Current sensor

Abstract

The invention relates to a current sensor. A current sensor is provided that includes a plurality of substrates stacked such that each substrate rotates relative to adjacent substrates of the plurality of substrates. Each substrate includes a path of a conductor for carrying a current measured by a current sensor. Each substrate includes a plurality of measurement coils advancing around a conductor path.

Description

Technical Field

[0001] The present invention relates to a current sensor, and in particular to a current sensor comprising a plurality of substrates. Background Art

[0002] Current sensors detect and measure the current flowing through a conductor. They are used in many different applications, for example, providing accurate current measurement in utility meters.

[0003] One type of current sensor uses a shunt resistor connected in series with the current-carrying conductor. The voltage drop across the resistor can be measured, and by knowing the resistance of the shunt, the current through the resistor can be calculated. However, at higher currents, the shunt's temperature may increase, changing its resistance and providing an inaccurate current measurement. Furthermore, because the shunt is directly in the path of the measured current, isolation circuitry may be required between the shunt and the sensitive measurement and processing electronics.

[0004] Another type of current sensor uses an electromagnetic transducer to detect changes in the magnetic field generated by a current-carrying conductor. These rate-of-change field current sensors, such as Rogowski coils, do not require any physical connection to the current-carrying conductor and therefore can be isolated from the current-carrying conductor without any further isolation components.

[0005] However, because the rate of change of field sensors relies on magnetic field coupling, they are susceptible to interference from other changing magnetic fields near the sensor. For example, a second current-carrying conductor that is not the target of the measurement operation may pass near the Rogowski coil. The magnetic field generated by this second current-carrying conductor may couple into the Rogowski coil, affecting the coil's measurement accuracy.

[0006] A major challenge with Rogowski coils is their sensitivity to electrostatic or capacitive coupling from nearby AC conductors. For example, in utility meters, electrostatic coupling can be prevalent due to the positioning of the AC busbars, which carry the current to be measured but also the phase voltage, typically 240V. Through electrostatic coupling, the voltage on the busbars couples into the coils via stray capacitance, and due to the high voltage of the conductors, even small amounts of stray capacitance can cause erroneous signals in the sensor.

[0007] Rogowski coils or di / dt current sensors implemented on printed circuit boards or substrates are typically limited to a low number of turns or the area enclosed by each turn. This reduces the output amplitude of the current sensor. This makes it particularly susceptible to external noise sources such as electrostatic coupling, especially when measuring low currents.

[0008] Increasing the loop or turn area improves the minimum signal that can be measured practically, because the noise in the readout (thermal, flicker, quantization) electronics is finite, and the larger the signal, the better the signal-to-noise ratio (SNR) at similar electronics cost (power, area, cost). This is especially important in constrained applications where coil size, conductor size, or electronics power consumption are limited.

[0009] In PCB-implemented current sensors, it is difficult to increase the loop area when the limiting factor is the PCB thickness.

[0010] It is desirable to provide a current sensor implemented on a substrate with increased sensed signal amplitude, thereby improving immunity to noise. Summary of the Invention

[0011] According to a first aspect, there is provided a current sensor assembly comprising:

[0012] Each of the plurality of current sensors comprises: a substrate; a path for a conductor carrying current; and a plurality of measuring coils, each measuring coil being arranged to at least partially encircle the path of the conductor, wherein the plurality of current sensors are stacked such that, in use, a first signal induced in a first current sensor of the plurality of current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the plurality of current sensors by the current in the conductor.

[0013] According to a second aspect, a current measurement system is provided, the current measurement system comprising: a current sensor assembly, the current sensor assembly comprising:

[0014] Each of the plurality of current sensors comprises: a substrate; a path for a conductor carrying current; and a plurality of measuring coils, each measuring coil being arranged to at least partially encircle the path of the conductor, wherein the plurality of current sensors are stacked such that, in use, a first signal induced in a first current sensor of the plurality of current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the plurality of current sensors by the current in the conductor; and a measurement circuit coupled to the current sensor assembly, the measurement circuit being configured to receive an output of the current sensor assembly and determine the current in the conductor.

[0015] According to a third aspect, there is provided a current sensor assembly comprising:

[0016] Each of the plurality of current sensors includes: a substrate; a path for a conductor carrying current; and a plurality of measuring coils, each measuring coil being arranged to at least partially surround the path of the conductor, wherein each of the plurality of current sensors is substantially identical in design, and each of the plurality of current sensors includes a first surface and a second surface, wherein a first group of current sensors of the plurality of current sensors is oriented in the stack such that the first surface of each of the first group of current sensors is oriented in a first direction, wherein a second group of current sensors of the plurality of current sensors is oriented in the stack such that the first surface of each of the second group of current sensors is oriented in a second direction, the second direction being opposite to the first direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, wherein like reference numerals represent like parts, and wherein:

[0018] Figure 1 is a schematic diagram of a Rogowski coil;

[0019] Figure 2a This is a schematic diagram of the PCB implementation of the current sensor change rate;

[0020] Figure 2b yes Figure 2a Schematic diagram of the rate of change of the current sensor;

[0021] Figure 2c yes Figure 2a A simplified diagram of the rate of change of current in the medium;

[0022] Figure 3a is a substrate including a plurality of current measuring coils;

[0023] Figure 3b is included Figure 3a a rotating view of a substrate of a plurality of current measuring coils;

[0024] Figure 3c yes Figure 2a A schematic diagram of a current sensor in a first direction;

[0025] Figure 3d yes Figure 2a A schematic diagram of the current sensor in the second direction;

[0026] Figure 4a It is a current sensor composed of eight stacked substrates;

[0027] Figure 4b It is a current sensor composed of ten stacked substrates;

[0028] Figure 5This is a simplified exploded view of the four substrate couplings in the current sensor;

[0029] Figure 6 yes Figure 5 Schematic diagram of a four-substrate current sensor;

[0030] Figure 7 This is a simplified exploded view of the four substrate couplings in a current sensor using tooth-shaped through-holes.

[0031] Figure 8a This is a simplified exploded view of the four substrates in the current sensor, with the substrates coupled in another way;

[0032] Figure 8b yes Figure 8a Schematic diagram of a four-substrate current sensor;

[0033] Figure 9a is a schematic diagram of a current sensor comprising two semicircular measuring coils;

[0034] Figure 9b is a schematic diagram of a current sensor including two measuring coils;

[0035] Figure 10a Here is a view of a stack of baseboards in a mounting system;

[0036] Figure 10b Here is a view of another substrate stack in the mounting system;

[0037] Figure 11a is a view of a frame or fixture used to mount or stack substrates;

[0038] Figure 11b yes Figure 11a a view of a frame or fixture including a plurality of base plates;

[0039] Figure 11c yes Figure 11a A top view of the frame or fixture. DETAILED DESCRIPTION

[0040] Known Rogowski coils can be negatively affected by electrostatic and magnetically coupled noise, such as electromagnetic interference noise generated by other current-carrying conductors in close proximity to the Rogowski coil.

[0041] A current sensor implemented on a substrate or printed circuit board (PCB) can include one or more current measurement coils arranged to (completely or partially) surround the conductor being measured. The sensitivity of the current measurement coil is determined by the loop area (the area enclosed by each loop of the coil) and the number of loops. When providing a PCB-implemented current measurement coil, the coil is limited by the number of substrate layers and other manufacturing constraints, such as the minimum distance between conductors and the minimum size requirements for through-holes. This limits the opportunity to increase the number of loops or turns and the loop area.

[0042] To improve the sensitivity of PCB-implemented current sensors, two or more current sensors can be stacked or coupled. Each current sensor includes a substrate and a measurement coil implemented on the substrate, so that all substrates surround the conductor being measured. This can form a current sensor assembly. Each current sensor includes two or more current measurement coils that follow the same path around the current-carrying conductor. The current measurement coils included in each current sensor can be coupled to each other and to the measurement circuitry, allowing the signals to constructively add, providing a higher signal output compared to using a single substrate alone. This increases the sensitivity of the system because the current sensor is not limited by the use of a single substrate or current sensor.

[0043] The total number of current sensors or PCBs in each current sensor stack can be selected based on the desired sensitivity of the current sensor. The greater the number of PCBs or current sensors used, the higher the overall sensitivity of the current sensor, enabling it to measure lower currents.

[0044] Each current sensor in the current sensor assembly can be essentially identical, including the same current measurement coil. Because each current sensor, or the substrate underlying each current sensor, is identical, increasing the system's sensitivity can potentially utilize a larger number of PCBs or substrates without requiring further computer-aided design or modifications to each individual substrate. This allows the system to be modified in the field, with field engineers determining only the number of substrates required without having to modify the actual design of the current measurement coils contained within them. Furthermore, this results in a system that only requires the manufacture of a single substrate or PCB design.

[0045] The AC sensors or substrates in a substrate stack can be flipped, rotated, or provided in a different orientation relative to adjacent substrates. The current sensors are stacked so that, in use, the signal induced in a corresponding current sensor has an opposite polarity to the signal induced in the current sensor adjacent to it in the stack. This stacked arrangement, when the adjacent substrates are rotated or flipped, results in the measurement coils provided on each of the plurality of substrates having opposite polarity in their response to the magnetic field generated by the conductor being measured, when compared to the polarity of the measurement coils on adjacent substrates in the plurality of substrates. By mirroring or flipping each alternate substrate, interference picked up by the terminal connections on the edge of each substrate is canceled. In particular, the interference picked up on each odd-numbered board cancels the interference picked up on each even-numbered board. Thus, the odd- and even-numbered pairs of boards or substrates work together to actively add a desired electromagnetic field (EMF) from the current-carrying conductor while canceling undesired EMF.

[0046] Figure 1 is a schematic diagram of a known Rogowski coil. To measure the current I(t) flowing through a current-carrying conductor 100, a measuring coil 102 is arranged so that the current-carrying conductor 100 passes through the measuring coil. The measuring coil 102 is wound into a spiral, such that the loops or turns of the spiral enclose a cross-sectional area 104, A. The current-carrying conductor 100 can be, for example, a busbar.

[0047] As the current I(t) in current-carrying conductor 100 changes, the field generated by the current also changes. The positioning of the measuring coil results in a voltage induced in measuring coil 102 that is proportional to the rate of change of current dI / dt. Therefore, integrating the output v(t) of the measuring coil provides a value proportional to the current. Each turn or loop of the coil forms a measurement area 104 in a plane perpendicular to the travel of the current-carrying conductor, and the induced voltage is proportional to the area enclosed by the turn or loops.

[0048] However, the voltage induced in the measuring coil may be affected by external conductors that the user did not intend to measure.

[0049] Figure 1 The Rogowski coil is a single-ended Rogowski coil comprising a measuring coil 102 extending around a conductor 100. The current sensor may comprise more than one measuring coil and be arranged to provide a differential output.

[0050] The current sensor can be implemented on a substrate, such as a printed circuit board (PCB). The measuring coil and the loop of the measuring coil are provided by conductors on two or more layers of the PCB, with the conductors connected by vias between the two or more layers. Many different PCB layouts can be used in the present disclosure.

[0051] Figure 2aAn example of a PCB-implemented current sensor 200 is shown. The different patterns shown on current sensor 200 indicate that the conductors or conductive traces are implemented on different layers of the circuit board. By implementing the measurement coil on multiple layers, the coil can be formed, with the area between the layers contributing to the loop area of ​​the coil. Figure 2a The current sensor shown comprises four measuring coils coupled to generate a differential output signal.

[0052] Figure 2b An alternative view of a PCB-implemented current sensor 200 is shown. The current sensor includes four measuring coils 202 arranged to extend circumferentially around (at least partially) a current-carrying conductor 204. When the current sensor is implemented on a printed circuit board or substrate, the circuit board or substrate may include a path or hole suitable for the current-carrying conductor. Thus, the measuring coils 202 extend around the path of the current-carrying conductor.

[0053] The measuring coil 202 is coupled to a measuring circuit 206. The measuring circuit 206 is configured to receive the output of the measuring coil and integrate or otherwise process the output signal to determine the current in the current-carrying conductor 204. The measuring circuit 206 may be part of a larger utility meter, power meter, or current measurement system. Figure 2b The measurement circuit 206 shown in FIG is a differential amplifier, but the measurement circuit 206 may include any suitable measurement circuit. For example, the measurement circuit may include an offset generation circuit, an analog or digital integrator configured to integrate the output of the measurement coil to determine the measured current, an amplifier circuit, and other circuitry. The measurement circuit 206 may be a separate system from the current measurement coil and may be provided separately. For example, the measurement circuit 206 may be provided on a separate substrate or as part of a separate device from the measurement coil 202. Alternatively, all or part of the measurement circuit 206 may be provided on the same substrate as the measurement coil 202.

[0054] Figure 2c Schematic diagram of the current sensor 200 implemented in PCB is shown. Figure 2c As shown, the current sensor 200 includes four measuring coils 208-214. A first forward measuring coil 208 is coupled to a first return or reverse measuring coil 210, which runs around the conductor 204 in a circumferential direction opposite to the first forward measuring coil 208. A second forward measuring coil 214 is coupled to a second return measuring coil 212, which runs around the conductor 204 in a circumferential direction opposite to the second forward measuring coil 214. The terms forward and reverse are used herein to distinguish between the measuring coils, but it should be understood that all coils are measuring coils that facilitate detecting the current passing through the conductor 204 under test.

[0055] Reference node 222 of first return measurement coil 210 is coupled to reference node 224 of second return measurement coil 212 at terminal 216. These nodes are referred to as reference nodes because they can generally be coupled to a reference voltage or terminal. However, they may also be simply referred to as nodes or terminals. Terminal or node 216 can be coupled to a reference voltage, such as ground, or any other suitable reference. Although first return measurement coil 210 and second return measurement coil 212 are shown as directly coupled in FIG. 2C , these return measurement coils may not be directly connected or coupled when they are part of a larger current measurement system. Reference node 216 can be located external to the substrate on which measurement coil 202 is disposed.

[0056] The first forward measuring coil 208 is coupled to a first or positive output terminal or node 218 and the second forward measuring coil 214 is coupled to a second or negative output terminal or node 220. Thus, the current sensor is a differential current sensor.

[0057] Figures 2a-2c The current sensor shown is an example of a current sensor implemented on a single substrate or printed circuit board (PCB). The current sensor implemented on the substrate or PCB may include various means for coupling the loops of each current measuring coil to each other to form a coil. Other current sensors including two or more measuring coils on a single PCB may be provided and used in the following disclosure.

[0058] As mentioned above, increasing the sensitivity of PCB current sensors is highly desirable. This is particularly important in low-current applications where signal-to-noise ratio is limited. Increasing the loop area or number of loops in the current sensor can provide higher sensitivity. However, increasing the sensitivity of coils printed on a single PCB is limited by the maximum aspect ratio achievable with current PCB technology. The aspect ratio, which refers to the maximum number of turns that can be provided on a substrate, is limited by constraints such as the minimum via diameter, minimum conductive trace thickness, and minimum spacing between conductive traces. While increasing PCB thickness increases the loop area per turn, this typically comes at the expense of increasing the via size, resulting in a reduction in the number of turns.

[0059] To achieve higher sensitivity, multiple current measurement coils implemented on separate PCBs or substrates can be provided around a single current-carrying conductor or a path suitable for a current-carrying conductor. For example, two or more substrates can be stacked, layered, or grouped together. Each substrate can include multiple current measurement coils that run or travel around the conductor or path. Current measurement coils distributed across different substrates can be coupled together to provide more loops or turns around the current-carrying conductor. This helps overcome the maximum aspect ratio possible with a single PCB-implemented current sensor. Stacking, layering, or grouping PCBs in this manner can present numerous manufacturing and performance challenges.

[0060] Figure 3a A first substrate 300 is shown which includes a path or hole 302 adapted to receive a current carrying conductor. The substrate 300 may also be referred to as a current sensor, as the measuring coil implemented on the substrate is used to measure the current. Figure 3a The substrate shown includes a hole, but it should be understood that the current carrying conductor can also be provided on the substrate as a conductive trace between multiple layers of the substrate. Therefore, the path through the substrate can be any suitable hole or medium through which a conductive trace or conductor suitable for carrying the current to be measured can pass. The first substrate includes two or more measuring coils ( Figure 3a ), these coils are implemented across the layers of the substrate, arranged around the path 302. Figure 3a The substrate 300 is shown in a first orientation with a first side or surface of the substrate facing in a first direction (in this case, upward). Figure 3a , which is not visible in FIG. 1 , because it is the side or surface of the substrate 300 opposite to the first side or surface.

[0061] The first substrate 300 includes a first output terminal or node 304 and a second output terminal or node 306 located on a first side of the substrate 300. The first output terminal or node 304 can provide a first or positive output and the second output terminal or node 306 can provide a second or negative output (where the coils are differential measurement coils, as shown in FIG2 ). In the case where the substrate includes four measurement coils (e.g., as shown in FIG2 ), Figure 2c The first output terminal 304 may correspond to the first positive output terminal 218 , and the second output terminal 306 may correspond to the second negative output terminal 220 .

[0062] Figure 3b Shows Figure 3a The first substrate 300 is shown in different directions. The substrate 300 has been Figure 3a The orientation in the substrate is rotated or flipped 180 degrees. Thus, the second side or surface of the substrate is now visible and the first side or surface of the substrate is no longer visible.

[0063] The substrate 300 shown in the second orientation includes a third terminal 308 and a fourth terminal 310 located on the second side of the substrate 300. The third terminal 308 and the fourth terminal 310 on the second side of the substrate can be adapted to be coupled to a reference terminal. Figure 2c In the case of the differential arrangement, the third terminal or node 308 may correspond to the reference terminal or node 222, and the fourth terminal or node 310 may correspond to the reference terminal or node 224. Although these are separate nodes, they may generally be coupled together to form Figure 2c The differential arrangement of .

[0064] Thus, the substrate 300 includes four terminals 304-310 corresponding to the first output terminal 218 and the second output terminal 220 (+, - or first and second) and two terminals 222, 224. The two terminals 222, 224 are coupled to the reference connection in FIG. 2C, but as shown in FIG. Figure 3a and 3b As shown, they may not be connected to each other on the substrate. Depending on the number of measurement coils implemented on the substrate, an alternative number of input and output terminals may be provided. The terminals protrude or extend beyond the side or surface of current sensor 300. This allows them to be easily connected or coupled to other current sensors or measurement circuits. The terminals may protrude so that if current sensor 300 is flipped or rotated, the terminals will not align with each other. This is because the terminals are off-center on one side of current sensor 300.

[0065] In addition to the direction, Figure 3a and 3b The substrate 300 shown in FIG. 3 is the same substrate, and thus the current measuring coils on the substrate 300 are the same.

[0066] While the substrates 300 can be identical, it should be understood that the substrates can be similar rather than identical. For example, other circuitry, such as the measurement circuit 206, can be provided on one or more substrates 300. Furthermore, the current measurement coils provided on the substrates can be similar rather than identical. For example, rather than including identical measurement coils, the coils of the substrates can have similar turns per measurement coil (e.g., within 2%, 5%, or 10% of each other) or similar coil layouts.

[0067] Figure 3c A view of the current sensor shown in FIG2 in a first orientation is shown. As shown, four connections to the measuring coil (first or positive input 304, 218, second or negative input 306, 220, first reference terminal 208, 222, and second reference terminal 210, 224) are provided using pads or terminals on both sides of the substrate (four pads or terminals total). Figure 3d A view of the current sensor is shown in a second or flipped orientation, including pads or terminals viewed from a second side of the substrate.

[0068] Figure 4a and 4b A stack or group of printed circuit boards or substrates is shown. Each printed circuit board or substrate includes two or more current measuring coils around the same path 302 for a current carrying conductor. For example, Figure 2c As shown, each printed circuit board or substrate may include four measuring coils, but other numbers of measuring coils may be used. Each substrate may be connected to Figure 3aand 3b The substrates shown are the same. Alternatively, other substrates may be used.

[0069] Figure 4a 4 is a current sensor assembly 400 that includes eight current sensors implemented on circuit boards or substrates 402 , 404 . Figure 4a One of the substrates of the illustrated current sensor 400 includes measurement circuitry 406 .

[0070] Figure 4b There is a current sensor assembly 408 that includes ten current sensors implemented on printed circuit boards or substrates 402 , 404 . Figure 4b One of the illustrated substrates of current sensor 408 includes measurement circuitry 406. It should be understood that the number of substrates provided in current sensors 400 and 408 is merely exemplary, and any number of substrates may be stacked or layered in this manner. The substrates are stacked, layered, or grouped so that they overlap one another. The substrates are arranged so that they are all substantially centered around path 302 of the current-carrying conductor. In other words, the axis passing through the center of each substrate or through the center of path 302 may be the same for all substrates within the current sensor.

[0071] Alternating substrates in the substrate stack are flipped or rotated relative to adjacent substrates. For example, where the substrate stack includes N substrates, numbered 1-N relative to the first or last substrate in the stack, each even-numbered substrate 404 can be flipped relative to each odd-numbered substrate 402. For example, the even-numbered substrates 404 can be flipped relative to each odd-numbered substrate 402. Figure 3a The odd-numbered substrates 402 may be provided in the first direction shown. Figure 3b When the number N of substrates is a multiple of 2 or divisible by 2, it is ensured that the number of substrates provided in the first direction is the same as the number of substrates provided in the second direction.

[0072] Each of the plurality of substrates 402, 404 includes a first major surface and a second major surface (the planar surface of the PCB through which the vias extend to form the loops of the measurement coils). In other words, the major surfaces or planes of the substrates are perpendicular to the path 302 of the current-carrying conductors. A first orientation includes the first major surfaces of the substrates arranged along a first direction. A second orientation includes the second major surfaces arranged along the first direction. In other words, the plurality of substrates are stacked such that the first major surface of each substrate in the plurality of substrates is adjacent to the first major surface of an adjacent substrate in the plurality of substrates.

[0073] Each substrate 402, 404 is substantially identical and includes an identical current measurement coil. This stacked arrangement allows the measurement coils provided on each substrate of the plurality of substrates to respond to the magnetic field generated by the conductor in path 302 with opposite polarity compared to the polarity of the measurement coils on adjacent substrates in the plurality of substrates, if the adjacent substrates are rotated or flipped.

[0074] Using a common PCB or substrate design (ie all substrates including the same measurement coil layout) reduces manufacturing and design complexity, as a single substrate can be produced multiple times and then stacked in the previously described arrangement.

[0075] While the current measurement coils are depicted as identical, it should be understood that minor differences may exist between substrates. For example, the number of turns, connection holes, or mounting method of each coil may differ. Optimal performance is achieved when the measurement coils implemented on all substrates have the same layout, but minor differences may be acceptable in certain situations where performance is less critical. Furthermore, one or more substrates may include measurement circuitry 406 coupled to the measurement coils. This may be active or passive measurement circuitry 206, which may include, for example, one or more amplification, integration, filtering, or buffering components. Furthermore, the layout of the measurement coils on each substrate may differ slightly.

[0076] Although Figure 4a and 4b While current sensors comprising eight and ten stacked substrates or PCBs are outlined, each current sensor can include any number of substrates or PCBs, such as two, four, six, eight, ten, twelve, or fourteen substrates, each containing two or more measuring coils. The total number of PCBs in each stack can be selected based on the desired sensitivity of the current sensor, with more PCBs or substrates being used when higher sensitivity is required. Adding a greater number of PCBs or substrates does not require further computer-aided design or changes to each individual substrate—the design is modular, and the total number of PCBs can be adjusted. This allows the system to be modified in the field, with field engineers determining only the number of substrates required without having to modify the actual design of the current measuring coils contained on the substrates.

[0077] The current measurement coils included on each substrate can be coupled to each other and to the measurement circuitry so that the signals constructively add, providing a higher signal output than using a single substrate alone. Figure 4a and 4b , but it will be appreciated that the measurement circuitry 406 may be provided on one of the substrates, distributed across the substrates, or provided as part of an external measurement system that does not form part of the substrate.

[0078] To provide electrical insulation between the substrates in the stack, a protective or insulating film, such as a polyimide film cut to the shape of the substrate's outline, may be placed between each plate of the stack. Alternatively, the substrate may include an insulating layer as an outer or surface layer as part of its structure.

[0079] Figure 5 An exploded view of an example of a stacked current sensor 500 comprising four substrates 502-508 is shown. Each substrate comprises four measuring coils, such as Figure 2a 、 2b The layout is the same as shown in 2c - two forward coils and two return coils. However, the first return coil and the second return coil are not coupled to each other on the substrate. In other words, Figure 2c The third node 222 and the fourth node 224 are not coupled together. The measurement coils are shown in two separate locations on the substrate, with the first forward and return coils in one area and the second forward and return coils in a second area, but this is purely for ease of understanding. It should be understood that the measurement coils (forward and return) on each substrate are arranged around the path of the conductor, as shown in Figure 2. In addition, the four substrates 502-508 are arranged so that all measurement coils on the four substrates travel around the same path of the conductor.

[0080] Each plate in the stack is flipped. For example, a vertical stack of four plates would include plates 502, 504, 506, and 508 stacked from bottom to top. Plates 502 and 506 (odd-numbered plates) would face upward, or in a first orientation, while plates 504 and 508 (even-numbered plates) would face downward, or in a second orientation. This is clearly seen in the positioning of the first and second measurement coils on each of the plates 502-508.

[0081] For clarity, Figure 5 Substrates 502-508 are shown separated by gaps. When connected, the substrates 502-508 can be provided so that they are stacked together with minimal gaps or distances between the substrates, as shown in Figure 4. As shown in Figure 3, the terminals on each substrate are labeled with the specific coil to which each terminal is coupled.

[0082] Each measuring coil included on each substrate is coupled to terminals 510 at the outer edge or circumference of each substrate. Figure 3a and 3bThe first input terminal 304, second input terminal 306, third terminal 308, and fourth terminal 310 shown in FIG are identical. The coupling between the coil and the terminals creates undesirable loop regions that are susceptible to external, unwanted magnetic fields. By mirroring or flipping each alternative substrate, the interference of the loop on the terminals 510 on each odd-numbered board cancels the interference of the loop on the terminals 510 on each even-numbered board. Thus, the odd and even pairs of circuit boards work together to actively add the desired electromagnetic field (EMF) from the current-carrying conductor while canceling the undesirable EMF.

[0083] The current measuring coils on separate substrates are coupled together, and the output terminals of the complete current sensor stack 500 are provided on substrate 502 (two output terminals, referred to as positive and negative terminals (+ and -), and two reference terminals (REF) suitable for coupling to the system common mode).

[0084] Figure 6 Detailed display Figure 5 Schematic diagram of each substrate or plate and how the measurement coils on each substrate 502-508 are connected.

[0085] By flipping or rotating the coils, the polarity of each coil is reversed relative to its response to the desired magnetic field from the conductor. The dots in the diagram represent the polarity of each measurement coil and show how the polarity switches with each substrate. The connections for each coil take this into account to ensure that the desired EMF signals are additive.

[0086] Figure 6 The diagram shows how the individual measurement coils on the four substrates are coupled to each other and to external circuitry, such as the differential amplifier 602. It should be understood that the measurement circuitry or external circuitry 602 can be located on one of the substrates or separately. The complete wiring path begins at the two pins of the differential amplifier, representing the positive and negative terminals (+ and -) of the external measurement circuitry. Signal lines are routed from each pin and follow a path through the stack of substrates, ultimately terminating at a common reference point. The positive input terminal is coupled to the first forward and return measurement coils on the first substrate 502. The first return coil on the first substrate is then coupled to the first forward and return coils on the third substrate 506. The first return coil on the third substrate is then coupled to the second forward and return coils 508 on the fourth substrate. The second return coil on the fourth substrate is then coupled to the second forward and second return coils on the second substrate 504. The second return coil on the second substrate is then coupled to the reference terminal.

[0087] In this way, the measurement coils on the odd-numbered substrates are coupled to each other in a first direction through the substrate stack (in this case, upwards) from the first output, or positive, terminal. At the top of the substrate stack, the measurement coils on the third and fourth substrates are coupled to each other, while the measurement coils on the even-numbered substrates are connected to the reference terminal in a second direction through the substrate stack (in this case, downwards). This ensures that the positive, negative, and reference terminals are all located adjacent to each other on the same substrate, rather than at opposite ends of the substrate stack.

[0088] The measurement coil coupled to the second, or negative, output terminal is coupled in a similar manner. The negative input terminal is coupled to the second forward and reverse measurement coils on the first substrate 502. The second return coil on the first substrate is then coupled to the third forward and return coils on the third substrate 506. The second return coil on the third substrate is then coupled to the first forward and return coils 508 on the fourth substrate. The first return coil on the fourth substrate is then coupled to the first forward and return coils on the second substrate 504. The second return coil on the second substrate 504 is then coupled to the reference terminal.

[0089] like Figure 5 As shown and described above, the wiring or connections between coils may skip across the circuit board using vias. This allows connections along a first direction to skip across every other substrate, with connections along a second direction made on the remaining substrates. Vias may be located on the substrates. These vias allow measurement coils on non-adjacent substrates to couple to each other. For example, vias located on the second substrate 504 allow the first return measurement coil on the first substrate 502 to be coupled to the first forward measurement coil on the third substrate.

[0090] The positive and negative traces (the coil connections from each positive, or first, and negative, or second, terminal) follow the same path, meaning they should be close together and in the same direction as they travel through the battery stack. This minimizes electrostatic noise coupling. Furthermore, any unintended loop areas created by the interconnects can be designed so as not to result in differential EMF voltages in response to external magnetic fields. This minimizes magnetic noise coupling.

[0091] Figure 5 Each substrate shown may include a disconnect between the input terminals. This connection may be populated or shorted 512 on the top or end plate of the substrate stack (in this case the fourth substrate 508). This allows for the top substrate (e.g. Figure 6 ) and a previous substrate (e.g., Figure 6 Since the disconnected connections are present on all substrates, only one substrate needs to be manufactured, with the short circuit being provided on one of the substrates using, for example, a manually added short circuit or a soldered connection.

[0092] Figure 5 The substrates 502-508, and more specifically, the measurement coils provided on the substrates, are coupled or connected together using a Z-interconnect. A Z-interconnect involves bonding the substrates together using some form of conductive material on the surface of each substrate. Terminals 304-310 are configured as conductive pads. To form a connection between the substrates, solder can be placed on the surface of the terminal pads on each substrate 502-508. The substrates can then be placed one on top of the other, and the solder reflows to connect the measurement coils on each substrate. This simplifies the manufacturing process.

[0093] Figure 7 Shows Figure 5 Alternative current sensor 700, in which the substrate and the measuring coil are connected in an alternative manner. Figure 5 In this system, measurement coils on non-adjacent substrates are coupled or connected using through-holes. Substrates 702-708 include castellated through-holes or pads 710 on the periphery of the substrates. Castellated through-holes 710 can be semi-through-holes, which allow a wire, solder, or segment to pass through one substrate without providing an electrical connection to the substrate. Thus, non-adjacent substrates or current sensors can be coupled to each other via castellated through-holes 710, allowing terminals or pads on two non-adjacent substrates to couple via castellated through-holes 710 on a substrate located between the two non-adjacent substrates.

[0094] Using castellated vias instead of the previously described Z-shaped interconnects can be simpler to manufacture, for example using hand soldering in a laboratory.Other connection types between substrates can be used - Z-shaped interconnects and castellated vias are just two examples.

[0095] Figure 8a is a schematic diagram of the current sensor 800, and Figure 5 and Figure 7 Compared to the current sensor shown, the current sensor 800 includes an alternative coupling of the current measuring coils. The current sensor includes four substrates 804, 806, 808 and 810. Figure 5 and Figure 7 In Figure 8 , the measurement coils on odd-numbered substrates are coupled in one direction, while the measurement coils on even-numbered substrates provide a loop connection (so that the output terminals are at one end of the substrate stack). In Figure 8 , the measurement coils are coupled sequentially in the order of the boards are stacked, with the positive and negative, or first and second, measurement coils for each substrate coupled sequentially from one end of the substrate stack to the other. A single conductor or loop 802 is then provided so that the common mode or reference terminal is routed adjacent to the positive and negative connection terminals of the substrate stack.

[0096] Figure 8b Yes Display Figure 8aSchematic diagram of the measurement coil coupling of current sensor 800. The first or positive output terminal is sequentially coupled to the first positive and return coils on each of the first substrate 804, the second substrate 806, the third substrate 808, and the fourth substrate 810. The second or negative output terminal is sequentially coupled to the second positive and return coils on each of the first substrate 804, the second substrate 806, the third substrate 808, and the fourth substrate 810. The return conductor provides routing for the common mode or reference voltage terminal to the fourth substrate 810.

[0097] This eliminates the need to use vias as the coil on one substrate couples to the coil on the adjacent substrate, but requires a return or common mode connection from one end of the substrate stack to the other to allow connection to the reference terminal. Figure 5 and Figure 7 In the case of a CMOS sensor, the loop connection is provided using the measuring coil itself.

[0098] Figure 2-8 outlines a current sensor, each substrate includes four measuring coils, according to Figure 2c (It is worth noting that the return coils on each substrate are not coupled to each other, but are coupled to the measurement coils on different substrates.) It should be understood that other arrangements of the measurement coils on each substrate may be used. For example, any PCB-implemented current sensor that includes two or more measurement coils on each substrate may be implemented using the stacked PCB implementation described previously. In the case of a single-ended current measurement system, each substrate may include one forward and one return coil, with the coils arranged in a Figure 6 or Figure 8b Alternatively, each substrate may comprise two measuring coils in the same direction (forward or reverse) or in alternating directions (forward and reverse).

[0099] Figure 9a An alternative PCB implementation of current measurement coils is shown. Each substrate includes a first measurement coil 902 and a second measurement coil 904. Each measurement coil 902, 904 extends approximately 180 degrees around the path of the current-carrying conductor 204. The ends of each measurement coil 902, 904 are coupled to corresponding return conductors 908, 910, which extend in opposite directions along the circumferential path of the measurement coils. Return conductors 908, 910 provide improved suppression of magnetic fields passing through the PCB surface by acting as cancellation loops relative to the loop created by the circumferential path of the measurement coils. Each substrate includes two semicircular measurement coils and two return or counter conductors.

[0100] Since the measuring coil is a semicircle, the output of the current sensor is susceptible to electrostatic coupling due to the non-central positioning of the current-carrying conductor.

[0101] Supplied in stacked arrangement Figure 9a The current measuring coils 900 are flipped relative to each adjacent substrate, resulting in positive semicircular coils 902 and negative semicircular coils 904 alternating sides of the current-carrying conductor 204 with each substrate. For example, on a first substrate, the first measuring coil 902 is located on a first side of the conductor 204, while on a second flipped substrate, the second measuring coil 902 is located on a second side of the conductor 204. This reduces sensitivity to variations in conductor positioning.

[0102] Figure 9b An alternative PCB-implemented current measurement coil that can be used in a stacked current sensor is shown. Each substrate includes a first measurement coil 908 and a second measurement coil 910. This alternative PCB-implemented current sensor lacks both a return wire and a return coil, resulting in a large common-mode voltage when exposed to an external magnetic field on the PCB surface. By flipping alternate circuit boards, for example, flipping every odd-numbered circuit board, the common-mode voltage on the even-numbered circuit boards can be offset by the single-mode voltage on the odd-numbered circuit boards.

[0103] Figure 10a A current sensor system 1000 or a mounting system for a current sensor is shown. The current sensor described with respect to any of the preceding figures may be mounted on a Figure 10a In the mounting system shown, system 1000 includes a first support substrate 1002 and a second support substrate 1004. First support substrate 1002 and second support substrate 1004 are coupled to each other using a plurality of mechanical supports 1008 or mechanical support elements. The plurality of mechanical support elements 1008 can be posts or other support structures that connect the corners of support substrates 1002 and 1004 to each other. Mechanical supports 1008 can also be coupled to other locations on the substrate. The previously described current sensor assembly can be stacked or positioned between first support substrate 1002 and second support substrate 1004.

[0104] First and second support substrates 1002 and 1004 are used to sandwich, hold together, support, or frame the multiple substrates 1006 that form the stacked current sensor. The multiple substrates, including the measurement coils, are stacked as previously described and then placed between support substrates 1002 and 1004. In this manner, multiple substrates 1006 are stacked together. Support substrates 1002 and 1004 and mechanical support elements 1008 all serve to support the substrates.

[0105] The support substrate 1004 may be another PCB including a current measuring coil forming part of the stack. Figure 10a and Figure 10bAs shown, the support substrate 1004 may additionally or alternatively include measurement electronics 1010 to determine the current through the conductor being measured, or include electronics 1010 that form part of a wider utility meter or power meter. The support substrate may include an electrostatic shield, such as a ground plane, to reduce noise coupling into the current measurement system.

[0106] Each individual PCB included in the stack can be edge plated to provide shielding. If used in locations where high voltages could electrostatically couple to the PCB di / dt sensor, additional shielding vias or a shielding copper layer can be included. This shields the sensor and current measurement coil located within the shield. Edge plating can be used to provide shielding along non-major surfaces of the substrate.

[0107] Figure 11a A frame or fixture 1100 is shown for supporting or mounting multiple substrates forming a current sensor. Frame 1100 includes a base 1102, an outer wall 1104, and a central tube or protrusion 1106. Central or intermediate tube or protrusion 1106 is adapted to receive a current-carrying conductor or a conductor to be measured. Frame 1100 is configured to hold a stack of multiple current sensors 1108, such that each current sensor remains in a fixed position relative to the other current sensors in the stack. This can be achieved in a variety of different ways.

[0108] like Figure 11b As shown, multiple substrates 1108 can be stacked on frame 1100. The multiple substrates include holes or paths for current-carrying conductors, which are mounted around a central tube or protrusion 1106 of frame 1100. The shape of central tube or protrusion 1106 can be substantially the same as the path 302 of the conductors in the substrates including the measuring coils. Outer wall 1104 can be shaped to surround substrates 1108. In other words, the cross-sectional profile of central or intermediate tube or protrusion 1106 matches at least a portion of the cross-sectional profile of each current sensor 1108. This allows current sensors 1108 to be slotted or stacked onto frame 1100. The same is true for outer wall 1104, whose cross-sectional shape matches at least a portion of the outer perimeter of each current sensor 1108.

[0109] The outer wall 1104 of the frame 1100 may include one or more grooves, protrusions, or channels 1110. The plurality of substrates 1108 may include external protrusions, grooves, or channels on one or more sides that are arranged to fit within the grooves, protrusions, or channels of the outer wall 1104. This secures the substrates 1108 to the outer wall 1104 and ensures that the substrates are positioned on the frame in the correct orientation. Any suitable engagement portion may be provided on the frame 1100 and the current sensors 1108 such that the engagement portion on the frame 1100 corresponds to the engagement portion of each current sensor 1108 or is configured to engage with an engagement portion on each current sensor 1108.

[0110] The frame 1100 shown in Figure 11 can be used to hold multiple PCBs or substrates in place. Alternatively, the frame 1100 can be a fixture used during the assembly process and removed after assembly (once the PCBs are coupled or connected to each other, such as by soldering).

[0111] The frame or fixture 1100 can be used as a protective housing after manufacture and removed before the current sensor is installed in place. The frame 1100 can also incorporate other features such as mounting holes or flanges, clamps, cable routing and retention features, electrical shielding, electrical isolation, etc.

[0112] A layer of soft material, such as foam, may also be inserted between the PCB and the frame or fixture 1100 to cushion the current sensor from mechanical shock.

[0113] The current sensor, including multiple PCBs or substrates, and any cables can also be encapsulated, contained within, or surrounded by a protective material, such as epoxy or silicone. This protective material can be provided within a sealed version of the frame or fixture 1100. The protective material can provide weatherproofing for outdoor or harsh environments.

[0114] While the previous description depicts a current sensor comprised of multiple substrates or PCBs, each containing multiple measuring coils, it should be understood that the design can be embedded within a larger single PCB structure with a high layer count. This can be achieved through a large multilayer design or by using other advanced PCB manufacturing techniques, such as high-density interconnect (HDI) or Z-connect technology, to create an effectively large PCB.

[0115] With each additional substrate, the amplitude of the signal generated by the measuring coil effectively doubles. This increased sensitivity allows for accurate measurement of smaller currents. Coupling the measuring coils of multiple substrates in series increases the system's series impedance, but this can be compensated for in the processing electronics. For example, a temperature correction factor can be implemented in the processing electronics to enable the electronics to track temperature changes due to the increased series resistance.

[0116] Various modifications may be made to the above examples, whether by adding, deleting, or substituting features, to provide further examples, any and all of which are intended to be included in the appended aspects.

[0117] Disclosure:

[0118] 1. A current sensor, comprising:

[0119] a plurality of substrates, wherein each substrate of the plurality of substrates comprises:

[0120] the path of current-carrying conductors;

[0121] a plurality of measuring coils advancing in a circumferential direction around the path of the current-carrying conductor;

[0122] wherein the plurality of substrates are stacked such that a plurality of substrates of the plurality of substrates are rotated relative to adjacent substrates of the plurality of substrates.

[0123] 2. The current sensor according to aspect 1, wherein the plurality of substrates includes one or more even-numbered substrates and one or more odd-numbered substrates.

[0124] 3. The current sensor according to aspect 2, wherein the plurality of substrates are stacked such that each even-numbered substrate is stacked next to an odd-numbered substrate.

[0125] 4. The current sensor according to aspect 2 or aspect 3, wherein the even-numbered substrates are stacked in a first direction, and wherein the odd-numbered substrates are stacked in a second direction.

[0126] 5. A current sensor according to aspect 4, wherein each substrate of the plurality of substrates includes a first major surface and a second major surface, and wherein the first orientation includes the first major surface of the substrate being arranged in a first direction, and wherein the second orientation includes the second major surface of the substrate being arranged in the first direction.

[0127] 6. The current sensor of aspect 1, wherein each of the plurality of substrates comprises a first major surface and a second major surface, and wherein the plurality of substrates are stacked such that the first major surface of each of the plurality of substrates is adjacent to the first major surface of an adjacent one of the plurality of substrates.

[0128] 7. A current sensor according to any of the preceding aspects, wherein the plurality of substrates are stacked such that the plurality of measuring coils of each substrate of the plurality of substrates have opposite polarities in their response to the magnetic field generated by the conductor relative to the plurality of measuring coils of adjacent substrates of the plurality of substrates.

[0129] 8. The current sensor according to any preceding aspect, wherein a plurality of measuring coils on the one or more even-numbered substrates are coupled to the one or more even-numbered substrates.

[0130] 9. The current sensor according to any preceding aspect, wherein the plurality of measurement coils on the one or more odd-numbered substrates are coupled to the plurality of measurement coils on the one or more odd-numbered substrates.

[0131] 10. The current sensor according to any of the preceding aspects, wherein the plurality of measuring coils are coupled to each other using a Z-interconnection.

[0132] 11. The current sensor according to any one of aspects 1 to 8, wherein the plurality of substrates include tooth-shaped through-holes located on outer peripheries of the plurality of substrates, and wherein the plurality of measuring coils are coupled to each other using connections between the tooth-shaped through-holes.

[0133] 12. The current sensor according to any one of the preceding aspects, wherein the plurality of measuring coils of the plurality of substrates have the same design.

[0134] 13. The current sensor according to any one of the preceding aspects, wherein the plurality of measuring coils advance in the same manner in a circumferential direction around the path of the current carrying conductor on each of the plurality of substrates.

[0135] 14. The current sensor according to any preceding aspect, wherein one of the plurality of substrates further comprises a measurement circuit coupled to the plurality of measurement coils.

[0136] 15. The current sensor according to any one of the preceding aspects, wherein the current sensor further comprises:

[0137] Another substrate having a plurality of substrates mounted thereon includes a measurement circuit coupled to the plurality of measurement coils.

[0138] 16. The current sensor according to any one of the preceding aspects, further comprising:

[0139] a first supporting substrate;

[0140] a second supporting substrate;

[0141] A plurality of mechanical supports couple the first support substrate and the second support substrate, wherein the plurality of substrates are stacked between the first support substrate and the second support substrate.

[0142] 17. The current sensor of aspect 16, further comprising measurement circuitry on at least one of the first support substrate and the second support substrate.

[0143] 18. The current sensor according to any one of the preceding aspects, further comprising:

[0144] A framework, comprising:

[0145] One or more grooves, slots or holes are arranged to interface with the plurality of substrates to enable the plurality of substrates to be stacked on the frame.

[0146] A second set of aspects of the present disclosure is provided below:

[0147] 1. A current sensor assembly comprising:

[0148] Each of the plurality of current sensors comprises:

[0149] substrate;

[0150] a path for conductors carrying electric current; and

[0151] a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor,

[0152] The plurality of current sensors are stacked such that, in use, a first signal induced in a first current sensor of the plurality of current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the plurality of current sensors by the current in the conductor.

[0153] 2. The current sensor assembly of aspect 1, wherein the first current sensor and the second current sensor are adjacent in the stack of multiple current sensors.

[0154] 3. A current sensor assembly according to any preceding aspect, wherein the first current sensor and the second current sensor of the plurality of current sensors have different relative orientations such that, in use, the first signal and the second signal have different polarities.

[0155] 4. A current sensor assembly according to any of the preceding aspects, wherein the stacked plurality of current sensors further comprises a third current sensor, the third current sensor being arranged so that, in use, a third signal induced in the third current sensor by the current in the conductor has the same polarity as the signal induced in the first current sensor.

[0156] 5. The current sensor assembly of aspect 4, wherein the second current sensor is located between the first current sensor and the third current sensor in the stack.

[0157] 6. The current sensor assembly of aspect 5, wherein the first current sensor is electrically coupled to the third sensor.

[0158] 7. The current sensor assembly of aspect 5, wherein the first current sensor is electrically coupled to the second current sensor.

[0159] 8. The current sensor assembly of aspect 7, wherein the second current sensor is electrically coupled to the third current sensor.

[0160] 9. The current sensor assembly according to any preceding aspect, wherein the substrate of each of the plurality of current sensors comprises a first surface and an opposing second surface.

[0161] 10. A current sensor assembly according to aspect 9, wherein the first current sensor is oriented so that its first surface faces a first direction in the stack and its second surface faces a second direction in the stack, and the second sensor is oriented so that its first surface faces the second direction in the stack and its second surface faces the first direction in the stack, wherein the first direction is opposite to the second direction.

[0162] 11. A current sensor assembly according to any preceding aspect, wherein each of the plurality of current sensors is substantially identical in design.

[0163] 12. The current sensor assembly according to any preceding aspect, wherein the layout of the plurality of measuring coils on each substrate of the plurality of substrates is substantially the same.

[0164] 13. The current sensor assembly according to any preceding aspect, wherein at least one substrate of the plurality of substrates comprises a measurement circuit coupled to a plurality of measurement coils on the substrate.

[0165] 14. The current sensor assembly according to any preceding aspect, wherein at least one measuring coil of the plurality of measuring coils on each current sensor of the plurality of current sensors is coupled to at least one measuring coil of the plurality of measuring coils on at least one other current sensor of the plurality of current sensors.

[0166] 15. The current sensor assembly according to any preceding aspect, wherein each current sensor of the plurality of current sensors is electrically coupled to at least one other current sensor of the plurality of current sensors using at least one Z-interconnect.

[0167] 16. The current sensor assembly according to any one of the preceding aspects, wherein each substrate of the plurality of current sensors comprises a tooth-shaped through hole located on an outer periphery of the substrate.

[0168] 17. The current sensor assembly of aspect 16, wherein each current sensor of the plurality of current sensors is coupled to at least one other current sensor of the plurality of current sensors using the castellated via.

[0169] 18. The current sensor assembly according to any one of the preceding aspects, wherein the current sensor further comprises:

[0170] A first supporting substrate is provided on which the plurality of current sensors are stacked.

[0171] 19. The current sensor assembly of aspect 18, further comprising:

[0172] a second supporting substrate; and

[0173] A plurality of mechanical supports couple the first support substrate and the second support substrate, wherein the stacked plurality of current sensors are located between the first support substrate and the second support substrate.

[0174] 20. The current sensor package of aspect 19, further comprising measurement circuitry on at least one of the first support substrate and the second support substrate.

[0175] 21. The current sensor assembly according to any one of the preceding aspects, further comprising:

[0176] A frame is arranged to hold the stacked plurality of current sensors such that each current sensor is held in a fixed position relative to the other current sensors of the stacked plurality of current sensors.

[0177] 22. A current sensor assembly according to aspect 21, wherein the frame includes at least one engaging portion, the engaging portion being configured to engage with at least one corresponding engaging portion on each of the stacked plurality of current sensors so as to maintain each current sensor of the plurality of current sensors in a fixed position relative to the frame and the other current sensors of the plurality of current sensors.

[0178] 23. The current sensor assembly of aspect 21 or 22, wherein at least a portion of a cross-sectional profile of each of the stacked plurality of current sensors matches at least a portion of a cross-sectional profile of the frame.

[0179] 24. A current sensor assembly according to any preceding aspect, wherein the current sensor assembly comprises a differential output, and wherein the voltage sensor is electrically coupled such that:

[0180] A first signal induced in the first current sensor by the current in the conductor and a second signal induced in the second current sensor by the current in the conductor are additively combined at the differential output.

[0181] 25. The current sensor assembly of aspect 24, wherein the current sensor is electrically coupled such that:

[0182] A first noise signal induced in the first current sensor by a noise source and a second noise signal induced in the second current sensor by the noise source are destructively combined at the differential output.

[0183] 26. A current measurement system, comprising: a current sensor assembly, wherein the current sensor assembly comprises:

[0184] Each of the plurality of current sensors comprises:

[0185] substrate;

[0186] a path for conductors carrying electric current; and

[0187] a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor,

[0188] wherein the plurality of current sensors are stacked such that, in use, a first signal induced in a first current sensor of the plurality of current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the plurality of current sensors by the current in the conductor;

[0189] A measurement circuit is coupled to the current sensor assembly, the measurement circuit being configured to receive the output of the current sensor assembly and determine the current in the conductor.

[0190] 27. A current sensor assembly comprising:

[0191] Each of the plurality of current sensors comprises:

[0192] substrate;

[0193] a path for conductors carrying electric current; and

[0194] a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor,

[0195] wherein each of the plurality of current sensors is substantially identical in design, and each of the plurality of current sensors comprises a first surface and a second surface,

[0196] wherein a first group of current sensors of the plurality of current sensors are oriented in the stack such that a first surface of each of the first group of current sensors is oriented in a first direction,

[0197] Wherein a second group of current sensors of the plurality of current sensors is oriented in the stack such that a first surface of each of the second group of current sensors is oriented in a second direction, the second direction being opposite to the first direction.

[0198] 28. The current sensor assembly of aspect 27, wherein each of the first set of current sensors is arranged so as to be adjacent in the stack to a current sensor of the second set of current sensors.

Claims

1. A current sensor assembly comprising: A plurality of stacked current sensors, each of the plurality of current sensors comprising: substrate; a path for conductors carrying electric current; and a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor, The multiple current sensors are stacked so that, in use, a first signal induced in a first current sensor of the multiple current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the multiple current sensors by the current in the conductor. 2 . The current sensor assembly of claim 1 , wherein the first current sensor and the second current sensor are adjacent in the stack of the plurality of current sensors.

3. A current sensor assembly according to any preceding claim, wherein the first current sensor and the second current sensor of the plurality of current sensors have different relative orientations such that, in use, the first signal and the second signal have different polarities.

4. A current sensor assembly according to any one of the preceding claims, wherein the stacked plurality of current sensors further comprises a third current sensor, the third current sensor being arranged such that, in use, a third signal induced in the third current sensor by the current in the conductor has the same polarity as the signal induced in the first current sensor. 5 . The current sensor assembly of claim 4 , wherein the second current sensor is located between the first current sensor and the third current sensor in the stack. The current sensor assembly of claim 5 , wherein the first current sensor is electrically coupled to the third sensor. 7 . The current sensor assembly of claim 5 , wherein the first current sensor is electrically coupled to the second current sensor. 8 . The current sensor assembly of claim 7 , wherein the second current sensor is electrically coupled to the third current sensor.

9. A current sensor assembly according to any one of the preceding claims, wherein the substrate of each of the plurality of current sensors includes a first surface and an opposing second surface, and wherein the first current sensor is oriented so that its first surface faces a first direction in the stack and its second surface faces a second direction in the stack, and wherein the second sensor is oriented so that its first surface faces the second direction in the stack and its second surface faces the first direction in the stack, wherein the first direction is opposite to the second direction.

10. A current sensor assembly according to any preceding claim, wherein each of the plurality of current sensors is substantially identical in design.

11. The current sensor package according to any one of the preceding claims, wherein the layout of the plurality of measuring coils on each substrate of the plurality of substrates is substantially identical.

12. The current sensor assembly of any of the preceding claims, wherein at least one measuring coil of the plurality of measuring coils on each current sensor of the plurality of current sensors is coupled to at least one measuring coil of the plurality of measuring coils on at least one other current sensor of the plurality of current sensors.

13. The current sensor assembly of any one of the preceding claims, wherein each current sensor of the plurality of current sensors is electrically coupled to at least one other current sensor of the plurality of current sensors using at least one Z-interconnect.

14. The current sensor package according to any one of the preceding claims, wherein each substrate of the plurality of current sensors comprises a tooth-shaped through hole located on the periphery of the substrate.

15. The current sensor assembly according to any one of the preceding claims, wherein the current sensor further comprises: A first supporting substrate is provided on which the plurality of current sensors are stacked.

16. The current sensor assembly of claim 15, further comprising: a second supporting substrate; and A plurality of mechanical supports couple the first support substrate and the second support substrate, wherein the stacked plurality of current sensors are located between the first support substrate and the second support substrate.

17. A current sensor assembly according to any one of the preceding claims, further comprising: A frame is arranged to hold the stacked plurality of current sensors such that each current sensor is held in a fixed position relative to the other current sensors of the stacked plurality of current sensors.

18. A current sensor assembly according to any one of the preceding claims, wherein the current sensor assembly comprises a differential output, and wherein the voltage sensor is electrically coupled such that: a first signal induced in the first current sensor by the current in the conductor and a second signal induced in the second current sensor by the current in the conductor are additively combined at the differential output; and A first noise signal induced in the first current sensor by a noise source and a second noise signal induced in the second current sensor by the noise source are destructively combined at the differential output.

19. A current measurement system, comprising: A current sensor assembly, the current sensor assembly comprising: Each of the plurality of current sensors comprises: substrate; a path for conductors carrying electric current; and a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor, wherein the plurality of current sensors are stacked such that, in use, a first signal induced in a first current sensor of the plurality of current sensors by the current in the conductor has a different polarity than a second signal induced in a second current sensor of the plurality of current sensors by the current in the conductor; A measurement circuit is coupled to the current sensor assembly, the measurement circuit being configured to receive the output of the current sensor assembly and determine the current in the conductor.

20. A current sensor assembly comprising: Each of the plurality of current sensors comprises: substrate; a path for conductors carrying electric current; and a plurality of measuring coils, each measuring coil being arranged to at least partially follow the path of the conductor, wherein each of the plurality of current sensors is substantially identical in design, and each of the plurality of current sensors comprises a first surface and a second surface, wherein a first group of current sensors of the plurality of current sensors are oriented in the stack such that a first surface of each of the first group of current sensors is oriented in a first direction, Wherein a second group of current sensors of the plurality of current sensors is oriented in the stack such that a first surface of each of the second group of current sensors is oriented in a second direction, the second direction being opposite to the first direction.

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