Sensorless Synchronous Direct Drive Control Of Three-leaf Roots Vacuum Pump Permanent Magnet Motor

With the continuous development and progress of science and technology,vacuum pumps are the main components of vacuum obtaining equipment,and the demand for vacuum pumps in the field of high-precision industrial manufacturing is increasing.The three-blade Roots vacuum pump is more and more widely used because of its efficient and stable operation.In order to avoid collision,the non-coaxial multi-bladed Roots pump blades need to control the interval angle within 5°,The vacuum pump drive motor cannot be installed with speed and position sensors due to its special structure,and the blade drive motor needs to ensure synchronous and coordinated control.Therefore,this topic studies the sensorless synchronous direct drive control system of the permanent magnet motors of the three-blade Roots vacuum pump.Firstly,a 1.5k W epoxy resin sealed vacuum pump permanent magnet motor is designed for the drive requirements of the vacuum pump blades.The electromagnetic field simulation calculation is carried out with the help of finite element commercial software,so as to obtain the design scheme and specific motor parameters of the permanent magnet motor suitable for the three-blade roots vacuum pump.The mathematical model of the permanent magnet motor of the vacuum pump is established.According to the vector control principle,the permanent magnet motor vector control simulation model is established based on the Matlab/Simulink software to realize the high-precision vector control of the drive motor.Then,on the basis of vector control,the sensorless control model of permanent magnet motor is established based on the principle of model reference adaptation,and the estimation error of the motor speed and rotor position is detected to make it have high reliability and stability.The realization of the system has laid the foundation.Finally,on the basis of the singlemotor sensorless control system,a virtual-motor-based bias-coupled multi-motor synchronous control model is established,and four working conditions are simulated.The four working conditions are:（1）Add 2.5 N×m load to a single motor;（2）Add 3.5N ×m load to a single motor;（3）Add random interference（0-0.2 N ×m）load to two motors at the same time;（4）Adjust the speed of a single motor.For the above working conditions,the speed of the dual motors and the rotor position following are detected.Finally,according to the analysis of the simulation results,the dual-motor control system using the virtual motor-based deviation coupling control idea has a maximum rotor position following error of 2.29° under the four working conditions in this paper,which can ensure that the blade position difference of the Roots pump is within 5°requirements,and have good anti-interference ability.It provides a valuable reference for realizing sensorless synchronous direct drive control of permanent magnet motor for three-blade roots vacuum pump.