Acoustic Noise and Its Control in SRMs
Vibration and the resulting acoustic noise in switched reluctance machine (SRM) have generated intense interest from the time they became commercially competitive with dc and ac drives. This chapter outlines the causes of acoustic noise and some measures to overcome the problem. It must be noted that many laboratories claim to have produced SRM drives which are quieter than equivalent converter controlled induction motor drives. The chapter prvoides a basic description of noise sources in electrical machines in general and in particular SRM drive systems, noise cancellation or mitigation using the converter control, and qualitative design measures that could be implemented at the design stage of the SRM itself to reduce the noise. Many applications require a stringent upper limit on the acoustic noise of the motor drive, and most of the prototype development is iterated based on past knowledge and current practical work.