Simulation of cable and winding response to steep-fronted voltage waves

The detrimental effect of steep-fronted voltage waves impinging on machine windings has become a subject of concern with the advent of fast switching IGBT inverters. A simulation model using finite difference techniques has been developed which predicts observed phenomena such as machine terminal overvoltage transients and nonuniform voltage distribution within these windings. This analysis tool, unlike previous methods discussed under the background survey section of the paper, includes the feeder cable as part of the simulation to reveal the effect of its characteristic impedance and length upon the temporal machine winding voltage distribution. Simulation results are compared to actual measurements. The use of this tool in inverter waveshaping, cable selection and winding design is briefly considered.