Analysis of Direct Torque Control of PMSM with Zero Voltage Vector based Switching Table and implementation in Xilinx System Generator Environment

This paper analyzes the influence of zero voltage vector injection in the implementation Direct Torque Control(DTC) for Permanent Magnet Synchronous Motors(PMSM). The impact on torque ripples and switching frequencies are particularly focused on. This paper speed and torque control of the PMSM based on a 2 Level switching table incorporating the Zero Voltage vectors to decrease torque ripples while maintaining the dynamic response of the system. Taking percentage torque demand as a criterion, the switching states are switched between non zero voltage vector and zero voltage vector switching tables. This enables the system to keep its dynamic behavior all the while decreasing the torque ripples inherent to DTC implementation. The speed control scheme is setup to test the method in variable speed conditions. A Software in Loop (SIL) verification of the proposed method was performed with Xilinx System Generator in MATLAB environment to test the system in fully loaded conditions. The proposed method resulted in a 14 percent reduction in the torque ripples measured while it resulted in a 25 percent reduction in the average switching frequency.