| Zusammenfassung: |
For modelling, analysis and optimization of bearingless drives as well as magnetic bearings an accurate calculation method of the bearing forces and the motor torque is of significant importance. The dynamic model can be derived using the vectorial representation of the magnetic field using the Maxwell Stress Tensor. In this paper a certain, but significant type of bearingless systems is considered. In particular, it focuses on bearingless arrangements where the radial forces and torque are actively generated by the stator currents, whereas the axial position as well as tilting are passively stabilized utilizing magnetic reluctance forces or axial bearings. Thereby, possibly present cogging torque and radial forces caused by reluctance might be compensated by controlling the stator currents. However, for most applications constructive means are applied to minimize these phenomena. Thus, this paper presents a novel approach to take cogging torque and reluctance forces into account. The decomposition of the magnetic field into its Fourier coefficients allows a quite simple and elementary description of the obtained equations. Hence, a deep insight into the force respectively torque generation of bearingless systems is given. |
