Design and control of a permanent magnet bearingless machine
Jaatinen, Pekko (2019-11-29)
Väitöskirja
29.11.2019
Lappeenranta-Lahti University of Technology LUT
Acta Universitatis Lappeenrantaensis
School of Energy Systems
School of Energy Systems, Sähkötekniikka
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In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Lappeenranta-Lahti University of Technology LUT's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_ standards/publications/rights/rights_ link.html to learn how to obtain a License from RightsLink.
Julkaisun pysyvä osoite on
https://urn.fi/URN:ISBN:978-952-335-443-2
https://urn.fi/URN:ISBN:978-952-335-443-2
Tiivistelmä
The overall efficiency of high-speed applications can be improved by applying direct drive motor technology. Operating in the high-speed region is a demanding task for the traditional bearing technology. With active magnetic bearings, the rotor can be supported by the magnetic force. As the shaft is rotating in the air, polluting oil lubrication is not needed, and in practice, the rotor system is maintenance free. However, the magnetic bearing construction increases the rotor length, which has an adverse effect on the dynamical behavior of the rotor. Bearingless motor technology combines the levitating force capability of the magnetic bearing with the traditional electrical motor. This integrated structure enables a shorter machine length than with the active magnetic bearings.
Compared with the traditional electrical machine design flow, additional parameters must be taken into account when incorporating the bearingless feature into a motor system. It is important to analyze the interaction of the generated torque and the levitating force. The main objective is to minimize this interaction so that the control of the bearingless machine is more straightforward. The rotor controlled by bearingless motors constitutes a multi-input multi-output system. The system includes cross-couplings between the rotor and the motor units. This issue must be taken account in the control of the bearingless machine.
This doctoral dissertation addresses issues related to the design of a bearingless machine. The main focus is on how to minimize the interaction between torque and levitation force generation. A model-based control approach is adopted to control the bearingless machine by taking into account the cross-couplings. The model is validated by a system identification approach, and the controllers are tested experimentally in the bearingless machine.
Compared with the traditional electrical machine design flow, additional parameters must be taken into account when incorporating the bearingless feature into a motor system. It is important to analyze the interaction of the generated torque and the levitating force. The main objective is to minimize this interaction so that the control of the bearingless machine is more straightforward. The rotor controlled by bearingless motors constitutes a multi-input multi-output system. The system includes cross-couplings between the rotor and the motor units. This issue must be taken account in the control of the bearingless machine.
This doctoral dissertation addresses issues related to the design of a bearingless machine. The main focus is on how to minimize the interaction between torque and levitation force generation. A model-based control approach is adopted to control the bearingless machine by taking into account the cross-couplings. The model is validated by a system identification approach, and the controllers are tested experimentally in the bearingless machine.
Kokoelmat
- Väitöskirjat [1072]