Research Of High Speed FFT Pre-scanning System For New Energy Vehicle EMI Test

New energy vehicle attracts people's more and more attention with motor as its power device so that the EMI test becomes very important.Aiming at the lacking of current EMI detection equipment and the improvement of EMI pre-scanning method,“Research and Development of High-speed FFT Pre-scanning System for New Energy Vehicle EMI Test” would be the proper title of this paper doing research on high-speed FFT pre-scanning technology,windowing technology,resolution bandwidth(RBW)adaptive algorithm,system integration and software implementation.This research provided convenient to the new energy vehicle EMI pre-scanning test,and better adapted to the measurement of vehicle conditions with good engineering significance.The research work was supported by the Guangzhou Science and Technology Project(No.201504010037).This paper designs the FFT pre-scanning system architecture,realizes the FFT pre-scanning windowing technology,puts forward the RBW adaptive algorithm,completes the simulation experiment and establishes the new energy vehicle EMI test high-speed FFT pre-scanning system.Finally,through the experiment,this paper verify the system function,adaptive algorithm and rapidity.The main work of the thesis includes:? Analyze system requirements based on the FFT pre-scan function,drum data acquisition function,database management functions,hardware and software compatibility features.Build the new energy vehicle EMI test high-speed FFT pre-scanning system framework based on the business presentation layer,the core business layer,the platform support layer,the basic support layer.Analyze system working mechanism and process to introduce key technology of high precision FFT pre-scanning based on window technology.? The influence of window function,such as rectangular window,Hanning window and Kaiser,and of RBW on the frequency characteristics is studied.Put forward the RBW adaptive algorithm.Verify the feasibility based on the complement mean square error,the signal-to-noise ratio and the peak signal-to-noise ratio obtained by the simulation experiments.? Design and implement of the new energy vehicle EMI test high-speed FFT pre-scanning system.With LabVIEW system modular programming,achieve window processing,data acquisition,parameter settings,adaptive algorithms,data storage and display functions.? Using the vector analyzer,host computer,data acquisition card,industrial computer,antenna,drum system and other devices to build a new energy vehicle EMI test high-speed FFT pre-scanning test platform.Through the design experiment,verify the system function,the adaptive algorithm,the rapidity and analyze the result of the high-speed FFT pre-scanning system.The system validation experiment is carried out to verify that the system can realize the related functions such as frequency amplitude detection,data acquisition,data storage,judgment result,print report and so on.Through the experiment of adaptive algorithm,verify the RBW adaptive algorithm can effectively find the optimal RBW value so that improve FFT pre-scanning accuracy.The system is quick to experiment and verify that the system is significantly reduced in terms of time-consuming compared to the classic sweep mode,with a significant reduction in time-consuming scanning(average time-consuming 0.0253s)than the classic swept pre-scan(average time-consuming 2.1028s),which is more time-saving,efficient and meet the engineering requirements.