Symbiosis Between Torque Ripple and Vibrations of Large Electrically Excited Synchronous Motor

Abstract

The electrical machine is subjected to different parasitic effects. In this paper, two parasitic effects; torque ripple and vibrations as well as the interdependence between them are discussed. It is almost impossible to have an ideal electrical machine which has constant torque or zero vibrations. The radial and tangential flux densities distribution in space and time and modulation of the different permeances on radial and tangential flux density distributions are responsible for vibrations and torque ripple in electrical machines. In general, both the parasitic effects are denoted from which reference part (stator or rotor) they are considered. This is because both are generated from the same sources (the resultant flux density). When the parasitic effect on torque is influenced then the vibration of the electrical machine is also influenced. Both the parasitic effects are systematically approached for the electrical excited synchronous machine as used in industry applications. Finally, in this study, the response analysis is performed to determine the gap between the parasitic torque and vibrations. It is shown that the large electrical machine with higher number of poles does have the vibration with 4-node mode.