PERFORMANCE ANALYSIS OF A CLOSED-LOOP FIELD-ORIENTED CAGE INDUCTION-MOTOR DRIVE

This paper presents the analysis of the dynamic performance of a close d-loop hysteresis current controlled voltage source inverter (VSI) fed cage induction motor drive. The control scheme employs the principle of field orientation which is also known as the vector control. This e ssentially transforms the dynamic structure of the induction motor int o that of a separately excited DC motor. The induction motor drive is modelled and simulated with a view to studying its dynamic behaviour i n the closed loop. The dynamic response of the system for conditions s uch as starting, speed reversal and load perturbations has been invest igated in detail. The speed loop with IP (integral plus proportional) controller maintains the desired level of speed irrespective of the lo ad variation to which the machine is subjected. The design aspects of the IP based speed controller are also discussed. Simulated results sh owing the behaviour of the cage motor drive in field coordinates are g iven to demonstrate the effectiveness of this type of control.