Stator core shape design for low core loss and high power density of a small SPM motor

In this paper, a stator core shape design method is proposed for an improvement in power density of a small surface-mounted permanent magnet (SPM) motor. In order to improve power density of a motor, it is necessary to increase torque of a motor or to reduce weight of a motor. However, when a stator core shape is miniaturized to reduce weight of motor, winding regions in a motor frequently decrease. Our stator core shape design method improves power density of a motor by reducing weight of a motor without decreasing torque and keeping winding regions constant. Moreover, core loss of a motor decreases by using our method. A Bezier curve is used for determination of a stator core shape. The finite element method in consideration of the vector magnetic properties is used to evaluate iron loss of the motor shaped by our method. As a result, power density of a SPM motor is improved, and core loss of the motor decreases.