Search

CN-122026824-A - Charge amplifier

CN122026824ACN 122026824 ACN122026824 ACN 122026824ACN-122026824-A

Abstract

The invention discloses a charge amplifier, and belongs to the technical field of electronic measurement. The amplifier comprises an input adaptation module, a charge-voltage conversion module, a temperature compensation module, a signal amplification and filtering module, an output driving module and a high-temperature stable power supply module, wherein the input adaptation module is connected with a high-temperature piezoelectric sensor adopting a bismuth layer structure ceramic or lithium niobate ceramic formula, and can stably work in an extremely high-temperature environment at-55 ℃ to 550 ℃. The problems of failure, signal drift and weak anti-interference capability of the existing charge amplifier under a high-temperature environment are solved by adopting a high-temperature resistant material system, adding a temperature compensation module and optimizing shielding and filtering design. The amplifier has high signal conversion precision (nonlinear error is less than or equal to +/-0.5 percent FS), adjustable gain and filtering parameters and excellent protective performance, can be adapted to high-temperature piezoelectric sensors with different specifications, is widely applied to extreme working condition vibration monitoring in the fields of aerospace, energy power, petroleum and natural gas and the like, and provides reliable data support for equipment fault early warning and service life assessment.

Inventors

  • WU HONGWU
  • TAO WEN
  • WANG DONGDONG

Assignees

  • 西安光聚电气有限公司

Dates

Publication Date
20260512
Application Date
20260127

Claims (8)

  1. 1. The charge amplifier is characterized by comprising an input adaptive module (1), a charge-voltage conversion module (2), a temperature compensation module (3), a signal amplification filtering module (4), an output driving module (5) and a high-temperature stable power supply module (6) for supplying power to the modules, which are electrically connected in sequence, wherein the input adaptive module (1) is used for connecting a high-temperature piezoelectric sensor (7) adopting a high-temperature ceramic material formula, the high-temperature ceramic material is bismuth layered structure ceramic or lithium niobate ceramic, and the working temperature range of the high-temperature piezoelectric sensor (7) is-55 ℃ to 550 ℃.
  2. 2. The charge amplifier of claim 1, wherein the input adapter module (1) is a high-temperature coaxial shielded cable interface made of an Inconel nickel-based alloy material, a mica ceramic composite insulating layer and a distributed capacitance compensation circuit are arranged in the high-temperature coaxial shielded cable interface, and the type of the interface is 7/16-27 double-core socket.
  3. 3. The charge amplifier of claim 1, wherein the charge-voltage conversion module (2) comprises a high-temperature optimized JFET field effect transistor, a polyimide film feedback capacitor and a superalloy packaging feedback resistor, wherein the input impedance is more than or equal to 10 12 omega, and the conversion nonlinear error is less than or equal to +/-0.5% FS.
  4. 4. The charge amplifier of claim 1, wherein the temperature compensation module (3) comprises a platinum resistance temperature sensor and a programmable resistance compensation circuit, the temperature measurement range of the platinum resistance temperature sensor is-55 ℃ to 550 ℃, and the compensation circuit counteracts the temperature drift of the piezoelectric coefficient of the high-temperature ceramic material by dynamically adjusting the feedback resistance value of the charge-voltage conversion module (2).
  5. 5. The charge amplifier of claim 1, wherein the signal amplifying and filtering module (4) comprises a programmable gain operational amplifier and a ChebyshevII type active filter, the gain adjustable range is 1-1000 times, and the filtering cut-off frequency adjustable range is 10 Hz-12 kHz.
  6. 6. The charge amplifier of claim 1, wherein the high-temperature stable power supply module (6) has an input voltage of 24V DC and outputs a stable DC voltage of + -15V, a power supply ripple wave of 5mV or less, and a working temperature range of-55 ℃ to 550 ℃.
  7. 7. The charge amplifier of claim 1, wherein the integral housing is of an Inconel nickel-based alloy laser seal welded structure, has a protection rating of IP67, can bear 2000g of mechanical impact, and is internally provided with a heat dissipation channel and a heat insulation layer.
  8. 8. The charge amplifier of any one of claims 1 to 7, wherein the high-temperature piezoelectric sensor (7) with the sensitivity of 5-100 pC/g and the frequency response of 10 Hz-8000 Hz is adapted, the output standardized analog voltage signal range is 0-10V or +/-5V, the output impedance is less than or equal to 50 Ω, and the high-temperature piezoelectric sensor can be directly adapted to the data acquisition system (7).

Description

Charge amplifier Technical Field The invention relates to the technical field of electronic measurement, in particular to a charge amplifier. Background In extreme working condition scenes such as aeroengine turbine blade monitoring, nuclear power station reactor key component vibration detection, underground drilling tool state monitoring and the like, the equipment operation environment temperature is often 530-550 ℃, short-term peak high temperature even occurs under partial working conditions, and meanwhile strong vibration and complex electromagnetic interference are accompanied. In the scene, a core element for vibration monitoring is a piezoelectric sensor, and a sensitive core of the piezoelectric sensor depends on a specific high-temperature ceramic material formula, such as bismuth layered structure piezoelectric ceramic, doped modified lithium niobate ceramic and the like, and the ceramic material can accurately convert vibration acceleration into charge signals only by keeping stable piezoelectric effect at a high temperature of 530-550 ℃. In the prior art, the monitoring scheme aiming at the high-temperature environment has obvious defects that on one hand, a common charge amplifier adopts conventional electronic elements and organic packaging materials, insulation aging, element parameter drift and even circuit short circuit failure easily occur in the high-temperature environment with the temperature above 300 ℃ and cannot adapt to the extreme temperature working condition with the temperature of 530 ℃ to 550 ℃, on the other hand, a charge signal output by a high-temperature piezoelectric sensor has the characteristics of high impedance and weak amplitude, is obviously influenced by thermal noise and electromagnetic interference in the high-temperature environment, has poor signal amplification factor stability and insufficient anti-interference capability, and is difficult to realize accurate conversion from the charge signal to a standardized voltage signal, so that a subsequent data acquisition system cannot acquire reliable vibration data. In addition, the existing charge amplifier and the high-temperature piezoelectric sensor are not good in adaptability, the piezoelectric coefficient of the high-temperature ceramic material can slightly fluctuate along with temperature change, a signal conversion error is increased due to the fact that a common charge amplifier is not provided with a targeted temperature compensation mechanism, meanwhile, a connecting cable between the sensor and the amplifier is prone to being affected by temperature under the high-temperature working condition to generate distributed capacitance change, and the signal distortion problem is further aggravated. These defects severely restrict the accuracy and reliability of vibration monitoring in extremely high temperature environments, and cannot meet the high-precision data requirements of equipment fault early warning, life assessment, research and development optimization in the fields of aerospace, energy power and the like. Disclosure of Invention The invention aims to provide a charge amplifier, which solves the problems of circuit failure, signal drift, weak anti-interference capability, poor suitability and the like in the extremely high temperature environment of 530-550 ℃ in the prior art, realizes the accurate conditioning of a charge signal output by a high-temperature ceramic material piezoelectric sensor, and provides a reliable standardized voltage signal for vibration monitoring under extreme working conditions. The charge amplifier comprises an input adaptation module, a charge-voltage conversion module, a temperature compensation module, a signal amplification and filtering module, an output driving module and a high-temperature stable power supply module for supplying power to the modules, which are electrically connected in sequence, wherein the input adaptation module is connected with the output end of a high-temperature piezoelectric sensor, and the specific structure is as follows: The input adapting module adopts a high-temperature coaxial shielding cable interface, the interface is made of an Inconel nickel-based alloy, a low-loss insulating layer is arranged in the interface and used for connecting the high-temperature piezoelectric sensor and the charge-voltage conversion module, the influence of external electromagnetic interference and temperature on signal transmission is reduced, a distributed capacitance compensation circuit is arranged in the interface, and signal distortion caused by cable distributed capacitance change is counteracted through an adjustable capacitance element. The charge-voltage conversion module is characterized in that a core adopts a high-temperature optimized JFET field effect transistor, a polyimide film capacitor is used as a feedback capacitor, a metal film resistor packaged by high-temperature alloy is selected as a feedback resistor, and the high-efficiency