Reverse switch transistor pulse generation circuit without magnetic switch

Abstract

The invention belongs to the technical field of pulse power, and particularly discloses a reverse switching transistor pulse generation circuit without a magnetic switch. According to the invention, the pulse capacitor is used as a pre-charging power supply and a main power supply to carry out reverse pre-charging and forward main discharging on the reverse switching transistor. The isolation inductor can realize automatic isolation, and the pre-charging current completes reverse charging when the main current does not go up. On one hand, a magnetic switch is omitted, the problem that the volume, the weight and the cost of the magnetic switch are increased due to the fact that the volt-second product of the magnetic switch is increased along with the voltage of the main capacitor is solved, and the reverse switch can be applied to the field of ultrahigh-voltage pulse power of 10 kV or above in a relatively easy and relatively low-cost mode. And on the other hand, the circuits in the application are all composed of common circuit elements, special devices which are difficult to obtain are not included, and the circuits have relatively simple structures and are easy to assemble and construct.

Description

Technical Field

[0001] The present application belongs to the field of pulse power technology, and more specifically, relates to a reverse switching transistor pulse generating circuit that does not require a magnetic switch. Background Art

[0002] The reverse switching transistor (RSD) is a new type of special power semiconductor device with extremely high current rise rate, extremely high current capacity, low stray inductance, and simple flat-panel packaging structure. Theoretically, a single RSD can withstand a current rise rate of up to 10 11 A / s, and the current carrying capacity is as high as several hundred kiloamperes. In addition, RSD is a two-terminal device without a gate. It is triggered by reverse precharging, and can be fully and evenly opened when triggered. Theoretically, it can be connected in series infinitely. The stack composed of multiple RSD monolithic chips pressed in series can be triggered together with reverse current, and there is almost no problem of equalizing the voltage. Therefore, RSD is particularly suitable for high-voltage and high-current pulse power fields that traditional power electronic devices, including thyristors, are difficult to handle.

[0003] A magnetic switch is required in the traditional RSD circuit to isolate the main capacitor voltage. Before triggering, a DC current is used to reset the magnetic switch to the reverse saturation point. When triggered, the precharge capacitor first discharges the RSD in the reverse direction. During this period, the voltage of the main capacitor is isolated by the magnetic switch, which has not yet been saturated. At the end of the precharge process, which lasts for about 2 microseconds, the magnetic switch is just saturated and the main capacitor begins to discharge forward to the RSD. The product of the main capacitor voltage isolated by the magnetic switch and the isolation time is the volt-second product of the magnetic switch.

[0004] Although RSD can be connected in series infinitely in theory to withstand very high main capacitor voltage, the existence of magnetic switches becomes a bottleneck problem for further voltage increase. The volume, weight, and cost of magnetic switches will increase with the increase of volt-second product. For example, when the volt-second product of the magnetic switch is as high as 40mVs (corresponding to blocking 20kV voltage for 2 microseconds), the weight of the magnetic switch has reached hundreds of kilograms and the diameter is nearly one meter. Therefore, the discharge circuit of the traditional RSD is actually difficult to apply in the pulse power circuit of tens of kilovolts.

[0005] In response to this problem, patent CN110138360A proposes a demagnetization switch high-efficiency pulse power generation circuit based on RSD, including: a reverse switch transistor RSD, a reverse blocking two-terminal solid-state thyristor RBDT and a peripheral circuit; when the reverse switch transistor RSD needs to be triggered, the alternation of capacitor energy storage and inductor energy storage in the peripheral circuit is used to make the reverse switch transistor RSD normally triggered and turned on without a magnetic switch; the reverse blocking two-terminal solid-state thyristor RBDT is used to transfer part of the energy in the capacitor to the inductor energy storage branch to prevent the reverse current from being too large when the RSD is triggered. It assists the RSD by using another semiconductor switching device RBDT to prevent the current flowing through the RSD from being too large and damaging the RSD when it is triggered. Since the RBDT is very small, the volume can be significantly reduced. In order to reduce the energy loss of the pulse power generation circuit, when the RSD is triggered, the inductor is used to store the energy released by the capacitor when the RSD is triggered, and finally, the inductor releases the stored energy to form a load current pulse.

[0006] However, the circuit itself is complex, the control is complex, and the reverse blocking two-terminal solid-state thyristor (RBDT) device is a special device and is difficult to obtain. Summary of the invention

[0007] In view of the defects of the prior art, the purpose of the present application is to provide a reverse switching transistor pulse generating circuit that does not require a magnetic switch, aiming to solve the problem that the existing RSD discharge circuit is difficult to apply in a pulse power circuit with a voltage of tens of kilovolts.

[0008] The present application relates to a reverse switching transistor pulse generating circuit that does not require a magnetic switch, the pulse generating circuit comprising a main circuit and a trigger circuit; the main circuit is composed of a main capacitor, a blocking inductor and an RSD, the positive electrode of the main capacitor is connected to one end of the blocking inductor, the negative electrode is connected to the RSD cathode, and the other end of the blocking inductor is connected to the RSD anode; the time constant of the main circuit is greater than the time constant of the trigger circuit, so that the discharge speed of the main circuit is slower than the discharge speed of the trigger circuit; during the triggering of the RSD, the main capacitor voltage is isolated by the blocking inductor in the main circuit.

[0009] Preferably, the blocking inductor is a linear inductor with an inductance value of at least microhenry and a withstand voltage of tens of kilovolts.

[0010] Preferably, the trigger circuit includes: a switch, an isolation diode and a pre-charge capacitor; one end of the switch is connected to the RSD anode, and the other end is connected to the positive electrode of the isolation diode, which is used to control the discharge of the trigger circuit when closed; the negative electrode of the pre-charge capacitor is connected to the negative electrode of the isolation diode, and the positive electrode is connected to the cathode of the RSD.

[0011] Preferably, the reverse recovery time of the isolation diode is in nanosecond order.

[0012] Preferably, the reverse withstand voltage capability of the isolation diode is the sum of the voltages of the pre-charge capacitor and the main capacitor, and the current carrying capacity is greater than the discharge peak current of the pre-charge capacitor.

[0013] Preferably, the isolation diode is a single Schottky diode or a plurality of Schottky diodes connected in series and parallel.

[0014] Preferably, the trigger circuit further comprises: an anti-reverse diode, the anode of which is connected to the anode of the isolation diode, and the cathode of which is connected to the anode of the RSD.

[0015] Preferably, the main capacitor and the pre-charge capacitor are both pulse capacitors.

[0016] Preferably, the pulse capacitor has a withstand voltage of several kilovolts to several tens of kilovolts, a capacity of microfarads, and a current carrying capacity of several kiloamperes to several tens of kiloamperes.

[0017] Preferably, the ability of the main capacitor to withstand reverse peak current is not less than the forward peak value of the main discharge current.

[0018] In general, the above technical solutions conceived by this application have the following beneficial effects compared with the prior art:

[0019] The present application proposes a reverse switch transistor pulse generating circuit that does not require a magnetic switch. The pulse capacitor serves as a pre-charge source and a main power source to perform reverse pre-charge and forward main discharge on the reverse switch transistor, respectively. The isolation inductor can realize automatic isolation, and the pre-charge current has completed reverse charging before the main current rises. On the one hand, the present application omits the magnetic switch, and solves the problem of increased volume, weight, and cost of the magnetic switch caused by the increase of the volt-second product of the magnetic switch with the increase of the main capacitor voltage, so that the reverse switch can be applied to the field of ultra-high voltage pulse power above 10kV in a relatively easy and low-cost manner. On the other hand, the circuits in the present application are all composed of common circuit elements, do not include special devices that are difficult to obtain, and the circuit has a relatively simple structure and is easy to assemble and build. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a reverse switching transistor pulse generating circuit that does not require a magnetic switch, provided in an embodiment of the present application.

[0021] Figure 2 Schematic diagram of the discharge sequence of the pulse generating circuit provided in an embodiment of the present application, wherein (a) corresponds to the charging of two capacitors, (b) corresponds to the reverse discharge of the pre-charged capacitor to RSD, and (c) corresponds to the end of the reverse discharge.

[0022] Figure 3 Schematic diagram of RSD current provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0024] The embodiments of the present application are described below in conjunction with the drawings in the embodiments of the present application.

[0025] like Figure 1 As shown, the present application discloses a reverse switching transistor pulse generating circuit that does not require a magnetic switch, the pulse generating circuit comprising a main circuit and a trigger circuit; the main circuit is composed of a main capacitor C1, a blocking inductor L1 and an RSD, the positive electrode of the main capacitor C1 is connected to one end of the blocking inductor L1, the negative electrode is connected to the RSD cathode, and the other end of the blocking inductor L1 is connected to the RSD anode; the time constant of the main circuit is greater than the time constant of the trigger circuit, so that the discharge speed of the main circuit is slower than the discharge speed of the trigger circuit; during the triggering of the RSD, the voltage of the main capacitor C1 is isolated by the blocking inductor in the main circuit.

[0026] Preferably, the blocking inductor is a linear inductor with an inductance value of at least microhenry and a withstand voltage of tens of kilovolts.

[0027] It should be noted that the isolation inductor has a large inductance value to ensure that the main capacitor discharge current does not increase to a level equivalent to the pre-charge current before the pre-charge discharge is completed. The isolation inductor should not use magnetic materials as the magnetic core, otherwise it may quickly saturate during discharge, resulting in isolation failure, and then causing RSD trigger failure. In an embodiment shown, the isolation inductor is composed of a hollow solenoid.

[0028] Furthermore, polyimide insulation may be used between turns of the isolation inductor to avoid turn-to-turn breakdown.

[0029] Preferably, the trigger circuit includes: a switch S3, an isolation diode D2 and a pre-charge capacitor C2; one end of the switch S3 is connected to the anode of RSD, and the other end is connected to the positive electrode of the isolation diode D2, which is used to control the discharge of the trigger circuit when closed; the negative electrode of the pre-charge capacitor C2 is connected to the negative electrode of the isolation diode D2, and the positive electrode is connected to the cathode of RSD.

[0030] Preferably, the reverse recovery time of the isolation diode D2 is in nanosecond order.

[0031] Preferably, the reverse withstand voltage capability of the isolation diode D2 is the sum of the voltages of the pre-charge capacitor and the main capacitor, and the current carrying capacity is greater than the discharge peak current of the pre-charge capacitor.

[0032] Preferably, the isolation diode D2 is a single Schottky diode or a plurality of Schottky diodes connected in series and parallel.

[0033] It should be noted that in high voltage (voltage greater than 1kV) and high current (current greater than 1kA) situations, multiple Schottky diodes can be connected in series and parallel to meet the voltage resistance and current carrying requirements.

[0034] Preferably, the trigger circuit further comprises: an anti-reverse diode D1, whose anode is connected to the anode of the isolation diode D2, and whose cathode is connected to the anode of the RSD.

[0035] Preferably, the main capacitor and the pre-charge capacitor are both pulse capacitors.

[0036] Furthermore, both the main capacitor and the pre-charge capacitor should have a small self-inductance, not exceeding several tens of nH.

[0037] Preferably, the pulse capacitor has a withstand voltage of several kilovolts to several tens of kilovolts, a capacity of microfarads, and a current carrying capacity of several kiloamperes to several tens of kiloamperes.

[0038] Preferably, the ability of the main capacitor to withstand reverse peak current is not less than the forward peak value of the main discharge current.

[0039] It should be noted that the present application prefers the above design to satisfy the requirement that the main discharge circuit is a second-order RLC underdamped circuit.

[0040] The present application proposes a reverse switching transistor pulse generating circuit that does not require a magnetic switch, which can be applied to fault current collectors FCL in power grids, single-turn coil systems of destructive strong magnetic field devices, high-power pulse generating devices, etc.

[0041] Example

[0042] In this embodiment, the main capacitor C1 is 7.5 microfarads, the charging voltage is 1800V, the pre-charge capacitor C2 is 2.5 microfarads, and the charging voltage is 1200V. The isolation inductor is 5.2 microhenries. The diameter of the RSD is 35mm. The switches S1 and S2 of the isolation capacitor and the charging voltage source (U1 and U2) use high-voltage vacuum relays, and the switch S3 that controls the discharge of the pre-charge circuit is an IGBT.

[0043] The complete working process of the pulse generating circuit is as follows:

[0044] First, close S1 and S2 to charge C1 and C2. The circuit is as follows Figure 2 As shown in (a);

[0045] Secondly, close S3, and the pre-charge capacitor C2 discharges RSD in the reverse direction. The circuit is as follows Figure 2 As shown in (b), at this time, the main capacitor C1 is kept at a low level due to the limitation of inductor L1;

[0046] Then, the circuit is as Figure 2As shown in (c), the reverse discharge of RSD ends, that is, RSD is forward-conducting. At this time, the main circuit officially starts to discharge, the main current has risen to a higher level, and the forward current begins to flow through RSD. After the pre-charge current drops to 0, the diode D2 is cut off, and the main current completely flows through RSD, realizing RSD triggering.

[0047] From the above analysis, we can know that after the IGBT is turned on, due to the blocking effect of the isolation inductor, the main circuit current rises slowly, while the pre-charge circuit current rises quickly, so the reverse pre-charge current flows through RSD. Then, the diode D1 cuts off the reverse current of the pre-charge circuit. At this time, the main capacitor current is already large, so the forward current flows through RSD.

[0048] like Figure 3 As shown in the figure, the RSD first flows through the reverse precharge current, and then the forward conduction flows through the main current. The peak value of the main current is as high as 2000A.

[0049] It should be understood that expressions such as "including" and "may include" that may be used in the present application indicate the existence of the disclosed functions, operations, or constituent elements, and do not limit one or more additional functions, operations, and constituent elements. In the present application, terms such as "including" and / or "having" may be interpreted as indicating specific characteristics, numbers, operations, constituent elements, components, or combinations thereof, but may not be interpreted as excluding the existence or possibility of adding one or more other characteristics, numbers, operations, constituent elements, components, or combinations thereof.

[0050] The term "and / or" in this application is a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. The symbol " / " in this application indicates that the associated objects are in an or relationship, for example, A / B means A or B.

[0051] The terms "first" and "second" in the specification and claims of this application are used to distinguish different objects rather than to describe a specific order of objects. For example, a first response message and a second response message are used to distinguish different response messages rather than to describe a specific order of response messages.

[0052] In the embodiments of the present 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 the present application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0053] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc.; multiple elements refer to two or more elements, etc.

[0054] 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 who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A reverse switching transistor pulse generating circuit that does not require a magnetic switch, characterized in that: Including main circuit and trigger circuit; The main circuit is composed of a main capacitor, a blocking inductor and an RSD, wherein the positive electrode of the main capacitor is connected to one end of the blocking inductor, the negative electrode is connected to the cathode of the RSD, and the other end of the blocking inductor is connected to the anode of the RSD; The time constant of the main circuit is greater than the time constant of the trigger circuit, so that the discharge speed of the main circuit is slower than the discharge speed of the trigger circuit; During the triggering of RSD, the main capacitor voltage is isolated by the blocking inductor in the main circuit.

2. The pulse generating circuit according to claim 1, characterized in that: The blocking inductor is a linear inductor with an inductance value of at least microhenry and a withstand voltage of tens of kilovolts.

3. The pulse generating circuit according to claim 1, characterized in that: The trigger circuit comprises: a switch, an isolation diode and a pre-charge capacitor; One end of the switch is connected to the anode of RSD, and the other end is connected to the anode of the isolation diode, which is used to control the discharge of the trigger circuit when closed; The negative electrode of the precharge capacitor is connected to the negative electrode of the isolation diode, and the positive electrode is connected to the cathode of RSD.

4. The pulse generating circuit according to claim 3, characterized in that: The reverse recovery time of the isolation diode is in nanosecond order.

5. The pulse generating circuit according to claim 3, characterized in that: The reverse withstand voltage capability of the isolation diode is the sum of the voltages of the pre-charge capacitor and the main capacitor, and the current carrying capacity is greater than the discharge peak current of the pre-charge capacitor.

6. The pulse generating circuit according to claim 3, characterized in that: The isolation diode is a single Schottky diode or a plurality of Schottky diodes connected in series and parallel.

7. The pulse generating circuit according to any one of claims 3 to 6, characterized in that: The trigger circuit also includes: an anti-reverse diode, the positive electrode of which is connected to the positive electrode of the isolation diode, and the negative electrode of which is connected to the anode of the RSD.

8. The pulse generating circuit according to claim 1, characterized in that: The main capacitor and the pre-charge capacitor are both pulse capacitors.

9. The pulse generating circuit according to claim 8, characterized in that: The pulse capacitor has a withstand voltage of several thousand volts to several tens of kilovolts, a capacity of microfarads, and a current carrying capacity of several thousand amperes to several tens of kiloamperes.

10. The pulse generating circuit according to claim 1, characterized in that: The ability of the main capacitor to withstand reverse peak current is not less than the forward peak value of the main discharge current.

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