Speed-Adaptive Full-Order Observer Revisited: Closed-Form Design for Induction Motor Drives

This paper deals with speed-adaptive full-order observer design for sensorless induction motor drives. The conventional full-order observer has been extensively investigated in the literature. Despite these efforts, the observer and its speed-adaptation mechanism are still not fully understood, and the tuning of the observer is often heuristic. Contrary to its reduced order variant, direct pole-placement design has not been available for the full-order observer. This paper revisits the full-order observer and presents a new closed-form observer design, where the observer poles can be directly placed with simple design parameters.