Research On Key Technologies Of Active Noise Control In Vehicles Based On FPGA

With the increase in economic level and the growth of car ownership,people’s requirements for driving comfort are becoming more and more stringent,the noise level in the car is a key factor affecting the comfort for driving,also one of the main concerns of many automotive manufacturers.Traditional passive noise reduction methods no longer have advantages in low-frequency noise control,Active Noise Control(ANC)has gradually become a research hotspot due to the advantages of small size and low frequency control effect.This paper mainly studies the key technologies in the ANC based on FPGA(Field Programmable Gate Array),and the active noise control in a large area near the headrest of the driver’s seat and co driver’s seat is realized。Firstly,the best ANC control system,adaptive algorithm and identification method is selected based on the research scenario,the effects of filter length and convergence factor on the performance of fixed-point LMS algorithm are analyzed.Secondly,the data interaction scheme between FPGA and related peripherals is designed.The communication between the main chip and related peripherals is realized based on Verilog HDL,and the appropriate electroacoustic equipment to activate the ANC system is selected.Thirdly,based on the perspective of the saving chip resource,the DDS compression algorithm module that generates the feedforward signal is designed,the multi-channel and high-order adaptive algorithm is realized with less resource consumption by proposing the method of multiplexing on-chip RAM and hardware multiplier,and the overall design of ANC system is completed.Finally,the secondary channel identification experiment is carried out and the final order of adaptive filter is selected.Multi channel identification and noise reduction experiments are carried out in the room and in the car respectively.The experimental results verify the effectiveness of ANC system and the target noise is controlled.