Fault-tolerant AC multidrive system

This paper deals with an original control strategy for AC multidrive systems able to mitigate the effects of failures occurring on one or more drives. A key feature of the proposed technique is that fault tolerance capability is achieved by a suitable reconfiguration of the system in order to allow the healthy drives to provide additional paths for the currents of the faulty drives. Moreover, a modified control algorithm able to enforce the vector control in damaged drives has been implemented, by cooperatively managing some or all the drives of the system. Therefore, differently from previous techniques, the fault tolerance capability is achieved by exploiting the healthy drives, rather than activating back-up inverter legs. As a result, no additional high-frequency switching power devices and related drives circuitries are needed. In the following, two different scenarios will be analyzed, highlighting pros and cons of the proposed approach through simulations and experimental results.