Reconfiguration of tightly-coupled redundant supporting structure in active magnetic bearings under the failures of electromagnetic actuators.

Towards at the active radial magnetic bearing with tightly-coupled redundant supporting structure, we propose a kind of fault-tolerant control strategy to make the remaining structures, under the failures of some electromagnetic actuators, reconfigured by compensating the magnetic flux loss to provide expected supporting force continually. By using FSS (fault status series) to describe the fault status of actuators, an index rule of the current distribution scheme has been designed to resolve different failure conditions of actuators. Fault-tolerant control model has been established to verify the electromagnetic force generation in tightly-coupled redundant supporting structures after failure of actuators. The influence characteristic and mechanism of the bias current coefficient to electromagnetic force generation have been analyzed. The application example shows that fault-tolerant control strategy discussed can restrain the influence of the disturbing force to stabilize the rotor even under the failures of some actuators. In addition, inappropriate selection of the bias current coefficient will be easy to cause electromagnetic force limited by saturation constraint, and unable to provide the desired supporting force, which leads to rotor drop. Improving the real-time performance will effectively reduce the rotor jitter in the reconfiguration of redundant structure discussed. [ABSTRACT FROM AUTHOR]