Optimal design to reduce torque ripple of IPM motor with radial based function meta-model considering design sensitivity analysis

In this study, optimum design process to reduce a torque ripple was presented for an interior permanent magnet (IPM) type electric traction motor. Firstly, 2-D electromagnetic finite element analysis was conducted to analyze the characteristics of the torque ripple in a view of magnetic saturation as well as cogging torque. Then, design factors of stator shape and rotor shape affecting to the torque ripple was selected as design variables. Secondly, using selected design variables, sensitivity analysis was performed to select design variable more affecting to the torque ripple and output torque by using design of experiments method. Thirdly, radial based function meta-model was constructed based on the results of the design of experiments (DOE). Finally, the optimum design was performed by using the constructed meta-model and method of feasible direction. By using the presented optimum design process, it is confirmed that the torque ripple of the optimum design was reduced to compare with the initial design and that output torque performance of the optimum design was maintained.