A high precision laser trigger system is built up in the single test module of Primary Test Stand （PTS） facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd：YAG laser was used to trigger the 5 ...A high precision laser trigger system is built up in the single test module of Primary Test Stand （PTS） facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd：YAG laser was used to trigger the 5 MV multi-gap multi-channel gas switch which was filled with high pressure SF6-N2 mixture gas. The maximum deviation and the standard deviation in the jitter time of the trigger system is 4- 0.7 ns and 0.3 ns respectively. The maximum deviation and the standard deviation in the jitter time for the multi-gap multi-channel laser triggering switch is 4- 2.4 ns and 1.5 ns respectively. The curve of switch delay-time versus laser energy is obtained, which is helpful for the choice of fitting laser energy. The successful test with two lasers indicated that the design of using twenty-four lasers to trigger twenty-four switches respectively is feasible in ＂PTS＂.展开更多
Triggered spark-gap switch is a popular discharge switch for pulse power systems.Previous studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in...Triggered spark-gap switch is a popular discharge switch for pulse power systems.Previous studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in the systems.Such switches are one-shot due to electrodes being too thin to sufficiently resist spark-erosion.Additionally,these switches did not employ any structures in securing internal gas composition,resulting in inconsistent performance under harsh atmospheres.In this work,a novel planar triggered spark-gap switch(PTS)with a hermetically sealed cavity was batched-prepared with printed circuit board(PCB)technology,to achieve reusability with low cost.The proposed PTS was inspected by micro-computed tomography to ensure PCB techniques meet the requirements of machining precision.The results from electrical experiments demonstrated that PCB PTS were consistent and reusable with lifespan over 20 times.The calculated switch voltage and circuit current were consistent with those derived from real-world measurements.Finally,PCB PTS was used to introduce hexanitrostilbene(HNS)pellets in a pulse power system to verify its performance.展开更多
Triggering characteristics of triggered vacuum switch （TVS）, including the discharge delay time, delay jitter, range of operational voltage and peak of pulsed current, are investigated. Both structure and experiment...Triggering characteristics of triggered vacuum switch （TVS）, including the discharge delay time, delay jitter, range of operational voltage and peak of pulsed current, are investigated. Both structure and experimental circuit of TVS are presented. The results indicate that TVS, as a surface flashover triggering device with high dielectric permittivity material, is with excellent triggering characteristics. When the hold-off voltage reaches 120 kV, the minimum operational voltage is 1.3 kV, and the minimum discharge delay time and jitter are 100 ns and ±10 ns, respectively. The peak current is up to 240 kA when the operational voltage reaches 100 kV. TVS can well satisfy the main demands of high voltage and current applications, and can also be used under a multi-crowbar circuit.展开更多
A trigger device and a triggered pseudospark switch （TPSS） were designed based on surface flashover technology, in order to meet the requirements from present pulse power technology and pulse current test technology...A trigger device and a triggered pseudospark switch （TPSS） were designed based on surface flashover technology, in order to meet the requirements from present pulse power technology and pulse current test technology such as a long lifetime, reliability in a wide voltage range, a short delay time, as well as small delay jitters. The trigger devices were made from different dielectric materials, with their permittivities from tens to thousands. The trigger characteristics of TPSS were investigated. The results indicate that the high-dielectric trigger device shows better performance and higher emitted charge of the electron emission within all adjusted parameters including the gas pressure and applied voltage. For the dielectric material with relative permittivity εr of 3460, when the gas pressure is 7 Pa, the hold-off voltage of TPSS is 28 kV, the minimum trigger switch voltage drops to 128 V, the minimum discharging delay time and delay jitter are less than 35ns and 6ns, respectively, and the reliable operation can be reached within a very large range of charging voltage, between 0.46% and 99% of its self-breakdown voltage.展开更多
A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Fie...A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Field distribution in the switch section is regulated by a metal field regulation ring and several gradient rings. In order to reduce the jitter further, a SFB/N2 mixture is chosen as the switching medium. The generalized standard deviation of the self-breakdown voltage and the deviation of the average value from the prediction is less than 4.4% and 13% respectively. Linearity of the self-breakdown voltage is better than 0.95. Triggered by a laser pulse of 35 mJ/3 ns, the delay is about 26 ns at a working voltage of 85±3% USB （Self-breakdown Voltage）. Maximum deviation of delay is less than =t=2.5 ns. Jitter is less than 1.5 ns. The delay and jitter decrease with the increase in the working ratio （the ratio of working voltage to USB）, pressure or voltage.展开更多
Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of th...Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of the FLTD. In this paper, the breakdown characteristics of the trigger gap and the overvoltage gap are studied experimentally. The reasons for the different breakdown performance of the two gaps are also investigated. The results show that the breakdown delay of the trigger gap is more influenced by the trigger voltage, while the breakdown delay of the overvoltage gap is more influenced by the working coefficient and always higher than that of the trigger gap. The jitter of the trigger gap is more influenced by the trigger voltage and accounts more than 60% of the total switch jitter, while the jitter of the overvoltage gap is hardly changed with the trigger voltage as well as the working coefficient and maintains less than 1.4 ns. It is proved that the discharging product from the trigger gap can effectively reduce the breakdown delay and jitter of the overvoltage gap. Based on that, the effect and improvement of pre-ionization on the two gaps are also studied. It is concluded that the jitter of the trigger gap reduces obviously when the pre-ionization is added, while the pre-ionization almost has no effect on the jitter of the overvoltage gap. The jitter of the overvoltage gap is about two times higher than the trigger gap in the pre-ionizing switch.展开更多
The characteristics of the triggered vacuum switch （TVS） are obviously influenced by the emission current ie and emission charge of the trigger device. In this paper, an RC charge collector is designed, and the char...The characteristics of the triggered vacuum switch （TVS） are obviously influenced by the emission current ie and emission charge of the trigger device. In this paper, an RC charge collector is designed, and the characteristics of emission current ie and collecting charge Qc of the trigger device are studied. The experimental results indicate that the emission current ie which is produced by the initial plasma has both positive and negative components, and the polarity of the emission current ie depends mainly on the polarity of the bias voltage UBias. The emission current ie and collecting charge Qe increase with the increase of the trigger voltage Utr and the bias voltage UBias. The emission efficient r] increases linearly with the increase of the bias voltage UBias. When the gap distance is 15 mm and bias voltage UBias is 160 V and trigger voltage Utr is 2.6 kV, the emission efficiency r/reaches 6%展开更多
This paper investigates the time-varying formation problem for general linear multi-agent systems using distributed event-triggered control strategy.Different from the previous works,to achieve the desired time-varyin...This paper investigates the time-varying formation problem for general linear multi-agent systems using distributed event-triggered control strategy.Different from the previous works,to achieve the desired time-varying formation,a distributed control scheme is designed in an event-triggered way,in which for each agent the controller is triggered only at its own event times.The interaction topology among agents is assumed to be switching.The common Lyapunov function as well as Riccati inequality is applied to solve the time-varying formation problem.Moreover,the Zeno behavior of triggering time sequences can be excluded for each agent.Finally,a simulation example is presented to illustrate the effectiveness of the theoretical results.展开更多
We propose a new approach to discuss the consensus problem of multi-agent systems with time-varying delayed control inputs, switching topologies, and stochastic cyber-attacks under hybrid-triggered mechanism.A Bernoul...We propose a new approach to discuss the consensus problem of multi-agent systems with time-varying delayed control inputs, switching topologies, and stochastic cyber-attacks under hybrid-triggered mechanism.A Bernoulli variable is used to describe the hybrid-triggered scheme, which is introduced to alleviate the burden of the network.The mathematical model of the closed-loop control system is established by taking the influences of time-varying delayed control inputs,switching topologies, and stochastic cyber-attacks into account under the hybrid-triggered scheme.A theorem as the main result is given to make the system consistent based on the theory of Lyapunov stability and linear matrix inequality.Markov jumps with uncertain rates of transitions are applied to describe the switch of topologies.Finally, a simulation example demonstrates the feasibility of the theory in this paper.展开更多
Pseudo-spark switch（PSS） is one of the most widely used discharge switches for pulse power technology.It has many special characteristics such as reliability in a wide voltage range,small delay time,as well as small...Pseudo-spark switch（PSS） is one of the most widely used discharge switches for pulse power technology.It has many special characteristics such as reliability in a wide voltage range,small delay time,as well as small delay jitter.In this paper,the measuring method for the initial plasma of ZnO surface flashover triggering device of PSS is studied and the results of the measurement show that the electron emission charge is mainly influenced by trigger voltage,gas pressure and DC bias voltage.When the bias voltage increases from 2 kV to 6 kV with the gap distancc fixed at 3 mm,the electron emission charge changes from 2 μC to about 6μC.When the gap distance changes from 3 mm to 5 mm with the bias voltage fixed at 2 kV,the electron emission charge increases from 1.5 μC to 2.5μC.When the gap distance is 4 mm,the hold-off voltage of PSS is 45 kV at gas pressure of 2 Pa,the minimum operating voltage is less than 1 kV.So,the operating scope is from 2.22%to 99%of its self-breakdown voltage.The discharging delay time decreases from 450 ns to 150 ns when the trigger pulse voltage is 1 kV and the discharging voltage is changed from 1 kV to 12 kV.When the trigger pulse voltage is 6 kV,the discharging delay time is less than 100 ns and changes from 100 ns to 50 ns,and the delay jitters are less than30 ns.展开更多
Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed conve...Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.展开更多
Accurate and reliable triggering is one of the most important issues with high power pseudospark switch, because it not only has an impact on the design of discharge chamber of switch, but also has an influence on the...Accurate and reliable triggering is one of the most important issues with high power pseudospark switch, because it not only has an impact on the design of discharge chamber of switch, but also has an influence on the dynamic range of operation voltage, repetition frequencies and lifetime of switch. The unique feature of pseudospark switch is its hollow cathode geometry. The hollow cathode effect produced by the hollow cathode provides the protection of the switch for the triggering unit from erosion by high discharge plasma. In this paper, a zinc oxide (ZnO) surface flashover triggering is presented. This trigger unit possesses an excellent time delay (80 ns - 360 ns) and jitter (20 ns - 50 ns) at the switch voltage of 30 kV - 2 kV. The emitted plasma electron density is high enough to trigger switch reliably down to switch voltage of 440 V.展开更多
This paper investigates the problem of event-triggered finite-time <i>H</i><sub>∞</sub> control for a class of switched stochastic systems. The main objective of this study is to design an eve...This paper investigates the problem of event-triggered finite-time <i>H</i><sub>∞</sub> control for a class of switched stochastic systems. The main objective of this study is to design an event-triggered state feedback <i>H</i><sub>∞</sub> controller such that the resulting closed-loop system is finite-time bounded and satisfies a prescribed <i>H</i><sub>∞</sub> level in some given finite-time interval. Based on stochastic differential equations theory and average dwell time approach, sufficient conditions are derived to ensure the finite-time stochastic stability with the prescribed <i>H</i><sub>∞</sub> performance for the relevant closed-loop system by employing the linear matrix inequality technique. Finally, the desired state feedback <i>H</i><sub>∞</sub> controller gain matrices can be expressed in an explicit form.展开更多
Characteristics of electron emission induced by a surface flashover trigger device in a low-pressure trigger switch were investigated. A test method to measure the emitted charges from the trigger device was developed...Characteristics of electron emission induced by a surface flashover trigger device in a low-pressure trigger switch were investigated. A test method to measure the emitted charges from the trigger device was developed, and the factors affecting the emitted charges were analyzed. The results indicated that the major emitted charges from the trigger device were induced by surface plasma generated by surface flashover occurring on the trigger dielectric material. The emitted charges and the peak emission current increased linearly with the change in the trigger voltage and bias voltage. The emitted charges collected from the anode were affected by the gap distance. However, the emitted charges were less affected by the anode diameter. Furthermore, the emitted charges and the peak emission current decreased rapidly with the increase in gas pressure in a range from 0 Pa to 100 Pa, and then remained stable or changed slightly when the increase in gas pressure up to 2400 Pa.展开更多
A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main dischar...A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseu- dospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface ttashover trigger device made of high relative perimittivity dielectric material BaTiO3 （εr = 3460）, the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current waveform of maximum 25 kA was generated with a rise time and time to half peak value of 17.2 μs and 336μs respectively.展开更多
High-power precise delay trigger/ignition system is a programmable pulse generator developed for experiment controlling in explosively driven magnetic flux compression generators. Precise delay pulses are generated by...High-power precise delay trigger/ignition system is a programmable pulse generator developed for experiment controlling in explosively driven magnetic flux compression generators. Precise delay pulses are generated by the digital circuit, after being magnified and sharpened through multistage isolated amplifiers and rising edge sharpening device, high-voltage steep delay pulses with precision less than μs level are obtained. This system has been used in our compact magnetic flux compression generator experiments in place of the traditional primaeord delay device.展开更多
High power switch is one of the most important components in pulsed power technology. The RSD （Reversely Switched Dynistor）, turned on by a thin layer of an electron-hole plasma, is a high power semiconductor switch...High power switch is one of the most important components in pulsed power technology. The RSD （Reversely Switched Dynistor）, turned on by a thin layer of an electron-hole plasma, is a high power semiconductor switch. In this study, the RSD turn-on conditions were investigated by numerical analysis and device simulation as well as the experiments conducted to validate the turn-on conditions. A design of a triggering high-voltage RSD is presented based on a saturable transformer.展开更多
基金supported by National Natural Science Foundation of China (No.10574096)the Research Fund for the Doctoral Program of Higher Education of China (No.20050610010)
文摘A high precision laser trigger system is built up in the single test module of Primary Test Stand （PTS） facility. A fourth harmonic, with a wavelength A of 266 nm, Q-switched Nd：YAG laser was used to trigger the 5 MV multi-gap multi-channel gas switch which was filled with high pressure SF6-N2 mixture gas. The maximum deviation and the standard deviation in the jitter time of the trigger system is 4- 0.7 ns and 0.3 ns respectively. The maximum deviation and the standard deviation in the jitter time for the multi-gap multi-channel laser triggering switch is 4- 2.4 ns and 1.5 ns respectively. The curve of switch delay-time versus laser energy is obtained, which is helpful for the choice of fitting laser energy. The successful test with two lasers indicated that the design of using twenty-four lasers to trigger twenty-four switches respectively is feasible in ＂PTS＂.
基金We gratefully acknowledge support from the Natural Science Foundation of Jiangsu Province of China(Grant No.BK20151486).
文摘Triggered spark-gap switch is a popular discharge switch for pulse power systems.Previous studies have focused on planarizing this switch using thin film techniques in order to meet the requirements of compact size in the systems.Such switches are one-shot due to electrodes being too thin to sufficiently resist spark-erosion.Additionally,these switches did not employ any structures in securing internal gas composition,resulting in inconsistent performance under harsh atmospheres.In this work,a novel planar triggered spark-gap switch(PTS)with a hermetically sealed cavity was batched-prepared with printed circuit board(PCB)technology,to achieve reusability with low cost.The proposed PTS was inspected by micro-computed tomography to ensure PCB techniques meet the requirements of machining precision.The results from electrical experiments demonstrated that PCB PTS were consistent and reusable with lifespan over 20 times.The calculated switch voltage and circuit current were consistent with those derived from real-world measurements.Finally,PCB PTS was used to introduce hexanitrostilbene(HNS)pellets in a pulse power system to verify its performance.
基金supported by the New Century Talent Foundation of Ministry of Education of China (NCET-08-0438)
文摘Triggering characteristics of triggered vacuum switch （TVS）, including the discharge delay time, delay jitter, range of operational voltage and peak of pulsed current, are investigated. Both structure and experimental circuit of TVS are presented. The results indicate that TVS, as a surface flashover triggering device with high dielectric permittivity material, is with excellent triggering characteristics. When the hold-off voltage reaches 120 kV, the minimum operational voltage is 1.3 kV, and the minimum discharge delay time and jitter are 100 ns and ±10 ns, respectively. The peak current is up to 240 kA when the operational voltage reaches 100 kV. TVS can well satisfy the main demands of high voltage and current applications, and can also be used under a multi-crowbar circuit.
文摘A trigger device and a triggered pseudospark switch （TPSS） were designed based on surface flashover technology, in order to meet the requirements from present pulse power technology and pulse current test technology such as a long lifetime, reliability in a wide voltage range, a short delay time, as well as small delay jitters. The trigger devices were made from different dielectric materials, with their permittivities from tens to thousands. The trigger characteristics of TPSS were investigated. The results indicate that the high-dielectric trigger device shows better performance and higher emitted charge of the electron emission within all adjusted parameters including the gas pressure and applied voltage. For the dielectric material with relative permittivity εr of 3460, when the gas pressure is 7 Pa, the hold-off voltage of TPSS is 28 kV, the minimum trigger switch voltage drops to 128 V, the minimum discharging delay time and delay jitter are less than 35ns and 6ns, respectively, and the reliable operation can be reached within a very large range of charging voltage, between 0.46% and 99% of its self-breakdown voltage.
文摘A 22-stage 4 MV laser-triggered multistage multi-channel switch （LTS） was designed according to the hypothesis that the well-proportioned electrical field distribution is helpful in reducing the jitter of delay. Field distribution in the switch section is regulated by a metal field regulation ring and several gradient rings. In order to reduce the jitter further, a SFB/N2 mixture is chosen as the switching medium. The generalized standard deviation of the self-breakdown voltage and the deviation of the average value from the prediction is less than 4.4% and 13% respectively. Linearity of the self-breakdown voltage is better than 0.95. Triggered by a laser pulse of 35 mJ/3 ns, the delay is about 26 ns at a working voltage of 85±3% USB （Self-breakdown Voltage）. Maximum deviation of delay is less than =t=2.5 ns. Jitter is less than 1.5 ns. The delay and jitter decrease with the increase in the working ratio （the ratio of working voltage to USB）, pressure or voltage.
基金supported by the Foundation of State Key Laboratory of Intense Pulsed Radiation Simulation and Effect (No. SKLIPR1601)
文摘Gas pressurized closing switches are one of the most important elements in FLTD-based systems. Improving the trigger performance of gas switches is useful for optimizing the output parameters and the reliability of the FLTD. In this paper, the breakdown characteristics of the trigger gap and the overvoltage gap are studied experimentally. The reasons for the different breakdown performance of the two gaps are also investigated. The results show that the breakdown delay of the trigger gap is more influenced by the trigger voltage, while the breakdown delay of the overvoltage gap is more influenced by the working coefficient and always higher than that of the trigger gap. The jitter of the trigger gap is more influenced by the trigger voltage and accounts more than 60% of the total switch jitter, while the jitter of the overvoltage gap is hardly changed with the trigger voltage as well as the working coefficient and maintains less than 1.4 ns. It is proved that the discharging product from the trigger gap can effectively reduce the breakdown delay and jitter of the overvoltage gap. Based on that, the effect and improvement of pre-ionization on the two gaps are also studied. It is concluded that the jitter of the trigger gap reduces obviously when the pre-ionization is added, while the pre-ionization almost has no effect on the jitter of the overvoltage gap. The jitter of the overvoltage gap is about two times higher than the trigger gap in the pre-ionizing switch.
基金supported by National Natural Science Foundation of China(No.51177131)the Fundamental Research Funds for the Central Universities of China(No.xjj20100159)
文摘The characteristics of the triggered vacuum switch （TVS） are obviously influenced by the emission current ie and emission charge of the trigger device. In this paper, an RC charge collector is designed, and the characteristics of emission current ie and collecting charge Qc of the trigger device are studied. The experimental results indicate that the emission current ie which is produced by the initial plasma has both positive and negative components, and the polarity of the emission current ie depends mainly on the polarity of the bias voltage UBias. The emission current ie and collecting charge Qe increase with the increase of the trigger voltage Utr and the bias voltage UBias. The emission efficient r] increases linearly with the increase of the bias voltage UBias. When the gap distance is 15 mm and bias voltage UBias is 160 V and trigger voltage Utr is 2.6 kV, the emission efficiency r/reaches 6%
基金Project supported by the National Natural Science Foundation of China(Grant No.11701138)the Natural Science Foundation of Hebei Province,China(Grant Nos.F2017202009 and F2018202075)
文摘This paper investigates the time-varying formation problem for general linear multi-agent systems using distributed event-triggered control strategy.Different from the previous works,to achieve the desired time-varying formation,a distributed control scheme is designed in an event-triggered way,in which for each agent the controller is triggered only at its own event times.The interaction topology among agents is assumed to be switching.The common Lyapunov function as well as Riccati inequality is applied to solve the time-varying formation problem.Moreover,the Zeno behavior of triggering time sequences can be excluded for each agent.Finally,a simulation example is presented to illustrate the effectiveness of the theoretical results.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61074159 and 61703286)
文摘We propose a new approach to discuss the consensus problem of multi-agent systems with time-varying delayed control inputs, switching topologies, and stochastic cyber-attacks under hybrid-triggered mechanism.A Bernoulli variable is used to describe the hybrid-triggered scheme, which is introduced to alleviate the burden of the network.The mathematical model of the closed-loop control system is established by taking the influences of time-varying delayed control inputs,switching topologies, and stochastic cyber-attacks into account under the hybrid-triggered scheme.A theorem as the main result is given to make the system consistent based on the theory of Lyapunov stability and linear matrix inequality.Markov jumps with uncertain rates of transitions are applied to describe the switch of topologies.Finally, a simulation example demonstrates the feasibility of the theory in this paper.
基金supported by National Natural Science Foundation of China(No.51177131)the New Century Talent Foundation of Ministry of Education of China(NCET-08-0438)
文摘Pseudo-spark switch（PSS） is one of the most widely used discharge switches for pulse power technology.It has many special characteristics such as reliability in a wide voltage range,small delay time,as well as small delay jitter.In this paper,the measuring method for the initial plasma of ZnO surface flashover triggering device of PSS is studied and the results of the measurement show that the electron emission charge is mainly influenced by trigger voltage,gas pressure and DC bias voltage.When the bias voltage increases from 2 kV to 6 kV with the gap distancc fixed at 3 mm,the electron emission charge changes from 2 μC to about 6μC.When the gap distance changes from 3 mm to 5 mm with the bias voltage fixed at 2 kV,the electron emission charge increases from 1.5 μC to 2.5μC.When the gap distance is 4 mm,the hold-off voltage of PSS is 45 kV at gas pressure of 2 Pa,the minimum operating voltage is less than 1 kV.So,the operating scope is from 2.22%to 99%of its self-breakdown voltage.The discharging delay time decreases from 450 ns to 150 ns when the trigger pulse voltage is 1 kV and the discharging voltage is changed from 1 kV to 12 kV.When the trigger pulse voltage is 6 kV,the discharging delay time is less than 100 ns and changes from 100 ns to 50 ns,and the delay jitters are less than30 ns.
文摘Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.
基金The project supported by the National Nature Science Foundation of China(No.10035020)
文摘Accurate and reliable triggering is one of the most important issues with high power pseudospark switch, because it not only has an impact on the design of discharge chamber of switch, but also has an influence on the dynamic range of operation voltage, repetition frequencies and lifetime of switch. The unique feature of pseudospark switch is its hollow cathode geometry. The hollow cathode effect produced by the hollow cathode provides the protection of the switch for the triggering unit from erosion by high discharge plasma. In this paper, a zinc oxide (ZnO) surface flashover triggering is presented. This trigger unit possesses an excellent time delay (80 ns - 360 ns) and jitter (20 ns - 50 ns) at the switch voltage of 30 kV - 2 kV. The emitted plasma electron density is high enough to trigger switch reliably down to switch voltage of 440 V.
文摘This paper investigates the problem of event-triggered finite-time <i>H</i><sub>∞</sub> control for a class of switched stochastic systems. The main objective of this study is to design an event-triggered state feedback <i>H</i><sub>∞</sub> controller such that the resulting closed-loop system is finite-time bounded and satisfies a prescribed <i>H</i><sub>∞</sub> level in some given finite-time interval. Based on stochastic differential equations theory and average dwell time approach, sufficient conditions are derived to ensure the finite-time stochastic stability with the prescribed <i>H</i><sub>∞</sub> performance for the relevant closed-loop system by employing the linear matrix inequality technique. Finally, the desired state feedback <i>H</i><sub>∞</sub> controller gain matrices can be expressed in an explicit form.
基金supported by the New Century Talent Foundation of Ministry of Education of China (NCET-08-0438)
文摘Characteristics of electron emission induced by a surface flashover trigger device in a low-pressure trigger switch were investigated. A test method to measure the emitted charges from the trigger device was developed, and the factors affecting the emitted charges were analyzed. The results indicated that the major emitted charges from the trigger device were induced by surface plasma generated by surface flashover occurring on the trigger dielectric material. The emitted charges and the peak emission current increased linearly with the change in the trigger voltage and bias voltage. The emitted charges collected from the anode were affected by the gap distance. However, the emitted charges were less affected by the anode diameter. Furthermore, the emitted charges and the peak emission current decreased rapidly with the increase in gas pressure in a range from 0 Pa to 100 Pa, and then remained stable or changed slightly when the increase in gas pressure up to 2400 Pa.
文摘A crowbar impulse current circuit for testing the switch-type surge protective device （SPD） is presented. The crowbar circuit consists of a computer control circuit, a trigger voltage pulse generator, a main discharging switch, and a crowbar pseudospark switch. The active trigger technology was studied in the crowbar impulse current circuit. The circuit monitors the main discharging current and generates a trigger signal at a proper time for the crowbar pseudospark switch operation. The trigger characteristics of the main discharge switch and the crowbar pseu- dospark switch were investigated. By monitoring the preset applied capacitor voltage, the gap distance of the main discharging switch could be adjusted to ensure a discharging delay time less than 2 μs. Equipped with a surface ttashover trigger device made of high relative perimittivity dielectric material BaTiO3 （εr = 3460）, the discharge delay time of the crowbar pseudospark switch is less than 85 ns, and the minimum operating voltage is less than 1% of its self-breakdown voltage. With a storage capacitor of 9 μF , an inductor of 18 μH and a crowbar pseudospark switch, a load of 30 mΩ and an applied capacitor voltage of 40 kV, an impulse current waveform of maximum 25 kA was generated with a rise time and time to half peak value of 17.2 μs and 336μs respectively.
基金the Ministerial Level Advanced Research Foundation(40407010305)
文摘High-power precise delay trigger/ignition system is a programmable pulse generator developed for experiment controlling in explosively driven magnetic flux compression generators. Precise delay pulses are generated by the digital circuit, after being magnified and sharpened through multistage isolated amplifiers and rising edge sharpening device, high-voltage steep delay pulses with precision less than μs level are obtained. This system has been used in our compact magnetic flux compression generator experiments in place of the traditional primaeord delay device.
基金supported by the National Natural Science Foundation of China (Nos.50277016,50577028)Specialized Research Fund for the Doctoral Program of Higher Education (No.20050487044)
文摘High power switch is one of the most important components in pulsed power technology. The RSD （Reversely Switched Dynistor）, turned on by a thin layer of an electron-hole plasma, is a high power semiconductor switch. In this study, the RSD turn-on conditions were investigated by numerical analysis and device simulation as well as the experiments conducted to validate the turn-on conditions. A design of a triggering high-voltage RSD is presented based on a saturable transformer.
