CN-121977671-A - Multichannel capacitance acquisition system for time-sharing excitation output

CN121977671ACN 121977671 ACN121977671 ACN 121977671ACN-121977671-A

Abstract

The application provides a multichannel capacitor acquisition system with time-sharing excitation output, which belongs to the technical field of airborne controllers and comprises a main processor, a capacitor excitation generation conditioning circuit, a gear matching circuit, a time-sharing excitation output circuit, an excitation signal acquisition circuit, a feedback signal acquisition circuit and an AD acquisition circuit, wherein the main processor is connected with the capacitor excitation generation circuit, the gear matching circuit and the time-sharing excitation output circuit, the time-sharing excitation output circuit is connected with one end of a capacitor to be detected, an excitation signal is transmitted to the input end of the excitation signal acquisition circuit, the other end of the capacitor to be detected is connected with the feedback signal acquisition circuit, the output ends of the excitation signal acquisition circuit and the feedback signal acquisition circuit are connected with the main processor through the AD acquisition circuit, the capacitor excitation generation conditioning circuit generates a sine excitation signal, and the gear matching circuit carries out step excitation according to capacitance values of the capacitor, and the time-sharing excitation output circuit outputs the excitation signal to each acquisition channel capacitor in a time-sharing mode. The application improves the capacitance acquisition efficiency and accuracy and reduces the interference among all channels.

Inventors

YU DONGRAN
LI BINGQIANG
Nie Wanyan

Assignees

苏州长风航空电子有限公司

Dates

Publication Date: 20260505
Application Date: 20251217

Claims (10)

1. The multichannel capacitance acquisition system is characterized by comprising a main processor, a capacitance excitation generation conditioning circuit, a gear matching circuit, a time-sharing excitation output circuit, an excitation signal acquisition circuit, a feedback signal acquisition circuit and an AD acquisition circuit, wherein the output end of the main processor is sequentially connected with the capacitance excitation generation circuit, the gear matching circuit and the time-sharing excitation output circuit, the output end of the time-sharing excitation output circuit is connected with one end of a capacitor to be detected, meanwhile, an excitation signal output by the time-sharing excitation output circuit is transmitted to the input end of the excitation signal acquisition circuit, the other end of the capacitor to be detected is connected with the input end of the feedback signal acquisition circuit, the output end of the excitation signal acquisition circuit and the output end of the feedback signal acquisition circuit are respectively connected with the input end of the main processor through the AD acquisition circuit, the capacitance excitation generation conditioning circuit is used for generating sinusoidal excitation signals and conditioning the sinusoidal alternating current signals, the gear matching circuit is used for performing the time-sharing excitation according to different capacitance values of the capacitor to be detected, the excitation signal acquisition circuit is used for outputting the excitation signals to each capacitor to be detected in a time-sharing mode, the excitation signal acquisition circuit is used for acquiring the excitation signals and converting the excitation signals into direct current signals, and the feedback signals are used for converting the capacitor to be detected into direct current signals.
2. The time-sharing excitation output multichannel capacitance acquisition system according to claim 1, wherein the capacitance excitation generation conditioning circuit comprises a DDS chip and a zeroing circuit which are connected, the DDS chip is connected with the output end of the main processor, and the zeroing circuit is connected with the input end of the gear matching circuit.
3. The multi-channel capacitor acquisition system of claim 2, wherein the zeroing circuit comprises a first operational amplifier, a plurality of resistors and a plurality of capacitors, the inverting input end of the first operational amplifier receives a reference voltage through a third resistor R3 and is connected with the output end through a fifth resistor R5, the non-inverting input end of the first operational amplifier receives an ac excitation signal output by the DDS chip through a fourth resistor R4 and is grounded through a sixth resistor R6, the output end of the first operational amplifier sequentially outputs a sinusoidal ac signal through a first capacitor C1 and a second resistor R2, the output end of the second operational amplifier is grounded through the first resistor R1, and the output end of the second resistor R2 is grounded through the second capacitor C2.
4. The multi-channel capacitor acquisition system with time-sharing excitation output according to claim 3, wherein the gear matching circuit comprises an analog switch, a second operational amplifier and a plurality of resistors, wherein a first end of the analog switch receives a gain resistor selection signal, an output end of the second operational amplifier outputs sinusoidal excitation voltages, the sinusoidal excitation voltages are connected with a second end of the analog switch through parallel four resistors, and are respectively connected with a third end of the analog switch and an inverting input end of the second operational amplifier through a ninth resistor R9, the inverting input end of the second operational amplifier also receives sinusoidal alternating current signals output by a zeroing circuit through an eighth resistor R8, a non-inverting input end of the second operational amplifier is grounded through a tenth resistor R10, one channel of the parallel four resistors is connected with a front end resistor in a gating mode of the analog switch in a proportional amplifying circuit with different proportions, sinusoidal excitation voltages with different amplitudes are output, and the sinusoidal excitation voltages with five gears are output after the parallel connection of the ninth resistor R9 and one channel of the four resistors of the analog switch in a non-gating mode of the analog switch in a switching gear mode.
5. The multi-channel capacitive acquisition system for time-sharing excitation output according to claim 4, wherein the resistance of a first channel of four parallel resistors is set to 24.9kΩ, the resistance of a second channel is set to 14.1kΩ, the resistance of a third channel is set to 8.6kΩ, and the resistance of a fourth channel is set to 7kΩ; When the capacitance to be measured is in the range of 0 pf-114 pf, the first-gear excitation is selected, the analog switch is not gated, the gain resistor is a ninth resistor of 24.9kΩ, and the half peak value of the excitation voltage is 8.77V; when the capacitance to be measured is in the range of 114 pf-225 pf, the analog switch gates the first channel, is connected with a 24.9k omega resistor, and is excited by the second gear, and the half peak value of excitation voltage is 4.44V; When the capacitance to be measured is in the range 225 pf-301 pf, the analog switch gates the second channel, is connected with a 14.1kΩ resistor, and is excited by a third gear, and the half peak value of excitation voltage is 3.33V; when the capacitance to be measured is in the range of 301 pf-424 pf, the analog switch gates the third channel, and is connected with an 8.6k omega resistor, and is excited by a fourth gear, and the half peak value of excitation voltage is 2.36V; when the capacitance to be measured is in the range of 424 pf-600 pf, the analog switch gates the fourth channel, is connected to the 7k omega resistor, and is excited by the fifth gear, and the half peak value of the excitation voltage is 2.03V.
6. The system of claim 1, wherein the time-sharing excitation output circuit comprises a first time-sharing channel selection circuit, a third operational amplifier and a current limiting resistor, the input end of the first time-sharing channel selection circuit is connected with the output end of the gear matching circuit, the non-inverting input end of the third operational amplifier is connected with the output end of the first time-sharing channel selection circuit, the inverting input end of the third operational amplifier is connected with the output end of the third operational amplifier, and the output end of the third operational amplifier is further connected with the capacitor to be tested through the current limiting resistor.
7. The multi-channel capacitor acquisition system with time-sharing excitation output according to claim 1, wherein the feedback signal acquisition circuit comprises a second time-sharing channel selection circuit, a proportional amplifying circuit and a first filtering rectifying circuit which are sequentially connected, wherein the input end of the second time-sharing channel selection circuit is respectively connected with the output end of the time-sharing excitation output circuit and the other end of the capacitor to be detected, the output end of the first filtering rectifying circuit is connected with the AD acquisition circuit, and the feedback signal of the capacitor to be detected of the corresponding channel is input into the proportional amplifying circuit in a time-sharing mode to be proportional amplified, and then the proportional amplified alternating current signal is converted into a direct current signal through the first rectifying and filtering circuit.
8. The system of claim 7, wherein the proportional amplifying circuit comprises a fourth operational amplifier, a standard capacitor Cb and a seventh resistor R7, the standard capacitor Cb and the seventh resistor R7 are connected between an inverting input terminal and an output terminal of the fourth operational amplifier after being parallel, the inverting input terminal of the fourth operational amplifier receives the capacitor feedback signal to be measured, and a non-inverting input terminal of the fourth operational amplifier is grounded.
9. The system according to claim 1, wherein the excitation signal acquisition circuit comprises a third time-sharing channel selection circuit and a second filtering rectification circuit which are connected, an input end of the second time-sharing channel selection circuit is connected with an output end of the time-sharing excitation output circuit, and an output end of the second filtering rectification circuit is connected with the AD acquisition circuit.
10. The multi-channel capacitor acquisition system according to claim 7 or 9, wherein the first filter rectifying circuit or the second filter rectifying circuit comprises a rectifying portion and a filtering portion, the rectifying portion comprises a fifth operational amplifier, a sixth operational amplifier, a plurality of resistors and a plurality of diodes, the non-inverting input end of the fifth operational amplifier is grounded, one end of the inverting input end of the fifth operational amplifier receives a capacitor feedback voltage signal through a thirteenth resistor R13, the other end of the inverting input end of the fifth operational amplifier is connected with one end of a twelfth resistor R12 and the anode of a first diode D1, the output end of the fifth operational amplifier is connected to the inverting input end of the sixth operational amplifier through a second diode D2 and a fourteenth resistor R14, the output end of the fifth operational amplifier is further connected with the cathode of the first diode D1, the other end of the twelfth resistor R12 is connected between the second diode D2 and the fourteenth resistor R14, the inverting input end of the sixth operational amplifier is further connected with one end of an eleventh resistor R11 and one end of a fifteenth resistor R15, and the other end of the inverting input end of the sixth operational amplifier is connected with the thirteenth resistor R13; The filter circuit comprises a seventh operational amplifier, a plurality of resistors and a plurality of capacitors, wherein the positive-phase input end of the seventh operational amplifier is connected with a sixteenth resistor R16 and a seventeenth resistor R17 which are connected in series, the sixteenth resistor R16 and the seventeenth resistor R17 are connected to the negative-phase input end of the seventh operational amplifier through a third capacitor C3, the seventeenth resistor R17 and the positive-phase input end of the seventh operational amplifier are grounded through a fourth capacitor C4, the output end of the seventh operational amplifier is connected with an eighteenth resistor R18, and the other end of the eighteenth resistor R18 is grounded through a fifth capacitor C5.

Description

Multichannel capacitance acquisition system for time-sharing excitation output Technical Field The application relates to the technical field of airborne controllers, in particular to a multichannel capacitance acquisition system for time-sharing excitation output. Background The capacitive sensor measurement technology for aviation fuel is an accurate measurement method based on capacitance change, and is used for monitoring the fuel quantity of an aircraft and ensuring the flight safety and efficiency. The core principle is that fuel oil is used as a dielectric medium, and the fuel oil quantity is determined by detecting the change of the capacitance value. Along with the increasing long voyage of the aircraft, the fuel carrying capacity of the aircraft is greatly increased, the number of fuel tanks is correspondingly increased, the number of fuel measuring capacitance sensors is correspondingly increased, and the corresponding measuring circuit scale and hardware cost are correspondingly increased, so that the fuel measuring capacitance sensor has an important role in measuring the fuel measuring system of the aircraft for the measurement of the fuel capacitance sensors of multiple channels. Disclosure of Invention In view of the above, the embodiment of the application provides a multichannel capacitor acquisition system with time-sharing excitation output, which converts a capacitance signal of a fuel sensor into an electric signal for measurement and aims to solve the technical problem of multichannel measurement. The embodiment of the application provides a multichannel capacitor acquisition system with time-sharing excitation output, which comprises a main processor, a capacitor excitation generation conditioning circuit, a gear matching circuit, a time-sharing excitation output circuit, an excitation signal acquisition circuit, a feedback signal acquisition circuit and an AD acquisition circuit, wherein the output end of the main processor is sequentially connected with the capacitor excitation generation circuit, the gear matching circuit and the time-sharing excitation output circuit, the output end of the time-sharing excitation output circuit is connected with one end of a capacitor to be detected, an excitation signal output by the time-sharing excitation output circuit is transmitted to the input end of the excitation signal acquisition circuit, the other end of the capacitor to be detected is connected with the input end of the feedback signal acquisition circuit, the output end of the excitation signal acquisition circuit and the output end of the feedback signal acquisition circuit are respectively connected with the input end of the main processor through the AD acquisition circuit, the capacitor excitation generation conditioning circuit is used for generating sinusoidal excitation signals and conditioning the sinusoidal alternating signals, the gear matching circuit is used for carrying out the time-sharing excitation according to different capacitance values of the capacitor to be detected, the excitation signal acquisition circuit is used for acquiring the excitation signals to be detected and converting the excitation signals into direct current signals, and the feedback signal acquisition circuit is used for acquiring the excitation signals to be detected into direct current signals, and the feedback signals are used for acquiring the capacitance signals to be detected. According to a specific implementation manner of the embodiment of the application, the capacitance excitation generation conditioning circuit comprises a DDS chip and a zeroing circuit which are connected, wherein the DDS chip is connected with the output end of the main processor, and the zeroing circuit is connected with the input end of the gear matching circuit. According to a specific implementation manner of the embodiment of the application, the zeroing circuit comprises a first operational amplifier, a plurality of resistors and a plurality of capacitors, wherein an inverting input end of the first operational amplifier is respectively connected with an output end through a third resistor R3 and a fifth resistor R5, a non-inverting input end of the first operational amplifier is respectively connected with an alternating current excitation signal output by the DDS chip through a fourth resistor R4 and is grounded through a sixth resistor R6, an output end of the first operational amplifier is sequentially connected with a first capacitor C1 and a second resistor R2 to output a sinusoidal alternating current signal, the first capacitor C1 and the second resistor R2 are grounded through the first resistor R1, and an output end of the second resistor R2 is also grounded through the second capacitor C2. According to a specific implementation mode of the embodiment of the application, the gear matching circuit comprises an analog switch, a second operational amplifier and a plurality of resistors, wherein a first