Theoretical and experimental analysis of fault-tolerant control strategies for seven-phase induction motor drives

In this paper, a control strategy for seven-phase current-regulated induction motor drives is presented and tested. This strategy allows disturbance-free operations in the case of two stator open-phases, and achieves minimum stator copper losses. The proposed strategy is based on the multiple space vector representation of multi-phase systems. Hence, it is valid in steady-state as well as in transient operating conditions. Three different types of faults are analyzed, depending on the relative position of the magnetic axes of the two faulty phases. Several experimental tests are carried out on a seven-phase asynchronous motor drive prototype, confirming the feasibility of the proposed control strategy.