Optimization of Hairpin Winding Schemes with Respect to the Common-Mode Current

With the increasing use of fast-switching power electronics, high-frequency behavior is becoming increasingly im-portant in electric power drive systems. This importance is raised further by the increasing use of hairpin windings in automated winding processes due to their high capacitive coupling to the stator core. As a result of the high frequencies, an undesirable parasitic common-mode current results. In the design process for a hairpin winding, this parasitic current can be reduced by using the shifting method. Furthermore, this method can be used for elaborating design rules for hairpin windings. Therefore, this paper deals with the influence of shifting the winding terminals on the common-mode current and the derivation of such design rules. To this end, the calculation method for the common-mode current is validated by a laboratory measurement on an existing stator sample. Lastly, the design rules are analyzed for their general validity, taking into account different voltage signals and winding schemes from the shiftina algorithm.