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Diplomarbeit 2004 (DA04): Arbeits-Archiv
 
DA Wil 04/1 - Maglev train (levitation & linear drive)
Studierende: Silvan Schafli, schaesil
  David Schneider, schnedav

Betreuer: Jurg Wild, wiju

Aim of this degree dissertation was to design a control for the maglev train present at the control technique laboratory as a model. There were two subtasks to consider: levitation and linear drive. First a stable levitation had to be reached for the carriage which, at the beginning of the task, had to be put into operation. The great stiffness reached through the new construction of the carriage resulted in a good levitation control. A two-stage control with a subordinate controller (Lead- or PDT1-controller) and a superposed controller (PI controller) was used. With four controllers at each corner abeyance was over-determined; a reduction to three superposed controllers solved this problem. An autonomous levitation control operated an implementation in a digital signal processor. One of the new problems was the aliasing which occurred when analog signals were digitalized. As there was no adequate compromise found between damping and loosing phase of the anti-aliasing-filter, there was no final solution for this problem found. The second part of the task consisted of the linear drive. For the PWM-Signal used to drive the inverter, three integrated circuits were used. We tried to convert a rotating model of a synchronous motor for the linear drive. The difference was detecting the position of the runner and calculating the stator field and with scalar control the conversion was easy to do. The position of the carriage could be measured using a laser sensor and the absolute number of wave lengths could be calculated. If the stator field is moved a quarter of a wave length towards the carriage, the maximum force exists. The force was in proportion to the current and could be set variably. The current loop was realised in xPC-Target using a PI-controller. Various control structures were tried. Using the observer of the state controller, the speed could also be adjusted.

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