Slotting effects and high frequency signal injection for induction machine rotor speed estimation

At zero frequency the speed sensorless operation may be only possible using high frequency signal injection methods (HFSIM´s). Using the HFSIM´s requiring the existence of saliencies in the machine. As the slots in induction machine present intrinsically design it is advantageous to exploit its effects for rotor speed monitoring. Injecting the HF voltage to fundamental supply, the rotor position can be determined by evaluating the current response. The combination between the model including slotting effects and the use of HF signal injection voltage to track rotor saliency created by slotting effects presents the aim of this research. Because the machine contains the rotor position dependent saliency, the carrier signal current includes the information about the rotor position. To extract this spatial information, the resulting stator current treads to heterodyning process to eliminate the disturbance components then the rotor speed is tracked by a closed-loop observer. The simulation tests will be achieved to verify the validity of the proposed model. At zero speed the effectiveness of speed estimation is confirmed through simulation results.