Strategy for Predictive Modeling of the Common-Mode Impedance of the Stator Coils in AC Machines

This paper presents a methodology for the predictive modeling of common-mode (CM) impedance of the stator windings of AC three-phase machines taking into consideration all the parasitic inductive and capacitive phenomena. An electrical model with lumped parameters (RLC) is generated, based on a physical approach of the machine, which is implantable in a SPICE-type software. The prediction results are in satisfactory agreement with the measurements ones on a large frequency bandwidth [10 kHz to 100 MHz]: The low-frequency capacitance is predicted with better than 5% accuracy, while the peaks and dips in the CM impedance plot are very well predicted beyond 5 MHz.