Improved Torque Control of Permanent Magnet Synchronous Motor Based on Flux Decoupling

Due to its quick response and strong robustness, direct torque control (DTC) system of permanent magnet synchronous motor (PMSM) is widely used in the field of higher response performance. However, the performance of conventional DTC still needs to be explored. Some factors have a great influence on the stability of the system such as: large torque ripple, stator resistance voltage drop, the disadvantage of integral method and nonlinear factors. In order to improve inhere problems above of conventional DTC, this paper uses the mathematical model in dq-frame to observe the flux linkage, and puts forward the definition of "stator flux line". Based on these, an improved torque control algorithm of high-speed motor based on flux decoupling is proposed. The simulation results on a 7.5kW/2400rpm PMSM verified the proposed control scheme has good performance in low speed-region and the algorithm can suppress the torque and flux ripple of the control system to a certain extent.