AC Induction Machine Speed Observer with Rotor Resistance Adaptation

Control of drives based on AC induction motors is a quite complex task. Provided the vector control algorithm is used we need to know not only the rotor speed but also the position of the magnetic flux inside the motor during the control process. In most applications the flux sensors are omitted and the magnetic flux phasor position has to be calculated. But there are also applications in which even speed sensors should be omitted. In such a situation, we have to solve the task of state reconstruction only from voltage and currents measurements. In the current paper, we present a method based on deterministic evaluation of measurement using the state observer based on Lyapunov function. The rotor resistance estimation is also discussed as it is one of main problems in AC induction machine speed estimation.