Induction motor drive with intelligent controller and parameter adaption

A variable speed four-quadrant AC-motor drive using a robust and cost-effective induction machine with a current source inverter with gate turn-off thyristors (GTOs) was investigated. The essential advantage of this topology is the ability to produce currents and voltages in the machine with very low harmonic content in the whole operating range. Therefore, with this solution torque ripple, noise, and losses can be reduced considerably. However, the main problem of this topology results in the weakly damped resonant system consisting of the filter capacitors and the inductance of the machine. To stabilize this system and to attain a high dynamic and accurate behavior of the drive, a cascaded multi-input control system was designed. For robustness this control system is adapted to parameter changes of the mutual inductance (saturation) and the stator and rotor resistance (temperature), and an outline identification of the resistances is added. Furthermore, the influence of iron losses on the system is compensated