Influence of magnet thickness and magnet orientation on the performance of IPMSM

The aim of this paper is to find a rotor design suitable for the interior permanent synchronous machine (IPMSM) with magnet poles in V- shape and to reduce the amount of magnet material. Because the cost of magnet material is high compared with the cost of the other materials used in electric motors, the design attributes that minimize the required amount of magnet material are important considerations in motor selection. The reduction of the magnet material results in a lower permanent magnet torque. This torque reduction has to be compensated by increasing the reluctance torque. Here, the mechanical robustness of the rotor has to be considered as one important boundary condition. For increasing of the reluctance torque, two crucial parameters are responsible: the inductance difference (Ld-Lq) and saliency ratio (Ld/Lq). Therefore, the criteria in the rotor design or the main target could be making these two parameters as large as possible.