Robust full-order observer design with less phase error for vector controlled induction motor

This paper proposes a novel design method of a robust full-order observer for a vector controlled induction motor. The full-order observer has been widely used to estimate rotor flux, but the guideline on its pole assignment for robust flux estimation against resistance deviations is still ambiguous. In this paper, the design problem is regarded as the phase specification of the relevant transfer function in consideration of phase error of the rotor flux estimation and it is solved by γ-positive real problem, gain scheduled H_∞ control and linear matrix inequality technique. Finally, several simulation and experimental results verify feasibility of the proposed method