Combined magnetic core type broadband current sensor

Abstract

Disclosed is a combined magnetic core-type broadband current sensor. The combined magnetic core-type broadband current sensor includes a high-frequency unit surrounding a measured current for sensing the high-frequency component of the measured current, a low-frequency unit for sensing the low-frequency component of the measured current, and a transition unit that transitionally connects the high-frequency unit and the low-frequency unit. Under the excitation of the measured current, the high-frequency magnetic core generates a high-frequency magnetic field that is linearly related to the high-frequency component of the measured current. A high-frequency winding is wound on the surface of the high-frequency magnetic core to induce a high-frequency voltage signal that is linearly related to the high-frequency magnetic field. Under the excitation of the measured current, the low-frequency magnetic core generates a low-frequency magnetic field that is linearly related to the low-frequency component of the measured current. A low-frequency winding is wound on the surface of the low-frequency magnetic core to induce a low-frequency voltage signal that is linearly related to the low-frequency magnetic field. By combining the high-frequency and low-frequency magnetic cores, combined measurement of the high-frequency and low-frequency units is achieved, thereby realizing broadband measurement of pulsed current.

Description

Technical Field

[0001] The present invention belongs to the technical field of current sensors, in particular to a combined magnetic core type broadband current sensor. Background Art

[0002] Rapidly changing current pulses have important applications in many major scientific and technological fields, such as the pulse current used in power semiconductor testing of core electronic devices, the signal current excited by high-power laser power source energy modules, and the rapidly changing pulse current induced by equipment in strong pulse radiation environments. Accurately measuring these pulse current signals is the basis for developing high-performance pulse power equipment and exploring the effects of strong pulse radiation. It is of great significance for basic physics research and the development of new technologies. The rising edge of the above-mentioned pulse current signal can be as fast as nanoseconds, which requires the current sensor used to have an ultra-wide frequency response characteristic, and the operating frequency band needs to be distributed from several thousand hertz to several hundred megahertz.

[0003] Measuring rapidly changing pulse current signals is usually based on Ampere's law and Faraday's law of electromagnetic induction. A multi-turn coil is wound and the mutual induction between it and the current-carrying conductor of the measured current is used to measure the measured current. In order to improve the mutual induction effect between the wound coil and the measured current, the coil needs to be wound on a magnetic core made of magnetic material. However, the magnetic permeability of the magnetic core is related to the frequency of the excitation magnetic field. Due to the characteristics of the magnetic material itself, current magnetic core materials are divided into two categories: one has good magnetic field response characteristics in the low frequency band, and the other has good magnetic field response characteristics in the high frequency band. There is no magnetic material that has the same magnetic permeability coefficient in the range of several thousand hertz to several hundred megahertz. The insufficient frequency response of the magnetic core's magnetic permeability coefficient also greatly limits the frequency response characteristics of the current sensor, which in turn makes it impossible to accurately measure fast pulse current signals that change in the nanosecond level.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] In response to the problems existing in the prior art, the present invention proposes a combined magnetic core type broadband current sensor to achieve accurate and effective measurement of current signals with rapid changes in time domain and ultra-wide frequency band.

[0006] The object of the present invention is achieved through the following technical solution: a combined magnetic core type broadband current sensor includes a high-frequency unit surrounding the measured current for sensing the high-frequency component of the measured current, a low-frequency unit for sensing the low-frequency component of the measured current, and a transition unit for transitionally connecting the high-frequency unit and the low-frequency unit, wherein:

[0007] The high frequency unit includes:

[0008] A high-frequency magnetic core, which generates a high-frequency magnetic field linearly related to the high-frequency component of the measured current under the excitation of the measured current;

[0009] A high-frequency winding wound on the surface of the high-frequency magnetic core to induce a high-frequency voltage signal linearly related to the high-frequency magnetic field;

[0010] The low frequency unit includes:

[0011] A low-frequency magnetic core, which generates a low-frequency magnetic field linearly related to the low-frequency component of the measured current under the excitation of the measured current;

[0012] A low-frequency winding, wound around the surface of the low-frequency magnetic core to induce a low-frequency voltage signal linearly related to the low-frequency magnetic field;

[0013] The transition unit includes,

[0014] an upper low-frequency transition magnetic core connected to the upper end of the high-frequency magnetic core;

[0015] a lower low-frequency transition magnetic core connected to the lower end of the high-frequency magnetic core;

[0016] an upper high-frequency transition magnetic core connected to the upper end of the low-frequency magnetic core;

[0017] The lower high-frequency transition magnetic core is connected to the lower end of the low-frequency magnetic core.

[0018] In the combined magnetic core type broadband current sensor, the upper low-frequency transition magnetic core is connected to the upper high-frequency transition magnetic core at the upper magnetic core interface, and the lower low-frequency transition magnetic core is connected to the lower high-frequency transition magnetic core at the lower magnetic core interface.

[0019] In the combined magnetic core type broadband current sensor, the transition magnetic core has a gradient-varying magnetic permeability coefficient, the magnetic permeability coefficients at the connection between the high-frequency magnetic core and the upper low-frequency transition magnetic core and the lower low-frequency transition magnetic core are the same, the magnetic permeability coefficients at the connection between the low-frequency magnetic core and the upper high-frequency transition magnetic core and the lower high-frequency transition magnetic core are the same, the magnetic permeability coefficients at the upper magnetic core interface between the upper low-frequency transition magnetic core and the upper high-frequency transition magnetic core are the same, and the magnetic permeability coefficients at the lower low-frequency transition magnetic core and the lower high-frequency transition magnetic core are the same at the lower magnetic core interface.

[0020] In the combined magnetic core type broadband current sensor, the high-frequency magnetic core, the low-frequency magnetic core and the transition magnetic core are in contact with each other through the upper magnetic core interface and the lower magnetic core interface to form a ring-shaped magnetic core.

[0021] In the combined magnetic core type broadband current sensor, the annular magnetic core is placed inside a detachable annular coil housing.

[0022] In the combined magnetic core type broadband current sensor, the lower ends of the high-frequency winding and the low-frequency winding are electrically connected by a connecting wire passing through the lower magnetic core interface, the upper end of the high-frequency winding is connected to the ground end of the broadband connector through the coil housing, and the upper end of the low-frequency winding is electrically connected to the core of the broadband connector after passing through the integral resistance unit.

[0023] In the combined magnetic core type broadband current sensor, the integrating resistor unit is a PCB circuit board on which non-inductive chip resistors are arranged in parallel.

[0024] In the combined magnetic core type wide-band current sensor, the lower cutoff frequency of the high-frequency magnetic core is equal to the upper cutoff frequency of the low-frequency magnetic core.

[0025] In the combined magnetic core type broadband current sensor, the frequency response range of the high-frequency magnetic core is 50MHz to 300MHz, and its lower limit cutoff frequency is 50MHz; the frequency response range of the low-frequency magnetic core is 10kHz to 50MHz, and its upper limit cutoff frequency is 50MHz.

[0026] In the combined magnetic core type broadband current sensor, the upper low-frequency transition magnetic core and the lower low-frequency transition magnetic core are magnetically cast and connected to the upper port and lower port of the high-frequency magnetic core respectively, and the upper high-frequency transition magnetic core and the lower high-frequency transition magnetic core are magnetically cast and connected to the upper port and lower port of the low-frequency magnetic core respectively.

[0027] Compared with the existing technology, the present invention has the following advantages: the combined magnetic core type wide-band current sensor described in the present invention addresses the shortcomings of the magnetic frequency response of a single magnetic material. By effectively combining high-frequency and low-frequency magnetic cores, it can achieve fast current pulse signal measurement with an ultra-wide frequency distribution. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Various other advantages and benefits of the present invention will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are intended only to illustrate preferred embodiments and are not to be construed as limiting the present invention. It should be understood that the drawings described below are merely examples of the present invention, and that those skilled in the art will be able to derive other drawings from these drawings without inventive effort. Throughout the drawings, identical reference numerals are used to denote identical components.

[0029] In the attached figure:

[0030] Figure 1 4 is a schematic structural diagram of a combined magnetic core type broadband current sensor according to an embodiment of the present invention.

[0031] The present invention will be further explained below with reference to the accompanying drawings and embodiments. DETAILED DESCRIPTION

[0032] Specific embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although specific embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0033] It should be noted that certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that technicians may use different nouns to refer to the same component. This specification and claims do not use the difference in nouns as a way to distinguish components, but use the difference in the functions of the components as the criterion for distinction. As mentioned throughout the specification and claims, "including" or "comprising" is an open term, so it should be interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the invention. The scope of protection of the present invention shall be as defined in the attached claims.

[0034] To facilitate understanding of the embodiments of the present invention, further explanation will be given below using specific embodiments as examples in conjunction with the accompanying drawings, and the accompanying drawings do not constitute a limitation on the embodiments of the present invention.

[0035] For better understanding, Figure 1 As shown, the combined magnetic core type broadband current sensor includes a high-frequency unit surrounding the measured current for sensing the high-frequency component of the measured current, a low-frequency unit for sensing the low-frequency component of the measured current, and a transition unit for transitionally connecting the high-frequency unit and the low-frequency unit, wherein,

[0036] The high frequency unit includes:

[0037] A high-frequency magnetic core 1, which generates a high-frequency magnetic field linearly related to the high-frequency component of the measured current under the excitation of the measured current;

[0038] A high-frequency winding 10, which is wound on the surface of the high-frequency magnetic core 1 to induce a high-frequency voltage signal that is linearly related to the high-frequency magnetic field;

[0039] The low frequency unit includes:

[0040] A low-frequency magnetic core 2, which generates a low-frequency magnetic field linearly related to the low-frequency component of the measured current under the excitation of the measured current;

[0041] A low-frequency winding 11, which is wound around the surface of the low-frequency magnetic core 2 to induce a low-frequency voltage signal that is linearly related to the low-frequency magnetic field;

[0042] The transition unit includes,

[0043] an upper low-frequency transition magnetic core 4 connected to the upper end of the high-frequency magnetic core 1;

[0044] a lower low-frequency transition magnetic core 7 connected to the lower end of the high-frequency magnetic core 1;

[0045] an upper high-frequency transition magnetic core 5 connected to the upper end of the low-frequency magnetic core 2;

[0046] The lower high-frequency transition magnetic core 8 is connected to the lower end of the low-frequency magnetic core 2 .

[0047] In a preferred embodiment of the combined magnetic core type broadband current sensor, the upper low-frequency transition magnetic core 4 is connected to the upper high-frequency transition magnetic core 5 at the upper magnetic core interface 6, and the lower low-frequency transition magnetic core 7 is connected to the lower high-frequency transition magnetic core 8 at the lower magnetic core interface 9.

[0048] In a preferred embodiment of the combined magnetic core type broadband current sensor, the transition magnetic core has a gradient-varying magnetic permeability coefficient, the magnetic permeability coefficients at the connection between the high-frequency magnetic core 1 and the upper low-frequency transition magnetic core 4 and the lower low-frequency transition magnetic core 7 are the same, the magnetic permeability coefficients at the connection between the low-frequency magnetic core 2 and the upper high-frequency transition magnetic core 5 and the lower high-frequency transition magnetic core 8 are the same, the magnetic permeability coefficients at the upper magnetic core interface 6 between the upper low-frequency transition magnetic core 4 and the upper high-frequency transition magnetic core 5 are the same, and the magnetic permeability coefficients at the lower low-frequency transition magnetic core 7 and the lower high-frequency transition magnetic core 8 are the same at the lower magnetic core interface 9.

[0049] In a preferred embodiment of the combined magnetic core type broadband current sensor, the high-frequency magnetic core 1 , the low-frequency magnetic core 2 and the transition magnetic core are in contact with each other through the upper magnetic core interface 6 and the lower magnetic core interface 9 to form a ring-shaped magnetic core.

[0050] In a preferred embodiment of the combined magnetic core type broadband current sensor, the annular magnetic core is placed inside a detachable annular coil housing.

[0051] In a preferred embodiment of the combined magnetic core type broadband current sensor, the lower ends of the high-frequency winding 10 and the low-frequency winding 11 are electrically connected via a connecting wire passing through the lower magnetic core interface 9, the upper end of the high-frequency winding 10 is connected to the ground end of the broadband connector 13 through the coil housing, and the upper end of the low-frequency winding 11 is electrically connected to the core of the broadband connector 13 after passing through the integral resistor unit 12.

[0052] In a preferred embodiment of the combined magnetic core type broadband current sensor, the integrating resistor unit 12 is a PCB circuit board on which non-inductive chip resistors are arranged in parallel.

[0053] In a preferred embodiment of the combined magnetic core type wideband current sensor, the lower cutoff frequency of the high-frequency magnetic core 1 is equal to the upper cutoff frequency of the low-frequency magnetic core 2 .

[0054] In a preferred embodiment of the combined magnetic core type broadband current sensor, the frequency response range of the high-frequency magnetic core 1 is 50MHz to 300MHz, and its lower cutoff frequency is 50MHz; the frequency response range of the low-frequency magnetic core 2 is 10kHz to 50MHz, and its upper cutoff frequency is 50MHz.

[0055] In a preferred embodiment of the combined magnetic core type broadband current sensor, the upper low-frequency transition magnetic core 4 and the lower low-frequency transition magnetic core 7 are magnetically cast connected to the upper port and the lower port of the high-frequency magnetic core 1, respectively, and the upper high-frequency transition magnetic core 5 and the lower high-frequency transition magnetic core 8 are magnetically cast connected to the upper port and the lower port of the low-frequency magnetic core 2, respectively.

[0056] In one embodiment, Figure 1 As shown, a combined magnetic core type broadband current sensor includes a high-frequency unit, a low-frequency unit and a transition unit. The high-frequency unit can effectively sense the high-frequency component of the measured current, the low-frequency unit can effectively sense the low-frequency component of the measured current, and the transition unit realizes the transition connection between the high-frequency unit and the low-frequency unit. Through the combined measurement of the high-frequency and low-frequency units, broadband measurement of the pulse current is realized.

[0057] In a preferred embodiment of the combined magnetic core type broadband current sensor, the high-frequency unit includes a high-frequency winding 10 and a high-frequency magnetic core 1. The high-frequency magnetic core 1 has a flat magnetic permeability response curve in the high-frequency range. The high-frequency magnetic core 1 can be made of high-frequency magnetic ceramic materials such as manganese zinc and nickel zinc ferrite. Under the excitation of the measured current, the high-frequency magnetic core 1 can generate a high-frequency magnetic field linearly related to the high-frequency component of the measured current. The high-frequency winding 10 is wound on the surface of the high-frequency magnetic core 1, and induces a high-frequency voltage signal linearly related to the high-frequency magnetic field inside the high-frequency magnetic core 1.

[0058] In a preferred embodiment of the combined magnetic core-type broadband current sensor, the low-frequency unit includes a low-frequency winding 11 and a low-frequency magnetic core 2. The low-frequency magnetic core 2 has a flat magnetic permeability response curve within the low-frequency range. The low-frequency magnetic core 2 can be made of a low-frequency magnetic material such as Permalloy or an amorphous alloy. Under the excitation of the measured current, the low-frequency magnetic core 2 can generate a low-frequency magnetic field therein that is linearly related to the low-frequency component of the measured current. The low-frequency winding 11 is wound around the surface of the low-frequency magnetic core 2, and induces a low-frequency voltage signal that is linearly related to the low-frequency magnetic field inside the low-frequency magnetic core 2.

[0059] In a preferred embodiment of the combined magnetic core type broadband current sensor, the transition unit includes an upper low-frequency transition magnetic core 4, an upper high-frequency transition magnetic core 5, a lower low-frequency transition magnetic core 7 and a lower high-frequency transition magnetic core 8. The upper low-frequency transition magnetic core 4 and the lower low-frequency transition magnetic core 7 are magnetically cast and connected to the upper port and the lower port of the high-frequency magnetic core 1, respectively, to achieve the transition from the high-frequency magnetic core 1 to the low-frequency magnetic core 2. The upper high-frequency transition magnetic core 5 and the lower high-frequency transition magnetic core 8 are magnetically cast and connected to the upper port and the lower port of the low-frequency magnetic core 2, respectively, to achieve the transition from the low-frequency magnetic core 2 to the high-frequency magnetic core 1.

[0060] In one embodiment, the frequency response range of the high-frequency magnetic core 1 is 50MHz to 300MHz, and its lower cutoff frequency is 50MHz. The frequency response range of the low-frequency magnetic core 2 is 10kHz to 50MHz, and its upper cutoff frequency is 50MHz. The lower cutoff frequency of the high-frequency magnetic core 1 and the upper cutoff frequency of the low-frequency magnetic core 2 are equal. The combination of the high-frequency magnetic core 1 and the low-frequency magnetic core 2 can achieve a broadband magnetic field response of 10kHz to 300MHz.

[0061] In one embodiment, the high-frequency winding 10 and the low-frequency winding 11 have different numbers of winding turns according to the magnetic permeability coefficients of the high-frequency magnetic core 1 and the low-frequency magnetic core 2, thereby ensuring that the high-frequency unit and the low-frequency unit have the same response.

[0062] In a preferred embodiment of the combined magnetic core type broadband current sensor, the transition magnetic core has a gradient-varying magnetic permeability coefficient. The magnetic permeability coefficients at the connection between the high-frequency magnetic core 1 and the upper low-frequency transition magnetic core 4 and the lower low-frequency transition magnetic core 7 are the same, and the relative magnetic permeabilities are both 4000. The magnetic permeability coefficients at the connection between the low-frequency magnetic core 2 and the upper high-frequency transition magnetic core 5 and the lower high-frequency transition magnetic core 8 are the same, and the relative magnetic permeabilities are both 10000. The magnetic permeability coefficients at the upper magnetic core interface 6 of the upper low-frequency transition magnetic core 4 and the upper high-frequency transition magnetic core 5 are the same, and the magnetic permeability coefficients at the lower magnetic core interface 9 of the lower low-frequency transition magnetic core 7 and the lower high-frequency transition magnetic core 8 are the same, thereby reducing the distortion and attenuation of the magnetic field caused by the discontinuity of the magnetic permeability at the magnetic core interface.

[0063] In a preferred embodiment of the combined magnetic core type broadband current sensor, the high-frequency magnetic core 1, the low-frequency magnetic core 2 and the transition magnetic core are in contact with each other through the upper magnetic core interface 6 and the lower magnetic core interface 9 to form a ring-shaped magnetic core. The ring-shaped magnetic core is placed inside the detachable ring-shaped coil housing 3 to achieve shielding against external electric field interference.

[0064] In a preferred embodiment of the combined magnetic core type broadband current sensor, the lower ends of the high-frequency winding 10 and the low-frequency winding 11 are electrically connected by a connecting wire passing through the lower magnetic core interface 9, the upper end of the high-frequency winding 10 is connected to the ground end of the broadband connector 13 through the coil housing, and the upper end of the low-frequency winding 11 is electrically connected to the core of the broadband connector 13 after passing through the integral resistor unit 12, thereby realizing the series connection of the current signals detected by the high-frequency unit and the low-frequency unit.

[0065] In a preferred embodiment of the combined magnetic core type broadband current sensor, the integrating resistor unit 12 is a PCB circuit board on which non-inductive chip resistors are arranged in parallel, and a total of 8 400Ω non-inductive chip resistors are connected in parallel to form a 50Ω integrating resistor.

[0066] Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-mentioned specific embodiments and application fields. The above-mentioned specific embodiments are merely illustrative and instructive, and are not restrictive. A person skilled in the art, guided by this specification and without departing from the scope of protection of the claims of the present invention, may also devise various forms, all of which fall within the scope of protection of the present invention.

Claims

1. A combined magnetic core type broadband current sensor, characterized in that: It includes a high-frequency unit surrounding the measured current for inducing the high-frequency component of the measured current, a low-frequency unit for inducing the low-frequency component of the measured current, and a transition unit for transitionally connecting the high-frequency unit and the low-frequency unit, wherein: The high frequency unit includes: A high-frequency magnetic core, which generates a high-frequency magnetic field linearly related to the high-frequency component of the measured current under the excitation of the measured current; A high-frequency winding wound on the surface of the high-frequency magnetic core to induce a high-frequency voltage signal linearly related to the high-frequency magnetic field; The low frequency unit includes: A low-frequency magnetic core, which generates a low-frequency magnetic field linearly related to the low-frequency component of the measured current under the excitation of the measured current; A low-frequency winding, wound around the surface of the low-frequency magnetic core to induce a low-frequency voltage signal linearly related to the low-frequency magnetic field; The transition unit includes, an upper low-frequency transition magnetic core connected to the upper end of the high-frequency magnetic core; a lower low-frequency transition magnetic core connected to the lower end of the high-frequency magnetic core; an upper high-frequency transition magnetic core connected to the upper end of the low-frequency magnetic core; The lower high-frequency transition magnetic core is connected to the lower end of the low-frequency magnetic core. The upper low-frequency transition magnetic core is connected to the upper high-frequency transition magnetic core at the upper magnetic core interface. The lower low-frequency transition magnetic core is connected to the lower high-frequency transition magnetic core at the lower magnetic core interface. The transition magnetic core has a gradient-varying magnetic permeability coefficient. The magnetic permeability coefficients at the connection between the high-frequency magnetic core and the upper low-frequency transition magnetic core and the lower low-frequency transition magnetic core are the same. The magnetic permeability coefficients at the connection between the low-frequency magnetic core and the upper high-frequency transition magnetic core and the lower high-frequency transition magnetic core are the same. The magnetic permeability coefficients at the upper magnetic core interface between the upper low-frequency transition magnetic core and the upper high-frequency transition magnetic core are the same. The magnetic permeability coefficients at the lower magnetic core interface between the lower low-frequency transition magnetic core and the lower high-frequency transition magnetic core are the same.

2. The combined magnetic core type broadband current sensor according to claim 1, characterized in that: The high-frequency magnetic core, the low-frequency magnetic core and the transition magnetic core are in contact with each other through the upper magnetic core interface and the lower magnetic core interface to form a ring-shaped magnetic core.

3. The combined magnetic core type broadband current sensor according to claim 2, characterized in that: The annular magnetic core is placed inside a detachable annular coil housing.

4. The combined magnetic core type broadband current sensor according to claim 1, characterized in that: The lower ends of the high-frequency winding and the low-frequency winding are electrically connected through a connecting wire passing through the lower magnetic core interface, the upper end of the high-frequency winding is connected to the ground end of the broadband connector through the coil shell, and the upper end of the low-frequency winding is electrically connected to the core of the broadband connector after passing through the integral resistance unit.

5. The combined magnetic core type broadband current sensor according to claim 4, characterized in that: The integral resistance unit is a PCB circuit board on which non-inductive chip resistors are arranged in parallel.

6. The combined magnetic core type broadband current sensor according to claim 1, characterized in that: The lower cutoff frequency of the high-frequency magnetic core is equal to the upper cutoff frequency of the low-frequency magnetic core.

7. The combined magnetic core type broadband current sensor according to claim 1, characterized in that: The frequency response range of the high-frequency magnetic core is 50 MHz to 300 MHz, with a lower cutoff frequency of 50 MHz. The frequency response range of the low-frequency magnetic core is 10 kHz to 50 MHz, with an upper cutoff frequency of 50 MHz.

8. The combined magnetic core type broadband current sensor according to claim 1, characterized in that: The upper low-frequency transition core and the lower low-frequency transition core are magnetically cast connected to the upper port and the lower port of the high-frequency core respectively, and the upper high-frequency transition core and the lower high-frequency transition core are magnetically cast connected to the upper port and the lower port of the low-frequency core respectively.

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