Induction-polarization effect targeted excitation method based on full-waveform current control

Abstract

The invention discloses an induction-polarization effect targeted excitation method based on full-waveform current control, and aims to respectively excite a polarization effect and an induction effect of an underground medium in a targeted manner by using a slow-rising and fast-turn-off combined emission current so as to realize high-precision detection. A polarization model is constructed based on geological data, optimal current parameters including rise time, fall time and the like are calculated, and target excitation parameters are preset in the master controller; aiming at a polarization effect, linear slow rising excitation of emission current is realized based on a direct current voltage regulation clamping module, and observation is carried out at a flat top section; and aiming at the induction effect, linear fast turn-off excitation of emission current is realized based on the energy feedback voltage regulation clamping module, and observation is carried out at the tail section after the current is completely turned off. According to the invention, in a unipolar period, the time domain electromagnetic response of the induction effect and the polarization effect is enhanced in a targeted manner, and the conductive and polarization information is obtained at the same time, so that the signal-to-noise ratio of polarization data and the exploration efficiency are improved, and time domain electromagnetic refined exploration is facilitated.

Description

Technical Field

[0001] This application belongs to the field of geophysical exploration, involves time-domain electromagnetic method exploration technology, and specifically relates to an induction-polarization effect targeted excitation method based on full-waveform current control. Background Technique

[0002] Due to its advantages such as fast speed, high efficiency, wide detection range, and low cost, the time-domain electromagnetic method has become an important method in the detection field. The basic principle of the existing time-domain electromagnetic transmitter is to generate a bipolar trapezoidal wave current in the transmitting coil with the transmitter, excite a primary pulse magnetic field, and during the interval of the primary magnetic field, measure the changing field of the induced electromagnetic field (secondary field) generated by the underground medium over time. The data of the collected secondary magnetic field (and its change rate) contains induction response and polarization response, and the resistivity and polarization rate can be jointly extracted.

[0003] The excitation time of the transmitted current affects the magnitude of the electromagnetic responses of the induction effect and the polarization effect. The shorter the excitation time, the stronger the electromagnetic response of the induction effect and the weaker the electromagnetic response of the polarization effect; the longer the excitation time, the weaker the electromagnetic response of the induction effect and the stronger the electromagnetic response of the polarization effect. Therefore, for the induction effect and the polarization effect of underground media, selecting different times for excitation and observing separately is conducive to distinguishing the response characteristics of the two and achieving targeted excitation. Joint parameter extraction of the electromagnetic responses of the two is conducive to identifying deep mineral information. Therefore, it is very necessary to perform targeted excitation for the induction-polarization effect of underground media.

[0004] Chinese Patent CN115951413A discloses a fast and slow turn-off targeted excitation method for the induction-polarization effect of an electrical source. By outputting a double-trapezoidal wave high-power transmitted current with two turn-off times within one period, the induction and polarization effects are enhanced respectively, and the exploration accuracy is improved. However, this method requires two trapezoidal waves with different turn-off times to excite the target body, and the efficiency is insufficient. Summary of the Invention

[0005] The technical problem to be solved by this application is an induction-polarization effect targeted excitation method based on full-waveform current control, which solves the problem that it is difficult to observe the induction effect and the polarization effect of underground media, and realizes targeted excitation of the induction effect and the polarization effect at different excitation times. At the same time, based on the full-waveform transmission control method, it solves the problems of overshoot or undershoot of the rising edge and non-constant current in the flat top section of the original transmitter, and realizes the full-waveform targeted excitation method of "rising edge excitation - flat top section observation, falling edge excitation - tail section observation". This application improves the signal-to-noise ratio of polarization data and exploration efficiency, which is conducive to the refined exploration of time-domain electromagnetics.

[0006] This application is realized through the following technical solutions:

[0007] A method for targeted excitation of induced-polarization effect based on full-waveform current control, the steps are as follows:

[0008] S1 According to the underground medium distribution and existing geological data, establish a generalized equivalent medium polarization (GEMTIP) model to characterize the induced-polarization effect of the multiphase conductive medium in the underground medium, and analyze the electromagnetic response characteristics at different excitation times based on the model to construct a targeted excitation relationship;

[0009] S2 Based on the polarization model, the power supply voltage U s , the impedance R and inductive reactance L of the transmitting bridge circuit and the transmitting load coil, calculate the optimal turn-on excitation time t0 and the optimal turn-off excitation time t1 in the targeted excitation relationship;

[0010] S3 For the polarization field, based on the DC voltage regulating and clamping module, realize the linear slow rise of the transmitting current, and control the rise time to the optimal turn-on excitation time t0 to target the excitation of the polarization effect;

[0011] S4 Observe the electromagnetic response of the polarization effect during the flat-top section of the transmitting current;

[0012] S5 For the induction field, based on the energy-feedback voltage regulating and clamping module, realize the linear fast turn-off of the transmitting current, and control the turn-off time to the optimal turn-off excitation time t1 to target the excitation of the induction effect;

[0013] S6 Observe the electromagnetic response of the induction effect during the tail section of the transmitting current.

[0014] Further, the optimal turn-on excitation time t0 in S2 is the turn-off time corresponding to the earliest sign reversal when the maximum negative response amplitude decays by 10% among the polarization characteristics in all response curves according to the calculation results of the induced-polarization electromagnetic responses at different turn-off times in the polarization model in S1. The polarization characteristics include: sign reversal time and maximum negative response amplitude;

[0015] The optimal turn-off excitation time t1 is the shortest turn-off time of the circuit, calculated by the following formula:

[0016]

[0017] where V off is the falling-edge clamping voltage value.

[0018] Further, the DC voltage regulating and clamping module and the energy-feedback voltage regulating and clamping module are arranged in the transmitter. The transmitter includes: a power supply, a combined clamping unit, a matching unit, a transmitting bridge circuit and a main controller. Among them, the combined clamping unit includes a DC voltage regulating and clamping module and an energy-feedback voltage regulating and clamping module, both of which are powered by the power supply.

[0019] The emission bridge circuit includes power IGBT devices Q1, Q2, Q3, and Q4, diodes D1, D2, and D3, and an emission load coil. The series-connected power IGBT devices Q1 and Q2 are in parallel with the series-connected power IGBT devices Q3 and Q4. The two ends of the parallel connection form the first end and the second end of the emission bridge circuit. One end of the power supply is connected to the first end through the series-connected diodes D1 and D2, and the first end is output through the diode D3. The second end of the emission bridge circuit is connected to the other end of the power supply. The emission bridge circuit forms a bipolar current according to the switching signal of the main controller. One end of the emission coil is connected between the power IGBT devices Q1 and Q2, and the other end is connected between the power IGBT devices Q3 and Q4.

[0020] The matching unit is connected to the emission bridge circuit and includes a series connection of a power IGBT device Q5, a power IGBT device Q6, and a resistive load. The emitters of the power IGBT devices Q5 and Q6 are both connected to the resistive load, and the two collectors are respectively connected between the power IGBT devices Q1 and Q2 and between the power IGBT devices Q3 and Q4. When the four power IGBT devices of the emission bridge circuit are turned off, the matching unit is connected to the circuit to absorb the tail overshoot of the emission current.

[0021] The main controller is a microprocessor that controls the switching devices of the emission bridge circuit to realize the power supply to the emission bridge circuit by the power supply and the combined clamping unit alternately.

[0022] The gates of the power IGBT devices are all controlled by the drive signals issued by the main controller to realize the conduction and turn-off of the power devices.

[0023] The DC voltage regulating and clamping module is connected in parallel across the two ends of the input of the power supply. One end of the energy feedback voltage regulating and clamping module is connected to the output end of the diode D3, and the other end is connected to the second end of the emission bridge circuit.

[0024] The DC voltage regulating and clamping module is designed based on the boost chopper technology. The DC voltage regulating and clamping module has four ports: input positive, input negative, output positive, and output negative. The input positive is connected to the positive pole of the power supply, the input negative and the output negative are both connected to the negative pole of the power supply, and the output positive is connected to the collector of the power device Q7. The emitter of the power device Q7 is connected between the diodes D1 and D2. The power device Q7 is turned on during the rising edge of the emission current to realize high-voltage clamping, so that the bipolar emission current rises linearly according to the preset rising time. The output of the DC voltage regulating and clamping module is in a constant voltage mode, and the output voltage is continuously adjustable.

[0025] The energy-feedback voltage-regulating clamping module includes an energy storage capacitor and an energy-feedback unit. The energy storage capacitor is a large-capacity capacitor bank, which is connected in parallel to the emitter of diode D3 and power IGBT device Q4. The energy-feedback unit includes three resistors connected in series. One of the resistors is a voltage-dividing resistor, and the adjustment terminal of the voltage-dividing resistor is connected to the non-inverting input terminal of a comparator. The inverting input terminal of the comparator is grounded, and the output terminal of the comparator is connected to the base of power device Q8. The emitter of power device Q8 is connected to the positive pole of the power supply through an energy-feedback resistor, and the collector of power device Q8 is connected to the positive pole of the energy storage capacitor;

[0026] During the falling edge, the current flows into the energy storage capacitor through diode D3, and the energy storage capacitor continuously absorbs energy to form a voltage to clamp the current. When the voltage of the energy storage capacitor exceeds the preset value, power device Q8 conducts, and the energy of the energy storage capacitor is fed back to the power supply through the energy-feedback resistor. The function of the energy-feedback resistor is to control the energy-feedback current.

[0027] Further, during the rising edge stage, the transmitter turns on power IGBT device Q1, power IGBT device Q4, and power device Q7 in the positive half-cycle, and turns on power IGBT device Q2, power IGBT device Q3, and power device Q7 in the negative half-cycle, connects the DC voltage-regulating clamping module to the transmitting bridge circuit, and the transmitting current is linearly clamped and rises;

[0028] During the flat top section, the value of the transmitting current reaches the optimal current value I best , power device Q7 is turned off, the DC voltage-regulating clamping module loses its function, and the power supply provides energy for the transmitting bridge circuit through diode D1 and diode D2, and the current enters the flat top constant value stage.

[0029] Further, during the falling edge stage, power IGBT device Q1 and power IGBT device Q4 are turned off in the positive half-cycle, and power IGBT device Q2 and power IGBT device Q3 are turned off in the negative half-cycle. The energy-feedback voltage-regulating clamping module is connected to the transmitting bridge circuit through diode D3 to linearly clamp the transmitting current;

[0030] At the end of the transmission, power IGBT device Q1, power IGBT device Q2, power IGBT device Q3, and power IGBT device Q4 are all turned off. Power IGBT device Q6 is turned on in the positive half-cycle, and power IGBT device Q5 is turned on in the negative half-cycle, and the matching unit is switched in to absorb the overshoot of the current tail.

[0031] Compared with the existing methods, the full-waveform targeted excitation method provided by this application has the following beneficial effects: within a single unipolar cycle, this application respectively targets and enhances the time-domain electromagnetic responses of the induction effect and the polarization effect, simultaneously obtains conductive and polarization information, improves the signal-to-noise ratio of polarization data and the exploration efficiency, and is conducive to time-domain electromagnetic fine exploration. Description of the Drawings

[0032] Figure 1 It is a flowchart of the full-waveform targeted excitation method provided by an embodiment of the present application;

[0033] Figure 2 It is a schematic structural diagram of a transmitter provided by an embodiment of the present application;

[0034] Figure 3 It is the transmitted current for linearizing different rise times provided by an embodiment of the present application;

[0035] Figure 4 It is the transmitted current for linearizing different fall times provided by an embodiment of the present application;

[0036] Figure 5 It is the electromagnetic response under different conduction time excitations provided by an embodiment of the present application;

[0037] Figure 6 It is the electromagnetic response under different turn-off time excitations provided by an embodiment of the present application. Specific implementation manners

[0038] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0039] An induction-polarization effect targeted excitation method based on full-waveform current control, see Figure 1 , the steps are as follows:

[0040] S1 According to the underground medium distribution situation and existing geological data, establish a generalized equivalent medium polarization (GEMTIP) model to characterize the induction-polarization effect of the multiphase conductive medium of the underground medium, and analyze the electromagnetic response characteristics of different excitation times according to the model to construct a targeted excitation relationship, where the targeted excitation relationship refers to the electromagnetic response characteristics corresponding to different excitation times;

[0041] S2 Based on the polarization model, power supply voltage U s , impedance R and inductive reactance L of the transmitting bridge circuit and the transmitting load coil, calculate the optimal turn-on excitation time t0 and the optimal turn-off excitation time t1 in the targeted excitation relationship;

[0042] S3 For the polarization field, based on the DC voltage regulation and clamping module, realize the linear slow rise of the transmitted current, control the rise time to the optimal turn-on excitation time t0, and target the excitation of the polarization effect;

[0043] S4 Observe the electromagnetic response of the polarization effect during the flat-top period of the transmitted current;

[0044] For the induction field, based on the energy-feeding voltage-regulating clamping module, the emission current is linearly and quickly turned off, and the turn-off time is controlled to be the optimal turn-off excitation time t1 to target and excite the induction effect.

[0045] S6 Observe the electromagnetic response of the induction effect during the tail time of the emission current.

[0046] This application is based on the full-waveform current emission control method and transmitter, which emits a bipolar trapezoidal wave with "both the rising edge and the falling edge being linear and adjustable, and both the flat top section and the tail section being constant" to achieve full-waveform targeted excitation and observation.

[0047] See Figure 2 , the transmitter includes a power supply, a combined clamping unit, a matching unit, an emission bridge circuit, and a main controller. The combined clamping unit includes a DC voltage-regulating clamping module and an energy-feeding voltage-regulating clamping module, both of which are powered by the power supply.

[0048] The emission bridge circuit includes power IGBT devices Q1, Q2, Q3, and Q4, diodes D1, D2, and D3, and an emission load coil. The series-connected power IGBT devices Q1 and Q2 are in parallel with the series-connected power IGBT devices Q3 and Q4. The two ends of the parallel connection form the first end and the second end of the emission bridge circuit. One end of the power supply is connected to the first end through the series-connected diodes D1 and D2, and the first end outputs through the diode D3. The second end of the emission bridge circuit is connected to the other end of the power supply; according to the switching signal of the main controller, the emission bridge circuit forms a bipolar current; one end of the emission coil is connected between the power IGBT devices Q1 and Q2, and the other end is connected between the power IGBT devices Q3 and Q4;

[0049] The matching unit is connected to the emission bridge circuit and includes the series connection of power IGBT devices Q5, Q6, and a resistive load. The emitters of the power IGBT devices Q5 and Q6 are both connected to the resistive load, and the two collectors are respectively connected between the power IGBT devices Q1 and Q2 and between the power IGBT devices Q3 and Q4; when the 4 power IGBT devices of the emission bridge circuit are turned off, the matching unit is connected to the circuit to absorb the tail overshoot of the emission current;

[0050] The main controller is a microprocessor. By controlling the switching devices of the emission bridge circuit through the main controller, the power supply and the combined clamping unit are alternately powered to the emission bridge circuit; the gates of the power IGBT devices are all controlled by the drive signals issued by the main controller to achieve the conduction and turn-off of the power devices.

[0051] The DC voltage regulating and clamping module is connected in parallel across the input terminals of the power supply. One end of the energy feedback voltage regulating and clamping module is connected to the output terminal of diode D3, and the other end is connected to the second terminal of the transmitting bridge circuit.

[0052] Among them, the DC voltage regulating and clamping module is designed based on the boost chopper technology. The module has four ports: input positive, input negative, output positive, and output negative. The input positive is connected to the power supply positive, both the input and output negative are connected to the power supply negative, and the output positive is connected to the collector of power device Q7. When the rising edge occurs, Q7 is turned on to achieve high-voltage clamping, enabling the bipolar emission current to linearly rise according to the preset rising time. The module output is in a constant voltage mode, and the output voltage is continuously adjustable.

[0053] The energy feedback voltage regulating and clamping module includes an energy storage capacitor and an energy feedback unit. The energy storage capacitor is a large-capacity capacitor bank connected in parallel across the emitter of diode D3 and power IGBT device Q4. The energy feedback unit includes three resistors connected in series. One of the resistors is a voltage-dividing resistor, and the adjustment terminal of the voltage-dividing resistor is connected to the non-inverting input terminal of a comparator. The inverting input terminal of the comparator is grounded, and the output terminal of the comparator is connected to the base of power device Q8. The emitter of power device Q8 is connected to the power supply positive through an energy feedback resistor, and the collector of power device Q8 is connected to the positive pole of the energy storage capacitor.

[0054] During the falling edge, the current flows into the energy storage capacitor through diode D3, and the energy storage capacitor continuously absorbs energy to form a voltage to clamp the current. When the voltage of the energy storage capacitor exceeds the preset value, power device Q8 is turned on, and the energy of the energy storage capacitor is fed back to the power supply through the energy feedback resistor. The role of the energy feedback resistor is to control the energy feedback current.

[0055] The transmitter in the embodiment of the present application can generate a time-domain electromagnetic full waveform. Under the full waveform bipolar trapezoidal wave of one positive and negative cycle:

[0056] During the rising edge stage, power IGBT device Q1, power IGBT device Q4, and power device Q7 are turned on in the positive half cycle, and power IGBT device Q2, power IGBT device Q3, and power device Q7 are turned on in the negative half cycle. The DC voltage regulating and clamping module is connected to the transmitting bridge circuit, and the emission current linearly clamps and rises.

[0057] During the flat top section, the emission current value reaches the optimal current value I best , power device Q7 is turned off, and the DC voltage regulating and clamping module loses its function. Instead, the power supply provides energy to the transmitting bridge circuit through diode D1 and diode D2, and the current enters the flat top constant value stage.

[0058] During the falling edge stage, the power IGBT devices Q1 and Q4 are turned off in the positive half-cycle, and the power IGBT devices Q2 and Q3 are turned off in the negative half-cycle. The energy feedback voltage clamping module is connected to the transmitting bridge circuit through the diode D3 to linearly clamp the transmitting current.

[0059] At the end of the transmission, the power IGBT devices Q1, Q2, Q3, and Q4 are all turned off. The power IGBT device Q6 is turned on in the positive half-cycle, and the power IGBT device Q5 is turned on in the negative half-cycle, and the matching unit is switched in to absorb the overshoot of the current tail.

[0060] In this application, the optimal turn-on excitation time t0 is the turn-off time corresponding to the earliest sign inversion moment when the maximum negative response amplitude decays by 10% among the polarization characteristics in all response curves, which is calculated based on the induced-polarization electromagnetic response with different turn-off times. The polarization characteristics include: the sign inversion moment and the maximum negative response amplitude.

[0061] The optimal turn-off excitation time t1 is the shortest turn-off time of the circuit and is calculated by the following formula:

[0062]

[0063] where V off is the falling edge clamping voltage value.

[0064] Based on the time-domain electromagnetic full-waveform emission control method with active double clamping proposed in this application, the relevant methods are simulated in software and verified. Here is a set of verification cases. The power supply voltage is 24V, the emission load has a resistance of 0.3 ohms and an inductance of 3mH. The boost module is based on BOOST boost technology, and the output voltage range is linearly adjustable from 48V to 72V. The capacitor is a 10000uF electrolytic capacitor, and the clamping voltage value is linearly adjustable from 24V to 120V. Considering parameters such as line stray resistance and diode voltage drop, the optimal current amplitude is about 16A at this time.

[0065] According to the above-mentioned simulation, see Figure 3 , by adjusting the boost adjustable clamping voltage value, three different rise times of 200μs, 300μs, and 500μs are achieved at the same emission current amplitude, and the clamping voltage values are 70V, 55V, and 45.5V respectively; see Figure 4 , by adjusting the energy feedback adjustable clamping voltage value, three different turn-off times of 90μs, 140μs, and 260μs are achieved at the same emission current amplitude, and the clamping voltage values are 99V, 72.5V, and 50.1V respectively.

[0066] Full waveform three-dimensional numerical simulation method of induced polarization effect based on time domain diffusion equation, electromagnetic responses with different on-time and off-time are calculated respectively. For the results of the dual coordinate systems of the responses, see Figure 5 It can be seen that the longer the rise time is, the earlier the sign inversion moment of the polarization effect observed in the flat top section is, which is more conducive to observing the polarization effect. For the electromagnetic responses of the induced effect under different off-time excitations, see Figure 6 , it can be seen that the longer the off-time is, the earlier the sign inversion moment of the induced effect observed in the flat top section is, which is more conducive to observing the induced effect.

[0067] The above are only the preferred embodiments of the present application, and are not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An induction-polarization effect targeted excitation method based on full-waveform current control, characterized in that The steps are as follows: S1 According to the distribution of underground media and existing geological data, a generalized equivalent medium polarization model is established to characterize the induction-polarization effect of multi-phase conductive media in underground media. Based on the model, the electromagnetic response characteristics at different excitation times are analyzed, and a targeted excitation relationship is constructed; S2 calculates the optimal turn-on excitation time t0 and the optimal turn-off excitation time t1 in the targeted excitation relationship based on the polarization model, the power supply voltage U s , the impedance R and inductive reactance L of the transmitting bridge circuit and the transmitting load coil; S3 For the polarization field, based on the DC voltage regulating and clamping module, the transmitted current is linearly increased slowly, and the rising time is controlled to be the optimal turn-on excitation time t0 to target the excitation of the polarization effect; S4 Observe the electromagnetic response of the polarization effect during the flat-top section of the transmitted current; S5 For the induction field, based on the energy-fed voltage regulating and clamping module, the transmitted current is linearly turned off quickly, and the turn-off time is controlled to be the optimal turn-off excitation time t1 to target the excitation of the induction effect; S6 Observe the electromagnetic response of the induction effect during the tail section of the transmitted current.

2. The induction-polarization effect targeted excitation method based on full-waveform current control according to claim 1, characterized in that The optimal turn-on excitation time t0 in S2 is the turn-off time corresponding to the earliest sign reversal when the maximum negative response amplitude decays by 10% among the polarization characteristics in all response curves according to the calculation results of the induction-polarization electromagnetic response at different turn-off times in the polarization model in S1. The polarization characteristics include: sign reversal time and maximum negative response amplitude; The optimal turn-off excitation time t1 is the shortest turn-off time of the circuit and is calculated by the following formula: where V off is the falling-edge clamping voltage value.

3. The induction-polarization effect targeted excitation method based on full-waveform current control according to claim 1, wherein The DC voltage regulating and clamping module and the energy-fed voltage regulating and clamping module are arranged in the transmitter. The transmitter includes: a power supply, a combined clamping unit, a matching unit, a transmitting bridge circuit, and a main controller. Among them, the combined clamping unit includes a DC voltage regulating and clamping module and an energy-fed voltage regulating and clamping module, both of which are powered by the power supply. The transmitting bridge circuit includes power IGBT devices Q1, Q2, Q3, and Q4, diodes D1, D2, and D3, and a transmitting load coil. The series-connected power IGBT devices Q1 and Q2 are in parallel with the series-connected power IGBT devices Q3 and Q4. The two ends of the parallel connection form the first end and the second end of the transmitting bridge circuit. One end of the power supply is connected to the first end through the series-connected diodes D1 and D2, and the first end is output through the diode D3. The second end of the transmitting bridge circuit is connected to the other end of the power supply; according to the switching signal of the main controller, the transmitting bridge circuit forms a bipolar current; one end of the transmitting coil is connected between the power IGBT devices Q1 and Q2, and the other end is connected between the power IGBT devices Q3 and Q4; The matching unit is connected to the transmitting bridge circuit and includes a series connection of power IGBT devices Q5, Q6, and a resistive load. The emitters of the power IGBT devices Q5 and Q6 are both connected to the resistive load, and the two collectors are respectively connected between the power IGBT devices Q1 and Q2 and between the power IGBT devices Q3 and Q4; when the 4 power IGBT devices of the transmitting bridge circuit are turned off, the matching unit is connected to the circuit to absorb the tail overshoot of the transmitted current; The main controller is a microprocessor, which controls the switching devices of the transmitting bridge circuit to realize the power supply to the transmitting bridge circuit by the power supply and the combined clamping unit alternately. The gates of the power IGBT devices are all controlled by the driving signals sent by the main controller to realize the conduction and cut-off of the power devices. The DC voltage regulating and clamping module is connected in parallel at both ends of the input terminal of the power supply. One end of the energy feedback voltage regulating and clamping module is connected to the output terminal of diode D3, and the other end is connected to the second end of the transmitting bridge circuit. The DC voltage regulating and clamping module is designed based on the boost chopper technology. The DC voltage regulating and clamping module has four ports: input positive pole, input negative pole, output positive pole and output negative pole. The input positive pole is connected to the positive pole of the power supply, the input negative pole and the output negative pole are both connected to the negative pole of the power supply, and the output positive pole is connected to the collector of power device Q7. The emitter of power device Q7 is connected between diode D1 and diode D2. When the rising edge of the emission current occurs, power device Q7 is turned on to realize high-voltage clamping, so that the bipolar emission current rises linearly according to the preset rising time. The output of the DC voltage regulating and clamping module is in a constant voltage mode, and the output voltage is continuously adjustable. The energy feedback voltage regulating and clamping module includes an energy storage capacitor and an energy feedback unit. The energy storage capacitor is a large-capacity capacitor bank, which is connected in parallel between diode D3 and the emitter of power IGBT device Q4. The energy feedback unit includes three resistors connected in series. One of the resistors is a voltage dividing resistor. The adjusting end of the voltage dividing resistor is connected to the non-inverting input terminal of a comparator. The inverting input terminal of the comparator is grounded. The output terminal of the comparator is connected to the base of power device Q8. The emitter of power device Q8 is connected to the positive pole of the power supply through an energy feedback resistor. The collector of power device Q8 is connected to the positive pole of the energy storage capacitor. When the falling edge occurs, the current flows into the energy storage capacitor through diode D3, and the energy storage capacitor continuously absorbs energy to form a voltage to clamp the current. When the voltage of the energy storage capacitor exceeds the preset value, power device Q8 is turned on, and the energy of the energy storage capacitor is fed back to the power supply through the energy feedback resistor. The function of the energy feedback resistor is to control the energy feedback current.

4. The induced-polarization effect targeted excitation method based on full-waveform current control according to claim 3, characterized in that In the rising edge stage, the transmitter turns on power IGBT device Q1, power IGBT device Q4 and power device Q7 in the positive half cycle, and turns on power IGBT device Q2, power IGBT device Q3 and power device Q7 in the negative half cycle, connects the DC voltage regulating and clamping module to the transmitting bridge circuit, and the emission current is linearly clamped and rises. In the flat-top section, the emission current value reaches the optimal current value I best , the power device Q7 is turned off, and the DC voltage regulating and clamping module loses its function. Instead, the power supply provides energy for the emission bridge circuit through diode D1 and diode D2, and the current enters the flat-top constant value stage.

5. The induction-polarization effect targeted excitation method based on full-waveform current control according to claim 3, characterized in that In the falling edge stage, power IGBT device Q1 and power IGBT device Q4 are turned off in the positive half cycle, and power IGBT device Q2 and power IGBT device Q3 are turned off in the negative half cycle. The energy feedback voltage regulating and clamping module is connected to the transmitting bridge circuit through diode D3 to linearly clamp the emission current. At the end of the emission, power IGBT device Q1, power IGBT device Q2, power IGBT device Q3 and power IGBT device Q4 are all turned off. Power IGBT device Q6 is turned on in the positive half cycle, and power IGBT device Q5 is turned on in the negative half cycle, and the matching unit is switched in to absorb the overshoot of the current tail.

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