Maximum torque control of stator flux-oriented induction machine drive in the field weakening region

In a conventional stator flux-oriented (SFO) induction machine drive system, the field weakening method is to vary the stator flux reference in proportion to the inverse of the rotor speed. This paper investigates that the maximum torque capability cannot be obtained in a conventional SFO system. This paper proposes a new selection method of flux reference to obtain maximum torque capability in the field weakening region by considering voltage, torque, and current limits. The proposed method is verified by simulation and experiment with a 3-hp induction motor drive