Solid-state repetition-frequency pulse generator driven by multiple paths of synchronous optical fibers and control method

Abstract

The invention belongs to the technical field of pulse power, and relates to a solid-state repetition-frequency pulse generator driven by multiple paths of synchronous optical fibers and a control method, the solid-state repetition-frequency pulse generator comprises a drive control circuit, the drive control circuit is connected with a Marx generator, and an AC-DC converter and a plurality of groups of IGBT switching circuits connected in series are arranged in the Marx generator; and the AC-DC converter is electrically connected with the group of IGBT switching circuits. In the topological structure, a plurality of IGBTs connected in series only need a gate driving voltage signal to drive the lowermost IGBT switching circuit, and other IGBT switching circuits are connected in series with one another, so that the IGBT switching circuits are sequentially conducted in an extremely short time, and synchronous driving is realized. Based on the circuit structure, a plurality of IGBT devices are modularly designed, and each module only needs one driving signal, so that the number of driving circuits is reduced, and the circuit structure is more compact.

Description

Technical Field

[0001] The invention belongs to the technical field of pulse power, and relates to a multi-channel synchronous optical fiber driven solid-state repetition rate pulse generator and a control method. Background Art

[0002] Currently, the field of pulse power technology is shifting its focus to the development of high-repetition-rate, high-precision, high-voltage pulse sources, a key R&D trend in the field. Pulse sources with solid-state switches as their core components, due to their high power, high repetition rate, high stability, and high reliability, have shown extremely broad application potential in pulse power technology.

[0003] When testing the electromagnetic pulse conduction effects of long cable systems, such as overhead power lines, high-voltage pulses must be injected at multiple locations along the line, with voltages reaching tens of kilovolts. Precise time delays must be maintained between the injection pulses at each location. Locating soft faults in power line networks using reflection methods also requires injecting high-voltage pulses at multiple locations within the network, with precise control of the injection timing to achieve good fault location accuracy. In fields such as PCB manufacturing and advanced semiconductor packaging, precise control of the output delay differences between multiple high-voltage repetition-rate pulse sources is also required to improve manufacturing precision.

[0004] For scenarios such as electromagnetic pulse conduction effect testing, power line fault location, and PCB manufacturing, a high-frequency high-voltage pulse generator with precise control of pulse output delay is required. Its output amplitude reaches tens of kV, and the delay difference of multiple output pulse waveforms is controlled within 0.1μs.

[0005] Marx generators based on IGBT switches are a common technology for high-frequency high-voltage pulse generators. However, in a Marx pulse generator, if all IGBT switches are controlled, the number of IGBT switch drive control units and their power supply units increases with the number of cascaded switches. This inevitably makes the switch drive portion of the entire system more complex. The increased number of cascaded switches also leads to significant jitter in the waveform output delay, making precise control difficult. Furthermore, the synchronous drive of each IGBT switch requires high-voltage isolation, but current commercial isolated power supplies have insufficient withstand voltage and cannot stably control the synchronization of the drive timing of pulse generators hundreds of meters apart. Therefore, precise control of the delay difference of multiple output high-voltage pulse waveforms is difficult. Summary of the Invention

[0006] The purpose of the present invention is to provide a multi-channel synchronous optical fiber driven solid-state repetition rate pulse generator and control method to solve the technical problem in the prior art that the synchronous drive of multiple IGBT switches cannot be stably controlled, and therefore it is difficult to achieve precise control of the delay difference of the multi-channel output high-voltage pulse waveform.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions: In the first aspect, the present application discloses a multi-channel synchronous optical fiber driven solid-state repetition rate pulse generator, including a drive control circuit, the drive control circuit is connected to a Marx generator, and the Marx generator is provided with an AC-DC converter and several groups of IGBT switching circuits connected in series; the AC-DC converter is electrically connected to a group of IGBT switching circuits.

[0008] Preferably, the IGBT switching circuit includes an energy storage capacitor and an IGBT switching component; the energy storage capacitor and the IGBT switching component are connected in series, and the IGBT switching component is further provided with a charging resistor and a ground isolation resistor.

[0009] Preferably, the IGBT switch component is an insulated gate bipolar transistor, and the ground isolation resistor is arranged between the drain and source of the insulated gate bipolar transistor; the charging resistor is arranged between the gate and the source, and the energy storage capacitor is connected to the gate; and the first group of IGBT switch circuits in the series-connected IGBT switch circuits is connected to a DC power supply; a Zener diode is connected in reverse parallel between the gate and the source of the insulated gate bipolar transistor.

[0010] Preferably, the series connection mode of the IGBT switch circuit includes: series energy storage capacitors, inter-pole cascade energy storage capacitors and independent grounded energy storage capacitors.

[0011] Preferably, in the series connection of the energy storage capacitors, the capacitance of the energy storage capacitors is calculated by the following formula:

[0012]

[0013] Where, is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE poles of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the CG electrodes of the IGBT; is the voltage between the two GC levels of the first-level IGBT; is the energy storage capacitor of the i+1th level IGBT; The value of is 1, 2, ... n-1; n is the number of stages of the series-connected IGBT switching circuits.

[0014] Preferably, in the series connection of the independent grounded energy storage capacitors, the capacitance of the energy storage capacitor is calculated by the following formula:

[0015]

[0016] Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the two CG stages of the IGBT; Capacitor The voltage on The value of is 2, 3, ... n-1; n is the number of groups of IGBT switching circuits connected in series.

[0017] Preferably, in the series connection of the inter-polar cascade energy storage capacitors, the capacitance values ​​of the energy storage capacitors are equal and are calculated by the following formula:

[0018] Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the two CG stages of the IGBT; Energy storage capacitor The voltage on.

[0019] Preferably, the drive control circuit includes a signal generator, a drive circuit and an isolation module; the signal generator is connected to the drive circuit, the drive circuit is connected to the isolation module, the isolation module is electrically connected to a group of IGBT switching circuits, and the group of IGBT switching circuits is an IGBT switching circuit connected to an AC-DC converter; the isolation module includes an optical fiber isolation module and a voltage isolation module.

[0020] In a second aspect, the present application discloses a control method for a multi-channel synchronous fiber-driven solid-state repetition rate pulse generator, comprising: When the driving signal of the driving control circuit is maintained at a negative voltage level, several groups of IGBT switching circuits connected in series are disconnected; When the driving signal of the driving control circuit becomes a stable positive voltage level, several groups of IGBT switching circuits connected in series are turned on; When the driving signal of the driving control circuit changes from a stable positive voltage level to a negative voltage level, the plurality of groups of IGBT switching circuits connected in series are disconnected.

[0021] Preferably, the IGBT switching circuit includes an energy storage capacitor and an IGBT switching component, then: When the driving signal of the driving control circuit is maintained at a negative voltage level, in the plurality of groups of series-connected IGBT switch circuits, the IGBT switch components are disconnected and the energy storage capacitor is charged; When the driving signal of the driving control circuit becomes a stable positive voltage level, the energy storage capacitors in the series-connected IGBT switching circuits are discharged and the IGBT switching components are turned on; When the driving signal of the driving control circuit changes from a stable positive voltage level to a negative voltage level, the IGBT switch components in the plurality of groups of series-connected IGBT switch circuits are disconnected.

[0022] Compared with the prior art, the present invention has the following beneficial effects: Through theoretical analysis and calculation, and after considering the technical indicators and specific application requirements of the solid-state high-repetition-rate pulse generator, the present invention designs a switching circuit based on a self-triggering structure consisting of several IGBTs connected in series, and a multi-channel synchronous drive and isolation circuit suitable for the IGBT series switching circuit. The switching circuit can normally switch while withstanding a voltage of 20kV, and the conduction time is within 50ns. It also obtains a square wave signal that meets the driving requirements of the IGBT series switching circuit, and the error between any two channels is within 20ns, with good consistency.

[0023] Compared to traditional pulse generators composed of gas switches, this invention uses insulated gate bipolar transistors as switches, resulting in a smaller device and a longer lifespan. The invention also uses optical fiber for multi-channel synchronous drive, improving system stability in strong electromagnetic environments and simplifying isolation circuit design. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0025] Figure 1 1 is a block diagram of the overall structure of the pulse source system according to an embodiment of the present invention; Figure 2 This is a circuit structure diagram of a series IGBT module according to an embodiment of the present invention; Figure 31 are other self-triggering circuit structure diagrams of embodiments of the present invention; wherein (a) is a structure diagram of an inter-stage cascaded energy storage capacitor; (b) is a structure diagram of an independent grounded energy storage capacitor; Figure 4 1 is a gate equivalent circuit diagram of an embodiment of the present invention; Figure 5 A simulation circuit diagram of a switch circuit with a series gate capacitor structure according to an embodiment of the present invention; Figure 6 1. The waveform diagram of each switch voltage of the series gate capacitor structure switch circuit according to an embodiment of the present invention; Figure 7 This is a structural diagram of a multi-channel optical fiber synchronization trigger circuit according to an embodiment of the present invention; Figure 8 1 is a voltage waveform diagram of the two-channel optical fiber receiver output according to an embodiment of the present invention; (a) is a voltage waveform diagram; (b) is a leading edge waveform diagram. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0027] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0028] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0029] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0030] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0031] In the description of the embodiments of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0032] The present invention is described in further detail below with reference to the accompanying drawings: See also Figure 1 The present application discloses a multi-channel synchronous optical fiber driven solid-state repetition rate pulse generator, including a drive control circuit, the drive control circuit is connected to a Marx generator, the Marx generator is provided with an AC-DC converter and several groups of IGBT switching circuits connected in series; the AC-DC converter is electrically connected to a group of IGBT switching circuits.

[0033] In some embodiments, the IGBT switching circuit includes an energy storage capacitor and an IGBT switch assembly; the energy storage capacitor and the IGBT switch assembly are connected in series, and the IGBT switch assembly is also provided with a charging resistor and a ground isolation resistor. In this topology, multiple series-connected IGBT switching circuits require only a single gate drive voltage signal to drive the bottommost IGBT switch assembly (i.e., Q0). The remaining IGBT switch assemblies are driven by the fully charged energy storage capacitors C1-C5 connected in series, thereby sequentially turning on in a very short period of time. Due to their rapid operation speed, the multiple series-connected IGBT switch assemblies in the entire IGBT self-triggering drive circuit can be considered to be driven synchronously. Based on this circuit structure, the modular design of multiple IGBT switch assemblies ensures that each IGBT switching circuit requires only a single drive signal, thereby reducing the number of drive circuits and making the circuit structure more compact.

[0034] Further preferably, the IGBT switch assembly is an insulated gate bipolar transistor, with a ground isolation resistor disposed between the drain and source of the IGBT; a charging resistor disposed between the gate and source, and a storage capacitor connected to the gate; a first group of IGBT switch circuits in the series connection is connected to a DC power supply; and a Zener diode is connected in reverse parallel between the gate and source of the IGBT. The IGBT is designed to have an insulation voltage exceeding 3kV, to achieve a higher withstand voltage and greater current capacity.

[0035] Further preferably, the series connection mode of the IGBT switch circuit includes: series energy storage capacitors, inter-polar cascade energy storage capacitors and independent grounded energy storage capacitors.

[0036] In some embodiments, the capacitance of the series energy storage capacitor is calculated by the following formula:

[0037]

[0038] Where, is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE poles of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the CG electrodes of the IGBT; is the voltage between the two GC levels of the first-level IGBT; is the energy storage capacitor of the i+1th level IGBT; The value of is 1, 2, ... n-1; n is the number of stages of the series-connected IGBT switching circuits.

[0039] In some embodiments, the capacitance of the independent grounded energy storage capacitor is calculated by the following formula:

[0040]

[0041] Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between CG of the IGBT; Capacitor The voltage on The value of is 2, 3, ... n-1; n is the number of groups of IGBT switching circuits connected in series.

[0042] In some embodiments, in the IGBT switch circuit with a gate-gated cascade connection, the capacitance values ​​of the energy storage capacitors are equal and are calculated using the following formula:

[0043] Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between CG of the IGBT; Capacitor The voltage on.

[0044] In some embodiments, the drive control circuit includes a signal generator, a drive circuit and an isolation module; the signal generator is connected to the drive circuit, the drive circuit is connected to the isolation module, the isolation module is electrically connected to a group of IGBT switch circuits, and the group of IGBT switch circuits is an IGBT switch circuit connected to an AC-DC converter; the isolation module includes an optical fiber isolation module and a voltage isolation module. In order to meet the overall isolation voltage requirements, the present application solution ensures that the optical transmitter and the optical receiver are connected through optical fiber to form an optical fiber isolation module, thereby maintaining a sufficient electrical isolation distance between the drive signal generator and the high-voltage circuit. The power supply end of the optocoupler adopts a DC-to-DC voltage isolation module (see Figure 7 , QA241) for further voltage isolation, thereby increasing the overall isolation voltage. Furthermore, in each level of the IGBT series module, the optocoupler's DC voltage charging terminal is equipped with a voltage isolation module to further achieve voltage isolation, ensuring stable and reliable operation of the entire circuit. Protected by multiple isolation schemes, this circuit structure can theoretically withstand even higher isolation voltages, making it suitable for driving higher-voltage switching circuits.

[0045] The present invention is a multi-channel synchronous optical fiber driven series IGBT solid-state high repetition rate pulse generator, see Figure 1 、 Figure 2The entire system comprises a main circuit consisting of a synchronous drive control circuit based on fiber-optic technology and a series IGBT switching circuit. In this topology, multiple series-connected IGBTs require only a single gate drive voltage signal to drive the bottom IGBT (i.e., Q0). The remaining IGBTs are driven by fully charged energy storage capacitors C1-C5, which are connected in series. Consequently, they are turned on sequentially within a very short period of time. Due to their rapid operation speed, the multiple series-connected IGBTs in the entire IGBT self-triggering drive circuit can be considered synchronously driven. This circuit structure allows for a modular design of multiple IGBT devices, requiring only a single drive signal per module. This reduces the number of drive circuits and makes the circuit structure more compact.

[0046] The control principle of this series IGBT topology is as follows: When the external drive signal for the bottom IGBT remains at a negative voltage, the bottommost IGBT (i.e., Q0) is off. The Zener diodes are in forward conduction, so the drive voltage for each IGBT is almost zero, and the entire series module remains off. During this process, each energy storage capacitor is charged via the resistor and the input high-voltage DC power supply. Furthermore, during the charging process, the charging resistor Ri ensures that the static voltage is evenly distributed across the series devices. In this case, the withstand voltage across the switch is determined by the total withstand voltage of the multiple IGBTs. Since the switch circuit is off, it does not affect the charging process of the energy storage capacitors in the Marx generator.

[0047] When the external drive signal becomes a stable positive voltage level, the IGBT switch Q0 is turned on first. At this time, the gate potential of Q0 will drop rapidly. During the rapid drop of potential, due to the potential isolation of the charging resistor R02, a gate-emitter voltage difference of the IGBT switch Q1 will be generated. Therefore, the equivalent capacitance C of Q1 GS1 The energy storage capacitor C1 will be charged. When the threshold voltage is reached, Q1 will turn on immediately. Similarly, the equivalent capacitance C of Q2 GS2 The capacitor C2 charges the IGBTs and turns on after reaching the threshold voltage. Consequently, the series-connected IGBTs will all reach the on-state in a very short period of time. From then on, the switch circuit remains in the on-state, with the on-state voltage being the sum of the on-state voltages of the multiple IGBTs.

[0048] When the IGBT switching circuit is in the on-state, maintaining the external drive signal at a positive voltage level ensures that Q0 remains in a stable on-state. During the triggering process, the gate-source capacitance of each IGBT switching component is charged, and all components are in the on-state. Therefore, unless there is an excessively large oscillating signal, the gate-emitter voltage difference of each IGBT switching component will be a nearly stable positive value, and all IGBT switching components can remain in a stable on-state. In this state, the energy storage capacitor in the Marx generator can discharge the load resistor in series through the switch.

[0049] When the external drive signal becomes negative again, the gate-emitter capacitance of Q0 begins to discharge, and Q0 begins to turn off. Simultaneously, the load current forces the gate-emitter capacitance of Q1-Q5 to discharge, allowing each IGBT to turn off synchronously. Furthermore, to prevent overvoltage damage to the IGBT caused by excessive voltage on the energy storage capacitor, a Zener diode is connected in reverse parallel between the GE terminals of the IGBT for protection.

[0050] The drive portion of this invention is based on fiber optic technology. The laser emitters at each stage of the multi-channel trigger circuit are connected in series. Therefore, the PWM signal from the signal generator, after passing through the NOT gate circuit, triggers the laser emitters to emit optical signals at nearly the same time. These optical signals are transmitted via optical fibers of equal length, ensuring that they arrive at their corresponding laser receivers synchronously. The laser receiver converts the information-carrying optical signal into an electrical signal. This electrical signal is then further amplified by an optocoupler and transmitted through a gate resistor to the gate of the first-stage IGBT in the IGBT series module.

[0051] Example In order to design a pulse generator that meets the requirements, the present invention consists of an optical fiber synchronous drive module and a series IGBT switching circuit. When a 20kV DC voltage is input, the DC voltage is charged to the energy storage capacitor through the primary circuit and distributed to the 6 IGBTs in the off state. Finally, the withstand voltage of each IGBT is about 3.33kV.

[0052] The IXEL40N400 insulated gate bipolar transistor has advantages such as high withstand voltage and strong current capacity. Therefore, the present invention selects the IXEL40N400 device as the switching device of the pulse generator.

[0053] The overall structural diagram of the pulse source system in this example is as follows Figure 1As shown in the figure, the pulse source system consists of a high-voltage main circuit section and a low-voltage drive control circuit section. The main structure of the high-voltage section is a Marx generator, which includes a DC power supply, a multi-stage IGBT series switch assembly, an energy storage capacitor, a charging resistor, and a ground isolation resistor. It can convert the input AC mains power into a high-voltage DC power supply through an AC-DC module, and then form a pulse output on the load resistor after energy storage and compression in the energy storage capacitor. The drive control circuit mainly consists of a signal generator, an optical fiber power supply isolation module, and a drive circuit. It is used to output the drive signal to each stage of the IGBT switch circuit while meeting electrical isolation requirements, so that it is synchronously turned on to achieve normal operation of the main circuit.

[0054] The circuit structure diagram of this example is as follows Figure 2 As shown. The working principle of the entire circuit is as follows: When the external drive signal becomes a stable positive voltage level, the IGBT switches Q 0 is turned on first. Q The gate potential of 0 will drop rapidly. In the process of rapid potential drop, due to R 2 potential isolation, will produce Q 1 gate emitter voltage difference. Therefore, Q 1 equivalent capacitance C GS1 The capacitor C 1 charging. When the threshold voltage is reached, Q 1 will open immediately. Q 2 equivalent capacitance C GS2 Energy storage capacitor C 2 is charged and turns on after reaching the threshold voltage. Therefore, the series-connected IGBTs will reach the on-state one by one in a very short period of time. After that, the switching circuit is in the on-state, and the on-voltage is the sum of the on-voltages of the multiple IGBTs.

[0055] When the IGBT switch circuit is in the on state, the external drive signal is kept at a positive voltage level to ensure Q During the triggering process, the gate-source capacitance of each IGBT is already charged, and all IGBTs are in the on state. Therefore, unless there is an excessively large oscillating signal, the gate-emitter voltage difference of each IGBT will be a nearly stable positive value, and all IGBTs can be in the stable on state. In this state, the energy storage capacitor in the Marx generator can be discharged in series with the load resistor through the switch.

[0056] There are many ways to select the circuit series, in addition to the series energy storage capacitor structure selected in this example (such as Figure 2 ), as well as isolation cascade energy storage capacitors and independent grounding energy storage capacitor structures (such as Figure 3 )wait.

[0057] To ensure consistent output waveforms, the value of the energy storage capacitor must be determined. This is crucial for ensuring that the switches can be turned on sequentially within a very short timeframe. Therefore, it's crucial to investigate the impact of the energy storage capacitor on the conduction behavior of series IGBT modules in various topologies. This circuit structure will explore the value of the energy storage capacitor and other key parameters for the three aforementioned topologies through theoretical analysis.

[0058] Since the capacitance of the Zener diode is much lower than that of the energy storage capacitor, its effect on the conduction of the switch can be ignored. However, the stray inductance is directly connected in series with the input capacitor, so this direct series relationship cannot be ignored. The device that has a greater impact on the circuit operation is retained in the approximate circuit. Therefore, after the next-stage switch is turned on, the gate equivalent circuit of the switch is as follows: Figure 4 shown.

[0059] Since the calculation of the energy storage capacitor value in the topology with independent grounding is the simplest, a theoretical calculation is performed first. The triggering process of the IGBT series module is the dynamic distribution process of charge from the energy storage capacitor of each IGBT to the gate-emitter capacitance, so the determination of each energy storage capacitor needs to follow the charge conservation principle. Therefore, the energy storage capacitor of the second layer (i.e., capacitor C 1) The formula is as follows:

[0060] Where, For the first-level IGBT (i.e. Q 0) The driving voltage between the two stages of GE, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the two GE stages of the IGBT, is the equivalent capacitance between the two CG stages of the IGBT.

[0061] because Much smaller than , so the energy storage capacitor C 1 can be obtained by approximate calculation.

[0062]

[0063] Similarly, other energy storage capacitors in the circuit can also be calculated according to the following formula.

[0064]

[0065] Where, The values ​​are 2, 3, 4, and 5.

[0066] Also, the voltage of the energy storage capacitor in this structure is:

[0067] From this, the capacitance values ​​of each level of energy storage capacitors can be obtained as follows:

[0068] Where, The values ​​are 2, 3, 4, and 5.

[0069] After substituting the specific parameter values ​​of the circuit, the capacitance values ​​of each energy storage capacitor in the topology structure with independent gate grounding can be obtained.

[0070] For the circuit structure of the inter-polar cascade energy storage capacitor, the energy storage capacitor values ​​at each level are equal. As long as the capacitance value meets the requirements of the energy storage capacitor C1 formula, the normal operation of the circuit can be achieved.

[0071] Furthermore, for circuit topologies with series storage capacitors, the formula for determining the storage capacitor differs from the above. Because the gate drive circuit loops of the switching devices are not independent, the charge transfer process of multiple storage capacitors must be considered. Therefore, the calculation formula for the storage capacitor is as follows.

[0072] (2-6) (2-7) Where, The values ​​are 1, 2, 3, 4, 5.

[0073] Based on the above calculation method and combined with the actual circuit device selection restrictions, taking the structure of 6 IGBTs in series as an example, the capacitance values ​​of energy storage capacitors in different topologies can be determined, as shown in Table 1.

[0074] Table 1 Values ​​of energy storage capacitors in various topological structures

[0075] There will be three topologies based on series energy storage capacitors, inter-polar cascade energy storage capacitors and independent grounded energy storage capacitors. The switching device is a single IGBT with a withstand voltage of 4.5kV. The total withstand voltage of each topology is 20kV. In order to leave a voltage margin, 6 switching devices are selected.

[0076] This embodiment selects a switch circuit based on a series energy storage capacitor structure. The simulation circuit diagram is as follows: Figure 5 , the voltage waveforms of the switches at each level are as follows Figure 6 As shown. The DC power supply voltage is 20kV, the power supply current limiting resistor R is 1kΩ, the load capacitor C is 47nF, and the load resistor RL The input drive signal amplitude is 15V and the pulse width is 4μs.

[0077] The results show that the theoretical withstand voltage of the IGBT module is as high as 20kV, and the pulse width and frequency can be flexibly adjusted, demonstrating good conduction consistency. Further test circuits were constructed, and the measured withstand voltage of the IGBT series switch circuit also reached 20kV, with a conduction time of 50ns and a pulse width adjustable within a range of 200ms. Multiple tests confirmed that the self-triggered conduction characteristics of the switch circuit are feasible and sufficiently stable.

[0078] At the same time, a multi-channel optical fiber synchronous trigger circuit is introduced, and the circuit structure is as follows: Figure 7 .

[0079] When the driving signal pulse width of the PWM signal generator input is 40ms and the repetition frequency is 20Hz, the voltage waveforms on the two optical fiber receivers are measured using a voltage probe as shown below: Figure 8 (a) shows the enlarged front edge of the square wave waveform. Figure 8 (b). Figure 8 As can be seen in (a), the output voltage of the laser receiver is 5V, with a repetition rate of 20Hz. The two waveforms have a high degree of overlap, with a time difference of less than 50ns, indicating that the voltage waveforms output by the two receivers are highly consistent.

[0080] And from Figure 8 As can be seen in (b), the signal difference between the voltage waveforms output by the two receivers is within 20 nanoseconds, while the switch's turn-on speed is on the order of hundreds of nanoseconds. Based on the circuit structure characteristics of this example, the fiber-triggered turn-on consistency is within 30 nanoseconds, preventing overvoltage failures in the IGBT switch circuit. Furthermore, the pulse rise edge of the drive signal is on the order of hundreds of nanoseconds, allowing it to turn on quickly enough to drive the next-stage optocoupler. Therefore, testing confirms that the driver module designed in this example does not affect the conduction characteristics of the pulse source's main circuit.

[0081] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A multi-channel synchronous fiber-driven solid-state repetition rate pulse generator, characterized in that: The drive control circuit includes a Marx generator connected thereto. The Marx generator includes an AC-DC converter and a plurality of IGBT switching circuits connected in series. The AC-DC converter is electrically connected to a group of IGBT switching circuits.

2. A multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 1, characterized in that: The IGBT switch circuit includes an energy storage capacitor and an IGBT switch component; the energy storage capacitor and the IGBT switch component are connected in series, and the IGBT switch component is also provided with a charging resistor and a ground isolation resistor.

3. The multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 2, characterized in that: The IGBT switch assembly is an insulated gate bipolar transistor, and a ground isolation resistor is arranged between the drain and source of the insulated gate bipolar transistor; a charging resistor is arranged between the gate and the source, and an energy storage capacitor is connected to the gate; and the first group of IGBT switch circuits in the series-connected IGBT switch circuits is connected to a DC power supply; a Zener diode is connected in reverse parallel between the gate and the source of the insulated gate bipolar transistor.

4. The multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 3, characterized in that: The series connection modes of IGBT switch circuit include: series energy storage capacitor, inter-pole cascade energy storage capacitor and independent grounded energy storage capacitor.

5. The multi-channel synchronous fiber-optic driven solid-state repetition rate pulse generator according to claim 4, characterized in that: In the series connection of the energy storage capacitors, the capacitance of the energy storage capacitor is calculated by the following formula: Where, is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE poles of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the CG electrodes of the IGBT; is the voltage between the two GC levels of the first-level IGBT; is the energy storage capacitor of the i+1th level IGBT; The value of is 1, 2, ... n-1; n is the number of stages of the series-connected IGBT switching circuits.

6. The multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 4, characterized in that: In the series connection of the independent grounded energy storage capacitors, the capacitance of the energy storage capacitor is calculated by the following formula: Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the two CG stages of the IGBT; Capacitor The voltage on The value of is 2, 3, ... n-1; n is the number of groups of IGBT switching circuits connected in series.

7. The multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 4, characterized in that: In the series connection of the inter-polar cascade energy storage capacitors, the capacitance values ​​of the energy storage capacitors are equal and are calculated by the following formula: Where, It is the energy storage capacitor of the first-level IGBT; is the driving voltage between the two GE levels of the first-level IGBT, is the voltage between the CE terminals of the IGBT when it is turned off, is the equivalent capacitance between the GE levels of the IGBT, is the equivalent capacitance between the two CG stages of the IGBT; Energy storage capacitor The voltage on.

8. The multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 1, characterized in that: The drive control circuit includes a signal generator, a drive circuit and an isolation module; the signal generator is connected to the drive circuit, the drive circuit is connected to the isolation module, and the isolation module is electrically connected to a group of IGBT switching circuits, which are IGBT switching circuits connected to an AC-DC converter; the isolation module includes an optical fiber isolation module and a voltage isolation module.

9. A control method for a multi-channel synchronous optical fiber driven solid-state repetition rate pulse generator, characterized in that: include: When the driving signal of the driving control circuit is maintained at a negative voltage level, several groups of IGBT switching circuits connected in series are disconnected; When the driving signal of the driving control circuit becomes a stable positive voltage level, several groups of IGBT switching circuits connected in series are turned on; When the driving signal of the driving control circuit changes from a stable positive voltage level to a negative voltage level, the plurality of groups of IGBT switching circuits connected in series are disconnected.

10. The control method of a multi-channel synchronous fiber-driven solid-state repetition rate pulse generator according to claim 9, characterized in that: The IGBT switching circuit includes an energy storage capacitor and an IGBT switching component, then: When the driving signal of the driving control circuit is maintained at a negative voltage level, in the plurality of groups of series-connected IGBT switch circuits, the IGBT switch components are disconnected and the energy storage capacitor is charged; When the driving signal of the driving control circuit becomes a stable positive voltage level, the energy storage capacitors in the series-connected IGBT switching circuits are discharged and the IGBT switching components are turned on; When the driving signal of the driving control circuit changes from a stable positive voltage level to a negative voltage level, the IGBT switch components in the plurality of groups of series-connected IGBT switch circuits are disconnected.

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