Airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system and its control method

Abstract

This disclosure provides an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system, including a power management unit for power supply; a full-bridge inverter circuit unit, including multiple parallel MOSFET full-bridge inverter modules, each MOSFET full-bridge inverter module emitting equal-amplitude in-phase bipolar parallel current pulses to its connected transmitting load, so that each transmitting load generates an equal-amplitude in-phase electromagnetic field, and the equal-amplitude in-phase electromagnetic fields are superimposed and act together on the target under test; an active adaptive adjustable voltage dual clamping unit, connected to the full-bridge inverter circuit unit, for clamping the rising and falling edges of each sub-pulse in the equal-amplitude in-phase bipolar parallel current pulse; a control unit for generating PWM timing logic control signals to control the full-bridge inverter circuit unit, so that each MOSFET full-bridge inverter module outputs an equal-amplitude in-phase bipolar parallel current pulse; and a detection unit for detecting the transmitting current, clamping current, and clamping voltage respectively, and feeding back the detection results to the control unit.

Description

Technical Field

[0001] This disclosure relates to the field of electromagnetic detection technology, and in particular to an airborne transient electromagnetic equal amplitude in phase parallel high-power transmitter system and its control method. Background Technology

[0002] Transient electromagnetic methods (AEM) are important geophysical exploration techniques. Especially compared to frequency-domain electromagnetic methods, time-domain electromagnetic methods, due to their fundamental advantages, enable long-distance detection with simpler equipment. Airborne transient electromagnetic methods (AEM) are widely used in engineering exploration, mineral exploration, and geological mapping due to their high efficiency, low cost, and good adaptability. An airborne transient electromagnetic detection system uses an aircraft as its carrier and mainly consists of an electromagnetic transmitter, a transmitting coil, and a receiving system. An alternating primary field is formed by a pulsed current in the transmitting coil; when the current is turned off, the primary field disappears rapidly, inducing eddy currents in underground conductors and exciting a time-varying alternating secondary field. The receiving system is responsible for capturing this information. Because the magnitude and attenuation rate of the induced eddy currents vary due to different underground physical characteristics, the secondary field can reflect the physical characteristics of the target. Analyzing the attenuation law of the secondary field helps identify the distribution and related physical parameters of underground geological bodies with different electrical properties. The current electromagnetic pulse transmitter is the core of the airborne electromagnetic system and directly affects the detection performance. This transmitter needs to achieve a current amplitude of several hundred to several thousand amperes and possess high-frequency pulse repetition characteristics. To meet these requirements, the rise and fall edges of the current pulse must be rapid and linear to reach a peak value in the kiloampere range within a short time. However, existing high-current electromagnetic pulse transmitting systems typically use a single transmitter paired with a multi-turn coil as the transmitting load, which can be equivalent to a circuit of a resistor and an inductor in series. Because inductors impede current changes, the rise and fall edges of the transmitter output current vary exponentially, making it impossible to quickly reach the peak current and turn off. Furthermore, the large voltage generated during turn-on and turn-off tests the withstand voltage performance of the components. Summary of the Invention

[0003] In view of this, in order to at least partially solve at least one of the aforementioned technical problems, this disclosure provides an airborne transient electromagnetic equal amplitude in phase parallel transmitter system and its control method.

[0004] To achieve the above objectives, the technical solution disclosed herein is as follows:

[0005] According to embodiments of this disclosure, an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system is provided, including a power management unit, a full-bridge inverter circuit unit, an active adaptive adjustable voltage dual clamping unit, a control unit, and a detection unit.

[0006] The power management unit is used for power supply; the full-bridge inverter circuit unit includes multiple parallel MOSFET full-bridge inverter modules. Each MOSFET full-bridge inverter module sends equal-amplitude, in-phase bipolar parallel current pulses to its connected transmitting load, so that each transmitting load generates an equal-amplitude, in-phase electromagnetic field. The equal-amplitude, in-phase electromagnetic fields are superimposed and act together on the target under test; the active adaptive adjustable voltage dual clamping unit is connected to the full-bridge inverter circuit unit and is used to clamp the rising and falling edges of each sub-pulse in the equal-amplitude, in-phase bipolar parallel current pulse; the control unit is used to generate PWM timing logic control signals to control the full-bridge inverter circuit unit, so that each MOSFET full-bridge inverter module outputs equal-amplitude, in-phase bipolar parallel current pulses; the detection unit is connected to the control unit, the full-bridge inverter circuit unit, and the active adaptive adjustable voltage dual clamping unit respectively, and is used to detect the transmitting current, clamping current, and clamping voltage respectively, and feed the detection results back to the control unit.

[0007] According to embodiments of this disclosure, the power management unit includes: a DC / DC main control circuit power supply module for supplying power to the control unit; a DC / DC power supply module for providing adjustable voltage to the full-bridge inverter circuit unit; and a DC / DC isolated drive circuit power supply module for providing the required voltage to the MOSFET driver.

[0008] According to embodiments of this disclosure, each of the MOSFET full-bridge inverter modules includes a first MOSFET power switch group and a second MOSFET power switch group. By controlling the first MOSFET power switch group and the second MOSFET power switch group to be turned on alternately, the current on the transmitting load can flow in the forward or reverse direction, thereby generating equal-amplitude, in-phase bipolar parallel current pulses.

[0009] According to embodiments of this disclosure, an active adaptive adjustable voltage dual-clamp module includes: an adjustable high-voltage power supply DC... H High-voltage capacitor bank, including multiple capacitors connected in parallel to an adjustable high-voltage DC power supply. H The high-voltage capacitors at both ends; power diode D13, connected in series with the adjustable high-voltage DC power supply. H On the output circuit, there are: a high-voltage capacitor bank with a voltage higher than the power supply voltage to prevent energy from flowing back into the power supply and causing damage; a high-voltage capacitor discharge resistor R3 connected in parallel across the high-voltage capacitor bank to discharge the energy stored in the high-voltage capacitor bank in time when the pulse current is emitted to avoid danger; and multiple clamping MOSFET power switches connected in series with each MOSFET full-bridge inverter module and then connected in parallel next to the high-voltage capacitor bank.

[0010] According to embodiments of this disclosure, an adjustable high-voltage DC power supply HConnected to the control unit, the control unit controls the adjustable high-voltage DC power supply according to the transmission load parameters and the combined pulse parameters. H The output voltage enables the adjustable high-voltage DC power supply. H The high-voltage capacitor is charged to a set constant voltage. Based on the combined pulse parameters to be transmitted, the control unit controls multiple clamping MOSFET power switches to precisely conduct for a set time on the rising edge of the equal-amplitude, in-phase bipolar parallel current pulse. This allows the high-voltage capacitor bank to release energy to the transmitting load through the MOSFET full-bridge inverter module on the rising edge of the current pulse, enabling rapid establishment of the current pulse. The combined pulse parameters include the frequency, amplitude, and width of the combined pulse.

[0011] According to embodiments of this disclosure, the high-voltage capacitor bank absorbs the voltage spike generated by the transmitting load at the moment of turn-off, causing the current pulse to decrease rapidly and linearly.

[0012] According to embodiments of this disclosure, multiple clamped MOSFET power switches, in conjunction with a high-voltage capacitor bank, achieve dual clamping of the pulse adjustable voltage and adjustable intervention time, thereby improving the quality of the transmitted waveform.

[0013] According to an embodiment of this disclosure, the control unit includes: an adaptive adjustable voltage control module, which calculates and outputs a clamping voltage and clamping time based on the real-time detection results collected by the detection unit, thereby clamping the rising and falling edges of the current pulse.

[0014] Another embodiment of this disclosure provides a control method for the above-described airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system, comprising: charging a high-voltage capacitor bank and providing the same voltage to multiple MOSFET full-bridge inverter modules; the multiple MOSFET full-bridge inverter modules, under the action of the supply voltage, emitting equal-amplitude in-phase bipolar parallel current pulses to connected transmitting loads, so that the superimposed electromagnetic field generated by the multiple parallel transmitting loads acts on the target under test; performing active adaptive adjustable dual clamping on the rising and falling edges of each sub-pulse in the equal-amplitude in-phase bipolar parallel current pulse; detecting the equal-amplitude in-phase bipolar parallel current pulse, the supply voltage, the clamping current, and the clamping voltage; and issuing different PWM timing logic control signals based on the detection results to adjust the equal-amplitude in-phase bipolar current pulse.

[0015] This disclosure presents an airborne transient electromagnetic equal-amplitude, in-phase parallel transmitter system and its control method. Multiple low-power transmitters with equal amplitude and in-phase power are connected to multiple single-turn loads in parallel within an active adaptive adjustable voltage dual constant-voltage clamping circuit. This alleviates technical problems such as high instantaneous power demand when a single transmitter emits a large current pulse, large transmitting inductance of a single transmitting coil, high instantaneous voltage during turn-on and turn-off posing challenges to component withstand voltage, and insufficient speed and linearity of current rise and fall edges. The active adaptive adjustable voltage dual clamping technology used in the transmitter system not only effectively clamps the high voltage of the current pulse fall edge at the moment the transmitting power switch is turned off, but also reverse-conducts the clamping power switch at the moment the transmitting power switch is turned on, allowing the high-voltage capacitor bank to charge the load in reverse. By controlling the turn-on time, it achieves the discharge of capacitor energy and helps to rapidly increase the current rise edge. Using multiple low-power transmitters with multiple single-turn loads results in a smaller size and weight compared to using a single high-power transmitter with a single multi-turn coil. Furthermore, the number of transmitters and loads in the parallel transmission system can be adjusted according to actual transmission requirements, making it more convenient for practical applications. Attached Figure Description

[0016] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0017] Figure 1 This is a schematic diagram of an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system according to an embodiment of the present disclosure.

[0018] Figure 2 This is a schematic diagram of an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system according to another embodiment of the present disclosure.

[0019] Figure 3 This is a flowchart of a control method for an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system according to an embodiment of this disclosure.

[0020] Figure 4 This is a schematic diagram of the on / off control and key waveforms of an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system according to an embodiment of this disclosure. Detailed Implementation

[0021] This disclosure provides an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system and its control method. Multiple low-power transmitters with equal amplitude and in-phase characteristics are each connected to a single-turn load and connected in parallel within an active adaptive adjustable voltage dual constant-voltage clamping circuit, forming a parallel high-power transmitter system. This alleviates technical problems such as the high instantaneous power demand of a single transmitter, the large transmitting inductance of the original single multi-turn transmitting coil, the high instantaneous voltage during turn-on and turn-off which puts pressure on the voltage withstand capability of components, and the insufficient speed and linearity of the current rise and fall edges. Simultaneously, the active adaptive adjustable voltage dual clamping technology used in this system not only effectively clamps the high voltage of the current pulse falling edge at the moment the transmitter circuit power switch is turned off, but also reverse conducts at the moment the transmitter circuit power switch is closed, allowing the high-voltage clamping capacitor to charge the load in reverse. By controlling the turn-on time, it achieves the functions of discharging capacitor energy and helping to rapidly increase the current rise edge.

[0022] This disclosure discloses an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system and its control method. Addressing the requirements of airborne time-domain electromagnetic detection pulses, it proposes using multiple low-power transmitters of equal amplitude and in-phase to connect a single-turn load, connected in parallel within a power-fed active constant-voltage clamping circuit. This forms a parallel high-power transmission system, alleviating the technical challenges of traditional transmission systems, such as high instantaneous power requirements of a single transmitter, large transmitting inductance of a single transmitting coil, high instantaneous voltage during turn-on and turn-off posing challenges to component withstand voltage, and rapid and linear current rise and fall times. It achieves high-quality pulse transmission with rapid establishment and rapid linear fall. Furthermore, unlike traditional active constant-voltage clamping technology, this system utilizes active adaptive adjustable voltage dual-clamping technology. This not only effectively clamps the current pulse at the moment the power switch of the transmitting circuit is turned off, but also reverse conducts at the moment the power switch of the transmitting circuit is closed, allowing the power-fed capacitor of the constant-voltage clamping circuit to charge the load in reverse. By controlling the turn-on time, it achieves energy dissipation from the capacitor and helps to rapidly increase the current rise time. In implementing this disclosure, it is necessary to: (1) design an active adaptive adjustable dual clamping module to actively clamp the rising and falling edges of the current in the equal-amplitude and in-phase parallel full-bridge inverter circuit; (2) require the active adaptive adjustable dual clamping module to accurately control the clamping voltage and clamping intervention time at the rising edge of each pulse for different amplitude pulses in the equal-amplitude and in-phase parallel full-bridge inverter circuit; (3) require precise control of the drive fast turn-off MOSFET to achieve stable output of the power inverter bridge; (4) accurately control the drive to achieve multiple emitter currents to achieve equal-amplitude and in-phase output of the parallel full-bridge inverter circuit; (5) accurately detect and feedback the real-time waveform of the emitter current; (6) accurately detect and feedback the clamping current and clamping voltage; (7) adaptively control and adjust the magnitude of the clamping voltage and intervention time according to the feedback emitter current and clamping current waveforms. To address the aforementioned issues, the purpose of this disclosure is to design a current pulse transmitter that can transmit current pulses using a parallel full-bridge inverter circuit with equal amplitude and in-phase connection, and to perform active adaptive adjustable dual clamping on both the rising and falling edges of the current pulse. Compared to traditional transmitter systems, this design has lower requirements for components, lower losses, and is more efficient.

[0023] To make the objectives, technical solutions, and advantages of this disclosure clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0024] In this embodiment of the disclosure, an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system is provided, combined with Figure 1 and Figure 2 As shown, the transmitter system includes:

[0025] The power management unit is used for power supply;

[0026] The full-bridge inverter circuit unit includes one or more MOSFET full-bridge inverter modules connected in parallel. Each MOSFET full-bridge inverter module sends equal-amplitude, in-phase bipolar parallel current pulses to its connected transmitting load, so that each transmitting load generates an equal-amplitude, in-phase electromagnetic field. The equal-amplitude, in-phase electromagnetic fields are superimposed and act together on the target under test.

[0027] An active adaptive adjustable voltage dual clamping unit, connected to the full-bridge inverter circuit unit, is used to clamp the rising and falling edges of each sub-pulse in the equal-amplitude in-phase bipolar parallel current pulse.

[0028] The control unit is used to generate PWM timing logic control signals to control the full-bridge inverter circuit unit, so that each MOSFET full-bridge inverter module outputs equal-amplitude, in-phase, bipolar parallel current pulses; and

[0029] The detection unit is connected to the control unit, the full-bridge inverter circuit unit, and the active adaptive adjustable voltage dual clamping unit, respectively, and is used to detect the emission current, clamping current, and clamping voltage, and to feed the detection results back to the control unit.

[0030] According to an embodiment of this disclosure, the power management unit includes:

[0031] The DC / DC main control circuit power module supplies power to the control unit.

[0032] DC / DC power supply modules are used to provide adjustable voltage to the full-bridge inverter circuit unit; and

[0033] A DC / DC isolated drive circuit power supply module is used to provide the required voltage to the MOSFET driver that drives the active adaptive adjustable voltage dual clamp unit.

[0034] According to embodiments of this disclosure, such as Figure 1 As shown, the full-bridge inverter circuit unit includes a MOSFET full-bridge inverter module connected to a transmitter load, such as... Figure 2 The full-bridge inverter circuit unit shown includes two parallel-connected MOSFET full-bridge inverter modules. Each MOSFET full-bridge inverter module includes a first MOSFET power switch group and a second MOSFET power switch group. By controlling the first MOSFET power switch group and the second MOSFET power switch group to alternately conduct, the current direction on the transmitting load can be made to flow in the forward or reverse direction, thereby generating equal-amplitude, in-phase, bipolar parallel current pulses. Specifically, as shown... Figure 1As shown, in the MOSFET full-bridge inverter module, MOSFET power switch Q1 and MOSFET power switch Q3 constitute the first MOSFET power switch group, and MOSFET power switch Q2 and MOSFET power switch Q4 constitute the second MOSFET power switch group.

[0035] like Figure 2 As shown, in the MOSFET full-bridge inverter module (which can be referred to as the first MOSFET full-bridge inverter module) located at the bottom of the diagram, MOSFET power switches Q1 and Q4 constitute the first MOSFET power switch group, and MOSFET power switches Q2 and Q3 constitute the second MOSFET power switch group. The control unit can alternately control the first MOSFET power switch group or the second MOSFET power switch group to conduct, allowing the current on the transmitting load (equivalent to RL1, L1, R1 in the diagram) to flow in the forward and reverse directions, thereby generating bipolar parallel current pulses.

[0036] like Figure 2 As shown, in the MOSFET full-bridge inverter module (which can be called the second MOSFET full-bridge inverter module) located at the top of the diagram, MOSFET power switches Q5 and Q8 constitute the first MOSFET power switch group, and MOSFET power switches Q6 and Q7 constitute the second MOSFET power switch group. The control unit can alternately control the first or second MOSFET power switch group to conduct, allowing the current to flow in the forward and reverse directions on another transmitting load (equivalent to RL2, L2, R2 in the diagram), thereby generating bipolar parallel current pulses.

[0037] Each MOSFET power switch contains a body diode. D1-D8 represent the body diodes inside the eight MOSFETs, and are not discrete components. When the first or second MOSFET power switch group is turned on, the body diodes D1-D8 are all in reverse cutoff. When the first or second MOSFET power switch group is turned off, since the transmitting load is inductive and the current cannot change abruptly, the body diodes D1-D8 are briefly turned on to quickly release the energy on the transmitting load.

[0038] According to embodiments of this disclosure, in conjunction with Figure 1 and Figure 2 As shown, the active adaptive adjustable voltage dual-clamp unit includes an adaptive clamping circuit and an adaptive clamping high-voltage source: specifically, it includes:

[0039] Variable voltage high voltage power supply DC H ;

[0040] High-voltage capacitor bank, comprising multiple capacitors connected in parallel to an adjustable high-voltage DC power supply. H High-voltage capacitors (C1-Cn) at both ends;

[0041] Power diode D13 is connected in series with the adjustable high voltage power supply DC. H On the output circuit, it is used to prevent energy from flowing back into the power supply and causing damage when the voltage of the high-voltage capacitor bank is higher than the power supply voltage;

[0042] The high-voltage capacitor discharge resistor R3 is connected in parallel across the high-voltage capacitor bank to promptly discharge the energy stored in the high-voltage capacitor bank at the end of the pulse current emission, preventing any potential danger; and

[0043] Multiple clamped MOSFET power switches are connected in series with each MOSFET full-bridge inverter module and then in parallel with the high-voltage capacitor bank.

[0044] According to embodiments of this disclosure, the high-voltage capacitor bank absorbs the voltage spike generated by the transmitting load at the moment of turn-off, causing the current pulse to decrease rapidly and linearly. Multiple clamped MOSFET power switches, in conjunction with the high-voltage capacitor bank, achieve dual clamping of the pulse with adjustable voltage and adjustable intervention time, thereby improving the quality of the transmitted waveform.

[0045] like Figure 1 The diagram may also include a MOSFET power switch Q5, such as... Figure 2 As shown, it includes two MOSFET power switches, Q9 and Q10, which are connected after the first MOSFET full-bridge inverter module and the second MOSFET full-bridge inverter module, respectively. Adjustable high-voltage DC power supply. H One end is connected to the control module, which controls the adjustable high-voltage DC power supply according to the transmission load parameters and combined pulse parameters. H The output voltage of the adjustable high-voltage DC power supply. HThe high-voltage capacitors are charged to a constant voltage. Based on the parameters of the combined pulse to be transmitted (including the frequency, amplitude, and width of the combined pulses), the control module controls Q9 and Q10 to precisely conduct for a period of time on the rising edge of the bipolar combined current pulse. This allows the high-voltage capacitor bank C1-Cn to release energy to the transmitting load through the MOSFET equal-amplitude, in-phase, parallel full-bridge inverter module on the rising edge of the current pulse, enabling rapid current pulse establishment. The high-voltage capacitor bank C1-Cn absorbs the voltage spike generated by the transmitting load at the moment of turn-off, causing the current pulse to decrease rapidly and linearly. Q9, Q10, and C1-Cn work together to achieve dual clamping of adjustable pulse voltage and adjustable intervention time, significantly improving the quality of the transmitted waveform. D13 prevents energy from flowing back into the power supply and causing damage when the voltage of capacitor bank C1-Cn exceeds the power supply UC voltage. The high-voltage capacitor bleed resistor R3 releases the energy stored in the high-voltage capacitor bank C1-Cn in a timely manner at the end of transmission, avoiding any danger.

[0046] According to embodiments of this disclosure, in conjunction with Figure 1 , Figure 2 As shown, the detection unit includes: a transmission current detection module, a clamping current detection module, and a clamping voltage detection module.

[0047] A current detection module is connected to the transmitting load and is used to detect bipolar combined current pulses in the transmitting load. A clamping voltage detection module is connected to the active adaptive adjustable voltage dual clamping module and is used to detect the voltage of the high-voltage capacitor bank. A clamping current detection module is connected to the active adaptive adjustable dual clamping module and is used to detect current pulses flowing into and out of the high-voltage capacitor bank. The current detection module includes a Hall current sensor, an operational amplifier, and a differential amplifier. The current value collected by the sensor is processed and converted, and the signal is transmitted to the control module. The clamping voltage detection module includes a voltage divider chip, a voltage follower, and an isolator. The clamping voltage is divided by a power resistor, collected and converted by the voltage acquisition chip, and then transmitted to the control module via the voltage follower and isolator.

[0048] According to an embodiment of this disclosure, the control unit includes: an adaptive adjustable voltage clamping control module, a power supply voltage control module, and a MOSFET drive signal control module.

[0049] The adaptive adjustable voltage control module calculates and outputs the clamping voltage and clamping time based on the real-time detection results collected by the detection unit, thereby clamping the current pulse on both the rising and falling edges.

[0050] The adaptive adjustable voltage control module is connected to the detection unit and outputs different control quantities based on the detection results, including adaptive clamping voltage control and adaptive clamping time control. Its core is an adaptive controller, which is based on a model adaptive control method. It calculates and outputs the clamping voltage and clamping time based on real-time data collected by the current detection module, clamping voltage detection module, and clamping current detection module, thereby achieving active adaptive adjustable dual clamping of the transmitting current.

[0051] The adaptive adjustable voltage control module is connected to the detection unit and outputs different control quantities based on the detection results, including adaptive clamping voltage control and adaptive clamping time control. The adaptive adjustable clamping voltage control module, based on the output of the adaptive control module, acts on the adjustable high-voltage DC power supply. H The clamping voltage is adjusted; the adaptive clamping time control module acts on MOSFETs Q9 and Q10 based on the control quantity output by the adaptive control module to adjust the clamping intervention time.

[0052] The power supply voltage control module acts on the DC / DC power supply modules of each parallel full-bridge inverter circuit based on the control quantity output by the main control module, so as to ensure that the same power supply voltage is provided to each full-bridge inverter circuit.

[0053] The MOSFET drive signal control module generates PWM timing logic control signals with different duty cycles using an FPGA.

[0054] The control unit may also include:

[0055] The FPGA controller is used to generate PWM timing logic control signals, full-bridge inverter circuit power supply voltage regulation, adaptive clamping voltage regulation and clamping time control signals, and to control and receive GPS module signals and communicate with the MCU controller.

[0056] The MCU controller is used to control the human-machine interaction display touch screen and indicator lights, as well as write data to the SD card. It also issues transmission parameters and instructions to the FPGA controller and is responsible for receiving temperature sensor data.

[0057] The GPS module is used to determine the transmitter's location in real time;

[0058] An SD card storage module is used to store current waveform data and GPS information;

[0059] The temperature detection module monitors the internal temperature of the transmitter in real time to prevent the system from overheating;

[0060] The MOSFET drive module is connected to the control module, converts the control signal into a MOSFET power switch control signal with stronger driving capability, and realizes electrical isolation between the control module and the power switch in the MOSFET full-bridge inverter circuit.

[0061] The human-computer interaction display touch screen is used to display the launch parameters in real time, as well as to allow users to set the launch parameters and control the launch.

[0062] In another aspect, this disclosure also provides a control method for the above-described airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system, such as... Figure 3 As shown, the control method includes:

[0063] Operation S1: Charge the high-voltage capacitor bank and provide the same voltage to multiple MOSFET full-bridge inverter modules;

[0064] Operation S2: Under the influence of the supply voltage, multiple MOSFET full-bridge inverter modules emit equal-amplitude, in-phase bipolar parallel current pulses to the connected transmitting loads, so that the superimposed electromagnetic field generated by the multiple parallel transmitting loads acts on the target under test.

[0065] Operation S3: Active adaptive adjustable dual clamping is performed on the rising and falling edges of each sub-pulse in the equal-amplitude, in-phase bipolar parallel current pulse.

[0066] Operation S4: Detects equal-amplitude, in-phase bipolar parallel current pulses, supply voltage, clamping current, and clamping voltage; and

[0067] Operation S5: Based on the detection results, different PWM timing logic control signals are issued to adjust the equal amplitude and in-phase bipolar current pulses.

[0068] Specifically, the high-voltage capacitor bank is first charged using an adjustable high-voltage power supply, and the same voltage is provided to each power supply module of the parallel full-bridge inverter circuit. Under the action of the power supply voltage of the power supply module, an equal-amplitude and in-phase current pulse is emitted to the connected transmitting load, so that the combined electromagnetic field generated by the parallel transmitting load acts on the target under test. The rising and falling edges of each sub-pulse in the bipolar parallel current pulse are actively adaptively adjustable dual-clamped. The bipolar parallel current pulse, the power supply voltage, and the clamping current and clamping voltage used for clamping are detected. Based on the detection results and human control, different timing logic control signals are issued to adjust the bipolar current pulse.

[0069] In this embodiment of the disclosure, combined with Figure 4 and Figure 1 , Figure 2As shown, S1 is the control signal for the first MOSFET power switch group, S2 is the control signal for the second MOSFET power switch group, and S3 is the control signal for clamping MOSFET power switch groups Q9 and Q10. 负载 (t) represents the current pulse, I （max） U is the maximum current of the full-bridge inverter circuit. 负载 (t) represents the voltage at the transmitting load, U （电源） The voltage supplied to the DC / DC power supply module, U （钳位） The clamping voltage, I 钳位 (t) represents the clamping current next to the high-voltage capacitor bank.

[0070] Before time t1, the launch preparation phase is underway. It is necessary to adjust the power supply voltage of the parallel full-bridge inverter circuit to the specified launch voltage in advance, adjust the adjustable high voltage power supply of the active adaptive adjustable voltage dual clamping module to the set clamping voltage, and charge the high voltage capacitor bank C1-Cn.

[0071] At time t1, the large forward current pulse in the equal-amplitude, in-phase bipolar parallel current pulse is transmitted. Signal S1 controls the first MOSFET power switch group to turn on, causing current to flow forward to the transmitting load, and the equal-amplitude, in-phase current in the parallel full-bridge inverter circuit begins to rise. Simultaneously, signal S3 controls the clamping MOSFET power switch group to turn on, enabling the active adaptive adjustable dual-clamp module to clamp the rising edge with high voltage. The high-voltage capacitor bank and the adjustable high-voltage power supply simultaneously supply power to the transmitting load, and the equal-amplitude, in-phase current rises rapidly and linearly. At this time, the current flowing through the clamping circuit is equal to the sum of the currents in the two full-bridge inverter circuits minus 2I. 发射 .

[0072] At time t2, signal S3 controls the clamping MOSFET power switch group to turn off, ending the rising edge clamping. The equal-amplitude in-phase current begins to rise exponentially to the peak value of the positive large current pulse I. （max） .

[0073] At time t3, signal S1 controls the first MOSFET power switch group to turn off, stopping the transmission of the forward high-current pulse. Simultaneously, the second MOSFET power switch group and the clamping MOSFET power switch group are turned on by the body diode. The active adaptive adjustable voltage dual-clamp module performs constant voltage clamping on the falling edge. The equal-amplitude, in-phase current on the transmitting load is transmitted through the... Figure 2 The body diodes D2, D3, D6, D7, D9, and D10 in the circuit flow to the high-voltage capacitor bank C1-Cn. C1-Cn absorbs excess energy from the emitting load, and the equal-amplitude, in-phase current decreases rapidly and linearly. Due to the parallel connection, the current flowing through the clamping circuit is the sum of the currents of the two full-bridge inverter circuits, 2I. （max） .

[0074] At time t4, the current drops to 0, and the clamping current also drops to 0. Body diodes D2, D3, D6, D7, D9, and D10 are turned off, and the forward, equal-amplitude, in-phase large current pulse is emitted.

[0075] During the time intervals t5 to t8, the large reverse current pulse emitted in the equal-amplitude, in-phase bipolar parallel current pulse has a clamping MOSFET power switch group control process that is similar to that during the time intervals t1 to t4. The only difference is that the on / off control of the first MOSFET power switch group in the MOSFET parallel full-bridge inverter circuit is replaced by the on / off control of the second MOSFET power switch group, which will not be elaborated further.

[0076] When the next cycle of equal-amplitude and in-phase positive and negative pulses arrives, the state t1-t8 repeats.

[0077] It should be noted that the MOSFET power switches in the full-bridge inverter circuit unit and the active adaptive adjustable voltage dual clamping unit can be replaced by IGBT power switches; small variations in the values ​​of components such as resistors and capacitors can also be made to obtain the current pulse and voltage values ​​required for the current scenario.

[0078] In summary, this disclosure provides an airborne transient electromagnetic equal-amplitude in-phase parallel high-power transmission system and control method to improve the problems of high resistance and inductance, resulting in poor detection effect and low efficiency, caused by a single transmitter paired with a multi-turn transmission coil in the existing airborne small electromagnetic transmission system; it achieves rapid establishment of the rising edge of the transmission current and rapid linear descent of the falling edge, improving the problem that traditional constant voltage clamping circuits cannot simultaneously clamp the rising and falling edges of current pulses with different widths and amplitudes, or have poor clamping effect.

[0079] The embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. It should be noted that implementations not illustrated or described in the drawings or the main text of the specification are forms known to those skilled in the art and are not described in detail. Furthermore, the definitions of the various elements and methods described above are not limited to the specific structures, shapes, or methods mentioned in the embodiments, and those skilled in the art can easily modify or substitute them.

[0080] It should be noted that, unless otherwise specified herein, having "a" element is not limited to having a single element, but may include one or more of the element.

[0081] Furthermore, unless otherwise specified, the ordinal numbers such as "first," "second," etc., used herein are merely for distinguishing multiple elements with the same name and do not indicate any hierarchy, order of execution, or process sequence among them. A "first" element and a "second" element may appear together in the same component or separately in different components. The presence of an element with a higher ordinal number does not necessarily indicate the presence of another element with a lower ordinal number.

[0082] In this document, unless otherwise specified, the term "characteristic A" or "and / or" and "characteristic B" means that A exists alone, B exists alone, or A and B exist simultaneously; the term "characteristic A" and "and" or "and" and "and" and "characteristic B" means that A and B exist simultaneously; the terms "including", "containing", "having", and "containing" refer to, but are not limited to, these.

[0083] Furthermore, in this document, terms such as "up," "down," "left," "right," "front," "back," or "between" are used only to describe the relative positions of multiple elements and can be extended to include translation, rotation, or mirroring. Additionally, unless otherwise specified, the statement "one element is on another element" or similar statements do not necessarily indicate that the element is in contact with the other element.

[0084] Furthermore, unless specifically described or required to occur in a specific order, the order of the above steps is not limited to those listed above and can be varied or rearranged according to the desired design. Moreover, the above embodiments can be used in combination with each other or with other embodiments based on design and reliability considerations; that is, technical features from different embodiments can be freely combined to form more embodiments.

[0085] The specific embodiments described above further illustrate the purpose, technical solutions, and beneficial effects of this disclosure. It should be understood that the above descriptions are merely specific embodiments of this disclosure and are not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. An airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system, comprising: The power management unit is used for power supply; The full-bridge inverter circuit unit includes multiple parallel MOSFET full-bridge inverter modules. Each MOSFET full-bridge inverter module sends equal-amplitude, in-phase bipolar parallel current pulses to its connected transmitting load, so that each transmitting load generates an equal-amplitude, in-phase electromagnetic field. The equal-amplitude, in-phase electromagnetic fields are superimposed and act together on the target under test. An active adaptive adjustable voltage dual clamping unit, connected to the full-bridge inverter circuit unit, is used to clamp the rising and falling edges of each sub-pulse in the equal-amplitude in-phase bipolar parallel current pulse. The control unit is used to generate PWM timing logic control signals to control the full-bridge inverter circuit unit, so that each MOSFET full-bridge inverter module outputs equal-amplitude, in-phase bipolar parallel current pulses; as well as The detection unit is connected to the control unit, the full-bridge inverter circuit unit, and the active adaptive adjustable voltage dual clamping unit, respectively, and is used to detect the emission current, clamping current, and clamping voltage, and to feed the detection results back to the control unit. Each of the MOSFET full-bridge inverter modules includes a first MOSFET power switch group and a second MOSFET power switch group. By controlling the first MOSFET power switch group and the second MOSFET power switch group to conduct alternately, the current on the transmitting load can flow in either the forward or reverse direction, thereby generating equal-amplitude, in-phase, bipolar parallel current pulses. The active adaptive adjustable voltage dual-clamping module includes: an adjustable high-voltage DC power supply. H High-voltage capacitor bank, including multiple capacitors connected in parallel to an adjustable high-voltage DC power supply. H The high-voltage capacitors at both ends; power diode D13, connected in series with the adjustable high-voltage DC power supply. H On the output circuit, there are: a high voltage capacitor bank voltage higher than the power supply voltage, which prevents energy from flowing back into the power supply and causing damage; a high voltage capacitor discharge resistor R3, which is connected in parallel across the high voltage capacitor bank, is used to discharge the energy stored in the high voltage capacitor bank in time when the pulse current is emitted to avoid danger; and multiple clamping MOSFET power switches, which are connected in series with each MOSFET full-bridge inverter module and then in parallel with the high voltage capacitor bank. The adjustable high voltage power supply DC H Connected to the control unit, the control unit controls the adjustable high-voltage DC power supply according to the transmission load parameters and the combined pulse parameters. H The output voltage enables the adjustable high-voltage DC power supply. H The high-voltage capacitor is charged to a set constant voltage. The control unit controls multiple clamping MOSFET power switches to precisely conduct for a set time on the rising edge of the equal-amplitude, in-phase bipolar parallel current pulse according to the combined pulse parameters to be transmitted. This allows the high-voltage capacitor bank to release energy to the transmitting load through the MOSFET full-bridge inverter module on the rising edge of the current pulse, enabling the current pulse to be established quickly. The multiple clamping MOSFET power switches, in conjunction with the high-voltage capacitor bank, achieve dual clamping of the pulse with adjustable voltage and adjustable intervention time, thereby improving the quality of the transmitted waveform. The control unit includes an adaptive adjustable voltage control module, which calculates and outputs the clamping voltage and clamping time based on the real-time detection results collected by the detection unit, thereby clamping the current pulse at the rising and falling edges.

2. The transmitter system according to claim 1, wherein the power management unit comprises: The DC / DC main control circuit power module supplies power to the control unit. DC / DC power supply module, used to provide adjustable voltage for full-bridge inverter circuit unit; as well as DC / DC isolated drive circuit power supply module, used to provide the required voltage to MOSFET driver.

3. In the transmitter system according to claim 1, the high-voltage capacitor bank absorbs the voltage spike generated by the transmitting load at the moment of shutdown, causing the current pulse to decrease rapidly and linearly.

4. The transmitter system according to claim 1, wherein the combined pulse parameters include the frequency, amplitude, and width of the combined pulse.

5. A control method for an airborne transient electromagnetic equal-amplitude in-phase parallel transmitter system according to any one of claims 1-4, comprising: The high-voltage capacitor bank is charged, and the same voltage is supplied to multiple MOSFET full-bridge inverter modules; Multiple MOSFET full-bridge inverter modules, under the influence of the supply voltage, emit equal-amplitude, in-phase bipolar parallel current pulses to the connected transmitting loads, so that the superimposed electromagnetic field generated by the multiple parallel transmitting loads acts on the target under test. Active adaptive adjustable dual clamping is applied to the rising and falling edges of each sub-pulse in a bipolar parallel current pulse with equal amplitude and in phase. The system detects equal-amplitude, in-phase bipolar parallel current pulses, supply voltage, clamping current, and clamping voltage. as well as Based on the detection results, different PWM timing logic control signals are issued to adjust the equal amplitude and in-phase bipolar current pulses.

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