Transducer having magnetic FLUX concentrator

Abstract

A transducer system having a magnetic core that includes a gap between two end surfaces of the magnetic core. A first cap structure is arranged adjacent to a first end surface and a second cap structure is arranged adjacent to the second end surface. The first and second cap structures each includes a material having a magnetic permeability higher than that of air. The first cap structure includes a first flux concentration surface and the second cap structure includes a second flux concentration surface that faces the first flux concentration surface. A magnetic flux measurement device is positioned between the first flux concentration surface and the second flux concentration surface. The cap structures concentrate magnetic flux in the magnetic core onto the respective concentration surfaces. The concentration surfaces enable more accurate measurement of the magnetic flux.

Description

[0001] TRANSDUCER HAVING MAGNETIC FLUX CONCENTRATOR

[0002] BACKGROUND

[0003] Technical Field

[0004] The present disclosure relates generally to current measurement.

[0005] Description of the Related Art

[0006] In existing current transducers that measure current in a conductor, a magnetic flux generated by a primary current that flows along a magnetic core and is measured in an air gap of the magnetic core using a flux measurement device, e.g., a Hall sensor. The output of the flux measurement device is processed to provide an indication of the primary current.

[0007] The geometry of the air gap, e.g., the distance and angle between two open ends of the magnetic core, directly affects the amount of magnetic flux received or detected by the flux measurement device, which affects the output of the flux measurement device, and thus the measurement result of the primary current.

[0008] In some application scenarios, the geometry of the air gap in a magnetic core may vary from time to time, which reduces the measurement accuracy. For example, a transducer with an OPEN / CLOSE type of magnetic core configuration may be vulnerable to variations in air gap geometry. Traditionally, to reduce the air gap geometry variation, a magnetic core of an OPEN / CLOSE configuration is typically designed to have very high rigidity and low deformation allowance, and a biasing element (e.g., a spring) that produces a strong biasing force toward the CLOSE configuration, which can be difficult and inconvenient to use.

[0009] BRIEF SUMMARY

[0010] A device according to the present disclosure includes a magnetic core having a first end surface, a second end surface, and a gap between the first and second end surfaces. A first cap structure is arranged adjacent to the first end surface. The first cap structure includes a material having a magnetic permeability higher than that of air, and the first cap structure includes a first protrusion portion that protrudes toward the second end surface of the magnetic core. A magnetic flux measurement device is positioned between the first protrusion portion and the second end surface of the magnetic core. The first cap structure is configured to concentrate the magnetic flux in the magnetic core onto a surface or surfaces of the first cap structure that are close to the second end surface or a surface of a second cap structure arranged on the second end surface of the magnetic core. The concentration of the magnetic flux helps that the measurement of the magnetic flux not impacted by the potential change in the geometry of the gap between the first and second end surfaces of the magnetic core.

[0011] These concepts and features, as well as other concepts and features, are exemplified by various embodiments of the techniques described herein.

[0012] BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0013] FIGS. 1A, 1B, 1C, 1 D show schematically example transducer systems according to at least one embodiment of the present disclosure.

[0014] FIGS. 2 and 3 show schematically cap structures arranged about an air gap of a magnetic code according to at least one embodiment of the present disclosure.

[0015] FIG. 4 shows schematically protrusion portions of the cap structures according to at least one embodiment of the present disclosure.

[0016] FIG. 5 schematically shows an alternative implementation of cap structures according to at least one embodiment of the present disclosure.

[0017] FIG. 6 shows a method of using a transducer system according to at least one embodiment of the present disclosure.

[0018] FIG. 7 shows a use environment of using a transducer system according to at least one embodiment of the present disclosure.

[0019] DETAILED DESCRIPTION

[0020] The disclosure provides techniques, device, and systems that compensate or eliminate the impact of the air gap geometry variation on measurement results of current measurement transducers.

[0021] A non-galvanic contact current measurement transducer is operative to detect a current value in a conductor without requiring galvanic contact with the conductor. The transducer may include a body and a flexible arm coupled to the body. The flexible arm movable between a closed position and an open position. In the closed position, the flexible arm and a portion of the body form a measurement loop that defines a measurement area that receives the insulated conductor and, in the open position, the flexible arm opens at least a portion of the measurement loop to allow the insulated conductor to move into and out of the measurement area. In some implementations, an actuator is operatively coupled to the flexible arm, which in operation, responsive to actuation by a user, moves the flexible arm from the closed position to the open position.

[0022] A magnetic core forms at least a portion of the flexible arm. In the closed position, the magnetic core includes at least one air gap. At least one non-contact sensor is coupled to at least one of the body or the flexible arm and is positioned in the at least one air gap and operative to measure magnetic flux going through the at least one air gap. In some implementations, a transducer system according to the present disclosure includes a flux concentrator that is arranged on one or more of the open ends of an air gap in the magnetic core, which concentrates or routes magnetic flux in the magnetic core to a designated path across the gap. The designated path can reduce fringing flux and reduce the impact of misalignment between the open ends of the magnetic core around the air gap. For example, the amount of magnetic flux flowing through the designated path will not vary or only vary to a lesser extent even if the geometry of the air gap changes.

[0023] For example, a flux concentrator may be a cap structure of a high magnetic permeability material that encapsulates an end surface of a magnetic core adjacent to the air gap. The cap structure includes a protrusion portion that protrudes into the air gap toward the other end surface of the magnetic core adjacent to the air gap. Magnetic flux in the magnetic core is conducted through the cap structure and concentrated into the protrusion structure to flow toward the other end surface of the magnetic core adjacent to the air gap. When the other end surface of the magnetic core includes a similar cap structure with a corresponding protrusion, the magnetic flux is concentrated by the protrusion structures as the magnetic flux flows across the air gap. Fringing flux is reduced or more easily controlled because the magnetic flux is concentrated into the designated path through the protrusion structure(s).

[0024] For example, in a case where the designated flux path includes two protrusion structures extending from two end surfaces of the magnetic code in the air gap, a first protrusion structure of the two protrusion structures includes a first protrusion surface larger, e.g., in an x-y plane, than a second protrusion surface of the second protrusion structure. Even if there is misalignment between the two end surfaces of the magnetic core forming the air gap, magnetic flux is still concentrated and directed to the smaller protrusion surface of the second protrusion structure, and with a measurement device properly positioned, e.g., positioned proximate to the second protrusion structure having a smaller protrusion surface, a great portion or all of the magnetic flux will be captured and measured by the measurement device.

[0025] For example, a measurement device that has a large detecting surface, e.g., larger than the surface area of the second protrusion surface of the second protrusion structure, is positioned proximate to the second protrusion surface and is able to detect a great portion or all of the magnetic flux flowing between the first and second protrusion structures even if there is misalignment between the first end surface and the second end surface of the magnetic core.

[0026] In some implementations as will be described herein, designated paths are configured such that the magnetic flux measured in the designated paths are complementary to one another. For example, the designated paths are arranged in a direction that the geometry of the air gap may vary. The variation of the geometry of the air gap in the direction will cause flux measurement in one of the designated paths to increase and the flux measurement in another one of the designated paths to decrease. However, the overall measurement results based on both flux measurements will not be impacted by the variation in air gap geometry because of the complementary nature of the two measurements. Such a complementary measurement arrangement can be implemented in any direction that the geometry of the air gap may vary. The flux concentrator enables the design and configuration of the complementary measurement of magnetic flux.

[0027] For example, in the designated flux paths, a first protrusion structure includes a first protrusion surface and a second protrusion surface opposite the first protrusion surface in a first direction. A second protrusion structure includes two end portions that together overlap or bracket the first protrusion structure in the first direction. Two measurement devices are used to detect the magnetic flux flowing between the first protrusion surface and the first end portion and the magnetic flux flowing between the second protrusion surface and the second end portion. The readings of the two measurement devices together account for the magnetic flux generated by the primary current. The misalignment between the first end surface and the second end surface in the first direction will not affect the overall flux detection reading because the readings of the two measurement devices are complementary to one another.

[0028] In some implementations, each of the first or second protrusion surface of the first protrusion structure may have a larger (or smaller) surface than the corresponding end portion of the second protrusion structure. As a result, the impact of misalignment between the end surfaces of the air gap in a second direction that is different from the first direction can also be reduced. For example, the first direction is a vertical direction, and the second direction is a lateral direction.

[0029] FIG. 1A shows schematically a transducer system 100. As shown in FIG. 1A, the transducer system 100 includes a magnetic core 110 having an air gap (first air gap) 112 between a first end surface 114 and a second end surface 116 adjacent to the air gap 112. A magnetic flux measurement device 120, e.g., a Hall sensor, is positioned in the air gap 112. The magnetic flux measurement device 120 is coupled to a measurement processing circuitry 122, illustratively shown as an amplifier.

[0030] Adjacent to each of the first end surface 114 and the second end surface 116 are a first cap structure 130 and a second cap structure 132, respectively. The cap structures 130, 132 are positioned between the first end surface 114 and the second end surface 116, and adjacent to the respective one of the first end surface 114 and the second end surface 116. The cap structures 130, 132 each includes a material having a magnetic permeability higher than that of air. In some implementations, the cap structures 130, 132 are made of a soft magnetic material, which are easily magnetized and demagnetized, and typically have intrinsic coercivity less than 1000 Am-1. For example, the cap structures 130, 132 are carbon steel having a magnetic permeability of 1.26X1 O’4H / m or nickel having a magnetic permeability of 1.26X1 O’4- 7.54X1 O’4 H / m. The cap structures 130, 132 may also be one or more of iron, silicon steel (e.g., in a case that the magnetic core 110 includes a plurality of laminated layers), iron- aluminum-silicon alloy, nickel-iron alloy, Iron-cobalt alloy, ferrites, and amorphous alloy. In some implementations, the materials of the cap structures 130, 132 have a higher magnetic permeability value than that of the magnetic core 110. For example, in a case the magnetic core 110 is iron having a magnetic permeability value of 6.3X1 O’3, the cap structures 130, 132 may be iron-cobalt having a magnetic permeability value of 2.3X10’2. In some implementations, the cap structures 130, 132 abut the respective end surfaces 114, 116. In some implementations, the cap structures 130, 132 do not abut the respective end surfaces 114, 116, but are positioned close to the respective end surfaces 114, 116 so that fringing flux is reduced between the cap structures 130, 132 and the respective end surfaces 114, 116.

[0031] In operation, the current to be measured, referred to as primary current lp, flows through a conductor 140 that passes through an area 111 (referred to as a “measurement area”) encircled by the magnetic core 110 that functions as a measurement loop. The primary current lpgenerates a magnetic field inside the magnetic core 110. The magnetic core 110 has a magnetic permeability much higher than air such that it confines and guides the magnetic field produced by the primary current lpto follow the path of the magnetic code 110 as magnetic flux. The cap structures further confine and guide the magnetic flux in the air gap 112, the density of which is measured by the magnetic flux measurement device 120. For example, in a case where the magnetic flux measurement device 120 is a Hall sensor, its output is a voltage proportional to the magnetic flux, which is also proportional to the primary current lp. As such, assuming that the magnetic flux in the magnetic core 110 is not saturated, which indicates an upper limit of the primary current lpto be measured, by processing the outputs of the magnetic flux measurement device 120, by the measurement processing circuitry 122, the value of the primary current lpcan be obtained.

[0032] In some implementations, the magnetic core 110 may include a body 113 and a flexible arm 115 coupled to the body. The flexible arm 115 is configured to move between a closed position and an open position. In the closed position, shown in FIG. 1 A, the flexible arm 115 and the body 113 form a measurement loop of the magnetic core 110 that defines the measurement area 111 , which is configured to receive the conductor 140 for measurement. In the open position (not specifically shown in FIG. 1 A), the flexible arm 115 opens at least a portion of the measurement loop to allow the conductor 140 to move into and out of the measurement area. In some implementations, an actuator (not shown in FIG. 1A for brevity) is operatively coupled to the flexible arm 115, which in operation, e.g., responsive to actuation by a user, moves the flexible arm 115 to transit between the closed position and the open position. The first end surface 114 and the second end surface 116 may be positioned both in the body 113, both in the flexible arm 115, or may be positioned in the body 113 and the flexible arm 115, respectively, which do not limit the scope of the disclosure and are all included in the scope of the disclosure. The movement of the flexible arm 115 between the open position and the closed position may cause some variation in the geometry of the air gap 112 between the first and second end surfaces 114, 116.

[0033] In some implementations, the flexible arm 115 is coupled to the body 113 via a hinge that allows the flexible arm to switch between a closed position and an open position. In some implementations, the flexible arm 115 is coupled to the body 113 in a rotatable manner. Rotation of the flexible arm 115 will move it between a closed position and an open position with respect to the body 113, given the curved profile of the flexible arm. In some implementations, the flexible arm 115 is configured to slide with respect to the body 113 in the transition between a closed position and an open position.

[0034] It should be noted that although the measurement processing circuitry 122 is shown simply as an open loop circuitry, it does not limit the scope of the disclosure. In some implementations, the measurement processing circuitry 122 may include a feedback path, which sends a feedback signal to adjust a current through a secondary winding (not shown for simplicity) around the magnetic core 110.

[0035] FIG. 1B shows schematically a section view of some embodiment of the magnetic core 110 and the cap structures 130, 132. Referring to FIGS 1A and 1B together, in some implementations, cap structures 130, 132 are arranged adjacent to respective end surfaces 114, 116 about the air gap 112 of the magnetic core 110. In some implementations, one or more of the cap structures 130, 132 include extension portions 134, 136 that extend around the adjacent portion of the magnetic core 110 from the respective end surfaces 114, 116. As such, the cap structures 130, 132 fully encapsulate the respective end surfaces 114, 116. The extension portions 134, 136 further help to concentrate magnetic flux to the cap structures 130, 132 so that the magnetic flux goes through the cap structures 130, 132.

[0036] In some implementations, one or more of the cap structures 130, 132 include a relatively flush surface 150, 152, respectively. The relatively flush surfaces 150, 152 help to stabilize the magnetic flux flowing between the end surfaces 114 and 116.

[0037] As shown in FIG. 1B, in some implementations, the magnetic core 110 is a laminate core having a plurality of thin magnetic layers or sheets of iron or other materials of high magnetic permeability stacked over one another, each arranged along or in parallel with lines of magnetic flux. Insulating layers 212 of low magnetic permeability, e.g., copper or bismuth, are positioned between two adjacent magnetic layers 210. Further, it should be noted that although FIG. 1A shows the magnetic flux measurement device 120 positioned in the air gap 112, this example implementation does not limit the scope of the disclosure, other measurement devices, e.g., a tunneling magneto resistive (TMR) sensor 160 shown in FIG. 1C, may be used to measure the magnetic flux, and may be positioned in other suitable places than in the air gap 112. The magnetic flux in the core 110 may change the orientation of the magnetic field in the free magnetic layer of the TMR sensor, which causes the tunneling current to change. The tunnel current may be detected and analyzed by a microcontroller 162 coupled to the TMR 160 to determine the magnetic flux in the magnetic core 110.

[0038] In another example, as shown in FIG. 1 D, the magnetic flux in the magnetic core 110 may be measured by a fluxmeter 172. The magnetic core 110 is placed in the center of a coil 170 connected to the fluxmeter 172 for the flux meter 172 to detect the density of magnetic flux in the magnetic core 110.

[0039] The measurement of the magnetic flux by other types of measurement devices not positioned in the air gap 112, e.g., shown in FIGS. IC and 1D, may still benefit from the implementations of the cap structures 130, 132, because the magnetic flux flowing through the air gap 112 is stabilized by the cap structures 130, 132.

[0040] FIG. 2 shows schematically a sectional view of a portion of the magnetic core 110 about the air gap 112 according to at least one implementation of the present disclosure. As shown in FIG. 2, in some implementations, the magnetic core 110 is a laminate core having a plurality of thin magnetic layers or sheets of iron or other materials of high magnetic permeability stacked over one another, each arranged along or in parallel with lines of magnetic flux. Insulating layers 212 of low magnetic permeability, e.g., copper or bismuth, are positioned between two adjacent magnetic layers 210.

[0041] Cap structures 230, 232 are arranged adjacent to respective end surfaces 114, 116 about the air gap 112. In some implementations, one or more of the cap structures 230, 232 include extension portions 234, 236 that extend around the adjacent portion of the magnetic core 110 from the respective end surfaces 114, 116. As such, the cap structures 230, 232 encapsulate the respective end surfaces 114, 116. The extension portions 234, 236 further help to concentrate magnetic flux to the cap structures 230, 232 so that the magnetic flux goes through the cap structures 230, 232.

[0042] In some implementations, one or more of the cap structures 230, 232 includes a protrusion portion 240, 242, respectively. Each of the protrusion portions 240, 242 protrudes from the adjacent end surfaces 114, 116 toward the opposite end surfaces 116, 114. For example, protrusion portion 240 protrudes into the air gap 112 from the adjacent end surface 114 toward the opposite end surface 116. Protrusion portion 242 protrudes into the air gap 112 from the adjacent end surface 116 toward the opposite end surface 114.

[0043] The protrusion portions 240, 242 each includes a protrusion surface 244, 246 that faces the opposite end surfaces 116, 114. In some implementations, one or more of the protrusion surfaces 244, 246 are smaller in area than the respective opposite end surfaces 116, 114. In some implementations, the protrusion surfaces 244, 246 face one another, e.g., in the x-axis direction, and one of the protrusion surfaces, e.g., protrusion surface 246, has a smaller surface area than the other protrusion surface, e.g., protrusion surface 244. The smaller surface area of the protrusion surface 246 ensures that even if the relative positions between the end surfaces 114, 116 vary, the protrusion surface 246 still completely projects onto the larger surface area of the protrusion surface 244 so that the magnetic flux between the protrusion surfaces 244, 246 will not vary.

[0044] In some implementations, the magnetic flux measurement device 120 is positioned between the two protrusion surfaces 244, 246, and in proximity to the protrusion surface 246 that has the smaller surface area among the two protrusion surfaces 244, 246. In some implementations, the magnetic flux measurement device 120 has a detection surface 250 that is larger than the surface area of the protrusion surface 246. A projection of the protrusion surface 246 on the detection surface 250 is completely within the detection surface 250 in the y-z plane. For example, the magnetic flux measurement device 120 includes a detection surface that extends beyond the protrusion surface 246 in any direction orthogonal to the x-axis direction along which the protrusion surfaces 244, 246 face one another. As such, even if the relative positions between the end surfaces 114, 116 vary, the large detection surface 250 still enables the magnetic flux measurement device 120 to detect all the magnetic flux between the protrusion surfaces 244, 246.

[0045] In some implementations the protrusion surfaces 244 and 246 are similar in areas and the detection surface 250 is larger than the surface area of the each of the protrusion surfaces 244 and 246. As such, even if the relative positions between the end surfaces 114, 116 vary, the large detection surface 250 still enables the magnetic flux measurement device 120 to detect the magnetic flux between the protrusion surfaces 244, 246.

[0046] In some implementations, the protrusion surfaces 244 and 246 are both smaller in area than the end surfaces 114, 116. Taking advantage of the cap structures 230, 232, the magnetic flux is concentrated to the smaller surface area of the protrusion surfaces 244, 246, which facilitates the measurement of the magnetic flux, and stabilizes the magnetic flux, e.g., by reducing fringing flux.

[0047] The cap structures 230, 232 are preferably comprised of iron, steel, nickel, or other material that has a magnetic permeability higher than that of air.

[0048] In operation, because the cap structures 230, 232 have higher magnetic permeability than air, the magnetic flux in the magnetic core 110 is confined and guided to go through the cap structures 230, 232, and a second, smaller air gap 252 between the protrusion surfaces 244, 246 of the cap structures 230, 232. With the proper configurations of the protrusion surfaces 244, 246, e.g., the protrusion surface 246 being smaller in area than the protrusion surface 244 and being completely projected within the protrusion surface 244 in the y-z plane, the density of magnetic flux going through the second air gap 252 will not vary, or at least vary much less, with variation in the relative positions of the end surfaces 114, 116.

[0049] FIG. 3 shows schematically a sectional view of a portion of the magnetic core 110 about the air gap 112 according to another implementation of the present disclosure. As shown in FIG. 3, cap structures 330, 332 include respective protrusion portions 340, 342. The protrusion portion 342 includes a first end portion 362 and a second end portion 364 spaced apart from one another in the y-axis direction. The protrusion portion 340 is positioned between the first end portion 362 and the second end portion 364 in the y-axis direction. For example, a first surface 366 of the protrusion portion 340 faces and at least partially overlaps with the first end portion 362 of the protrusion portion 342, while a second opposite surface 368 of the protrusion portion 340 faces and at least partially overlaps with the second end portion 364 of the protrusion portion 342. A third air gap 352 exists between the surface 366 of the protrusion portion 340 and the first end portion 362 of the protrusion portion 342. A fourth air gap 354 exists between the surface 368 of the protrusion portion 340 and the second end portion 364 of the protrusion portion 342.

[0050] A first magnetic flux measurement device 320 is positioned to measure magnetic flux density in the third air gap 352. A second magnetic flux measurement device 322 is positioned to measure magnetic flux density in the fourth air gap 354. In some implementations, magnetic flux measurement devices 320, 322 are positioned in proximity to the respective end portions 362, 364, respectively.

[0051] In operation, magnetic flux in the magnetic core 110 is confined and guided to the cap structures 330, 332, and goes through the third air gap 352 and the fourth air gap 354. The magnetic flux density in the third air gap 352 and the fourth air gap 354 together reflects the magnetic flux density in the magnetic core 110. In case the relative positions of end surfaces 114, 116 of the magnetic core 110 vary in the y-axis direction, the dimensions of the third air gap 352 and the fourth air gap 354 will change in a complementary manner. For example, when a distance in y-axis between the surface 366 of the protrusion portion 340 and the first end portion 362 of the protrusion portion 342 decreases, a distance in y-axis between the surface 368 of the protrusion portion 340 and the second end portion 364 of the protrusion portion 342 increases. When the distance in y-axis between the surface 366 of the protrusion portion 340 and the first end portion 362 of the protrusion portion 342 increases, the distance in y-axis between the surface 368 of the protrusion portion 340 and the second end portion 364 of the protrusion portion 342 decreases.

[0052] The variations in the air gaps 352, 354 cause variations in the magnetic flux density in the air gaps 352, 354. However, due to the complementary nature of the variations in the air gaps 352, 354, the overall or combined density of magnetic flux detected by the magnetic flux measurement devices 320, 322 will not change and still accurately reflect the magnetic flux in the magnetic core 110. In various implementations, the cap structures 330, 332 can be configured so that the protrusion portion 340 is bracketed by the end portions 362, 364 in a direction that the relative portions of end surfaces 114, 116 may vary. The complementary measurements of the magnetic flux density in the air gaps 352, 354 will generate an overall combined measurement result that is not affected by the variation between end surfaces 114, 116.

[0053] FIG. 3 illustratively shows that the protrusion portion 340 is bracketed by the end portions 362, 364 in the y-axis direction, which does not limit the scope of the disclosure. In implementations, the protrusion portion 340 can be bracketed by the end portions 362, 364 in any direction that end surfaces 114, 116 supposes to vary their relative positions. Further, the protrusion portion 340 can be bracketed by the end portions of the protrusion portion 342 in more than one direction, e.g., in both the y-axis direction and the z-axis direction.

[0054] FIG. 4 shows that the protrusion portion 340 is bracketed by the end portions 362, 364 of the protrusion portion 342 in a first direction, and is bracketed by end portions 370, 372 of the protrusion portion 342 in a second direction that is different from the first direction. Four magnetic flux measurement devices 120 are arranged to measure the magnetic flux density in the air gaps between the protrusion portion 340 and each of the end portions 362, 364, 370, 372. Variations in the relative positions between end surfaces 114, 116 in the first direction and in the second direction can be compensated by the complementary measuring configuration shown in FIG. 4.

[0055] Referring back to FIGS. 2-4, the cap structures, having the magnetic permeability higher than that of air, effectively concentrate magnetic flux to a surface or surfaces that are close to a surface of a cap structure arranged on the opposite end surface of the magnetic core. Magnetic flux will go through the air gap(s) between those surfaces (referred to as “flux concentration surface” for descriptive purposes) of concentrated magnetic flux. For example, protrusion surfaces 244, 246, 366, 368 are flux concentration surfaces. The end portions 362, 364 each includes a flux concentration surface that faces the flux concentration surfaces 366, 368, respectively.

[0056] The flux concentration surfaces enable the air gaps for magnetic flux measurement to be configured in a way that is different from the air gap between the end surfaces 114, 116. For example, FIG. 3 shows that the end surfaces 114, 116 face one another in the x-axis direction, while for the air gaps 352, 354, the respective concentration surfaces face one another in the y-axis direction so that variations in y- axis direction in the relative positions between the end surfaces 114, 116 can be accommodated or compensated. As such, the geometry variation of the air gap 112 will not affect the measurement of magnetic flux generated by the primary current lp.

[0057] The flux concentration surfaces can be arranged or configured based on the need to accommodate or compensate for the possible geometry variation in the air gap 112 between end surfaces 114, 116. For example, FIG. 5 shows an alternative implementation where flux concentration surfaces 502, 504 are arranged to face one another in the y-axis direction instead of in the x-axis direction as in the example shown in FIG. 2.

[0058] FIG. 6 shows an example implementation of a method for measuring a current in a conductor using a non-galvanic contact current measurement transducer. The non- galvanic contact current measurement transducer includes a magnetic core 110, e.g., as shown in FIGS. 1-5. The magnetic core 110 may include a body and a measurement end, coupled to the body. The measurement end includes a moveable arm(s), e.g., a flexible arm, a clamp, or a jaw, that is movable between a closed position and an open position. In the closed position, the measurement end and a portion of the body form a measurement loop of the magnetic core 110 that surrounds or defines a measurement area that receives the conductor 140 and, in the open position, the measurement end opens at least a portion of the measurement loop to allow the conductor to move into and out of the measurement area.

[0059] In operation 602, a conductor is received into a measurement area of a transducer.

[0060] Specifically, in operation 610, a user operates the transducer to move the moveable arm to the open position. For example, the user may operate an actuator to move the moveable arm from the closed position to the open position. In the open position, at least a portion of the measurement loop of the magnetic core 110 is opened.

[0061] In operation 620, a conductor 140 is received in the measurement area.

[0062] In operation 630, the user operates the actuator of the transducer to move the moveable arm to the closed position, with the conductor 140 remaining in the measurement area.

[0063] Measurement of the primary current lPflowing through the conductor 140 can then be performed in operation 604, using, e.g., the magnetic flux measurement device 112 and the measurement processing circuitry 122.

[0064] FIG. 7 is a pictorial diagram of an environment 700 in which a transducer device 702 may be used by a user 704 to measure a current present in a conductor 706, e.g., using the method shown in FIG. 6, without requiring galvanic contact between the transducer device 702 and the conductor 706. The transducer device 702 may include some or all of the features of the magnetic core 110 discussed herein with reference to FIGS. 1-5. In some implementations, the transducer device 702 includes a housing or body 708 which includes a grip portion 710 and a probe portion or measurement end 712, opposite the grip portion 710. The housing 708 may also include a user interface 714 which facilitates user interaction with the transducer device 702. The user interface 714 may include any number of inputs (e.g., buttons, dials, switches, touch sensor) and any number of outputs (e.g., display, LEDs, speakers, buzzers). The transducer device 702 may also include one or more wired and / or wireless communications interfaces (e.g., USB, Wi-Fi®, Bluetooth®). In at least some implementations, the probe portion 712 may include a measurement loop 716 that defines a measurement area 718 configured to receive the conductor 706. The measurement loop 716 includes a moveable arm 720 that is configured to switch between an open position and a closed position (the closed portion shown in FIG. 7) so that the conductor 706 can be received within the measurement area 718.

[0065] The measurement loop 716 may include the magnetic core 100 embedded therein. The measurement processing circuit 122 may be embedded in the body 708 or may be partially in the body 708 and partially in a remote processing device that communicatively coupled to the transducer device 702.

[0066] For the purposes of the present disclosure, unless otherwise indicated, the phrase “A and B” is nonlimiting and means one or more of (A) and one or more of (B); the phrase “A or B” is nonexclusive and means one or more of (A), one or more of (B), or one or more of (A and B); the phrase “A and / or B” means one or more of (A), one or more of (B), or one or more of (A and B); the phrase “at least one of A and B” and the phrase “one or more of A and B” both mean one or more of (A) and one or more of (B); and the phrase “at least one of A or B” and the phrase “one or more of A or B” both mean one or more of (A), one or more of (B), or one or more of (A and B). By way of extension, for example, the phrases “at least one of A, B, or C” and “one or more of A, B, or C” both mean one or more of (A), one or more of (B), one or more of (C), one or more of (A and B), one or more of (A and C), one or more of (B and C), or one or more of (A, B and C). In the above, A, B, and C represent any form or type of element, feature, arrangement, component, structure, aspect, action, step, etc.

[0067] These and other changes can be made to the embodiments in light of the above-detailed description. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled. Accordingly, the claims are not limited by the disclosure.

[0068] Described embodiments of the subject matter can include one or more examples, alone or in combination.

[0069] An example transducer system includes a magnetic core having a first end surface, a second end surface, and a gap between the first and second end surfaces. The example transducer system also includes a first cap structure arranged adjacent to the first end surface, the first cap structure including a material having a magnetic permeability higher than that of air.

[0070] The example optionally specifies that the first cap structure includes a first protrusion portion that protrudes toward the second end surface.

[0071] The example optionally also includes a magnetic flux measurement device positioned between the first protrusion portion and the second end surface. The example optionally specifies that the first protrusion portion includes a first protrusion surface facing the second end surface, and wherein the first protrusion surface is smaller in area than the second end surface.

[0072] The example optionally also includes a second cap structure arranged adjacent to the second end surface, the second cap structure including a material having a magnetic permeability higher than that of air, the second cap structure including a second protrusion portion that protrudes toward the first end surface.

[0073] The example optionally specifies that the first protrusion portion includes a first protrusion surface, the second protrusion portion includes a second protrusion surface facing the first protrusion surface in a first direction, and the first protrusion surface is smaller in area than the second protrusion surface.

[0074] The example optionally specifies that the magnetic flux measurement device is positioned proximate to the first protrusion surface.

[0075] The example optionally specifies that the magnetic flux measurement device includes a detection surface that extends beyond the first protrusion surface in any direction orthogonal to the first direction.

[0076] The example optionally specifies that the second protrusion portion includes a first end portion and a second end portion, the first protrusion portion positioned between the first and second end portions in a first direction, and the first protrusion portion at least partially overlapping the first and second end portions in the first direction.

[0077] The example optionally specifies that the magnetic flux measurement device includes a first measurement element and a second measurement element, the first measurement element positioned between the first protrusion portion and the first end portion, and the second measurement element positioned between the first protrusion portion and the second end portion.

[0078] The example optionally specifies that the first cap structure includes an extending portion that extends around the magnetic core and from the first end surface.

[0079] The example optionally specifies that the first cap structure encapsulates the first end surface.

[0080] The example optionally specifies that the magnetic permeability of the material of the first gap structure is higher than a magnetic permeability of the magnetic core.

[0081] The example optionally specifies that the material of the first gap structure is a soft magnetic material.

[0082] The example optionally specifies that the magnetic core includes a plurality of magnetic layers stacked over one another and a plurality of insulating layers each positioned between two magnetic layers of the plurality of magnetic layers.

[0083] An example device includes a magnetic core having a first end surface and a second end surface separated from one another; a first cap structure arranged adjacent to the first end surface, the first cap structure including a material having a magnetic permeability higher than that of air, the first cap structure including a first flux concentration surface and a second flux concentration surface; and a second cap structure arranged adjacent to the second end surface, the second cap structure including a material having a magnetic permeability higher than that of air, the second cap structure including a third flux concentration surface and a fourth flux concentration surface, the first flux concentration surface facing and at least partially overlapping the third flux concentration surface, and the second flux concentration surface facing and at least partially overlapping the fourth flux concentration surface.

[0084] The example optionally also includes a first magnetic flux measurement device positioned between the first flux concentration surface and the third flux concentration surface, and a second magnetic flux measurement device positioned between the second flux concentration surface and the fourth flux concentration surface.

[0085] The example optionally specifies that the first flux concentration surface faces the third flux concentration surface in a first direction, and the second flux concentration surface faces the fourth flux concentration surface in the first direction.

[0086] The example optionally specifies that the first end surface and the second end surface face one another in a second direction different from the first direction.

[0087] The example optionally specifies that the first flux concentration surface and the second flux concentration surface are opposite to one another in a first direction, and the third flux concentration surface and the fourth flux concentration surface together bracket the first flux concentration surface and the second flux concentration surface in the first direction.

[0088] The example optionally specifies that the first cap structure further includes a fifth flux concentration surface and a sixth flux concentration surface opposite to one another in a second direction different from the first direction; in the second cap structure further includes a seventh flux concentration surface and an eighth flux concentration surface, the fifth flux concentration surface facing and at least partially overlapping the seventh flux concentration surface, and the sixth flux concentration surface facing and at least partially overlapping the eighth flux concentration surface; and the device further comprises a third magnetic flux measurement device positioned between the fifth flux concentration surface and the seventh flux concentration surface, and a fourth magnetic flux measurement device positioned between the sixth flux concentration surface and the eighth flux concentration surface.

[0089] An example method includes receiving a conductor into a measurement area of a transducer by opening a moveable arm of the transducer. The transducer includes: a magnetic core having a first end surface, a second end surface, and a gap between the first and second end surfaces; a first cap structure arranged adjacent to the first end surface, the first cap structure including a material having a magnetic permeability higher than that of air. The example method also includes forming a measurement loop around the measurement area by closing the moveable arm, and measuring a current flowing through the conductor using a magnetic flux measurement device coupled to the magnetic core and a measurement processing circuit coupled to the magnetic flux measurement device.

[0090] The example optionally specifies that the measuring the current flowing through the conductor includes measuring a magnetic flux flowing between the first end surface and the second end surface using the magnetic flux measurement device positioned in the gap between the first end surface and the second end surface.

[0091] It should be appreciated that the various embodiments described above can be combined to provide yet further embodiments of the transducer system 100. Aspects of the embodiments can be modified, and other changes can be made to the embodiments in light of the above-detailed description, without departing from the spirit or scope of the disclosure.

Claims

CLAIMS1 . A transducer system, comprising: a magnetic core having a first end surface, a second end surface, and a gap between the first and second end surfaces; and a first cap structure arranged adjacent to the first end surface, the first cap structure including a material having a magnetic permeability higher than that of air.

2. The transducer system of claim 1 , wherein the first cap structure includes a first protrusion portion that protrudes toward the second end surface.

3. The transducer system of claim 2, comprising a magnetic flux measurement device positioned between the first protrusion portion and the second end surface.

4. The transducer system of claim 2 or claim 3, wherein the first protrusion portion includes a first protrusion surface facing the second end surface, and wherein the first protrusion surface is smaller in area than the second end surface.

5. The transducer system of claim 3, further comprising a second cap structure arranged adjacent to the second end surface, the second cap structure including a material having a magnetic permeability higher than that of air, the second cap structure including a second protrusion portion that protrudes toward the first end surface.

6. The transducer system of claim 5, wherein the first protrusion portion includes a first protrusion surface, the second protrusion portion includes a second protrusion surface facing the first protrusion surface in a first direction, and the first protrusion surface is smaller in area than the second protrusion surface.

7. The transducer system of claim 6, wherein the magnetic flux measurement device is positioned proximate to the first protrusion surface, or wherein the magnetic flux measurement device includes a detection surface that extends beyond the first protrusion surface in any direction orthogonal to the first direction.

8. The transducer system of any one of claims 5 to 7, wherein the second protrusion portion includes a first end portion and a second end portion, the firstprotrusion portion positioned between the first and second end portions in a first direction, and the first protrusion portion at least partially overlapping the first and second end portions in the first direction, and optionally wherein the magnetic flux measurement device includes a first measurement element and a second measurement element, the first measurement element positioned between the first protrusion portion and the first end portion, and the second measurement element positioned between the first protrusion portion and the second end portion.

9. The transducer system of claim 1 , wherein the first cap structure includes an extending portion that extends around the magnetic core and from the first end surface or wherein the first cap structure encapsulates the first end surface, or wherein the magnetic permeability of the material of the first cap structure is higher than a magnetic permeability of the magnetic core, or wherein the material of the first cap structure is a soft magnetic material, or wherein the magnetic core includes a plurality of magnetic layers stacked over one another and a plurality of insulating layers each positioned between two magnetic layers of the plurality of magnetic layers.

10. The transducer system of claim 1 , wherein the first cap structure includes a first flux concentration surface and a second flux concentration surface; the transducer system further comprising a second cap structure arranged adjacent to the second end surface, the second cap structure including a material having a magnetic permeability higher than that of air, the second cap structure including a third flux concentration surface and a fourth flux concentration surface, the first flux concentration surface facing and at least partially overlapping the third flux concentration surface, and the second flux concentration surface facing and at least partially overlapping the fourth flux concentration surface.11 . The transducer system of claim 10, further comprising a first magnetic flux measurement device positioned between the first flux concentration surface and the third flux concentration surface, and a second magnetic flux measurement device positioned between the second flux concentration surface and the fourth flux concentration surface.

12. The transducer system of claim 10 or claim 11 , wherein the first flux concentration surface faces the third flux concentration surface in a first direction, andthe second flux concentration surface faces the fourth flux concentration surface in the first direction, and optionally wherein the first end surface and the second end surface face one another in a second direction different from the first direction.

13. The transducer system of claim 11 , wherein the first flux concentration surface and the second flux concentration surface are opposite to one another in a first direction, and wherein the third flux concentration surface and the fourth flux concentration surface together bracket the first flux concentration surface and the second flux concentration surface in the first direction, and optionally wherein: the first cap structure further includes a fifth flux concentration surface and a sixth flux concentration surface opposite to one another in a second direction different from the first direction; the second cap structure further includes a seventh flux concentration surface and an eighth flux concentration surface, the fifth flux concentration surface facing and at least partially overlapping the seventh flux concentration surface, and the sixth flux concentration surface facing and at least partially overlapping the eighth flux concentration surface; and the transducer system further comprises a third magnetic flux measurement device positioned between the fifth flux concentration surface and the seventh flux concentration surface, and a fourth magnetic flux measurement device positioned between the sixth flux concentration surface and the eighth flux concentration surface.

14. A method, comprising: receiving a conductor into a measurement area of a transducer by opening a moveable arm of the transducer, the transducer including: a magnetic core having a first end surface, a second end surface, and a gap between the first and second end surfaces; and a first cap structure arranged adjacent to the first end surface, the first cap structure including a material having a magnetic permeability higher than that of air; forming a measurement loop around the measurement area by closing the moveable arm; and measuring a current flowing through the conductor using a magnetic flux measurement device coupled to the magnetic core and a measurement processing circuit coupled to the magnetic flux measurement device.

15. The method of claim 14, wherein the measuring the current flowing through the conductor includes measuring a magnetic flux flowing between the first end surface and the second end surface using the magnetic flux measurement device positioned in the gap between the first end surface and the second end surface.

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