Minimum-Norm Current Control of Induction Machines

This paper presents a formulation for induction machine minimum-norm current-control. The control strategy developed in this paper minimizes the magnitude of stator current for a desired torque output. Therefore, the optimal operating condition of a machine can be realized by yielding minimum copper losses. The dynamic equations of induction machines in the Clarke transformation are utilized and expanded to deduct a minimum-norm solution for the stator current at a given constant torque. Proposed method's simulation results are presented and compared with the results of a Field-Oriented Control strategy which employs a Sliding-Mode Controller and a Model-Reference Adaptive Observer. The results confirm the capabilities of the proposed method in controlling induction machine's torque and speed accurately at a minimum-norm stator current which leads to lower losses and smaller cable size.