Design and Performance Analysis of Switched Reluctance Motor with Inner Holes to Reduce Radial Force

Radial force is known to be the major cause of vibration and acoustic noise in switched reluctance motors (SRMs). Radially placed holes in the rotor pole can significantly reduce the force, but it also lowers the torque. In this paper, the design of SRM with a set of holes distributed along the axial direction is proposed. The aim of the research is to reduce the radial force, which will lead to lower acoustic noise, while maintaining the torque. The effect of hole positioning to radial force and torque is examined with finite element analysis (FEA). The flux distribution change caused by the hole and the characteristics of the motor are examined. To verify the proposed structure, two rotor prototypes, with and without hole, are manufactured and tested. Vibrations and noise generated by the motor are measured with an accelerometer and a sound level meter. Both simulation and experiment results confirm the effectiveness of the proposed rotor design.