A Study on Switching Intervals in Classic DTC for Induction Motor

In this paper, a conceptual study on switching intervals in the classic direct torque control (DTC) method and a novel modified method have been proposed. In the switching table of classic DTC, the switching vectors have been changed in sectors with 60 degrees intervals and their boundaries are fixed. In this study, these fixed boundaries and length of switching intervals have been challenged and proved that the performance of the classic DTC can be improved with modified intervals with different lengths and boundaries. The final proposed switching table not also benefits simplicity of implementation as classic DTC switching table, but also it offers better performance especially in the aspect of low torque ripples. The proposed final switching table has been derived by a two-stage optimization process and the results have been proved by simulation results.