Verification of a full-order observer design for sensorless induction motor drives
Sähkötekniikan korkeakoulu | Master's thesis
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EST - Master’s Programme in Electrical Engineering
AbstractThe main topic of this thesis is the full-order flux observer as a part of the induction machine sensorless drives. First the induction machine inverse-Gamma model is presented with a brief overview of space vectors and different coordinate systems. Sensorless vector control principles and theory are presented next. Two very promising full-order observer designs were chosen, presented and tested through computer simulations. The simulations were implemented with the MATLAB/Simulink environment. The full-order observer designs are tried in different situations, like speed reversal, basic load tasks while running at a given speed, or a speed higher than the nominal to see how the design behaves. There is also a trial for stator resistance error, which can signify changes in the resistance due to temperature fluctuations or estimation errors from the mathematical model. From the test results it has been concluded that the original design is hard to tune, and it does not have tolerance to stator resistance changes. The improved design has brought more flexibility in terms of tuning, and there is a better tolerance for stator resistance changes.
Thesis advisorHinkkanen, Marko
flux estimation, full-order observer design, induction motor drives, sensorless vector control