Residual current protection element and method for detecting a residual current

Abstract

The invention relates to a residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) for detecting a fault current in electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), the residual current protection element comprising at least two parallel electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), a carrier substrate (102) which supports the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) carries, and two magnetic sensors (105a, 105b) connected in such a way that they generate a differential measurement signal.

Description

The present invention relates to a residual current protection element for detecting a residual current in electrical conductors, to a residual current circuit breaker and to a method for determining a residual current.BACKGROUND OF THE INVENTIONA residual current circuit breaker (FI circuit breaker) is a safety device which serves to prevent residual currents in electrical circuits or which interrupt the electrical circuit in the event of residual currents occurring. Sockets, in particular also those in vehicles, must be protected by a residual current circuit breaker according to ISO specifications.Disclosure of the InventionAccording to the invention, a residual current protection element for detecting a residual current in electrical conductors, a residual current circuit breaker and a method for determining a residual current having the features of the independent patent claims are proposed. Advantageous embodiments are the subject matter of the dependent claims and of the following description.The invention relates to a residual current protection element for detecting a residual current in electrical conductors. The residual current protection element can be used in particular in a residual current protection switch (also referred to as a FI circuit breaker or FI switch) which is configured to interrupt the electrical conductors when a residual current is detected.The residual current protection element according to the invention has two parallel-running electrical conductors, a carrier substrate which carries the two electrical conductors, and two magnetic sensors.The carrier substrate can be, for example, a printed circuit board (PCB) or a printed circuit board. As a result, a very cost-effective element can be provided.Hall effect sensors, reed switches, GMR sensors, AMR sensors or magnetoinductive sensors can be used as magnetic sensors, for example. These are widely used and tested magnetic sensors with high sensitivity.The two electrical conductors can be designed in particular as busbars, which can be connected to the carrier substrate, for example, by means of a soldered connection. Furthermore, the electrical conductors can be produced on the carrier substrate by etching a continuous conductive layer applied to the carrier substrate, wherein the structure of the two electrical conductors can be determined by a resist mask defined, for example, by means of photolithography. As a result, a very cost-effective element can be provided.A current flow through the two electrical conductors generates a magnetic field which passes through the two magnetic sensors. By means of the two magnetic sensors, it is possible in particular to carry out a differential magnetic field measurement, wherein the two magnetic sensors are located at spatially different positions. The difference between the measured magnetic field values at the two magnetic sensors is determined as the measurement signal, as a result of which changes in the magnetic field passing through the magnetic sensors can be determined. The differential measuring arrangement is particularly accurate because, for example, magnetic interference fields and / or temperature fluctuations can be compensated, which allows an increased sensitivity of the differential measuring method. Differential magnetic field measurement is understood to mean a measurement in which a difference of the amounts of the two magnetic fields is formed as a result. In addition to an actual difference, this can also be carried out, for example, by summing a positive and a negative value.Furthermore, in embodiments of the invention, it is also possible to determine absolute magnetic field values by means of the magnetic sensors, which allows, for example, a conclusion to be drawn about the current intensity.The functionality of the fault current protection element according to the invention is explained in the following by way of example. In this case, a current flow through the two electrical conductors generates a magnetic field which can be determined by means of the two magnetic sensors. The two magnetic sensors can be arranged, for example, such that, in the case of a reverse current flow of the same amplitude through the two electrical conductors, the magnetic fields generated by the first and the second electrical conductor at the position of the magnetic sensors are approximately compensated in total. If a higher current now flows through one of the two conductors, the magnetic fields generated by the respective current flow through the two conductors at the position of the magnetic sensors no longer completely compensate one another. This leads to a change in the magnetic field signal determined by means of the magnetic sensors, which can serve as a basis for carrying out certain measures, for example a break in the electrical connection of the two electrical conductors. The change in the magnetic field signal can be determined in particular by means of a differential magnetic field measurement, but also on the basis of absolute magnetic field values.The two electrical conductors can be connected in particular, so that one of the two electrical conductors is designed as a neutral conductor and the other electrical conductor is designed to conduct phases. If the sum of the currents in the phase-conducting electrical conductor and the neutral conductor is not zero, this would indicate a parasitic current flow, a so-called fault current, which can flow off, for example, by a defective electrical load or a person. As explained above, this residual current leads to the magnetic fields generated by the two electrical conductors at the position of the magnetic sensors no longer being completely compensated, resulting in a change in the magnetic field signal determined by means of the magnetic sensors, on the basis of which, for example, the circuit can be interrupted in order to prevent a risk due to parasitic current flow.It is particularly advantageous here to implement the residual current protection element on a carrier substrate, for example a printed circuit board, as a result of which the residual current protection element can be easily connected to further electronic components and integrated into an electronic vehicle system. This allows simple integration of the residual current protection element into an electronic circuit, which allows, for example, inter alia, the evaluation of the magnetic field signal determined by means of the magnetic sensors. Furthermore, the embodiment on a printed circuit board allows a cost-effective and space-saving possibility for the realization of the residual current protection element, since in particular only a small number of components is required for the construction of the residual current protection element. A further advantage of the fault current protection element according to the invention is that no magnetic flux concentrator is required, which is associated in particular with a smaller space requirement, a smaller weight and a smaller cost. Since the fault current detection by means of the fault current protection element according to the invention is based on the determination of a differential magnetic field, it is also possible to determine a differential current both for direct current and for alternating current, which results in a broad range of applications.Preferred fields of application of the fault current protection element according to the invention are, for example, an implementation in high-voltage control units of vehicles which have one or more sockets, or in on-board charging devices of vehicles, for example those which, on the one hand, transform the high voltage by means of a DC / DC converter into a lower voltage, typically 12 V, required for operating an on-board power supply system and, on the other hand, can also be used for charging a high-voltage battery.The invention also relates to a residual current circuit breaker having a residual current protection element according to the invention and a interrupter which is configured to interrupt the at least two electrical conductors in response to a detected residual current.A fault current can arise, for example, as a result of damage to insulations of electrical conductors, inadequate grounding or defective electrical components and can pose a risk to persons, in particular if the fault current flows through a person. By interrupting the electrical conductors, the current flow, in particular the fault current flow, is interrupted and the corresponding risk is prevented at an early stage or the risk of a potentially dangerous situation occurring is reduced.In one embodiment, the at least two electrical conductors can each have a cross section with two parallel longer sides. The conductors are in particular flat, i.e. the distance between the two parallel longer sides is significantly greater than the side length of these sides (in other words the conductor is very much wider than high (when viewed "horizontally"), e.g. more than twice as wide or more than ten times as wide. The cross section can be rectangular, i.e. the conductor has, in addition to the two parallel longer sides, also two parallel shorter sides which are perpendicular to the longer sides. The shorter sides can, however, also be rounded, or the corners can be rounded. Electrical conductors having such a cross section can be realized easily on a printed circuit board in the form of conductor tracks. In addition, compared to an electric conductor having a round cross section, an electric conductor having a flat cross section, through the larger surface area thereof compared to the cross-sectional area, enables better heat dissipation.In a further embodiment, one or the two magnetic sensors may be located on a surface of the carrier substrate. Here, the two magnetic sensors may be located on the same surface (e.g., a top or bottom), or on different surfaces (e.g., one on the top and the other on the bottom). This allows simple maintenance and / or repair and simple replacement of the magnetic sensors, since these are easily accessible. By attaching the magnetic sensors to the surface of the carrier substrate, good heat dissipation is also possible, which contributes in particular to improved measurement accuracy due to higher thermal stability. Further, in this embodiment, it is possible to easily connect other electronic components to the magnetic sensors because they are easily accessible.In a further embodiment, one or the two magnetic sensors can be integrated or embedded or embedded in the carrier substrate. This has the advantage that the magnetic sensors are protected from external influences, for example air humidity or dust, which can improve in particular the reliability and longevity of the magnetic sensors.If one of the two electrical conductors is located on the upper side of the carrier substrate and the other electrical conductor is located on the lower side, so that these are arranged lying one above the other parallel to a main extension plane of the carrier substrate or if this is arranged horizontally, it is possible on the other hand to place the two magnetic sensors in such a way that they ideally lie in the plane in which the magnetic fields generated by the two electrical conductors cancel out. In this case, it is assumed that currents of the same current intensity flow through the two electrical conductors in opposite directions. This arrangement allows for example an increased accuracy in the determination of differential currents.In particular, large magnetic field differences between the positions of the two sensors, for example due to a non-linear sensitivity of the magnetic sensors, can lead to an inaccurate determination of the magnetic field difference. At the same time, it would be possible in this case for thermal effects at the two magnetic sensors to be of different significance, which would additionally have a negative influence on the accuracy, in particular the differential magnetic field measurement. Due to this, in particular the symmetrical arrangement of the magnetic sensors relative to the electrical conductors according to the described embodiment is advantageous.In a further embodiment, one or the two magnetic sensors can be attached or arranged in a depression of the carrier substrate. This allows improved positioning of the two magnetic sensors, analogously to the above exemplary embodiment, in which the two magnetic sensors are integrated into the carrier substrate. A further advantage of the embodiment in which one or both magnetic sensors are arranged in a depression is that the production process can be realized more easily, in particular in comparison with a complete integration of the magnetic sensors into the carrier substrate, since only one additional depression is required, which can be produced, for example, by milling. Since the two magnetic sensors are located on the surface of the carrier substrate in this case, their electrical contacting and the production of electrical connections, in particular to other electronic components, can also be implemented in a simple manner.In a further embodiment, the two electrical conductors are formed on different sides of the carrier substrate. As a result, the fault current protection element can be realized in a particularly space-saving manner, since the two conductors can be arranged parallel to the main extension plane of the carrier substrate or, if the latter is arranged horizontally, in particular lying one above the other. In this compact configuration, the magnetic fields generated by a current flow through the two electrical conductors can have a small spatial extent, in particular in comparison to arrangements in which the two conductors are arranged next to one another and are spaced further apart from one another.Furthermore, the magnetic sensors in this embodiment can be arranged such that, as described above, they are integrated into the carrier substrate or are located in a depression of the carrier substrate. This allows an improved positioning of the magnetic sensors relative to the magnetic fields generated by a current flow through the electrical conductors, so that, in the case of a current flow of opposite direction but of the same amplitude through the two conductors, the magnetic fields compensate for one another at the position of the magnetic sensors, whereby, for example, an accurate differential magnetic field measurement is possible.In a further embodiment, the two electrical conductors are formed on the same side of the carrier substrate. This simplifies, for example, the production process of the residual current protection element, since the two electrical conductors can be produced in particular in one process step. This allows a cost-effective implementation of the conductors which can be produced, for example, by etching specific regions of a continuous conductive layer on the carrier substrate, wherein the specific regions can be predefined, for example, by a photolithographically defined resist mask.It is possible in particular for the magnetic sensors and the electrical conductors to be arranged on opposite sides of the carrier substrate. This can prevent, for example, the electrical conductors from being damaged when the magnetic sensors are arranged.In a further embodiment, at least one of the at least two electrical conductors is embedded in the carrier substrate. It can thereby be protected from negative influences or damage. Wiring or contacting of the sensors can also be produced more easily.In a further embodiment, the cross section or the cross-sectional area (perpendicular to a current direction) of the two electrical conductors can be reduced at at least one point in each case, wherein the reduction of the cross-sectional area is in each case designed in the form of at least one cutout. As a result, for example, the properties of the magnetic field generated by a current flow through the electrical conductors can be adapted. By reducing the cross-sectional area, the current is concentrated at this location, which leads to a higher current density and thus to a more concentrated magnetic field. Furthermore, it is thereby possible to use magnetic sensors which are installed in a housing. The cross section of the electrical conductors can be adapted accordingly such that the magnetic sensors, in particular including their housings, can be advantageously arranged. The cross section of the electrical conductors can be adapted in particular to the width of the housings of the magnetic sensors.In this case, two recesses can be formed on the edge of the electrical conductor, such that the recesses are arranged on different sides, but at the same position with respect to the longitudinal axis of the conductor. In a plan view of the main extension plane of the carrier substrate, this results in particular in a tapering of the electrical conductor formed symmetrically to the longitudinal axis or longitudinal plane of the electrical conductor.Furthermore, two recesses can be formed on the edge of the electrical conductor, so that the recesses are arranged on different sides and at different positions with respect to the longitudinal axis of the electrical conductor. In plan view of the main extension plane of the carrier substrate, this results in an S-shaped form of the electrical conductor.Furthermore, in the plan view of the main extension plane of the carrier substrate, a cutout can be formed in the interior of the electrical conductor, in particular symmetrically with respect to the longitudinal axis or the longitudinal plane of the electrical conductor. In this case, the current flow splits into two branches that lead around the recess.It is thus possible, for example, to adapt the magnetic field strength at specific spatial positions by adapting the cross section of the electrical conductors, with the result that the magnetic field strength is increased in particular at specific spatial positions. The magnetic sensors can be arranged at positions at which the magnetic field strength is increased, whereby the measured magnetic field signal increases, so that in particular the signal-to-noise ratio is improved.In a further embodiment, the magnetic sensors may be arranged at positions at or next to which the cross-sectional area of the electrical conductors is reduced, such that the magnetic sensors are located in particular in the recess of the conductors. On the one hand, this makes it possible for the magnetic sensors to be arranged at positions at which the magnetic fields generated by a current flow through the electrical conductors are particularly high, which can improve the accuracy of the magnetic field measurement in particular. On the other hand, the magnetic sensors can be located within a base area enclosed by the electrical conductors, which in particular allows space-saving accommodation of the magnetic sensors. In particular, the magnetic sensors are designed or configured to detect a vertical magnetic field which runs perpendicular to the main plane of extension of the carrier substrate.In a further embodiment, the two electrical conductors can be arranged on different sides of the carrier substrate and the recesses of the two conductors, which result from a reduction in the cross-sectional area, are likewise arranged lying one above the other. The magnetic sensors can be arranged either in different recesses or in the same recess.In each case two recesses can be formed such that, according to one of the preceding embodiments, they are formed as a taper of the two conductors. The two magnetic sensors can be arranged in each case in one of the two recesses, so that they are formed in particular symmetrically with respect to the longitudinal axis or longitudinal plane of the electrical conductors. Furthermore, the two magnetic sensors can be arranged in a central recess, according to one of the preceding embodiments, such that they are situated in particular symmetrically with respect to the longitudinal axis or longitudinal plane of the electrical conductors. Furthermore, the two conductors can also each be S-shaped, corresponding to one of the embodiments described above. The two magnetic sensors can be located in one of the two recesses.The described embodiments allow a space-efficient accommodation of the two magnetic sensors and, due to the symmetrical arrangement of the magnetic sensors, in particular with respect to a current flow through the two electrical conductors, an advantageous implementation of a differential magnetic field measurement.In a further embodiment, the two conductors can be arranged next to one another in a plan view of the carrier substrate. As explained above, this arrangement allows simple production of the residual current protection element, since the two conductors can be located on the same side of the carrier substrate. The two magnetic sensors can be arranged on or overlapping with the electrical conductors in a plan view of the main extension plane of the carrier substrate. This represents a simple possibility for the implementation of the fault current protection element, wherein the two electrical conductors can be produced simply and economically, for example as busbars. In particular, the magnetic sensors are designed or configured to detect a transverse magnetic field which runs perpendicular to a central axis of the electrical conductors and parallel to the main extension plane of the carrier substrate.In a further embodiment, the residual current protection element can have at least one magnetic flux concentrator which encloses at least one of the conductors, preferably all of them. The at least one magnetic flux concentrator has at least one interruption in each case, so that a total of at least two intermediate spaces are produced. The two magnetic sensors are expediently each arranged in one of the at least two intermediate spaces.By using a magnetic flux concentrator, the strength of the magnetic field at the position of the magnetic sensors can be increased, in particular by reducing scattering losses, whereby smaller changes in the strength of the magnetic field can be detected by the magnetic sensors, for example. At the same time, a stronger magnetic field leads to a larger magnetic field signal detected by the magnetic sensors, so that in particular the signal-to-noise ratio is improved.Materials with a high magnetic permeability are particularly suitable for the realization of a magnetic flux concentrator, which allows effective conduction of the magnetic field. At the same time, the material used should have a low residual resistance and a low hysteresis. For example, magnetically soft materials such as iron or nickel, alloys such as permalloy, or ferrites are suitable for this purpose.In one embodiment, the residual current protection element has exactly two or exactly four electrical conductors. A two-phase or a three-phase alternating current can thus be protected. Of four electrical conductors, in particular three electrical conductors can be designed to conduct phases, and one electrical conductor can be designed as a neutral conductor.Three-phase terminals in connection with a neutral conductor are conventionally used, for example, for the operation of devices that require high electrical powers or three-phase current. These include, for example, electric motors, in particular those of electrically operated vehicles, air conditioners or industrial installations, such as conveyor belts or pumps.If the residual current protection element has exactly four electrical conductors, these are expediently always assigned in pairs to a magnetic sensor, wherein the four electrical conductors can be designed, for example, as four layers lying one above the other, or as two pairs lying next to one another of in each case two layers lying one above the other.A method according to the invention for determining a fault current uses a fault current protection element according to the invention. The method comprises the determination of a magnetic field value by means of the two magnetic sensors, respectively, and the determination of a residual current as the sum of the currents flowing through the at least two electrical conductors from the two determined magnetic field values. If the sum of the currents is zero, the difference of the magnetic fields is zero.Further advantages and embodiments of the invention will become apparent from the description and the accompanying drawing.The invention is schematically illustrated in the drawing on the basis of an exemplary embodiment and is described below with reference to the drawing.Brief Description of the DrawingsFIGS. 1 a- dschematically show embodiments of a residual current protection element according to the invention, comprising two electrical conductors arranged one above the other, each having two recesses. FIGS. 2 a- dschematically show embodiments of an earth leakage protection element according to the invention, comprising two electrical conductors arranged one above the other, each having a central cutout. FIGS. 3 a- b show schematically different arrangement possibilities of the magnetic sensors. FIGS. 4 a- c show schematic embodiments of a residual current protection element according to the invention, comprising two electrical conductors arranged one above the other, each with two recesses which are arranged on opposite sides of the respective conductor. FIGS. 5 a- b show schematic embodiments of a residual current protection element according to the invention, in which the two electrical conductors are arranged next to one another and do not have a cutout. FIG. 6 schematically shows a further embodiment of a residual current protection element according to the invention.Embodiment(s) of the InventionFIG. 1 ashows a schematic exemplary embodiment 100 of a residual current protection element according to the invention with two electrical conductors 101 a, 101 bin a plan view. A first of the two electrical conductors 101 ais formed on a carrier substrate 102, which can be formed, for example, as a printed circuit board.The first electrical conductor 101 aincludes two recesses 103 a, 103 b, which are each arranged at the edge of the first conductor 101 aand mirror-symmetrically to a longitudinal plane 104 aof the first conductor 101 a(the longitudinal plane 104 aruns perpendicularly to the plane of the drawing). Two magnetic sensors 105 a, 105 bare arranged in the recesses 103 a, 103 b, likewise mirror-symmetrically with respect to the longitudinal plane 104 aof the first conductor 101 a. The two magnetic sensors 105 a, 105 bare formed on the carrier substrate 102. The two magnetic sensors 105 a, 105 bare designed or configured to detect a vertical magnetic field B, which runs perpendicular to the main extension plane (which corresponds to the plane of the drawing in FIG. 1 a) of the carrier substrate 102.Furthermore, a cross-sectional plane 106 is drawn in.FIG. 1 bshows the residual current protection element 100 illustrated in FIG. 1 ain a view from below. A second of the two electrical conductors 101 bis arranged on the underside of the carrier substrate 102. The second conductor likewise has two cut-outs 107 a, 107 b, which are situated at the edge and are arranged mirror-symmetrically with respect to a longitudinal plane 104 bof the second conductor 101 b. The recesses 107 a, 107 bof the second conductor 101 bhave in particular the same geometric dimensions as the recesses 103 a, 103 bof the first conductor 101 a. Furthermore, the two conductors 101 a, 101 bare arranged one above the other in cross section (cf. FIG. 1 c ). In particular, the recesses 103 a, 103 bof the first conductor 101 aand the recesses 107 a, 107 bof the second conductor 101 bare also arranged one above the other.In FIG. 1 c, a cross-sectional view and a view of the cross-sectional plane 106 are schematically shown. In this case, the first conductor 101 aand the two magnetic sensors 105 a, 105 bare arranged on the upper side of the carrier substrate 102, while the second conductor 101 bis arranged on the other side or underside of the carrier substrate 102. The longitudinal plane 104 aand the longitudinal plane 104 brun one inside the other or are identical. It can be clearly seen here that the first and second conductors 101 a, 101 bare formed lying one above the other parallel to a main extension plane of the carrier substrate 102 or, if this is arranged horizontally as in the figure. If the residual current protection element has more than two conductors, in particular four conductors, these can be designed as conductor tracks within the printed circuit board in a manner arranged correspondingly one above the other.FIG. 1d shows a schematic representation of a further embodiment of a residual current protection element 100'. The residual current protection element 100' corresponds largely to the residual current protection element 100 from FIGS. 1a to 1c. However, a magnetic flux concentrator, which consists of two magnetic flux concentrator components 108 a, 108 b, is additionally provided here, so that in particular two intermediate spaces are formed. In each of these two intermediate spaces, one of the two magnetic sensors 105 a, 105 bis located.FIG. 2 ashows a further exemplary embodiment of a residual current protection element schematically in a plan view and denoted by 200. Elements identical to those of FIG. 1 are denoted here and in the following figures by the same reference numerals, those functionally corresponding to those of FIG. 1, with a reference numeral increased by 100, 200, 300 and 400, respectively. Analogously to the embodiment 100 illustrated in FIG. 1 a, both a first of the two conductors 201 aand the two magnetic sensors 105 a, 105 bare located on the upper side of the carrier substrate 102.In this exemplary embodiment, only one cutout 203 ais present, which is arranged mirror-symmetrically with respect to a longitudinal plane 204 aof the first conductor 201 a. The two magnetic sensors 105 a, 105 bare located in this recess 203 aand are arranged in particular mirror-symmetrically to the longitudinal plane 204 a.Furthermore, a cross-sectional plane 206 is drawn in.FIG. 2 bshows a schematic view of the residual current protection element 200 illustrated in FIG. 2 afrom below. A second of the two conductors 201 bis formed on the carrier substrate 102 and has a central cutout 207 a, analogous to the cutout 203 ashown in FIG. 2 a, which is arranged in particular mirror-symmetrically to a longitudinal plane 204 bof the second conductor 201 b. The two conductors 201 a, 201 band the corresponding recesses 203 a, 207 aare arranged one above the other in cross section (cf. FIG. 2 c ).FIG. 2 cshows a schematic cross-sectional view or a view of the cross-sectional plane 206 of the fault current protection element 200. The two conductors 201 aand 201 bare arranged here parallel to the main extension plane of the carrier substrate 102 or, if it is arranged horizontally as in the figure, lying one above the other and the two magnetic sensors 105 a, 105 bare located on the upper side of the carrier substrate 102. The longitudinal plane 204 aand the longitudinal plane 204 brun one inside the other or are identical.FIG. 2d shows a schematic representation of a further embodiment of a residual current protection element 200'. The residual current protection element 200' corresponds largely to the residual current protection element 200 from FIGS. 2a to 2c, which is extended by two magnetic flux concentrators 208a, 208b, which can serve in particular for concentrating and conducting the magnetic field. The two magnetic flux concentrators each consist of a magnetic flux concentrator component which is interrupted at one point in each case, so that an intermediate space is formed in each case. In each case one of the two magnetic sensors 105 a, 105 bis located in this respective interspace.FIGS. 3a and 3b schematically show further embodiments 300, 300' of a residual current protection element in cross section. The residual current protection elements 300, 300' largely correspond to the residual current protection element 200 from FIG. 2c, but have a different placement of the two magnetic sensors 105a, 105b. In FIG. 3 a, the two magnetic sensors 105 a, 105 bare integrated or embedded in the carrier substrate 102. In FIG. 3 b, the magnetic sensors 105 a, 105 bare located in a depression 301 of the carrier substrate 102. The depression 301 can be formed in particular on or in a surface which corresponds to the surface of the cutout 202 a.This buried or recessed placement of the magnetic sensors 105a, 105b may also be realized in the leakage current protection elements 100, 100' of FIG. 1.FIG. 4 ashows a further embodiment 400 of a residual current protection element schematically in a plan view of the carrier substrate 102. A first conductor 401 aand the two magnetic sensors 105 a, 105 bare arranged on the upper side of the carrier substrate 102. The first conductor 401 acomprises two recesses 403 a, 403 b, which are located at the edge of the conductor 401 aand are arranged on different sides and different positions with respect to a longitudinal plane 404 aof the conductor 401 a, so that an S-shape of the conductor 401 ais obtained. The two magnetic sensors 105 a, 105 bare arranged in the recesses 403 a, 403 band are cut by the longitudinal plane 404 aof the conductor 401 a.FIG. 4 bshows the underside of the residual current protection element 400 illustrated in FIG. 4 a, on which a second conductor 401 bis arranged. The second conductor, like the first conductor, has two recesses 407 a, 407 b, which are likewise located at the edge of the conductor 401 band are arranged on different sides and different positions with respect to a longitudinal plane 404 bof the conductor 401 b. Both the two conductors 401 aand 401 band also the recesses 403 aand 407 aand the recesses 403 band 407 bare arranged one above the other in cross section (as well as in longitudinal section, cf. FIG. 4 c ).FIG. 4 cshows a longitudinal section along the longitudinal planes 404 a, 404 bof the two conductors according to the representations in FIGS. 4 aand 4 b. The first conductor 401 aand the two magnetic sensors 105 a, 105 bare located on one side (upper side) of the carrier substrate 102, while the second conductor 401 bis applied on the other side (lower side). It can be seen here that both the two conductors 401 aand 401 band the corresponding recesses 403 a, 403 band 407 aand 407 bare arranged lying one above the other parallel to the main extension plane of the carrier substrate 102, or if this is arranged horizontally as in the figure.Here too, the magnetic sensors according to FIGS. 3 aand 3 bmay be embedded or arranged in a depression of the carrier substrate 102.FIG. 5 ashows schematically in a plan view an embodiment of a residual current protection element in which the two conductors 501 a, 501 bare arranged next to one another, running parallel and on the same side of the carrier substrate 102. The two conductors 501 a, 501 bhave no recesses in this embodiment. The two magnetic sensors 105 a, 105 bare respectively located on the conductors or overlap with the conductors (in particular completely) in plan view. The two magnetic sensors 105 a, 105 bare arranged mirror-symmetrically with respect to a central plane 504 between the two conductors 501 a, 501 b. The magnetic sensors 105 a, 105 bare designed or configured for detecting a transverse magnetic field B, which runs perpendicular to the central plane 504 and parallel to the main extension plane of the carrier substrate.Furthermore, a cross-sectional plane 506 is drawn in.FIG. 5 bshows a schematic cross-sectional view or a view of the cross-sectional plane 506 of the embodiment 500 of the fault current protection element illustrated in FIG. 5 a. It can be seen here that both the two conductors 501 aand 501 band also the two magnetic sensors 105 a, 105 bare formed on the same side of the carrier substrate 102 and are arranged mirror-symmetrically with respect to the central plane 504.Here too, the magnetic sensors according to FIGS. 3 aand 3 bmay be embedded or arranged in a depression of the carrier substrate 102, i.e. below the conductors 501 a, 501 b.FIG. 6 shows a further embodiment of a residual current protection element according to the invention. In this case, a first electrical conductor 601 aand a second electrical conductor 601 bare formed as busbars within the carrier substrate 102 or are embedded in the carrier substrate and thereby protected in particular from external environmental influences. The two magnetic sensors 105 a, 105 bare arranged on a surface of the carrier substrate 102 and arranged mirror-symmetrically to a longitudinal plane 604 of the electrical conductors 601 a, 601 b. The magnetic sensors 105 a, 105 bare configured to detect a vertical magnetic field B, which runs parallel to the longitudinal plane 604 of the electrical conductors and perpendicular to the main extension plane of the carrier substrate.The two electrical conductors 601 a, 601 bare designed as current paths and have here a rectangular cross section with two parallel longer sides and two parallel shorter sides standing perpendicular thereon. In addition, the two electrical conductors 601 a, 601 bare arranged such that they extend with their longer sides parallel to one another and also parallel to a connecting line between the two magnetic sensors 105 a, 105 b. Further, the longer side of the electric conductor 601 a, which is closer to the two magnetic sensors 105 a, 105 b, is longer than the longer side of the other electric conductor 601 b. As a result, the magnetic fields generated by a current flow through the electrical conductors 601 a, 601 bare so pronounced that they ideally run parallel at the position of the two magnetic sensors 105 a, 105 band have the same or approximately the same amplitude. As a result, distance-dependent effects of the magnetic field can therefore be compensated for, such that, in particular in the case of a reverse current flow of the same amplitude through the two electrical conductors 601 a, 601 b, no effective magnetic field occurs at the position of the magnetic sensors 105 a, 105 b.

Claims

A residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) for detecting a residual current in electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), the residual current protection element comprising: at least two parallel running electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), a carrier substrate (102) carrying the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), and two magnetic sensors (105a, 105b) connected to generate a differential measurement signal.The fault current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to claim 1, wherein the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are formed as busbars having a cross-sectional shape having two parallel longer sides.The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of the preceding claims, wherein at least one of the two magnetic sensors (105a, 105b) is arranged on a surface of the carrier substrate (102), and / or wherein at least one of the two magnetic sensors (105a, 105b) is integrated into the carrier substrate (102), and / or wherein at least one of the two magnetic sensors (105a, 105b) is arranged in a depression (301) of the carrier substrate (102).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of the preceding claims, wherein the two magnetic sensors (105a, 105b) are arranged on the same surface of the carrier substrate (102).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of the preceding claims, wherein the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are formed on different sides of the carrier substrate (102).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of claims 1 to 4, wherein the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are formed on the same side of the carrier substrate (102).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of claims 1 to 4, wherein at least one of the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) is embedded in the carrier substrate (102).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of the preceding claims, wherein a cross-sectional area of the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) is reduced at at at least one location each, wherein the reduction of the cross-sectional area is formed in the form of at least one recess (103a, 103b, 107a, 107b; 203a, 207a; 403a, 403b, 407a, 407b) each.The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to claim 5 and claim 8, wherein the two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are arranged lying one above the other parallel to a main extension plane of the carrier substrate (102), and wherein the recesses (103a, 103b, 107a, 107b; 203a, 207a; 403a, 403b, 407a, 407b) of the two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are arranged lying one above the other.The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any one of claims 8 or 9, wherein the two magnetic sensors (105a, 105b) are arranged in the at least one recess (103a, 103b, 107a, 107b; 203a, 207a; 403a, 403b, 407a, 407b) of at least one of the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b).The residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to claim 6, wherein, in a plan view of the carrier substrate (102), the two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) are arranged next to each other and the two magnetic sensors (105a, 105b) are arranged on or overlapping with the electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b).Residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to one of the preceding claims, having at least one magnetic flux concentrator (108a, 108b) which encloses at least one of the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b), wherein the at least one magnetic flux concentrator (108a, 108b) has in each case at least one interruption, such that in total at least two intermediate spaces are produced, and wherein the two magnetic sensors (105a, 105b) are in each case arranged in one of the at least two intermediate spaces.A residual current circuit breaker comprising a residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to any of the preceding claims and a breaker configured to interrupt the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) in response to a detected residual current.Method for determining a residual current, wherein a residual current protection element (100, 100'; 200, 200'; 300, 300'; 400; 500; 600) according to one of Claims 1 to 12 is used, comprising the steps of: determining a magnetic field value in each case by means of the two magnetic sensors (105a, 105b), and determining a residual current as a sum of the currents flowing through the at least two electrical conductors (101a, 101b; 201a, 201b; 401a, 401b; 501a, 501b; 601a, 601b) from the two determined magnetic field values.

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