In this paper, an adequate B-H curve extrapolation method is proposed and its reliability is verified through experiments. A method is developed to estimate the magnetic saturation induction from the density of the lamination core and electrical resistivity. The magnetic saturation induction of electrical steels measured using a vibration sample magnetometer are compared with the analytical results to validate the accuracy of the proposed estimation method. It is found that the predicted error in the magnetic saturation induction of the electrical steels are approximately 1.2% when the proposed method is used. The performance of interior permanent magnet synchronous motors that applies the proposed method are evaluated via 2D nonlinear finite element analysis and through experiments. Based on the obtained results, the extrapolated B-H curves from the estimated saturation induction can be used for various analyses in saturation region.

This paper deals with the weight reduction design of In-Wheel type motor for high power density.Accordingly, characteristic and weight of the motor caused by modifying reduction gear ratio are examined.Weight of motor is minimized by modulating the ratio of stack length and external diameter of stator. Then, In-Wheel motor geometry based on the prototype is optimized to get the determined parameters using response surface methodology (RSM) and Finite Element Method (FEM). Optimal design of core usage in rotor is conducted for minimizing weight of motor which has identical characteristic to the prototype.Characteristic analysis is conducted by using equivalent circuit analysis of PM type motor. Through the presented weight of In-Wheel type motor, total weight is reduced to 25%, and power density is improved to 57% from the prototype motor.