A Pulse Power Supply and Method Based on an Optical Conduction Switch and an LTD Circuit

Abstract

The present invention discloses a pulse power supply and method based on an optically triggered switch and an LTD circuit. A high-voltage charging system and a laser diode triggering system are connected to a high-voltage forming system. The optoelectronic synchronization system triggers the high-voltage charging system through an electrical trigger signal to provide a high-voltage condition for each unit of the optically triggered switch to conduct. The optoelectronic synchronization system triggers the laser diode triggering system through an optical trigger signal, and the laser diode triggering system generates a laser signal to irradiate the optically triggered switch. The high-voltage forming system is used to output high-voltage repetitive nanosecond pulses. By sharing the current pressure through each unit and superimposing the voltage induction of each module, the requirements for the conduction current and withstand voltage of the optically triggered switch are reduced, making the optically triggered switch stable and reliable, significantly increasing the lifespan of the device, and capable of obtaining high-amplitude, fast-front, high-repetition-rate voltage nanosecond pulses on both high-load impedance and low-load impedance, with a long lifespan, high reliability, a compact structure, a small volume, and a light weight.

Description

Technical Field

[0001] The present invention belongs to the field of pulse power discharge and pulse laser synchronous control, and particularly relates to a pulse power supply and method based on an optically triggered switch and an LTD circuit. Background Art

[0002] The essence of pulse power technology is to compress energy in the time and space scales to obtain high power output and high energy density. Since the Linear Transformer Driver (LTD) technology was first applied to the Modul device in Russia in the 1970s, the LTD technology has been generally regarded as a potential driving source for realizing repetitive frequency operation due to its advantages such as modularity, compact structure, flexible design, and high energy transmission efficiency. At the 2007 International Pulse Power Conference, M.K. Matzen, the person in charge of the Sandia National Laboratories in the United States, even called the LTD the next-generation pulse power technology. In the LTD pulse power technology, the switch plays an important role, which not only determines the output characteristics of the pulse power device, but even to some extent is the key to the success or failure of the pulse power system. Currently, the successfully developed LTD mainly uses gas switches, which are mainly for single-shot operation due to their large volume, electrode ablation, short service life, and relatively complex maintenance; Jiang Weihua et al. were the first to apply all-solid-state switches to the LTD, greatly improving the compactness and repetition frequency of the device, but the power capacity of a single MOSFET switch is small, and to obtain the target voltage, it is necessary to increase the number of MOSFETs at the expense of bringing a thorny problem of synchronous triggering of switches. In summary, the main bottleneck in the application of the LTD lies in the performance of the switch itself and precise synchronization. Summary of the Invention

[0003] The purpose of the present invention is to provide a pulse power supply and method based on an optically triggered switch and an LTD circuit to overcome the deficiencies of the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A pulse power supply based on an optically triggered switch and an LTD circuit includes an optoelectronic synchronization system, a high-voltage charging system, a laser diode triggering system, and a high-voltage forming system. The optoelectronic synchronization system is used to control the high-voltage charging system to charge the energy storage device in the high-voltage forming system (4) through an electrical trigger signal; both the high-voltage charging system and the laser diode triggering system are connected to the high-voltage forming system to provide a conducting high-voltage condition and a light trigger condition for each unit of the optically triggered switch; the optoelectronic synchronization system is used to trigger the laser diode triggering system through a light trigger signal, the laser diode triggering system generates a laser signal to irradiate the optically triggered switch, and the high-voltage forming system is used to output a high-voltage repetitive nanosecond pulse.

[0006] Furthermore, a delay module is provided in the optoelectronic synchronization system for achieving the time interval between the electrical trigger signal and the optical trigger signal.

[0007] Furthermore, the laser diode trigger system includes an LD drive circuit module and an LD module. The LD drive circuit module is used to convert the optical trigger signal into a drive signal, thereby causing the laser diode in the LD module to emit laser light.

[0008] Furthermore, the high-voltage forming system includes LTD modules connected in series at the X level, where X≥1, and the output voltages of each level of LTD modules are serially superimposed in sequence on the secondary side.

[0009] Furthermore, each level of LTD module in the high-voltage forming system includes Y units based on photoconductive switches, where Y≥1.

[0010] Furthermore, the unit based on the photoconductive switch includes a photoconductive switch and an energy storage device.

[0011] Furthermore, each unit based on the photoconductive switch in the LTD module contains the same N-level Marx circuit based on the photoconductive switch, and each level of the Marx circuit is connected to a photoconductive switch and an energy storage device.

[0012] Furthermore, the number of the LD drive circuit module and the LD module in the laser diode trigger system is the same as the number of the units based on the photoconductive switch in the high-voltage forming system.

[0013] Furthermore, the repetition frequency, pulse width, amplitude, and phase of the electrical pulse signal and the optical trigger signal are adjustable.

[0014] A pulse control method for a pulse power supply based on a photoconductive switch and an LTD circuit includes the following steps:

[0015] Set the interval time between the output electrical trigger signal and the optical trigger signal of the optoelectronic synchronization system according to the rise time of the bias voltage of the photoconductive switch, and then use the optoelectronic synchronization system to trigger the high-voltage charging system and the laser diode trigger system respectively with the electrical trigger signal and the optical trigger signal. The high-voltage charging system charges the energy storage unit in the high-voltage forming system to provide the high-voltage condition required by the photoconductive switch; each laser diode trigger unit emits laser light to irradiate the photoconductive switch in its corresponding unit of the high-voltage forming system to provide the light source condition required for its conduction. The high-voltage forming system conducts current according to the received optical trigger signal, and the pulse generated on the primary side is coupled to the secondary side through electromagnetic induction for serial superposition to output a fast-front repetitive-frequency high-voltage nanosecond pulse.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects:

[0017] The present invention relates to a pulse power supply based on an optical switch and an LTD circuit, which adopts a high-voltage charging system and a laser diode triggering system to connect a high-voltage forming system. The photoelectric synchronization system triggers the high-voltage charging system through an electrical trigger signal to provide a high-voltage condition for the conduction of each unit of the optical switch. The photoelectric synchronization system is used to output an optical trigger signal to trigger the laser diode triggering system. The laser diode triggering system generates a laser signal to irradiate the optical switch. The high-voltage forming system is used to output a high-voltage repetitive nanosecond pulse. Adopting this control method can greatly increase the lifespan of the overall pulse source. And compared with the laser triggering system, by using the laser diode triggering system, the overall system becomes miniaturized and compact, which is convenient for carrying and practical application, and also greatly reduces its cost and maintenance price during operation. By sharing the current pressure among each unit and superimposing the voltage induction of each module, the requirements for the conduction current and withstand voltage of the optical switch are reduced, making the optical switch stable and reliable, significantly increasing the lifespan of the device, and being able to obtain high-amplitude, fast-front, high-repetition-rate voltage nanosecond pulses on both high-load impedance and low-load impedance, with a long lifespan, high reliability, a compact structure, a small volume, and a light weight. The optical switch adopted in the present invention has a fast response speed, small time jitter, high breakdown voltage, high repetition frequency, photoelectric isolation, and strong anti-interference ability. Compared with the previous semiconductor switch, it has a higher withstand voltage (more than 10 kV compared to 1 kV of the semiconductor switch).

[0018] Furthermore, by using LTD units to share the current pressure and superimposing the voltage induction of each module, the requirements for the conduction current and withstand voltage of the optical switch are reduced, making the optical switch stable and reliable, significantly increasing the lifespan of the device, and the parallel connection of multiple units reduces the structural inductance, which can make the front edge of the output pulse faster.

[0019] Furthermore, LTD realizes the induction and superposition of voltage through the magnetic core of each module, making the voltage of the entire device piecemeal. The voltage of the LTD circuit of each module is relatively low, reducing the requirement for insulation.

[0020] Furthermore, by combining the Marx circuit and the LTD circuit, compared with the independent Marx circuit, the current borne by each unit of the optical switch in each module of the LTD circuit can be changed to 1 / Y (Y≥1) of the original, and it can be applied to both high-load impedance occasions and low-load impedance occasions. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a circuit principle block diagram in an embodiment of the present invention.

[0022] Figure 2 It is a schematic diagram of the high-voltage forming system in an embodiment of the present invention.

[0023] Figure 3Schematic diagram of the platform in the embodiments of the present invention.

[0024] Figure 4(a) is a top view of the laser diode triggering system and the high-voltage forming system in the embodiments of the present invention.

[0025] Figure 4(b) is a schematic diagram of a two-stage photoconductive switch-based Marx circuit in the high-voltage forming unit 41 of the LTD module 1 of the high-voltage forming system in the embodiments of the present invention.

[0026] In the figure, 1 is the optoelectronic synchronization system; 2 is the high-voltage charging system; 3 is the laser diode triggering system; 4 is the high-voltage forming system; 41 is the LTD module. Detailed implementation manners

[0027] The present invention will be further described in detail below with reference to the accompanying drawings:

[0028] As Figure 1 shown, a pulse power supply based on a photoconductive switch and an LTD circuit includes an optoelectronic synchronization system 1, a high-voltage charging system 2, a laser diode triggering system 3, and a high-voltage forming system 4. The optoelectronic synchronization system 1 controls and triggers the high-voltage charging system 2 through a control circuit using an electrical trigger signal. The high-voltage charging system 2 is connected to the high-voltage forming system 4 to provide a conductive high-voltage condition for each unit of the photoconductive switch. After a certain delay, the optoelectronic synchronization system 1 outputs an optical trigger signal to trigger the laser diode triggering system 3. The laser diode triggering system 3 generates a laser signal to irradiate the photoconductive switch, providing the optical trigger condition required for its conduction. The Marx circuits based on photoconductive switches in each unit of each stage of the LTD module in the high-voltage forming system 4 are simultaneously turned on. The pulses generated on the primary side of each module are coupled to the secondary side through electromagnetic induction and serially superimposed to output a high-voltage repetitive nanosecond pulse.

[0029] The optoelectronic synchronization system 1 is used to output electrical pulse signals and optical trigger signals with adjustable repetition frequency, pulse width, amplitude, and phase. There is a time interval between the electrical trigger signal and the optical trigger signal output by the optoelectronic synchronization system 1. This time interval is set by the rise time of the bias voltage of the photoconductive switch. A delay module is provided in the optoelectronic synchronization system 1 to achieve the time interval between the electrical trigger signal and the optical trigger signal, thereby greatly improving the service life of the photoconductive switch.

[0030] The laser diode triggering system 3 includes an LD driving circuit module and an LD module. The LD driving circuit module is used to convert the optical trigger signal into a driving signal to cause the laser diode in the LD module to emit laser light, providing the light source condition required for the conduction of the photoconductive switch in the high-voltage forming system 4.

[0031] The high-voltage forming system 4 is composed of X (X≥1) stages of LTD modules connected in series. Each stage of the LTD module is equivalent to a 1:1 transformer. The output voltages of each stage of the LTD module are serially superimposed in turn on the secondary side, and X (X≥1) times the output voltage of one stage of the LTD module is output at the upper end of the first stage and the lower end of the last stage on the secondary side.

[0032] Each stage of the LTD module of the high-voltage forming system 4 includes Y units based on photoconductive switches, where Y≥1. Y (Y≥1) units based on photoconductive switches are connected in parallel to output to the primary side of a single-stage LTD. Therefore, each unit based on a photoconductive switch bears 1 / Y (Y≥1) of the current on the actual load. Compared with an independent unit circuit, the pulse current conduction capacity of the pulse power supply is increased by Y (Y≥1) times, greatly increasing the service life of the photoconductive switch.

[0033] The unit based on a photoconductive switch in the high-voltage forming system 4 includes a photoconductive switch and an energy storage device, and is used to realize energy storage and pulse discharge based on the photoconductive switch.

[0034] Each unit based on a photoconductive switch of each stage of the LTD module of the high-voltage forming system 4 contains the same N-stage Marx circuit based on a photoconductive switch. Each stage of the Marx circuit is connected to a photoconductive switch and an energy storage device. Compared with a single-stage Marx circuit, the output voltage of each unit is increased by N (N≥1) times.

[0035] The number of LD drive circuit modules and LD modules in the laser diode trigger system 3 is the same as that of the units based on photoconductive switches in the high-voltage forming system 4, which is X×Y×N (X≥1, Y≥1, N≥1).

[0036] In order to make the purpose, technical solution and advantages of the present invention clearer, the following further details the technical solution of the present invention in combination with an LTD pulse power supply with a 2-module 4-unit 2-stage Marx circuit based on a photoconductive switch. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] As Figure 2 、 Figure 3 shown, the multivibrator circuit composed of a 555 timer in the optoelectronic synchronization system generates an initial control pulse. By adjusting the capacitance and variable resistance of the peripheral circuit, the repetition frequency can be adjusted between 1 Hz and 1 kHz. The initial control pulse generated by the multivibrator circuit is divided into two paths. One path is directly output after pulse width modulation and current amplification, that is, the "electrical trigger signal". In order to synchronize the moment when the photoconductive switch reaches the peak voltage and the moment when the LD emits laser during charging, the other path needs to be output after passing through a delay module composed of two cascaded 74LS192 counters, which is called the "optical trigger signal";

[0038] The electrical trigger signal arrives at the high-voltage charging system. Meanwhile, an external DC voltage is input to the system. The input alternating current is converted into pulses on the primary side through a flyback transformer and coupled to the secondary side through an autotransformer to generate a high voltage with an amplitude of +V CC , and after being transmitted over the same distance, it arrives at the LTD module of the high-voltage formation system. It is respectively transmitted 1 / 4 of the circumference along the circumferential direction to points A and C of the two LTD modules of the high-voltage formation system, and then respectively transmitted 1 / 8 of the circumference along the circumferential direction to be connected to two parallel capacitor energy storage devices C1 and C2 of each Marx charging circuit in the 1-4 high-voltage formation units of the LTD module of the high-voltage formation system, and they are respectively charged to +V CC , and provide the high-voltage conditions required for the conduction of the 2 photoconductive switches that are not yet conducting in the 2-stage Marx circuit at this time;

[0039] After a certain delay, the optical trigger signal (control signal) output by the optoelectronic synchronization system arrives at the modules in the laser diode trigger system after an equal-length distance. The optical trigger signal is respectively transmitted 1 / 4 of the circumference along the circumferential direction to points M and P of the two LTD modules in the laser diode trigger system, and then respectively transmitted 1 / 8 of the circumference along the circumferential direction to the 1-4 trigger units of the two LTD modules in the laser diode trigger system. After operations such as pulse shaping and current signal amplification, the shaped trigger signal is transmitted to the 2 LD circuits of each laser diode trigger unit, and the LDs simultaneously emit laser light to irradiate the 2 photoconductive switches in the 2-stage Marx circuit of the 1-4 high-voltage formation units of the LTD module of the high-voltage formation system corresponding to the radially inner side, providing the light source conditions required for their conduction. Under the combined action of the light source conditions and the high-voltage conditions, the photoconductive switches in each Marx circuit of the 1-4 high-voltage formation units of the two LTD modules of the high-voltage formation system are simultaneously turned on;

[0040] The first-stage photoconductive switch PCSS1 in the 2-stage Marx discharge circuit of the 1-4 high-voltage formation units of the LTD module 1 of the high-voltage formation system and the LTD module 2 of the high-voltage formation system is fully turned on. Therefore, the potential of the left plate of the capacitor C1 changes from +V CC to approximately zero. Since the potential difference across the capacitor plates cannot change suddenly, the potential of the right plate becomes -V CC , and PCSS2 is also in a fully turned-on state at this time, that is, the potential of the left plate of the capacitor C2 changes from +V CC to approximately -V CC , so the Marx circuits of the 1-4 high-voltage formation units all output -2V CC . The 4 high-voltage formation units of the high-voltage formation system 1 are connected in parallel on the primary side to generate an amplitude of approximately 2V CCThe negative pulse is coupled to the secondary side through the electromagnetic induction of the magnetic core. At the same time, the four high-voltage forming units of the high-voltage forming system 2 are connected in parallel to generate a negative pulse with an amplitude of about 2V. CC The negative pulse of CC is also coupled to the secondary side through the magnetic core. The two pulses are serially superimposed on the secondary side, and finally about 4V is output on the load. CC Fast-front repeated-frequency high-voltage nanosecond negative pulses.

[0041] A high-voltage pulse control method based on the above pulse power supply includes the following steps:

[0042] S1. The optoelectronic synchronization system 1 serves as a control circuit and triggers the high-voltage charging system 2 through an electrical trigger signal (control signal). The high-voltage charging system 2 is connected to the high-voltage forming system 4 and is used to provide high-voltage conditions for the conduction of each photoconductive switch. Before triggering, the high-voltage charging system charges the energy storage device to provide the high-voltage conditions required for the conduction of the photoconductive switch.

[0043] S2. After a certain delay, the optoelectronic synchronization system 1 then reaches each laser diode trigger system 3 through an optical trigger signal (control signal) via an equal-length line.

[0044] S3. Each laser diode trigger unit emits laser light to irradiate the photoconductive switch in the corresponding unit of the high-voltage forming system 4, providing the light source conditions required for its conduction.

[0045] S4. The Marx circuits based on photoconductive switches in each unit of each stage LTD module in the high-voltage forming system 4 are simultaneously turned on. The pulses generated on the primary side are coupled to the secondary side through electromagnetic induction and are serially superimposed to output fast-front repeated-frequency high-voltage nanosecond pulses.

[0046] The pulse power supply based on photoconductive switches and LTD circuits adopted by the present invention has stable operation, high reliability, and long service life. When the photoconductive switch is turned on, due to the limitation of the withstand current, there is still a large gap between its life at a relatively high output power and the actual application. The LTD shares the current pressure through each unit and superimposes the voltage induction of each module, reducing the requirements for the conduction current and withstand voltage of the photoconductive switch, making the photoconductive switch stable and reliable, and significantly increasing the service life of the device. At the same time, the life of the photoconductive switch will be significantly shortened when it is in a high-voltage state for a long time. On the contrary, if it starts to work before reaching the voltage peak, the output power of the pulse source will be reduced. Therefore, after the optoelectronic synchronization system (1) outputs an "electrical trigger signal", an "optical trigger signal" is output after a certain delay. The amount of this delay should be set by the rise time of the PCSS bias voltage and is specifically implemented by a delay module. By taking both measures, the service life of the pulse power supply based on the LTD circuit with photoconductive switches has achieved a qualitative leap.

[0047] High synchronization accuracy, high repetition frequency, compact structure, and low cost. Compared with traditional LTD and Marx circuits that use gas switches (large volume, low repetition frequency) and MOSFETs (complicated synchronous trigger system), photoconductive switches have significant advantages such as high voltage withstand and fast switching speed. However, they require a large amount of trigger light energy and complex equipment. The present invention designs a laser diode trigger system (3) with a modular three-dimensional symmetric structure. The high-synchronization driving LD replaces the large-volume laser, making the system miniaturized and compact, facilitating portability and practical applications, and also greatly reducing its cost and maintenance price during operation.

[0048] High voltage amplitude and short pulse front. Traditional all-solid-state LTD and Marx circuits mostly use MOSFETs. The breakdown voltage of a single switch is about 1 kV, and multiple MOSFETs need to be connected in series and parallel to reach the target high voltage. However, the breakdown voltage of a single photoconductive switch can reach 10 kV or even higher. Combined with the voltage superposition of each stage of the Marx circuit unit and the series connection of multiple LTD modules, the voltage amplitude is significantly increased. Photoconductive switches also have a switching speed on the order of picoseconds. The entire device is very compact with small structural inductance, greatly shortening the pulse front. The insulation requirement is low, and it is easy to achieve high-voltage output. LTD realizes the inductive superposition of voltage through the magnetic core of each module, making the voltage of the entire device divided into zero. The voltage of each LTD circuit module is relatively low, reducing the insulation requirement.

[0049] Wide load application range. Combining the Marx circuit and the LTD circuit, compared with an independent Marx circuit, the current borne by each photoconductive switch in each unit of the LTD circuit of each module can be changed to 1 / Y (Y≥1) of the original, enabling it to be applied in both high-load impedance and low-load impedance scenarios.

[0050] The above content is a further detailed description of the present invention in combination with specific implementation manners, and is not used to limit the present invention. For those of ordinary skill in the technical field of the present invention, any simple deduction, substitution, modification, improvement, etc. made without departing from the concept of the present invention shall be included within the protection scope of the present invention.

Claims

1. A pulse power supply based on an optically controlled switch and an LTD circuit, characterized in that It includes an optoelectronic synchronization system (1), a high-voltage charging system (2), a laser diode triggering system (3), and a high-voltage forming system (4). The optoelectronic synchronization system (1) is used to control the high-voltage charging system (2) to charge the energy storage device in the high-voltage forming system (4) through an electrical trigger signal; both the high-voltage charging system (2) and the laser diode triggering system (3) are connected to the high-voltage forming system (4) to provide the high-voltage condition and light trigger condition for conduction for each unit of the photoconductive switch; the optoelectronic synchronization system (1) is used to trigger the laser diode triggering system (3) through a light trigger signal, the laser diode triggering system (3) generates a laser signal to irradiate the photoconductive switch, and the high-voltage forming system (4) is used to output a high-voltage repetitive nanosecond pulse. The laser diode triggering system (3) includes an LD driving circuit module and an LD module. The LD driving circuit module is used to convert the light trigger signal into a driving signal so that the laser diode in the LD module emits laser. The high-voltage forming system (4) includes X LTD modules connected in series, X ≥1. The output voltages of each LTD module are sequentially connected in series and superimposed on the secondary side. Each LTD module of the high-voltage forming system (4) includes Y units based on photoconductive switches, where Y≥1.

2. The pulsed power supply based on an optical switch and an LTD circuit according to claim 1, wherein The optoelectronic synchronization system (1) is provided with a delay module for achieving the time interval between the electrical trigger signal and the optical trigger signal.

3. The pulse power supply based on an optical switch and an LTD circuit according to claim 1, wherein The unit based on the photoconductive switch includes a photoconductive switch and an energy storage device.

4. A pulse power supply based on an optical switch and an LTD circuit according to claim 1, characterized in that, Each unit based on the photoconductive switch of the LTD module contains the same N-stage Marx circuit based on the photoconductive switch, and each stage of the Marx circuit is connected to a photoconductive switch and an energy storage device.

5. A pulse power supply based on an optical switch and an LTD circuit according to claim 1, characterized in that The number of the LD drive circuit module and the LD module in the laser diode trigger system (3) is the same as that of the units based on the photoconductive switch in the high-voltage forming system (4).

6. The pulsed power supply based on an optical switch and an LTD circuit according to claim 1, characterized in that, The repetition frequency, pulse width, amplitude, and phase of the electrical pulse signal and the optical trigger signal are adjustable.

7. A pulse control method for the pulse power supply according to claim 1, characterized in that, It includes the following steps: Set the interval time between the output electrical trigger signal and the optical trigger signal of the optoelectronic synchronization system according to the rise time of the bias voltage of the photoconductive switch, and then use the optoelectronic synchronization system to trigger the high-voltage charging system and the laser diode trigger system with the electrical trigger signal and the optical trigger signal respectively. The high-voltage charging system charges the energy storage unit in the high-voltage forming system to provide the high-voltage condition required by the photoconductive switch; each laser diode trigger unit emits laser light to irradiate the photoconductive switch in its corresponding unit of the high-voltage forming system to provide the light source condition required for its conduction. The high-voltage forming system conducts current according to the received optical trigger signal, and the pulse generated in the primary side is coupled to the secondary side through electromagnetic induction for series superposition to output a fast-front repetitive frequency high-voltage nanosecond pulse.

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