Optimal flux selection of an induction machine for torque maximization

This paper presents the optimal flux selection of an induction machine for torque maximization over the entire flux weakening region. Based on the bounded constraints on both current and voltage, the optimal flux values which maximize the torque are obtained by solving first-order differential equation of the rotor flux. This leads naturally to three regions of operation in which the induction machine is at either the current constraint, the voltage constraint, or at both simultaneously. The optimal onset of these regions is automatically adjusted to achieve the full utilization of the torque capability. These results provide the significant increase in the available torque compared with any other conventional methods.