Multi-Objective Design of an Interior Permanent Magnet Machine with Robustness Considerations

In this paper, a modular cascade interior permanent magnet machine for electric vehicle applications is investigated by using multi-objective differential evolution algorithm and 6σ robust design method. The efficiency, average torque and cost of interior permanent magnet machine are selected as objectives to find the optimization parameter combination, and finite element analysis is carried out by using open source software FEMM during the electromagnetic performance optimization. In order to accelerate the computation speed, an efficient optimization approach is proposed during the robust design process. In addition, after the electromagnetic specifications are obtained with the optimization machine structure, a lumped parameter thermal network model of interior permanent magnet machine is further developed to analyze the thermal performance. The effectiveness of lumped parameter thermal network model is validated by comparing the results with those of commercial software MotorCAD. According to the results, it is seen that the proposed interior permanent magnet machine is of good electromagnetic characteristics and thermal performance, which can be used in electric vehicle applications.