EP4677633A1

EP4677633A1 - Switch for use in a hybrid circuit breaker

Info

Publication number: EP4677633A1
Application number: EP24712404.3A
Authority: EP
Inventors: Tanmay Pralhad TAMBOLI; Rushikesh Bhagvat SOLASE; Matthias KATZENSTEINER
Original assignee: Eaton Intelligent Power Ltd
Current assignee: Eaton Intelligent Power Ltd
Priority date: 2023-03-22
Filing date: 2024-03-07
Publication date: 2026-01-14
Also published as: WO2024193853A1

Abstract

Described herein is an electromechanical bypass switch (100, 200) for use in a hybrid circuit breaker, a hybrid circuit breaker comprising the switch, and a method of operating the switch. The electromechanical bypass switch comprises a housing (120, 220) with a top portion (122, 222) and a bottom portion (124, 224). The top portion and the bottom portion of the housing are hermetically sealed together. The switch also comprises a contact system (130, 230) arranged within the housing with a fixed contact (134, 234) disposed in the bottom portion of the housing and a moveable contact. The switch also comprises an electromagnetic actuator arranged within the housing and configured to open and close a current conduction path (110, 210) through the switch by actuating the moveable contact. The switch may optionally also comprise a resilient member configured to urge the moveable contact into a first position. When a current is applied to a voice coil (142) of the electromagnetic actuator disposed in the top portion of the housing, the electromagnetic actuator is configured to cause the moveable contact to move from the first position to a second position. In one of the first and second positions, the moveable contact is electrically connected to the fixed contact to close the current conduction path. In the other of the first and second positions, the moveable contact is electrically separate from the fixed contact to open the current conduction path.

Description

Switch for use in a hybrid circuit breaker

Field

This relates to a switch for use in a hybrid circuit breaker. In particular, this relates to an electromechanical bypass switch or other switch including an electrical switching mechanism. The switch has a movable contact for opening and closing a current conduction path and is provided with a hermetically sealed housing. A hybrid circuit breaker which incorporates the switch is also described herein, along with a method of operating the switch.

Background

A current conduction path can be defined along a current line and through a switch (or switching mechanism). The switch can be electrically connected to the current line by way of, for example, electrical contacts or terminals. Such switches can use a switching mechanism to open and close the current conduction path. One approach is to use an electromechanical bypass switch with a vacuum interrupter comprising a fixed contact and a moveable contact. The moveable contact can move between a position where it is electrically connected to the fixed contact (to close the current conduction path through the switch) and a position where it is electrically separate from the fixed contact (to open the current conduction path through the switch).

It is desirable to provide an improved electromechanical bypass switch which is compact, robust, and long-lasting. Such an improved switch is desirable for use in, for example, hybrid circuit breaker devices, which have applications in power transmission, industrial machinery, and control panels.

Summary

Described herein is an electromechanical bypass switch for use in a hybrid circuit breaker, a hybrid circuit breaker comprising the switch, and a method of operating the switch.

In a first aspect, an electromechanical bypass switch is provided as defined in the first appended independent apparatus claim, with optional features defined in the dependent claims appended thereto. In a second aspect, a hybrid circuit breaker comprising said electromechanical bypass switch is provided as defined in the second appended independent apparatus claim, with optional features defined in the dependent claims appended thereto. In a third aspect, a method of operating the switch of the first aspect is provided as defined the appended independent method claim. Any features described in relation to one particular aspect maybe implemented as part of another aspect.

Described herein, in a first aspect of the specification, is an electromechanical bypass switch for use in a hybrid circuit breaker. The electromechanical bypass switch (also referred to herein simply as a switch) is configured for connection to a current line of the hybrid circuit breaker. The switch comprises a housing with a top portion and a bottom portion. The top portion and the bottom portion of the housing are hermetically sealed together. The switch also comprises a contact system arranged within the hermetically sealed housing. The contact system comprises a moveable contact electrically connected to a first portion of the current line, and a fixed contact disposed in the bottom portion of the housing and electrically connected to a second portion of the current line. The switch also comprises an electromagnetic actuator arranged within the hermetically sealed housing and configured to open and close a current conduction path defined along the current line and through the electromechanical bypass switch by actuating the moveable contact of the contact system along a first axis of the electromagnetic actuator. The electromagnetic actuator comprises a voice coil disposed in the top portion of the housing. When a current is applied to the voice coil, the electromagnetic actuator is configured to cause the moveable contact to move along the first axis from a first position to a second position. The moveable contact is electrically connected to the fixed contact in one of the first and second positions to close the current conduction path along the current line, and is electrically separate from the fixed contact in the other of the first and second positions to open the current conduction path along the current line.

In some examples, the switch also comprises a resilient member configured to urge the moveable contact along the first axis and into the first position. The resilient member is understood to be resiliently deformable through form and/ or material. The resilient member can apply a closing force to the moveable contact, minimising or preventing accidental opening of the switch in response to an impact or vibration. A more robust switch may therefore be provided. Optionally, the resilient member is a spring. Springs maybe cheap to purchase and/or manufacture. The switch described herein can provide rapid and reliable opening and closing of a current conduction path in a highly compact physical footprint. The switch has a housing, and arranged within this housing, the switch includes (amongst other components) a contact system and an electromagnetic actuator. The electromagnetic actuator has a voice coil which is contained in a top portion of the housing, and the contact system has a fixed contact which is contained in a bottom portion of the housing. In other words, the top portion of the housing houses at least part of the electromagnetic actuator, and the bottom portion of the housing houses at least part of the contact system. By hermetically sealing the top portion and bottom portion of the housing together to create a hermetically sealed housing, the overall size of the housing needed for the switch maybe reduced, and a compact switch maybe provided.

The size of a hybrid circuit breaker can be limited by, for example, the requirement for it to be able to interface with external terminals, connectors, or circuits with standard dimensions. The layout of circuitry and components within a hybrid circuit breaker can be dictated primarily by safety requirements and standards, which can involve providing maximal physical separation between different current paths, for instance. In this context, it is desirable to provide a highly compact electromechanical bypass switch for use in a hybrid circuit breaker (such as the switch with hermetically sealed housing described herein), such that it is possible to provide a hybrid circuit breaker with an efficient layout and improved safety for a given overall size.

By using a hermetically sealed housing, the switch can also prevent external contamination from damaging or degrading the components of the switch. The hermetic seal can prevent substantially all small particles (e.g., dust) and gases (e.g., reactive gases) from entering the switch housing. This may help to prevent the mechanical action of the electromagnetic actuator, contact system, and optionally the resilient member, from being impeded or damaged, and thus increase the longevity of the switch (and/or hybrid circuit breaker).

Typical switches or switching mechanisms which use a vacuum interrupter in combination with an electromagnetic actuator can be built in a modular manner, with separate housings for the vacuum interrupter portion and the electromagnetic actuator portion, for example. Using this arrangement may necessitate the inclusion of several further components to align the vacuum interrupter and electromagnetic actuator (increasing manufacturing complexity), as well as increasing the overall size of the switch for a given size of components. For example, this arrangement may require one or more coupling components to connect various parts of the switch together. This arrangement may also result in gaps between parts of the switch into which external contamination can enter, potentially reducing the lifetime of the switch. Unlike such a modular switch, the switch with contact system and electromagnetic actuator within a single hermetically sealed housing described herein maybe more compact, robust, and long -lasting (longer lifetime). Moreover, any contact system (not just a vacuum interrupter) can be used in combination with the electromagnetic actuator. Optionally, the moveable contact is electrically connected to the fixed contact in the first position and is electrically separate from the fixed contact in second position. This arrangement may provide a switch which is normally closed (allowing current to flow along the current conduction path through the switch) in its normal state (with the optional resilient member urging the moveable contact into the first position), and where the current applied to the voice coil causes the current conduction path to be opened (with the moveable contact moving along the first axis from the first position to the second position). By arranging the fixed and moveable contacts in this manner, a switch suitable for rapidly opening a circuit can be provided, allowing the switch to safely remove power supply from faulty or damaged equipment connected to it, for example.

Optionally, the top portion of the housing is formed from a magnetic material.

Optionally, the magnetic material is a magnetic steel. Magnetic steels maybe durable and cheap to purchase and/or manufacture. This approach can consolidate or reduce the number of components by integrating operational features of the electromagnetic actuator with the switch housing.

Optionally, the electromagnetic actuator further comprises the following components disposed in the top portion of the housing: a magnetic core; one or more permanent magnets at least partially enclosing the magnetic core; and a bobbin at least partially enclosing the magnetic core, wherein the voice coil is wound on the bobbin. The voice coil can be wound around an exterior of the bobbin, with the magnetic core partially enclosed in an interior of the bobbin. Optionally, the top portion of the housing, the magnetic core, the one or more permanent magnets, the bobbin, and the voice coil are arranged such that they interact to form a magnetic field that drives the moveable contact from the first position to the second position when the current is applied to the voice coil.

This arrangement may provide an electromagnetic actuator which efficiently guides a magnetic field of sufficient strength to rapidly move the moveable contact (which may comprise one or more magnetic portions) from the first position to the second position when the current is applied to the voice coil. By forming the top portion of the housing from a magnetic material, the top portion of the housing may contribute to guiding the magnetic field (as described above) whilst also providing at least part of the hermetically sealed housing which prevents external contamination from damaging or degrading the components of the switch. When the top portion of the hermetically sealed housing is formed from a magnetic material, no further magnetic materials (for the electromagnetic actuator) or housing/sealing materials maybe needed, thus reducing the overall size of the switch.

Optionally, the moveable contact is arranged in the bottom portion of the housing and is integrated with the bobbin. By integrating the moveable contact with the bobbin, the moveable contact may be able to extend at least partially into the top portion of the housing as well as the bottom portion of the housing. This may facilitate an efficient layout of components within the housing (such as placing the optional resilient member in the top portion of the housing), again reducing the overall size of the switch.

Optionally, the bottom portion of the housing is formed from a ceramic material. The ceramic material may act as an electrical insulator, providing electrical isolation for the contact system. This electrical isolation may help to reduce the chance of short circuiting or electrical interference with any electrical components exterior to the switch (such as those belonging to the hybrid circuit breaker).

Optionally, the bottom portion of the housing comprises a chamber surrounding the contact system. In some examples, the chamber contains a vacuum. In other examples, the chamber contains an inert gas. The vacuum or inert gas medium in the chamber may facilitate quick extinguishing of arcing between the moveable and fixed contacts as the moveable contact is moved between the first position and the second position. A safer switch may therefore be provided. Optionally, the hermetic seal between the top and bottom portions of the housing is formed by brazing the top and bottom portions of the housing together. The top and bottom portions of the housing may be produced separately (and optionally manufactured of different materials, e.g., ceramic and magnetic steel) and brazed together, providing a cheap and simple modular manufacturing process. A brazed joint may provide a hermetic seal between the top and bottom portions of the housing whilst minimising any thermal distortion of the two portions of the housing.

Optionally, the moveable contact is electrically connected to the first portion of the current line by a flexible conductor. By using a flexible conductor with sufficient length and compliancy (e.g. a flexible conductor which is not held taut when the moveable contact is in either the first position or the second position) to transfer current from (i.e. electrically connect) the first portion of the current line, the moveable contact may be permitted to move freely between the first and second position without any resistance from the flexible conductor attached to it, and without any strain being induced in the flexible conductor. This can further increase the reliability and longevity of the switch. Optionally, the flexible conductor is a flexible copper braid. Using a copper braid may provide a flexible conductor with low resistance, such that a current can flow along the flexible conductor with minimal heating.

Optionally, the flexible conductor extends from the housing, and a hermetic seal is formed around the flexible conductor by brazing. This arrangement may permit the switch to be connected to an external circuit (for example, as part of a hybrid circuit breaker). Brazing around the flexible conductor may again provide a cheap and simple process for creating a hermetically sealed housing.

Optionally, the top portion of the housing further comprises a bellows seal, and the electromagnetic actuator comprises an upper portion extending through the bellows seal. Using a bellows seal may allow the housing to remain hermetically sealed, whilst also facilitating further components of the switch (e.g., which are configured to interact with the upper portion of the electromagnetic actuator extending through the bellows seal) to be located outside the densely populated housing, reducing the overall size required for the switch. Optionally, the switch further comprises a mechanical latch disposed exterior to the housing and configured to fixedly retain the upper portion of the electromagnetic actuator when the moveable contact is in the second position. When the moveable contact is moved from the first position to the second position, it is desirable to retain it in the second position such that, for example, the current conduction path through the switch remains open, and faulty or damaged equipment connected to the switch remains electrically isolated from its power source. This arrangement allows the current applied to the voice coil to be removed shortly after the moveable contact has moved from the first position to the second position (i.e., the current applied to the voice coil can thus be very short in duration), with the mechanical latch retaining the upper portion of the electromagnetic actuator in place by mechanical means rather than electromagnetic means. This can provide a switch with reduced power requirements for operation.

Optionally, a mechanical latch is configured to fixedly retain an upper portion of the electromagnetic actuator when the moveable contact is in the second position. This arrangement allows the current applied to the voice coil to be removed shortly after the moveable contact has moved from the first position to the second position (i.e., the current applied to the voice coil can thus be very short in duration), with the mechanical latch retaining the upper portion of the electromagnetic actuator in place by mechanical means rather than electromagnetic means. This can provide a switch with reduced power requirements for operation. The mechanical latch can be disposed exterior to the housing, wherein the top portion of the housing further comprises a bellows seal, the upper portion of the electromagnetic actuator extending through the bellows seal. This allows the upper portion of the electromagnetic actuator to be located outside the densely populated housing, reducing the overall size required for the switch. Alternatively, the mechanical latch can be disposed interior to the housing.

This arrangement may increase a size of the housing, but it obviates the need for the bellows seal around the moveable upper portion. It will be understood that, when the latch is interior to the housing, a reset mechanism may need to be provided outside of and extending into the housing. One or more seals can be provided around said reset mechanism to maintain the hermetic sealing within the housing.

In some examples, the mechanical latch comprises a spring-operated arm portion configured to interact with a notch in the upper portion of the electromagnetic actuator to fixedly retain the upper portion. In other examples, the latch comprises two resiliently deformable members (optionally two compression springs) disposed either side of the upper portion and each pivotably coupled or mounted at one (a first) end to the upper portion, wherein an opposite (second) end of each resiliency deformable member is fixed. The fixed ends can be fixed to the housing (when the latch is disposed within the housing) or to another component surrounding or proximate to the switch (when the latch is external to the housing).

Optionally, the current applied to the voice coil is provided by one or more capacitors.

By using capacitor(s) to apply the current to the voice coil, a high current maybe provided over a very short period of time, allowing the electromagnetic actuator to very quickly move the moveable contact of the contact system from the first position to the second position, facilitating rapid circuit switching.

Optionally, the moveable contact and the fixed contact are formed from metal.

Optionally, the metal is copper. Using copper may provide fixed and moveable contacts with low resistance, such that a current can flow between the two contacts with minimal heating.

In a second aspect of the specification, a hybrid circuit breaker is provided. The hybrid circuit breaker comprises an input connector configured to be connected to a power grid. The hybrid circuit breaker also comprises an output connector configured to be connected to a load. The hybrid circuit breaker also comprises a current path connecting the input connector and the output connector. The hybrid circuit breaker also comprises the electromechanical bypass switch of the first aspect as described above, arranged in the current path. The hybrid circuit breaker also comprises a semiconductor circuit in parallel with the electro-mechanical bypass switch. The hybrid circuit breaker also comprises a control unit being capable of controlling a commutation, from the current path in which the electromechanical bypass switch is arranged and to the semiconductor circuit, in case of a switch-off operation.

Optionally, the hybrid circuit breaker further comprises one or more capacitor banks to provide the current applied to the voice coil. Using one or more banks of capacitors may facilitate a large current being applied to the voice coil in a short period of time, permitting faster switching.

Optionally, the one or more capacitor banks comprise a first capacitor bank and a second capacitor bank, and the first capacitor bank has a higher capacity than the second capacitor bank. This may allow at least two different switching speeds to be provided by the switch which could, for example, be selected depending on the power and safety requirements of particular situation in which the hybrid circuit breaker is used. Optionally, the one or more capacitor banks are part of the control unit. This arrangement may reduce the number of components required for the hybrid circuit breaker as well as reducing its overall size.

In a third aspect of the specification, a method of operating the electromechanical bypass switch of the first aspect is provided. The method comprises: applying the current to the voice coil; and in response to the application of the current to the voice coil, moving, by the electromagnetic actuator, the moveable contact along the first axis from the first position to the second position. Optionally, the method further comprises fixedly retaining, by the mechanical latch, the upper portion of the electromagnetic actuator when the moveable contact is in the second position.

Optionally, the method further comprises: subsequent to fixedly retaining the upper portion of the electromagnetic actuator, removing the current from the voice coil; manually releasing the mechanical latch; and in response to the manual release of the mechanical latch, urging, by the resilient member, the moveable contact along the first axis from the second position to the first position. It will be understood that any of the features described above with reference to the first and second aspects may be provided in any suitable combination. Moreover, any such features may be combined with any features of the method of the third aspect, or vice versa, as appropriate. Brief Description of the Drawings

The following description is with reference to the following Figures.

Figure 1: Figure 1A shows a schematic cross section of an electromechanical bypass switch in accordance with an example of the first aspect, where a moveable contact is in a first position and a current conduction path (defined along a current line and through the switch) is closed, and Figure 1B shows a schematic cross section of the electromechanical bypass switch of Figure 1A, where the moveable contact is in a second position and the current conduction path is open, such that no current flows through the switch.

Figure 2: Figure 2A shows a cross section of an example electromechanical bypass switch, where the moveable contact is in the first position and the current conduction path is closed, and Figure 2B shows a cross section of the example electromechanical bypass switch of Figure 2A, where the moveable contact is in the second position and the current conduction path is open, such that no current flows through the switch.

Figure 3: Figure 3A shows a cross section of a first example mechanical latch, Figure 3B shows a cross section of a second example mechanical latch when the moveable contact is in the first position and the current conduction path is closed, and Figure 3C shows a cross section of the second example mechanical latch when the moveable contact is in the second position and the current conduction path is open.

Figure 4 shows a block diagram of a hybrid circuit breaker in accordance with an example of the second aspect, the hybrid circuit breaker comprising an example electromechanical bypass switch.

Figure 5 illustrates a method in accordance with the third aspect.

Detailed Description With reference to Figure 1 (Figures 1A and 1B), an electromechanical bypass switch too for use in a hybrid circuit breaker is described. In the following description, the terms “electromechanical bypass switch” and “switch” are used, but the features described herein may be implemented in any other device with an electrical switching mechanism or action (such as a contactor, breaker, relay, or electrical isolation device). The switch too is configured for connection to a current line of the hybrid circuit breaker.

A current conduction path 110 is defined along the current line and through the electromechanical bypass switch too. In Figure 1, only the portion of current conduction path 110 through the switch too is shown. The switch may comprise a plurality of components and/ or structures which interact to open and close the current conduction path 110. An electromagnetic actuator 140 maybe a subset of these components. A contact system 130, a resilient member 160, and a housing 120 may also be a subset of these components. A schematic view of these components of the switch is shown in Figure 1. The electromechanical bypass switch too comprises a housing 120. The housing 120 may enclose or partially enclose the switch too, i.e., it may contain all of or a subset of the components of the switch. The housing may comprise a cavity into which the components of the switch may fit or may be disposed. The housing may be arranged to retain some or all of the components of the switch. For example, one or more components of the switch (i.e., the electromagnetic actuator 140, the contact system 130, or the resilient member 160) and the housing maybe mechanically or chemically coupled or joined or bonded to or otherwise attached/ connected together. Alternatively or additionally, one or more components of the switch (i.e., the electromagnetic actuator, the contact system, or the resilient member) may interlock together.

The housing 120 comprises a top portion 122 and a bottom portion 124. One or more components of the switch maybe disposed in the top portion of the housing and one or more other components of the switch maybe disposed in the bottom portion of the housing. Additionally, one or more components of the switch may be disposed such that they at least partially extend into the top portion of the housing and at least partially extend into the bottom portion of the housing. Other components of the switch may be disposed wholly or partially exterior to the housing. The top portion of the housing 122 and the bottom portion of the housing 124 are hermetically sealed together. As used herein, the term ‘hermetic seal’ refers to any type of joint or seal that wholly or substantially prevents the passage of air and other gases. Put another way, the top portion of the housing and the bottom portion of the housing are joined together in such a way that an airtight, hermetic seal is formed at the joint between the two portions. The top and bottom portions of the housing are also formed such that, once the top and bottom portions of the housing are hermetically sealed together, the overall housing 120 itself is hermetically sealed. In other words, the exterior sides of the housing (the sides of the housing which remain exposed once the top portion and the bottom portion of the housing have been hermetically sealed together) are themselves airtight.

Hermetically sealing the top portion of the housing 122 (which contains one or more components of the switch) to the bottom portion of the housing 124 (which contains one or more other components of the switch) means that the overall size of the housing 120 is reduced as much as possible, providing a highly compact switch too. The hermetically sealed housing 120 can also prevent any external contaminants (such as chemically reactive gases or small particles like dust or dirt) from entering the switch too. This can prevent the switch being damaged by chemical decay or physical blockages, which may increase the lifetime of the switch (and/or the interval needed between routine maintenance and repair).

The top and bottom portions of the housing 122, 124 may be formed from any suitable materials which can provide airtight exterior sides and can allow the top and bottom portions of the housing to be hermetically sealed together. The top and bottom portions of the housing may be formed from the same material or may be formed from different materials. In some examples, the top portion of the housing 122 may be formed wholly or substantially from a metal. Specifically, the top portion of the housing maybe formed from a magnetic metal, such as a magnetic steel. Forming the top portion of the housing from a magnetic material may have particular advantages which are explained below in relation to the electromagnetic actuator 140. In some examples, the bottom portion of the housing 124 may be formed wholly or substantially from a ceramic material. Ceramic materials are good electrical insulators, and so using a ceramic material for the bottom portion of the housing may provide effective electrical isolation between electrical components disposed in the bottom portion of the housing 124 and electrical components exterior to the housing 120 (such as electrical components forming part of a hybrid circuit breaker). This can help prevent the switch (and/or hybrid circuit breaker) failing due to electrical interference or short circuiting.

The top portion and the bottom portion of the housing 122, 124 may be joined together at a substantially flat surface. This may facilitate the formation of a strong and robust hermetic seal. For example, a lower (flat) surface of the top portion of the housing 122 maybe sealed to an upper (flat) surface of the bottom portion of the housing 124. The top and bottom portions of the housing may be joined together using any suitable joining process, such as welding, soldering, or brazing. In some examples (such as, but not limited to, when the top portion of the housing 122 is formed from a metal and the bottom portion of the housing 124 is formed from a ceramic material), the hermetic seal between the top and bottom portions of the housing 122, 124 may be formed by brazing the top and bottom portions of the housing together. Brazing is a joining process whereby two surfaces can be bonded together by melting a filler metal and flowing the filler metal into the joint between the two surfaces. By choosing a filler metal with a lower melting temperature than the surrounding materials (in the example above, ceramic and metal), a strong joint can be created with minimal thermal distortion of the top and bottom portions of the housing 122, 124. The melted filler metal runs through the gaps between the top and bottom portions of the housing to create a robust hermetic seal. Any suitable filler material and brazing process (in the example above, a ceramic-to-metal brazing process) can be used. In some examples where a ceramic surface is to be brazed, the brazing process may involve first metallising the ceramic surface. Brazing the top and bottom portions of the housing together may allow a strong and resilient hermetic seal to be formed between the two portions whilst minimising any thermal distortion or damage (due to the low temperatures used) to the housing during manufacturing.

The electromechanical bypass switch too comprises a contact system 130. The contact system 130 is arranged within the hermetically sealed housing 120, i.e., the hermetically sealed housing may enclose or partially enclose the contact system. As used herein, the term “contact system” refers to at least two electrical contacts which can be electrically connected or electrically separated. Any suitable contact system may be used. The contact system can be surrounded by any medium suitable for rapidly extinguishing electric discharges between the at least two electrical contacts, said medium being disposed within the hermetically sealed housing. When the at least two electrical contacts are electrically connected and have a current flowing through them, the at least two electrical contacts may then be separated. Particularly at high currents and high voltages, this can cause a transient electrical discharge or arc to form between the separated electrical contacts. It will be understood that it is desirable to extinguish this discharge or arc as quickly as possible in switching applications. The medium surrounding the at least two electrical contacts may be specifically chosen to improve the extinguishing or quenching properties of the contact system 130. The medium may be a vacuum, or an inert fluid, optionally an inert gas.

The contact system 130 has a moveable contact 132 (i.e., an electrically conductive contact which is configured to move or to be moved) disposed within the housing 120.

The moveable contact 132 may be disposed in the bottom portion of the housing 124 or it may be disposed in the top portion of the housing 122, or it may at least partially extend into the bottom portion of the housing 124 and at least partially extend into the top portion of the housing 122. The moveable contact 132 is electrically connected to a first portion of the current line 110A. The first portion of the current line 110A may be disposed exterior to the switch housing 120, and the moveable contact may be electrically coupled to the first portion of the current line by any suitable means. The moveable contact may be formed from metal. For example, the moveable contact may be formed from copper. Using copper may provide a moveable contact with low resistance, such that a current can flow through the moveable conductor with minimal heating.

In one example, the moveable contact 132 may be coupled to a flexible conductor, where the flexible conductor is coupled to the first portion of the current line 110A. The flexible conductor may partially or wholly provide the portion of the current conduction path 110 through the switch shown in Figure 1. The flexible conductor may be designed with a sufficient length and sufficient degree of compliancy that, for any foreseeable position of the moveable contact 132, the flexible conductor maybe slack (and not taut or stretched). In this manner, the moveable contact maybe permitted to move freely without significant resistance from the flexible conductor attached to it, and without strain being induced in the flexible conductor. The reliability and longevity of the switch may therefore be improved.

The flexible conductor may be a flexible braid, optionally made from copper. The flexible braid may comprise multiple strands of conductive wire which are woven, twisted, or otherwise attached together to form a flexible conductive medium. By vaiying the diameter of the strands of conductive wire, the compliancy (and flexibility) of the flexible braid can be varied. For example, a highly compliance flexible braid can be made from copper wires with very small diameters. Using copper may provide a flexible conductive medium with low resistance, such that a current can flow along the flexible conductor with minimal heating.

In order to connect the flexible conductor to the first portion of the current line 110A, the flexible conductor may extend through the housing 120. The flexible conductor may pass through the housing in any suitable manner which maintains the housing’s hermetic seal. In some examples, the flexible conductor may pass through an opening in the housing, and the hermetic seal may be maintained around this opening by brazing. This opening may be formed in the top portion 122 or the bottom portion of the housing 124, or at the seal between the top and bottom portions of the housing. In other examples, the flexible conductor may pass through an airtight terminal or seal in the top portion or the bottom portion of the housing. In other examples, only the portion of the current line 110 within the housing 120 maybe flexible. The contact system 130 has a fixed contact 134 disposed within the housing 120 (i.e., an electrically conductive contact which is configured to be held substantially fixed by, for example, the housing). The fixed contact 134 is here disposed in the bottom portion of the housing 124. The fixed contact 134 is electrically connected to a second portion of the current line 110B. The second portion of the current line 110B maybe disposed exterior to the switch housing 120, and the fixed contact may be electrically coupled to the second portion of the current line by any suitable means. For example, the fixed contact may be electrically connected to an airtight terminal, contact, or seal, which can in turn be electrically connected to the second portion of the current line. The fixed contact maybe formed from metal. For example, the fixed contact maybe formed from copper. Using copper may provide a fixed contact with low resistance, such that a current can flow through the fixed conductor with minimal heating. By creating an electrical connection between the moveable contact 132 and the fixed contact 134, a current conduction path can be defined along the current line 110. This electrical connection can be created, for example, by placing the moveable contact in electrical contact with the fixed contact (as shown in Figure 1A). A chamber may surround the contact system 130. The chamber may enclose or partially enclose the moveable contact 132 and the fixed contact 134. In some examples, the chamber may be the interior of the bottom portion of the housing 124. In other examples, the chamber maybe a separate physical structure within the housing 120. The chamber may contain any suitable medium for providing the required arc extinguishing or quenching properties of the switch too. These properties may be dependent on the switching time or the current and/or voltage rating of the switch. In some examples, the medium contained within the chamber may be a vacuum. In other examples, the medium contained within the chamber maybe an inert gas. By using a vacuum or a chemically inert gas (i.e. a gas which does not readily react and form chemical compounds which could damage or degrade the switch), the chamber may be filled with a medium of high dielectric strength which may rapidly extinguish any electrical arcs or discharged between the moveable contact 132 and the fixed contact 134 when the switch is in use. The electromechanical bypass switch too has an electromagnetic actuator 140. The electromagnetic actuator 140 is arranged within the hermetically sealed housing 120, i.e., the hermetically sealed housing may enclose or partially enclose the electromagnetic actuator. The electromagnetic actuator 140 may transform electrical energy into mechanical energy by electromagnetic means, and it will be understood that the electromagnetic actuator may comprise any combination of components and/ or structures suitable for this purpose.

The electromagnetic actuator 140 is configured to open and close the current conduction path 110 which is defined along the current line and through the electromechanical bypass switch too. In the closed state (as shown in Figure 1A), the moveable contact 132 is in electrical contact with the fixed contact 134, and the current conduction path includes the first portion of the current line 110A, the movable contact 132, the fixed contact 134, and the second portion of the current line 110B. A closed current conduction path is provided from the first portion of the current line 110A to the second portion of the current line 110B, and an electrical current carried by the current line is permitted to flow through the switch too. In the open state (as shown in

Figure 1B), the moveable contact 132 is electrically separated from the fixed contact 134. An open current conduction path is provided, and no electrical current is permitted to flow through the switch too. The electromagnetic actuator 140 opens and closes the current conduction path 110 by actuating (or moving) the moveable contact 132 of the contact system 130. In some examples, the moveable contact 132 may comprise one or more magnetic portions which the electromagnetic actuator 140 is configured to electromagnetically interact with in order to cause the actuation of the moveable contact. In other examples, the moveable contact 132 may be coupled to or otherwise actuated by another component which the electromagnetic actuator 140 is configured to actuate or move.

The moveable contact 132 is actuated along a first axis 150. The housing 120 of the switch may be configured such that motion of the moveable contact is substantially confined to motion along the first axis. As such, force components acting on the moveable contact 132 in a direction different from (for example, perpendicular to) the first axis 150 may only cause negligible lateral motion of the moveable contact. The first axis may be aligned to pass through the bottom portion of the housing 124 and the top portion of the housing 122. The first axis may pass through the fixed contact 134 of the contact system such that the fixed contact 134 and the moveable contact 132 are substantially aligned when they are electrically connected together. This may provide a larger contact area, and hence a more reliable electrical connection.

The electromagnetic bypass switch too of this example has a resilient member 160. The resilient member is made from a resiliently (e.g., elastically) deformable material or is resiliently deformable by form. The resilient member may be a spring, or could be a flexible component made from e.g., plastic or rubber. The resilient member 160 is configured to urge (i.e., by imparting a force on) the moveable contact 132 along the first axis 150 and into the first position shown in Figure 1A. This first position may be a furthermost position of the moveable contact in one direction along the first axis 150 during normal operation of the switch.

In some examples, one end of the resilient member 160 may be attached to or placed against (e.g., abutting) the housing 120 or the electromagnetic actuator 140 and the other end of the resilient member may be attached to or contacting the moveable contact 132. The moveable contact may comprise a number of portions, for example, a contact portion and a body portion. The resilient member maybe directly attached/connected to the contact portion (i.e., the portion of the moveable contact which is configured to electrically connect to the fixed contact) or it may be indirectly connected to the contact portion, via the body portion for example. Additionally or alternatively, the resilient member may be coupled to the moveable contact via one or more components of the electromagnetic actuator. In some examples, the resilient member 160 may be arranged to impart a force on the moveable contact 132 at any position of the moveable contact along the first axis 150 during normal operation of the switch. In order to actuate the switch, the force applied by the electromagnetic actuator can be greater than the urging/biasing force of the resilient member. With the moveable contact in the first position, the resilient member 160 may be slightly deformed. In this manner, the moveable contact 132 may be securely held in the first position with the switch too in an initial state (before actuation of the switch). This may reduce the risk of accidental opening of the switch due to vibrations or impacts. In other examples, the resilient member 160 may be arranged to be non-deformed when the moveable contact is in the first position.

The electromagnetic actuator 140 has a voice coil 142. As used herein, the term “voice coil” refers to any type of electrically conductive coil which is suitable for use in an electromagnetic actuator 140. The voice coil 142 is disposed in the top portion of the housing 122. The top portion of the housing may enclose or partially enclose the voice coil. In some examples, the voice coil 142 may be fixedly retained in place by the top portion of the housing 122, or it maybe fixedly retained in place by one or more other components of the electromagnetic actuator 140. In other examples, the voice coil may be free to oscillate during operation of the electromagnetic actuator. In these examples, the voice coil may be fixedly retained by the housing or the electromagnetic actuator at only one end of the coil, for example. It will be understood that other electromagnetic actuator topologies which incorporate a voice coil are possible. A current can be applied to the voice coil 142. This is a separate current from any current referred to herein which may flow through the current conduction path or the current line when the moveable contact and fixed contact are electrically connected to one another. The current applied to the voice coil can be provided by any suitable means. The size of the current required by the switch too will depend on the specifications of the electromagnetic actuator 140 and the desired properties of the switch. The current may be a transient current which passes through the voice coil in a short period of time (e.g., 1 second, too milliseconds, 10 milliseconds, or 1 millisecond), or the current maybe applied over a prolonged period of time (e.g. 1 minute or 1 hour). In some examples, the current applied to the voice coil 142 may be provided by one or more capacitors. The one or more capacitors can be configured to discharge through the voice coil to provide the current. Using capacitors can allow a high current to be provided over a very short period of time, increasing the force exerted on the moveable contact, and the speed at which the switch can operate. Thus, rapid switching can be facilitated.

As discussed above, in the initial state, the moveable contact 132 is held in the first position due to the force applied by the resilient member 160 (as shown in Figure 1A). Although Figure 1A shows the moveable contact 132 electrically connected to the fixed contact 134 with the current conduction path closed in the first position (and with the switch too in the initial state), it will be appreciated that alternatively, the moveable contact 132 could be electrically separated from the fixed contact 134 with the current conduction path open in the first position. In this alternative scenario, it will be understood that at least the moveable contact 132, fixed contact 134, resilient member 160, and electromagnetic actuator 140 maybe otherwise positioned, as necessary. When a current is applied to the voice coil 142, the electromagnetic actuator 140 is configured to cause the moveable contact 132 to move along the first axis 150 from the first position to a second position (which is shown in Figure 1B). Although Figure 1B shows the moveable contact 132 electrically separated from the fixed contact 134 with the current conduction path open in the second position, it will be appreciated that alternatively, the moveable contact 132 could be electrically connected to the fixed contact 134 with the current conduction path closed in the second position. In this alternative scenario, it will be understood that at least the moveable contact 132, fixed contact 134, resilient member 160, and electromagnetic actuator 140 maybe otherwise positioned, as necessary.

By using the arrangement shown in Figure 1, with the moveable contact 132 electrically connected to the fixed contact 134 with the current conduction path closed in the first position and the moveable contact 132 electrically separated from the fixed contact 134 with the current conduction path open in the second position, the switch can be configured to rapidly open the current line 110. Such a switch maybe used in safety applications, for example in applications where a power supply needs to rapidly be switched away from faulty or damaged equipment connected to it. The electromagnetic actuator 140 may cause the moveable contact 132 to move along the first axis 150 from the first position to the second position by any suitable electromagnetic means. It will be understood that the electromagnetic actuator 140 may comprise any combination of components and/or structures that, in combination with the voice coil 142, are suitable for this purpose. It will also be understood that the moveable contact 132 may comprise any combination of components and/or portions that allow it to be electromagnetically actuated or moved by electromagnetic actuation. For example, it may comprise one or more magnetic portions.

With the moveable contact 132 in the second position, the resilient member 160 may be further compressed (compared to the compression of the resilient member with the moveable contact in the first position), i.e., the urging/biasing force provided by the resilient member 160 on the moveable contact 132 may be greater in the second position than in the first position. With the moveable contact 132 in the second position, the current applied to the voice coil may then be removed to close (or open, depending on the device configuration) the switch. In response to the removal of the voice coil current, the resilient member 160 is arranged to act as a biasing member. The resilient member is configured to bias the moveable contact 132 along the first axis 150; in this way, the resilient member is configured to urge the moveable contact to move from the second position towards the first position. In other words, upon removal of the current applied to the voice coil, the elastically deformed (compressed) resilient member returns to its initial (only slightly deformed or non-deformed) state, and this decompressing and subsequent expansion of the resilient member 160 provides a biasing force which causes the moveable contact to move along the first axis 150 from the second position to the first position. In some examples (such as examples where the top portion of the housing 122 is formed from a magnetic material), the electromagnetic actuator 140 may take the following form (not shown in Figure 1). The electromagnetic actuator 140 may comprise a number of further components which are disposed in the top portion of the housing 122, i.e., the following components maybe enclosed or partially enclosed within the top portion of the housing. These components may include a magnetic core.

This magnetic core may be formed from any magnetic material, for instance iron or steel. This magnetic core may have a suitable magnetic permeability for guiding a magnetic field. These components may also comprise one or more permanent magnets at least partially enclosing (e.g., at least partially surrounding) the magnetic core. These one or more permanent magnets may provide a permanent magnetic field to be guided by the magnetic core. These components may also comprise a bobbin at least partially enclosing the magnetic core. The voice coil maybe wound on the bobbin. In some examples, the one or more permanent magnets and the bobbin may substantially entirely enclose (surround) the magnetic core.

For example, an electromagnetic actuator 140 may comprise a magnetic core, one or more permanent magnets, a bobbin, and the voice coil 142 wound on the bobbin. In this example, the one or more permanent magnets generate a permanent magnetic field which is guided by at least the magnetic core (and may also be guided by the top portion of the housing 122 in examples where the top portion of the housing is formed from a magnetic material). When the current is applied to the voice coil 142, the magnetic field is guided (i.e., a magnetic field is formed) that drives the moveable contact 132, along the first axis, from the first position to the second position. For example, the moveable contact may include one or more magnetic portions which the magnetic field interacts with to drive the moveable contact. Additionally or alternatively, the magnetic field may interact with one or more other components which may be coupled to or otherwise be configured to drive the moveable contact when the current is applied to the voice coil. These examples may provide an electromagnetic actuator which is capable of providing a strong magnetic force, and therefore which is capable of providing fast switching of the moveable contact.

In the example described above (or other examples with different electromagnetic actuator configurations), the moveable contact 132 maybe arranged in the bottom portion of the housing 124 and may be integrated with the bobbin. In other words, the moveable contact may be (at least partially) disposed, with the fixed contact, in the bottom portion of the housing. The moveable contact may then be integrated with (e.g., configured to pass through) the bobbin. For example, the bobbin may be disposed in the top portion of the housing 122 adjacent to the hermetic seal between the top and bottom portions of the housing. The moveable contact 132 may comprise a contact portion and a body portion, with the contact portion (configured to make electrical contact with the fixed contact) disposed in the bottom portion of the housing 124, and the body portion extending from the contact portion, through the bobbin, into the top portion of the housing 122. In this instance, a hole or seal may extend through the bobbin and the top and bottom portions of the housing, and the contact portion of the moveable contact 132 maybe arranged to extend through this hole or seal. Integrating the moveable contact with the bobbin in this manner may allow the moveable contact to at least partially extend into the top portion of the housing (as well as the bottom portion of the housing). This arrangement may facilitate a more space-efficient layout of components within the housing. For example, with this arrangement, it maybe possible to place the resilient member 160 in the top portion of the housing, which may reduce the overall size required for the switch.

As described above, when the current being applied to the voice coil 142 is removed, the resilient member 160 urges the moveable contact 132 back along the first axis 150 from the second position back to the first, initial position. In some applications, it may be desirable for the switch to “latch” when in the second position, such that the current applied to the voice coil can be removed without the moveable contact returning to the first position. For example, in switches where the current conduction path 110 is open in the second position (as shown in Figure 1B), it may be desirable for the switch to latch in the second position such that faulty or damaged equipment connected to the switch remains electrically isolated after the switch too is actuated. This arrangement allows the current applied to the voice coil to be removed shortly after the moveable contact has moved from the first position to the second position (i.e. the current applied to the voice coil can thus be very short in duration), with the mechanical latch retaining an upper portion (see further explanation below) of the electromagnetic actuator 140 in place by mechanical means rather than electromagnetic means. In this manner, the time over which the current needs to be applied to the voice coil can be reduced, and the power requirements of the switch can therefore also be reduced.

In some examples, the top portion of the housing 122 may further have a bellows seal (not shown in Figure 1). As referred to herein, a “bellows seal” maybe any mechanical seal through which components of the switch too may extend whilst maintaining the hermetic seal of the housing 120. The bellows seal maybe disposed on the upper surface of the top portion of the housing 122. The electromagnetic actuator 140 may comprise an upper portion extending through the bellows seal (i.e., at least part of the upper portion of the electromagnetic actuator is disposed exterior to the housing). In some examples, this upper portion may be connected, directly or indirectly, to the moveable contact 132. In examples where the moveable contact comprises a body portion, the upper portion of the electromagnetic actuator may be coupled to the body portion of the moveable contact. In other examples, the upper portion of the electromagnetic actuator and the moveable contact (or the body portion of the moveable contact) may be integrally formed. Using a bellows seal may allow the housing 120 to remain hermetically sealed, whilst also facilitating further components of the switch too to be located outside the housing, preventing inefficient use of the densely populated housing. Using a bellows seal may also allow these potential further components of the switch too located outside the housing to easily be manually accessed, if necessary.

The switch may have a mechanical latch (not shown in Figure 1) disposed exterior or interior to the housing 120. As referred to herein, a “mechanical latch” maybe any suitable mechanism which is configured to fixedly retain (hold in place) the upper portion of the electromagnetic actuator when the moveable contact 132 is in the second position. In these examples, the upper portion of the electromagnetic actuator is directly or indirectly coupled to the moveable contact 132, such that retaining the upper portion of the electromagnetic actuator causes the moveable contact to be securely retained in the second position. The mechanical latch may be spring -loaded, for example. In this manner, the mechanical latch may be configured to automatically latch when the moveable contact is in the second position. Specific examples of mechanical latches are described below with reference to Figures 2 and 3.

With reference to Figure 2 (Figures 2A and 2B), a specific example of an electromechanical bypass switch too is described in more detail.

The electromechanical bypass switch 200 may be the switch too described above with reference to Figure 1. The switch 200 comprises a housing 220 (which maybe the same as housing 120 described above with reference to Figure 1), a contact system 230 (which may be the same as contact system 130 described above with reference to Figure 1), an electromagnetic actuator 240 (not specifically labelled in Figure 2, but which may be the same as electromagnetic actuator 140 described above with reference to Figure 1), and a resilient member 260 (which may be the same as resilient member 160 described above with reference to Figure 1). The switch 200 may also comprise some or all of the other components described above in relation to switch too shown in Figure 1.

Although switch 200 shows a specific combination of some of the features described above in relation to Figure 1, it will be appreciated that the features described above in relation to Figure 1 can be combined in any other suitable manner. An electromechanical bypass switch 200 for use in a hybrid circuit breaker is described. The switch 200 is configured for connection to a current line of the hybrid circuit breaker. A current conduction path 210 (not shown in Figure 2) is defined along the current line and through the electromechanical bypass switch 200. Figure 2 shows where a first portion of the current line, 210A, is configured to be connected and where a second portion of the current line, 210B, is configured to be connected.

Electromechanical bypass switch 200 has a housing 220 with a top portion 222 and a bottom portion 224. In this example, the top portion of the housing 222 is formed from magnetic steel and the bottom portion of the housing 224 is formed from a ceramic material. The top portion and the bottom portion of the housing are hermetically sealed together. In this example, the top portion and the bottom portion of the housing are brazed together to form the hermetic seal. The exterior sides of the top and bottom portions of the housing are also airtight to provide a hermetically sealed housing 220. Electromechanical bypass switch 200 has a contact system 230 arranged within the hermetically sealed housing 220. The contact system 230 has a moveable contact 232 electrically connected to the first portion of the current line 210A. In this example, the moveable contact is connected to the first portion of the current line via a flexible conductor 215. The flexible conductor 215 may be a flexible copper braid, for example. In this example, the flexible conductor extends through a hole in the bottom portion of the housing 224, and the hermetic seal around this hole is maintained by brazing. The contact system 230 also has a fixed contact 234 disposed in the bottom portion of the housing 224 and electrically connected to the second portion of the current line 210B. The fixed contact 234 may be connected to the second portion of the current line via a terminal or a connector. The bottom portion of the housing 224 comprises a chamber surrounding the contact system 230 (surrounding the moveable contact 232 and the fixed contact 234). In this example, the chamber is defined by the inner walls of bottom portion of the housing 224. The chamber may contain a vacuum or an inert gas, for example. The moveable contact 232 and the fixed contact 234 may be wholly or partially formed from metal, for example copper.

Electromechanical bypass switch 200 has an electromagnetic actuator 240 (not specifically labelled in Figure 2) arranged within the hermetically sealed housing 220 and configured to open and close the current conduction path defined along the current line and through the switch 200 by actuating the moveable conductor 232 of the contact system 230 along a first axis 250 of the electromagnetic actuator. In this example, the electromagnetic actuator is substantially arranged within the top portion of the hermetically sealed housing. The electromagnetic actuator 240 comprises a voice coil 242 disposed in the top portion of the housing 222. In this example, the electromagnetic actuator 240 further comprises a magnetic core 243. The magnetic core maybe made from steel or iron, for example. The electromagnetic actuator can also comprise one or more permanent magnets 244 at least partially enclosing the magnetic core. In this example, the electromagnetic actuator further comprises three permanent magnets 244A, 244B, 244C, which are arranged such that the permanent magnets partially enclose the magnetic core 243. The permanent magnets may be rectangular bar magnets, and the rectangular bar magnets maybe arranged such that their south pole is positioned adjacent to the magnetic core 243, and their north pole is positioned adjacent to the top portion of the housing 222, for example (as illustrated in Figure 2A). In this example, the electromagnetic actuator further comprises a bobbin 245, which is arranged such that it partially encloses the magnetic core 243. The voice coil 242 is wound on (and fixedly retained by) the bobbin. In this example, the moveable contact 232 is arranged in the bottom portion of the housing 224 and is integrated with the bobbin 245. Specifically, in this example, the moveable contact 232 comprises a contact portion arranged in the bottom portion of the housing and a body portion which is coupled to the contact portion. The contact portion of the moveable contact 232 is configured to make electrical contact with the fixed contact 234. The body portion of the moveable contact extends upwards from the contact portion and is electrically connected to the flexible connector 215. The body portion of the moveable contact extends upwards through the hermetic seal between the top and bottom portions of the housing 222, 224 and through (i.e., such that it is integrated with) the bobbin 245.

Electromechanical bypass switch 200 has a resilient member (in this example, a compression spring) 260 configured to urge the moveable contact 232 along the first axis 250 and into a first position. In this example, the moveable contact 232 is electrically connected to the fixed contact 234 in the first position (as shown in Figure 2A) and is electrically separate from the fixed contact 234 in the second position (as shown in Figure 2B). In this example, the resilient member 260 is disposed in the top portion of the housing 222. Specifically, in this example, the resilient member 260 is mounted such that a lower end abuts (and is optionally connected to) the body portion of the moveable contact 232, and the upper end abuts (and is optionally connected to) the magnetic core 243 of the electromagnetic actuator.

In this example, the top portion of the housing 222 further comprises a bellows seal 226, and the electromagnetic actuator 240 comprises an upper portion 246 extending through the bellows seal 226. The upper portion 246 of the electromagnetic actuator may be connected to the moveable contact 232 (specifically, the body portion of the moveable contact), or may be integrally formed with the moveable contact 232 (specifically, the body portion of the moveable contact), for example. The upper portion 246 of the electromagnetic actuator may be formed from an electrically insulating material. In this example, the bellows seal extends through the top portion of the housing 222 and permanent magnet 244B.

In this example, the electromechanical bypass switch 200 further comprises a mechanical latch 270 disposed exterior to the housing 220 and configured to fixedly retain the upper portion 246 of the electromagnetic actuator 240 when the moveable contact 232 is in the second position. Specifically, in this example, the mechanical latch 270 comprises a spring-operated arm portion which is configured to interact with a notch 247 in the upper portion 246 of the electromagnetic actuator to fixedly retain the upper portion. The spring-operated arm portion is shaped such that it may interlock or engage / mate with the notch 247 and hold the upper portion 246 of the electromagnetic actuator securely in place. The notch 247 is located in the upper portion 246 of the electromagnetic actuator such that the spring-operated arm portion only interlocks with the notch when the moveable contact 232 (which the upper portion of the electromagnetic actuator is connected or coupled to, as explained above) is in the second position. It will be understood that an alternative mechanical latch (for example, the second example mechanical latch described below in relation to Figure 3B) can be used. In another example (not shown), the latch may instead be disposed interior to the housing. Electromechanical bypass switch 200 may operate in the same way or a similar way to that the operation of switch too described above in relation to Figure 1. In the initial state, the moveable contact 232 is held securely in the first position due to the force applied by spring 260 (as shown in Figure 2A). A current can be applied to the voice coil 242. The current may be provided by any suitable means, for example by one or more discharging capacitors. A magnetic field is formed by the permanent magnets 244A, 244B, 244C, and is guided by at least the magnetic core and the top portion of the housing. When the current is applied to the voice coil 242, the magnetic field is guided (i.e. a magnetic field is formed) to interact with, for example, one or more magnetic portions in the moveable contact 232, such that the moveable contact is driven from the first position, along the first axis 250, to the second position (as shown in Figure 2B). The one or more magnetic portions of the moveable contact may be provided in the body portion and/or the contact portion of the moveable contact, for example. Alternatively, the body portion and/ or the contact portion may be formed from magnetic material to provide the one or more magnetic portions. When the moveable contact 232 is in the second position, the mechanical latch 270 retains the upper portion 246 of the electromagnetic actuator, holding the moveable contact 232 in the second position indefinitely (until the mechanical latch is released or otherwise reset). With reference to Figure 3A, a first example mechanical latch 370 is described in more detail. The first example mechanical latch 370 may be the mechanical latch 270 described above with reference to Figure 2 or the mechanical latch described above with reference to Figure 1.

Figure 3A shows the upper portion 346 (which may be the same as upper portion 246 described above in relation to Figure 2) of the electromagnetic actuator extending through the bellows seal 326 (which maybe the same as bellows seal 226 described above in relation to Figure 2) in the top portion of the housing 322 (which maybe the same as upper portion of the housing 222 described above in relation to Figure 2). Mechanical latch 370 comprises arm portion 372. The arm portion 372 has a protruding section which is shaped to interlock or mate with a notch 347 provided in the upper portion 346 of the electromagnetic actuator. Although Figure 3A shows a protruding portion with a tapered triangular shape, it will be understood that any suitable shape (and corresponding notch shape) can be used. When the arm portion 372 and the notch 347 are interlocked, the upper portion 346 of the electromagnetic actuator is rigidly held in place. Mechanical latch 370 also comprises spring-operated hinge 374. The spring-operated hinge is configured to drive the arm portion 372 in a clockwise direction about the hinge 374. As the upper portion 346 of the electromagnetic actuator moves vertically upwards (from the position shown in Figure 3A) with the movement of the moveable contact along the first axis from the first position to the second position, the spring-operated hinge 374 causes the arm portion 372 to automatically interlock with the notch 347. The mechanical latch 370 can be reset in any suitable manner, for example by causing (manually or otherwise) anticlockwise rotation of the arm portion 372 about the spring-operated hinge 374 to remove the arm portion 372 from the notch 347.

With reference to Figures 3B, 3C, a second example mechanical latch 370 is described in more detail. The second example mechanical latch maybe the mechanical latch described above with reference to Figure 1.

Figure 3B shows the upper portion 346 (which may be the same as upper portion 246 described above in relation to Figure 2) of the electromagnetic actuator extending through the bellows seal 326 (which maybe the same as bellows seal 226 described above in relation to Figure 2) in the top portion of the housing 322 (which maybe the same as upper portion of the housing 222 described above in relation to Figure 2). In this position, the moveable contact is in electrical contact with the fixed contact and the conduction path is closed.

The latch comprises two resiliently deformable members 376A, 376B, which may be resilient in form and/ or material. In this example, members 376A, 376 B are compression springs. The springs are fixed at points 378A, 378B, with the other ends of the springs being pivotably coupled to the upper portion 346. In other words, a first end of each resiliently deformable member is pivotable coupled to the upper potion 346 and a second end 378A, 378B opposite the first end is fixed. The fixed end may be fixed to the housing (when the latch is disposed inside the housing) or to another fixed component disposed outside of the housing. The springs exert a force on the upper portion in direction 380 (illustrated by the arrow in Figure 3B). This force acts to press the moveable contact into contact with the fixed contact, which can help improve the electrical connection.

As the electromagnetic actuator 140 moves the moveable contact away from the fixed contact to open the current conduction path, the upper portion 346 moves vertically upwards in a direction opposite direction 380. The downward force applied by the springs is less than the upwards force exerted by the electromagnetic actuator, allowing the upper portion to move and the contact system 130 to open. As the upper portion 346 moves upward, it compresses the springs 376A, 376B until the ends of the springs 376A, 376B pivot (or toggle) and change orientation to the position shown in Figure 3C. In this arrangement, the springs exert a force on the upper portion in a direction 390 opposite direction 380 (illustrated by the arrow in Figure 3C). This force acts to keep the moveable contact away from the fixed contact, preventing the contact system from closing again. In particular, the force applied by springs 376A and 376B in direction 390 is greater than the force applied by the resilient member 160 (inside the housing) and therefore the contact system 130 stays in the open position even though the current is removed from the voice coil (i.e., the capacitor bank supply is discharged).

The mechanical latch 370 can be reset in any suitable manner, for example by causing (manually or otherwise) rotation of the resiliently deformable members (or springs) 376A, 376 B around their pivot points so that the force exerted by the springs flips back to a force in direction 380. As soon as the members 376A, 376B pivot (or toggle) then the contact system 130 will close in response to the force applied by the members 376A, 376B and the resilient member 160 inside the housing. With reference to Figure 4, a hybrid circuit breaker 400 is described in more detail.

The hybrid circuit breaker 400 has an input connector 410 configured to be connected to a power grid. The power grid may be any suitable power source, for example, a direct current voltage source or an alternating current voltage source.

The hybrid circuit breaker 400 has an output connector 420 configured to be connected to a load. The load may be any suitable electrical load, and may provide a load resistance. In some examples, the load may comprise high voltage and/ or high current electrical machinery or equipment. Such machinery or equipment can develop short circuits or other faults, which can lead to these high voltages/currents damaging the equipment and/or potentially exposing users of the equipment to danger (e.g., electrocution). In scenarios where faults in the load develop, it is desirable to provide a hybrid circuit breaker 400 which can quickly remove the power source (i.e. , the power grid) from the load.

The hybrid circuit breaker 400 has a current path 430 connecting the input connector and the output connector. The current path 430 may any suitable current path which allows the power grid to provide power to the load. The current path may include a common ground for the input connector 410 and the output connector 420 (and therefore for the power grid and the load).

The hybrid circuit breaker 400 has an electromechanical bypass switch 440 according to the first aspect. The electromechanical bypass switch 440 may be the switch too described above with reference to Figure 1 or the switch 200 described above with reference to Figure 2. The electromechanical bypass switch 440 is arranged in the current path 430. The switch 440 may be arranged in any manner such that actuation of the switch can open and close the current path 430 connecting the input connector 410 to the output connector 420 (and therefore opening and closing the path between the power grid and the load). The current path 430 described here in relation to Figure 4 maybe the “current line” described above with reference to Figures 1 and 2.

The hybrid circuit breaker 400 has a semiconductor circuit 450 in parallel with the electromechanical bypass switch 440. The semiconductor circuit 450 may comprise any suitable combination of components which are suitable for acting as a solid-state switch. In normal operation (i.e., in the state of Figures 1A, 2A), the semiconductor circuit 450 is off, and all current flows through the electromechanical bypass switch 440. The hybrid circuit breaker 400 has a control unit 460 being capable of controlling a commutation from the current path 430 in which the electro-mechanical bypass switch 440 is arranged, to the semiconductor circuit 450 in case of a switch-off operation. Although control unit 460 is shown in Figure 4 as not directly connected to the other components of the hybrid circuit breaker 400, the control unit 460 maybe electrically connected to any or all of the components of hybrid circuit breaker 400 in order to control the operation of the device.

A switch-off operation (i.e., disconnecting the power grid from the load, or disconnecting the input connector 410 from the output connector 420) may be required when, as discussed above, a fault develops in the load. In this scenario, the control unit 460 can be configured to automatically initiate the switch-off operation (e.g., based on an unexpectedly high ‘fault’ current being detected by the control unit). Alternatively, a switch-off operation may be initiated manually, for example when a user wishes to perform maintenance or repairs on the load equipment. In this scenario, the user may be able to user the control unit to initiate the switch-off operation.

To perform a switch-off operation, the control unit 460 controls a commutation (i.e., transfer of current) from the current path 430 to the semiconductor circuit 450.

Firstly, the semiconductor circuit 450 is turned on. Then, the control unit 460 controls actuating of the electromechanical bypass switch 440. As described above in relation to

Figures 1 and 2, the electromechanical bypass switch can be actuated by applying a current to the voice coil. The control unit 460 may cause this current to be provided to the voice coil, or the current may be directly provided by the control unit 460. As the moveable contact of the switch 440 is driven from the first position to the second position, the resistance increases on current part 430 and the current along the current path 430 is diverted to the semiconductor circuit 450. Once the electromechanical switch 440 is opened (or almost opened), the semiconductor circuit 450 is then turned off to open the switch 400 with reduced or no arc formation at the electromechanical bypass switch 440. In some examples, the hybrid circuit breaker 400 may further comprise one or more capacitor banks to provide the current applied to the voice coil. Using one or more banks of capacitors may allow a high current to be applied to the voice coil in a short period of time, permitting a faster switch-off operation. The one or more capacitor banks may be part of the control unit 460. This arrangement may reduce the number of components required for the hybrid circuit breaker as well as reducing its overall size. In some examples, the one or more capacitor banks may comprise a first capacitor bank and a second capacitor bank. The two capacitor banks can have different capacities, e.g., the first capacitor bank may have a higher capacity than the second capacitor bank. This may allow at least two different switching speeds to be provided by the hybrid circuit breaker which could, for example, be selected depending on the power and safety requirements of the particular situation in which the hybrid circuit breaker is used. With reference to Figure 5, a method of operating an electromechanical bypass switch (for example, the electromechanical bypass switch described above with reference to Figures 1, 2, 3 and/or 4) is described in more detail.

At step 510, the method comprises applying the current to the voice coil. The current applied to the voice coil can be provided by any suitable means. In some examples, the current applied to the voice coil may be provided by one or more capacitors. The one or more capacitors can be configured to discharge through the voice coil to provide the current. In response to the application of the current to the voice coil, at step 520, the method comprises moving, by the electromagnetic actuator, the moveable contact along the first axis from the first position to the second position. The electromagnetic actuator may cause the moveable contact to move along the first axis from the first position to the second position by any suitable electromagnetic means. It will be understood that the electromagnetic actuator may comprise any combination of components and/or structures that, in combination with the voice coil, are suitable for this purpose. It will also be understood that the moveable contact may comprise any combination of components and/or portions that allow it to be electromagnetically actuated or moved by electromagnetic actuation. In examples where the switch comprises the mechanical latch and the electromagnetic actuator comprises the upper portion extending through the bellows seal, the method may further comprise step 530 (denoted as optional by the dotted lines in Figure 5). At step 530, the method comprises fixedly retaining, by the mechanical latch, the upper portion of the electromagnetic actuator when the moveable contact is in the second position. The mechanical latch may be any suitable mechanism which is configured to fixedly retain (hold in place) the upper portion of the electromagnetic actuator when the moveable contact is in the second position. In these examples, the upper portion of the electromagnetic actuator is directly or indirectly coupled to the moveable contact, such that retaining the upper portion of the electromagnetic actuator causes the moveable contact to be securely retained in the second position. The mechanical latch may be spring-loaded, for example. In this manner, the mechanical latch may be configured to automatically latch as soon as the moveable contact moves into the second position.

In some examples, the method may further comprise steps 540, 550, and 560 (denoted as optional by the dotted lines in Figure 5). Subsequent to fixedly retaining the upper portion of the electromagnetic actuator, at step 540, the method comprises removing the current from the voice coil. In examples where the current is provided by one or more capacitors, the current may be removed from the voice coil when the one or more capacitors have discharged, for example. With no current flowing through the voice coil, the moveable contact remains in the second position (due to the mechanical latch).

At step 550, the method comprises manually releasing the mechanical latch. A user may directly release the latch by hand, or may be able to release the latch by operating a reset button or other electrically assisted reset means which releases the mechanical latch.

In response to the manual release of the mechanical latch, at step 560, the method comprises urging, by the resilient member, the moveable contact along the first axis from the second position to the first position. With no current in the voice coil and with the mechanical latch released, the only substantial force acting on the moveable contact is that supplied by the resilient member, which is compressed with the moveable conductor in the second position. The resilient member is arranged to act as a biasing member. The resilient member is configured to bias the moveable contact along the first axis; in this way, the resilient member is configured to urge the moveable contact to move from the second position towards the first position. In other words, the elastically deformed (compressed) resilient member returns to its initial (only slightly deformed or non-deformed) state, and this decompressing and subsequent expansion of the resilient member provides a biasing force which causes the moveable contact to move along the first axis from the second position to the first position. It is noted herein that while the above describes various examples of the electromechanical bypass switch of the first aspect, the hybrid circuit breaker of the second aspect, and the method of the third aspect, these descriptions should not be viewed in a limiting sense. Rather, there are several variations and modifications which maybe made without departing from the scope of the present invention as defined in the appended claims.

Claims

1. An electromechanical bypass switch (too, 200) for use in a hybrid circuit breaker, the electromechanical bypass switch (too, 200) configured for connection to a current line of the hybrid circuit breaker and comprising: a housing (120, 220) with a top portion (122, 222) and a bottom portion (124, 224), wherein the top portion (122, 222) of the housing (120, 220) is formed from a magnetic material and wherein the top portion (122, 222) and the bottom portion (124, 224) of the housing (120, 220) are hermetically sealed together; a contact system (130, 230) arranged within the hermetically sealed housing

(120, 220) and comprising: a moveable contact (132, 232) electrically connected to a first portion of the current line, and a fixed contact (134, 234) disposed in the bottom portion (124, 224) of the housing (120, 220) and electrically connected to a second portion of the current line; and an electromagnetic actuator (140, 240) arranged within the hermetically sealed housing (120, 220) and configured to open and close a current conduction path (110, 210) defined along the current line and through the electromechanical bypass switch (too, 200) by actuating the moveable contact (132, 232) of the contact system (130, 230) along a first axis of the electromagnetic actuator (140, 240), the electromagnetic actuator (140, 240) comprising a voice coil (142) disposed in the top portion (122, 222) of the housing (120, 220), wherein, when a current is applied to the voice coil (142), the electromagnetic actuator (140, 240) is configured to cause the moveable contact (132, 232) to move along the first axis from a first position to a second position; wherein the moveable contact (132, 232) is electrically connected to the fixed contact (134, 234) in one of the first and second positions to close the current conduction path (110, 210) along the current line, and is electrically separate from the fixed contact (134, 234) in the other of the first and second positions to open the current conduction path (110, 210) along the current line.

2. The switch of claim 1, wherein the moveable contact (132, 232) is electrically connected to the fixed contact (134, 234) in the first position and is electrically separate from the fixed contact (134, 234) in second position.

3. The switch of claim 1 or claim 2, wherein the magnetic material is a magnetic steel.

4. The switch of claim 3, wherein the electromagnetic actuator (140, 240) further comprises the following components disposed in the top portion (122, 222) of the housing (120, 220): a magnetic core (243); one or more permanent magnets (244) at least partially enclosing the magnetic core (243); and a bobbin (245) at least partially enclosing the magnetic core (243), wherein the voice coil (142) is wound on the bobbin; wherein the top portion (122, 222) of the housing (120, 220), the magnetic core (243), the one or more permanent magnets (244), the bobbin, and the voice coil (142) are arranged such that they interact to form a magnetic field that drives the moveable contact (132, 232) from the first position to the second position when the current is applied to the voice coil (142).

5. The switch of claim 4, wherein the moveable contact (132, 232) is arranged in the bottom portion (124, 224) of the housing (120, 220) and is integrated with the bobbin.

6. The switch of any of claims 1-5, wherein the bottom portion (124, 224) of the housing (120, 220) is formed from a ceramic material. 7. The switch of any of claims 1-6, wherein the bottom portion (124, 224) of the housing (120, 220) comprises a chamber surrounding the contact system (130, 230), wherein the chamber contains: a vacuum; or an inert gas

8. The switch of any of claims 1-7, wherein the hermetic seal between the top and bottom portions (122, 222), (124, 224) of the housing (120, 220) is formed by brazing the top and bottom portions (122, 222), (124, 224) of the housing (120, 220) together.

9. The switch of any of claims 1-8, wherein the moveable contact (132, 232) is electrically connected to the first portion of the current line by a flexible conductor (215); optionally wherein the flexible conductor is a flexible copper braid.

10. The switch of claim 9, wherein the flexible conductor extends from the housing (120, 220), and wherein a hermetic seal is formed around the flexible conductor by brazing. 11. The switch of any of claims 1-10, further comprising: a mechanical latch (270, 370) configured to fixedly retain an upper portion (246, 346) of the electromagnetic actuator (140, 240) when the moveable contact (132, 232) is in the second position. 12. The switch of claim 11, wherein mechanical latch (270, 370) is disposed exterior to the housing (120, 220), and wherein the top portion (122, 222) of the housing (120, 220) further comprises a bellows seal (326), the upper portion of the electromagnetic actuator (140, 240) extending through the bellows seal (326). 13. The switch of claim 11 or claim 12, wherein the mechanical latch (270, 370) comprises: a spring-operated arm portion (372) configured to interact with a notch (247, 347) in the upper portion of the electromagnetic actuator (140, 240) to fixedly retain the upper portion; or two resiliency deformable members (376A, 376B), each pivotably coupled at a first end to the upper portion and each fixed at a second end (378a, 378b) opposite the first end.

14. The switch of any of claims 1-13, wherein the current applied to the voice coil (142) is provided by one or more capacitors.

15. The switch of any of claims 1-14, wherein the moveable contact (132, 232) and the fixed contact (134, 234) are formed from metal; optionally wherein the metal is copper.

16. The switch of any of claims 1-15, further comprising a resilient member (160, 260) configured to urge the moveable contact (132, 232) along the first axis and into the first position; optionally, wherein the resilient member is a spring.

17. A hybrid circuit breaker (400) comprising: an input connector (410) configured to be connected to a power grid; an output connector (420) configured to be connected to a load; a current path (430) connecting the input connector and the output connector; an electromechanical bypass switch (100, 200, 440) according to any of claims

1-16 being arranged in the current path (430); a semiconductor circuit (450) in parallel with the electro-mechanical bypass switch (100, 200, 440); and a control unit (460) being capable of controlling a commutation from the current path (430) in which the electromechanical bypass switch (100, 200, 440) is arranged, to the semiconductor circuit (450) in case of a switch-off operation.

18. The hybrid circuit breaker of claim 17, further comprising: one or more capacitor banks to provide the current applied to the voice coil (142).

19. The hybrid circuit breaker of claim 18, wherein the one or more capacitor banks comprise a first capacitor bank and a second capacitor bank, wherein the first capacitor bank has a higher capacity than the second capacitor bank.

20. The hybrid circuit breaker of claims 18 or 19, wherein the one or more capacitor banks are part of the control unit (460).

21. A method of operating an electromechanical bypass switch (too, 200) according to any of claims 1-16, wherein the method comprises: applying (510) the current to the voice coil (142); and in response to the application of the current to the voice coil (142), moving

(520), by the electromagnetic actuator (140, 240), the moveable contact (132, 232) along the first axis from the first position to the second position.

22. The method of claim 21 when operating an electromechanical bypass switch (too, 200) according to claim 11 or claim 12, further comprising: fixedly retaining (530), by the mechanical latch (270, 370), the upper portion of the electromagnetic actuator (140, 240) when the moveable contact (132, 232) is in the second position.

23. The method of claim 22, further comprising: subsequent to fixedly retaining the upper portion of the electromagnetic actuator (140, 240), removing (540) the current from the voice coil (142); manually releasing (550) the mechanical latch (270, 370); and in response to the manual release of the mechanical latch (270, 370), urging (560), by a resilient member, the moveable contact (132, 232) along the first axis from the second position to the first position.