Performance analysis of direct torque control of PMSM drive using SVPWM - inverter

Permanent magnet synchronous motors (PMSM) have been universally used as variable speed drives due to its characteristics such as small volume, light weight, high efficiency, small inertia and hence high torque / inertia ratio, maintenance free and ease of control, high steady state torque density create possibility of replacing induction machines with PMSMs in industrial drive applications. PMSM are now widely accepted as high performance drives such as industrial robots and machine tools. A novel direct torque control (DTC) scheme incorporating space vector pulse width modulated (SVPWM) inverter, for speed control of PMSM drive has been presented in this paper, which has advantage of fast dynamic response with low ripples in torque and speed response, elimination of current controllers and least dependency on motor parameters. According to the differences in estimated value of torque and stator flux linkage with actual reference value; the stator voltage vectors are directly selected, in DTC to control the speed of motor. Mathematical model of PMSM and proposed DTC scheme is presented here. A simulation model is developed in MATLAB / SIMULINK to judge the various performance parameters.