Pulse power supply

Abstract

Provided is a pulse power supply, comprising: a first switch branch configured to be turned on in a first stage, so that the pulse power supply provides a first discharge current to an inductive load; a second switch branch configured to be turned on in a second stage, so that the pulse power supply provides a second discharge current to the inductive load; a third switch branch configured to be turned on in a third stage, so that the pulse power supply provides a third discharge current to the inductive load; and a fourth switch branch configured to be turned on in a fourth stage, so that the pulse power supply provides a freewheeling path for the inductive load, wherein each switch branch is connected in parallel across the inductive load, and the second switch branch and the third switch branch share an energy storage capacitor. The pulse power supply can reduce the parasitic inductance and parasitic resistance in the link, thereby reducing the risk of oscillation of the power supply system and the loss of the power supply system, thereby improving efficiency, and can further simplify the power supply system and reduce system cost.

Description

Technical Field

[0001] This disclosure relates to the field of circuits, and more specifically, to a pulse power supply. Background Technology

[0002] In the field of controlled nuclear fusion, the field-reversed configuration (FRC) technology path has a simple system structure, low cost and operating cost. Compared with traditional tokamak devices, FRC fusion devices do not require a large number of external magnets to confine the plasma. The plasma autonomously forms an internal magnetic field, which significantly reduces manufacturing costs. At the same time, the high β value (close to 100%) of FRC plasma enables it to have higher fusion power output and facilitates direct energy recovery, thereby improving power generation efficiency.

[0003] The power system is crucial for the stable operation of the FRC fusion device. Its core lies in the θ-pinch coil and its associated high-voltage, high-power pulsed power supply. The θ-pinch coil is the key component responsible for "shaping" and "confining" the plasma. A high-voltage, high-power pulsed power supply is needed to excite the θ-pinch coil, sequentially discharging through four stages: bias, pre-ionization (PI), main, and crowbar. This allows the required current to flow through the θ-pinch coil at each stage, controlling the formation, ionization, ejection, and sustaining of the plasma. The precise discharge directly determines the plasma parameters.

[0004] High-voltage, high-power pulse power supplies are based on high-voltage pulse power technology: a high-voltage capacitor is pre-charged by a high-voltage power supply, and then the capacitor is discharged using a high-voltage, high-power switch, forming a pulse current waveform. The θ-pinch coil has extremely high requirements for the power supply's power rating and waveform control precision, and is also very expensive.

[0005] Therefore, how to reduce the cost of pulse power supplies and control the current waveform as precisely as possible is a key research focus in this field. Summary of the Invention

[0006] According to one aspect of this disclosure, a pulse power supply is provided, comprising: a first switching branch configured to be turned on in a first stage, such that the pulse power supply provides a first discharge current to an inductive load; a second switching branch configured to be turned on in a second stage, such that the pulse power supply provides a second discharge current to the inductive load; a third switching branch configured to be turned on in a third stage, such that the pulse power supply provides a third discharge current to the inductive load; and a fourth switching branch configured to be turned on in a fourth stage, such that the pulse power supply provides a freewheeling path for the inductive load, wherein the first, second, third, and fourth switching branches are connected in parallel across the inductive load, and the second and third switching branches share a common energy storage capacitor.

[0007] Optionally, the first switch branch includes a first switch, a first capacitor, and an inductor connected in series; the second switch branch includes a second switch, a second capacitor, and a third capacitor connected in series, wherein the third capacitor is a shared energy storage capacitor; the third switch branch includes a third switch and a third capacitor connected in series; and the fourth switch branch includes a fourth switch.

[0008] Optionally, the first capacitor has a matching first charging power supply and a first charging switch, and the third capacitor has a matching third charging power supply and a third charging switch.

[0009] Optionally, the second capacitor may not have a matching second charging power supply and a second charging switch, or it may have a matching second charging power supply and a second charging switch, wherein the absolute value of the power supply voltage of the first charging power supply and the third charging power supply is more than ten times the absolute value of the power supply voltage of the second charging power supply.

[0010] Optionally, during the pre-charging phase prior to the first stage, the first charging switch, the second charging switch, and the third charging switch are turned on to pre-charge the corresponding capacitors using their respective charging power supplies.

[0011] Optionally, in the second stage, the resonant current flowing through the second switch flows through the second and third capacitors connected in series, and in the third stage, the resonant current flowing through the second switch and the resonant current flowing through the third switch simultaneously flow through the third capacitor.

[0012] Optionally, the capacitance of the third capacitor is more than ten times that of the second capacitor.

[0013] Optionally, in the second stage, the equivalent capacitance formed by the second and third capacitors connected in series resonates with the parasitic inductance of the link, and in the third stage, the third capacitor also resonates with the parasitic inductance of the link.

[0014] Optionally, each of the first switch, the second switch, the third switch, and the fourth switch is a thyristor, a thyristor, a gas switch, or a semiconductor switch.

[0015] Optionally, the pulsed power supply is used for a field reaction-type (FRC) fusion device, the inductive load is a θ-pinch coil, and wherein the first to fourth stages correspond to the plasma bias stage, pre-ionization stage, main field stage, and follow current / crowbar stage, respectively.

[0016] Based on the aforementioned pulse power supply, by partially integrating the second and third switching branches (sharing a capacitor), parasitic inductance and resistance in the link are reduced, thus lowering the oscillation risk and power system losses, thereby improving efficiency. Furthermore, compared to traditional pulse power supplies, the charging voltage of the second capacitor is much lower than that of the first and third capacitors, therefore the voltage requirements for the power supply and switches in the charging circuit of the second capacitor are lower. In fact, the charging power supply and charging switch for the second capacitor can even be eliminated, further simplifying the power supply system and reducing system cost. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments of this disclosure or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments recorded in this disclosure. For those skilled in the art, other drawings can be obtained based on these accompanying drawings of the embodiments of this disclosure.

[0018] Figure 1A A schematic diagram of the structure of an FRC fusion device is shown, which feeds power to an inductive load (e.g., a load coil such as a θ-pinch coil).

[0019] Figure 1B An example circuit structure for an excitation power supply for an inductive load is shown.

[0020] Figure 2A It shows the basis Figure 1B The diagram shows the waveform of the current flowing through the θ-pinch coil in the first stage of the excitation power supply.

[0021] Figure 2B It shows the basis Figure 1B The waveform of the current flowing through the θ-pinch coil in the second stage of the excitation power supply is shown.

[0022] Figure 2C It shows the basis Figure 1B The waveform of the current flowing through the θ-pinch coil in the third stage of the excitation power supply is shown.

[0023] Figure 2D It shows the basis Figure 1BThe waveform of the current flowing through the θ-pinch coil in the fourth stage of the excitation power supply is shown.

[0024] Figure 3 A circuit diagram of a pulse power supply according to an embodiment of the present disclosure is shown.

[0025] Figure 4A It shows the basis Figure 3 The diagram shows the connection relationship of the pulse power supply 300 when the charging switch is closed during the pre-charging phase.

[0026] Figure 4B It shows the basis Figure 3 The diagram shows the connection relationship of the pulse power supply 300 when the charging switch is off during the pre-charging phase.

[0027] Figure 5A It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the first stage of the pulse power supply 300 is shown.

[0028] Figure 5B It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the second stage of the pulse power supply 300 is shown.

[0029] Figure 5C It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the third stage of the pulse power supply 300 is shown.

[0030] Figure 5D It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the fourth stage of the pulse power supply 300 is shown. Detailed Implementation

[0031] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0032] In most embodiments of this disclosure, the example of using a pulsed power supply to drive a θ-pinch coil in an FRC fusion device is illustrated. However, it should be understood that this is merely for illustrative purposes, and the pulsed power supply provided in the embodiments of this disclosure can be used to drive other types of inductive loads to provide the inductive load with a pulsed current having the desired pulse waveform.

[0033] Figure 1A A schematic diagram of the FRC fusion device is shown. Figure 1B An example circuit structure for an excitation power supply (i.e., a high-voltage, high-power pulsed power supply) for an θ-pinch coil is shown.

[0034] like Figure 1A As shown, the FRC fusion device 10 mainly includes a formation region 102 and a collision compression region 104. In the formation region 102, the θ-pinch coil LD is the most crucial component. It induces an angular current surrounding a plasma column within the coil LD by passing a rapidly changing large current through the cylindrical coil (θ direction). This angular current generates a radial magnetic field that rapidly compresses and heats the plasma. The performance of the excitation power supply 100 used to drive the θ-pinch coil LD directly determines the performance of the FRC fusion device.

[0035] like Figure 1B As shown, the two output terminals OUT+ and OUT- of the excitation power supply 100 for the θ-pinch coil LD are connected to the θ-pinch coil LD via a coaxial cable to form a current loop. The excitation power supply 100 includes four switching branches SWC1-SWC4. The first terminal of each switching branch is connected to the first terminal of the θ-pinch coil LD and the output terminal OUT+ of the excitation power supply 100, and the second terminal of each switching branch is connected to the second terminal of the θ-pinch coil LD and the output terminal OUT- of the excitation power supply 100.

[0036] Figure 1B Each switch branch shown corresponds to a discharge stage, which corresponds to a different state of plasma. They are turned on in sequence to generate a discharge current, which powers the θ-pinch coil that serves as the load.

[0037] As an example structure, in Figure 1B In the circuit, the first switch branch SWC1 includes an inductor L1, a first switch S1, and a first capacitor C1 connected in series. The first capacitor C1 is pre-charged by a first high-voltage DC power supply Vdc1, such that the initial voltage across its terminals is a first voltage value, for example, -24kV (e.g., ...). Figure 1B The first capacitor C1 is connected to the second terminal of the θ-pinch coil LD and the output terminal OUT of the excitation power supply 100, with the positive terminal being the first terminal. The second switch branch SWC2 includes a second switch S2 and a second capacitor C2 connected in series. The second capacitor C2 is pre-charged by the second high-voltage DC power supply Vdc2, and its initial voltage across its terminals is the second voltage value, for example, 40kV (e.g., ...). Figure 1BThe second capacitor C2 is connected to the second terminal of the θ-pinch coil LD and the output terminal OUT of the excitation power supply 100 (one terminal is the negative terminal). The third switch branch SWC3 includes the third switch S3 and the third capacitor C3 connected in series. The third capacitor C3 is pre-charged by the third high-voltage DC power supply Vdc3, and its initial voltage across its terminals is the third voltage value, for example, 40kV (e.g., ...). Figure 1B The third capacitor C3 is connected to the second terminal of the θ-pinch coil LD and the output terminal OUT of the excitation power supply 100 (the latter terminal is the negative terminal). The fourth switch branch SWC4 includes the fourth switch S4.

[0038] Figure 1B In this design, a first charging switch Br1 is positioned between the first high-voltage DC power supply Vdc1 and the first capacitor C1; a second charging switch Br2 is positioned between the second high-voltage DC power supply Vdc2 and the second capacitor C2; and a third charging switch Br3 is positioned between the third high-voltage DC power supply Vdc3 and the third capacitor C3. During the pre-charging phase, when these charging switches are turned on, the corresponding high-voltage power supplies are used to charge the corresponding capacitors. After charging is complete, each charging switch is turned off. In this way, the energy required to trigger a single fusion reaction can be stored in the first capacitor C1, the second capacitor C2, and the third capacitor C3 for subsequent discharge operations to output pulsed current.

[0039] In the context of this disclosure, each switch and charging switch may be a thyristor, a thyristor, a gas switch, or a semiconductor switch.

[0040] Figure 2A It shows the basis Figure 1B The diagram shows the waveform of the current flowing through the θ-pinch coil in the first stage of the excitation power supply. Figure 2B It shows the basis Figure 1B The waveform of the current flowing through the θ-pinch coil in the second stage of the excitation power supply is shown. Figure 2C It shows the basis Figure 1B The waveform of the current flowing through the θ-pinch coil in the third stage of the excitation power supply is shown. Figure 2D It shows the basis Figure 1B The waveform of the current flowing through the θ-pinch coil in the fourth stage of the excitation power supply is shown.

[0041] Figure 1B Each switch branch shown corresponds to a discharge stage, and is activated by turning on the corresponding switches S1-S4.

[0042] First, such as Figure 2AAs shown, the first stage (e.g., the bias stage) lasts for approximately tens of μs, generating a bias magnetic field that allows initial ionization of the plasma. During this stage, the first switch S1 is turned on, and the first capacitor C1 and the first inductor L1 resonate and discharge, with a peak current of approximately tens of kA and a resonant frequency of approximately several kHz. In this first stage, the direction of the discharge current flow is as follows... Figure 2A As shown, the negative direction is defined, meaning that the current flowing through the θ-pinch coil in this stage is negative and the absolute value gradually increases.

[0043] Then, as Figure 2B As shown, entering the second stage (e.g., the pre-ionization (PI) stage) generates a larger oscillation frequency, thus providing a better ionization environment for the initial plasma. In this stage, the first switch S1 is generally not actively turned off and therefore remains on, while the second switch S2 is on. The second capacitor C2 and the parasitic inductance on the link (not shown) resonate and discharge, with a peak-to-peak resonant current of tens of kA and a resonant frequency of tens of kHz or higher. In this second stage, the flow direction of the discharge current is as follows... Figure 2B As shown, it is still in the negative direction, that is, the current flowing through the θ-pinch coil LD in this stage is negative, and since the resonant frequency is larger than that in the first stage, the absolute value of the current can be seen to oscillate and change.

[0044] After that, as Figure 2C As shown, upon entering the third stage (e.g., the Main stage), the magnetic field rapidly reverses within a few μs as the current reverses, reconnecting the magnetic field lines and forming a closed magnetic field surface. This stage generates FRC plasma. The FRC plasma is then axially accelerated and ejected into the central chamber for collision and magnetic compression. During this stage, the first and second switches S1 and S2 are generally not actively turned off and remain on, while the third switch S3 is on. The third capacitor C3 and the parasitic inductance on the link (not shown) resonate and discharge at a frequency lower than in the second stage but higher than in the first stage. The current reverses rapidly, with peak-to-peak values ​​exceeding 100 kA, over a period of several μs. During this stage, the current flowing through the θ-pinch coil LD rapidly changes from negative to positive and then increases.

[0045] Finally, as Figure 2DAs shown, the process enters the fourth stage (e.g., the freewheeling / crowbar stage) to extend the duration of the FRC plasma. In this stage, the first switch S1, the second switch S2, and the third switch S3 are generally not actively turned off and remain on. The fourth switch S4 is on, thus short-circuiting the θ-pinch coil LD. The current in the θ-pinch coil LD gradually decreases from its positive peak, ensuring that for a period of time (e.g., hundreds of microseconds) during which the current begins to decrease from its peak value, the current is not less than a preset percentage of the peak value (e.g., 80% or other values), forming a pulsed current, and the discharge ends. The current flowing through the fourth switch in the fourth stage is essentially equivalent to the freewheeling current of the θ-pinch coil LD.

[0046] However, based on Figure 1B The following problem exists in the process of the excitation power supply shown exciting the inductive load (θ-pinch coil): 1. Four discharge branches are required, resulting in high parasitic inductance in the links and a high risk of power system oscillation. High parasitic resistance in the links leads to high power system losses and low efficiency.

[0047] 2. It requires three sets of high-voltage charging power supplies, which is costly and involves complex system insulation design.

[0048] Therefore, in order to solve the above problems, various embodiments of this disclosure provide a pulse power supply that can reduce parasitic inductance and parasitic resistance in the link, thereby reducing device cost and complexity, reducing oscillation of the output current waveform, and improving the efficiency of the power supply system.

[0049] Figure 3 A circuit diagram of a pulse power supply according to an embodiment of the present disclosure is shown.

[0050] like Figure 3 As shown, the pulse power supply 300 includes a first switching branch 310, a second switching branch 320, a third switching branch 330, and a fourth switching branch 340. The first switching branch 310, the second switching branch 320, the third switching branch 330, and the fourth switching branch 340 are connected in parallel to the two output terminals OUT+ and OUT- of the pulse power supply 300, thereby connecting to the two ends of the inductive load LD, for supplying power to the inductive load LD in different stages (e.g., the four stages of Bias, PI, Main, and Crowbar as described above).

[0051] For example, the first switching branch 310 is configured to turn on in a first stage (e.g., a bias stage), causing the pulse power supply 300 to provide a first discharge current to the inductive load LD. The second switching branch 320 is configured to turn on in a second stage (e.g., a PI stage), causing the pulse power supply 300 to provide a second discharge current to the inductive load. The third switching branch 330 is configured to turn on in a third stage (e.g., a main stage), causing the pulse power supply 300 to provide a third discharge current to the inductive load LD in the third stage. The fourth switching branch 340 is configured to turn on in a fourth stage (e.g., a crowbar stage), causing the pulse power supply 300 to provide a freewheeling path for the inductive load LD in the fourth stage. The second switching branch 320 and the third switching branch 330 share a capacitor.

[0052] In this embodiment, the circuit configuration and operation of the first switch branch 310 and the fourth switch branch 340 can be the same as described above. Figure 1B , Figure 2A and Figure 2B The first switch branch SWC1 and the fourth switch branch SWC4 are described as identical. For example, as follows: Figure 3 As shown, the first switch branch 310 may include a first switch S1, a first capacitor C1 and an inductor L1 connected in series, and the fourth switch branch 340 may include a fourth switch S4.

[0053] In addition, such as Figure 3 As further shown, the second switch branch 320 and the third switch branch 330 are coupled together through a third capacitor C3, meaning that the second switch branch 320 and the third switch branch 330 share the third capacitor C3. For example, the second switch branch 320 may include a second switch S2, a second capacitor C2, and a shared third capacitor C3 connected in series, and the third switch branch 330 may include a third switch S3 connected in series and a shared third capacitor C3. Figure 3 In this configuration, the negative terminal of the third capacitor C3 is connected to one output terminal OUT- of the pulse power supply, and the positive terminal of the third capacitor C3 is connected to one end of the second capacitor C2 and one end of the third switch S3. The other end of the second capacitor C2 is connected to the first terminal of the second switch S2, and the other ends of both the second switch S2 and the second switch S3 are connected to the other output terminal OUT+ of the pulse power supply. Of course, Figure 3 This is just an example; the connection order of the various circuit components can be changed. For example, the order of the second switch S2 and the second capacitor C2 can be swapped, or the third capacitor C3 can be connected to the other output terminal OUT+ of the pulse power supply, and so on.

[0054] Furthermore, since the first capacitor C1, the second capacitor C2, and the third capacitor C3 all need to be pre-charged to their respective voltage values, therefore Figure 3The diagram also shows charging power supplies (Vdc1, Vdc2, and Vdc3) and charging switches (Br1, Br2, and Br3) associated with each capacitor, used to charge each capacitor to its corresponding voltage value during the pre-charging phase and to disconnect the charging power supplies from the capacitors after charging is complete. However, it should be noted that although... Figure 3 The pulse power supply 300 includes various charging power supplies as an example for the market, but each charging power supply can be an external power supply independent of the pulse power supply, that is, not part of the pulse power supply 300.

[0055] Figure 4A It shows the basis Figure 3 The diagram shows the connection relationship of the pulse power supply 300 when the charging switch is closed during the pre-charging phase. Figure 4B It shows the basis Figure 3 The diagram shows the connection relationship of the pulse power supply 300 when the charging switch is off during the pre-charging phase.

[0056] like Figure 4A As shown, during the pre-charging phase, the first charging switch Br1, the second charging switch Br2, and the third charging switch Br3 are all turned on, allowing the high-voltage charging power supplies Vdc1, Vdc2, and Vdc3 to charge the corresponding capacitors C1, C2, and C3, respectively. After charging is complete, the charging switches Br1, Br2, and Br3 are turned off, as shown... Figure 4B As shown.

[0057] After the pre-charging phase ends, the pulse power supply 300 can sequentially provide discharge current to the inductive load LD or provide a freewheeling path for the inductive load LD in the first, second, third and fourth phases, so that the final pulse current flows through the inductive load LD.

[0058] Figure 5A It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the first stage of the pulse power supply 300 is shown. Figure 5B It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the second stage of the pulse power supply 300 is shown. Figure 5C It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the third stage of the pulse power supply 300 is shown. Figure 5D It shows the basis Figure 3 The waveform of the current flowing through the θ-pinch coil in the fourth stage of the pulse power supply 300 is shown.

[0059] Figure 5A Corresponding to the first stage, such as the Bias stage, its specific details are... Figure 2A The current waveforms shown are similar. The first stage lasts approximately tens of μs, during which the first switch S1 is turned on, and the first capacitor C1 and the first inductor L1 resonate and discharge, with a peak current of approximately tens of kA and a resonant frequency of approximately several kHz. In this first stage, the direction of the discharge current flow is as follows... Figure 5A As shown in the figure, the negative direction is defined, meaning that the current flowing through the inductive load in this stage is negative and the absolute value gradually increases.

[0060] Figure 5B Corresponding to the second stage, such as the PI stage, its specific details are... Figure 2B The current waveforms shown are similar. In this stage, the first switch S1 remains closed, the second switch S2 is closed, and the equivalent capacitance formed by the series connection of the second capacitor C2 and the third capacitor C3, along with the parasitic inductance of the link, resonates. The peak-to-peak value of the resonant current is tens of kA, and the resonant frequency is tens of kHz or higher. Since the capacitance of the third capacitor C3 is much larger than that of the second capacitor C2—for example, the capacitance of the third capacitor C3 is more than ten times that of the second capacitor C2—the resonant frequency is mainly determined by the capacitance of the second capacitor C2. In this second stage, the resonant current flowing through the second switch S2 flows through the second capacitor C2 and the third capacitor C3. The direction of the discharge current flow is as follows: Figure 5B As shown, it is still in the negative direction, that is, the current flowing through the inductive load LD in this stage is negative, and since the resonant frequency is larger than that in the first stage, the absolute value of the current can be seen to oscillate and change.

[0061] Figure 5C Corresponding to the third stage, such as the Main stage, the first switch S1 and the second switch S2 remain on, while the third switch S3 is on. Therefore, in addition to the resonant operation associated with the second capacitor C2, the third capacitor C3 also resonates and discharges with the parasitic inductance of the link (not shown). This parasitic inductance may differ from that in the second stage. Since the on-resistance of the third switch S3 is relatively small, the resonant discharge current of the third capacitor C3 can easily flow through it. In this stage, since the second switch S2 remains on, the resonant current flowing through the second switch S2 and the resonant current flowing through the third switch S3 simultaneously flow through the third capacitor C3. The resonant frequency of the resonant discharge between the third capacitor C3 and the parasitic inductance of the link (not shown) is lower than that in the second stage but higher than that in the first stage. Furthermore, the discharge current provided by the third switch circuit 330 flows through the third capacitor C3 and the third switch S3, causing the current supplied to the inductive load LD to rapidly rise from a negative current value to a positive current value, reaching a peak value of over 100 kA in a time of several μs.

[0062] Figure 5DCorresponding to the fourth stage, such as the Crowbar stage, the first switch S1, the second switch S2, and the third switch S3 remain closed, while the fourth switch S4 is closed. Therefore, the inductive load LD is short-circuited, and the current in the inductive load LD gradually decreases from its positive peak, forming a pulse current, thus ending the discharge. Depending on the circuit parameter design, the current flowing through the fourth switch S4 in the fourth stage can be essentially equivalent to the freewheeling current of the inductive load LD.

[0063] Here, when the second switch S2 of the second switch branch 320 is turned on, the first switch S1 remains on, therefore the first switch branch 310 remains open. Consequently, the second discharge current supplied to the inductive load LD in the second stage may be the sum of the discharge currents supplied to the inductive load LD by both switch branches, depending on the design parameters of the circuit elements in each switch branch. Therefore, the discharge current supplied to the inductive load LD by the second switch branch 320 in the second stage may be part or all of the second discharge current supplied to the inductive load LD. Similarly, the discharge current supplied to the inductive load LD by the third switch branch 330 in the third stage may be part or all of the third discharge current supplied to the inductive load LD. Likewise, the freewheeling current flowing through the fourth switch branch 340 in the fourth stage is part or all of the freewheeling current of the inductive load LD.

[0064] Therefore, based on Figure 3 The pulsed power supply shown reduces parasitic inductance and resistance in the link by partially integrating the second and third switching branches (sharing a capacitor), thereby reducing the oscillation risk and power system losses, and thus improving efficiency.

[0065] Furthermore, it was observed that in the second stage, the second capacitor C2 and the third capacitor C3 are connected in series, and the resonant current flows through both capacitors C2 and C3. Therefore, the energy required for the discharge process in the second stage can be provided by the third capacitor C3, without the need to pre-charge the second capacitor C2 or charge it to the high voltage required by the first capacitor C1 and the third capacitor C3. In other words, in the second stage, the second capacitor C2 mainly provides a smaller capacitance value so that the resonant frequency can meet the oscillation frequency requirements of the discharge current provided in the second stage, while the required energy can be provided by the third capacitor C3. Therefore, there are not many requirements for the pre-charge voltage value of the second capacitor C2.

[0066] Therefore, in some embodiments, three charging power supplies are still provided, but the power supply voltage of the second charging power supply Vdc2 for the second capacitor C2 can be a low-voltage DC power supply. For example, the absolute value of the power supply voltage of the first charging power supply Vdc1 for the first capacitor C1 and the third charging power supply Vdc3 for the third capacitor C3 is more than ten times the absolute value of the power supply voltage of the second charging power supply Vdc2 for the second capacitor C2. Alternatively, the second charging power supply Vdc2 and the corresponding charging switch Br2 can be omitted.

[0067] Therefore, compared to traditional pulse power supplies, besides reducing parasitic inductance and resistance in the power supply chain, thus lowering the risk of power system oscillation and losses and improving efficiency, the charging voltage of the second capacitor is much lower than that of the first and third capacitors. This means the voltage requirements for the power supply and switch in the charging circuit of the second capacitor are lower. Furthermore, the charging power supply and switch for the second capacitor can even be eliminated, further simplifying the power system and reducing system cost.

[0068] According to another aspect of this disclosure, a pulse power supply system is also provided.

[0069] A pulse power supply system may include a pulse power supply and an inductive load. The pulse power supply may be as described in the previous reference. Figure 3 , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Figure 5C and Figure 5D The various pulse power supplies 300 described, and / or inductive loads, can be as referenced above. Figure 3 , Figure 4A , Figure 4B , Figure 5A , Figure 5B , Figure 5C The diagram illustrates an inductive load, such as an θ-pinch coil.

[0070] In this disclosure, the terms "first" and "second," etc., are used only to distinguish various elements and do not indicate any order, importance, or priority.

[0071] Even if a particular combination of features is defined in the claims and / or disclosed in the specification, such combinations are not intended to limit the disclosure of aspects. In fact, many of these features can be combined in ways that are not defined in the claims and / or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of aspects includes every dependent claim in combination with every other claim in the claim set.

[0072] The embodiments of this disclosure described in detail above are merely illustrative and not restrictive. Those skilled in the art will understand that various modifications and combinations can be made to these embodiments or their features without departing from the principles and spirit of this disclosure, and such modifications should fall within the scope of this disclosure.

Claims

1. A pulse power supply, comprising: The first switching branch is configured to turn on in the first stage, so that the pulse power supply provides a first discharge current to the inductive load; The second switching branch is configured to turn on in the second stage, so that the pulse power supply provides a second discharge current to the inductive load. The third switch branch is configured to turn on in the third stage, so that the pulse power supply provides a third discharge current to the inductive load. as well as The fourth switching branch is configured to turn on in the fourth stage, enabling the pulsed power supply to provide a freewheeling path for the inductive load. The first, second, third, and fourth switch branches are connected in parallel across the inductive load, and the second and third switch branches share the same energy storage capacitor.

2. The pulse power supply according to claim 1, wherein: The first switching branch includes a first switch, a first capacitor, and an inductor connected in series. The second switch branch includes a second switch, a second capacitor, and a third capacitor connected in series. The third switch branch includes a third switch and a third capacitor connected in series. The third capacitor is a shared energy storage capacitor used by the second and third switch branches. The fourth switch branch includes the fourth switch.

3. The pulse power supply according to claim 2, wherein, The first capacitor has a matching first charging power supply and a first charging switch, and the third capacitor has a matching third charging power supply and a third charging switch.

4. The pulse power supply according to claim 3, wherein, The second capacitor does not have a matching second charging power supply and a second charging switch.

5. The pulse power supply according to claim 3, wherein, The second capacitor has a matching second charging power supply and a second charging switch, and The absolute values ​​of the power supply voltages of the first and third charging power supplies are more than ten times the absolute value of the power supply voltage of the second charging power supply. During the pre-charging phase prior to the first stage, the first charging switch, the second charging switch, and the third charging switch are turned on to pre-charge the corresponding capacitors using their respective charging power supplies.

6. The pulse power supply according to claim 2, wherein, In the second stage, the resonant current flowing through the second switch flows through the second and third capacitors connected in series, and In the third stage, the resonant current flowing through the second switch and the resonant current flowing through the third switch simultaneously flow through the third capacitor.

7. The pulse power supply according to claim 2, wherein, The capacitance of the third capacitor is more than ten times that of the second capacitor.

8. The pulse power supply according to claim 2, wherein, In the second stage, the equivalent capacitance formed by the series connection of the second and third capacitors resonates with the parasitic inductance of the link, and In the third stage, the third capacitor also resonates with the parasitic inductance of the link.

9. The pulse power supply according to claim 2, wherein, Each of the first, second, third, and fourth switches is a thyristor, a thyristor, a gas switch, or a semiconductor switch.

10. The pulse power supply according to claim 1, wherein, The pulsed power supply is used in a field inversion configuration (FRC) fusion device, and the inductive load is a θ-pinch coil. The first to fourth stages correspond to the plasma bias stage, pre-ionization stage, main field stage, and follow-through / crowbar stage, respectively.

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