Skin Effect of Squirrel Cage Induction Motor under High-Frequency Signal Injection

This paper proposes an analysis of the skin effect in squirrel cage induction motor under high-frequency signal injection. The high-frequency signal is usually injected for sensorless control and parameter identification. Since both of them require the accurate identification of impedance characteristics, the skin effect under the injected signal should be analyzed in detail. Meanwhile, the rotor bar is much thicker than the stator conductor, so it is severely affected by the skin effect at the frequency of the injected signal. Thus, the proposed analysis focuses on the skin effect on the rotor bar at high-frequency. The proposed analysis is entirely based on the finite element analysis, and it considers the practical operating condition of the induction machine, driven by the field oriented control. The variation of high-frequency rotor resistance and inductance according to the injected frequency and current for the torque has been represented by finite element analysis.