NVESTIGATION OF VARIOUS DTC SCHEMES FOR PMSM DRIVE

Abstract

The Permanent magnet synchronous motors (PMSM) drives use direct torque control (DTC). PMSMs are finding several industrial uses due to their excellent power density and efficiency, including hybrid electric vehicles. PMSMs are employed where quick torque response and high performance operation of the machine are required. This study analyses an SVPWM inverter-based direct torque control (DTC) system with PI and SMC for reducing flux and torque ripple in PMSM drives. The analysis demonstrates that the electromagnetic torque increases as the angle between the stator and rotor flux linkages increases. Hence, increasing the stator flux linkage's rotating speed achieves a fast torque response. The DTC method is distinct from approaches that regulate the motor torque and flux values using current controllers in a suitable reference frame. The DTC method does not use any of the present controllers. Based on the difference between the desired and obtained torque and flux values. DTC regulates the voltage source inverter states. One of the six voltage vectors obtained by the inverter (VSI) is chosen to have torque and flux oscillations between the boundaries of two hysteresis bands. This technique uses two- and three-level hysteresis comparators to regulate stator flux and electromagnetic torque. To improve dynamic reaction time and increase robustness during loading and motor parameter variation, an SMC based controller is designed that maintains the increment of motor speed and torque angle. The PMSMs' robustness is increased using the sliding mode controller, which has a solid static and dynamic response, reduces the motor's speed drop, and improves disturbance rejection. The simulation results demonstrated the effectiveness of the SMC-DTC approach. First, a PMSM's properties and operating principles are described. Next, various coordinate systems' mathematical representations of a PMSM are examined. A PMSM is created using MATLAB/Simulink and based on the αβ-reference frame to validate the model. Finally, we compared the results of the two models' simulations to obtain the torque ripple responses for DTC and SMC-DTC.