GW level all-solid-state modular LTD nanosecond square wave pulse generating circuit

Abstract

The purpose of this invention is to address the problems of high design complexity and development difficulty, complex control technology system, and difficulty in achieving electrical isolation between high and low voltage in existing charging power supplies. It provides a GW-level all-solid-state modular LTD nanosecond square wave pulse generating circuit, comprising N LTD primary circuits, 2N primary coils, secondary coils, a transformer core, a control module, and a load circuit, where N≥1. The 2N primary and secondary coils are coaxially wound on the transformer core, with a single primary coil to secondary coil turn ratio of 1:1. Each LTD primary circuit includes M parallel pulse generating units. The power supply terminals of the M parallel pulse generating units are connected to the charging power supply via a charging circuit, and the control terminals are connected to the output terminals of the control module. The output terminals are respectively connected to two corresponding primary coils among the 2N primary coils, where M≥1. The secondary coils are connected to the load circuit.

Description

Technical Field

[0001] This invention relates to a wave pulse generation circuit, specifically a GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit. Background Technology

[0002] Linear transformer drivers (LTDs) are a type of pulsed power technology that uses a multi-stage modular design architecture to superimpose low-voltage pulses step by step, efficiently generating short pulse signals with high voltage and high current. Due to their advantages such as high power density and strong pulse parameter adjustability, they have been widely used in high-power pulse fields such as X-ray imaging, tumor treatment, particle accelerators, inertial confinement fusion, and directed energy equipment.

[0003] Traditional LTD devices use gas switches as the core switching element, but their operation relies on the spark discharge process of the gas switch. This process involves changes in the state of matter, which easily leads to problems such as short lifespan, poor stability, and high maintenance costs for LTD devices. In practical applications, the self-discharge phenomenon of the gas switch or the increase in trigger delay can cause system performance degradation or even failure. Under normal operating conditions, LTD devices generally need to be shut down for gas purification, electrode replacement, and other maintenance work after thousands of cycles, which seriously restricts the continuous operation capability and efficiency of the equipment. With the rapid development of power semiconductor technology, solid-state switches are gradually replacing traditional gas switches to form the solid-state LTD technology system. Compared with traditional LTD devices, solid-state LTD technology exhibits significant technical advantages such as long lifespan, high trigger accuracy, high repetition frequency, and easy modular expansion, becoming a research and application hotspot in the field of pulsed power. For example, in 2010, Jiang Weihua et al. designed a MOSFET-based LTD module (Weihua Jiang. Solid-state LTD Module using power MOSFETs[J]. IEEE Transactions on plasma science. 2010, 38 (10):2730-2733). This LTD system can achieve a maximum output voltage of 29kV and an output current of 240A under a 120Ω load, with a pulse leading edge of 30-40ns and a pulse width that is arbitrarily adjustable in the range of 50-170ns. In 2020, Wang Limin et al. developed a solid-state LTD driver based on IGBT (Wang Limin, Exploratory Research on Solid-State Linear Transformer Driver[D] Doctoral Dissertation of Southwest Jiaotong University, 2022,03). Its output power can reach 3GW, with a pulse leading edge of 30ns and a pulse width of 70ns, further verifying the high-power application potential of solid-state LTD technology.

[0004] Despite the significant breakthroughs achieved in solid-state LTD technology, the following technical bottlenecks still hinder its further industrialization and engineering applications: First, to achieve a compact design for the solid-state LTD driver, the primary energy storage unit must adopt positive and negative charging modes, increasing the design complexity and development difficulty of the charging power supply. Second, the multi-module collaborative operation of the solid-state LTD driver places stringent requirements on synchronous triggering, necessitating high-precision control circuitry, resulting in a relatively complex control system for the charging control system. Third, limited by the voltage withstand level of existing solid-state switches (single module withstand voltage <10kV), achieving high-voltage output requires multi-level module stacking, further increasing the overall structural and control complexity of the solid-state LTD driver. Fourth, from the perspective of system reliability, the solid-state LTD driver contains both high-voltage and low-voltage circuit systems; achieving reliable electrical isolation between high and low voltage at the circuit design level and avoiding mutual interference remains a critical technical challenge that urgently needs to be addressed. Summary of the Invention

[0005] The purpose of this invention is to solve the technical problems of high design complexity and development difficulty, complex control technology system, and difficulty in achieving electrical isolation between high and low voltage in existing solid-state LTD driver charging power supplies, and to provide a GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit.

[0006] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0007] A GW-level all-solid-state modular LTD nanosecond square wave pulse generator circuit, which is special in that:

[0008] It includes N LTD primary circuits, 2N primary coils, secondary coils, transformer cores, and a control module, where N≥1;

[0009] The 2N primary coils and the secondary coils are all coaxially wound on the transformer core, and the ratio of the number of turns per primary coil to that of secondary coil is 1:1.

[0010] Each of the LTD primary circuits includes M parallel pulse generating units; the power supply terminals of the M parallel pulse generating units are connected to the charging power supply, the control terminals are connected to the output terminals of the control module, and the output terminals are respectively connected to one end of two corresponding primary coils among the 2N primary coils. The other ends of the 2N primary coils are all connected to the reference ground, where M≥1.

[0011] The secondary coil is used to connect to an external load circuit.

[0012] Furthermore, the pulse generation unit includes a Blumlein-PFN type pulse transmission line A, a Blumlein-PFN type pulse transmission line B, and a fault detection module;

[0013] The power supply terminal of the fault detection module is connected to the charging power supply, the control terminal is connected to the output terminal of the control module, and the output terminal is connected to the charging side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B respectively.

[0014] The high-voltage output side of Blumlein-PFN type pulse transmission line A is connected to one end of the corresponding primary coil, and the ground side is connected to the other end of the corresponding primary coil.

[0015] The high-voltage output side of the Blumlein-PFN type pulse transmission line B is connected to one end of the corresponding primary coil, and the ground side is connected to the other end of the corresponding primary coil.

[0016] Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B are connected to the reference ground via the grounding side.

[0017] Furthermore, the pulse generation unit also includes two semiconductor switches, which are respectively located on the high-voltage output side of the Blumlein-PFN type pulse transmission line A and the grounding side of the Blumlein-PFN type pulse transmission line B. The control terminals of the two semiconductor switches are respectively connected to the output terminal of the fault detection module.

[0018] Furthermore, the fault detection module includes a charging fault detection circuit and a discharging fault detection circuit;

[0019] The charging fault detection circuit is connected in series between the output terminal of the charging power supply and the power supply terminal of the pulse generation unit. Its signal output terminal is connected to the signal input terminal of the control module to identify the short circuit fault of the pulse generation unit and transmit the short circuit fault signal to the control module.

[0020] The input terminal of the discharge fault detection circuit is connected to the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively, for acquiring current and voltage signals. The signal output terminal is connected to the signal input terminal of the control module.

[0021] Furthermore, the charging fault detection circuit includes a first optocoupler sensor, a detection resistor R1, a solid-state relay, and a second optocoupler sensor. The anode of the first optocoupler sensor is connected to the charging power supply, and the cathode is connected to the charging side of Blumlein-PFN pulse transmission line A and Blumlein-PFN pulse transmission line B through the solid-state relay. The detection resistor R1 is connected in parallel between the cathode and anode of the first optocoupler sensor, and the control terminal of the solid-state relay is connected to the output terminal of the control module. The collector of the first optocoupler sensor is connected to the low-voltage power supply terminal of the control module through a current-limiting resistor R2 and an isolation resistor R3. At the same time, the collector of the first optocoupler sensor is connected to the cathode of the second optocoupler sensor through the current-limiting resistor R2, and the anode of the second optocoupler sensor is connected to the low-voltage power supply terminal of the control module through a pull-up resistor R4. The collector of the second optocoupler sensor is connected to the signal input terminal of the control module to identify short-circuit faults in the pulse generation unit and transmit the short-circuit fault signal to the control module. The emitters of both the first and second optocouplers are connected to reference ground.

[0022] Furthermore, the discharge fault detection circuit includes two Rogowski coils, which are respectively wound in a closed-loop through-core manner on the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B. The discharge current signal output terminals of the two Rogowski coils are connected to the signal input terminal of the control module.

[0023] Furthermore, the pulse generation unit also includes a protection circuit, which includes two output anti-reverse diodes, two charge / discharge freewheeling diodes, two switching freewheeling diodes, and two pulse forming network damping absorption circuits.

[0024] The two output anti-reverse diodes are connected in series on the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively.

[0025] The two charge / discharge freewheeling diodes are connected in parallel between the high-voltage output side and the ground side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively.

[0026] The two freewheeling diodes are connected in reverse parallel between the high-voltage side and the low-voltage side of the two semiconductor switches to suppress the switch damage caused by reverse current passing through the semiconductor switch in a high-resistance state.

[0027] The pulse forming network damping absorption circuit includes a damping absorption diode and a damping matching resistor connected in series. The two pulse forming network damping absorption circuits are connected in series at the ends of the non-semiconductor switch side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively.

[0028] Furthermore, the secondary coil and the primary coil are coaxially mounted to form a coaxial pulse transmission line with gradually changing impedance. The output end of the coaxial pulse transmission line is connected in series with a load resistor and then connected to a reference ground. The load resistor is connected in parallel with the primary coil.

[0029] The characteristic impedance of the pulse generation unit is defined as Z0, and the multi-stage tapered impedance of the coaxial pulse transmission line is defined as Z. n Then Z n =n*Z0 / M, n=1∶N, the final pole characteristic impedance of the coaxial pulse transmission line is equal to the characteristic impedance of the primary coil.

[0030] Furthermore, the load resistor is a water resistor, and the target load resistance value of the water resistor is n*Z0 / M. By adjusting the concentration of the electrolyte in the water resistor, the actual resistance value is adjusted to achieve precise matching with the final stage characteristic impedance of the impedance-gradient coaxial pulse transmission line, thereby achieving impedance matching with the pulse generation unit.

[0031] Compared with the prior art, the present invention has the following advantages:

[0032] (1) The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit of the present invention maintains the positive and negative output of the LTD unit. By setting semiconductor switches on the high-voltage output side of the Blumlein-PFN type pulse transmission line A and the grounding side of the Blumlein-PFN type pulse transmission line B respectively, and connecting the control terminal of the semiconductor switch to the output terminal of the fault detection module respectively, the original bipolar positive and negative charging circuit is optimized into a unipolar charging circuit. The charging power remains unchanged, the charging insulation requirement is reduced by half, and the complexity of the hardware system and the charging control system is reduced by half, and the charging consistency of the pulse generation unit is greatly improved. At the same time, the N×M cascade structure is adopted, and the power can be flexibly expanded by adding or removing N or M. The modular structure facilitates fault isolation and maintenance, and improves the redundancy of the core functions of the system of the present invention.

[0033] (2) The circuit establishment process of the present invention satisfies the time and impedance matching conditions. The total impedance after multi-stage parallel connection is strictly matched with the load impedance by the coaxial pulse transmission line with gradually changing impedance, thereby reducing reflection loss and improving energy transmission efficiency.

[0034] (3) This invention achieves full-link status monitoring by designing a fault detection module and protection circuit, ensuring the long-term stable operation of the system. Attached Figure Description

[0035] Figure 1 This is a circuit diagram of a GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to the present invention;

[0036] Figure 2 This is a circuit diagram of the pulse generation unit in an embodiment of the present invention;

[0037] Figure 3 This is a circuit schematic diagram of the charging fault detection module in an embodiment of the present invention;

[0038] Figure 4 This is a schematic diagram of the protection circuit in an embodiment of the present invention.

[0039] The attached figures are labeled as follows:

[0040] 1-LTD primary circuit, 2-charging power supply, 3-control module, 4-pulse generation unit, 5-fault detection module, 6-solid-state relay, 7-first optical coupling sensor, 8-second optical coupling sensor, 9-output reverse protection diode, 10-charge and discharge freewheeling diode, 11-Rogowski coil, 12-switching freewheeling diode, 13-damping absorption diode. Detailed Implementation

[0041] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0042] like Figure 2As shown, this embodiment provides a GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit, including an LTD primary circuit 1, a primary coil, a secondary coil, a transformer core, and a control module 3. Both the primary and secondary coils are coaxially wound on the transformer core. The LTD primary circuit 1 includes a pulse generation unit 4, which includes a Blumein-PFN type pulse transmission line A, a Blumein-PFN type pulse transmission line B, two semiconductor switches, and a fault detection module 5. The power supply terminal of the fault detection module 5 is connected to a charging power supply 2, and its control terminal is connected to the output terminal of the control module 3. The output terminal is connected to both the Blumein-PFN type pulse transmission line A and the Blumein-PFN type pulse transmission line B. The charging side of B; the high-voltage output side of Blumlein-PFN type pulse transmission line A is connected to one end of a corresponding primary coil, and the ground side is connected to the other end of a corresponding primary coil; the high-voltage output side of Blumlein-PFN type pulse transmission line B is connected to one end of another corresponding primary coil, and the ground side is connected to the other end of another corresponding primary coil; Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B are connected through the ground side and connected to the reference ground; two semiconductor switches are respectively set on the high-voltage output side of Blumlein-PFN type pulse transmission line A and the ground side of Blumlein-PFN type pulse transmission line B; the secondary coil is connected to the external load circuit.

[0043] The solution in this embodiment is further modularized, adopting an N×M level structure, such as... Figure 1As shown, the system employs N LTD primary circuits 1, 2N primary coils, secondary coils, a transformer core, and a control module 3, where N ≥ 1. The 2N primary and secondary coils are coaxially wound on the transformer core, with a single primary coil to secondary coil turn ratio of 1:1. Each LTD primary circuit 1 includes M parallel pulse generation units 4. Each pulse generation unit 4 includes a Blumlein-PFN pulse transmission line A, a Blumlein-PFN pulse transmission line B, two semiconductor switches, and a fault detection module 5. The power supply terminal of the fault detection module 5 is connected to the charging power supply 2, and its control terminal is connected to the output terminal of the control module 3. The output terminal is connected to the Blumlein-PFN pulse transmission line A and the Blumlein-PFN pulse transmission line B, respectively. The charging side of the N-type pulse transmission line B; the high-voltage output side of the Blumlein-PFN type pulse transmission line A is connected to one end of a corresponding primary coil, and the ground side is connected to the other end of a corresponding primary coil; the high-voltage output side of the Blumlein-PFN type pulse transmission line B is connected to one end of another corresponding primary coil, and the ground side is connected to the other end of another corresponding primary coil; the Blumlein-PFN type pulse transmission line A and the Blumlein-PFN type pulse transmission line B are connected through the ground side and connected to the reference ground; two semiconductor switches are respectively set on the high-voltage output side of the Blumlein-PFN type pulse transmission line A and the ground side of the Blumlein-PFN type pulse transmission line B, where M≥1; the secondary coil is connected to the external load circuit.

[0044] The fault detection module 5 includes a charging fault detection circuit and a discharging fault detection circuit; the charging fault detection circuit is as follows: Figure 3As shown, the system includes a first optical coupling sensor 7, a solid-state relay 6, and a second optical coupling sensor 8. The anode of the first optical coupling sensor 7 is connected to the charging power supply 2, and the cathode is connected to the charging side of Blumlein-PFN pulse transmission lines A and Blumlein-PFN pulse transmission lines B through the solid-state relay 6. A detection resistor R1 is connected in parallel between the anode and the cathode, causing the diode internal resistance of the first optical coupling sensor 7 to be shunt to the detection resistor R1. The collector of the first optical coupling sensor 7 is connected to the low-voltage power supply terminal of the control module 3 through a current-limiting resistor R2 and an isolation resistor R3, and simultaneously, the collector is connected to the cathode of the second optical coupling sensor 8 through the current-limiting resistor R2. The anode of the second optical coupling sensor 8 is connected to the low-voltage power supply terminal of the control module 3 through a pull-up resistor R4, and the collector of the second optical coupling sensor 8 is connected to the control module 3 through the control module 3. The signal input terminal of module 3 is connected to identify the short-circuit fault of the pulse generation unit 4 and transmit the short-circuit fault signal to the control module 3; the emitters of the first optical coupling sensor 7 and the second optical coupling sensor 8 are connected to the reference ground; when the total charging current exceeds the preset short-circuit current threshold, the first optical coupling sensor 7 and the second optical coupling sensor 8 are triggered to emit light, which is converted into an electrical signal after photoelectric conversion, used to characterize the trigger conduction state of the pulse generation unit 4 and report the fault information to the control module 3; the discharge fault detection circuit includes two Rogowski coils, which are respectively nested in a closed-loop through-core manner on the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, and the discharge current signal output terminals of the two Rogowski coils are connected to the signal input terminal of the control module 3.

[0045] To ensure the long-term stable operation of the system, pulse generation unit 4 is also equipped with protection circuits such as... Figure 4 As shown, the protection circuit includes multiple output anti-reverse diodes 9, charge / discharge freewheeling diodes 10, switching freewheeling diodes 12, and a pulse forming network damping absorption circuit.

[0046] Multiple output anti-reverse diodes 9 are connected in series at the output terminal of the pulse generation unit (4) to protect the early-conducting component from damage to the late-conducting component in the case of asynchronous discharge.

[0047] Multiple charge / discharge freewheeling diodes 10 are connected in parallel between the high-voltage output side and the ground side of Blumlein-PFN pulse transmission line A and Blumlein-PFN pulse transmission line B, respectively. During the charging phase, a charging-to-ground loop is formed. During the discharging phase, when the primary circuit 1 of LTD is under asynchronous discharging conditions, a discharging freewheeling loop is formed to avoid switching damage caused by the early-conducting component charging the late-conducting component.

[0048] The freewheeling diode 12 is connected in antiparallel between the high-voltage side and the low-voltage side of the semiconductor switch to suppress the switch damage caused by reverse current passing through the semiconductor switch in a high-resistance state.

[0049] The pulse forming network damping absorption circuit includes a damping absorption diode 13 and a damping matching resistor, which are connected in series at the non-semiconductor switch ends of Blumblein-PFN type pulse transmission line A and Blumblein-PFN type pulse transmission line B.

[0050] To achieve impedance matching for electromagnetic wave transmission along the primary and secondary coaxial lines, the secondary coil and primary coil are coaxially nested, forming a coaxial pulse transmission line with gradually varying impedance. A water resistor is connected in series with the output of the coaxial pulse transmission line and then connected to a reference ground. The water resistor is connected in parallel with the primary coil. The characteristic impedance of the pulse generation unit 4 is defined as Z0, and the multi-stage gradually varying impedance of the coaxial pulse transmission line is defined as Z... n Then Z n =n*Z0 / M, n=1∶N, the final characteristic impedance of the coaxial pulse transmission line is equal to the characteristic impedance of the primary coil, and the target load resistance of the water resistor is n*Z0 / M. By adjusting the concentration of electrolyte in the water resistor to adjust the actual resistance value, the precise matching with the final characteristic impedance of the impedance-gradient coaxial pulse transmission line is achieved, thereby achieving impedance matching with the pulse generation unit 4.

[0051] Taking the design of an LTD nanosecond square wave pulse generator circuit with a pulse source output power of 5GW, a pulse width of 70ns, and a characteristic impedance of 50Ω as an example:

[0052] Pulse generation unit 4 adopts the Blumlein-PFN type pulse forming line technology, with an output pulse width of 2T0, where T0 is the propagation delay of a single Blumlein-PFN type pulse transmission line A or B, which should be 35ns in this example; the propagation delay of a single Blumlein-PFN type pulse transmission line A or B... Where L0 is the inductance, C0 is the capacitance, and k is the number of segments of a single Blummlein-PFN pulse transmission line A or B. In this example, the capacitance is 0.8nF and the inductance is 4nH, so the output pulse width 2T0 can be calculated to be 71.5ns.

[0053] The characteristic impedance of pulse generation unit 4 is Z0. Z pfl The characteristic impedance of a single Blumlein-PFN type pulse transmission line A or B. Substituting the capacitance of 0.8nF and the inductance of 4nH, we can calculate that the characteristic impedance of the primary pulse generation unit 4 is 9Ω.

[0054] According to the design requirements, a pulse source with a characteristic impedance of 50Ω and an output power of 5GW needs an output voltage of 500kV and an output current of 10kA. The output voltage and output current of pulse generation unit 4 are 15kV and 1.67kA, respectively, with a characteristic output power of 25MW. Based on this, the number of single-stage parallel connections M is calculated to be 10 / 1.67 = 6, and the number of series stages N is calculated to be 34. Therefore, the total output power P can be calculated to be 5.1GW.

[0055] The above are merely embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the invention by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the technical solutions of the present invention should be included within the scope of protection of the present invention. Furthermore, it should be noted that the accompanying drawings are merely illustrative and are not drawn to scale, and should not be construed as limiting the actual scope of protection claimed by the present invention.

Claims

1. A GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit, characterized in that: It includes N LTD primary circuits (1), 2N primary coils, secondary coils, transformer cores and control modules (3), where N≥1; The 2N primary coils and the secondary coils are all coaxially wound on the transformer core, and the ratio of the number of turns per primary coil to that of secondary coil is 1:

1. Each of the LTD primary circuits (1) includes M parallel pulse generating units (4); the power supply terminals of the M parallel pulse generating units (4) are connected to the charging power supply (2), the control terminals are connected to the output terminals of the control module (3), and the output terminals are respectively connected to one end of two corresponding primary coils among the 2N primary coils. The other ends of the 2N primary coils are all connected to the reference ground, where M≥1. The secondary coil is used to connect to an external load circuit.

2. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 1, characterized in that: The pulse generation unit (4) includes a Blumlein-PFN type pulse transmission line A, a Blumlein-PFN type pulse transmission line B, and a fault detection module (5). The power supply end of the fault detection module (5) is connected to the charging power supply (2), the control end is connected to the output end of the control module (3), and the output end is connected to the charging side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B respectively. The high-voltage output side of Blumlein-PFN type pulse transmission line A is connected to one end of a corresponding primary coil, and the ground side is connected to the other end of a corresponding primary coil. The high-voltage output side of the Blumlein-PFN type pulse transmission line B is connected to one end of the corresponding primary coil, and the ground side is connected to the other end of the corresponding primary coil. Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B are connected to the reference ground via the grounding side.

3. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 2, characterized in that: The pulse generation unit (4) also includes two semiconductor switches, which are respectively located on the high-voltage output side of the Blumlein-PFN pulse transmission line A and the grounding side of the Blumlein-PFN pulse transmission line B. The control terminals of the two semiconductor switches are respectively connected to the output terminals of the fault detection module (5).

4. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 3, characterized in that: The fault detection module (5) includes a charging fault detection circuit and a discharging fault detection circuit; The charging fault detection circuit is connected in series between the output end of the charging power supply (2) and the power supply end of the pulse generation unit (4). Its signal output end is connected to the signal input end of the control module (3) to identify the short circuit fault of the pulse generation unit (4) and transmit the short circuit fault signal to the control module (3). The input terminal of the discharge fault detection circuit is connected to the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B respectively, and is used to collect current and voltage signals. The signal output terminal is connected to the signal input terminal of the control module (3).

5. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 4, characterized in that: The charging fault detection circuit includes a first optical coupling sensor (7), a detection resistor R1, a solid-state relay (6), and a second optical coupling sensor (8). The anode of the first optical coupling sensor (7) is connected to the charging power supply (2), and the cathode is connected to the charging side of Blumlein-PFN pulse transmission line A and Blumlein-PFN pulse transmission line B through the solid-state relay (6). The detection resistor R1 is connected in parallel between the cathode and anode of the first optical coupling sensor (7), and the control terminal of the solid-state relay (6) is connected to the output terminal of the control module (3). The collector of the first optical coupling sensor (7) is connected to the current-limiting current. Resistor R2 and isolation resistor R3 are connected to the low-voltage power supply terminal of the control module (3). At the same time, the collector of the first optical coupling sensor (7) is connected to the cathode of the second optical coupling sensor (8) through the current limiting resistor R2. The anode of the second optical coupling sensor (8) is connected to the low-voltage power supply terminal of the control module (3) through the pull-up resistor R4. The collector of the second optical coupling sensor (8) is connected to the signal input terminal of the control module (3) to identify the short circuit fault of the pulse generation unit (4) and transmit the short circuit fault signal to the control module (3). The emitters of the first optical coupling sensor (7) and the second optical coupling sensor (8) are both connected to the reference ground.

6. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 4, characterized in that: The discharge fault detection circuit includes two Rogowski coils (11). The two Rogowski coils (11) are respectively mounted on the high voltage output side of Blumlein-PFN pulse transmission line A and Blumlein-PFN pulse transmission line B in a closed-loop through-core manner. The discharge current signal output terminals of the two Rogowski coils (11) are connected to the signal input terminal of the control module (3).

7. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 4, characterized in that: The pulse generation unit (4) also includes a protection circuit, which includes two output anti-reverse diodes (9), two charge-discharge freewheeling diodes (10), two switching freewheeling diodes (12), and two pulse forming network damping absorption circuits. The two output anti-reverse diodes (9) are connected in series on the high-voltage output side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively; The two charge-discharge freewheeling diodes (10) are connected in parallel between the high-voltage output side and the ground side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively. The two freewheeling diodes (12) are connected in reverse parallel between the high voltage side and the low voltage side of the two semiconductor switches to suppress the switch damage caused by reverse current passing through the semiconductor switch in a high-resistance state. The pulse forming network damping absorption circuit includes a damping absorption diode (13) and a damping matching resistor connected in series. The two pulse forming network damping absorption circuits are connected in series at the ends of the non-semiconductor switch side of Blumlein-PFN type pulse transmission line A and Blumlein-PFN type pulse transmission line B, respectively.

8. The GW-level all-solid-state modular LTD nanosecond square wave pulse generation circuit according to claim 2, characterized in that: The secondary coil and the primary coil are coaxially mounted to form a coaxial pulse transmission line with gradually changing impedance. The output end of the coaxial pulse transmission line is connected in series with a load resistor and then connected to the reference ground. The load resistor is connected in parallel with the primary coil. The characteristic impedance of the pulse generation unit (4) is defined as Z0, and the multi-stage tapered impedance of the coaxial pulse transmission line is defined as Z. n Then Z n =n*Z0 / M, n=1∶N, the final pole characteristic impedance of the coaxial pulse transmission line is equal to the characteristic impedance of the primary coil.

9. A GW-level all-solid-state modular LTD nanosecond square wave pulse generating circuit according to claim 8, characterized in that: The load resistor is a water resistor, and the target load resistance of the water resistor is n*Z0 / M. The actual resistance value is adjusted by adjusting the concentration of electrolyte in the water resistor, so as to achieve precise matching with the final stage characteristic impedance of the impedance-gradient coaxial pulse transmission line, and thus achieve impedance matching with the pulse generation unit (4).

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