Pulse power unit and pulse power supply

Abstract

The application provides a pulse power unit and a pulse power supply, wherein the pulse power unit comprises a DC bus capacitor, a power electronic switching device, a freewheeling circuit, and a first busbar, a second busbar and a first output copper bar, the DC bus capacitor is mounted on the first busbar and the second busbar, and two ends of the DC bus capacitor are connected with the first busbar and the second busbar respectively, the first busbar is connected with a first end of the power electronic switching device, and a second end of the power electronic switching device is connected with the first output copper bar; the first output copper bar and the second busbar are connected with a load through conductors respectively; the freewheeling circuit is connected between the second busbar and the first output copper bar, and the equivalent connection line length between the freewheeling circuit and the second end of the power electronic switching device is smaller than the equivalent connection line length between the power electronic switching device and the load. The freewheeling circuit is arranged close to the power electronic switching device, so that the line length between the power electronic switching device and the freewheeling circuit is greatly reduced, and the parasitic inductance generated by the part of the line is greatly reduced.

Description

Technical Field

[0001] This application relates to the field of controlled nuclear fusion technology, specifically to a pulsed power unit and a pulsed power supply. Background Technology

[0002] Pulsed power supplies often use power electronic switching devices as the main switch to supply power to the load. When these power electronic switching devices are turned off, the parasitic inductance of the turn-off circuit must be considered. This parasitic inductance generates a large turn-off spike voltage across the power electronic switching device, which may damage it. Therefore, existing technologies (such as photovoltaic inverters and UPS systems) aim to minimize the parasitic inductance of the power electronic switching device's turn-off circuit to ensure its safe and reliable operation.

[0003] Similarly, in the pulsed power supply of the magnet coil in a controlled nuclear fusion device, a large voltage spike is generated between the load and the power electronic switching device when the power electronic switching device is turned off due to the large parasitic inductance. In some cases, this can lead to damage to the power electronic switching device. Therefore, in order to protect the pulsed power supply of the magnet coil, the existing methods of reducing the parasitic inductance of the power electronic switching device's turn-off circuit cannot solve the problem of excessively high turn-off voltage spikes. Even if the parasitic inductance of the power electronic switching device's turn-off circuit is made very small, the phenomenon of excessively high turn-off voltage spikes and damage to the power electronic switching device can still occur.

[0004] Therefore, improving the safety of power electronic switching devices in the pulse power supply of the magnet coil in a controlled nuclear fusion device has become an urgent technical problem to be solved. Summary of the Invention

[0005] This application provides a pulse power unit and a pulse power supply, which at least solves the technical problem of how to improve the safety of power electronic switching devices in the pulse power supply of the magnet coil in a controlled nuclear fusion device.

[0006] According to a first aspect, embodiments of this application provide a pulse power unit, comprising: a pulse rate unit including a DC bus capacitor, a power electronic switching device, and a freewheeling circuit; the power unit further comprising: a first busbar, a second busbar, and a first output copper busbar; wherein the DC bus capacitor is mounted on the first busbar and the second busbar, and both ends of the DC bus capacitor are respectively connected to the first busbar and the second busbar; the first busbar is connected to a first end of the power electronic switching device, and the second end of the power electronic switching device is connected to the first output copper busbar; the first output copper busbar and the second busbar are respectively connected to a load through conductors; the freewheeling circuit is connected between the second busbar and the first output copper busbar, and the equivalent connection length between the freewheeling circuit and the second end of the power electronic switching device is less than the equivalent connection length between the power electronic switching device and the load.

[0007] In one embodiment, the first busbar and the second busbar are stacked.

[0008] In one embodiment, the power electronic switching device and the first output copper busbar are sequentially installed from the first end of the first busbar along a direction away from the first end of the first busbar, and the power electronic switching device is disposed on the side of the first busbar facing away from the second busbar; the freewheeling circuit is installed between the first output copper busbar and the second busbar, located on the side of the power electronic switching device facing the second busbar.

[0009] In one embodiment, the freewheeling circuit includes at least one freewheeling resistor and at least one freewheeling diode, wherein the freewheeling resistor is connected in series with the freewheeling diode, the freewheeling resistor is mounted on a resistor support copper busbar, and the freewheeling diode is mounted on a diode support copper busbar.

[0010] In one embodiment, the resistor support copper busbar and the diode support copper busbar are arranged perpendicular to the first busbar and the second busbar.

[0011] In one embodiment, a resistor support copper busbar and a diode support copper busbar are sequentially installed between the first output copper busbar and the second busbar, with one of the resistor support copper busbar and the diode support copper busbar connected to the first output copper busbar and the other connected to the second busbar.

[0012] In one embodiment, the resistor support copper busbar, the freewheeling resistor, the diode support copper busbar, and the freewheeling diode are stacked and pressed together by a pressing device.

[0013] In one embodiment, a first input copper busbar is also connected to the first busbar, and a second input copper busbar is also connected to the second busbar.

[0014] In one embodiment, a second output copper busbar is also connected to the second busbar, and the first output copper busbar and the second output copper busbar are connected to both ends of the load.

[0015] According to a second aspect, embodiments of this application provide a pulsed power supply, including a plurality of pulsed power units as described in any one of the first aspects above, connected in series and / or in parallel, wherein every two pulse units are arranged in a mirror image.

[0016] This application has at least the following beneficial effects:

[0017] In this application, the first busbar and the second busbar serve as DC busbars carrying DC bus capacitors. The first terminal of a power electronic switching device is connected to the first busbar, and the second terminal is connected to the first output copper busbar. A freewheeling circuit is connected between the second busbar and the first output copper busbar. The first output copper busbar is used to connect to the load. The equivalent connection length between the freewheeling circuit and the second terminal of the power electronic switching device is less than the equivalent connection length between the power electronic switching device and the load. That is, the freewheeling circuit is positioned close to the power electronic switching device. The distance between the freewheeling circuit and the second terminal of the power electronic switching device is equivalent to a short copper busbar or a small portion of the first output copper busbar between the freewheeling circuit and the second terminal of the power electronic switching device, greatly reducing the power busbar capacitance. The reduced line length between the sub-switching device and the freewheeling circuit significantly decreases the parasitic inductance generated in this section of the line. Furthermore, since the load is a magnetic coil with high inductance, the current in the line between the freewheeling circuit and the load remains constant or changes only slightly at the moment the power electronic switching device is turned off. The self-induced voltage generated by the parasitic inductance of the connecting line between the freewheeling circuit and the load is very small when the power electronic switching device is turned off. Therefore, by placing the freewheeling circuit close to the power electronic switching device and away from the load, the distance between the connecting line and the power electronic switching device is very short, resulting in very small or even zero parasitic inductance. Moreover, during the freewheeling process, the rate of current decrease in this line can be adjusted by the resistance value of the freewheeling resistor in the freewheeling circuit, thus allowing precise control of the current decrease rate during the load freewheeling process. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the circuit principle of an exemplary pulse power unit according to an embodiment of this application;

[0021] Figure 2 This is a schematic structural diagram of an exemplary pulse power unit according to an embodiment of this application;

[0022] Figure 3 This is a schematic diagram illustrating the current flow direction of an exemplary pulse power unit in an embodiment of this application when the power electronic switching device is turned off;

[0023] Figure 4 This is a side view of an exemplary pulse power unit according to an embodiment of this application;

[0024] Figure 5 This is a schematic diagram of pulse power units arranged in a mirror image in an exemplary pulse power supply according to an embodiment of this application. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, including a series of units, systems, products, or devices is not necessarily limited to those explicitly listed, but may include units, systems, products, or devices not explicitly listed.

[0027] Referring to the description in the background art, even after reducing the peak voltage of power electronic switching devices by using existing techniques to reduce the parasitic inductance of the power electronic switching device's turn-off circuit in the pulse power supply of the magnet coil, damage to the power electronic switching devices still occurs. To address this issue, the applicant's research revealed that existing methods for reducing parasitic inductance are often applied to power electronic devices such as uninterruptible power supplies (UPS) and photovoltaic inverters. While both the pulse power supply of the magnet coil and the aforementioned power electronic devices reduce the parasitic inductance of the power electronic switching device's turn-off circuit, they do not consider the parasitic inductance between the power electronic switching device and the load. This parasitic inductance between the power electronic switching device and the load has almost no effect on the aforementioned power electronic devices, but it has a significant impact on the pulse power supply of the magnet coil. Research has found that damage to the pulse power supply of the magnet coil is often caused by the parasitic inductance between the power electronic switching device and the load. The reason is:

[0028] In uninterruptible power supplies (UPS), photovoltaic inverters, and other equipment, the power electronic switching devices do not require a separate freewheeling circuit between the load and the load. Instead, they utilize the freewheeling diode built into the power electronic switching device as the freewheeling circuit. At the instant the power electronic switching device is turned off, the current in the freewheeling loop between the load and the freewheeling diode remains almost constant. Therefore, the self-induced voltage generated by the parasitic inductance between the load and the freewheeling diode (power electronic switching device) at the instant the power electronic switching device is turned off is negligible. However, in the field of controlled nuclear fusion, pulsed power supplies power the magnet coil. After discharging the magnet coil, the stored electrical energy needs to be released. In controlled nuclear fusion, the current drop rate of the magnet coil during energy release must be sufficiently large to generate a sufficient voltage across the magnet coil to break down the plasma. Therefore, if... Figure 1 As shown, an additional freewheeling circuit needs to be connected in parallel across the load to provide freewheeling current to the magnet coil, in order to maximize the rate of current descent in the magnet coil. At the instant the power electronic switching device turns off, the line between the load and the freewheeling circuit (i.e.,...) Figure 1 The current in line B) remains almost constant, and the self-induced voltage generated by the parasitic inductance in this line can be ignored. However, the line between the freewheeling circuit and the power electronic switching device (i.e., Figure 1 The current changes extremely rapidly in line A). Furthermore, due to the ease of installation of freewheeling circuits in existing technologies, they are often installed near the magnet coil. However, the physical distance between the pulse power supply and the magnet coil is considerable (potentially tens of meters), leading to a significant increase in the distance between the freewheeling circuit and the power electronic switching device (i.e.,...). Figure 1Line A) is relatively long. At the moment the power electronic switching device is turned off, the parasitic inductance on the line between the freewheeling circuit and the power electronic switching device is large, possibly reaching several or even tens of microhenries. This causes the power electronic switching device to generate a very large spike voltage pulse at the moment of turn-off, which may damage the power electronic switching device.

[0029] Based on this, this application provides a pulse power unit, such as... Figures 1 to 4 As shown, the pulse power unit 100 includes a DC bus capacitor 10, a power electronic switching device 20, and a freewheeling circuit 50, as well as a first busbar 31, a second busbar 32, and a first output copper busbar 41. The DC bus capacitor 10 is mounted on the first busbar 31 and the second busbar 32, and its two ends are respectively connected to the first busbar 31 and the second busbar 32. The first busbar 31 is connected to the first end 21 of the power electronic switching device 20, and the second end 22 of the power electronic switching device 20 is connected to the first output copper busbar 41. The first output copper busbar 41 and the second busbar 32 are respectively connected to the load through conductors. The freewheeling circuit 50 is connected between the second busbar 32 and the first output copper busbar 41. The equivalent connection length between the freewheeling circuit 50 and the first end 21 of the power electronic switching device 20 is less than the equivalent connection length between the freewheeling circuit 50 and the load.

[0030] In this application, the first busbar 31 and the second busbar 32 serve as DC busbars carrying the DC bus capacitor 10. The first terminal 21 of the power electronic switching device 20 is connected to the first busbar 31, and the second terminal 22 is connected to the first output copper busbar 41. A freewheeling circuit 50 is connected between the second busbar 32 and the first output copper busbar 41. The first output copper busbar 41 is used to connect to the load. The equivalent connection length between the freewheeling circuit 50 and the second terminal 22 of the power electronic switching device 20 is less than the equivalent connection length between the freewheeling circuit 50 and the load. That is, the freewheeling circuit 50 is positioned close to the power electronic switching device 20. The distance between them is equivalent to a short copper busbar or a very small portion of the first output copper busbar 41 between the freewheeling circuit 50 and the second terminal 22 of the power electronic switching device 20. This greatly reduces the line length between the power electronic switching device 20 and the freewheeling circuit 50, thereby greatly reducing the parasitic inductance generated by this part of the line. In addition, since the load is a magnetic coil with high inductance, the current in the line between the freewheeling circuit and the load remains unchanged or changes only slightly at the moment the power electronic switching device is turned off. The parasitic inductance of the connection line between the freewheeling circuit and the load generates a very small self-induced voltage when the power electronic switching device is turned off. Therefore, by setting the freewheeling circuit close to the power electronic switching device and away from the load, the distance between the connection line between the freewheeling circuit and the power electronic switching device is very short, and the parasitic inductance is very small. However, no matter how long the equivalent connection line length between the freewheeling circuit 50 and the load is, since the load is a magnetic coil with high inductance, the freewheeling circuit (e.g., ...) will generate a very small self-induced voltage at the moment the power electronic switching device 20 is turned off. Figure 1 The current on line B) shown remains constant or changes very little. Therefore, the spike voltage generated by the parasitic inductance on the freewheeling circuit 50 is very small. Furthermore, during the freewheeling process, the rate of current decrease on the freewheeling circuit 50 can be adjusted by the resistance value of the freewheeling resistor in the freewheeling circuit 50. Thus, the rate of current decrease during the load freewheeling process can be precisely controlled.

[0031] In one embodiment, the first busbar 31 and the second busbar 32 are stacked. The currents in the stacked first busbar 31 and the second busbar 32 are of the same magnitude but opposite in direction, thus canceling out the magnetic field generated by the currents and effectively reducing parasitic inductance. When the power electronic switching device 20 is turned off, the peak voltage between the DC bus capacitor 10 and the power electronic switching device 20 can be effectively reduced.

[0032] In one embodiment, a first busbar 31 and a second busbar 32 are stacked to form a stacked busbar, and a DC bus capacitor 10 is mounted on the stacked busbar. A power electronic switching device 20 and a first output copper busbar 41 are sequentially disposed at one end of the stacked busbar, with the power electronic switching device 20 mounted on the side of the first busbar 31 facing away from the second busbar 32. A mounting space for the freewheeling circuit 50 is provided between the first output copper busbar 41 and the second busbar 32, and the freewheeling circuit 50 is mounted within this space. The freewheeling circuit 50 is mounted on the side of the power electronic switching device 20 facing the second busbar 32.

[0033] The freewheeling circuit 50 and the power electronic switching device 20 are spatially opposite to each other. The line between the second terminal 22 of the power electronic switching device 20 and the freewheeling circuit 50 forms a relative layer with the cable on the freewheeling circuit 50. At the instant the power electronic switching device 20 is turned off, the line between the second terminal 22 of the power electronic switching device 20 and the freewheeling circuit 50 (… Figure 1 and Figure 3 The current on line A shown in the diagram ( Figure 3 Although the current Ia shown drops rapidly, it is still related to the current in the freewheeling circuit 50. Figure 3 The direction of the current Ib shown is opposite. The parasitic inductance generated by the current in the freewheeling circuit 50 is partially offset by the current in the line between the second terminal 22 of the power electronic switching device 20 and the freewheeling circuit 50, which can further reduce the parasitic inductance in this section of the line.

[0034] In one embodiment, the freewheeling circuit 50 includes at least one freewheeling resistor 51 and at least one freewheeling diode 52, wherein the freewheeling resistor 51 and the freewheeling diode 52 are connected in series, the freewheeling resistor 51 is mounted on a resistor support copper busbar 53, and the freewheeling diode 52 is mounted on a diode support copper busbar 54. The resistor support copper busbar 53 and the diode support copper busbar 54 are sequentially installed between the first output copper busbar 41 and the second busbar 32, with one of the resistor support copper busbar 53 and the diode support copper busbar 54 connected to the first output copper busbar 41 and the other connected to the second busbar 32.

[0035] In one embodiment, the resistor support copper busbar 53 and the diode support copper busbar 54 are arranged perpendicular to the stacked busbar 30. The resistor support copper busbar 53 and the diode support copper busbar 54 are often sheet-like structures. To reduce the length of the freewheeling circuit 50, the resistor support copper busbar 53 and the diode support copper busbar 54 are arranged perpendicular to the stacked busbar 30. The length of the freewheeling circuit 50 is then the sum of the lengths of the freewheeling resistor 51 and the freewheeling diode 52, as well as the thicknesses of the resistor support copper busbar 53 and the diode support copper busbar 54. This significantly shortens the length of the freewheeling circuit 50, resulting in very small voltage spikes during the freewheeling phase.

[0036] In one embodiment, the freewheeling resistor 51 can be pressed onto the resistor support copper busbar 53, and the freewheeling diode 52 can be pressed onto the diode support copper busbar 54. The resistor support copper busbar 53, the freewheeling resistor 51, the diode support copper busbar 54, and the freewheeling diode 52 are stacked and pressed together by a pressing device and fixedly connected between the stacked busbar 30 and the first output copper busbar 41.

[0037] In one embodiment, a first input copper busbar is further connected to the first busbar 31, and a second input copper busbar is further connected to the second busbar 32. A second output copper busbar 42 is also connected to the second busbar 32, and the first output copper busbar 41 and the second output copper busbar 42 are connected to both ends of the load.

[0038] This application embodiment also provides a pulsed power supply, including multiple pulsed power units 100 described in the above embodiments, wherein the multiple pulsed power units 100 are connected in series and / or in parallel to form a pulsed power supply according to the discharge requirements of the magnet coil. Since the parasitic inductance generated by the power electronic switching device 20 of the pulsed power unit 100 when it is turned off is small, and the peak voltage generated on the line between the power electronic switching device 20 and the freewheeling circuit 50 is small, the parasitic inductance and the turn-off voltage peak of the power electronic switching device 20 can still be reduced when the power output power is increased by increasing the number of series / parallel pulsed power units 100.

[0039] In one embodiment, such as Figure 5 As shown, the pulse power supply includes multiple pulse power units 100 connected in series and / or in parallel. In this embodiment, there is an even number of pulse power units 100, wherein every two pulse power units 100 are arranged in a mirror image. Multiple pairs of mirror-arranged pulse power units 100 constitute a pulse power supply, which can ensure the static and dynamic current sharing performance of each power electronic switching device 20 when multiple pulse power units 100 constitute a pulse power supply.

[0040] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0041] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A pulse power unit, characterized in that, include: DC bus capacitors, power electronic switching devices, freewheeling circuits, and first busbar, second busbar, and first output copper busbar, among which, The DC bus capacitor is installed on the first busbar and the second busbar, and the two ends of the DC bus capacitor are respectively connected to the first busbar and the second busbar. The first busbar is connected to the first end of the power electronic switching device, and the second end of the power electronic switching device is connected to the first output copper busbar. The first output copper busbar and the second busbar are respectively connected to the load through conductors; The freewheeling circuit is connected between the second busbar and the first output copper busbar. The equivalent connection length between the freewheeling circuit and the second terminal of the power electronic switching device is less than the equivalent connection length between the power electronic switching device and the load.

2. The pulse power unit as described in claim 1, characterized in that, The first busbar and the second busbar are stacked.

3. The pulse power unit as described in claim 2, characterized in that, Along a direction away from the first end of the first busbar, the power electronic switching device and the first output copper busbar are sequentially installed from the first end of the first busbar, and the power electronic switching device is installed on the side of the first busbar away from the second busbar; the freewheeling circuit is installed between the first output copper busbar and the second busbar, located on the side of the power electronic switching device facing the second busbar.

4. The pulse power unit as described in any one of claims 1 to 3, characterized in that, The freewheeling circuit includes at least one freewheeling resistor and at least one freewheeling diode, wherein the freewheeling resistor and the freewheeling diode are connected in series, the freewheeling resistor is mounted on a resistor support copper busbar, and the freewheeling diode is mounted on a diode support copper busbar.

5. The pulse power unit as described in claim 4, characterized in that, The resistor-supporting copper busbar and the diode-supporting copper busbar are arranged perpendicular to the first busbar and the second busbar.

6. The pulse power unit as described in claim 4, characterized in that, The resistor support copper busbar and the diode support copper busbar are installed sequentially between the first output copper busbar and the second busbar. One of the resistor support copper busbar and the diode support copper busbar is connected to the first output copper busbar, and the other is connected to the second busbar.

7. The pulse power unit as described in claim 6, characterized in that, The resistor support copper busbar, the freewheeling resistor, the diode support copper busbar, and the freewheeling diode are stacked and pressed together by a pressing device.

8. The pulse power unit as described in claim 1, characterized in that, A first input copper busbar is also connected to the first busbar, and a second input copper busbar is also connected to the second busbar.

9. The pulse power unit as described in claim 1, characterized in that, A second output copper busbar is also connected to the second busbar, and the first output copper busbar and the second output copper busbar are connected to both ends of the load.

10. A pulsed power supply, characterized in that, It includes multiple pulse power units as described in any one of claims 1 to 9, connected in series and / or in parallel.

Images