ACOUSTIC NOISE ANALYSIS OF HIGH SPEED SRMS BY ELECTROMAGNETIC FORCES

This paper presents a simple procedure for acoustic noise reduction in switched reluctance motor (SRMs). Radial forces between rotor and stator teeth cause a vibration of stator laminations and windings. The vibrations lead to acoustic noise. The radial forces can be determined by the two-dimensional finite element method (FEM). The magnitude of the acoustic noise at any operating speed is calculated by an analytical mode which depends on the radial forces and circumferential deflection. The calculation, simulation and measurement results are useful to improve stator and rotor poles with acoustic noise reduction. Moreover, it is important for the SRM to avoid the mechanical resonant frequency. If the electric frequency equals mechanical resonant frequency, the vibration and acoustic noise is extremely high and destroys the mechanical structure of the high speed motor.