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A long-pulse generator TPG700L based on a Tesla transformer and a series pulse forming network (PFN) is constructed to generate intense electron beams for the purpose of high power microwave (HPM) generation. The TPG700L mainly consists of a 12-stage PFN, a built-in Tesla transformer in a pulse forming line, a three-electrode gas switch, a transmis...
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This paper puts forward a generalization of the multisynchrosqueezing transform (MSST) using the second order local estimate of instantaneous frequency, which could localize a signal with high precision both in time and frequency. Numerical signal simulation result verifies its advantage on processing high power microwave (HPM) signals in different...
Citations
... The typical generators of this kind can be found in Refs. [12][13][14]. ...
The concept of the coaxial cascade-line rectangular-pulse generator is put forward, the basic idea of which is to cascade two coaxial lines of equal impedance together and make one line turn around to let the two lines use a common middle tube. The obvious feature of this kind of generator is that it can form a rectangular pulse with a width of 4 times the electrical length of one line. Compared with the conventional single-tube generator, the total stored energy is doubled. Namely, the output pulse width of the coaxial cascade-line generator is doubled for the same output voltage, which is beneficial for miniaturization. The principle of the cascade pulse forming line is first introduced; then the coaxial cascade-line rectangular-pulse generator is suggested. The simulation results prove the feasibility of the cascade-line generators. Finally, the design of a Tesla-type generator with an output power of 20 GW and a pulse width of 40 ns is presented based on the coaxial cascade-line method.
Published by the American Physical Society 2025
... As energy sources, the following can be used: Tesla transformers [5], SOS diodes (a type of semiconductor diode made using silicon deposited on a sapphire substrate, providing high electrical insulation and improved characteristics in high-frequency modes), Marx generators [6], plasma current switches [7][8][9][10][11]. ...
The energy and design parameters of some vircator systems are considered. Calculated cutoff frequencies for the main E and H modes of the DIN-2K accelerator waveguides with electron beam parameters: ~ 15 kA and ~ 185 kV. The characteristic frequencies of oscillations of the virtual cathode depending on the distance of the anode-cathode gap were calculated. Experimentally obtained amplitude-frequency spectra (up to 6 GHz) in the far zone of electromagnetic radiation (Fraunhofer zone) for a horn antenna.
... [15][16][17][18][19][20][21][22][23][24] As for the Tesla-type generator, the coaxial transmission line connected to the Tesla transformer is replaced by multi-stage series PFN/PFL units to form a mixed PFL, whose size and weight are reduced. [25][26][27][28] There have been fruitful studies on the optimized design of PFN. For example, Guillemin networks with various configurations are widely used to achieve high quality quasi-square pulses. ...
... The peak-to-peak value of oscillation at the flat top of the voltage pulse is about 6%. Compared to the pulse waveforms generated by the mixed PFL with capacitor-loaded PFN, 26,28 the oscillation of the flat top is reduced. ...
The miniaturization, lightweight, and solidification of pulse forming lines (PFLs) are of prime significance during the evolution of pulsed power technology. In this paper, an all-solid-state annular pulse forming line (APFL) based on film-insulated coaxial transmission lines is developed to generate fast-rise time quasi-square pulses. First, a coiled coaxial transmission line (CCTL) comprised of multilayer polypropylene films with outstanding insulating properties is constructed. It can withstand direct current voltages up to 200 kV, with a cross section diameter of 7.4 mm. In addition, in order to turn the pulse transmission direction from circumferential to axial, a compact insulated terminal with a 90° bend structure is designed for CCTL. Although single terminal inductance can slow down the rising edge of the output pulse, their parallel connection in an APFL can weaken such an effect. The APFL, with a characteristic impedance of 2.95 Ω and a transmission time of 13 ns, is composed of three CCTLs with six terminals, which can run over 100 thousand times under the pulse voltage of 75 kV. Finally, 15 series APFL modules are employed to assemble a multi-stage PFL for the Tesla-type pulse generator. When charged to a voltage of 1 MV, the mixed PFL consisting of a coaxial line and the multi-stage PFL outputs quasi-square pulses with a voltage amplitude, rise time, and width of 510 kV, 4 ns, and 41.5 ns, respectively, and the fluctuation of the flat top is about 6%.
... Pulsed power technology, from 1960s, intends to compress power into mega-or gigawatts and output to the loads [1]- [3]. This technology is not an alternative to traditional AC or DC power engineering. ...
... Among these generators, the TPG series, which was constructed in the Northwest Institute of Nuclear Technology (NINT), has different features. For example, the TPG2000 can output a pulse with a power as great as 40 GW [2]; the TPG700L can output a pulse with a width as long as 200 ns [3]; and the TPG400 can be used for research of vacuum breakdown under both nanosecond and mi-crosecond pulses [4]. Figure 1 shows a photo of the TPG700L and its output waveform. ...
This article summarizes the recent developments in insulation research under short-pulse conditions in the Northwest Institute of Nuclear Technology in China, which include four aspects: (1) solid insulation under nanosecond pulses, (2) vacuum insulation under microsecond pulses, (3) insulation design methods, and (4) long-lifetime insulation structures.
... T HE Tesla transformer comprises two relevant induction loops, which work in free resonant states and have equivalent intrinsic frequency. Open-magnetic-core Tesla transformers are widely used as repetitive high power microwave (HPM) generators due to their high coupling coefficient (k) [1], [2], [3], [4], [5], [6], [7], [8]. Different series of Tesla-type generators with open-magnetic cores were constructed. ...
... The increase of R sp of the coppertitanium-composite primary leads to the increase of R. Then the increase of R in turn leads to the decrease of λ 0 and η. Table V compares the theoretical λ 0 and η for a pure copper primary winding with those of a composite winding with (3) and (4). From this table, it is seen that λ 0 is decreased by 1.5% and η is decreased by 2.6%. ...
A copper-titanium-composite primary winding for Tesla transformer is proposed in order to enhance its mechanical strength. This winding comprises a thin copper board and a thin titanium board which are joined by vacuum brazing welding. The copper board is specially used to conduct the current, while the titanium board is specially used to enhance the mechanical strength. A copper-titanium-composite primary winding with an axial length of 1 m, a diameter of 0.6 m, and a total thickness of 0.6 mm was designed, fabricated, assembled, and tested in an open-magnetic-core Tesla transformer, which realizes a normalized voltage boosting factor of 0.865 and an energy transfer efficiency of 0.712.
... Due to its importance, a great effort has been undertaken to improve the main characteristics of the closing switch such as jitter, lifetime, operating voltage, and weight. Different types of switches have been developed, such as the single gas-gap switch [7,8], the trigatron switch [9][10][11], the V/N switch (voltage-division number) [12][13][14], the corona-triggered switch [15][16][17], and the radial switch [18,19]. ...
... For example, the single gas-gap switch can conduct a high current up to hundreds of kilo amperes (kA), but the repetition rate is limited and the jitter can be relatively large [7,8]. The trigatron switch, designed with a needle-like electrode placed in the center of the low-voltage (LV) electrode of the gas gap to initiate the breakdown, can partially solve the problem of jitter [9][10][11]. In order to increase the repetition rate and further lower the jitter of the single gas-gap switch, the V/N switch and the corona switch were developed, the former using the technology of the LC circuit (inductance and capacitor) to revert the voltage to realize trigger [12][13][14] and the latter using the technology of corona discharge to initiate and stabilize the discharge [15][16][17]. ...
The paper presents the development of a megavolt-class SF6-insulated radial switch. The switch is used as a crowbar in a MV Tesla-type generator to produce pulsed electric fields in very large volumes, for proof-of-concept experimentation of a novel non-invasive food processing technology. The main features of the switch include: (1) Using SF6 gas as the insulation gas; (2) a breakdown channel along the radial direction, rather than axial; (3) a compact configuration with its volume limited to 3.2 L. In order to achieve a ruggedized high voltage insulation as well as an enhanced operation safety, the following design techniques were applied: (1) Structures of the switch were well designed to minimize the local electric filed in the cathode triple junctions; (2) the grooves of surface of the insulators that enclose the switch were finely optimized to keep the surface flashover under control; (3) a prolate spheroid geometry of the high voltage electrode was adopted to achieve a better control of the gas breakdown. This paper describes in detail the design and the preliminary test of this switch.
... The Tesla-type generator uses a Tesla transformer as its main voltage-boosting unit. [1][2][3][4][5] It consists of two induction loops that operate in free resonant states and have equivalent intrinsic frequencies. A notable feature of the Tesla transformer is that it has a coefficient, k, with values such as 1, 0.6, 0.385, and 0.28. ...
... The former has the advantage of easy construction [6][7][8][9] but the disadvantage of not being suitable for working in repetition states since it only operates in dual-resonance (or triple resonance), in which the maximum high voltage (HV) appears in the second reverse peak and the switch may not function properly; whereas the latter (having k < 1) has the major advantage of generating the peak voltage during the first half period, producing conditions for the HV switch to operate perfectly for a repetition state by embedding magnetic cores into the coaxial pulse forming line (PFL). [1][2][3][4][5] Intensive research on generators has been conducted at the Northwest Institute of Nuclear Technology in China since 2000. The transformers in them are designed to have equivalent resonant frequencies, because of which they are classed as Tesla transformers. ...
... A series of Tesla-type pulsed power generators, i.e., TPG (Tesla-pulsed generator)-series generators with magnetic cores embedded in the pulse-forming line, have been developed at our institute. [1][2][3][4][5]21,26 Their values of λ 0 are usually in the range of 0.75-0.90. The MWL secondary winding used here had 2000 turns. ...
A compact multi-wire-layered secondary winding for the Tesla transformer was proposed by Zhao et al. [Rev. Sci. Instrum. 88(5), 055112 (2017)]. The basic idea is to wind multiple layers of a metal wire around a polymeric base tube. However, the lifetime of this type of winding is only about 200 000 pulses, and thus it fails to meet the requirement of a lifetime of 1 × 10 ⁶ pulses. In this study, two methods are developed to prolong the lifetime of this winding. One method involves replacing the original three-skin wire with a polytetrafluoroethylene (PTFE) wire. The results of small-scale experiments in different conditions show that the lifetime of the PTFE-covered copper wire is at least ten times longer than that of the three-skin wire. The other method involves improving the local structure of this winding. A strong mechanical stress is concentrated at the small end of the winding, and a highly intense electric field appears in this region, where both reduce the lifetime of the winding. Improving the local structure of the winding theoretically prolongs its lifetime by a factor of 4. Both methods were applied to the original secondary winding of a Tesla transformer and extended its theoretical lifetime by a factor of 40. The modified winding had a lifetime longer than 2 × 10 ⁶ pulses without any traces of discharge. This is equivalent to a lifetime longer than that of the original winding by a factor of 10 and verifies the effectiveness of the proposed methods.
... The past decade has seen various custom-built HPM drivers around the world, using very different technical approaches [12][13][14][15][16][17][18][19][20][21][22], with peak power ranging from several to several tens of gigawatts. Most of the drivers have a water or oil filled coaxial or Blumlein pulse forming lines (PFL). ...
... For lower impedance (<20 Ω) requirements, water or aqueous based liquid mixture may be used as they have a higher dielectric constant than transformer oil [22,24]. Some other accelerators have no pulse forming lines, as they use a Marx generator or a linear transformer driver (LTD) with a very short rise time [14,15,21] or with a pulse forming network (PFN) [19,20], and the output pulse width is not limited by the geometry length of the driver. These PFLless drivers are also aimed at driving the high impedance HPM loads and they have much more components than drivers with pulse forming lines. ...
A low impedance high power microwave (HPM) driver is designed, which can be used in studying multi-gigawatt HPM devices such as the magnetically insulated transmission line oscillator (MILO), based on a helical pulse forming line (PFL) and the Tesla pulse transformer technology. The co-axial PFL is insulated by ethanol–water mixture, whose dielectric constant can be adjusted; and the helical line increases the output pulse width as well as the impedance to make a better match with the load. By the optimal combination of PFL charging voltage and output switch working voltage, the reliability of the PFL can be improved. The Tesla transformer has partial magnetic cores to increase the coupling coefficient and is connected like an autotransformer to increase the voltage step-up ratio. The primary capacitor of the transformer is charged by a high voltage constant current power supply and discharged by a triggered switch. A transmission line is installed between the PFL and the HPM load, to further increase the load voltage. A ceramic disk vacuum interface is used for improving the vacuum of the HPM tube. The experiments show that the driver can operate at 30 GW peak power, 75 ns pulse width and 5 Hz repetition rate.
... However, its energy density 14,15 is less than 1 J/L. In Ref. 7, PFN units were connected in series to improve the energy storage capacity, but the working voltage would be very high (about 1.2 MV), and more free space would be needed to avoid breakdown, whereby the energy density is reduced (0.75 J/L). Pulse forming modules based on semiconductor technology could also realize the solid-state form and the GW level of power. ...
... Owing to the above two reasons, the energy density of the Blumlein-type PFN is higher than that of other PFN types. [5][6][7]14,15 Furthermore, since the compact structure results in stronger electromagnetic coupling, stray inductance becomes more complicated, thereby affecting the performance of pulse modulation devices, especially low impedance devices. To overcome this problem, a double switch modulation circuit is employed in this paper. ...
A pulse forming network (PFN) has the advantages of compactness and long pulse achievability, which could meet the requirements of military and industrial applications of pulsed power technology well. In this paper, a compact low impedance Blumlein-type PFN based on ceramic capacitors is investigated numerically and experimentally. Generally, in order to increase the compactness of the PFN, an angular distribution and an axially parallel connected structure with a theoretical peak energy density of up to 5.8 J/L are employed. The dimensions of the PFN are Φ 560 × 345 mm². A sharpening switch, which can efficiently reduce rise-time of the output pulses, is utilized to improve the performance of the PFN. The compact low impedance Blumlein-type PFN was assembled in our laboratory. The results of low voltage experiments show that the PFN could generate quasi-square pulses with an output power of 50 MW and a peak voltage of approximately 13.2 kV on a matched dummy load. Impedance and output pulse duration of the PFN are 3 Ω and 135 ns, respectively. The results of high voltage experiments show that pulses with a power of about 1 GW and an energy density of about 2.5 J/L were obtained. Experiments show reasonable agreement with numerical analysis.
... Under the circumstance of intensive EM radiation from the pulse driver itself, the instantaneous conducting disturbances are difficult to be observed. In order to accurately test the instantaneous communication disturbances on the four communication lines in full time domain, a shielded transition cable is employed and four extra test lines (1,2,3,4) are lead out at the side of SB. As shown in Fig. 2b, an isolated and shielded oscilloscope and a differential voltage probe are used to test the instantaneous conducting disturbance signals between the four communication lines, or between any communication line and the ground. ...
... The key point is to compare ΔT 0 with (1/m) − ΔT i and T − n/m, in order to accurately calculate P. Under the m Hz/n pulses work mode, the maximum resonant probability P in T is calculated as (2). ...
... In our Tesla pulse driver system, the communication signal between the battery and the CMC had the work parameters such as T = 5 s, m = 50 Hz, n = 1000 and ΔT 0 = 0.1 s. In view of that mT < n and ΔT 0 >(1/m) − ΔT i , the resonant probability is calculated as P = 1 according to (2). From (1), the resonant probability P 0 under the single shot mode can also be calculated as Table 2. ...
The communication circuit network is widely employed for signal transmission in high‐voltage pulse driver system, for commanding, controlling, measurement & communication. The electromagnetic compatibility of the communication circuit network mainly decides the stability and reliability of the high‐voltage pulse driver system. Aiming at the electromagnetic interference (EMI) problems of the RS422 communication circuit in the Tesla pulse driver, the generated disturbance sources and characteristics from the Tesla pulse driver itself are analysed in five divided work stages, and two typical simplified EMI coupling modes for the communication circuit are also presented in this Letter. In the RS422 communication cable circuits between the subsystems of the pulse driver, the time‐domain resonant characteristics of the communication signal and the conducting disturbances are analysed. The error and failure modes of the RS422 communication data caused by the full time‐domain conducting interference are also revealed. Evaluation and calculation method for the time‐domain resonant probability and the interference probability of the RS422 communication signals is also put forward. The communication interference probability is also calculated under different repetition work modes of the Tesla pulse driver. In view of the time‐domain resonance phenomenon, some effective ways for time‐domain resonance elimination and interference compression are put forward.
