Andreas C. Koenig

Calculation of eddy current losses in conductive sleeves of synchronous machines

In this paper, analytical and finite element method (FEM) approaches to calculation of eddy current losses in conductive non-magnetic sleeves (cans) of synchronous or induction machines are presented. Those losses are especially important in high speed electrical machines as the sleeve losses are a function of the second power of rotational speed. In some applications, non-conductive sleeves, e.g. carbon graphite cannot be used due to problems with thermal compatibility of rotor and stator materials.

A PI-based control strategy for mitigation of torque harmonics in switched reluctance motor drives

An issue that often arises in switched reluctance machine (SRM) drives is excessive vibration/noise created by harmonics of electromagnetic torque (torque ripple). In this research, analytical techniques are used to map vibration harmonics to stator current magnitudes and phase angles. The map is used to formulate a proportional plus integral (PI) control that adjusts current amplitude and phase in response to measured vibration. Simulation and hardware results are presented that demonstrate the effectiveness of the proposed methods.