BOOST topology and operation method of multi-stage coil electromagnetic gun

Abstract

The present invention discloses a BOOST topology structure and operating method for a multi-stage coil electromagnetic gun. The BOOST topology structure includes at least one BOOST topology network, which includes semiconductor switches and multi-stage acceleration circuits. Each stage of the acceleration circuit includes an energy storage unit, an acceleration coil, a level selection switch, a freewheeling diode, an energy recovery diode, and a charging diode. When the semiconductor switch and the level selection switch are turned on, the acceleration coil performs an excitation process. After the energy in the energy storage unit is depleted, the freewheeling diode automatically turns on, and the acceleration coil performs a freewheeling process. After that, the semiconductor switch is turned off, and the magnetic field energy of the acceleration coil is converted into electrical energy to charge the energy storage unit of the next level, thereby cycling each stage of the acceleration circuit. The present invention can achieve a highly integrated and efficient design for the electromagnetic gun, and with fewer semiconductor devices, achieves lightweight multi-stage electromagnetic guns.

Description

Technical Field

[0001] The present invention relates to the field of electromagnetic launchers, in particular to a BOOST topological structure of a multi-stage coil type electromagnetic gun, and an operating method of the corresponding topological structure. Background Art

[0002] There are two main types of electromagnetic guns, namely coil-type electromagnetic guns (hereinafter referred to as coil guns) and electromagnetic rail guns. Coil guns can be further divided into brush coil guns, induction coil guns, and magnetic resistance coil guns [1]. The coil of the coil gun is an important device for converting electrical energy into electromagnetic energy and kinetic energy. A pulsed current is passed through the coil to generate a pulsed magnetic field, which generates an electromagnetic force between the coil and the carrier (projectile) to achieve the acceleration effect.

[0003] Each type of coil gun (even rail gun) is derived from the common linear motor topology, and each type of coil gun has its corresponding linear motor [1]. Its acceleration structure is equivalent to the stator of the corresponding motor, and its accelerated projectile is equivalent to the corresponding mover.

[0004] In recent years, the rapid development of semiconductor technology, such as the invention and development of SCR, IGBT, MOS, etc., has also promoted the development of coil guns. However, the performance of coil guns made by simply using SCR as a switching device is not good [2]. Firstly, it is due to the problem of the circuit topology structure itself. The upper limit of the electric energy-kinetic energy conversion efficiency (hereinafter referred to as efficiency) is not high; secondly, it is limited by the performance of various components, such as the material of the projectile, the material of the winding coil, the energy storage density of the capacitor, the power capacity of the semiconductor switch, etc. The latter is difficult to make a leap forward in a short period of time. Only by reasonably transforming the former can the performance be significantly improved, such as the firing rate (the amount of projectiles fired per unit time), efficiency, the ratio of the projectile kinetic energy to the mass of the equipment (hereinafter referred to as the kinetic-mass ratio), etc.

[0005] In this regard, the present invention proposes a circuit topology suitable for coil guns based on the traditional BOOST converter technology [3].

[0006] [1] Wang Ying, Xiao Feng. Principles of Electric Gun. National Defense Industry Press, 1995, Section 1.4, Section 3.1.1.

[0007] [2] Fei Fucong, Li Yuancheng, Tang Yong, Lu Yuanyuan, Ni Guangyuan, Huang Xiaoqin. Fabrication and research of multi-stage magnetoresistive electromagnetic gun based on sensor control [J]. Physics and Engineering, 2013, 23(01): 25-28+35.

[0008] [3] Wu Zhidong. Research on a new type of high-voltage boost converter[J]. Electronic Measurement Technology, 2017, 40(03): 59-62. DOI: 10.19651 / j.cnki.emt.2017.03.013. Summary of the Invention

[0009] The object of the present invention is to address the above-mentioned problems and provide a BOOST topology structure of a multi-stage coil type electromagnetic gun, so as to improve the efficiency and integration of the multi-stage coil type electromagnetic gun at a lower cost through the design of the circuit topology structure, and promote the miniaturization and portable design of the electromagnetic gun.

[0010] The technical solution adopted in the present invention is as follows:

[0011] A BOOST topology structure of a multi-stage coil type electromagnetic gun includes at least one set of BOOST topology networks, wherein:

[0012] At least one group of the BOOST topology networks includes semiconductor switches and multi-stage acceleration circuits, wherein the semiconductor switches are fully controlled switches;

[0013] Each stage of the acceleration circuit includes an energy storage unit, an acceleration coil, a stage selection switch, a freewheeling diode and an energy recovery diode, wherein the stage selection switch is a half-controlled switch; the energy storage unit, the acceleration coil and the stage selection switch are connected in series and then connected to the semiconductor switch; the freewheeling diode is connected in parallel with the energy storage unit; the energy recovery diode of the non-final stage acceleration circuit is connected from the current stage acceleration coil to the next stage energy storage unit, and the energy recovery diode of the final stage acceleration circuit short-circuits the final stage acceleration coil, or connects the final stage acceleration coil to a varistor.

[0014] Preferably, the BOOST topology network consists of two or more groups, and the acceleration coils of each group of BOOST topology network are arranged in a staggered manner.

[0015] Preferably, the acceleration coils of each group of BOOST topology network are arranged in a staggered manner, including:

[0016] After the first-stage acceleration coils of each group of BOOST topology networks are arranged in sequence, each stage acceleration coil of each group of BOOST topology networks is arranged in the same sequence.

[0017] Preferably, each stage of the acceleration circuit further includes: a charging circuit, and the charging circuit is connected to the energy storage unit.

[0018] Preferably, the charging circuit includes a charging diode.

[0019] In view of the design of a single BOOST topology network, the present invention also provides an operation method of the BOOST topology structure of a multi-stage coil type electromagnetic gun, the method comprising:

[0020] Execute cyclically in the order of arrangement of the acceleration coils at each level:

[0021] turning on the semiconductor switch;

[0022] Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located;

[0023] After a specific time has passed, the semiconductor switch is turned off.

[0024] Preferably, the method further comprises:

[0025] After all the accelerating coils have completed one cycle of operation, the energy storage units of each level of the accelerating circuit are charged.

[0026] In view of the design of multiple groups of BOOST topology networks, the present invention also provides an operating method of the BOOST topology structure of a multi-stage coil type electromagnetic gun, which includes: controlling each group of BOOST topology networks to operate alternately.

[0027] Preferably, the controlling of the alternating operation of each group of BOOST topology networks includes:

[0028] Execute cyclically in the order of arrangement of the acceleration coils at each level:

[0029] Turn on the semiconductor switch of the BOOST topology network where the current stage acceleration coil is located;

[0030] Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located;

[0031] After a specific time has passed, the semiconductor switch is turned off.

[0032] Preferably, the method further comprises:

[0033] After all the accelerating coils have completed one cycle of operation, the energy storage units of each level of the accelerating circuit are charged.

[0034] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0035] 1. Each BOOST topology network of the present invention uses only one fully-controlled switch, and the multi-stage acceleration circuits all use half-controlled switches as the level selection switches. This greatly reduces the use of fully-controlled devices. In addition to significantly reducing costs, it also improves power capacity, allowing for greater power capacity at the same cost, or a smaller switch size at the same power capacity. Furthermore, the entire topology network uses fewer semiconductor components, minimizing energy loss in electronic components and facilitating the implementation of portable electromagnetic gun projects.

[0036] 2. The present invention utilizes the original characteristics of the BOOST circuit to recover the energy of the acceleration coil magnetic field, thereby achieving high-efficiency utilization of energy.

[0037] 3. The single-stage acceleration circuit of the present invention uses a small capacitor with almost no residual energy storage after each acceleration. The energy storage density utilization rate and efficiency are high, which is beneficial to reducing the volume and total energy storage of the energy storage device, and is beneficial to portability. The capacitor can be charged and stored while shooting, making continuous shooting possible and easily achieving a high shooting rate.

[0038] 4. The present invention utilizes a fully controlled device to directly control a semi-controlled device, so that the semi-controlled device has the characteristic of large power capacity while also having the function of "controllable shutdown", achieving the best of both worlds.

[0039] 5. The present invention realizes precise control of the acceleration timing and pulse width of each coil stage through full control devices, achieving "uniform acceleration" to achieve good acceleration effect, ensuring good acceleration performance such as better acceleration, efficiency and power-to-mass ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0041] Figure 1 The present invention is an embodiment of a BOOST topology structure of a multi-stage coil type electromagnetic gun including a single set of BOOST topology networks.

[0042] Figure 2 、 Figure 3 They are two embodiments of the BOOST topology structure of a multi-stage coil type electromagnetic gun including two groups of BOOST topology networks.

[0043] Figure 4 、 Figure 5 These are embodiments of driving circuits for a full-controlled switch and a half-controlled switch, respectively.

[0044] Figure 6-Figure 9 for Figure 3 Schematic diagram of the process of the first-stage accelerating coil operation in the embodiment.

[0045] Figure 10 For Figure 3 The test waveforms used to test the working process of the embodiment. DETAILED DESCRIPTION

[0046] All features disclosed in this specification, or all steps in the disclosed methods or processes, except mutually exclusive features and / or steps, can be combined in any manner.

[0047] Any feature disclosed in this specification (including any appended claims and abstract), unless otherwise stated, may be replaced by other equivalent or similar features. In other words, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0048] The terms “above” and “below” mentioned in the present invention include the current values.

[0049] Unless otherwise specified, the "first" and "second" mentioned in the present invention refer to this type of objects and do not distinguish or limit the physical characteristics of the described objects.

[0050] Example 1

[0051] This embodiment introduces the basic design concept of the BOOST topology of a multi-stage coil type electromagnetic gun.

[0052] The BOOST topology structure of the multi-stage coil electromagnetic gun of this embodiment includes a group of BOOST topology networks. In specific applications, the topology structure may include multiple groups of BOOST topology networks. Since the structures and operation methods of each group of BOOST topology networks are the same, this embodiment only uses one group of BOOST topology networks as an example to illustrate the basic design ideas.

[0053] The BOOST topology network includes semiconductor switches and multiple (two or more) stages of acceleration circuits. The semiconductor switches are fully controllable semiconductor switching devices (referred to as fully controlled switches, exhibiting the basic semiconductor device characteristic of unidirectional conduction). Each stage of the acceleration circuit includes an energy storage unit, an acceleration coil, a stage selection switch, a freewheeling diode, and an energy recovery diode. In this disclosure, the components of each stage of the acceleration circuit are referred to by their stage number. For example, the energy storage unit of the first-stage acceleration circuit is referred to as the first-stage energy storage unit, and so on. During operation, the energy storage unit contains initial energy storage, meaning it must be charged first. The stage selection switch is a semiconductor switching device with half-controllable capability (referred to as a half-controlled switch, also exhibiting unidirectional conduction). The energy storage unit, acceleration coil, and stage selection switch are connected in series and then connected to the semiconductor switch. The freewheeling diode is connected in parallel with the energy storage unit (with current flowing in the same direction). In this way, the stage selection switch directly controls the energization of the corresponding stage's acceleration coil. The semiconductor switch can directly control the switching off of each stage selection switch, thereby indirectly controlling the discharge of each stage's acceleration coil. As for the energy recovery diodes, except for the final-stage acceleration circuit, the energy recovery diodes of all other acceleration circuits connect from the current-stage acceleration coil to the energy storage unit of the next-stage acceleration circuit. This allows them to charge the energy storage unit of the next-stage acceleration circuit during the energy recovery phase while rapidly removing the magnetic field of the current-stage acceleration coil. The energy recovery diodes of the final-stage acceleration circuit short-circuit the final-stage acceleration coil (i.e., in the opposite direction of its discharge current, thus forming a loop) or connect the final-stage acceleration coil to a varistor to absorb the residual magnetic field energy of the acceleration coil.

[0054] by Figure 1Taking the BOOST topology network shown as an example, it includes a semiconductor switch Q1 and a three-stage acceleration circuit. The first-stage acceleration circuit includes an energy storage capacitor C1, an acceleration coil L1, a selector switch U1, a freewheeling diode D1, and an energy recovery diode D2. The energy storage capacitor C1 has initial energy storage and forms a basic circuit with the acceleration coil L1, the selector switch U1, and the semiconductor switch Q1. The freewheeling diode D1 short-circuits the energy storage capacitor C1. The energy recovery diode D2 is connected from the acceleration coil L1 to the energy storage capacitor C2 of the second-stage acceleration circuit. The second-stage acceleration circuit includes an energy storage capacitor C2, an acceleration coil L2, a selector switch U2, a freewheeling diode D3, and an energy recovery diode D4. The energy storage capacitor C2 has initial energy storage and forms a basic circuit with the acceleration coil L2, the selector switch U2, and the semiconductor switch Q1. The freewheeling diode D3 short-circuits the energy storage capacitor C2. The energy recovery diode D4 is connected from the acceleration coil L2 to the energy storage capacitor C3 of the third-stage acceleration circuit. The third-stage acceleration circuit includes an energy storage capacitor C3, an acceleration coil L3, a level selection switch U3, a freewheeling diode D5, and an energy recovery diode D6. The energy storage capacitor C3 has initial energy storage, and forms a basic circuit with the acceleration coil L3, the level selection switch U3, and the semiconductor switch Q1. The freewheeling diode D5 short-circuits the energy storage capacitor C3, and the energy recovery diode D6 is connected to the varistor RV1 via the acceleration coil L3. The energy storage capacitor C1, the acceleration coil L1, the level selection switch U1, the energy recovery diode D2, and the energy storage capacitor C2 form the framework of a traditional BOOST converter circuit. Figure 1 Based on the BOOST topology network shown, more acceleration circuits with the same structure as the first / second stage acceleration circuits can be designed between the second and third stage acceleration circuits, and the whole can include n levels (n=1, 2, 3, ...).

[0055] When each stage of the BOOST topology network's accelerating coil is in operation, there are three major processes: excitation, freewheeling, and energy recovery. The operating method of the BOOST topology structure of the multi-stage coil electromagnetic gun of this embodiment includes:

[0056] According to the arrangement order of the acceleration coils at each level, the following process is executed cyclically:

[0057] The semiconductor switch Q1 is turned on.

[0058] Then, the selector switch for the acceleration circuit where the current acceleration coil resides is turned on. If the current acceleration circuit is the first-stage acceleration circuit, selector switch U1 is turned on. At this point, the circuit formed by energy storage capacitor C1, acceleration coil L1, selector switch U1, and semiconductor switch Q1 is connected. Energy storage capacitor C1 charges acceleration coil L1, which begins to generate a magnetic field, accelerating the projectile. This is the excitation process. At this point, the magnetic field is just being established, and acceleration is relatively slow.

[0059] After the first excitation process, the energy of the energy storage capacitor of the current-stage acceleration circuit is exhausted, for example, the energy of the energy storage capacitor C1 is exhausted, the freewheeling diode D1 is naturally turned on, and the acceleration coil L1 automatically enters the freewheeling process. The projectile acceleration force reaches its peak and the speed increases rapidly. This process does not require any operation.

[0060] After the second freewheeling process, the projectile acceleration force will tend to drop sharply. At this time, when the semiconductor switch Q1 is turned off, the level selection switch of the current stage acceleration circuit will also be automatically turned off. For example, the above-mentioned level selection switch U1 will be automatically turned off, and the acceleration coil L1 will enter the energy recovery process. The residual magnetic field on it is converted into electrical energy, which is absorbed and stored by the energy storage capacitor C2 of the second stage acceleration circuit through the energy recovery diode D2.

[0061] In summary, based on the order of each stage's acceleration coils, the following cycle is repeated: semiconductor switch Q1 is turned on, then the selector switch for the acceleration circuit in which the current stage's acceleration coil resides is turned on. After a specified time (the first time + the second time described above), semiconductor switch Q1 is turned off. This cycle completes the BOOST topology of the multi-stage coil electromagnetic gun. Of course, in actual operation, after the energy storage capacitors at each stage are discharged, they must be recharged to recharge the acceleration coils. This is achieved structurally by connecting each energy storage capacitor to a charging circuit. Furthermore, after all acceleration coils have completed a cycle, the energy storage units in each stage's acceleration circuit are charged.

[0062] In the above-mentioned BOOST topology network, the semiconductor switch Q1 is a fully controlled switch, such as an IGBT or MOS tube. In addition to controlling the turn-off of each level selection switch U, it can also maintain the original characteristics of the BOOST topology network, so that it has an energy recovery function.

[0063] It's also important to note that while the BOOST topology is based on the theoretical foundation of a traditional BOOST converter circuit, it incorporates freewheeling diodes D1, D3, D5, and so on, D(2n-1). These diodes effectively protect the polarized energy storage capacitors (i.e., the energy storage unit) while also preventing negative voltage buildup in the capacitors and damaging electrical components through repeated operation. Furthermore, they provide the topology with a freewheeling function. Unlike traditional BOOST converters, the BOOST circuit used in coilguns incorporates a freewheeling process for the accelerator coil, which is crucial for improving coilgun efficiency. Freewheeling in the accelerator coil minimizes energy consumption, extending the duration of the high-intensity magnetic field and allowing the projectile to fully utilize the magnetic field's energy. The freewheeling and energy recovery processes in the accelerator coil enhance the coilgun's acceleration performance.

[0064] Each selector switch (U1, U2, ..., Un) is a semi-controlled switch, such as an SCR. This allows for the expansion of the number of acceleration circuits (primarily acceleration coils) in the BOOST topology network, selection of the acceleration circuits in operation, and the auxiliary freewheeling of the acceleration coils, thereby improving component utilization. Because SCRs can only be turned off at currents below their holding current (typically several hundred milliamperes), the turning off of semiconductor switch Q1 eliminates current flow through the selector switch, causing it to also turn off.

[0065] After the semiconductor switch Q1 is turned off, the network cleverly utilizes the characteristic of the acceleration coil (usually an inductor) that the current does not change suddenly, and the potential difference between the two energy storage capacitors to improve the recovery rate of the residual magnetic field energy of the acceleration coil (U=L di / dt, where L is the inductance of the acceleration coil; U is the potential difference between the two energy storage capacitors, and di / dt is the rate of decrease of the current when the semiconductor switch Q1 is turned off; so the larger U, the faster the current decreases), avoiding severe back-pull (deceleration) on the projectile, completing energy recovery and accelerating the removal of the coil's magnetic field.

[0066] In the final acceleration circuit, a varistor (RV1) is used to absorb the residual magnetic field energy of the acceleration coil. This achieves a current drop rate nearly identical to that achieved using a capacitor with initial energy storage, ensuring rapid elimination of the residual magnetic field. Its voltage-stabilizing properties also prevent surge voltages from being generated by the sudden disconnection of the acceleration coil, thereby protecting the semiconductor components. While the addition of a varistor can improve circuit performance, it is a preferred design feature, not a required one. Omitting the varistor or replacing it with another device with similar functionality does not affect the implementation of the present invention's design principles.

[0067] The above-described BOOST topology network is designed for a single group to illustrate its principle. With this understanding, one or more BOOST topology networks can be designed within a multi-stage electromagnetic gun to accelerate a projectile multiple times. During operation, only one acceleration coil can be selected for operation. The centers of adjacent acceleration coils within the same BOOST topology network cannot be too close. If this is too close, the lower coil can begin operating while the previous coil is in the freewheeling phase. Consequently, when the previous coil is in the energy recovery phase, the potential difference U between the two energy storage units is too small. As mentioned above, this results in slow energy recovery (i.e., slow current reduction), which can cause a backlash on the projectile and poor acceleration performance. This limitation does not apply to separate groups of acceleration coils. Designing a single BOOST topology network would hinder the compactness of the acceleration circuitry at each stage. When designing multiple BOOST topology networks, each network must operate alternately. This is because during the time it takes for the energy storage unit to discharge the acceleration coil, the projectile's displacement is likely to be greater than the length of the first-stage acceleration coil. Therefore, only one BOOST topology network can operate at a time.

[0068] Example 2

[0069] In this embodiment, the BOOST topology structure of the multi-stage coil electromagnetic gun is designed to include two groups of BOOST topology networks based on the same design principle as in the first embodiment. Of course, the structure can be expanded to include more groups of BOOST topology networks.

[0070] like Figure 2As shown, the first BOOST topology network includes a semiconductor switch Q1 and a three-stage acceleration circuit, which are: a first-stage acceleration circuit consisting of an energy storage capacitor C1, an acceleration coil L1, a level selection switch U1, a freewheeling diode D1 and an energy recovery diode D2; a second-stage acceleration circuit consisting of an energy storage capacitor C3, an acceleration coil L3, a level selection switch U3, a freewheeling diode D5 and an energy recovery diode D6; and a third-stage acceleration circuit consisting of an energy storage capacitor C5, an acceleration coil L5, a level selection switch U5, a freewheeling diode D9, an energy recovery diode D10 and a varistor RV1. The second BOOST topology network includes a semiconductor switch Q2 and a three-stage acceleration circuit. The three-stage acceleration circuits are: a fourth-stage acceleration circuit consisting of an energy storage capacitor C2, an acceleration coil L2, a level selection switch U2, a freewheeling diode D3, and an energy recovery diode D4; a fifth-stage acceleration circuit consisting of an energy storage capacitor C4, an acceleration coil L4, a level selection switch U4, a freewheeling diode D7, and an energy recovery diode D8; and a sixth-stage acceleration circuit consisting of an energy storage capacitor C6, an acceleration coil L6, a level selection switch U6, a freewheeling diode D11, an energy recovery diode D12, and a varistor RV2.

[0071] When physically arranging the BOOST topology of the multi-stage coil-type electromagnetic gun, in principle, it is sufficient to ensure that the center distance between two adjacent accelerating coils in the same BOOST topology network is sufficient. However, to rationally utilize space resources, the topology is designed to be as compact as possible, and the accelerating coils of each stage of the two BOOST topology networks are arranged in an interleaved manner, that is, arranged in the order of first stage, fourth stage, second stage, fifth stage, third stage, and sixth stage. Furthermore, during operation, the two BOOST topology networks are used alternately, while in a single BOOST topology network, the accelerating coils of each stage are operated sequentially, for example, the first BOOST topology network is operated in the order of first stage, second stage, and third stage, while the second BOOST topology network is operated in the order of fourth stage, fifth stage, and sixth stage. Specifically, the accelerating circuits of each stage are sequentially controlled to execute the excitation, freewheeling, and energy recovery processes according to the arrangement order of the aforementioned accelerating circuits, that is, the first stage is controlled to operate first, followed by the fourth stage, second stage, fifth stage, third stage, and sixth stage, and then back to the first stage, repeating the cycle.

[0072] Expanding to multiple BOOST topology networks, the accelerator coils of each level of the BOOST topology network are arranged in an interleaved pattern. During operation, each BOOST topology network is controlled to operate alternately. Furthermore, within each BOOST topology network, the accelerator coils of each level are controlled sequentially to operate. For example, in the simplest form, the first-level accelerator coils of each BOOST topology network are arranged sequentially, and then the accelerator coils of each level of the BOOST topology network are arranged sequentially in this order, that is, the second-level accelerator coils of each BOOST topology network are arranged in this order, the third-level accelerator coils of each BOOST topology network are arranged in this order, and so on. During operation, the accelerator coils of each level are operated sequentially according to the arrangement order. Of course, this is only the simplest form of interleaving. In addition, the interleaving can also be arranged in other order. For example, when arranging the second-level accelerator coils of each BOOST topology network, the arrangement does not follow the order of the first-level accelerator coils. As long as the acceleration coils of other groups of BOOST topology networks are arranged between two adjacent acceleration coils of the same group of BOOST topology networks, the acceleration coils can be as close as possible, or even close together, to achieve a compact design of the topology structure. If all the acceleration coils are finally close together, the most compact design of the topology structure can be achieved. After the acceleration circuits of multiple groups of BOOST topology networks are arranged in an interlaced manner, the order of arrangement of the acceleration coils at each level can be used to sequentially control the process of excitation, freewheeling, and energy recovery of the acceleration coils at each level. That is, according to the order of arrangement of the acceleration coils at each level, the following is executed cyclically:

[0073] Turn on the semiconductor switch of the BOOST topology network where the current stage acceleration coil is located;

[0074] Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located;

[0075] After a specific time, the semiconductor switch is turned off, shutting down the semiconductor switch in the BOOST topology network where the current acceleration coil is located. The next cycle begins with the next-order acceleration coil. After the last-order acceleration coil operates, the system returns to the first-order acceleration coil.

[0076] Example 3

[0077] This embodiment introduces another BOOST topology structure of a multi-stage coil electromagnetic gun in combination with the charging design of the energy storage capacitor. This embodiment also takes the design of two groups of BOOST topology networks as an example, and more groups of BOOST topology networks can be designed in the same way.

[0078] like Figure 3As shown, the BOOST topology structure of the multi-stage coil electromagnetic gun includes two groups of BOOST topology networks, wherein the first group of BOOST topology networks includes a semiconductor switch Q1 and 7 groups of acceleration circuits, which are: a first-stage acceleration circuit consisting of an energy storage capacitor C1, an acceleration coil L1, a level selection switch U1, a freewheeling diode D1 and an energy recovery diode D2; a second-stage acceleration circuit consisting of an energy storage capacitor C3, an acceleration coil L3, a level selection switch U3, a freewheeling diode D5 and an energy recovery diode D6; and a second-stage acceleration circuit consisting of an energy storage capacitor C5, an acceleration coil L5, a level selection switch U5, a freewheeling diode D9, an energy recovery diode D10 and a varistor RV1. The third-stage acceleration circuit; the fourth-stage acceleration circuit consisting of an energy storage capacitor C7, an acceleration coil L7, a level selection switch U7, a freewheeling diode D13 and an energy recovery diode D14; the fifth-stage acceleration circuit consisting of an energy storage capacitor C9, an acceleration coil L9, a level selection switch U9, a freewheeling diode D17 and an energy recovery diode D18; and the sixth-stage acceleration circuit consisting of an energy storage capacitor C11, an acceleration coil L11, a level selection switch U11, a freewheeling diode D21 and an energy recovery diode D22; the seventh-stage acceleration circuit consisting of an energy storage capacitor C13, an acceleration coil L13, a level selection switch U13, a freewheeling diode D25, an energy recovery diode D26 and a varistor RV1. The second BOOST topology network includes a semiconductor switch Q2 and six groups of acceleration circuits, which are: an eighth-stage acceleration circuit consisting of an energy storage capacitor C2, an acceleration coil L2, a level selection switch U2, a freewheeling diode D3, and an energy recovery diode D4; a ninth-stage acceleration circuit consisting of an energy storage capacitor C4, an acceleration coil L4, a level selection switch U4, a freewheeling diode D7, and an energy recovery diode D8; and a ninth-stage acceleration circuit consisting of an energy storage capacitor C6, an acceleration coil L6, a level selection switch U6, a freewheeling diode D11, and an energy recovery diode D12. The tenth-stage acceleration circuit consists of a storage capacitor C8, an acceleration coil L8, a selector switch U8, a freewheeling diode D15, and an energy recovery diode D16; the eleventh-stage acceleration circuit consists of a storage capacitor C10, an acceleration coil L10, a selector switch U10, a freewheeling diode D19, and an energy recovery diode D20; and the thirteenth-stage acceleration circuit consists of a storage capacitor C12, an acceleration coil L12, a selector switch U12, a freewheeling diode D23, an energy recovery diode D24, and a varistor RV2. Semiconductor switches Q1 and Q2 are fully controlled switches, while selector switches U1-U13 are half-controlled switches.

[0079] During physical layout, the accelerating coils are arranged in the order L1, L2, L3, ..., L13. During operation, each stage of the accelerating coils is controlled sequentially according to this arrangement, executing the excitation, freewheeling, and energy recovery processes. In this implementation, the two BOOST topology networks are controlled to operate alternately, with each BOOST topology network operating sequentially.

[0080] After the energy storage capacitor is discharged, it needs to be charged before the secondary cycle. To this end, a charging circuit is connected to the energy storage capacitor of each stage of the acceleration circuit. The charging circuit has unidirectional conductivity. After all the charging circuits are connected in parallel, they are connected to the power supply through the charging switch. The charging circuit is used to charge all the energy storage capacitors. In some embodiments, Figure 3 As shown, the charging circuit primarily includes a charging diode (or isolation diode). Energy storage capacitors C1, C2, ..., C13 are connected to charging diodes DB1, DB2, ..., DB13, respectively. Charging diodes DB1-DB13 are connected in parallel and connected to the high-voltage power supply VCC via switch SW1. Switch SW1 controls whether the high-voltage power supply charges the energy storage capacitors. Due to the unidirectional conductivity of each charging diode DB1-DB13, they isolate the discharge of each energy storage capacitor C1, C2, ..., C13, eliminating the need for separate switching elements in each charging circuit.

[0081] The control of topological structure operation is actually the control of corresponding switching devices. Figure 3 As shown, the corresponding semiconductor switches Q1, Q2, and the level selection switches U1, U2 ... U13 are driven by the corresponding driving voltage NETx (x = 1, 2, 3 ... 15), and the corresponding driving voltage is determined by Figure 4 、 Figure 5 The driving circuit (example) shown is provided (due to strong repetitiveness, only some examples are provided, the driving voltage of NET7~NET13 is referenced Figure 5 The driving circuit can be obtained), where Figure 4 It is the driving circuit of the full-control switch. Figure 5 This is a driving circuit for a half-controlled switch. The device models used in this embodiment are shown in Table 1 below.

[0082]

[0083] Table 1

[0084] H16 and H17 are isolated 12V to 20V power supplies for the suspension drive. MCU1 through MCU15 (the drive circuits for U7 through U13 are identical to those for U1 through U6; due to their high repetitiveness, MCU7 through MCU13 are not shown in this article) are connected to the 15 different I / O ports of the STC89C52RC microcontroller to control the on and off of the various semiconductor switches. (Note that the drive signals for semiconductor switches Q1 and Q2 are long-pulse square wave pulses, while the drive signals for selector switches U1 through U13 are short-pulse square wave pulses.)

[0085] like Figure 6-Figure 9 FIG. 1 is a schematic diagram of the current when the first-stage accelerating coil is controlled to operate according to this embodiment.

[0086] like Figure 6 As shown, the semiconductor switch Q1 is turned on, and the level selection switch U1 is turned on at this time. The energy storage capacitor C1 supplies energy to the acceleration coil L1. The acceleration coil L1 performs the excitation process and enters the magnetic field construction stage. In this stage, the projectile is slowly accelerated.

[0087] like Figure 7 As shown in the figure, after the first excitation time, the energy of the energy storage capacitor C1 is exhausted, the freewheeling diode D1 is naturally turned on, and the acceleration coil L1 enters the freewheeling process. During this process, the projectile acceleration force reaches its peak and the speed increases rapidly.

[0088] like Figure 8 As shown, after the second freewheeling time, the projectile's acceleration force tends to drop sharply. At this time, semiconductor switch Q1 is turned off (due to Q1's shutdown, U1 is also turned off), and acceleration coil L1 enters the energy recovery process, allowing the residual magnetic field to be quickly eliminated to avoid severe back-pull (deceleration) on the projectile. Acceleration coil L1 converts the residual magnetic field energy into electrical energy, which is absorbed and stored by the next-level energy storage unit C3 in preparation for the next acceleration.

[0089] like Figure 9 As shown, after the first stage acceleration coil of the first group of BOOST topology network has finished working, the semiconductor switch Q2 and the level selection switch U2 are turned on, and the first stage acceleration coil of the second group of BOOST topology network (corresponding to the eighth stage acceleration coil in the previous text) continues to work. The working process is the same as Figure 6-8 The following steps are to control the acceleration coils of each level in the order of the second level, the ninth level, the third level, the tenth level, and so on. The operation process of each level of acceleration coil is the same as that of the first level.

[0090] This embodiment conducts actual testing of the aforementioned process. After energy storage capacitors C1-C13 are charged to 400 volts, SW1 is disconnected. The projectile is cylindrical, with specifications of 8 mm diameter, 20 mm length, and 7.8 g, and is made of A3 steel according to the national standard GB119. The barrel is made of 304 stainless steel, with specifications of 8.1 mm inner diameter and 8.5 mm outer diameter. The projectile's initial position is -15.5 mm (i.e., before the coilgun operates, the distance between the projectile center and the center of the first-stage acceleration coil is 15.5 mm, and the projectile is behind the first-stage acceleration coil). Table 2 below shows the driving schedule for each semiconductor switch and selector switch for a single firing process (one cycle of acceleration coils L1-L13). Table 3 shows the specifications of each stage of the acceleration coil. Figure 10 To correspond to this experiment, Ansys Electronics 2021 R2 was used to test the relevant objects and draw the test waveforms, where the red line ( l1 ) is the force condition of the projectile, and the light green line ( l2 ) is the velocity of the projectile, and the remaining lines are the discharge conditions of the corresponding accelerating coils. Figure 10 It can be seen that the projectile is in an almost uniform acceleration state, reaching 112 m / s over an acceleration length of about 24 cm, showing a good acceleration state. In addition, for this embodiment, the total mass of the entire topological structure is about 1280 grams.

[0091]

[0092] Table 2

[0093]

[0094] Table 3

[0095] In summary, when the BOOST topology structure of the multi-stage coil electromagnetic gun includes two or more BOOST topology networks, the accelerating coils of each BOOST topology network must also be staggered. As for its operation method, the principle is the same as that of the second embodiment, except that the number of accelerating coils is greater, namely, including:

[0096] According to the arrangement order of the acceleration coils at each level, the following is executed cyclically:

[0097] Turn on the semiconductor switch of the BOOST topology network where the current stage acceleration coil is located;

[0098] Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located;

[0099] After a specific time, the semiconductor switch is turned off, that is, the semiconductor switch of the BOOST topology network where the current stage acceleration coil is located is turned off.

[0100] Because this embodiment also takes into account the charging process of the energy storage units, the operating method further includes: charging the energy storage units of each stage of the acceleration circuit after all acceleration coils complete a cycle. That is, after each cycle of excitation, freewheeling, and energy recovery for all acceleration coils, the energy storage units of each stage are charged. Specifically, following the above operating method, when the current stage is the last stage of the acceleration coil and the cycle has completed, that is, after the last stage selection switch is turned on and the semiconductor switch is turned off, the charging switch is closed, and the power supply charges each energy storage unit. After a third time has passed, the power supply completes charging of each energy storage unit. At this point, the charging switch is disconnected, and the above cycle is repeated, starting with the first stage of the acceleration coil.

[0101] Because this invention can be precisely controlled using an MCU, it offers the advantages of high firing rate and controllable speed. Operating modes can be selected according to actual needs, with power and firing rate adjusted with a single click. To safely expel living people or animals, a high-rate, low-power mode can be switched. Once further breakthroughs in the performance of various components are achieved, integration and power-to-mass ratios can be further improved. In the future, this device has the potential to be used as a kinetic weapon in individual combat situations, and even in anti-missile systems, shipboard systems, and coastal defense systems.

[0102] The present invention is not limited to the aforementioned specific embodiments, but can be extended to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A BOOST topology structure of a multi-stage coil electromagnetic gun, characterized in that: It includes at least one set of BOOST topology networks, where: At least one group of the BOOST topology networks includes semiconductor switches and multi-stage acceleration circuits, wherein the semiconductor switches are fully controlled switches; Each stage of the acceleration circuit includes an energy storage unit, an acceleration coil, a stage selection switch, a freewheeling diode and an energy recovery diode, wherein the stage selection switch is a half-controlled switch; the energy storage unit, the acceleration coil and the stage selection switch are connected in series and then connected to the semiconductor switch; the freewheeling diode is connected in parallel with the energy storage unit; the energy recovery diode of the non-final stage acceleration circuit is connected from the current stage acceleration coil to the next stage energy storage unit, and the energy recovery diode of the final stage acceleration circuit short-circuits the final stage acceleration coil, or connects the final stage acceleration coil to a varistor.

2. The BOOST topology structure of the multi-stage coil type electromagnetic gun according to claim 1, characterized in that: The BOOST topology network consists of two or more groups, and the acceleration coils of each group of BOOST topology network are arranged in a staggered manner.

3. The BOOST topology structure of the multi-stage coil type electromagnetic gun according to claim 2, characterized in that: The acceleration coils of each BOOST topology network are arranged in an interlaced manner, including: After the first-stage acceleration coils of each group of BOOST topology networks are arranged in sequence, each stage acceleration coil of each group of BOOST topology networks is arranged in the same sequence.

4. The BOOST topology structure of the multi-stage coil type electromagnetic gun according to claim 1, characterized in that: Each stage of the acceleration circuit further includes a charging circuit connected to the energy storage unit.

5. The BOOST topology structure of the multi-stage coil type electromagnetic gun according to claim 4, characterized in that: The charging circuit includes a charging diode.

6. The method for operating the BOOST topology structure of a multi-stage coil type electromagnetic gun according to claim 1, wherein the BOOST topology structure of the multi-stage coil type electromagnetic gun comprises a set of BOOST topology networks, characterized in that: Methods include: Execute cyclically in the order of arrangement of the acceleration coils at each level: turning on the semiconductor switch; Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located; After a specific time has passed, the semiconductor switch is turned off.

7. The operation method according to claim 6, characterized in that: Also includes: After all the accelerating coils have completed one cycle of operation, the energy storage units of each level of the accelerating circuit are charged.

8. The method for operating the BOOST topology structure of the multi-stage coil electromagnetic gun according to claim 2, wherein: include: Control the alternating operation of each group of BOOST topology networks.

9. The operation method according to claim 8, characterized in that: The controlling of the alternating operation of each group of BOOST topology networks includes: Execute cyclically in the order of arrangement of the acceleration coils at each level: Turn on the semiconductor switch of the BOOST topology network where the current stage acceleration coil is located; Turn on the level selection switch of the acceleration circuit where the current level acceleration coil is located; After a specific time has passed, the semiconductor switch is turned off.

10. The operation method according to claim 9, characterized in that: Also includes: After all the accelerating coils have completed one cycle of operation, the energy storage units of each level of the accelerating circuit are charged.

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