Patent Description:
At present, power supply systems are widely used, and a circuit breaker is often used in this type of system to implement functions such as power distribution and protection. The circuit breaker may be applied to a direct current power supply system or an alternating current power supply system. Conventional circuit breakers include a mechanical circuit breaker and a solid-state circuit breaker, but both the mechanical circuit breaker and the solid-state circuit breaker have their own drawbacks. The mechanical circuit breaker needs many linkage apparatuses in a switching process, for example, a spring, a hook, a lever, and an armature, and linkage time is long. In addition, the mechanical circuit breaker uses a contact to implement circuit conduction and disconnection, and an electric arc is generated in a contact gap when the mechanical circuit breaker is opened, and arcing time is long. The electric arc is a cylindrical gas that emits strong light and conducts electricity and that is generated in the contact gap when the mechanical circuit breaker is opened. The circuit breaker is opened after the electric arc is extinguished and the contact gap becomes an insulation medium. The arcing time is a time period during which the electric arc is generated in each phase of the circuit breaker when the circuit breaker is opened. For the above reasons, the mechanical circuit breaker can only implement breaking time in milliseconds (ms), and a short-circuit breaking speed is slow. The solid-state circuit breaker uses a power electronic device instead of a switch to perform conduction and disconnection, and the solid-state circuit breaker can implement very fast switching time. However, due to a limitation of a current manufacturing process of an electronic power switch, a conduction loss of the solid-state circuit breaker is high, and a water-cooled heat sink is often used, which results in an increased volume and costs.

Therefore, the industry urgently needs a circuit breaker that can implement a faster short-circuit breaking speed, a lower conduction loss, and lower costs. <CIT> describes a switching assembly that includes a switch portion having a fixed electrode and a movable electrode which are separable. <CIT> describes a switching apparatus includes a pair of fixed coils and a pair of movable coils, with one pair being disposed between the other pair. <CIT> describes a fast-acting switching device with a drive coil intended for connection to a power source.

This application provides a circuit breaker and a power supply system, which can optimize switching performance of the circuit breaker.

According to a first aspect, a circuit breaker according to the independent claim <NUM> is provided.

The circuit breaker includes the mechanical switch circuit, and the mechanical switch circuit controls the current directions in the movable coil and the stationary coil, so that the movable coil and the stationary coil can attract or disconnect from each other, and the movable coil can drive the movable contact to be in contact with or disconnected from the stationary contact. Finally, conduction and disconnection of the mechanical switch circuit is implemented. The switching manner simplifies linkage apparatuses and optimizes switching performance of the circuit breaker. For example, switching time of the mechanical switch circuit can be reduced, thereby reducing switching time of the circuit breaker.

With reference to the first aspect, in a possible implementation, the movable coil and the movable contact are a fixed connection structure, or a linkage structure is disposed between the movable coil and the movable contact.

The movable coil and the movable contact are the fixed structure, or the linkage structure is disposed between the movable coil and the movable contact, so that when the movable coil moves, the movable contact can be driven to move together to implement conduction and disconnection of the mechanical switch circuit. The switching manner simplifies linkage apparatuses, and switching time of the mechanical switch circuit can be reduced, thereby reducing switching time of the circuit breaker.

With reference to the first aspect, in a possible implementation, the circuit breaker further includes a solid-state switch circuit, where the solid-state switch circuit is connected in parallel to the mechanical switch circuit, when the circuit breaker is closed, the solid-state switch circuit is conducted prior to the mechanical switch circuit, and when the circuit breaker is opened, the mechanical switch circuit is disconnected prior to the solid-state switch circuit.

The circuit breaker uses a form in which the mechanical switch circuit is connected in parallel to the solid-state switch circuit, and the solid-state switch circuit can avoid an electric arc generated in the contact when the mechanical switch circuit is conducted or disconnected, thereby shortening arcing time, improving a switching speed of the circuit breaker, and prolonging a service life of the mechanical switch circuit.

With reference to the first aspect, in a possible implementation, the movable coil is specifically configured to: when the currents flowing through the movable coil and the stationary coil are in the same direction, stay away from the stationary coil, and drive the movable contact to be disconnected from the stationary contact; and when the currents flowing through the movable coil and the stationary coil are in opposite directions, approach the stationary coil, and drive the movable contact to be in contact with the stationary contact.

With reference to the first aspect, in a possible implementation, the busbar includes a first busbar and a second busbar, the stationary contact includes a first stationary contact and a second stationary contact, the first stationary contact is fastened on the first busbar, and the second stationary contact is fastened on the second busbar.

According to the invention, a wound coil of the movable coil uses a first conductive material, a wound coil of the stationary coil uses a second conductive material, and a density of the first conductive material is less than a density of the second conductive material.

The wound coil of the movable coil uses the conductive material with the low density, to reduce quality of the movable coil, and further reduce energy required when the movable coil moves, to save power of the mechanical switch circuit.

With reference to the first aspect, in a possible implementation, the movable coil and the stationary coil are connected in series with each other.

With reference to the first aspect, in a possible implementation, the movable coil is coaxial with the movable contact, and the movable coil can drive the movable contact to move up and down in an axial direction.

With reference to the first aspect, in a possible implementation, a protrusion part is disposed on a first surface of the movable contact, and the first surface of the movable contact is configured to be in contact with the stationary contact.

The protrusion part is disposed along the first surface of the movable contact, to ensure a reliable connection of the movable and stationary contacts, thereby improving switching sensitivity of the circuit breaker.

With reference to the first aspect, in a possible implementation, the movable coil and the movable contact are connected by using an insulation material.

According to a second aspect, a power supply system is provided. The power supply system includes the circuit breaker according to the first aspect or any possible implementation of the first aspect.

For ease of understanding, several terms used in this application are first described.

Circuit breaker: can be applied to a direct current power supply system or an alternating current power supply system, and is a switch apparatus that can conduct, carry, and disconnect a current under a normal loop condition and can conduct, carry, and disconnect a current under an abnormal loop condition within specified time. The circuit breaker has overload, short-circuit, and undervoltage protection functions, and has a capability to protect a line and a power supply.

Solid-state circuit breaker: is also known as a solid-state switch circuit. The solid-state circuit breaker can be a circuit breaker using a transistor as a switching element, which implements control of the circuit breaker by a non-contact switch. A switch module mainly includes power electronic devices, which are opened and closed to complete conduction and disconnection control on a current in a normal loop.

Mechanical circuit breaker: is also known as a mechanical switch circuit and is a circuit breaker that uses a mechanical linkage apparatus to implement a switching function. The mechanical circuit breaker usually includes a contact system, an arc-extinguishing system, an operating mechanism, a trip unit, and the like.

Short-circuit breaking capability: refers to a maximum current value that a circuit breaker can break without being damaged.

An insulated gate bipolar transistor (insulated gate bipolar transistor, IGBT) is a composite full-controlled voltage driven power semiconductor device that includes a bipolar junction transistor (bipolar junction transistor, BJT) and a metal-oxide-semiconductor field-effect transistor (metal-oxide-semiconductor field-effect transistor, MOSFET), and has advantages of a high input impedance of the MOSFET and a low conduction voltage drop of the BJT.

<FIG> is a schematic diagram of a circuit breaker <NUM> according to an embodiment of this application. As shown in <FIG>, the circuit breaker <NUM> includes a mechanical switch circuit <NUM>.

The mechanical switch circuit <NUM> includes a busbar <NUM>, a power module <NUM>, and a drive module <NUM>. The busbar <NUM> is also referred to as a bus bank, is a main power supply line in a power device, has a large current flow capability, and usually includes a copper bar or an aluminum bar.

The power module <NUM> includes a movable contact <NUM> and a stationary contact <NUM>, the stationary contact <NUM> is electrically connected to the busbar <NUM>, and the movable contact <NUM> is movable. When the movable contact <NUM> is in contact with the stationary contact <NUM>, the mechanical switch circuit <NUM> is conducted, and when the movable contact <NUM> is disconnected from the stationary contact <NUM>, the mechanical switch circuit <NUM> is disconnected. Optionally, the movable contact <NUM> and the stationary contact <NUM> may alternatively be collectively referred to as a movable contact system.

Optionally, the busbar <NUM> may include a first busbar <NUM>-<NUM> and a second busbar <NUM>-<NUM>, and the stationary contact <NUM> includes a first stationary contact <NUM>-<NUM> and a second stationary contact <NUM>-<NUM>. The first stationary contact <NUM>-<NUM> is connected to the first busbar <NUM>-<NUM>, and the second stationary contact <NUM>-<NUM> is connected to the second busbar <NUM>-<NUM>. The first stationary contact <NUM>-<NUM> and the second stationary contact <NUM>-<NUM> are in an electrically disconnected state. Therefore, when the stationary contact <NUM> is disconnected from the movable contact <NUM>, the first busbar <NUM>-<NUM> and the second busbar <NUM>-<NUM> are in a disconnected state, that is, the mechanical switch circuit <NUM> is in a disconnected state. When the stationary contact <NUM> is in contact with the movable contact <NUM>, the movable contact <NUM> connects the first stationary contact <NUM>-<NUM> and the second stationary contact <NUM>-<NUM> to provide a low-resistance path between the first busbar <NUM>-<NUM> and the second busbar <NUM>-<NUM>, so that the first busbar <NUM>-<NUM> is electrically connected to the second busbar <NUM>-<NUM>, that is, the mechanical switch circuit <NUM> is in a conducting state.

In some examples, the stationary contact <NUM> and the busbar <NUM> are of an integrated structure, or the stationary contact <NUM> is a part of the busbar <NUM>.

The drive module <NUM> includes a switch circuit, a movable coil <NUM>, and a stationary coil <NUM>. The movable coil <NUM> and the stationary coil <NUM> are placed adjacently, the switch circuit is configured to control current directions of the movable coil <NUM> and the stationary coil <NUM>, and the movable coil <NUM> and the stationary coil <NUM> attract or repel each other based on whether the current directions are the same, so that the movable coil <NUM> drives the movable contact <NUM> to be in contact with or disconnected from the stationary contact <NUM>.

The movable coil <NUM> is designed to drive the movable contact <NUM> to move. For example, the movable contact <NUM> and the movable coil <NUM> are a fixed connection structure, or a linkage structure is disposed between the movable contact <NUM> and the movable coil <NUM>.

A specific connection manner between the movable contact <NUM> and the movable coil <NUM> is not limited in this embodiment of this application, provided that the movable coil <NUM> can drive the movable contact <NUM> to move when moving.

Optionally, the movable contact <NUM> and the movable coil <NUM> may be connected by using an insulation material, that is, the movable contact <NUM> and the movable coil <NUM> are electrically insulated. For example, the insulation material may include epoxy resin.

In other words, the switch circuit may control the current directions of the movable coil <NUM> and the stationary coil <NUM> to be the same or opposite.

Optionally, a specific placement manner of the movable coil <NUM> and the stationary coil <NUM> is not limited in this embodiment of this application, provided that a distance between the movable coil <NUM> and the stationary coil <NUM> can enable the movable coil <NUM> and the stationary coil <NUM> to repel or attract each other.

In some examples, if the movable coil <NUM> and the stationary coil <NUM> are placed side by side, and when the currents flowing through the movable coil <NUM> and the stationary coil <NUM> are in the same direction, the movable coil <NUM> stays away from the stationary coil <NUM>, and drives the movable contact <NUM> to be disconnected from the stationary contact <NUM>; and when the currents flowing through the movable coil <NUM> and the stationary coil <NUM> are in the opposite directions, the movable coil <NUM> approaches the stationary coil <NUM>, and drives the movable contact <NUM> to be in contact with the stationary contact <NUM>.

It should be understood that when the current directions between two coils are the same, directions of magnetic fields generated between the two coils are opposite. Therefore, the coils attract each other. When the current directions between the two coils are opposite, directions of magnetic fields generated between the two coils are the same. Therefore, the coils repel each other.

It may be understood that the switch circuit, the movable coil <NUM>, and the stationary coil <NUM> form a drive system, and the movable coil <NUM>, the movable contact <NUM>, and the stationary contact <NUM> further form an armature system. In this application, an electromagnetic principle is used, so that the movable coil <NUM> drives the movable contact system to implement contact and disconnection, and switching time of the mechanical switch circuit <NUM> can be reduced.

It should be understood that the switching time of the mechanical switch circuit <NUM> is related to the distance between the movable coil <NUM> and the stationary coil <NUM>. The disconnection of the mechanical switch circuit <NUM> is used as an example. A shorter distance between the movable coil <NUM> and the stationary coil <NUM> indicates a faster speed at which the movable contact <NUM> is separated from the stationary contact <NUM>, a shorter delay time for the drive module <NUM> to start separation from the contact, and further, shorter switching time of the mechanical switch circuit <NUM>. The distance between the movable coil <NUM> and the stationary coil <NUM> is adjusted, so that modulation of the switching time of the mechanical switch circuit <NUM> can be implemented.

The mechanical switch circuit <NUM> uses the electromagnetic principle, so that the movable coil <NUM> drives the movable contact <NUM> to be in contact with or disconnected from the stationary contact <NUM>. The switching manner simplifies linkage apparatuses in a conventional mechanical switch circuit, and can optimize switching performance of the mechanical switch circuit <NUM>. For example, the switching time of the mechanical switch circuit <NUM> can be reduced, thereby reducing switching time of the circuit breaker <NUM>.

Still refer to <FIG>. The switch circuit may include a plurality of switches (S1 to S4), and the current directions of the movable coil <NUM> and the stationary coil <NUM> are controlled by controlling turn-on and turn-off among the plurality of switches.

In some examples, the plurality of switches may be controllable switches. Specifically, the controllable switch may include a full-controlled switch or a semi-controlled switch. The full-controlled switch is also referred to as a self-turn-off device, which is a power electronic device that can control both turn-on and turn-off of the power electronic device by using a control signal. The full-controlled switch includes, but is not limited to, a gate turn-off thyristor (gate-turn thyristor, GTO), an MOSFET, and an IGBT.

The semi-controlled switch is a power electronic device that can only control turn-on of the power electronic device, but cannot control turn-off of the power electronic device by using a control signal. The semi-controlled switch includes but is not limited to the following: a thyristor.

For example, the switch circuit in <FIG> includes a first switch S1 to a fourth switch S4. A first end of the drive module <NUM> is connected to a first end of the first switch S1 and a first end of the second switch S2, a second end of the first switch S1 is connected to a first end of the stationary coil <NUM>, a second end of the second switch S2 is connected to a second end of the stationary coil <NUM>, a first end of the third switch S3 is connected to the first end of the stationary coil <NUM>, a second end of the third switch S3 is connected to a first end of the movable coil <NUM>, a first end of the fourth switch S4 is connected to the second end of the stationary coil <NUM>, a second end of the fourth switch S4 is connected to the first end of the movable coil <NUM>, and a second end of the movable coil <NUM> is connected to a second end of the drive module <NUM>.

In <FIG>, the movable coil <NUM> and the stationary coil <NUM> are connected in series with each other during working and are placed side by side.

It should be understood that the switch circuit in <FIG> is merely used as an example, and the switch circuit in this application may alternatively be implemented in another manner, provided that the switch circuit has a function of controlling the current direction of the movable coil <NUM> and the current direction of the stationary coil <NUM>.

It should be understood that the circuit breaker <NUM> in <FIG> is merely used as an example. After proper deformation, the circuit breaker <NUM> may further include more or fewer functional modules and circuit components.

It should be understood that a connection between two components in this embodiment of this application may mean a direct connection, or may mean an indirect connection. In the case of the indirect connection, another unit, module, or component may be disposed between the two components.

<FIG> is a schematic diagram of a working state of a mechanical switch circuit <NUM> according to an embodiment of this application. The movable coil <NUM> and the stationary coil <NUM> in <FIG> attract each other. As shown in <FIG>, when the mechanical switch circuit <NUM> needs to be conducted, the first switch S1 and the fourth switch S4 may be controlled to be turned on, and the second switch S2 and the third switch S3 may be controlled to be turned off. A current sequentially flows through the first switch S1, the stationary coil <NUM>, the fourth switch S4, and the movable coil <NUM>. The current directions of the movable coil <NUM> and the stationary coil <NUM> are the same. Therefore, the movable coil <NUM> and the stationary coil <NUM> attract each other, and the movable coil <NUM> drives the movable contact to be in contact with the stationary contact.

<FIG> is a schematic diagram of a working state of a mechanical switch circuit <NUM> according to an embodiment of this application. The movable coil <NUM> and the stationary coil <NUM> in <FIG> repel each other. As shown in <FIG>, when the mechanical switch circuit <NUM> needs to be disconnected, the second switch S2 and the third switch S3 may be controlled to be turned on, and the first switch S1 and the fourth switch S4 may be controlled to be turned off. A current sequentially flows through the second switch S2, the stationary coil <NUM>, the third switch S3, and the movable coil <NUM>. The current directions of the movable coil <NUM> and the stationary coil <NUM> are opposite. Therefore, the movable coil <NUM> and the stationary coil <NUM> repel each other, and the movable coil <NUM> drives the movable contact to be disconnected from the stationary contact.

Optionally, turn-on and turn-off of the switch in the switch circuit may be controlled by a control module. The control module may be disposed in the mechanical switch circuit <NUM>, or may be independent of the mechanical switch circuit <NUM>. This is not limited in this embodiment of this application.

Optionally, as shown in <FIG>, the mechanical switch circuit <NUM> further includes an energy storage module <NUM>. The energy storage module <NUM> is configured to provide a current for the drive module <NUM>, or provide, for the drive module <NUM>, a current that flows through the movable coil <NUM> and the stationary coil <NUM>.

In some examples, the energy storage module <NUM> may include a capacitor C1, and the capacitor C1 is configured to store an electric charge and provide a current. For example, the capacitor C1 may obtain power from the busbar <NUM> and store the electric charge. Alternatively, the capacitor C1 may obtain power in another manner, for example, obtain power from a battery. This is not limited in this application. The capacitor C1 may provide a transient-state large current, to implement fast conduction and disconnection of the mechanical switch circuit <NUM>.

Optionally, a first end of the capacitor C1 is configured to connect to a first end of the drive module <NUM>, and a second end of the capacitor C1 is configured to connect to a second end of the drive module <NUM>.

Optionally, the capacitor C1 may be an electrolytic capacitor or a thin film capacitor, or may be a capacitor of another type.

Further, the energy storage module <NUM> further includes a diode D5, and the diode D5 and the capacitor C1 are in a parallel connection relationship. An anode of the diode D5 is connected to the second end of the capacitor C1, and a cathode of the diode D5 is connected to the first end of the capacitor C1. The diode D5 connected in parallel at two ends of C1 can improve discharge efficiency of C1, thereby increasing a switching speed of the mechanical switch circuit <NUM>.

Optionally, the energy storage module <NUM> may alternatively use another implementation, provided that the energy storage module <NUM> can implement a function of providing the current for the movable coil <NUM> and the stationary coil <NUM>. For example, the energy storage module <NUM> may also include a battery, and the current is provided by using the battery. Alternatively, the energy storage module <NUM> may further include a boost converter or a buck converter, to perform level conversion on a received voltage, and then output the current to the movable coil <NUM> and the stationary coil <NUM>.

<FIG> is a schematic diagram of a circuit breaker <NUM> according to another embodiment of this application. Optionally, as shown in <FIG>, the circuit breaker <NUM> may further include a solid-state switch circuit <NUM>, and the solid-state switch circuit <NUM> and the mechanical switch circuit <NUM> are connected in parallel with each other. When the circuit breaker <NUM> is turned on, the solid-state switch circuit <NUM> is conducted prior to the mechanical switch circuit <NUM>, and when the solid-state switch circuit <NUM> is disconnected, the mechanical switch circuit <NUM> is disconnected prior to the solid-state switch circuit <NUM>.

In this embodiment of this application, the circuit breaker <NUM> uses a form in which the mechanical switch circuit <NUM> is connected in parallel to the solid-state switch circuit <NUM>, and the solid-state switch circuit <NUM> can avoid an electric arc generated in the contact when the mechanical switch circuit <NUM> is conducted or disconnected, thereby shortening arcing time, improving a switching speed of the circuit breaker <NUM>, and prolonging a service life of the mechanical switch circuit <NUM>.

Optionally, a specific structure of the solid-state switch circuit <NUM> is not limited in this embodiment of this application, provided that the solid-state switch circuit <NUM> can implement a function of the solid-state switch circuit <NUM>. For example, a specific example of the solid-state switch circuit <NUM> is described below with reference to <FIG>.

<FIG> is a schematic diagram of a structure of a solid-state switch circuit <NUM> according to an embodiment of this application. As shown in <FIG>, the solid-state switch circuit <NUM> includes a main switch circuit <NUM>, a snubber circuit <NUM>, and a buffer circuit <NUM>.

The main switch circuit <NUM> includes diodes D1 to D4, and a switching transistor K1. The switching transistor K1 may be an IGBT, an integrated gate-commutated thyristor (integrated gate-commutated thyristor, IGCT), an MOS, or a BJT, or may be switching component of another type.

As shown in <FIG>, a first end of the solid-state switch circuit <NUM> is connected to an anode of the diode D1 and a cathode of the diode D2, and a second end of the solid-state switch circuit <NUM> is connected to an anode of the diode D3 and a cathode of the diode D4. A cathode of the diode D1 and a cathode of the diode D3 are connected to a first end of the switching transistor K1, and an anode of the diode D2 and an anode of the diode D4 are connected to a second end of the switching transistor K1.

If the switching transistor K1 is the IGBT, the first end of the switching transistor K1 is a collector of the IGBT, and the second end of the switching transistor K1 is an emitter of the IGBT.

The main switch circuit <NUM> is configured to control the solid-state switch circuit <NUM> by controlling turn-on and turn-off of the switching transistor K1, and the main switch circuit <NUM> can implement a bidirectional control function.

<FIG> and <FIG> are respectively schematic diagrams of conduction of a solid-state switch circuit <NUM> in different current directions. As shown in <FIG>, the diode D1, the switching transistor K1, and the diode D4 may implement a current path in one direction. As shown in <FIG>, the diode D3, the switching transistor K1, and the diode D4 may implement a current path in another direction.

The snubber circuit <NUM> may be configured to absorb energy when the switching transistor K1 is turned off. The snubber circuit <NUM> typically includes a varistor. The varistor can be connected in parallel in the circuit. When the circuit is in normal use, an impedance of the varistor is very high and a leakage current is very small, which can be regarded as an open circuit and has little impact on the circuit. However, when a very high suddenly changed voltage arrives, a resistance value of the varistor drops instantly, allowing a large current to flow through the varistor and clamp the overvoltage to a specific value.

The buffer circuit <NUM> is configured to protect the switching transistor K1 from being damaged due to the overvoltage when the switching transistor K1 is turned off, and reduce a turn-off loss of the switching transistor K1. A specific structure of the buffer circuit <NUM> is not limited in this application, provided that the buffer circuit <NUM> can implement the foregoing functions. Optionally, the solid-state switch circuit <NUM> may not include the buffer circuit <NUM>.

The following describes a structure of the mechanical switch circuit <NUM> in embodiments of this application with reference to the accompanying drawings. <FIG> is a three-dimensional schematic diagram of a sectional view of a mechanical switch circuit <NUM> according to an embodiment of this application. As shown in <FIG>, the mechanical switch circuit <NUM> includes a busbar <NUM>, a power module (not marked in the figure), and a drive module (not marked in the figure).

The power module includes a movable contact <NUM> and a stationary contact <NUM>. The stationary contact <NUM> is electrically connected to the busbar <NUM>, the movable contact <NUM> is movable, when the movable contact <NUM> is in contact with the stationary contact <NUM>, the mechanical switch circuit <NUM> is conducted, and when the movable contact <NUM> is disconnected from the stationary contact <NUM>, the mechanical switch circuit <NUM> is disconnected.

The drive module includes a movable coil <NUM> and a stationary coil <NUM>. The movable coil <NUM> and the stationary coil <NUM> are placed adjacently, so that the movable coil <NUM> and the stationary coil <NUM> repel or attract each other based on whether current directions are the same, and the movable coil <NUM> is configured to drive the movable contact <NUM> to be in contact with or disconnected from the stationary contact <NUM>.

It can be learned from <FIG> that, the busbar <NUM> includes two parts that are not connected to each other, which may be respectively referred to as a first busbar <NUM>-<NUM> and a second busbar <NUM>-<NUM>, and the stationary contact <NUM> includes a first stationary contact <NUM>-<NUM> and a second stationary contact <NUM>-<NUM> (refer to <FIG>). The first stationary contact <NUM>-<NUM> is connected to the first busbar <NUM>-<NUM>, and the second stationary contact <NUM>-<NUM> is connected to the second busbar <NUM>-<NUM>. The first stationary contact <NUM>-<NUM> and the second stationary contact <NUM>-<NUM> are in an electrically disconnected state. Therefore, when the stationary contact <NUM> is disconnected from the movable contact <NUM>, the first busbar <NUM>-<NUM> and the second busbar <NUM>-<NUM> are in an electrically disconnected state, that is, the mechanical switch circuit <NUM> is in a disconnected state. When the stationary contact <NUM> is in contact with the movable contact <NUM>, the movable contact <NUM> connects the first stationary contact <NUM>-<NUM> and the second stationary contact <NUM>-<NUM> to provide a low-resistance path between the first busbar <NUM>-<NUM> and the second busbar <NUM>-<NUM>, so that the first busbar <NUM>-<NUM> is electrically connected to the second busbar <NUM>-<NUM>, that is, the mechanical switch circuit <NUM> is in a conducting state.

As shown in <FIG>, in some examples, the movable coil <NUM> is coaxial with the movable contact <NUM>, and the movable coil <NUM> can drive the movable contact <NUM> to move up and down in an axial direction. Further, the stationary coil <NUM> is coaxial with the movable coil <NUM>.

<FIG> is a schematic diagram of a cross section of a mechanical switch circuit <NUM> in a conducting state according to an embodiment of this application. As shown in <FIG>, the movable coil <NUM> and the stationary coil <NUM> approach each other and are placed side by side. When the mechanical switch circuit <NUM> is in the conducting state, the current directions of the movable coil <NUM> and the stationary coil <NUM> are opposite, the movable coil <NUM> approaches the stationary coil <NUM>, and drives the movable contact <NUM> to be in contact with the stationary contact <NUM>, so that the mechanical switch circuit <NUM> is conducted. Fcontact in <FIG> indicates downward attraction force applied to the movable coil <NUM> and the movable contact <NUM>.

Optionally, a maintenance apparatus is further disposed in the mechanical switch circuit <NUM>. The maintenance apparatus may be configured to maintain the movable contact <NUM> and the stationary contact <NUM> in a contact state after the movable contact <NUM> is in contact with the stationary contact <NUM>, and to maintain the movable contact <NUM> and the stationary contact <NUM> in a disconnected state after the movable contact <NUM> is disconnected from the stationary contact <NUM>. For example, the maintenance apparatus in <FIG> is an electromagnet, and attraction force (Fmagnet) generated by the electromagnet can keep the movable contact <NUM> and the stationary contact <NUM> in the contact state. It should be understood that the maintenance apparatus is merely used as an example, and the maintenance apparatus may alternatively use another implementation. In some examples, the maintenance apparatus may alternatively be implemented by using a mechanical structure such as a buckle. This is not limited in this embodiment of this application.

<FIG> is a schematic diagram of a cross section of a mechanical switch circuit <NUM> in a conducting state according to an embodiment of this application. As shown in <FIG>, when the mechanical switch circuit <NUM> is in the conducting state, the current directions of the movable coil <NUM> and the stationary coil <NUM> are the same, the movable coil <NUM> stays away from the stationary coil <NUM>, and drives the movable contact <NUM> to be disconnected from the stationary contact <NUM>, so that the mechanical switch circuit <NUM> is conducted. Fopen in <FIG> indicates upward repulsion force applied to the movable coil <NUM> and the movable contact <NUM>.

According to the invention, a wound coil of the movable coil <NUM> uses a first conductive material, a wound coil of the stationary coil <NUM> uses a second conductive material, and a density of the first conductive material is less than a density of the second conductive material. For example, the conductive material of the movable coil <NUM> may be aluminum, and the conductive material of the stationary coil <NUM> may be copper.

According to the invention, the wound coil of the movable coil <NUM> uses the conductive material with the low density, to reduce quality of the movable coil <NUM>, and further reduce energy required when the movable coil <NUM> moves, to save power of the mechanical switch circuit <NUM>.

For another example, a cross section of the movable coil <NUM> may be smaller than a cross section of the stationary coil <NUM>, so that the quality of the movable coil <NUM> is smaller than quality of the stationary coil <NUM>.

<FIG> is a top view of a movable coil <NUM> according to an embodiment of this application. As shown in <FIG>, the wound coil of the movable coil <NUM> can be led out by a flexible conducting wire, so that an armature system can move automatically without damage.

<FIG> is a schematic diagram of structures of a movable contact <NUM> and a stationary contact <NUM> according to an embodiment of this application. The stationary contact includes the first stationary contact <NUM>-<NUM> and the second stationary contact <NUM>-<NUM>. As shown in <FIG>, the movable contact <NUM> is configured to ensure that when a movable contact system is closed, the stationary contacts <NUM> located on two sides are connected and provide the low-resistance path. When the armature system is activated, the movable coil <NUM> moves upward in the axial direction of the movable coil <NUM>, thus driving the movable contact <NUM> to move together. It should be noted that a switching speed of the mechanical switch circuit <NUM> is related to a distance between the movable coil <NUM> and the stationary coil <NUM>. Disconnection of the mechanical switch circuit <NUM> is used as an example. A longer distance between the two coils indicates longer delay time for the mechanical switch circuit <NUM> to start separation from the contact. Therefore, a faster separation speed of the movable contact <NUM> can be implemented by reducing the distance between the two coils, so that the switching speed of the mechanical switch circuit <NUM> can be increased, for example, a switching speed of several hundred µs (microseconds) can be implemented.

As shown in <FIG>, in some examples, a protrusion part is disposed along a first surface of the movable contact <NUM>, to ensure a reliable connection of the movable and stationary contacts, thereby improving switching sensitivity of the mechanical switch circuit <NUM>. The first surface of the movable contact <NUM> is configured to be in contact with the stationary contact <NUM>.

Terms such as "component", "module", and "system" used in this specification are used to indicate computer-related entities, hardware, firmware, combinations of hardware and software, software, or software being executed. For example, a component may be, but is not limited to, a process that runs on a processor, a processor, an object, an executable file, an execution thread, a program, and/or a computer. As shown by using figures, both a computing device and an application that runs on the computing device may be components. One or more components may reside within a process and/or an execution thread, and a component may be located on one computer and/or distributed between two or more computers. In addition, these components may be executed from various computer-readable media that store various data structures. For example, the components may communicate by using a local and/or remote process and based on, for example, a signal having one or more data packets (for example, data from two components interacting with another component in a local system, a distributed system, and/or across a network such as the internet interacting with other systems by using the signal).

A person of ordinary skill in the art may be aware that units and algorithm steps described with reference to embodiments disclosed in this specification can be implemented by electronic hardware, or a combination of computer software and electronic hardware. A person skilled in the art may use different methods to implement the described functions for each particular application, but it should not be considered that the implementation goes beyond the scope of this application, which is defined by the appended claims.

For example, division into the units is merely logical function division and may be other division in an actual implementation. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections may be implemented through some interfaces.

The units described as separate components may or may not be physically separate, and components displayed as units may or may not be physical units, may be located in one position, or may be distributed on a plurality of network units.

When the functions are implemented in the form of a software functional unit and sold or used as an independent product, the functions may be stored in a computer-readable storage medium. Based on such an understanding, the technical solutions of this application essentially, or the part contributing to the conventional technology, or some of the technical solutions may be implemented in a form of a software product. The computer software product is stored in a storage medium, and includes several instructions for instructing a computer device (which may be a personal computer, a server, or a network device) to perform all or some of the steps of the methods described in embodiments of this application. The storage medium includes any medium that can store program code, such as a USB flash drive, a removable hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk, or an optical disc.

Claim 1:
A circuit breaker(<NUM>), comprising a mechanical switch circuit(<NUM>), wherein the mechanical switch circuit(<NUM>) comprises:
a busbar(<NUM>);
a power module(<NUM>), comprising a movable contact(<NUM>) and a stationary contact(<NUM>), wherein the stationary contact(<NUM>) is electrically connected to the busbar(<NUM>), the movable contact(<NUM>) is movable, when the movable contact(<NUM>) is in contact with the stationary contact(<NUM>), the mechanical switch circuit(<NUM>) is conducted, and when the movable contact(<NUM>) is disconnected from the stationary contact(<NUM>), the mechanical switch circuit(<NUM>) is disconnected; and
a drive module(<NUM>), comprising a movable coil(<NUM>) and a stationary coil(<NUM>), wherein the movable coil(<NUM>) and the stationary coil(<NUM>) are placed adjacently, so that the movable coil(<NUM>) and the stationary coil(<NUM>) repel or attract each other based on whether current directions are the same, and the movable coil(<NUM>) is configured to drive the movable contact(<NUM>) to be in contact with or disconnected from the stationary contact(<NUM>);
characterised in that a wound coil of the movable coil(<NUM>) uses a first conductive material, a wound coil of the stationary coil(<NUM>) uses a second conductive material, and a density of the first conductive material is less than a density of the second conductive material.