Predictive Direct Torque Control of Switched Reluctance Motor using Torque Difference Technique with Extended Control Set

In this paper, a new predictive direct torque control using torque difference technique (TDT) is proposed for Switched Reluctance Motors (SRMs). Compared with other controllers in the literature, the proposed method can achieve low torque ripple without requiring motor model information such as flux-linkage, inductance, back-electromotive force (back-EMF) or phase resistance. In the proposed method, a torque difference table is designed and updated online by calculating the estimated share of the phase torque. The TDT table is then used for torque prediction and torque error cost function calculation. Moreover, the control voltage set is extended in the design of the TDT table to enable PWM switching. Due to the online update scheme of the TDT table, no parameter tuning is required. Through extensive experimental tests, the proposed TDT controller has been compared with three torque controllers: the conventional direct instantaneous torque controller (DITC) and two different state-of-the-art predictive torque controllers in the literature. Comprehensive evaluations have been performed for wide torque and speed operation and important control metrics are compared. Overall, the proposed TDT can achieve improved torque tracking during steady-state and dynamic-state performance in terms of peak-to-peak and root mean square error of the torque ripple without increasing the computational effort.