Impedance Modeling Oriented Toward the Early Prediction of High-Frequency Response for Permanent Magnet Synchronous Machines

Abstract

This paper presents and validates a method for early estimation of the high-frequency impedance response for a real Permanent Magnet Synchronous Machine (PMSM). The main contribution of this work lays on the simplicity of the data required to tackle the prediction, which do not require any experimental tuning or 3D simulations. The required inputs for the method are the 2D cross-section of the machine and the material characteristics of the conductors, insulation and iron laminations. An approach using the Finite Element Method (FEM) coupled with a circuit simulator is utilized to obtain the machine common-mode and differential-mode impedances over a broad frequency range. Experimental measurements are performed up to the resonance band to validate the methodology. In addition, the influence of the machine rotor and housing on the impedance curves is experimentally assessed. A machine with concentrated winding is used as a case study machine to test the model.

A Review of Broadband Frequency Techniques for Insulation Monitoring and Diagnosis in Rotating Electrical Machines

“…The electromagnetic coils can be physically described in detail by utilizing multi-conductor transmission line theory [10]. The single conductors within the machine slots and forming the end-winding are represented by lumped-pi equivalent circuits by assuming that the conductors are electrically short [11]. These circuits are described by per unit length parameters (i.e., series resistance and inductance, and shunt capacitance and conductance).…”

“…Moreover, high-frequency eddy-currents flowing within single laminations cause a shielding effect of the main flux within the slots, which dramatically affects the series inductance and resistance [14]. The mutual resistance and inductance (i.e., R ij and L ij ) represent the losses and flux linkage induced by the current flowing within neighbouring conductors [11]. The shunt capacitance and conductance (i.e., C ii and G ii ) represent the storage of electric field, and current conduction and the dielectric losses of the groundwall insulation respectively.…”

AC motor impedance predictive modeling methodology taking into account windings variability

“…However, results presented in [16] have significant damping due to coupled real impedances but do not use any dielectric losses. Both authors in [14] and [23] noted a significant difference between their models and impedance measurements in particular on damping. No conclusion can be drawn to this question in the current study and further work is needed to conclude on the need to combine those aspects as no dielectric losses were taken into account in this paper.…”

Sensitivity Analysis of a Numerical High-Frequency Impedance Model for Rotating Electrical Machines

“…A general script interfaces the FEM obtained parameters with the SPICE software and extracts the input impedance of the circuit. Further details about the modelling method are presented in [14]- [16].…”

“…For the Common-mode (CM) impedance, the connection is made between the machine housing and the three phases in shortcircuit. Figure 4 shows the comparison between experimental and simulation results presented in [16].…”