Circuit breakers and their control methods

Abstract

This invention discloses a circuit breaker, comprising a moving contact 1, a moving contact spring 2, a connecting rod 3, a moving contact spring 4, a moving contact 5, a stationary contact 6, a stationary contact 7, a stationary contact 8, and a stationary contact 9. The circuit breaker is characterized by: a height difference h between the bottom surfaces of moving contact 1 and moving contact 5; and an arc-extinguishing circuit between the moving and stationary contacts and another parallel moving and stationary contact with the same structure. Through this design, switches J1 and J2 can be sequentially opened and closed. Combined with the arc-extinguishing circuit, energy is recovered without loss in the circuit, providing excellent arc-extinguishing performance, ensuring physical isolation in the circuit, and increasing the product's service life.

Description

Technical Field

[0001] This invention relates to circuit breakers, and more particularly to circuit breakers capable of extinguishing arcs. Background Technology

[0002] A circuit breaker is a switching device capable of closing, carrying, and interrupting current under normal circuit conditions, and capable of closing, carrying, and interrupting current under abnormal circuit conditions within a specified time. However, in DC power supply, when the power is turned on and off, the load in the circuit will generate an induced current equivalent to an inductance. When the circuit breaker opens, because the current in the inductance cannot change abruptly, the accumulated energy cannot be released and can only break down the air at the circuit breaker contacts, generating an electric arc to release the energy.

[0003] There are two main types of arc extinguishing methods: physical arc extinguishing and electronic arc extinguishing. The first type, physical arc extinguishing, is exemplified by the Chinese invention entitled "Electromagnetic Contactor" (publication number CN104737264A), which improves circuit breaking performance by shortening the arc dwell time. This is specifically achieved by setting up a sealed arc extinguishing chamber and increasing the area of ​​the contact end face. Figure 1 The diagram shown is a structural diagram of an existing electromagnetic contactor. The numbers in the attached diagram are explained as follows:

[0004] 10 Electromagnetic contactor

[0005] 100 contact device

[0006] 101 Contact Mechanism

[0007] 102 Arc Extinction Chamber

[0008] 105 Fixed contact support insulating substrate

[0009] 111, 112 Fixed contacts

[0010] 115 C-shaped part

[0011] 118 Fixed contact section

[0012] 118a Contact Section

[0013] 118b Chamfer Shape

[0014] 118c contact end face

[0015] 121 Insulating Cover

[0016] 122 L-shaped plate section

[0017] 122a Upper cover (opposite face)

[0018] 122b Side Cover Section

[0019] 130 Movable contact section

[0020] 130a Contact Section

[0021] 130b chamfer shape

[0022] 130c contact end face

[0023] 132 movable contacts

[0024] 141 Magnet Storage Bag

[0025] 143 Permanent magnets for arc suppression

[0026] 145 Arc Extinguishing Space

[0027] The advantage of this solution is that the switch can be physically disconnected, achieving physical isolation. Of course, there are other physical arc-extinguishing methods, such as using gas or oil to extinguish the arc, vacuum arc extinguishing, multi-break arc extinguishing, and metal arc-extinguishing grids. These physical arc-extinguishing methods extinguish the arc by suppressing, reducing, or rigidly resisting it; they can only reduce the arc, not fundamentally solve the problem. The presence of an arc will erode the contacts, reducing the circuit breaker's lifespan. Furthermore, the presence of an arc can easily cause electric shock accidents and even electrical fires, posing significant threats to personal safety and property.

[0028] The second type is electronic arc extinguishing, as exemplified by the invention entitled "An Arc Extinguishing Device for High-Power DC Switches" (publication number CN107332222A) and the Chinese invention entitled "A DC Dedicated Socket with Built-in Arc Extinguishing Device and its Matching Plug" (application number CN201521075698), among others. The advantage of this type of electronic arc extinguishing solution is that it can feed the inductor current in the circuit back to the input terminal through the freewheeling circuit of the arc extinguishing circuit set in the circuit breaker, allowing the energy in the circuit to be fully released. No arc is generated when the circuit breaker is opened. However, electronic arc extinguishing methods lack physical isolation; an electrical connection is generated when the switch is opened, and reverse leakage current exists. Furthermore, due to the voltage withstand rating limitations of electronic components, it cannot withstand high voltages. Summary of the Invention

[0029] In view of this, the technical problem to be solved by the present invention is to provide a circuit breaker that can achieve physical isolation and withstand high voltage, and can also achieve electronic arc extinguishing.

[0030] The improved concept of this invention is to achieve the switching of two pairs of switches in the arc extinguishing circuit in a timely manner through the design of the clamping circuit. The circuit breaker does not generate an electric arc when closing or opening, thereby achieving both physical isolation and high voltage resistance, as well as electronic arc extinguishing and improving the service life of the product.

[0031] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0032] A circuit breaker includes an arc-extinguishing device, which comprises an arc-extinguishing circuit and a mechanical operating mechanism linked to the arc-extinguishing circuit. The mechanical operating mechanism includes a stationary contact and a moving contact. The moving contact includes a first moving contact and a second moving contact. The first moving contact and the second moving contact operate asynchronously. The first moving contact is used to connect a low-voltage circuit, and the second moving contact is used to connect a high-voltage circuit. The arc-extinguishing circuit includes switches J1, J2, J3, and J4, diodes D1 and D3. One end of switch J3 is connected to the positive input terminal, and the other end of switch J3 is connected to one end of switch J4. The other end of switch J4 is connected to the positive output terminal. One end of switch J1 is connected to the negative input terminal, and the other end of switch J1 is connected to one end of switch J2. The other end of switch J2 is connected to the negative output terminal. The anode of diode D1 is connected to the anode of switch J1. The cathode of diode D1 is connected to the positive input terminal, and the anode of diode D2 is connected to the negative input terminal and one end of switch J1. The cathode of diode D2 is connected to the other end of switch J3 and one end of switch J4. Switches J1 and J3 form a first pair of switches that operate synchronously and are connected to the first moving contact. Switches J2 and J4 form a second pair of switches that operate synchronously and are connected to the second moving contact. When the circuit breaker is closed, the second moving contact closes first to achieve the first closing of the second pair of switches. Then the first moving contact closes to achieve the subsequent closing of the first pair of switches. When the circuit breaker is opened, the first moving contact opens first to achieve the first opening of the first pair of switches. Then the second moving contact opens to achieve the subsequent opening of the second pair of switches.

[0033] The present invention also provides a circuit breaker, including a mechanical operating mechanism linked with an arc-extinguishing circuit. The mechanical operating mechanism includes a first moving contact (1), a first moving contact spring (2), a connecting rod (3), a second moving contact spring (4), a second moving contact (5), and stationary contacts (6, 7, 8, 9). The first moving contact (1) and the second moving contact (5) of the mechanical operating mechanism are symmetrically arranged in parallel along the longitudinal axis of the connecting rod, and the distance between the bottom surface of the first moving contact (1) and the stationary contact is greater than the distance between the second moving contact (5) and the stationary contact. The actions of the first moving contact (1) and the second moving contact (5) are asynchronous. The first moving contact (1) is used to connect the weak current circuit, and the second moving contact (5) is used to connect the strong current circuit. When the circuit breaker is closed, the connecting rod (3) moves downward, and the bottom surface of the second moving contact (5) first... The first moving contact (1) contacts the stationary contacts (6, 7) to achieve the first closing of the second pair of switches. When the connecting rod (3) continues to move downward, the second moving contact (5) continues to contact the stationary contacts (6, 7) under the action of the second moving contact spring (4), and the bottom surface of the first moving contact (1) contacts the stationary contacts (8, 9) to achieve the second closing of the first pair of switches. When the circuit breaker is disconnected, the connecting rod (3) moves upward, the bottom surface of the first moving contact (1) separates from the stationary contacts (8, 9), and the second moving contact (5) remains in contact with the stationary contacts (6, 7) under the action of the second moving contact spring (4) to achieve the first opening of the first pair of switches. When the connecting rod (3) continues to move upward, the bottom surface of the second moving contact (5) separates from the stationary contacts (6, 7) to achieve the second opening of the second pair of switches.

[0034] The present invention further provides a circuit breaker, including a mechanical operating mechanism linked to an arc-extinguishing circuit. The mechanical operating mechanism includes a first moving contact (1), a second moving contact (5), a stationary contact (6), and a connecting frame. The first moving contact (1), the second moving contact (5), and the stationary contact (6) of the mechanical operating mechanism are arranged in parallel in a longitudinal parallel manner perpendicular to the connecting frame. The actions of the first moving contact (1) and the second moving contact (5) are asynchronous. The first moving contact (1) is used to connect a weak current circuit, and the second moving contact (5) is used to connect a strong current circuit. When the circuit breaker is closed, under the action of an external force applied toward the stationary contact, the second moving contact... Point (5) moves and closes towards the first moving contact (1) to achieve the first closing of the second pair of switches; with continued application of external force, the second moving contact (5) and the first moving contact (1) move and close together towards the stationary contact (6) to achieve the subsequent closing of the first pair of switches; when the circuit breaker is disconnected, the external force is released, the first moving contact (1) and the stationary contact (6) separate first, and the second moving contact (5) and the first moving contact (1) remain closed to achieve the first disconnection of the first pair of switches; then the external force is released again, and the second moving contact (5) and the first moving contact (1) separate to achieve the subsequent disconnection of the second pair of switches.

[0035] This invention further provides a control method for a circuit breaker, which controls the closing / opening of two pairs of switch groups in the arc-extinguishing circuit of the circuit breaker by controlling the closing / opening of two moving contacts of the mechanical operating mechanism in the circuit breaker according to a set timing sequence. The method includes: the actions of the two moving contacts of the mechanical operating mechanism in the circuit breaker are asynchronous; wherein, the first moving contact is connected to the first pair of switch groups for connecting a low-voltage circuit; the second moving contact is connected to the second pair of switch groups for connecting a high-voltage circuit; the closing action sequence of the circuit breaker is that the second moving contact and the stationary contact close first to achieve the first closing of the second pair of switch groups; then the first moving contact and the stationary contact close to achieve the subsequent closing of the first pair of switch groups; the opening action sequence of the circuit breaker is that the first moving contact and the stationary contact open first to achieve the first opening of the first pair of switch groups; then the second moving contact and the stationary contact open to achieve the subsequent opening of the second pair of switch groups.

[0036] The present invention further provides a control method for a circuit breaker, which realizes the closing / opening control of two pairs of switch groups in the arc-extinguishing circuit of the circuit breaker by controlling the closing / opening of two moving contacts of the mechanical operating mechanism in the circuit breaker according to a set timing sequence. The method includes: the two pairs of switch groups in the arc-extinguishing circuit of the circuit breaker are asynchronous; wherein, the first pair of switch groups is connected to the first moving contact and is used to connect the low-voltage circuit; the second pair of switch groups is connected to the second moving contact and is used to connect the high-voltage circuit; the closing control timing of the circuit breaker is that the second pair of switch groups closes first, and the first pair of switch groups closes after a set time period; the opening control timing of the circuit breaker is that the first pair of switch groups opens first, and the second pair of switch groups opens after a set time period.

[0037] In this invention, because the inductor current cannot change abruptly in a DC circuit, when the circuit breaker opens, switch J1 (J3) opens first, while switch J2 (J4) remains connected and conducting. Through the arc-extinguishing circuit, the freewheeling current formed in the circuit is fed back to the DC line, realizing the lossless recovery of the energy stored in the inductor coil in the load when the contactor opens. Switch J2 (J4) opens subsequently, achieving zero-voltage shutdown and providing physical isolation. When the circuit breaker closes, switch J2 (J4) closes and conducts first, followed by switch J1 (J3), achieving zero-current conduction and realizing the arc-extinguishing function, thus extending the product life. Attached Figure Description

[0038] Figure 1 This is a structural diagram of an electromagnetic contactor using the existing physical arc extinguishing method;

[0039] Figure 2 This is a circuit diagram of an existing electronic arc extinguishing method suitable for high-power DC switching arc extinguishing devices;

[0040] Figure 3A structural diagram of a DC-specific socket with a built-in arc extinguishing device and its matching plug for existing electronic arc extinguishing methods;

[0041] Figure 4 This is a circuit diagram of the arc-extinguishing device of the circuit breaker of the present invention;

[0042] Figure 5 This is a timing diagram of the switch in the arc-extinguishing device of the circuit breaker of the present invention;

[0043] Figure 6 This is a structural diagram of the mechanical operating mechanism of the arc-extinguishing device of the circuit breaker according to the first embodiment of the present invention;

[0044] Figure 7 This is a structural diagram of the mechanical operating mechanism of the arc extinguishing device of the circuit breaker according to the second embodiment of the present invention. Detailed Implementation

[0045] Those skilled in the art will know that using physical structures to extinguish arcs is a conventional method for extinguishing arcs in circuit breakers. This invention arises from the applicant's long-term commitment to research on electronic circuit technology and structural design, thereby breaking through the existing mindset of the technology. The inventive concept is to achieve the ability of switches to work in sequence through structural design, in conjunction with the arc extinguishing circuit, thereby achieving arc-free circuit switching, increasing product lifespan, simple structure, and low cost.

[0046] like Figure 4 The diagram shown is a circuit diagram of the arc-extinguishing device of the circuit breaker of the present invention. A circuit breaker includes an arc-extinguishing device, which includes an arc-extinguishing circuit and a mechanical operating mechanism linked to the arc-extinguishing circuit. The mechanical operating mechanism includes a stationary contact and a moving contact. The moving contact includes a first moving contact and a second moving contact. The actions of the first moving contact and the second moving contact are asynchronous. The first moving contact is used to connect a weak current circuit (weak current refers to electrical energy in the control system, and the weak current circuit is the control system circuit), and the second moving contact is used to connect a strong current circuit (strong current refers to electrical energy in the power system, and the strong current circuit is the power energy circuit).

[0047] The arc-extinguishing circuit includes switches J1, J2, J3, and J4, diodes D1 and D3. One end of switch J3 is connected to the positive input terminal, and the other end of switch J3 is connected to one end of switch J4. The other end of switch J4 is connected to the positive output terminal. One end of switch J1 is connected to the negative input terminal, and the other end of switch J1 is connected to one end of switch J2. The other end of switch J2 is connected to the negative output terminal. The anode of diode D1 is connected to both the other end of switch J1 and one end of switch J2, and the cathode of diode D1 is connected to the positive input terminal. The anode of diode D2 is connected to both the negative input terminal and one end of switch J1, and the cathode of diode D2 is connected to both the other end of switch J3 and one end of switch J4.

[0048] Switches J1 and J3 form a first pair of switches that operate synchronously and are used to connect with the first moving contact. Switches J2 and J4 form a second pair of switches that operate synchronously and are used to connect with the second moving contact.

[0049] When the circuit breaker is closed, the second moving contact closes first to achieve the first closure of the second pair of switches; then the first moving contact closes to achieve the subsequent closure of the first pair of switches.

[0050] When the circuit breaker is tripped, the first moving contact opens first to disconnect the first pair of switches; then the second moving contact opens to disconnect the second pair of switches.

[0051] The working principle of the circuit breaker of this invention is as follows:

[0052] The closing / opening control of the two pairs of switches in the arc-extinguishing circuit of the circuit breaker is achieved by controlling the closing / opening of the two moving contacts of the mechanical operating mechanism in the circuit breaker according to a set timing sequence. The operation of the two moving contacts of the mechanical operating mechanism in the circuit breaker is asynchronous. The two moving contacts include a first moving contact and a second moving contact. The first moving contact is connected to the first pair of switches and is used to connect the low-voltage circuit. The second moving contact is connected to the second pair of switches and is used to connect the high-voltage circuit. The closing sequence of the circuit breaker is as follows: the second moving contact closes first with the stationary contact to achieve the first closure of the high-voltage physical circuit, thereby achieving the first closure of the second pair of switches. Then, the first moving contact closes with the stationary contact to achieve the closure of the low-voltage circuit, that is, to energize the circuit breaker, thereby achieving the subsequent closure of the first pair of switches. The circuit breaker's disconnection sequence is as follows: the first moving contact disconnects from the stationary contact to disconnect the weak current circuit first, i.e., the circuit breaker is de-energized, thus disconnecting the first pair of switch groups first; then the second moving contact disconnects from the stationary contact to disconnect the strong current physical circuit later, thus disconnecting the second pair of switch groups later.

[0053] From a technical perspective, the operating sequence of the two moving contacts in the mechanical operating mechanism of the circuit breaker is as follows: For closing, the second moving contact closes first with the stationary contact to achieve the initial closing of the second pair of switches; then the first moving contact closes with the stationary contact to achieve the subsequent closing of the first pair of switches. For opening, the first moving contact opens first with the stationary contact to achieve the initial opening of the first pair of switches; then the second moving contact opens with the stationary contact to achieve the subsequent opening of the second pair of switches.

[0054] The control timing sequence of the two pairs of switches in the arc-extinguishing circuit of the circuit breaker is as follows: Figure 5 As shown, the closing control sequence of the circuit breaker is that the second pair of switches closes first, and the first pair of switches closes after a set time period t1; the opening control sequence of the circuit breaker is that the first pair of switches opens first, and the second pair of switches opens after a set time period t1.

[0055] To better illustrate the present invention, the principles and implementation methods of the invention will be described in detail below with reference to the accompanying drawings.

[0056] First Embodiment

[0057] like Figure 6 The diagram shown is a structural diagram of the mechanical operating mechanism of the arc-extinguishing device of the circuit breaker of the present invention, and is combined with... Figure 4 As shown, a circuit breaker includes an arc-extinguishing device, which includes an arc-extinguishing circuit and a mechanical operating mechanism linked to the arc-extinguishing circuit. The mechanical operating mechanism includes a moving contact 1, a moving contact spring 2, a connecting rod 3, a moving contact spring 4, a moving contact 5, a stationary contact 6, a stationary contact 7, a stationary contact 8, and a stationary contact 9, which are arranged in parallel with the same structure. The moving contact 1', moving contact spring 2', connecting rod 3', moving contact spring 4', moving contact 5', stationary contact 6', stationary contact 7', stationary contact 8', and stationary contact 9' are also shown.

[0058] When link 3 moves downward, it also moves moving contact 1, moving contact spring 2, moving contact 5, and moving contact spring 4 downward. Because the distance between the bottom surface of moving contact 1 and the stationary contact is greater than the distance between the bottom surface of moving contact 5 and the stationary contact, during the downward movement of link 3, the bottom surface of moving contact 5 contacts stationary contacts 6 and 7 first. This is to achieve the initial closing of the second pair of switches, which is equivalent to... Figure 4 Switches J2 and J4 are closed first.

[0059] As the connecting rod 3 continues to move downwards, the moving contact 5, under the action of the moving contact spring 4, continues to maintain contact with the stationary contacts 6 and 7, and the bottom surface of the moving contact 1 contacts the stationary contacts 8 and 9, thereby achieving the subsequent closure of the first pair of switches, equivalent to... Figure 4 After the intermediate switches J1 and J3 are closed, the circuit breaker closing function is achieved.

[0060] When link 3 moves upward, the bottom surface of moving contact 1 separates from stationary contacts 8 and 9 first. Moving contact 5, under the action of moving contact spring 4, remains in contact with stationary contacts 6 and 7, thus achieving the first disconnection of the first pair of switches, equivalent to... Figure 4 First, separate the switches J1 and J3.

[0061] As link 3 continues to move upward, the bottom surface of moving contact 5 separates from stationary contacts 6 and 7, thereby achieving the subsequent disconnection of the second pair of switches, equivalent to... Figure 4 Switches J2 and J4 are then disconnected.

[0062] This embodiment may employ, but is not limited to, the following methods. Figure 6 The structure shown is illustrated, and the schematic diagram of the arc-extinguishing circuit can be found in [reference needed]. Figure 4This embodiment uses two switches as a pair of switch groups for illustration. Figure 5 In the circuit, switch J1 (J3) is equivalent to moving contact 1 (1'), and switch J2 (J4) is equivalent to moving contact 5 (5').

[0063] like Figure 6 The diagram shows the timing of the switches in the arc-extinguishing device of the circuit breaker of this invention. The working principle of the arc-extinguishing device of the circuit breaker in this embodiment is as follows: When the circuit breaker is closed, the moving contact 5 (5') of the high-voltage circuit closes first, so as to realize the first closure of the mechanical contacts in the high-voltage physical circuit, that is, to realize the first closure of switch J2 (J4). After a set time period t1, the moving contact 1 of the low-voltage circuit closes, so as to realize the closure of the mechanical contacts in the low-voltage circuit, that is, to energize the circuit breaker, thereby realizing the subsequent closure of switch J1 (J3), so that the moving contact 5 (5') in the high-voltage circuit completes the closing action without being energized, thereby ensuring that the moving contact 5 (5') of switch J2 (J4) in the high-voltage physical circuit of the circuit breaker is in a zero-current conduction condition at the moment the circuit breaker is closed. When the circuit breaker is disconnected, the moving contact 1 (1') of the weak current circuit opens first, so that the mechanical contacts in the weak current circuit of the circuit breaker are disconnected first, that is, the circuit breaker is de-energized, thereby realizing the first disconnection of switch J1 (J3). The current of the inductor in the DC circuit cannot change abruptly, and the energy stored in the circuit is completely fed back to the DC circuit by the freewheeling circuit formed by diodes D1 and D2, realizing the lossless recovery of the stored energy when the circuit breaker is disconnected. The duration of the set time period t1 is set according to the time required for this energy recovery process. After a set time period t1, the moving contact 5 (5') of the high-voltage circuit is disconnected to realize the subsequent disconnection action of the mechanical contact in the high-voltage physical circuit, thereby realizing the subsequent disconnection of switch J2 (J4). In this way, when switch J1 (J3) is disconnected first, and switch J2 (J4) is disconnected later, there is no current flowing through the circuit breaker circuit. This ensures that the moving contact 5 (5') of switch J2 (J4) in the high-voltage physical circuit of the circuit breaker is in the condition of zero current and zero voltage at the moment the circuit breaker is disconnected. This realizes that the mechanical contact of the circuit breaker has the arc extinguishing function when the circuit breaker is closed and opened. Moreover, the disconnection of switch J2 (J4) realizes physical isolation. The structure is simple, the cost is low, and the service life of the product is increased.

[0064] Second Embodiment

[0065] like Figure 7 As shown in the embodiment of the present invention, it includes a moving contact 1, a moving contact 5, and a fixed contact (also called a stationary contact) 6. Under the action of an external force, the moving contact 5 moves toward the moving contact 1 and closes, which is equivalent to... Figure 4 When the switch J2 (J4) closes first, and external force is continued to be applied, moving contacts 5 and 1 move towards and close the fixed contact 6, which is equivalent to... Figure 4When the external force is released, the moving contact 5, moving contact 1, and fixed contact 6 open first, which is equivalent to the closing of the switch J1 (J3); Figure 4 The switch J1 (J3) opens first, then moving contact 5 and moving contact 1 open, which is equivalent to... Figure 4 The subsequent disconnection of switch J2 (J4) is achieved through the arc-extinguishing circuit in the circuit. Similarly, switches J1 and J2 can be switched in a certain sequence without generating an electric arc in the circuit. Physical switch J2 (J4) achieves zero-current opening and zero-voltage disconnection, realizing the arc-extinguishing function of the mechanical contacts in the circuit breaker and increasing the service life of the product.

[0066] The above description of the embodiments is only to enable those skilled in the art to understand and use the present invention. The present invention is not limited to the above embodiments. Improvements and modifications made by those skilled in the art based on the present invention without departing from the concept of the present invention are all within the protection scope of the present invention.

Claims

1. A circuit breaker, comprising an arc-extinguishing device, characterized in that: The arc-extinguishing device includes an arc-extinguishing circuit and a mechanical operating mechanism linked to the arc-extinguishing circuit. The mechanical operating mechanism includes stationary contacts and moving contacts. The moving contact includes a first moving contact and a second moving contact. The actions of the first moving contact and the second moving contact are asynchronous. The first moving contact is used to connect the low-voltage circuit, and the second moving contact is used to connect the high-voltage circuit. The arc extinguishing circuit includes switches J1, J2, J3, and J4, diode D1, and diode D3. One end of switch J3 is connected to the positive input terminal, the other end of switch J3 is connected to one end of switch J4, and the other end of switch J4 is connected to the positive output terminal. One end of switch J1 is connected to the negative input terminal, and the other end of switch J1 is connected to one end of switch J2. The other end of switch J2 is connected to the negative output terminal. The anode of diode D1 is connected to both the other end of switch J1 and one end of switch J2, and the cathode of diode D1 is connected to the positive input terminal. The anode of diode D2 is connected to both the negative input terminal and one end of switch J1, and the cathode of diode D2 is connected to both the other end of switch J3 and one end of switch J4. Switches J1 and J3 form a first pair of switches that operate synchronously and are used to connect with the first moving contact. Switches J2 and J4 form a second pair of switches that operate synchronously and are used to connect with the second moving contact. When the circuit breaker is closed, the second moving contact closes first, so as to achieve the first closure of the second pair of switches; After a set time period, the first moving contact closes to achieve the subsequent closing of the first pair of switch groups, thereby enabling zero-current conduction of the high-voltage switches J2 and J4. When the circuit breaker is tripped, the first moving contact opens first to achieve the first tripping of the first pair of switches; after a set time period, the second moving contact opens to achieve the second tripping of the second pair of switches, thereby achieving zero-voltage shutdown of the high-voltage switches J2 and J4.

2. A control method for a circuit breaker, wherein the closing / opening control of two pairs of switches in the arc-extinguishing circuit of the circuit breaker is achieved by controlling the closing / opening of two moving contacts of the mechanical operating mechanism in the circuit breaker according to a set timing sequence, the method comprising: The two moving contacts of the mechanical operating mechanism in the circuit breaker operate asynchronously; the first moving contact is connected to the first pair of switch groups and is used to connect the low-voltage circuit; the second moving contact is connected to the second pair of switch groups and is used to connect the high-voltage circuit. The closing sequence of the circuit breaker is as follows: the second moving contact and the stationary contact close first to achieve the initial closing of the second pair of switch groups; then the first moving contact and the stationary contact close to achieve the subsequent closing of the first pair of switch groups. The circuit breaker's disconnection sequence is as follows: the first moving contact disconnects from the stationary contact first, thus disconnecting the first pair of switches; then the second moving contact disconnects from the stationary contact, thus disconnecting the second pair of switches.

3. A control method for a circuit breaker, wherein the closing / opening control of two pairs of switches in the arc-extinguishing circuit of the circuit breaker is achieved by controlling the closing / opening of two moving contacts of the mechanical operating mechanism in the circuit breaker according to a set timing sequence, the method comprising: The two pairs of switch groups in the arc-extinguishing circuit of the circuit breaker are asynchronous; the first pair of switch groups is connected to the first moving contact and is used to connect the low-voltage circuit; the second pair of switch groups is connected to the second moving contact and is used to connect the high-voltage circuit. The closing control sequence of the circuit breaker is that the second pair of switches closes first, and the first pair of switches closes after a set time period. The circuit breaker's disconnection control sequence is that the first pair of switches disconnects first, and the second pair of switches disconnects after a set time period.

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