Research On MTPA Control System Of Direct Torque Control Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motor is widely used in many motor control systems because of its high efficiency,small size and good speed regulation performance.After vector control was proposed,direct torque control is an effective control method owing to its fast response,no complex coordinate transformation,good robustness and other advantages,it has become a hot research topic in recent years.But torque and flux ripple are usually larger than others in direct torque control systems,this dissertation will focus on the study of this issue.According to the permanent magnet synchronous motor which is a complicated nonlinear system,this dissertation proposes a kind of direct torque control system based on feedback linearization.On this basis,while suppressing torque ripple,the maximum torque current ratio control method is added to realize the decoupling and loss minimization.In this dissertation,the development status and trend of direct torque control of permanent magnet synchronous motor(PMSM)are described.Combining with the mathematical model of permanent magnet synchronous motor,this paper introduces the traditional direct torque control principle,and on the basis of the above,a direct torque control system model based on SVPWM is established and verified by simulation.The control part of SVPWM-DTC system has not been completely decoupled,therefore speed control system with high performance is not gotten and speed is affected by load changes.Through basic theory of feedback linearization,this method can realize decoupling,effectively solve the load effect on the speed and can simplify the design of controller.Simplify the controller design the feedback linearization controller to build the simulation model,and the SVPWM direct torque control system based on the simulation results.For the characteristics of built in permanent magnet synchronous motor with cross axis inductance not equal,the MTPA control link is added to improve the dynamic performance of the system,and the model is built and simulated,the hardware in the loop simulation validation has done for the system.Experiments show that the MTPA control system based on feedback linearization direct torque control keeps the advantages of feedback linearization direct torque control and MTPA control and has good dynamic and static characteristics,low system loss,stable operation.