Fault-tolerant Speed Synchronous Control of Multi-motor System against Inverter Faults

Considering the servo DC motor subject to possible power inverter or drive faults, a simple fault-tolerant speed synchronous control scheme is proposed for the multi-motor system with ring-coupling structure. By virtue of the advantages of the ring-coupling based synchronization control technique, only the fault detector for testing the faults of each motor subsystem and the fault-tolerant control (FTC) decision logic unit are attached to the multi-motor system in order to modify the reference input of each subsystem. Such strategy does not interfere with the regular system operation and reduces the FTC design complexity. The separation between the tracking controllers design and the synchronization compensators design also reduces the complexity of the control law development, so as to guarantee the expected synchronization precision even in the fault case. Simulations on the speed synchronous control of a triple brushless DC-motor system show the effectiveness of the developed FTC strategy.