Direct torque control of permanent magnet synchronous motor drives with conventional and svm approach

Abstract

The vector control of PMSM allows them to be controlled as the same manner as a separately excited DC motor where the torque is directly proportional to the product of armature current and the excitation flux. Here in the case of PMSM the torque control is achieved by controlling the torque component of current and flux component of current independently. This work presents the basic direct torque control scheme and the DTC with space vector modulation technique (DTC-SVM) to improve the performance of Direct Torque Control of Permanent Magnet Synchronous Motor (PMSM) The mathematical model of PMSM with its working principle is presented. Instead of switching table and hysteresis controller, this technique is based on voltage predictive estimation and space vector pulse width modulation. This control scheme improves the torque and flux response and has a constant switching frequency, which reduces the torque and flux ripples with a fast response. The MATLAB/ Simulink Software is used to simulate the scheme and results shows that this DTC-SVPWM scheme has fast dynamic response and very good performance. The DTC-SVM technique improves the performance of basic DTC performances, which features low torque and flux ripples and eliminates the inverter current harmonics witch constant switching frequency.