DC circuit breaker

Abstract

The invention provides a direct-current circuit breaker which comprises a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module and an arc counteracting module, the first main switch and the first auxiliary switch are mutually coupled, and the second main switch and the second auxiliary switch are mutually coupled. The first main switch and the second main switch are connected in series in a main loop, the first auxiliary switch, the control module and the second auxiliary switch are connected in series to the third end of the arc counteracting module, the first end of the arc counteracting module is connected with the other end of the first main switch, the second end of the arc counteracting module is connected with the other end of the second main switch, and the first auxiliary switch is a normally-closed switch. The second auxiliary switch is a normally-on switch. The arc counteracting module is connected in a short time when the direct-current circuit breaker is switched on and switched off, current is switched on and switched off, arc delay when the switch is switched off is reduced, non-arc switching-off is achieved, meanwhile, the switching-off speed of the direct-current circuit breaker is increased, and the service life of the direct-current circuit breaker is prolonged.

Description

Technical Field

[0001] The present application relates to the technical field of circuit breakers, and in particular to a direct current circuit breaker. Background Art

[0002] In a DC system, a DC circuit breaker can conduct, carry and disconnect normal loop current within a specified time. Unlike an AC system, a DC system does not have a natural zero crossing point, and the DC line inductance is small, and the fault current rises quickly, so it is difficult to shut off a DC fault. Therefore, how to use a DC circuit breaker to shut off a DC fault has become an urgent problem to be solved.

[0003] Traditional DC circuit breakers are mechanical DC circuit breakers. Mechanical DC circuit breakers shut down DC faults. Mechanical DC circuit breakers usually eliminate fault arcs by stretching the arc, adding arc extinguishing grids, magnetic blowing out the arc, and changing the arc extinguishing medium. This method has low conduction loss and low cost. However, the mechanical DC circuit breaker has a slow breaking speed, which is not conducive to the rapid removal of fault currents. In addition, the erosion of the contacts by the arc affects the service life of the circuit breaker, requiring frequent replacement, which reduces the reliability of the system.

[0004] In addition, with the continuous development of power electronic devices, power electronic devices are more widely used in traditional circuit breakers, and solid-state DC circuit breakers using power electronic devices as breaking elements have appeared accordingly. Compared with mechanical DC circuit breakers, solid-state DC circuit breakers have the advantages of no arc phenomenon and fast shutdown speed. However, in the normal operation of solid-state DC circuit breakers, due to the large internal resistance of the electronic switch device and the continuous current carrying, the loss is large and the heat is serious. Summary of the invention

[0005] The purpose of the present application is to provide a DC circuit breaker to address the deficiencies in the above-mentioned prior art, so as to solve the problems of slow breaking speed, short life, large loss and severe heat generation of the DC circuit breaker in the prior art.

[0006] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0007] In a first aspect, the present application provides a DC circuit breaker, the DC circuit breaker comprising: a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module, and an arc compensation module;

[0008] The first main switch and the first auxiliary switch are coupled to each other, and the second main switch and the second auxiliary switch are coupled to each other;

[0009] One end of the first main switch is connected to the input end of the DC circuit breaker, and the other end of the first main switch is respectively connected to one end of the second main switch and the first end of the arc compensation module;

[0010] The other end of the second main switch is connected to the output end of the DC circuit breaker;

[0011] One end of the first auxiliary switch is connected to the input end of the DC circuit breaker, and the other end of the first auxiliary switch is connected to one end of the control module;

[0012] One end of the second auxiliary switch is connected to the other end of the control module; the other end of the second auxiliary switch is connected to the third end of the arc cancellation module, and the second end of the arc cancellation module is connected to the other end of the second main switch;

[0013] The first auxiliary switch is a normally-off switch, and the second auxiliary switch is a normally-on switch.

[0014] Optionally, the DC circuit breaker further includes: an overvoltage limiting module;

[0015] One end of the overvoltage limiting module is connected to the other end of the first main switch, and the other end of the overvoltage limiting module is connected to the other end of the second main switch.

[0016] Optionally, when the contact of the first main switch is located at a first preset position, the first main switch is disconnected and the first auxiliary switch is disconnected;

[0017] When the contact of the first main switch is located at a second preset position, the first main switch is disconnected and the first auxiliary switch is turned on;

[0018] When the contact of the first main switch is located at a third preset position, the first main switch is turned on and the first auxiliary switch is turned on;

[0019] Among them, the distance between the second preset position and the initial position of the contact of the first main switch is greater than the distance between the first preset position and the initial position of the contact of the first main switch, and the distance between the third preset position and the initial position of the contact of the first main switch is greater than the distance between the second preset position and the initial position of the contact of the first main switch.

[0020] Optionally, when the contact of the second main switch is located at a fourth preset position, the second main switch is disconnected and the second auxiliary switch is turned on;

[0022] When the contact of the second main switch is located at a fifth preset position, the second main switch is disconnected and the second auxiliary switch is disconnected;

[0023] When the contact of the second main switch is located at a sixth preset position, the second main switch is turned on and the second auxiliary switch is turned off;

[0024] Among them, the distance between the fifth preset position and the initial position of the contact of the second main switch is greater than the distance between the fourth preset position and the initial position of the contact of the second main switch, and the distance between the sixth preset position and the initial position of the contact of the second main switch is greater than the distance between the fifth preset position and the initial position of the contact of the second main switch.

[0025] Optionally, the arc cancellation module includes at least one junction field effect transistor;

[0026] The first end of each of the junction field effect transistors is respectively connected to the other end of the first main switch;

[0027] The second end of each of the junction field effect transistors is respectively connected to the other end of the second main switch;

[0028] The third end of each of the junction field effect transistors is connected to the other end of the second sub-switch respectively.

[0029] Optionally, the overvoltage limiting module includes: a resistor, a capacitor and a lightning arrester module;

[0030] One end of the resistor is respectively connected to the other end of the first main switch, one end of the second main switch and the first end of the arc cancellation module, the other end of the resistor is connected to one end of the capacitor, and the other end of the capacitor is respectively connected to the other end of the second main switch and the second end of the arc cancellation module;

[0031] One end of the lightning arrester module is connected to one end of the resistor, and the other end of the lightning arrester module is connected to the other end of the capacitor.

[0032] Optionally, the arrester module includes: at least one varistor;

[0033] One end of each varistor is connected to one end of the resistor, and the other end of each varistor is connected to the other end of the capacitor.

[0034] Optionally, the lightning arrester module includes: at least one transient voltage suppressor.

[0035] One end of each of the transient voltage suppressors is connected to one end of the resistor, and the other end of each of the transient voltage suppressors is connected to the other end of the capacitor.

[0036] Optionally, the control module includes: a power taking unit and a driving unit;

[0037] The power supply unit is used to supply power to the driving unit;

[0038] The driving unit is used to input a driving signal to the arc cancellation module when the first auxiliary switch and the second auxiliary switch are turned on.

[0039] In a second aspect, the present application provides a DC system, which includes the DC circuit breaker described in the first aspect.

[0040] The beneficial effects of the present application are as follows: a DC circuit breaker includes: a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module and an arc cancellation module, wherein the first main switch and the first auxiliary switch are coupled to each other, and the second main switch and the second auxiliary switch are coupled to each other, so that when the switch contacts of the first main switch and the second main switch move, the first auxiliary switch and the second auxiliary switch are triggered to be turned on and off. One end of the first main switch is connected to the input end of the DC circuit breaker, and the other end of the first main switch is respectively connected to one end of the second main switch and the first end of the arc cancellation module. The other end of the second main switch is connected to the output end of the DC circuit breaker. One end of the first auxiliary switch is connected to the input end of the DC circuit breaker, and the other end of the first auxiliary switch is connected to one end of the control module. One end of the second auxiliary switch is connected to the other end of the control module. The other end of the second auxiliary switch is connected to the third end of the arc cancellation module, and the second end of the arc cancellation module is connected to the other end of the second main switch. The arc compensation module is used to short-term access and realize the conduction and disconnection of current during the closing and opening process of the DC circuit breaker, reduce the delay caused by the arc when the switch is disconnected, and accelerate the shutdown speed of the DC circuit breaker while achieving arc-free closure, reduce the fault current peak, reduce the erosion of the arc on the contacts, avoid excessive heating, extend the life of the DC circuit breaker, and improve the reliability of the DC system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0042] Figure 1 A schematic diagram showing an application scenario of a DC circuit breaker provided in an embodiment of the present application is shown;

[0043] Figure 2 A schematic structural diagram of a DC circuit breaker provided in an embodiment of the present application is shown;

[0044] Figure 3 A schematic structural diagram of a DC circuit breaker including an overvoltage limiting module provided in an embodiment of the present application is shown;

[0045] Figure 4A schematic diagram of the structure of a first main switch and a first auxiliary switch provided in an embodiment of the present application is shown;

[0046] Figure 5 A schematic diagram of the structure of a second main switch and a second auxiliary switch provided in an embodiment of the present application is shown;

[0047] Figure 6 A schematic structural diagram of an arc compensation module provided in an embodiment of the present application is shown;

[0048] Figure 7 A schematic structural diagram of an overvoltage limiting module provided in an embodiment of the present application is shown;

[0049] Figure 8 A schematic structural diagram of a first lightning arrester module provided in an embodiment of the present application is shown;

[0050] Fig. 9 A schematic structural diagram of a second lightning arrester module provided in an embodiment of the present application is shown;

[0051] Fig.10 A structural schematic diagram of a control module provided in an embodiment of the present application is shown. DETAILED DESCRIPTION

[0052] To make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the drawings in the present application only serve the purpose of explanation and description and are not used to limit the scope of protection of the present application. In addition, it should be understood that the schematic drawings are not drawn in real proportion. The flowchart used in this application shows the operations implemented according to some embodiments of the present application. It should be understood that the operations of the flowchart can be implemented out of sequence, and the steps without logical context can be reversed in order or implemented simultaneously. In addition, those skilled in the art can add one or more other operations to the flowchart under the guidance of the content of the present application, or remove one or more operations from the flowchart.

[0053] In addition, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various configurations. Therefore, the following detailed description of the embodiments of the present application provided in the drawings is not intended to limit the scope of the application claimed for protection, but merely represents the selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present application.

[0054] It should be noted that the term "comprising" will be used in the embodiments of the present application to indicate the existence of the features declared thereafter, but does not exclude the addition of other features.

[0055] Traditional mechanical DC circuit breakers mainly use methods such as lengthening the arc, adding arc extinguishing grids, magnetic blowing out the arc, and changing the arc extinguishing medium to eliminate the fault arc. This method has low on-state loss and low cost, but the circuit breaker has a slow breaking speed, which is not conducive to the rapid removal of fault current. In addition, the erosion of the contacts by the arc affects the service life of the circuit breaker, requiring frequent replacement, which reduces the reliability of the system.

[0056] With the development of power electronic devices, solid-state DC circuit breakers using power electronic devices as breaking elements have emerged. Compared with traditional mechanical circuit breakers, solid-state circuit breakers have the characteristics of no arc phenomenon and fast shutdown speed. However, in normal operation, since the electronic switch device has a large internal resistance and continuously carries current when it is turned on, the loss is large and the heat is serious. In addition, in order to achieve a larger current system, the electronic switch device has higher requirements, resulting in a high price for solid-state circuit breakers.

[0057] Based on the above problems, the present application proposes a DC circuit breaker, which includes a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module and an arc cancellation module. During the closing and opening process of the DC circuit breaker, the arc cancellation module conducts current through the coupling of the first main switch and the first auxiliary switch, and the coupling of the second main switch and the second auxiliary switch, so as to achieve arc-free or micro-arc disconnection. The arc cancellation module has a small on-resistance, so the heat generation is small.

[0058] The DC circuit breaker proposed in this application can be used to control a DC system to achieve conduction, load bearing and disconnection within a specified time. Figure 1 This is an application scenario of a DC circuit breaker. The input and output ends of the DC circuit breaker are respectively connected to the two ends of the DC system.

[0059] Below, refer to Figure 2 The specific structure of the DC circuit breaker 10 is introduced as follows:

[0060] Optionally, the DC circuit breaker 10 includes: a first main switch S1 , a second main switch S2 , a first auxiliary switch S11 , a second auxiliary switch S21 , a control module 101 and an arc compensation module 102 .

[0061] Optionally, the first main switch S1 may be an isolating contact, and the second main switch S2 may be a high-speed mechanical switch. The first auxiliary switch S11 and the second auxiliary switch S21 may be coupling switches or travel switches.

[0062] Optionally, the arc cancellation module 102 may be composed of junction field effect transistors connected in parallel.

[0063] Optionally, the first main switch S1 and the first secondary switch S11 are coupled to each other, and the second main switch S2 and the second secondary switch S21 are coupled to each other.

[0064] Optionally, the first main switch S1 and the second main switch S2 are connected in series in a main circuit, wherein the main circuit may be a main circuit connected to a DC system.

[0065] Optionally, during the closing and opening process of the first main switch S1, the first main switch S1 and the first auxiliary switch S11 can be coupled to each other through mechanical connection or magnetic coupling, so that the first auxiliary switch S11 can be turned on or off when the contact of the first main switch S1 reaches a preset position of the first main switch S1.

[0066] Optionally, during the closing and opening process of the second main switch S2, the second main switch S2 and the second auxiliary switch S21 can be coupled to each other through a mechanical connection or a magnetic coupling, so that the second auxiliary switch S21 can be disconnected or connected when the contact of the second main switch S2 reaches a preset position of the second main switch S2.

[0067] It is worth noting that the coupling mode between the first main switch and the first auxiliary switch, and the coupling mode between the second main switch and the second auxiliary switch are not limited.

[0068] Optionally, since the arc cancellation module 102 cannot be completely isolated and leakage current may exist, when the DC system main circuit is disconnected, the first main switch S1 and the second main switch S2 need to be disconnected at the same time to achieve a safety isolation function.

[0069] Optionally, one end of the first main switch S1 is connected to the input end of the DC circuit breaker, and the other end of the first main switch S1 is respectively connected to one end of the second main switch S2 and the first end of the arc cancellation module 102 .

[0070] Optionally, the other end of the second main switch S2 is connected to an output end of the DC circuit breaker 10 .

[0071] Optionally, one end of the first auxiliary switch S11 is connected to the input end of the DC circuit breaker 10 , and the other end of the first auxiliary switch S11 is connected to one end of the control module 101 .

[0072] Optionally, one end of the second secondary switch S21 is connected to the other end of the control module 101. The other end of the second secondary switch S21 is connected to the third end of the arc cancellation module 102, and the second end of the arc cancellation module 102 is connected to the other end of the second main switch S2.

[0073] Optionally, the first main switch S1 and the second main switch S2 can be closed and opened according to the control signal sent by the control system. It is worth noting that the control system is located in the DC system and can monitor the state of the DC system. If the control system detects that the current of the main circuit in the DC system exceeds a preset short-circuit threshold, it is determined that a short-circuit fault occurs in the DC system. At this time, the control system can control the first main switch S1 and the second main switch S2 in the DC circuit breaker 10 to open.

[0074] Optionally, the first secondary switch S11 is a normally-off switch, and the second secondary switch S21 is a normally-on switch.

[0075] Optionally, the processes of closing, opening and fault status of the DC circuit breaker 10 are respectively introduced below.

[0076] In the process of closing the DC circuit breaker 10, the first main switch S1 is closed first. Specifically, in the process of closing the first main switch S1, the switch contact of the first main switch S1 moves from the initial position to the direction close to the closed position. In the process of moving to the direction close to the closed position, the first auxiliary switch S11 is first triggered to close, so that the control module 101 is powered on. The control module 101 drives the arc cancellation module 102 to open, and the switch contact of the first main switch S1 continues to move in the direction close to the closed position. After a certain mechanical delay, the first main switch S1 starts to turn on, and when the switch contact of the first main switch S1 is completely moved to the closed position, the first main switch S1 is fully turned on.

[0077] Then the second main switch S2 is closed, and during the closing process, the switch contact moves from the initial position toward the direction close to the closed position. In the process of moving toward the closed position, the second auxiliary switch S21 is first triggered to disconnect. At this time, the arc cancellation module 102 is turned on, and the switch contact continues to move toward the closed position. After a certain mechanical delay, the second main switch S2 starts to connect, and the switch contact continues to move toward the closed position until it reaches the closed position. At this time, the second main switch S2 is turned on, and the closing process of the DC circuit breaker 10 is completed.

[0078] During the closing process of the DC circuit breaker 10, before the second main switch S2 starts to be connected, the arc cancellation module 102 is turned on, so the voltage across the second main switch S2 is extremely low, so that the second main switch S2 will not generate an arc during the closing process. When the second main switch S2 is fully turned on, since the on-resistance of the second main switch S2 is extremely low, most of the current in the DC system is switched from the arc cancellation module 102 to the second main switch S2, so the current passing through the arc cancellation module 102 is very small, so that the arc cancellation module 102 will not carry current for a long time, so that the arc cancellation module has a low temperature and a long service life.

[0079] During the opening process of the DC circuit breaker 10, the second main switch S2 is opened first. Specifically, the switch contact of the second main switch S2 moves from the closed position to the direction away from the closed position, and the second main switch S2 begins to open during the movement away from the closed position. The switch contact continues to move in the direction away from the closed position, and after a certain mechanical delay, the second auxiliary switch S21 is turned on, and the arc compensation module 102 is disconnected. The switch contact continues to move in the direction away from the closed position until the initial position, and the second main switch S2 is disconnected, completing the opening of the second main switch S2.

[0080] During the opening process of the second main switch S2, before the second sub-switch S21 is turned on, in the process that the switch contact moves away from the closed position until the second main switch S2 is disconnected, the resistance at the second main switch S2 gradually increases, and the current originally flowing through the second main switch S2 is transferred to the arc cancellation module 102. Since the arc cancellation module 102 is in the on state at this time, the voltage across the second main switch S2 is low and no arc is generated.

[0081] During the opening process of the DC circuit breaker 10, after the opening of the second main switch S2 is completed, the opening of the first main switch S1 is performed. Specifically, the switch contact of the first main switch S1 moves from the closed position to the direction away from the closed position, and the first main switch S1 begins to open in the process of moving in the direction away from the closed position, and the switch contact of the first main switch S1 continues to move in the direction away from the closed position, and the first main switch S1 is completely opened, and the switch contact of the first main switch S1 continues to move in the direction away from the closed position. After a certain mechanical delay, the first auxiliary switch S11 is opened, and at this time, the arc compensation module 102 is turned on, and the switch contact of the first main switch S1 continues to move in the direction away from the closed position to the starting position, and the opening of the first main switch S1 is completed.

[0082] When the control system detects that a short circuit fault occurs in the DC system, the DC circuit breaker 10 is controlled to open.

[0083] Specifically, first, the second main switch S2 is opened. The switch contact of the second main switch S2 moves from the closed position to a direction away from the closed position, and the second main switch S2 begins to open during the movement to a direction away from the closed position, and the arc compensation module 102 is in the on state.

[0084] At this time, the on-resistance at the second main switch S2 increases, and an arc is generated between the switch contacts. Therefore, the current originally flowing through the second main switch S2 is transferred to the branch where the arc cancellation module 102 is located. Since the arc cancellation module 102 is in the on state, the voltage across the second main switch S2 is low. Therefore, even if the current continues to rise, the arc of the second main switch S2 will be extinguished as the switch contacts of the second main switch S2 move away from the closed position.

[0085] The switch contact of the second main switch S2 continues to move away from the closed position, and after a mechanical delay, the second auxiliary switch S21 is closed, and the arc compensation module 102 is disconnected.

[0086] In order to ensure the safety of the DC system, the DC circuit breaker 10 needs to be completely shut down, so the first main switch S1 needs to be turned off. Specifically, the switch contact of the first main switch S1 moves from the closed position to the direction away from the closed position. In the process of the switch contact moving away from the closed position, the first main switch S1 begins to disconnect, and the switch contact continues to move away from the closed position. After a period of mechanical delay, the first main switch S1 is completely disconnected, and the switch contact continues to move away from the closed position. After a period of mechanical delay, the first sub-switch S11 is disconnected, and the arc cancellation module 102 is turned on. The switch contact continues to move in the direction away from the closed position until it moves to the starting position, at which time the first main switch S1 is opened. At this time, the DC circuit breaker 10 is completely opened to ensure the safety of the DC system.

[0087] In this embodiment, the DC circuit breaker includes: a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module and an arc cancellation module. The first main switch and the first auxiliary switch are coupled to each other, and the first main switch and the second auxiliary switch are coupled to each other, so when the switch contacts of the first main switch and the second main switch move, the first auxiliary switch and the second auxiliary switch are triggered to be turned on and off. One end of the first main switch is connected to the input end of the DC circuit breaker, and the other end of the first main switch is respectively connected to one end of the second main switch and the first end of the arc cancellation module. The other end of the second main switch is connected to the output end of the DC circuit breaker. One end of the first auxiliary switch is connected to the input end of the DC circuit breaker, and the other end of the first auxiliary switch is connected to one end of the control module. One end of the second auxiliary switch is connected to the other end of the control module. The other end of the second auxiliary switch is connected to the third end of the arc cancellation module, and the second end of the arc cancellation module is connected to the other end of the second main switch. This embodiment utilizes the arc compensation module to be briefly connected during the closing and opening process of the DC circuit breaker to realize the conduction and disconnection of the current, thereby reducing the delay generated by the arc when the switch is disconnected, accelerating the shutdown speed of the DC circuit breaker while realizing arc-free closure, reducing the fault current peak, reducing the erosion of the arc on the contacts, avoiding excessive heating, extending the life of the DC circuit breaker, and improving the reliability of the DC system.

[0088] Next, refer to Figure 3 The structure of the overvoltage limiting module 103 also included in the DC circuit breaker 10 is introduced.

[0089] Optionally, one end of the overvoltage limiting module 103 is connected to the other end of the first main switch S1 , and the other end of the overvoltage limiting module 103 is connected to the other end of the second main switch S2 .

[0090] Optionally, the overvoltage limiting module 103 is used to protect the arc compensation module 102 to prevent overvoltage damage to the arc compensation module 102. Specifically, during the opening process of the DC circuit breaker 10, when the second main switch S2 begins to disconnect, the switch contact resistance increases, and the current is transferred to the arc compensation module 102. After a certain mechanical delay, the second auxiliary switch S21 is turned on, and the arc compensation module 102 is disconnected. At this time, the current is transferred to the branch where the overvoltage limiting module 103 is located, and the overvoltage limiting module 103 completes the shutdown energy dissipation.

[0091] Optionally, when the voltage exceeds the voltage threshold of the overvoltage limiting module 103, the overvoltage limiting module 103 dissipates energy until the voltage on both sides of the overvoltage limiting module 103 is lower than the voltage threshold, thereby protecting the arc compensation module 102. The voltage threshold can be determined by the characteristics of the overvoltage limiting module 103.

[0092] In this embodiment, the arc compensation module is protected by the overvoltage limiting module, thereby extending the service life of the DC circuit breaker.

[0093] Next, refer to Figure 4 The structures of the first main switch S1 and the first auxiliary switch S11 in the DC circuit breaker 10 are introduced.

[0094] Optionally, when the contact of the first main switch S1 is located at the first preset position, the first main switch S1 is disconnected and the first auxiliary switch S11 is disconnected.

[0095] Optionally, when the contact of the first main switch S1 is located at the second preset position, the first main switch S1 is disconnected and the first auxiliary switch S11 is turned on.

[0096] Optionally, when the contact of the first main switch S1 is located at the third preset position, the first main switch S1 is turned on and the first auxiliary switch S11 is turned on.

[0097] Optionally, the distance between the second preset position and the initial position of the contact of the first main switch S1 is greater than the distance between the first preset position and the initial position of the contact of the first main switch S1, and the distance between the third preset position and the initial position of the contact of the first main switch S1 is greater than the distance between the second preset position and the initial position of the contact of the first main switch S1.

[0098] Optionally, in the first main switch S1, when the moving contact moves to the stationary contact, the current switch state is closed, the contact position is closed, and the current switch is in a fully conductive state. When the moving contact is away from the stationary contact, the current switch is not in a closed state, and when the moving contact is in the starting position, the current switch is in a fully disconnected state.

[0099] Optionally, during the closing process of the first main switch S1, when the switch contact of the first main switch S1 moves to a second preset position in a direction close to the closed position, the first secondary switch S11 is turned on, and when the switch contact of the first main switch S1 continues to move to a third preset position in a direction close to the closed position, the first main switch S1 starts to turn on, and when the switch contact moves to the closed position in a direction close to the closed position, the first main switch S1 is fully turned on.

[0100] Optionally, during the opening process of the first main switch S1, when the switch contact of the first main switch S1 moves in a direction away from the closed position to a second preset position, the second main switch S2 starts to open, and the switch contact continues to move in a direction away from the closed position. When the first preset position is reached, the first secondary switch S11 opens, and when the switch contact continues to move in a direction away from the closed position to the starting position, the first main switch S1 is completely opened to achieve opening.

[0101] In this embodiment, the first main switch contacts move to corresponding positions to trigger the first auxiliary switch to turn on or off, thereby controlling the on and off of the arc cancellation module, and then conducting current during the DC circuit breaker closing process to achieve arc-free closure and extend the life of the DC circuit breaker.

[0102] Next, refer to Figure 5 The structures of the second main switch S2 and the second auxiliary switch S21 in the DC circuit breaker 10 are introduced.

[0103] Optionally, when the contact of the second main switch S2 is located at the fourth preset position, the second main switch S2 is disconnected and the second auxiliary switch S21 is turned on.

[0104] Optionally, when the contact of the second main switch S2 is located at the fifth preset position, the second main switch S2 is disconnected and the second auxiliary switch S21 is disconnected.

[0105] Optionally, when the contact of the second main switch S2 is located at the sixth preset position, the second main switch S2 is turned on and the second auxiliary switch S21 is turned off.

[0106] Optionally, the distance between the fifth preset position and the initial position of the contact of the second main switch S2 is greater than the distance between the fourth preset position and the initial position of the contact of the second main switch S2, and the distance between the sixth preset position and the initial position of the contact of the second main switch S2 is greater than the distance between the fifth preset position and the initial position of the contact of the second main switch S2.

[0107] Optionally, in the second main switch S2, when the moving contact moves to the stationary contact, the current switch state is the closed state, the contact position is the closed position, and the current switch is in a fully conductive state. When the moving contact is away from the stationary contact, the current switch is not in a closed state, and when the moving contact is in the starting position, the current switch is in a fully disconnected state.

[0108] Optionally, during the closing process of the second main switch S2, when the switch contact of the second main switch S2 moves to a fifth preset position in a direction close to the closed position, the second secondary switch S21 is disconnected, and when the switch contact of the second main switch S2 continues to move to a sixth preset position in a direction close to the closed position, the second main switch S2 starts to conduct, and when the switch contact moves to the closed position in a direction close to the closed position, the second main switch S2 is fully conducted.

[0109] Optionally, during the opening process of the second main switch S2, when the switch contact of the second main switch S2 moves to a fifth preset position in a direction away from the closed position, the second main switch S2 begins to open, and the switch contact continues to move in a direction away from the closed position. When the first auxiliary switch S11 reaches the fourth preset position, and when the switch contact continues to move to the starting position in a direction away from the closed position, the first main switch S1 is completely opened to achieve opening.

[0110] It is worth noting that in the second main switch S2, the distance from the closed position to the fourth preset position is greater than the opening distance threshold, so as to ensure that during the opening process, the dielectric insulation between the contacts of the second main switch S2 is restored to a level sufficient to withstand the system overvoltage, and to ensure that when the arc compensation module 102 is disconnected, the voltage increase across the second main switch S2 is not sufficient to cause the moving and static contacts to re-ignite the arc. The opening distance threshold can be preset by the user according to the material of the switch contact and the gas medium in which the switch is located.

[0111] In this embodiment, the second main switch contacts move to corresponding positions to trigger the second auxiliary switch to turn on or off, thereby controlling the on and off of the arc cancellation module, and then conducting current during the DC circuit breaker closing process to achieve arc-free closure and extend the life of the DC circuit breaker.

[0112] Next, refer to Figure 6 The structure of the arc cancellation module 102 is introduced.

[0113] Optionally, the arc cancellation module 102 includes at least one junction field effect transistor.

[0114] Optionally, the first end of each junction field effect transistor is respectively connected to the other end of the first main switch S1.

[0115] Optionally, the second end of each junction field effect transistor is respectively connected to the other end of the second main switch S2.

[0116] Optionally, the third end of each junction field effect transistor is respectively connected to the other end of the second sub-switch S21.

[0117] Optionally, a Junction Field-Effect Transistor (JFET) has the characteristics of high impedance, small size, long life and high efficiency.

[0118] Optionally, when the first sub-switch S11 and the second sub-switch S21 are turned on, the control module 101 is powered on, and the control module 101 drives the JFET to be turned on and off, thereby canceling the arc.

[0119] Optionally, the more JFETs are included in the arc cancellation module 102, the higher the arc cancellation efficiency and the better the effect, but the size of the DC circuit breaker 10 increases and the cost increases.

[0120] Optionally, since the resistance of the first main switch S1 and the second main switch S2 is much smaller than the resistance of the JFET when they are turned on, the JFET will not be overheated when the main circuit of the DC system is turned on, thereby extending the service life.

[0121] In this embodiment, the arc compensation module includes at least one junction field effect transistor, thereby ensuring that there is no arc and improving the shutdown efficiency of the DC circuit breaker.

[0122] Next, refer to Figure 7 The specific structure of the overvoltage limiting module 103 is introduced.

[0123] Optionally, the overvoltage limiting module 103 includes: a resistor R, a capacitor C and a lightning arrester module 1031 .

[0124] Optionally, one end of the resistor R is respectively connected to the other end of the first main switch S1, one end of the second main switch S2 and the first end of the arc cancellation module 102, the other end of the resistor R is connected to one end of the capacitor C, and the other end of the capacitor C is respectively connected to the other end of the second main switch S2 and the second end of the arc cancellation module 102.

[0125] Optionally, one end of the lightning arrester module 1031 is connected to one end of the resistor R, and the other end of the lightning arrester module 1031 is connected to the other end of the capacitor C.

[0126] Optionally, when a short circuit occurs in the DC system, the second main switch S2 begins to open, and during the movement of the switch contact from the closed position to the direction away from the closed position, the second main switch S2 begins to disconnect, and the current is transferred to the branch where the arc compensation module 102 is located. During the mechanical delay process, the arc suppression module bears the short-circuit current, and the short-circuit current continues to rise, the switch contact continues to move in the direction away from the closed position, the second sub-switch S21 is turned on, and the arc compensation module 102 is turned off. At this time, the current is transferred to the overvoltage limiting module 103, and the overvoltage limiting module 103 dissipates the residual energy of the main circuit. Specifically, the current passes through the resistor R and the capacitor C connected in series, so that the voltage at both ends of the branch where the resistor R and the capacitor C are located increases rapidly until it is greater than or equal to the system voltage and reaches the maximum value. When the voltage at both ends of the branch is greater than the voltage threshold of the arrester module 1031, the arrester module 1031 quickly changes from a high-resistance state to a low-resistance state, discharges the residual electric energy when the main circuit is shut down, and converts it into heat energy, while clamping the overvoltage within a safe range. When the remaining energy of the main circuit is completely dissipated by the arrester module 1031, the arrester module 1031 returns to a high-resistance state, and the branch where the overvoltage limiting module 103 is located is disconnected, thereby achieving energy dissipation of the main circuit, thereby protecting the DC system from safety when a short circuit fault occurs in the DC system.

[0127] Optionally, the resistor R and the capacitor C are connected in series and in parallel with the arc compensation module 102, which can limit the rapid increase of the voltage at both ends of the branch where the arc compensation module 102 is located.

[0128] Optionally, the resistor R and the capacitor C are connected in series and in parallel with the lightning arrester module 1031, and can be clamped with the lightning arrester to prevent the arc compensation module 102 from being damaged by overvoltage.

[0129] In this embodiment, the resistor, capacitor and lightning arrester module included in the overvoltage limiting module can limit the rapid increase of voltage at both ends of the branch where the arc compensation module is located, and avoid overvoltage damage to the arc compensation module.

[0130] As an optional implementation, refer to Figure 8 The structure of the lightning arrester module 1031 is introduced.

[0131] Optionally, the lightning arrester module 1031 includes: at least one varistor.

[0132] Optionally, one end of each varistor is connected to one end of the resistor R, and the other end of each varistor is connected to the other end of the capacitor C, respectively.

[0133] Optionally, the varistor may be a metal oxide varistor.

[0134] Optionally, the resistance of a varistor (Metal Oxide Varistors, MOV) can vary according to the voltage applied thereto, thereby achieving overvoltage protection.

[0135] In this embodiment, overvoltage protection of the arc compensation module is achieved by a varistor.

[0136] As another optional implementation, refer to Fig. 9 Another structure of the lightning arrester module 1031 is introduced.

[0137] Optionally, the lightning arrester module 1031 includes: at least one transient voltage suppressor.

[0138] Optionally, one end of each transient voltage suppressor is connected to one end of the resistor R, and the other end of each transient voltage suppressor is connected to the other end of the capacitor C, respectively.

[0139] Optionally, a transient voltage suppressor (TVS) can dissipate energy above a voltage threshold in the main circuit, thereby achieving overvoltage protection.

[0140] In this embodiment, overvoltage protection of the arc compensation module is achieved by a transient voltage suppressor.

[0141] Next, refer to Fig.10 The structure of the control module 101 is introduced.

[0142] Optionally, the control module 101 includes: a power supply unit 1011 and a driving unit 1012 .

[0143] Optionally, the power supply unit 1011 is used to supply power to the driving unit 1012 .

[0144] Optionally, the driving unit 1012 is used to input a driving signal to the arc cancellation module 102 when the first auxiliary switch S11 and the second auxiliary switch S21 are turned on.

[0145] Optionally, when the first sub-switch S11 and the second sub-switch S21 are turned on, the driving unit 1012 in the control module 101 sends a driving signal to the arc cancellation module 102 to turn it off. When either the first sub-switch S11 or the second sub-switch S21 is disconnected, the power supply unit 1011 in the control module 101 cannot supply power to the driving unit 1012, and the driving unit 1012 stops sending the driving signal to the arc cancellation module 102, and the arc cancellation module 102 is turned on.

[0146] In this embodiment, a driving signal is sent to the arc cancellation module by a driving unit in the control module to control its on and off.

[0147] An embodiment of the present application further provides a DC system, which includes the DC circuit breaker described above.

[0148] The above are only specific implementation methods of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be covered by the protection scope of the present application.

Claims

1. A DC circuit breaker, characterized in that: The DC circuit breaker comprises: a first main switch, a second main switch, a first auxiliary switch, a second auxiliary switch, a control module and an arc compensation module; The first main switch and the first auxiliary switch are coupled to each other, and the second main switch and the second auxiliary switch are coupled to each other; One end of the first main switch is connected to the input end of the DC circuit breaker, and the other end of the first main switch is respectively connected to one end of the second main switch and the first end of the arc compensation module; The other end of the second main switch is connected to the output end of the DC circuit breaker; One end of the first auxiliary switch is connected to the input end of the DC circuit breaker, and the other end of the first auxiliary switch is connected to one end of the control module; One end of the second auxiliary switch is connected to the other end of the control module; the other end of the second auxiliary switch is connected to the third end of the arc cancellation module, and the second end of the arc cancellation module is connected to the other end of the second main switch; The first auxiliary switch is a normally-off switch, and the second auxiliary switch is a normally-on switch.

2. The DC circuit breaker according to claim 1, characterized in that: The DC circuit breaker further includes: an overvoltage limiting module; One end of the overvoltage limiting module is connected to the other end of the first main switch, and the other end of the overvoltage limiting module is connected to the other end of the second main switch.

3. The DC circuit breaker according to claim 1 or 2, characterized in that: When the contact of the first main switch is located at a first preset position, the first main switch is disconnected and the first auxiliary switch is disconnected; When the contact of the first main switch is located at a second preset position, the first main switch is disconnected and the first auxiliary switch is turned on; When the contact of the first main switch is located at a third preset position, the first main switch is turned on and the first auxiliary switch is turned on; Among them, the distance between the second preset position and the initial position of the contact of the first main switch is greater than the distance between the first preset position and the initial position of the contact of the first main switch, and the distance between the third preset position and the initial position of the contact of the first main switch is greater than the distance between the second preset position and the initial position of the contact of the first main switch.

4. The DC circuit breaker according to claim 1 or 2, characterized in that: When the contact of the second main switch is at a fourth preset position, the second main switch is disconnected and the second auxiliary switch is turned on; When the contact of the second main switch is located at a fifth preset position, the second main switch is disconnected and the second auxiliary switch is disconnected; When the contact of the second main switch is located at a sixth preset position, the second main switch is turned on and the second auxiliary switch is turned off; Among them, the distance between the fifth preset position and the initial position of the contact of the second main switch is greater than the distance between the fourth preset position and the initial position of the contact of the second main switch, and the distance between the sixth preset position and the initial position of the contact of the second main switch is greater than the distance between the fifth preset position and the initial position of the contact of the second main switch.

5. The DC circuit breaker according to claim 1, characterized in that: The arc cancellation module includes at least one junction field effect transistor; The first end of each of the junction field effect transistors is respectively connected to the other end of the first main switch; The second end of each of the junction field effect transistors is respectively connected to the other end of the second main switch; The third end of each of the junction field effect transistors is connected to the other end of the second sub-switch respectively.

6. The DC circuit breaker according to claim 2, characterized in that: The overvoltage limiting module includes: a resistor, a capacitor and a lightning arrester module; One end of the resistor is respectively connected to the other end of the first main switch, one end of the second main switch and the first end of the arc cancellation module, the other end of the resistor is connected to one end of the capacitor, and the other end of the capacitor is respectively connected to the other end of the second main switch and the second end of the arc cancellation module; One end of the lightning arrester module is connected to one end of the resistor, and the other end of the lightning arrester module is connected to the other end of the capacitor.

7. The DC circuit breaker according to claim 6, characterized in that: The arrester module comprising: at least one varistor; One end of each varistor is connected to one end of the resistor, and the other end of each varistor is connected to the other end of the capacitor.

8. The DC circuit breaker according to claim 6, characterized in that: The arrester module includes: at least one transient voltage suppressor; One end of each of the transient voltage suppressors is connected to one end of the resistor, and the other end of each of the transient voltage suppressors is connected to the other end of the capacitor.

9. The DC circuit breaker according to claim 1, characterized in that: The control module includes: a power taking unit and a driving unit; The power supply unit is used to supply power to the driving unit; The driving unit is used to input a driving signal to the arc cancellation module when the first auxiliary switch and the second auxiliary switch are turned on.

10. A DC system, characterized in that: The DC system comprises the DC circuit breaker according to any one of claims 1-9.

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