Interior Permanent Magnet Synchronous Machines With Composed T-Shaped Notching Rotor

Interior permanent magnet machines (IPMSMs) have attractive features, including high power density, high efficiency, and excellent control performance. However, the unsuppressed torque ripple of IPMSM will cause declined torque quality, increased vibration, and reduced reliability. This article presents a novel composed T-shaped notching rotor to suppress torque ripple for IPMSM. The mathematical models of cogging torque and winding factors considering T- shaped notches are established, respectively. Although the principle of the novel rotor design is clearly explained by mathematical models, the accurate dimensions of the composed T-shaped notch are difficult to calculate. Therefore, two-dimensional finite element analysis and multiobjective design optimization are employed to calculate the T-shaped notch dimensions. The electromagnetic performance of the proposed rotor machine is compared with that of the commonly notching rotor machine. In addition, the mechanical strength of the novel rotor is verified by calculations of stress and deformation. Finally, the proposed prototype with a novel rotor is fabricated, and extensive experiments are conducted. The results show that the torque ripple of IPMSM can be significantly reduced by the novel composed T-shaped notching rotor.