Vibration Analysis And Reduction Research Of Iron Core Reactor

The problem of vibration and noise of iron core reactors is relatively serious.This vibration and noise problem not only causes noise pollution,but also affects the service life of reactors.Therefore,how to reduce the vibration and noise of reactor has gradually become the focus of domestic and foreign scholars.However,most of the current vibration reduction methods focus on passive vibration reduction,which can not reduce the electromagnetic vibration from the root.To solve this problem,the main work of this paper is as follows:(1)Analysis of the vibration characteristics of the reactor coreThe magnetic-mechanical coupling model of the reactor core was established,and the magnetic field,stress and vibration acceleration of the reactor core under the fundamental wave excitation current were obtained through finite element analysis.The electromagnetic vibration law of the reactor under the fundamental wave was summarized.Then,the vibration characteristics of the reactor was analyzed from the power point of view.According to the relationship between the core vibration acceleration and the peak value of the input power change rate before the magnetic field is unsaturated,it was deduced that the vibration acceleration of the iron core reactor is proportional to the second derivative of the square of the excitation current,which provides a theoretical basis for the subsequent vibration analysis of the reactor.(2)Proposal of an active vibration reduction method based on harmonic injectionAccording to the change of the peak value of the second derivative of current square after superimposing different order harmonics on the fundamental wave,this paper proposed an active method of superimposing the third and fifth order reverse harmonic excitation on the basis of fundamental wave excitation to reduce the vibration acceleration of the reactor core.The optimal mathematical model of reactor injection harmonic excitation based on genetic algorithm was established,and the optimal third and fifth harmonic injection quantity was calculated.Then,the acquisition circuit based on the input power change rate of reactor was built.The curve of power change rate with time before and after harmonic injection was obtained.The average amplitude reduction of power change rate after harmonic injection was calculated.(3)Simulation research on harmonic injection vibration reduction of core reactorIn order to study the vibration characteristics and damping effect of the reactor core before and after harmonic injection more accurately,based on the magnetic mechanical coupling damping model of harmonic injection of the reactor core,the vibration characteristics of the reactor core before and after harmonic injection was analyzed by finite element method.It was concluded that the vibration acceleration amplitude of each point on the core surface of the reactor decreases obviously after harmonic injection without affecting the normal operation of the reactor,which proves the feasibility of the active vibration reduction method based on harmonic injection.(4)Experimental study on the vibration characteristics of a core reactor prototypeThe vibration test platform of the iron core reactor was built to measure the vibration of the reactor before and after harmonic injection under different fundamental current excitation.The comprehensive average damping effect of the reactor after harmonic injection was calculated,which verifies the correctness of the model and the feasibility of the active damping method.This provides a new method for the reactor damping and noise reduction.