Energy-complementing resonant off-switching topology for multi-stage coil electromagnetic gun

Abstract

The application discloses a power compensation resonant turn-off topology for a multi-stage coil electromagnetic gun. The coil and switch module comprises a multi-stage accelerating circuit, each stage of the accelerating circuit comprising a switch unit and an oscillation coil connected in series; a resonant unit of an energy storage resonant module is connected to an energy storage unit, the energy storage resonant module comprising a positive electrode port and a negative electrode port respectively led out from two stages of the energy storage unit, and a resonant port led out from the resonant unit; a power bus comprises a positive bus connected to the positive electrode port, a negative bus connected to the negative electrode port, and a resonant bus connected to the resonant port; one end of two ends of each stage of the accelerating circuit is connected to the resonant bus, and the other end is connected to the positive bus or the negative bus. The application simultaneously realizes high power density and high energy density through a simple structure, and has the advantages of turn-off capacity, low cost and low volume and weight.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic launchers, and in particular to a power replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun. Background Technology

[0002] Coilguns use an energized coil to generate a magnetic field, which interacts with the projectile (armature) to produce an electromagnetic force, thus accelerating the projectile. There are two common types of coilguns: magnetic reluctance guns and induction guns. Magnetic reluctance guns accelerate the projectile through the attractive force between the coil and the ferromagnetic projectile, while induction guns induce a current in the projectile through a changing magnetic field. The repulsive force between the coil current and the induced current in the projectile accelerates the projectile. In multi-stage coilguns, a "stage" refers to the coil and its corresponding switches. Generally, a "stage" includes one coil (oscillating) and a set of switches.

[0003] This invention proposes a type of topology. In the field of coilgun research, topology refers to the connection method of each component in a pulse power circuit. The simplest topology uses one energy storage capacitor, one coil, and one switch in each stage, with these three components connected in series, for example:

[0004] [1] Zhang Wensheng, Qi Chao, Quan Yong, et al. Design of a three-stage coilgun firing system [J]. Electrical Measurement & Instrumentation, 2017, 54(14):7.

[0005] In slightly more complex topologies, a freewheeling diode is connected in parallel with the coil, for example:

[0006] [2] M.-G.Song, D.-V.Le, B.-S.Go, M.Park, and I.-K.Yu, “Design of anAttractive Force Circuit of Pulsed Power System for Multistage SynchronousInduction Coilgun,” IEEE Transactions on Plasma Science, vol.46, no.10, pp.3606–3611, Oct.2018, doi:10.1109 / TPS.2018.2827372.

[0007] [3]Z.Yadong, G.Yujia, 2019,doi:10.1109 / TPS.2019.2905044.

[0008] [4] A.Hassannia and K.Abedi, "Optimal Switching Scheme for MultistageReluctance Coilgun," IEEE Transactions on Plasma Science, vol.49, no.3, pp.1241–1246, Mar.2021, doi:10.1109 / TPS.2021.3061299.

[0009] These common topologies all face two fundamental contradictions:

[0010] (1) Energy density and power density of energy storage elements cannot be achieved simultaneously.

[0011] (2) The switching capability of a switching element and "low cost, size and weight" are mutually exclusive.

[0012] The reason for the contradiction (1) is that common high-energy-density energy storage elements, such as batteries, supercapacitors, and electrolytic capacitors, often have low power densities for coil guns. Common high-power-density energy storage elements, such as thin-film capacitors, oil-immersed capacitors, and ceramic capacitors, often have low energy densities. Therefore, energy storage elements often require a large volume and weight to simultaneously meet the energy and power requirements.

[0013] The reason for the contradiction (2) is that coilguns, especially those designs published in recent years, often improve their performance by using switching elements with interrupting capability (also called "open circuit switches"), as is the case in background literature [2-4]. However, open circuit switches often have poor withstand voltage and current resistance. Therefore, for high-power coilguns, a large number of open circuit switches are required to meet the power demand. This makes the cost, size, and weight of the switches larger. Switches without interrupting capability (also called "short circuit switches"), although they have stronger withstand voltage and current resistance and can be cheaper, smaller, and lighter, do not have interrupting capability as their name suggests, which is detrimental to the performance of the coilgun.

[0014] The book *Principles of Electric Guns* (Wang Ying, Xiao Feng, National Defense Industry Press, 1995) proposes a more ingenious and complex topology. It uses a resonant capacitor to drive the coil, generating a sinusoidal half-wave current through LC resonance. Therefore, a short-circuit switch can be used to achieve turn-off by utilizing the natural zero-crossing of the sinusoidal half-wave. An energy storage capacitor, a current-limiting inductor, and a single-phase thyristor (SCR) full-bridge are used to "recharge" the resonant capacitor. This topology design can resolve the two fundamental contradictions mentioned earlier to some extent; however, its topology structure also has the following drawbacks:

[0015] (1) Its structure is complex and requires more additional components. This increases costs and introduces additional losses, reducing efficiency.

[0016] (2) It targets "coilguns with discrete DC armature drives". These coilguns have complex structures and high projectile costs. For these reasons, they lack practical value, and no products based on this type of coilgun can be found in the public database. Summary of the Invention

[0017] The purpose of this invention is to address the aforementioned problems by providing a supplementary resonant shutdown topology for a multi-stage coil electromagnetic railgun, enabling the multi-stage coil electromagnetic railgun to simultaneously achieve high energy density and high power density, as well as shutdown capability, under a simple circuit structure.

[0018] The technical solution adopted in this invention is as follows:

[0019] A supplementary resonant shutdown topology for a multi-stage coil electromagnetic gun includes an energy storage resonant module, a power bus, and a coil and switch module; the coil and switch module includes a multi-stage acceleration circuit, and each stage of the acceleration circuit includes a set of oscillating coils whose current is controlled by a switch unit.

[0020] The energy storage resonant module includes an energy storage unit and a resonant unit. The resonant unit is connected to the energy storage unit. The energy storage resonant module includes a positive terminal port and a negative terminal port respectively led out from two stages of the energy storage unit, and a resonant port led out from the resonant unit.

[0021] The power bus includes a positive bus connected to the positive terminal, a negative bus connected to the negative terminal, and a resonant bus connected to the resonant terminal.

[0022] In each stage of the acceleration circuit, one end is connected to the resonant bus, and the other end is connected to either the positive bus or the negative bus.

[0023] The energy storage resonant module supplies energy to the coil and switching module through the power bus. The energy storage unit of the energy storage resonant module has high energy density and low power density, while the resonant unit has high power density and low energy density. The combination of the two to supply energy to the coil and switching module can simultaneously obtain the advantages of high power density and high energy density. This can reduce the cost, size and weight of the energy storage unit. At the same time, all acceleration circuits are connected to three sets of buses, eliminating the need for additional pulse power wiring and simplifying the circuit complexity.

[0024] Preferably, the energy storage unit includes two sets of energy storage modules connected in series, and the resonant unit includes three sets of resonant modules. One end of the three sets of resonant modules is connected in parallel, and the other end of the three sets of resonant modules is connected sequentially to the positive terminal, the negative terminal, and between the two sets of energy storage modules.

[0025] Of the two sets of energy storage modules, at most one set is a wire, and the remaining energy storage modules are energy storage elements;

[0026] Of the three sets of resonant modules, at least one set of resonant modules has a non-zero capacitance.

[0027] That is, the 0-1 group of energy storage modules in the energy storage unit can be replaced with short circuits, and the 0-2 group of resonant modules in the resonant unit can be replaced with open circuits.

[0028] Preferably, the switching unit in the acceleration circuit is connected in series with the oscillation coil.

[0029] Preferably, each group of power buses connects one end of the coil and the switch module, including a bidirectional conduction port, a unidirectional conduction port, or two unidirectional conduction ports with opposite conduction directions.

[0030] Preferably, the unidirectional conduction port is implemented by setting a diode.

[0031] Preferably, in each stage of the acceleration circuit, the switching unit of the acceleration circuit with bidirectional conduction ports at both ends has unidirectional conductivity.

[0032] Preferably, in each of the acceleration circuits, the switching unit of the acceleration circuit with one end connected to the unidirectional conduction port has unidirectional conductivity or bidirectional conductivity.

[0033] Preferably, the switching unit with unidirectional conductivity is a unidirectional conductive switching element or a bidirectional conductive switching element with a diode connected in series.

[0034] Preferably, the coil and switch module includes at least one stage of acceleration circuit, wherein the current direction of the acceleration circuit is from the resonant bus to the positive bus, or from the negative bus to the resonant bus.

[0035] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0036] 1. This invention combines a "high power density, low energy density resonant unit" with a "high energy density, low power density energy storage unit," simultaneously achieving the advantages of both "high power density" and "high energy density." This can reduce the cost, size, and weight of energy storage components.

[0037] 2. All switches in this invention can be short-circuit switches. The current crosses zero through LC resonance, allowing the switching unit to turn off naturally, thus achieving the advantages of "turn-off capability" and "low cost, size and weight".

[0038] 3. In this invention, all stages are connected to three sets of buses, eliminating the need for additional pulse power traces. Therefore, wiring is simple, cost-effective, and less prone to errors.

[0039] 4. This invention features only three sets of busbars between the "energy storage resonant module" and the "coil and switch module," making them structurally independent and easily placed in different locations. This results in a smaller size and weight for the "coil and switch module," which corresponds to the electromagnetic railgun's body. Therefore, electromagnetic railguns using this topology can more easily achieve a compact and lightweight body, making them more convenient for transport and rapid movement. Furthermore, if necessary, one of the "coil and switch" or "energy storage resonant module" can be quickly replaced without affecting the other components.

[0040] 5. This invention can use energy storage elements with lower voltages as energy storage units. High-energy-density energy storage elements generally have relatively low voltages; for example, the voltage of a single lithium battery and supercapacitor is only a few volts, and the maximum voltage of a single electrolytic capacitor is only around 500V. When flywheel energy storage uses a single electrode, the output voltage is also low. This invention, through energy-complementary resonance, can increase the voltage on the resonant unit (resonant capacitor) to several times the voltage of the energy storage element, allowing for the use of higher voltages to drive the coil. At the same power, increasing the voltage reduces the current. Lower current means thinner wires can be used, resulting in lower cost and manufacturing complexity. Attached Figure Description

[0041] The present invention will be described by way of example and with reference to the accompanying drawings, wherein:

[0042] Figure 1 This is a schematic diagram of the energy-supplementing resonant turn-off topology of the present invention.

[0043] Figure 2 This is the circuit schematic of the energy storage resonant module.

[0044] Figure 3 This is the circuit diagram of the acceleration bus.

[0045] Figure 4 This is the circuit schematic of the coil and switch module.

[0046] Figure 5 , Figure 7 , Figure 8 These are examples of three energy-compensating resonant turn-off topologies.

[0047] Figure 6 Yes Figure 5 The current and voltage curves recorded for the first 6 stages in the example test. Detailed Implementation

[0048] All features disclosed in this specification, or all steps in all disclosed methods or processes, may be combined in any way, except for mutually exclusive features and / or steps.

[0049] Any feature disclosed in this specification (including any appended claims and abstract) may be replaced by other equivalent or similar features, unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is merely one example of a series of equivalent or similar features.

[0050] Unless otherwise specified, the terms "first" and "second" used in this invention are merely to distinguish between objects that are not the same object, meaning that the attributes of the objects being described can be the same.

[0051] The energy-compensating resonant turn-off topology designed in this invention for a multi-stage coil electromagnetic railgun, such as... Figure 1 As shown, it includes three modules: an energy storage resonant module, a power bus, and a coil and switch module.

[0052] The energy storage resonant module comprises an energy storage unit and a resonant unit. The energy storage unit is a high-energy-density, low-power-density polarized energy storage element, which can be a polarized capacitor, such as an electrolytic capacitor or a supercapacitor, or other energy storage elements with high-power discharge capabilities, such as a non-polarized capacitor, a battery, or a flywheel, or a combination of these elements, such as a battery and a capacitor connected in parallel. Electrolytic capacitors are preferred as the energy storage unit. The resonant unit is a high-power-density, low-energy-density non-polarized resonant capacitor, such as a ceramic capacitor, a non-polarized electrolytic capacitor, a film capacitor, or an oil-immersed capacitor. Film capacitors are preferred as the resonant unit. The resonant unit is connected to the energy storage unit, and its two electrodes are not simultaneously connected in parallel to the two stages of the energy storage unit. The energy storage resonant module has three ports for each subsequent module: a positive port, a negative port, and a resonant port. The positive and negative ports are led out from the two stages of the energy storage unit, while the resonant port is led out from the stage of the resonant unit that is not connected to the energy storage unit. It should be noted that the polarity of the "positive port" and "negative port" here corresponds to the polarity of the energy storage unit.

[0053] In some embodiments, the energy storage unit includes two sets of energy storage modules connected in series, and the resonant unit includes three sets of resonant modules. One end of the three sets of resonant modules is connected in parallel, and the other end of the three sets of resonant modules is connected sequentially to the positive terminal, the negative terminal, and between the two sets of energy storage modules. Furthermore, among the two sets of energy storage modules, at most one set of energy storage modules is a wire (which can be understood as a short circuit), and the remaining energy storage modules are energy storage elements (i.e., there is a potential difference between the two ends). Among the three sets of resonant modules, at least one set of resonant modules has a non-zero capacitance, and a zero capacitance can be understood as an open circuit.

[0054] like Figure 2 The diagram illustrates an exemplary energy storage resonant module, which includes three resonant capacitors, labeled Cr1 to Cr3. It also includes two energy storage elements, represented by capacitor symbols and labeled C1 to C2. This energy storage resonant module is connected to the "power bus" through three ports (positive port, resonant port, and negative port), labeled "positive," "resonant," and "negative" respectively. Each of Cr1 to Cr3 can be a single capacitor or multiple capacitors connected in series and parallel. The capacitances of Cr1 to Cr3 do not need to be equal. One or both of Cr1 to Cr3 can be omitted, replacing them with an open circuit (which can also be considered a "capacitor with zero capacitance"). The capacitance and voltage rating of energy storage elements C1 and C2 do not need to be equal. Each of C1 and C2 can be a single energy storage element or multiple energy storage elements connected in series and parallel. One of C1 and C2 can be omitted, replacing it with a short circuit. The amount of charge that the energy storage element can provide during a single emission should be greater than the total charge of the resonant capacitor. The withstand voltage of the resonant capacitor should be higher than the maximum output voltage of the energy storage element, because during operation, the resonant capacitor will resonate and replenish energy, and its voltage will be higher than the voltage of the energy storage element.

[0055] The power bus consists of three sets of buses: a "positive bus," a "negative bus," and a "resonant bus." The positive bus connects to the positive terminal, the negative bus connects to the negative terminal, and the resonant bus connects to the resonant terminal. Each set of buses connects to the coil and the switching module, i.e., the end connecting the coil and the switching module. It includes one bidirectional conduction port, one unidirectional conduction port, or two unidirectional conduction ports with opposite conduction directions. This can be achieved by designing a set of buses to include one or two conductors and 0-2 sets of diodes. The diodes are used to achieve the unidirectional conduction capability of the conductors. Of course, when two sets of diodes are included, they are not placed on the same conductor. Specific designable structures will be described in detail below.

[0056] like Figure 3The diagram shown is a circuit schematic of a group of busbars. A busbar can be simply a single conductor, such as... Figure 3 As shown in (a), it can also be one or two wires with diodes, such as... Figure 3 As shown in (b)-(d).

[0057] Bidirectional and unidirectional conduction describe the direction of current flow. Regarding the conduction capacity of each port of the busbar, in Figure 3 In this diagram, the ports of various bus types are described using the suffixes B, P, and N. These ports are connected to the acceleration circuits at each stage in the coil and switching module. Port B indicates that the port is bidirectional, meaning current can both flow into and out of the port. Ports P and N indicate that the port is unidirectional; Port P indicates that current can only flow out of the port, and Port N indicates that current can only flow into the port. In subsequent embodiments describing the overall topology, the bus ports are distinguished by adding the suffixes "B / P / N" to "positive / resonant / negative" to differentiate the bus and its type.

[0058] The coil and switch module includes multiple stages of acceleration circuits, each stage of which can be simply referred to as a "stage". There is at least one stage, but in this embodiment of the invention, the number of stages is typically greater than two. For example... Figure 4 As shown, each stage of the acceleration circuit includes a set of oscillating coils whose switching states are controlled by a switching unit. This switching unit can be either a short-circuit switch or an open-circuit switch; both types are described in the background section. Specifically, a short-circuit switch is one where the control stage can only control when it is turned on, not when it is turned off; it can only turn off naturally after the current in it returns to zero. An open-circuit switch, on the other hand, has a turn-off capability. In this invention, a short-circuit switch is preferred, and subsequent embodiments are illustrated using a short-circuit switch as an example, but it is not excluded that an open-circuit switch could be used instead. The oscillating coil is used to generate a magnetic field to accelerate the projectile, and the short-circuit switch is connected in series with the oscillating coil to control the current in the oscillating coil.

[0059] Each stage (accelerator coil) has two ports. One port is connected to the resonant bus of the "power bus," and the other port is connected to either the positive or negative bus, depending on the conduction direction and purpose of that stage. If both ends of this stage are connected to a Class B bus (i.e., the bus with the port connected to the acceleration coil is a Class B port; the same applies to Class P and Class N later), then the short-circuit switch for this stage needs to be a switching element with unidirectional conductivity, such as a unidirectional thyristor or a thyristor, or a diode connected in series with a switching element with bidirectional conductivity. If one end of this stage is connected to a Class P or Class N bus, then in addition to the aforementioned switches with unidirectional conductivity (the switch conduction direction needs to match the current direction), switches with bidirectional conductivity, such as spark switches, vacuum trigger switches, and pseudo-spark switches, can also be used. Different types of switches can be used for each stage.

[0060] It is worth noting that the short-circuit switch connected to the oscillation coil can, in principle, be replaced with a switch with turn-off capability (open-circuit switch), that is, a switch that can control when to turn off, such as IGBT (Insulated Gate Bipolar Transistor), MOSFET, etc., but this is meaningless in terms of performance and is generally not used due to cost and size considerations, but this implementation method is not excluded.

[0061] Accelerator circuits can be divided into two categories based on their current direction: energy replenishment stages and voltage limiting stages. In the energy replenishment stage, the current direction is either "from the positive bus to the resonant bus" or "from the resonant bus to the negative bus." In the voltage limiting stage, the current direction is the opposite: "from the resonant bus to the positive bus" or "from the negative bus to the resonant bus." In the energy replenishment stage, the energy storage unit (energy storage element) provides energy to the resonant unit (resonant element), generally causing the voltage on the resonant unit to rise after discharge. In the voltage limiting stage, the resonant unit, in turn, charges the energy storage unit, causing the voltage on the resonant unit to drop. By inserting voltage limiting stages at appropriate locations—that is, by setting at least one voltage limiting stage in the topology—the voltage on the resonant unit can be controlled, improving the efficiency of converting energy from the energy storage unit into projectile kinetic energy.

[0062] In the field of electromagnetic railgun technology, or more generally in the field of pulse power technology, there are two fundamental contradictions:

[0063] (1) Energy density and power density of energy storage elements cannot be achieved simultaneously.

[0064] (2) The switching capability of a switching element and "low cost, size and weight" are mutually exclusive.

[0065] The most significant advantage of the topology proposed in this invention lies in its ability to simultaneously resolve these two major contradictions. That is:

[0066] (1) It can combine "high power density, low energy density resonant capacitors" with "high energy density, low power density energy storage elements" to obtain the advantages of both "high power density" and "high energy density". This can reduce the cost, size and weight of energy storage elements.

[0067] (2) The zero-crossing of the current through LC resonance allows the short-circuit switch to turn off naturally, thus achieving the advantages of "turn-off capability" and "low cost, size, and weight." Specifically, in the field of electromagnetic railguns, this advantage has the following effects:

[0068] This invention enables the recovery of residual magnetic energy from the coil. The magnetic circuit of a coilgun is relatively open and has a high magnetic field strength, resulting in much weaker coupling between the coil armature (projectile) compared to a typical electric motor. When accelerating the projectile, only a small portion of the magnetic energy is converted into kinetic energy. Even after the projectile leaves the coil, a significant amount of residual magnetic energy remains. Conventional coilgun topologies either cannot utilize this residual magnetic energy, leading to low efficiency and large size and weight of energy storage components, or require an "open-circuit switch," resulting in high cost and large size and weight of the switching components. This invention, through LC resonance, recovers the residual magnetic energy of the coil onto the resonant capacitor, enabling this energy to be reused in subsequent stages, improving efficiency; and it only requires a short-circuit switch, resulting in lower cost, size, and weight.

[0069] This invention reduces the reverse electromagnetic force (also called "pullback"). In a reluctance gun, the electromagnetic force generated by the coil is an attractive force. When the coil is in front of the projectile's direction of motion, the attractive force accelerates the projectile. When the coil is behind the projectile, the attractive force decelerates the projectile, i.e., pullback. To avoid pullback, the current in the coil needs to be eliminated before the projectile reaches the front of the coil. Conventional coil gun topologies either struggle to achieve this, leading to pullback and reduced efficiency, or require an "open circuit switch." This invention, through LC resonance, allows the current in the coil to naturally cross zero, thus eliminating the need for an "open circuit switch" and preventing pullback. Induction guns also have a similar problem: when the coil current is insufficient to maintain the rising magnetic field within the projectile, the induced current in the projectile reverses, and the electromagnetic force between the projectile and the coil changes from an accelerating repulsive force to a decelerating attractive force, i.e., pullback. In principle, if the current in the coil can be instantly reduced to zero, pullback can be eliminated. In practice, instantaneously reducing the current to zero is impossible, but the current waveform of this invention is a half-sine wave with a rapid decline, thus also reducing pullback.

[0070] Example 1

[0071] like Figure 5As shown, this embodiment discloses a supplementary resonant shut-off topology for a multi-stage coil electromagnetic railgun. Based on the circuit design of each module in this application, the energy storage resonant module in this embodiment omits the energy storage element C2 and the resonant capacitor Cr3. For the power bus section, all three bus groups use Class B buses. In the coil and switch module, a total of 6 stages are shown; more stages can be added, indicated by ellipses in the figure. All short-circuit switches are thyristors. In the figure, the oscillation coil of the nth stage is denoted as Ln, and the corresponding short-circuit switch is denoted as Qn, where n = 1, 2...N, and N is the total number of stages. Figure 5 In this system, level 4 is the pressure limiting level, while the other levels are energy replenishment levels. During operation, level 1 is the first to be switched on, and then each level is switched on sequentially according to its number.

[0072] This embodiment also tested the topology. Specifically, the parameters of this embodiment are as follows: all coils are 200uH inductors with a parasitic series resistance of 200mΩ; all switches are ideal thyristors, with the switches from stage 1 to stage 6 conducting in the 1st to 6th milliseconds respectively; resonant capacitors Cr1 and Cr2 are both 50uF in capacitance and have an initial voltage of 225V; the energy storage element C1 is a 1000uF capacitor with an internal resistance of 20mΩ and an initial voltage of 450V. C1 can be implemented using an electrolytic capacitor, which has the advantage of high energy density; Cr1 and Cr2 can be implemented using film capacitors, which have the advantage of high power density. This approach utilizes both advantages simultaneously to achieve high energy density and high power density.

[0073] like Figure 6 The figure shows the current and voltage curves recorded for the first six stages during testing of this topology. In the figure, the thin solid line represents the current from stage 1 to stage 6, the dotted line represents the voltage on the resonant bus, and the thick solid line represents the voltage on the energy storage capacitor.

[0074] from Figure 6 As the curves show, the current waveform at each stage is approximately a half-sine wave. Therefore, even using a "short-circuit switch" without turn-off capability, turn-off can be achieved by the current naturally crossing zero. The voltage amplitude of the resonant capacitor increases after the discharge of stages 1-3, reaching a maximum of 990V after the discharge of stage 3, significantly higher than the 450V of the energy storage capacitor. After stage 4, the voltage-limiting stage, some of the energy on the resonant capacitor is returned to the energy storage capacitor, and the voltage amplitude decreases, preventing the voltage from continuously rising and damaging the resonant capacitor. Subsequently, with the discharge of stages 5 and 6, the voltage on the energy storage capacitor begins to rise again.

[0075] Example 2

[0076] like Figure 7As shown, this embodiment discloses a supplementary resonant shut-off topology for a multi-stage coil electromagnetic railgun. Based on the circuit design of each module in this application, the resonant capacitors Cr1 and Cr2 are omitted in the energy storage resonant module in this embodiment. Regarding the power bus section, among the three bus groups, the positive bus is a P-type bus, with its unidirectional conduction direction determined by diode D1; the negative bus is an N-type bus, with its unidirectional conduction direction determined by diode D2; and the resonant bus is a B-type bus. In the coil and switch module, four stages are shown, all of which are supplementary energy stages. More stages can be added, indicated by ellipses in the figure. The short-circuit switches are all gas discharge switches with bidirectional conduction capability. In the figure, the oscillating coil of the nth stage is denoted as Ln, and the corresponding short-circuit switch is denoted as Gn, where n = 1, 2...N, and N is the total number of stages.

[0077] Example 3

[0078] like Figure 8 The diagram shows the energy replenishment resonant shutdown topology designed for a multi-stage coil electromagnetic railgun in Embodiment 3. Embodiment 3 is mainly used to illustrate the flexibility of the present invention.

[0079] Based on the circuit design of each module in this application, in this embodiment, the energy storage resonant module omits the energy storage element C2 and uses battery BT1 as the energy storage element C1, while omitting the resonant capacitor Cr2. For the power bus section, both the positive and negative buses use Class B buses. The negative two-channel resonant bus adopts a dual-wire structure, consisting of a Class P bus (whose unidirectional conduction direction is determined by diode D1) and a Class N bus (whose unidirectional conduction direction is determined by diode D2). Eight stages are shown in the figure, where stage 5 is the voltage limiting stage, and the other stages are energy replenishment stages. More stages can be added, indicated by ellipses in the figure. The switch for stage 1 is a bidirectional thyristor, denoted by Q1; the switches for stages 2 and 3 are unidirectional thyristors, denoted by Q2 and Q3 respectively; the switches for stages 4 to 8 are gas discharge switches, denoted by G4 to G8 respectively. The oscillation coils for each stage are denoted as Ln, where n = 1, 2…N, and N is the total number of stages.

[0080] This invention is not limited to the specific embodiments described above. The invention extends to any new feature or combination disclosed in this specification, as well as any new method or process step or combination disclosed herein.

Claims

1. A topology for energy replenishment resonant shutdown in a multi-stage coil electromagnetic railgun, characterized in that, This includes an energy storage resonant module, a power bus, and coil and switch modules; The coil and switch module includes a multi-stage acceleration circuit, and each stage of the acceleration circuit includes a set of oscillating coils whose current is controlled by a switching unit; the switching unit in the acceleration circuit is connected in series with the oscillating coil. The energy storage resonant module includes an energy storage unit and a resonant unit. The resonant unit is connected to the energy storage unit. The energy storage resonant module includes a positive terminal and a negative terminal led out from the two stages of the energy storage unit, and a resonant port led out from the resonant unit. The energy storage unit includes two sets of energy storage modules connected in series. The resonant unit includes three sets of resonant modules. One end of the three sets of resonant modules is connected in parallel, and the other end of the three sets of resonant modules is connected sequentially to the positive terminal, the negative terminal, and between the two sets of energy storage modules. In the two sets of energy storage modules, at most one set of energy storage modules is equivalent to a wire, and the remaining energy storage modules are energy storage elements. In the three sets of resonant modules, at least one set of resonant modules has a non-zero capacitance. The power bus includes a positive bus connected to the positive terminal, a negative bus connected to the negative terminal, and a resonant bus connected to the resonant terminal. In each stage of the acceleration circuit, one end is connected to the resonant bus, and the other end is connected to either the positive bus or the negative bus.

2. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 1, characterized in that, Each group of power buses connects one end of the coil and the switch module, including a bidirectional conduction port, a unidirectional conduction port, or two unidirectional conduction ports with opposite conduction directions.

3. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 2, characterized in that, The unidirectional conduction port is implemented by setting a diode.

4. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 2, characterized in that, In the acceleration circuits described at each stage, the switching unit of the acceleration circuit with bidirectional conduction ports at both ends has unidirectional conductivity.

5. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 2, characterized in that, In each of the acceleration circuits described, the switching unit of the acceleration circuit with one end connected to the unidirectional conduction port has unidirectional conductivity or bidirectional conductivity.

6. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 4 or 5, characterized in that, A switching unit with unidirectional conductivity can be either a unidirectional conductive switching element or a bidirectional conductive switching element with a diode connected in series.

7. The energy replenishment resonant shut-off topology for a multi-stage coil electromagnetic railgun as described in claim 1, characterized in that, The coil and switch module includes at least one stage of acceleration circuit, wherein the current direction of the acceleration circuit is from the resonant bus to the positive bus, or from the negative bus to the resonant bus.

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