Quantification and analysis of acoustic noise in switched reluctance drives

Recent research has shown that the radial forces acting on the stator are responsible for exciting the resonant modes of the structure and this paper builds on this work by examining acoustic noise emissions in a low power 6/4 SRM drive operating under constant speed conditions. An attempt is made to quantify the acoustic noise levels in relation to the output power-speed characteristics via the use of empirical equations and a contour plot. Furthermore, the paper is concerned with the analysis of the mechanical stresses acting on the stator. Use is made of measured current waveforms and a time stepping technique whereby the stresses acting on the stator and resultant torque are calculated for a set of rotor positions. These results provide a key to develop new noise reduction techniques which are briefly discussed in the paper