Rotor speed estimation of doubly fed induction motor using high frequency carrier signal injection

This paper presents a rotor position estimator for doubly fed induction motor (DFIM) based on carrier signal injection. The proposed control uses a high frequency signal injection methods to estimate the speed of doubly fed induction motor, which is used as feedback of vector control algorithm. This method is based on superimposed with the voltage stator a high frequency signal. The resulting voltage is applied in the stator windings using a pulse width modulated voltage-source inverter. The injection of these signal induced a rotor high frequency current, which contains the rotor position information, from which the rotor speed is estimated. In order to implement this estimator, a sensorless control structure based on stator field oriented control is investigated in which two voltage inverters are used to supply the stator and rotor sides. The simulation results implemented on Matlab/Simulink shows effectiveness under various operating conditions (Low speed, nominal speed and high speed).