Power-range extension of an induction motor speed-drive by using a three-level GTO inverter with space vector modulation

The authors make use of a field oriented control for high-power induction motor drives with Kalman filter flux observation. Such a control structure, associated with a two-level GTO inverter, allows to supply asynchronous drives up to 900 kVA. In order to extend the power range for the use of this control, the authors have utilized a three-level GTO inverter. The space vector modulation method is chosen to obtain a better quality of electromagnetic torque and stator current of the induction motor. Precise simulations show the improvement obtained in comparison to a three-level GTO inverter with sinusoidal pulse-width modulation. The performances of the speed drive have been tested at transient as well as steady-state operation. The behaviour of the complete speed drive system has been studied carefully in all four quadrants of the torque-speed plan