Research On Power Capacitor Noise Reduction Method Based On Additional Sound Insulation Cavity

With the continuous increase of population and the rapid development of urbanization,DC converter stations are often built near densely populated areas.The level of audible noise generated by the capacitor installations causes serious interference with the normal production and life of the residents around the converter station.The noise generated by a single capacitor can reach 55~65dB.At present,the noise control of a single capacitor is mainly to add a soundproof cavity at the bottom and top positions,and the parameters optimization for the sound insulation cavity is mainly obtained through a large number of experiments,This method is time-consuming and laborious,therefore,the structural parameters of the sound insulation cavity of the capacitor It is of great significance to study the optimization method.The main research content of this article is as follows:1.The simulation method of capacitor vibration and noise control with additional acoustic cavity is studied.Using the LMS Virtual lab,a capacitor vibration and noise simulation model was established.The capacitor was subjected to vibration simulation,and the vibration simulation results were used as boundary conditions for noise simulation to simulate the capacitor noise.Finally,a certain type of capacitor product is taken as an example to verify the application of the simulation model.2.The structural parameters optimization method for the sound insulation cavity at the bottom of the capacitor was studied.The main contribution frequency of noise is determined by the experiment of capacitor vibration and noise test,and a finite element model of the sound insulation cavity is established.Using LMS Virtual Lab,acoustic and vibration coupling calculations were performed on the finite element model of the sound insulation cavity to obtain the characteristic curve between noise frequency and sound insulation of the sound insulation cavity.The DOE technique is used to optimize the structural parameters of the sound insulation chamber.Finally,taking a certain type of capacitor as an example,noise experiments were conducted on acoustic enclosures of different sizes.The experimental results show that the proposed optimization method can effectively improve the design quality and speed of the structural parameters of the sound insulation cavity at the bottom of the capacitor.3.Engineering application verification and effect analysis.First,the formula for calculating the structural loss factor and sound insulation of damping steel plate for capacitor is given.Then,the finite element model of damped steel plate for capacitor and the finite element model of sound insulation cavity were established,and the simulation ofsound insulation was carried out in LMS Virtual lab.Finally,the experimental sample of the soundproof cavity made of the damping steel plate with capacitors is made and the vibration and noise experiments are conducted in the semi-anechoic chamber.The measured data and the simulation data are compared to verify the accuracy of the simulation model and the correctness of the method.