Rotor position control for induction machines using diametrical inversion of stator voltage

To xciirately solvc the speed or rotor position control problem of an induction motor (IM), the key has been R proper design of a torquc controllcr included in ai cascaded control structure. The IM dynamic behaviour presents a notiliticar coupling bctwccii the flux and the torque and 50 ttlc &coupling has been the first task, as iii field-oricntcd control and direct torque control, whcrc some feedback signals are obtained using observers. A iccciil 1M cominand action, the dianictricrll inversion, whose implementation is easy and givw good rcsulk, uscs the sliding mode. A mechanical first order switching liinclion dctcrrniiics the successike applicaition of 1M stator voltage diametricd inversions. A torcpc conlrollcr is no1 nccdetl, thc sliding mode robustness elirninatcs thc dccoupIing problem, and the fast ioversion or thc clcctioinagnctic torque ;illows ii rotor positioning faskr than a torque controlled sccond ordcr system. Soiiic siniulstion and experimental results show tlic position responses and cxliibit tlic syslcm robiisimss to cxtei-nal disturbances arid winding rcsistanm mriations with teniperaturc.