Maximum torque control of an induction machine in the field weakening region

An approach to induction-machine control which ensures maximum torque per ampere over the entire field weakening region is presented. The relation of the output torque capability to the leakage inductance of the machine is examined. By adjusting the base speed for the field weakening operation according to the flux level, the current limit, and the voltage limit, smooth and precise transition into the field weakening operation can be achieved. The proposed scheme is verified through simulation and experiment for a 5 hp laboratory induction motor drive system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>