Phase Current Reconstruction Algorithm for Four-Phase Switched Reluctance Motor under Direct Torque Control Strategy

Existing phase current reconstruction algorithms are developed for switched reluctance motor (SRM) operated under current chopping control (CCC), which generates high torque ripple. Therefore, the direct torque control (DTC) technique is mostly used to control the SRM with minimal torque pulsations. However, the reconstruction of phase currents using the existing one or two sensor methods developed under CCC control will be more difficult to adopt for the DTC scheme due to the simultaneous conduction of all phases. To circumvent this issue, a novel DTC method with reduced sensors is introduced in this paper, which exhibits better performance in comparison to the conventional DTC method. The proposed DTC method avoids the long tail currents thereby limits the conduction of all phases simultaneously. The efficacy of the proposed scheme is validated for four-phase SRM through MATLAB simulations. The results show that the proposed approach helps to operate the drive at the lower torque ripple with reduced cost under various operating conditions in comparison to the conventional DTC.