Direct Torque Control Of Permanent Magnet Synchronous Motor For Vehicles With Constant Switching Frequency

With the improvement of people’s living standards,automobiles have spread to thousands of households.However,due to environmental and energy issues,the development of traditional automobiles has been greatly restricted.Research on new energy automobiles has become the focus of research in various countries.In the research of new energy vehicles,one of the core hardware motors has become a hot spot.In the context of the rapid development of modern control technology,power electronics technology and permanent magnet materials,permanent magnet synchronous motors are widely used in electric vehicles,CNC machine tools and other fields based on their high efficiency,small size,and simple structure.The permanent magnet synchronous motor will be affected by many factors during operation,and its control technology needs to be further improved.Direct torque control technology is widely used due to its low parameter sensitivity,good dynamic control performance,and high robustness.However,it has the problem of unstable switching frequency and needs to be improved and optimized.This article first introduces the structure of permanent magnet synchronous motor and its basic working principle,and then introduces the control methods often used in permanent magnet synchronous motor control in more detail.Based on this,the permanent magnet The idea and realization method of direct torque control of synchronous motor.The structure and control principle of direct torque control are introduced.A more in-depth analysis and research on the stator flux observer.Through the simulation and result analysis of the traditional direct torque control,it is found that the traditional direct torque control has thedefect of unstable switching frequency.In order to obtain better stability for the direct torque control system of permanent magnet synchronous motors,an attempt was made to combine direct torque control with space vector to achieve constant frequency direct torque control.Overcome the shortcomings of traditional direct torque control.Through simulation and result analysis,this method can keep the switching frequency constant and improve the control effect of direct torque control.Then,for the direct torque control system of constant switching frequency,this article introduces the technology of speed sensor,and introduces the method of parameter identification,designs and improves the stator flux observer,and adopts model reference adaptive Speed ? ?identification,realizing direct torque control of sensorless constant frequency.Finally,for the above research methods,at the end of each chapter,the corresponding simulation model is built under the platform of MATLAB/Simlink,permanent magnet synchronous motor direct torque control,constant switching frequency direct torque control and sensorless The simulation model of direct torque control is used to verify the correctness of the control method proposed in this paper.The simulation results show that the method of improving the constant switching frequency of direct torque control proposed in this paper is practical and effective.It can not only fix the inverter The operating frequency of the switching device in the device can also effectively solve the problem of flux linkage and torque ripple caused by the unstable switching frequency of the permanent magnet synchronous motor.The speed sensor-less adaptive method can also effectively measure the speed of the motor,which has strong practicability.