Analytical representation and characteristics optimization for radial electromagnetic force of the switched reluctance motor under airgap eccentricity

Aiming at the influence of radial electromagnetic force on vibration and noise of the switched reluctance motor (SRM), the radial electromagnetic force under airgap eccentricity is represented based on the virtual displacement principle and Maxwell stress tensor. Multi-objective optimization of motor electromagnetic characteristics including magnetostatic torque, radial electromagnetic force fluctuation, and unbalanced radial force amplitude is completed. First, the analytical representation for the radial electromagnetic force is obtained by the virtual displacement principle, and the expression of the unbalanced radial force caused by airgap eccentricity is deduced. Then, the spatial distribution of the radial electromagnetic force is modeled by the Maxwell stress tensor, which makes the radial electromagnetic force characterization more comprehensive. In order to improve the electromagnetic characteristics of the SRM under airgap eccentricity, sensitivity analysis and multi-objective optimization are carried out to obtain the optimal solution set of the motor structure parameters. The simulation results show that the radial electromagnetic force fluctuation and the unbalanced radial force amplitude decreases by 64.09% and 23.05%, respectively, when the magnetostatic torque is sacrificed by 6.36%, which provides a framework for multi-objective optimization of motor structure parameters.