A stand-still method for estimating the rotor resistance of induction motors

A method to identify the rotor resistance of induction motors at stand-still using only a standard voltage source inverter (VSI) as both the actuator and measuring device is described. The method takes the inverter nonlinearity into account and considers the skin effect of the rotor windings. The estimation scheme controls the VSI in such a manner that no rotational shaft torque is produced, which promises for a user-friendly service during the commissioning of a drive-motor system, regardless of the mechanical load.