is particularly estimated to be large influence on the magnetic loss as follows:

1: The magnetic flux density of each part in the motor is calculated by the two-dimensional static electromagnetic field analysis with the initial magnetization curve according to the distribution of the blanking press strain.

2: The magnetic loss is calculated by the one-dimensional dynamic electromagnetic field analysis with the hysteresis curve according to the blanking press strain and the boundary condition based on the two- dimensional magnetic flux density.

We think that it is effective in computing magnetic loss considering stress by blanking, because result of this approach agrees well with experimental trend.