A pulse power driving source device with LTD and IMG hybrid mode

Abstract

This invention discloses a hybrid pulsed power drive source device, belonging to the field of pulsed power technology. The device includes multiple drive unit groups, each consisting of N stages of drive units connected in series, where N≥2. The first stage in each drive unit group is an LTD mode drive unit, using an externally controlled triggering method; the remaining N-1 stages are IMG mode drive units, using a self-triggered method. The drive unit groups are connected in series to achieve a step-by-step superposition of the output voltage. This invention, through a hybrid topology of LTD and IMG, reduces the amount of amorphous magnetic core used, lowers the complexity and cost of the triggering system, while maintaining high discharge efficiency and voltage superposition stability. It can be used in pulsed power fields such as flash photography, high-power microwaves, inertial confinement fusion, and electromagnetic pulse welding.

Description

Technical Field

[0001] This invention relates to the field of pulsed power technology, and more specifically, to a pulsed power drive source in a hybrid mode of LTD (Linear Transformer Driver) and IMG (Impedance Matching Generator). Background Technology

[0002] Pulsed power technology has wide applications in many fields, including flash photography, high-power microwaves, plasma, inertial confinement fusion, and electromagnetic pulse welding. Currently, common pulsed power drive sources mainly include Marx devices, LTD devices, and IMG devices.

[0003] The Marx device (Marx impulse voltage generator) is a high-voltage pulse multiplication device proposed by Erwin Marx in 1924, which achieves high-voltage pulse multiplication through parallel charging and series discharging of capacitors. It is widely used in high-voltage testing, pulse power, and electromagnetic compatibility. While relatively simple in structure and possessing strong voltage multiplication capability, it is difficult to directly generate nanosecond-level steep-front high-voltage pulses. Furthermore, its size and complexity increase with the number of stages; multi-stage structures occupy a large area, and parasitic inductance / capacitance are difficult to control, affecting waveform fidelity.

[0004] Traditional LTD devices achieve high-voltage output through multi-stage module series connection. Each stage module requires an independent triggering system, making the entire device's triggering system extremely complex, especially in large scientific facilities where 5MV-50MA requires thousands of modules. This not only increases the difficulty of system control but also raises equipment maintenance costs. Furthermore, each LTD module requires an amorphous magnetic core, the high price of which keeps the overall cost of the LTD device high. In addition, the presence of magnetic reluctance in the core causes energy loss, resulting in the LTD's discharge efficiency typically being lower than that of IMG devices.

[0005] IMG devices, with their unique impedance-matching topology, possess high discharge efficiency and do not require complex multi-stage independent triggering systems. However, IMG devices lack internal voltage isolation design. As the number of series stages increases, the superimposed voltage rises exponentially, exponentially increasing the difficulty of insulation design and placing extremely high demands on the equipment's insulation materials and structural design. Therefore, IMG devices struggle to meet the 5MV-50mA output pulse power requirements of controlled nuclear fusion. More critically, the subsequent series units of IMG devices often employ self-triggering mode. As the number of series stages increases, differences in component performance and high voltage levels can easily trigger discharge arcing, leading to a gradual deterioration in voltage superposition and difficulty in stably outputting high-amplitude pulses. Summary of the Invention

[0006] The purpose of this invention is to propose a pulse power drive source device with a hybrid mode of LTD and IMG, which solves the problems of complex triggering system, high cost and low discharge efficiency of traditional LTD devices, as well as the difficulties in insulation design and the susceptibility of voltage superposition effect to series stage of IMG devices. It achieves a balance between controllability, low electrode level, low cost and high efficiency of pulse power drive source.

[0007] To achieve the above objectives, the present invention proposes a pulsed power drive source device in a hybrid mode of LTD and IMG, comprising: Multiple groups of drive units, each group of drive units includes N levels of drive units connected in series, where N≥2; The first-level drive unit in each drive unit group is an LTD mode drive unit, and the remaining N-1 level drive units are IMG mode drive units. The first-level LTD mode drive unit in each drive unit group adopts an external control triggering method, while the remaining IMG mode drive units adopt a self-triggering method. Each group of drive units is connected in series to achieve the step-by-step superposition of output voltages.

[0008] Optionally, each of the drive unit groups includes five drive units connected in series, wherein the first stage is an LTD mode drive unit and the last four stages are IMG mode drive units.

[0009] Optionally, each drive unit includes an upper bus ring, a lower bus ring, and multiple discharge branches connected in parallel in a radial pattern; The upper and lower ends of each discharge branch are connected to the upper and lower bus rings of the drive unit at that stage, respectively. In each group of drive units, the upper bus ring of the previous drive unit is connected to the lower bus ring of the next drive unit to achieve inter-stage series connection. Between multiple groups of drive units, the upper bus ring of the last stage drive unit in the previous group is connected to the lower bus ring of the first stage drive unit in the next group, thus realizing inter-group series connection.

[0010] Optionally, each of the discharge branches includes an upper capacitor, a lower capacitor, and a gas spark switch. The upper capacitor and the lower capacitor are located on the upper and lower sides of the gas spark switch, respectively, and are connected in series with the gas spark switch. The upper capacitor and the lower capacitor are arranged in a mirror image symmetrical arrangement.

[0011] Optionally, in each of the discharge branches, one end of the upper capacitor is connected to the upper end of the gas spark switch through the upper first metal connector, and the other end of the upper capacitor is connected to the upper busbar of the same level through the upper second metal connector. One end of the lower capacitor is connected to the lower end of the gas spark switch via the first metal connector below, and the other end of the lower capacitor is connected to the lower busbar of the same level via the second metal connector below. The upper and lower ends of the gas spark switch are respectively fixed to the upper first metal connector and the lower first metal connector by metal clamps.

[0012] Optionally, the LTD mode driving unit is further provided with an upper magnetic core and a lower magnetic core, the upper magnetic core being disposed on the upper surface of the upper second metal connector, and the lower magnetic core being disposed on the lower surface of the lower second metal connector; Insulating elements are respectively provided between the upper capacitor and the upper magnetic core, and between the lower capacitor and the lower magnetic core.

[0013] Optionally, the IMG mode driving unit has no magnetic core, and an insulating element is provided between the upper capacitor and the lower capacitor.

[0014] Optionally, an isolation element, which is an inductor or a resistor, is provided between two gas spark switches in adjacent discharge branches.

[0015] Optionally, it also includes an impedance-matching transmission line; The transmission line includes an outer cylinder and an inner cylinder, with the inner cylinder located inside the outer cylinder; The outer cylinder is composed of an upper manifold and a lower manifold in each drive unit, and the diameter of the outer cylinder remains fixed. The diameter of the inner cylinder changes exponentially along the transmission direction, so that the characteristic impedance transitions smoothly from the high impedance region at the source end to the low impedance region at the load end; wherein, the transmission direction is from the first stage drive unit to the last stage drive unit. The source end of the transmission line is connected to the upper bus ring of the last stage drive unit of the last group of drive units, and the load end of the transmission line is connected to an external load.

[0016] Optionally, it also includes an external trigger controller, which is connected to all gas spark switches in the first-stage LTD mode drive unit through a high-voltage isolation resistor, and is used to send a trigger control signal to the gas spark switches to trigger the capacitor discharge in the first-stage LTD mode drive unit to generate a high-voltage pulse signal. When the high-voltage pulse signal generated by the first-stage LTD mode drive unit is transmitted to the second-stage IMG mode drive unit, it causes the gas spark switch in the second-stage MG mode drive unit to break down due to overvoltage, thus achieving self-triggering. Subsequent IMG mode drive units at each stage self-trigger in turn, achieving the step-by-step superposition of pulse voltages.

[0017] The beneficial effects of this invention are as follows: 1. Simplify the triggering system and reduce control difficulty: Each group of drive units only needs to externally trigger the first-level LTD mode drive unit. Subsequent multi-level IMG mode drive units adopt a self-triggering mode. Compared with the traditional LTD device, which requires independent triggering for each level, the complexity of the triggering system is greatly reduced, and the control difficulty and maintenance cost are significantly reduced.

[0018] 2. Reduced costs and improved discharge efficiency: Only the first stage of each group uses amorphous magnetic cores. Compared to a full LTD device, the amount of amorphous magnetic cores used is reduced by 80%, effectively reducing equipment costs. At the same time, the last four stages adopt IMG mode, which utilizes its high discharge efficiency to compensate for the low efficiency of LTD mode, resulting in a significant improvement in the overall discharge efficiency of the device.

[0019] 3. Optimized insulation design to improve voltage superposition stability: By setting each N-level as a group (preferably 5 levels), the voltage superposition of the last level in each group is controlled within a reasonable range, avoiding the insulation design difficulties caused by too many series levels in the IMG device. At the same time, the self-triggered mode is only applied to the last four levels within the group, effectively reducing the discharge arcing phenomenon caused by differences in component performance and high voltage levels, ensuring the stability of the voltage superposition effect.

[0020] 4. Flexible and controllable with strong adaptability: The main controller can monitor and adjust the output parameters of each group in real time. According to the needs of different application scenarios, it can flexibly adjust the discharge timing and voltage of each group, change the amplitude, pulse width and repetition frequency of the pulse, etc., and is suitable for a variety of fields such as large scientific facilities, pulsed discharge plasma, particle acceleration, and flash photography.

[0021] The present invention has other features and advantages, which will be apparent from or will be set forth in detail in the accompanying drawings and the following detailed description, which together serve to explain the particular principles of the invention. Attached Figure Description

[0022] The above and other objects, features and advantages of the present invention will become more apparent from the accompanying drawings, in which like reference numerals generally denote like parts.

[0023] Figure 1 This is a schematic diagram of the structure of an LTD mode driving unit according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the discharge branch structure according to an embodiment of the present invention; Figure 3 This is a circuit schematic diagram of an LTD mode driving unit according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of an IMG mode driving unit according to an embodiment of the present invention; Figure 5 This is a circuit schematic diagram of a hybrid pulse power drive source for LTD and IMG according to an embodiment of the present invention. Detailed Implementation

[0024] The invention will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0025] Example

[0026] This embodiment provides a pulse power drive source device in LTD and IMG hybrid mode, including: multiple groups of drive units, each group of drive units including N stages of drive units connected in series, where N≥2; The first-stage drive unit in each drive unit group is an LTD mode drive unit, and the remaining N-1 stages are IMG mode drive units. In this embodiment, each drive unit group includes 5 stages of drive units connected in series, where the first stage is an LTD mode drive unit and the last four stages are IMG mode drive units. The first-stage LTD mode drive unit in each drive unit group uses an external control triggering method, while the remaining IMG mode drive units use a self-triggering method. The drive unit groups are connected in series to achieve the step-by-step superposition of output voltages.

[0027] In this embodiment, the structure of the LTD mode driving unit is as follows: Figure 1 As shown, it includes an upper bus ring 1, a lower bus ring 2, multiple discharge branches 3 connected in parallel in a radial pattern, and an annular upper magnetic core 4 and a lower magnetic core (the lower magnetic core is not shown in the figure due to the viewing angle); the upper and lower ends of each discharge branch 3 are respectively connected to the upper bus ring 1 and the lower bus ring 2 of the driving unit of that stage; the upper bus ring 1 and the lower bus ring 2 are two identical metal rings with completely identical structures.

[0028] The structure of discharge branch 3 is as follows Figure 2 As shown, each discharge branch 3 includes an upper capacitor 301, a lower capacitor 302, and a gas spark switch 303. The upper capacitor 301 and the lower capacitor 302 are located on the upper and lower sides of the gas spark switch 303, respectively, and are connected in series with the gas spark switch 303. The upper capacitor 301 and the lower capacitor 302 are arranged in a mirror image symmetrically. The upper capacitor 301 and the lower capacitor 302 are two identical capacitors.

[0029] In each of the discharge branches 3, one end of the upper capacitor 301 is connected to the upper end of the gas spark switch 303 through the upper first metal connector 304, and the other end of the upper capacitor 301 is connected to the upper bus ring 1 of the same level through the upper second metal connector 306. One end of the lower capacitor 302 is connected to the lower end of the gas spark switch 303 via the lower first metal connector 305, and the other end of the lower capacitor 302 is connected to the lower bus ring 2 of the same level via the lower second metal connector 307. The upper and lower ends of the gas spark switch 303 are respectively fixed to the upper first metal connector 304 and the lower first metal connector 305 by metal clamps.

[0030] In the LTD mode driving unit, the upper magnetic core 4 is disposed on the upper surface of the upper second metal connector 306, and the lower magnetic core is disposed on the lower surface of the lower second metal connector 307; the upper magnetic core 4 and the lower magnetic core are two identical amorphous magnetic cores.

[0031] Preferably, in the LTD mode drive unit, insulating elements are respectively provided between the upper capacitor 301 and the upper magnetic core 4 and between the lower capacitor 302 and the lower magnetic core, and an isolation element is provided between the two gas spark switches 303 in the adjacent discharge branch 3, wherein the isolation element is an inductor or a resistor.

[0032] The circuit schematic of the LTD mode driver unit is as follows: Figure 3 As shown in the figure, C11+, C11+…C1n+ represent the upper capacitor 301 of the first to nth discharge branches 3, C11-, C12-…C1n- represent the lower capacitor 302 of the first to nth discharge branches 3, and K11, K12…K1n represent the gas spark switches 303 of the first to nth discharge branches 3; the two HVDCs represent high-voltage DC charging power supplies, K+ is the switch that controls the parallel charging of the upper capacitors 301 of all discharge branches 3, and K- is the switch that controls the parallel charging of the lower capacitors 302 of all discharge branches 3; M represents the mutual inductance formed by the upper magnetic core 4 and the lower magnetic core, and ZL represents the secondary equivalent load impedance, corresponding to the input impedance of the next stage IMG unit.

[0033] The structure of each IMG mode drive unit is as follows: Figure 4 As shown, similar to the LTD mode drive unit structure, the IMG mode drive unit also includes an upper bus ring 1, a lower bus ring 2, and multiple discharge branches 3 connected in a radial pattern in parallel. The upper and lower ends of each discharge branch 3 are connected to the upper bus ring 1 and lower bus ring 2 of that drive unit, respectively. The difference is that the IMG mode drive unit does not have a magnetic core. The structure of the discharge branch 3 in the IMG mode drive unit is shown in the reference diagram. Figure 3 I won't go into details.

[0034] Preferably, in the IMG mode driving unit, an insulating element is provided between the upper capacitor 301 and the lower capacitor 302, and an isolation element is provided between the two gas spark switches 303 in the adjacent discharge branch 3, wherein the isolation element is an inductor or a resistor.

[0035] In this embodiment, between each level of driving unit in each group of driving units, the upper bus ring 1 of the previous driving unit is connected to the lower bus ring 2 of the next driving unit to achieve inter-level series connection; between multiple groups of driving units, the upper bus ring 1 of the last driving unit in the previous group of driving units is connected to the lower bus ring 2 of the first driving unit in the next group of driving units to achieve inter-group series connection.

[0036] According to the above connection method, the device as a whole progressively increases the voltage from the first-stage LTD mode drive unit of the first-stage drive unit to the last-stage IMG mode drive unit of the last-stage drive unit. In this embodiment, each stage applies a voltage of ±90kV, and the device can stably output a pulse voltage with an amplitude of 1MV, a pulse width of 170ns, and a repetition frequency of 0.1Hz.

[0037] like Figure 5 As shown, in this embodiment, an external trigger controller is also included. The external trigger controller is connected to all the gas spark switches 303 in the first-stage LTD mode drive unit through a high-voltage isolation resistor. It is used to send a trigger control signal to the gas spark switch 303 to trigger the capacitor discharge in the first-stage LTD mode drive unit and generate a high-voltage pulse signal. When the high-voltage pulse signal generated by the first-stage LTD mode drive unit is transmitted to the second-stage IMG mode drive unit, it causes the gas spark switch 303 in the second-stage MG mode drive unit to overvoltage and break down, thus achieving self-triggering. Subsequent IMG mode drive units at each stage self-trigger in turn, realizing the step-by-step superposition of pulse voltages.

[0038] Continue to refer to Figure 5 In this embodiment, the device further includes an impedance matching transmission line; The transmission line includes an outer cylinder and an inner cylinder, with the inner cylinder located inside the outer cylinder; The outer cylinder is composed of an upper manifold 1 and a lower manifold 2 in each drive unit, and the diameter of the outer cylinder remains fixed. The diameter of the inner cylinder changes exponentially along the transmission direction, so that the characteristic impedance transitions smoothly from the high impedance region at the source end to the low impedance region at the load end; wherein, the transmission direction is from the first stage drive unit to the last stage drive unit. The source end of the transmission line is connected to the upper bus ring 1 of the last stage drive unit of the last group of drive units, and the load end of the transmission line is connected to an external load.

[0039] Specifically, assume the relative permittivity of the medium filling the transmission line is ε and the relative permeability is μ. At the source end (near the first stage of the driving source), the inner cylinder diameter is d1, and the outer cylinder diameter is fixed and denoted as D. Then the characteristic impedance Z at the source end is... 01 for:

[0040] At the load end (closer to the external load), the inner cylinder diameter is d. n Then the target characteristic impedance Z at the load end n for:

[0041] To achieve smooth impedance matching from the source to the load, the transmission line is designed as an exponentially graded transmission line with a characteristic impedance Z( l ) Along the axial length of the transmission line l It changes exponentially:

[0042] in: l The position coordinates are along the axial direction of the transmission line, and the range of values ​​is... L is the total length of the gradient line segment; Z0 is the source end ( The characteristic impedance of ), i.e., Z0 = Z 01 ; 'a' is the gradient coefficient, calculated using the formula: a = ; Since the outer cylinder of the transmission line, i.e., the bus ring of the device, has a constant diameter D, the inner cylinder diameter... Follow It changes exponentially and follows an exponential law; its expression is:

[0043] Where d is the inner cylinder at the source end ( l The starting diameter of ), i.e., d = d1; The aforementioned exponentially gradient transmission line achieves impedance matching between the driver and the load, effectively reducing signal reflection and improving pulse transmission quality.

[0044] Taking a series connection of two drive unit groups as an example, the source end of the transmission line is connected to the upper bus loop 1 of the last stage drive unit (5th stage) of the last drive unit group (2nd group), and the load end of the transmission line is connected to an external load (such as an inertial confinement fusion device, X-ray tube, etc.). Through the above-mentioned exponentially graded transmission line, impedance matching between the drive source and the load is achieved, effectively reducing signal reflection and improving pulse transmission quality.

[0045] The working principle of the device in this embodiment is as follows: the LTD mode drive unit adopts an external control triggering method, and the IMG mode drive unit adopts a self-triggering mode. The external control triggering signal triggers the first-stage LTD gas switch, causing the first-stage gas switch to trigger synchronously. When the generated high-voltage pulse signal reaches the second stage, it causes the gas switch of the second-stage IMG unit to break down due to overvoltage, thereby realizing self-triggering. The subsequent 3rd / 4th / 5th stages are triggered sequentially to achieve pulse voltage superposition.

[0046] In one specific example, the device employs two sets of drive units connected in series, with each set containing five drive units. Testing showed that when each stage is subjected to ±90kV, the device can stably output a pulse voltage with an amplitude of 1MV, a pulse width of 170ns, and a repetition frequency of 0.1Hz. Compared to traditional all-LTD devices, this reduces cost by approximately 20%, lowers trigger system complexity by 70%, and provides stable voltage superposition.

[0047] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A pulsed power drive source device in a hybrid mode of LTD and IMG, characterized in that, include: Multiple groups of drive units, each group of drive units includes N levels of drive units connected in series, where N≥2; The first-level drive unit in each drive unit group is an LTD mode drive unit, and the remaining N-1 level drive units are IMG mode drive units. The first-level LTD mode drive unit in each drive unit group adopts an external control triggering method, while the remaining IMG mode drive units adopt a self-triggering method. Each group of drive units is connected in series to achieve the step-by-step superposition of output voltages.

2. The apparatus according to claim 1, characterized in that, Each of the drive unit groups includes five levels of drive units connected in series, wherein the first level is an LTD mode drive unit and the last four levels are IMG mode drive units.

3. The apparatus according to claim 1, characterized in that, Each drive unit includes an upper bus ring, a lower bus ring, and multiple discharge branches connected in parallel in a radial pattern; The upper and lower ends of each discharge branch are connected to the upper and lower bus rings of the drive unit at that stage, respectively. In each group of drive units, the upper bus ring of the previous drive unit is connected to the lower bus ring of the next drive unit to achieve inter-stage series connection. Between multiple groups of drive units, the upper bus ring of the last stage drive unit in the previous group is connected to the lower bus ring of the first stage drive unit in the next group, thus realizing inter-group series connection.

4. The apparatus according to claim 3, characterized in that, Each of the discharge branches includes an upper capacitor, a lower capacitor, and a gas spark switch. The upper capacitor and the lower capacitor are located on the upper and lower sides of the gas spark switch, respectively, and are connected in series with the gas spark switch. The upper capacitor and the lower capacitor are arranged in a mirror image symmetrical arrangement.

5. The apparatus according to claim 4, characterized in that, In each of the discharge branches, one end of the upper capacitor is connected to the upper end of the gas spark switch through the upper first metal connector, and the other end of the upper capacitor is connected to the upper busbar of the same level through the upper second metal connector. One end of the lower capacitor is connected to the lower end of the gas spark switch via the first metal connector below, and the other end of the lower capacitor is connected to the lower busbar of the same level via the second metal connector below. The upper and lower ends of the gas spark switch are respectively fixed to the upper first metal connector and the lower first metal connector by metal clamps.

6. The apparatus according to claim 5, characterized in that, The LTD mode driving unit also includes an annular upper magnetic core and a lower magnetic core. The upper magnetic core is disposed on the upper surface of the upper second metal connector, and the lower magnetic core is disposed on the lower surface of the lower second metal connector. Insulating elements are respectively provided between the upper capacitor and the upper magnetic core, and between the lower capacitor and the lower magnetic core.

7. The apparatus according to claim 4, characterized in that, The IMG mode drive unit has no magnetic core, and an insulating element is provided between the upper capacitor and the lower capacitor.

8. The apparatus according to claim 6 or 7, characterized in that, An isolation element, which is an inductor or a resistor, is provided between two gas spark switches in adjacent discharge branches.

9. The apparatus according to claim 1, characterized in that, It also includes impedance-matched transmission lines; The transmission line includes an outer cylinder and an inner cylinder, with the inner cylinder located inside the outer cylinder; The outer cylinder is composed of an upper manifold and a lower manifold in each drive unit, and the diameter of the outer cylinder remains fixed. The diameter of the inner cylinder changes exponentially along the transmission direction, so that the characteristic impedance transitions smoothly from the high impedance region at the source end to the low impedance region at the load end; wherein, the transmission direction is from the first stage drive unit to the last stage drive unit. The source end of the transmission line is connected to the upper bus ring of the last stage drive unit of the last group of drive units, and the load end of the transmission line is connected to an external load.

10. The apparatus according to claim 4, characterized in that, It also includes an external trigger controller, which is connected to all the gas spark switches in the first-stage LTD mode drive unit through a high-voltage isolation resistor. The external trigger controller is used to send a trigger control signal to the gas spark switches to trigger the capacitor discharge in the first-stage LTD mode drive unit and generate a high-voltage pulse signal. When the high-voltage pulse signal generated by the first-stage LTD mode drive unit is transmitted to the second-stage IMG mode drive unit, it causes the gas spark switch in the second-stage MG mode drive unit to break down due to overvoltage, thus achieving self-triggering. Subsequent IMG mode drive units at each stage self-trigger in turn, achieving the step-by-step superposition of pulse voltages.

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