Sensorless fault-tolerant control of multiphase induction machine using virtual winding and adaptive observer

Abstract

Multiphase drive systems have been proposed in high power safety-critical applications because of their excellent fault-tolerant ability. This paper concentrates on speed sensorless fault-tolerant control algorithm of multiphase induction machine. A full-order adaptive observer is adopted to observe the rotor flux and rotor speed, and a virtual winding method is proposed to re-build the symmetrical model when one or several phases are absent in fault mode so that the machine in fault can be dealt as a normally symmetrical machine with some virtual windings. Compared with traditional fault-tolerant control methods, the proposed method can realize precise current control and flux observation under the phase failure condition. Finally, experiments are performed on a five-phase distributed winding induction machine platform. The results demonstrate that the proposed control algorithm can significantly reduce the torque ripple and maintain a relatively stable operation when one phase or two phases are in phase failure condition and without the speed sensor.