Development issues of a Neural observer-based and fault-adaptive sensorless strategy for a multiphase BLDC motor

In this paper there will be presented basically two main subjects: the development procedure of a particular fault-adaptive multiphase sensorless strategy, based on Neural techniques, and the design issues involved by the fault-detection and isolation stages included in the proposed sensorless method. The proposed strategy is particularly suitable to be applied for the implementation of a cheap additional redundancy feature in order to augment the still existing fault-tolerant capabilities of some multiphase drives employed in safety-critical applications. In particular this unusual sensorless strategy is based on a back-EMF observer plus a proper set of coordinate transformations and possesses reconfiguration capabilities with respect to the occurrence of some certain classes of phase faults, gained through the use of a specific fault-adaptation mechanism. At first, the developmental steps of the fault-adaptive strategy will be described in detail after a preliminary motor modeling section, while, in a second step, the design issues linked with the fault-detection and remedial stages will be deeper investigated. Detailed simulation results will be shown at the end to validate the fault-adaptive properties of the proposed multiphase sensorless strategy.