Vibration Analysis And Suppression Of High Torque Direct Drive Rotary Table Drive Motor

With the rapid development of electronic frequency conversion technology, high precision machine tool feed servo system, permanent magnetic material and material processing technology, and in the environment of vigorously promote energy-saving emission reduction in our country, rare earth permanent magnet synchronous motor has been paid more attention in the industry. Permanent magnet synchronous motor has the characteristics of high efficiency, low torque ripple, high torque density and so on. These characteristics make it more and more applied to high precision numerical control machine tools. The vibration level of permanent magnet synchronous motor is an important standard to evaluate the quality and performance of permanent magnet synchronous motor, and it also affects the development of the rotary table drive motor which has been applied to numerical control machine tools. So it is very important to research the electromagnetic vibration of high torque rotary table drive motor. For permanent magnet synchronous motor, the main source of vibration is the electromagnetic force of the air gap magnetic field acting on the stator surface. This project mainly focuses on the following several aspects to analysis:Firstly, the mechanism of electromagnetic force wave of permanent magnet synchronous motor is studied in this project, and the expression of radial air gap magnetic flux density is derived by analytical method. The finite element software is used to analyze the distribution characteristics of the radial air gap magnetic flux density with time and space at no-load and load, and the distribution of the space and time harmonics of air gap magnetic density are obtained. The force wave order, amplitude and frequency of the electromagnetic force are analyzed in the permanent magnet synchronous motor with 10 pole 12 slot unit motor.Secondly, in this thesis, the three-dimensional structure model of permanent magnet synchronous motor with stator structure and rotor structure are established, and their natural frequencies and vibration modes of the system are simulated and calculated by the finite element software. The influence of winding on the natural frequency of stator structure and the influence of the rotary table on the natural frequency of inner and outer rotor structure are analyzed. The first order critical rotation of the rotor structure is calculated, to avoid the resonance due to closing to the frequency and order of electromagnetic force.Lastly, based on the electromagnetic vibration mechanism and the structure parameters of permanent magnet synchronous motor stator, the structure of the stator with unequal teeth tip width, different teeth tip width and the stator with auxiliary slot are analyzed in effects of three schemes on the cogging torque and no-load radial electromagnetic force.