Design And Realization Of FFT Spectrum Analyzer Based On LabVIEW And ARM Processor

With the rapid development of power industry,high capacity unit of 600 MW grade and above has become the main unit in power production.As an important part of the unit,auxiliary equipment directly affects the safe and stable operation of the unit,and requires scheduled maintenance and fault diagnosis.Noise and vibration diagnosis techniques are common methods in equipment maintenance and fault diagnosis.Through the spectrum analysis of noise signal and vibration signal,it can judge the running status of equipment and find out its inherent failure.At present,spectrum analysis of the signal is usually realized by the traditional spectrum analyzer,which has high price and bad function scalability and is not easy to deploy in power plants.In view of this,after studying the development of spectrum analyzer,a set of noise and vibration FFT spectrum analyzer based on Lab VIEW and ARM processor is designed and is implemented by combining with virtual instrument technology,embedded technology,and digital signal processing technology in this paper.Firstly,the data acquisition terminal based on ARM processor in this analyzer is carried out,including the design of its software architecture,the selection of sensors,and the hardware design of sampling module,control module and communication module.Secondly,the signal analysis software based on Lab VIEW in this analyzer is described and the design of its software modules is described.In addition,the FFT frequency-domain integral algorithm is used to calculate the vibration velocity in the time-domain analysis module,which eliminates the distortion generated during the acceleration signal integration process and improves the calculation precision and speed.Aiming at the shortcomings of FFT algorithm in spectrum analysis,cepstrum and wavelet transform is introduced in the analysis of noise and vibration signals and have realize sideband detection and mutation detection of the signal.Thirdly,the FFT algorithm has shortcomings of high computational cost and low speed in local spectrum analysis of noise signal and vibration signal,therefore,after studying two kings of ZFFT spectral refinement algorithms,this paper presents an improved ZFFT algorithm based on two-stage filter.By means of multi-level filtering,the improved algorithm can reduce the order of the filter of the ZFFT algorithm under the high refinement ratio,thus improving the performance of the ZFFT algorithm.Experiments show that the improved algorithm is at least 1 times faster than the improved ZFFT algorithm.Finally,the designed spectrum analyzer was built and tested.The results show that the analyzer can realize the accurate acquisition and calculation of the noise signal and vibration signal,which prove the reliability of the analyzer.After applying the analyzer to Huaneng Group Yueyang power plant,the function of frequency-domain analysis and wavelet analysis of the analyzer are verified by the signal collected at the scene,which proves the practicability of the analyzer.