Electromagnetic exploration emission system that overcomes the effects of load inductance

Abstract

To provide an electromagnetic exploration emission system that overcomes effects of a load inductance.SOLUTION: An electromagnetic exploration emission system includes an emission circuit and a logic control circuit. The emission circuit is used to emit a high frequency high current, and the logic control circuit is used to generate a drive signal for a switching device in the emission circuit. By connecting the current rapid on / off unit in series with the emission circuit, introducing an auxiliary on / off voltage, and forming a current high voltage emission circuit with a series connection of a plurality of on / off units, the limitation due to a rated voltage of the power device is overcome, and the rapid on / off of the emission current under the large inductive load condition is achieved.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] This invention belongs to the field of physical technology for Earth exploration, and more specifically, relates to an electromagnetic exploration emission system that overcomes the effects of load inductance. [Background technology]

[0002] Electromagnetic methods utilize the differences in electromagnetic properties such as electrical conductivity and permeability of underground media, applying the principle of electromagnetic induction to observe and study the distribution rules (frequency characteristics or temporal characteristics) of artificially or naturally formed electromagnetic fields, thereby solving related geological problems. Artificial sources overcome the drawback of natural sources, which have a low signal-to-noise ratio, and significantly improve working efficiency, detection accuracy, and detection resolution. Controllable source audio geomagnetic methods, wide-area electromagnetic methods, semi-aerial electromagnetic methods, short-offset transient electromagnetic methods, and time-frequency electromagnetic methods inject current into the ground using long wiring (1km-2km) and grounding electrodes to excite artificial electric field sources. Full-aerial electromagnetic methods and ground transient electromagnetic methods excite artificial magnetic field sources using large coil currents.

[0003] Artificial sources excited by rapidly changing currents can improve detection accuracy and resolution, and enhance the effectiveness of high-frequency data. Long wiring inductances used to excite artificial electric field sources hinder current changes, preventing efficient emission of high-frequency currents. Controllable source audio geomagnetic methods based on audio currents cannot observe data over long transmission and reception distances, affecting detection depth. Wide-area electromagnetic methods based on pseudo-random code currents cannot achieve the multi-frequency and equiamplitude large current emission required for method theory, affecting detection accuracy. Short-offset and semi-aviation electromagnetic methods based on secondary magnetic field attenuation signal observations cannot obtain reliable initial apparent resistivity data, affecting detection resolution. Exciting an artificial magnetic field source to obtain a large coil inductance also hinders current changes, preventing the realization of rapid current changes.

[0004] Internationally mainstream electromagnetic transmitter products include the TXU-30 transmitter from Phoenix Geophysics of Canada, the GGT-30 transmitter from Zonge of the United States, and the TXM-22 transmitter from Metronix of Germany. In China, existing domestic and international transmitters such as the GDC-1 transmitter developed by Professor He Jishan's team at Central South University based on the broad-area electromagnetic method, the DEM-T70 transmitter developed by the Institute of Geophysics and Geochemical Exploration (IGGE) of the Chinese Academy of Geological Sciences, the JDD-100 transmitter developed by Jilin University, the 50kW transmitter developed by Beijing University of Technology, the 160kW transmitter developed by China University of Geosciences (Beijing), the 200kW transmitter developed by PetroChina Oriental Geophysics Company, and the 30kW transmitter developed by Chengdu University of Technology have not been able to overcome the effect of load inductance on the emitted current. With the development of electromagnetic exploration, the problem of overcoming the effect of load inductance on the emitted current is attracting increasing attention and has become an important research direction for electromagnetic transmitters.

[0005] Regarding research on current-off technology, specifically the control of emission current from large coil magnetic sources, China University of Geosciences (Wuhan) proposed a concept to increase the equivalent resistance of the discharge circuit. By controlling the circuit inductance to 1.2 mH, the emission current to 10 A, and the discharge circuit resistance to 50 Ω, the current-off time is reduced from 1.3 ms to approximately 100 μs. The emission scheme of energy-supplied constant-current constant-voltage clamp technology proposed by the Institute of Electronics, Chinese Academy of Sciences, rapidly reduces induced reflux through a high-voltage clamp unit and feeds it back to the high-voltage power supply. Jilin University has studied a control method using a PWM chopper and constant-voltage clamp and proposed compensatory control of time-frequency fused emission. Existing technologies typically yield off times of several hundred μs or more. Power sources with long wiring have stronger storage and longer descent times. For rapid off-current of emission current from power sources with long wiring, currently reported literature achieves an off-time of 53 μs under the condition of a 1 km long wiring. There are currently few reports in the relevant literature regarding rapid current-on.

[0006] Conventional techniques have focused on applying high-voltage clamps to the discharge bridge to overcome the influence of inductance on discharge current. However, this method is limited by the voltage withstand capability of the power device and cannot cope with rapid current changes in various construction environments. Furthermore, the concentration of overvoltages in the transmitter poses a significant risk and reduces system reliability. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] To address the shortcomings of the prior art, this invention proposes an electromagnetic exploration emission system that overcomes the influence of load inductance, overcomes the voltage withstand limitations of power devices, distributes the high-voltage portion to the emission circuit through a current on / off unit, and applies auxiliary high voltage to the circuit at the moment the current changes, forcing a rapid change in current. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides the following solutions.

[0009] An electromagnetic exploration emission system that overcomes the effects of load inductance, comprising an emission circuit and a logic control circuit, The discharge circuit is used to discharge high-frequency, high-current, The logic control circuit is used to generate drive signals for the switching devices in the emission circuit.

[0010] Preferably, the discharge circuit includes a discharge power supply, a long wiring inductance, an electrode resistor, a discharge bridge, and a current high-voltage discharge circuit. The aforementioned discharge power supply is used to supply power to the discharge system. The emission bridge consists of four IGBTs: K1, K2, K3, and K4. The current high-voltage discharge circuit consists of a first on / off unit and a second on / off unit connected in series.

[0011] Preferably, in the emission circuit, The positive electrode of the discharge power supply is connected to the collector of K1 and the collector of K3 respectively, The negative electrode of the discharge power supply is connected to the emitter of K2 and the emitter of K4 respectively, The emitter of K1 is connected to the collector of K2 and is wired to one side of the first on-off unit, The emitter of K3 is connected to the collector of K4 and is wired to one side of the long wiring inductance, The opposite side of the long wiring inductance is connected to one side of the electrode resistance, The opposite side of the electrode resistance is connected to one side of the second on-off unit.

[0012] Preferably, the first on-off unit includes a first on-off bridge, a first on-off power supply, and a first on-off switch, The first on-off bridge is composed of four IGBTs, S11, S12, S13, and S14, The first on-off switch is composed of a series connection of two IGBTs. One side of the first on-off switch is connected to the discharge circuit, and the opposite side of the first on-off switch is connected to the second on-off unit, The positive electrode of the first on-off power supply is connected to the collector of S11 and the collector of S13 respectively, The negative electrode of the first on-off power supply is connected to the emitter of S12 and the emitter of S14 respectively, The emitter of S11 is connected to the collector of S12 and is wired to one side of the first on-off switch, The emitter of S13 is connected to the collector of S14 and is wired to the opposite side of the first on-off switch.

[0013] Preferably, the second on-off unit includes a second on-off bridge, a second on-off power supply, and a second on-off switch, The second on-off bridge is composed of four IGBTs, S21, S22, S23, and S24, The second on / off switch consists of two IGBTs connected in series, with one side of the second on / off switch connected to the first on / off unit and the other side of the first on / off switch connected to the electrode resistor. The positive terminals of the second on / off power supply are connected to the collectors of S21 and S23, respectively. The negative terminals of the second on / off power supply are connected to the emitters of S22 and S24, respectively. The emitter of S21 is connected to the collector of S22 and wired to one side of the second on / off switch. The emitter of S23 is connected to the collector of S24 and wired to the opposite side of the second on / off switch.

[0014] Preferably, the logic control circuit includes a current sensor, an on / off bridge drive circuit, and an emission bridge drive circuit. The current sensor is provided between the emission power supply and the emission bridge, connected to the on / off bridge drive circuit, and is used to collect the current signal of the emission power supply. The emission bridge drive circuit further includes an OR logic gate, The on / off bridge drive circuit includes a diode, a ground capacitor, a comparator, a first AND logic gate, and a second AND logic gate.

[0015] Preferably, the emission bridge drive circuit is used to generate drive signal A and drive signal B. The drive signal A is used to drive K1 and K4, and the drive signal B is used to drive K2 and K3. By connecting the drive signal A and the drive signal B to the OR logic gate, an on / off switch drive signal is generated, and the on / off switch drive signal is used to drive the first on / off switch and the second on / off switch.

[0016] Preferably, in the on / off bridge drive circuit: The current sensor is connected to the anode of the diode, The same-direction input terminal of the comparator is connected to the cathode of the diode and grounded via the ground capacitor. The inverting input terminal of the comparator is connected to the current sensor. The output terminals of the comparator are connected to the first AND logic gate and the second AND logic gate, respectively. After the drive signal A and the output of the comparator are processed by the first AND logic gate, the output signal is used to drive S11, S14, S21, and S24. After the drive signal B and the output of the comparator are processed by the second AND logic gate, the output signal is used to drive S12, S13, S22, and S23. [Effects of the Invention]

[0017] Compared to the conventional technology, the beneficial effects of the present invention are as follows:

[0018] This invention overcomes the limitations imposed by the rated voltage of power devices and enables rapid on / off switching of discharge current under large inductive load conditions by connecting a rapid current on / off unit (with no limit on the number of units) in series with a discharge circuit, introducing an auxiliary on / off voltage, and forming a high-voltage current discharge circuit by connecting multiple on / off units in series. [Brief explanation of the drawing]

[0019] To more clearly illustrate the technical solutions of the present invention, the drawings required for the embodiments are briefly described below. The drawings in the following description represent only a few embodiments of the present invention, and it will be apparent to those skilled in the art that other drawings can be obtained from these drawings without any creative effort. [Figure 1] This is a schematic diagram of a basic emission inverter bridge topology. [Figure 2] This is a schematic diagram of an inverter bridge that introduces off-high voltage. [Figure 3] This is a schematic diagram showing the circuit connection of an embodiment of the present invention that incorporates a single rapid current on / off circuit unit. [Figure 4] This is a schematic diagram showing the circuit connection of an embodiment of the present invention that incorporates two current rapid on / off circuit units. [Figure 5a] This is a schematic diagram comparing a current discharge waveform according to an embodiment of the present invention with a conventional current discharge waveform, and represents a current waveform in the frequency domain. [Figure 5b] This is a schematic diagram comparing a current discharge waveform according to an embodiment of the present invention with a conventional current discharge waveform, and is a current waveform in the time domain. [Figure 6] This is a schematic diagram showing the relationship between the number of on / off units according to an embodiment of the present invention and the multiplier used to speed up current on. [Figure 7] This is a schematic diagram showing the relationship between the number of on / off units according to an embodiment of the present invention and the magnification factor for speeding up current off. [Modes for carrying out the invention]

[0020] The technical solutions in embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings of embodiments of the present invention, but it is clear that the embodiments described are only some embodiments of the present invention and not all embodiments. All other embodiments obtained based on embodiments of the present invention, assuming that those skilled in the art do not perform any creative work, are within the scope of the present invention.

[0021] To make the above-mentioned objectives, features, and advantages of the present invention clearer and easier to understand, the present invention will be described in more detail below with reference to the drawings and specific embodiments.

[0022] Before describing the embodiments, let's first introduce existing technical solutions.

[0023] The load of the transmitter is mainly determined by the wiring inductance and the ground resistance. The conventional discharge bridge topology is shown in Fig. 1.

[0024] U is the discharge voltage (usually 1000V). K1, K2, K3, K4 are IGBT inverter bridge switches, L LOAD is the wiring inductance, R LOAD is the ground resistance. When K1 and K4 (or K2 and K3) turn on, the discharge current is restricted by the long wiring inductance and gradually rises to the steady value U DC / R LOAD :

[0025]

Number

[0026] Assume that the discharge current reaches the steady value I o =U DC / R LOAD and define the time for the current to rise to 90% of the steady current as the current on-time: <000018​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​​

[0032] When the current is 0, what is the desired off-time t? off It will be as follows:

[0033]

number

[0034] Therefore, the current on / off time is proportional to the discharge steady current and inversely proportional to the applied voltage. In this case, U DC This becomes the on / off voltage, U DC The higher the voltage, the faster the current turns off. At the construction site, after electrode treatment, L LOAD Wiring inductance and R LOAD Grounding resistance is almost uncontrollable, and rapid current switching can only be achieved by increasing the on / off voltage. Therefore, as shown in Figure 2, the conventional method introduces a rapid off topology of high-voltage clamping, applying high voltage to the discharge inverter bridge at the point of current switching to shorten the off time.

[0035] U DC The normal discharge voltage is 1000V, and P is the on / off high voltage at 2500V. When K5 is turned on at the on / off point and P is applied to the inverter bridge, equations (2) to (5) show that this method shortens the current on / off time. However, this method is limited by the device withstand voltage of the inverter bridge and is affected by the limitations of the construction environment.

[0036] Embodiment 1

[0037] In this embodiment, a rapid current on / off unit is connected in series to the discharge circuit, an auxiliary on / off voltage is introduced, and a high-voltage current discharge circuit is formed by connecting multiple on / off units in series. This overcomes the limitations imposed by the rated voltage of the power device and enables the rapid on / off of the discharge current under large inductive load conditions. By distributing the high voltage to the discharge circuit and keeping the voltage of the on / off unit low, the voltage withstand capability limit of the power device is avoided, ensuring system stability and reliability. The circuit topology is shown in Figure 3.

[0038] When the discharge current is activated, the discharge bridge diagonal switching device conducts, the on / off switch S in the on / off unit turns off, the on / off bridge diagonal switching device conducts, and the discharge current returns to a steady state I. o =U DC / R LOAD It remains off until it reaches a certain value, at which point the on / off switch S conducts. When the discharge current reverses, the other diagonal switching devices in the discharge bridge conduct, the on / off switch S in the on / off unit turns off, the other diagonal switching devices in the on / off bridge conduct, and the discharge current reaches the steady-state value -I o =-U DC / R LOAD The unit remains off until a certain value is reached, at which point the on / off switch S becomes conductive. By repeating this process, the objective of rapidly commutating a high current voltage can be achieved, and the current commutation voltage can be increased by connecting multiple on / off units in series until the commutation time reaches the target value.

[0039] Embodiment 2

[0040] In this embodiment, as shown in Figure 4, the electromagnetic exploration emission system that overcomes the effects of load inductance includes an emission circuit and a logic control circuit.

[0041] The discharge circuit is used to discharge high-frequency, high-current circuits. The discharge circuit is powered by a discharge power supply U DC , long wiring inductance L LOAD , electrode resistance R LOAD Includes a discharge bridge, a current high-voltage discharge circuit, and a discharge power supply U DCIt is used to supply power to the discharge system, and the discharge bridge consists of four IGBTs, K1, K2, K3, and K4, and the current high-voltage discharge circuit consists of a series connection of a first on-off unit and a second on-off unit.

[0042] In the emission circuit, the emission power supply U DC The positive terminals of the two are connected to the collectors of K1 and K3, respectively, and the emission power supply U DC The negative terminals of the two are connected to the emitters of K2 and K4 respectively, the emitter of K1 is connected to the collector of K2 and wired to one side of the first on / off unit, the emitter of K3 is connected to the collector of K4 and the long wire inductance L LOAD Wired to one side, with a long wiring inductance L LOAD The opposite side has an electrode resistance R LOAD It is connected to one side of the electrode resistance R LOAD The other end is connected to one side of the second on / off unit.

[0043] The first on / off unit includes a first on / off bridge, a first on / off power supply P1, and a first on / off switch S1, the first on / off bridge is composed of four IGBTs S11, S12, S13, and S14, the first on / off switch S1 is composed of two IGBTs connected in series, the emitters of these two IGBTs are connected and the collectors of each are used as the terminals of the first on / off unit, one side of the first on / off switch S1 is connected to the emission circuit, and The opposite side of the first on / off switch S1 is connected to the second on / off unit, the positive terminals of the first on / off power supply P1 are connected to the collectors of S11 and S13 respectively, the negative terminals of the first on / off power supply P1 are connected to the emitters of S12 and S14 respectively, the emitter of S11 is connected to the collector of S12 and wired to one side of the first on / off switch S1, the emitter of S13 is connected to the collector of S14 and wired to the opposite side of the first on / off switch S1.

[0044] The second on / off unit includes a second on / off bridge, a second on / off power supply P2, and a second on / off switch S2. The second on / off bridge consists of four IGBTs S21, S22, S23, and S24. The second on / off switch S2 consists of two IGBTs connected in series. The emitters of these two IGBTs are connected, and their collectors are used as the terminals of the second on / off unit. One side of the second on / off switch S2 is connected to the first on / off unit, and the other side of the first on / off switch S1 is connected to an electrode resistor R. LOAD The positive terminal of the second on / off power supply P2 is connected to the collector of S21 and the collector of S23, respectively, and the negative terminal of the second on / off power supply P2 is connected to the emitter of S22 and the emitter of S24, respectively. The emitter of S21 is connected to the collector of S22 and wired to one side of the second on / off switch S2, and the emitter of S23 is connected to the collector of S24 and wired to the other side of the second on / off switch S2.

[0045] The logic control circuit is used to generate the drive signals for the switching devices within the emission circuit.

[0046] The logic control circuit includes a current sensor, an on / off bridge drive circuit, and an emission bridge drive circuit. The current sensor is placed between the emission power supply and the emission bridge and connected to the on / off bridge drive circuit. The current sensor is used to collect the current signal from the emission power supply. The emission bridge drive circuit further includes an OR logic gate OR. The on / off bridge drive circuit includes a diode D, a ground capacitor C, a comparator COM, a first AND logic gate AND1, and a second AND logic gate AND2.

[0047] Here, an emission bridge drive circuit is used to generate drive signals A and B, drive signal A is used to drive K1 and K4, and drive signal B is used to drive K2 and K3. Drive signals A and B are connected to an OR logic gate OR to generate an on / off switch drive signal, which is used to drive a first on / off switch S1 and a second on / off switch S2.

[0048] In the on / off bridge drive circuit, the current sensor is connected to the anode of diode D, the same-direction input terminal of comparator COM is connected to the cathode of diode D and grounded to ground C via a ground capacitor, the inverting input terminal of comparator COM is connected to the current sensor, and the output terminals of comparator COM are connected to the first AND logic gate AND1 and the second AND logic gate AND2, respectively. After the drive signal A and the output of comparator COM are processed by the first AND logic gate AND1, the output signal is used to drive S11, S14, S21 and S24, and after the drive signal B and the output of comparator COM are processed by the second AND logic gate AND2, the output signal is used to drive S12, S13, S22 and S23.

[0049] In this embodiment, the on / off unit is set to 3000V, the emission voltage to 1000V, the load resistance to 50Ω, the load inductance to 3mH, and the steady-state emission current to 20A. 20A is used as the reference current and is the positive input to the comparator. The DC bus current is used as the negative input to the comparator. The output of the comparator is used as one input to two AND gates, AND1 and AND2, and the other input to the AND gate is connected to the two drive signals of the emission bridge. The outputs of the AND gates drive the two diagonal switches of the on / off unit, respectively. The two drive signals of the emission bridge are used as the inputs to an OR gate, and the output of the OR gate is connected to the main switch of the on / off unit. The frequency of the current waveform in the frequency domain of the electromagnetic method is calculated to be 10kHz, and the frequency of the current waveform in the time domain is calculated to be 1kHz. Figure 5 shows a comparison of the current emission waveform using the present invention technology with a conventional current emission waveform.

[0050] As can be seen from the simulation results, the commutation time of the output current waveform of the present invention is significantly reduced, and the current waveform in the frequency domain quickly enters a steady state of 20A. However, the commutation time of the conventional discharge current is too long, and it does not yet enter a steady state of 20A before being forcibly commutated, resulting in a very small discharge active current. The current waveform in the time domain turns on and off rapidly, giving the discharge current waveform technology a very strong advantage compared to conventional methods.

[0051] Embodiment 3

[0052] In this embodiment, the number of on / off units can be increased indefinitely, thereby achieving the objective of increasing the current commutation voltage, and increasing the number of on / off units connected in series until the indicator requirement is met, according to the demand for current on / off time.

[0053] The technical effect of using N on / off units will be verified using an equation.

[0054] If the discharge voltage and the voltage of the on / off unit are equal, and the number of on / off units is N, then the current on time can be inferred from equation (1) as follows:

[0055]

number

[0056] Normalize the on-time without the on / off unit and obtain a multiplier parameter that speeds up the current on-time of the on / off unit:

[0057]

number

[0058] The current off-time is as follows:

[0059]

number

[0060] Normalize the off time under conditions without an on / off unit, and obtain a multiplier parameter that speeds up the current off of the on / off unit:

[0061]

number

[0062] From the above equations, we can obtain the relationship between the number of on / off units and the multiplier that speeds up current on, as shown in Figure 6, and the relationship between the number of on / off units and the multiplier that speeds up current off, as shown in Figure 7. It can be seen that when on / off units are added, the on / off time of the current is rapidly shortened, and as the number of on / off units increases, the rate of shortening gradually slows down.

[0063] The embodiments described above merely illustrate preferred aspects of the present invention and do not limit the scope of the invention. Any modifications or improvements made by those skilled in the art to the technical solutions of the present invention, without departing from the spirit of the invention, shall fall within the scope of protection defined by the claims of the present invention.

Claims

1. An electromagnetic exploration emission system that overcomes the effects of load inductance, It includes an emission circuit and a logic control circuit, The discharge circuit is used to discharge high-frequency, high-current, The logic control circuit is used to generate a drive signal for the switching device in the emission circuit. The discharge circuit includes a discharge power supply, a long wiring inductance, an electrode resistor, a discharge bridge, and a current high-voltage discharge circuit. The emission power supply is used to power the electromagnetic exploration emission system that overcomes the effects of the load inductance. The aforementioned emission bridge consists of four IGBTs: K1, K2, K3, and K4. An electromagnetic exploration emission system that overcomes the influence of load inductance, characterized in that the current high-voltage emission circuit is composed of a series connection of a first on-off unit and a second on-off unit.

2. In the aforementioned discharge circuit, The positive electrode of the aforementioned power supply is connected to the collector of K1 and the collector of K3, respectively. The negative terminal of the discharge power supply is connected to the emitter of K2 and the emitter of K4, respectively. The emitter of K1 is connected to the collector of K2 and wired to one side of the first on / off unit. The emitter of K3 is connected to the collector of K4 and is wired to one side of the long wiring inductance. The other end of the long wiring inductance is connected to one side of the electrode resistance, The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 1, characterized in that the opposite side of the electrode resistance is connected to one side of the second on / off unit.

3. The first on / off unit includes a first on / off bridge, a first on / off power supply, and a first on / off switch. The first on / off bridge is composed of four IGBTs S11, S12, S13, and S14. The first on / off switch consists of two IGBTs connected in series, with one side of the first on / off switch connected to the emission circuit and the other side of the first on / off switch connected to the second on / off unit. The positive terminal of the first on / off power supply is connected to the collector of S11 and the collector of S13, respectively. The negative terminal of the first on / off power supply is connected to the emitter of S12 and the emitter of S14, respectively. The emitter of S11 is connected to the collector of S12 and wired to one side of the first on / off switch. The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 1, characterized in that the emitter of S13 is connected to the collector of S14 and wired to the opposite side of the first on / off switch.

4. The second on / off unit includes a second on / off bridge, a second on / off power supply, and a second on / off switch. The second on / off bridge is composed of four IGBTs, S21, S22, S23, and S24. The second on / off switch consists of two IGBTs connected in series, one side of the second on / off switch is connected to the first on / off unit, and the other side of the first on / off switch is connected to the electrode resistor. The positive terminals of the second on / off power supply are connected to the collectors of S21 and S23, respectively. The negative terminals of the second on / off power supply are connected to the emitters of S22 and S24, respectively. The emitter of S21 is connected to the collector of S22 and wired to one side of the second on / off switch. The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 3, characterized in that the emitter of S23 is connected to the collector of S24 and wired to the opposite side of the second on / off switch.

5. The logic control circuit includes a current sensor, an on / off bridge drive circuit, and an emission bridge drive circuit. The current sensor is provided between the emission power supply and the emission bridge, connected to the on / off bridge drive circuit, and is used to collect the current signal of the emission power supply. The emission bridge drive circuit further includes an OR logic gate, The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 4, characterized in that the on / off bridge drive circuit includes a diode, a ground capacitor, a comparator, a first AND logic gate, and a second AND logic gate.

6. The aforementioned discharge bridge drive circuit is used to generate drive signal A and drive signal B. The drive signal A is used to drive K1 and K4, and the drive signal B is used to drive K2 and K3. The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 5, characterized in that an on / off switch drive signal is generated by connecting the drive signal A and the drive signal B to the OR logic gate, and the on / off switch drive signal is used to drive the first on / off switch and the second on / off switch.

7. In the aforementioned on / off bridge drive circuit, The current sensor is connected to the anode of the diode, The same-direction input terminal of the comparator is connected to the cathode of the diode and grounded via the ground capacitor. The inverting input terminal of the comparator is connected to the current sensor. The output terminals of the comparator are connected to the first AND logic gate and the second AND logic gate, respectively. After the drive signal A and the output of the comparator are processed by the first AND logic gate, the output signal is used to drive S11, S14, S21, and S24. The electromagnetic exploration emission system for overcoming the effects of load inductance according to claim 6, characterized in that the drive signal B and the output of the comparator are processed by the second AND logic gate, and the output signal is used to drive S12, S13, S22, and S23.

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