Integrated tester for low-temperature liquid rocket engine

Abstract

The invention discloses an integrated tester for a low-temperature liquid rocket engine. The integrated tester comprises an AC / DC power supply module, an electromagnetic valve current acquisition board, a sensor voltage acquisition board and an upper computer, wherein the electromagnetic valve current acquisition board is used for generating an MCU control signal and controlling the on-off of power supply of an electromagnetic valve according to the MCU control signal; electromagnetic valve action current signals are converted into digital signals; setting a bias voltage, and self-checking whether the channel function is normal or not by comparing the difference between the bias voltage and the recovery voltage; the sensor voltage acquisition board is used for analyzing the control instruction; acquiring a voltage value according to the second MCU control signal, processing the voltage value to obtain a second digital signal, and transmitting the second digital signal to the upper computer; setting a second bias voltage, and automatically checking whether the channel function is normal or not by comparing the difference between the second bias voltage and the second recovery voltage; and the upper computer is used for sending the control instruction to the sensor voltage acquisition board. The invention has the advantages of high integration, miniaturization and light weight.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic liquid rocket engine technology, and particularly relates to an integrated test instrument for cryogenic liquid rocket engines. Background Technology

[0002] Existing rocket engine testing equipment is bulky, difficult to transport, and has low integration. The testing process is complex, requiring simultaneous connection of multiple testing devices and a host computer, which can easily lead to incorrect device connection polarity. The human-machine interface is unclear, making it prone to misoperation. Furthermore, the testing accuracy is low, the sampling speed is slow, and it is impossible to collect complete test process data. With the development of next-generation liquid hydrogen-liquid oxygen rocket engine technology, the characteristics of engine testing parameters are becoming more numerous and wide-ranging, requiring higher measurement accuracy, higher sampling rates, and wider bandwidths. The demands for integration and miniaturization of ground testing equipment are also gradually increasing. Existing equipment is insufficient to meet the high-density launch testing missions and engine testing requirements of new engines; therefore, it is necessary to design a ground testing device with high integration, miniaturization, high measurement accuracy, and ease of operation. Summary of the Invention

[0003] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide an integrated test instrument for cryogenic liquid rocket engines, which has the advantages of high integration, miniaturization and lightweight.

[0004] The objective of this invention is achieved through the following technical solution: an integrated test instrument for cryogenic liquid rocket engines, comprising: an AC / DC power module, a solenoid valve current acquisition board, a sensor voltage acquisition board, and a host computer; wherein, the AC / DC power module: receives 220V AC voltage, converts the 220V AC voltage into +15V DC voltage and +27V DC voltage, provides the +27V DC voltage to the solenoid valve current acquisition board and the sensor voltage acquisition board respectively, and provides the +15V DC voltage to the sensor voltage acquisition board; the solenoid valve current acquisition board: receives the +27V DC voltage, converts the +27V DC voltage into a preset DC voltage; receives the solenoid valve acquisition command sent by the network port of the sensor voltage acquisition board, generates an MCU control signal, controls the power supply on / off of the solenoid valve according to the MCU control signal; acquires the solenoid valve action current signal, converts the solenoid valve action current signal into a voltage signal, and converts the voltage signal... The signal is converted into a digital signal by an ADC and transmitted to the sensor voltage acquisition board. A bias voltage is set, and the self-test channel function is checked by comparing the difference between the bias voltage and the sampled voltage. The sensor voltage acquisition board receives +15V DC and +27V DC voltages, converting the +27V DC voltage to a preset DC voltage. It receives control commands from the host computer, parses the commands, and if the command is a solenoid valve acquisition command, transmits it to the solenoid valve current acquisition board; if the command is a sensor acquisition command, it generates a second MCU control signal. The voltage value is acquired based on the second MCU control signal, processed to obtain a second digital signal, and transmitted to the host computer. A second bias voltage is set, and the self-test channel function is checked by comparing the difference between the second bias voltage and the second sampled voltage. The host computer sends control commands to the sensor voltage acquisition board.

[0005] In the aforementioned integrated test instrument for cryogenic liquid rocket engines, the solenoid valve current acquisition board includes a first DC / DC power supply module, a solenoid valve power supply control circuit, a solenoid valve current acquisition circuit, and a first MCU. The first DC / DC power supply module receives a +27V DC voltage, converts it to +5V and +3.3V DC voltages, provides the +5V DC voltage to the solenoid valve current acquisition circuit, and provides the +3.3V DC voltage to the first MCU. The solenoid valve power supply control circuit receives a +27V DC voltage and receives MCU control signals, controlling the on / off state of the solenoid valve power supply according to the MCU control signals. The solenoid valve current acquisition circuit acquires the solenoid valve operating current signal, converts the solenoid valve operating current signal into a voltage signal, and... The voltage signal is converted into a digital signal by an ADC and transmitted to the first MCU. When there is no external input, a bias voltage is received, processed to obtain a sampled voltage, and transmitted to the first MCU. The first MCU: receives the solenoid valve acquisition command, generates an MCU control signal, and transmits the MCU control signal to the solenoid valve power supply control circuit; generates a bias voltage and transmits the bias voltage to the solenoid valve power supply control circuit; acquires the sampled voltage and compares the difference between the bias voltage and the sampled voltage to see if it is within a preset error range. If it is within the preset error range, the solenoid valve current acquisition circuit is normal; if it is not within the preset error range, the solenoid valve current acquisition circuit is abnormal; receives the digital signal and transmits the digital signal to the sensor voltage acquisition board.

[0006] In the aforementioned integrated cryogenic liquid rocket engine tester, the sensor voltage acquisition board includes a second DC / DC power supply module, a sensor power supply and voltage acquisition circuit, a second MCU, and a network port. The second DC / DC power supply module receives +27V DC voltage, converts it to +5V DC voltage and +3.3V DC voltage, provides the +5V DC voltage to the network port, and provides the +3.3V DC voltage to the second MCU. The sensor power supply and voltage acquisition circuit receives +27V DC voltage; receives control signals from the second MCU, acquires voltage values ​​based on these signals, processes the voltage values ​​to obtain a second digital signal, and transmits the second digital signal to the second MCU; when there is no external input, it receives a second bias voltage, processes it to obtain a second sampling voltage, and transmits the second sampling voltage to the second MCU. The second MCU receives sensor acquisition commands, generates a second MCU control signal, and... The second MCU control signal is transmitted to the sensor power supply and voltage acquisition circuit; a second bias voltage is generated and transmitted to the sensor power supply and voltage acquisition circuit; a second sampling voltage is acquired, and the difference between the second bias voltage and the second sampling voltage is compared to see if it is within a preset second error range. If it is within the preset second error range, the sensor power supply and voltage acquisition circuit is normal; if it is not within the preset second error range, the sensor power supply and voltage acquisition circuit is abnormal; digital signals and second digital signals are received and transmitted to the network port; the network port receives digital signals and second digital signals and transmits the received digital signals and second digital signals to the host computer; it receives control commands sent by the host computer, parses the control commands, and if the control command is a solenoid valve acquisition command, it transmits the solenoid valve acquisition command to the solenoid valve current acquisition board; if the control command is a sensor acquisition command, it transmits the sensor acquisition command to the second MCU.

[0007] In the aforementioned integrated cryogenic liquid rocket engine test instrument, the solenoid valve power supply control circuit includes resistors R1 and R2, optocoupler B1, R3, R4, diode V1, PNP transistor V2, diode V3, N-MOSFET V4, and resistor R5. The positive terminal of resistor R1 is connected to the digital voltage VCC1, and the negative terminal of resistor R1 is connected to the MCU control I / O port DZ and the negative terminal of the light-emitting side of optocoupler B1. The negative terminal of resistor R2 is connected to the positive terminal of the light-emitting side of optocoupler B1. The positive terminal of the photosensitive side of optocoupler B1 is connected to the positive terminal of resistor R3, the positive terminal of diode V1, and the base of PNP transistor V2. The negative terminal of the photosensitive side of optocoupler B1 is connected to the negative terminal of resistor R3, the positive terminal of resistor R4, the negative terminal of diode V3, and the source of N-MOSFET V4. The negative terminal of diode V1 is connected to the emitter of transistor V2 and the N-MOSFET. The gate of V4; the collector of transistor V2 is connected to the negative terminal of resistor R4; the supply voltage DCY_P is connected to the drain of N-MOSFET V4; the positive terminal of diode V3 is connected to the positive terminal of resistor R5, and the negative terminal of resistor R5 is connected to ground B- of the current sampling circuit of the current measuring valve.

[0008] In the aforementioned integrated test instrument for cryogenic liquid rocket engines, the solenoid valve current acquisition circuit includes a first voltage divider resistor R6, a first differential resistor R7, a second differential resistor R8, a third differential resistor R9, a fourth differential resistor R10, a fifth differential resistor R11, a sixth differential resistor R12, a first isolation operational amplifier N1, a second operational amplifier N2, capacitors C1, C2, C3, and C4; wherein, the positive terminal of the first voltage divider resistor R6 is connected to the negative terminal DCF_-B of the solenoid valve and the positive terminal of the first differential resistor R7 respectively; the negative terminal of the first voltage divider resistor R6 is connected to the power supply ground -B of the solenoid valve respectively. The positive terminal of the second differential resistor R8 is connected to the positive input terminal of the first differential resistor R7, and the negative terminal of the second differential resistor R8 is connected to the negative input terminal of the first isolation operational amplifier N1; one end of the capacitor C1 is connected to the positive input terminal of the first isolation operational amplifier N1, and the other end of the capacitor C1 is connected to the negative input terminal of the first isolation operational amplifier N1; the power supply terminal of the input side of the first isolation operational amplifier N1 is connected to the analog voltage VCC2, and the ground terminal of the input side of the first isolation operational amplifier N1 is connected to the power supply ground -B of the solenoid valve; the power supply terminal of the isolated output side of the first isolation operational amplifier N1 is connected to the analog voltage VCC2. The first isolation operational amplifier N1 is connected to analog voltage VCC3 and one end of capacitor C3, respectively. The other end of capacitor C3 is connected to analog ground AGND. The ground terminal of the output side of the first isolation operational amplifier N1 is connected to analog ground AGND. The positive terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the third differential resistor R9, and the negative terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the fourth differential resistor R10. The negative terminal of the third differential resistor R9 is connected to the non-inverting input of the second operational amplifier N2, and the negative terminal of the fourth differential resistor R10 is connected to the inverting input of the second operational amplifier N2. The positive terminal of the fifth differential resistor R11 is connected to the second... The positive gain terminal of operational amplifier N2 is connected to the negative gain terminal of the fifth differential resistor R11. The positive terminal of the sixth differential resistor R12 is connected to the output terminal of the second operational amplifier N2. The negative terminal of the sixth differential resistor R12 is connected to the ADC voltage acquisition terminal DCFAI and one end of capacitor C3. The other end of capacitor C3 is connected to analog ground AGND. The bias terminal of the second operational amplifier N2 is connected to the MCU built-in DAC interface VREF_DCF. One end of capacitor C2 is connected to the non-inverting terminal of the second operational amplifier N2, and the other end of capacitor C2 is connected to the inverting terminal of the second operational amplifier N2.

[0009] In the aforementioned integrated cryogenic liquid rocket engine test instrument, the sensor power supply and voltage acquisition circuit includes diode V5, resistors R13, R14, R15, R16, R17, and R18, isolation operational amplifier N3, operational amplifier N4, capacitors C5, C6, C7, C8, C9, C10, C11, C12, and C13; wherein, the positive terminal of diode V5 is connected to the pressure sensor output voltage YLZ and the positive terminal of resistor R13 respectively; the negative terminal of diode V5 is connected to YLGND; the negative terminal of resistor R13 is connected to... Connect the positive terminal of resistor R14, one end of capacitor C5, and the non-inverting input of isolation operational amplifier N3. Connect the negative terminal of resistor R14, the other end of capacitor C5, the other end of capacitor C6, the other end of capacitor C7, the other end of capacitor C8, and the input ground of isolation operational amplifier N3 to the pressure sensor ground YLGND. Connect the positive terminal of the differential output of isolation operational amplifier N3 to the positive terminal of resistor R15, and connect the negative terminal of resistor R15 and one end of capacitor C11 to the non-inverting input of operational amplifier N4. Connect the negative terminal of the differential output of isolation amplifier N3 to the positive terminal of resistor R16, and connect the negative terminal of resistor R16 and the other end of capacitor C11 to the non-inverting input of operational amplifier N4. One end of each resistor is connected to the inverting input of operational amplifier N4; the positive end of resistor R17 is connected to the positive gain input of operational amplifier N4, and the negative end of resistor R17 is connected to the negative gain input of operational amplifier N4; the output of operational amplifier N4 is connected to the positive end of resistor R18, the negative end of resistor R18 and one end of capacitor C13 are both connected to the ADC voltage acquisition interface ADC_YL, and the other end of capacitor C13 is connected to analog ground AGND1; the bias terminal of operational amplifier N4 is connected to the built-in DAC interface VREF_YL of the MCU; the isolated output power supply of operational amplifier N4 is connected to analog voltage VCC5. One end of capacitor C12 is connected to analog ground AGND1, and the other end of capacitor C12 is connected to analog ground AGND1. One end of capacitor C6, one end of capacitor C7, and the VDD1 terminal of isolation operational amplifier N3 are all connected to analog voltage VCC4. One end of capacitor C8 is connected to the VCAP terminal of isolation operational amplifier N3. The VDD2 terminal of isolation operational amplifier N3, one end of capacitor C9, and one end of capacitor C10 are all connected to analog voltage VCC5. The GND2 terminal of isolation operational amplifier N3, the other end of capacitor C9, and the other end of capacitor C10 are all connected to analog ground AGND1.

[0010] In the aforementioned cryogenic liquid rocket engine integrated tester, when the MCU control IO port DZ is low, the light-emitting side of the optocoupler B1 is turned on, the N-MOSFET V4 is turned on, and the power supply voltage DCY_P is connected to the power supply output DCF of the solenoid valve.

[0011] In the aforementioned cryogenic liquid rocket engine integrated tester, when the MCU control IO port DZ is high, the light-emitting side of the optocoupler B1 is cut off, the N-MOSFET V4 is cut off, and the power supply voltage DCY_P is disconnected from the solenoid valve power supply output DCF.

[0012] In the aforementioned cryogenic liquid rocket engine integrated tester, due to the parasitic capacitance of N-MOSFET V4, when switching from conduction to turn-off, the output of optocoupler B1 becomes low, while the voltage of the gate and source of N-MOSFET V4 does not change immediately, but decreases slowly.

[0013] In the aforementioned cryogenic liquid rocket engine integrated tester, when the output terminal of the photosensitive side of the optocoupler B1 goes low, there is a voltage difference between the emitter and base of the transistor V2 and between the emitter and collector. The transistor V2 operates, providing a fast discharge channel for the gate and source of the N-MOSFET V4, thus accelerating the turn-off of the N-MOSFET V4.

[0014] Compared with the prior art, the present invention has the following advantages: (1) The present invention solves the problems of large size, poor integration and difficult operation of existing testing equipment. The test instrument is miniaturized while meeting the testing requirements and accuracy of cryogenic liquid rocket engines, integrates multiple testing functions into one, and can adapt to the humid salt spray environment of Hainan. (2) The tester of the present invention can independently test the circuit, which reduces the tester's self-test work and improves efficiency; the host computer adds automatic interpretation and linkage test functions, which greatly optimizes the engine test process. Attached Figure Description

[0015] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a structural block diagram of the integrated cryogenic liquid rocket engine tester provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the solenoid valve power supply control circuit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the solenoid valve current acquisition circuit provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the sensor power supply and voltage acquisition circuit provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of engine testing connection provided in an embodiment of the present invention. Detailed Implementation

[0016] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0017] Figure 1 This is a structural block diagram of the integrated test instrument for cryogenic liquid rocket engines provided in an embodiment of the present invention. Figure 1 As shown, the integrated test instrument for cryogenic liquid rocket engines includes: an AC / DC power module, a solenoid valve current acquisition board, a sensor voltage acquisition board, and a host computer; among which, AC / DC power module: Receives 220V AC voltage, converts 220V AC voltage into +15V DC voltage and +27V DC voltage, supplies +27V DC voltage to the solenoid valve current acquisition board and sensor voltage acquisition board respectively, and supplies +15V DC voltage to the sensor voltage acquisition board. Solenoid valve current acquisition board: Receives +27V DC voltage and converts it to a preset DC voltage; receives solenoid valve acquisition commands sent from the sensor voltage acquisition board's network port, generates MCU control signals, and controls the solenoid valve's power supply on / off according to the MCU control signals; acquires the solenoid valve's operating current signal, converts it into a voltage signal, converts the voltage signal into a digital signal via an ADC, transmits the digital signal to the sensor voltage acquisition board's serial port, and then transmits it to the host computer through the sensor voltage acquisition board's network port; sets the bias voltage and checks the self-test channel function by comparing the difference between the bias voltage and the sampled voltage. Sensor voltage acquisition board: Receives +15V DC voltage and +27V DC voltage, converts +27V DC voltage to a preset DC voltage; receives control commands sent from the host computer, parses the control commands; if the control command is a solenoid valve acquisition command, it transmits the solenoid valve acquisition command to the solenoid valve current acquisition board; if the control command is a sensor acquisition command, it generates a second MCU control signal; acquires voltage values ​​according to the second MCU control signal, processes the voltage values ​​to obtain a second digital signal, and transmits the second digital signal to the host computer; sets a second bias voltage, and checks whether the self-test channel function is normal by comparing the difference between the second bias voltage and the second sampled voltage; Host computer: Sends control commands to the sensor voltage acquisition board.

[0018] The instrument consists of two solenoid valve current acquisition boards and one sensor voltage acquisition board. To minimize the size of the instrument, three printed circuit boards are stacked vertically. Thermally conductive silicone is added to the printed circuit boards for heat dissipation. Considering the humid and salty environment of Hainan, the outer surface of the printed circuit boards is coated with polyurethane varnish. The outer casing uses an aluminum alloy chassis structure, which improves the strength of the equipment while meeting the requirements of lightweight and miniaturization, making the product easy to disassemble and maintain. A fully sealed structure is adopted to suppress the influence of static electricity on the equipment, and a floating ground design is used to improve the electromagnetic interference resistance of the testing equipment.

[0019] The tester can be functionally divided into an AC / DC power supply module, a solenoid valve current acquisition board, a sensor voltage acquisition board, and a host computer. The AC / DC power supply module converts 220V AC signals to +15V and +27V DC voltages. The solenoid valve current acquisition function is implemented through two identical solenoid valve current acquisition boards, #1 and #2, each acquiring 14 solenoid valve current signals, for a total of 28 channels. The sensor voltage acquisition board acquires 12 channels of remote pressure sensor signals. The host computer provides human-machine interaction functions, including issuing commands, parsing data, storing data, and retrieving configuration information.

[0020] The solenoid valve current acquisition board includes a first DC / DC power supply module, a solenoid valve power supply control circuit, a solenoid valve current acquisition circuit, and a first MCU.

[0021] The first DC / DC power supply module receives +27V DC voltage, converts it into +5V DC voltage and +3.3V DC voltage, supplies the +5V DC voltage to the solenoid valve current acquisition circuit, and supplies the +3.3V DC voltage to the first MCU; the solenoid valve power supply control circuit receives +27V DC voltage and receives MCU control signals, and controls the solenoid valve power supply on and off according to the MCU control signals.

[0022] Solenoid valve current acquisition circuit: Acquires the solenoid valve operating current signal, converts the solenoid valve operating current signal into a voltage signal, converts the voltage signal into a digital signal via an ADC, and transmits the digital signal to the first MCU; when there is no external input, it receives the bias voltage, processes the bias voltage to obtain the sampling voltage, and transmits the sampling voltage to the first MCU.

[0023] The first MCU: receives and acquires commands from the solenoid valve, generates MCU control signals, and transmits the MCU control signals to the solenoid valve power supply control circuit; generates a bias voltage and transmits the bias voltage to the solenoid valve power supply control circuit; acquires the feedback voltage and compares the difference between the bias voltage and the feedback voltage to see if it is within the preset error range. If it is within the preset error range, the solenoid valve current acquisition circuit is normal; if it is not within the preset error range, the solenoid valve current acquisition circuit is abnormal; receives digital signals and transmits the digital signals to the sensor voltage acquisition board.

[0024] The solenoid valve current acquisition board (including #1 and #2) can be functionally divided into a DC-DC power supply module, a solenoid valve power supply control circuit, a solenoid valve current acquisition circuit, an MCU, and peripheral circuits. The DC-DC power supply circuit converts the 27V DC voltage to the +5V, +3.3V, etc., DC voltages required by the solenoid valve current acquisition board. The solenoid valve power supply control circuit receives control signals from the MCU to control the power supply to the corresponding solenoid valve. The solenoid valve current acquisition circuit acquires the solenoid valve's operating current signal, converts the current signal into a voltage signal, and then converts it into a digital signal via an ADC before sending it to the MCU. The MCU sets the bias voltage through its internal DAC. When there is no external input, it can self-test whether the channel function is normal by comparing the difference between the bias voltage and the sampled voltage. The MCU and peripheral circuits ensure normal MCU operation. The MCU receives commands from the sensor voltage acquisition board via a serial port and sends the corresponding solenoid valve voltage data to the sensor voltage acquisition board.

[0025] The sensor voltage acquisition board includes a second DC / DC power supply module, a sensor power supply and voltage acquisition circuit, a second MCU, and a network port. The second DC / DC power module receives a +27V DC voltage, converts the +27V DC voltage into a +5V DC voltage and a +3.3V DC voltage, supplies the +5V DC voltage to the network port, and supplies the +3.3V DC voltage to the second MCU.

[0026] Sensor power supply and voltage acquisition circuit: Receives +27V DC voltage; receives control signals from the second MCU, acquires voltage values ​​according to the control signals from the second MCU, processes the voltage values ​​to obtain a second digital signal, and transmits the second digital signal to the second MCU; when there is no external input, receives a second bias voltage, processes the second bias voltage to obtain a second sampling voltage, and transmits the second sampling voltage to the second MCU.

[0027] The second MCU: receives the sensor acquisition command, generates a second MCU control signal, and transmits the second MCU control signal to the sensor power supply and voltage acquisition circuit; generates a second bias voltage and transmits the second bias voltage to the sensor power supply and voltage acquisition circuit; acquires the second sampling voltage and compares the difference between the second bias voltage and the second sampling voltage with whether it is within a preset second error range. If it is within the preset second error range, the sensor power supply and voltage acquisition circuit is normal; if it is not within the preset second error range, the sensor power supply and voltage acquisition circuit is abnormal; receives digital signals and second digital signals and transmits the digital signals and second digital signals to the network port.

[0028] Network port: Receives digital signals and second digital signals, and transmits the received digital signals and second digital signals to the host computer; receives control commands sent by the host computer, parses the control commands, and if the control command is a solenoid valve acquisition command, transmits the solenoid valve acquisition command to the solenoid valve current acquisition board; if the control command is a sensor acquisition command, transmits the sensor acquisition command to the second MCU.

[0029] The sensor voltage acquisition board can be functionally divided into a second DC / DC power supply module, a sensor power supply and voltage acquisition circuit, a second MCU and peripheral circuits, a memory, and a network port. The DC-DC power supply circuit converts the 27V DC voltage to the DC voltage required by the sensor voltage acquisition board, such as +5V or +3.3V. The sensor voltage acquisition circuit isolates the acquired voltage value, uses an operational amplifier and an ADC to convert it into a digital signal, and sends it to the MCU. The MCU sets the bias voltage through its internal DAC. When there is no external input, it can check whether the self-test channel function is normal by comparing the difference between the bias voltage and the sampled voltage. The MCU and peripheral circuits ensure the normal operation of the MCU. The MCU parses the instructions sent by the host computer through the network port. When the instruction is to acquire sensor data, it periodically packages and uploads the sensor data. When the instruction is to acquire solenoid valve data, it receives the current data from the solenoid valve acquisition board and uploads the data to the host computer through the network port.

[0030] A reverse peak suppression circuit was added to the solenoid valve power supply circuit to reduce the reverse electromotive force generated when the solenoid valve is turned off; a short-circuit protection design was added to the 220VAC power input terminal to ensure test safety; isolation amplifiers were used for the current sampling circuit and subsequent signal processing circuit to prevent the tested circuit from affecting the test instrument; a self-test circuit was added to enable channel self-testing when the solenoid valve is not connected to the test instrument; a digital filtering algorithm was used for the sampled data to increase the solenoid valve current sampling frequency to 10KHz with a measurement error of <0.5%; the sensor voltage was simultaneously acquired from 12 channels with a sampling frequency of 112Hz and a measurement error of <0.01%; a transformer isolation design was implemented using GST5009 to effectively prevent external interference from affecting the internal circuitry of the test instrument.

[0031] The host computer software for the testing instrument is designed using LabVIEW and mainly implements the following functions: ① Controlling the energization and de-energization of 28 solenoid valves and 12 pressure sensors; ② Storing the solenoid valve energization and de-energization commands, and recording solenoid valve current data and pressure sensor data. Through timing input of the testing process, a one-click engine testing function is achieved; defining the solenoid valve current curve interpretation nodes enables automatic data reading and interpretation; adding sensor channel formula and criterion input functions enables automatic test data interpretation; in the data viewing interface, data to be viewed can be selected from the database, and the data can be manually interpreted and compared, generating test reports; to prevent accidental operation, the software incorporates an interlock function for the switch buttons and adds a confirmation pop-up interface.

[0032] The lower-level computer of the tester uses C language. The software runtime environment is a microcontroller system consisting of an HWD32F407 microcontroller, a DP83848I Ethernet port circuit, memory, and peripheral circuits. The development environment is Keil uVision For ARM. Its main functions include: ① Correctly executing instructions from the upper-level computer. Based on the instructions from the upper-level computer, it controls the on / off state of the optocoupler through the microcontroller's I / O ports, indirectly controlling the on / off state of the MOSFET to achieve power supply control; ② Acquiring and converting the solenoid valve operating current signal and the pressure sensor pressure signal through the microcontroller's built-in ADC; ③ Setting the self-test voltage through the microcontroller's built-in DAC; ④ Sending the measured data to the upper-level computer via Ethernet for data processing and interpretation, and receiving control signals from the upper-level computer.

[0033] After the host computer of the integrated engine tester is turned on, a memory check will automatically pop up. Enter the test configuration interface and fill in information such as operator, test location, task number, equipment number, temperature, etc. The integrated engine tester mainly realizes six functions: self-test, data viewing, verification, sensor formula binding, sensor power-on test, and real-time acquisition and monitoring.

[0034] like Figure 1As shown, the integrated engine tester has self-testing, calibration, control acquisition, and data playback functions. The integrated tester connects to the engine via a tooling cable. An AC / DC power conversion circuit converts AC220V power to +27V and +15V power to supply the engine's solenoid valves and pressure sensors. A DC / DC power conversion circuit converts the +15V power to +3.3V, +5V, and 3V. The host computer issues commands to the slave computer (i.e., the integrated engine tester) via a microprocessor. The slave computer controls the on / off state of 28 engine solenoid valves via a solenoid valve power supply control circuit and collects and converts the current signals through a solenoid valve operating current measurement circuit. The pressure sensor pressure measurement circuit collects and converts the pressure signals output by the engine's 12 pressure sensors. The solenoid valve current and pressure signals undergo ADC conversion and data processing by the microprocessor, communicate with the host computer via a network interface, and transmit the data to the host computer for storage. The host computer processes the voltage signals using software and plots them as curves for analysis and interpretation.

[0035] like Figure 2 As shown, the solenoid valve power supply control circuit includes resistors R1 and R2, optocoupler B1, R3 and R4, diode V1, PNP transistor V2, diode V3, N-MOSFET V4, and resistor R5. The positive terminal of resistor R1 is connected to the digital voltage VCC1, and the negative terminal of resistor R1 is connected to the MCU control I / O port DZ and the negative terminal of the light-emitting side of optocoupler B1. The negative terminal of resistor R2 is connected to the positive terminal of the light-emitting side of optocoupler B1. The positive terminal of the photosensitive side of optocoupler B1 is connected to the positive terminal of resistor R3, the positive terminal of diode V1, and the base of PNP transistor V2. The negative terminal of the photosensitive side of optocoupler B1 is connected to the negative terminal of resistor R3, the positive terminal of resistor R4, the negative terminal of diode V3, and the source of N-MOSFET V4. The negative terminal of diode V1 is connected to the emitter of transistor V2 and the N-MOSFET V4. The gate of V4; the collector of transistor V2 is connected to the negative terminal of resistor R4; the supply voltage DCY_P is connected to the drain of N-MOSFET V4; the positive terminal of diode V3 is connected to the positive terminal of resistor R5, and the negative terminal of resistor R5 is connected to ground B- of the current sampling circuit of the current measuring valve.

[0036] When the MCU I / O port DZ is low, the optocoupler's light-emitting side is turned on, and the output voltage is higher than the threshold voltage of N-MOSFET V4. N-MOSFET V4 is turned on, and the supply voltage DCY_P is connected to the solenoid valve's power supply output DCF. When the MCU I / O port DZ is high, the optocoupler's light-emitting side is turned off, N-MOSFET V4 is turned off, and the supply voltage DCY_P is disconnected from the solenoid valve's power supply output DCF.

[0037] Because N-MOSFET V4 has parasitic capacitance, when switching from conduction to turn-off, the output of optocoupler B1 goes low, but the voltage between the gate and source of N-MOSFET V4 does not change immediately, but decreases slowly. To improve the turn-off speed of N-MOSFET V4, diode V2 and resistor R4 are used to form a fast discharge channel. When the output of optocoupler B1 goes low, there is a voltage difference between the emitter and base and between the emitter and collector of transistor V2. Transistor V2 operates, providing a fast discharge channel for the gate and source of N-MOSFET V4, accelerating the MOSFET's turn-off. The solenoid valve is an inductive load, which generates a reverse electromotive force at the moment of power failure. Therefore, a reverse peak suppression circuit composed of V3 and R5 is set at the power output of the solenoid valve.

[0038] like Figure 3As shown, the solenoid valve current acquisition circuit includes a first voltage divider resistor R6, a first differential resistor R7, a second differential resistor R8, a third differential resistor R9, a fourth differential resistor R10, a fifth differential resistor R11, a sixth differential resistor R12, a first isolation operational amplifier N1, a second operational amplifier N2, capacitors C1, C2, C3, and C4. The positive terminal of the first voltage divider resistor R6 is connected to the negative terminal DCF_-B of the solenoid valve and the positive terminal of the first differential resistor R7. The negative terminal of the first voltage divider resistor R6 is connected to the solenoid valve power supply ground -B and the second differential resistor R7. The positive terminal of R8; the negative terminal of the first differential resistor R7 is connected to the positive input terminal of the first isolation operational amplifier N1, and the negative terminal of the second differential resistor R8 is connected to the negative input terminal of the first isolation operational amplifier N1; one end of capacitor C1 is connected to the positive input terminal of the first isolation operational amplifier N1, and the other end of capacitor C1 is connected to the negative input terminal of the first isolation operational amplifier N1; the input power supply terminal of the first isolation operational amplifier N1 is connected to the analog voltage VCC2, and the input ground terminal of the first isolation operational amplifier N1 is connected to the solenoid valve power supply ground -B; the isolated output power supply terminal of the first isolation operational amplifier N1 is connected to the analog voltage VCC2. The analog voltage VCC3 and one end of capacitor C3 are connected, and the other end of capacitor C3 is connected to analog ground AGND. The output ground of the first isolation operational amplifier N1 is connected to analog ground AGND. The positive output terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the third differential resistor R9, and the negative output terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the fourth differential resistor R10. The negative terminal of the third differential resistor R9 is connected to the non-inverting input of the second operational amplifier N2, and the negative terminal of the fourth differential resistor R10 is connected to the inverting input of the second operational amplifier N2. The positive terminal of the fifth differential resistor R11 is connected to the second operational amplifier N2. The positive gain terminal of the second operational amplifier N2 is connected to the negative gain terminal of the fifth differential resistor R11. The positive terminal of the sixth differential resistor R12 is connected to the output terminal of the second operational amplifier N2. The negative terminal of the sixth differential resistor R12 is connected to the ADC voltage acquisition terminal DCFAI and one end of capacitor C3. The other end of capacitor C3 is connected to analog ground AGND. The bias terminal of the second operational amplifier N2 is connected to the built-in DAC interface VREF_DCF of the MCU. One end of capacitor C2 is connected to the non-inverting terminal of the second operational amplifier N2, and the other end of capacitor C2 is connected to the inverting terminal of the second operational amplifier N2.

[0039] like Figure 4As shown, the sensor power supply and voltage acquisition circuit includes diode V5, resistors R13, R14, R15, R16, R17, R18, isolation operational amplifier N3, operational amplifier N4, capacitors C5, C6, C7, C8, C9, C10, C11, C12, and C13. The positive terminal of diode V5 is connected to the pressure sensor output voltage YLZ and the positive terminal of resistor R13, while the negative terminal of diode V5 is connected to YLGND. The negative terminal of resistor R13 is connected to the positive terminal of resistor R14 and capacitor C12. One end of resistor R5 is connected to the non-inverting input of isolation operational amplifier N3; the negative end of resistor R14, the other ends of capacitors C5, C6, C7, and C8, and the input ground of isolation operational amplifier N3 are all connected to the pressure sensor ground YLGND; the positive terminal of the differential output of isolation operational amplifier N3 is connected to the positive terminal of resistor R15, and the negative terminal of resistor R15 and one end of capacitor C11 are both connected to the non-inverting input of operational amplifier N4; the negative terminal of the differential output of isolation amplifier N3 is connected to the positive terminal of resistor R16, and the negative terminal of resistor R16 and the other end of capacitor C11 are both connected to the operational amplifier... The inverting input terminal of operational amplifier N4 is connected to the inverting input terminal; the positive terminal of resistor R17 is connected to the positive gain input terminal of operational amplifier N4, and the negative terminal of resistor R17 is connected to the negative gain input terminal of operational amplifier N4; the output terminal of operational amplifier N4 is connected to the positive terminal of resistor R18, the negative terminal of resistor R18 and one end of capacitor C13 are both connected to the ADC voltage acquisition interface ADC_YL, and the other end of capacitor C13 is connected to analog ground AGND1; the bias terminal of operational amplifier N4 is connected to the MCU built-in DAC interface VREF_YL; the isolated output power supply terminal of operational amplifier N4 is connected to analog voltage VCC5 and one end of capacitor C12 respectively. One end of capacitor C12 is connected to analog ground AGND1, and the output ground of operational amplifier N4 is connected to analog ground AGND1; one end of capacitor C6, one end of capacitor C7, and the VDD1 terminal of isolation operational amplifier N3 are all connected to analog voltage VCC4; one end of capacitor C8 is connected to the VCAP terminal of isolation operational amplifier N3; the VDD2 terminal of isolation operational amplifier N3, one end of capacitor C9, and one end of capacitor C10 are all connected to analog voltage VCC5; the GND2 terminal of isolation operational amplifier N3, the other end of capacitor C9, and the other end of capacitor C10 are all connected to analog ground AGND1.

[0040] This embodiment enables the integrated tester to simultaneously meet the requirements of engine solenoid valve action testing, solenoid valve curve recording, and telemetry pressure recording. It also features a redesigned human-machine interface to improve user-friendliness and equipment sampling accuracy. Furthermore, it adds automatic data interpretation and storage functions, as well as solenoid valve linkage testing functions, allowing for automatic engine testing and interpretation, thus significantly optimizing the testing process.

[0041] This embodiment makes the tester highly integrated, miniaturized, and lightweight; it adopts a digital filtering algorithm to improve the test accuracy and sampling rate, increasing the current sampling frequency of the solenoid valve to 10kHz, with a current measurement error of <0.5%; and a pressure sensor measurement error of <0.01%.

[0042] This embodiment optimizes the host computer software to achieve solenoid valve linkage timing control, adds anti-accidental touch design, and improves test safety; optimizes the self-test function, enabling the tester to independently test the circuit, reducing the tester's self-test work and improving efficiency; adds automatic interpretation and linkage test functions to the host computer, greatly optimizing the engine test process; and optimizes the data viewing function, allowing for comparative analysis of test data and generation of test reports.

[0043] To improve testing safety, this embodiment adds a short-circuit protection design to the 220VAC power input terminal and adds a reverse peak suppression circuit to the solenoid valve power supply circuit.

[0044] The chassis in this embodiment contains a high-power control circuit, which is prone to electromagnetic interference. Interference is eliminated and test reliability is improved by isolating the solenoid valve operating current sampling circuit from the signal processing circuit, and by shielding and filtering designs. A high-precision current sensor is connected to the solenoid valve operating circuit to detect the solenoid valve operating current, thereby improving the sampling accuracy of the solenoid valve operating current and increasing the sampling time from 50ms to 100ms.

[0045] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. An integrated test instrument for cryogenic liquid rocket engines, characterized in that... include: AC / DC power supply module, solenoid valve current acquisition board, sensor voltage acquisition board, and host computer; among them... The AC / DC power module receives 220V AC voltage, converts 220V AC voltage into +15V DC voltage and +27V DC voltage, provides +27V DC voltage to the solenoid valve current acquisition board and the sensor voltage acquisition board respectively, and provides +15V DC voltage to the sensor voltage acquisition board. The solenoid valve current acquisition board: receives +27V DC voltage and converts it into a preset DC voltage; receives and acquires solenoid valve commands, generates MCU control signals, and controls the power supply to and from the solenoid valve according to the MCU control signals; acquires the solenoid valve operating current signal, converts it into a voltage signal, converts the voltage signal into a digital signal via an ADC, and transmits the digital signal to the sensor voltage acquisition board; sets a bias voltage and checks whether the self-test channel function is normal by comparing the difference between the bias voltage and the sampled voltage. The sensor voltage acquisition board: receives +15V DC voltage and +27V DC voltage, converts the +27V DC voltage into a preset DC voltage; receives control commands, parses the control commands, if the control command is a solenoid valve acquisition command, transmits the solenoid valve acquisition command to the solenoid valve current acquisition board, if the control command is a sensor acquisition command, generates a second MCU control signal; acquires voltage values ​​according to the second MCU control signal, processes the voltage values ​​to obtain a second digital signal, and transmits the second digital signal to the host computer; sets a second bias voltage, and checks whether the self-test channel function is normal by comparing the difference between the second bias voltage and the second sampled voltage; The host computer sends control commands to the sensor voltage acquisition board.

2. The cryogenic liquid rocket engine integrated test instrument according to claim 1, characterized in that: The solenoid valve current acquisition board includes a first DC / DC power supply module, a solenoid valve power supply control circuit, a solenoid valve current acquisition circuit, and a first MCU; wherein... The first DC / DC power module receives a +27V DC voltage, converts the +27V DC voltage into a +5V DC voltage and a +3.3V DC voltage, supplies the +5V DC voltage to the solenoid valve current acquisition circuit, and supplies the +3.3V DC voltage to the first MCU. The solenoid valve power supply control circuit: receives +27V DC voltage; receives MCU control signals, and controls the solenoid valve power supply on and off according to the MCU control signals; The solenoid valve current acquisition circuit acquires the solenoid valve operating current signal, converts the solenoid valve operating current signal into a voltage signal, converts the voltage signal into a digital signal via an ADC, and transmits the digital signal to the first MCU; when there is no external input, it receives the bias voltage, processes the bias voltage to obtain the sampling voltage, and transmits the sampling voltage to the first MCU. The first MCU: receives the solenoid valve command, generates an MCU control signal, and transmits the MCU control signal to the solenoid valve power supply control circuit; generates a bias voltage and transmits the bias voltage to the solenoid valve power supply control circuit; acquires the feedback voltage, compares the difference between the bias voltage and the feedback voltage to see if it is within a preset error range. If it is within the preset error range, the solenoid valve current acquisition circuit is normal; if it is not within the preset error range, the solenoid valve current acquisition circuit is abnormal; receives digital signals and transmits the digital signals to the sensor voltage acquisition board.

3. The cryogenic liquid rocket engine integrated test instrument according to claim 1, characterized in that: The sensor voltage acquisition board includes a second DC / DC power supply module, a sensor power supply and voltage acquisition circuit, a second MCU, and a network port; wherein... The second DC / DC power module receives a +27V DC voltage, converts the +27V DC voltage into a +5V DC voltage and a +3.3V DC voltage, supplies the +5V DC voltage to the network port, and supplies the +3.3V DC voltage to the second MCU; The sensor power supply and voltage acquisition circuit: receives +27V DC voltage; receives a second MCU control signal, acquires voltage value according to the second MCU control signal, processes the voltage value to obtain a second digital signal, and transmits the second digital signal to the second MCU; when there is no external input, receives a second bias voltage, processes the second bias voltage to obtain a second sampling voltage, and transmits the second sampling voltage to the second MCU. The second MCU: receives the sensor acquisition command, generates a second MCU control signal, and transmits the second MCU control signal to the sensor power supply and voltage acquisition circuit; generates a second bias voltage and transmits the bias voltage to the sensor power supply and voltage acquisition circuit; acquires a second sampling voltage, compares the difference between the second bias voltage and the second sampling voltage to see if it is within a preset second error range. If it is within the preset second error range, the sensor power supply and voltage acquisition circuit is normal; if it is not within the preset second error range, the sensor power supply and voltage acquisition circuit is abnormal; receives a digital signal and a second digital signal, and transmits the digital signal and the second digital signal to the network port. The network port: receives digital signals and second digital signals, and transmits the received digital signals and second digital signals to the host computer; receives control commands sent by the host computer, parses the control commands, and if the control command is a solenoid valve acquisition command, transmits the solenoid valve acquisition command to the solenoid valve current acquisition board; if the control command is a sensor acquisition command, transmits the sensor acquisition command to the second MCU.

4. The cryogenic liquid rocket engine integrated test instrument according to claim 2, characterized in that: The solenoid valve power supply control circuit includes resistors R1 and R2, optocoupler B1, resistors R3 and R4, diode V1, PNP transistor V2, diode V3, N-MOSFET V4, and resistor R5; wherein, The positive terminal of resistor R1 is connected to the digital voltage VCC1, and the negative terminal of resistor R1 is connected to the MCU control IO port DZ and the negative terminal of the light-emitting side of optocoupler B1, respectively. The negative terminal of resistor R2 is connected to the positive terminal of the light-emitting side of optocoupler B1. The positive terminal of the photosensitive side of the optocoupler B1 is connected to the positive terminal of resistor R3, the positive terminal of diode V1, and the base of PNP transistor V2, respectively. The negative terminal of the photosensitive side of the optocoupler B1 is connected to the negative terminal of resistor R3, the positive terminal of resistor R4, the negative terminal of diode V3, and the source of N-MOSFET V4, respectively. The negative terminal of diode V1 is connected to the emitter of transistor V2 and the gate of N-MOSFET V4, respectively; The collector of transistor V2 is connected to the negative terminal of resistor R4; The power supply voltage DCY_P is connected to the drain of N-MOSFET V4; The positive terminal of diode V3 is connected to the positive terminal of resistor R5, and the negative terminal of resistor R5 is connected to ground B- of the current sampling circuit of the electrical measuring valve.

5. The integrated test instrument for cryogenic liquid rocket engines according to claim 2, characterized in that: The solenoid valve current acquisition circuit includes a first voltage divider resistor R6, a first differential resistor R7, a second differential resistor R8, a third differential resistor R9, a fourth differential resistor R10, a fifth differential resistor R11, a sixth differential resistor R12, a first isolation operational amplifier N1, a second operational amplifier N2, capacitors C1, C2, C3, and C4; wherein, The positive terminal of the first voltage divider resistor R6 is connected to the negative terminal DCF_-B of the solenoid valve and the positive terminal of the first differential resistor R7, respectively. The negative terminal of the first voltage divider resistor R6 is connected to the power supply ground -B of the solenoid valve and the positive terminal of the second differential resistor R8. The negative terminal of the first differential resistor R7 is connected to the positive input terminal of the first isolation operational amplifier N1, and the negative terminal of the second differential resistor R8 is connected to the negative input terminal of the first isolation operational amplifier N1. One end of the capacitor C1 is connected to the positive input terminal of the first isolation operational amplifier N1, and the other end of the capacitor C1 is connected to the negative input terminal of the first isolation operational amplifier N1. The input power supply terminal of the first isolated operational amplifier N1 is connected to the analog voltage VCC2, and the input ground terminal of the first isolated operational amplifier N1 is connected to the power supply ground of the solenoid valve -B. The isolated output power supply terminal of the first isolated operational amplifier N1 is connected to the analog voltage VCC3 and one end of the capacitor C3, respectively. The other end of the capacitor C3 is connected to the analog ground AGND. The output ground terminal of the first isolated operational amplifier N1 is connected to the analog ground AGND. The positive output terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the third differential resistor R9, and the negative output terminal of the first isolation operational amplifier N1 is connected to the positive terminal of the fourth differential resistor R10. The negative terminal of the third differential resistor R9 is connected to the non-inverting input of the second operational amplifier N2; the negative terminal of the fourth differential resistor R10 is connected to the inverting input of the second operational amplifier N2; the positive terminal of the fifth differential resistor R11 is connected to the positive gain input of the second operational amplifier N2; the negative terminal of the fifth differential resistor R11 is connected to the negative gain input of the second operational amplifier N2; the positive terminal of the sixth differential resistor R12 is connected to the output terminal of the second operational amplifier N2; the negative terminal of the sixth differential resistor R12 is connected to the ADC voltage acquisition terminal DCFAI and one end of capacitor C3; the other end of capacitor C3 is connected to analog ground AGND; and the bias terminal of the second operational amplifier N2 is connected to the MCU built-in DAC interface VREF_DCF. One end of capacitor C2 is connected to the non-inverting input of the second operational amplifier N2, and the other end of capacitor C2 is connected to the inverting input of the second operational amplifier N2.

6. The integrated test instrument for cryogenic liquid rocket engines according to claim 3, characterized in that: The sensor power supply and voltage acquisition circuit includes diode V5, resistors R13, R14, R15, R16, R17, and R18, isolation operational amplifier N3, operational amplifier N4, capacitors C5, C6, C7, C8, C9, C10, C11, C12, and C13; wherein, The positive terminal of the diode V5 is connected to the output voltage YLZ of the pressure sensor and the positive terminal of the resistor R13, respectively. The negative terminal of diode V5 is connected to YLGND; The negative terminal of resistor R13 is connected to the positive terminal of resistor R14, one end of capacitor C5, and the non-inverting input terminal of isolation operational amplifier N3, respectively. The negative terminal of resistor R14, the other end of capacitor C5, the other end of capacitor C6, the other end of capacitor C7, the other end of capacitor C8, and the input ground terminal of isolation operational amplifier N3 are all connected to the pressure sensor ground YLGND. The positive terminal of the differential output of the isolation operational amplifier N3 is connected to the positive terminal of the resistor R15, and the negative terminal of the resistor R15 and one end of the capacitor C11 are both connected to the non-inverting input terminal of the operational amplifier N4. The negative terminal of the differential output of the isolation amplifier N3 is connected to the positive terminal of the resistor R16, and the negative terminal of the resistor R16 and the other end of the capacitor C11 are both connected to the inverting input terminal of the operational amplifier N4. The positive terminal of resistor R17 is connected to the positive gain input terminal of operational amplifier N4, and the negative terminal of resistor R17 is connected to the negative gain input terminal of operational amplifier N4. The output terminal of the operational amplifier N4 is connected to the positive terminal of the resistor R18. The negative terminal of the resistor R18 and one end of the capacitor C13 are both connected to the ADC voltage acquisition interface ADC_YL, and the other end of the capacitor C13 is connected to the analog ground AGND1. The bias terminal of the operational amplifier N4 is connected to the built-in DAC interface VREF_YL of the MCU; The isolated output power supply terminal of the operational amplifier N4 is connected to the analog voltage VCC5 and one end of the capacitor C12, respectively. The other end of the capacitor C12 is connected to the analog ground AGND1, and the output ground terminal of the operational amplifier N4 is connected to the analog ground AGND1. One end of capacitor C6, one end of capacitor C7, and the VDD1 terminal of isolation operational amplifier N3 are all connected to analog voltage VCC4; One end of capacitor C8 is connected to the VCAP terminal of isolation operational amplifier N3; The VDD2 terminal of the isolation operational amplifier N3, one end of capacitor C9, and one end of capacitor C10 are all connected to the analog voltage VCC5; The GND2 terminal of the isolation operational amplifier N3, the other end of capacitor C9, and the other end of capacitor C10 are all connected to analog ground AGND1.

7. The cryogenic liquid rocket engine integrated test instrument according to claim 4, characterized in that: When the MCU control IO port DZ is low, the light-emitting side of optocoupler B1 is turned on, N-MOSFET V4 is turned on, and the power supply voltage DCY_P is connected to the power supply output DCF of the solenoid valve.

8. The cryogenic liquid rocket engine integrated test instrument according to claim 4, characterized in that: When the MCU control IO port DZ is high, the light-emitting side of optocoupler B1 is cut off, N-MOSFET V4 is cut off, and the power supply voltage DCY_P is disconnected from the power supply output DCF of the solenoid valve.

9. The cryogenic liquid rocket engine integrated test instrument according to claim 4, characterized in that: Because of the parasitic capacitance of N-MOSFET V4, when switching from on to off, the output of optocoupler B1 goes low, but the voltage of the gate and source of N-MOSFET V4 does not change immediately, but decreases slowly.

10. The cryogenic liquid rocket engine integrated test instrument according to claim 4, characterized in that: When the output of the photosensitive side of the optocoupler B1 goes low, there is a voltage difference between the emitter and base of the transistor V2 and between the emitter and collector. The transistor V2 operates, providing a fast discharge channel for the gate and source of the N-MOSFET V4, thus accelerating the turn-off of the N-MOSFET V4.

Images