Bidirectional controllable fault current limiter and bidirectional controllable fault current limiter control method

Abstract

The application provides a bidirectional controllable fault current limiter and a bidirectional controllable fault current limiter control method. The bidirectional controllable fault current limiter comprises a main flow branch, a commutation branch and a current limiting branch. The main flow branch is used to provide an electric energy flow path when the current value of the current in the DC line is less than or equal to a preset current value. The main flow branch comprises a first bridge arm and a second bridge arm, and the half-controlled devices in the first bridge arm and the second bridge arm are arranged in opposite directions. The commutation branch is used to transfer the current from the main flow branch to the current limiting branch when the current value of the current in the DC line is greater than the preset current value. The current limiting branch is used to provide an electric energy flow path when the current value of the current in the DC line is greater than the preset current value, and the impedance in the current limiting branch is greater than the impedance in the main flow branch. Through the application, the cost of the bidirectional fault current limiter is reduced, and the topology structure is simplified.

Description

Technical Field

[0001] This invention relates to the field of power electronics, and more particularly to a bidirectional controllable fault current limiter and a bidirectional controllable fault current limiter control method. Background Technology

[0002] Compared to conventional DC transmission, flexible DC transmission features lower harmonics and no commutation failures, attracting widespread attention in high-voltage, high-capacity power conversion applications. During operation, the converter station exhibits voltage source characteristics. Without current limiting measures, DC-side faults will cause a rapid rise in short-circuit current, which lacks a natural zero-crossing point and has a high peak value. This places extremely high demands on the DC protection system in terms of operating time, reliability, and breaking capacity. A well-designed fault current limiter can reduce the rise time and peak value of the short-circuit current, providing more time for the protection system to make operational decisions and reducing the current stress on the DC circuit breaker. However, existing bidirectional current-limiting fault current limiters use fully controlled devices, resulting in higher losses and construction costs, and complex topologies. Summary of the Invention

[0003] To reduce the cost of bidirectional fault current limiters and simplify the topology, this invention proposes a bidirectional controllable fault current limiter and a control method for the bidirectional controllable fault current limiter.

[0004] In a first aspect, the present invention provides a bidirectional controllable fault current limiter, which includes: a main flow branch, a commutation branch and a current limiting branch;

[0005] The main current branch is used to provide a path for electrical energy flow when the current value in the DC line is less than or equal to a preset current value. The main current branch includes a first bridge arm and a second bridge arm. Both the first bridge arm and the second bridge arm include semi-controlled devices. The semi-controlled devices in the first bridge arm and the semi-controlled devices in the second bridge arm are set in opposite directions.

[0006] The commutation branch is used to transfer the current from the main current-carrying branch to the current-limiting branch when the current value in the DC line is greater than the preset current value.

[0007] A current-limiting branch is used to provide a path for electrical energy to flow when the current value in the DC line is greater than a preset current value. The impedance in the current-limiting branch is greater than the impedance in the main current-flow branch.

[0008] Considering that existing bidirectional current limiting fault current limiters use fully controlled devices, resulting in high losses and construction costs, as well as complex topologies, the bidirectional controllable fault current limiter provided by this invention uses a first and second bridge arm composed of semi-controlled devices in the main current branch. When the current direction in the DC line is different, the corresponding bridge arm is activated to achieve bidirectional current limiting and suppress fault current in the DC line. This simplifies the topology and reduces the losses and construction costs of the bidirectional fault current limiter.

[0009] In conjunction with the first aspect, in the first embodiment of the first aspect, the first bridge arm and the second bridge arm in the main flow branch are connected in series;

[0010] The first bridge arm includes a first thyristor and a first diode;

[0011] The cathode of the first thyristor is connected to the anode of the first diode, and the anode of the first thyristor is connected to the cathode of the first diode.

[0012] The second bridge arm includes a second thyristor and a second diode;

[0013] The cathode of the second thyristor is connected to the anode of the second diode, and the anode of the second thyristor is connected to the cathode of the second diode.

[0014] In conjunction with the first embodiment of the first aspect, in the second embodiment of the first aspect, the commutation branch includes a commutation capacitor and a third thyristor, which are connected in series.

[0015] The positive terminal of the commutation capacitor is connected to the anode of the third thyristor, the cathode of the third thyristor is connected to the anode of the first diode and the anode of the second diode, and the negative terminal of the commutation capacitor is connected to the connection point of the first and second bridge arms in the main current path.

[0016] In conjunction with the second embodiment of the first aspect, in the third embodiment of the first aspect, the current-limiting branch includes a first energy-consuming element and a second energy-consuming element;

[0017] The first energy-consuming element is disposed between the cathode of the third thyristor and the anode of the first diode;

[0018] The second energy-consuming element is located between the cathode of the third thyristor and the anode of the second diode.

[0019] Secondly, the present invention also provides a bidirectional controllable fault current limiter control method for the bidirectional controllable fault current limiter in the first aspect or any embodiment of the first aspect, the method comprising:

[0020] To obtain the current value and current direction in a DC line;

[0021] Based on the current flow direction, turn on the semi-controlled device in the effective bridge arm of the main current branch. The effective bridge arm is the first bridge arm or the second bridge arm.

[0022] When the current value is greater than the preset current value, the commutation branch is opened, which releases the current. The current released by the commutation branch turns off the effective bridge arm in the main current-passing branch until the commutation branch is turned off, so that the current in the DC line can flow to the current-limiting branch.

[0023] Considering that existing bidirectional current limiting fault current limiters use fully controlled devices, resulting in high losses and construction costs, as well as complex topologies, the bidirectional controllable fault current limiter control method provided by this invention enables the effective bridge arm in the main current-carrying branch to be activated when the current direction in the DC line is different, thereby achieving bidirectional current limiting and suppressing fault current in the DC line. This simplifies the topology while reducing the losses and construction costs of the bidirectional fault current limiter.

[0024] In conjunction with the second aspect, in the first embodiment of the second aspect, according to the current flow direction, activating the effective bridge arm in the main current-carrying branch includes:

[0025] When the current flows from the first bridge arm to the second bridge arm in the main current path, a trigger pulse is provided for the second thyristor of the second bridge arm.

[0026] In conjunction with the second aspect, in the second embodiment of the second aspect, according to the current flow direction, activating the effective bridge arm in the main current-carrying branch includes:

[0027] When the current flows from the second bridge arm to the first bridge arm in the main current path, a trigger pulse is provided to the first thyristor of the first bridge arm.

[0028] Thirdly, the present invention also provides a bidirectional controllable fault current limiter control device for use in the bidirectional controllable fault current limiter control method in the second aspect or any embodiment of the second aspect, the device comprising:

[0029] The acquisition module acquires the current value and current direction in the DC line.

[0030] The first activation module is used to activate the semi-controlled device in the effective bridge arm of the main current flow branch according to the current flow direction. The effective bridge arm is the first bridge arm or the second bridge arm.

[0031] The second activation module is used to activate the commutation branch when the current value is greater than the preset current value, so that the commutation branch releases current and the effective bridge arm in the main current-passing branch is turned off by the current released by the commutation branch until the commutation branch is turned off, so that the current in the DC line flows to the current-limiting branch.

[0032] Considering that existing bidirectional current limiting fault current limiters use fully controlled devices, resulting in high losses and construction costs, as well as complex topologies, the bidirectional controllable fault current limiter control device provided by this invention opens the effective bridge arm in the main current-carrying branch when the current direction in the DC line is different, thereby achieving bidirectional current limiting and suppressing fault current in the DC line. This simplifies the topology while reducing the losses and construction costs of the bidirectional fault current limiter.

[0033] Fourthly, the present invention also provides a computer device, including a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the steps of the bidirectional controllable fault current limiter control method of the second aspect or any embodiment of the second aspect.

[0034] Fifthly, the present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the bidirectional controllable fault current limiter control method of the second aspect or any embodiment of the second aspect. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a circuit diagram of a bidirectional controllable fault current limiter according to an exemplary embodiment;

[0037] Figure 2 This is a flowchart of a bidirectional controllable fault current limiter control method according to an exemplary embodiment;

[0038] Figure 3 This is a circuit diagram in which current flows into the fault current limiter from port P1 and out from port P2 when the current value in the DC line is less than or equal to the preset current value.

[0039] Figure 4 This is a circuit diagram in which current flows into the fault current limiter from port P2 and out from port P1 when the current value in the DC line is less than or equal to the preset current value.

[0040] Figure 5 This is a circuit diagram in one example where, when the current value in the DC line is greater than the preset current value, the current flows in from port P1 of the fault current limiter and flows out from port P2.

[0041] Figure 6 This is an example of a circuit diagram showing how current flows through a current-limiting branch when the current in the DC line exceeds a preset current value.

[0042] Figure 7 This is a schematic diagram of a bidirectional controllable fault current limiter control device according to an exemplary embodiment.

[0043] Figure 8 This is a schematic diagram of the hardware structure of a computer device according to an exemplary embodiment. Detailed Implementation

[0044] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0045] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] To reduce the cost of bidirectional fault current limiters and simplify the topology, this invention proposes a bidirectional controllable fault current limiter and a control method for the bidirectional controllable fault current limiter.

[0047] Figure 1 This is a circuit diagram of a bidirectional controllable fault current limiter according to an exemplary embodiment. The fault current limiter includes: a main flow branch 1, a commutation branch 2, and a current limiting branch 3.

[0048] Mainstream branch 1 is used to provide a power flow path when the current value in the DC line is less than or equal to a preset current value. Mainstream branch 1 includes a first bridge arm 4 and a second bridge arm 5. Both the first bridge arm 4 and the second bridge arm 5 include semi-controlled devices. The semi-controlled devices in the first bridge arm 4 and the semi-controlled devices in the second bridge arm 5 are arranged in opposite directions.

[0049] In an optional embodiment, by setting semi-controlled devices with opposite directions in the main current branch 1, different semi-controlled devices are activated in the main current branch 1 when the current flow direction in the branch line is different. Depending on the current flow direction, the semi-controlled device in the first bridge arm 4 or the second bridge arm 5 of the main current branch 1 is activated to achieve bidirectional current limiting.

[0050] In one alternative embodiment, the semi-controlled device is a thyristor.

[0051] In an optional embodiment, the preset current value can be set according to actual needs.

[0052] The commutation branch 2 is used to transfer the current from the main current branch 1 to the current limiting branch 3 when the current value in the DC line is greater than the preset current value.

[0053] In an optional embodiment, when the current value in the DC line is greater than the preset current value, it is considered that there is a fault current in the DC line. The fault current limiter increases the impedance in the branch line by transferring the current from the main current branch 1 to the current limiting branch 3, thereby limiting the fault current.

[0054] In an optional embodiment, the commutation branch 2 includes a commutation capacitor and a thyristor. Discharging the commutation capacitor turns off the semi-controlled device in the main current-pass branch, transferring the fault current from the main current-pass branch 1 to the current-limiting branch 3.

[0055] The current limiting branch 3 is used to provide a path for electrical energy flow when the current value in the DC line is greater than the preset current value. The impedance in the current limiting branch 3 is greater than the impedance in the main current flow branch 1.

[0056] Considering that existing bidirectional current limiting fault current limiters use fully controlled devices, resulting in high losses and construction costs, as well as complex topologies, the bidirectional controllable fault current limiter provided by this invention uses a first bridge arm 4 and a second bridge arm 5 composed of semi-controlled devices in the main current branch 1. When the current direction in the DC line is different, the corresponding bridge arm is opened to achieve bidirectional current limiting and suppress fault current in the DC line. This simplifies the topology and reduces the losses and construction costs of the bidirectional fault current limiter.

[0057] exist Figure 1 In the main branch road 1, the first bridge arm 4 and the second bridge arm 5 are connected in series.

[0058] The first bridge arm 4 includes a first thyristor S2 and a first diode D1; the cathode of the first thyristor S2 is connected to the anode of the first diode D1, and the anode of the first thyristor S2 is connected to the cathode of the first diode D1.

[0059] The second bridge arm 5 includes a second thyristor S1 and a second diode D2; the cathode of the second thyristor S1 is connected to the anode of the second diode D2, and the anode of the second thyristor S1 is connected to the cathode of the second diode D2.

[0060] In an optional embodiment, the number of first thyristors S2 and second thyristors S1 in the same bridge arm can be determined according to actual needs and is not specifically limited here. The connection method between multiple first thyristors / second thyristors in the same bridge arm can be set to series or parallel as needed.

[0061] like Figure 1 As shown, commutation branch 2 includes a commutation capacitor C and a third thyristor S3, which are connected in series. Before use, the commutation capacitor C needs to be pre-charged. When a fault current exists in the DC line, a trigger pulse is applied to the third thyristor S3. The current released through the discharge of the commutation capacitor C turns off the semi-controlled device in the main current path branch 1, allowing commutation branch 2 to transfer the fault current from the main current path branch 1 to the current limiting branch 3, thus realizing the fault current commutation process.

[0062] In an optional embodiment, the number of third thyristors S3 in the commutation branch 2 can be determined according to actual needs and is not specifically limited here. The connection method between multiple third thyristors S3 can be set to series or parallel as needed.

[0063] The positive terminal of the commutation capacitor C is connected to the anode of the third thyristor S3. The cathode of the third thyristor S3 is connected to the anode of the first diode D1 and the anode of the second diode D2, respectively. The negative terminal of the commutation capacitor C is connected to the connection point of the first bridge arm 4 and the second bridge arm 5 in the main current branch 1.

[0064] In an optional embodiment, the current-limiting branch 3 includes a first energy-consuming element R1 and a second energy-consuming element R2.

[0065] like Figure 1 As shown, when the current value in the DC line exceeds the preset current value, a fault current is considered to exist in the DC line. During the entire process of the commutation branch 2 transferring the current from the main current-carrying branch 1 to the current-limiting branch 3, the impedance in the DC line is increased through energy-consuming components. This ensures that the fault current limiter effectively limits the fault current at the initial moment of fault current detection, shortening the response time of the fault current limiter and providing more operating time for the DC protection system. Simultaneously, the high voltage problem caused by circulating current failure does not occur during the entire process of transferring the fault current from the main current-carrying branch 1 to the current-limiting branch 3, thus enhancing reliability.

[0066] In an optional embodiment, the first energy-consuming element R1 / the second energy-consuming element R2 can be selected as a resistor element, and the number of resistor elements can be set according to actual needs, without specific limitations.

[0067] The first energy-consuming element R1 is disposed between the cathode of the third thyristor S3 and the anode of the first diode D1.

[0068] The second energy-consuming element R2 is disposed between the cathode of the third thyristor S3 and the anode of the second diode D2.

[0069] Figure 2This is a bidirectional controllable fault current limiter control method proposed according to an exemplary embodiment, used for the bidirectional controllable fault current limiter in the above embodiment, the method including the following steps S201 to S203:

[0070] Step S201: Obtain the current value and current direction in the DC line.

[0071] In one alternative embodiment, the current flow direction includes two directions: from the first bridge arm 4 to the second bridge arm 5 in the main current branch 1 and from the second bridge arm 5 to the first bridge arm 4 in the main current branch 1.

[0072] Step S202: According to the current flow direction, turn on the semi-controlled device in the effective bridge arm of the main current branch 1. The effective bridge arm is the first bridge arm 4 or the second bridge arm 5.

[0073] In an optional embodiment, when the current flows from the first bridge arm 4 in the main current path 1 to the second bridge arm 5, a trigger pulse is provided to the second thyristor S1 of the second bridge arm 5.

[0074] In an optional embodiment, when the current flows from the second bridge arm 5 in the main current path 1 to the first bridge arm 4, a trigger pulse is provided to the first thyristor S2 of the first bridge arm 4.

[0075] Step S203: When the current value is greater than the preset current value, the commutation branch 2 is turned on, so that the commutation branch 2 releases the current. The effective bridge arm in the main current flow branch 1 is turned off by the current released by the commutation branch 2 until the commutation branch 2 is turned off, so that the current in the DC line flows to the current limiting branch 3.

[0076] In an optional embodiment, when the current value is greater than a preset current value, a trigger pulse is provided to the third thyristor S3 in commutation branch 2, turning on commutation branch 2. The commutation capacitor C in commutation branch 2 begins to discharge, causing the thyristor in the effective bridge arm to turn off because the forward current is less than the holding current. When the voltage polarity of the commutation capacitor C changes, and the current in the third thyristor S3 is less than the holding current for a period of time, the third thyristor S3 automatically turns off, i.e., commutation branch 2 automatically turns off. This achieves the transfer of fault current from the main current-carrying branch 1 to the current-limiting branch 3.

[0077] Considering that existing bidirectional current limiting fault current limiters use fully controlled devices, resulting in high losses and construction costs, as well as complex topologies, the bidirectional controllable fault current limiter control method provided by this invention enables the effective bridge arm in the main current-carrying branch 1 to be activated when the current direction in the DC line is different, thereby achieving bidirectional current limiting and suppressing fault current in the DC line. This simplifies the topology while reducing the losses and construction costs of the bidirectional fault current limiter.

[0078] Figure 3This is a circuit diagram showing that when the current value in the DC line is less than or equal to the preset current value, the current flows into the fault current limiter from port P1 and out from port P2. When the current value in the DC line is less than or equal to the preset current value, the DC line is considered to be in normal operation. A trigger pulse is given to the second thyristor S1 in the second bridge arm 5, the main current flow branch 1 is turned on, and the current in the DC line flows into the fault current limiter from the input terminal P1, passes through the first diode D1 and the second thyristor S1 in the main current flow branch 1 of the fault current limiter in sequence, and flows out from the output terminal P2 of the fault current limiter.

[0079] Figure 4 This is a circuit diagram showing that when the current value in the DC line is less than or equal to the preset current value, the current flows into the fault current limiter from port P2 and out from port P1. When the current value in the DC line is less than or equal to the preset current value, the DC line is considered to be in normal operation. A trigger pulse is given to the first thyristor S2 in the first bridge arm 4, and the main current flow branch 1 is turned on. The current in the DC line flows into the fault current limiter from the input terminal P2, passes through the second diode D2 and the first thyristor S2 in the main current flow branch 1 of the fault current limiter in sequence, and flows out from the output terminal P1 of the fault current limiter.

[0080] Figure 5 This is a circuit diagram showing that when the current in the DC line exceeds a preset current value, current flows into the fault current limiter from port P1 and out from port P2. When the detected current value exceeds the preset current value, a fault current is considered to exist in the DC line. A trigger signal is provided to the third thyristor S3 in commutation branch 2, opening commutation branch 2. The commutation capacitor C begins to discharge. At this time, the current flow direction in the DC line is P1→D1→C→S3→R2→P2 and P1→D1→S1→P2. The discharge circuit of commutation capacitor C is C's positive terminal → S3→R2→D2→C's negative terminal and C's positive terminal → S3→R1→D1→C's negative terminal. The discharge current of commutation capacitor C causes the second thyristor S1 in the second bridge arm 5 to turn off because the forward current is less than the holding current. When the voltage polarity of the commutation capacitor C changes, and the current in the third thyristor S3 is less than the holding current for a period of time, the third thyristor S3 automatically turns off, that is, the commutation branch 2 automatically turns off. This transfers the fault current from the main current-carrying branch 1 to the current-limiting branch 3, thus achieving fault current commutation. At this time, the current flow direction in the DC line is P1→R1→R2→P2, as follows... Figure 6 As shown. Similarly, when the current value in the DC line is greater than the preset current value, the current flows in from port P2 of the fault current limiter and flows out from port P1. The principle is similar to the principle of the current flowing in from port P1 and out from port P2 of the fault current limiter, and will not be elaborated here.

[0081] Based on the same inventive concept, embodiments of the present invention also provide a bidirectional controllable fault current limiter control device, such as... Figure 7 As shown, the device includes:

[0082] The acquisition module 701 acquires the current value and current direction of the DC line; for details, please refer to the description of step S101 in the above embodiment, which will not be repeated here.

[0083] The first activation module 702 is used to activate the semi-controlled device in the effective bridge arm of the main current flow branch 1 according to the current flow direction. The effective bridge arm is the first bridge arm 4 or the second bridge arm 5. For details, please refer to the description of step S102 in the above embodiment, which will not be repeated here.

[0084] The second activation module 703 is used to activate the commutation branch 2 when the current value is greater than a preset current value, causing the commutation branch 2 to release current. The current released by the commutation branch 2 turns off the effective bridge arm in the main current-carrying branch 1 until the commutation branch 2 is turned off, allowing the current in the DC line to flow to the current-limiting branch 3. For details, please refer to the description of step S103 in the above embodiment, which will not be repeated here.

[0085] In one example, in the first enabling module 702, the active bridge arm in the main current tributary 1 is enabled via the following submodule:

[0086] The first activation submodule is used to provide a trigger pulse to the second thyristor S1 of the second bridge arm 5 when the current flows from the first bridge arm 4 to the second bridge arm 5 in the main current path 1. For details, please refer to the description in the above embodiments, which will not be repeated here.

[0087] In one example, in the first enabling module 702, the active bridge arm in the main current tributary 1 is enabled via the following submodule:

[0088] The second activation submodule is used to provide a trigger pulse to the first thyristor S2 of the first bridge arm 4 when the current flows from the second bridge arm 5 in the main current branch 1 to the first bridge arm 4. For details, please refer to the description in the above embodiments, which will not be repeated here.

[0089] The specific limitations and beneficial effects of the aforementioned device can be found in the above description of the control method for the bidirectional controllable fault current limiter, and will not be repeated here. Each of the above modules can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in or independent of the processor in a computer device, or stored in the memory of a computer device as software, so that the processor can call and execute the corresponding operations of each module.

[0090] Figure 8This is a schematic diagram of the hardware structure of a computer device according to an exemplary embodiment. For example... Figure 8 As shown, the device includes one or more processors 810 and a memory 820, the memory 820 including persistent memory, volatile memory, and a hard disk. Figure 8 Taking a processor 810 as an example, the device may also include an input device 830 and an output device 840.

[0091] The processor 810, memory 820, input device 830, and output device 840 can be connected via a bus or other means. Figure 8 Taking the example of a connection between China and Israel via a bus.

[0092] Processor 810 can be a Central Processing Unit (CPU). Processor 810 can also be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, or combinations thereof. The general-purpose processor can be a microprocessor or any conventional processor.

[0093] The memory 820, as a non-transitory computer-readable storage medium, includes persistent memory, volatile memory, and a hard disk. It can be used to store non-transitory software programs, non-transitory computer-executable programs, and modules, such as the program instructions / modules corresponding to the bidirectional controllable fault current limiter control method in this embodiment. The processor 810 executes various server functions and data processing by running the non-transitory software programs, instructions, and modules stored in the memory 820, thereby implementing any of the above-mentioned bidirectional controllable fault current limiter control methods.

[0094] The memory 820 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data that is needed and required. Furthermore, the memory 820 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 820 may optionally include memory remotely located relative to the processor 810, and these remote memories can be connected to the data processing device via a network. Examples of such networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof.

[0095] Input device 830 can receive input digital or character information, and generate signal inputs related to user settings and function control. Output device 840 may include display devices such as a display screen.

[0096] One or more modules are stored in memory 820, and when executed by one or more processors 810, they perform actions such as... Figure 2 The method shown.

[0097] The above-described product can execute the method provided in the embodiments of the present invention, and has the corresponding functional modules and beneficial effects for executing the method. Technical details not described in detail in this embodiment can be found in [reference 1]. Figure 2 The relevant descriptions in the illustrated embodiments.

[0098] This invention also provides a non-transitory computer storage medium storing computer-executable instructions that can execute the control methods described in any of the above-described method embodiments. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), random access memory (RAM), flash memory, hard disk drive (HDD), or solid-state drive (SSD), etc.; the storage medium may also include combinations of the above types of memory.

[0099] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0100] The above are merely specific embodiments of the present invention, enabling those skilled in the art to understand or implement the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A bidirectional controllable fault current limiter, characterized in that, The fault current limiter includes: a main flow branch, a commutation branch, and a current limiting branch; The main current branch is used to provide a path for electrical energy flow when the current value in the DC line is less than or equal to a preset current value. The main current branch includes a first bridge arm and a second bridge arm. Both the first bridge arm and the second bridge arm include semi-controlled devices. The semi-controlled devices in the first bridge arm and the semi-controlled devices in the second bridge arm are arranged in opposite directions. The commutation branch is used to transfer current from the main current-carrying branch to the current-limiting branch when the current value in the DC line is greater than the preset current value. The current-limiting branch is used to provide a path for electrical energy flow when the current value in the DC line is greater than a preset current value, and the impedance in the current-limiting branch is greater than the impedance in the main current-flow branch. The first bridge arm and the second bridge arm in the main branch are connected in series; The first bridge arm includes a first thyristor and a first diode; The cathode of the first thyristor is connected to the anode of the first diode, and the anode of the first thyristor is connected to the cathode of the first diode. The second bridge arm includes a second thyristor and a second diode; The cathode of the second thyristor is connected to the anode of the second diode, and the anode of the second thyristor is connected to the cathode of the second diode. The commutation branch includes a commutation capacitor and a third thyristor, which are connected in series. The positive terminal of the commutation capacitor is connected to the anode of the third thyristor, the cathode of the third thyristor is connected to the anode of the first diode and the anode of the second diode, and the negative terminal of the commutation capacitor is connected to the connection point of the first bridge arm and the second bridge arm in the main current path. The current-limiting branch includes a first energy-consuming element and a second energy-consuming element; The first energy-consuming element is disposed between the cathode of the third thyristor and the anode of the first diode; The second energy-consuming element is disposed between the cathode of the third thyristor and the anode of the second diode.

2. A bidirectional controllable fault current limiter control method, characterized in that, The method for the bidirectional controllable fault current limiter of claim 1 includes: To obtain the current value and current direction in a DC line; According to the current flow direction, the semi-controlled device in the effective bridge arm of the main current branch is turned on, wherein the effective bridge arm is the first bridge arm or the second bridge arm. When the current value is greater than the preset current value, the commutation branch is opened, so that the commutation branch releases current. The current released by the commutation branch turns off the effective bridge arm in the main current-passing branch until the commutation branch is turned off, so that the current in the DC line flows to the current-limiting branch.

3. The method according to claim 2, characterized in that, Based on the current flow direction, activate the effective bridge arm in the main current-carrying branch, including: When the current flows from the first bridge arm to the second bridge arm in the main current path, a trigger pulse is provided to the second thyristor of the second bridge arm.

4. The method according to claim 2, characterized in that, Based on the current flow direction, activate the effective bridge arm in the main current-carrying branch, including: When the current flows from the second bridge arm to the first bridge arm in the main current path, a trigger pulse is provided to the first thyristor of the first bridge arm.

5. A bidirectional controllable fault current limiter control device, characterized in that, The bidirectional controllable fault current limiter control method according to any one of claims 2-4, the apparatus comprising: The acquisition module acquires the current value and current direction in the DC line. The first activation module is used to activate the semi-controlled device in the effective bridge arm of the main current flow branch according to the current flow direction. The effective bridge arm is either the first bridge arm or the second bridge arm. The second activation module is used to activate the commutation branch when the current value is greater than the preset current value, so that the commutation branch releases current and the effective bridge arm in the main current-passing branch is turned off by the current released by the commutation branch until the commutation branch is turned off, so that the current in the DC line flows to the current-limiting branch.

6. A computer device, characterized in that, The device includes a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the steps of the bidirectional controllable fault current limiter control method according to any one of claims 2-4.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by the processor, it implements the steps of the bidirectional controllable fault current limiter control method as described in any one of claims 2-4.

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