Research On High Temperature Adaptability Of Permanent Magnet Synchronous Motor Control System Based On DSP

Permanent magnet synchronous motor has excellent performance such as high efficiency and easy control.It is widely used in petroleum,automobile and other industries.In petrochemical industry,permanent magnet synchronous motor is mainly used in downhole exploration and acquisition equipment,such as logging while drilling and cutting devices.With the improvement of exploration technology,higher and higher requirements are put forward for the control accuracy of permanent magnet synchronous motor.On the other hand,in the complex working environment such as high temperature in the oil well,the vector drive control system of permanent magnet synchronous motor generally has some problems,such as incomplete decoupling,large amount of calculation and large torque ripple requiring mechanical sensors.To solve this problem,a permanent magnet synchronous motor vector control system based on digital signal processor(DSP)is designed in this paper.The vector control method of positionless permanent magnet synchronous motor with improved proportional resonance(PR)regulator is adopted.Combined with modeling,simulation and experimental test,the accuracy of oil downhole high temperature motor control system is verified,the stability and control accuracy of drive control in high temperature environment are improved.The main contents of this paper are as follows:Firstly,the vector control model is established and verified by simulation.The mathematical simulation model and transformation method of permanent magnet synchronous motor in different coordinate systems are analyzed,and the vector modulation method in space is deeply discussed.Aiming at the problems of large amount of calculation and sensitive to temperature and other parameters of conventional vector control methods,based on the mathematical model and space vector modulation of permanent magnet synchronous motor in different coordinate systems.The control model is established by MATLAB software.Secondly,using the combined control strategy,an improved PR control sensorless current vector control system is established.Aiming at the problems of incomplete decoupling,large amount of calculation and the need to install mechanical sensors in the current widely used control strategy when operating in high temperature environment,by simplifying coordinate transformation,improving operation efficiency,simplifying feedforward compensation phase and cross decoupling term,the influence of motor parameters and temperature fluctuation on control accuracy is reduced;At the same time,the sliding film observer is added to realize the real-time estimation of rotor speed and position,replace the mechanical sensor,simplify the structure,improve the accuracy and reduce the cost.Thirdly,the drive control circuit with TI motion control special digital processing chip(DSP)tms320f28035 as the control core is constructed.By analyzing the failure mechanism of key components in high temperature environment,select appropriate components,optimize the device layout according to the power consumption and sensitivity to the environment,and finally connect with the metal shell through thermal conductive adhesive,so that the heat generated by the components is transferred to the outside,and a reasonable temperature is maintained in the shell.Divide the program,compile the main program,each interrupt service subroutine and configure the driver chip.Finally,build a test platform to verify the control scheme.The speed regulation system is verified in the normal temperature and high temperature environment respectively.The results verify that the permanent magnet synchronous motor drive control system based on the improved PR has good adaptability to the high temperature in the oil well.The system has high working efficiency and can accurately control the torque with low torque ripple.