Stabilized suspension control strategy at failure of a motor section in a d-q axis current control bearingless motor

This paper presents a stabilized suspension control method when a motor section is unfortunately failed during its operation in the d-q axis current control bearingless motor (d-q BELM). The d-q BELM consists of three sections, in which is divided by every 120° part on its cross section. In each section, the 3-phase winding current is independently controlled by an inverter. Hence, it is possible that the rotor shaft will be supported by the other two sections without mechanical contact even though a section is failed by accidents such as a stator winding short or open, a failure in the inverter. In this paper, a stabilized suspension control strategy at the failure is found and explained in detail. In particular, as the first step, the stabilized control method at no load is focused. The validation of the proposed stabilized control method at the failure is verified by the simulated results using Finite Element (FE) analysis software and the experimental test results using a prototype machine.