Study on Orientation and Magnetization Characteristics of Injection-Molded IPMSM Using Sm-Fe-N Bonded Magnets

In this study, we analyze the injection molding and magnetization characteristics of an interior permanent magnet synchronous motor (IPMSM) using samarium-iron-nitrogen (Sm-Fe-N) bonded magnets and compare the experimental values of a prototyped rotor. First, a 2D finite element method (FEM) was employed to analyze the orientation during injection molding, confirming that the magnetic flux density exceeded the recommended value of 0.9 T. Next, a magnetization analysis was conducted to evaluate the distribution of magnetization rates. The results indicated a decrease in magnetization rates in the inner circumference of the rotor. In practical tests, we compared the measured back electromotive force (Back EMF) with the simulation results and demonstrated that the model considering magnetization analysis closely matched the measured values. Furthermore, torque characteristics were evaluated, confirming that considering orientation and magnetization analysis yielded characteristics closer to the experimental values. These findings demonstrate the feasibility of Sm-Fe-N bonded magnets for IPMSMs and the effectiveness of high-precision simulation models.