| The electromechanical coupling dynamic characteristics of Permanent Magnet Synchronous Motorized Spindle(PMSMS)is mainly investigated using finite element method(FEM)and experiment. The thesis mainly considered from three aspects which are calculation of critical speed of the rotor, analysis of magnetic field and torque ripple, and modal analysis of PMSMS.The PMSMS is more and more widely used. Analyzing the dynamic characteristics is very important due to increasing the rotating speed and power constantly. In the course of study of the dynamic characteristics of PMSMS, the critical speeds of the rotor are calculated. Establishing the model of rotor assembly, the mass and rotary inertia of each node are gotten. Using ANSYS to establish the simplified model of rotor assembly, additional gyroscopic effect. The rotor critical speeds are analyzed and calculated. The Camp Bell diagram is obtained. The result shows that the first order critical speed is higher than the rated speed of the motorized spindle. When eccentricity of rotor is existed, the traction force is generated. the traction force is enhanced with increasing of the eccentricity of rotor. Meanwhile, critical speeds is decreased.The magnetic field distribution of the PMSMS is analyzed by the FEM. The torque ripple and the radial electromagnetic force of PMSMS are calculated. Under the condition of the same energy volume of permanent magnet, a kind of novel magnetic pole configuration is designed. The purpose of weakening the vibration and noise of the PMSMS is realized by optimizing shape of permanent magnet poles. The result shows that the rated torque gradually rises, torque ripple firstly decreases, then rises with the permanent magnet middle thickness increasing and the side thickness reducing. There is the minimum of torque ripple. Simultaneously, the fundamental wave amplitude of the radial electromagnetic force gradually increases, the amplitude of the higher harmonic gradually decreases. Therefore, the vibration and noise are effectively reduced.The modal characteristics of PMSMS are investigated by FEM and experimental method. The finite element simulating model is constructed by equivalently simplified each parts. There are two simplified methods about the winding: establishing simplified model of the winding; processing equivalent mass of the winding. The modes of stator with frame and whole spindle assembly units are calculated by using FEM, respectively. The experimental modal analysis of PMSMS is completed by Denmark B&K test system of vibration and acoustics. The accuracy of theoretical modal frequency values is validated. Finally, through optimizing the frame section shape, first to four order natural frequencies are increased. Resonances are avoided. |
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