A New Sensorless Control of Induction Machine Using a Rotating High Frequency Voltage Injection Based on Rotor Slotting Saliency

Sensorless control based on high frequency signal injection methods (HFSIM's) represent the interesting way to provide the high performances of the AC drives at low or near zero speed range. The HFSIM's exploit the machine saliency property which contains the information about the rotor position or flux position and track it by injecting a high frequency excitation. In this paper, a novel sensorless control strategy with the injection of a high-frequency rotating sinusoidal voltage into a stationary reference frame for an induction machine (IM) is proposed. First, the present paper exposes a model of the induction machine including slotting effects which it can be exploited in order to extract the harmonic saliency created by rotor slotting. Second, the high frequency signal injection method is used in order to allow tracking the characteristic harmonic saliency due to rotor slotting from which the rotor position and speed may be estimated. A High frequency voltage signal injection creates a high frequency current modulated by the saliencies presented inside the machine. To extract information about rotor position, the resulting stator current treads to heterodyning process to eliminate the disturbance components and subsequently the rotor position may be extracted by a closed-loop observer. Simulation results are shown in order to verify the validity of the proposal and to confirm the effectiveness of estimation method at zero frequency.