Reducing the Losses of Electrical Machines under Torsional Vibration

Abstract

Electric drivetrains have an almost rigid-body torsional vibration mode at a low natural frequency. If a torsional excitation occurs close to this frequency, the vibration amplitude may grow large, and the losses of the electrical machine may significantly increase. The possibilities to reduce or eliminate these additional losses are studied. When the machine is connected directly to the grid, the possibilities for vibration control mainly come from mechanical solutions. If the machine is fed from a frequency converter, there are several potential ways to suppress the additional losses. The torsional vibration control of electric drivetrains is studied from loss minimization point of view. This is the novelty of the paper.