Impedance saliency detection for sensorless control of AC machines utilizing existing PWM switching harmonics

The following paper describes the basic idea of making use of high frequency signals, present in a PWM inverter drive system, for analyzing the machine impendence saliency. The proposed method focuses particular on the extraction of rotor bar spatial salience modulation. The final target is to use this information in order to reconstruct the mechanical rotor position. No additional signal injection is applied, only the inherent present high frequency signals (PWM carrier harmonics) were used.