Dynamic model of induction machine with faulty rotor in field reference frame

This paper presents a control model of squirrel cage induction machine with broken rotor bars. The basis for model´s equations is the fact that this type of faults inevitably alters the rotor parameters. Both the resistance and inductance take a sinusoidal shape, being a function of rotor angle, almost regardless of the configuration of fault. Differing from previous work, in this paper a model has been developed in rotor field coordinates, being this the preferable reference frame for machine control and thus easier for control engineers to grasp, especially in closed-looped systems. The approach has been tested on laboratory models of two different induction machines connected to the grid with completely different severities of faults. The results show a very good agreement between measurements and simulations.