Floating power supply micro-current acquisition device and method for space plasma detection

Abstract

The invention provides a floating power supply micro-current acquisition device and method for space plasma detection, relates to the technical field of plasma science and space detection, and aims to solve the problem that a space plasma environment causes satellite wide-range potential deviation. And high-precision stable acquisition of picoampere-level weak current signals under severe potential fluctuation cannot be realized. The device comprises a floating power supply circuit, a voltage follower circuit and a signal acquisition circuit which are connected in sequence, scanning voltage sequentially passes through a first high-voltage operational amplifier and a voltage dividing module which are connected in series in the floating power supply circuit; the voltage follower circuit comprises a second high-voltage operational amplifier and a third high-voltage operational amplifier which are connected in parallel, and transmits the generated power supply voltage to the signal acquisition circuit; the signal acquisition circuit comprises a current-voltage conversion circuit and a subtraction operation circuit which are connected in series, and converts current into voltage and suppresses high-frequency noise. The problems existing in the prior art are solved, and high-precision stable acquisition of picoampere-level weak current signals under severe potential fluctuation is realized.

Description

Technical Field

[0001] The present invention belongs to the field of plasma science and space detection technology, and in particular relates to a floating power supply micro-current acquisition device and method for space plasma detection. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] In the field of space plasma environment exploration, accurately measuring the parameters of low-energy charged particles is key to studying space physics processes such as magnetospheric dynamics and solar wind-magnetosphere coupling. Langmuir probes and ion detectors, core payloads for on-orbit exploration, collect real-time microcurrent signals generated by the interaction between the surface of a star and the surrounding plasma. Combined with IV characteristic curve analysis, these signals can reveal important parameters such as electron and ion density, and particle temperature.

[0004] However, satellites in orbit are subject to significant surface charging due to the space plasma environment, with potential shifts reaching as high as ±30V. This significantly impacts the signal acquisition circuits of the detection system directly coupled to the satellite itself. Traditional current acquisition systems use precision op amps powered by ±15V to construct transimpedance amplifier circuits. These limited supply voltage ranges easily enter a nonlinear operating region when encountering large potential excursions, leading to severe distortion or even complete failure of weak picoampere current signals. While high-voltage op amps can extend the power supply range, these devices inherently have high input bias currents that can overwhelm the signal being measured. This means that the insufficient power supply range of traditional low-voltage op amps can cause signal saturation, and high-voltage op amps can introduce input noise interference, making it difficult to address the wide-range potential shifts caused by the space plasma environment during satellite orbital operation.

[0005] In addition, although traditional isolated power supplies can achieve potential isolation through DC-DC conversion, they will introduce noise interference, resulting in data failure. Although monitoring the potential through ADC and performing digital correction improves the measurement effect to a certain extent, it is prone to data loss due to insufficient sampling rate. Summary of the Invention

[0006] To overcome the shortcomings of the above-mentioned existing technologies, the present invention provides a floating power supply microcurrent acquisition device and method for space plasma detection. By constructing a dynamic floating power supply architecture that is linked in real time with the satellite body potential, the problem of scanning voltage offset caused by satellite potential fluctuations in traditional solutions is solved. Combined with a current-voltage conversion circuit, stable signal acquisition and preliminary processing are achieved.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0008] A first aspect of the present invention provides a floating power supply micro-current acquisition device for space plasma detection, comprising:

[0009] A floating power supply circuit, a voltage follower circuit, and a signal acquisition circuit are connected in sequence;

[0010] The input end of the floating power supply circuit is connected to the circuit for generating the scanning voltage, and the scanning voltage is sequentially passed through the first high-voltage operational amplifier and the voltage divider module connected in series to output the first supply voltage and the second supply voltage, which are then input to the voltage follower circuit;

[0011] The voltage follower circuit includes a second high-voltage operational amplifier and a third high-voltage operational amplifier connected in parallel, which are respectively connected to the first power supply voltage and the second power supply voltage to obtain a first follower power supply voltage and a second follower power supply voltage, and transmit them to the signal acquisition circuit;

[0012] The signal acquisition circuit includes a current-voltage conversion circuit and a subtraction operation circuit connected in series. The input end is connected to the first follower power supply voltage and the second follower power supply voltage to provide power and voltage protection for the current-voltage conversion circuit. At the same time, the scanning voltage and the weak current signal output by the detector are input into the series current-voltage conversion circuit and the subtraction operation current in sequence to output the final voltage signal.

[0013] As an implementation manner, the non-inverting input terminal of the first high-voltage operational amplifier is connected to a circuit for generating a scan voltage, and the inverting input terminal is connected to an output terminal.

[0014] As an embodiment, the voltage divider module includes a resistor voltage divider network and a bipolar voltage stabilizing diode array;

[0015] The resistor voltage divider network includes a first resistor voltage divider network and a second resistor voltage divider network;

[0016] The bipolar zener diode array includes a first zener diode and a second zener diode;

[0017] The first resistor divider network and the first voltage stabilizing diode are connected in series, and then connected in parallel with the second resistor divider network and the second voltage stabilizing diode in series; the input end of the parallel connection is connected to the output end of the first high-voltage operational amplifier.

[0018] As an implementation method, the first resistor divider network includes a first resistor and a second resistor;

[0019] The second resistor divider network includes a third resistor and a fourth resistor;

[0020] One end of the first resistor is connected in series with the second resistor, and the other end is connected to the positive terminal of the DC voltage, and the second resistor is connected in series with the negative terminal of the first voltage stabilizing diode;

[0021] One end of the third resistor is connected in series with the fourth resistor, and the other end is connected to the negative terminal of the DC voltage. The third resistor is connected in series with the positive terminal of the second voltage stabilizing diode.

[0022] As an embodiment, the non-inverting input terminal of the second high-voltage operational amplifier is connected to the negative end of the first voltage-stabilizing diode; the second high-voltage operational amplifier is connected to the first high-voltage operational amplifier through the power supply terminal; and the output terminal of the second high-voltage operational amplifier outputs the first follower supply voltage.

[0023] As an embodiment, the non-inverting input terminal of the third high-voltage operational amplifier is connected to the positive terminal of the second voltage-stabilizing diode; the third high-voltage operational amplifier is connected to the first high-voltage operational amplifier through the power supply terminal; and the output terminal of the third high-voltage operational amplifier outputs the second follower supply voltage.

[0024] As an embodiment, the current-to-voltage conversion circuit includes a fourth low-voltage operational amplifier and a first first-order low-pass filter network;

[0025] The scanning voltage is input to the non-inverting input terminal of the fourth low-voltage operational amplifier; the inverting input terminal of the fourth low-voltage operational amplifier is connected to the detector;

[0026] The two power supply terminals of the fourth low-voltage operational amplifier are respectively connected to the output terminal of the second high-voltage operational amplifier and the output terminal of the third high-voltage operational amplifier;

[0027] The first first-order low-pass filter network includes a fifth resistor and a first capacitor connected in parallel, and two ends of the first first-order low-pass filter network are respectively connected to the inverting input terminal and the output terminal of the fourth low-voltage operational amplifier.

[0028] As an embodiment, the subtraction circuit includes a fifth high-voltage operational amplifier and a second first-order low-pass filter network;

[0029] The non-inverting input terminal of the fifth high-voltage operational amplifier is connected to the non-inverting input terminal of the fourth low-voltage operational amplifier through a sixth resistor; the inverting input terminal of the fifth high-voltage operational amplifier is connected to the output terminal of the fourth low-voltage operational amplifier through a seventh resistor;

[0030] The fifth high-voltage operational amplifier is connected to the first high-voltage operational amplifier, the second high-voltage operational amplifier and the third high-voltage operational amplifier through a power supply terminal;

[0031] The non-inverting input terminal of the fifth high-voltage operational amplifier is connected in series with the eighth resistor and grounded;

[0032] The second first-order low-pass filter network includes a ninth resistor and a second capacitor connected in parallel, and two ends of the second first-order low-pass filter network are respectively connected to the inverting input terminal and the output terminal of the fifth high-voltage operational amplifier.

[0033] A second aspect of the present invention provides a floating power supply microcurrent acquisition method for space plasma detection, comprising:

[0034] Inputting the acquired scanning voltage into a floating power supply circuit to output a stable first power supply voltage and a second power supply voltage;

[0035] Inputting the first power supply voltage and the second power supply voltage into the voltage follower circuit, outputting the first follower power supply voltage and the second follower power supply voltage, and supplying power to the signal acquisition circuit;

[0036] The signal acquisition circuit receives the scanning voltage and the weak current signal output by the detector, and converts the weak current output by the detector into a voltage signal through the current-voltage conversion circuit and the subtraction circuit, thereby suppressing high-frequency noise.

[0037] According to the relationship between the converted voltage signal and the scanning voltage, the weak current output by the detector is calculated.

[0038] As an implementation method, the weak current output by the detector is calculated as follows:

[0039]

[0040] Among them, i T is the weak current output by the detector, U O is the final voltage signal, and R is the resistance of the fifth resistor R5.

[0041] One or more of the above technical solutions have the following beneficial effects:

[0042] In this embodiment, a floating power supply microcurrent acquisition device is constructed, comprising a floating power supply circuit, a voltage follower circuit, and a signal acquisition circuit. The floating power supply circuit achieves real-time linkage with the satellite's potential, preventing load changes from affecting scanning voltage accuracy. The low output impedance of the op amp drives a large-capacity voltage regulator network. The voltage follower circuit provides a stable, low-impedance power supply for subsequent circuits, preventing power rail fluctuations caused by sudden load current changes. The signal acquisition circuit achieves current-to-voltage conversion and high-frequency noise suppression. This floating power supply microcurrent acquisition device overcomes the existing problem of scanning voltage offset caused by satellite potential fluctuations, enabling stable acquisition of weak floating power supply signals for space plasma detection.

[0043] In this embodiment, a dynamic floating power supply circuit that is linked to the potential of the satellite body in real time is constructed, which solves the problem that the traditional isolated power supply circuit is easily affected by noise and causes data failure.

[0044] In this embodiment, four high-voltage operational amplifiers and one low-voltage operational amplifier cooperate with each other, which not only improves the measurement effect but also overcomes the problem of insufficient sampling rate and easy data loss in the prior art.

[0045] Advantages of additional aspects of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The accompanying drawings, which constitute a part of the present invention, are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0047] Figure 1 This is a structural diagram of a floating power supply micro-current acquisition device for space plasma detection according to the first embodiment of the present invention;

[0048] Figure 2 This is a flow chart of the floating power supply micro-current acquisition method for space plasma detection according to the second embodiment;

[0049] Figure 3 The simulation circuit and simulation results of the floating power supply micro-current acquisition device for space plasma detection in the first embodiment;

[0050] Figure 4 This is the oscilloscope simulation waveform of the simulation circuit of the first embodiment;

[0051] Figure 5 The waveforms of the scanning voltage and the floating power supply voltage in the actual test of the floating power supply micro-current acquisition device for space plasma detection of the first embodiment are shown. DETAILED DESCRIPTION

[0052] It should be noted that the following detailed descriptions are exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present invention belongs.

[0053] It should be noted that the terms used herein are for describing particular embodiments only and are not intended to limit the exemplary embodiments according to the present invention.

[0054] In the absence of conflict, the embodiments of the present invention and the features thereof may be combined with each other.

[0055] Example 1

[0056] In the field of space plasma environment detection, there are several parallel space plasma detectors. The first end of each space plasma detector is arranged in the plasma of the ionosphere, and the second end of each space plasma detector is connected to the signal acquisition circuit. The signal acquisition circuit is connected to the circuit that generates the scanning voltage to collect and detect the weak current signal output by the detector.

[0057] However, when a satellite is in orbit, the space plasma environment causes wide-range potential offsets, making it impossible to achieve high-precision and stable acquisition of weak floating power supply signals for space plasma detection. This embodiment proposes a floating power supply micro-current acquisition device suitable for space plasma detectors. The device constructs a floating power supply micro-current acquisition device including a floating power supply circuit, a voltage follower circuit, and a signal acquisition circuit. This device overcomes the bottleneck of traditional low-voltage operational amplifiers, which have limited power supply range and lead to signal saturation when the satellite potential offsets. At the same time, it avoids the interference of high-voltage operational amplifier input noise and bias current on the collected weak current, and can achieve high-precision and stable acquisition of picoampere-level weak current signals under severe potential fluctuations. Through the dynamic tracking characteristics of the floating power supply, the precision operational amplifier always operates in the linear range.

[0058] Here we take the acquisition and detection of a weak current signal output by a detector as an example.

[0059] like Figure 1 As shown, this embodiment provides a floating power supply micro-current acquisition device for space plasma detection, comprising:

[0060] A floating power supply circuit, a voltage follower circuit, and a signal acquisition circuit are connected in sequence;

[0061] The input end of the floating power supply circuit is connected to the circuit for generating the scanning voltage, and the scanning voltage is sequentially passed through the first high-voltage operational amplifier and the voltage divider module connected in series to output the first supply voltage and the second supply voltage, which are then input to the voltage follower circuit;

[0062] The voltage follower circuit includes a second high-voltage operational amplifier and a third high-voltage operational amplifier connected in parallel, which are respectively connected to the first power supply voltage and the second power supply voltage to obtain a first follower power supply voltage and a second follower power supply voltage, and transmit them to the signal acquisition circuit;

[0063] The signal acquisition circuit includes a current-voltage conversion circuit and a subtraction operation circuit connected in series. The input end is connected to the first follower power supply voltage and the second follower power supply voltage to provide power and voltage protection for the current-voltage conversion circuit. At the same time, the scanning voltage and the weak current signal output by the detector are input into the series current-voltage conversion circuit and the subtraction operation current in sequence to output the final voltage signal.

[0064] In this embodiment, the Langmuir probe load is based on the satellite potential to load the scanning voltage V R ,Constructing a dynamic floating power supply circuit can be linked with the satellite potential in real time, and respond to changes in the satellite potential in real time.

[0065] The floating power supply acquisition device in this embodiment can acquire and detect weak current signals output by multiple detectors.

[0066] like Figure 1 As shown, in this embodiment, the floating power supply circuit includes a first high-voltage operational amplifier U1 and a voltage divider module.

[0067] In this embodiment, the non-inverting input terminal of the first high-voltage operational amplifier U1 is connected to the circuit generating the scanning voltage, and the inverting input terminal is connected to the output terminal, for isolating the scanning voltage generating circuit from the subsequent voltage regulator network.

[0068] Furthermore, the circuit for generating the scanning voltage is a circuit including a DA module, which is used to output the scanning voltage V R .

[0069] In this embodiment, the voltage divider module includes a high-precision resistor voltage divider network and a bipolar voltage regulator diode array.

[0070] The resistor divider network uses 1% precision metal film resistors to achieve voltage proportional distribution, and the voltage stabilizing diode array forms a ±15V reference offset through the voltage stabilizing diode series combination. R When the voltage fluctuates within the range of ±30V, the voltage drop is maintained at ±15V by the voltage stabilizing diode, generating a voltage drop of V R A symmetrical power rail centered on the

[0071] Furthermore, the resistor voltage divider network is divided into a first resistor voltage divider network and a second resistor voltage divider network.

[0072] The bipolar Zener diode array includes a first Zener diode D1 and a second Zener diode D2.

[0073] The first resistor divider network and the first voltage stabilizing diode D1 are connected in series, and then connected in parallel with the second resistor divider network and the second voltage stabilizing diode D2 in series; the input end of the parallel connection is connected to the output end of the first high-voltage operational amplifier U1.

[0074] Furthermore, the first resistor divider network includes a first resistor R1 and a second resistor R2.

[0075] The second resistor divider network includes a third resistor R3 and a fourth resistor R4.

[0076] One end of the first resistor R1 is connected in series with the second resistor R2, and the other end is connected to the positive terminal of the DC voltage. The second resistor R2 is connected in series with the negative terminal of the first voltage stabilizing diode D1, so as to realize proportional voltage distribution;

[0077] One end of the third resistor R3 is connected in series with the fourth resistor R4, and the other end is connected to the negative end of the DC voltage. The third resistor R3 is connected in series with the positive end of the second voltage stabilizing diode D2 to achieve proportional voltage distribution.

[0078] The DC voltage is ±70V. In the first resistor divider network, the voltage is proportionally distributed through the first resistor R1 and the second resistor R2. In the second resistor divider network, the voltage is proportionally distributed through the first resistor R3 and the second resistor R4, so that the Zener diodes D1 and D2 maintain a stable voltage drop of ±15V.

[0079] Specifically, the circuit including the DA module generates a scan voltage V R , through the first high voltage operational amplifier U1, V R The output is directly sent to the middle node of the 15V Zener diode (D1-D2), isolating the front-stage scanning voltage generation circuit from the rear-stage Zener diode network to prevent load changes from affecting the scanning voltage accuracy; the large-capacity Zener diode network is driven by the low output impedance of the first high-voltage operational amplifier U1; when the scanning voltage fluctuates, the voltage is proportionally distributed through the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, and the Zener diode maintains a stable voltage drop of ±15V.

[0080] like Figure 1 As shown, in this embodiment, the voltage follower circuit includes a second high-voltage operational amplifier U2 and a third high-voltage operational amplifier U3 connected in parallel.

[0081] In this embodiment, the non-inverting input terminal of the second high-voltage operational amplifier U2 is connected to the negative terminal of the first voltage stabilizing diode D1; the second high-voltage operational amplifier U2 is connected to the first high-voltage operational amplifier U1 through the power supply terminal; the output terminal of the second high-voltage operational amplifier U2 outputs the first follower supply voltage.

[0082] In this embodiment, the non-inverting input terminal of the third high-voltage operational amplifier U3 is connected to the positive terminal of the second voltage-stabilizing diode D2; the third high-voltage operational amplifier U3 is connected to the first high-voltage operational amplifier U1 through the power supply terminal; the output terminal of the third high-voltage operational amplifier U3 outputs the second follower supply voltage.

[0083] Furthermore, two sets of high-voltage operational amplifiers (U2-U3) are used to form a voltage follower to avoid power rail fluctuations caused by sudden changes in load current. The relationship between the received power supply voltage and the scan voltage is expressed as follows:

[0084] V + =VR +V offset (1)

[0085] V - =V R -V offset (2)

[0086] Among them, V + and V - are the first power supply voltage and the second power supply voltage, V R is the scan voltage, V Offset is the voltage drop of the Zener diode.

[0087] The output first follower power supply voltage and the second follower power supply voltage are the same as the first power supply voltage and the second power supply voltage, that is, the first follower power supply voltage output from the output end of the second high-voltage operational amplifier U2 is V + The second follower supply voltage outputted from the output terminal of the third high voltage operational amplifier U3 is V - .

[0088] A voltage follower is used to provide a low-impedance power supply for the low-voltage operational amplifier U4 of the subsequent transimpedance amplifier to avoid fluctuations in the power supply rail due to sudden changes in load current.

[0089] like Figure 1 As shown, in this embodiment, the signal acquisition circuit includes a current-voltage conversion circuit and a subtraction circuit.

[0090] The current-to-voltage conversion circuit, based on a transimpedance amplifier architecture, converts the detector's weak current signal into a high-precision voltage signal. The subtraction circuit eliminates the coupling interference of the scan bias voltage on the microcurrent signal through mathematical operations.

[0091] In this embodiment, the current-voltage conversion circuit includes a fourth low-voltage operational amplifier U4 and a first first-order low-pass filter network.

[0092] Furthermore, the scanning voltage V is input to the non-inverting input terminal of the fourth low voltage operational amplifier U4. R The inverting input terminal of the fourth low-voltage operational amplifier U4 is connected to the detector to receive the current signal of the picoampere to microampere level output by the detector.

[0093] The two power supply terminals of the fourth low voltage operational amplifier U4 are respectively connected to the output terminal of the second high voltage operational amplifier U2 and the output terminal of the third high voltage operational amplifier U3, and receive the first follower supply voltage V + and the second follower supply voltage V - , used to provide a stable low-impedance power supply for the fourth low-voltage operational amplifier U4.

[0094] Furthermore, the first first-order low-pass filter network includes a fifth resistor R5 and a first capacitor C1 connected in parallel, and both ends of the first first-order low-pass filter network are respectively connected to the inverting input and output of the fourth low-voltage operational amplifier U4.

[0095] In the negative feedback loop, the high-resistance metal film resistor R5 and the low-dielectric absorption capacitor C1 are connected in parallel to form a first-order low-pass filter network to achieve current-to-voltage conversion and high-frequency noise suppression.

[0096] In this embodiment, the subtraction circuit includes a fifth high-voltage operational amplifier U5 and a second first-order low-pass filter network.

[0097] The core architecture of the subtraction circuit is to build a differential amplifier topology based on the high-voltage operational amplifier U5, and realize the subtraction function by configuring the resistance ratio of the peripheral resistor network, that is, the second first-order low-pass filter network.

[0098] Furthermore, the non-inverting input terminal of the fifth high-voltage operational amplifier U5 is connected to the non-inverting input terminal of the fourth low-voltage operational amplifier U4 through the sixth resistor R6 to receive the scanning voltage V R The inverting input terminal of the fifth high-voltage operational amplifier U5 is connected to the output terminal of the fourth low-voltage operational amplifier U4 through the seventh resistor R7, receives the conversion voltage output by the fourth low-voltage operational amplifier U4, and outputs the compensated voltage using the differential amplification principle.

[0099] The fifth high-voltage operational amplifier U5 is connected to the first high-voltage operational amplifier U1 , the second high-voltage operational amplifier U2 , and the third high-voltage operational amplifier U3 through the power supply terminal to realize power supply for the fifth high-voltage operational amplifier U5 .

[0100] The non-inverting input terminal of the fifth high-voltage operational amplifier U5 is connected in series with the eighth resistor R8 and grounded, so that the two input terminals of the fifth high-voltage operational amplifier U5 are highly symmetrical, so that it has excellent common-mode rejection capability.

[0101] Furthermore, the second first-order low-pass filter network includes a ninth resistor R9 and a second capacitor C2 connected in parallel. Two ends of the second first-order low-pass filter network are respectively connected to the inverting input and output of the fifth high-voltage operational amplifier U5.

[0102] A differential amplifier topology is constructed based on the fifth high-voltage operational amplifier U5, and the subtraction function is realized by configuring the resistance ratio of the second first-order low-pass filter network. The compensated voltage is output using the differential amplifier principle. The final voltage signal U is obtained. O , the relationship between the final output voltage signal and the scan voltage is as follows:

[0103] U O =V R -V O1(3)

[0104] Among them, U O is the final voltage signal, V R is the scan voltage, V O1 It is the conversion voltage output by the fourth low voltage operational amplifier U4.

[0105] According to the relationship between the conversion voltage and the scanning voltage, the formula is:

[0106] V O1 =V R +i T R(4)

[0107] Among them, V R is the scanning voltage, i T is the weak current output by the detector, and R is the resistance of the fifth resistor R5.

[0108] According to formulas (3) and (4), the weak current output by the detector can be obtained as:

[0109]

[0110] In this embodiment, a floating power supply circuit is constructed that is linked to the satellite potential in real time. The scanning voltage is input to the floating power supply circuit to generate a voltage V R A symmetrical power supply rail is formed with the scan voltage as the center to avoid the load change affecting the scanning voltage accuracy and drive the large-capacity voltage-stabilizing diode network through the low output impedance of the operational amplifier; the scanning voltage is input to the voltage follower circuit, and the output power supply voltage provides a low-impedance power supply for the low-voltage operational amplifier of the subsequent transimpedance amplifier to avoid power supply rail fluctuations caused by sudden changes in load current; the supply voltage, scanning voltage and weak current signal output by the detector are input to the signal acquisition circuit, and pass through the current-voltage conversion circuit and subtraction circuit in sequence to achieve current-to-voltage conversion and high-frequency noise suppression, and output the final voltage signal.

[0111] To verify the performance advantages of the floating power supply microcurrent acquisition device used in this implementation, a complete circuit model was built using the Multisim 14.1 simulation platform, and a physical test system was constructed for dual-dimensional verification. The experiment focused on two key indicators: floating power supply rail stability and dynamic scanning voltage tracking accuracy. The following is a detailed experimental verification process and results analysis.

[0112] Use a function generator to input a triangular wave sweep voltage with a frequency of 1Hz and an amplitude of 30V to U1. Use the sweep voltage as the reference ground and use an oscilloscope to detect the floating power rail generated by the voltage regulator clamp. Use a DC voltage probe to detect the output voltage signal after processing the current signal input by the current source. The circuit connection is as follows: Figure 3 shown.

[0113] The simulation results show that within the full range of the scan voltage, V + With V R The difference is stable at +14.94V±0.04V, V - With V R The difference is maintained at -14.93V±0.03V (theoretical value±15V), and the relative deviation is less than 0.2%. Figure 4 As shown. The maximum relative error between the absolute value of the output voltage signal obtained by the current signal through the current-voltage conversion circuit and the subtraction circuit and the theoretical value (200mV) is 0.5%, and the circuit works normally. Figure 3 As shown. This is in line with design expectations.

[0114] To fully evaluate the actual performance of the floating power supply system, a test circuit was built based on simulation optimization parameters. The core of the system uses a high-voltage operational amplifier LTC6090 to build a voltage follower. The voltage regulator uses a 1N4744A with a voltage regulation value of 15V. A Keysight B2912B high-precision programmable power supply is used to simulate the sweep voltage V R The floating power supply output is connected to a current-to-voltage conversion circuit built with an operational amplifier OPA2196, and the voltage signal is measured using a Tektronix MSO44 mixed-signal oscilloscope.

[0115] Set V R A triangle wave sweep is performed at a frequency of 1 Hz and an amplitude of 30 V. The positive and negative floating power rails are observed in real time with an oscilloscope relative to V R The measured data shows that V + -V R =15.05V±0.08V, V - -V R =-14.92V±0.11V, the relative theoretical value deviation is less than 0.6%, such as Figure 4 As expected.

[0116] Example 2

[0117] like Figure 2 As shown, this embodiment provides a floating power supply micro-current acquisition method for space plasma detection, including:

[0118] Inputting the acquired scanning voltage into a floating power supply circuit to output a stable first power supply voltage and a second power supply voltage;

[0119] Inputting the first power supply voltage and the second power supply voltage into the voltage follower circuit, outputting the first follower power supply voltage and the second follower power supply voltage, and supplying power to the signal acquisition circuit;

[0120] The signal acquisition circuit receives the scanning voltage and the weak current signal output by the detector, and converts the weak current output by the detector into a voltage signal through the current-voltage conversion circuit and the subtraction circuit and suppresses high-frequency noise.

[0121] In this embodiment, (1) the acquired scan voltage is input to the floating power supply circuit, which outputs a stable first power supply voltage and a second power supply voltage.

[0122] Specifically, the circuit of the DA module generates a scan voltage V R , through the first high voltage operational amplifier U1, V R The output is directly sent to the middle node of the 15V voltage regulator (D1-D2), isolating the front-stage scanning voltage generation circuit from the rear-stage voltage regulator network to prevent load changes from affecting the scanning voltage accuracy; the large-capacity voltage regulator network is driven by the low output impedance of the first high-voltage operational amplifier U1; when the scanning voltage V R When the voltage fluctuates within the range of ±30V, the voltage drop is maintained at ±15V by the voltage stabilizing diode, generating a voltage drop of V R The voltage is proportionally distributed through the first resistor R1, the second resistor R2, the third resistor R3, and the fourth resistor R4, and the voltage regulator diode maintains a stable voltage drop of ±15V.

[0123] like Figure 1 As shown, when the scanning voltage V R When the voltage fluctuates within the range of ±30V, the first resistor R1 and the second resistor R2 are connected to the DC positive power supply +70V, the third resistor R3 and the fourth resistor R4 are connected to the DC negative power supply -70V, and the two voltage regulators are connected in parallel and connected in series with the two resistors. Since the voltage regulators are fixed at 15V and the voltage input of the middle node of the two parallel voltage regulators is V R The range is -30~30V, so the range of the resistor voltage division in the two parallel branches of the voltage regulator tube is 25~85V. The minimum voltage division value of the first resistor R1 and the second resistor R2 is 70-30-15, and the minimum voltage division value of the third resistor R3 and the fourth resistor R4 is -30-(-70)-15; the maximum voltage division value of the first resistor R1 and the second resistor R2 is 70-(-30)-15, and the maximum voltage division value of the third resistor R3 and the fourth resistor R4 is 30-(-70)-15; the resistance values ​​of the four resistors are equal and the voltage is evenly divided.

[0124] (2) Inputting the first power supply voltage and the second power supply voltage into the voltage follower circuit, outputting the first follower power supply voltage and the second follower power supply voltage, and supplying power to the signal acquisition circuit.

[0125] Specifically, the scan voltage V RThe input is sent to the voltage follower circuit, and a stable power supply voltage is obtained through two high-voltage operational amplifiers U2 and U3, providing a low-impedance power supply for the low-voltage operational amplifier U4 of the subsequent transimpedance amplifier, avoiding power supply rail fluctuations caused by sudden changes in load current.

[0126] (3) The signal acquisition circuit receives the scanning voltage and the weak current signal output by the detector, and converts the weak current output by the detector into a voltage signal through the current-voltage conversion circuit and the subtraction circuit and suppresses high-frequency noise.

[0127] Specifically, the received first follower power supply voltage and the second follower power supply voltage are used to power the fourth low-voltage operational amplifier in the signal acquisition circuit, thereby providing a stable low-impedance power supply for the fourth low-voltage operational amplifier U4.

[0128] The scanning voltage and the weak current signal output by the detector are input into the signal acquisition circuit. After passing through the current-voltage conversion circuit, the weak current signal output by the detector is converted into a voltage signal. The voltage signal passes through the subtraction circuit and uses the differential amplification principle to output the compensated voltage, that is, the final voltage signal. Mathematical operations are used to eliminate the coupling interference of the scanning bias voltage on the micro-current signal.

[0129] (4) Based on the relationship between the converted voltage signal and the scanning voltage, the weak current output by the detector is calculated.

[0130] According to formulas (3) and (4), the weak current output by the detector can be obtained as:

[0131]

[0132] The method of this embodiment is based on the floating power supply micro-current acquisition device in Example 1 to realize the detection of the weak current output by the detector.

[0133] Those skilled in the art will appreciate that the modules or steps of the present invention described above can be implemented using a general-purpose computer device. Alternatively, they can be implemented using program code executable by a computing device, which can then be stored in a storage device and executed by the computing device. Alternatively, they can be fabricated into separate integrated circuit modules, or multiple modules or steps can be fabricated into a single integrated circuit module for implementation. The present invention is not limited to any specific combination of hardware and software.

[0134] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A floating power supply micro-current acquisition device for space plasma detection, characterized in that: include: A floating power supply circuit, a voltage follower circuit, and a signal acquisition circuit are connected in sequence; The input end of the floating power supply circuit is connected to the circuit for generating the scanning voltage, and the scanning voltage is sequentially passed through the first high-voltage operational amplifier and the voltage divider module connected in series to output the first supply voltage and the second supply voltage, which are then input to the voltage follower circuit; The voltage follower circuit includes a second high-voltage operational amplifier and a third high-voltage operational amplifier connected in parallel, which are respectively connected to the first power supply voltage and the second power supply voltage to obtain a first follower power supply voltage and a second follower power supply voltage, and transmit them to the signal acquisition circuit; The signal acquisition circuit includes a current-voltage conversion circuit and a subtraction operation circuit connected in series. The input end is connected to the first follower power supply voltage and the second follower power supply voltage to provide power and voltage protection for the current-voltage conversion circuit. At the same time, the scanning voltage and the weak current signal output by the detector are input into the series current-voltage conversion circuit and the subtraction operation current in sequence to output the final voltage signal.

2. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The non-inverting input terminal of the first high-voltage operational amplifier is connected to a circuit for generating a scanning voltage, and the inverting input terminal is connected to an output terminal.

3. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The voltage divider module includes a resistor voltage divider network and a bipolar voltage stabilizing diode array; The resistor voltage divider network includes a first resistor voltage divider network and a second resistor voltage divider network; The bipolar zener diode array includes a first zener diode and a second zener diode; The first resistor divider network and the first voltage stabilizing diode are connected in series, and then connected in parallel with the second resistor divider network and the second voltage stabilizing diode in series; the input end of the parallel connection is connected to the output end of the first high-voltage operational amplifier.

4. The floating power supply micro-current acquisition device for space plasma detection according to claim 3, characterized in that: The first resistor divider network includes a first resistor and a second resistor; The second resistor divider network includes a third resistor and a fourth resistor; One end of the first resistor is connected in series with the second resistor, and the other end is connected to the positive terminal of the DC voltage, and the second resistor is connected in series with the negative terminal of the first voltage stabilizing diode; One end of the third resistor is connected in series with the fourth resistor, and the other end is connected to the negative terminal of the DC voltage. The third resistor is connected in series with the positive terminal of the second voltage stabilizing diode.

5. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The non-inverting input terminal of the second high-voltage operational amplifier is connected to the negative terminal of the first voltage-stabilizing diode; the second high-voltage operational amplifier is connected to the first high-voltage operational amplifier through the power supply terminal; the output terminal of the second high-voltage operational amplifier outputs the first follower power supply voltage.

6. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The non-inverting input terminal of the third high-voltage operational amplifier is connected to the positive terminal of the second voltage-stabilizing diode; the third high-voltage operational amplifier is connected to the first high-voltage operational amplifier through the power supply terminal; the output terminal of the third high-voltage operational amplifier outputs a second follower power supply voltage.

7. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The current-voltage conversion circuit includes a fourth low-voltage operational amplifier and a first-order low-pass filter network; The scanning voltage is input to the non-inverting input terminal of the fourth low-voltage operational amplifier; the inverting input terminal of the fourth low-voltage operational amplifier is connected to the detector; The two power supply terminals of the fourth low-voltage operational amplifier are respectively connected to the output terminal of the second high-voltage operational amplifier and the output terminal of the third high-voltage operational amplifier; The first first-order low-pass filter network includes a fifth resistor and a first capacitor connected in parallel, and two ends of the first first-order low-pass filter network are respectively connected to the inverting input terminal and the output terminal of the fourth low-voltage operational amplifier.

8. The floating power supply micro-current acquisition device for space plasma detection according to claim 1, characterized in that: The subtraction circuit includes a fifth high-voltage operational amplifier and a second first-order low-pass filter network; The non-inverting input terminal of the fifth high-voltage operational amplifier is connected to the non-inverting input terminal of the fourth low-voltage operational amplifier through a sixth resistor; the inverting input terminal of the fifth high-voltage operational amplifier is connected to the output terminal of the fourth low-voltage operational amplifier through a seventh resistor; The fifth high-voltage operational amplifier is connected to the first high-voltage operational amplifier, the second high-voltage operational amplifier and the third high-voltage operational amplifier through a power supply terminal; The non-inverting input terminal of the fifth high-voltage operational amplifier is connected in series with the eighth resistor and grounded; The second first-order low-pass filter network includes a ninth resistor and a second capacitor connected in parallel, and two ends of the second first-order low-pass filter network are respectively connected to the inverting input terminal and the output terminal of the fifth high-voltage operational amplifier.

9. A floating power supply microcurrent acquisition method for space plasma detection, characterized in that: include: Inputting the acquired scanning voltage into a floating power supply circuit to output a stable first power supply voltage and a second power supply voltage; Inputting the first power supply voltage and the second power supply voltage into the voltage follower circuit, outputting the first follower power supply voltage and the second follower power supply voltage, and supplying power to the signal acquisition circuit; The signal acquisition circuit receives the scanning voltage and the weak current signal output by the detector, and converts the weak current output by the detector into a voltage signal through the current-voltage conversion circuit and the subtraction circuit, thereby suppressing high-frequency noise. According to the relationship between the converted voltage signal and the scanning voltage, the weak current output by the detector is calculated.

10. The floating power supply micro-current collection method for space plasma detection according to claim 9, characterized in that: The weak current output by the detector is calculated as follows: Among them, i T is the weak current output by the detector, U O is the final voltage signal, and R is the resistance of the fifth resistor R5.

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