CIRCUIT BREAKER

Description

[0001] The invention relates to a circuit breaker with a mechanical switch incorporated into a main current path. Furthermore, the invention relates to a motor vehicle with a circuit breaker.

[0002] Motor vehicles, such as commercial vehicles, buses, and trucks, are increasingly using one or more electric motors as their primary propulsion, directly providing propulsion. A high-voltage battery is usually used to power the electric motor(s), providing a direct current of between 400 V and 800 V. The electrical currents flowing between the high-voltage battery and the electric motor during operation amount to several tens of amps.

[0003] In the event of a fault, such as a short circuit or an accident, it is necessary to electrically isolate the high-voltage battery from other components of the vehicle, such as the electric motor. This typically involves a circuit breaker, which has a switch integrated into a main current path between the high-voltage battery and the electric motor. The circuit breaker is designed in such a way that if the electrical current carried via the main current path exceeds a certain limit, the switch is activated, thus preventing the flow of electrical current.

[0004] A semiconductor switch, for example, is provided as the switch. However, this causes comparatively high electrical losses during operation, which reduces the efficiency and thus the range of the vehicle.

[0005] Alternatively, a (mechanical) relay is used as a switch. This relay has a fixed contact and a movable contact mounted relative to it. The movable contact is usually connected to a contact bridge, which is driven by an electric coil acting as an electromagnet. This increases the inertia, so that the switch has a comparatively slow switching time. To avoid this, it is possible to use an electric coil with a comparatively high number of turns, but this leads to increased manufacturing costs. This also results in a comparatively high force acting on the contact bridge, which increases the mechanical load.

[0006] WO019990 / 10902 A2 shows a circuit breaker having a PTC element.

[0007] DE 198 51 226 A1 discloses a circuit breaker for interrupting the current flow in a conductor in the event of an overcurrent or short circuit. This switch comprises a contact bridge that contacts the conductor disconnected in this area when current flows, and a magnetically conductive disc that, together with a coil connected to an energy storage device, forms a magnetodynamic drive.

[0008] EP 0 483 591 A2 discloses a low-voltage switchgear comprising a single- or multi-pole contact system with a corresponding number of fixed contacts and movable contacts, a magnetic armature that moves the movable contacts, at least one DC-energized magnetic coil, and a predetermined switching trigger. The magnetic armature operates bistable.

[0009] WO 2009 / 138603 A1 discloses a circuit breaker. It comprises an input line, an output line, at least one static switching device connecting the input line to the output line, and a control circuit connected to the static switch and a device for measuring an electrical property in the output line.

[0010] DE 20 2016 102 682 U1 discloses a circuit breaker for interrupting direct current, in particular in a vehicle's electrical system. This circuit breaker comprises a main current path with a switch and a reed relay for detecting an electrical current flow through the main current path.

[0011] DE 102 44 961 B3 shows a selective circuit breaker. The circuit breaker has a main current path with a main current winding, main contacts, a magnetic release for the main contacts, and a secondary current path with secondary contacts. A switch mechanism for closing or opening the contacts is assigned to the main and secondary contacts.

[0012] US 2,905,792 shows an arc chute design with load-bearing spacers.

[0013] The invention is based on the object of specifying a particularly suitable circuit breaker and a particularly suitable motor vehicle, wherein safety is advantageously increased and / or manufacturing costs as well as load and losses occurring during operation are reduced.

[0014] With regard to the circuit breaker, this object is achieved according to the invention by the features of claim 1 and with regard to the motor vehicle by the features of claim 8. Advantageous further developments and refinements are the subject of the respective subclaims.

[0015] The circuit breaker is primarily used to safeguard, i.e., protect, an electrical line and / or a component, such as a device. In other words, the circuit breaker is either a miniature circuit breaker or a device circuit breaker.

[0016] The circuit breaker has a main current path into which a mechanical switch is incorporated. During operation, an electrical current is carried via the main current path and / or an electrical voltage is applied to it, wherein in the event of a fault, i.e. when protection is required, the electrical current flow via the main current path is in particular intended to be interrupted. Preferably, the main current path is formed at least partially by means of a busbar which is made, for example, from a metal, preferably copper, such as pure copper or a copper alloy, for example brass. Expediently, the circuit breaker has at least two connections by means of which the main current path is connected to other components in the assembled state. The connections can be identical or different from one another and can each be, for example, a screw or plug connection.

[0017] The mechanical switch, which is also referred to simply as a switch in the following, has a fixed contact and a moving contact which is connected to a contact bridge which is movably mounted with respect to the fixed contact. Consequently, the moving contact is also movably mounted to the fixed contact, namely by means of the contact bridge. For example, the moving contact is welded to the contact bridge and, for example, is formed integrally with it. Alternatively, the moving contact is made of a different material than the contact bridge. For example, the fixed contact is held in place and its position is thus rigid. Alternatively, the position of the fixed contact is also variable and is movably mounted, for example, by means of a further bridge or other mechanical means.

[0018] The circuit breaker preferably comprises a housing, which is made, for example, from a plastic, and within which both the fixed contact and the moving contact are arranged. The contact bridge is expediently mounted on the housing by means of a hinge or other bearing, for example a plain bearing. In a further development, a guide is formed by the housing itself, by means of which the contact bridge is mounted. The fixed contact is particularly preferably arranged rigidly on the housing or at least immovably with respect to the housing, which simplifies construction. For example, the contact bridge is mechanically connected directly to a rigid (if any) busbar of the main current path and thus in particular to one of the possible connections. For movable mounting, the contact bridge is expediently pivotably mounted.

[0019] However, the contact bridge is particularly preferably formed by a stamped and bent part or other metal strip and mounted for transverse displacement. A further moving contact is expediently connected to the contact bridge. A further fixed contact is expediently associated with the further moving contact, and when the contact bridge is moved, mechanical contact is suitably established or eliminated between the moving contact and the fixed contact, as well as between the further moving contact and the further fixed contact, particularly depending on the direction of movement of the contact bridge.

[0020] In summary, when there is mechanical contact between the moving contact and the fixed contact, the mechanical switch is closed and electrically conductive. When the moving contact is separated from the fixed contact by the contact bridge, the switch is open and electrically non-conductive. Thus, depending on the position (state) of the contact bridge, the switch is either in the open or closed state, or, for example, a position in between. In this position, the distance between the moving contact and the fixed contact is not maximum, but there is no mechanical connection between them. For example, the switch includes a locking mechanism or other latching device by means of which the contact bridge is locked in the open or closed state. In other words, the switch is thus designed to be monostable or bistable.If the locking mechanism only occurs in one of the states, for example, the closed or open state, it is necessary to apply force to move the contact bridge, i.e., to actuate the switch, thus preventing unintentional actuation of the (mechanical) switch, for example, due to vibration of the circuit breaker.

[0021] The circuit breaker further comprises a drive that is operatively connected to the contact bridge. By operating the drive, it is possible to move the contact bridge from at least one of the two positions to the other, i.e., closed or open. In other words, by operating the drive, it is possible to switch the circuit breaker.

[0022] The drive has a first drive unit and a second drive unit, which in particular can be operated or are operated separately from one another, or which are at least active depending on different conditions / circumstances, such that the contact bridge is moved. The first drive unit is energized by means of a control circuit. In other words, the control circuit is provided to supply the first drive unit, by means of which the first drive unit is thus powered. Particularly preferably, the control circuit is galvanically isolated from the main current circuit, such that in the event of a fault in the main current path, any feedback to the control circuit is prevented. Thus, the first drive unit can be energized essentially without disruption. The control circuit is fed, for example, via the main current path, in particular by means of a transformer.In a further development, the control circuit is powered by a separate power source, and the circuit breaker has, in particular, additional connections for this purpose, which are incorporated, for example, into the circuit breaker's housing. The control circuit expediently has a voltage level that differs from the voltage level, or at least the electrical potential, that is carried by the main current path. In particular, the control circuit is operated with a lower electrical voltage. This simplifies the design of the circuit breaker.

[0023] The second drive unit is (electrically) connected in parallel to a resistance element introduced into the main current path. This makes it possible to energize the second drive unit using the electrical current conducted via the main current path. This occurs in particular when the electrical voltage drop across the resistance element is greater than the electrical voltage drop across the second drive unit. The resistance element is expediently selected / constructed / designed such that, under normal circumstances, the electrical voltage drop across the resistance element is lower than the electrical voltage drop across the second drive unit, preferably many times lower. Thus, the electrical current conducted via the main current path is essentially conducted solely by means of the resistance element.

[0024] In the event of a fault, however, the voltage drop across the second drive unit is preferably lower than the voltage drop across the resistance element, so that the second drive unit is energized. Thus, in the event of a fault, for example, an overload or overcurrent, the position of the contact bridge is influenced by the second drive unit.

[0025] The two drive units make it possible to operate the circuit breaker regardless of the fault, thus expanding its range of applications. The force provided by the first drive unit is expediently comparatively low, so that the switching time during its operation is comparatively slow, while mechanical stress is reduced. This makes it possible to use a comparatively low-power first drive unit, thus reducing manufacturing costs. If a fault occurs, the first drive unit can initiate movement of the contact bridge and thus open the mechanical switch. However, the second drive unit also provides support.The second drive unit is expediently designed such that, in the event of a fault, a comparatively large force is exerted, which is in particular greater than the force provided by the first drive unit. As a result, the circuit breaker has a comparatively short switching time, which increases safety. The provision of the increased force is possible in particular due to the comparatively large electrical current carried by the main current path. In this case, during normal operation, essentially no electrical current is preferably carried by the second drive unit, and in this case the electrical current is expediently carried only or at least predominantly by means of the resistance element. Thus, any (electrical) losses occurring during (normal) operation are comparatively low.Furthermore, the two drive units allow the mechanical switch to open even if one of them malfunctions, thus increasing safety. In other words, redundancy is created, allowing safe disconnection even if the control circuit fails, for example.

[0026] In summary, the two drive units make it possible to exert a comparatively large force on the mechanical switch, causing it to accelerate comparatively significantly. As a result, the switching time of the mechanical switch is also accelerated, suitably in the event of a fault. However, it is also possible to actuate the mechanical switch with just one of the drive units, in particular the first drive unit or the second drive unit, so that electrical and mechanical stress as well as energy consumption are reduced. As a result, the application range of the circuit breaker is expanded, and it is used, for example, to interrupt the electrical current during normal operation, whereby only one of the drive units is energized. In the event of a fault, however, both drive units are used to actuate the switch. This reduces the number of components required.Due to the mechanical switch, the electrical resistance of the circuit breaker is comparatively low, so that no or only comparatively low electrical losses occur during operation. The circuit breaker also enables galvanic isolation, thus increasing safety. The resistance element ensures that the second drive unit is not continuously supplied with current, which also reduces electrical losses.

[0027] The circuit breaker is preferably designed to interrupt direct current and is, for example, merely unidirectional or, more preferably, bidirectional. Suitably, the circuit breaker has a further main current path, with an electrical voltage being present between the main current path and the further main current path during operation. For example, the further main current path is electrically connected to ground, or the circuit breaker has a further mechanical switch that is incorporated into the further main current path and actuated by means of a corresponding drive. This further increases safety. Particularly preferably, the maximum electrical voltage that can be switched by means of the circuit breaker is greater than 100 V, 200 V, or 500 V. For example, the maximum electrical voltage that can be switched by means of the circuit breaker is less than 3500 V or 3000 V. The circuit breaker is suitable, in particular provided and configured, for this purpose.For example, the circuit breaker is intended for switching an electrical voltage of 1000 V and / or switching an electrical current of several 100 A, for example 200 A, 400 A, 600 A or 800 A. The circuit breaker is expediently suitable for this purpose, preferably configured.

[0028] The circuit breaker is particularly preferably used in a motor vehicle, in particular in an on-board electrical system by means of which an electrical direct current is carried. The circuit breaker is particularly preferably a component of a high-voltage on-board electrical system of the motor vehicle and serves in particular to protect a high-voltage battery and / or an electric motor of a motor vehicle, by means of which in particular a drive is provided. The motor vehicle is, for example, a ship, boat or aircraft. However, the motor vehicle is particularly preferably land-based and, for example, rail-guided. In this case, the motor vehicle is, for example, a railcar, a locomotive, a train or a tram. Alternatively, the motor vehicle can be moved independently of rails or the like. Expediently, the motor vehicle is a passenger car (car) or particularly preferably a commercial vehicle, such as a bus or a lorry (truck).Alternatively, the circuit breaker is intended for industrial use and, for example, is a component of an industrial plant when installed.

[0029] The circuit breaker suitably comprises a manual switch that is operatively connected to the mechanical switch, preferably to the contact bridge. By means of the manual switch, it is suitably possible to place the mechanical switch in a specific state, for example, in the closed state or the open state. For example, placing the mechanical switch in the other state is not possible due to a mechanism arranged between the mechanical switch and the manual switch. However, it is particularly preferably possible to place the mechanical switch in both the closed and the open state by means of the manual switch. In summary, the circuit breaker is thus also manually operable, and it is thus particularly possible to reset the circuit breaker.Alternatively or in combination, it is possible, for example, to manually prevent operation of a motor vehicle using the circuit breaker.

[0030] The circuit breaker suitably includes an additional mechanism that acts on the mechanical switch and by means of which the mechanical switch can be reset. In particular, the drive or another drive is provided for this purpose. This also enables resetting of the circuit breaker after it has tripped, so that it is once again live. This advantageously does not require any manual intervention.

[0031] For example, the contact bridge is subjected to a force, such as a spring force, and this force is held in a specific position, for example, by a latch. The drive acts specifically on the latch, so that when the drive is energized, the latch is released. As a result, the contact bridge is moved by the additional force acting on it. As a result, it is not necessary to exert a comparatively large force by means of the drive, yet the mechanical switch is actuated relatively quickly.

[0032] However, it is particularly preferred that the drive is mechanically coupled to the contact bridge. In other words, during operation the contact bridge is moved due to the force exerted by the drive. This reduces the number of components required. In a further development, the contact bridge is latched, and the drive acts on both the latch and the contact bridge. Advantageously, a further component is provided by means of which a force is also exerted on the contact bridge, such as the spring. In this way, the actuation of the mechanical switch, i.e. the adjustment of the contact bridge, takes place both by means of the drive and by means of the further component, such as the spring, so that the switching speed is further increased. The force required by the drive is reduced, so that it can be designed to be comparatively small.However, the force applied by the drive is also used to move the contact bridge, so that the provided force is used comparatively efficiently. In an alternative or further development, one of the drive units acts on the latch, and the other drive unit acts on the contact bridge and is thus coupled to it.

[0033] For example, the contact bridge is rigidly attached to a transversely mounted rod driven by the drive. Preferably, however, the contact bridge is also transversely mounted on the rod, with two end stops expediently being provided to limit the movement of the contact bridge relative to the rod. This makes it possible to move the contact bridge between these two end stops so that, for example, in the event of contact burn-off or high manufacturing tolerances, there is still secure, full-surface mechanical contact between the moving contact and the fixed contact when the circuit breaker is closed. In particular, one of the end stops is designed in such a way that the contact bridge can still be moved from the closed state by means of the drive. In other words, the distance between the end stops is preferably less than the travel range of the drive.Because the end stop remains, the contact bridge can also be moved regardless of the current state of the drive. This means that when a comparatively high electrical current flows, the contact bridge is also lifted due to the so-called Holm constriction force, separating the moving contact from the fixed contact. This occurs, for example, before the contact bridge is moved by the drive. In other words, in this case, both the force applied by the drive and the forces due to the existing magnetic fields act on the contact bridge, increasing the switching speed. A spring is preferably arranged between one of the end stops and the contact bridge, by means of which spring the contact bridge is moved into a specific position when no other forces are acting.

[0034] For example, the second drive unit is connected directly to the main current path. However, the second drive side is particularly preferably connected to the main current path via a rectifier. This makes it possible to operate the circuit breaker bidirectionally, simplifying the construction of the second drive unit. The rectifier is preferably designed to be passive and, in particular, has a plurality of diodes. The rectifier is expediently designed as a bridge rectifier, in particular as a B4 rectifier. This, on the one hand, keeps manufacturing costs comparatively low. On the other hand, no control or the like is required for the operation of the rectifier, which increases robustness.

[0035] In particular, the rectifier also serves to determine when the second drive unit is energized. This is advantageously only energized when the voltage drop across the resistance element is greater than the voltage drop across the series circuit of the rectifier and the second drive unit. This reduces the requirements for the resistance element, and makes it possible to use a resistance element with comparatively high manufacturing tolerances. The voltage required to operate the rectifier ensures that the commutation of the current from the resistance element to the second drive unit only occurs in the event of a fault. This further increases operational reliability and reduces manufacturing costs.

[0036] Alternatively, or in a particularly preferred combination, a Zener diode is connected between the second drive unit and the main current path. If a rectifier is present, the Zener diode is expediently located between the rectifier and the second drive unit. Thanks to the Zener diode, current is only carried by the second drive unit when the electrical voltage drop across the resistance element reaches at least the breakdown voltage of the Zener diode, optionally in conjunction with the electrical voltage required by the rectifier. Thus, the Zener diodes make it possible to set the threshold of the electrical current carried via the main current path at which the second drive unit is actuated. As a result, only the Zener diode needs to be adapted to the current application, whereas identical parts can be used elsewhere.This reduces manufacturing costs.

[0037] Alternatively, or in combination with the Zener diode, a thermistor is electrically connected between the second drive unit and the main current path, with the thermistor being thermally connected, for example, to the resistance element or other component of the main current path. Thus, if the thermistor (NTC) is heated due to a comparatively large electrical current carried by the main current path, its electrical resistance decreases, causing the second drive unit to conduct current and, consequently, the mechanical switch to open.

[0038] In a further alternative, a second switch is connected between the second drive unit and the main current path. The second switch is controlled in particular by means of a second control unit, wherein the second control unit is energized in particular based on the electrical voltage dropping across the resistance element. Alternatively, the second control unit is energized, for example, by means of the control circuit or always via the main current path. The second switch is closed in particular when a fault occurs, which is detected, for example, by the second control unit. Certain sensors are evaluated for this purpose. For example, the second switch is closed when the first drive unit is energized, so that in this case the second drive unit is also energized. Otherwise, for example, the second switch always remains open.

[0039] Particularly preferably, a second current sensor is provided, which is, for example, inserted between the second drive unit and the main current path. In other words, the electrical current conducted by the second drive unit is measured by the second current sensor. The second current sensor is, for example, a shunt or comprises one. Suitably, the second switch is actuated depending on the electrical current measured by the second current sensor.

[0040] The second switch is suitably opened when the electrical current detected by the second current sensor exceeds a further limit value. Thus, by actuating the second switch, it is ensured that damage to the second drive unit is avoided, even in the event of a comparatively extensive fault. In this case, the second drive unit is shut down. However, it is still possible to energize the first drive unit, so that the mechanical switch is opened by this. Consequently, the flow of electrical current is still interrupted by the protective switch. Particularly preferably, the second control unit is energized by means of the electrical current flowing between the main current path and the second drive unit. Thus, the second control unit is only energized when the second drive unit is also energized.This reduces the amount of energy required to operate the circuit breaker. However, the second control unit still allows the second drive unit to be protected.

[0041] The circuit breaker preferably comprises a control unit by means of which the first drive unit is energized. Thus, the control unit is also fed by the control circuit and consequently energized via it. In this case, the control unit is particularly designed such that it detects a fault and that, in the event of a fault, the first drive unit is energized or at least actuated in such a way that the switch is opened, i.e. the moving contact is spaced apart from the fixed contact. The control unit is particularly suitable, provided, and configured for this purpose. Alternatively or in combination with this, the control unit is connected to other components in terms of signaling in the assembled state and expediently has a corresponding connection for this purpose. For example, the control unit has a connection to a possible bus system of the possible motor vehicle.The circuit breaker suitably serves to provide functional safety, and the control unit is designed accordingly. In particular, it is possible to implement various safety functions using the circuit breaker, and the control unit is, for example, certified accordingly or at least stores the different control types for the first drive unit to provide functional safety. In one development, the control unit is used, in particular, to control and / or regulate the current for supplying power to the first drive unit, using, for example, pulse width modulation. In this way, it is possible to set a switching time for the first drive unit.

[0042] For example, the circuit breaker also includes the second control unit, by means of which, in particular, the second drive unit is also controlled or at least monitored. The second control unit is powered, for example, via the control circuit or via the main current path. Alternatively, the second drive unit is controlled or monitored by the control unit. However, it is particularly preferred that the second drive unit is not controlled / regulated, which increases robustness.

[0043] The control unit has, for example, a trigger, which is particularly designed in the manner of a switch. The trigger is, for example, arranged in direct proximity or in mechanical contact with the main current path or, for example, is a component of the main current path. In particular, the electrical current carried via the main current path and / or the electrical voltage applied thereto is detected by means of the trigger, and the drive, in particular the first drive unit, is energized depending thereon. The trigger is, for example, magnetically designed and is, for example, a reed relay or at least comprises one. Alternatively, the trigger is hydraulically designed or, particularly preferably, is a thermal trigger, such as a bimetallic snap disk, another bimetallic element, a PTC thermistor, or a NTC thermistor.

[0044] For example, the control unit is formed by the trigger, and the trigger is expediently electrically connected in series with the first drive unit. Alternatively, the respective trigger is designed merely as a signal generator and is connected to other components of the control unit for signaling purposes. The control unit itself is implemented, for example, using analog components or comprises a microcontroller.

[0045] Particularly preferably, the control unit is signal-connected to a current sensor of the main current path. The current sensor is suitable, in particular provided and configured, for measuring the electrical current carried by the main current path. The control unit is implemented, in particular, by means of a microcontroller, or at least comprises this, or has several discrete, analog components. For example, the current sensor comprises an electrical coil or, for example, a shunt that is introduced into the main current path.

[0046] Depending on the electrical current value detected by the current sensor, the first drive unit is expediently energized by the control unit, thereby actuating the contact bridge and consequently the mechanical switch. Such a configuration increases flexibility, and it is particularly possible to use the circuit breaker in a variety of applications. Consequently, the mechanical switch can also be switched in the event of a fault, without the second drive unit influencing the switching state of the switch. Consequently, the range of applications for the circuit breaker is expanded.

[0047] Particularly preferably, the circuit breaker comprises, alternatively or in combination, at least one or more electrical voltage sensors, by means of which, for example, the electrical voltage drop across the mechanical switch, the electrical voltage drop across any current sensor, the electrical voltage drop across the resistance element, the electrical voltage drop across the series connection of the mechanical switch and the resistance element, optionally in conjunction with any current sensor, the electrical voltage drop across the first and / or drive unit and / or the electrical voltage present between the main current path and any further main current path can be measured. Preferably, the control unit energizes the first or second drive unit depending on the respectively detected values.Suitably, the control unit evaluates the temporal change in the electrical current or voltage and operates the drive, in particular the first drive unit, depending on this change. This also enables the detection of a wide variety of faults, thus increasing safety.

[0048] Particularly preferably, the control unit comprises an energy storage device for supplying power to the first drive unit. In particular, the energy storage device is charged by means of the control circuit during operation. This enables the drive, in particular the first drive unit, to be operated even if the power supply via the control circuit fails, which is why safety is always guaranteed. Particularly preferably, the energy storage device is designed as a capacitor which is, for example, electrically connected in parallel to the first drive unit or other components of the control unit, such as any microcontroller. The capacitor thus also compensates for any voltage fluctuations in the control circuit, which is why the first drive unit or the other components of the control unit are protected and safe operation is possible. In other words, the capacitor dampens short-term current jumps.

[0049] For example, the control unit comprises a charge pump, a voltage multiplier, or another component that makes it possible to charge the energy storage device to a higher electrical voltage than that provided by the control circuit. In this way, the energy storage device stores a comparatively large amount of electrical energy during operation, so that in the event of a control circuit failure, other components of the control unit can also be supplied with power, or an increased amount of electrical energy is provided for operating the drive, in particular the first drive unit, so that the mechanical switch can be reliably actuated.

[0050] For example, the two drive units operate according to the same principle or different principles (modes of operation / principles of operation). For example, at least one of the drive units comprises an eddy current drive, an eddy current coil, a reluctance drive, a reluctance coil, a piezo actuator, or the respective drive unit is formed using a combination of these. Preferably, the two drive units are structurally identical or at least constructed according to the same principles of operation, which simplifies construction. It is also possible to use at least partially identical parts. Alternatively, the construction and / or modes of operation of the two drive units differ, thus increasing robustness and safety. Particularly preferably, the drive comprises a "moving magnet actuator," which is also referred to below in particular simply as an actuator, and by means of which the two drive units are formed.

[0051] The "moving magnet actuator" (“moving magnet actuator”) has a permanent magnet that is mounted for movement. For example, the permanent magnet is mounted for rotational movement or, more preferably, for linear movement. The permanent magnet is connected to the contact bridge or at least operatively connected to it, so that when the permanent magnet moves, the contact bridge is preferably moved. In addition, each drive unit has one or more electrical coils that are energized when the respective drive unit is actuated, creating a magnetic interaction between them and the permanent magnet. The electrical coils are held stationary.

[0052] Because the electrical coil(s) are held stationary, the design is simplified, and, with the exception of the components required for bearings, no further moving components or electrical connections are required between the moving components, namely the permanent magnet, and the stationary components of the moving magnet actuator. This also reduces friction. Since the number of moving components of the moving magnet actuator, in particular only the permanent magnet, is comparatively small, and these are comparatively lightweight, the dynamics of the actuator are comparatively high. This reduces inertia when actuating the contact bridge and thus when actuating the switch. As a result, the circuit breaker enables comparatively fast switching, thus increasing safety.

[0053] For example, the actuator is designed to be rotary or, particularly preferably, linear. InIn this case, each drive unit has two electrical coils arranged concentrically on a (common) axis, which are spaced apart from one another along the axis, and between which the permanent magnet is arranged, the two poles of which are opposite one another with respect to the axis and which is mounted so as to be movable along the axis. The two electrical coils of each drive unit are energized simultaneously, in particular during the respective operation, and are, for example, electrically connected in series or, more preferably, electrically connected in parallel. The wiring of the electrical coils is such that, when they are energized, a magnetic field is created by means of the electrical coils, which interacts with the magnetic field of the permanent magnet in such a way that the latter is pulled along the axis towards one of the electrical coils of the respective drive unit and pushed away from the other electrical coil of the same drive unit.Consequently, a comparatively large force acts on the permanent magnet, which is why the dynamics are further increased.

[0054] In particular, each of the electrical coils of one of the drive units is surrounded by one of the electrical coils of the other drive unit, and these are in particular arranged concentrically with one another. This provides a comparatively compact "moving magnet actuator." Particularly preferably, the electrical coils of the second drive unit have a comparatively low number of turns, which is expediently less than 50, 30, or 20. This also makes it possible to use a comparatively large cross-section for the electrical conductor of the electrical coils of the second drive unit, so that the current-carrying capacity is increased. As a result, even in the event of a comparatively large overcurrent, which is carried via the main current path and thus also via the electrical coils of the second drive unit, damage to the latter is ruled out.Particularly preferably, one of the electrical coils of the second drive unit surrounds one of the electrical coils of the first drive unit.

[0055] Particularly preferably, the "moving magnet actuator" comprises a (magnetic) short-circuit plate or the like, by means of which the permanent magnet is held in a specific position when no current is applied to the electrical coil(s). For example, in this case, the permanent magnet rests against the short-circuit plate or, particularly preferably, is always spaced from it. The short-circuit plate is expediently made of a ferromagnetic material, such as iron, which reduces manufacturing costs. Due to the short-circuit plate, the permanent magnet is stabilized in one position, especially when the switch is closed. Consequently, the mechanical switch is designed to be at least monostable or bistable.

[0056] In a further alternative, only one of the drive units is formed by the actuator. The other drive unit is separate from it, for example, and is designed in particular as an eddy current drive or reluctance drive.

[0057] In particular, the resistance element is designed to be controllable so that the (ohmic) resistance realized by the resistance element can be adjusted. The resistance element comprises an additional switch and is formed, for example, by means of the latter. The additional switch is, for example, a mechanical switch, such as a relay, or particularly preferably a semiconductor switch. Two such additional switches are expediently provided, which are connected, for example, in antiparallel or anti-serial to one another, so that the circuit breaker is designed to be bidirectional. The respective semiconductor switch is, for example, a field-effect transistor, such as a MOSFET, or a bipolar transistor, such as an IGBT, IGCT, a thyristor, or a GTO.

[0058] The additional switch or the interconnection of the two additional switches is controlled by an additional control unit. The additional control unit detects, in particular, the fault and, depending on this, the additional switch or switches are actuated. As a result, the electrical resistance provided by the resistance element increases essentially suddenly, which is why the electrical current is commutated from the resistance element to the second drive unit, such that the mechanical switch is opened. The additional control unit is energized, in particular, by means of the control circuit, so that it operates in the main current path regardless of the fault. Alternatively, the additional control unit is controlled, for example, based on the signal transmitted via the additional switch or switches.the electrical voltage generated by the connection of the additional switches is energized, which only occurs in the event of a fault.

[0059] Expediently, an overvoltage protector is connected in parallel with the resistance element and thus also with the additional switch(es), comprising, for example, a varistor and / or a circuit of Zener diodes. For example, the overvoltage protector is implemented using so-called "active clampings" of the additional switch(es) designed as semiconductor switches. The overvoltage protector protects the additional switch(es) so that their destruction due to a comparatively high applied electrical voltage, in particular due to the actuation of the mechanical switch, is prevented. In this way, the overvoltage protector also limits the electrical voltage applied to the second drive unit and to any rectifier, thus preventing damage to them.Due to the use of the additional switch as a resistance element, a controlled adjustment of the commutation of the electrical current from the resistance element to the second drive train is possible, so that operation of the second drive unit is possible even in the event of a large number of different fault cases.

[0060] Particularly preferably, the circuit breaker comprises a second additional switch, which is in particular connected in parallel to the additional switch. Suitably, the additional switch and the second additional switch are designed as semiconductor switches, and there are preferably two additional switches and two second additional switches, which are each connected anti-parallel or anti-serial to one another, thus enabling bidirectional operation of the circuit breaker. Preferably, the additional switch(es) have a comparatively low internal resistance, so that during normal operation the electrical current carried by the main current path is conducted by means of them. For example, the additional switches have comparatively poor switching behavior, which is why comparatively inexpensive semiconductor switches can be used for this purpose.

[0061] The second additional switches, for example, exhibit comparatively good switching performance and are particularly suitable for switching comparatively high electrical voltages and / or high electrical currents. For example, the second additional switches exhibit a comparatively high internal resistance, so that comparatively inexpensive semiconductor switches can also be used for this purpose. Thus, both the additional switches and the second additional switches are comparatively inexpensive, but they differ from one another.

[0062] Due to the comparatively high internal resistance of the second additional switches, the electrical current is not carried by them during normal operation. Rather, the electrical current is carried by the additional switches, which is why electrical losses are comparatively low. In the event of a fault, the additional switches with the comparatively low internal resistance are expediently opened first, which preferably takes place using the additional control unit that is suitable, in particular provided and configured for this purpose. As a result, the electrical current initially commutates to the second additional switches, whereby the electrical losses increase. Subsequently, the second additional switches are actuated, which can also switch the comparatively large electrical current flow and the high electrical voltage without damage. As a result, the electrical current commutates to the second drive unit, which is thus actuated.

[0063] For example, a second additional control unit is assigned to the second additional switches, or the second additional switches are also controlled by means of the additional control unit. If the second additional control unit is present, it is powered in particular by the electrical voltage dropped across the second additional switches. Particularly preferably, an overvoltage protector is connected in parallel to the second additional switch(es) so that an electrical overvoltage at the second additional switches is avoided. Alternatively, only a single corresponding overvoltage protector is present, which is assigned to the additional switches and the second additional switches.

[0064] In an alternative to this, the resistance element used could be, for example, a varistor, an ohmic resistor, a fuse, a variable resistor, a non-linear resistor, the internal resistance of an electrical component such as a current sensor, a shunt, an electrical coil, a diode, or a PTC thermistor. In a further alternative, a MOSFET or IGBT is used as the resistance element, which also exhibit an increase in electrical resistance with increasing temperature. However, the resistance element at least comprises one of the previously mentioned components and, for example, comprises an interconnection of different ones. Consequently, it is possible to use a variety of different components, including comparatively inexpensive ones. It is also possible to use an existing component as a resistance element that performs a different function.This means that manufacturing costs are not increased. Furthermore, without appropriate control, such components generate increasing voltage as the electrical current conducted through the main current path increases, thus commutating the electrical current to the second drive unit. This increases robustness. However, essentially only the second drive unit operates in the event of an electrical overcurrent.

[0065] For example, the circuit breaker is formed solely by the main current path with the resistance element, the mechanical switch, possibly the control unit, and the drive. Particularly preferably, however, the circuit breaker comprises a fuse. For example, the fuse is connected in parallel to the mechanical switch and is designed in particular to trip if the mechanical switch malfunctions. This increases safety. Particularly preferably, however, the fuse is connected in parallel to the mechanical switch. When the mechanical switch is closed, the electrical current flows through it, and essentially no electrical voltage is applied to the fuse. When the mechanical switch is actuated, i.e., when it is opened, the electrical current commutates to the fuse, so that no arc is created between the moving contact and the fixed contact.Due to the (electrical) current flowing through the fuse, the fuse is expediently blown, thus interrupting the current flow through the fuse. At this point, the moving contact is already sufficiently far away from the fixed contact due to the drive that an arc is no longer generated. As a result, the electrical current flow through the circuit breaker is terminated. In summary, the electrical current is interrupted relatively safely, preventing the formation of an arc, which would continue to conduct electrical current.

[0066] For example, the fuse is designed in such a way that it can carry the electrical current occurring during normal operation, meaning that the fuse does not trip in this case. Preferably, however, the fuse is dimensioned such that it trips when the switch is opened under normal conditions, i.e. when there is no fault. In this way, the switching behavior of the circuit breaker is accelerated in the event of a fault. In addition, this makes it possible to use a comparatively inexpensive fuse that is only designed for a low nominal current and, in particular, is designed as a fast-acting fuse. In this case, the circuit breaker is actuated, i.e. tripped, by actuating the drive, which can be adjusted relatively precisely.The fuse only serves to conduct electrical current for a short time, preventing or at least shortening the formation of an arc in the mechanical switch. This makes it possible to use fuses with a comparatively large fault tolerance, thus reducing manufacturing costs. The mechanical switch allows for relatively precise adjustment of the circuit breaker, i.e., when it will trip.

[0067] Alternatively, or in combination with this, a semiconductor switch is connected in parallel with the mechanical switch. In a further development, the semiconductor switch is connected in parallel with the series circuit comprising the mechanical switch and the resistance element, i.e. also with the series circuit comprising the second drive unit and the mechanical switch. In particular, a MOSFET, an IGBT, an IGCT, or a GTO is used as the semiconductor switch. The semiconductor switch is supplied, for example, by a separate voltage supply, for example via the control circuit. Alternatively, the semiconductor switch is supplied by the electrical voltage dropped across the (open / opening) mechanical switch or the second drive unit.In particular, the wiring is such that when the mechanical switch is opened and / or when the second drive unit is operated, the semiconductor switch becomes live, so that no arc is formed in the mechanical switch. For example, any current supply to the second drive unit is also terminated. Consequently, the semiconductor switch also limits the maximum electrical voltage applied to the second drive unit, thus protecting it. After the mechanical switch is opened, the semiconductor switch, in particular, is also opened, so that the electrical current is interrupted.

[0068] During normal operation, the semiconductor switch is preferably not conducting current, i.e., when the mechanical switch is closed, so that no electrical losses occur in the semiconductor switch, thus improving efficiency. Preferably, a separate control unit is assigned to the semiconductor switch, or it is operated, for example, by means of the control unit that also supplies current to the drive, in particular the first drive unit. This reduces the number of required components.

[0069] Particularly preferably, the circuit breaker has a further semiconductor switch which is connected in series with the semiconductor switch, the mechanical switch being bridged by means of the series connection. The two semiconductor switches are expediently connected in anti-series. Alternatively, the two semiconductor switches are connected in anti-parallel. As a result, the circuit breaker can be operated bidirectionally. For example, the two semiconductor switches are structurally identical to one another or different. In a further alternative, instead of the further semiconductor switch, a diode is electrically connected in series with the semiconductor switch. In a further development, the mechanical switch is bridged by a circuit which has the semiconductor switch which is electrically connected between two pairs of two diodes each, which are each connected in anti-parallel to one another.In other words, a B4 bridge circuit is present, which, in particular, serves as a rectifier. The diodes ensure that the direction of current flow through the semiconductor switch is always the same, regardless of the direction of current flow through the main current path. Thus, the circuit breaker is bidirectional, with only a single semiconductor switch being present.

[0070] Alternatively, or in combination with this, a varistor is expediently connected in parallel to the semiconductor switch(es) or the series circuit. This varistor, in particular, prevents electrical overvoltage at the semiconductor switch or the circuit, which could lead to damage. In a further alternative, the circuit breaker comprises several thyristors connected in antiparallel to one another, by means of which the mechanical switch is bypassed.

[0071] Particularly preferably, the mechanical switch comprises an arcing chamber, within which the contact bridge is expediently arranged. For example, the arcing chamber comprises several arcing plates and / or a permanent magnet, by means of which any arc that may arise between the moving contact and the fixed contact when the mechanical switch is actuated is extinguished.

[0072] The quenching chamber preferably comprises quenching strips stacked one above the other in a stacking direction, i.e. a plurality of quenching strips, in particular at least two quenching strips and suitably fewer than 100 quenching strips. The number of quenching strips is preferably between 5 and 80, between 8 and 50 or between 10 and 30. Suitably, the number of quenching strips is less than or equal to 20. The quenching strips are flat and thus each extend in only one plane. Perpendicular to this plane, the extent of each quenching strip is reduced, and the extent, which is also referred to as the thickness, is expediently less than or equal to 2 mm, 1.5 mm or 1 mm. The quenching strips are expediently arranged perpendicular to the stacking direction and parallel to one another. The projections of the quenching strips parallel to the stacking direction preferably overlap at least partially, preferably completely.This provides a comparatively compact extinguishing chamber.

[0073] The quenching strips are made of a ceramic which is in particular electrically non-conductive and preferably thermally conductive. An oxide ceramic such as an aluminum oxide ceramic (AlO3) is particularly preferably used as the ceramic. For example, the quenching chamber comprises a drive element for driving any arc which may arise during a switching operation of the mechanical switch to or between the quenching strips. In one development, a choke or other electrical coil is electrically connected in parallel with the resistance element, by means of which choke or other electrical coil is particularly limited in relation to the resistance element. In one development, the choke or the electrical coil is electrically connected in series with any semiconductor switch, by means of which semiconductor switch the series circuit comprising the mechanical switch and the resistance element is bridged. The choke orAn electric coil is used as the driving element, which moves the arc. In other words, it is a blowout field coil.

[0074] During operation, the arc is not partially captured by the arc quenching strips, resulting in multiple partial arcs, due to the arc quenching strips' electrically insulating properties. Rather, the arc is deformed, specifically bent, due to the arc quenching strips' electrically insulating properties, so that one part of the arc is extended. Due to the increased arc length and the resulting higher required electrical voltage, it is possible for the arc to extinguish. Thus, when extinguished, the arc reaches a length that could otherwise only be achieved with an enlarged arc chamber.

[0075] In addition, the quenching strips cool the arc, specifically the plasma required to form the arc. As a result, the electrical voltage required to maintain the arc also increases, and when the arc has cooled sufficiently, the arc is extinguished. The thermal conductivity of the quenching strips ensures efficient heat removal from the area of ​​the quenching strips where the heat is transferred from the arc to the respective quenching strip. This further improves the cooling effect, so that the arc is reliably extinguished even with a reduced arc chamber size. In addition, because of the separate quenching strips, any mechanical stress that develops as a result of this is limited to the individual quenching strips, even if they heat up irregularly.Therefore, even with a comparatively large temperature difference between the individual extinguishing strips, no mechanical stress develops between them, which could lead to destruction. As a result, stability and operational reliability are increased.

[0076] The motor vehicle is, for example, land-based and, for example, a passenger car (car). However, the motor vehicle is particularly preferably a commercial vehicle, such as a bus or, more preferably, a truck (lorry). The motor vehicle has a high-voltage electrical system, by means of which, in particular, a direct voltage between 400 V and 800 V is carried. The motor vehicle also comprises a low-voltage electrical system, by means of which, expediently, a direct voltage of 12 V, 24 V, or 48 V is carried. The low-voltage electrical system is used, in particular, to supply power to auxiliary units of the motor vehicle, by means of which, for example, comfort functions or the like are provided. The high-voltage electrical system is used, in particular, to supply power to a main drive, which expediently has an electric motor.In this case, the main drive is preferably electrically connected to a high-voltage battery via the high-voltage electrical system, which supplies the high-voltage electrical system. The low-voltage electrical system is supplied, for example, via a transformer from the high-voltage electrical system or via a separate battery.

[0077] The motor vehicle comprises a circuit breaker with a mechanical switch incorporated into a main current path, which switch has a fixed contact and a moving contact connected to a contact bridge movably mounted thereto. The circuit breaker further comprises a drive operatively connected to the contact bridge and comprising a first drive unit and a second drive unit. The first drive unit is energized by means of a control circuit, and the second drive unit is connected in parallel with a resistance element incorporated into the main current path. Consequently, the second drive unit can be energized by means of the main current path, namely when the electrical resistance of the resistance element is greater than the electrical resistance of the second drive unit.

[0078] The control circuit is electrically connected to the low-voltage electrical system and is thus powered by the low-voltage electrical system. The high-voltage electrical system contains the main current path of the circuit breaker, which thus forms part of the high-voltage electrical system and is integrated into it. Consequently, the mechanical switch and the first drive unit are at different electrical potentials. When the circuit breaker is activated, the high-voltage electrical system is disconnected, at least partially preventing the flow of electrical current through it. Furthermore, the invention also relates to the use of such a circuit breaker for protecting a high-voltage electrical system of a motor vehicle

[0079] The further developments and advantages explained in connection with the circuit breaker can also be transferred to the motor vehicle and vice versa.

[0080] In the following, exemplary embodiments of the invention are explained in more detail with reference to a drawing. In the drawings: Fig. 1 schematically shows a motor vehicle with a circuit breaker, Fig. 2 a simplified circuit diagram of the circuit breaker, which includes a "moving magnet actuator" with two drive units, and Fig. 3 schematically shows the "moving magnet actuator" in a sectional view, Fig. 4 -6 according to Fig. 2 each of an alternative embodiment of the circuit breaker, and Fig. 7 perspective view of an arcing chamber of the mechanical switch.

[0081] Corresponding parts are provided with the same reference numerals in all figures.

[0082] In Figure 1A simplified schematic representation of a motor vehicle 2 in the form of a lorry is shown. The motor vehicle 2 has a plurality of wheels 4, by means of which contact is made with a road surface (not shown in detail). At least one of the wheels 4 is driven by a main drive 6, which comprises one or more electric motors. In other words, the motor vehicle 2 is designed either as a hybrid motor vehicle or as an electric vehicle.

[0083] The main drive 6 is connected to a high-voltage battery 10 via a high-voltage electrical system 8. The high-voltage battery 10 thus supplies the high-voltage electrical system 8 and operates the main drive 6. The high-voltage battery 10 provides a direct current between 400 V and 800 V, with the electrical currents flowing between the high-voltage battery 10 and the main drive 6 being able to reach several tens of A. Furthermore, the high-voltage electrical system 8 is connected to a charging port (not shown in detail), so that the high-voltage battery 10 can be charged via the charging port and the high-voltage electrical system 8.

[0084] A circuit breaker 12 is incorporated into the high-voltage on-board network 8, by means of which the high-voltage on-board network 8 is protected. The circuit breaker 12 makes it possible to prevent an electrical current flow between the high-voltage battery 10 and the main drive 6. The circuit breaker 12 triggers in the event of a fault, so that in the event of a fault, for example in the event of damage to the main drive 6, further damage or uncontrolled behavior of the main drive 6 and also endangerment of occupants or passers-by are avoided. Furthermore, the circuit breaker 12 is signal-connected to an on-board computer (not shown in detail), by means of which safe functions are carried out with the involvement of the circuit breaker 12 or requests to carry out safe functions are transmitted to the circuit breaker 12, which are subsequently at least partially carried out by means of the computer.Consequently, the circuit breaker 12 also serves to provide functional safety.

[0085] The circuit breaker 12 is also electrically connected to a low-voltage electrical system 14, which is powered by a battery 16. During operation, the battery 16 provides a direct voltage of 24 V, and the low-voltage electrical system 14 supplies power to auxiliary units (not shown in detail) that serve to operate the main drive 6 and / or provide comfort functions.

[0086] In Figure 2A simplified circuit diagram of the circuit breaker 12 is shown. The circuit breaker 12 has a main current path 18 that extends between two connections 20. The two connections 20 are screw or plug connections and are incorporated into a housing of the circuit breaker 12 (not shown in detail), which is made of a plastic. The circuit breaker 12 also has another main current path 22 that extends between two further connections 24 that are identical in construction to the connections 20. The main current path 18 and the further main current path 22 form part of the high-voltage vehicle electrical system 8, which thus has the main current path 18. For this purpose, the connections 20 and the further connections 24 are electrically contacted with corresponding cables or other lines of the high-voltage vehicle electrical system 8.

[0087] The additional main current path 22 is created simply by means of a busbar made of a metal, such as copper or brass. The additional main current path 22 is connected to ground via the additional terminals 24, and during normal operation of the motor vehicle 2, the direct current provided by the high-voltage battery 10 is present between the main current path 18 and the additional main current path 22. In other words, the main current path 18 and the additional main current path 22 are assigned to different poles of the high-voltage battery 10.

[0088] A mechanical switch 26 is incorporated into the main current path 18, by means of which the two terminals 20 are connected, and which is designed as a double breaker. For this purpose, the mechanical switch 26 has a fixed contact 28 and a further fixed contact 30, which are rigidly connected to one of the terminals 20 by means of a rigid busbar and spaced apart from each other. The two fixed contacts 28, 30 are made of a material different from the material of the associated busbars, which is particularly comparatively resistant to erosion.

[0089] The mechanical switch 26 further comprises a contact bridge 32 formed by a further busbar, which is mounted in a longitudinally displaceable, i.e., movable, manner by means of a guide (not shown in detail) of the housing of the circuit breaker 12. A moving contact 34 and another moving contact 36 are connected, namely welded, to the opposite ends of the contact bridge 32, wherein the material of the moving contacts 34, 36 corresponds to the material of the fixed contacts 28, 30.

[0090] By moving the contact bridge 32, it is possible to bring the moving contact 34 into direct mechanical contact with the fixed contact 28, and the further moving contact 36 into direct mechanical contact with the further fixed contact 30, so that they are each electrically connected. As a result, a low-resistance electrical connection exists between the two terminals 20, and the mechanical switch 26 is electrically conductive. In other words, the mechanical switch 26 is closed. Furthermore, it is possible to space the respective associated contacts 28, 30, 34, 36 from one another by adjusting the contact bridge 32. In this case, the mechanical switch 26 is electrically non-conductive and thus open.

[0091] The contact bridge 32 is driven by a drive 38, so that when the drive 38 is operated, the contact bridge 32 is adjusted and thus the mechanical switch 26 is closed or opened. Consequently, the drive 38 is operatively connected to the contact bridge 32, namely mechanically coupled to it. The drive 38 has a first drive unit 39, which is powered by a control unit 40. For this purpose, the control unit 40 is electrically connected to the drive 38, namely the first drive unit 39. To power the control unit 40, and consequently the first drive unit 39, the control unit 40 is electrically contacted by a control circuit 42, by means of which a direct voltage is provided. The control circuit 42 is electrically contacted directly by the low-voltage vehicle electrical system 14, so that the direct voltage of 24 V is also carried by means of the control circuit 42.In summary, the first drive unit 39 is thus energized by means of the control circuit 42.

[0092] The control unit 40 has an energy storage device 44 in the form of a capacitor, which is charged via the control circuit 42 and is electrically connected in parallel with a microcontroller of the control unit 40. Thus, fluctuations in the electrical voltage and / or current of the low-voltage electrical system 14 are absorbed by the energy storage device 44, thereby preventing damage to the microcontroller. The energy storage device 44 also makes it possible to actuate the drive 38 at least once in the event of a failure of the low-voltage electrical system 14, thus opening the switch 26.

[0093] In a variant illustrated in more detail, the control unit 40 also has a charge pump, which makes it possible to increase the electrical voltage applied to the capacitor 44 compared to the electrical voltage provided by the low-voltage electrical system 14, so that the amount of energy stored by the energy storage device 44 is increased. Thus, safe operation of the drive 38 is always possible, even if there is a complete failure of the low-voltage electrical system 14 or the drive 38 is slightly blocked.

[0094] The microcontroller adjusts the current supply to the first drive unit 39, which is signal-connected to a current sensor 46 of the main current path 18. The current sensor 46 is incorporated into the main current path 18 and designed as a shunt. Thus, the current sensor 46 enables measurement of the electrical current carried via the main current path 18. Furthermore, the circuit breaker 12 has a first voltage sensor 48, by means of which the electrical voltage present between one of the terminals 20 and one of the further terminals 24 can be measured. The electrical voltage present between the remaining terminal 20 and the remaining further terminal 24 can be measured by means of a second voltage sensor 50.

[0095] A third voltage sensor 52 measures the electrical voltage drop across the series circuit of the current sensor 46 and a resistance element 51 inserted between the current sensor 46 and the switch 26 in the main current path 18. A fourth voltage sensor 54 measures the electrical voltage drop across the series circuit of the current sensor 46, the resistance element 51, and the mechanical switch 26. All voltage sensors 48, 50, 52, and 54 are connected via signaling to the control unit 40, namely the microcontroller.

[0096] During operation, the microcontroller of the control unit 40 monitors the temporal change in the electrical voltages measured by the voltage sensors 48, 50, 52, 54 and the electrical current measured by the current sensor 46. If the temporal change in the measured current corresponds to an increase and exceeds a certain limit value, the control unit 40 controls the drive 38, namely the first drive unit 39, so that the switch 26 is opened. The limit value is selected such that it is only exceeded in the event of a fault, namely an electrical short circuit in the electric motor of the main drive 6. Actuation of the mechanical switch 26 interrupts the electrical current, thus preventing further damage to the electric motor or other components of the main drive 6.Likewise, the mechanical switch 26 is actuated by means of the control unit 40 when the electrical voltage detected by the voltage sensors 48, 50, 52, 54 is used to determine the fault, such as a malfunction of certain components of the motor vehicle 2.

[0097] A second drive unit 56 of the drive 38 is connected electrically parallel to the resistance element 51, which is electrically inserted between the further fixed contact 30 of the mechanical switch 26 and the current sensor 46 in the main current path 18. The second drive unit 56 is electrically connected to the main current path 18 via a rectifier 58. The rectifier 58, which has an internal electrical resistance, ensures that the electrical current carried by the second drive unit 56 flows only in a specific direction, regardless of the current flow direction of the main current path 18. Thus, the circuit breaker 12 is bidirectional, simplifying the construction of the second drive unit 56.A Zener diode 60 is connected between the rectifier 58 and the second drive unit 56, wherein the blocking direction is arranged such that the second drive unit 56 is only energized when a minimum voltage provided by the rectifier 58 is reached.

[0098] The resistance element 51 is a PTC thermistor and has a negligible ohmic resistance during normal operation. However, if the electrical current carried via the main current path 18 rises above a limit, the temperature of the main current path 18 and thus also of the resistance element 51 increases due to electrical losses, which is why the ohmic resistance of the resistance element 51 also increases. If the resistance is greater than the resistance of the branch connected in parallel with it, which includes the circuitry of the rectifier 58, the second drive train 56, and the Zener diode 60, the electrical current commutates from the resistance element 51 to the branch connected in parallel with it and thus also to the second drive unit 56, which is thus energized.As a result, a force is exerted by means of the second drive unit 56, which acts on the contact bridge 32, so that the moving contacts 34, 36 are spaced apart from the respectively associated fixed contacts 28, 30 and consequently the mechanical switch 26 is opened.

[0099] As a result, when a comparatively high electrical current is applied, the mechanical switch 26 is also opened by the second drive unit 56. It is possible to use both drive units 39, 56 to open the mechanical switch 26. In this case, a comparatively large force is applied to the contact bridge 32, which is why the switching time is shortened and the mechanical switch 26 is opened in a comparatively short period of time. Consequently, the current flow between the two terminals 20 is prevented within the comparatively short period of time. Furthermore, this provides redundancy, which increases safety.

[0100] However, it is also possible to operate each of the drive units 39, 56 separately from one another. In this case, the force acting on the contact bridge 32 is reduced, so that mechanical stress is also reduced. It is also possible to energize the first drive unit 39 via the control unit 40 in the event of faults, for example, where no overcurrent occurs or where the voltage drop across the resistance element 51 is insufficient for the electrical current to commutate to the second drive unit 56.

[0101] When the mechanical switch 26 is opened and a fault occurs, a comparatively high electrical voltage is present between the terminals 20 while the switch 26 is opening. As a result, an arc forms between the fixed contacts 28, 30 and the respective associated and moving moving contact 34, 36, through which a current continues to flow. However, the electrical voltage dropping across the mechanical switch 26 increases. As a result, the electrical current commutates from the electrical switch 26 to a fuse 56 connected in parallel thereto. Thus, the electrical current flows between the two terminals 20 via the fuse 62, which is why the arcs are extinguished.

[0102] Fuse 62 is dimensioned such that it trips in the event of a fault. The threshold at which fuse 62 trips lies between the value of the electrical current during normal operation and the value of the electrical current that results in a short circuit, whereby the exact value of the threshold in between can be freely selected without changing the functionality of circuit breaker 12. Thus, fault tolerances for fuse 62 can be selected to be comparatively large, which reduces manufacturing costs. After fuse 62 trips, no electrical current is carried through it either, and the two terminals 20 are galvanically isolated from each other.

[0103] In Figure 3The drive 38 is shown schematically in a sectional view along an axis 64. The drive 38 is designed as a "moving magnet actuator" and thus has two disc-coil or drum-like holders 66, which are arranged concentrically to the axis 64 and spaced apart along this axis. Between these, an annular short-circuit plate 68 is positioned concentrically to the axis 64, which is also made of a ferromagnetic material. By means of the holders 66 and the short-circuit plate 68, a hollow cylinder is thus formed, within which a further holder 70 made of a plastic is arranged and displaceably mounted along the axis 64 by means of a guide (not shown in detail). A rod 72 extending along the axis 64 is attached to the holder 70 and is attached to the contact bridge 32, either directly or via a mechanism (not shown in detail).A cylindrical permanent magnet 74 is embedded in the cylindrical further holder 70, which has two magnetic poles 76, each of which forms one of the ends of the permanent magnet 74 in a direction parallel to the axis 64.

[0104] The first drive unit 39 of the drive 38 comprises two electrical coils 78. Each of the electrical coils 78, which are structurally identical to one another, is wound on one of the holders 66, and these are electrically connected in parallel. The second drive unit 56 has two further electrical coils 80, one of which is wound on one of the electrical coils 78 and the other on the remaining electrical coil 78. The two further electrical coils 80 are also electrically connected in parallel. The number of turns of the further electrical coils 80 is fewer than the number of turns of the electrical coils 78.

[0105] When the two drive units 39, 56 are not energized, the permanent magnet 74 is drawn into a position substantially within the short-circuit plate 68 due to the magnetic interaction with the short-circuit plate 68 and the holders 66, whereby a force of approximately 30 N acts on the permanent magnet 70 and thus also on the further holder 70. This force also holds the short-circuit bridge 32 in the desired position, namely the position in which the mechanical switch 26 is closed.

[0106] In the event of a fault, the control unit 40 energizes the first drive unit 39, so that a magnetic field is created by means of the electrical coils 78, which interacts with the magnetic field of the permanent magnet 74. Current is also supplied to the second drive unit 56 and thus also to the further electrical coils 80. By means of these, the magnetic fields created by the electrical coils 78 are amplified. Due to the created magnetic fields, the permanent magnet 74 is pushed away from one of the holders 66 along the axis 64 and pulled towards the remaining holder 66. In this process, comparatively large forces act on the permanent magnet 74 and consequently, via the further holder 70 and the rod 72, also on the contact bridge 32, so that the mechanical switch 26 opens comparatively quickly.

[0107] If the fault does not occur and, for example, only the power supply to the main drive 6 is to be interrupted, for example for maintenance, the first drive unit 39 is energized by means of the control unit 40. Since there is no overcurrent, the electrical current does not commutate from the resistance element 51 to the second drive unit 56, whose other electrical coils 80 are therefore not energized. Consequently, a reduced force acts on the contact bridge 32, and the switch 26 opens comparatively slowly. As a result, the electrical and mechanical load on the circuit breaker 12 is reduced. Since the electrical voltage applied between the terminals 20 is limited in this case, the fuse 62 does not trip, and the circuit breaker 12 can be returned to the electrically conductive state, for example after maintenance has been completed.For this purpose, for example, the first drive unit 39 is energized in the opposite direction or the energization is stopped so that the permanent magnet 74 is again drawn to the short-circuit plate 68.

[0108] In Figure 4 An alternative embodiment of the circuit breaker 12 is shown schematically in a simplified form, wherein some components, such as the main current path 22 and the voltage sensors 48, 50, 52, 54, are not shown. These are also present, however, as in the previous embodiment, they can also be omitted. The fuse 62 is omitted in this embodiment, but is also present in a variant not shown in detail. The first drive unit 39 and the control unit 40 are not shown, but, like the illustrated mechanical switch 26, are not modified.

[0109] In the variant shown here, the rectifier 58 is electrically connected in parallel to the series circuit of the current sensor 46 and the resistance element 51. However, here too, the Figure 2 shown different arrangement of the current sensor 46 is possible.

[0110] The second drive unit 56 is unchanged, but the Zener diode 60 is replaced by a second switch 82, which is controlled by a second control unit 84. The second switch 82 is a semiconductor switch and is connected between the rectifier 58 and a second current sensor 86, which is electrically connected between the second switch 82 and the second drive unit 56.

[0111] The second current sensor 86 serves to measure the electrical current conducted to and carried by the second drive unit 56 and is signal-connected to the second control unit 84.

[0112] The second control unit 84 is energized by means of a second voltage supply 88, which is electrically contacted with the outputs of the rectifier 58 facing the second drive unit 56. Consequently, the second voltage supply 88 and thus also the second control unit 84 are only energized when the electrical voltage drop across the resistance element 51 is greater than that of the branch connected in parallel thereto. The second switch 82 is closed by the second control unit 84 as soon as it is energized, so that the second drive unit 56 is energized and consequently the mechanical switch 26 is opened. However, if the overcurrent is comparatively large and could lead to the destruction of the second drive unit 56, the second switch 82 is opened by means of the second control unit 84 and the energization of the second drive unit 56 is thus terminated.The excessive overcurrent is determined based on the electrical current measured by the second current sensor 56. Furthermore, the second switch 82 can be used to apply a pulse-width-modulated voltage to the second drive unit 56, thereby limiting the force exerted on the contact bridge 32 by the second drive unit 56.

[0113] The rectifier 58 has a total of four diodes 90 and is thus passively designed. Thus, no control unit or the like is required for the operation of the rectifier 58, thus increasing robustness. The resistance element 51 is formed by two additional switches 92, each of which is a semiconductor switch connected in reverse series. The additional switches 92 are controlled by an additional control unit 94, which is powered by the control circuit 42.

[0114] The additional control unit 94 is signal-connected to the current sensor 46. When the overcurrent is measured by the current sensor 46, this is evaluated by the additional control unit 94, and the additional switches 92 are controlled in such a way that they open, i.e., electrically block. Due to the anti-serial connection of the two additional switches 92, the current flow can be interrupted in both directions via the main current path 18.

[0115] After the additional switches 92 are opened, the resistance element 51 essentially suddenly exhibits a comparatively high electrical resistance, and the electrical current commutates to the second drive unit 56. To prevent an overvoltage at the rectifier 58 and the resistance element 51, an overvoltage protection device 96, which in this variant is a varistor, is connected in parallel. In a variant not shown in detail, the overvoltage protection device 96 is implemented using Zener diodes, TVS diodes, an RCD circuit, a controllable resistive load, or a combination thereof.

[0116] The additional control unit 94, as shown, is signal-connected to the second control unit 84, and the additional control unit 94 controls the second control unit 84 such that the second switch 82 is closed when the additional switches 92 are opened. In a variant not shown in detail, the second control unit 84 is not present, and its functions are taken over by the additional control unit 94, by means of which the second switch 82 is controlled and the second current sensor 86 is read. In a further variant, the signal-connection between the additional control unit 94 and the second control unit 84 is not present, and these are separate and independent of one another.

[0117] In the variant shown here, a series circuit comprising a second resistance element 98, an additional current sensor 100, and an additional fuse 102 is connected in parallel to the series circuit comprising the current sensor 46 and the resistance element 51. However, a design of the circuit breaker 12 without these series circuits and consequently without the second resistance element 98 is also possible.

[0118] The second resistance element 98 is formed by two additional switches 104, each configured as a semiconductor switch. The two semiconductor switches 104 are connected anti-serially to one another, so that an electrical current flow in both directions can be interrupted by means of them. The two additional switches 104 are operated by a second additional control unit 106, which is powered by a second additional voltage supply 108. The second additional voltage supply 108 is operated based on the electrical voltage drop across the second resistance element 98. Connected in parallel to the second resistance element 98 is a second overvoltage protection device 110, which in the illustrated variant is also a varistor. However, all possible variants for the overvoltage protection device 96 can also be used here.In an embodiment not shown in detail, the functioning of the second overvoltage protection 110, namely the limitation of the electrical voltage applied to the second resistance element 98, is also carried out by means of the overvoltage protection 96.

[0119] In the illustrated variant of the circuit breaker 12, the additional switches 92 have a comparatively low internal resistance, so that during normal operation they conduct the electrical current carried via the main current path 18. The electrical voltage drop across the second resistance element 98 is comparatively low, which is why the second additional voltage supply 108 and therefore also not the additional control unit 106 is operated. As a result, the second additional switches 104 are open. When a fault occurs, the additional switches 92 are initially actuated by the additional control unit 94. The resulting increased electrical voltage drop across the second resistance element 98 leads to the operation of the second additional voltage supply 108 and therefore also to the energization of the additional control unit 106, by means of which the second additional switches 104 are closed.Thus, the electrical current commutates to the second resistance element 98, i.e., the second additional switch 104. As a result, the maximum electrical voltage applied to the resistance element 51 is limited, and only a comparatively low electrical voltage is switched by means of the additional switch 92, so that semiconductors can be used comparatively inexpensively for the additional switch 92.

[0120] Only after the additional switches 92 have blocked the current are the second additional switches 104 opened, whose switching capacity is increased compared to that of the additional switches 92. In other words, switching an increased electrical voltage is also possible using the second additional switches 104 without damaging them. The electrical current then flows through the second drive unit 56 and, if applicable, through the overvoltage protection devices 96, 110, and the mechanical switch 26 is subsequently opened.

[0121] As long as the second additional switches 104 are energized, the electrical current they carry is measured by the additional current sensor 100. If the electrical current exceeds a corresponding limit value that could lead to the destruction of the second additional switches 104, they are opened by the additional control unit 106, thus interrupting the current flow. The additional fuse 102 serves as redundancy for this purpose, particularly in the event of a malfunction of the additional control unit 106.

[0122] In Figure 5A further variant of the circuit breaker 12 is shown, wherein, compared to the previous embodiment, the series connection with the second resistance element 98, the additional current sensor 100, and the additional fuse 102 is replaced by a choke 112. By means of this, the temporal change of the electrical current conducted via the second drive unit 56, the overvoltage protection 96, and / or the resistance element 51 is limited when the mechanical switch 26 is actuated, i.e., the current flow via the main current path 18 is established or terminated. This reduces the load on these components. This makes it possible to use comparatively cost-effective components. The general functioning of the second drive unit 56, the rectifier 58, the resistance element 51, the additional control unit 94, and the second control unit 84, and their corresponding interconnections, however, remain unchanged.

[0123] In this variant, the mechanical switch 26 is bridged by a series circuit comprising a switch group 114, a third current sensor 116, and a third fuse 118. The switch group 114 comprises two semiconductor switches 120 connected in series with one another. Consequently, the two semiconductor switches 120 are connected in parallel with the mechanical switch 26. The two semiconductor switches 120 are operated by a further control unit 122 and are set to either an electrically conductive or electrically non-conductive state by this control unit. The further control unit 122 is energized by a further voltage supply 124, which is fed either by an electrical voltage drop across the mechanical switch 26 or by the control circuit 42.

[0124] Connected in parallel to switch group 114 is an additional surge protector 126, which in the illustrated variant is a varistor. In a variant not shown in detail, the additional surge protector 126 is implemented using Zener diodes, TVS diodes, an RCD circuit, a controllable resistive load, or a combination thereof. The additional surge protector 126 prevents electrical overvoltage at switch group 114, as well as the additional control unit 122 and the additional power supply 124, which could otherwise lead to their destruction.

[0125] In summary, the structure of the additional surge protector 126, the switch group 114, the additional control unit 122, the additional power supply 124, the third current sensor 116 and the third fuse 118 corresponds to the structure of the second surge protector 110, the second resistance element 98, the second additional control unit 106, the second additional power supply 108, the additional current sensor 102 and the additional fuse 102.

[0126] In this embodiment of the circuit breaker 12, the semiconductor switches 120 are not electrically conductive as long as the mechanical switch 26 is closed. When the switch 26 is opened, the electrical voltage applied across the switch group 114 increases, so that the additional voltage supply 124 is operated and therefore the additional control unit 122 is energized. The additional control unit 122 controls the switch group 114, namely the individual semiconductor switches 120, so that they become current-conducting. As a result, the electrical current commutates and is conducted by the switch group 114. Therefore, the arcs formed between the fixed contacts 28, 30 and the respective moving contacts 34, 36 are extinguished. The semiconductor switches 120 are then electrically controlled such that they are electrically blocked, thus ending the flow of electrical current between the two terminals 20.

[0127] The additional overvoltage protection 126 ensures that the semiconductor switches 120 are not overloaded until then. If the additional current sensor 116, which is signal-connected to the additional control unit 122, detects that a comparatively large electrical current is being conducted through the switch group 114, which could lead to damage to the semiconductor switches 120, the semiconductor switches 120 are also opened, thus preventing damage to the switch group 114. The additional fuse 118 ensures that the current flow through the switch group 114 is interrupted even in the event of a malfunction of the additional control unit 122 or a comparatively high electrical current.

[0128] In this variant of the circuit breaker 12, there are several different sequences for controlling the individual components in order to open the circuit breaker 12. For example, it is possible for the switch group 114 to be energized first and then the mechanical switch 26 to open. Following this, the switch group 114 is transferred to the electrically non-conductive state. In this way, arc-reduced switching occurs by means of the circuit breaker 12. However, it is also possible to first actuate the mechanical switch 26 so that the further control unit 122 is energized using the electrical voltage generated via the mechanical switch 26. Following this, the switch group 114 is transferred to the electrically conductive state so that the arcs are extinguished. Subsequently, the switch group 114 is also transferred to the electrically non-conductive state.In another control method, switch group 114 is first placed in the electrically conductive state, and then resistance element 51 is placed in the electrically non-conductive state. Consequently, mechanical switch 26 is opened. Subsequently, switch group 114 is placed in the electrically non-conductive state, with the current increase being limited during or until this time by means of choke 112.

[0129] In a further development not shown in detail, the circuit breaker 12 is in accordance with Figure 5 However, the bridging of the mechanical switch 26 is omitted. In other words, the switch group 114, the additional control unit 122, the additional power supply 124, the additional overvoltage protection 126, as well as the third current sensor 116 and the third fuse 118 are not present.

[0130] In Figure 6A further embodiment of the circuit breaker 12 is shown. In comparison to the previous embodiment, the series circuit of the switch group 114, the third current sensor 116 and the third fuse 118 bridges not only the mechanical switch 26, but also the series circuit of the mechanical switch 26, the resistance element 51 and the current sensor 46. In addition, the choke 112 is omitted, although it can also be present here. In comparison to the Figure 4In the variant shown, the additional fuse 102 is connected on the opposite side of the mechanical switch 28 against the main current path 18, so that the series circuit of the second resistance element 98, the additional current sensor 100, and the additional fuse 102 bridges the series circuit of the current sensor 46, the resistance element 51, and the mechanical switch 26. In this variant, it is also possible for the choke 112 to be present.

[0131] In the event of an overcurrent, the additional control unit 94 controls the resistance element 51 so that it is no longer conducting current. As a result, the electrical current commutates to the second drive unit 56, which has an electrical resistance. Therefore, the electrical voltage drop across the second resistance element 98 or the switch group 114 increases, causing the second additional voltage supply 108 or the further voltage supply 124 to operate. The second resistance element 98 or the switch group 114 is now electrically conductive by means of the second additional control unit 106 or the further control unit 122.

[0132] Due to the continuous current supply to the second drive unit 56 during this time, the mechanical switch 26 is opened. As a result, the electrical current is subsequently conducted between the terminals 20 solely by means of the second resistance element 98 or the switch group 114. The current rise via this branch is limited by means of any choke 112 present, thus preventing overloading. Subsequently, the second resistance element 98 or the switch group 114 is switched to the electrically non-conductive state by means of the second additional control unit 106 or the further control unit 122, so that the electrical current flow between the two terminals 20 is terminated. In this variant, no arc is formed via the mechanical switch 26.

[0133] In Figure 71 shows a perspective view of an arcing chamber 128 of the mechanical switch 26. The arcing chamber 128 serves to extinguish an arc that occurs during a switching operation of the mechanical switch 26, unless the other existing components are used for this purpose. The arcing chamber 128 has a plurality of arcing strips 132 stacked one above the other in a stacking direction 130. The arcing strips 132 are made of an aluminum oxide ceramic, are flat, and are arranged perpendicular to the stacking direction 130. The thickness of the arcing strips 132, i.e. their extent in the stacking direction 130, is between 1 mm and 2 mm. The arcing strips 132 lie directly against one another, forming a stack 134. The stack 134 has a plurality of layers 136 arranged one above the other in the stacking direction 130, which are thus arranged perpendicular to the stacking direction 130.

[0134] Two of the extinguishing strips 132 are assigned to each of the layers 136. The two extinguishing strips 132 of each layer 136 are different from one another, with one of the extinguishing strips 132 being wedge-shaped and the remaining one being trapezoidal. In other words, the extinguishing strips 132 assigned to each of the layers 136 are different, but each layer 136 is assigned the same extinguishing strips 132, i.e., the same type. In other words, the extinguishing chamber 128 has two different types of extinguishing strips 132, namely wedge-shaped and trapezoidal, and these are evenly distributed among the layers 136.

[0135] The two eraser strips 132 of each layer 136 are spaced apart from one another perpendicular to the stacking direction 130, so that a slot 138 is formed between them. Four of the layers 136 are combined to form a group 140, with the eraser strips 132 of each group 140 being arranged flush with one another. The eraser strips 132 of the adjacent group 140, however, are arranged mirror-inverted, so that the stack 134 has a plurality of chambers 142 lying one above the other in the stacking direction 130 and separated from one another, each formed by the mutually aligned slots 138. Due to the wedge or trapezoidal shape, a notch 144 is formed in each of the layers 136, which merges into the respective chambers 142. There are a total of four such groups 140.

[0136] The stack 134 is gripped on both sides by a holder 146, thus stabilizing it. The holders 146 are mirror images of each other, are made of plastic, and each have a foot 148. The two holders 146 are fastened to each other at the respective foot 148, so that the stack 134 is held force-fittingly between the two holders 146 both in the stacking direction 130 and perpendicular to it. On the side opposite the stack 134, each of the holders 146 has a rectangular pot- or pan-shaped receptacle 150, within which a permanent magnet 152 is located in the assembled state, each of which forms a driving element.

[0137] The arcing chamber 128 is oriented with respect to the fixed contacts 28, 30 and the moving contacts 34, 36 such that an arc created when the mechanical switch 26 is actuated, i.e., when the drive 38 is actuated, strikes the stack 134 in the region of the notches 144. Due to the interaction between the magnetic field of the permanent magnets 152 and the magnetic field created by the arc, the arc is driven further into the stack 134, namely into the individual chambers 142. Thus, U-shaped sections of the arc are formed in the respective chambers 142. The sections are connected to one another, with the connecting sections encompassing the stack 134 on the side of the notches 144. Consequently, the arc has a comparatively long length. Due to the notches 144, the arc cannot bypass the arcing chamber 128.As the length of the arc increases, the electrical voltage required to maintain it increases.

[0138] Furthermore, heat is introduced from the plasma forming the arc into the individual quenching strips 132, cooling the arc. Due to the ceramic used, the heat is dissipated comparatively effectively, thus cooling the arc. Due to the cooling, the electrical voltage required to maintain the arc also increases. Since the individual quenching strips 132 are separate from one another, even if the individual quenching strips 132 are heated unevenly, no excessive mechanical stress, which could lead to destruction, develops in the stack 134.

[0139] If the throttle 112 is present, as for example in the Figure 5illustrated embodiment and the modification described there, not shown, or in the non-illustrated development of the further embodiment of the Figure 6 , in a further development, this is also used to drive the arc into the chambers 142. In this case, the choke 112 is positioned accordingly and thus acts as a so-called blowout field coil. Thus, the permanent magnets 152 can be omitted, or they can be present additionally for support. The choke 112 is only energized when the mechanical switch 26 is actuated. Thus, the magnetic field for driving the arc into the chambers 142 is only generated when the arc is actually present or at least could be formed. List of reference symbols

[0140] 2 Motor vehicle 4 Wheel 6 Main drive 8 High-voltage electrical system 10 High-voltage battery 12 Circuit breaker 14 Low-voltage electrical system 16 Battery 18 Main current path 20 Connection 22 Further main current path 24 Further connection 26 Mechanical switch 28 Fixed contact 30 Further fixed contact 32 Contact bridge 34 Moving contact 36 Further moving contact 38 Drive 39 First drive unit 40 Control unit 42 Control circuit 44 Energy storage device 46 Current sensor 48 First voltage sensor 50 Second voltage sensor 51 Resistance element 52 Third voltage sensor 54 Fourth voltage sensor 56 Second drive unit 58 Rectifier 60 Zener diode 62 Fuse 64 Axle 66 Holder 68 Shorting plate 70 Additional holder 72 Rod 74 Permanent magnet 76 Magnetic pole 78 Electric coil 80 Additional electric coil 82 Second switch 84 Second control unit 86 Second current sensor 88 Second power supply 90 Diode 92 Additional switch 94 Additional control unit 96 Overvoltage protection 98 Second resistance element 100 Additional current sensor 102 Additional fuse 104 Second additional switch 106 Second additional control unit 108 Second additional power supply 110 Second overvoltage protection 112 Choke 114 Switch group 116 Third current sensor 118 Third fuse 120 Semiconductor switch 122 Additional control unit 124 Additional power supply 126additional surge protection 128extinguishing chamber 130stacking direction 132extinguishing strip 134stack 136layer 138slot 140group 142chamber 144notch 146holder 148foot 150receptacle 152permanent magnet

Claims

1. Circuit breaker (12) having a mechanical switch (26), which is incorporated into a main current path (18) that extends between two connections (20), and which has a fixed contact (28) and a moving contact (34) that is connected to a contact bridge (32) mounted so as to be able to move relative thereto, and having a drive (38) that is operatively connected to the contact bridge (32), with the result that it is possible to move the contact bridge (32) from one position to another position by actuating the drive (38), wherein the drive (38) has a first drive unit (39) and a second drive unit (56) that are able to be operated or are operated separately from one another such that the contact bridge (32) is moved, wherein the first drive unit (39) is energized by means of a control circuit (42), and wherein the second drive unit (56) is connected in parallel with a resistor element (51) incorporated into the main current path (18), characterized in that the resistor element (51) comprises an additional switch (92) that is actuated by means of an additional control unit (94).

2. Circuit breaker (12) according to Claim 1, characterized in that the second drive unit (56) is connected to the main current path (18) via a rectifier (58).

3. Circuit breaker (12) according to Claim 1 or 2, characterized in that a Zener diode (60) and / or a second switch (82) are / is connected between the second drive unit (56) and the main current path (18).

4. Circuit breaker (12) according to one of Claims 1 to 3, characterized by a control unit (40), which is fed from the control circuit (42) and by means of which the first drive unit (39) is energized.

5. Circuit breaker (12) according to one of Claims 1 to 4, characterized in that a fuse (62) is connected in parallel with the mechanical switch (26).

6. Circuit breaker (12) according to one of Claims 1 to 5, characterized in that a semiconductor switch (120) is connected in parallel with the mechanical switch (26) or the series connection comprising the mechanical switch (26) and the resistor element (51).

7. Circuit breaker (12) according to one of Claims 1 to 6, characterized in that the mechanical switch (26) has an extinguishing chamber (128) that comprises a plurality of flat extinguishing strips (132) that are arranged in parallel with one another, are stacked one above another in a stacking direction (130) and are made of a ceramic.

8. Motor vehicle (2), having a high-voltage on-board electrical system (8), and having a low-voltage on-board electrical system (14), and having a circuit breaker (12) according to one of Claims 1 to 7, wherein the control circuit (42) is electrically connected to the low-voltage on-board electrical system (14), and wherein the high-voltage on-board electrical system (8) comprises the main current path (18).