Research On Electromagnetic Vibration Of High Speed Solid Rotor Asynchronous Motor With Variable Frequency Power Supply

Three-phase asynchronous motors are widely used in various industrial fields due to their high reliability,low cost,and easy maintenance.Compared with ordinary asynchronous motors,solid rotor asynchronous motors have a rotor that is not laminated but solid.It has the advantages of simple structure,high mechanical strength and strong self-starting ability,so this motor has more important applications in some specific occasions.When a solid rotor asynchronous motor is running,the vibration generated will not only affect the performance of the motor itself,but also affect the service life of the motor equipment.When the variable frequency power supply is used for the solid rotor asynchronous motor,the output contains a lot of harmonics,resulting in a rich electromagnetic force harmonics in the motor,which will increase the vibration of the motor.Therefore,it is necessary to ensure the stability and reliability of the solid rotor asynchronous motor During operation,its vibration must be studied.In this thesis,a solid rotor asynchronous motor is used as the research object to study the electromagnetic vibration.According to the basic parameters of the motor,a finite element model is established.The magnetic flux density of the motor during three-phase sinusoidal power supply operation is analyzed,and the harmonic analysis is performed.According to Maxwell's tensor formula,the radial electromagnetic force density of the motor which changes with space and time during rated operation is calculated.Then,a variable-frequency power supply control circuit for a solid rotor asynchronous motor is established,and a field-circuit coupled time-step finite element model is constructed.The radial electromagnetic force density and frequency spectrum of the motor when the motor is running with variable-frequencypower are analyzed.The natural frequency of the stator core is calculated,and the calculation method of the resonance frequency in the process of variable frequency speed regulation is provided.It provides a theoretical basis for the setting of the variable frequency jump frequency and ensures the stable and reliable operation of the motor.Finally,a three-dimensional finite element model is established on the stator core and the structure of the whole machine,and the modal analysis is carried out to obtain the frequency of the low-order mode shape.The radial electromagnetic force calculated by the three-phase sinusoidal power supply of the motor is added to the stator teeth as the load condition,and the vibration characteristic response analysis is carried out.The statics of the solid rotor are studied,and the influence of speed on the deformation and stress of the solid rotor is analyzed.