A robust adaptive sensorless field-oriented control using a modified stator flux observer

A sensorless vector control scheme is proposed based on a reduced order dynamic model of an induction motor and an adaptive parameter identification technique. A very special feature of this work is the fact that the observer dynamics and the adaptive algorithm are solved concurrently via the Runge-Kutta 4th order method in the hardware environments. This approach improves the numerical stability of the proposed control scheme over whole speed range. Another characteristic feature is that it avoids the use of the problematic pure integrator in the stator flux observer. To overcome the pure integrator problem, the authors modified the stator flux observer so that the poles lie in the left half complex plane. Experimental results show that the proposed sensorless control scheme yields fairly good dynamic and steady-state performances irrespective of applied load torque