Prediction of the Voltage Distribution in a Inverter-Fed Hairpin Stator Winding

This article describes a method to predict the voltage distribution in the stator winding of an electrical machine with profile conductors (hairpins). The method allows the identification of spots with high potential differences where high stresses in the insulation system occur. It can be used in the design phase of the machine to design a specific insulation system or to insulate the conductors with high differential potential individually. The parasitic and partially frequency-dependent parameters used in the method are based on the geometric parameters of the winding i.e. on its conductor dimensions, winding layout and their materials. They are subsequently combined into a distributed equivalent circuit network. The resulting network is solved in the frequency domain using a modified nodal analysis. An ideal or measured input voltage pulse is applied to the system and the transient nonlinear electric potentials of the individual conductors are determined, yielding responses as function of time.