CN113466530A

CN113466530A - Current sensor

Info

Publication number: CN113466530A
Application number: CN202010246039.7A
Authority: CN
Inventors: 杨伟; 刘双; 高洪良
Original assignee: BYD Semiconductor Co Ltd
Current assignee: BYD Semiconductor Co Ltd
Priority date: 2020-03-31
Filing date: 2020-03-31
Publication date: 2021-10-01

Abstract

The present disclosure relates to a current sensor comprising: an electromagnetic assembly (1), the electromagnetic assembly (1) comprising a magnetic core (11) and a secondary winding (13), the secondary winding (13) being wound around the magnetic core (11), the magnetic core (11) being configured in a ring shape and being formed with a cross-shaped air gap comprising a longitudinal air gap (111) and a transverse air gap (112) which are perpendicular, the longitudinal air gap (111) extending in a radial direction of the magnetic core (11) to form a truncated opening; and a circuit board assembly (2), the circuit board assembly (2) comprising a magneto-sensitive element (23), the magneto-sensitive element (23) being located in the transverse airgap (112) and having an inductive surface, the inductive surface being parallel to a direction of a magnetic field in the transverse airgap (112). Through above-mentioned technical scheme, the current sensor that this disclosure provided has higher detection accuracy and linearity isoparametric, and has the characteristics that the low temperature floats.

Description

Current sensor

Technical Field

The present disclosure relates to the field of sensor technology, and in particular, to a current sensor.

Background

A current sensor is a device that senses a sensed current and converts the sensed current into a usable output signal, and is generally used for sensing ac and dc currents.

The current sensor is based on the hall principle and mainly comprises an open-loop hall current sensor and a closed-loop hall current sensor, wherein a magnetic field around a measured current is sensed by a hall element and converted into an electric signal, and then the electric signal passes through a series of processing circuits and is output to meet the requirement to realize current detection.

However, due to the defects of the existing hall element, the existing hall element cannot meet the higher requirements of the current sensor on the precision, the linearity, the temperature drift and other parameters in many fields.

Disclosure of Invention

The purpose of this disclosure is to provide a current sensor, this current sensor can detect the electric current more accurately, has higher detection accuracy and linearity isoparametric, and has the characteristics that the low temperature floats.

In order to achieve the above object, the present disclosure provides a current sensor including: an electromagnetic assembly including a magnetic core and a secondary coil wound around the magnetic core, the magnetic core being configured in a ring shape and formed with a cross air gap including a vertical longitudinal air gap and a lateral air gap perpendicular to each other, the longitudinal air gap extending in a radial direction of the magnetic core to form a cutout opening; and a circuit board assembly comprising a magneto-sensitive element located in the transverse air gap and having an induction surface parallel to a direction of a magnetic field in the transverse air gap.

Optionally, the magneto-sensitive element is integrated with a fluxgate induction circuit, wherein the magnetic field in the transverse air gap generates an induced electrical signal in the fluxgate induction circuit.

Optionally, the magnetic sensing element is integrated with: the integral filter circuit is used for modulating and demodulating the induction electric signal to obtain a driving electric signal; the H-bridge driving circuit is used for providing driving current for the secondary coil through the driving electric signal; and the amplifying circuit amplifies the compensation current into a standard signal and outputs the standard signal.

Optionally, the H-bridge driving circuit includes an MOS transistor, and an MOS transistor, which are all controlled by the magnetic sensing element and are all electrically connected to the secondary coil, and when the magnetic sensing element controls the MOS transistor and the MOS transistor to be in an on state and the MOS transistor to be in an off state, the driving current flows from the MOS transistor to the MOS transistor through the secondary coil; when the magnetic sensing element controls the MOS tube and the MOS tube to be in a turn-off state and the MOS tube to be in an open state, the driving current flows to the MOS tube from the MOS tube through the secondary coil.

Optionally, the amplifying circuit includes an operational amplifier, a resistor, and a sampling resistor, the sampling resistor, the resistor, and the resistor are sequentially connected in series, a negative phase input terminal of the operational amplifier is connected between the resistor and the resistor, and a positive phase input terminal of the operational amplifier is connected between the resistor and the resistor; the sampling resistor, the secondary coil and the H-bridge driving circuit are connected in series.

Optionally, a central plane of the transverse air gap bisects the longitudinal air gap, a central plane of the longitudinal air gap bisects the transverse air gap, a position where a center of the transverse air gap coincides with a center of the longitudinal air gap is a central position of the cross air gap, and the fluxgate induction circuit is located at the central position of the cross air gap.

Optionally, the current sensor includes a housing formed with a central axial bore through which the primary current conductor passes, and the housing includes a housing body and a housing cover connected to define an enclosed space in which the electromagnetic assembly and the circuit board assembly are mounted, and the electromagnetic assembly is disposed coaxially with the central axial bore.

Optionally, the current sensor comprises an inner and an outer shield ring disposed in the enclosed space and arranged coaxially with the central axial bore, the electromagnetic assembly being disposed between the inner and outer shield rings.

Optionally, the housing is provided with a first shaft barrel, the housing cover is provided with a second shaft barrel, the first shaft barrel is sleeved on the second shaft barrel and attached to the second shaft barrel, the first shaft barrel and the second shaft barrel jointly define the central shaft hole, and the inner shielding ring is sleeved on the first shaft barrel; an inner shielding ring positioning structure is arranged on the shell body or the shell cover, the inner shielding ring positioning structure comprises a first axial positioning structure used for limiting the inner shielding ring to move relative to the shell in the axial direction and a first transverse positioning structure used for limiting the inner shielding ring to move relative to the shell in the transverse direction, and the transverse direction is perpendicular to the axial direction.

Optionally, the housing or the housing cover is provided with an outer shielding ring positioning structure, and the outer shielding ring positioning structure includes a second axial positioning structure for limiting the outer shielding ring to move in the axial direction relative to the housing and a second transverse positioning structure for limiting the outer shielding ring to move in the transverse direction relative to the housing, and the transverse direction is perpendicular to the axial direction.

Optionally, the circuit board assembly includes a PCB and an interposer, the interposer is fixed on the PCB and electrically connected to the PCB, the magnetic sensor has a back surface opposite to the sensing surface, the back surface is fixed to the interposer, and the PCB is disposed perpendicular to the axial direction and fixed to the magnetic core.

Optionally, the electromagnetic assembly includes an insulating housing covering the magnetic core, the PCB is fixed to the insulating housing, a magnetic core limiting structure for limiting the movement of the magnetic core relative to the housing is formed between the insulating housing and the housing, and a PCB limiting structure for limiting the movement of the PCB relative to the housing is formed between the housing and the PCB.

Optionally, the insulating housing is provided with a positioning bracket corresponding to the cross air gap, the positioning bracket is located between the PCB board and the insulating housing to maintain the position of the magnetic sensing element in the cross air gap, and the positioning bracket is formed with a through hole for the adapter board and the magnetic sensing element to pass through.

Optionally, the circuit board assembly includes a current input pin and a signal output pin, and one end of the current input pin and the signal output pin are fixed on the PCB board to be electrically connected to the magnetic sensor.

Through the technical scheme, the current sensor provided by the disclosure detects the magnetic field in the transverse air gap by using the magnetic sensing element with stable and excellent performance, and converts the magnetic field into an induction electric signal by the magnetic sensing element, so that the detection work of primary side current is realized. The opening size of the longitudinal air gap is designed to enable the magnetic field intensity which can be detected by the magnetic sensing element at the central position of the cross air gap to be in a numerical range which can be sensitively and accurately detected by the magnetic sensing element, and therefore the detection accuracy and the linearity of the current sensor are beneficially improved. Because the magnetic sensing element provided by the disclosure has stable performance, the current sensor provided by the disclosure is less affected by temperature change and has the characteristic of low temperature drift.

Additional features and advantages of the disclosure will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure without limiting the disclosure. In the drawings:

Fig. 1 is an exploded perspective view of a current sensor provided in an embodiment of the present disclosure;

fig. 2 is a schematic top view of a current sensor provided in an embodiment of the present disclosure;

FIG. 3 is a cross-sectional view taken along line A-A of FIG. 2;

fig. 4 is a schematic perspective view of a current sensor provided in an embodiment of the present disclosure, in which a cover is hidden;

FIG. 5 is a schematic perspective view of a current sensor provided by an embodiment of the present disclosure, in which a housing cover and a circuit board assembly are hidden;

FIG. 6 is a schematic perspective view of an electromagnetic assembly in a current sensor provided by an embodiment of the present disclosure;

fig. 7 is a schematic perspective view of a magnetic core in a current sensor provided by an embodiment of the present disclosure;

FIG. 8 is a schematic diagram of another perspective view of a magnetic core in a current sensor according to an embodiment of the present disclosure, wherein the magnetic sensing element is shown in a transverse air gap;

fig. 9 is a schematic perspective view of an insulating housing in a current sensor provided by an embodiment of the present disclosure;

fig. 10 is another schematic perspective view of an insulating housing in a current sensor provided by an embodiment of the present disclosure;

fig. 11 is a schematic perspective view of a circuit board assembly in a current sensor provided by an embodiment of the present disclosure;

FIG. 12 is a schematic top view of a housing in a current sensor provided by an embodiment of the present disclosure;

FIG. 13 is a sectional view taken along line B-B of FIG. 12;

fig. 14 is a partial enlarged view of fig. 13;

FIG. 15 is a schematic perspective view of a housing cover in a current sensor according to an embodiment of the disclosure;

FIG. 16 is a block circuit diagram of a current sensor provided by an embodiment of the present disclosure;

FIG. 17 is a schematic diagram of an H-bridge driver circuit integrated with a magnetic sensor in a current sensor according to an embodiment of the disclosure.

Description of the reference numerals

1-an electromagnetic component, 11-a magnetic core, 111-a longitudinal air gap, 112-a transverse air gap, 12-an insulating shell, 121-a square bulge, 122-a positioning bracket, 123-a fabrication hole, 124-a thread mounting post, 13-a secondary coil, 131-a connecting pin, 2-a circuit board component, 21-a PCB board, 211-a positioning hole, 22-an adapter plate, 23-a magnetic sensitive element, 24-a current input pin, 25-a signal output pin, 3-an inner shielding ring, 4-an outer shielding ring, 51-a shell, 511-a positioning bulge, 512-a first shaft cylinder, 513-a square groove, 514-a positioning column, 515-a connecting clamping groove, 52-a shell cover, 521-an abutting bulge, 522-a second shaft cylinder and 523-an annular positioning rib, 524-axial limiting protrusion, 525-connecting buckle, 6-mounting column, 61-anti-tripping, Q1-MOS tube, Q2-MOS tube, Q3-MOS tube, Q4-MOS tube, U1-operational amplifier, R1-resistor, R2-resistor, R3-resistor, R4-resistor and R5-sampling resistor.

Detailed Description

The following detailed description of specific embodiments of the present disclosure is provided in connection with the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present disclosure, are given by way of illustration and explanation only, not limitation.

In the present disclosure, the use of directional terms such as "inner and outer" means "inner and outer" with respect to the corresponding profile of the component itself, unless otherwise specified. In addition, the terms "first, second, etc. used in the present disclosure are intended to distinguish one element from another, and are not necessarily sequential or important. Furthermore, in the following description, when referring to the figures, the same reference numbers in different figures denote the same or similar elements, unless otherwise explained. The foregoing definitions are provided to illustrate and describe the present disclosure only and should not be construed to limit the present disclosure.

According to a specific embodiment of the present disclosure, referring to fig. 1 to 17, there is provided a current sensor including: the electromagnetic assembly 1 comprises a magnetic core 11 and a secondary coil 13, wherein the secondary coil 13 is wound on the magnetic core 11, the magnetic core 11 is annular and is formed with a cross air gap, the cross air gap comprises a vertical longitudinal air gap 111 and a transverse air gap 112 which are perpendicular to each other, and the longitudinal air gap 111 extends along the radial direction of the magnetic core 11 to form a cut-off opening; and a circuit board assembly 2, the circuit board assembly 2 comprising a magneto-sensitive element 23, the magneto-sensitive element 23 being located in the transverse air gap 112 and having a sensing surface which is parallel to the direction of the magnetic field in the transverse air gap 112.

Through the technical scheme, the current sensor provided by the disclosure detects the magnetic field in the transverse air gap 112 by using the magnetic sensing element 23 with stable and excellent performance, and converts the magnetic field into an induced electrical signal by the magnetic sensing element 23, so that the detection work of the primary current is realized. Wherein, the transverse air gap 112 provides an installation space for the magnetic sensing element 23, the opening size of the longitudinal air gap 111 affects the magnetic field intensity parallel to the sensing surface of the magnetic sensing element 23 at the center position of the cross air gap, the sensing surface of the magnetic sensing element 23 is the surface capable of sensing the magnetic field, therefore, the opening size of the longitudinal air gap 111 is designed to make the magnetic field intensity detected by the magnetic sensing element 23 at the center position of the cross air gap be in the value range capable of sensitively and accurately detecting the magnetic sensing element 23, thereby being beneficial to improving the detection accuracy and linearity of the current sensor. Because the magnetic sensing element 23 provided by the present disclosure has stable performance, the current sensor provided by the present disclosure is less affected by temperature change, and has the characteristic of low temperature drift.

In the specific embodiment provided by the present disclosure, the magneto-sensitive element 23 is integrated with a fluxgate induction circuit, and the magnetic field in the transverse air gap 112 generates an induced electrical signal in the fluxgate induction circuit. The secondary coil 13 is electrically connected with the magnetic sensing element 23, a primary induced magnetic field generated by a primary current in the magnetic core 11 comprises a primary parallel magnetic field in the transverse air gap 112, the fluxgate induction circuit is arranged in parallel with the primary parallel magnetic field by relying on a component in the magnetic sensing element 23, the primary parallel magnetic field generates an induced electric signal in the fluxgate induction circuit, the induced electric signal provides a driving current for the secondary coil 13 so as to obtain a compensation current in the secondary coil 13, the secondary induced magnetic field generated by the compensation current in the magnetic core 11 comprises a secondary parallel magnetic field in the transverse air gap 112, the secondary parallel magnetic field is opposite to the primary parallel magnetic field in direction, and when the sum of the magnetic fluxes of the primary parallel magnetic field and the secondary parallel magnetic field is zero, the compensation current proportionally reflects the primary current.

Wherein, alternatively, the cross section of the magnetic core 11 may be configured as a quadrangle, the magnetic core 11 has a first end surface and a second end surface which are oppositely arranged along the axial direction and an inner ring surface and an outer ring surface which are oppositely arranged along the radial direction, referring to fig. 7, the longitudinal air gap 111 penetrates through the first end surface and the second end surface and also penetrates through the inner ring surface and the outer ring surface, the transverse air gap 112 penetrates through the first end surface and the second end surface but does not penetrate through the inner ring surface and the outer ring surface, and the longitudinal air gap 111 and the transverse air gap 112 intersect to form a cross air gap. In other embodiments, the cross-section of the magnetic core 11 may be configured in other desired shapes such as a circle, a hexagon, etc., and the present disclosure is not particularly limited thereto.

Wherein optionally the opening of the longitudinal air gap 111 is dimensioned such that the magneto-sensitive element 23 is in an optimal operating magnetic field. Alternatively, the opening of the longitudinal air gap 111 may be sized such that when the measured current reaches a maximum value, the magnetic field in the cross air gap will not saturate, and when the measured current is small, the current sensor can still detect accurately, i.e. the magnetic sensor 23 is considered to be in the optimal operating magnetic field.

In the specific embodiment provided in the present disclosure, referring to fig. 16, the magnetic sensing element 23 may be integrated with: the integral filter circuit is used for modulating and demodulating the induced electrical signal by the integral filter circuit to obtain a driving electrical signal; an H-bridge driving circuit, which supplies a driving current to the secondary coil 13 via a driving electric signal; and the amplifying circuit amplifies the compensation current into a standard signal and outputs the standard signal.

As shown in fig. 17, the H-bridge driving circuit may include a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, and a MOS transistor Q4, and the MOS transistor Q1, the MOS transistor Q2, the MOS transistor Q3, and the MOS transistor Q4 are all controlled by the magnetic sensor 23 and are all electrically connected to the secondary coil 13. When the magnetic sensing element 23 controls the MOS transistor Q1 and the MOS transistor Q4 to be in an open state, and the MOS transistor Q2 and the MOS transistor Q3 to be in a closed state, the driving current flows from the MOS transistor Q1 to the MOS transistor Q4 through the secondary coil 13; when the magnetic sensor 23 controls the MOS transistor Q1 and the MOS transistor Q4 to be in an off state and the MOS transistor Q2 and the MOS transistor Q3 to be in an on state, the drive current flows from the MOS transistor Q3 to the MOS transistor Q2 through the secondary coil 13.

As shown in fig. 16, the amplifying circuit may include an operational amplifier U1, a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a sampling resistor R5, wherein the resistor R2, the resistor R1, the sampling resistor R5, the resistor R3, and the resistor R4 are sequentially connected in series, a negative phase input terminal of the operational amplifier U1 is connected between the resistor R1 and the resistor R2, and a positive phase input terminal of the operational amplifier U1 is connected between the resistor R3 and the resistor R4; the sampling resistor R5, the secondary coil 13 and the H-bridge drive circuit are connected in series to form an amplifying circuit with 4 times of gain, and the voltage at two ends of the sampling resistor R5 is amplified and then output. Here, the expression of the output voltage may be set at the external terminal, for example, it may be set in a standard voltage manner, it may be set in a bias voltage output manner, or both, as shown in fig. 16. In this regard, the present disclosure is not particularly limited.

In the specific embodiment provided by the present disclosure, the central plane of the transverse air gap 112 bisects the longitudinal air gap 111, the central plane of the longitudinal air gap 111 bisects the transverse air gap 112, a position where the center of the transverse air gap 112 coincides with the center of the longitudinal air gap 111 is a central position of the cross air gap, and the fluxgate sensing circuit is located at the central position of the cross air gap, that is, the fluxgate sensing circuit is located at a position where a more uniform primary-side parallel magnetic field can be detected, which is beneficial to the detection of the primary-side parallel magnetic field by the magnetic sensor element 23, so as to obtain more accurate detection data.

In the specific embodiment provided by the present disclosure, the number of turns of the secondary winding 13 may be set as needed to meet the actual use requirement, and therefore, the present disclosure does not specifically limit this.

In the embodiment provided by the present disclosure, the current sensor includes a housing, the housing is formed with a central shaft hole through which the primary current conductor passes, and the housing includes a housing body 51 and a housing cover 52, the housing body 51 and the housing cover 52 are connected and define a housing space, the electromagnetic assembly 1 and the circuit board assembly 2 are mounted in the housing space, and the electromagnetic assembly 1 is disposed coaxially with the central shaft hole. The housing 51 and the housing cover 52 may be connected by a clamping structure, the clamping structure includes a connecting buckle 525 and a connecting card slot 515, the connecting buckle 525 is disposed on one of the housing 51 and the housing cover 52, and the connecting card slot 515 is disposed on the other of the housing 51 and the housing cover 52. For example, as shown in fig. 5, a connection card slot 515 is provided on the housing 51; as shown in fig. 15, the connection catch 525 is provided on the housing cover 52. In order to ensure the connection reliability between the housing 51 and the housing cover 52, the number of the snap structures may be plural and arranged at intervals around the central axis of the central shaft hole.

The current sensor provided by the present disclosure is generally applied to devices or apparatuses, and therefore, in order to implement the installation and fixation of the current sensor in the devices or apparatuses, the housing 51 may be provided with the mounting post 6, and the mounting post 6 is connected to the housing 51 by means of crimping, so as to implement the installation and fixation through the portion of the mounting post 6 exposed to the housing 51. Alternatively, the mounting post 6 may be provided with an anti-trip device 61, and the mounting post 6 is prevented from being removed from the housing 51 by the anti-trip device 61, thereby ensuring the reliability of the current sensor during use.

When the current sensor is applied to an apparatus or device, there are other currents or magnetic fields around it in general, and therefore, in order to prevent these currents and magnetic fields from generating unnecessary interference, the current sensor may include an inner shield ring 3 and an outer shield ring 4 disposed in the receiving space and arranged coaxially with the central axis hole, the electromagnetic assembly 1 being disposed between the inner shield ring 3 and the outer shield ring 4, i.e., the inner shield ring 3 is located in the inner annular hole of the magnetic core 11, and the outer shield ring 4 is located outside the outer annular ring of the magnetic core 11. Wherein, interior shield ring 3 and outer shield ring 4 are the silicon steel magnetic ring, through coiling shaping and through high temperature annealing to prevent interior shield ring 3 and the 4 stress deformation of outer shield ring, the interior shield ring 3 after the annealing and the 4 crystalline grain arrangement of outer shield ring are more neat, and the effect of shielding interference signal around electromagnetic component 1 is better. In addition, in order to achieve the desired shielding effect, the axial length of the inner and outer shielding rings 3, 4 is greater than the size of the electromagnetic assembly 1, in other words, the electromagnetic assembly 1 is located completely between the inner and outer shielding rings 3, 4.

In order to prevent the inner shield ring 3 and the outer shield ring 4 from being displaced in the housing and affecting the shielding effect, and to reduce or even avoid noise caused by the displacement, the inner shield ring 3 and the outer shield ring 4 need to be positioned.

In the embodiments provided in the present disclosure, the inner shield ring 3 may be positioned by providing a suitable structure. Alternatively, as shown in fig. 1 and fig. 3, the housing 51 is provided with a first shaft cylinder 512, the housing cover 52 is provided with a second shaft cylinder 522, the first shaft cylinder 512 is sleeved on the second shaft cylinder 522 and is attached to the second shaft cylinder 522, the first shaft cylinder 512 and the second shaft cylinder 522 jointly define a central shaft hole, and the inner shielding ring 3 is sleeved on the first shaft cylinder 512. The housing body 51 or the housing cover 52 is provided with an inner shield ring positioning structure, which includes a first axial positioning structure for limiting the movement of the inner shield ring 3 in the axial direction relative to the housing and a first transverse positioning structure for limiting the movement of the inner shield ring 3 in the transverse direction relative to the housing, wherein the transverse direction is perpendicular to the axial direction.

By the first axial positioning structure and the first lateral positioning structure, the inner shield ring 3 can be held firmly and stably in the housing. In the specific embodiments provided by the present disclosure, the first axial locating feature and the first lateral locating feature may each be configured in any suitable manner.

Alternatively, as shown in fig. 3 and fig. 15 in combination, the first axial positioning structure may include an abutting surface and an annular positioning rib 523, wherein the annular positioning rib 523 is formed on the second shaft 522, the inner surface of the housing 51 is configured as the abutting surface, and the inner shielding ring 3 abuts between the abutting surface and the annular positioning rib 523, so that the inner shielding ring 3 can be restricted from moving in the axial direction relative to the housing.

Alternatively, the first lateral positioning structure may include a first lateral limiting surface and a second lateral limiting surface, the first lateral limiting surface may be an outer surface of the first shaft 512, the second lateral limiting surface may be an inner surface of the inner shielding ring 3, and the inner shielding ring 3 is sleeved on the first shaft 512 and is attached to the first shaft 512 to limit the inner shielding ring 3 from moving laterally relative to the housing. Here, it can also be understood that the inner shielding ring 3 is fitted over the first shaft tube 512 in an interference fit manner.

Likewise, in the embodiments provided by the present disclosure, the outer shield ring 4 may be positioned by providing suitable structure. Alternatively, the housing 51 or the housing cover 52 is provided with an outer shield ring positioning structure, which includes a second axial positioning structure for limiting the movement of the outer shield ring 4 in the axial direction relative to the housing and a second lateral positioning structure for limiting the movement of the outer shield ring 4 in the lateral direction relative to the housing, wherein the lateral direction is perpendicular to the axial direction.

By means of the second axial positioning structure and the second transverse positioning structure, the outer shield ring 4 can be held firmly and stably in the housing. In the specific embodiments provided by the present disclosure, the second axial positioning structure and the second lateral positioning structure may each be configured in any suitable manner.

Alternatively, as shown in fig. 3 and fig. 15, the second axial positioning structure may include an abutting protrusion 521, where the abutting protrusion 521 is disposed on the housing cover 52 and extends axially to abut against the outer shielding ring 4, and together with the inner surface of the housing 51, may limit the outer shielding ring 4 to move axially relative to the housing 51, that is, one end of the outer shielding ring 4 abuts against the inner surface of the housing 51, and the other end abuts against the abutting protrusion 521.

Alternatively, referring to fig. 12, the second lateral positioning structure may include a positioning protrusion 511, the positioning protrusion 511 may be provided on the housing 51 and provided in plurality at intervals along the circumference of the first shaft 512, and the plurality of positioning protrusions 511 are attached to the inner surface or the outer surface of the outer shield ring 4 to restrict the outer shield closed loop from moving laterally relative to the housing by the positioning protrusions 511.

In the embodiment provided in the present disclosure, in order to achieve the required electrical connection and corresponding functions, the circuit board assembly 2 may include a PCB board 21 and an interposer board 22, the interposer board 22 is fixed on the PCB board 21 and electrically connected with the PCB board 21, the magnetic sensing element 23 is fixed on the interposer board 22, and the PCB board 21 is disposed perpendicular to the axial direction and fixed relative to the magnetic core 11. The secondary coil 13 is electrically connected to the PCB 21 through a connecting pin to establish a connection between the magnetic sensor 23 and the secondary coil 13 through the PCB 21, so that a driving current is supplied to the secondary coil 13 through a fluxgate sensing circuit integrated in the magnetic sensor 23. In addition, the PCB board 21 and the interposer 22 are connected through the bonding pad, so that the position degree between the PCB board 21 and the interposer 22 is ensured, the connection strength is high, and the use reliability of the current sensor can be ensured.

Wherein, in order to prevent the edge corner of the magnetic core 11 from wearing the secondary coil 13, the electromagnetic assembly 1 may include an insulating housing 12 covering the magnetic core 11, the secondary coil is wound on the insulating housing 12, the PCB 21 is fixed to the insulating housing 12, and the insulating housing 12 fixes the magnetic core 11 and plays a role of insulating the magnetic core 11 and the secondary coil 13 at the same time, so as to facilitate the winding of the secondary coil 13. In addition, a plurality of process holes 123 are formed in the insulating housing 12, and the plurality of process holes 123 are uniformly distributed on the insulating housing 12, so that the magnetic core 11 is pressed by a mold during the injection molding of the insulating housing 12, thereby preventing the magnetic core 11 from being deviated.

Here, the magnetic core 11 needs to be positioned in the housing to ensure performance. Therefore, in the specific embodiment provided by the present disclosure, a core limiting structure for limiting the movement of the core 11 relative to the housing 51 may be formed between the insulating housing 12 and the housing 51, and a PCB limiting structure for limiting the movement of the PCB 21 relative to the housing may be formed between the housing and the PCB 21.

Wherein, the magnetic core limit structure can include a groove and a protrusion which are matched with each other, one of the groove and the protrusion is arranged on the shell, and the other one is arranged on the insulating shell 12. The grooves and the protrusions may be square, circular, or any other suitable shape, which is not specifically limited in this disclosure. For example, as shown in fig. 9 and 12 in combination, the groove is configured as a square groove 513, the protrusion is configured as a square protrusion 121, the square groove 513 is provided on the housing 51, the square protrusion 121 is provided on the insulating case 12, and the square groove 513 and the direction protrusion cooperate to restrict the movement of the magnetic core 11 relative to the housing 51 in the circumferential direction and the lateral direction.

Also here the PCB 21 needs to be positioned in the housing, at least to ensure that no relative movement between the PCB 21 and the core 11 can occur. Therefore, in the specific embodiment provided by the present disclosure, optionally, as shown in fig. 3 to 5 and fig. 15, the PCB board 21 is fixed to the insulating housing 12 by screws, and the insulating housing 12 is formed with threaded mounting posts 124, and the screws penetrate through the PCB board 21 and are threadedly coupled with the threaded mounting posts 124. The PCB board limiting structure may include an axial limiting protrusion 524 and a positioning post 514, the limiting protrusion is disposed on the housing cover 52, and the PCB board 21 is supported by the threaded mounting post 124 and is abutted by the axial limiting protrusion 524 to limit the PCB board 21 from moving in the axial direction relative to the housing 51; the positioning posts 514 are disposed on the housing 51 and along the opposite corners of the housing 51, the positioning holes 211 are disposed on the PCB board 21, and the positioning posts 514 and the positioning holes 211 cooperate with each other to restrict the PCB board 21 from moving in the lateral and circumferential directions relative to the housing 51.

The insulating housing 12 may be provided with a positioning bracket 122 corresponding to the cross-shaped air gap, the positioning bracket 122 is located between the PCB 21 and the insulating housing 12 to maintain the position of the magnetic sensor 23 in the cross-shaped air gap, the positioning bracket 122 is formed with a via hole for the interposer 22 and the magnetic sensor 23 to pass through, and the via hole may be adaptively designed according to the interposer 22 and the magnetic sensor 23 to ensure that the fluxgate sensing circuit is located at the center of the cross-shaped air gap.

The secondary winding 13 cannot be wound directly on the magnetic core 11 due to the presence of the insulating case 12, i.e., the secondary winding 13 is wound on the insulating case 12 as shown in fig. 6. The secondary coil 13 needs to be disposed so as to avoid the positioning post 124 and the positioning holder 122. In view of the influence of the magnetic induction and the reliable fixing of the PCB 21, the number of the positioning posts 124 is two, two positioning posts 124 and one positioning bracket 122 are arranged at equal intervals in the circumferential direction of the insulating housing 12, as shown in fig. 10, and the number of turns of the secondary coil 13 is equal between any two of the three.

In addition, in order to realize the input and output of the electrical signal, in the embodiment provided in the present disclosure, the circuit board assembly 2 includes a current input pin 24 and a signal output pin 25, and the current input pin 24 and the signal output pin 25 are fixed on the PCB board 21 to be electrically connected with the magnetic sensor element 23. In one embodiment, the current input pin 24 and the signal output pin 25 may be configured as F-type pins, and are fixed on the PCB 21 at two points, and the surfaces of the current input pin 24 and the signal output pin 25 are plated with tin, so as to facilitate the soldering with the PCB 21 and the soldering with the client, facilitate the installation and improve the connection strength.

The preferred embodiments of the present disclosure are described in detail with reference to the accompanying drawings, however, the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present disclosure within the technical idea of the present disclosure, and these simple modifications all belong to the protection scope of the present disclosure.

It should be noted that, in the foregoing embodiments, various features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various combinations that are possible in the present disclosure are not described again.

In addition, any combination of various embodiments of the present disclosure may be made, and the same should be considered as the disclosure of the present disclosure, as long as it does not depart from the spirit of the present disclosure.

Claims

1. A current sensor, characterized in that the current sensor comprises:

an electromagnetic assembly (1), the electromagnetic assembly (1) comprising a magnetic core (11) and a secondary winding (13), the secondary winding (13) being wound around the magnetic core (11), the magnetic core (11) being configured in a ring shape and being formed with a cross-shaped air gap comprising a longitudinal air gap (111) and a transverse air gap (112) perpendicular to each other, the longitudinal air gap (111) extending in a radial direction of the magnetic core (11) to form a truncated opening, and

A circuit board assembly (2), the circuit board assembly (2) comprising a magneto-sensitive element (23), the magneto-sensitive element (23) being located in the transverse airgap (112) and having an inductive surface, the inductive surface being parallel to a direction of a magnetic field in the transverse airgap (112).

2. The current sensor according to claim 1, characterized in that the magneto-sensitive element (23) is integrated with a fluxgate induction circuit in which the magnetic field in the transverse air gap (112) generates an induced electrical signal.

3. Current sensor according to claim 2, characterized in that the magnetosensitive element (23) integrates:

the integral filter circuit is used for modulating and demodulating the induction electric signal to obtain a driving electric signal;

an H-bridge drive circuit through which the drive electrical signal provides a drive current to the secondary coil (13); and

and the amplifying circuit amplifies the compensation current into a standard signal and outputs the standard signal.

4. Current sensor according to claim 3, characterized in that the H-bridge drive circuit comprises a MOS transistor (Q1), a MOS transistor (Q2), a MOS transistor (Q3) and a MOS transistor (Q4), the MOS transistor (Q1), the MOS transistor (Q2), the MOS transistor (Q3) and the MOS transistor (Q4) being controlled by the magneto element (23) and being electrically connected to the secondary coil (13),

When the magnetic sensing element (23) controls the MOS tube (Q1) and the MOS tube (Q4) to be in an open state, and the MOS tube (Q2) and the MOS tube (Q3) are in an off state, the driving current flows from the MOS tube (Q1) to the MOS tube (Q4) through the secondary coil (13);

when the magnetic sensing element (23) controls the MOS tube (Q1) and the MOS tube (Q4) to be in an off state, and the MOS tube (Q2) and the MOS tube (Q3) are in an on state, the driving current flows from the MOS tube (Q3) to the MOS tube (Q2) through the secondary coil (13).

5. The current sensor according to claim 3, wherein the amplifying circuit comprises an operational amplifier (U1), a resistor (R1), a resistor (R2), a resistor (R3), a resistor (R4), and a sampling resistor (R5),

the resistor (R2), the resistor (R1), the sampling resistor (R5), the resistor (R3) and the resistor (R4) are sequentially connected in series, a negative phase input terminal of the operational amplifier (U1) is connected between the resistor (R1) and the resistor (R2), and a positive phase input terminal of the operational amplifier (U1) is connected between the resistor (R3) and the resistor (R4);

the sampling resistor (R5), the secondary coil (13) and the H bridge drive circuit are connected in series.

6. The current sensor according to claim 2, wherein a central plane of the transverse air gap (112) bisects the longitudinal air gap (111), a central plane of the longitudinal air gap (111) bisects the transverse air gap (112), a position where a center of the transverse air gap (112) coincides with a center of the longitudinal air gap (111) is a central position of the cross air gap, and the fluxgate sensing circuit is located at the central position of the cross air gap.

7. The current sensor according to any one of claims 1-6, wherein the current sensor comprises a housing formed with a central axial bore through which the primary current conductor passes, and the housing comprises a housing body (51) and a housing cover (52), the housing body (51) and the housing cover (52) being connected and defining an enclosed space in which the electromagnet assembly (1) and the circuit board assembly (2) are mounted, and the electromagnet assembly (1) is arranged coaxially with the central axial bore.

8. Current sensor according to claim 7, characterized in that the current sensor comprises an inner shield ring (3) and an outer shield ring (4) arranged in the enclosed space and coaxially to the central shaft bore, the electromagnet assembly (1) being arranged between the inner shield ring (3) and the outer shield ring (4).

9. The current sensor according to claim 8, wherein the housing (51) is provided with a first shaft cylinder (512), the housing cover (52) is provided with a second shaft cylinder (522), the first shaft cylinder (512) is sleeved on the second shaft cylinder (522) and is abutted with the second shaft cylinder (522), the first shaft cylinder (512) and the second shaft cylinder (522) jointly define the central shaft hole, and the inner shielding ring (3) is sleeved on the first shaft cylinder (512);

an inner shielding ring positioning structure is arranged on the shell body (51) or the shell cover (52), and comprises a first axial positioning structure used for limiting the inner shielding ring (3) to move relative to the shell in the axial direction and a first transverse positioning structure used for limiting the inner shielding ring (3) to move relative to the shell in the transverse direction, and the transverse direction is perpendicular to the axial direction.

10. Current sensor according to claim 8, characterized in that an outer shield ring positioning structure is provided on the housing body (51) or on the housing cover (52), which outer shield ring positioning structure comprises a second axial positioning structure for limiting the outer shield ring (4) to move in axial direction relative to the housing and a second lateral positioning structure for limiting the outer shield ring (4) to move in lateral direction relative to the housing, the lateral direction being perpendicular to the axial direction.

11. Current sensor according to claim 7, characterized in that the circuit board assembly (2) comprises a PCB board (21) and an interposer board (22), the interposer board (22) being fixed on the PCB board (21) and being electrically connected to the PCB board (21), the magneto-sensitive element (23) having a back surface opposite the sensing surface, the back surface being fixed to the interposer board (22), the PCB board (21) being arranged perpendicular to the axial direction and being fixed with respect to the magnetic core (11).

12. Current sensor according to claim 11, characterized in that the electromagnetic assembly (1) comprises an insulating housing (12) encasing the magnetic core (11), the PCB board (21) being fixed to the insulating housing (12),

a magnetic core limiting structure used for limiting the magnetic core (11) to move relative to the shell (51) is formed between the insulating shell (12) and the shell (51), and a PCB limiting structure used for limiting the PCB (21) to move relative to the shell is formed between the shell and the PCB (21).

13. The current sensor according to claim 12, characterized in that the insulating housing (12) is provided with a positioning bracket (122) corresponding to the cross air gap position, the positioning bracket (122) is positioned between the PCB board (21) and the insulating housing (12) to maintain the position of the magneto-sensitive element (23) in the cross air gap, and the positioning bracket (122) is formed with a through hole for the penetration of the adaptor board (22) and the magneto-sensitive element (23).

14. The current sensor according to claim 7, wherein the circuit board assembly (2) comprises a current input pin (24) and a signal output pin (25), one end of the current input pin (24) and the signal output pin (25) are fixed on the PCB (21) to be electrically connected with the magnetic sensing element (23).