A high-voltage nanosecond pulse shaping device and method based on magnetic devices

Abstract

This invention discloses a high-voltage nanosecond pulse shaping device and method based on magnetic devices. The device includes: a first magnetic transmission line and a second magnetic transmission line, with their input ends connected in parallel and connected to an initial pulse source; the output end of the first magnetic transmission line is connected to a load terminal; the output end of the second magnetic transmission line is short-circuited to ground; the first magnetic transmission line includes a first magnetic ring arranged along the axial direction and an outer magnetic field coil; the second magnetic transmission line includes a second magnetic ring arranged along the axial direction. Based on the current-dependent nonlinear permeability effect of the magnetic ring, this device simultaneously achieves pulse rise time compression, fall time truncation, pulse width shortening, and suppression of pre-pulse and tail oscillations through the rising sharpening effect of the first magnetic transmission line and the falling truncation effect of the second magnetic transmission line. This overcomes the limitation of single nonlinear transmission line or magnetic switching technology, which can only optimize single pulse parameters, and can obtain high-quality pulse waveforms at the load terminal.

Description

Technical Field

[0001] This invention relates to the field of pulse power technology, and in particular to a high-voltage nanosecond pulse shaping device and method based on magnetic devices. Background Technology

[0002] High-voltage nanosecond pulses are characterized by high amplitude, fast edge, narrow pulse width, wide spectrum, and strong instantaneous power, and are widely used in cutting-edge fields such as plasma industrial processing, non-thermal biomedical electroporation, and particle accelerators. Existing high-voltage nanosecond pulse generation technologies are mainly divided into two categories: electric field energy storage and magnetic field energy storage. Electric field energy storage technologies (such as the all-solid-state nanosecond pulse generator based on dual-channel Marx tangency disclosed in CN111082784A) are represented by Marx generators and inductive superposition circuits, achieving pulse output through the rapid conduction of switching devices. Magnetic field energy storage technologies (such as the all-solid-state repetitive frequency nanosecond pulse source disclosed in CN102158088) are mainly based on the nonlinear conduction and cutoff characteristics of devices such as semiconductor circuit breakers (SOS) and drift step recovery diodes (DSRDs), capable of generating high-voltage pulses within a relatively short timescale.

[0003] In the existing technology, the above-mentioned methods for generating high-voltage nanosecond pulses have obvious shortcomings in terms of pulse waveform quality. These shortcomings are mainly manifested in the presence of pre-pulse interference, slow rise / fall times, and obvious pulse tail oscillations, making it difficult to apply to application scenarios with high pulse waveform quality requirements.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] To address the shortcomings in pulse waveform quality during high-voltage nanosecond pulse generation in existing technologies, primarily manifested in pre-pulse interference, slow rise / fall times, and significant pulse tail oscillations, which make them unsuitable for applications requiring high pulse waveform quality, this invention provides a high-voltage nanosecond pulse shaping device and method based on magnetic devices.

[0006] This invention is achieved through the following technical solution: A high-voltage nanosecond pulse shaping device based on magnetic devices, wherein the high-voltage nanosecond pulse shaping device based on magnetic devices comprises: A first magnetic transmission line and a second magnetic transmission line are connected in parallel at their input ends and connected to the initial pulse source; the output end of the first magnetic transmission line is connected to the load terminal; the output end of the second magnetic transmission line is short-circuited to ground. The first magnetic transmission line includes a first magnetic ring disposed axially inside and a magnetic field coil disposed on the outside, used to sharpen the rising edge of the pulse and suppress the reflection of the pre-pulse; The second magnetic transmission line includes a second magnetic ring disposed axially inside, used to achieve pulse falling edge truncation and tail oscillation suppression.

[0007] The high-voltage nanosecond pulse shaping device based on magnetic devices, wherein the first magnetic transmission line includes a first central conductor, a first magnetic ring and a first outer conductor coaxially arranged from the inside to the outside, the magnetic field coil is sleeved on the outside of the first outer conductor, and a first insulating medium is filled between the first magnetic ring and the first outer conductor. The second magnetic transmission line includes a second central conductor, a second magnetic ring, and a second outer conductor, which are coaxially arranged from the inside to the outside, with a second insulating medium filling the space between the second magnetic ring and the second outer conductor.

[0008] The high-voltage nanosecond pulse shaping device based on magnetic devices, wherein the first insulating medium and the second insulating medium are respectively one of air, insulating oil, and polyethylene.

[0009] The high-voltage nanosecond pulse shaping device based on magnetic devices, wherein the length of the first magnetic ring is greater than the length of the second magnetic ring; The first magnetic ring includes a plurality of first sub-magnetic rings; The second magnetic ring includes a plurality of second sub-magnetic rings, the second sub-magnetic rings having the same magnetic parameters as the first sub-magnetic ring; the diameter of the second sub-magnetic ring is larger than the diameter of the first sub-magnetic ring. Both the first and second sub-magnetic rings are Ni-Zn ferrite magnetic rings.

[0010] The high-voltage nanosecond pulse shaping device based on magnetic devices, wherein the first center conductor and the second center conductor are both aluminum alloy cylinders, and the diameter of the first center conductor is smaller than the diameter of the second center conductor; The first outer conductor and the second outer conductor are both metal tubes, and the diameter of the first outer conductor is smaller than the diameter of the second outer conductor.

[0011] The high-voltage nanosecond pulse shaping device based on magnetic devices includes a magnetic field coil comprising an epoxy tube and a solenoid wound around the outside of the epoxy tube, wherein the current of the magnetic field coil is adjustable.

[0012] A high-voltage nanosecond pulse shaping method based on magnetic devices is applied to the aforementioned high-voltage nanosecond pulse shaping device based on magnetic devices. The high-voltage nanosecond pulse shaping method based on magnetic devices includes: When the magnetic field coil of the first magnetic transmission line is energized, an axial bias magnetic field is generated inside the first magnetic transmission line. The initial high-voltage nanosecond pulse is simultaneously fed into the first magnetic transmission line and the second magnetic transmission line. The high-resistivity state of the first magnetic transmission line suppresses the prepulse, and the damped gyromagnetic precession of the first magnetic ring moment in the first magnetic transmission line compresses the rising edge of the pulse. The second magnetic ring within the second magnetic transmission line reaches the volt-second integral saturation threshold, generating a fast falling edge and suppressing pulse tail oscillation; The pulse continues to propagate within the first magnetic transmission line and the rising edge is further sharpened. The second magnetic transmission line saturates and truncates the pulse tail through the second magnetic ring, and the shaped pulse is applied to the load terminal.

[0013] The high-voltage nanosecond pulse shaping method based on magnetic devices, wherein energizing the magnetic field coil of the first magnetic transmission line to generate an axial bias magnetic field inside the first magnetic transmission line includes: The magnitude of the current passing through the solenoid in the magnetic field coil is adjusted to control the strength of the axial bias magnetic field, so that the pre-pulse suppression degree and the rising edge sharpening degree are continuously adjustable.

[0014] The high-voltage nanosecond pulse shaping method based on magnetic devices, wherein the step of suppressing the prepulse through the high-resistivity state of the first magnetic transmission line and compressing the pulse rising edge through the damped gyromagnetic precession of the first magnetic ring moment within the first magnetic transmission line includes: The prepulse is too small to saturate the first magnetic ring. Under the action of the axial bias magnetic field, the first magnetic transmission line exhibits high impedance, which causes the prepulse to be reflected and suppressed. The main pulse causes the first magnetic ring to saturate rapidly, the characteristic impedance of the first magnetic transmission line is matched with the load termination, and the pulse leading edge is continuously compressed and sharpened.

[0015] The high-voltage nanosecond pulse shaping method based on magnetic devices, wherein the second magnetic ring within the second magnetic transmission line reaches the volt-second integration saturation threshold, generating a fast falling edge and suppressing pulse tail oscillation includes: The pulse voltage accumulates volt-second integrals on the second magnetic ring. When the integral value reaches the saturation threshold, the second magnetic ring quickly saturates, making the second magnetic transmission line a low-impedance path and short-circuiting the pulse tail to ground. The second magnetic transmission line forms a steep falling edge after being short-circuited, thus eliminating tail oscillations.

[0016] The beneficial effects of this invention are as follows: Based on the current-dependent nonlinear permeability effect of a magnetic ring, this invention simultaneously achieves pulse rise time compression, fall time truncation, pulse width shortening, and suppression of pre-pulse and tail oscillations through the rising sharpening effect of the first magnetic transmission line and the falling truncation effect of the second magnetic transmission line. This solves the problem that a single nonlinear transmission line or magnetic switch technology can only optimize a single pulse parameter. Ultimately, a high-quality pulse waveform with fast rise time, fast fall time, narrow pulse width, and low oscillation is obtained at the load terminal, thus making it applicable to application scenarios with high pulse waveform quality requirements. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the high-voltage nanosecond pulse shaping device based on magnetic devices according to the present invention; Figure 2 This is a cross-sectional view of the first transmission line in the high-voltage nanosecond pulse shaping device based on magnetic devices of the present invention; Figure 3 This is a cross-sectional view of the second transmission line in the high-voltage nanosecond pulse shaping device based on magnetic devices of the present invention; Figure 4 This is a simulation waveform of the high-voltage nanosecond pulse shaping device based on magnetic devices in this invention. Figure 5 These are experimental waveforms when the high-voltage nanosecond pulse shaping device based on magnetic devices of this invention is applied. Figure 6 This is a schematic diagram of the pulse propagation and shaping process of the present invention; Figure 7 This is a flowchart of the high-voltage nanosecond pulse shaping method based on magnetic devices according to the present invention.

[0018] exist Figures 1 to 7 In the middle: 100, first magnetic transmission line; 110, first center conductor; 120, first magnetic ring; 130, first outer conductor; 140, first insulating medium; 200, second magnetic transmission line; 210, second center conductor; 220, second magnetic ring; 230, second outer conductor; 240, second insulating medium; 300, initial pulse source; 400, load terminal; 500, magnetic field coil; 510, epoxy tube; 520, solenoid. Detailed Implementation

[0019] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0020] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0021] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0022] In the existing technology, the above-mentioned methods for generating high-voltage nanosecond pulses have obvious shortcomings in terms of pulse waveform quality. These shortcomings are mainly manifested in the presence of pre-pulse interference, slow rise / fall times, and obvious pulse tail oscillations, making it difficult to apply to application scenarios with high pulse waveform quality requirements.

[0023] To address the aforementioned problems in the prior art, this invention provides a device-based high-voltage nanosecond pulse shaping apparatus, such as... Figure 1 , Figure 2 and Figure 3 As shown, the device-based high-voltage nanosecond pulse shaping device includes: a first magnetic transmission line 100 and a second magnetic transmission line 200. The input terminals of the first magnetic transmission line 100 and the second magnetic transmission line 200 are connected in parallel and connected to the initial pulse source 300. The output terminal of the first magnetic transmission line 100 is connected to the load terminal 400. The output terminal of the second magnetic transmission line 200 is short-circuited to ground. The first magnetic transmission line 100 includes a first magnetic ring 120 disposed axially inside and a magnetic field coil 500 disposed on the outside, which are used to sharpen the pulse rising edge and suppress pre-pulse reflection. The second magnetic transmission line 200 includes a second magnetic ring 220 disposed axially inside, which are used to cut off the pulse falling edge and suppress tail oscillation.

[0024] This invention is based on the current-dependent nonlinear permeability effect of a magnetic ring. Through the rising sharpening effect of the first magnetic transmission line 100 and the falling truncation effect of the second magnetic transmission line 200, it simultaneously achieves pulse rise time compression, fall time truncation, pulse width shortening, and suppression of pre-pulse and tail oscillation. This solves the problem that a single nonlinear transmission line or magnetic switch technology can only optimize a single pulse parameter. Finally, a high-quality pulse waveform with fast rise time, fast fall time, narrow pulse width, and low oscillation is obtained at the load terminal 400, so it can be applied to application scenarios with high pulse waveform quality requirements.

[0025] In the above embodiments, such as Figure 1 As shown, the main body of the high-voltage nanosecond pulse shaping device based on magnetic devices of the present invention consists of a first magnetic transmission line 100 and a second magnetic transmission line 200. The input ends of the two are connected in parallel and connected to the initial pulse source 300 to realize synchronous input of pulse signals. The output end of the first magnetic transmission line 100 is directly connected to the load terminal 400, which adopts a standard 50Ω impedance matching design. The output end of the second magnetic transmission line 200 is directly short-circuited to ground and is not connected to the load signal loop, but is only used as a pulse tail truncation branch. The first magnetic transmission line 100 has a first magnetic ring 120 axially arranged inside and a magnetic field coil 500 axially arranged outside. By adjusting the coil current, the axial bias magnetic field strength can be changed to realize the continuous adjustability of the pre-pulse suppression degree and the rising edge sharpening intensity. The second magnetic transmission line 200 has a second magnetic ring 220 axially arranged inside. Relying on the volt-second integral saturation characteristic of the magnetic ring, it quickly becomes a low-impedance path when the saturation threshold is reached, short-circuiting the pulse tail to ground, realizing rapid truncation of the falling edge and oscillation suppression.

[0026] In one specific embodiment of the present invention, such as Figure 2 As shown, the first magnetic transmission line 100 includes a first central conductor 110, a first magnetic ring 120, and a first outer conductor 130 coaxially arranged from the inside out. A magnetic field coil 500 is sleeved outside the first outer conductor 130. A first insulating medium 140 is filled between the first magnetic ring 120 and the first outer conductor 130. In a specific embodiment, the first central conductor 110 is an aluminum alloy cylindrical structure with a diameter of 6 mm, the first outer conductor 130 is a metal tube with an inner diameter of 15.6 mm, and transformer oil is filled between the first magnetic ring 120 and the first outer conductor 130 as the first insulating medium 140. The first magnetic ring 120 is made of Ni-Zn ferrite material, specifically a first sub-magnetic ring with an outer diameter of 10 mm, an inner diameter of 6 mm, and a height of 5 mm, with a total of 14 rings and a total length of 70 mm. The first magnetic ring 120 has a relative initial permeability of 1000, a saturation magnetic induction intensity of 0.28 T, and a coercivity of 40 A / m.

[0027] Furthermore, such as Figure 3As shown, the second magnetic transmission line 200 includes a second central conductor 210, a second magnetic ring 220, and a second outer conductor 230 coaxially arranged from the inside out, with a second insulating medium 240 filling the space between the second magnetic ring 220 and the second outer conductor 230. The second central conductor 210 is an aluminum alloy cylindrical structure with a diameter of 7 mm, and the second outer conductor 230 is a metal tube with an inner diameter of 18 mm. Air is used as the second insulating medium 240 between the second magnetic ring 220 and the second outer conductor 230. The second magnetic ring 220 is also made of Ni-Zn ferrite material, specifically a second sub-magnetic ring with an outer diameter of 13 mm, an inner diameter of 7 mm, and a height of 5 mm. A total of 11 sub-magnetic rings are provided, with a total length of 55 mm, and the magnetic parameters are consistent with those of the first magnetic ring 120.

[0028] In a preferred embodiment of the present invention, the first insulating medium 140 and the second insulating medium 240 are respectively one of air, insulating oil, and polyethylene. In this embodiment, transformer oil is preferably used as the first insulating medium 140 and air is used as the second insulating medium 240. Transformer oil has a high withstand voltage rating and good heat dissipation, which can meet the high voltage transmission and stable operation requirements of the first magnetic transmission line 100; air has a low dielectric constant and fast pulse transmission speed, which can improve the cutoff response speed of the second magnetic transmission line 200 and make the falling edge steeper.

[0029] In one specific embodiment of the present invention, the length of the first magnetic ring 120 should be greater than the length of the second magnetic ring 220; the first magnetic ring 120 includes a plurality of first sub-magnetic rings, and the second magnetic ring 220 includes a plurality of second sub-magnetic rings. The second sub-magnetic rings have the same magnetic parameters as the first sub-magnetic rings, and the diameter of the second sub-magnetic rings is greater than the diameter of the first sub-magnetic rings. In this embodiment, the total length of the first magnetic ring 120 is 70 mm, the total length of the second magnetic ring 220 is 55 mm, the outer diameter of the first sub-magnetic rings is 10 mm, and the outer diameter of the second sub-magnetic rings is 13 mm. The size matching and coaxial structure design can ensure stable transmission and cutting effects.

[0030] More specifically, both the first and second sub-magnetic rings are Ni-Zn ferrite magnetic rings. This material can rapidly enter a saturation state under nanosecond pulse excitation, exhibiting a significant change in permeability. This satisfies the dual operational requirements of 100V nonlinear impedance transformation of the first magnetic transmission line and 200V-second integral saturation of the second magnetic transmission line, ensuring stable and reliable shaping results.

[0031] In one specific embodiment of the present invention, the first center conductor 110 and the second center conductor 210 are both aluminum alloy cylinders, and the diameter of the first center conductor 110 is smaller than the diameter of the second center conductor 210. In this embodiment, the diameter of the first center conductor 110 is 6mm and the diameter of the second center conductor 210 is 7mm. The aluminum alloy material has high conductivity, light weight, and good mechanical strength, making it suitable for low-loss transmission of high-voltage nanosecond pulses.

[0032] Furthermore, the first outer conductor 130 and the second outer conductor 230 are both metal tubes, with the diameter of the first outer conductor 130 being smaller than that of the second outer conductor 230. In this embodiment, the inner diameter of the first outer conductor 130 is 15.6 mm, and the inner diameter of the second outer conductor 230 is 18 mm. The metal tubes provide good electromagnetic shielding, reduce external interference, and ensure the purity of the pulse waveform.

[0033] In one specific embodiment of the present invention, the magnetic field coil 500 includes an epoxy tube 510 and a solenoid 520 wound around the outside of the epoxy tube 510; the current of the magnetic field coil 500 is adjustable. In this embodiment, the magnetic field coil 500 is an eight-layer solenoid 520 structure with a total of 744 turns, wound on the epoxy tube 510. When an adjustable DC current is applied, it can generate a continuously adjustable axial bias magnetic field within the range of 0 to 28 kA / m. By adjusting the current magnitude, the initial operating point of the first magnetic ring 120 can be precisely controlled, optimizing the rising edge sharpening and pre-pulse suppression effects.

[0034] The pulse shaping principle and parameter design of this invention are as follows: The first magnetic transmission line 100 is used to achieve rising edge sharpening. Its working principle is based on the current-dependent nonlinear permeability effect of the magnetic ring, specifically as follows: The high-amplitude current at the rising edge of the pulse causes the ferrite to rapidly saturate, resulting in a sharp decrease in permeability and thus reducing the characteristic impedance of the transmission line. When this characteristic impedance is designed to match the load impedance (typically 50Ω), the main pulse can be transmitted to the load with low reflection.

[0035] The prepulse, as a low-amplitude non-zero signal preceding the main pulse, is insufficient to significantly alter the magnetization state of the ferrite. Under the influence of the axial bias magnetic field, the ferrite maintains a high permeability, causing the transmission line to exhibit a high characteristic impedance, resulting in a severe mismatch with the input source impedance. Most of the prepulse voltage is reflected back to the source. The voltage reflection coefficient at the interface between the source and the first magnetic transmission line 100 is given by the following formula: ; In the formula, The characteristic impedance when the prepulse enters the first magnetic transmission line 100. The input source impedance is L1. A reflection coefficient close to +1 indicates that the prepulse is strongly reflected, with only a very small portion entering L1 and propagating along the dispersive loss line, further attenuating before reaching the load. The combined effect of reflection and internal attenuation results in an extremely low prepulse amplitude observed at the load. Therefore, L1 acts as a nonlinear impedance filter: presenting a high impedance barrier to suppress reflection of the prepulse and a matched impedance to the main pulse for efficient transmission. The axial bias magnetic field provides precise control over the initial permeability, thereby adjusting the prepulse suppression level through the reflection coefficient.

[0036] Distributed capacitance of the first magnetic transmission line 100 and distributed inductance The following relationship must be satisfied: ; in, Represents the permeability of free space. Represents the vacuum permittivity. and It is the relative permeability of the insulating medium and the magnetic ring. and This represents the relative permittivity of the insulating medium and the magnetic ring. and These are the inner and outer radii of the ferrite ring. It is the inner diameter of the outer conductor.

[0037] The second magnetic transmission line 200 is used to achieve falling edge truncation, and its terminal is short-circuited. Utilizing the volt-second integral characteristic of the magnetic core, when the volt-second integral accumulated on the magnetic core by the pulse voltage reaches the saturation threshold, the magnetic core abruptly changes from a high permeability state to a saturated state, forming a low-impedance path, short-circuiting the pulse tail to ground, thereby obtaining a fast falling edge.

[0038] Core saturation trigger time The following relationship must be satisfied: ; In the formula, It is applying voltage. It is the number of turns in the winding. It is the effective cross-sectional area of ​​the magnetic core. This represents the magnetic flux density swing.

[0039] The structural parameters of the second magnetic transmission line 200 are optimized based on the required volt-second capacity and grounding capacitance. Its grounding capacitance... Determined by the following formula: ; in, This represents the length of the central conductor; the other symbols have the same meaning as above.

[0040] Based on the above embodiments, the actual working process of the high-voltage nanosecond pulse shaping device based on magnetic devices of the present invention is as follows: First, the initial pulse source 300 is connected to the parallel input terminals of the first magnetic transmission line 100 and the second magnetic transmission line 200. The load terminal 400 is connected to the output terminal of the first magnetic transmission line 100, and the output terminal of the second magnetic transmission line 200 is kept short-circuited to ground. In this embodiment, the initial pulse source 300 is a pulse generator based on a semiconductor circuit breaker SOS, and the output waveform is as follows. Figure 5As shown in the upper curve, its output original pulse amplitude is 25.6kV, rise time is 5.86ns, fall time is 7.7ns, bottom width is 34.6ns, pre-pulse oscillation is 8.98%, and tail oscillation is 5.96%.

[0041] The initial pulse synchronously enters the first magnetic transmission line 100 and the second magnetic transmission line 200. In the first magnetic transmission line 100, the pre-pulse, due to its small amplitude, cannot saturate the magnetic ring and exhibits high impedance under the influence of the bias magnetic field, thus being strongly suppressed by reflection. The main pulse rapidly saturates the magnetic ring, matching its characteristic impedance to a 50Ω load, achieving low-loss transmission, while continuously compressing and sharpening the rising edge. In the second magnetic transmission line 200, the pulse voltage is continuously applied to the magnetic ring, and the volt-second integral continuously accumulates. When the saturation threshold is reached, the magnetic ring rapidly saturates, and the second magnetic transmission line 200 changes from a high-impedance path to a low-impedance path, quickly short-circuiting the pulse tail to ground, achieving a steep falling edge and oscillation suppression.

[0042] In this embodiment, under the optimized condition of an axial bias magnetic field of 7 kA / m, such as Figure 5 As shown in the lower curve, the final output pulse waveform of the device is as follows: voltage amplitude 24kV, rise time 2.27ns, fall time 2.17ns, pulse width 6.78ns, pre-pulse oscillation amplitude ratio 0.99%, and tail oscillation amplitude ratio 2.57%. Compared with the original pulse, the rise and fall edges are significantly steeper, the pulse width is greatly compressed, and the pre-pulse and tail oscillations are greatly suppressed, which can meet the stringent waveform quality requirements of applications such as advanced light sources, plasma processing, and biomedical electroporation.

[0043] The pulse waveform shaped by this invention has extremely high purity, such as... Figure 4 As shown, typical simulation results indicate that the input pulse amplitude is 30kV, rise time is 4.8ns, fall time is 10.2ns, pulse width is 17ns, and prepulse amplitude is 26%. Figure 4 (Upper curve); After L1 and L2 integrated shaping, the output pulse amplitude is 29.8kV, rise time is 1.7ns, fall time is 3.7ns, bottom width is 5.9ns, and pre-pulse oscillation is <0.5% ( Figure 4 (Lower curve).

[0044] Based on the above embodiments, the present invention also provides a high-voltage nanosecond pulse shaping method based on magnetic devices. This high-voltage nanosecond pulse shaping method based on magnetic devices is applied to the high-voltage nanosecond pulse shaping device based on magnetic devices in the above embodiments, such as... Figure 7 As shown, the high-voltage nanosecond pulse shaping method based on magnetic devices specifically includes: S10. Energize the magnetic field coil of the first magnetic transmission line to generate an axial bias magnetic field inside the first magnetic transmission line. S20. The initial high-voltage nanosecond pulse is simultaneously fed into the first magnetic transmission line and the second magnetic transmission line. S30. The pre-pulse is suppressed by the high resistance state of the first magnetic transmission line, and the rising edge of the pulse is compressed by the damped gyromagnetic precession of the first magnetic ring moment in the first magnetic transmission line. S40. The second magnetic ring in the second magnetic transmission line reaches the volt-second integral saturation threshold, generating a fast falling edge and suppressing pulse tail oscillation. S50, the pulse continues to propagate within the first magnetic transmission line and the rising edge is further sharpened. The second magnetic transmission line saturates and truncates the pulse tail through the second magnetic ring, and the shaped pulse is applied to the load terminal.

[0045] In the above method, step S10 precisely controls the strength of the axial bias magnetic field by adjusting the magnitude of the DC current in the magnetic field coil, thereby adjusting the initial permeability of the first magnetic ring. For example, when it is necessary to enhance the suppression effect on the pre-pulse, the bias magnetic field can be appropriately increased, making it easier for the first magnetic ring to maintain a high permeability state under the action of the pre-pulse, thus exhibiting a higher characteristic impedance, increasing the reflection coefficient Γ, and reflecting more pre-pulse energy back to the source end.

[0046] In step S30, the damped precession of the magnetic moment of the first magnetic ring is the key physical process for achieving rising edge compression. When the leading current of the main pulse passes through the first central conductor, an alternating magnetic field is generated within the first magnetic ring. This alternating magnetic field, together with the axial bias magnetic field, drives the magnetic moment to precess. Due to the damping of the magnetic moment precession, its response speed is extremely fast, causing the permeability of the magnetic ring to decrease rapidly with the rapid change of current. This results in the characteristic impedance of the first magnetic transmission line decreasing rapidly to match the load impedance. This dynamic matching process effectively compresses the pulse rise time.

[0047] In step S40, the volt-second integral saturation threshold of the second magnetic ring is determined by its material properties (such as saturation magnetic induction), geometric parameters (such as effective cross-sectional area and number of turns), and the time integral of the applied voltage. When the integral of the pulse voltage on the second magnetic ring reaches this threshold, the magnetic flux density within the ring reaches saturation, the permeability drops sharply, and the characteristic impedance of the second magnetic transmission line decreases rapidly. This is equivalent to short-circuiting the pulse transmission path, allowing the energy at the pulse tail to be rapidly released, thus forming a steep falling edge and effectively suppressing any possible oscillations at the tail.

[0048] In step S50, the rising edge, initially sharpened by the first magnetic transmission line, is further optimized during its continued transmission due to the nonlinear characteristics of the magnetic ring material and the structural design of the transmission line, ensuring that the final pulse rising edge reaching the load is sufficiently steep. Simultaneously, after the second magnetic transmission line completes the falling edge truncation, its low impedance state persists for a period of time to ensure that the pulse tail is sufficiently suppressed, preventing residual oscillations from adversely affecting the load. The entire shaping method, through the coordinated work of the first and second magnetic transmission lines, achieves comprehensive optimization of pre-pulse suppression, rising edge sharpening, falling edge truncation, and tail oscillation suppression of the initial high-voltage nanosecond pulse, ultimately outputting a high-quality pulse waveform that meets specific application requirements.

[0049] Further, in step S10 above, energizing the magnetic field coil of the first magnetic transmission line to generate an axial bias magnetic field inside the first magnetic transmission line includes: S11. Adjust the current through the solenoid in the magnetic field coil to control the strength of the axial bias magnetic field so that the pre-pulse suppression degree and the rising edge sharpening degree are continuously adjustable.

[0050] In this embodiment, step S11 achieves continuous adjustment of the axial bias magnetic field within the range of 0 to 28 kA / m by changing the DC current input of the solenoid. For example, when stronger pre-pulse suppression is required, the solenoid current can be increased to enhance the axial bias magnetic field, making it more difficult for the first magnetic ring to saturate under the action of the pre-pulse, thereby maintaining a higher initial permeability and characteristic impedance, and improving the reflection effect of the pre-pulse. Conversely, when it is necessary to optimize the rising edge sharpening speed, the bias magnetic field can be appropriately reduced so that the main pulse current can drive the magnetic ring into saturation more quickly, accelerating the decrease in characteristic impedance and thus shortening the rise time. This current adjustment method provides the device with a flexible waveform optimization means, which can precisely adjust the shaping effect according to different initial pulse characteristics and application scenario requirements.

[0051] Further, in step S30 above, the high-resistivity suppression of the pre-pulse through the first magnetic transmission line and the damping of the gyromagnetic precession of the first magnetic ring moment within the first magnetic transmission line to compress the rising edge of the pulse includes: S31. Because the prepulse has a small amplitude, it cannot saturate the first magnetic ring. Under the action of the axial bias magnetic field, the first magnetic transmission line exhibits high impedance, causing the prepulse to be reflected and suppressed. S32. The main pulse rapidly saturates the first magnetic ring, and the characteristic impedance of the first magnetic transmission line matches the load terminal. The pulse leading edge is continuously compressed and sharpened.

[0052] In this embodiment, in step S31, the amplitude of the prepulse is typically much lower than that of the main pulse, and the magnetic field strength it generates is insufficient to overcome the effect of the axial bias magnetic field, causing a significant decrease in the permeability of the first magnetic ring. At this time, the characteristic impedance of the first magnetic transmission line is mainly determined by the high permeability ferrite material. According to the aforementioned formula, the characteristic impedance of the first magnetic transmission line is much greater than the input source impedance. Therefore, the reflection coefficient Γ≈+1, most of the energy of the prepulse is reflected back to the source end, and only a very small portion passes through the first magnetic transmission line. Furthermore, during propagation, it is further attenuated due to the inherent loss of the transmission line, thereby achieving effective suppression of the prepulse at the load end.

[0053] In step S32 above, when the leading current of the main pulse passes through the first central conductor, the strong alternating magnetic field it generates is superimposed on the axial bias magnetic field, causing the magnetic moment in the first magnetic ring to begin damped precession. As the current rapidly increases, the precession angle of the magnetic moment changes continuously, leading to a rapid decrease in permeability. When the permeability decreases to a level that matches the characteristic impedance of the first magnetic transmission line with the 50Ω impedance of the load terminal, the main pulse energy can be efficiently and with low reflection transmitted to the load. During this process, the dynamic change of permeability and the matching process of the characteristic impedance are continuous and rapid, thereby continuously compressing the rising edge of the main pulse and achieving a sharpening effect.

[0054] Further, in step S40 above, the second magnetic ring within the second magnetic transmission line reaching the volt-second integral saturation threshold, generating a fast falling edge and suppressing pulse tail oscillation includes: S41. The pulse voltage accumulates volt-second integral on the second magnetic ring. When the integral value reaches the saturation threshold, the second magnetic ring quickly saturates, making the second magnetic transmission line a low-impedance path and short-circuiting the pulse tail to ground. S42. After the second magnetic transmission line is short-circuited, a steep falling edge is formed and the tail oscillation is eliminated.

[0055] In this embodiment, in step S41, the short-circuit setting at the output end of the second magnetic transmission line allows the pulse voltage to be continuously applied to the second magnetic ring. According to the volt-second integral formula, as time goes by, the integral value of the voltage with respect to time accumulates continuously. When the integral value reaches the saturation threshold, the magnetic core of the second magnetic ring quickly changes from an unsaturated state with high permeability to a saturated state with low permeability. At this time, the characteristic impedance of the second magnetic transmission line is significantly reduced due to the sudden drop in the permeability of the magnetic ring, forming a low-impedance path, which is equivalent to short-circuiting the end of the pulse transmission path to ground.

[0056] In step S42, once the second magnetic transmission line forms a low-impedance path, the energy at the pulse tail is rapidly discharged to ground through this path. This process is extremely rapid, causing the voltage at the load end to drop from the pulse peak to near zero in a very short time, thus forming a steep falling edge. Simultaneously, because the pulse tail is directly short-circuited, the energy of tail oscillations that might have been caused by impedance mismatch or other parasitic parameters is effectively absorbed and discharged, preventing these oscillations from interfering with the load end and significantly improving the trailing edge quality and waveform stability of the output pulse.

[0057] Specifically, in one specific embodiment of the present invention, in conjunction with Figure 6 The schematic diagram of the pulse propagation and shaping process illustrates the high-voltage nanosecond pulse shaping method based on magnetic devices in detail: Figure 6 In the diagram, the horizontal axis z represents the spatial position of the pulse in the transmission line, the gray area is the effective range of the first magnetic transmission line (L1), the solid line is the actual shaped pulse waveform, and the dashed line is the original pulse waveform that has not been shaped.

[0058] like Figure 6 As shown in (a), the initial high-voltage nanosecond pulse has not yet entered the region of the first magnetic transmission line (L1). At this time, the pulse is in the original triangular wave shape, with relatively flat rising and falling edges, and there are pre-pulse interference and tail trailing problems.

[0059] like Figure 6 As shown in (b), the initial pulse begins to enter the region of the first magnetic transmission line (L1). Under the action of the axial bias magnetic field, the low-amplitude pre-pulse cannot saturate the first magnetic ring, and the first magnetic transmission line exhibits a high impedance state. The pre-pulse is suppressed by reflection, and the baseline on the left side of the pulse returns to zero level. At the same time, the main pulse causes the first magnetic ring to quickly enter the saturation state. Through the damping gyromagnetic precession effect of the magnetic moment of the magnetic ring, the rising edge of the pulse is initially compressed and sharpened, and the leading edge slope is significantly improved.

[0060] like Figure 6 As shown in (c), the pulse continues to propagate within the first magnetic transmission line (L1) region, the pre-pulse is further completely suppressed, the rising edge is continuously sharpened, and the leading edge becomes steeper, laying the foundation for subsequent narrow pulse width output.

[0061] like Figure 6 As shown in (d), when the pulse propagates to the second half of the region of the first magnetic transmission line (L1), the second magnetic ring in the second magnetic transmission line accumulates volt-second integrals to reach the saturation threshold, the magnetic ring quickly saturates, the second magnetic transmission line changes from high impedance to low impedance path, short-circuit the pulse tail to ground, the slow falling edge of the original pulse is forcibly cut off, forming a steep fast falling edge, and at the same time suppressing the tail oscillation.

[0062] like Figure 6As shown in (e), the pulse completely leaves the region of the first magnetic transmission line (L1) and is applied to the load terminal. The final output is a high-quality high-voltage nanosecond pulse with fast rise, fast fall, narrow pulse width, low pre-pulse and low tail oscillation. Compared with the original pulse, the waveform quality is fully optimized, which can meet the stringent requirements of pulse waveform in applications such as plasma industrial processing and biomedical electroporation.

[0063] In summary, this invention provides a high-voltage nanosecond pulse shaping device and method based on magnetic devices. The high-voltage nanosecond pulse shaping device includes: a first magnetic transmission line and a second magnetic transmission line; the input ends of the first and second magnetic transmission lines are connected in parallel and connected to an initial pulse source; the output end of the first magnetic transmission line is connected to a load terminal; the output end of the second magnetic transmission line is short-circuited to ground; the first magnetic transmission line includes a first magnetic ring disposed axially inside and a magnetic field coil disposed axially outside, used to sharpen the pulse rising edge and suppress pre-pulse reflection; the second magnetic transmission line includes a second magnetic ring disposed axially inside, used to truncate the pulse falling edge and suppress tail oscillation. This invention is based on the current-dependent nonlinear permeability effect of a magnetic ring. Through the rising sharpening effect of the first magnetic transmission line and the falling truncation effect of the second magnetic transmission line, it simultaneously achieves pulse rise time compression, fall time truncation, pulse width shortening, and suppression of pre-pulse and tail oscillation. This solves the problem that single nonlinear transmission line or magnetic switch technology can only optimize single pulse parameters. Finally, a high-quality pulse waveform with fast rise time, fast fall time, narrow pulse width, and low oscillation is obtained at the load terminal, so it can be applied to application scenarios with high pulse waveform quality requirements.

[0064] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A high-voltage nanosecond pulse shaping device based on magnetic devices, characterized in that, The high-voltage nanosecond pulse shaping device based on magnetic devices includes: A first magnetic transmission line and a second magnetic transmission line are connected in parallel at their input ends and connected to the initial pulse source; the output end of the first magnetic transmission line is connected to the load terminal; the output end of the second magnetic transmission line is short-circuited to ground. The first magnetic transmission line includes a first magnetic ring disposed axially inside and a magnetic field coil disposed on the outside, used to sharpen the rising edge of the pulse and suppress the reflection of the pre-pulse; The second magnetic transmission line includes a second magnetic ring disposed axially inside, used to achieve pulse falling edge truncation and tail oscillation suppression.

2. The high-voltage nanosecond pulse shaping device based on magnetic devices according to claim 1, characterized in that, The first magnetic transmission line includes a first central conductor, a first magnetic ring, and a first outer conductor that are coaxially arranged from the inside to the outside. The magnetic field coil is sleeved on the outside of the first outer conductor, and a first insulating medium is filled between the first magnetic ring and the first outer conductor. The second magnetic transmission line includes a second central conductor, a second magnetic ring, and a second outer conductor, which are coaxially arranged from the inside to the outside, with a second insulating medium filling the space between the second magnetic ring and the second outer conductor.

3. The high-voltage nanosecond pulse shaping device based on magnetic devices according to claim 2, characterized in that, The first insulating medium and the second insulating medium are respectively one of air, insulating oil, and polyethylene.

4. The high-voltage nanosecond pulse shaping device based on magnetic devices according to claim 2, characterized in that, The length of the first magnetic ring is greater than the length of the second magnetic ring; The first magnetic ring includes a plurality of first sub-magnetic rings; The second magnetic ring includes a plurality of second sub-magnetic rings, the second sub-magnetic rings having the same magnetic parameters as the first sub-magnetic ring; the diameter of the second sub-magnetic ring is larger than the diameter of the first sub-magnetic ring. Both the first and second sub-magnetic rings are Ni-Zn ferrite magnetic rings.

5. The high-voltage nanosecond pulse shaping device based on magnetic devices according to claim 2, characterized in that, The first center conductor and the second center conductor are both aluminum alloy cylinders, and the diameter of the first center conductor is smaller than the diameter of the second center conductor. The first outer conductor and the second outer conductor are both metal tubes, and the diameter of the first outer conductor is smaller than the diameter of the second outer conductor.

6. The high-voltage nanosecond pulse shaping device based on magnetic devices according to claim 1, characterized in that, The magnetic field coil includes an epoxy tube and a solenoid wound around the outside of the epoxy tube, and the current of the magnetic field coil can be adjusted.

7. A high-voltage nanosecond pulse shaping method based on magnetic devices, applied to the high-voltage nanosecond pulse shaping device based on magnetic devices described in any one of claims 1-6, characterized in that, The high-voltage nanosecond pulse shaping method based on magnetic devices includes: When the magnetic field coil of the first magnetic transmission line is energized, an axial bias magnetic field is generated inside the first magnetic transmission line. The initial high-voltage nanosecond pulse is simultaneously fed into the first magnetic transmission line and the second magnetic transmission line. The high-resistivity state of the first magnetic transmission line suppresses the prepulse, and the damped gyromagnetic precession of the first magnetic ring moment in the first magnetic transmission line compresses the rising edge of the pulse. The second magnetic ring within the second magnetic transmission line reaches the volt-second integral saturation threshold, generating a fast falling edge and suppressing pulse tail oscillation; The pulse continues to propagate within the first magnetic transmission line and the rising edge is further sharpened. The second magnetic transmission line saturates and truncates the pulse tail through the second magnetic ring, and the shaped pulse is applied to the load terminal.

8. The high-voltage nanosecond pulse shaping method based on magnetic devices according to claim 7, characterized in that, The step of energizing the magnetic field coil of the first magnetic transmission line to generate an axially biased magnetic field inside the first magnetic transmission line includes: The magnitude of the current passing through the solenoid in the magnetic field coil is adjusted to control the strength of the axial bias magnetic field, so that the pre-pulse suppression degree and the rising edge sharpening degree are continuously adjustable.

9. The high-voltage nanosecond pulse shaping method based on magnetic devices according to claim 7, characterized in that, The high-resistivity suppression prepulse via the first magnetic transmission line, and the pulse rising edge compressed by the damped gyromagnetic precession of the first magnetic ring moment within the first magnetic transmission line, includes: The prepulse is too small to saturate the first magnetic ring. Under the action of the axial bias magnetic field, the first magnetic transmission line exhibits high impedance, which causes the prepulse to be reflected and suppressed. The main pulse causes the first magnetic ring to saturate rapidly, the characteristic impedance of the first magnetic transmission line is matched with the load termination, and the pulse leading edge is continuously compressed and sharpened.

10. The high-voltage nanosecond pulse shaping method based on magnetic devices according to claim 7, characterized in that, The second magnetic ring within the second magnetic transmission line reaches the volt-second integral saturation threshold, generating a fast falling edge and suppressing pulse tail oscillations, including: The pulse voltage accumulates volt-second integrals on the second magnetic ring. When the integral value reaches the saturation threshold, the second magnetic ring quickly saturates, making the second magnetic transmission line a low-impedance path and short-circuiting the pulse tail to ground. The second magnetic transmission line forms a steep falling edge after being short-circuited, thus eliminating tail oscillations.

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