Extension of slot-opening-embedded electrostatic shields in the region of the end-winding to effectively reduce parasitic capacitive coupling

Abstract

Bearing currents are stressing industrial drives which include switching power supplies. Researchers frequently propose new countermeasures. One of the promising approaches is the reduction of parasitic capacitive couplings inside an electrical machine. Slot-opening-embedded electrostatic shields are considered a viable concept. In this work, a way to further increase the effectiveness of the approach is presented. The importance of taking the end windings into account is recalled, and a design of extended slot-opening-embedded electrostatic shields that cover also the winding overhangs is studied. The effect of the suggested extension is examined via modeling electric machines with different power ratings. In addition, the paper closes the knowledge gap of the scaling behavior of the previously introduced capacitive coupling elimination technique, based on the slot-opening-embedded grounded electrode.