Current sensor using a coil for frequency compensation

Abstract

The present invention provides a current sensor that uses a coil for frequency compensation, which includes a current-carrying conductor, an induction coil, a magnetic sensor, and a signal processing circuit. The current-carrying conductor is used to provide a flow-through channel for the current to be measured; the induction coil is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the induction coil is called the first magnetic field; the magnetic sensor is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the magnetic sensor is called the second magnetic field; the signal processing circuit is used to perform frequency compensation on the voltage output by the magnetic sensor based on the voltage output by the induction coil to detect the current to be measured. Compared with the prior art, the present invention uses a coil for frequency compensation to improve the detection accuracy of high-frequency currents.

Description

Technical Field

[0001] The present invention relates to the technical field of current sensors, and particularly to a current sensor that uses a coil for frequency compensation.

Background Art

[0002] Current sensors for measuring the magnitude of current are widely used in various electronic devices. For current sensors, since the magnetic sensor is relatively close to the current-carrying conductor, the magnetic field generated by the current in the current-carrying conductor at the magnetic sensor depends on the frequency of the current, reducing the detection accuracy of high-frequency currents.

[0003] Therefore, it is necessary to propose a technical solution to overcome the above problems.

Summary of the Invention

[0004] One object of the present invention is to provide a current sensor that uses a coil for frequency compensation to improve the detection accuracy of high-frequency currents.

[0005] According to one aspect of the present invention, the present invention provides a current sensor, which includes a current-carrying conductor, an induction coil, a magnetic sensor, and a signal processing circuit. The current-carrying conductor is used to provide a flow channel for the current to be measured; the induction coil is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the induction coil is called the first magnetic field; the magnetic sensor is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the magnetic sensor is called the second magnetic field; the signal processing circuit is used to perform frequency compensation on the voltage output by the magnetic sensor based on the voltage output by the induction coil to detect the current to be measured.

[0006] Further, the first magnetic field does not depend on the frequency of the current in the current-carrying conductor; the second magnetic field depends on the frequency of the current in the current-carrying conductor.

[0007] Further, the distance from the induction coil to the current-carrying conductor is farther than the distance from the magnetic sensor to the current-carrying conductor; the second magnetic field is greater than the first magnetic field.

[0008] Further, the coupling coefficient of the current in the current-carrying conductor to the first magnetic field is called the first coupling coefficient; the coupling coefficient of the current in the current-carrying conductor to the second magnetic field is called the second coupling coefficient.

[0009] Further, the signal processing circuit performs the following operations: obtaining an initial test current through the voltage output by the magnetic sensor and the value of the second coupling coefficient at a predetermined frequency current; obtaining an estimated frequency of the current in the current-carrying conductor using the voltage output by the induction coil and the initial test current; obtaining a value of the second coupling coefficient at the estimated frequency current using the estimated frequency of the current in the current-carrying conductor and the dependence of the second coupling coefficient on the current frequency; obtaining a current value of the current in the current-carrying conductor through the voltage output by the magnetic sensor and the value of the second coupling coefficient at the estimated frequency current.

[0010] Furthermore, the voltage V output by the induction coil 11 =2πfμ0A(H 11 / I)I, where μ0 is the vacuum magnetic permeability, A is the area enclosed by the induction coil, H 11 / I is the first coupling coefficient, f is the frequency of the current in the current-carrying conductor, I is the current value of the current in the current-carrying conductor; the voltage V output by the magnetic sensor 12 =S[H 12 (f) / I]I, where S is the sensitivity of the magnetic sensor relative to the magnetic field, H 12 (f) / I is the second coupling coefficient, and I is the current value of the current in the current-carrying conductor.

[0011] Furthermore, the voltage V output by the magnetic sensor 12 and the value H of the second coupling coefficient at a predetermined frequency current 12 (f0) / I, the initial test current I0=V 12 / {S[H 12 (f0) / I]}, wherein f0 is the predetermined frequency of the predetermined frequency current; the voltage V output by the induction coil is 11 and the initial test current I0, the estimated frequency f of the current in the current-carrying conductor is obtained 11 / [2πμ0A(H 11 / I)I0]; using the estimated frequency f of the current in the current-carrying conductor and the dependence of the second coupling coefficient on the current frequency, the value H of the second coupling coefficient at the estimated frequency current is obtained 12 (f) / I; the voltage V output by the magnetic sensor 12 and the value H of the second coupling coefficient at the estimated frequency current 12 (f) / I, the current value of the current in the current-carrying conductor is obtained as I=V 12 / {S[H 12 (f) / I]}.

[0012] Further, the estimated frequency is recalculated as the predetermined frequency to obtain a new estimated frequency, and a current value of the current in the current-carrying conductor calculated based on the new estimated frequency.

[0013] Further, the magnetic sensor is a Hall sensor, and the Hall sensor and the induction coil are located on the same side of the current-carrying conductor.

[0014] Further, the magnetic sensor is a magnetoresistive sensor, and the magnetoresistive sensor and the induction coil are respectively located on adjacent sides of the current-carrying conductor.

[0015] Compared with the prior art, the present invention is additionally provided with an induction coil and a signal processing circuit. The induction coil is located around or on one side of the current-carrying conductor; the signal processing circuit is configured to perform frequency compensation on the voltage output by the magnetic sensor based on the voltage output by the induction coil to detect the measured current, thereby improving the detection accuracy of high-frequency currents.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts. Among them:

[0017] Figure 1 is a schematic structural diagram of a current sensor for frequency compensation of an application coil in an embodiment of the present invention;

[0018] Figure 2 For Figure 1 is a schematic cross-sectional view along the A-A cross-sectional line of;

[0019] Figure 3 In one embodiment, Figure 1 the coupling coefficient of the current I to the magnetic field H in the current-carrying conductor 101 in 12 is a curve graph showing the dependence relationship with the current frequency;

[0020] Figure 4 is a schematic structural diagram of a current sensor for frequency compensation of an application coil in another embodiment of the present invention;

[0021] Figure 5 For Figure 4 is a schematic cross-sectional view along the B-B cross-sectional line of.

DETAILED DESCRIPTION

[0022] To make the above - mentioned objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] As used herein, an "embodiment" or "an embodiment" refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in an embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it an individual or alternative embodiment that is mutually exclusive with other embodiments. Unless otherwise specified, the terms indicating electrical connection such as "connected", "coupled", and "joined" in this article all mean directly or indirectly electrically connected.

[0024] Please refer to Figure 1 shown, which is a schematic structural diagram of a current sensor using an application coil for frequency compensation in an embodiment of the present invention. Please refer to Figure 2 shown, which is a cross - sectional schematic diagram along the Figure 1 A - A sectional line of Figure 1 and Figure 2 It can be seen that Figure 1 the current sensor shown in

[0025] The current - carrying conductor 101 is used to provide a flowing channel for the current I to be measured, so that the current I to be measured can flow through the current - carrying conductor 101. In the Figure 1 specific embodiment shown, the current - carrying conductor 101 is a straight conductor.

[0026] The induction coil 102 is located around or on one side of the current - carrying conductor 101. The magnetic field (or magnetic induction intensity) generated by the current I in the current - carrying conductor 101 at the induction coil 102 is called the first magnetic field (or first magnetic induction intensity) H 11 , and the first magnetic field (or first magnetic induction intensity) H 11 does not depend on the frequency of the current I in the current - carrying conductor 101.

[0027] The magnetic sensor 103 is located around or on one side of the current - carrying conductor 101. The magnetic field (or magnetic induction intensity) generated by the current I in the current - carrying conductor 101 at the magnetic sensor 103 is called the second magnetic field (or second magnetic induction intensity) H 12 , and the second magnetic field (or second magnetic induction intensity) H 12 depends on the frequency of the current I in the current - carrying conductor 101.

[0028] The distance from the induction coil 102 to the current-carrying conductor 101 is farther than the distance from the magnetic sensor 103 to the current-carrying conductor 101, such that the magnetic field H generated by the current I in the current-carrying conductor 101 at the magnetic sensor 103 12 is stronger (i.e., the second magnetic field H 12 is greater than the first magnetic field H 11 ).

[0029] In Figure 1 and Figure 2 shown in the specific embodiment, the magnetic sensor 103 is a Hall sensor; the Hall sensor 103 and the induction coil 102 are located on the same side of the current-carrying conductor 101, and the distance from the induction coil 102 to the current-carrying conductor 101 is farther than the distance from the Hall sensor 103 to the current-carrying conductor 101. It can also be said that the induction coil 102, the Hall sensor 103, and the current-carrying conductor 101 are arranged in parallel and spaced in sequence.

[0030] The induction coil 102 outputs a voltage V 11 based on the first magnetic field H 11 . The voltage V output by the induction coil 102 11 = 2πfμ0A(H 11 / I)I, where μ0 is the magnetic permeability of vacuum, A is the area enclosed by the induction coil 102, f is the frequency of the current in the current-carrying conductor 101, I is the current value of the current in the current-carrying conductor 101, and H 11 / I is the coupling coefficient of the current I in the current-carrying conductor 101 to the first magnetic field H 11 (or at the first magnetic field H 11 ), and among them, the coupling coefficient H 11 / I is called the first coupling coefficient.

[0031] The magnetic sensor 103 outputs a voltage V 12 based on the second magnetic field H 12 , and the voltage V output by the magnetic sensor 103 12 = S[H 12 (f) / I]I, where S is the sensitivity of the magnetic sensor 103 with respect to the magnetic field, I is the current value of the current in the current-carrying conductor 101, and H 12 (f) / I is the coupling coefficient of the current I in the current-carrying conductor 101 to the second magnetic field H 12 (or at the second magnetic field H 12 ), and among them, the coupling coefficient H 12 (f) / I is called the second coupling coefficient. Please refer to Figure 3 shown, which is in one embodiment Figure 1 of the current I in the current-carrying conductor 101 to the second magnetic field H12 The coupling coefficient (i.e., the second coupling coefficient) H 12 (f) / I versus the current frequency dependence curve graph.

[0032] The signal processing circuit is configured to detect the measured current I by performing frequency compensation on the voltage V output by the magnetic sensor 103 based on the voltage V output by the induction coil 102. The process of the signal processing circuit applying the induction coil 102 for frequency compensation is as follows. 11 and the voltage V output by the magnetic sensor 103 12 for frequency compensation. The signal processing circuit applies the induction coil 102 for frequency compensation as follows.

[0033] Based on the voltage V output by the magnetic sensor 103 12 and the value of the second coupling coefficient at a predetermined frequency (f0) current H 12 (f0) / I, an initial trial current I0 = V 12 / {S[H 12 (f0) / I]} is obtained, where f0 is the predetermined frequency of the predetermined frequency current. In one embodiment, the predetermined frequency (f0) current is a low-frequency current, and H 12 (f0) / I can be obtained by simulation or testing.

[0034] Using the voltage V output by the induction coil 102 11 and the initial trial current I0, an estimated frequency f of the current in the current-carrying conductor 101 is obtained as f = V 11 / [2πμ0A(H 11 / I)I0].

[0035] Using the estimated frequency f of the current in the current-carrying conductor 101 and the dependence of the second coupling coefficient on the current frequency (e.g., Figure 3 the shown dependence), the value of the second coupling coefficient at the estimated frequency current in the current-carrying conductor 101 H 12 (f) / I is obtained.

[0036] Based on the voltage V output by the magnetic sensor 103 12 and the value of the second coupling coefficient at the estimated frequency current in the current-carrying conductor 101 H 12 (f) / I, the current value I of the current in the current-carrying conductor 101 is obtained as I = V 12 / {S[H 12 (f) / I]}.

[0037] It should be noted that the signal processing circuit can also perform multiple iterations on the above process. For example, using the estimated frequency f as the predetermined frequency f0 for recalculation to obtain a new estimated frequency, and calculating a new current value of the current in the current-carrying conductor 101 based on the new estimated frequency. Thus, the current value of the current in the current-carrying conductor 101 finally obtained by the signal processing circuit is closer to the true value of the current in the current-carrying conductor 101.

[0038] In summary, Figure 1 The current sensor shown uses the induction coil 102 for frequency compensation, thereby improving the detection accuracy of high-frequency currents.

[0039] Please refer to Figure 4 shown, which is a schematic structural diagram of a current sensor using an application coil for frequency compensation in another embodiment of the present invention. Please refer to Figure 5 shown, which is along Figure 4 the B-B sectional line sectional schematic diagram. From Figure 4 and Figure 5 it can be seen that Figure 4 the current sensor shown includes a current-carrying conductor 201, an induction coil 202, a magnetic sensor 203, and a signal processing circuit (not shown). Figure 4 and Figure 1 The basic structures of the shown embodiments are the same, and the main difference is that Figure 1 the magnetic sensor 103 in Figure 4 is a Hall sensor; the magnetic sensor 203 in

[0040] The current-carrying conductor 201 is used to provide a flow-through channel for the current I to be measured, so that the current I to be measured can flow through the current-carrying conductor 201. In Figure 4 the specific embodiment shown, the current-carrying conductor 201 is a straight conductor.

[0041] The induction coil 202 is located around or on one side of the current-carrying conductor 201, and the magnetic field (or magnetic induction intensity) generated by the current I in the current-carrying conductor 201 at the induction coil 202 is called the first magnetic field (or first magnetic induction intensity) H 21 , and the first magnetic field (or first magnetic induction intensity) H 21 does not depend on the frequency of the current I in the current-carrying conductor 201.

[0042] The magnetic sensor 203 is located around or on one side of the current-carrying conductor 201, and the magnetic field (or magnetic induction intensity) generated by the current I in the current-carrying conductor 201 at the magnetic sensor 203 is called the second magnetic field (or second magnetic induction intensity) H 22 , and the second magnetic field (or second magnetic induction intensity) H 22depends on the frequency of the current I in the current-carrying conductor 201.

[0043] The distance from the induction coil 202 to the current-carrying conductor 201 is farther than the distance from the magnetic sensor 203 to the current-carrying conductor 201, such that the magnetic field H generated by the current I in the current-carrying conductor 201 at the magnetic sensor 203 22 is stronger (i.e., the second magnetic field H 22 is greater than the first magnetic field H 21 ).

[0044] At Figure 4 and Figure 5 shown in the specific embodiment, the magnetic sensor 203 is a magnetoresistive sensor; the magnetoresistive sensor 203 and the induction coil 202 are located on adjacent sides of the current-carrying conductor 201. For example, the magnetoresistive sensor 203 is located above (on the upper side) the current-carrying conductor 201; the induction coil 202 is located on the left side of the current-carrying conductor 201, and the magnetoresistive sensor 203 and the induction coil 202 are arranged in parallel and spaced apart.

[0045] The induction coil 202 outputs a voltage V 21 based on the first magnetic field H 21 . The voltage V output by the induction coil 202 21 = 2πfμ0A(H 21 / I)I, where μ0 is the magnetic permeability of vacuum, A is the area surrounded by the induction coil 202, f is the frequency of the current in the current-carrying conductor 201, I is the current value of the current in the current-carrying conductor 201, and H 21 / I is the coupling coefficient from the current I in the current-carrying conductor 201 to the first magnetic field H 21 (or at the first magnetic field H 21 ), where the coupling coefficient H 21 / I is called the first coupling coefficient.

[0046] The magnetic sensor 203 outputs a voltage V 22 based on the second magnetic field H 22 , and the voltage V output by the magnetic sensor 203 22 = S[H 22 (f) / I]I, where S is the sensitivity of the magnetic sensor 203 with respect to the magnetic field, I is the current value of the current in the current-carrying conductor 101, and H 22 (f) / I is the coupling coefficient from the current I in the current-carrying conductor 201 to the second magnetic field H 22 (or at the second magnetic field H 22 ), where the coupling coefficient H 22 (f) / I is called the second coupling coefficient.

[0047] The signal processing circuit is configured to perform frequency compensation on the voltage V output by the induction coil 202 21 for the voltage V output by the magnetic sensor 203 22 so as to detect the measured current I. The process of using the induction coil 202 by the signal processing circuit for frequency compensation is as follows.

[0048] Based on the voltage V output by the magnetic sensor 203 22 and the value H of the second coupling coefficient at a predetermined frequency (f0) current 22 (f0) / I, an initial trial current I0 = V 22 / {S[H 22 (f0) / I]} is obtained, where f0 is the predetermined frequency of the predetermined frequency current. In one embodiment, the predetermined frequency (f0) current is a low-frequency current, and H 22 (f0) / I can be obtained by simulation or testing.

[0049] Using the voltage V output by the induction coil 202 21 and the initial trial current I0, an estimated frequency f of the current in the current-carrying conductor 201 is obtained: f = V 21 / [2πμ0A(H 21 / I)I0].

[0050] Using the estimated frequency f of the current in the current-carrying conductor 201 and the curve of the dependence of the second coupling coefficient on the current frequency, the value H 22 (f) / I of the second coupling coefficient at the true current in the current-carrying conductor 201 is obtained;

[0051] Based on the voltage V output by the magnetic sensor 203 22 and the value H 22 (f) / I of the second coupling coefficient at the estimated frequency current in the current-carrying conductor 201, the current value I of the current in the current-carrying conductor 201 is obtained: I = V 22 / {S[H 22 (f) / I]}.

[0052] It should be noted that the signal processing circuit may also perform multiple iterations on the above process. For example, using the estimated frequency f as the predetermined frequency f0 for recalculation to obtain a new estimated frequency, and calculating a new current value of the current in the current-carrying conductor 201 based on the new estimated frequency, so that the current value of the current in the current-carrying conductor 201 finally obtained by the signal processing circuit is closer to the true value of the current in the current-carrying conductor 201.

[0053] In summary,Figure 4 The current sensor shown applies an induction coil 202 for frequency compensation, thereby improving the detection accuracy of high-frequency currents.

[0054] In the present invention, terms indicating electrical connection such as "connected", "linked", "joined", "connected to", etc., unless otherwise specified, mean direct or indirect electrical connection.

[0055] The above are only the preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those of ordinary skill in the art according to the disclosure of the present invention shall fall within the protection scope recorded in the claims.

Claims

1. A current sensor, characterized in that, It includes a current-carrying conductor, an induction coil, a magnetic sensor, and a signal processing circuit. The current-carrying conductor is used to provide a flow path for the current to be measured. The induction coil is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the induction coil is called the first magnetic field. The magnetic sensor is located around or on one side of the current-carrying conductor, and the magnetic field generated by the current in the current-carrying conductor at the magnetic sensor is called the second magnetic field. The signal processing circuit is used to perform frequency compensation on the voltage output by the magnetic sensor based on the voltage output by the induction coil to detect the current to be measured. The coupling coefficient of the current in the current-carrying conductor to the first magnetic field is called the first coupling coefficient; the coupling coefficient of the current in the current-carrying conductor to the second magnetic field is called the second coupling coefficient. The signal processing circuit performs the following operations: Obtain an initial trial current through the voltage output by the magnetic sensor and the value of the second coupling coefficient at a predetermined frequency current. Use the voltage output by the induction coil and the initial trial current to obtain the estimated frequency of the current in the current-carrying conductor. Use the estimated frequency of the current in the current-carrying conductor and the dependence of the second coupling coefficient on the current frequency to obtain the value of the second coupling coefficient at the estimated frequency current. Obtain the current value of the current in the current-carrying conductor through the voltage output by the magnetic sensor and the value of the second coupling coefficient at the estimated frequency current.

2. The current sensor according to claim 1, wherein: The first magnetic field is independent of the frequency of the current in the current-carrying conductor. The second magnetic field depends on the frequency of the current in the current-carrying conductor.

3. The current sensor according to claim 1, wherein: The distance from the induction coil to the current-carrying conductor is farther than the distance from the magnetic sensor to the current-carrying conductor. The second magnetic field is greater than the first magnetic field.

4. The current sensor according to claim 1, wherein: The voltage V output by the induction coil 11 = 2πfμ0A(H 11 / I)I, where μ0 is the magnetic permeability of vacuum, A is the area enclosed by the induction coil, H 11 / I is the first coupling coefficient, f is the frequency of the current in the current-carrying conductor, and I is the current value of the current in the current-carrying conductor; The voltage V output by the magnetic sensor 12 = S[H 12 (f) / I]I, where S is the sensitivity of the magnetic sensor relative to the magnetic field, H 12 (f) / I is the second coupling coefficient, and I is the current value of the current in the current-carrying conductor.

5. The current sensor according to claim 4, wherein: The voltage V output by the magnetic sensor 12 and the value H of the second coupling coefficient at the predetermined frequency current 12 (f0) / I, to obtain an initial trial current I0 = V 12 / {S[H 12 (f0) / I]}, where f0 is the predetermined frequency of the predetermined frequency current; Using the voltage V output by the induction coil 11 and the initial probing current I0, the estimated frequency f of the current in the current-carrying conductor is obtained as f = V 11 / [2πμ0A(H 11 / I)I0]; Using the estimated frequency f of the current in the current-carrying conductor and the dependence of the second coupling coefficient on the current frequency, the value H of the second coupling coefficient at the current of the estimated frequency is obtained 12 (f) / I; The voltage V output by the magnetic sensor 12 and the value H of the second coupling coefficient at the estimated frequency current 12 (f) / I, to obtain the current value I of the current in the current-carrying conductor I = V 12 / {S[H 12 (f) / I]}.

6. The current sensor according to claim 5, wherein: Recalculate the estimated frequency as the predetermined frequency to obtain a new estimated frequency and the current value of the current in the current-carrying conductor calculated based on the new estimated frequency.

7. The current sensor according to any one of claims 1-6, wherein: The magnetic sensor is a Hall sensor, and the Hall sensor and the induction coil are located on the same side of the current-carrying conductor.

8. The current sensor according to any one of claims 1-6, wherein: The magnetic sensor is a magnetoresistive sensor, and the magnetoresistive sensor and the induction coil are respectively located on adjacent sides of the current-carrying conductor.

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