Improved Direct Torque Controlled IPM Synchronous Motor using Variable band 12 Sector Control in Two Level Inverter

An improvement over the conventional 6-sector DTC (Direct Torque Control) is seen when the sectors are divided into 12, each being 30 in a 2-level inverter. The 12-sector approach is based on maximum utilization of available vectors as the 6-sector conventional control does not utilize all the vectors available. It is seen that the proposed 12-sector control minimizes the torque ripple in comparison to conventional DTC. IPM motor under DTC is used for analysis due to its rising importance. This paper establishes the 12-sector terminology, the switching table utilized and comparison of conventional 6-sector control to that of proposed 12-sector control. A 5 level torque hysteresis control is introduced to make use of the 12 sectors. The work also shows that having a variable inner hysteresis torque band improves the 12-sector with respect to different operating conditions i.e., speed and torque. The proposed control has been implemented and supported by simulation results.