Mechanical Engineering Journal
Online ISSN : 2187-9745
ISSN-L : 2187-9745
Special issue on Advances in Magnetic Bearing Technology
Compensation of unbalance forces of a switched reluctance machine by separate control of phase currents
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2015 Volume 2 Issue 4 Pages 15-00042


The presented work handles the compensation of unbalance forces for a 6/4-Switched Reluctance Machine (SRM), which generate significant radial magnetic forces in an eccentric motor shaft position. When the rotor is operating e.g. in its principal axis of inertia, these forces must be compensated by the bearings. This is of major interest for magnetically levitated long term storage flywheels where bearing efficiency is a key factor for the overall system performance. To minimize magnetic pull, the two opposing coils are controlled separately instead of a common serial connection. Three different methods to compensate unbalance forces are presented: The modification of the reference current of the opposing coils, a quasi-parallel connection and a combination of a current controller and a fluxlinkage controller. For the observation of fluxlinkage two different approaches are described. These methods are compared to each other by means of simulation. Due to the back electromotive force (BEMF) in high speed operation, precise current control is a major challenge. Hence the third method is leading to the best results, so it was also implemented on a test rig for validation of the simulation results.

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© 2015 The Japan Society of Mechanical Engineers
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