Research On Vibration And Noise Of Reactor Excited By PWM Voltage

Iron core reactor is widely used in power system.It plays a role in limiting short-circuit current,suppressing harmonics and providing reactive power compensation.With the increase of the number and capacity of the reactor,the problem of vibration and noise of iron core reactor becomes more and more obvious.Due to the existence of air gap,iron core reactor has more serious problems of vibration and noise than transformer with the same capacity.Intense vibration will affect the safe operation of equipment and harsh noise will bring noise pollution.Intense vibration will affect the safe operation of equipment,and harsh noise will bring noise pollution,which will affect people’s physical and mental health.Due to the existence of more and more non-linear components in power system,the harmonic content in power system is also increasing.A large number of harmonics will make the reactor’s vibration and noise more obvious.Current researches are mainly focused on the vibration and noise of iron core reactor under the excitation of sinusoidal power supply,but sometimes the iron core reactor works under the non-sinusoidal excitation of PWM excitation.In this paper,the hysteresis loops of silicon steel sheet under sinusoidal and SPWM excitation are tested.The measured magnetization curve is applied to the material parameters of reactor,and the core losses of silicon steel sheet under these two excitations are compared.A two-dimensional simulation model of iron core reactor is established by using COMSOL.The frequency characteristics of Maxwell force,magnetostriction and displacement under sinusoidal excitation and PWM excitation are analyzed.The vibration frequency of reactor under sinusoidal excitation and PWM excitation is deduced mathematically.The deduced results are consistent with the simulation results.The vibration displacements of reactor under sinusoidal excitation and PWM excitation are compared,and the influence of air gap hardness on vibration displacement and natural frequency is analyzed.The vibration accelerations of several iron core reactors under sinusoidal excitation,harmonic excitation and PWM excitation are measured by using vibration and noise testing equipment,vibration and noise analysis software—LMS and acceleration sensor.And the vibration acceleration and frequency at different locations were analyzed.Finally,the noise spectrum of reactor under PWM excitation is tested,and the corresponding relationship between them is found by analyzing the vibration and noise spectrum of reactor under PWM excitation.This paper provides a basis for studying the reliable operation of power system,reducing the system faults caused by abnormal vibration of iron core reactor,reducing the noise of iron core reactor,and optimizing the structural design of iron core reactor.Therefore,this study has a positive significance.