Novel magnetism gathering ring considering optimized position bias error

Abstract

According to the novel magnetism gathering ring considering the optimized position offset error, the mode that magnetic sheets are arranged in a stagger mode is adopted, and the magnetic sheets are in a force arm shape and are directly formed after being stacked; the magnetic sheets are arranged in a staggered manner, so that sensor output errors caused by position offset can be effectively optimized, the output precision of the sensor is greatly improved, and hysteresis drift and unequal potential drift and geomagnetic drift of Hall elements caused by wire position offset are effectively slowed down; the magnetic gathering ring adopts a trapezoidal structural design of opening chain, and can effectively reduce the dynamic'zero balance 'instability of a central magnetic field at an air gap caused by offset of a Hall element placed at the central position of the air gap.

Description

Technical Field

[0001] The invention belongs to the field of current sensor design, and in particular relates to a novel magnetic concentrating ring that takes into account the optimization of position bias error. Background Art

[0002] The most representative non-contact current sensor is the Hall effect current sensor. The ability of the Hall effect sensor's magnetic field focusing ring to concentrate the magnetic field significantly affects the current sensor's measurement accuracy. The ring's structure, air gap width, number of air gaps, eccentricity of the measured conductor, and the offset of the Hall effect element in the air gap all affect the sensor's accuracy.

[0003] At present, a lot of research has been conducted at home and abroad based on improving the ability of magnetic field gathering rings to gather magnetic fields. Patent CN109633213A, named a magnetic field gathering ring for current sensors, is a group of four circular magnetic rings with air gaps made by micromachining technology. The advantage is that it effectively reduces the size and weight of the magnetic field gathering ring. The disadvantage is that the air gap has a poor magnetic field gathering effect and external signals can easily enter the magnetic ring, resulting in a decrease in the system signal-to-noise ratio and sensitivity performance. Patent CN 115831529B, named a magnetic field gathering ring and current sensor, is a rectangular ring with an air gap. Two magnetic gathering bodies are added at the air gap position to further gather signals to the sensing structure. The advantage is that the sensor accuracy is improved. The disadvantage is that the number of assemblies is large, the structure is complex, and the structural assembly error will affect the sensor output accuracy. Patent CN 114994385A, entitled "Current Sensor Tip Magnetic Ring," comprises two symmetrically arranged U-shaped or C-shaped magnetic rings, with the openings of the magnetic rings designed as pointed openings. This has the advantage of being able to achieve a magnetic amplification effect at the opposing openings, but the disadvantage is that the two air gaps have poor magnetic focusing effects. Patent CN 116754815 B, entitled "Current Sensor," addresses the issue of significant interference from the ambient magnetic field on the current sensor's detection through a shielding cover design. The magnetic ring of this current sensor is a common circular ring design, and similarly does not address the output error caused by eccentricity of the measured conductor and Hall element bias in the air gap. Patent CN202522605U, entitled "Magnetic Core for Current Sensor and Corresponding Current Sensor," features a circular ring design with polygonal through-holes formed into air gaps. The advantage is that the core edge is continuous, protecting the detector within the air gap from external electromagnetic interference. The disadvantage is that the size and positioning of the through-holes are difficult to control during the core molding process. Summary of the Invention

[0004] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a new type of magnetic focusing ring that takes into account the optimization of position bias error, so as to solve the technical problems in the prior art that the eccentricity of the position of the measured conductor, the air gap, and the bias of the Hall element assembly position will seriously affect the output accuracy of the sensor.

[0005] The present invention provides a new type of magnetic focusing ring that takes into account the optimization of position bias error. The magnetic sheets are staggered and placed. The magnetic sheets are in a "lever arm shape". The right side of the magnetic sheet is semicircular and connected to the rectangle. The rectangle at the lower end of the left side is at an oblique angle to the upper end. The surface is processed by magnetron sputtering technology.

[0006] The magnetic sheets are staggered on the left and right to form a magnetic focusing ring. The hollow position at the lower end is an air gap where the Hall element is placed. When current passes through the flow to be measured, a magnetic signal is generated based on the principle of electromagnetic induction. The magnetic focusing ring gathers and amplifies the magnetic signal, and the Hall element detects the current signal to be measured based on the magnetic signal. The semicircular and rounded corner design of the magnetic focusing ring can prevent local magnetic lines of force from concentrating. The tilt angle design at the upper end can allow the magnetic lines of force to converge and amplify the magnetic signal, which is evenly and stably distributed inside the magnetic sheet.

[0007] The magnetic sheets are assembled in a staggered arrangement, ensuring consistent product formation during processing. Direct molding after lamination eliminates the need for secondary processing, thus avoiding the internal stress that can occur during secondary processing. The stress release process can affect the core assembly position, thereby affecting the air gap width. This makes it difficult to maintain the air gap within the 1mm-1.5mm range, thus affecting sensor output accuracy.

[0008] The beneficial effects of the present invention are as follows:

[0009] 1. The staggered placement of magnetic sheets in the magnetic focusing ring of this invention can effectively reduce sensor output errors caused by position offsets, including wire position offset, air gap offset during assembly, and Hall element position offset in the air gap center, compared to magnetic focusing rings with integrated flat air gaps. This can significantly improve sensor output accuracy.

[0010] 2. Compared with improving the magnetic focusing performance by increasing the number of air gaps, the present invention has a better magnetic focusing effect with fewer air gaps, and external interference signals are not easy to enter the magnetic ring, and the signal-to-noise ratio and sensitivity are high;

[0011] 3. Compared with improving the magnetic focusing performance by adding a magnetic focusing body, the present invention has a simple assembly relationship, light weight, small volume and size, and is suitable for miniaturization scene requirements;

[0012] 4. The present invention adopts traditional processing methods, with low processing costs, no need for secondary processing, and no sensor drift error caused by internal stress generated by secondary processing. The product has good consistency and stability;

[0013] 5. The surface of the magnetic ring adopts magnetron sputtering thin film process technology, which effectively improves the microstructure of the surface of the magnetic ring, and improves the magnetic resistance value, magnetic properties and corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which constitute a part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an improper limitation of the present invention.

[0015] Figure 1 This is a structural diagram of a "lever-arm type" magnetic sheet according to an embodiment of the present invention;

[0016] Figure 2 1 is a diagram of a layered "trapezoidal" magnetic focusing ring structure according to an embodiment of the present invention.

[0017] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0018] This embodiment provides a new type of magnetic focusing ring that takes into account the optimization of position bias error, and adopts staggered assembly and placement of magnetic sheets. The magnetic sheet structure is as follows: Figure 1 As shown, it is a "lever arm shape." The right side of the magnetic disc is a semicircle with a diameter of 4.5 mm, connected to the rectangle. The distance from the left edge of the upper end of the magnetic disc to the center of the right circle is 28.25 mm, and the distance from the upper boundary of the left side to the lower boundary is 24.5 mm. The rectangle at the lower left end is 3 mm wide and 4.6 mm long, forming an oblique angle of approximately 22 degrees with the upper end. The lower end is a rectangle with a diameter of 3 x 14.7 mm and a thickness of 0.4 mm.

[0019] Furthermore, the magnetic sheet material may be selected from amorphous alloy, Permalloy or silicon steel, and the surface may be processed by magnetron sputtering technology.

[0020] The magnetic sheets are staggered in a left-right arrangement to form a magnetic focusing ring. The hollow area at the bottom serves as an air gap, where a Hall element is placed. When current flows through the measured flow, a magnetic signal is generated based on the principle of electromagnetic induction. The magnetic focusing ring converges and amplifies the magnetic signal, and the Hall element detects the measured current signal based on the magnetic signal. The semicircular and rounded corners of the magnetic focusing ring prevent local concentration of magnetic lines of force. The tilted angle design at the top allows the magnetic lines of force to converge and amplify the magnetic signal, evenly and smoothly distributing it within the magnetic sheet. The magnetic sheets are staggered in a left-right arrangement, and during the processing of the magnetic sheets, the product molding consistency is good. Direct molding after lamination eliminates the need for secondary processing, avoiding the problem of internal stress generated by secondary processing. The internal stress release process affects the assembly position of the magnetic core, thereby affecting the output accuracy of the sensor.

[0021] Furthermore, the outer dimensions of the magnetic ring are 33x24.5mm, and the air gap distance is 4mm. Figure 2As shown, it is a layered "trapezoidal" magnetic ring structure.

[0022] Furthermore, there are six magnetic sheets, which are placed in a staggered manner with three sheets on the left and three sheets on the right to form a magnetic ring. Compared with the magnetic ring with an integrated planar air gap, it can effectively reduce the hysteresis drift caused by the position offset of the wire and the unequal potential drift of the Hall element and the geomagnetic drift, which lead to the output error of the current sensor.

[0023] Furthermore, the magnetic focusing ring adopts an open-layer "trapezoidal" structure design, which can effectively reduce the offset of the Hall element placed in the center of the air gap, causing the dynamic "zero balance" of the magnetic field in the center of the air gap to be unstable, thereby causing temperature drift errors when the temperature of the current sensor changes.

[0024] Furthermore, the staggered magnetic ring structure design simplifies the assembly process and can effectively reduce the sensor output error caused by the air gap position deviation during the assembly process.

[0025] Furthermore, the "lever arm type" 22° tilt angle design of the magnetic sheet effectively gathers and amplifies the magnetic signal, and the magnetic lines are evenly and smoothly distributed inside the magnetic sheet, with no magnetic concentration points.

[0026] The output changes of the current sensor are compared when the conductor under test is located at the center of the magnetic ring and when the conductor is offset from the center to the edge of the ring (the worst case). Within the measuring range, conductor eccentricity has little effect on the measurement results, with the relative error being controlled within 0.2%. Compared to the relative error of a typical Hall effect current sensor, the relative error is around 1%. The magnetic ring with staggered air gaps can effectively reduce the error caused by conductor position deviation compared to a flat air gap.

[0027] The magnetic induction intensity in a planar air gap surface changes significantly with the air gap, decreasing significantly as the air gap distance increases before eventually leveling off. In comparison, the staggered interface structure of the present invention exhibits a slight decrease in magnetic induction intensity as the air gap increases. However, when the air gap distance is 0.5 mm, the magnetic induction intensity can still reach 90.5% of the value at zero air gap distance, while the magnetic induction intensity in a planar air gap surface with the same air gap distance is only 16.62% of the value at zero air gap distance. Therefore, the staggered interface magnetic core structure can, to a certain extent, reduce the sensor output error caused by air gap position deviation during the actual assembly and application of the current sensor.

[0028] The Hall element should be placed at the center of the air gap, but in actual applications, positional deviation is inevitable. The magnetic induction intensity of the Hall element at the edge of the air gap can reach 99.89% of the magnetic induction intensity of the Hall element at the center of the air gap, verifying that the current sensor with this structure has strong anti-interference performance.

[0029] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A new type of magnetic focusing ring that takes into account the optimization of position bias error, characterized in that: The same magnetic sheets are staggered and assembled on the left and right sides. The magnetic sheets are integrally formed, with the upper right end being semicircular and connected to the rectangle, and the lower end being "L-shaped", with the "L-shaped" structure forming an oblique angle with the upper end; The hollow position at the lower end of the magnetic focusing ring is an air gap, which is used to place a Hall element, so as to detect the current signal to be measured based on the magnetic signal.

2. A novel magnetic focusing ring considering optimization of position bias error according to claim 1, characterized in that: The bevel angle is 22°, which can effectively amplify the magnetic signal, and the magnetic lines are evenly and smoothly distributed inside the magnetic sheet without any magnetic concentration point.

3. The novel magnetic focusing ring according to claim 1, wherein: The surface of the magnetic sheet is processed by magnetron sputtering thin film technology.

4. The novel magnetic focusing ring according to claim 1, wherein: The magnetic focusing ring adopts six magnetic pieces, three on the left and three on the right, which are placed in a staggered manner.

5. The novel magnetic focusing ring according to claim 1, wherein: The magnetic focusing ring adopts a trapezoidal structure design with open layers.

6. The novel magnetic focusing ring according to claim 1, wherein: The diameter of the semicircle at the upper right end of the magnetic sheet is 4.5 mm.

7. The novel magnetic focusing ring according to claim 6, wherein: The distance from the left edge of the upper end of the magnetic sheet to the center of the right circle is 28.25 mm, the distance from the upper boundary on the left to the lower boundary is 24.5 mm, and the width of the rectangle at the lower end on the left is 3 mm and the length is 4.6 mm.

8. A novel magnetic focusing ring according to any one of claims 1 to 7, characterized in that: The magnetic sheet material is selected from amorphous alloy, permalloy or silicon steel.

9. The novel magnetic focusing ring according to claim 8, wherein: The size of the magnetic focusing ring is 33x24.5mm, and the air gap distance is 4mm.

10. The novel magnetic focusing ring according to claim 9, wherein: Suitable for miniaturized scenarios.

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