Sensorless field-oriented control for six-phase induction machines

In this paper, the classical vector control of six-phase induction machines (SPIM) is analyzed. It is shown that this method is sensitive with respect to the rotor time constant. Then a new vector control law, which minimizes the closed-loop system sensitivity with respect to the motor resistances error, is proposed. It consists in using the back-EMF vector in the control law. The back-EMF vector is estimated by a linear disturbance observer. Then, a reduced-order observer and an adaptive full order observer are applied to sensorless control of SPIM. The simulation results show that the closed-loop system performances are satisfactory using the proposed method.