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Magistrsko delo se poglablja v problematiko merjenja pozicije gredi električnega stroja. Na podjetju Mahle se je pojavila potreba po razvoju novega električnega stroja za dvokolesnike, katerega gred je prosta na obeh straneh stroja. Na dodatni prosti strani gredi bi bila mogoča montaža elektromagnetne zavore. Obstoječ merilnik pozicije gredi, ki je v podjetju široko uporabljen, je postavljen na konec gredi zato je bilo potrebno začeti z razvojem novega merilnika, ki bi omogočal oba konca gredi električnega stroja prosta. Ideja novega merilnika prav tako izkorišča magnetni princip merjenja a za razliko od obstoječega merilnika je ta zgrajen iz magnetnega obroča pritrjenega na gred in senzorskega dela, ki meri magnetno polje iz strani gredi. Delo se predvsem osredotoča na možne neidealnosti obravnavanega merilnika z magnetnim obročem, ki se pojavijo pri proizvodnji in montaži merilnika na električni stroj. V ta namen je izdelan model magnetnega obroča in senzorja s katerim so posamezne neidealnosti simulirane z metodo končnih elementov. To omogoča enostavni vpogled in diagnostiko napak, ki se pojavijo pri merjenju mehanskega kota na realni napravi. Dodatna uporabna vrednost modela je uporaba le tega za načrtovanje merilnika pozicije gredi z magnetnim obročem. S pomočjo tega se lahko določi natančne dimenzije magnetnega obroča in postavitev senzorskega dela merilnika v njegovi okolici. Za konec so na realni napravi opravljene tudi meritve z obravnavanim merilnikom, analiza izmerjene napake mehanskega kota in primerjava z obstoječim merilnikom na koncu gredi. This master thesis deals with the magnetic field-based measurement procedure of the electric motor rotor position. The main objective was to study, analyze and select an appropriate rotor/shaft position sensor for a new electric motor being developed for a two-wheeler whose shaft needs to be is free on both sides, since an electromagnetic brake should be mounted on the shaft. The existing rotor position sensor, which has been used so far, was positioned on the shaft end, therefore it was necessary to develop a new shaft position sensor that would allow both shaft sides of the electric motor to be free and consists of a magnetic ring attached to the shaft and a sensor that measures the magnetic flux density. For this purpose, a 3D numerical model based on finite element method of a magnetic ring and a sensor was built. Based on the numerical simulations the appropriate dimensions of the magnetic ring and the location of the sensor have been determined and the possible errors which may occur during the manufacturing and installation of the sensor have been studied and analyzed. The obtained results enable an easy insight into the sensor nonlinearities and the diagnosis of errors that may occur when measuring the mechanical angle on a real machine. Finally, the measurements on a real electrical motor with permanent magnets on the rotor have been performed with two different rotor position sensors in order to evaluate the error of the mechanical angle and thus the rotor position measurement. |
