Dynamic Characteristics Analysis And Experimental Research Of IEPE Accelerometer

Piezoelectric accelerometers are widely used in the engineering field,and its output charge signal is weak,due to the influence of material,structure and environment,the dynamic measurement accuracy of acceleration is seriously reduced.IEPE accelerometer is a piezoelectric accelerometer with a built-in signal processing circuit.In this paper,based on the study of the dynamic characteristics of the piezoelectric accelerometer,a low-noise,wide-band IEPE circuit is designed,and the IEPE accelerometer is developed.This accelerometer has broad application prospects in the low-noise,high-precision,wide-band acceleration measurement.Based on the study of the working principle of the IEPE accelerometer,the input and output characteristics of the IEPE interface circuit of the accelerometer are analyzed,and the IEPE circuit with low noise and wide frequency band is designed;the mechanism of the influence of each part of the IEPE accelerometer on the operating frequency of the accelerometer is explored,and deduced the cut-off frequency of the IEPE circuit;on the basis of analyzing the main noise sources and causes of the IEPE accelerometer,a circuit noise model is established,and the analytical expression of the output noise of the IEPE accelerometer is deduced;The signal conditioner with IEPE accelerometer is equipped,and the experiments of amplitude-frequency characteristics and noise characteristics are carried out to verify the correctness of the analysis of the dynamic characteristics of the IEPE accelerometer.The main researching work of this article includes:(1)The amplitude-frequency characteristics of the IEPE accelerometer is studied.According to the mechanical structure of the accelerometer,the parameters of the piezoelectric element and the working principle of the IEPE circuit,the principle of their influence on the amplitude-frequency characteristic is analyzed,the upper and lower cut-off frequencies are deduced and calculated,the main affecting factors of the amplitude-frequency characteristic of the accelerometer are confirmed,provides a theoretical basis of the design of the working frequency band of the piezoelectric accelerometer.(2)The noise characteristics of the IEPE accelerometer is studied.According to the structure and operating principle of the accelerometer,the principle of the noise generated by each component of the accelerometer is analyzed,and the noise model is established to derive the power spectral density of each part of the noise;The paper studies the basic theory of noise,analyzes the correlation of each part of noise and studies the analytical expressions of the total noise of the system,which is used to guide the design of the accelerometer with low noise.(3)IEPE accelerometer signal conditioner is developed.Combined with the IEPE accelerometer amplifier standard,the current excitation and voltage output characteristics of the IEPE accelerometer are studied,and the IEPE accelerometer signal conditioner with constant current source excitation,gain amplification,normalized amplification,high-low pass filtering,and state monitoring indication is designed and developed;the signal conditioner can accurately adjust the constant current excitation,operating frequency band and gain amplification,and indicate the operating state to meet the measurement experiment requirements of the IEPE accelerometer.The amplitude-frequency and noise characteristics of the IEPE accelerometer are studied in this paper,which improve the dynamic characteristics of the accelerometer and provide theoretical guidance for the development of the IEPE accelerometer.