Sensorless control of induction machine with parameter adaptation

In this paper, a method for speed sensorless control of the induction machine is presented. The basic idea is to calculate the voltages induced by the main flux in the rotor field coordinates. This can be achieved by subtracting the stator voltage drops either in the stationary or in the field reference frame. The model´s main drawback is the poor stability in the braking region, where a stabilization algorithm has to be performed. Also, the influence of the stator and rotor resistances evaluation error on the speed estimation is analysed. Both parameters can be adapted using the direct component of the main flux induced voltage in the rotor coordinates.