Hybrid DC circuit breaker and control method thereof
Through the design and control method of fault current, the safety of mechanical switch and the stability of fault current are achieved.
Patent Information
- Application Number
- CN202510810429.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-09-19
AI Technical Summary
In the current transfer process of existing hybrid DC circuit breakers, the mechanical switches are subjected to high arcing voltage, resulting in problems with operational safety and low commutation speed.
The structure design adopts parallel main current branch, current transfer branch and regulation branch, including regulating capacitor and anti-parallel thyristor. By controlling the on and off of IGBT and thyristor during fault current, forward and reverse oscillating current is formed to reduce the arcing pressure of mechanical switch, and the fault current is released through the energy dissipation branch.
It effectively reduces the arcing voltage of the mechanical switch, improves the safety of the mechanical switch and the transfer process of the fault current, realizes the safety and reliability of the mechanical switch and the stability of the fault current during the commutation process.
Smart Images
Figure CN120675002A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of direct current circuit breakers, and in particular to a hybrid direct current circuit breaker and a control method thereof. Background Art
[0002] Against the backdrop of ever-increasing energy demand and continuous optimization of the energy mix, the power system is undergoing profound transformation and development. As DC transmission technology demonstrates significant advantages in long-distance, high-capacity power transmission, renewable energy integration, and urban grid power supply, its application is expanding. However, the inherent characteristics of DC systems also present a series of challenging issues for the design and operation of power equipment. Fault currents in DC systems rise extremely rapidly, and DC systems lack a natural zero-crossing point, making it difficult to extinguish fault currents once they occur. Traditional mechanical DC circuit breakers have long breaking times, large size, and high cost, while pure solid-state DC circuit breakers have high conduction losses and difficulty dissipating heat, often failing to meet practical application requirements. Hybrid DC circuit breakers combine the advantages of both, better addressing real-world applications. They offer fast breaking times and significantly reduced rated conduction losses.
[0003] For classic hybrid DC circuit breakers, when opening, the current needs to be commutated from the main current branch of the circuit breaker to the current transfer branch. This process is carried out by the arcing voltage of the mechanical switch. During this process, the mechanical switch is subjected to a high arcing voltage, which can easily cause damage to the switch.
[0004] Therefore, there is an urgent need to provide a hybrid DC circuit breaker and a control method thereof to reduce the arcing voltage during the current transfer from the main current branch to the current transfer process, speed up the commutation speed, and improve the safety of the hybrid DC circuit breaker. Summary of the Invention
[0005] In view of this, it is necessary to provide a hybrid DC circuit breaker and a control method thereof to solve the technical problem in the prior art that the arcing voltage of the mechanical switch is too high when the current is transferred to the current transfer branch, resulting in low safety and commutation speed.
[0006] In a first aspect, to solve the above-mentioned technical problems, the present invention provides a hybrid DC circuit breaker, comprising: a main current branch, a current transfer branch, and a regulating branch connected in parallel; the main current branch comprises a mechanical switch and a first IGBT connected in series; the current transfer branch comprises a second IGBT; the regulating branch comprises an anti-parallel thyristor, a first diode connected in parallel with the first IGBT, and a regulating capacitor; one end of the anti-parallel thyristor is connected to an input end of the mechanical switch, and the other end of the anti-parallel thyristor is connected between the first diode and the regulating capacitor; the anti-parallel thyristors comprise a first thyristor and a second thyristor connected in anti-parallel with the first thyristor; When a fault current occurs, receiving a first turn-off instruction generated by a host computer to instruct the first IGBT to turn off, a disconnection instruction to instruct the mechanical switch to disconnect, and a first turn-on instruction to instruct the second IGBT to turn on, wherein the disconnection instruction and the first turn-on instruction are generated after the first IGBT is turned off; The first IGBT is turned off in response to the first turn-off instruction, the mechanical switch is turned off in response to the disconnection instruction, and the second IGBT is turned on in response to the second turn-on instruction; After the second IGBT is turned on for a preset time, a second turn-on instruction generated by the host computer is received to instruct the first thyristor and the second thyristor to be turned on simultaneously, and the first thyristor and the second thyristor are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch; A second shutdown instruction instructing the second IGBT to shut down is received from the host computer when a reverse oscillation current is formed in the current transfer branch, and the second IGBT is shut down in response to the second shutdown instruction.
[0007] In a possible implementation, the hybrid DC circuit breaker further includes an energy dissipation branch connected in parallel with the main current branch. When the second IGBT is turned off, the fault current is released through the energy dissipation branch, thereby completing fault current removal.
[0008] In a possible implementation, the energy dissipation branch includes a lightning arrester.
[0009] In a possible implementation, the preset time length is 100 μs to 200 μs.
[0010] In one possible implementation, the main current branch further includes a second diode connected in series with the first IGBT, and a third IGBT and a third diode connected in parallel with the first IGBT; the current transfer branch further includes a fourth diode connected in series with the second IGBT, and a fourth IGBT and a fifth diode connected in parallel with the second IGBT; the regulation branch further includes a sixth diode connected in parallel with the first diode; The second diode and the third diode are in reverse direction, the first diode and the sixth diode are in reverse direction, and the fourth diode and the fifth diode are in reverse direction.
[0011] In a possible implementation, the mechanical switch is any one of a vacuum high-speed mechanical switch, an air high-speed mechanical switch, and an SF6 switch.
[0012] In a possible implementation, the arrester is at least one of a metal oxide arrester, a line-type metal oxide arrester, a gapless line-type metal oxide arrester, a fully insulated composite-jacketed metal oxide arrester, and a detachable arrester.
[0013] In a second aspect, the present invention further provides a control method for a DC circuit breaker, applicable to the hybrid DC circuit breaker described in any one of the possible implementations above, the control method comprising: Receiving a fault current occurrence instruction; In response to the fault current occurrence instruction, generating a first turn-off instruction instructing the first IGBT to turn off, an off instruction instructing the mechanical switch to open, and a first on instruction instructing the second IGBT to turn on, wherein the off instruction and the first on instruction are generated after the first IGBT is turned off; After the second IGBT is turned on for a preset time, a second turn-on instruction generated by the host computer is received to instruct the first thyristor and the second thyristor to be turned on simultaneously, and the first thyristor and the second thyristor are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch; A second shutdown instruction instructing the second IGBT to shut down is received from the host computer when a reverse oscillation current is formed in the current transfer branch, and the second IGBT is shut down in response to the second shutdown instruction.
[0014] The present invention provides the following beneficial effects: The hybrid DC circuit breaker provided by the present invention, by providing a regulating branch including a regulating capacitor, can accumulate a certain amount of energy when a fault current occurs, thereby regulating the voltage change in the current transfer branch during the shutdown process of the mechanical switch when the fault current occurs. Specifically, the regulating capacitor can provide a forward voltage drop during the commutation process from the mechanical switch to the current transfer branch, reducing the arcing pressure of the mechanical switch, accelerating the commutation process, and ensuring the safety of the hybrid DC circuit breaker during commutation. Furthermore, by providing an anti-parallel thyristor consisting of a first thyristor and a second thyristor connected in anti-parallel with the first thyristor, when the second IGBT is turned off, a reverse current can be generated based on the oscillation between the capacitor and the stray inductance, reducing the current in the current transfer branch, improving shutdown reliability, and thereby enhancing the stability of the hybrid DC circuit breaker.
[0015] Furthermore, the present invention can limit the direction of current flow by providing the first diode, ensuring that the regulating capacitor can only be charged in the forward direction of the current, thereby ensuring the regulating function of the regulating capacitor. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.
[0017] Figure 1 A schematic structural diagram of an embodiment of a hybrid DC circuit breaker provided by the present invention; Figure 2 A schematic diagram of current flow when no fault current occurs provided by the present invention; Figure 3 A schematic diagram of the current flow for charging the regulating capacitor when a fault current occurs provided by the present invention; Figure 4 A schematic diagram of the current flow direction of the current commutated to the current transfer branch when a fault current occurs provided by the present invention; Figure 5 A schematic diagram of the flow direction of the forward oscillating current when a fault current occurs provided by the present invention; Figure 6 A schematic diagram of the flow direction of the reverse oscillating current when a fault current occurs provided by the present invention; Figure 7 A schematic diagram of the current flow during the fault current release process when a fault occurs provided by the present invention; Figure 8 A schematic structural diagram of an embodiment of a hybrid DC circuit breaker with a bidirectional breaking function provided by the present invention; Figure 9 This is a flow chart of an embodiment of a control method for a hybrid DC circuit breaker provided by the present invention. DETAILED DESCRIPTION
[0018] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.
[0019] It should be understood that the schematic drawings are not drawn to scale. The flowcharts used in the present invention illustrate operations implemented according to some embodiments of the present invention. It should be understood that the operations of the flowcharts can be implemented out of sequence, and steps that have no logical contextual relationship can be reversed in order or implemented simultaneously. In addition, those skilled in the art, guided by the content of the present invention, can add one or more other operations to the flowcharts or remove one or more operations from the flowcharts. Some of the block diagrams shown in the accompanying drawings are functional entities and do not necessarily correspond to physically or logically independent entities. These functional entities can be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and / or processor systems and / or microcontroller systems.
[0020] References herein to "embodiments" mean that a particular feature, structure, or characteristic described in connection with the embodiments may be included in at least one embodiment of the present invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor does it constitute a separate or alternative embodiment that is mutually exclusive of other embodiments. It is understood, both explicitly and implicitly, by those skilled in the art that the embodiments described herein may be combined with other embodiments.
[0021] The present invention provides a hybrid DC circuit breaker and a control method thereof, which are described below.
[0022] Figure 1 This is a schematic structural diagram of an embodiment of a hybrid DC circuit breaker provided by the present invention, as shown in FIG. Figure 1 As shown, the hybrid DC circuit breaker 10 includes: a main current branch 100, a current transfer branch 200, and a regulating branch 300 connected in parallel; the main current branch 100 includes a mechanical switch 110 and a first IGBT 120 connected in series; the current transfer branch 200 includes a second IGBT 210; the regulating branch 300 includes a first diode 310 and a regulating capacitor 320 connected in parallel with the first IGBT 120, and an anti-parallel thyristor 330, one end of the anti-parallel thyristor 330 is connected to the input end of the mechanical switch 110, and the other end of the anti-parallel thyristor 330 is connected between the first diode 310 and the regulating capacitor 320; the anti-parallel thyristor 330 includes a first thyristor 331 and a second thyristor 332 connected in anti-parallel with the first thyristor 331; When a fault current occurs, a first turn-off instruction generated by the host computer to instruct the first IGBT 120 to turn off, a turn-off instruction to instruct the mechanical switch 110 to disconnect, and a first turn-on instruction to instruct the second IGBT 210 to turn on are received. The turn-off instruction and the first turn-on instruction are generated after the first IGBT is turned off. The first IGBT 120 is turned off in response to the first turn-off instruction, the mechanical switch 110 is turned off in response to the disconnection instruction, and the second IGBT 210 is turned on in response to the second turn-on instruction; After the second IGBT 210 is turned on for a preset time, it receives a second turn-on instruction generated by the host computer to instruct the first thyristor 331 and the second thyristor 332 to be turned on simultaneously. The first thyristor 331 and the second thyristor 332 are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch 200. The host computer receives a second shutdown instruction generated when a reverse oscillation current is formed in the current transfer branch 200 to instruct the second IGBT 210 to turn off. The second IGBT 210 turns off in response to the second shutdown instruction.
[0023] It should be noted that the disconnection instruction and the first on-instruction can be generated within a preset time after the first IGBT 120 is turned off. The preset time can be set according to actual application scenarios or experience values and is not specifically limited here.
[0024] It should also be noted that hybrid DC circuit breakers are primarily used to disconnect or protect DC circuits. Their application scenarios cover a wide range of fields. The following are specific application scenarios and examples: 1. In high-voltage direct current (HVDC) transmission systems, hybrid DC circuit breakers can quickly interrupt current flow in the event of a fault, protecting equipment and grid stability. 2. In DC microgrid systems, hybrid DC circuit breakers are used to manage the grid connection and fault isolation of distributed power sources (PV, energy storage). 3. In photovoltaic power generation systems, hybrid DC circuit breakers protect PV arrays, the DC side of inverters, and energy storage batteries from overloads and short circuits. 4. In high-voltage electric vehicle systems, hybrid DC circuit breakers are used to prevent accidents caused by battery short circuits or thermal runaway.
[0025] It should be further explained that the hybrid DC circuit breaker 10 in the embodiment of the present invention is a unidirectional breaking device. Figure 1 As shown, point A is connected to a high potential as the input terminal, and point B is connected to a low potential as the output terminal.
[0026] When there is no fault current, Figure 2 As shown, the first IGBT120 of the main current branch 100 is turned on and the second IGBT210 is turned off, so the current flows in Figure 2 As shown by the double-dotted dashed line in FIG, current flows into port A, passes through mechanical switch 110 and first IGBT 120 of main current branch 100, and flows out of port B. At this time, the voltage clamping technology of first IGBT 120 prevents voltage accumulation in regulation capacitor 320, resulting in no current flowing in regulation branch 300 and no current flowing in current transfer branch 200.
[0027] When a fault current occurs, Figure 3 As shown, the host computer receives the instruction, specifically: the first IGBT120 responds to the first shutdown instruction and turns off, then the current flows to Figure 3 As shown by the double-dotted line in FIG, the main current changes from the first IGBT 120 to the regulating branch 300, thereby charging the regulating capacitor 320. Since the fault current is relatively large, the regulating capacitor 320 can be quickly charged to an extremely high voltage, thereby alleviating the rising speed of the fault current and facilitating subsequent commutation and shutdown operations.
[0028] The subsequent commutation process is as follows Figure 4 As shown, the mechanical switch 110 is disconnected (opened), and the second conduction instruction 210 of the current transfer branch 200 is turned on. Under the superposition of the voltage of the regulating capacitor 320 and the arcing voltage of the mechanical switch 110, the current can be transferred to the current transfer branch 200 more quickly, and the current flow direction is Figure 4 As shown by the double-dotted line in FIG, the regulating capacitor voltage 320 bears part of the commutation pressure, the arc damage suffered by the mechanical switch 110 is weakened, and the opening reliability of the mechanical switch 110 is effectively improved.
[0029] Since the current commutated to the current transfer branch 200 is still relatively large, if the second IGBT 210 is directly turned off, the second IGBT 210 will be subjected to extremely high voltage and current, which may cause the second IGBT 210 to be unable to turn off, resulting in commutation failure and causing serious impact on the circuit system. Therefore, the present invention provides an anti-parallel thyristor 330, Figure 5 The forward oscillating current is formed, that is, the oscillating current ( Figure 5 The dashed line in the figure) and the fault current ( Figure 5 The double-dotted line in the middle) is in the same direction, Figure 6 is the reverse oscillating current of the stroke, that is: oscillating current ( Figure 6 The dotted line in the figure) and the fault flow direction ( Figure 6 When a reverse current forms in the current transfer branch, it exceeds the fault current increase, reducing the current flowing through the second IGBT. At this point, the second IGBT is turned off, preventing the second IGBT from failing to turn off due to excessive current, making the second IGBT's turn-off more stable and reliable.
[0030] It should be noted that, since the insulation recovery of the mechanical switch 110 takes a certain amount of time, the present invention generates a second turn-on instruction instructing the first thyristor 331 and the second thyristor 332 to be turned on at the same time after the second IGBT 210 is turned on for a preset period of time, thereby providing time for the insulation recovery of the mechanical switch 110 and ensuring that the mechanical switch 110 is completely disconnected and the current in the main current branch 100 becomes zero.
[0031] In a specific embodiment of the present invention, the preset time length is 100 μs to 200 μs.
[0032] Compared to the prior art, the hybrid DC circuit breaker 10 provided in the embodiment of the present invention utilizes a regulating branch 300 including a regulating capacitor 320. When a fault current occurs, the regulating capacitor 320 can accumulate a certain amount of energy to regulate the voltage change in the current transfer branch 200 during the shutdown process of the mechanical switch 110. Specifically, the regulating capacitor 320 provides a forward voltage drop during the commutation process from the mechanical switch 110 to the current transfer branch 200, reducing arcing pressure on the mechanical switch 110, accelerating the commutation process, and ensuring the safety of the hybrid DC circuit breaker 10 during commutation. Furthermore, in the embodiment of the present invention, by providing a first thyristor 331 and a second thyristor 332 that conduct in response to a second conduction command, the regulating capacitor 320 and the current transfer branch 200 form a forward and reverse current loop. The regulating capacitor 320 interacts with the stray inductance within the current transfer branch 200 to generate an oscillating current that flows in the current transfer branch 200 in the same or opposite direction as the fault current. When a reverse current is formed in the current transfer branch 200, it is greater than the increase in the fault current, and the current flowing through the second IGBT210 is reduced. At this time, the second IGBT210 is turned off to avoid failure of the second IGBT210 to turn off due to excessive current. This method can make the shutdown of the second IGBT210 more stable and reliable.
[0033] Furthermore, the embodiment of the present invention can limit the current flow direction by providing the first diode 310 , ensuring that the regulating capacitor 320 can only be charged in the forward direction of the current, thereby ensuring the regulating function of the regulating capacitor 320 .
[0034] In actual engineering, commutating the fault current from the main current branch 100 to the current transfer branch 200 only completes one stage of commutation. It is also necessary to release the fault current in the current transfer branch 200. To achieve this goal, in some embodiments of the present invention, such as Figure 1-3 As shown, the combined DC circuit breaker 10 further includes an energy dissipation branch 400 connected in parallel with the main current branch 100. When the second IGBT 210 is turned off, the fault current is released through the energy dissipation branch 400, completing the fault current removal.
[0035] In the embodiment of the present invention, the energy dissipation branch 400 is provided to release the fault current in the current transfer branch 200 and to complete the removal of the fault current.
[0036] In a specific embodiment of the present invention, the energy dissipation branch 400 includes a lightning arrester 410 .
[0037] Based on this setting, the fault current release process is as follows Figure 7As shown, it can be seen from the double-dotted line representing the current flow direction that the fault current is transferred to the energy dissipation branch 400, and the excess energy of the regulating capacitor 320 and the system are released through the energy dissipation branch 400 to complete the fault current removal.
[0038] The hybrid DC circuit breaker proposed in the above embodiment is unidirectional, that is, it can only realize Figure 1 With the increase of the complexity of application scenarios, a hybrid DC circuit breaker capable of realizing bidirectional circuit breaker control is needed. In some embodiments of the present invention, for example, Figure 8 As shown, the main current branch 100 further includes a second diode 130 connected in series with the first IGBT 120, and a third IGBT 140 and a third diode 150 connected in parallel with the first IGBT 120. The current transfer branch 200 further includes a fourth diode 220 connected in series with the second IGBT 210, and a fourth IGBT 230 and a fifth diode 240 connected in parallel with the second IGBT 210. The regulating branch 300 further includes a sixth diode 340 connected in parallel with the first diode 310. The second diode 130 and the third diode 150 are in reverse direction, the first diode 310 and the sixth diode 340 are in reverse direction, and the fourth diode 220 and the fifth diode 240 are in reverse direction.
[0039] In the embodiment of the present invention, the main current branch 100, the current transfer branch 200, and the regulating branch 300 are respectively provided with two loops in different directions, and multiple diodes are used to limit the current flow direction, thereby achieving bidirectional circuit breaking control of the hybrid DC circuit breaker 10.
[0040] In a specific embodiment of the present invention, the mechanical switch is any one of a vacuum high-speed mechanical switch, an air high-speed mechanical switch and an SF6 switch.
[0041] In a specific embodiment of the present invention, the IGBT (Insulated Gate Bipolar Transistor) can also be replaced by other fully controlled semiconductor devices, including but not limited to any one of an integrated gate-commutated thyristor (IGCT), an injection enhanced gate transistor (IEGT) and a gate turn-off thyristor (GTO).
[0042] In a specific embodiment of the present invention, the arrester 410 is at least one of a metal oxide arrester, a line type metal oxide arrester, a gapless line type metal oxide arrester, a fully insulated composite jacket metal oxide arrester, and a detachable arrester.
[0043] In summary, the hybrid DC circuit breaker provided by the embodiment of the present invention, when a fault current occurs and an action instruction is received from the upper computer, the first IGBT of the main current branch receives the action signal and shuts down, and the main current charges the regulating capacitor and instantly reaches a certain voltage, which can also alleviate the fault current rising rate, facilitating subsequent commutation and shutdown operations. The mechanical switch is then opened and the second IGBT of the current transfer branch is turned on. Under the superposition of the regulating capacitor voltage and the mechanical switch arcing voltage, the current can be transferred to the current transfer branch more quickly, and the damage to the mechanical switch from arcing is reduced. This state is maintained for a short time, the insulation of the mechanical switch is restored, the mechanical switch is completely disconnected, and the current of the main current branch becomes zero. After that, the two anti-parallel thyristors are turned on at the same time, and the regulating capacitor and the current transfer branch form a forward and reverse current loop. The regulating capacitor interacts with the stray inductance inside the loop to generate an oscillating current, which is in the same direction or opposite direction as the fault current in the current transfer branch. When a reverse current forms in the current transfer branch, it exceeds the fault current increase, reducing the current flowing through the second IGBT. At this point, the second IGBT is turned off, preventing failure of the second IGBT to shut down due to excessive current. This method makes the second IGBT's shutdown more stable and reliable. As the second IGBT turns off, the fault current transfers to the energy dissipation branch, where excess energy from the regulating capacitor and the system is released, completing the fault current removal.
[0044] Correspondingly, an embodiment of the present invention further provides a control method for a DC circuit breaker, which is applicable to the hybrid DC circuit breaker in any of the above embodiments, such as Figure 9 As shown, the control method of the DC circuit breaker includes: S901, receiving a fault current occurrence instruction; S902. In response to a fault current occurrence instruction, generate a first turn-off instruction to instruct the first IGBT to turn off, a disconnect instruction to instruct the mechanical switch to disconnect, and a first turn-on instruction to instruct the second IGBT to turn on, wherein the disconnect instruction and the first turn-on instruction are generated after the first IGBT is turned off; S903: After the second IGBT is turned on for a preset time, a second turn-on instruction generated by the host computer is received to instruct the first thyristor and the second thyristor to be turned on simultaneously. The first thyristor and the second thyristor are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch. S904 : Receive a second shutdown instruction generated by the host computer when a reverse oscillation current is formed in the current transfer branch, instructing the second IGBT to shut down. The second IGBT shuts down in response to the second shutdown instruction.
[0045] It should be noted that the control method of the DC circuit breaker provided in the above embodiment can implement the technical solution of any commutation stage described in the above DC circuit breaker embodiment. The principles, specific implementation details or completion of the commutation process of each of the above steps can be referred to the corresponding content in the above DC circuit breaker embodiment. For example, the overall commutation process after adding the anti-parallel thyristor and the energy dissipation branch will not be described in detail here.
[0046] Those skilled in the art will appreciate that all or part of the process flow of the above-described method embodiment can be implemented by instructing related hardware (such as a processor, controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium. The computer-readable storage medium may be a magnetic disk, an optical disk, a read-only memory, or a random access memory.
[0047] The hybrid DC circuit breaker and control method thereof provided by the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only intended to help understand the method and core concept of the present invention. At the same time, for those skilled in the art, according to the concept of the present invention, there may be changes in the specific implementation methods and application scopes. In summary, the contents of this specification should not be understood as limiting the present invention.
Claims
1. A hybrid DC circuit breaker, characterized in that: include: A main current branch, a current transfer branch, and a regulating branch connected in parallel; the main current branch includes a mechanical switch and a first IGBT connected in series; the current transfer branch includes a second IGBT; the regulating branch includes an anti-parallel thyristor, a first diode connected in parallel with the first IGBT, and a regulating capacitor; one end of the anti-parallel thyristor is connected to the input end of the mechanical switch, and the other end of the anti-parallel thyristor is connected between the first diode and the regulating capacitor; the anti-parallel thyristor includes a first thyristor and a second thyristor connected in anti-parallel with the first thyristor; When a fault current occurs, receiving a first turn-off instruction generated by a host computer to instruct the first IGBT to turn off, a disconnection instruction to instruct the mechanical switch to disconnect, and a first turn-on instruction to instruct the second IGBT to turn on, wherein the disconnection instruction and the first turn-on instruction are generated after the first IGBT is turned off; The first IGBT is turned off in response to the first turn-off instruction, the mechanical switch is turned off in response to the disconnection instruction, and the second IGBT is turned on in response to the second turn-on instruction; After the second IGBT is turned on for a preset time, a second turn-on instruction generated by the host computer is received to instruct the first thyristor and the second thyristor to be turned on simultaneously, and the first thyristor and the second thyristor are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch; A second shutdown instruction instructing the second IGBT to shut down is received from the host computer when a reverse oscillation current is formed in the current transfer branch, and the second IGBT is shut down in response to the second shutdown instruction.
2. The hybrid DC circuit breaker according to claim 1, characterized in that: The hybrid DC circuit breaker further includes an energy dissipation branch connected in parallel with the main current branch. When the second IGBT is turned off, the fault current is released through the energy dissipation branch, thereby completing fault current removal.
3. The hybrid DC circuit breaker according to claim 2, characterized in that: The energy dissipation branch includes a lightning arrester.
4. The hybrid DC circuit breaker according to claim 1, characterized in that: The preset time length is 100μs~200μs.
5. The hybrid DC circuit breaker according to claim 1, characterized in that: The main current branch further includes a second diode connected in series with the first IGBT, and a third IGBT and a third diode connected in parallel with the first IGBT; the current transfer branch further includes a fourth diode connected in series with the second IGBT, and a fourth IGBT and a fifth diode connected in parallel with the second IGBT; the regulating branch further includes a sixth diode connected in parallel with the first diode; The second diode and the third diode are in reverse direction, the first diode and the sixth diode are in reverse direction, and the fourth diode and the fifth diode are in reverse direction.
6. The hybrid DC circuit breaker according to any one of claims 1 to 5, characterized in that: The mechanical switch is any one of a vacuum high-speed mechanical switch, an air high-speed mechanical switch and an SF6 switch.
7. The hybrid DC circuit breaker according to claim 3, characterized in that: The arrester is at least one of a metal oxide arrester, a line type metal oxide arrester, a gapless line type metal oxide arrester, a fully insulated composite jacket metal oxide arrester, and a detachable arrester.
8. A control method for a DC circuit breaker, characterized in that: Applicable to the hybrid DC circuit breaker according to any one of claims 1 to 7, the control method includes: Receiving a fault current occurrence instruction; In response to the fault current occurrence instruction, generating a first turn-off instruction instructing the first IGBT to turn off, an off instruction instructing the mechanical switch to open, and a first on instruction instructing the second IGBT to turn on, wherein the off instruction and the first on instruction are generated after the first IGBT is turned off; After the second IGBT is turned on for a preset time, a second turn-on instruction generated by the host computer is received to instruct the first thyristor and the second thyristor to be turned on simultaneously, and the first thyristor and the second thyristor are turned on in response to the second turn-on instruction, forming a forward oscillating current and a reverse oscillating current in the current transfer branch; A second shutdown instruction instructing the second IGBT to shut down is received from the host computer when a reverse oscillation current is formed in the current transfer branch, and the second IGBT is shut down in response to the second shutdown instruction.