A high-field magnetic system

Abstract

The application belongs to the technical field of pulsed high magnetic field, and particularly discloses a high magnetic field system. The control module provides a reset signal for a magnetic switch reset circuit and provides a trigger signal for an RSD pre-trigger circuit. The RSD pre-trigger circuit triggers the conduction of the RSD reverse charging after receiving the trigger signal. The discharge main circuit feeds the single-turn coil with a pulse current with an amplitude higher than a preset threshold and a current rise rate after the magnetic switch is saturated and the RSD reverse charging, and then generates a high magnetic field in the single-turn coil. The application can generate a high-amplitude magnetic field in the single-turn coil repeatedly for multiple times.

Description

Technical Field

[0001] The present application belongs to the field of pulsed high-intensity magnetic field technology, and more specifically, relates to a high-intensity magnetic field system. Background Art

[0002] Destructive pulsed magnetic fields eliminate the need for magnet reuse, reinforcement, or heat dissipation. Compared to non-destructive high-intensity magnetic fields, their overall circuit structure is significantly simplified, enabling higher peak magnetic field strengths. A single-turn coil is a mainstream destructive pulsed magnetic field. Previous experimental data indicates that a destructive pulsed high-intensity magnetic field system can generate peak magnetic fields of 100T-300T within a single-turn coil. A single-turn coil consists of a single turn of metal coil. When discharged, a high current with a pulse width of several microseconds and a peak current of several million amperes can generate an extremely strong magnetic field exceeding 100T.

[0003] The discharge circuit using a single-turn coil as the load has a simple structure, essentially equivalent to a second-order RLC circuit. The main control switch in a conventional discharge circuit is typically a gas switch. When the gas switch is closed, the main capacitor discharges the single-turn load coil, generating a high-amplitude pulsed magnetic field at the center of the single-turn coil. Gas switches offer advantages such as high voltage resistance and a high current rise rate. However, gas switches have a short lifespan, are limited to a single discharge, and have a current limit of approximately 100kA. To generate an extremely strong magnetic field of several hundred tesla, the peak current in the main circuit during discharge will reach 1-3mA, and the current rise rate of the single-turn coil will reach the mA / μs level. To achieve this performance, a single-turn coil-based destructive magnetic field system using gas switches requires approximately ten gas switches in parallel. However, current gas switch activation jitter is significant, accounting for almost half of the discharge rising edge. Consequently, single-turn coil-based destructive magnetic field systems using gas switches as the main switch suffer from high cost, large charge transfer during discharge, short switch lifespan, and significant jitter when multiple gas switches are used in parallel, which is difficult to address. Summary of the Invention

[0004] In response to the defects of the existing technology, the purpose of this application is to provide a strong magnetic field system, which aims to solve the problem that the single-turn coil destructive strong magnetic field system using a gas switch as the main switch requires multiple gas switches to achieve a high-amplitude magnetic field, so there is huge jitter when multiple gas switches are used in parallel, resulting in a long instantaneous discharge rising edge time and high cost.

[0005] To achieve the above objectives, in a first aspect, the present application provides a strong magnetic field system, including a discharge main circuit, an RSD (Reversely Switched Dynistor) pre-trigger circuit, a magnetic switch reset circuit, and a control module;

[0006] The output end of the control module is connected with a magnetic switch reset circuit and an RSD pre-trigger circuit; a demagnetizing coil in the magnetic switch reset circuit is wound on the magnetic switch; and the RSD pre-trigger circuit is connected across the RSD in the discharge main circuit.

[0007] The discharge main circuit comprises a main capacitor, a magnetic switch, an RSD and a single-turn coil; the anode of the RSD is connected with the anode of the main capacitor through the magnetic switch; and the cathode of the RSD is connected with the cathode of the main capacitor through the single-turn coil.

[0008] The control module is configured to provide a reset signal for the magnetic switch reset circuit and a trigger signal for the RSD pre-trigger circuit; the reset signal is configured to control the current to flow through the demagnetizing coil in the magnetic switch reset circuit to generate a demagnetizing magnetic field in the magnetic core of the magnetic switch for resetting; the RSD pre-trigger circuit is configured to trigger the RSD to conduct after receiving the trigger signal; and the discharge main circuit is configured to feed a pulse current with an amplitude higher than a preset threshold and a current rise rate into the single-turn coil after the magnetic switch is saturated and the RSD is reversely charged, so as to generate a strong magnetic field in the single-turn coil.

[0009] Further preferably, to withstand the high-amplitude pulse current in the discharge main circuit, the anode of the RSD is connected with the anode of the main capacitor through a copper bar passing through the magnetic switch; the cathode of the main capacitor is connected with one end of the single-turn coil through a copper bar, and the other end of the single-turn coil is connected with the cathode of the RSD through a copper bar.

[0010] Further preferably, the magnetic switch is a ring structure composed of a magnetic core and an outer layer of the magnetic core pressed with epoxy, and the through-flow copper bar of the main capacitor passes through the magnetic switch.

[0011] Further preferably, the single-turn coil comprises a magnet coil and two electrode plates; the magnet coil is a single-turn wire, and the two ends of the magnet coil are welded to the outer surfaces of the two electrode plates; and the two electrode plates are two parallel metal plates.

[0012] Further preferably, according to the actual current peak value, voltage resistance and high current rise rate, a plurality of RSDs are arranged in series and parallel combination, a plurality of groups of RSDs correspond to a plurality of copper bars, and the two ends of the single-turn coil are connected with one copper bar respectively, and the plurality of copper bars are connected with one copper bar at one end of the single-turn coil through an adapter.

[0013] In a second aspect, based on the strong magnetic field system, the application provides a corresponding strong magnetic field acquisition method, which specifically comprises the following steps:

[0014] Based on the reset signal, the reset operation is performed on the magnetic switch, so that the magnetic material in the magnetic switch is at the negative saturation point of the magnetic hysteresis loop, and the magnetic switch is equivalent to a circuit breaker, which isolates the RSD from the main capacitor voltage;

[0015] The main capacitor is charged by using a main capacitor charging power supply, and the RSD pre-trigger capacitor is charged by using an RSD pre-trigger capacitor charging power supply.

[0016] When the main capacitor and the RSD pre-trigger capacitor are charged, based on a trigger signal, the RSD pre-trigger circuit is controlled to be closed, so that the RSD pre-trigger capacitor reversely charges the RSD, for the RSD pre-trigger stage;

[0017] When the RSD pre-trigger capacitor reversely charges the RSD to a degree that meets the actual demand, and the magnetic switch is saturated and turned on, the main capacitor discharges to the single-turn coil through the magnetic switch and the RSD,

[0018] The single-turn coil is fed with a pulse current with an amplitude higher than a preset threshold and a current rise rate, so as to generate a strong magnetic field in the center of the single-turn coil.

[0019] Further preferably, in the RSD pre-trigger stage, the main capacitor applies a forward voltage to the magnetic switch, the magnetic switch is moved from the negative saturation point of the hysteresis loop to the positive saturation point of the hysteresis loop, the inductance of the magnetic switch changes from large to small, and after the positive saturation, the magnetic switch is equivalent to a short circuit, the magnetic switch is turned on, the main capacitor discharges, and a strong magnetic field is generated in the center of the single-turn coil.

[0020] Overall, compared with the prior art, the above technical solutions conceived by the present application have the following beneficial effects:

[0021] The strong magnetic field system provided by the present application introduces a semiconductor RSD into the strong magnetic field system, the RSD is a new type of high-power pulse semiconductor with strong current-carrying capacity and high current rise rate. Therefore, the single-turn coil type destructive strong magnetic field system of the present application can better achieve the goal of passing through a current with a higher amplitude and a higher rise rate in the main discharge circuit, thereby generating a stronger magnetic field in the single-turn coil. Compared with the destructive pulse strong magnetic field system using multiple gas switches in parallel, the structure of the present application is simpler, the system occupies a smaller space volume, can repeatedly discharge to generate a high-amplitude magnetic field in the single-turn coil, and has a reduced cost. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a strong magnetic field system structure schematic diagram provided by an embodiment of the present application;

[0023] Figure 2 is a strong magnetic field system structure schematic diagram based on a specific RSD pre-trigger circuit provided by an embodiment of the present application;

[0024] Figure 3 is a single-turn coil structure schematic diagram provided by an embodiment of the present application;

[0025] Figure 4 is a main circuit line current schematic diagram during discharge provided by an embodiment of the present application;

[0026] Figure 5This is a schematic diagram of the central magnetic field simulation of a single-turn coil provided in an embodiment of the present application. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0028] The term "and / or" as used herein describes an association between related objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. The symbol " / " as used herein indicates that the related objects are in an "or" relationship, for example, A / B means either A or B.

[0029] The terms "first" and "second" and the like in the description and claims herein are used to distinguish different objects rather than to describe a specific order of the objects.

[0030] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0031] In the description of the embodiments of the present application, unless otherwise specified, “plurality” means two or more.

[0032] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0033] like Figure 1 As shown, the present application provides a strong magnetic field system, including a discharge main circuit, an RSD (Reversely Switched Dynistor) pre-trigger circuit, a magnetic switch reset circuit and a control module; the magnetic switch reset circuit is used to reset the magnetic switch; the RSD pre-trigger circuit is used to reverse charge the RSD to trigger its conduction; the control module is used to send a reset signal and a trigger signal to respectively control the operation of the reset circuit and the closure of the switch in the RSD pre-trigger circuit, thereby causing the RSD pre-trigger circuit and the reset circuit to operate; the discharge main circuit is used to generate a pulse current with an ultra-high amplitude and current rise rate in the circuit after the magnetic switch is saturated and the RSD is reversely charged, and this pulse current is fed into a single-turn coil to generate an ultra-strong magnetic field at the center of the single-turn coil;

[0034] Further preferably, the main discharge circuit includes a main capacitor, a magnetic switch, an RSD and a single-turn coil; wherein the discharge voltage of the main capacitor and the RSD pre-trigger capacitor are both 30kV, and the capacitance is both 10.4μF;

[0035] The anode of the main capacitor in the main discharge circuit is connected to the anode of the RSD through a copper bar; one end of the copper bar is connected to the anode of the main capacitor, and the other end is connected to the anode of the RSD through a magnetic switch; the cathode of the main capacitor is connected to one end of the single-turn coil through a copper bar, and the other end of the single-turn coil is connected to the cathode of the RSD through a copper bar;

[0036] The magnetic switch is a ring structure made of a special magnetic conductive material as the magnetic core, with epoxy pressed on the outer layer of the magnetic core. The single-turn coil is a specially made magnet with only one turn of wire. The two ends of the magnetic coil are welded to the outer surface of two parallel electrode plates.

[0037] Further preferably, the magnetic switch in the main circuit can be passed through by multiple copper bars, each copper bar being connected to a group of RSDs;

[0038] Further preferably, the connection between the RSD and the single-turn coil is connected by a copper bar, multiple groups of RSD correspond to multiple copper bars, and each end of the single-turn coil is connected to only one copper bar, and the multiple copper bars are connected to a copper bar at one end of the single-turn coil through an adapter;

[0039] Further preferably, in order to withstand high current peak, high withstand voltage and high current rise rate, the RSD device can be composed of a plurality of RSDs connected in series and parallel according to actual conditions;

[0040] like Figure 2 As shown, the RSD pre-trigger circuit includes an RSD pre-trigger capacitor and an RSD pre-trigger circuit switch; the anode of the RSD pre-trigger capacitor is connected to the cathode of the RSD via a copper bus; the cathode of the RSD pre-trigger capacitor is connected to the anode of the RSD via the RSD pre-trigger circuit switch; the RSD pre-trigger circuit switch controls the triggering of the RSD pre-trigger circuit and also controls the operation of the entire destructive strong magnetic field system;

[0041] Further preferably, the RSD pre-trigger circuit switch may be a gas switch, a ball gap switch, a thyristor or an IGBT;

[0042] Further preferably, the RSD pre-trigger circuit can realize synchronous triggering and opening of multiple groups of series-parallel RSDs;

[0043] Further preferably, the RSD pre-trigger circuit switch may be composed of a plurality of switches connected in series and in parallel.

[0044] The specific operation process of the strong magnetic field system provided by this application is as follows:

[0045] Before discharging, the control module first sends a reset signal to control the magnetic switch reset circuit to operate, and performs a reset operation on the magnetic switch, so that the magnetic material in the magnetic switch is at the negative saturation point of the magnetic hysteresis loop, at which time the relative magnetic permeability of the magnetic material is large, so that the inductance of the magnetic switch will be large in the short time after the trigger switch is closed, resulting in a large inductive reactance, and the magnetic switch is equivalent to an open circuit in the main circuit, which will isolate the RSD and the main capacitor voltage; After the magnetic switch is reset, the main capacitor charging power supply and the RSD pre-trigger capacitor charging power supply are started to charge the main capacitor and the RSD pre-trigger capacitor respectively; the control module sends a trigger signal to the gas switch, and after the trigger switch in the RSD pre-trigger circuit is closed, the RSD pre-trigger capacitor will charge the RSD in reverse; at this time, the RSD, the RSD pre-trigger capacitor, the RSD pre-trigger circuit stray inductance and the RSD pre-trigger circuit non-ideal impedance form a series RLC second-order circuit; the charging current waveform of the RSD pre-trigger capacitor to the RSD is a pulse current wave with a duration of 2-3μs; wherein the RSD can be equivalent to a diode;

[0046] The RSD characteristic is that it needs to be reverse charged to inject charge before conduction, which is the pre-trigger process of the RSD, and the greater the pre-charge charge, the higher the current rise rate that the RSD can withstand during discharging in the main circuit after conduction; wherein the pre-charge charge of the RSD pre-trigger capacitor to the RSD is the integral of the pre-charge current of the RSD pre-trigger capacitor to the RSD with respect to time, and the integral time is the duration of the pre-charge current;

[0047] After the gas switch is closed, the RSD pre-trigger capacitor charges the RSD in reverse, and the magnetic switch in the main circuit plays a role in isolating the RSD and the main capacitor for a short time, and the isolation time is basically equal to the pre-charge time of the RSD pre-trigger circuit; during this isolation time, the voltage of the main capacitor does not affect the RSD pre-charge circuit, ensuring that the reverse charging process of the RSD pre-trigger capacitor to the RSD is not affected, thereby normally triggering the RSD;

[0048] Further, during the RSD pre-trigger period, the magnetic switch gradually moves from the negative saturation point to the positive saturation point of the magnetic hysteresis loop due to the positive voltage of the main capacitor, and the inductance of the magnetic switch also changes from large to small, and after the positive saturation, the magnetic switch can be approximated as a short circuit, i.e. the magnetic switch is turned on; it takes about 2μs for the magnetic switch to work from the negative saturation point to the positive saturation point, which plays a role in isolating the main capacitor and the RSD, avoiding the influence of the main capacitor voltage on the pre-trigger process of the RSD;

[0049] The magnetic switch is turned on after saturation, and the inductance can be ignored. At this time, the RSD pre-triggering process has also been completed. After the RSD is successfully triggered, the main capacitor discharges to the single-turn coil through the magnetic switch, the RSD, and the line impedance of the main discharge circuit. The single-turn coil flows through a pulse current with a super-high amplitude and a current rise rate, and generates a super-strong magnetic field at the center of the single-turn coil. In the single-turn coil, each device is connected by a copper bar, and the main circuit discharge circuit can be equivalent to a second-order RLC series circuit.

[0050] Figure 3 The single-turn coil magnet provided by the embodiment of the application is shown in the schematic diagram. The coil of the magnet is only one turn of wire, and the outer surfaces of the two electrode plates are respectively welded to the two ends of the coil of the magnet. The electrode plates are two parallel copper plates connected with the copper bar in the main circuit. After the main capacitor discharges, the pulse current is fed into the single-turn coil through the electrode plates, and a super-strong magnetic field is generated at the center of the single-turn coil magnet.

[0051] Figure 4 The current simulation schematic diagram of the main circuit discharge process of the embodiment of the application is shown. The peak current is more than 300 kA, and the current rise rate is more than 200 kA / μs. The single RSD can withstand a voltage of 3 kV and a current rise rate of 100 kA / μs. The single RSD can pass a pulse current with a peak value of 80-100 kA. In the embodiment, 4-5 groups of RSDs are connected in parallel to share the current, and each group of RSDs is connected in series by 10-15 pieces.

[0052] Figure 5 The magnetic field simulation schematic diagram of the center of the single-turn coil in the main circuit discharge process of the embodiment of the application is shown. The magnetic induction intensity reaches a peak value of 78T at 1.3μs.

[0053] Compared with the prior art, the application has the following advantages:

[0054] The strong magnetic field system provided by the application introduces a semiconductor RSD into a destructive strong magnetic field system. The RSD is a new type of high-power pulse semiconductor, which has high voltage resistance, strong current passing capacity, and high current rise rate. Therefore, the single-turn coil type destructive strong magnetic field system of the application can better achieve the goal of passing a current with a higher amplitude and a higher rise rate in the main discharge circuit, and thus can generate a stronger magnetic field in the single-turn coil. Compared with the destructive pulse strong magnetic field system using multiple gas switches in parallel, the structure of the application is simplified, the high-amplitude magnetic field can be generated in the single-turn coil for multiple times, and the cost is reduced. The system occupies a smaller space volume.

[0055] It should be understood that the terms such as "include" and "may include" used in the present application indicate the presence of the disclosed functions, operations, or components, and do not limit one or more additional functions, operations, and components. In the present application, terms such as "include" and / or "have" can be interpreted to mean that a specific characteristic, number, operation, component, element, or combination thereof is present, but can not be interpreted to exclude the presence or addition of one or more other characteristics, numbers, operations, components, elements, or combinations thereof.

[0056] In addition, in the present application, the expression "and / or" includes any and all combinations of the listed terms. For example, the expression "A and / or B" can include A, can include B, or can include both A and B.

[0057] In the description of the embodiments of the present application, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, "connection" can be detachable connection, or can be non-detachable connection; can be direct connection, or can be indirect connection through intermediate medium. Among them, "fixed connection" means that the relative positional relationship after connection is unchanged. "Rotational connection" means that the relative rotation after connection is connected. "Sliding connection" means that the relative sliding after connection is connected. The orientation language mentioned in the embodiments of the present application, such as "top", "bottom", "inner", "outer", "left", "right", etc., is only the direction of the drawing, therefore, the orientation language used is to better, more clearly illustrate and understand the embodiments of the present application, and is not to indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the embodiments of the present application.

[0058] In addition, in the embodiments of the present application, the mathematical concepts mentioned, symmetry, equality, parallel, perpendicular, etc. These limitations are all for the current process level, and are not strictly defined in the mathematical sense, and a small amount of deviation is allowed, approximately symmetrical, approximately equal, approximately parallel, approximately perpendicular, etc. For example, A is parallel to B, which means that A and B are parallel or approximately parallel, the included angle between A and B can be between 0 degrees and 10 degrees. A and B are perpendicular, which means that A and B are perpendicular or approximately perpendicular, the included angle between A and B can be between 80 degrees and 100 degrees.

[0059] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed in the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A strong magnetic field system, characterized in that: It includes a discharge main circuit, an RSD pre-trigger circuit, a magnetic switch reset circuit and a control module; The output end of the control module is connected to the magnetic switch reset circuit and the RSD pre-trigger circuit; the demagnetization coil in the magnetic switch reset circuit is wound around the magnetic switch; the RSD pre-trigger circuit is connected to both ends of the RSD of the discharge main circuit; The main discharge circuit includes a main capacitor, a magnetic switch, an RSD and a single-turn coil; the anode of the RSD is connected to the anode of the main capacitor through the magnetic switch; the cathode of the RSD is connected to the cathode of the main capacitor through the single-turn coil; The control module is used to provide a reset signal for the magnetic switch reset circuit and a trigger signal for the RSD pre-trigger circuit; the reset signal is used to control the current to flow through the demagnetization coil in the magnetic switch reset circuit, generating a demagnetization magnetic field in the magnetic switch core for reset; the RSD pre-trigger circuit is used to reverse charge the RSD and trigger its conduction after receiving the trigger signal; The main discharge circuit is used to feed a pulse current with an amplitude and a current rise rate higher than a preset threshold to the single-turn coil after the magnetic switch is saturated and the RSD is reversely charged, thereby generating a strong magnetic field in the single-turn coil.

2. The high magnetic field system according to claim 1, characterized in that: In order to withstand the high-amplitude pulse current of the main discharge circuit, the anode of the RSD is connected to the anode of the main capacitor through a copper bar passing through the magnetic switch; the cathode of the main capacitor is connected to one end of the single-turn coil through a copper bar, and the other end of the single-turn coil is connected to the cathode of the RSD through a copper bar.

3. The high magnetic field system according to claim 1 or 2, characterized in that: The magnetic switch is a ring structure composed of a magnetic core and epoxy pressed on the outer layer of the magnetic core, and the main capacitor current copper bar passes through the magnetic switch.

4. The high magnetic field system according to claim 1, characterized in that: The single-turn coil includes a magnetic coil and two electrode plates; the magnetic coil is a turn of wire, and both ends of the magnetic coil are welded to the outer surfaces of the two electrode plates, and the two electrode plates are two parallel metal plates.

5. The high magnetic field system according to claim 2, characterized in that: According to the actual required current peak, voltage resistance and high current rise rate, multiple RSDs are set up in series and parallel, and multiple groups of RSDs correspond to multiple copper bars. The two ends of the single-turn coil are each connected to a copper bar, and the multiple copper bars are connected to a copper bar at one end of the single-turn coil through an adapter.

6. A method for obtaining a strong magnetic field based on the strong magnetic field system according to any one of claims 1 to 5, characterized in that: The specific steps include: Based on the reset signal, the magnetic switch is reset to make the magnetic material in the magnetic switch at the negative saturation point of the hysteresis loop. The magnetic switch is equivalent to an open circuit, isolating the RSD from the main capacitor voltage. The main capacitor is charged by a main capacitor charging power supply, and the RSD pre-trigger capacitor is charged by an RSD pre-trigger capacitor charging power supply; When the main capacitor and the RSD pre-trigger capacitor are charged, based on the trigger signal, the RSD pre-trigger circuit switch is controlled to close, so that the RSD pre-trigger capacitor reversely charges the RSD; When the amount of charge reversely charged into the RSD by the RSD pre-trigger capacitor during the RSD pre-trigger process makes the RSD forward conduction degree meet the actual needs, and at the same time, after the magnetic switch is saturated and turned on, the main capacitor discharges to the single-turn coil through the magnetic switch and RSD, and the single-turn coil is fed with a pulse current with an amplitude and current rise rate higher than the preset threshold, generating a strong magnetic field at the center of the single-turn coil.

7. The method for obtaining a strong magnetic field of a strong magnetic field system according to claim 6, characterized in that: In the RSD pre-trigger stage, the main capacitor applies a positive voltage to the magnetic switch, and the magnetic switch moves from the negative saturation point of the hysteresis loop to the positive saturation point of the hysteresis loop. The inductance of the magnetic switch changes from large to small. After positive saturation, the magnetic switch is equivalent to a short circuit, the magnetic switch is turned on, the main capacitor is discharged, and a strong magnetic field is generated in the center of the single-turn coil.

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