Hysteresis Motor: Transient-Time Model and Observer

The objective of this thesis is to analyze the dynamic behaviour of a hysteresis motor by means of a lumped-parameter model. With the development of such model, a flux observer for sensorless control of this machine is possible. Previous works in literature present an innovative model for the motor introducing a transient dynamic equivalent circuit and exploiting the state-space model for a field-oriented control. This work implements a model for a particular hysteresis machine prototype in MATLAB/Simulink. The model considers the equivalent circuit of the motor, adapted to the structure topology and material properties of a hysteresis motor for water pumping applications in automotive systems. The rotor material of this motor has been studied referring to previous works where the alloy has been previously described through the Jiles–Atherton model. In particular, experimental hysteresis loops were fitted by means of frequency dependent complex permeability properties. Integrating the electrical and the mechanical part of the model has been possible perform some open loop simulations, by varying the input condition, to better understand and evaluate the working point of the motor. In the second part of the thesis is presented the state-space model, used for designing an observer for the control of the hysteresis motor. At this point an analysis of the poles allow to stabilize and speed up the Luenberger observer gain matrix L, useful for estimate the magnetic flux direction. This procedure allows to use a field-oriented control approach and opens up to the possibilities to use this kind of motor in closed loop, thus giving new opportunities for further studies.