Noise Identification And Control Of Electric Powertrain

The direction of national policies,the enhancement of people’s environmental awareness and the commercial value of the future huge market make blade electric vehicles occupy an important position in the automotive market and are considered as the development direction of the future automobile.With the continuous development of electric vehicle technology,the requirements of the NVH performance are getting higher and higher.The replacement of internal combustion engines with electric motors brings a series of new challenges to the NVH of electric vehicle powertrains.Therefore,it is of great significance to study the noise of electric vehicle powertrain.The separation and identification of the Centralized drive-electric powertrain noise is a complex issue.The motor and transmission coupled to each other of the powertrain system,neither traditional nor advanced noise source recognition technology identifies parts with large noise radiation on the machine and can not accurately identify the single noise source,which will certainly affect the result of noise source identification.This article describes the method of noise analysis and analyzes its advantages and disadvantages in the signal recognition process that can accurately identify the noise source,and ensure the follow-up optimization of noise reduction.The paper takes an electric bus as the research object.Firstly,based on the accelerated vehicle test conditions,powertrain of the electric bus and interior noise signals were collected.The noise of the vehicle interior and the noise of vehicle powertrain were analyzed by the method of order spectrum and coherence.The results showed the noise quality of the vehicle at low speed was affected mainly by the meshing gear noise of the transmission,and the noise quality of the vehicle at high speed was affected mainly by the electromagnetic noise of the motor.In order to accurately separate the noise source of the powertrain of the electric bus,the noise signal of the powertrain of the electric bus was collected based on the test conditions of the constant speed bench.And the noise of the powertrain was separated and identified by the noise processing method of EEMD-ICA-CWT.The results showed the shift gear whine noise was taken as the main noise source,while the constant meshed gear whine noise,the stator noise caused by the alveolar harmonics and the electromagnetic noise of the motor controller switching frequency all contribute to this.Finally,to control the noise of the powertrain of the electric bus,the shift gears with more serious noise were optimized.The tooth-shaft dynamics model was established and the gears were optimized based on the orthogonal experiment method.A set of optimal optimization results was used to process the gears.Finally,through experimental verification,it was found that the noise of the powertrain after modification was reduced by about 3dB.