Excitation device and method of open-loop transmitting coil system

Abstract

The invention belongs to the technical field of oil exploration and development, and discloses an excitation device and method for an open-loop transmitting coil system, and the device comprises a high-voltage transmission control unit which comprises an isolation gate driver and a full-bridge drive circuit. The isolated gate driver is used for inputting a control signal and converting the control signal into a high-low level signal; the full-bridge driving circuit is used for inputting a high-voltage excitation signal and converting the high-voltage excitation signal into a pulse power signal for exciting the open-loop transmitting coil system under the action of the high-low level signal; two bridge arms of the full-bridge driving circuit are respectively used for connecting two ends of an opening of the open-loop transmitting coil system, so that forward and reverse excitation can be realized along with conduction of different bridge arms. The device is suitable for underground narrow space, and has the advantages of high excitation efficiency, strong anti-interference capability and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil exploration and development, particularly to the technical field of boundary detection while drilling, and specifically relates to an excitation device and method for an open-loop transmitting coil array. Background Art

[0002] Existing boundary detection instruments while drilling include conventional electromagnetic logging while drilling instruments, azimuthal electromagnetic logging while drilling instruments, and ultra-deep azimuthal electromagnetic logging while drilling instruments. The essence of the circumferential boundary detection method lies in measuring the cross components of the magnetic field. The working frequency of conventional instruments ranges from 100 kHz to 2 MHz, and the source distance between the transmitting and receiving antennas is less than 3.5 m, without azimuth resolution ability and forward detection ability. The azimuthal electromagnetic logging while drilling instrument is based on an inclined coil array and adopts a multi-frequency and multi-source distance measurement method, having azimuth detection ability and the detection depth is extended to the formation interface within several meters around the wellbore, but only has limited forward detection ability. The ultra-deep azimuthal electromagnetic logging while drilling uses inclined antennas to measure the magnetic field tensor, the working frequency is reduced to the range of 1 - 100 kHz, the circumferential boundary detection ability is improved to the formation interface tens of meters outside the wellbore, and at the same time, the forward detection ability of the formation interface within the range of 5 - 30 m in front of the drill bit is also achieved. Although the problem of forward long-distance detection is solved to a certain extent, there are still many problems in the existing forward detection methods. First, the instrument source distance is too long, increasing the difficulty of synchronous signal measurement and reducing the vertical resolution of the instrument. Second, the instrument does not have azimuth recognition ability for the formation in front of the transmitting coil and the formation behind the receiving coil, and the contribution of the formation in front to the measurement signal is small, increasing the difficulty and uncertainty of interpretation. In short, the instrument response is complex and not intuitive, and information such as the formation interface in front of the drill bit needs to be obtained through inversion, and the inversion overly relies on prior information such as the resistivity and interface of the drilled formation, posing harsh requirements for on-site applications.

[0003] In order to solve the contradiction between the instrument source distance and the interface detection distance, a large amount of work has been done in the theory of electromagnetic far detection at home and abroad, and the transient electromagnetic far detection method and the electromagnetic short-source distance far detection method based on the electric field component have been proposed and developed. The core of the far detection method based on the electric field component is to design a combination of an open-loop magnetic dipole transmitting coil and an open-loop electric dipole receiving coil, that is, a hybrid dipole antenna. Compared with existing boundary detection instruments while drilling, the difficulty of the new technology lies in the lack of the best excitation means for the open-loop transmitting coil array suitable for the drilling environment. When the source distance between the hybrid dipole antennas is short, the influence of factors such as the wellbore and drill collars may increase. How to efficiently excite the transmitting coil to achieve the best detection effect is one of the key research directions in the future. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the above-mentioned prior art, and provide an excitation device and method for an open-loop transmitting coil array.

[0005] The present invention is implemented through the following technical solutions: An excitation device for an open-loop transmitting coil system, comprising a high-voltage transmitting control unit, and the high-voltage transmitting control unit includes an isolated gate driver and a full-bridge drive circuit; the isolated gate driver is used to input a control signal and convert the control signal into a high and low level signal; the full-bridge drive circuit is used to input a high-voltage excitation signal and convert the high-voltage excitation signal into a pulse power signal for exciting the open-loop transmitting coil system under the action of the high and low level signal; the two bridge arms of the full-bridge drive circuit are respectively used to connect the two ends of the opening of the open-loop transmitting coil system, so as to be able to achieve positive and negative excitation with the conduction of different bridge arms.

[0006] Further, each bridge arm of the full-bridge drive circuit includes a high-side power switch tube and a low-side power switch tube; the gate of the high-side power switch tube is used to input a high level, and the gate of the low-side power switch tube is used to input a low level; the output end of the high-side power switch tube and the input end of the low-side power switch tube are both used to connect to the same opening end of the open-loop transmitting coil system; the input end of the high-side power switch tube is used to input a high-voltage excitation signal; the output end of the low-side power switch tube is used to ground.

[0007] Further, each bridge arm of the full-bridge drive circuit is respectively connected to the opening end of the open-loop transmitting coil system through its own filter output unit.

[0008] Further, the filter output unit includes a filter and an output transformer.

[0009] Further, it further includes a logic control unit for generating a control signal; the logic control unit is used to input a clock signal and a synchronization signal, and divide the clock signal under the control of the synchronization signal to generate multiple control signals simultaneously.

[0010] Further, when there are n full-bridge drive circuits, the number of input ports and output ports of the logic control unit is at least 4n.

[0011] Further, the logic control unit inputs the clock signal and the synchronization signal through an optical isolation unit.

[0012] Further, it further includes an energy storage unit for generating a high-voltage excitation signal, and the energy storage unit includes a high-voltage power supply, a current-limiting resistor and an energy storage capacitor. The high-voltage power supply charges the energy storage capacitor through the current-limiting resistor, and the energy storage capacitor outputs high-voltage direct current as the high-voltage excitation signal.

[0013] Further, it further includes a power supply unit for supplying power to the logic control unit, the high-voltage transmitting control unit and the energy storage unit.

[0014] The present invention also provides a method for exciting an open-loop transmitting coil system, which uses the exciting device of the open-loop transmitting coil system of the present invention to excite the open-loop transmitting coil system in the hybrid dipole antenna.

[0015] Further, the hybrid dipole antenna is a short source distance antenna and is installed on the surface of the drill collar, and the exciting device of the open-loop transmitting coil system is installed in the groove of the drill collar.

[0016] Compared with the prior art, the beneficial effects of the present invention include:

[0017] 1. The present invention realizes positive and negative excitation, that is, it can excite the open-loop transmitting coil system to form a clockwise or counterclockwise flowing current, and can be positively or negatively excited according to needs, and can also be positively and negatively alternately excited to reach the best working state. The two open ends of the open-loop transmitting coil system can be used as either input or output. When an excitation signal is input at one end, the other end is used as output to form a current loop.

[0018] 2. The logic control unit divides the frequency to generate multiple control signals simultaneously. The pulse power signal generated by the full-bridge drive circuit contains multiple frequency components, realizing multi-frequency simultaneous excitation, and can realize interface detection with different detection depths and different resolutions.

[0019] 3. The circuit structure of the exciting device of the present invention is simple and the volume is small, and it can be installed in a narrow space, that is, the groove of the drill collar, so it is suitable for downhole narrow space operations.

[0020] 4. The optical isolation unit prevents the high-voltage pulse excitation signal from generating noise interference to the digital signal, ensuring that the logic control unit can generate high-precision control signals.

[0021] 5. Each bridge arm of the full-bridge drive circuit is respectively connected to the open end of the open-loop transmitting coil system through its own filtering output unit, avoiding invalid frequencies and noise interference.

[0022] 6. The full-bridge drive circuit has the characteristics of fast conduction and turn-off, that is, the power switch tube can conduct or cut off in the nanosecond level, so the rising and falling edges of the generated pulse power signal can be very steep, which is beneficial to improving the excitation efficiency of the transmitting coil system. The excitation efficiency is defined as the ratio of the AC voltage or current of the transmitting coil system to the amplitude of the pulse power signal. Therefore, when the rising and falling edges are both relatively steep, the excitation efficiency is much larger than that when the rising and falling edges change slowly.

[0023] 7. The present invention overcomes the deficiencies in the prior art such as the lack of the best excitation means for the open-loop transmitting coil system suitable for the drilling environment, realizes problems such as the high-efficiency multi-frequency excitation of the transmitting coil system, the rapid electromagnetic signal commutation, and the noise interference, and improves the ability of the open-loop transmitting coil system for high-efficiency multi-frequency excitation. Description of the Drawings

[0024] Figure 1 It is a schematic structural diagram of an excitation device for an open-loop transmitting coil system of the present invention.

[0025] Figure 2 It is a schematic structural diagram of an open-loop transmitting coil system of the present invention.

[0026] Figure 3 It is a flowchart of a method for exciting an open-loop transmitting coil system of the present invention. Detailed implementation manners

[0027] In order to overcome the lack of an optimal excitation means for an open-loop transmitting coil system applicable to a drilling environment in the prior art, an excitation device and method for an open-loop transmitting coil system are provided to realize the excitation of multi-frequency electromagnetic signals for the transmitting coil system in a narrow space.

[0028] The open-loop transmitting coil system is composed of a plurality of coil windings with an open-loop structure on the surface of a drill collar.

[0029] The excitation device for the open-loop transmitting coil system includes: an optical isolation unit, a logic control unit, a high-voltage emission control unit, a power supply unit, an energy storage unit, and a filtering output unit.

[0030] The optical isolation unit consists of a clock signal, a synchronization signal, and an optical isolator. Both the clock signal and the synchronization signal enter the logic control unit after being output by the optical isolator to generate a highly reliable and high-precision control signal, while preventing the high-voltage pulse excitation signal from generating noise interference to digital signals. The digital signals include the clock signal, the synchronization signal, and the control signal.

[0031] The logic control unit, under the control of the synchronization signal, performs frequency division processing on the clock signal to generate a control signal. The control signal is a square wave signal with a certain amplitude and period.

[0032] The logic control unit takes an FPGA (Field-programmable Gate Array) device as the control core and consists of a control circuit, a storage circuit, a download circuit, and a reset circuit. The logic control unit is connected to the optical isolation unit and generates multiple-channel logic signals for controlling the high-voltage emission control unit to realize the forward or reverse excitation of multiple transmitting coil systems.

[0033] The high-voltage emission control unit includes at least 4 power switch tubes. High and low level signals need to be applied to each power switch tube to control its conduction and cut-off, so multiple-channel logic signals need to be generated.

[0034] When there are n full-bridge drive circuits, the number of input ports and output ports of the logic control unit is at least 4n.

[0035] The high-voltage emission control unit consists of an isolated gate driver and a high-low side power switch tube array. The isolated gate driver realizes level conversion and the conduction and cutoff of the high-low side power switch tube array. The high-voltage emission control unit is respectively connected to the logic control unit and the energy storage unit, and is used to, under the trigger of the logic control unit, forwardly or reversely excite the emission coil system by controlling the loading of the high-voltage excitation signal output by the energy storage unit. The high-voltage excitation signal output by the energy storage unit belongs to a high-voltage DC voltage within the discharge period, and a high-voltage pulse excitation signal can be generated as long as the conduction and cutoff of the power switch tubes are controlled within the discharge period.

[0036] The isolated gate driver has at least two input terminals, namely the high-side control input terminal and the low-side control input terminal, and the input terminals are both connected to the logic control unit; the isolated gate driver also has at least two output terminals, namely the high-side floating ground drive output terminal and the low-side drive output terminal, and the output terminals are respectively connected to the bridge high-side and low-side power switch tube arrays. The input terminal of the high-side power switch tube is connected to the output terminal of the energy storage unit, the output terminal of the high-side power switch tube and the input terminal of the low-side power switch tube are both connected to the input terminal of the emission coil system, and the output terminal of the low-side power switch tube is grounded. The isolated gate driver and the high-low side power switch tube array form a full-bridge drive circuit. The pulse power signal generated by the power switch tube array contains multiple frequency components, realizing simultaneous excitation of multiple frequencies, and can realize interface detection with different detection depths and different resolutions.

[0037] The full-bridge drive circuit is to convert the DC voltage into a high-voltage pulse signal by controlling the conduction and cutoff of multiple power switch tubes.

[0038] The power supply unit consists of a lithium battery pack, a converter and a filter network. The power supply unit supplies power to the energy storage unit, the logic control unit and the high-voltage emission control unit respectively. The power supply circuit is also a noise circuit, so multiple-stage power filters are added to the power supply terminal to prevent it from causing crosstalk to the digital control logic signal and other external circuits.

[0039] The energy storage unit consists of a high-voltage power supply, a current-limiting resistor and an energy storage capacitor. The high voltage output by the high-voltage power supply is de-coupled and filtered, and then charges the energy storage capacitor through the current-limiting resistor. The energy storage capacitor discharges to provide a high-voltage excitation signal to the high-voltage emission control unit.

[0040] The filter output unit consists of a filter and an output transformer. The filter output unit is connected to the high-voltage emission control unit, and is used to filter out the useless harmonic components in the multiple frequency components generated by the power switch tube array to improve the signal-to-noise ratio of the emission signal. The filter output unit increases the emission power through the output transformer to directly drive the emission coil system to excite.

[0041] A method for exciting an open-loop transmitting coil system is provided. The exciting method is based on the exciting device of the open-loop transmitting coil system provided by the present invention and uses a full-bridge structure for excitation, realizing multi-frequency forward or reverse excitation and multi-channel combined excitation. The method for exciting an open-loop transmitting coil system includes:

[0042] Step 1: The logic control unit generates control logic signals through FPGA programming;

[0043] Step 2: The control logic signals control the high-side floating ground driving end and the low-side driving end of the isolation gate driver to output high and low level signals;

[0044] Step 3: The output high and low level signals control the conduction and cut-off of the high-side and low-side power switch tube arrays, generating a pulse power signal containing multiple frequency components;

[0045] Step 4: The pulse power signal is loaded onto the filter output unit to directly drive the transmitting coil system for forward or reverse excitation and multi-channel combined excitation.

[0046] An exciting device and method for an open-loop transmitting coil system provided by the present invention realize precise control of the excitation pulse width and timing of the open-loop transmitting coil system under narrow space conditions by means of devices such as isolation drivers and power switch tubes. Moreover, under the control of the logic control unit, the rising and falling edges of the pulse power signal generated by the full-bridge structure excitation method can be very steep, which is beneficial to improving the excitation efficiency of the transmitting coil system and realizing multi-frequency forward or reverse excitation and multi-channel combined excitation.

[0047] The excitation efficiency is usually defined as the ratio of the AC voltage or current of the transmitting coil system to the amplitude of the pulse power signal. Through experimental tests, it is generally found that when the rising and falling edges are relatively steep, the excitation efficiency is much greater than that when the rising and falling edges change slowly.

[0048] Under the trigger of a high-precision logic control signal, the full-bridge drive circuit structure and the fast conduction and cut-off characteristics of the power switch tubes can generate steep rising and falling edges. The excitation pulse width needs to be greater than the conduction time and cut-off time of the power switch tubes. For the timing requirement, the logic control signals of the upper-side and lower-side power switch tubes in the same path are required to have opposite phases.

[0049] Embodiment 1

[0050] The present invention will be further described in detail below with reference to the accompanying drawings:

[0051] In order to overcome the deficiencies in the prior art such as the lack of the best excitation means for an open-loop transmitting coil system applicable to the drilling environment, the present invention provides an excitation device and method for an open-loop transmitting coil system, realizing the forward or reverse excitation of multi-frequency electromagnetic signals and multi-channel combined excitation of the transmitting coil system in a narrow space. On the one hand, the provided excitation device for the open-loop transmitting coil system uses devices such as an isolation driver and a power switch tube to achieve precise control of the excitation pulse width and timing of the open-loop transmitting coil system under the conditions of a narrow downhole space. On the other hand, the provided excitation device for the open-loop transmitting coil system uses a full-bridge structure excitation method to generate a pulse power signal with very steep rising and falling edges, which is beneficial to improving the excitation efficiency of the transmitting coil system and realizing multi-frequency forward or reverse excitation and multi-channel combined excitation.

[0052] As Figure 1 shown, the excitation device for the open-loop transmitting coil system provided by the present invention includes: an optical isolation unit 11, a logic control unit 12, a high-voltage emission control unit 13, a power supply unit 14, an energy storage unit 15, and a filtering output unit 16.

[0053] The optical isolation unit 11 consists of a clock signal, a synchronization signal, and an optical isolator. The optical isolator includes at least two channels, and their input ends are respectively connected to the clock signal and the synchronization signal. Both the clock signal and the synchronization signal enter the logic control unit 12 after being output by the optical isolator, generating a highly reliable and high-precision control signal, and at the same time preventing the high-voltage pulse excitation signal from generating noise interference to the digital signal.

[0054] The logic control unit 12 consists of a control circuit, a storage circuit, a download circuit, and a reset circuit. The control circuit uses an FPGA (Field-programmable Gate Array) device as the control core and generates multi-channel control timings through programming. The storage circuit stores the FPGA configuration file information through a non-volatile memory and reads it into the on-chip memory. The download circuit debugs and solidifies the program of the FPGA through a JTAG (Joint Test Action Group) interface. The reset circuit is to make the logic control unit 12 return to the initial state at the moment of power-on. The logic control unit 12 is connected to the optical isolation unit 11 and generates at least four control signals triggered by the high-voltage emission control unit 13 to achieve the forward or reverse excitation of multiple transmitting coil systems.

[0055] The high-voltage emission control unit 13 consists of an isolated gate driver and a high-low side power switch tube array. The isolated gate driver and the high-low side power switch tube array form a full-bridge drive circuit. The pulse power signal generated by the power switch tube array contains multiple frequency components, enabling simultaneous excitation of multiple frequencies. The high-voltage emission control unit 13 is respectively connected to the logic control unit 12 and the energy storage unit 15, and is used to, under the trigger of the logic control unit 12, forwardly or reversely excite the emission coil system by controlling the loading of the high-voltage excitation signal output by the energy storage unit 15.

[0056] Combined Figure 2 As shown, the isolated gate driver uses a high-voltage-resistant bridge drive chip Driver IC (Integrated Circuit) with a floating ground drive function. The high-low side power switch tube array is a full-bridge circuit composed of four VMOS (V-groove Metal-oxide Semiconductor) or IGBT (Insulated Gate Bipolar Transistor) devices Q1, Q2, Q3, and Q4 with relatively high breakdown voltages. The isolated gate driver Driver IC realizes level conversion and the conduction and cutoff of the high-low side power switch tube array Q1, Q2, Q3, and Q4. The isolated gate driver Driver IC has four input terminals, namely two high-side control input terminals Hin1, Hin2 and two low-side control input terminals Lin1, Lin2, and all four input terminals are connected to the logic control unit 12; the isolated gate driver also has four output terminals, namely the high-side floating ground drive output terminals Hout1, Hout2 and the low-side drive output terminals Lout1, Lout2, and the four output terminals are respectively connected to the high-side and low-side power switches Q1, Q2, Q3, and Q4. The input terminals of the high-side power switches Q1, Q3 are connected to the output terminal of the energy storage unit 15, the output terminals of the high-side power switches Q1, Q3 and the input terminals of the low-side power switches Q2, Q4 are all connected to the input terminal of the emission coil system, and the output terminals of the low-side power switches Q2, Q4 are grounded.

[0057] The power supply unit 14 consists of a lithium battery pack, a converter, and a filter network. The power supply unit supplies power to the logic control unit 12, the high-voltage emission control unit 13, and the energy storage unit 15 respectively. The power supply loop is also a noise loop, so a first-stage power filter is added to the power supply terminal of the logic control unit 12 and a second-stage filter is added to the power supply terminal of the high-voltage emission control unit 13 to prevent crosstalk to the digital control logic signal and other external circuits.

[0058] The energy storage unit 15 consists of a high-voltage power supply, a current-limiting resistor, and an energy storage capacitor. The high voltage output by the high-voltage power supply is decoupled and filtered, and then charges the energy storage capacitor through the current-limiting resistor. The energy storage capacitor discharges to provide a high-voltage excitation signal for the high-side power switching transistors Q1 and Q3 in the high-voltage emission control unit 13.

[0059] The filter output unit 16 consists of a filter and an output transformer. The filter output unit 16 is connected to the high-voltage emission control unit 13 and is used to filter out the useless harmonic components in the multiple frequency components generated by the power switching transistor array Q1, Q2, Q3, and Q4 to improve the signal-to-noise ratio of the emission signal. The filter output unit 16 increases the emission power through the output transformer and directly drives the excitation of the emission coil system.

[0060] Embodiment 2

[0061] This embodiment provides an excitation method for an open-loop emission coil system. The excitation method uses the excitation device for the open-loop emission coil system provided by the present invention to achieve multi-frequency forward or reverse excitation and multi-channel combined excitation. Refer to Figure 3 As shown, the excitation method for the open-loop emission coil system includes:

[0062] Step 21: The logic control unit 12 generates multiple control logic signals through field-programmable logic device programming;

[0063] Step 22: The control logic signals control the high-side floating ground drive terminal and the low-side drive terminal of the isolation gate driver to output high and low level signals;

[0064] Step 23: The output high and low level signals control the conduction and cutoff of the high and low side power switching transistor arrays Q1, Q2, Q3, and Q4 to generate a pulse power signal containing multiple frequency components;

[0065] Step 24: The pulse power signal is loaded onto the filter output unit 16 to directly drive the emission coil system for forward or reverse excitation and multi-channel combined excitation.

[0066] Combined with Figure 1 and Figure 2 , in an embodiment of the forward or reverse excitation of the present invention, it is stipulated that when the excitation current of the emission coil system flows clockwise, it is forward excitation, and vice versa, when the current flows counterclockwise, it is reverse excitation.

[0067] Assume that the low-side power switching transistors Q2 and Q4 are in a state of being connected to the emission coil system, while the high-side power switching transistors Q1 and Q3 are always in a disconnected state.

[0068] Forward excitation working process: (1) Before the trigger arrives, turn off the low-side power switch Q2. After a short delay, turn on the high-side power switch Q1 to output the rising edge of the pulse power signal. The rising edge of the pulse power signal generates a multi-frequency excitation signal after filtering and boosting. The multi-frequency excitation signal directly drives the transmitting coil to form a clockwise flowing current. (2) When the pulse width of the trigger is about to end, turn off the high-side power switch Q1 in advance. After a short delay, turn on the low-side power switch Q2 to output the falling edge of the pulse power signal. The falling edge of the pulse power signal also generates a multi-frequency excitation signal after filtering and boosting. The multi-frequency excitation signal directly drives the transmitting coil to still form a clockwise flowing current.

[0069] Reverse excitation process: (1) Before the trigger arrives, turn off the low-side power switch Q4. After a short delay, turn on the high-side power switch Q3 to output the rising edge of the pulse power signal. The rising edge of the pulse power signal generates a multi-frequency excitation signal after filtering and boosting. The multi-frequency excitation signal directly drives the transmitting coil to form a counterclockwise flowing current. (3) When the pulse width of the trigger is about to end, turn off the high-side power switch Q3 in advance. After a short delay, turn on the low-side power switch Q4 to output the falling edge of the pulse power signal. The falling edge of the pulse power signal also generates a multi-frequency excitation signal after filtering and boosting. The multi-frequency excitation signal directly drives the transmitting coil to still form a counterclockwise flowing current.

[0070] Both the pulse power signal and the multi-frequency excitation signal are analog signals. The two open ends of the open-loop transmitting coil system can be used as either inputs or outputs. When a multi-frequency excitation signal is input at one end, the other end serves as the output to form a current loop.

[0071] The above technical solutions are only specific embodiments of the present invention. For those skilled in the art, based on the disclosed principles of the present invention, it is easy to make various types of improvements or modifications, not limited to the technical solutions described in the above specific embodiments of the present invention. Therefore, the foregoing description is only preferred and does not have a restrictive meaning.

Claims

1. An excitation device for an open-loop transmitting coil system, characterized in that: It includes a high-voltage emission control unit, and the high-voltage emission control unit includes an isolated gate driver and a full-bridge drive circuit; the isolated gate driver is used to input a control signal and convert the control signal into a high and low level signal; the full-bridge drive circuit is used to input a high-voltage excitation signal and convert the high-voltage excitation signal into a pulse power signal for exciting an open-loop emission coil system under the action of the high and low level signal; the two bridge arms of the full-bridge drive circuit are respectively used to connect the two ends of the opening of the open-loop emission coil system, so as to realize positive and negative excitation with the conduction of different bridge arms.

2. The excitation device of the open-loop transmitting coil system according to claim 1, characterized in that: Each bridge arm of the full-bridge drive circuit includes a high-side power switch tube and a low-side power switch tube; the gate of the high-side power switch tube is used to input a high level, and the gate of the low-side power switch tube is used to input a low level; the output end of the high-side power switch tube and the input end of the low-side power switch tube are both used to connect to the same opening end of the open-loop emission coil system; the input end of the high-side power switch tube is used to input a high-voltage excitation signal; the output end of the low-side power switch tube is used to connect to the ground.

3. The excitation device for the open-loop transmitting coil system according to claim 1, characterized in that: Each bridge arm of the full-bridge drive circuit is respectively connected to the opening end of the open-loop emission coil system through its respective filter output unit.

4. The excitation device for the open-loop transmitting coil system according to claim 3, characterized in that: The filter output unit includes a filter and an output transformer.

5. The exciting device of the open-loop transmitting coil system according to claim 1, characterized in that: It further includes a logic control unit for generating a control signal; the logic control unit is used to input a clock signal and a synchronization signal, and divide the clock signal under the control of the synchronization signal to generate multiple control signals simultaneously.

6. The excitation device of the open-loop transmitting coil system according to claim 5, characterized in that: When there are n full-bridge drive circuits, the number of input ports and output ports of the logic control unit is at least 4n.

7. The excitation device for the open-loop transmitting coil system according to claim 6, characterized in that: The logic control unit inputs the clock signal and the synchronization signal through an optical isolation unit.

8. The excitation device for the open-loop transmitting coil system according to claim 1, characterized in that: It further includes an energy storage unit for generating a high-voltage excitation signal, and the energy storage unit includes a high-voltage power supply, a current-limiting resistor and an energy storage capacitor. The high-voltage power supply charges the energy storage capacitor through the current-limiting resistor, and the energy storage capacitor outputs high-voltage direct current as the high-voltage excitation signal.

9. The excitation device for the open-loop transmitting coil system according to claim 8, characterized in that: It further includes a power supply unit for supplying power to the logic control unit, the high-voltage emission control unit and the energy storage unit.

10. A method for exciting an open-loop transmitting coil system, characterized in that: An excitation device for an open-loop emission coil system as described in any one of claims 1 to 9 is used to excite the open-loop emission coil system in a hybrid dipole antenna.

11. The excitation method of the open-loop transmitting coil system according to claim 10, characterized in that: The hybrid dipole antenna is a short-spacing antenna and is installed on the surface of a drill collar, and the excitation device for the open-loop emission coil system is installed in a groove of the drill collar.

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