Current sensor system

Abstract

A current sensor system for accurately measuring AC currents with frequencies up to 2 kHz includes: an electrical conductor (e.g., a busbar) for conducting the AC current to create a first magnetic field; a magnetic sensor device for measuring a component or gradient of the magnetic field; and an object (e.g., a metal plate) having a conductive surface disposed near the conductor to allow eddy currents to flow in the surface, thereby creating a second magnetic field superimposed on the first magnetic field; wherein the magnetic sensor device is configured to determine the current as a signal or value proportional to the measured component or gradient. The metal plate may have openings. The current sensor system may further include a shield.

Description

Technical Field

[0001] This invention generally relates to the field of current sensor systems, and more specifically to magnetocurrent sensors. More specifically, this invention relates to a current sensor system capable of accurately measuring AC currents having frequencies up to about 2 kHz. Background Technology

[0002] Different types of current sensors are known in the art, such as (1) current sensors using shunt resistors, (2) current sensors using current transformers, or (3) current sensors using magnetic sensors.

[0003] In current sensors using shunt resistors, the voltage across the shunt resistor is measured, and the current value can be determined by dividing the measured voltage value by the resistance value. A disadvantage of this type is that the measuring circuit is not electrically isolated from the load. Current transformers consist of primary and secondary windings. Although this type of current sensor provides galvanic separation, it is typically bulky. Magnetic-based current sensors provide both current isolation and can be very compact.

[0004] Known current sensors are typically designed to measure DC current or low-frequency current, such as current with a frequency of about 50 Hz or about 60 Hz.

[0005] There are various types of electric motors, such as DC brushed motors, DC brushless motors, AC brushless motors, linear motors, and stepper motors. In electric vehicles, the following motor types are commonly used: DC series motors, brushless DC motors, permanent magnet synchronous motors (PMSM), three-phase AC induction motors, and switched reluctance motors (SRM).

[0006] Various circuits exist for driving and / or controlling and / or monitoring electric motors. In some of these circuits, it is necessary to measure the actual current supplied to the motor. These currents may be on the order of tens or even hundreds of amperes and may have frequencies or frequency components up to several kHz. These currents are typically supplied to the motor via so-called "busbars." Busbars typically appear in the form of metal strips or bars, such as copper bars.

[0007] It is known that when an AC current flows through an electrical conductor, a phenomenon known as the "skin effect" occurs. This leads to an increase in the effective resistance of the conductor. The higher the frequency of the current, the higher the effective resistance of the conductor.

[0008] Measuring AC current with high accuracy is a challenge. Summary of the Invention

[0009] The purpose of embodiments of the present invention is to provide a current sensor system for measuring AC current (e.g., AC current flowing through a busbar).

[0010] The purpose of embodiments of the present invention is to provide a current sensor system for measuring AC current with improved accuracy.

[0011] The purpose of embodiments of the present invention is to provide a current sensor system for measuring AC currents with frequencies up to 2 kHz with improved accuracy.

[0012] The purpose of embodiments of the present invention is to provide a current sensor system for measuring the instantaneous amplitude or momentary amplitude of AC current having a frequency of up to 2 kHz with improved accuracy.

[0013] The purpose of embodiments of the present invention is to provide a current sensor system for measuring AC current in a simple manner with improved accuracy, for example, without requiring the performance of spectral analysis (e.g., Fourier analysis) and / or without requiring the analysis of the current waveform (e.g., sine, square, triangular) in the time domain.

[0014] The object of embodiments of the present invention is to provide a current sensor system capable of measuring AC current with absolute accuracy within + / -5%, or within + / -4%, or within + / -3%, or within + / -2%, or within + / -1%, the AC current having one or more frequencies (or spectral components) in the range of about 100 Hz to about 2000 Hz.

[0015] These and other objectives are achieved by a current sensor according to an embodiment of the present invention.

[0016] According to a first aspect, the present invention provides a current sensor system for measuring an AC current having a frequency within a predefined frequency range, the system comprising: an electrical conductor configured to conduct the AC current thereby creating a first magnetic field; a magnetic sensor device configured to measure a magnetic field component or magnetic field difference; the current sensor system further comprising a metal plate or conductive surface disposed near the electrical conductor to allow eddy currents to flow in the surface thereby creating a second magnetic field superimposed on the first magnetic field; wherein the magnetic sensor device is configured to determine the magnitude of the AC current as a signal or value proportional to the measured magnetic field component or the magnetic field gradient.

[0017] One advantage of this current sensor system is that it allows for accurate measurement of AC currents, which can have frequencies up to about 2 kHz, in a fast and simple manner, without requiring cumbersome processing or performing spectral analysis techniques (e.g., Fourier analysis).

[0018] The inventors discovered that by adding a conductive surface (e.g., a metal plate or a copper layer on a printed circuit board (PCB), AC current can be measured with improved accuracy. The inventors were surprised to find that the magnetic field introduced by eddy currents could improve accuracy; this was completely unexpected and highly counterintuitive, as it is well known and generally accepted / believed that eddy currents negatively impact, rather than improve, measurement results.

[0019] Compared to systems that measure the peak current and then multiply that peak current by, for example, 1.41 (the square root of 2), an advantage of this invention is that the AC current is determined by multiplying the measured magnetic field gradient or magnetic field components, since the system of multiplying the peak current by 1.41 is only accurate when the AC current waveform is a perfectly sinusoidal signal. Another advantage of this invention is that the measurement results are accurate for any AC waveform (e.g., sinusoidal, square, triangular, etc.).

[0020] In the example, the sensor device has a first magnetic sensor located at a first sensor location and a second magnetic sensor located at a second sensor location. The second magnetic field (i.e., the field caused by eddy currents) has the same direction as the first magnetic field (i.e., the field caused by current flowing in an electrical conductor (e.g., a busbar)) at the first sensor location, and the second magnetic field has the opposite direction to the first magnetic field at the second sensor location.

[0021] The conductive surface can be separated from the current of the electrical conductor and the magnetic sensor device.

[0022] A conductive surface can be substantially planar, or it can have planar portions. For example, an object can be a conductive plate, such as a copper plate or an aluminum plate.

[0023] In an embodiment, the magnetic sensor device is configured to determine the amplitude of an AC current at a frequency of at least 5.0 kHz, or at least 8 kHz, or at least 10 kHz.

[0024] Preferably, the current sensor system is a coreless sensor system.

[0025] In one embodiment, the sensor device is positioned at a location where the superposition of the first magnetic field and the second magnetic field has a substantially constant magnitude over a frequency range from 100 Hz to 2 kHz.

[0026] "Substantially constant" means within a predefined tolerance margin, such as less than + / -4%, or less than + / -3%, or less than + / -2%.

[0027] Positioning the sensor device within the frequency range of the superimposed frequency range has the effect that the total magnetic field seen by the sensor device will be substantially constant in frequency, thereby minimizing the error between the determined AC current and the actual AC current.

[0028] In most embodiments, size and dimensions are not critical, as long as they are “large enough” compared to the dimensions of the electrical conductor. For example, the size of the metal plate or conductive surface can be rectangular, although this is not absolutely necessary, and it is sufficient that the length and width of the metal plate or conductive surface are on the same order of magnitude as the width of the busbar.

[0029] In the embodiment, at least 90%, or at least 95%, or at least 96%, or at least 97%, or at least 98%, or at least 99% of the power of the AC current is below 2000 Hz.

[0030] In this embodiment, the magnetic sensor device is an integrated semiconductor device (also referred to as a “chip”), and electrical conductors are arranged on the exterior of the integrated semiconductor device.

[0031] In the embodiments, the conductive surface is a metal sheet or a metal layer.

[0032] In other words, in this embodiment, the current system includes: an electrical conductor, a magnetic sensor device, and a metal plate or sheet, which is made of, for example, copper or a copper alloy, or, for example, aluminum or an aluminum alloy.

[0033] In an embodiment, the magnetic sensor device is configured to measure a first magnetic field component at a first sensor location, and to measure a second magnetic field component (parallel to the first magnetic field component) at a second sensor location spaced apart from the first sensor location, and to determine a magnetic field difference or magnetic field gradient based on the difference between the first magnetic field component and the second magnetic field component; and to determine the magnitude of the AC current according to the formula: I = K * (ΔBz), where I is the magnitude of the AC current to be measured, K is a predefined constant independent of frequency, and ΔBz is the magnetic field difference or magnetic field gradient.

[0034] In an embodiment, the magnetic sensor device is configured to measure a first magnetic field component at a first sensor location and to determine the magnitude of the AC current according to the formula: I = K * (Bz), where I is the magnitude of the AC current to be measured, K is a predefined constant independent of frequency, and Bz is the first magnetic field component being measured.

[0035] In this embodiment, the magnetic sensor device is configured to determine the AC current as a value proportional to the magnetic field component value.

[0036] In one embodiment, the current sensor system further includes a shield.

[0037] In an embodiment, the sensor device and the electrical conductor, as well as the metal plate (or conductive surface or layer), are arranged relative to each other such that the current value obtained by one of the above formulas provides substantially the same result for a first sinusoidal current having a predefined amplitude and a frequency of 100 Hz and a second sinusoidal current having the same predefined amplitude and a frequency of 2000 Hz, within a predefined tolerance margin of + / -4% or + / -3% or + / -2% or + / -1%.

[0038] In one embodiment, the electrical conductor includes a first bundle of conductor portions and a second bundle of conductor portions, both extending in a longitudinal direction and spaced apart from each other to form a gap between them; and wherein a metal plate or conductive surface is arranged parallel to the electrical conductor and at a predefined distance from the electrical conductor to form a gap or slit between them; and wherein a magnetic sensor device is arranged within the gap or slit.

[0039] This gap is shown, for example, by the dashed area in Figures 1(d) and 1(f).

[0040] In one embodiment, the magnetic sensor device is configured to measure the first magnetic field component and the second magnetic field component, both of which are oriented in the height direction of the electrical conductor; and the first sensor position and the second sensor position are spaced apart in the lateral direction.

[0041] The current sensor device may have a semiconductor substrate oriented parallel to the surface and may include two horizontal Hall plates spaced apart by a distance dx, the distance dx being in the range of 1.0 mm to 2.5 mm, or 1.5 mm to 2.5 mm, or 1.5 mm to 2.2 mm, for example, equal to about 1.9 mm. The current sensor device may be arranged such that its semiconductor substrate is located at a height position (in the Z direction) at substantially the middle position of the thickness of the bundle conductor portion (e.g., at Tc / 2).

[0042] In an embodiment, the magnetic sensor device is configured to measure the first magnetic field component and the second magnetic field component, both of which are oriented in the lateral direction of the electrical conductor; and the first sensor position and the second sensor position are spaced apart in the height direction of the electrical conductor.

[0043] In one embodiment, the magnetic sensor device has a semiconductor substrate and is arranged such that its semiconductor substrate is oriented perpendicular to the metal plate or conductive surface and is substantially located in the middle between two bundle-shaped conductor portions.

[0044] A magnetic sensor device may include two horizontal Hall plates spaced apart by a distance (dz) in the range of 1.0 mm to 2.5 mm, or 1.5 mm to 2.5 mm, or 1.5 mm to 2.2 mm, for example, approximately 1.9 mm.

[0045] In one embodiment, the electrical conductor has an elongated shape extending in a first direction and a width extending in a transverse direction perpendicular to the first direction; and the electrical conductor includes a first cut and a second cut, the first cut extending from a first side of the electrical conductor for more than half of the transverse width, the second cut extending from a second side of the electrical conductor for more than half of the transverse width, the first cut and the second cut defining a transverse channel region between them; and a metal plate or conductive surface has an opening or a non-conductive region located near the transverse channel region; and the metal plate or conductive surface is located at a first distance from the electrical conductor; and a magnetic sensor device is arranged near the opening or the non-conductive region, at a second distance from the electrical conductor that is less than, greater than, or substantially equal to the first distance (g).

[0046] In other words, three scenarios are envisioned. In the first scenario, as shown in Figure 4(c), the sensor device is located "between" the electrical conductor (e.g., a busbar) and the conductive surface (e.g., a metal plate). In the second scenario, as shown in Figure 4(d), the metal plate or conductive surface is located in the plane between the electrical conductor (e.g., the busbar) and the sensor device, or in other words, the sensor device is located "above" the metal plate. In the third scenario, as shown in Figure 4(e), the sensor device is substantially located in the same (virtual) plane as the metal plate or conductive surface.

[0047] The opening can be a through hole that passes through the metal plate.

[0048] The opening or non-conductive area can have a square or rectangular shape. The length and width of the opening can be in the range of about 50% to about 150%, or about 90% to about 150%, or about 100% to about 150% of the distance dx between the Hall elements. For example, if dx = 2.0 mm, the length of the opening can be about 2.0 mm to about 3.0 mm, and the width can be about 2.0 mm to about 3.0 mm.

[0049] In an embodiment, the magnetic sensor device is configured to measure the first magnetic field component and the second magnetic field component, both oriented in the height direction (or “thickness direction”) of the electrical conductor; and the first sensor position and the second sensor position are spaced apart in the longitudinal direction of the electrical conductor.

[0050] The magnetic sensor device may have a semiconductor substrate oriented parallel to the upper surface of an electrical conductor facing a conductive surface, and preferably located "above" the transverse channel region between two cutouts.

[0051] The magnetic sensor device may include two horizontal Hall plates spaced apart by a distance ranging from 1.0 mm to 2.5 mm, or 1.5 mm to 2.5 mm, or 1.5 mm to 2.2 mm, for example, approximately 1.9 mm. The magnetic sensor may be configured to measure the magnetic field gradient (dBz / dy) oriented in a direction perpendicular to the semiconductor substrate along the longitudinal direction (Y) of the electrical conductor.

[0052] In one embodiment, the current sensor device includes two sensor devices mounted on a printed circuit board. A first sensor device is configured to determine a first current, and a second sensor device is configured to determine a second current. The PCB may be oriented substantially parallel to or perpendicular to a metal plate or conductive surface. Each sensor device may include two horizontal Hall elements configured to determine a magnetic field gradient dBz / dy oriented in the Z-direction along the Y-direction, as shown in Figure 4(e). Each sensor device may also include two vertical Hall elements configured to determine a magnetic field gradient dBz / dy oriented in the Z-direction along the Y-direction, as shown in Figure 4(h). Such embodiments provide redundancy and are particularly suitable for functional safety applications.

[0053] In an embodiment, the electrical conductor has an elongated shape extending in a first direction and a width extending in a transverse direction perpendicular to the first direction; and the electrical conductor includes a first cut and a second cut, the first cut extending from a first side of the electrical conductor beyond at least half of the transverse width, the second cut extending from a second side of the electrical conductor beyond at least half of the transverse width, the first cut and the second cut defining a transverse channel region between them; and a metal plate or conductive surface is parallel to the electrical conductor and located on only one side of an imaginary plane oriented perpendicular to the first direction and in the middle between the first cut and the second cut; and the metal plate or conductive surface is located at a first distance from the electrical conductor; and a magnetic sensor device is arranged near the transverse channel region at a second distance from the electrical conductor that is less than, greater than, or substantially equal to the first distance (g).

[0054] In an embodiment, the magnetic sensor device is configured to measure the first magnetic field component at a first sensor location and the second magnetic field component at a second sensor location, both oriented in the height direction of the electrical conductor; and the first sensor location and the second sensor location are spaced apart in the longitudinal direction.

[0055] The magnetic sensor device may have a semiconductor substrate oriented parallel to the upper surface of an electrical conductor facing a conductive surface, and preferably located "above" the transverse channel region between two cutouts.

[0056] The magnetic sensor device may include two horizontal Hall plates spaced apart by a distance ranging from 1.0 mm to 2.5 mm, or 1.5 mm to 2.5 mm, or 1.5 mm to 2.2 mm, for example, approximately 1.9 mm. The magnetic sensor may be configured to measure the magnetic field gradient (dBz / dy) oriented along the longitudinal direction (Y) of the electrical conductor in, for example, a direction perpendicular to the height (Z) of the metal plate.

[0057] In one embodiment, the orthogonal projection of at least one or both magnetic sensor elements onto a virtual plane comprising a metal plate or conductive surface lies outside the metal plate (or conductive surface). Alternatively, in this embodiment, one or two imaginary lines passing through the magnetic sensor elements and orthogonal to the metal plate (or conductive surface) do not intersect the metal plate (or conductive surface).

[0058] In one embodiment, the electrical conductor has an elongated shape extending in a first direction and a width extending in a transverse direction perpendicular to the first direction; and the current sensor system further includes a magnetic shield that completely surrounds a portion of the electrical conductor or forms a bridge over a portion of the electrical conductor; and a metal plate or conductive surface is oriented parallel to the electrical conductor and located at a first distance from the electrical conductor, thereby defining a gap between them; and a magnetic sensor device is disposed in the gap between the portion of the electrical conductor and the conductive surface.

[0059] Electrical conductors can have a bundle shape and a rectangular cross-section.

[0060] A metal plate or conductive surface may be part of or adjacent to the shielding element. The shielding element may be U-shaped, V-shaped, or Ω-shaped, as shown in Figure 8(a).

[0061] The shield can be isolated from the current on the conductive surface, or it can be in contact with the current on the conductive surface.

[0062] In one embodiment, the magnetic sensor device is configured to measure a magnetic field component oriented in the transverse direction of the electrical conductor.

[0063] Magnetic sensor devices may have vertical Hall elements or disk-shaped integrated magnetic concentrators (IMCs) with two horizontal Hall elements arranged on the periphery of the IMC.

[0064] In the embodiments, the conductive surface includes one or more conductive layers, such as one or more copper layers of a printed circuit board, and at least one of the following is effective:

[0065] (i) The thickness of the conductive surface is a value in the range of about 30 μm to about 220 μm (e.g., equal to about 35 μm, or equal to about 105 μm, or equal to about 200 μm); and / or

[0066] (ii) The distance between the conductive surface and the magnetic sensing element can be in the range of 0.2 mm to 5.0 mm or 0.2 mm to 3.0 mm; and / or

[0067] (iii) The dimensions of the conductive surface (e.g., the length and width of a rectangular shape) may be in the range of Wc* (50% to 500%) or in the range of Wc* (50% to 300%), where Wc is the width of the electrical conductor (e.g., the width of a busbar).

[0068] In this embodiment, the conductive surface is part of a (e.g., a solid) metal plate, and at least one of the following is effective:

[0069] (i) The thickness of the conductive surface may be in the range of approximately 0.5 mm to 10 mm or 0.5 mm to 5.0 mm; and / or

[0070] (ii) The distance between the conductive surface and the magnetic sensing element can be in the range of 0.5 mm to 10 cm or 0.5 mm to 5.0 cm; and / or

[0071] (iii) The dimensions of the conductive surface (e.g., the length and width of a rectangular shape) may be in the range of Wc* (50% to 500%) or in the range of Wc* (50% to 300%), where Wc is the width of the electrical conductor (e.g., the width of a busbar).

[0072] According to another aspect, the present invention also relates to a three-phase current sensor system for measuring a three-phase AC current having a frequency within a predefined frequency range, the system comprising: a first electrical conductor and a first magnetic sensor device, the first electrical conductor being configured to conduct a first AC current thereby creating a first magnetic field, the first magnetic sensor device being configured to measure a first magnetic field component or a first magnetic field difference of the first magnetic field; a second electrical conductor and a second magnetic sensor device, the second electrical conductor being configured to conduct a second AC current thereby creating a second magnetic field, the second magnetic sensor device being configured to measure a second magnetic field component or a second magnetic field difference of the second magnetic field; a third electrical conductor and a third magnetic sensor device, the third electrical conductor being configured to conduct a third AC current thereby creating a third magnetic field, the third magnetic sensor device being configured to measure a third magnetic field component or a third magnetic field difference of the third magnetic field; wherein the current sensor system further comprises a first metal plate or a first conductive surface disposed near the first electrical conductor to allow eddy currents to flow in the first plate or the first surface thereby creating a fourth magnetic field superimposed on the first magnetic field;

[0073] The system further includes a second metal plate or a second conductive surface disposed near the second electrical conductor to allow eddy currents to flow in the second plate or the second surface, thereby creating a fifth magnetic field superimposed on the second magnetic field; and further includes a third metal plate or a third conductive surface disposed near the third electrical conductor to allow eddy currents to flow in the third plate or the third surface, thereby creating a sixth magnetic field superimposed on the third magnetic field; wherein a first magnetic sensor device is configured to determine the magnitude of a first AC current as a signal or value proportional to the measured first magnetic field component or the first magnetic field gradient; wherein a second magnetic sensor device is configured to determine the magnitude of a second AC current as a signal or value proportional to the measured second magnetic field component or the second magnetic field gradient; and wherein a third magnetic sensor device is configured to determine the magnitude of a third AC current as a signal or value proportional to the measured third magnetic field component or the third magnetic field gradient.

[0074] Specific and preferred aspects of the invention are set forth in the appended independent and dependent claims. Features from the dependent claims may be suitably combined with features of the independent claims and other dependent claims, and not merely as expressly set forth in the claims.

[0075] These and other aspects of the invention will be apparent from the embodiments described herein, and are illustrated with reference to these embodiments. Attached Figure Description

[0076] Figures 1(a) to 1(d) A first embodiment of a current sensor system according to the invention is shown, wherein the current sensor system includes two electrical conductor portions spaced apart from each other to form a gap therebetween, and wherein a magnetic sensor device is substantially disposed within said gap, and wherein a metal plate is disposed near the electrical conductors. Figure 1(b) shows a top view of the electrical conductors, Figure 1(a) shows a cross-sectional view of the sensor system in plane AA of Figure 1(b), Figure 1(c) shows a perspective view, and Figure 1(d) shows a front view.

[0077] Figures 1(e) to 1(f) Another embodiment of the invention is shown in Figures 1(a) to 1(d) The variant of the system shown in the figure.

[0078] Figure 2(a) shows the situation where a metal plate is not present, such as when it can be obtained by... Figures 1(a) to 1(d) The simulation results are obtained by measuring the amplitude and phase of the magnetic field component Bx, which is a complex representation of the magnetic field induced by a sinusoidal AC current at different positions along the X-axis at different frequencies, using the sensor elements of the sensor device.

[0079] Figure 2(b) shows the simulation results in the presence of a metal plate.

[0080] Figure 3(a) shows the process without a metal plate, by Figures 1(a) to 1(d) How the signal measured by the sensor element will attenuate and phase shift as a function of frequency.

[0081] Figure 3(b) shows the situation in the presence of a metal plate, where... Figures 1(a) to 1(d) The sensor element measures how the signal will decay and phase shift as a function of frequency. As shown in the figure, the differential signal or gradient signal has a substantially constant amplitude and a phase shift that is substantially zero, regardless of the frequency of the AC current (at least for frequencies from about 100 Hz to about 2000 Hz).

[0082] Figures 4(a) to 4(h) A second embodiment and variations thereof of a current sensor system according to the invention are shown, wherein the current sensor system includes an elongated electrical conductor (e.g., a busbar) having two transverse cuts spaced apart from each other in the overall longitudinal direction of the busbar to form a zigzag shape with transverse channel regions, and further includes a magnetic sensor device disposed near said channel regions, and a metal plate with an opening also disposed near said channel regions.

[0083] Figure 5(a) shows the simulation results of the real and imaginary parts of the magnetic field component Bz induced by the sinusoidal AC current at different positions on the longitudinal Y-axis for different frequencies, as measured by the sensor element of the sensor device in Figure 4, in the absence of a metal plate.

[0084] Figure 5(b) shows the simulation results in the presence of a metal plate.

[0085] Figures 6(a) to 6(g) A third embodiment of the current sensor system according to the invention is shown, wherein the current sensor system includes an elongated electrical conductor (e.g., a busbar) having two transverse cuts spaced apart from each other in the longitudinal direction to form a zigzag shape with transverse channel regions, a magnetic sensor device disposed near said channel regions, and a metal plate with edges asymmetrically disposed near the channel regions. Figure 6(b) shows a top view of the electrical conductor; Figure 6(a) shows a cross-section of Figure 6(b) according to AA; Figure 6(c) shows a top view of an exemplary metal plate; Figure 6(d) shows... Figures 6(a) to 6(c) A top view of an example current sensor system, and an example of eddies flowing in such a plate is shown; Figures 6(e) to 6(g) A perspective view of an example of the current sensor system shown in Figure 6 is presented.

[0086] Figure 7 shows the simulation results of the current sensor system in Figure 6.

[0087] Figure 7(a) shows the real part of the magnetic field component signal Bz as a function of position along the longitudinal axis of the busbar for various AC current frequencies.

[0088] Figure 7(b) shows the imaginary part of the magnetic field component signal Bz.

[0089] Figures 8(a) to 8(c) A fourth embodiment of the current sensor system according to the invention is shown, wherein the current sensor system includes an elongated electrical conductor (e.g., a busbar) with a U-shaped shield, a metal plate, and a magnetic sensor device disposed within a space defined by the metal plate and the shield. Figure 8(a) shows a cross-section of the current sensor system, and Figure 8(b) shows a perspective view of the system without the magnetic shield. Figure 8(c) is a schematic representation of a magnetic sensor device with a vertical Hall sensor, as can be used in the system of Figure 8(b).

[0090] Figure 9 An exemplary block diagram of a circuit that can be used in embodiments of the present invention is shown.

[0091] Figure 10 An exemplary block diagram of a circuit that can be used in embodiments of the present invention is shown.

[0092] The accompanying drawings are illustrative only and not restrictive. In the drawings, some elements may be enlarged and not drawn to scale for illustrative purposes. No reference numerals in the claims should be construed as limiting. In different drawings, the same reference numerals refer to the same or similar elements. Detailed Implementation

[0093] The invention will be described with reference to specific embodiments and particular drawings, but the invention is not limited thereto but is defined only by the claims. The described drawings are merely illustrative and not restrictive. In the drawings, some elements may be enlarged and not drawn to scale for illustrative purposes. Dimensions and relative dimensions do not correspond to an actual reduction in the practice of the invention.

[0094] Furthermore, the terms first, second, etc., used in the specification and claims are used to distinguish between similar elements and are not necessarily used to describe an order in time, space, rank, or any other way. It should be understood that the terms thus used are interchangeable where appropriate, and the embodiments of the invention described herein can be operated in a different order than that described or illustrated herein.

[0095] Furthermore, the terms "top," "below," etc., used in the specification and claims are for descriptive purposes and are not necessarily used to describe relative positions. It should be understood that such terms are interchangeable where appropriate, and that embodiments of the invention described herein can operate in orientations different from those described or illustrated herein.

[0096] It should be noted that the term "comprising" as used in the claims should not be construed as limiting itself to the devices listed thereafter; it does not exclude other elements or steps. Therefore, the term should be interpreted as specifying the presence of the features, integers, steps, or components stated as mentioned, but does not exclude the presence or addition of one or more other features, integers, steps, or components, or groups thereof. Thus, the scope of the statement "device comprising devices A and B" should not be limited to a device consisting solely of components A and B. It means that for the purposes of this invention, the only relevant components of the device are A and B.

[0097] Throughout this specification, the reference to "an embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with that embodiment is included in at least one embodiment of the invention. Therefore, the phrase "in one embodiment" or "in an embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, but may refer to the same embodiment. Furthermore, in one or more embodiments, as will be obvious to those skilled in the art from this disclosure, particular features, structures, or characteristics can be combined in any suitable manner.

[0098] Similarly, it should be understood that in the description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, drawing, or description for the purpose of simplifying the disclosure and aiding in the understanding of one or more inventive aspects. However, this method of disclosure should not be construed as reflecting an intention to claim more features than are expressly recited in each claim. Rather, as reflected in the appended claims, inventive aspects exist in fewer features than all the features of a single foregoing disclosed embodiment. Therefore, the claims appended following the detailed description are thus explicitly incorporated into this detailed description, wherein each claim itself represents a separate embodiment of the invention.

[0099] Furthermore, as will be understood by those skilled in the art, although some embodiments described herein include some features included in other embodiments but not others included in other embodiments, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the appended claims, any claimed embodiment may be used in any combination.

[0100] Numerous specific details are set forth in the description provided herein. However, it should be understood that embodiments of the invention can be practiced without these specific details. In other instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

[0101] In this document, the terms "current sensor system" or "current sensor arrangement" have the same meaning. They refer to a system or arrangement that includes an electrical conductor (e.g., a busbar) for conducting current, a current sensor device for measuring that current, and a conductive surface (e.g., a metal plate or metal layer of a printed circuit board).

[0102] Complex numbers can be represented by amplitude and phase, or by real and imaginary parts. For example, the complex number “1+i” can also be represented by a vector with an amplitude of √2 and a phase of 45°.

[0103] In this document, the term "magnetic gradient" dBz / dy refers to the spatial gradient of the magnetic field component Bz along the Y direction. In practice, dividing by dy is usually omitted.

[0104] In this document, the term "magnetic field difference" ΔBz is used to indicate the difference between two parallel-oriented magnetic field components.

[0105] In this document, the terms “magnetic gradient” and “magnetic difference” are used interchangeably unless otherwise explicitly mentioned or clearly indicated from the context.

[0106] This invention relates to a current sensor based on a magnetic sensor, also known as a "magnetic current sensor," which can be used in industrial or automotive applications (e.g., for measuring one or more currents supplied to an electric motor in, for example, an electric vehicle or a hybrid vehicle). Such motors can be driven by relatively large AC currents, such as substantially sinusoidal currents with amplitudes of tens or even hundreds of amperes. This invention is particularly concerned with accurately measuring such AC currents.

[0107] As mentioned in the background section, it is known that when an AC current flows through an electrical conductor, a phenomenon known as the "skin effect" occurs. This leads to an increase in the effective resistance of the conductor. The higher the frequency of the current, the higher the effective resistance of the conductor.

[0108] The inventors of this invention aim to provide a sensor system capable of measuring AC current flowing through an electrical conductor (e.g., a busbar) with improved AC accuracy. The busbar may be a busbar comprising two parallel conductor portions having a gap (or slit) therebetween, as shown in FIG1(b), or the busbar may be a busbar having a zigzag shape formed by two transverse cuts, as shown in FIG4(f) or FIG6(b). For example, the AC current may be a sinusoidal current having any frequency from, for example, 100 Hz to, for example, 2000 Hz.

[0109] One particular problem that arises when attempting to measure currents at relatively high frequencies (e.g., above 50 Hz or 60 Hz) is the occurrence of a phenomenon known as the "skin effect," which causes the current density to increase near the outer periphery of the conductor and decrease near the center. The inventors have discovered that this not only alters the effective resistance of the busbar but also changes the magnetic field around the conductor. However, to the inventors' knowledge, the way the skin effect alters the magnetic field around the conductor cannot be easily described. This effect becomes increasingly pronounced as the frequency of the AC current increases toward 2000 Hz, and determining the AC current as proportional to the measured magnetic field component or the measured magnetic field gradient without any correction will result in an error, typically on the order of about 10%.

[0110] Because the error (and therefore the correction) is frequency-dependent, the logical approach would be to analyze the frequency content of the AC signal to be measured and correct the measured values ​​accordingly. However, performing frequency analysis (e.g., via Fourier transform) has several drawbacks, such as requiring considerable processing power, the need to use sampling windows typically with at least 16 or 32 samples, which introduces delays, etc., which are disadvantageous, especially in motor control. The inventors wanted to find an alternative solution and began experimenting.

[0111] In short, they conceived the idea of ​​improving the accuracy of the measurements by adding a metal plate near the system. Although they expected this would actually worsen the results, they were surprised to find that adding the metal plate could improve the accuracy of the measurements.

[0112] This result is highly counterintuitive. Indeed, while it is known that if a metal plate is close enough to an electrical conductor, the magnetic field generated by the AC current flowing through that conductor (e.g., a busbar) will cause eddy currents to flow within the metal plate, and these eddy currents will typically generate a second magnetic field that cancels out the original magnetic field, the paths and strengths of such eddy currents are not well defined, and even worse, the magnetic fields generated by these eddy currents are not well defined. However, the inventors were surprised to find that these eddy currents can actually improve the accuracy of AC measurements, meaning that in these current sensor systems, eddy currents can reduce (e.g., significantly reduce) or even almost completely compensate for the negative effects of the skin effect. To the inventors' knowledge, both the "skin effect" and "eddy currents" are generally considered "unwanted effects" or "interference effects" rather than "helpful effects," and it is unknown that one of these can reduce the negative effects of the other in a system. However, this is precisely what the present invention utilizes. This is one idea within the basic concept of the invention.

[0113] Or, in slightly other words, the present invention provides a current sensor system for measuring AC current having frequencies within a predefined frequency range (e.g., from DC to up to 2000 Hz, or from 100 Hz to 2000 Hz). Alternatively, the present invention provides a current sensor system for measuring AC current having a spectrum having spectral peaks or spectral components comprising a significant portion of the signal power (e.g., at least 1%, or at least 2%, or at least 3%, or at least 4%, or at least 5%, or at least 8%, or at least 10%, or at least 15%, or at least 20%, or at least 25%, or at least 30%, or at least 40% of the total power), the signal power being located in the range of about 100 Hz to about 2000 Hz.

[0114] The system includes an electrical conductor (e.g., a busbar) for conducting the AC current, thereby creating a first magnetic field. The system further includes a magnetic sensor device configured to measure at least one characteristic of the magnetic field, such as a magnetic field component, magnetic field difference, or magnetic field gradient. The current sensor system further includes an object with a conductive surface (e.g., a printed circuit board (PCB) or a metal plate, such as a copper or aluminum plate), disposed near the electrical conductor (e.g., the busbar) to allow eddy currents to flow in the surface, thereby creating a second magnetic field superimposed on the first magnetic field. The magnetic sensor device is further configured to determine a signal or value of magnitude (e.g., the instantaneous magnitude of the AC current) proportional to the measured magnetic field component or the magnetic field gradient.

[0115] One advantage of this current sensor system is that it allows for accurate measurement of AC currents, which can have one or more frequencies up to about 2 kHz, in a fast and simple manner, without requiring cumbersome processing or performing spectral analysis techniques (e.g., Fourier analysis).

[0116] The inventors discovered that by adding a conductive surface near the busbar, AC current can be measured with improved accuracy. The inventors were surprised to find that the magnetic field induced by eddy currents could improve accuracy, which was completely unexpected, as it is well known and generally accepted / believed that eddy currents negatively impact, rather than improve, measurement results.

[0117] The advantage of this invention is that the instantaneous value of the AC current can be determined without knowing the waveform's spectrum or its shape in the time domain (e.g., sine wave, square wave, block wave, triangle, or sawtooth shape, etc.).

[0118] While the object may be a solid metal sheet, such as a solid metal plate (e.g., with a thickness in the range of 1 mm to 5 mm, or 1 mm to 50 mm), or may include, for example, a copper layer of a printed circuit board (PCB) with a typical thickness in the range of 30 μm to 40 μm, or may include multiple printed circuit boards (PCBs) of three (or two or four or more) layers, each with a thickness in the range of 30 μm to 40 μm, thereby forming a total thickness of about 3 × 35 μm = about 105 μm, or other objects having a conductive layer or conductive coating, for ease of description, the invention will be described assuming that the object is a metal sheet, but the invention is not limited thereto.

[0119] The conductive surface is preferably isolated from the electrical conductor and the current of the magnetic sensor device (e.g., its supply voltage or ground voltage).

[0120] The conductive surface may be substantially planar, or may have substantially planar portions. In some embodiments, the conductive surface may have non-conductive portions, or the metal plate may have openings, as will be described further.

[0121] Now refer to the attached diagram.

[0122] Figures 1(a) to 1(d) A first embodiment of a current sensor system 100 according to the present invention is shown, comprising an electrical conductor 101, a magnetic sensor device 102, and a metal plate 103. The electrical conductor 101 includes two electrical conductor portions 101a and 101b, spaced apart from each other to form a gap 104 (or opening, through-hole, or slit) therebetween. The magnetic sensor device 102 is substantially disposed within said gap or opening. The metal plate 103 is disposed near the electrical conductor portions 101a and 101b, for example, at a distance of about 1 mm to about 10 cm from a busbar, or at a distance of about 3 mm to about 3 cm. In the example of Figure 1(b), the cross-section of the first conductor portion 101a is the same size as the cross-section of the second conductor portion 101b, so each conductor portion will carry 50% of the total current I through the electrical conductor 101. However, the invention is not limited to this, and another cross-sectional ratio can also be used, for example, a ratio in the range of about 20% to about 80%, or about 30% to about 70%, or about 40% to about 60%. The current sensor device is not shown in Figure 1(a), but see, for example, Figure 1(c) or Figure 1(d).

[0123] Figure 1(b) shows a top view of a portion of the electrical conductor 101. The sensor device and metal plate are not shown in Figure 1(b), but see, for example, Figures 1(c) and 1(d).

[0124] Figure 1(a) shows a cross-sectional view of the sensor system in plane AA of Figure 1(b). In this example, both conductor portions have rectangular cross-sections, but the invention is not limited thereto and other cross-sections (e.g., circular) can also be used. Figure 1(a) also shows field lines and magnetic field vectors (black arrows) at various locations within the gap 104 between the two conductor portions. As mentioned above, when an AC current flows through the conductor portions 101a, 101b, a time-varying magnetic field will be created by the current, and eddy currents will flow in the metal plate, which will create a second magnetic field. However, as mentioned above, the actual path or magnitude of the eddy currents or magnetic field thus created is not precisely known and is not easily described mathematically. How these eddy currents can improve the accuracy of the measurement results will be discussed further (e.g., in Figures 2 and 3), but first the physical arrangement of the various components of the system will be described.

[0125] Figure 1(c) shows a perspective view of a current sensor system 100, in which a metal plate is represented as a semi-transparent rectangle. Also shown is a magnetic sensor device in the form of a packaged integrated circuit 102 arranged between two conductor portions 101a, 101b. The magnetic sensor device 102 shown in Figure 1(c) includes a semiconductor substrate having two horizontal Hall elements (indicated by black squares) spaced apart by a predefined distance dx in the transverse direction X of the electrical conductor 101 (in fact, as can be seen in Figure 1(b), the electrical conductor extends in the Y direction perpendicular to the X direction).

[0126] Figure 1(d) shows a front view of the current sensor system 100. A metal plate may be positioned at a distance “g” from the top of the busbar at least 0.5 mm or at least 1.0 mm. Preferably, the distance g is less than 10 cm or less than 5 cm.

[0127] The magnetic sensor device 102 can be configured to measure a first magnetic field component Bz1 oriented in the Z direction using a first horizontal Hall element H1, and to measure a second magnetic field component Bz2 using a second horizontal Hall element H2 spaced laterally from the first horizontal Hall element H1. The sensor device 102 can be configured to determine the difference ΔBz between these two values, for example, according to the formula: ΔBz = Bz1 - Bz2. It can be further configured to determine the magnitude of the AC current according to the formula: I = K * (Bz1 - Bz2), where K is a predetermined constant independent of the waveform and spectrum of the AC current. The value of K can be determined in a known manner, such as through simulation, calibration, or other suitable methods, and the value of K can be stored in the non-volatile memory 931, 1031 of the current sensor device.

[0128] The surprising effect lies not in the formula itself, nor in the gradient measurement results, but in the accuracy achieved by the formula through the presence of the metal plate 103, despite the skin effect, even at frequencies up to 2000 Hz. To understand this improvement, note that without the metal plate, the error in AC current measurement results can be approximately 10%. Thanks to this invention, this error can be reduced to approximately + / -5%, or within + / -4%, or within + / -3%, or within + / -2%, as will be shown in Figures 2 and 3.

[0129] Preferably, the magnetic sensor elements H1 and H2 are located approximately midway between the top and bottom surfaces of the electrical conductor portions 101a and 101b in the height direction (Z), although this is not absolutely necessary. And preferably, the two sensor elements H1 and H2 are symmetrically located between the two electrical conductor portions 101a and 101b in the X direction, although this is also not absolutely necessary (as will become clear when discussing Figure 2(b)).

[0130] It was also found that the dimensions of the current sensor system 100 (e.g., the length Lp and width Wp of the metal plate 103) were not critical for improvement, nor was the accurate positioning of the current sensor device 102. That is, the accuracy of the measurement results can vary primarily based on the distance “g” between the metal plate 103 and the busbar 101 and / or based on the thickness Tp or conductivity of the conductive surface. As a rule of thumb, it can be understood that the accuracy of AC current measurements increases as the distance “g” between the metal plate 103 and the conductive portions 101a, 101b decreases, and increases as the thickness Tp of the metal plate increases.

[0131] As an example, the electrical conductor (e.g., busbar) 101 may have a total width Wc of approximately 3 mm to approximately 15 mm, and a thickness Tc of approximately 2.0 mm to approximately 5.0 mm. The thickness Tp of the metal plate 103 may be a value in the range of approximately 0.5 mm to 10 mm or 0.5 mm to 5.0 mm. The distance between the conductive surface 103 and the magnetic sensitive elements H1, H2 may be a value in the range of 0.5 mm to 10 cm or 0.5 mm to 5 cm. The length Lp and width Wp of the plate 103 are preferably at least Wc*50%, or at least 75%*Wc, or at least Wc, but larger values ​​may also be used, such as Wc*50% to Wc*200%. In the examples of Figures 1(c) and 1(d), the metal plate 103 is substantially square, and Lp = Wp = approximately 125% of the conductor width Wc. The length Lp may be equal to the width Wp, but this is not required.

[0132] In a variant (not shown) of the current sensor system 100 in Figure 1(c), the magnetic sensor device 102 is rotated 90° about the X-axis such that the semiconductor substrate of the magnetic sensor device is perpendicular to the metal plate 103 and perpendicular to the longitudinal direction Y of the electrical conductor 101, and the sensor device includes, for example, two vertical Hall elements or two magnetoresistive elements for measuring the magnetic field value oriented in the Z direction.

[0133] In description Figures 1(a) to 1(d) Before referring to the simulation results of the current sensor system 100, we will refer to Figures 1(e) to 1(f) To describe another variant of the current sensor system 100. Figures 1(a) to 1(d) The current sensor system 100 and Figures 1(e) to 1(f) The most important difference between the current sensor systems 150 is the orientation of the magnetic sensor device 152. As can be seen in Figure 1(e), the substrate of the magnetic sensor device 152 is oriented perpendicular to the metal plate 103 and parallel to the longitudinal axis Y of the electrical conductor 101.

[0134] Referring to Figure 1(f), the magnetic sensor device 152 can be configured to measure a first magnetic field component Bx1 oriented in the lateral direction X of an electrical conductor (e.g., a busbar) using a first horizontal Hall element H3, and to measure a second magnetic field component Bx2 using a second horizontal Hall element H4 spaced apart from the first horizontal Hall element H3 by a distance dz. The magnetic sensor device 152 can also be configured to determine the difference ΔBx between these two values, for example, according to the formula: ΔBx = Bx1 - Bx2, and can be configured to determine the magnitude of the AC current according to the formula: I = K2 * (Bx1 - Bx2), where K2 is a predetermined constant independent of the waveform of the AC current and substantially independent of the specific spectrum of the AC current (assuming the AC current has a spectral peak, lobe, or spectral component below or up to 2000 Hz). The value of K2 can be determined in a known manner, such as through simulation, calibration, or other suitable means, and the value of K2 can be stored in the non-volatile memory 931, 1031 of the current sensor device. The advantage of this embodiment is that the semiconductor substrate of the sensor device 152 can be oriented parallel to the YZ plane, because this only requires a “relatively narrow slit” between the two conductor portions 101a and 101b, i.e., a relatively small value for the distance Ws between the two conductor portions.

[0135] In a variant of the current sensor system 150 (not shown), the sensor device is rotated more than 90° around the Z-axis such that the semiconductor surface is parallel to the XZ plane, and the semiconductor device includes two vertical Hall elements or two magnetoresistive elements configured to measure the values ​​of Bx1 and Bx2 oriented in the X direction, similar to Figure 1(f).

[0136] The dimensions of the metal plate 103 are not critical to the effectiveness of this invention. In one embodiment, the width Wp of the metal plate is less than the outer width Wc of the two electrical conductor portions. In another embodiment, the width Wp of the metal plate is substantially equal to the outer width Wc of the two electrical conductor portions. In yet another embodiment, the width Wp of the metal plate is greater than the width Wc of the two electrical conductor portions, for example, at least 20% or at least 50% greater.

[0137] Although not shown, in Figures 1(a) to 1(f)In all embodiments, and particularly in the embodiments of Figures 1(e) and 1(f), the current sensor system 150 may optionally include a second metal plate parallel to the first metal plate, arranged on opposite sides of the busbar 101 such that two conductive portions 101a, 101b are located between the two metal plates. In this embodiment, the sensor elements H3, H4 are equidistant from the metal plates, which can further improve accuracy.

[0138] Figure 2(a) shows the simulation results of the amplitude and phase of the magnetic field component Bz, which is a function of the X-axis and induced by a sinusoidal AC current of various frequencies, as a complex representation, and can be measured at various positions along the X-axis. The vertical lines indicate the values ​​measured by the sensor elements H1 and H2 of the sensor device 102 of Figure 1(d) in the absence of the metal plate 103. The simulation was performed for a sensor system with the following parameters: (busbar:) Wc = 18 mm, Tc = 3 mm, Ws = 9 mm; (metal plate:) Tp = 5 mm, Lp = Wp = 5 cm to 10 cm, g = 75 mm; however, the invention is of course not limited to these, and other dimensions can be used.

[0139] As shown in the figure, the real parts of Bz1 and Bz2 are frequency-dependent: the curve with squares (corresponding to a 100Hz current) does not coincide with the curve with triangles (corresponding to a 1000Hz signal), and it does not coincide with the curve with circles (corresponding to a 2000Hz signal). Furthermore, the difference between the real parts of Bz1 and Bz2 is also frequency-dependent, because the difference between the two curves with circles is different from the difference between the two curves with squares. Similarly, the imaginary parts of Bz1 and Bz2 are frequency-dependent, and the difference between their imaginary parts is also frequency-dependent.

[0140] Figure 2(b) shows the simulation results in the presence of the metal plate 103. As can be seen, the individual signals Bz1 and Bz2 still depend on their respective frequencies, but the difference between the real parts of Bz1 and Bz2 is essentially independent of the frequency. This difference depends only on the magnitude of the AC current.

[0141] As can be further seen, although the imaginary parts of individual components vary with frequency, the imaginary parts of Bz1 and Bz2 are essentially equal, therefore the difference between them is essentially zero and independent of frequency. In other words, the phase shift between Bz1 and Bz2 is zero. Thus, according to the formula I = K*(Bz1 - Bz2), the magnitude of ΔBz = (Bz1 - Bz2) is proportional to the magnitude of the AC current, where K is a constant that is independent of the frequency composition of the current waveform for frequencies ranging from DC to approximately 2000 Hz. To the inventor's knowledge, this teaching is unknown in the prior art.

[0142] As can also be understood from Figure 2(b), the positions of the two Hall sensor elements x1 and x2 are not critical at all, the distance "dx" between the two Hall sensor elements is not critical at all, and the position of the sensor device 102 within the gap (along the X-axis) between the two conductor portions 101a and 101b is not critical at all.

[0143] Those skilled in the art who benefit from this disclosure can easily find the optimal position of the sensor 102 for a given busbar (Wc, Tc, Ws) and a given metal plate (Lp, Wp, Tp) and a given distance (g) between them by moving the sensor device 102 closer to or away from the metal plate, performing a set of measurements on AC currents of various frequencies, and selecting the position that produces the most accurate results (this paragraph is also referred to herein as the “first optimization method”).

[0144] Alternatively, for a given location of the sensor device, a technician can find the optimal distance “g” between the busbar and the metal plate (also referred to herein as the “second optimization method”) by moving the metal plate 103 closer to or further away from the sensor device (and the busbar), by performing a set of measurements on AC currents of various frequencies, and by selecting the location that produces the most accurate results.

[0145] For a given busbar and a given metal plate, the overall optimal arrangement can be found, for example, by starting from the initial position of the sensor device 102 (e.g., at the midpoint between the two electrical conductor portions and at half their height Tc / 2) and the initial distance “g” (e.g., approximately 75 mm) between the busbar and the metal plate, and by alternately repeating the methods described in the first two paragraphs until the desired accuracy is found. If the result is unsatisfactory, the process can be repeated or another busbar and / or another metal plate can be used (this paragraph is also referred to herein as the “overall optimization method”).

[0146] Figure 3(a) shows the process without the metal plate 103, by Figures 1(a) to 1(d) The sensor element measures how the signal will attenuate and phase shift as a function of frequency. The top graph shows the amplitude of the individual signal (approximately 3 mT in this example) and the amplitude of the differential signal (approximately 6 mT in this example). The middle graph shows the attenuation as a percentage, and the bottom graph shows the phase shift relative to an AC current with a frequency of 100 Hz in degrees. As can be seen, in this particular example, the magnetic field caused by an AC current with a frequency of 2000 Hz will attenuate by approximately 3.7%, and the phase shift will be approximately -2° relative to an AC current with the same amplitude but a frequency of 100 Hz. In other examples (not shown), the attenuation could be approximately 6% and the phase shift could be approximately 3°.

[0147] Figure 3(b) shows the situation in the presence of metal plate 103, where... Figures 1(a) to 1(d) The sensor elements measure how individual signals will attenuate and phase shift as a function of frequency, and show the differences between these signals.

[0148] As shown in the figure, the differential signal or gradient signal (indicated by squares) has a constant amplitude (see the horizontal line with squares in the central figure) and zero phase shift (see the horizontal line with squares in the lower figure), which is independent of the frequency of the AC current.

[0149] Surprisingly, the negative effects of the skin effect can be completely eliminated by adding a metal plate or another conductive surface near the busbar, measuring the magnetic field components at two locations x1 and x2 spaced apart by a distance dx within the gap between the two conductor sections 101a and 101b, and calculating the magnetic field difference or spatial gradient. This current sensor device 102 can determine the instantaneous magnitude of an AC current with one or more frequencies up to 2000 Hz by simply measuring the gradient and multiplying it by a predefined constant “K”, without requiring frequency analysis (e.g., Fourier analysis) or time-domain analysis to determine the waveform shape.

[0150] When the above-described "first, second, and overall optimization methods" are combined with the simulation results of Figures 2 and 3, those skilled in the art will now understand that they only need to compare the measurement results of a 100Hz sinusoidal current with a 2000Hz sinusoidal current of the same amplitude, and if these results are substantially the same, then the results for intermediate frequencies will also be the same. This can significantly simplify the (multiple) methods for finding suitable, semi-optimal, or optimal positions.

[0151] Figures 4(a) to 4(h) A second embodiment and variations thereof of a current sensor system according to the present invention are shown, wherein the current sensor system comprises:

[0152] - Electrical conductor 401 (e.g., busbar), which extends primarily in the first direction Y and has two transverse cuts 411, 412 (extending in the X direction from opposite sides S1, S2 of the busbar), these cuts are spaced apart from each other in the longitudinal direction Y so as to form a zigzag shape with transverse channel regions 406 between the two cuts (see, for example, FIG4(e)).

[0153] -Magnetic sensor device 402 arranged near the channel area;

[0154] - A metal plate 403 having an opening 413, the metal plate being arranged near the channel area at a distance "g" from the busbar in the Z direction.

[0155] Instead of a metal plate with an opening, an object with a surface or layer, a portion of which is non-conductive, may be used, the non-conductive surface or layer portion being surrounded by a conductive surface or layer portion.

[0156] exist Figures 4(c) to 4(e) In this embodiment, sensor device 402 has a semiconductor substrate oriented parallel to the XY plane of electrical conductor 401 (perpendicular to the thickness direction Z of electrical conductor) and parallel to metal plate 403. The height position (in the Z direction) of sensor device 402 can vary between a position near the busbar (see, for example, FIG. 4(c)) to a position near the metal plate (see, for example, FIG. 4(e)) or even beyond the metal plate (see FIG. 4(d)). Sensor device 402 may include two horizontal Hall elements H1, H2, each configured to measure magnetic field components oriented in the Z direction, referred to herein as Bz1 and Bz2, respectively.

[0157] Figure 4(b) illustrates how eddy currents will flow in a plate (shown in a cover layer above the busbars) having an opening 413 "above" in the channel area or zigzag center. In the example of Figure 4(b), the width Wp of the plate is substantially equal to the width Wc of the electrical conductor, but this is not absolutely necessary for the invention to be effective. As described above with respect to the first embodiment, the shape and size of the metal plate are also not critical in the second embodiment. Preferably, the width Wp of the plate (measured in the transverse direction X) is in the range of about 50% to about 300% of the width Wc of the electrical conductor, or in the range of about 50% to about 200% of Wc, for example, about 100% or about 150% of Wc.

[0158] In the example of Figure 4(b), the length Lp of the metal plate (measured in the Y direction) extends beyond the locations of the two cuts or slits 411, 412, but this length Lp is not critical as long as the length Lp of the metal plate 401 is long enough, for example, at least equal to or longer than the length L2 between the distal edges of the cuts 411, 412.

[0159] Figure 4(a) is a schematic cross-sectional view of Figure 4(b) in plane AA. The four sensor positions are indicated (each sensor position is indicated by a black dot), but it is sufficient to measure, for example, only Bz1 and Bz2 "above the plate" or only Bz3 and Bz4 "below the plate", or to measure the two magnetic field components "located at the same height as the plate" (e.g., as shown in Figure 4(e)).

[0160] In all these cases, the magnitude of the AC current can be determined according to the formula: I = K1 * (dBz / dy), or if the values ​​of dy and K1 are combined, the magnitude of the AC current can be determined according to the formula: I = K * ΔBz = K * (Bz1 - Bz2) or I = K * (Bz3 - Bz4).

[0161] The value of K is constant and independent of frequency. The value of K can be determined in a known way, such as during offline testing or calibration testing, and can be stored in the non-volatile memory 931, 1031 of the sensor device.

[0162] In the variant shown in Figure 4(f), the sensor system 480 includes two sensor devices 402a and 402b mounted on opposite sides of a substrate (e.g., printed circuit board 485). The first sensor device 402a is configured to measure Bz1 and Bz2 at a first height position (e.g., above metal plate 403) and determine a first current value I1. The second sensor device 402b is configured to measure Bz3 and Bz4 at a second height position (e.g., at or below plate 403) and determine a second current value I2. For redundancy or functional safety purposes, the two current values ​​I1 and I2 can be compared, for example, by one of the sensor devices or by an external processing unit (e.g., ECU). If the two values ​​I1 and I2 are more or less the same within a predefined tolerance margin, the two current values ​​can also be averaged, which further improves accuracy. If the deviation between the two current values ​​exceeds the predefined tolerance margin, this is an indication of a fault condition.

[0163] In another variant (not shown), the current sensor system includes a single sensor device having two semiconductor dies stacked one on top of the other. The first die is configured to measure Bz1 and Bz2 at a first distance from the busbar, and the second die is configured to measure Bz3 and Bz4 at a second distance from the busbar. The semiconductor dies may have the same size, but do not need to have the same size. In a particular embodiment, the lower die may have two horizontal Hall elements H3, H4 spaced apart by a distance dy1, and the upper die may have two horizontal Hall elements H1, H2 spaced apart by a distance dy2 less than dy1. The first and second dies are interconnected via bonding wires connected to pads located on the upper surfaces of the two dies.

[0164] In the example of Figure 4(g), the sensor system 460 includes two sensor devices 402a and 402b, which are spaced apart along the Y-axis and oriented such that their semiconductor substrates are perpendicular to the Y-axis of the busbar and therefore also perpendicular to the metal plate 403. The first sensor device 402a may include two vertical Hall elements V1 and V3 for measuring Bz1 and Bz3, one of which may be located above the metal plate 403, while the other may be located at the same height as or below the metal plate. Similarly, the second sensor device 402b may include two vertical Hall elements V2 and V4 for measuring Bz2 and Bz4, one of which may be located above the metal plate 403, while the other may be located at the same height as or below the metal plate. For redundancy purposes, a subsequent processing unit (e.g., a processing unit of one of the sensor devices in the sensor array, or an external processing unit (e.g., an ECU)) can calculate the first current I1 based on Bz1 and Bz2, and the second current I2, for example, based on Bz3 and Bz4. The two sensor devices 402a and 402b can be mounted on opposite sides of a printed circuit board (PCB) 465, as shown in Figure 4(h).

[0165] In the variant of Figure 4(g), each sensor device contains only one sensor element; for example, sensor device 402a contains only a vertical Hall element V1, and sensor device 402b contains only a vertical Hall element V2. The same formula can be used to calculate the AC current, but of course, there is no redundancy in this case.

[0166] A specific example of the current sensor system shown in Figure 4(e) is simulated, which has the following parameters: (busbar:) Wc = 18 mm, Tc = 3 mm, L1 = 6 mm, L2 = 16 mm, square opening = 2 mm × 2 mm; (metal plate:) Wp = 40 mm, Lp = 40 mm, Tp = 105 μm, g = 0.5 mm. However, the present invention is of course not limited to systems with these specific dimensions.

[0167] Figure 5(a) shows the simulation results of the real and imaginary parts of the magnetic field component Bz induced by the sinusoidal AC current at different frequencies and positions along the Y-axis, as measured by the sensor element of the sensor device of Figure 4(e) in the absence of the metal plate 403.

[0168] These charts are similar to those in Figure 2, targeting locations near the "channel area" and the opening in metal plate 403. The vertical lines in Figure 5(a) indicate locations 2.0 mm apart in the example. Figure 4c to Figure 4eThe position or indication of sensor elements H1 and H2 Figure 4g The positions of sensor elements V1 and V2.

[0169] As shown in the figure, the real parts of Bz1 and Bz2 are slightly frequency-dependent: the curve with squares (corresponding to a 100Hz current) does not coincide with the curve with circles (corresponding to a 2000Hz signal). Therefore, the difference between the real parts of Bz1 and Bz2 is also frequency-dependent. However, it can also be seen that the imaginary parts of Bz1 and Bz2 are even more frequency-dependent, so the difference between their imaginary parts is also frequency-dependent. If the magnitude of the current is calculated based on these component values ​​or the differences or gradients between these component values, the measurement results will be inaccurate.

[0170] Figure 5(b) shows the simulation results in the presence of a metal plate 403 with an opening 413. As can be seen, because the curves essentially coincide at the measurement location, the real and imaginary parts of the individual signals Bz1 and Bz2 depend not on the frequency, but only on the magnitude of the AC current. Therefore, the difference between the real parts of Bz1 and Bz2 is also essentially independent of the frequency. Furthermore, the imaginary parts of Bz1 and Bz2 are essentially zero and independent of the frequency. Therefore, the phase shift between Bz1 and Bz2 is also zero. Thus, according to the formula I = K * (Bz1 - Bz2), the magnitude of ΔBz = (Bz1 - Bz2) is proportional to the magnitude of the AC current, where K is a constant that is independent of the frequency composition of the current waveform for frequencies in the range from DC to approximately 2000 Hz. To the inventor's knowledge, this behavior is unknown in the prior art.

[0171] It should also be understood from Figure 5(b) that the positions of the two Hall sensors, x1 and x2, are not critical and can be slightly offset, and the distance "dx" between the two Hall sensors is also not critical. Preferably, the opening 413 has a square or rectangular shape, with a length and width of about 90% to about 150% of the distance dx between the sensor elements, but other shapes may also be effective, such as circular, elliptical, hexagonal, octagonal, polygonal, etc.

[0172] Since the imaginary parts of Bz1 and Bz2 are equal to zero, the current can also be calculated using the following formulas: I = K * Bz1 or I = K * Bz2. This embodiment requires only a single sensor device with a single magnetic sensor element. However, such a current sensor system is not robust to external disturbance fields (fremdfeld), while a current sensor system that determines the current based on the magnetic field difference or gradient is essentially "spurious field immune."

[0173] Figures 6(a) to 6(g)A third embodiment of a current sensor system 600 according to the present invention is shown, wherein the current sensor system includes: an elongated electrical conductor 601 (e.g., a busbar) having two transverse cuts spaced apart from each other in the longitudinal direction (Y) to form a zigzag shape with transverse channel regions; a magnetic sensor device 602 disposed near said channel regions; and a metal plate 603 having edges asymmetrically disposed near the channel regions (e.g., straight edges oriented in the transverse direction X of the busbar), and preferably extending over the entire width Wc of the electrical conductor 601. This embodiment can be considered a variation of the embodiment of FIG. 4, the main difference being that the metal plate 603 or an object with a conductive surface in FIG. 6 is located on only one side of the “channel region” instead of on both sides of the “channel region” as in the case of FIG. 4. Much of what has been described above with respect to the second embodiment and its variations (FIG. 4) also applies to the third embodiment (FIG. 6), unless otherwise explicitly mentioned or the context clearly indicates otherwise.

[0174] Figure 6(b) shows a top view of conductor 101. Conductor 601 may be the same as conductor 401 shown in Figure 4.

[0175] Figure 6(a) shows the cross section of Figure 6(b) according to AA.

[0176] Figures 6(e) to 6(g) A perspective view is shown, with Figures 4(c) to 4(e) Similarly, but using metal plates positioned asymmetrically or eccentrically relative to the "lateral passage area".

[0177] Figure 6(c) shows an example of a rectangular metal plate that can be used in this embodiment. The width Wp of the plate is preferably equal to the width Wc of the electrical conductor (e.g., busbar), but this is not absolutely necessary, and Wp can also be greater than the conductor's width Wc, or even slightly smaller. For example, Wp can be 50% to 300% of Wc. This value is not critical. The length Lp of the plate (in the longitudinal direction Y of the busbar) is also not critical. Preferably, the length Lp is sufficiently long, for example, at least as long as the length L1 between the proximal edges of the slits or cuts 611, 612, or at least the length L2 between the distal edges of the slits or cuts 611, 612, or at least 150% of L2, or at least 200% of L2. The value of this length is not critical for the effectiveness of the invention.

[0178] Figure 6(d) illustrates the possible dimensions of such a current sensor system. In the example, the busbar 601 has a width Wc = 20 mm, a notch or slit width (in the Y direction) of 3.5 mm and a length of approximately 12 mm, a distance L1 of 6 mm, a distance L2 of 13 mm, a plate length (in the Y direction) of 19 mm (equal to approximately L2 * 150% in this example), and a plate width of 40 mm (equal to Wp * 2 in this example). However, this is, of course, only an example, and the present invention does not require these specific dimensions. Figure 6(d) also illustrates an example of eddies flowing in such a plate.

[0179] Figure 7 shows the simulation results of the current sensor system in Figure 6. The two vertical lines at y1 = -1 mm and y2 = +1 mm indicate the positions of the two Hall elements H1 and H2 along the Y-axis.

[0180] Figure 7(a) shows the real parts (in arbitrary units) of the magnetic field components Bz1 and Bz2 as a function of the position along the central axis Y of the busbar and above the central axis Y of the busbar for AC currents of various frequencies in the range of 100Hz to 2000Hz. As can be seen from the figure, each real part depends on the frequency, but the real part of the differential signal ΔBz = (Bz1 - Bz2) or the real part of the gradient (ΔBz / dy) does not depend on the frequency.

[0181] Figure 7(b) shows the imaginary parts of the magnetic field component signals Bz1 and Bz2. As can be seen, each imaginary part depends on the frequency, but the imaginary part of the differential signal ΔBz = (Bz1 - Bz2) or the imaginary part of the gradient (ΔBz / dy) does not depend on the frequency or depends only slightly on the frequency. This result is highly counterintuitive due to the asymmetry. To the inventors' knowledge, the prior art does not teach that placing a metal plate near the busbar, and in an asymmetric position, will improve the accuracy of AC current measurements by essentially compensating for the skin effect.

[0182] Figures 8(a) to 8(c) A fourth embodiment of the current sensor system according to the present invention is shown, wherein the current sensor system 800 includes: an elongated electrical conductor 801 (e.g., a busbar) having a U-shaped shield 840; a conductive plate 803 disposed at a distance "g" from the busbar 801; and a magnetic sensor device 802 (not shown), the magnetic sensor device being disposed within a space defined or bounded by the metal plate 803 and the shield 840. As shown, the metal plate 803 does not have an opening. The metal plate may be part of a shield in the form of a metal box surrounding the busbar.

[0183] Figure 8(a) shows a cross-section of the current sensor system 800 in a plane α perpendicular to the longitudinal direction Y of the busbar. The sensor device 802 is preferably positioned substantially above the middle of the busbar 801 in the lateral direction X. The height position “h” is not critical, but is preferably substantially midway between the top surface of the busbar 801 and the bottom surface of the metal plate 803, or the distance h from the busbar 801 can also be a value in the range of approximately 30% to approximately 70% of the distance “g” between the busbar 801 and the metal plate 803.

[0184] Figure 8(b) shows a perspective view.

[0185] Figure 8(c) is a schematic representation of a magnetic sensor device 802 having a single vertical Hall sensor (schematically represented by the black line) configured to measure a magnetic field component Bx oriented in the transverse direction of the electrical conductor 802 and in the X direction parallel to the metal plate 803.

[0186] The sensor device 802 is configured to determine the current I according to the formula: I = K * Bx, where Bx is the magnetic field component and K is a constant independent of frequency.

[0187] In a variant of this embodiment, the sensor device is located on the opposite side of the metal plate, that is, above the metal plate in Figures 8(a) and 8(b).

[0188] This also achieves the same advantages as described above (improved accuracy of AC current measurements). Due to the shielding, this embodiment is also robust to external interference fields.

[0189] Although current sensor devices using one or more magnetic sensitive elements are known in the art, this is provided for completeness. Figure 9 and Figure 10 .

[0190] Figure 9 An electrical block diagram of a circuit 910 that can be used in the current sensor device of the above embodiments is shown. This block diagram does not include a temperature sensor or a stress sensor.

[0191] Processing unit 930 is adapted to determine the current to be measured by calculating the current according to the formula: I = K * v1 or I = K * (v1 - v2), where K is a predefined constant, which can be determined by simulation during design or during the evaluation or calibration phase, v1 is a value provided by a first magnetic sensor 911 (or a value derived therefrom, for example, after amplification), and v2 (if present) is a value provided by a second magnetic sensor 921 (or a value derived therefrom). The subtraction can be performed in hardware before or after amplification, or it can be performed in the digital domain. Processing unit 930 may include a digital processor that includes or is connected to a non-volatile memory 931 storing the at least one constant value K.

[0192] The processing circuitry 910 may include a differential amplifier configured to determine and amplify the difference between a first value v1 and a second value v2, and to amplify the difference in the analog domain. Alternatively, the processing circuitry 910 may include an amplifier configured to selectively amplify the first value v1 and the second value v2. The sensor device may further include an analog-to-digital converter (ADC) configured to digitize these amplified signals. The ADC may be part of a digital processor circuit.

[0193] The current to be measured can be provided as an analog output signal proportional to the current, or it can be provided, for example, via a digital data interface (e.g., via a serial data bus (e.g., using the I2C protocol, or the RS232 protocol, or any other suitable protocol)) as a digital signal indicating the current to be measured.

[0194] Figure 10 An electrical block diagram of the processing circuit 1010 is shown, which can be considered as... Figure 9 A variant of the processing circuitry 910 further includes a first temperature sensor 1012 and / or a second temperature sensor 1022 communicatively connected to the processing unit 1030. The processing unit 1030 is adapted to determine the current to be measured based on one or both of values ​​v1 and v2, further taking into account one or both of temperature signals t1 and t2. The measured temperatures(s) can be considered to compensate for temperature variations in the measured values ​​v1 and v2, for example, to compensate for sensitivity variations in the sensor elements. Such compensation techniques are known in the art and therefore do not require detailed explanation here.

[0195] In certain embodiments, temperature compensation is performed in a manner similar to that described in EP3109658(A1), which is incorporated herein by reference in its entirety.

[0196] The advantage of current sensors lies in their inclusion of a temperature compensation mechanism. This allows for further improvement in the accuracy of current measurement results.

[0197] Figure 9 Processing unit 930 and Figure 10 The processing unit 1030 may include a digital processor, such as a programmable microcontroller. Although not explicitly shown, circuits 910 and 1010 may also include at least one analog-to-digital converter, which may be part of the magnetic sensor, part of the processing unit, or may be implemented as a separate circuit (e.g., between the output of the sensor circuit and the input of the processing unit). For the same reasons as bias circuits, readout circuits, optional amplifiers, power supplies, etc., which are known in the art and therefore do not need to be described in detail herein, Figure 9 and Figure 10 The block diagram does not show this level of detail.

[0198] It should be noted in this regard that if signals v1, v2, t1 and t2 are analog signals, then processing unit 1030 may include at least one ADC for converting these signals into digital signals, while if signals v1, v2, t1 and t2 are digital signals, processing unit 1030 does not need to have an ADC.

[0199] The advantage of an embodiment with two temperature sensors is that each magnetic sensor has its own temperature sensor, because the temperatures of the first and second magnetic sensors can be significantly different, especially when measuring relatively high currents in the vicinity of the busbar, as such high currents typically cause the busbar to heat up significantly, resulting in a relatively large temperature gradient on the substrate of the sensor device. In this way, the accuracy of current measurement can be further improved.

[0200] exist Figure 10 In a variant (not shown), the circuit includes only one temperature sensor, which can be arranged to measure the temperature of the first magnetic sensor or the temperature of the second magnetic sensor. The temperature of the other magnetic sensor can then be estimated based on estimated power consumption (and thus based on v1 and v2) and / or on predefined assumptions about ambient temperature, rather than actually measuring the other temperature. Of course, embodiments with two temperature sensors are more accurate.

[0201] exist Figure 10 In a variant (not shown), the circuit includes one or two mechanical stress sensors instead of one or two temperature sensors, and the processing unit 1030 is adapted to determine the current based on the value obtained from the magnetic sensor and taking into account the stress values(s) obtained from one or two stress sensors.

[0202] exist Figure 10In another variant (not shown), the circuit additionally includes one or two stress sensors in addition to one or two temperature sensors, and the processing unit 1030 is adapted to determine the current based on values ​​obtained from the magnetic sensor and one or more temperature sensors and one or more stress sensors.

[0203] In the embodiments, each magnetic sensor element H1, H2 has an associated temperature sensor and an associated mechanical stress sensor, and the processing circuit is configured to measure two magnetic signals, and to measure two temperatures, and to measure two mechanical stress values, and is configured to determine ΔBz = Bz1 - Bz2, and to multiply the value ΔBz by a predefined constant factor K (independent of frequency), and to compensate for the results of temperature and / or mechanical stress, for example, using a polynomial expression of temperature and / or stress, as described in EP3109658(A1), which is incorporated herein by reference in its entirety.

[0204] exist Figures 1(a) to 6(g) In the embodiments described, preferably there is no shielding around the busbar, or in other words, preferably these current sensor systems are "coreless". As mentioned above, the current sensor systems of Figures 8(a) and 8(b) may have shielding.

[0205] The attached diagram shows only one busbar, and in Figures 1(a) to 1(f) The busbar can be divided into two parallel parts that conduct in-phase current, but of course the invention is not limited to this and can also be used in three-phase systems.

[0206] The present invention also relates to a current sensor system comprising three electrical conductors and three magnetic sensor devices. The three electrical conductors may be arranged substantially in parallel. The three-phase current sensor system may comprise three separate metal plates, each arranged as follows: Figures 1(a) to 8(b) The arrangement shown is similar to the corresponding busbars, and the width Wp of each metal plate in the lateral direction of the busbar is less than the distance between the centers of adjacent busbars, for example, the width Wp is in the range of 0.50 to 0.95 times said distance. Alternatively, the three-phase current system may include a single printed circuit board (PCB) having at least three current-separated conductive areas. The PCB may be a multilayer PCB.

Claims

1. A current sensor system for measuring an AC current having a frequency in a predefined frequency range, the system comprising: - an electrical conductor configured for conducting the AC current, thereby creating a first magnetic field; - a magnetic sensor device; - a metal plate or an electrically conductive surface arranged in the vicinity of the electrical conductor for allowing eddy currents to flow in the surface, thereby creating a second magnetic field, the second magnetic field superimposing the first magnetic field; characterized in that the magnetic sensor device is configured for measuring a first magnetic field component at a first sensor position and for measuring a second magnetic field component at a second sensor position spaced apart from the first sensor position, and for determining a magnetic field difference or a magnetic field gradient based on a difference between the first magnetic field component and the second magnetic field component; - the magnetic sensor device is configured to determine the magnitude of the AC current according to the formula I = K (ΔBz) or I = K (ΔBx), wherein I is the magnitude of the AC current to be measured, K is a predefined constant independent of the frequency, and ΔBx or ΔBz is a magnetic field difference or a magnetic field gradient.

2. The current sensor system of claim 1, wherein the sensor device is arranged at a position where a superposition of the first magnetic field and the second magnetic field has a substantially constant size in a frequency range comprising a range from 100 Hz to 2 kHz.

3. The current sensor system of claim 1, wherein the magnetic sensor device is an integrated semiconductor device, and wherein the electrical conductor is arranged outside the integrated semiconductor device.

4. The current sensor system of claim 1, wherein the electrically conductive surface is a metal sheet or a metal layer.

5. The current sensor system of claim 1, wherein the electrical conductor comprises a first and a second beam-like conductor portion, both extending in a longitudinal direction and spaced apart from each other to form a gap therebetween; and wherein the metal plate or the electrically conductive surface is arranged parallel to the electrical conductor and at a predefined distance from the electrical conductor to form a gap or a slit therebetween; and wherein the magnetic sensor device is arranged within the gap or the slit.

6. The current sensor system of claim 1, wherein the magnetic sensor device is configured for measuring the first magnetic field component and the second magnetic field component, both oriented in a height direction of the electrical conductor; and wherein the first sensor position and the second sensor position are spaced apart in a lateral direction.

7. The current sensor system of claim 1, wherein the magnetic sensor device is configured for measuring the first magnetic field component and the second magnetic field component, the first magnetic field component and the second magnetic field component being oriented in a lateral direction of the electrical conductor; and wherein the first sensor position and the second sensor position are spaced apart in a height direction of the electrical conductor.

8. The current sensor system of claim 1, wherein the electrical conductor has an elongated shape extending in a first direction and has a width extending in a lateral direction perpendicular to the first direction; and wherein the electrical conductor comprises a first cut-out extending from a first side of the electrical conductor over at least half of the width and a second cut-out extending from a second side of the electrical conductor over at least half of the width, the first cut-out and the second cut-out defining a lateral passage region therebetween; and wherein the metal plate or the electrically conductive surface has an opening or a non-conductive region located in the vicinity of the lateral passage region; and wherein the metal plate or the electrically conductive surface is located at a first distance from the electrical conductor; and wherein the magnetic sensor device is arranged in the vicinity of the opening or the non-conductive region at a second distance from the electrical conductor that is smaller than the first distance, or at a second distance that is larger than the first distance, or at a second distance that is equal to the first distance.

9. The current sensor system of claim 8, wherein the magnetic sensor device is configured for measuring the first magnetic field component and the second magnetic field component, the first magnetic field component and the second magnetic field component being oriented in a height direction of the electrical conductor; and wherein the first sensor position and the second sensor position are spaced apart in a longitudinal direction of the electrical conductor.

10. The current sensor system of claim 8 or 9, wherein the magnetic sensor device is mounted to a first side of a printed circuit board and comprises a first magnetic sensor for measuring the first magnetic field component and a second magnetic sensor for measuring the second magnetic field component; and wherein the current sensor system further comprises a second magnetic sensor device mounted to a second side of the printed circuit board opposite the first side, the second magnetic sensor device comprising a third magnetic sensor and a fourth magnetic sensor configured for measuring a third magnetic field component and a fourth magnetic field component, the second magnetic sensor being configured for determining a second magnetic field difference or a second magnetic field gradient.

11. The current sensor system of claim 10, wherein the printed circuit board is parallel to a plane defined by the first direction and a lateral direction; or wherein the printed circuit board is oriented perpendicular to the first direction.

12. The current sensor system of claim 8 or 9, wherein the magnetic sensor device comprises two semiconductor dies stacked on top of each other, the two semiconductor dies comprising: - a first semiconductor die configured for measuring the first magnetic field component and the second magnetic field component at a first distance from the electrical conductor; and - a second semiconductor die configured for measuring a third magnetic field component and a fourth magnetic field component at a second distance from the electrical conductor.

13. The current sensor system of any one of claims 1 to 4, wherein the electrical conductor has an elongated shape extending in a first direction and a width extending in a lateral direction perpendicular to the first direction; and wherein the electrical conductor comprises a first cut-out extending from a first side of the electrical conductor over at least half of the width and a second cut-out extending from a second side of the electrical conductor over at least half of the width, the first cut-out and the second cut-out defining a lateral passage area therebetween; and wherein the metal plate or the electrically conductive surface is parallel to the electrical conductor and is located on only one side of an imaginary plane oriented perpendicular to the first direction and in between the first cut-out and the second cut-out; and wherein the metal plate or the electrically conductive surface is located at a first distance from the electrical conductor; and wherein the magnetic sensor device is arranged in proximity of the lateral passage area at a second distance from the electrical conductor smaller than the first distance, or at a second distance larger than the first distance, or at a second distance equal to the first distance.

14. The current sensor system of claim 13, wherein the magnetic sensor device is configured to measure the first magnetic field component at a first sensor position and the second magnetic field component at a second sensor position, the first and second magnetic field components being oriented in a height direction of the electrical conductor; and wherein the first and second sensor positions are spaced apart in a longitudinal direction.

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