Research On Speed Sensorless Direct Torque Control Strategy Of Permanent Magnet Synchronous Motor

The design of the permanent magnet synchronous motor is different from that of the general motor.Its structure is simple and efficient,which has attracted great attention.If the control system of the permanent magnet synchronous motor can be optimized,the advantages of the permanent magnet synchronous motor can be greatly improved.Although it is efficient,it cannot cover up the deficiencies of the control method.The emergence of position sensorless plays an important role in the control of the motor,but it also brings some drawbacks,that is,it increases the cost of the motor and the cost of maintenance.The speed sensorless control strategy of permanent magnet synchronous motor can reduce the volume of the motor,reduce the maintenance cost,and most importantly,it can make the control accuracy of the motor higher.This article first establishes a complete mathematical model of the permanent magnet synchronous motor,and introduces the direct torque control,which has a simpler control principle.For the traditional direct torque control,although it can meet the general control method,it has some deficiencies in the precision control.The torque ripple will inevitably affect the control accuracy.To solve this problem,direct torque control based on SVPWM is introduced.Secondly,the introduced SVPWM technology requires rotation coordinate transformation,so its position information plays a vital role in the speed regulation performance of PMSM.MRAS\ uses the expression without state variables as the reference model,and the expression with the state variables to be estimated as the adjustable model,and selects the appropriate adaptive rate according to the motor type and motor parameters to realize the online estimation of the motor state.However,there will be a detection dead zone when the motor is low speed,and it is difficult to accurately detect the motor rotor.In order to overcome the problem of accurate estimation of the motor speed at zero speed and low speed,the method of injecting high-frequency voltage is adopted.Using MATLAB for simulation verification can solve the defect of insufficient identification of motor rotor information under low-speed conditions.Finally,use TI’s TMS320F28335DSP chip as the core component of the motor control,through the construction of the experimental platform,it is proved that in actual situations,the control method used in this article can meet the basic control requirements.