Parametric Research And Optimization Of Stator End Structure Stiffness Based On Large Turbogenerator

Aiming at the vibration problems that occur during the operation of large turbogenerators,the dynamic characteristics of the stator end winding structure and the dynamic response under the action of electromagnetic force are parameterized for stiffness in this thesis.Firstly,An equivalent model fo the single stator end bar is established by Pro/E;Secondly,the overall three-dimensional model of the end winding is established,the modal analysis of the stator end winding is carried out,and the stiffness parameterization study of its dynamic characteristics is carried out;Then,the electromagnetic analysis model of the end is established,the electromagnetic force of the end winding under rated load is calculated,and the stiffness parameterization study of its dynamic response is conducted.Finally,the optimal design of the stator end winding structure is determined.The main work of this thesis includes:1.The structure of the conductor bar is studied,the curve equation of the end of the conductor bar is derived,and the equivalent model of a single conductor bar is established.2.The overall three-dimensional model of the end winding is established,and it is imported into ANSYS Workbench to calculate the modal and natural frequency of the end winding,and the obtained elliptic mode and its corresponding natural frequency are compared with the measured results to verify effectiveness of the model.The stiffness parameterization of the dynamic characteristics of the end winding is further studied to obtain the influence law of different stiffness parameters on the natural frequency of the elliptical mode.The results show that by reducing the Young's modulus of the radial braces,the natural frequency of the elliptical mode of the stator end winding is significantly reduced.3.A three-dimensional electromagnetic field analysis model of the generator end area is established by Maxwell,and the time and space changes of the electromagnetic force density on the end winding under the rated load are calculated.Based on the numerical simulation results of electromagnetic force,the calculated electromagnetic force is imported into the structural analysis finite element model,and the maximum amplitude value of the end winding under the rated load electromagnetic force is simulated by ANSYS Workbench to further affect the end winding under the rated load electromagnetic force.The stiffness parameterization study of the dynamic response under the paper is conducted to obtain the influence law of different stiffness parameters on dynamic response.The results show that by increasing the Young's modulus of the pad,the maximum displacement of the stator end windings is significantly reduced.4.The single factor sensitivity analysis of dynamic characteristics and dynamic response is carried out.The influence law of dynamic characteristics and dynamic response is studied when single stiffness factor and multiple stiffness factor change.Finally,an optimized design scheme for the stator end winding structure is obtained.