Measures against bearing currents in permanent magnet excited synchronous machines

Abstract:
For variable speed power drive systems, synchronous motors with permanent magnets and inverters are used in industrial applications to obtain power drive systems with high efficiency or high power density. In these drive systems, bearing failures occur due to current flow through the bearings. The current flow in the bearings results from the interaction between the inverter and the synchronous motor. This paper describes measures against bearing currents and their effect on bearing currents.