The doctoral dissertations of the former Helsinki University of Technology (TKK) and Aalto University Schools of Technology (CHEM, ELEC, ENG, SCI) published in electronic format are available in the electronic publications archive of Aalto University - Aaltodoc.
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Dissertation for the degree of Doctor of Science in Technology to be presented with due permission of the Faculty of Electronics, Communications and Automation for public examination and debate in Auditorium S4 at Helsinki University of Technology (Espoo, Finland) on the 18th of September, 2009, at 12 noon.
Overview in PDF format (ISBN 978-951-38-7349-3) [2623 KB]
VTT Publications 712, ISSN 1455-0849
Dissertation is also available in print (ISBN 978-951-38-7348-6)
Copyright © 2009 VTT Technical Research Centre of Finland
VTT Publications 712, ISSN 1235-0621
VTT-PUBS-712
TKK-DISS-2639
The main objective of this thesis is to develop new tools for model-based control of flexural rotor vibration in cage induction machines. In order to exert the control force on the rotor, a built-in force actuator based on self-bearing principle is considered. A low-order parametric electromechanical model coupling the eccentric-rotor machine, the actuator and rotor-dynamics is developed. Furthermore, numerical analysis of the actuator-rotor system is considered. The numerical analysis is based on time-discretised finite element analysis of the electromagnetic fields in the two-dimensional cross-section of the machine. The finite element analysis is used to estimate the parameters of the low-order model. The numerical analysis provides a tool for both designing the actuator and testing the control algorithms.
In the thesis, a control algorithm, previously used mainly in active magnetic bearings for compensation of harmonic disturbance forces, is applied by using the built-in force actuator. In the simulations, the control algorithm is embedded in the numerical analysis. The modelling and model-based control are verified by experiments. A 30 kW two-pole cage induction motor with an extended rotor shaft is used for measurements.
The results both from simulations and experiments show that, by using the built-in force actuator, the model-based controller is suitable for flexural rotor vibration suppression in a cage induction machine. In particular, the stable operation at the critical speed of the machine can be achieved by using the methodology presented in this research.
This thesis consists of an overview and of the following 5 publications:
Keywords: induction machine, electromagnetic actuator, rotor-dynamics, self-bearing machine, bearingless drive, mechanical vibration, active control
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© 2009 Helsinki University of Technology