The generalized theory of indirect vector control for AC machines

The instantaneous torque produced by an AC machine is controllable when vector control is applied. However, the published papers on vector control deal with either induction machines or synchronous machines. A generalized vector-control theory is developed, considering a generalized AC machine as a salient-pole synchronous machine having three kinds of torque, i.e., the field torque, the reluctance torque, and the induction torque. The theory can be extended to the AC machines producing a voluntarily combined torque among the three. The experimental system consisted of applying the generalized vector control theory to a nonsalient-pole synchronous machine with damper winding. It was verified experimentally that the instantaneous torque was controllable, not only in synchronous or induction-machine operation, but also in the transient state between the synchronous-machine operation and induction-machine operation, without any change of the control circuit