A new observer for speed sensorless field oriented control of an induction motor

Using adaptive Lyapunov design a new approach for the design of an observer for speed sensorless field oriented control is developed. The resulting scheme leads to a nonlinear full order observer for the motor states including the rotor speed. Assuming motor parameters known the design achieves stability with guaranteed region of attraction. Experiments on a real motor demonstrate high dynamic performance even at very low rotor speed and stability is extended to zero speed.