High-frequency model and simulation for the investigation of bearing current in inverter-driven induction machines

Inverter-generated high-frequency common-mode voltage and resultant common-mode current cause premature motor bearing failure; hence, high-frequency simulations of induction motors exposed to common-mode voltage are presented to gain insights into the motors' common-mode behavior. In addition, electrical discharge machining, one of the mechanisms responsible for bearing degradation, is modeled by combining a voltage-controlled switch with stray motor capacitances. The variation of bearing (shaft) voltage and the magnitude of electrical discharge machining current are shown to be consistent with experimental data reported in literature.