Tunnel hole induced polarization device

Abstract

The tunnel hole induced polarization device comprises a plurality of electrodes divided into a plurality of electrode arrays; a power supply control module provides different currents to the plurality of electrode arrays; a voltage sampling module collects potential differences generated by the tunnel hole induced polarization of the plurality of electrode arrays; a collection module collects the potential differences and converts and transmits the potential differences to an upper computer and converts and transmits instructions of the upper computer to a driving control module; the driving control module drives the power supply control module and the voltage sampling module respectively, the power supply control module comprises a power supply bus and a power supply relay array; an electromagnetic shielding module is arranged on the power supply relay array and is used for suppressing transient electromagnetic interference of a coil and electromagnetic interference of a switch contact.

Description

Technical Field

[0001] This invention relates to the field of geophysical exploration technology, specifically to a tunnel borehole polarization device. Background Technology

[0002] Induced polarization (IP) is an electrical exploration method that uses the differences in induced polarization effects among different rocks and ores as its material basis to explore underground geological conditions by observing and studying induced polarization anomalies. After years of development, tunnel IPV methods, especially multi-pore combined IPV tomography, have become an effective method for identifying hazardous water bodies. Its resistivity, polarizability, and other parameters are sensitive to the water content of the formation, and multi-pore combined IPV tomography can be used to invert and image the water body in front of the tunnel.

[0003] Due to the complex load environment of the excitation polarization device, the surrounding rock of the tunnel is an inductive load. Inductive loads are more likely to generate gas spark discharge and metal arc discharge than purely resistive loads, thus generating electromagnetic interference that affects the normal operation of the circuit.

[0004] Existing excitation polarization devices use acquisition cards with a large number of I / O ports, resulting in low I / O port utilization and poor circuit integration.

[0005] Existing excitation polarization devices cannot quickly cut off power during excitation polarization detection. Voltage fluctuations occur in the current loop due to the instantaneous power failure of the high voltage, resulting in poor control accuracy. Summary of the Invention

[0006] To address one or more of the problems existing in the prior art, the present invention provides a tunnel hole excitation polarization device, comprising a data acquisition module, a drive control module, a power supply control module, multiple electrodes, a voltage sampling module, and an electromagnetic shielding module. The multiple electrodes are divided into multiple electrode arrays. The power supply control module is configured to provide different currents to the multiple electrode arrays. The voltage sampling module is configured to acquire the potential difference generated by the multiple electrode arrays during tunnel hole excitation polarization. The data acquisition module is used to acquire the potential difference from the voltage sampling module, convert and transmit it to a host computer, and to convert and transmit instructions from the host computer to the drive control module. The drive control module is configured to drive the power supply control module and the voltage sampling module respectively. The power supply control module includes a power supply bus and a power supply relay array, through which the electrodes are connected to the power supply bus. The voltage sampling module includes a measurement relay array, a sampling bus, and multiple sampling channels, through which the electrodes are connected to the sampling bus and to the data acquisition module via the sampling channels. The electromagnetic shielding module is disposed within the power supply relay array and is used to suppress transient electromagnetic interference from the coil and electromagnetic interference from the switch contacts.

[0007] In some embodiments of the present invention, the power supply relay array includes multiple power supply relays, the electromagnetic shielding module includes a first switching transistor connected in parallel with the power supply relay coil and an RC network disposed at the power supply contact of the power supply relay, the RC network includes a first resistor and a first capacitor, the first resistor and the first capacitor are connected in series and then connected across the two ends of the power supply contact, and the first switching transistor is a diode;

[0008] Preferably, a second switching transistor is connected in parallel with the first resistor to form an RCD network, and the second switching transistor is a diode.

[0009] In some embodiments of the present invention, the voltage sampling module further includes a voltage divider follower unit and an impedance matching unit. The voltage divider follower unit includes a second resistor, a third resistor, a second capacitor, a third switch, and a first amplifier. The second and third resistors are voltage divider resistors, and the second capacitor is a sampling filter capacitor. The impedance matching unit includes a fourth resistor and a third capacitor. The fourth resistor is an impedance matching resistor, and the third capacitor is a filter capacitor.

[0010] One end of the second resistor is connected to the electrode, and the other end of the second resistor is connected to the positive input terminal of the first amplifier. The third resistor, the second capacitor, and the third switch are connected in parallel to the positive input terminal of the first amplifier. The inverting input terminal and the output terminal of the first amplifier are connected in parallel. One end of the fourth resistor is connected to the output terminal of the first amplifier, and the other end of the fourth resistor is connected to the acquisition module. One end of the third capacitor is connected to the other end of the fourth resistor, and the other end of the third capacitor is grounded.

[0011] Preferably, the third switching transistor is a bidirectional transient suppression diode;

[0012] Preferably, the resistance value of the fourth resistor is in the range of 0 to 20 ohms.

[0013] Preferably, the voltage divider follower unit and the impedance matching unit each further include at least one power supply filter capacitor. The power supply filter capacitor of the voltage divider follower unit is connected between the positive voltage drive terminal of the first amplifier and ground, and the power supply filter capacitor of the impedance matching unit is connected between the negative voltage drive terminal of the first amplifier and ground.

[0014] In some embodiments of the present invention, a constant current control module is further included, which is used to receive the control signal from the acquisition module and output a constant current signal to the power supply control module.

[0015] In some embodiments of the present invention, the constant current control module includes an isolation follower unit, a microcontroller, a second amplifier, a current feedback resistor, a fourth switch, and an adjustable AC / DC voltage output unit. The module acquires the analog voltage signal output as a control signal and sends it to the isolation follower unit for isolation and amplification. The signal then enters the microcontroller for ADC analog-to-digital conversion and is further converted to analog-to-digital signal by the microprocessor's internal DAC, outputting the voltage signal to the non-inverting input of the second amplifier. The inverting input of the second amplifier is connected to the current feedback resistor, and the output of the second amplifier is connected to the fourth switch. When the voltage at the non-inverting input of the second amplifier is higher than the voltage at the inverting input, the output of the second amplifier... When a high level is output, the fourth switch is turned on, and the microcontroller outputs a voltage signal to the adjustable AC / DC voltage output unit. The adjustable AC / DC voltage output unit adjusts the output drive voltage according to the voltage signal. The adjustable AC / DC voltage output unit is connected to the fourth switch to form a current loop. As the fourth switch is turned on, the voltage at the inverting input terminal of the second amplifier gradually approaches the voltage at the non-inverting input terminal, the output voltage of the second amplifier gradually decreases, and the voltage drop of the fourth switch gradually increases. The voltage on the current feedback resistor reaches the inverting input terminal through the feedback loop, and the voltage at the non-inverting input terminal will be higher than the voltage at the inverting input terminal. Dynamic balance is achieved in the negative feedback loop formed by the fourth switch and the second amplifier.

[0016] Preferably, the fourth switch is an N-channel MOSFET;

[0017] Preferably, the constant current control module further includes a voltage feedback unit, which is used to acquire the drain voltage of the fourth switching transistor and feed it back to the microprocessor.

[0018] In some embodiments of the present invention, the constant current control module further includes a sampling and adjustment unit, which collects the voltage value across the current feedback resistor and transmits it to the microcontroller. The microcontroller adjusts the output voltage of the adjustable AC / DC voltage output unit based on the voltage value collected by the sampling and adjustment unit.

[0019] In some embodiments of the present invention, the sampling adjustment unit includes a third amplifier, a fifth resistor and a sixth resistor. One end of the fifth resistor is connected to a current feedback resistor, and the other end of the fifth resistor is connected to the non-inverting input terminal of the third amplifier. The inverting input terminal and the output terminal of the third amplifier are connected to each other. One end of the sixth resistor is connected to the output terminal of the third amplifier, and the other end of the sixth resistor is connected to a microcontroller.

[0020] Preferably, the sampling adjustment unit further includes multiple power supply filter capacitors;

[0021] Preferably, the sampling adjustment unit further includes a rectifier diode, which is connected between the other end of the sixth resistor and ground;

[0022] Preferably, the sampling adjustment unit further includes a Zener diode connected to the non-inverting input terminal of the third amplifier.

[0023] In some embodiments of the present invention, the constant current control module further includes a current limiting protection unit, which is used to limit the output current.

[0024] In some embodiments of the present invention, the current limiting protection unit includes a seventh resistor, a fourth amplifier, an eighth resistor, and an optocoupler. One end of the seventh resistor is connected to a current feedback resistor, and the other end of the seventh resistor is connected to the inverting input terminal of the fourth amplifier. The non-inverting input terminal of the fourth amplifier is connected to a current limiting voltage. One end of the eighth resistor is connected to the input terminal of the fourth amplifier, and the other end of the eighth resistor is connected to the optocoupler. When the voltage on the current feedback resistor exceeds the current limiting voltage, the optocoupler is turned on, so that the output voltage of the adjustable AC / DC voltage output unit is 0.

[0025] In some embodiments of the present invention, the power supply bus of the power supply control module includes a dual-channel A-electrode bus, a single-channel A-electrode bus, a dual-channel B-electrode bus, and a single-channel B-electrode bus, and multiple electrode arrays are respectively connected to the dual-channel A-electrode bus, the single-channel A-electrode bus, the dual-channel B-electrode bus, and the single-channel B-electrode bus through multiple power supply relay arrays;

[0026] Preferably, the power supply control module further includes a single / dual-channel control relay, which is used to control whether the dual-channel A electrode bus and the dual-channel B electrode bus are connected or whether a single-channel A electrode bus and a single-channel B electrode bus are connected.

[0027] Preferably, the power supply control module further includes a direction relay, which is used to control the conduction direction of the dual-channel A-electrode bus and the dual-channel B-electrode bus, as well as the conduction direction of the single-channel A-electrode bus and the single-channel B-electrode bus.

[0028] Preferably, the power supply control module further includes a grounding resistance relay, which is used for measuring grounding resistance;

[0029] Preferably, the power supply control module further includes a fifth switch, a sixth switch, and a ninth resistor. One end of the fifth switch is connected to the constant current control module, and the other end of the fifth switch is connected to the direction relay. One end of the sixth switch is connected to the constant current control module through the ninth resistor. The acquisition module acquires the voltage across the ninth resistor to obtain the current signal. More preferably, the fifth switch and the sixth switch are MOS-FETs.

[0030] In some embodiments of the present invention, a power conversion module is also included, which is used to supply power to other modules. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0032] Figure 1 This is a schematic block diagram of one embodiment of the tunnel hole excitation polarization device described in this invention;

[0033] Figure 2 This is a schematic diagram of the circuit principle of one embodiment of the electromagnetic shielding module described in this invention;

[0034] Figure 3 This is a schematic diagram of an embodiment of the voltage sampling module described in this invention;

[0035] Figure 4 This is a schematic diagram of the circuit principle of an embodiment of the voltage divider follower unit and impedance matching unit described in this invention;

[0036] Figure 5 This is a schematic diagram of an embodiment of the connection between the power supply control module, the constant current control module, and the acquisition module described in this invention;

[0037] Figure 6 This is a schematic diagram of the configuration block of an embodiment of the constant current control module described in this invention;

[0038] Figure 7 This is a schematic diagram of the circuit principle of one embodiment of the sampling adjustment unit and current limiting protection unit described in this invention;

[0039] Figure 8 This is a schematic diagram of the circuit principle of one embodiment of the power conversion module of the present invention;

[0040] The system includes: a host computer 1; a power conversion module 10; a data acquisition module 20; a constant current control module 30; an isolation follower unit 31; a microcontroller 32; a second amplifier U2; a fourth switch D4; a current feedback resistor 33; a voltage feedback unit 34; a sampling and adjustment unit 35; a third amplifier U3; a fifth resistor R5; a sixth resistor R6; a rectifier diode D7; a Zener diode D8; a current limiting protection unit 36; a seventh resistor R7; a fourth amplifier U4; an eighth resistor R8; an optocoupler U6; an adjustable AC / DC voltage output unit 37; a drive control module 40; a power supply control module 50; and a power supply relay J1. -J128, Relay switch S1, Grounding resistor relay JD, Fifth switch D5, Sixth switch D6, Ninth resistor R9, Direction relay JF, Single / dual-channel control relay JW; Electromagnetic shielding module 60, First switch D1, First resistor R1, First capacitor C1, Second switch D2; Electrodes E1-E128; Voltage sampling module 70, Measurement relay array 71, Sampling bus, Sampling channel, Second resistor R2, Third resistor R3, Second capacitor C2, Third switch C3, First amplifier U1, Fourth resistor R4, Third capacitor C3, Power supply filter capacitor C. Detailed Implementation

[0041] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0042] The following disclosure provides many different implementations or examples for carrying out different structures of the present invention. Of course, these are merely examples and are not intended to limit the invention. Preferred embodiments of the invention are described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the invention.

[0043] Figure 1 This is a schematic block diagram of one embodiment of the tunnel borehole excitation polarization device described in this invention, as shown below. Figure 1As shown, the tunnel borehole polarization device includes a data acquisition module 20, a drive control module 40, a power supply control module 50, an electromagnetic shielding module 60, multiple electrodes, and a voltage sampling module 70. The multiple electrodes are divided into multiple electrode arrays. The power supply control module 50 is configured to provide different currents to the multiple electrode arrays. The voltage sampling module 70 is configured to acquire the potential difference generated by the multiple electrode arrays during tunnel borehole polarization. The data acquisition module 20 is used to acquire the potential difference from the voltage sampling module 70, convert it to transmit to the host computer 1, and convert and transmit the instructions from the host computer 1 to the drive control module 40. The drive control module 40 is configured to drive the power supply control module 50 and the voltage sampling module 70 respectively. The power supply control module 50 includes a power supply bus and a power supply relay array, through which the electrodes are connected to the power supply bus. The electromagnetic shielding module 60 is disposed in the power supply relay array and is used to suppress transient electromagnetic interference of the coil and electromagnetic interference of the switch contacts.

[0044] In some embodiments of the present invention, the tunnel hole excitation polarization device further includes a constant current control module 30, which is used to receive the control signal from the acquisition module 20 and output a constant current signal to the power supply control module 50.

[0045] During the polarization detection process, the host computer 1 sends a control command to the acquisition module 20. The acquisition module 20 outputs a voltage analog signal to the constant current control module 30. The constant current control module 30 outputs a corresponding constant current signal based on the voltage analog signal. Simultaneously, the acquisition module 20 outputs a digital signal to the drive control module 40 to control the switching of the power supply relay in the power supply control module 50, enabling the conduction of any two power supply electrodes (electrodes connected to the power supply relay) among multiple electrodes. The constant current output signal is then transmitted to the conducting electrodes (the electrodes are pre-laid in the tunnel hole via cables) to provide constant current power for polarization detection. At the same time, the acquisition module 20 outputs a digital signal to the drive control module 40 to control the switching of the measurement relay in the voltage sampling module 70, enabling the conduction of multiple measurement electrodes (electrodes connected to the measurement relay). The acquisition module 20 acquires one constant current output signal from the electrode circuit and multiple voltage signals from the voltage sampling module 70, and transmits them to the host computer 1 for full waveform data acquisition. Afterward, the power supply electrode and measurement electrode are switched, and the above process is repeated to continuously track electrodes and acquire data, ultimately completing the polarization detection process. The data collected by the host computer will be processed to obtain resistivity inversion imaging results and polarizability inversion imaging results in the three-dimensional inversion area in front of the tunnel, providing geophysical exploration basis for the final geological interpretation.

[0046] In some embodiments of the present invention, the tunnel hole excitation polarization device further includes a power conversion module 10, which is used to supply power to other modules.

[0047] The surrounding rock of the tunnel is considered an inductive load. Inductive loads are prone to gas spark discharge and metallic arc discharge, which generate electromagnetic interference and affect the normal operation of the circuit. This invention suppresses electromagnetic interference from two aspects: the suppression of transient electromagnetic interference of the relay coil and the suppression of electromagnetic interference of the switch contacts. Figure 2 As shown, the electromagnetic shielding module 60 includes a first switching transistor D1 connected in parallel with the power supply relay coil and an RC network disposed at the power supply contact of the power supply relay. The RC network includes a first resistor R1 and a first capacitor C1. The first resistor R1 and the first capacitor C1 are connected in series across the two ends of the power supply contact. The first switching transistor D1 is a diode.

[0048] Preferably, a second switch D2 is connected in parallel with the first resistor R1 to form an RCD network, and the second switch D2 is a diode.

[0049] like Figure 2 As shown, the power supply relay array includes multiple power supply relays (e.g., power supply relays J1-J128). The coil of each power supply relay is connected in parallel with a first switching transistor D1, which provides a release circuit for the induced electromotive force generated by the transient of the coil and suppresses interference in the power supply relay coil. In this way, the energy loss is small and the transient voltage is low. The left and right sets of contacts of the power supply relays have electromagnetic interference shielding circuits. Taking the electromagnetic interference shielding circuit on the left side of the power supply relay as an example, in the figure, the excitation source (from the constant current signal output by the constant current control module 30) outputs an excitation signal, which is transmitted to the inductive load (the inductive load is the load in the power supply electrode circuit, and the surrounding rock of the tunnel is considered as the inductive load) through the power supply contacts 5 and 6 of the power supply relay. The first resistor R1 and the first capacitor C1 are connected in series across the two ends of the power supply contacts 5 and 6. When the relay switch S1 is opened, the energy stored in the inductive load is discharged through the RC network, avoiding electromagnetic interference generated by the discharge between the contacts. A second switching transistor D2 is connected in parallel with the first resistor R1. When the relay switch S1 is open, the energy in the inductive load is released through the circuit composed of R, C, and D. Since the second switching transistor D2 is forward-biased and has very low internal resistance, the energy can be released quickly.

[0050] Figure 3 This is a schematic diagram of one embodiment of the voltage sampling module described in this invention, as shown below. Figure 3 As shown, the voltage sampling module 70 includes a measurement relay array 71, a sampling bus (e.g., M bus and N bus) and multiple sampling channels (e.g., M sampling channel and N sampling channel). The electrodes are connected to the sampling bus through the measurement relay array 71 and connected to the acquisition module 20 through the sampling channels, and then enter the acquisition module 20 for data acquisition and processing.

[0051] In some embodiments of the present invention, such as Figure 4As shown, the voltage sampling module 70 further includes a voltage divider follower unit and an impedance matching unit. The voltage divider follower unit includes a second resistor R2, a third resistor R3, a second capacitor C2, a third switch C3, and a first amplifier U1. The second resistor R2 and the third resistor R3 are voltage divider resistors, and the second capacitor C2 is a sampling filter capacitor. The impedance matching unit includes a fourth resistor R4 and a third capacitor C3. The fourth resistor R4 is an impedance matching resistor, and the third capacitor C3 is a filter capacitor.

[0052] One end of the second resistor R2 is connected to the electrode, and the other end of the second resistor R2 is connected to the positive input terminal of the first amplifier U1. The third resistor R3, the second capacitor C2, and the third switch C3 are connected in parallel to the positive input terminal of the first amplifier U1. The inverting input terminal and the output terminal of the first amplifier U1 are connected in parallel. One end of the fourth resistor R4 is connected to the output terminal of the first amplifier U1, and the other end of the fourth resistor R4 is connected to the acquisition module 20. One end of the third capacitor C3 is connected to the other end of the fourth resistor R4, and the other end of the third capacitor C3 is grounded.

[0053] Preferably, the third switch C3 is a bidirectional transient suppression diode.

[0054] Preferably, the resistance value of the fourth resistor R4 is in the range of 0 to 20 ohms.

[0055] Preferably, the voltage divider follower unit and the impedance matching unit each further include at least one power supply filter capacitor C. The power supply filter capacitor C of the voltage divider follower unit is connected between the positive voltage drive terminal of the first amplifier U1 and ground, and the power supply filter capacitor C of the impedance matching unit is connected between the negative voltage drive terminal of the first amplifier U1 and ground.

[0056] In some embodiments of the present invention, the tunnel hole excitation polarization device includes 128 electrodes, namely electrodes E1-E128, which are divided into four groups of motor arrays, namely electrode arrays E1-E32, electrode arrays E33-E64, electrode arrays E65-E96 and electrode arrays E97-E128. All four groups of electrode arrays can be used as M or N electrodes (both M and N electrodes are positive, and an additional reference electrode is connected as the negative electrode). The sampling channel is divided into M sampling channel and N sampling channel. The four groups of electrode arrays are connected to the M bus or N bus through the measurement relay, and enter the subsequent sampling channel. After passing through the voltage divider follower and sampling matching circuit, the data enters the acquisition module 20 for data acquisition and processing, realizing a maximum of 64 channels of voltage parallel acquisition.

[0057] The voltage sampling module 70 of this invention is adapted to the detection requirements of borehole and tunneling instruments, meaning that all four sets of electrodes can be used as either M or N electrodes for voltage acquisition; the M sampling channel and the N sampling channel each include 32 sampling channels. A total of 64 sampling channels are provided, each including a voltage divider follower circuit and an impedance matching circuit, such as... Figure 4 As shown, the sampling voltage Vin (both M and N electrodes are positive, and a reference electrode is connected to be considered negative; the Vin voltage is the voltage of the M or N electrode relative to the reference electrode) is first divided by voltage divider resistors R2 and R3, filtered by C2, and then enters the first amplifier U1. After passing through the operational amplifier follower circuit of the first amplifier U1, it enters the acquisition module 20 for analog signal acquisition through the RC filter circuit composed of R4 and C3. Because the input impedance of the acquisition module 20 is too high, resistor R4 needs to be selected with a relatively small resistance value (0-20 ohms) for impedance matching. D3 at the non-inverting input of U1 provides voltage regulation protection for the first amplifier U1.

[0058] Figure 5 This is a schematic diagram of an embodiment of the connection between the power supply control module, the constant current control module, and the acquisition module described in this invention, as shown below. Figure 5 As shown, the power supply control module 50 consists of a power supply bus and a power supply relay array. The power supply relay array connects the electrodes to the power supply electrode bus to realize the power supply function of the electrodes.

[0059] In some embodiments of the present invention, the tunnel borehole excitation polarization device further includes a constant current control module 30, which is used to receive the control signal from the acquisition module 20 and output a constant current signal to the power supply control module 50. The acquisition module 20 controls the constant current control module 30 to output a constant current signal.

[0060] In some embodiments of the present invention, the power supply bus of the power supply control module 50 includes a dual-channel A-electrode bus, a single-channel A-electrode bus, a dual-channel B-electrode bus, and a single-channel B-electrode bus. Multiple electrode arrays are respectively connected to the dual-channel A-electrode bus, the single-channel A-electrode bus, the dual-channel B-electrode bus, and the single-channel B-electrode bus through multiple power supply relay arrays.

[0061] In some embodiments of the present invention, the power supply control module 50 further includes a single / dual-channel control relay JW, which is used to control whether the dual-channel A electrode bus and the dual-channel B electrode bus are connected or whether a single-channel A electrode bus and a single-channel B electrode bus are connected.

[0062] In some embodiments of the present invention, the power supply control module 50 further includes a direction relay JF, which is used to control the conduction direction of the dual-channel A-electrode bus and the dual-channel B-electrode bus, as well as the conduction direction of the single-channel A-electrode bus and the single-channel B-electrode bus.

[0063] In some embodiments of the present invention, the power supply control module 50 further includes a grounding resistance relay JD, which is used to measure the grounding resistance. The grounding resistance is used to determine the electrode conduction quality, determine whether the electrode contact is good, and is used for subsequent electrode selection.

[0064] In some embodiments of the present invention, the power supply control module 50 further includes a fifth switch D5, a sixth switch D6, and a ninth resistor R9. One end of the fifth switch D5 is connected to the constant current control module 30, and the other end of the fifth switch D5 is connected to the directional relay JF. One end of the sixth switch D6 is connected to the constant current control module 30 through the ninth resistor R9. The acquisition module 20 acquires the voltage across the ninth resistor R9 to obtain the current signal. More preferably, the fifth switch D5 and the sixth switch D6 are MOS-FETs.

[0065] In some embodiments of the present invention, such as Figure 5 As shown, four electrode arrays, E1-E32, E33-E64, E65-E96, and E97-E128, are connected to a dual-channel A-electrode bus, a single-channel A-electrode bus, a dual-channel B-electrode bus, and a single-channel B-electrode bus, respectively, via multiple power supply relays. Odd-numbered electrodes are connected to a single-channel electrode bus, and even-numbered electrodes are connected to a dual-channel electrode bus. The single / dual-channel control relay JW controls whether a single or dual electrode is connected. The direction relay JF controls the forward and reverse directions of the current loop, enabling forward power supply from A to B or reverse power supply from B to A. The grounding resistance relay JD measures the grounding resistance.

[0066] During operation, the acquisition module 20 sends an analog control signal to the constant current control module 30, controlling the constant current control module 30 to output a constant current signal at its positive terminal. This constant current signal is controlled by the fifth switch D5 for on / off switching, the current direction is controlled by the direction relay JF, and the current loop is divided into four buses by the single / dual-channel control relay JW: dual-channel A-electrode bus, single-channel A-electrode bus, dual-channel B-electrode bus, and single-channel B-electrode bus. The power supply relays J1-J128 select between the A and B electrodes. The current passes through the sixth switch D6 and then through the ninth resistor R9 (sampling resistor) back to the negative terminal of the constant current control module 30. The acquisition module 20 obtains the current signal value by sampling the voltage across the ninth resistor, which is then used for subsequent data acquisition and processing.

[0067] During grounding resistance measurement, the constant current control module 30 outputs a constant current signal, which passes through the direction relay JF, the single / dual-channel control relay JW, and the power supply relay, controlling the fifth switching transistor and the sixth switching transistor D6 to conduct, thus ensuring the entire current loop is in a conducting state. The acquisition module 20 simultaneously acquires the voltage signal through the grounding resistance relay JD; this voltage signal represents the voltage across electrodes A and B. The acquisition module 20 obtains the current signal value by acquiring the voltage across the ninth resistor R9. According to Ohm's law, the grounding resistance value can be calculated using the voltage and current values ​​of electrodes A and B.

[0068] The fifth switch D5 and the sixth switch D6 can realize the rapid turn-off of the current loop, achieve the effect of rapid power-off in the excitation polarization detection, and eliminate the voltage fluctuation caused by the instantaneous high voltage power-off in the current loop.

[0069] like Figure 5 As shown, the dashed box contains two sets of contacts of a relay. The relay model used is the American Tyco IM03 relay, which can further improve the integration of the circuit and reduce the number of switching devices by nearly 50%.

[0070] In some embodiments of the present invention, the drive control module drives the measurement relay array and power supply relay array inside the voltage sampling module and power supply control module, respectively. It includes a serial-to-parallel conversion unit and a logic drive unit. The serial-to-parallel conversion unit consists of multiple 8-bit serial input, parallel output shift registers, which can convert the serial signal from the CNC acquisition module into a parallel signal for output, reducing the use of the acquisition module's I / O ports and improving I / O port utilization and circuit integration. The converted parallel signal is then sent to the logic drive unit, which consists of multiple decoder circuits. This circuit can accept 4-bit high-active binary address input and provides 16 mutually exclusive low-active outputs, further improving circuit integration.

[0071] In some embodiments of the present invention, the acquisition module uses a USB-6255 acquisition card from National Instruments.

[0072] Figure 6 This is a schematic diagram of the structural block diagram of an embodiment of the constant current control module described in this invention, as shown below. Figure 6As shown, the constant current control module 30 includes an isolation follower unit 31, a microcontroller 32, a second amplifier U2, a current feedback resistor 33, a fourth switch D4, and an adjustable AC / DC voltage output unit 37. The voltage analog signal output by the acquisition module 20 is used as a control signal to the isolation follower unit 31 for isolation and amplification. Then, it enters the microcontroller 32 for ADC analog-to-digital conversion, and after passing through the microprocessor's internal DAC digital-to-analog conversion, the voltage signal is output to the non-inverting input terminal of the second amplifier U2. The inverting input terminal of the second amplifier U2 is connected to the current feedback resistor 33, and the output terminal of the second amplifier U2 is connected to the fourth switch D4. When the voltage at the non-inverting input terminal of the second amplifier U2 is higher than the voltage at the inverting input terminal, the output terminal of the second amplifier U2 outputs... When a high level is output, the fourth switch D4 is turned on, and the microcontroller 32 outputs a voltage signal to the adjustable AC / DC voltage output unit 37. The adjustable AC / DC voltage output unit 37 adjusts the output drive voltage according to the voltage signal. The adjustable AC / DC voltage output unit 37 is connected to the fourth switch D4 to form a current loop. As the fourth switch D4 is turned on, the voltage at the inverting input terminal of the second amplifier U2 gradually approaches the voltage at the positive input terminal, the output voltage of the second amplifier U2 gradually decreases, and the voltage drop of the fourth switch D4 gradually increases. The voltage on the current feedback resistor 33 reaches the inverting input terminal through the feedback loop, and the voltage at the positive input terminal will be higher than the voltage at the inverting input terminal. Dynamic balance is achieved in the negative feedback loop formed by the fourth switch D4 and the second amplifier U2.

[0073] In some embodiments of the present invention, the fourth switch D4 is an N-channel MOS-FET, and the current feedback resistor 33 is connected to the source of the fourth switch D4 and the second amplifier U2.

[0074] In some embodiments of the present invention, the constant current control module 30 further includes a voltage feedback unit 34, which is used to acquire the drain voltage of the fourth switching transistor D4 and feed it back to the microprocessor.

[0075] Preferably, the voltage feedback unit 34 includes a pre-stage voltage divider resistor, a Zener diode, a fifth amplifier, and a post-stage voltage divider resistor. The pre-stage and post-stage voltage divider resistors adopt a common two-resistor voltage divider circuit in the prior art. The drain voltage Vd is divided by the pre-stage voltage divider resistor and enters the non-inverting input terminal of the fifth amplifier. Since the Vd voltage is higher than the input range of the fifth amplifier, it is regulated by the Zener diode at the non-inverting input terminal. The inverting input terminal of the fifth amplifier is directly connected to the output terminal. The output terminal is divided again by the post-stage voltage divider resistor and then enters the microprocessor for voltage acquisition.

[0076] The present invention can also adjust the voltage across the source and drain terminals of the MOS-FET to reduce the power consumption of the overall circuit and reduce the heat generation of the MOS-FET itself. The voltage feedback unit 34 collects the drain voltage Vd of the MOS-FET, which is processed by the microcontroller 32. The microcontroller 32 changes the voltage output signal to the adjustable AC / DC voltage output module, so that the output voltage of the adjustable AC / DC voltage output module can be continuously adjusted to control the Vd voltage within a certain safe range.

[0077] In some embodiments of the present invention, the constant current control module 30 further includes a sampling adjustment unit 35, which collects the voltage value on the current feedback resistor 33 and transmits it to the microcontroller 32. The microcontroller 32 adjusts the output voltage of the adjustable AC / DC voltage output unit 37 based on the voltage value collected by the sampling adjustment unit 35.

[0078] In some embodiments of the present invention, such as Figure 7 As shown, the sampling adjustment unit 35 includes a third amplifier U3, a fifth resistor R5 and a sixth resistor R6. One end of the fifth resistor R5 is connected to the current feedback resistor 33, and the other end of the fifth resistor R5 is connected to the non-inverting input terminal of the third amplifier U3. The inverting input terminal and the output terminal of the third amplifier U3 are connected to each other. One end of the sixth resistor R6 is connected to the output terminal of the third amplifier U3, and the other end of the sixth resistor R6 is connected to the microcontroller 32.

[0079] Preferably, the sampling adjustment unit 35 further includes multiple power supply filter capacitors C.

[0080] Preferably, the sampling adjustment unit 35 further includes a rectifier diode D7, which is connected between the other end of the sixth resistor R6 and ground.

[0081] Preferably, the sampling adjustment unit 35 further includes a Zener diode D8, which is connected to the non-inverting input terminal of the third amplifier U3.

[0082] In some embodiments of the present invention, the constant current control module 30 further includes a current limiting protection unit 36, which is used to limit the output current.

[0083] In some embodiments of the present invention, such as Figure 7As shown, the current limiting protection unit 36 ​​includes a seventh resistor R7, a fourth amplifier U4, an eighth resistor R8, and an optocoupler U6. One end of the seventh resistor R7 is connected to the current feedback resistor 33, and the other end of the seventh resistor R7 is connected to the inverting input terminal of the fourth amplifier U4. The non-inverting input terminal of the fourth amplifier U4 is connected to the current limiting voltage. One end of the eighth resistor R8 is connected to the input terminal of the fourth amplifier U4, and the other end of the eighth resistor R8 is connected to the optocoupler U6. When the voltage on the current feedback resistor 33 exceeds the current limiting voltage, the optocoupler U6 is turned on, making the output voltage of the adjustable AC / DC voltage output unit 37 0.

[0084] In some embodiments of the present invention, the constant current control module 30 receives control signals from the acquisition module 20 and outputs a constant current signal. Specifically, the acquisition module 20 outputs a voltage analog signal to the constant current control module 30, and the constant current control module 30 outputs a corresponding constant current based on the analog voltage signal. The current output range is 0–200 mA, and the voltage output range of the adjustable AC / DC voltage output unit 37 is 0–500 V. The positive terminal of the output voltage of the adjustable AC / DC voltage output unit 37 supplies power to electrode A of the control unit, and is output from electrode B in the power supply control module 50 to the N-channel MOS-FET, and then returns to the negative terminal of the adjustable AC / DC voltage output unit 37 via the current feedback resistor 33.

[0085] The acquisition module 20 outputs an analog voltage signal to the constant current control unit. First, the signal is isolated by the isolation follower unit 31, using an ISO124 isolation amplifier. Then, the signal enters the microcontroller 32 for ADC analog-to-digital conversion, and finally, through the microprocessor's internal DAC digital-to-analog conversion, the voltage signal is output to the non-inverting input of the second amplifier U2. The inverting input of the second amplifier U2 is connected to a current feedback resistor 33, and the output of the second amplifier U2 is connected to the fourth switching transistor (N-channel MOS-FET). The supply voltage of the second amplifier U2 is ±12V, with millivolt-level offset voltage to ensure accurate current control. Since the N-channel MOS-FET conducts when the gate voltage is higher than the source voltage, when the control signal is applied, according to the op-amp's input-output characteristic curve, the voltage at the non-inverting input is higher than the voltage at the inverting input, and the op-amp's output voltage is 12V, meaning the MOS-FET's gate voltage is 12V. At this time, because the current feedback resistor 33 is grounded, the MOS-FET's source voltage is 0V, satisfying the conduction condition, and the MOS-FET begins to conduct. Simultaneously, the microcontroller 32 outputs a voltage signal to the adjustable AC / DC voltage output unit 37. The adjustable AC / DC voltage output unit 37 adjusts the output drive voltage according to this voltage signal, forming a current loop under the drive of the adjustable AC / DC voltage output unit 37. As the MOS-FET turns on, the inverting voltage of the second amplifier U2 gradually approaches the non-inverting voltage. According to the input-output characteristic curve of the second amplifier U2, the output voltage of the second amplifier U2 gradually decreases, the voltage drop of the MOS-FET gradually increases, and the voltage across the feedback resistor reaches the inverting input terminal through the feedback loop. At this time, the non-inverting voltage will be higher than the inverting voltage again. In the negative feedback loop formed by the MOS-FET, the voltage feedback unit 34, and the microprocessor, the circuit eventually reaches dynamic equilibrium.

[0086] The sampling and adjustment unit 35 can calculate the real-time current value by collecting the voltage value on the current feedback resistor 33. The microcontroller 32 collects the voltage and, through an internal algorithm (which adjusts the constant current signal to achieve fast and stable output of the constant current signal), quickly adjusts the output voltage of the adjustable AC / DC voltage output module.

[0087] The adjustable AC / DC voltage output unit 37 converts 220V AC voltage into an adjustable 0-500V DC voltage, and outputs 0-500V DC voltage according to the 0-5V control voltage output by the microcontroller 32.

[0088] The current limiting protection unit 36 ​​is mainly used to limit the output current of the constant current control module 30 to prevent the output current from increasing instantaneously when the external power supply electrode and electrode B are short-circuited, since the output voltage remains unchanged. It provides current limiting protection for the instrument's output current circuit.

[0089] like Figure 7As shown, the output control voltage is the 0-5V control voltage of the adjustable AC / DC voltage output unit 37. The current sampling voltage is the voltage across the feedback resistor, which passes through the seventh resistor R7 and enters the inverting input of the fourth amplifier U4 (voltage comparator). The current sampling voltage is compared with the current limiting voltage. When the current sampling voltage exceeds the current limiting voltage at the non-inverting input, the fourth amplifier U4 outputs a -12V voltage. Current flows through the front stage of optocoupler U6, causing the LED of optocoupler U6 to light up, and the phototransistor in the subsequent stage to conduct. Since the diode voltage drop at the source and drain of the phototransistor is 0.7V, the output control voltage here is 0V. The output voltage drop of the AC / DC voltage output module is adjusted to 0V.

[0090] Figure 8 This is a circuit diagram illustrating one embodiment of the power conversion module 10 of the present invention, as shown below. Figure 8 As shown, the power conversion module 10 is used to supply power to other modules.

[0091] like Figure 8 As shown, the main function of the power conversion module is to convert the 220V AC voltage to the 12V DC voltage required by the internal modules of the instrument through the LHE60-20B12 switching power supply module, and to convert the 12V DC voltage to ±12V and 5V voltage through the URA2412LD-30WR3 module and the URB2405LD-30WR3 module to power other modules of the instrument.

[0092] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A tunnel borehole excitation polarization device, characterized in that, The system includes a data acquisition module, a drive control module, a power supply control module, multiple electrodes, a voltage sampling module, and an electromagnetic shielding module. The multiple electrodes are divided into multiple electrode arrays. The power supply control module is configured to provide different currents to the multiple electrode arrays. The voltage sampling module is configured to acquire the potential difference generated by the polarization of the multiple electrode arrays in the tunnel hole. The data acquisition module is used to acquire the potential difference from the voltage sampling module, convert and transmit it to the host computer, and convert and transmit instructions from the host computer to the drive control module. The drive control module is configured to drive both the power supply control module and the voltage sampling module. The power supply control module includes a power supply bus and a power supply relay array, through which the electrodes are connected to the power supply bus. The voltage sampling module includes a measurement relay array, a sampling bus, and multiple sampling channels, through which the electrodes are connected to the sampling bus and then to the data acquisition module via the sampling channels. The electromagnetic shielding module is located within the power supply relay array and is used to suppress transient electromagnetic interference from the coil and electromagnetic interference from the switch contacts. The power supply relay array includes multiple power supply relays. The electromagnetic shielding module includes a first switching transistor connected in parallel with the power supply relay coil and an RC network disposed at the power supply contact of the power supply relay. The RC network includes a first resistor and a first capacitor. The first resistor and the first capacitor are connected in series and then connected across the two ends of the power supply contact. The first switching transistor is a diode. It also includes a constant current control module, which is used to receive the control signal from the acquisition module and output a constant current signal to the power supply control module; The constant current control module includes an isolation follower unit, a microcontroller, a second amplifier, a current feedback resistor, a fourth switch, and an adjustable AC / DC voltage output unit. The module's output analog voltage signal is used as a control signal and sent to the isolation follower unit for isolation and amplification. The signal then enters the microcontroller for ADC (Analog-to-Digital Conversion), and after internal DAC (Digital-to-Analog Conversion), the voltage signal is output to the non-inverting input of the second amplifier. The inverting input of the second amplifier is connected to the current feedback resistor, and the output of the second amplifier is connected to the fourth switch. When the voltage at the non-inverting input of the second amplifier is higher than the voltage at the inverting input, the output of the second amplifier is high. When all four switches are turned on, the microcontroller outputs a voltage signal to the adjustable AC / DC voltage output unit. The adjustable AC / DC voltage output unit adjusts the output drive voltage according to this voltage signal. The adjustable AC / DC voltage output unit is connected to the fourth switch to form a current loop. As the fourth switch is turned on, the voltage at the inverting input terminal of the second amplifier gradually approaches the voltage at the non-inverting input terminal. The output voltage of the second amplifier gradually decreases, and the voltage drop across the fourth switch gradually increases. The voltage across the current feedback resistor reaches the inverting input terminal through the feedback loop. The voltage at the non-inverting input terminal will be higher than the voltage at the inverting input terminal. Dynamic balance is achieved in the negative feedback loop formed by the fourth switch and the second amplifier.

2. The tunnel borehole excitation polarization device according to claim 1, characterized in that, A second switching transistor is connected in parallel with the first resistor to form an RCD network, and the second switching transistor is a diode.

3. The tunnel borehole excitation polarization device according to claim 1, characterized in that, The voltage sampling module further includes a voltage divider follower unit and an impedance matching unit. The voltage divider follower unit includes a second resistor, a third resistor, a second capacitor, a third switching transistor, and a first amplifier. The second and third resistors are voltage divider resistors, and the second capacitor is a sampling filter capacitor. The impedance matching unit includes a fourth resistor and a third capacitor. The fourth resistor is an impedance matching resistor, and the third capacitor is a filter capacitor. One end of the second resistor is connected to the electrode, and the other end of the second resistor is connected to the positive input terminal of the first amplifier. The third resistor, the second capacitor, and the third switch are connected in parallel to the positive input terminal of the first amplifier. The inverting input terminal of the first amplifier is connected to the output terminal. One end of the fourth resistor is connected to the output terminal of the first amplifier, and the other end of the fourth resistor is connected to the acquisition module. One end of the third capacitor is connected to the other end of the fourth resistor, and the other end of the third capacitor is grounded.

4. The tunnel borehole excitation polarization device according to claim 3, characterized in that, The third switching transistor is a bidirectional transient suppression diode.

5. The tunnel borehole excitation polarization device according to claim 3, characterized in that, The resistance value of the fourth resistor is in the range of 0~20 ohms.

6. The tunnel borehole excitation polarization device according to claim 3, characterized in that, The voltage divider follower unit and the impedance matching unit each further include at least one power supply filter capacitor. The power supply filter capacitor of the voltage divider follower unit is connected between the positive voltage drive terminal of the first amplifier and ground, and the power supply filter capacitor of the impedance matching unit is connected between the negative voltage drive terminal of the first amplifier and ground.

7. The tunnel borehole excitation polarization device according to claim 1, characterized in that, The fourth switch is an N-channel MOS-FET.

8. The tunnel borehole excitation polarization device according to claim 1, characterized in that, The constant current control module also includes a voltage feedback unit, which is used to collect the drain voltage of the fourth switching transistor and feed it back to the microprocessor.

9. The tunnel borehole excitation polarization device according to claim 1, characterized in that, The constant current control module also includes a sampling and adjustment unit, which collects the voltage value across the current feedback resistor and transmits it to the microcontroller. The microcontroller adjusts the output voltage of the adjustable AC / DC voltage output unit based on the voltage value collected by the sampling and adjustment unit.

10. The tunnel borehole excitation polarization device according to claim 9, characterized in that, The sampling adjustment unit includes a third amplifier, a fifth resistor, and a sixth resistor. One end of the fifth resistor is connected to a current feedback resistor, and the other end of the fifth resistor is connected to the non-inverting input terminal of the third amplifier. The inverting input terminal and the output terminal of the third amplifier are connected to each other. One end of the sixth resistor is connected to the output terminal of the third amplifier, and the other end of the sixth resistor is connected to a microcontroller.

11. The tunnel borehole excitation polarization device according to claim 10, characterized in that, The sampling and adjustment unit also includes multiple power supply filter capacitors.

12. The tunnel borehole excitation polarization device according to claim 10, characterized in that, The sampling adjustment unit also includes a rectifier diode, which is connected between the other end of the sixth resistor and ground.

13. The tunnel borehole excitation polarization device according to claim 10, characterized in that, The sampling adjustment unit also includes a Zener diode, which is connected to the non-inverting input terminal of the third amplifier.

14. The tunnel borehole excitation polarization device according to claim 9, characterized in that, The constant current control module also includes a current limiting protection unit, which is used to limit the output current.

15. The tunnel borehole excitation polarization device according to claim 14, characterized in that, The current limiting protection unit includes a seventh resistor, a fourth amplifier, an eighth resistor, and an optocoupler. One end of the seventh resistor is connected to a current feedback resistor, and the other end of the seventh resistor is connected to the inverting input terminal of the fourth amplifier. The non-inverting input terminal of the fourth amplifier is connected to a current limiting voltage. One end of the eighth resistor is connected to the input terminal of the fourth amplifier, and the other end of the eighth resistor is connected to the optocoupler. When the voltage on the current feedback resistor exceeds the current limiting voltage, the optocoupler conducts, making the output voltage of the adjustable AC / DC voltage output unit 0.

16. The tunnel borehole excitation polarization device according to claim 1, characterized in that, The power supply control module's power supply bus includes a dual-channel A-electrode bus, a single-channel A-electrode bus, a dual-channel B-electrode bus, and a single-channel B-electrode bus. Multiple electrode arrays are connected to the dual-channel A-electrode bus, the single-channel A-electrode bus, the dual-channel B-electrode bus, and the single-channel B-electrode bus respectively through multiple power supply relay arrays.

17. The tunnel borehole excitation polarization device according to claim 16, characterized in that, The power supply control module also includes single / dual-channel control relays, which are used to control whether the dual-channel A-electrode bus and the dual-channel B-electrode bus are connected or whether the single-channel A-electrode bus and the single-channel B-electrode bus are connected.

18. The tunnel borehole excitation polarization device according to claim 16, characterized in that, The power supply control module also includes a direction relay, which is used to control the conduction direction of the dual-channel A-electrode bus and the dual-channel B-electrode bus, as well as the conduction direction of the single-channel A-electrode bus and the single-channel B-electrode bus.

19. The tunnel borehole excitation polarization device according to claim 16, characterized in that, The power supply control module also includes a grounding resistance relay, which is used for measuring grounding resistance.

20. The tunnel borehole excitation polarization device according to claim 16, characterized in that, The power supply control module also includes a fifth switch, a sixth switch, and a ninth resistor. One end of the fifth switch is connected to the constant current control module, and the other end of the fifth switch is connected to the directional relay. One end of the sixth switch is connected to the constant current control module through the ninth resistor. The acquisition module acquires the voltage across the ninth resistor to obtain the current signal.

21. The tunnel borehole excitation polarization device according to claim 20, characterized in that, The fifth and sixth switching transistors are MOS-FETs.

22. The tunnel borehole excitation polarization device according to claim 1, characterized in that, It also includes a power conversion module, which is used to supply power to other modules.

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