Behavior of multiphase induction machines with unbalanced stator resistances

Multiphase drives are adopted mainly in high power applications, where the fault detection plays a key role in reducing the maintenance costs and preserving the machine integrity. Fault diagnostics is crucial also for all the applications requiring a high degree of reliability, such as aerospace or marine applications. In this paper the behavior of multiphase induction machines with an odd number of phases is investigated when the stator winding is unbalanced owing to a fault or an incipient damage. A method to detect the stator resistance unbalance, to localize the faulty phase and, at the same time, keep the drive behavior unchanged is proposed. The theoretical analysis and the effectiveness of the control scheme are confirmed by experimental tests.