Direct torque control on a brushless doubly fed reluctance machine

A real time implementation of direct torque control (DTC) (Takahashi, I. and Noguchi, T., 1986), with a position encoder, on a brushless doubly fed reluctance machine (BDFRM) (Liang, F. et al., 1991) is reported. The paper is the extension of papers reported at the same conference in previous years (Yu, J. et al., 37th UPEC, 2002; Yu and Jovanovic, M., 38th UPEC, 2003). Preliminary studies on experimental hardware show consistent results as predicted by computer simulations. The machine offline test is described, as are other hardware devices. The nonlinearity of stator inductance is shown. However, the linear machine model is still a valid approach in that stator inductance varies in a narrow range depending on rotor position. A real time digital controller has been designed based on BDFRM estimation techniques. The results show a promising control potential for BDFRM and will serve as the foundation for further studies, such as sensorless control.