High-frequency stator-to-frame admittance modeling for AC machine by using Debye model

This paper proposes an improved high-frequency equivalent model of ac machine, focusing on the accurate extraction of stator-to-frame capacitance. The behavior that the capacitance decreases in several stages throughout the observed frequency is analyzed and modeled by applying Debye model. To verify the constructed equivalent model, the input and transfer impedances of a phase line is compared with measurement. The newly developed per-unit-length equivalent model with the improved admittance model can be used to estimate the high-frequency behavior of ac motor accurately.