Direct torque control of PM AC motor with non-sinusoidal flux distribution using state-feedback linearization techniques

In this paper, the authors present a direct torque control scheme for a permanent-magnet (PM) AC motor. For this purpose, state feedback input-output linearization techniques are used with a systematic way of selecting outputs in such a way that not only the torque-voltage (or speed-voltage and position-voltage if necessary) relationship is linearized but a physical criterion is optimized (the minimization of copper losses for example). This strategy can be applied to various types of motors, such as brushless DC motors and PM stepper motors, and can also be seen as method to extend the Park's transformation. Simulations show the high performances of the proposed direct torque control scheme.