Voltage Distribution Analysis of High dv/dt Fed Machines Using High Frequency Winding Model

Abstract

For the machines powered by SiC inverters, the high voltage variation rate (dv/dt) leads to uneven voltage distribution in windings, and affects the insulation service life. To predict the influence of SiC inverter steep voltage waveform on the voltage distribution, a high frequency transmission line model is studied in this paper. The capacitance and impedance parameters at different frequencies, which are used in the studied model, are simulated with finite element method considering the laminated structure of silicon steel sheets. Further more, the frequency domain characteristics of the winding impedance are derived with vector fitting method. Based on the studied model, using the simulated and derived parameters, time domain simulation is carried out to predict the voltage distribution in each turn of the coil, and compared with the experimental results.