Current Sensor

Abstract

To provide a dual-channel current sensor.SOLUTION: A dual-channel current sensor includes a housing, a core, and a printed circuit board assembly (PCBA). The housing has a cylindrical cavity and an end portion, where the cylindrical cavity is open at a first end. The core is cylindrical in shape with flattened top and bottom surfaces and has a flat zone on an interior surface, a gap perpendicular and opposite the flat zone, a first portion adjacent one side of the gap, and a second portion adjacent the other, opposite side of the gap. The core is inserted into first end of the cylindrical cavity. The PCBA inserted into the end portion of the housing has a sensor disposed in the gap.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE Embodiments of the present disclosure relate to current sensors, and more particularly, to current sensors for use in electronic vehicle systems. [Background technology]

[0002] Current sensors detect electrical current flowing through a carrying conductor, such as a wire or cable. Electronic vehicle (EV) systems, such as battery charger systems, battery systems, power distributor systems, inverter systems, and converter systems, may employ current sensors.

[0003] A Hall effect current sensor consists of an open-loop magnetic core and a Hall sensor, which is a magnetically sensitive semiconductor device. The Hall sensor is placed in the gap of the core. A carrying conductor, such as a cable, is threaded through the loop of the core. When a current passes through the conductor, a magnetic field is generated in the core. When the Hall sensor is exposed to the magnetic field from the core, a small Hall voltage is generated. The Hall voltage is proportional to the product of the current in the conductor and the magnetic field, which is proportional to the surface area of the sensor. The Hall sensor is capable of detecting currents within a small current range.

[0004] The shape of the magnetic core can affect its saturation point and the linearity of the Hall sensor output. If the magnetic core is a wound core, the shape it can have is limited, which limits both of these characteristics. If two cores are replaced with a PCBA with their respective hollow rings, the electronic components on the PCBA will be destroyed during ultrasonic welding. Furthermore, the manufacturing efficiency of double-sided welding for the core is low.

[0005] It is with respect to these and other considerations that the present improvements may be useful. Summary of the Invention

[0006] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to aid in determining the scope of the claimed subject matter.

[0007] An exemplary embodiment of a dual-channel current sensor according to the present disclosure may include a housing, a core, and a printed circuit board assembly (PCBA). The housing has a cylindrical cavity and an end, where the cylindrical cavity is open at a first end. The core is cylindrical in shape with flat top and bottom surfaces, a flat area on an inner surface, a gap perpendicular to and facing the flat area, a first portion adjacent to one side of the gap, and a second portion adjacent to the other opposite side of the gap. The core is inserted into the first end of the cylindrical cavity. A PCBA inserted into the end of the housing has a sensor disposed in the gap. [Brief explanation of the drawings]

[0008] [Figure 1A] FIG. 1 illustrates a dual-channel current sensor according to an exemplary embodiment. [Figure 1B] FIG. 1 illustrates a dual-channel current sensor according to an exemplary embodiment. [Figure 1C] FIG. 1 illustrates a dual-channel current sensor according to an exemplary embodiment. [Figure 1D] FIG. 1 illustrates a dual-channel current sensor according to an exemplary embodiment.

[0009] [Figure 2A] FIG. 1 illustrates a dual-channel current sensor with a wound core according to an exemplary embodiment. [Figure 2B] FIG. 1 illustrates a dual-channel current sensor with a wound core according to an exemplary embodiment.

[0010] [Figure 3A] FIG. 1 illustrates a dual channel current sensor with a stamped core according to an exemplary embodiment. [Figure 3B] FIG. 1 illustrates a dual channel current sensor with a stamped core according to an exemplary embodiment.

[0011] [Figure 4A] FIG. 4 illustrates the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment. [Figure 4B] FIG. 4 illustrates the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment. [Figure 4C] FIG. 4 illustrates the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment. [Figure 4D] FIG. 4 illustrates the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment.

[0012] [Figure 5] 3C is a graph illustrating the operation of Hall sensors in the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment.

[0013] [Figure 6] 3C is a graph illustrating the operation of Hall sensors in the dual-channel current sensor of FIGS. 3A-3B, according to an exemplary embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] The dual-channel sensor consists of two cores, one larger than the other, separated by a spacer inserted into a housing. The two cores are cylindrical, each with a flat top and sides and each with a gap. The housing has ends and a cylindrical cavity that is open at one end. The smaller-diameter core is inserted into the housing first, followed by the spacer, and then finally the larger-diameter core. A printed circuit board assembly (PCBA) with two sensors is inserted into the ends of the housing so that the first sensor occupies the gap in the larger-diameter core, while the second sensor occupies the gap in the smaller-diameter core. The larger-diameter core can be stamped to have a flat area that fits into the cylindrical cavity with a similar flat area. The larger-diameter core also has two sections on either side of the gap that are shorter in height than the rest of the core. The ends of the housing have rigid locating features to hold the PCBA during insertion of the press-fit pins.

[0015] For convenience and clarity, terms such as "top," "bottom," "up," "down," "vertical," "horizontal," "lateral," "transverse," "radial," "inner," "outer," "left," and "right" may be used herein to describe the relative location and orientation of features and components with respect to the geometry and orientation of other features and components appearing in the perspective, exploded perspective, and cross-sectional views, respectively, provided herein. Such terms are not intended to be limiting and include the specifically mentioned words, derivatives thereof, and words of similar import.

[0016] 1A-1D are representative diagrams of a dual channel current sensor 100 for providing current sensing, according to an exemplary embodiment. FIG. 1A is an overhead view of the dual channel current sensor 100, FIGS. 1B-1C are perspective views, and FIG. 1D is an exploded perspective view. The dual channel current sensor 100 features two cores, a first core 106 and a second core 110, separated by a spacer 108.

[0017] In the exemplary embodiment, the first core 106 and the second core 110 are similar to each other because they both have approximately the same diameter and circumference, with the first core 106 being taller than the second core 110. The first core 106 may therefore be considered a large-diameter core, while the second core 110 is a small-diameter core. Both cores 106 and 110 are substantially cylindrical or torus-shaped, with substantially flat top and bottom surfaces and rounded outer and inner surfaces, except that in the exemplary embodiment, core 106 has a flat portion on its inner surface. Both cores 106 and 110 are open cores because they each have a gap to accommodate a separate sensor. Both cores 106 and 110 have a hollow center to receive a carrier conductor, such that the carrier conductor is substantially perpendicular to the core.

[0018] The dual-channel current sensor 100 features a housing 102 having a cylindrical cavity 112 and an end 132. The cylindrical cavity 112 is a hollow ring open at one end to receive the first core 106 and the second core 110. In contrast to some prior art sensor housings, the cylindrical cavity 112 is not open at the bottom. Thus, the first core 106, the spacer 108, and the second core 110 fit into the cylindrical cavity 112, with an arrow 120 indicating the assembly direction: the second core 110 is inserted into the hollow cylindrical cavity 112, followed by the spacer 108, and then the first core 106. In the exemplary embodiment, the spacer 108 ensures some distance between the cores 106 and 110. A top cover 104 is positioned over the top opening of the cylindrical cavity 112, adjacent to the first core 106, to close the housing 102. In the exemplary embodiment, top cover 104 is attached to the top of cylindrical cavity 112 of housing 102 and is pressed against core 106, spacer 108, and core 110 using ultrasonic welding.

[0019] End 132 of housing 102 includes an electrical connector receptacle 126 for connecting dual channel current sensor 100 to a power source. End 132 further receives a printed circuit board assembly (PCBA) 114. Once fully inserted, PCBA 114 spans between end 132 and the cylindrical cavity 112 of housing 102. In addition to other electronic components, PCBA 114 includes a first sensing application specific integrated circuit (ASIC) 122 and a second sensing ASIC 124. As shown in FIG. 1D , ASIC 122 is orthogonal to ASIC 124. In a non-limiting embodiment, ASIC 122 and ASIC 124 are Hall sensors.

[0020] Arrow 118 indicates the assembly direction of PCBA 114: the side features of ASICs 122 and 124 of PCBA 114 are inserted first, then the PCBA is seated in cylindrical cavity 112 until it partially occupies it ( FIG. 1A ), and then side cover 116 is placed over end 132. In an exemplary embodiment, side cover 116 is attached by laser welding or another process such as epoxy potting. Side cover 116 thus seals PCBA 114 to the interior of housing 102.

[0021] In some prior art implementations, the PCBA is inserted into the same opening in the housing that receives the core. The PCBA is inserted into the opening, and then the core is inserted through the PCBA. During ultrasonic welding of the core, the electronic components of the PCBA may be damaged or broken. By having a separate insertion point (end 132) into the PCBA 114, the PCBA may be inserted after ultrasonic welding of the core is complete. Furthermore, the direction of insertion of the PCBA 114 into end 132 is orthogonal to the insertion direction of the cores 106 and 110 in some embodiments. By having separate insertions between the PCBA 114 and the cores 106 and 110, the cover 104 may be welded to the housing 102 before the PCBA 114 is inserted into end 132.

[0022] In the exemplary embodiment, end 132 of housing 102 features rigid locating features 134a-b (collectively "locating features 134") for retaining PCBA 114 during press-fit pin insertion. Locating features 134 help control movement of PCBA 114 from electrical connector receptacle 126. Additionally, the rigidity of locating features 134 retains PCBA 114 during press-fit pin insertion.

[0023] An opening 128 in housing 102 allows a carrier conductor, such as a cable, wire, or bus bar, to be inserted therethrough. Current flowing in the carrier conductor generates magnetic fields in cores 106 and 110, both of which are orthogonal to the current path. ASIC 122 senses the magnetic field on core 106, and ASIC 124 senses the magnetic field on core 110. Dual-channel current sensor 100 is so named because, on one channel, ASIC 122 measures the magnetic field on core 106 to determine the current flowing in the carrier conductor, and simultaneously, on a second channel, ASIC 124 measures the magnetic field on core 110 to determine the same current flowing in the carrier conductor.

[0024] The housing 102 further includes grommets 130a-b (collectively, "grommets 130") that are part of the housing 102. In addition to enclosing a carrying conductor, such as a cable or bus bar, the grommets 130 provide an additional means for securing the dual channel current sensor 100 to a chassis, wall, or other stationary surface.

[0025] In an exemplary embodiment, the first core 106 and the second core 110 of the dual-channel current sensor 100 are designed to provide two ranges of current sensing. In an exemplary embodiment, the first core 106, which is larger than the second core 110, is designed to sense a relatively wide range of current, while the second core 110 is designed to sense a relatively narrow range of current. In a non-limiting embodiment, the dual-channel current sensor 100 is used in electric vehicle (EV) applications, specifically, in battery systems and battery charging systems.

[0026] In an exemplary embodiment, the first core 106 is capable of measuring current within a range of + / - 1000 A, while the second core 110 is capable of measuring current within a range of + / - 100 A. The dual-channel current sensor 100 therefore provides very good accuracy for the low current range for better Amp-hour integration. Amp-hour is a rating used to determine how many amperage a battery can provide for exactly one hour.

[0027] A magnetic core is a magnetic material with high magnetic permeability. It is made of a ferromagnetic material such as iron or a ferromagnetic compound such as ferrite. Traditionally, magnetic cores are made by wrapping magnetic wire around a shape to create the magnetic core. Wound magnetic cores are therefore limited by the possible shapes around which the wire can be wrapped. In contrast, stamped magnetic cores are made by depositing magnetic material such as silicon steel, nickel ferrite, or other materials into a mold. Stamped magnetic cores can therefore assume virtually any mold shape. Advantages of forming a core into a specific shape include improving the linearity of current measurement and influencing the saturation point of the core. The cost of stamped cores is also generally lower than that of wound cores with similar capabilities. Therefore, there are fewer limitations when using stamped magnetic cores. In addition to being cheaper, stamped magnetic cores allow for the creation of specific shapes that improve linearity.

[0028] In the exemplary embodiment, the cylindrical cavity 112 of the housing 102 features a flat area 136 disposed on the inner surface of the cylindrical cavity. A cylinder, on the other hand, is a three-dimensional shape consisting of two parallel circular bases joined by a curved surface, with a portion of the curved surface flattened into a plane, which is the flat area 136. The flat area 136 is designed to accommodate a stamped core having a flat portion on its inner surface. Thus, a stamped core that is also cylindrical in shape has a flat surface to accommodate the flat area 136. Nevertheless, the housing 102, or more specifically the cylindrical cavity 112, of the dual-channel current sensor 100 can accommodate either a wound core or a stamped core. The dual-channel current sensor 100 is therefore flexible enough to accommodate different application environments.

[0029] 2A-2B are representative diagrams of a dual channel current sensor 200 according to an exemplary embodiment. FIG. 2A is a perspective view of the dual channel current sensor 200, and FIG. 2B is a side view. The housing 102, spacer 108, core 110, and PCBA 114 remain unchanged from the dual channel current sensor 100. The core 206 is a large diameter core disposed in the upper portion of the cylindrical cavity 112. In an exemplary embodiment, the core 206 is a wound core. In some embodiments, the core 110 is a wound core. In other embodiments, the core 110 is a stamped core.

[0030] 2B, core 206 is shown with two portions, 206a and 206b, on either side of opening 128. Portion 206a is substantially similar to portion 206b because, being a wound core, core 206 is generally uniform around its circumference. Nevertheless, core 206 fits into cylindrical cavity 112 of housing 102.

[0031] 3A-3B are representative diagrams of a dual channel current sensor 300 according to an exemplary embodiment. FIG. 3A is a perspective view of the dual channel current sensor 300, and FIG. 3B is a side view. The housing 102, spacer 108, core 110, and PCBA 114 remain unchanged from the dual channel current sensor 100. The core 306 is a large diameter core disposed in the top of the cylindrical cavity 112. In an exemplary embodiment, the core 306 is a stamped core. In some embodiments, the core 110 is a wound core. In other embodiments, the core 110 is a stamped core.

[0032] 3B, core 306 is shown with two portions, 306a and 306b, on either side of opening 128. Portion 306a differs from portion 306b, in contrast to portions 206a and 206b of wound core 206. This is because stamped core 306 may be produced from a mold. Like wound core 206, stamped core 306 fits into cylindrical cavity 112 of housing 102. The single hollow ring of cylindrical cavity 112 is designed to accommodate both wound and stamped cores for measuring a large current range.

[0033] 4A-4D are representative diagrams of the dual channel current sensor 300 of FIGS. 3A-3B as well as a stamped core 306, according to an exemplary embodiment. FIG. 4A is a perspective view of the dual channel current sensor 300, FIGS. 4B-4C are perspective views of the stamped core 306, and FIG. 4D is a perspective view of the internal structure of the dual channel current sensor 300. In FIG. 4A, the housing 102 is shown with the flat area 136 of the cylindrical cavity 112 already installed. In FIGS. 4B-4D, the stamped core 306 is shown. In some embodiments, the stamped core 306 is made using silicon steel. In other embodiments, the stamped core 306 is made using nickel ferrite.

[0034] In the exemplary embodiment, the stamped core 306 also has a flat area 402. Recall that the housing 102 of the dual channel current sensor 300 is designed to accept either a wound core or a stamped core. Nevertheless, in the exemplary embodiment, the stamped core 306 fits into the cylindrical cavity 112, such that the flat area 402 of the stamped core 306 fits against the flat area 136 of the housing 102. The flat area 402 of the stamped core 306 makes the stamped core slightly thicker on its back side. In the exemplary embodiment, the increased surface area of the stamped core 306 provides a larger linear area that includes rounded surfaces.

[0035] Further, stamped core 306 is characterized by a first portion 404, a second portion 406, and a third portion 408. First portion 404 occupies a majority of the circumference of stamped core 306 and is at a first height h1. Second portion 406 is adjacent to one side of gap 410, and third portion 408 is adjacent to the other side of the gap. Second portion 406 resembles a step downward from the flat top surface of stamped core 306. Similarly, third portion 408 resembles a step downward from the flat top surface of stamped core 306. Second portion 406 and third portion 408 are at a second height h2, where h1 > h2. The stamped core 306 is thus a cylindrical core of height h1 (larger than that of the small diameter core 310), which is open at one end with a gap 410, on either side of which are two portions 406 and 408 with a smaller height h2. On the other side of the gap 410 is a flat area 402.

[0036] In the exemplary embodiment, stamped core 306 is shaped as shown to increase its saturation point, allowing for a larger linear range of current measurement. Like flat area 402, in the exemplary embodiment, portions 404, 406, and 408 of stamped core 306 increase the linear range of stamped core 306.

[0037] 4D , gap 410 in stamped core 306 provides an opening through which PCBA 114 is disposed. Similarly, core 110 has gap 414. In an exemplary embodiment, cores 306 and 110 are positioned within housing 102 so that gaps 410 and 414 are aligned with one another. ASIC 122 on PCBA 114 is positioned between gap 410 in stamped core 306, while ASIC 124 is positioned between gap 414 in smaller diameter core 110. Spacer 108 provides separation between stamped core 306 and smaller diameter core 110, allowing ASICs 122 and 124 to separately and accurately obtain current information about the conductors they carry without interference from one another.

[0038] Connector pins 412a and 412b (collectively "connector pins 412") are shown. In the exemplary embodiment, there are four connector pins 412: one for power, one for ground, and two for signal. The connector pins 412 have press-fit features. Rigid locators 134 hold the PCBA 114 during press-fit of the connector pins 412.

[0039] 5 is a representative graph 500 illustrating the characteristics of dual channel current sensor 300, according to an exemplary embodiment. Graph 600 plots the magnetic field against a given current measured by dual channel current sensor 300 for a current range between −1500 A and 1500 A, and the results are highly linear. In an exemplary embodiment, ASIC 122 and stamped core 106 provide the data shown in graph 500.

[0040] 6 is a representative graph 600 illustrating the characteristics of dual channel current sensor 300, according to an exemplary embodiment. Graph 600 plots the magnetic field against a given current measured by dual channel current sensor 300 for a current range between −100 A and 100 A. Similar to graph 500, the results in graph 600 are highly linear. In an exemplary embodiment, ASIC 124 and small diameter core 110 provide the data shown in graph 600.

[0041] By having two sets of data, the dual channel current sensor 300 can provide high accuracy as well as very good precision in the low current range for better Amp-hr integration, which is useful for EV battery technology.

[0042] As used herein, elements or steps described in the singular and preceded by the word "a" or "one" should be understood as not excluding a plurality of elements or steps unless such exclusion is expressly stated. Furthermore, references to "one embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0043] While the present disclosure refers to particular embodiments, many modifications, variations, and variations can be made to the described embodiments without departing from the sphere and scope of the present disclosure as defined in the appended claims. Accordingly, it is intended that the present disclosure not be limited to the described embodiments, but rather have the full scope defined by the language of the following claims and equivalents thereof.

Claims

1. a housing including a cylindrical cavity and an end adjacent said cylindrical cavity, wherein said cylindrical cavity has a closed bottom and a first opening in a first direction at a first end of said housing, and said end has a second opening in a second direction at a second end of said housing; a first core having a cylindrical shape and including flat top and bottom surfaces; The first core comprises: a flat area disposed on the inner surface; a gap disposed perpendicular to and opposite said flat area; a first portion disposed adjacent a first side of the gap; a second portion disposed adjacent a second side of the gap; and a third portion disposed around the circumference of the first core between the first portion and the second portion; and the second side is opposite the first side; wherein the heights of the first portion and the second portion are smaller than the height of the third portion; wherein the first opening at the first end of the housing is sized and oriented for insertion of the first core therein in the first direction; a second core including a second gap, wherein the first opening at the first end of the housing is sized and oriented for insertion of the second core therein in the first direction; a spacer, wherein the first opening in the first end of the housing is sized and oriented for insertion of the spacer therein in the first direction, and wherein the second core is located at the closed bottom of the cylindrical cavity, and wherein the spacer is located within the cylindrical cavity above the second core and the first core is located within the cylindrical cavity above the spacer; and a printed circuit board assembly (PCBA) including a first sensor and a second sensor, the first sensor disposed in the gap and the second sensor disposed in the second gap, wherein the second opening in the second end of the housing is sized and oriented for insertion of the PCBA therein in the second orientation; Here, the second direction is perpendicular to the first direction. A current sensor comprising:

2. The first core includes a first height and the second core includes a second height that is less than the first height. The current sensor according to claim 1 .

3. The current sensor of claim 1 , wherein the housing further includes a second flat area disposed on a second inner surface of the cylindrical cavity.

4. The current sensor of claim 3 , wherein the flat area is aligned with the second flat area once the first core is disposed within the cylindrical cavity.

5. The current sensor of claim 2 , wherein the first and second sensors are Hall sensors.

6. The current sensor of claim 1 , wherein the housing further includes a pair of rigid positioning portions that hold the PCBA.

7. The current sensor of claim 1 , wherein the housing further comprises an electrical connector receptacle coupled to a power source.

8. The current sensor of claim 2 , wherein the first core is a stamped core and the second core is a wound core.

9. The current sensor of claim 2 , wherein the first core is a wound core and the second core is a second wound core.

10. 10. The current sensor of claim 2, wherein the first sensor provides a current measurement within a range of ±1500 amperes.

11. The current sensor of claim 2 , wherein the second sensor provides a current measurement within a range of ±100 amperes.

12. The current sensor of claim 1 , further comprising a top cover covering the first opening at the first end of the cylindrical cavity adjacent the first core and closing the cylindrical cavity of the housing.

13. The current sensor of claim 12 , further comprising a side cover covering the second opening at the second end of the end of the housing and sealing the PCBA within the housing.

14. 13. The current sensor of claim 12, wherein the second opening at the second end of the end of the housing remains open to accommodate the PCBA therein after the top cover is welded to the housing.

15. A method for manufacturing a current sensor, comprising: inserting a first core, a spacer, and a second core into a first opening that opens in a first direction at a first end of a housing that includes a cylindrical cavity having a closed bottom and an end adjacent to the cylindrical cavity; wherein the second core is located at the closed bottom of the cylindrical cavity, wherein the spacer is located above the second core within the cylindrical cavity, and the first core is located above the spacer within the cylindrical cavity; welding a top cover to cover the first opening and close the cylindrical cavity; After the welding step, inserting a PCBA including a first sensor and a second sensor into a second opening that opens in a second direction perpendicular to the first direction at a second end of the end of the housing; after inserting the PCBA, covering the second opening and sealing the PCBA inside the housing with a side cover; Equipped with The first core comprises: a flat area disposed on the inner surface; a gap disposed perpendicular to and opposite said flat area; a first portion disposed adjacent a first side of the gap; a second portion disposed adjacent a second side of the gap; and a third portion disposed around the circumference of the first core between the first portion and the second portion, wherein the heights of the first portion and the second portion are smaller than the height of the third portion; the second side is opposite the first side; the step of inserting the PCBA is a step of inserting the PCBA into the second opening so that the first sensor is disposed in the gap; Manufacturing method.

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