船用高速发电机基波磁场下机座电磁振动

Electromagnetic vibration characteristics of marine high-speed generator frame derived from fundamental magnetic field

以船用高速同步发电机为对象进行电磁振动特性分析。用有限元法计算空载下电机基波气隙磁场引起的径向电磁力波在机座机脚处垂向振动加速度。通过对不同机座安装方式、材料刚度及结构阻尼的振动仿真对比,分析影响振动加速度主因及有限元模型简化处理对计算结果影响。用三维谐波场及瞬态场有限元法计算机脚振动加速度,用电动机运行法测试发电机空载下机座机脚振动加速度。结果表明,仿真与试验结果基本一致,机座及机脚振动受机座安装方式影响较大,定子振幅受材料弹性模量响应较大,在弹性安装/自由状态下机座形变分布主要受结构阻尼影响。该结果可为船用高速电机减振降噪设计、研究提供依据及参考。

With the increase of speed and power-density, the vibration problem of marine high-speed generator has become much more severe. Aiming at this problem, the vertical vibration acceleration at the machine feet of a marine high-speed synchronous generator was studied by finite element method （FEM）, which is derived from the radial electromagnetic force due to the fundamental air-gap magnetic field in no-load condition. The vibration characteristicsis were analysed under different type of frame installations, different material stiffness and different structural damping. The main influential factors were classified clearly by comparative analysis. Moreover, the simplification of finite element model was introduced. The vibration acceleration at the machine feet was calculated by using the three dimensional harmonic field FEM and the transient field FEM respectively. The tested vertical vibration acceleration at machine feet of marine high-speed synchronous generator when running as a no-load motor was presented. The simulation results were compared with the test results, where a substantial agreement was achieved. The results show that frame and feet＇s vibrations are impacted by installations greatly and the material stiffness is the main influential factor of stator＇s vibration amplitude. Moreover, the frame＇s damping has a significant effect on the vibration amplitude distribution under free or flexible installation. The results provide a theoretical reference to the analysis of marine high-speed generator vibration and noise reduction.