Research On Nonlinear Algorithm Of Wide Speed Range Of Permanent Magnet Synchronous Motor Based On Direct Torque Control

Permanent magnet synchronous motor(PMSM) has the advantages of small size, high efficiency and simple structure, so it is widely used in all kinds of high performance drive system. Direct torque control system of permanent magnet synchronous motor which has strong robustness and good dynamic and static performance, has attracted wide attention in the field of power electronics. But because the traditional direct torque control strategy has large flux and torque ripple, so how to improve the direct torque control method become the research focus in recent years. At the same time, because the permanent magnet synchronous motor is a complicated and nonlinear system, so we introduce a nonlinear algorithm, transform the nonlinear system into a linear system, so as to achieve the system decoupling.Firstly, this dissertation reviews the current development of PMSM direct torque control tragedy and nonlinear algorithm, then introduces the mathematical model of the motor, describes how to achieve the traditional direct torque control method of PMSM, and on this basis to establish a direct torque control system model based on SVPWM.Secondly, the related knowledge of feedback linearization theory was introduced, the feedback linearization conditions of direct torque control system was derived, introducing the flux weakening technology, the design of the whole control system was completed. And the simulation model of the system was built in the MATLAB/Simulink simulation software, the system which was designed in this dissertation and the direct torque control system based on SVPWM was compared by simulation, the simulation results verify the feasibility and superiority of the control method proposed in this dissertation.Finally, the hardware in the loop simulation validation has done for the system, then analysis the experiment results. The results show that the system can run stably in the wide range of speed, and has good dynamic and static performance.