Research ArticleIM Direct Torque Control with no flux distortion and no static torque error

- A reduced switching table independent from sector changes is proposed for IM-DTC.
- The proposed control strategy eliminates stator flux distortion.
- The proposed control is compared practically with the classical DTC for a 1.5 kW IM.

The purpose of this paper is to improve DTC control strategy performances. In fact, we propose controlling both stator flux components (real and imaginary) through two hysteresis controllers. Thus, a new switching table which is independent from sector determination, and does not introduce zero voltage vectors is established; with much reduced size when compared to Takahashi's one. The proposed strategy has allowed cutting off with flux and current harmonics related to distortion caused by sector exchanges. Also, we provide theoretical evidence about the existence of static torque error in classical DTC, and propose a simple PI-type controller to cancel it. The proposed strategy is validated by simulation and practically on a DSPace 1104 board, for a 1.5 (kW) induction motor and various torque references.