CN116735937A - Shunt resistor and current sensor - Google Patents
Shunt resistor and current sensor Download PDFInfo
- Publication number
- CN116735937A CN116735937A CN202310754944.7A CN202310754944A CN116735937A CN 116735937 A CN116735937 A CN 116735937A CN 202310754944 A CN202310754944 A CN 202310754944A CN 116735937 A CN116735937 A CN 116735937A
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- voltage sampling
- resistor
- current
- sampling nodes
- shunt resistor
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- 238000005070 sampling Methods 0.000 claims abstract description 87
- 238000001514 detection method Methods 0.000 claims abstract description 25
- 238000005259 measurement Methods 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R15/00—Details of measuring arrangements of the types provided for in groups G01R17/00 - G01R29/00, G01R33/00 - G01R33/26 or G01R35/00
- G01R15/14—Adaptations providing voltage or current isolation, e.g. for high-voltage or high-current networks
- G01R15/146—Measuring arrangements for current not covered by other subgroups of G01R15/14, e.g. using current dividers, shunts, or measuring a voltage drop
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R19/00—Arrangements for measuring currents or voltages or for indicating presence or sign thereof
- G01R19/0092—Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01C—RESISTORS
- H01C1/00—Details
- H01C1/14—Terminals or tapping points or electrodes specially adapted for resistors; Arrangements of terminals or tapping points or electrodes on resistors
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
Abstract
The invention provides a shunt resistor and a current sensor, wherein a plurality of voltage sampling nodes are respectively arranged at two ends of a resistance element of the shunt resistor at intervals, the voltage sampling nodes at the two ends are in one-to-one correspondence to form a plurality of current sampling paths, and the voltage sampling nodes are arranged at intervals so as to be led out respectively. The shunt resistor and the current sensor provided by the invention have a plurality of current sampling paths for current detection of the resistor element, so that the voltage of the plurality of current sampling paths is convenient to average, when the bolt mounting torque of the shunt resistor deviates from the preset value, the increment and decrement of the detection voltage of each current sampling path can be offset to a certain extent, the deviation between the actual voltage detection value and the ideal voltage detection value is reduced, the deviation of the current detection value corresponding to the voltage detection value is further reduced, and the current detection precision is improved.
Description
Technical Field
The invention relates to the technical field of electrical sensors, in particular to a shunt resistor and a current sensor.
Background
At present, the current sensor mainly comprises a Hall type current sensor and a shunt resistance type current sensor.
The Hall type current sensor is used for non-contact measurement, and can measure a larger current value by indirectly measuring the current in a lead through measuring the magnetic field intensity near the current, but the measurement accuracy is low and the temperature drift is large.
The shunt resistor type current sensor is connected in series in a loop, the current in a lead is indirectly measured by measuring the voltage at two ends of the shunt resistor, in the shunt resistor type current sensor, the shunt resistor comprises a resistor element with a preset resistance value and terminals arranged at two ends of the resistor element, the terminals are provided with assembly holes, the shunt resistor is integrally pressed and fixed onto a printed circuit board through the assembly holes by bolts, two ends of the resistor element are respectively provided with a voltage sampling node, and the current information flowing through the resistor element is obtained through the voltage information of the voltage sampling nodes.
The impedance characteristics of the resistance element in the shunt resistor are affected by the fastening degree of the bolts, and if the installation torque of each bolt does not meet the preset requirement or vibration causes the bolt to withdraw torque, the impedance distribution in the resistance element is changed, so that the current density between preset voltage sampling nodes is changed, the current flowing through the voltage sampling nodes is caused to deviate, and the final measurement deviation is caused.
Disclosure of Invention
Based on this, an object of the present invention is to provide a shunt resistor and a current sensor to reduce the influence of the mounting torque of a bolt on measurement and to improve the measurement reliability.
In one aspect, the present invention provides a shunt resistor comprising a longitudinally-distributed resistive element and two terminals, wherein,
the terminals extend out from two ends of the resistor element, and at least two assembly holes are transversely formed in each terminal;
the first end of the resistor element is provided with at least two first voltage sampling nodes which are distributed at intervals, the second end of the resistor element is provided with at least two second voltage sampling nodes which are distributed at intervals, the number of the first voltage sampling nodes is equal to that of the second voltage sampling nodes, and the first voltage sampling nodes and the second voltage sampling nodes are symmetrically arranged relative to the resistor element one by one so as to form at least two current detection paths in the resistor element.
Optionally, the first voltage sampling nodes are uniformly spaced along the lateral direction.
Optionally, the assembly holes on the two terminals are arranged symmetrically relative to the resistor element, two assembly holes are arranged on each terminal, and four first voltage sampling nodes are arranged.
According to another aspect of the present invention, there is provided a current sensor including: a shunt resistor and a subtraction circuit provided on the printed circuit board, wherein,
the shunt resistor comprises a resistance element and two terminals which are longitudinally distributed, the terminals extend out from two ends of the resistance element, at least two assembly holes are transversely arranged in each terminal, and the shunt resistor is fixed to the printed circuit board through bolts and the terminals;
the first end of the resistance element is provided with at least two first voltage sampling nodes at intervals, the second end of the resistance element is provided with at least two second voltage sampling nodes at intervals, and the first voltage sampling nodes and the second voltage sampling nodes are equal in number and are symmetrically arranged relative to the resistance element one by one so as to form at least two current detection paths in the resistance element;
the first voltage sampling node is connected to the first input end of the subtracting circuit in parallel, and the second voltage sampling node is connected to the second input end of the subtracting circuit in parallel;
the current sensor provides a first current sense signal at an output of the subtraction circuit that characterizes the magnitude of the current flowing through the shunt resistor.
Optionally, the current sensor is further provided with an analog-to-digital converter, an input end of the analog-to-digital converter is connected to an output end of the subtracting circuit, and the current sensor is used for providing a second current sensing signal representing the current flowing through the shunt resistor at the output end of the analog-to-digital converter.
Optionally, the subtracting circuit includes: an operational amplifier, a first resistor, a second resistor, and a plurality of access resistors, wherein,
the first resistor is connected between the negative input end and the output end of the operational amplifier;
the second resistor is connected between the positive input end of the operational amplifier and ground;
the first voltage sampling nodes are respectively connected to the negative input end of the operational amplifier through the access resistor;
the second voltage sampling nodes are respectively connected to the positive input end of the operational amplifier through the access resistor;
the resistance value of each access resistor is the same.
Optionally, the first voltage sampling nodes are uniformly spaced along the lateral direction.
Optionally, the assembly holes on the two terminals are arranged symmetrically relative to the resistor element, two assembly holes are arranged on each terminal, and four first voltage sampling nodes are arranged.
The shunt resistor is provided with four or more assembly holes, at least two first voltage sampling nodes and at least two second voltage sampling nodes are respectively arranged at two ends of a resistor element, so that more than two current sampling paths are constructed in the resistor element, when the uniformity of the internal resistance distribution of the resistor element is changed due to the deviation of bolt mounting torque, the distribution density of total current on different current paths is transferred, the current on each current path is changed or increased or decreased, and the voltage on the two ends of each current detection path is correspondingly increased or decreased.
The current sensor provided by the invention is provided with the shunt resistor and the subtracting operation circuit on the printed circuit board, voltage sampling nodes at two ends of the resistance element of the shunt resistor are respectively connected in parallel to two input ends of the subtracting operation circuit, the output signal corresponding to the subtracting operation circuit is the average value of the voltages on each current detection path of the resistance element, the current increment and the current decrement on different current detection paths can be mutually offset to a certain extent, the influence of current density offset caused by the offset of the mounting torque of the bolt on the current detection accuracy is reduced, and the reliability of the current detection is improved.
Drawings
FIG. 1 is a schematic diagram of a shunt resistor according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a portion of a current sensor according to an embodiment of the invention.
Description of main reference numerals: the resistor element 10, the terminal 20, the lead-out area 30, the assembly hole 21, the first voltage sampling node 31, the second voltage sampling node 32, the subtracting circuit 01, the operational amplifier U1, the first resistor R1, the second resistor R2, the access resistor R3 and the analog-to-digital converter 02.
The invention will be further described in the following detailed description in conjunction with the above-described figures.
Detailed Description
In order that the invention may be readily understood, a more complete description of the invention will be rendered by reference to the appended drawings. Several embodiments of the invention are presented in the figures. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
It will be understood that when an element is referred to as being "mounted" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "left," "right," and the like are used herein for illustrative purposes only.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, a shunt resistor according to an embodiment of the present invention is provided with a resistor element 10 having a set resistance value, two terminals 20 are provided at two ends of the resistor element 10 along a longitudinal direction, the terminals 20 are fixedly connected with the resistor element 10, and mounting holes 21 are provided on the terminals 20 to fix the terminals 20 to a printed circuit board by bolts, thereby fixing the resistor element 10.
A plurality of first voltage sampling nodes 31, a plurality of second voltage sampling nodes 32 and a lead-out area 30 are arranged at two ends of the resistor element 10, the first voltage sampling nodes 31 and the second voltage sampling nodes 32 are attached to the tail ends of the resistor element 10 and led out from the lead-out area 30 to obtain potential differences at two ends of the resistor element 10, and then the current flowing through the resistor element 10 can be obtained according to the set resistance value and ohm law of the resistor element 10.
In this embodiment, two assembly holes 21 are provided on each terminal 20 along the transverse direction, and the assembly holes 21 at two ends of the resistor element 10 are symmetrically arranged with respect to the resistor element 10, so that when the bolt mounting torques received by the assembly holes 21 are the same, the stress of the resistor element 10 is uniform, the internal impedance of the resistor element 10 is uniformly distributed in the transverse direction and the longitudinal direction, and the voltage on each current detection path can accurately represent the current flowing through the resistor element 10.
In this embodiment, four first voltage sampling nodes 31 and four second voltage sampling nodes 32 are respectively arranged at intervals and are arranged in a one-to-one symmetrical manner with respect to the resistive element 10, so that the first voltage sampling nodes 31 to the second voltage sampling nodes 32 are collinear in the longitudinal direction, a current detection path is formed between a pair of sub-nodes corresponding to the first voltage sampling nodes 31 and the second voltage sampling nodes 32, the current detection path is parallel to a standard current path (a shunt resistor integral input/output path), and the voltage correspondence acquired by the first voltage sampling nodes 31 and the second voltage sampling nodes 32 is ensured.
When the bolt mounting torques received by the respective mounting holes 21 are the same, the current distribution in the resistive element 10 is uniform, and the voltage difference signal detected on each current detection path can accurately represent the magnitude of the current flowing through the resistive element 10.
The sub-nodes of the first voltage sampling node 31 and the second voltage sampling node 32 are led out respectively, so as to obtain the voltage magnitude on each current sampling path, so as to obtain the current magnitude on each current sampling path.
When the bolt installation torque corresponding to each assembly hole deviates from the preset value, the internal impedance distribution of the resistor element 10 is changed, so that the current on each current sampling path deviates from the preset value, the total current is unchanged, the current density is transferred, the current on part of the current sampling paths is smaller than the ideal value, part of the current is larger than the ideal value, the potential difference between the corresponding voltage sampling nodes is smaller than the ideal value, and part of the potential difference between the corresponding voltage sampling nodes is larger than the ideal value.
In this embodiment, four sets of voltage sampling nodes are correspondingly arranged in the shunt resistors corresponding to the four assembly holes, and the first voltage sampling nodes 31 and the second voltage sampling nodes 32 are aligned and matched in a longitudinal direction one by one and are uniformly distributed at intervals in a transverse direction. In an alternative embodiment, at least two groups of voltage sampling nodes are provided, and the specific number can be specifically selected according to factors such as actual requirements, production limits and the like.
The input end and the output end of the shunt resistor are, for example, two lead-out areas 30 or two terminals 20, and two ends of the resistor element are parallel to the input end and the output end, so that symmetry of input current is ensured.
Referring to fig. 2, a schematic diagram of a portion of a current sensor according to an embodiment of the present invention is shown, where the current sensor of the present embodiment is provided with the shunt resistor, the subtracting circuit 01 and the analog-to-digital converter 02 provided by the present invention on a printed circuit board.
Each sub-node of the first voltage sampling node 31 is connected in parallel to a first input terminal of the subtracting circuit 01, each sub-node of the second voltage sampling node 32 is connected in parallel to a second input terminal of the subtracting circuit 01, subtracting processing of an average value of each sub-node voltage of the first voltage sampling node 31 and an average value of each sub-node voltage of the second voltage sampling node 32 is realized as a whole, and the first current sensing signal OUT1 after averaging processing is obtained by the subtracting circuit 01.
The analog-to-digital converter 02 converts the first current sensing signal OUT1 into the second current sensing signal OUT2, wherein the first current sensing signal OUT1 is an analog signal, i.e. the magnitude of the current flowing through the shunt resistor can be represented, and in analog circuit control, the analog signal can be directly used as a control signal of the system, and the first current sensing signal is taken as the final output; in the digital circuit, the second current sensing signal OUT2 is used as the final output, or the first current sensing signal OUT1 is used as the final output, and an analog-to-digital converter arranged in the digital circuit is used for converting the second current sensing signal OUT2 into a digital signal, so that digital control is realized. I.e. the analog-to-digital converter 02 may be selectively configured according to specific requirements.
In the present embodiment, the subtracting circuit 01 includes an operational amplifier U1, a first resistor R1, a second resistor R2, and eight access resistors R3.
The first resistor R1 is connected between the negative input end and the output end of the operational amplifier U1, the second resistor R2 is connected between the positive input end and the ground of the operational amplifier U1, each sub-node of the first voltage sampling node 31 is connected to the negative input end of the operational amplifier U1 through one access resistor R3, each sub-node of the second voltage sampling node 32 is connected to the positive input end of the operational amplifier U1 through one access resistor R3, the resistance values of the first resistor R1, the second resistor R2 and the eight access resistors R3 are equal, the voltage value VOUT 1=v2-v1 of the first current sensing signal OUT1 output by the operational amplifier U1 is the positive input end voltage of the operational amplifier U1, and V1 is the negative input end voltage of the operational amplifier U1.
The shunt resistor is provided with four or more assembly holes, at least two first voltage sampling nodes and at least two second voltage sampling nodes are respectively arranged at two ends of a resistor element, so that more than two current sampling paths are constructed in the resistor element, when the uniformity of the internal resistance distribution of the resistor element is changed due to the deviation of bolt mounting torque, the distribution density of total current on different current paths is transferred, the current on each current path is changed or increased or decreased, and the voltage on the two ends of each current detection path is correspondingly increased or decreased.
The current sensor provided by the invention is provided with the shunt resistor and the subtracting operation circuit on the printed circuit board, voltage sampling nodes at two ends of the resistance element of the shunt resistor are respectively connected in parallel to two input ends of the subtracting operation circuit, the output signal corresponding to the subtracting operation circuit is the average value of the voltages on each current detection path of the resistance element, the current increment and the current decrement on different current detection paths can be mutually offset to a certain extent, the influence of current density offset caused by the offset of the mounting torque of the bolt on the current detection accuracy is reduced, and the reliability of the current detection is improved.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
The foregoing examples illustrate only a few specific embodiments of the invention, which are described in greater detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.
Claims (8)
1. A shunt resistor is characterized by comprising a longitudinally distributed resistance element and two terminals, wherein,
the terminals extend out from two ends of the resistor element, and at least two assembly holes are transversely formed in each terminal;
the first end of the resistor element is provided with at least two first voltage sampling nodes which are distributed at intervals, the second end of the resistor element is provided with at least two second voltage sampling nodes which are distributed at intervals, the number of the first voltage sampling nodes is equal to that of the second voltage sampling nodes, and the first voltage sampling nodes and the second voltage sampling nodes are symmetrically arranged relative to the resistor element one by one so as to form at least two current detection paths in the resistor element.
2. The shunt resistor according to claim 1, wherein said first voltage sampling nodes are uniformly spaced apart along the lateral direction.
3. The shunt resistor according to claim 2, wherein the fitting holes on both of said terminals are arranged in one-to-one symmetry with respect to said resistive element, two of said fitting holes are provided on each of said terminals, and four of said first voltage sampling nodes are provided.
4. A current sensor, comprising: a shunt resistor and a subtraction circuit provided on the printed circuit board, wherein,
the shunt resistor comprises a resistance element and two terminals which are longitudinally distributed, the terminals extend out from two ends of the resistance element, at least two assembly holes are transversely arranged in each terminal, and the shunt resistor is fixed to the printed circuit board through bolts and the terminals;
the first end of the resistance element is provided with at least two first voltage sampling nodes at intervals, the second end of the resistance element is provided with at least two second voltage sampling nodes at intervals, and the first voltage sampling nodes and the second voltage sampling nodes are equal in number and are symmetrically arranged relative to the resistance element one by one so as to form at least two current detection paths in the resistance element;
the first voltage sampling node is connected to the first input end of the subtracting circuit in parallel, and the second voltage sampling node is connected to the second input end of the subtracting circuit in parallel;
the current sensor provides a first current sense signal at an output of the subtraction circuit that characterizes the magnitude of the current flowing through the shunt resistor.
5. The current sensor of claim 4, further comprising an analog-to-digital converter having an input connected to an output of the subtraction circuit, the current sensor providing a second current sense signal at the output of the analog-to-digital converter that is representative of the magnitude of the current flowing through the shunt resistor.
6. The current sensor according to claim 4, wherein the subtraction circuit includes: an operational amplifier, a first resistor, a second resistor, and a plurality of access resistors, wherein,
the first resistor is connected between the negative input end and the output end of the operational amplifier;
the second resistor is connected between the positive input end of the operational amplifier and ground;
the first voltage sampling nodes are respectively connected to the negative input end of the operational amplifier through the access resistor;
the second voltage sampling nodes are respectively connected to the positive input end of the operational amplifier through the access resistor;
the resistance value of each access resistor is the same.
7. The current sensor of claim 4, wherein the first voltage sampling nodes are uniformly spaced apart along the lateral direction.
8. The current sensor according to claim 7, wherein the fitting holes on both the terminals are arranged in one-to-one symmetry with respect to the resistive element, two of the fitting holes are provided on each of the terminals, and four of the first voltage sampling nodes are provided.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310754944.7A CN116735937A (en) | 2023-06-21 | 2023-06-21 | Shunt resistor and current sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310754944.7A CN116735937A (en) | 2023-06-21 | 2023-06-21 | Shunt resistor and current sensor |
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| Publication Number | Publication Date |
|---|---|
| CN116735937A true CN116735937A (en) | 2023-09-12 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202310754944.7A Pending CN116735937A (en) | 2023-06-21 | 2023-06-21 | Shunt resistor and current sensor |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117554677A (en) * | 2024-01-11 | 2024-02-13 | 武汉嘉晨电子技术有限公司 | Current sensor |
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2023
- 2023-06-21 CN CN202310754944.7A patent/CN116735937A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117554677A (en) * | 2024-01-11 | 2024-02-13 | 武汉嘉晨电子技术有限公司 | Current sensor |
| CN117554677B (en) * | 2024-01-11 | 2024-04-23 | 武汉嘉晨电子技术有限公司 | Current sensor |
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