Study Of Vibration Influence Mechanism With Load For Marine Synchronous Generator

The generator is the source of all the power of the ship.As the core component of a ship,when the generator is running and the external force frequency is close to the natural frequency of the generator structure,it will cause resonance.The vibration not only affects the overall structure of the ship,but also cause the internal structure of the generator to be damaged,which and may cause the whole ship to lose power in severe cases.The external force mainly comes from the electromagnetic force.According to the inner magnetic field of the generator,based on the analysis of the influence on the electromagnetic force of by the characters and size of the generator loads,this paper takes the permanent magnet synchronous generator as the research object,and studies the marine generator vibration problem caused by the radial electromagnetic force under different loads.The main contents are as follows:Firstly,The armature reaction characteristics of the generator under pure resistive load and inductive load were analyzed.Based on the basic magnetic potential and permeability of the generator,the magnetic field distribution inside the generator was theoretically calculated by analytical method.According to Maxwell's tensor method,the expression of the radial electromagnetic force in the generator was analyzed,and the relationship between radial electromagnetic force and vibration response of generator was analyzed by Darla Bell principle.According to the characteristics of the armature reaction of the generator in the pure resistive load and inductive load,the variation rule of electromagnetic force in the motor under different loads was analyzed.Secondly,According to the basic size of the generator,ansoft software was used to build the finite element simulation model of generator to change the external circuit to simulate different load changes of the generator.After establishing the model,the magnetic field lines and the magnetic density distribution of the magnetic field in the generator were respectively simulated.The radial electromagnetic force of the generator under different loads was calculated according to the flux density obtained from the simulation.The external load circuit of the generator was changed,and the electromagnetic force in the generator with purely resistive load and inductive load was simulated respectively to verify the correctness of the theoretical analysis.Besides,The experimental platform was set up,and the hardware and software of the experimental platform were designed and the basic functions of the experimental platform wererealized.Combined with the LMS Test.lab vibration test platform,the acceleration of the vibration of the generator foot was used as the vibration response characterization,and the relevant vibration test of the generator was performed on the experimental platform.The generator vibration responses to different rotational speeds at no-load,the response of generators to vibrations with purely resistive loads,and the current and internal power angles of inductive loads were used to test the generator vibration response.Finally,the experimental data are processed,and the experimental results are compared with theoretical simulation.The experimental results verify the reliability of the theoretical analysis.