CN114200188A - Bidirectional current detection device and method for switching device and intelligent switch - Google Patents
Bidirectional current detection device and method for switching device and intelligent switch Download PDFInfo
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Abstract
The invention discloses a bidirectional current detection device and method for a switch device and an intelligent switch, wherein the device comprises: the magnetic shielding assembly and the Hall detection assembly are arranged in the magnetic shielding assembly; the Hall detection assembly comprises a Hall element body, a zero setting circuit, a forward acquisition branch and a reverse acquisition branch; the Hall element body is used for collecting bidirectional current and outputting forward sampling voltage and reverse sampling voltage; the zero setting circuit is used for providing zero setting voltage for the forward acquisition branch and the reverse acquisition branch; the forward acquisition branch is used for outputting forward detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage; the reverse acquisition branch is used for outputting reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage. According to the invention, the Hall element and the zero setting circuit are integrated on the switch device through the magnetic shielding assembly, so that the zero point unbalance of the bidirectional circuit detection is reduced, and the bidirectional current detection precision and the electromagnetic compatibility are improved.
Description
Technical Field
The invention relates to the technical field of Hall sensors, in particular to a bidirectional current detection device and method for a switching device and an intelligent switch.
Background
The bidirectional electromagnetic relay is a new electronic switch device composed of solid-state electrons, and integrates an optical coupler, a high-power bidirectional thyristor, a trigger circuit and a resistance-capacitance absorption loop into a whole, and can be used for remotely switching on/off an AC/DC circuit.
However, the bidirectional electromagnetic relay itself does not have a current detection function, and it is difficult to satisfy the requirement of intelligent protection, and the current flowing through the bidirectional electromagnetic relay can be detected by adding a current detection protection device, and the on/off of the bidirectional electromagnetic relay can be controlled according to the detected current value.
The existing current detection protection device usually adopts a series sampling resistor or a Hall sensor as a current detection device, the Hall sensor carries out isolation detection on current based on a non-contact Hall sensing mode, and in actual use, the current detection protection device has the following problems: the application scene of the relay generally relates to larger electromagnetic interference, and the existing open-loop Hall sensor can not meet the electromagnetic compatibility requirement, easily causes detection errors and reduces the current detection precision. In addition, the hall element has unbalanced voltage output characteristics, and zero point offset can cause low current detection accuracy to be reduced, and the requirement of high-accuracy current detection is not met.
Disclosure of Invention
The invention provides a bidirectional current detection device and method for a switching device and an intelligent switch, which are used for realizing high-precision detection of bidirectional current of the switching device, reducing the unbalance of two paths of output when a Hall element is at a zero point and achieving high electromagnetic compatibility.
In a first aspect, an embodiment of the present invention provides a bidirectional current detection apparatus for a switching device, where the switching device is provided with a wiring portion, and the bidirectional current detection apparatus includes: the magnetic shielding assembly is of a hollow structure and is sleeved on the wiring part; the Hall detection assembly comprises a Hall element body, a zero setting circuit and a positive and negative bidirectional acquisition circuit, wherein the positive and negative bidirectional acquisition circuit is provided with a positive acquisition branch and a negative acquisition branch; the Hall element body is used for collecting bidirectional current and outputting forward sampling voltage and reverse sampling voltage; the zero setting circuit is used for providing zero adjustment voltage for the forward acquisition branch and the reverse acquisition branch, and the zero adjustment voltage is used for adjusting zero current detection voltage of the forward acquisition branch and the reverse acquisition branch; the forward acquisition branch is used for outputting a forward detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage; the reverse acquisition branch is used for outputting reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage.
Optionally, a minimum voltage value of the forward detection voltage and the reverse detection voltage is greater than a zero-current hall voltage value of the hall element body.
Optionally, the zeroing circuit is provided with a voltage follower, a first zeroing branch and a second zeroing branch, an input end of the voltage follower is electrically connected with a power supply, an output end of the voltage follower is electrically connected with the first zeroing branch and the second zeroing branch, and the voltage follower is configured to provide a power supply voltage for the first zeroing branch and the second zeroing branch; the first zero-setting branch circuit is used for providing a first zero-crossing point adjusting voltage for the forward acquisition branch circuit; the second zero-crossing point adjusting branch is used for providing a second zero-crossing point adjusting voltage for the reverse collecting branch; the first zero-crossing point adjusting voltage and the second zero-crossing point adjusting voltage satisfy: when the current collected by the Hall element body is zero, the forward detection voltage is equal to or approximately equal to the reverse detection voltage.
Optionally, the first zero adjustment branch is provided with at least two voltage dividing resistors and a first voltage dividing node connected in series, and the first voltage dividing node is configured to output a first zero-crossing point adjustment voltage; the second zero adjustment branch is provided with at least two voltage division resistors and a second voltage division node which are connected in series, and the second voltage division node is used for outputting a second zero crossing point adjustment voltage.
Optionally, the hall sensing assembly further comprises: the temperature detection unit is arranged adjacent to the Hall element body and used for acquiring the real-time temperature of the Hall element body and sending the real-time temperature to the temperature compensation unit; the temperature compensation unit is used for determining bias compensation current according to the real-time temperature and compensating the current collected by the Hall element body according to the bias compensation current.
Optionally, the magnetic shielding assembly comprises a magnetic shielding outer shell made of a non-ferromagnetic material and a magnetic shielding base, the magnetic shielding outer shell is provided with at least one wire outlet hole, and the wire outlet hole is used for leading out a wire; the magnetic shielding base is provided with an ear-shaped fastening structure, and the ear-shaped fastening structure is used for fixedly mounting the bidirectional current detection device on the switch device.
Optionally, a magnetic ring frame and a distributed multi-air-gap magnetic ring arranged in the magnetic ring frame are further arranged in the magnetic shielding assembly; the magnetic ring frame is of a hollow circular ring structure, a plurality of symmetrically distributed groove structures are arranged in the magnetic ring frame, and an air gap is arranged between every two adjacent groove structures; the multi-air-gap magnetic ring comprises a plurality of identical distributed magnetic cores, and the magnetic cores are arranged in the groove structures in a one-to-one correspondence manner; the Hall element body is embedded in the air gap and used for collecting a bidirectional magnetic field in the air gap.
Optionally, the hall detection assembly further includes a printed circuit board, and the printed circuit board is provided with a routing line, and the routing line is used for electrically connecting the hall element body, the zero setting circuit and the forward and backward bidirectional collecting circuit; the printed circuit board, the magnetic shielding assembly and the magnetic ring frame are provided with anti-displacement structures.
In a second aspect, an embodiment of the present invention further provides a bidirectional current detection method for a switching device, where the method is used for the bidirectional current detection apparatus, and the method includes the following steps:
determining a zero point adjusting voltage based on the zero point drift voltage of the Hall element body;
acquiring a forward sampling voltage and a reverse sampling voltage of the Hall element body for acquiring bidirectional current output;
and outputting forward detection voltage or reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage.
In a third aspect, an embodiment of the present invention further provides an intelligent switch, including: the bidirectional current detection device is sleeved on any wiring part of the switch body.
The invention provides a bidirectional current detection device and method for a switch device and an intelligent switch, wherein the current detection device is provided with a magnetic shielding assembly and a Hall detection assembly arranged in the magnetic shielding assembly, and the magnetic shielding assembly is of a hollow structure and is sleeved on a wiring part; the Hall detection assembly is provided with a Hall element body, a zero setting circuit, a forward collecting branch and a reverse collecting branch, wherein the Hall element body is used for collecting bidirectional current and outputting forward sampling voltage and reverse sampling voltage; the zero setting circuit is used for providing zero setting voltage for the forward acquisition branch and the reverse acquisition branch; the forward acquisition branch is used for outputting forward detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage; the reverse acquisition branch circuit is used for outputting reverse detection voltage according to forward sampling voltage, reverse sampling voltage and zero point regulation voltage, and integrates a Hall element and a zero point regulation circuit in a switch device through a magnetic shielding assembly, so that the problem of low bidirectional current detection precision of the existing Hall sensor is solved, zero point unbalance of bidirectional circuit detection is reduced, bidirectional current detection precision and electromagnetic compatibility are improved, the circuit is simple, the miniaturized design can be realized, and the reliability is high.
Drawings
Fig. 1 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to a second embodiment of the present invention;
fig. 3 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to a third embodiment of the present invention;
fig. 4 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to a fourth embodiment of the present invention;
fig. 5 is a flowchart of a bidirectional current detection method for a switching device according to a fifth embodiment of the present invention;
fig. 6 is a schematic structural diagram of an intelligent switch according to a sixth embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Example one
Fig. 1 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to an embodiment of the present invention.
In this embodiment, the switching device may be a relay or a contactor having a bidirectional conduction function, the switching device is provided with a wiring portion, and the bidirectional current detection apparatus realizes current detection by detecting a current flowing through the wiring portion.
As shown in fig. 1, the switching device bidirectional current detection apparatus 00 includes: the magnetic shielding component 1 is of a hollow structure, and the magnetic shielding component 1 is sleeved on the wiring part; the Hall detection assembly comprises a Hall element body 210, a zero setting circuit 220 and a positive and negative bidirectional acquisition circuit 230, wherein the positive and negative bidirectional acquisition circuit 230 is provided with a positive acquisition branch 231 and a negative acquisition branch 232; the Hall element body 210 is used for collecting bidirectional current and outputting forward sampling voltage U1+ and reverse sampling voltage U1-; the zero setting circuit 220 is configured to provide a zero setting voltage to the forward collecting branch 231 and the reverse collecting branch 232, where the zero setting voltage is used to adjust a zero current detection voltage of the forward collecting branch 231 and the reverse collecting branch 232; the forward collecting branch 231 is used for outputting a forward detection voltage Z1 according to a forward sampling voltage U1+, a reverse sampling voltage U1-and a zero point regulation voltage; the reverse acquisition branch 232 is used for outputting a reverse detection voltage F1 according to the forward sampling voltage U1+, the reverse sampling voltage U1-and the zero point regulation voltage.
Referring to fig. 1, the forward collecting branch 231 includes a first operational amplifier U01, an inverting input terminal of the first operational amplifier U01 receives a forward sampling voltage U1+ output by the hall element body 210 through a first resistor R1, a non-inverting input terminal of the first operational amplifier U01 receives an inverted sampling voltage U1-output by the hall element body 210 through a second resistor R2, the non-inverting input terminal of the first operational amplifier U01 also receives a zero point adjusting voltage provided by the zeroing circuit 220 through a third resistor R3, and a seventh resistor R7 is connected between the inverting input terminal and an output terminal of the first operational amplifier U01; the backward collecting branch 232 comprises a second operational amplifier U02, the inverting input terminal of the second operational amplifier U02 receives the backward sampling voltage U1 output by the hall element body 210 through a fourth resistor R4, the non-inverting input terminal of the second operational amplifier U02 receives the forward sampling voltage U1 output by the hall element body 210 through a fifth resistor R5, the non-inverting input terminal of the second operational amplifier U02 also receives the zero point adjusting voltage provided by the zero point adjusting circuit 220 through a sixth resistor R6, an eighth resistor R8 is connected between the inverting input terminal and the output terminal of the second operational amplifier U02, and the first operational amplifier U01 samples the voltage U1+ according to the forward sampling voltage U1+, the reverse sampling voltage U1 & lt- & gt and the zero point regulation voltage output forward detection voltage Z1, and the second operational amplifier U02 is used for amplifying the voltage difference between the forward sampling voltage U1 & lt + & gt and the reverse sampling voltage U1 & lt- & gt; the second operational amplifier U02 outputs a reverse detection voltage F1 according to the forward sampling voltage U1+, the reverse sampling voltage U1-and a zero point adjusting voltage, the second operational amplifier U02 is used for amplifying the voltage difference between the forward sampling voltage U1+ and the reverse sampling voltage U1-, and the amplification factor can be adjusted by adjusting the resistance values of the first resistor R1 to the eighth resistor R8.
Referring to fig. 1, the forward collecting branch 231 and the reverse collecting branch 232 are further adaptively provided with a filtering and voltage stabilizing circuit for improving the stability of the detection output signal.
Specifically, before the bidirectional current detection, the zero adjustment circuit 220 adjusts the zero adjustment voltage provided by the forward collecting branch 231 and the reverse collecting branch 232, so that the zero current detection voltages of the forward collecting branch 231 and the reverse collecting branch 232 tend to be consistent, and the magnitude of the zero current detection voltage of the forward collecting branch 231 and the reverse collecting branch 232 can be determined based on the zero drift voltage of the hall element body 210.
In the double-current detection process, the magnetic shielding component 1 internally packaged with the Hall detection component is sleeved on a wiring part of a switch device, the Hall element body 210 senses the change of a magnetic field through the Hall effect principle and outputs a forward sampling voltage U1+ and a reverse sampling voltage U1-, if a forward current flows through the wiring part of the switch device, the forward sampling voltage U1+ is greater than the reverse sampling voltage U1-, a forward acquisition branch 231 amplifies a voltage difference between the forward sampling voltage U1+ and the reverse sampling voltage U1-, outputs a forward detection voltage Z1, the output of a second operational amplifier U02 is clamped at 0V, and the voltage slightly higher than 0V is output under the influence of a zero point regulation voltage; when a reverse current flows through the connection portion of the switching device, the forward sampled voltage U1+ is smaller than the reverse sampled voltage U1-, and the outputs of the first operational amplifier U01 and the second operational amplifier U02 are opposite to the above case. The magnitude and direction of the current flowing through the terminal portion of the switching device are obtained by the forward sense voltage Z1 and the reverse sense voltage F1. The magnetic shielding assembly integrates the Hall element and the zero setting circuit into the switch device, the problem that the two-way current detection precision of the existing Hall sensor is low is solved, the zero point unbalance of the two-way circuit detection is reduced, the two-way current detection precision is improved, the output error caused by residual magnetism when the two-way current detection is reduced through the magnetic shielding assembly, the electromagnetic compatibility and the small current detection precision are improved, the circuit is simple, the miniaturized design can be realized, and the reliability is high.
Alternatively, the minimum voltage values of the forward detection voltage and the reverse detection voltage are greater than the zero-current hall voltage value of the hall element body 210.
The zero current hall voltage value is a hall voltage value output by the hall element body 210 when the current collected by the hall element body 210 is zero. Illustratively, the zero-current hall voltage value of the hall element body 210 may be tens of millivolts.
Illustratively, the minimum voltage value of the forward detection voltage and the reverse detection voltage may be set to be 0.1V, that is, the zero setting circuit 220 provides a lifting voltage to the forward collecting branch 231 and the reverse collecting branch 232, so that when the current collected by the hall element body 210 is zero, the forward detection voltage outputs a 0.1V detection voltage, and the reverse detection voltage outputs a 0.1V detection voltage.
Optionally, fig. 2 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to a second embodiment of the present invention, and on the basis of fig. 1, a structure of a zeroing circuit is exemplarily shown.
As shown in fig. 2, the zeroing circuit 220 is provided with a voltage follower 221, a first zeroing branch 222 and a second zeroing branch 223, an input end of the voltage follower is electrically connected to the power supply VDD, an output end of the voltage follower 221 is electrically connected to the first zeroing branch 222 and the second zeroing branch 223, and the voltage follower 221 is configured to provide a power supply voltage to the first zeroing branch 222 and the second zeroing branch 223; the first zero adjustment branch 222 is configured to provide a first zero-crossing adjustment voltage to the forward direction collection branch 231; the second zero adjustment branch 223 is configured to provide a second zero-crossing adjustment voltage to the reverse acquisition branch 232; the first zero-crossing point adjusting voltage and the second zero-crossing point adjusting voltage meet the following conditions: when the current collected by the hall element body 210 is zero, the forward detection voltage and the reverse detection voltage are equal or approximately equal.
In one embodiment, the power supply VDD can be used to provide DC +200mv power.
Optionally, the first zero adjustment branch 222 is provided with at least two voltage dividing resistors and a first voltage dividing node connected in series, and the first voltage dividing node is configured to output a first zero-crossing point adjustment voltage; the second zero adjustment branch 223 is provided with at least two voltage dividing resistors and a second voltage dividing node which are connected in series, and the second voltage dividing node is used for outputting a second zero-crossing point adjustment voltage.
Referring collectively to fig. 2, the first zeroing branch 222 includes a first voltage dividing resistor R10, a second voltage dividing resistor R11, and a third voltage dividing resistor R11 connected in seriesThe voltage dividing resistor R12 and the second zeroing branch 223 include a fourth voltage dividing resistor R20, a fifth voltage dividing resistor R21 and a sixth voltage dividing resistor R22 connected in series, and if the supply voltage provided by the power supply VDD is defined as V1, the first zero-crossing point adjusting voltage V1' satisfies:
the second zero-crossing point adjustment voltage V1 ″ satisfies:
specifically, before the bidirectional current detection, a first potentiometer and a second potentiometer may be disposed between the output end of the voltage follower 221 and the ground end, a first zero-crossing point adjustment voltage V1' is output through a sliding tap of the first potentiometer, and a second zero-crossing point adjustment voltage V1 ″ is output through a sliding tap of the second potentiometer, and during the debugging process, positions of the sliding taps in the first potentiometer and the second potentiometer are adjusted multiple times, so that zero current detection voltages of the forward collecting branch 231 and the reverse collecting branch 232 tend to be consistent, a voltage division ratio when the zero current detection voltages tend to be consistent is recorded, a corresponding multi-resistor structure is set according to the voltage division ratio, and flexibility and accuracy of resistance matching are achieved through multi-resistor design.
In this embodiment, the zero-current detection voltage may be determined based on the zero-drift voltage of the hall element body 210, and the minimum voltage value of the forward detection voltage and the reverse detection voltage is ensured to be greater than the zero-current hall voltage value of the hall element body 210 when the collected current is zero by adjusting the first zero-crossing point adjustment voltage V1' and the second zero-crossing point adjustment voltage V1 ″, for example, the minimum voltage value may be 0.1V.
Optionally, fig. 3 is a schematic structural diagram of a switching device bidirectional current detection apparatus according to a third embodiment of the present invention.
As shown in fig. 3, the hall sensing assembly further includes: the temperature detection unit 240 and the temperature compensation unit 250, the temperature detection unit 240 is arranged adjacent to the hall element body 210, and the temperature detection unit 240 is used for acquiring the real-time temperature of the hall element body 210 and sending the real-time temperature to the temperature compensation unit 250; the temperature compensation unit 250 is configured to determine a bias compensation current according to the real-time temperature, and compensate the current collected by the hall element body 210 according to the bias compensation current.
The bias compensation current is a current detection deviation compensation parameter caused by the temperature drift characteristic of the hall element body 210.
In this embodiment, the temperature detecting unit 240 may be a platinum resistor.
Specifically, in the bidirectional current detection process, the temperature detection unit 240 collects real-time temperature around the hall element body 210, and if the user needs to calibrate the current detection result at high and low temperatures, the temperature compensation unit 250 determines the offset compensation current according to the real-time temperature, and adjusts the output voltage of the hall element body 210 according to the offset compensation current and the real-time detection current, which is beneficial to improving the detection error caused by the temperature drift of the hall element and improving the detection precision.
Optionally, fig. 4 is a schematic structural diagram of a bidirectional current detection apparatus for a switching device according to a fourth embodiment of the present invention, and is applicable to the bidirectional current detection apparatus according to any of the embodiments.
As shown in fig. 4, the magnetic shield assembly 1 includes a magnetic shield case 110 and a magnetic shield base 120 made of non-ferromagnetic material, the magnetic shield case 110 is provided with at least one wire outlet hole for leading out a wire; the magnetic shield base 120 is provided with an ear-shaped fastening structure for fixedly mounting the bidirectional current detecting apparatus 00 to the switching device.
In this embodiment, the magnetic shielding housing 110 and the magnetic shielding base 120 are embedded into each other to form a hollow structure, the inner diameter of the hollow structure is matched with the outer diameter of the wiring portion of the switch device, each portion of the hall detection assembly is arranged inside the hollow structure in a layered manner to form a bidirectional current detection device integrated with a package, and when the bidirectional current detection device is used, the bolt penetrates through the ear-shaped fastening structure, so that the bidirectional current detection device is fixedly installed on the installation plate of the switch device.
In one embodiment, the magnetic shielding shell 110 and the magnetic shielding base 120 can be made of a non-ferromagnetic material, typically, the non-ferromagnetic material can be an aluminum alloy, which is beneficial to output errors caused by residual magnetism during bidirectional current detection, and effectively improves the detection precision of small current; in addition, non-ferromagnetic materials such as aluminum have a good effect of shielding external electromagnetic interference, and the electromagnetic compatibility performance is effectively improved.
In one embodiment, as shown in fig. 4, a magnetic ring frame 130 and a distributed multi-air-gap magnetic ring 140 disposed in the magnetic ring frame are further disposed in the magnetic shielding assembly 1; the magnetic ring frame 130 is a hollow circular ring structure, a plurality of symmetrically distributed groove structures are arranged in the magnetic ring frame 130, and an air gap is arranged between every two adjacent groove structures; the multi-gap magnetic ring 140 includes a plurality of identical distributed magnetic cores arranged one-to-one within the groove structure.
In this embodiment, the groove structure may be a sector groove.
In this embodiment, the magnetic ring frame 130 may be a hollow circular ring structure made of a high temperature resistant non-conductive material, typically, the high temperature resistant non-conductive material may be polyimide or nylon, and the hollow circular ring structure is sleeved on the wiring portion of the switch device, the magnetic ring frame 130 has an outer shape structure of a circular-like structure with two flat edges, eight grooves having a fan-shaped structure are centrally and symmetrically distributed in the magnetic ring frame, a partition wall with a thickness of 2mm is disposed between every two adjacent fan-shaped grooves, and an air gap with a width of 2mm is disposed in the center of each of the two sides of the flat edge.
In this embodiment, the multi-gap magnetic ring 140 includes eight identical distributed magnetic cores, the magnetic cores are in a fan-shaped structure, are matched with the grooves, and are uniformly distributed in the fan-shaped grooves of the magnetic ring frame 130, and each magnetic core is formed by stacking single pieces of permalloy with the thickness of 0.5 mm.
In one embodiment, the air gap length and the current to be measured satisfy the following formula one;
wherein, B is the maximum magnetic induction intensity which can be detected by the Hall element, I is the current to be detected, N is the number of turns of the current to be detected, mu0Is the vacuum permeability and δ is the air gap length.
In this embodiment, the total number of the grooves and the air gaps is 8, and the length δ of the air gap is 16 mm. The current to be measured can reach 3000A. Through the distributed multi-air-gap structure, air-gap magnetic field divergence is prevented, measurement precision and measurement range are improved, and large current detection can be realized.
In an embodiment, as shown in fig. 4, the hall sensing assembly further includes a printed circuit board 150, and the printed circuit board 150 is provided with a trace, and the trace is used to electrically connect the hall element body 210, the zeroing circuit (not shown in fig. 4), the forward and backward bidirectional collecting circuit (not shown in fig. 4) and the temperature detecting unit 240.
As shown in fig. 4, the printed circuit board 150 is a hollow ring-shaped circuit board, on which the hall element body 210, the temperature detection unit 240 and the wires for supplying power to the hall element body 210, outputting power from the hall element body and outputting power from the temperature detection unit 240 are soldered, and the wires are led out through at least one wire outlet hole on the magnetic shielding casing 110.
As shown in fig. 4, the hall element body 210 is embedded in the air gap of the multi-air-gap magnetic ring 140, and the hall element body 210 is used for collecting a bidirectional magnetic field in the air gap.
In one embodiment, as shown in fig. 4, an annular insulating gasket 160 is disposed between the printed circuit board 150 and the multi-gap magnetic ring 140, the insulating gasket 160 may be a gasket made of nylon or epoxy resin, and the insulating gasket 160 is used to physically isolate the printed circuit board 150 from the multi-gap magnetic ring 140, so as to prevent short circuit of components on the printed circuit board 150. As shown in fig. 4, the insulating pad 160 is cut at the positions of the hall element body 210, the temperature detecting unit 240 and the conductive lines of the printed circuit board 150, so as to facilitate assembly,
as shown in fig. 4, the printed circuit board 150, the magnetic shield case 110, the magnetic shield base 120, and the magnetic ring holder 130 are provided with an anti-displacement structure. Wherein, should prevent the structure of shifting can be for the quasi-circular structure that has flat border, prevents the structure of shifting through the setting, ensures that each subassembly of magnetic shield subassembly 1 inside can not take place to rotate in the vibration environment, improves the circuit reliability.
Therefore, the bidirectional current detection device provided by the invention has the advantages that the Hall element, the unbalanced zeroing circuit and the bidirectional acquisition circuit are packaged by the annular magnetic shielding structure, so that the output error caused by residual magnetism and unbalanced voltage of the Hall element when the Hall sensor detects bidirectional current can be reduced, and the small-current bidirectional detection precision is effectively improved; by arranging the multi-air-gap magnetic core structure, the open-loop Hall current sensor is ensured to meet the requirement of large-current detection range under the requirement of smaller volume and weight; through setting up temperature acquisition circuit, can provide the data basis for the user that has high low temperature calibration demand, the miniaturized integrated level is high, and simple installation can realize two-way current measurement, and measuring range is wide, measurement accuracy is high, the interference killing feature is strong.
The fifth embodiment of the invention also provides a bidirectional current detection method for the switching device, which is realized based on the bidirectional current detection device provided by any one of the embodiments and has the beneficial effects of the device.
Fig. 5 is a flowchart of a bidirectional current detection method for a switching device according to a fifth embodiment of the present invention.
As shown in fig. 5, the detection method specifically includes the following steps:
step S1: the zero adjustment voltage is determined based on the zero drift voltage of the body of the hall element.
Step S2: and acquiring a forward sampling voltage and a reverse sampling voltage of the Hall element body for acquiring bidirectional current output.
Step S3: and outputting the forward detection voltage or the reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage.
Optionally, the minimum voltage value of the forward detection voltage and the reverse detection voltage is greater than the zero-current hall voltage value of the hall element body.
Optionally, determining the zero adjustment voltage based on the zero drift voltage of the hall element body includes: before bidirectional current detection, a first zero crossing point regulating voltage is provided for a forward acquisition branch, and a second zero crossing point regulating voltage is provided for a reverse acquisition branch; the first zero-crossing point adjusting voltage and the second zero-crossing point adjusting voltage meet the following conditions: when the current collected by the Hall element body is zero, the forward detection voltage and the reverse detection voltage are equal or approximately equal.
Optionally, the detection method further includes: collecting the real-time temperature of the Hall element body; the bias compensation current is determined according to the real-time temperature, the current collected by the Hall element body is compensated according to the bias compensation current, and a temperature collection circuit is arranged, so that data basis can be provided for users with high and low temperature calibration requirements, the detection error caused by temperature drift of the Hall element is improved, and the detection precision is improved.
Fig. 6 is a schematic structural diagram of an intelligent switch according to a sixth embodiment of the present invention.
As shown in fig. 6, the intelligent switch 100 includes: the switch body 101 and the bidirectional current detection device 00, the bidirectional current detection device 00 is sleeved on any one of the wiring portions 101A of the switch body 101 and is fixedly installed on the installation plate of the switch body 101.
In this embodiment, the intelligent switch 100 may be a relay or a contactor having a bidirectional current detection function.
In summary, the bidirectional current detection device, the bidirectional current detection method and the intelligent switch of the switch device provided by the invention have the advantages that the current detection device is provided with the magnetic shielding assembly and the hall detection assembly arranged in the magnetic shielding assembly, and the magnetic shielding assembly is of a hollow structure and is sleeved on the wiring part; the Hall detection assembly is provided with a Hall element body, a zero setting circuit, a forward collecting branch and a reverse collecting branch, wherein the Hall element body is used for collecting bidirectional current and outputting forward sampling voltage and reverse sampling voltage; the zero setting circuit is used for providing zero setting voltage for the forward acquisition branch and the reverse acquisition branch; the forward acquisition branch is used for outputting forward detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage; the reverse acquisition branch circuit is used for outputting reverse detection voltage according to forward sampling voltage, reverse sampling voltage and zero point regulation voltage, and the Hall element and the zero point regulation circuit are integrated in the switch device through the magnetic shielding assembly, so that the problem of low bidirectional current detection precision of the existing Hall sensor is solved, zero point imbalance of bidirectional circuit detection is reduced, bidirectional current detection precision and electromagnetic compatibility are improved, the circuit is simple, the miniaturized design can be realized, and the reliability is high.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A bidirectional current detecting apparatus for a switching device provided with a wiring portion, comprising: the magnetic shielding assembly is of a hollow structure and is sleeved on the wiring part;
the Hall detection assembly comprises a Hall element body, a zero setting circuit and a positive and negative bidirectional acquisition circuit, wherein the positive and negative bidirectional acquisition circuit is provided with a positive acquisition branch and a negative acquisition branch;
the Hall element body is used for collecting bidirectional current and outputting forward sampling voltage and reverse sampling voltage;
the zero setting circuit is used for providing zero adjustment voltage for the forward acquisition branch and the reverse acquisition branch, and the zero adjustment voltage is used for adjusting zero current detection voltage of the forward acquisition branch and the reverse acquisition branch;
the forward acquisition branch is used for outputting a forward detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage;
the reverse acquisition branch is used for outputting reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage.
2. The bi-directional current sensing device of claim 1, wherein a minimum voltage value of said forward sense voltage and said reverse sense voltage is greater than a zero current hall voltage value of said hall element body.
3. The bidirectional current detecting device according to claim 1, wherein the zeroing circuit is provided with a voltage follower, a first zeroing branch and a second zeroing branch, an input end of the voltage follower is electrically connected with a power supply, an output end of the voltage follower is electrically connected with the first zeroing branch and the second zeroing branch, and the voltage follower is used for providing a power supply voltage for the first zeroing branch and the second zeroing branch;
the first zero-setting branch circuit is used for providing a first zero-crossing point adjusting voltage for the forward acquisition branch circuit;
the second zero-crossing point adjusting branch is used for providing a second zero-crossing point adjusting voltage for the reverse collecting branch;
the first zero-crossing point adjusting voltage and the second zero-crossing point adjusting voltage satisfy: when the current collected by the Hall element body is zero, the forward detection voltage is equal to or approximately equal to the reverse detection voltage.
4. The bidirectional current detecting device according to claim 3, wherein the first zero adjusting branch is provided with at least two voltage dividing resistors connected in series and a first voltage dividing node for outputting a first zero-crossing adjusting voltage; the second zero adjustment branch is provided with at least two voltage division resistors and a second voltage division node which are connected in series, and the second voltage division node is used for outputting a second zero crossing point adjustment voltage.
5. The bi-directional current sensing device of claim 1, wherein said hall sensing assembly further comprises: the temperature detection unit is arranged adjacent to the Hall element body and used for acquiring the real-time temperature of the Hall element body and sending the real-time temperature to the temperature compensation unit;
the temperature compensation unit is used for determining bias compensation current according to the real-time temperature and compensating the current collected by the Hall element body according to the bias compensation current.
6. The bidirectional current detection device according to claim 1, wherein the magnetic shielding assembly comprises a magnetic shielding outer shell made of non-ferromagnetic material and a magnetic shielding base, the magnetic shielding outer shell is provided with at least one wire outlet hole, and the wire outlet hole is used for leading out a wire;
the magnetic shielding base is provided with an ear-shaped fastening structure, and the ear-shaped fastening structure is used for fixedly mounting the bidirectional current detection device on the switch device.
7. The bidirectional current detection device of claim 1, wherein a magnetic ring frame and a distributed multi-air-gap magnetic ring disposed in the magnetic ring frame are further disposed in the magnetic shielding assembly;
the magnetic ring frame is of a hollow circular ring structure, a plurality of symmetrically distributed groove structures are arranged in the magnetic ring frame, and an air gap is arranged between every two adjacent groove structures;
the multi-air-gap magnetic ring comprises a plurality of identical distributed magnetic cores, and the magnetic cores are arranged in the groove structures in a one-to-one correspondence manner;
the Hall element body is embedded in the air gap and used for collecting a bidirectional magnetic field in the air gap.
8. The bidirectional current detection device according to claim 7, wherein the hall detection assembly further comprises a printed circuit board, the printed circuit board is provided with a routing line, and the routing line is used for electrically connecting the hall element body, the zeroing circuit and the forward and backward bidirectional acquisition circuit;
the printed circuit board, the magnetic shielding assembly and the magnetic ring frame are provided with anti-displacement structures.
9. A bidirectional current detecting method for a switching device, which is used in the bidirectional current detecting apparatus according to any one of claims 1 to 8, the method comprising the steps of:
determining a zero point adjusting voltage based on the zero point drift voltage of the Hall element body;
acquiring a forward sampling voltage and a reverse sampling voltage of the Hall element body for acquiring bidirectional current output;
and outputting forward detection voltage or reverse detection voltage according to the forward sampling voltage, the reverse sampling voltage and the zero point regulation voltage.
10. An intelligent switch, comprising: the switch body and the bidirectional current detection device as claimed in any one of claims 1 to 8, wherein the bidirectional current detection device is sleeved on any one of the wiring portions of the switch body.
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