Permanent magnet induced electric machine and method for operating such a machine

摘要

If an interturn short-circuit occurs in a stator coil winding of a permanent magnet excited electric machine, a short-circuit current is produced there that results in an electrically induced magnetic alternating flux which corresponds in its value to the permanent magnetic alternating flux flowing through the respective winding and which is opposite in phase. Such a short-circuit current could lead to burn-off of the turn due to its considerable strength and the loss associated therewith. To prevent this, the invention suggests in case of detection of an interturn short-circuit, to entirely short-circuit at least the coil affected by the short-circuit or to apply thereto a corresponding in-phase current and to reduce the excessive short-circuit current in the individual turn or in the individual turn section by way of this overall short-circuit current in the coil. It is thus possible to prevent burn-off of the respective turn part.