A loss minimization strategy for PMS motors under direct torque control

The purpose of this paper is to minimize the electrical loss of permanent magnet synchronous motors under a direct torque control (DTC) system. The main idea behind the proposed strategy is to predict a required small change of the stator flux amplitude at each sampling period to reduce the machine electrical loss before the change is applied. Accordingly, at every sampling time, a voltage vector is predicted and applied to the machine to change the flux amplitude in a way that the electrical loss decreases. An extensive set of simulation results show that a significant improvement in the machine efficiency in addition to a very fast and smooth motor response is achieved under the proposed strategy.