Discrete magnetic circuit magnetic resistance optimized layered magnetic core structure for restraining size resonance

Abstract

The invention discloses a discrete magnetic circuit magnetic resistance optimized layered magnetic core structure for restraining size resonance, which comprises at least two magnetic core monomers which are sequentially and tightly nested from inside to outside, each magnetic core monomer continuously extends in a closed manner along the circumferential direction, and a compensation air gap is arranged at at least one preset circumferential position, so that a discrete air gap structure is formed; and in each discrete air gap structure, the physical lengths of the compensation air gaps of the magnetic core monomers are not completely equal. A traditional solid annular magnetic core is divided into a plurality of independent magnetic core single bodies in the radial direction, different air gap compensation is introduced into the single bodies, high-frequency magnetic flux distribution and an edge magnetic leakage path in the magnetic core are optimized from the mechanism, the trend that magnetic flux gathers to an inner ring is reduced on the premise that the overall dimension of the magnetic core is not changed, high-frequency loss is reduced, and the performance of the magnetic core is improved. And the inner ring is inhibited from being saturated in advance, so that the magnetic element can be more stably and efficiently applied to modern high-power power electronic technology occasions. The invention further discloses a magnetic element, a transformer and an inductor comprising the layered magnetic core structure.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology, specifically relating to a layered magnetic core structure with optimized discrete magnetic circuit reluctance to suppress size resonance, as well as magnetic components, transformers and inductors using this structure. Background Technology

[0002] In recent years, with the application of wide-bandgap semiconductor devices such as gallium nitride and silicon carbide, the operating frequency of modern power electronic converters is constantly developing towards megahertz (MHz) and higher frequencies. Under the trend of higher frequency and higher power density, magnetic components not only need to be smaller and more efficient, but also need to have stronger DC bias capability and more controllable temperature rise distribution, which puts forward higher requirements for core structure and air gap design.

[0003] Toroidal cores are one of the most widely used core structures, but in practical applications, especially in situations where a larger cross-section is required to carry higher power, they have an inherent physical defect: because the average magnetic path lengths at the inner and outer diameters of the toroidal core are naturally different, under the same magnetomotive force, the magnetic flux tends to be distributed along the path with the smaller equivalent magnetic reluctance, resulting in a significant non-uniform distribution of magnetic flux density on the cross-section. The inner ring is very prone to local overheating and premature magnetic saturation.

[0004] On the other hand, when the operating frequency increases to the megahertz (MHz) level, the propagation wavelength of electromagnetic waves inside the magnetic core is significantly shortened due to the extremely high permeability and dielectric constant of materials such as high-frequency power ferrites. When the physical cross-sectional size of the magnetic core is comparable to half the wavelength of the electromagnetic wave, a strong size resonance effect is easily induced. This causes the magnetic flux to form standing waves within the solid cross-section, leading to more severe local magnetic flux accumulation and a surge in high-frequency eddy current losses. The superposition of the above-mentioned differences in the inner and outer diameter magnetic circuits and the size resonance effect severely limits the overall DC bias capability and high-frequency power capacity of large-section devices.

[0005] In existing technologies, to address the issues of easy saturation of the inner ring and uneven magnetic flux density distribution in traditional solid toroidal magnetic cores, air gaps are typically introduced. This can be achieved by creating a single air gap notch in the toroidal core or by using a magnetic powder core material with an equivalent air gap distribution. These traditional solutions can significantly increase the total magnetic reluctance of the magnetic circuit by introducing air gaps, thereby reducing the overall effective permeability of the core. This improves the DC bias capability of the device while simultaneously reducing the peak magnetic flux density of the inner ring of the toroidal core.

[0006] However, for traditional air-gap designs, this increase in reluctance is often overall and cannot provide differentiated compensation for the radial reluctance of different annular cross-sections. Therefore, while these designs increase the total air-gap reluctance, the problems of flux concentration towards the inner ring and localized loss concentration remain severe. In high-power applications, designers often further increase the overall air gap to forcibly suppress localized saturation in the inner ring. This not only leads to an excessive decrease in core permeability but also causes severe magnetic leakage.

[0007] In summary, existing toroidal magnetic cores and traditional air-gap designs have inherent limitations in improving magnetic flux distribution. Constrained by differences in the magnetic circuits of the inner and outer diameters, the three-dimensional effect of the air gap, and high-frequency size resonance, existing solutions struggle to simultaneously achieve uniform magnetic flux density and suppress premature saturation of the inner ring. Therefore, this invention proposes a layered magnetic core structure and magnetic element with optimized discrete magnetic circuits to suppress size resonance. Summary of the Invention

[0008] The purpose of this invention is to provide a layered magnetic core structure with optimized discrete magnetic circuit reluctance to suppress size resonance. By dividing a traditional solid toroidal magnetic core radially into multiple independent magnetic core units and introducing different air gap compensations for each unit, the high-frequency magnetic flux distribution and edge leakage magnetic path inside the magnetic core are optimized from a mechanistic perspective. This structure enables the magnetic core to effectively reduce the tendency of magnetic flux to accumulate in the inner ring while maintaining the original outer dimensions, significantly reducing high-frequency losses and suppressing early saturation of the inner ring. This allows the magnetic components to be applied more stably and efficiently in modern high-power power electronics applications.

[0009] To achieve the above objectives, the solution of the present invention is:

[0010] A layered magnetic core structure for suppressing size resonance and optimizing the magnetic reluctance of discrete magnetic circuits includes at least two independent magnetic core units of different sizes that are tightly nested from the inside out. Each magnetic core unit extends continuously and closedly along the circumference. Each magnetic core unit has a compensation air gap at at least one preset circumferential position, so that all magnetic core units form discrete air gap structures at each preset circumferential position. In each discrete air gap structure, the physical lengths of the compensation air gaps of each magnetic core unit are not all equal.

[0011] Among them, the physical lengths of the compensation air gaps of each individual magnetic core are not all equal, including,

[0012] The average magnetic circuit length of the inner core unit is less than that of the outer core unit; the physical length of the compensation air gap of the inner core unit is greater than that of the compensation air gap of the outer core unit at the corresponding position.

[0013] The aforementioned compensation air gap is formed by the opposite arrangement of the disconnected end faces of the magnetic core units; the compensation air gaps of each magnetic core unit at the same preset circumferential position together form a stepped cut.

[0014] The physical length of the compensation air gap of each magnetic core unit is configured such that the total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located is equal or tends to be consistent within a preset error range; wherein, the total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located includes the body magnetic reluctance of the magnetic core unit and the three-dimensional air gap magnetic reluctance of the compensation air gap corresponding to the magnetic core unit.

[0015] The material of the aforementioned magnetic core unit is one or a combination of at least two of the following: manganese-zinc ferrite, nickel-zinc ferrite, amorphous magnetic material, or nanocrystalline magnetic material.

[0016] The aforementioned compensation air gap is filled with a low-permeability non-magnetic material, an insulating and thermally conductive material, or a cooling medium.

[0017] The aforementioned magnetic core unit is in the shape of a ring or rectangle.

[0018] A magnetic element includes at least one winding and a layered core structure as described above, the winding being surrounding the outside of the layered core structure.

[0019] A transformer or inductor comprising the magnetic element as described above.

[0020] After adopting the above scheme, the magnetic core body disclosed in this invention is composed of several independent magnetic core units of different sizes, nested sequentially from the inside out, forming discrete magnetic flux paths. To address the differences in the length of magnetic circuits at different levels, each magnetic core unit is provided with independently calculated compensating air gaps of varying lengths. This structure utilizes the principle of equal magnetoresistance to physically balance the magnetoresistance distribution of the magnetic flux cross-section. This invention solves the problems of magnetic flux accumulation and premature saturation caused by the short inner magnetic circuit and high-frequency size resonance effect in traditional solid magnetic cores, achieving uniform magnetic flux density distribution and maximizing material utilization, while significantly improving the thermal stability and power density of magnetic components.

[0021] Compared with existing technical solutions, the present invention has at least the following beneficial results:

[0022] (1) Suppressing size resonance and significantly reducing overall high-frequency magnetic loss. This invention physically disrupts the geometric conditions for size resonance of high-frequency electromagnetic waves by discretizing a large-section magnetic core into multiple thin-layer units. At the same time, with the inner-long and outer-short equal reluctance air gap design, the total reluctance of the branches where each core unit is located is forcibly balanced, so that the high-frequency magnetic flux is uniformly distributed across the entire core cross-section. This effectively suppresses the size resonance effect and magnetic flux accumulation phenomenon at high frequencies from a dual mechanism, weakens the excessively high local magnetic flux density, and thus significantly reduces the overall heat generation and loss of magnetic components under high-frequency operating conditions.

[0023] (2) Reduce local premature saturation and improve device power capacity. The equal reluctance configuration ensures that the inner and outer magnetic cores can reach the saturation critical point synchronously under the excitation action. This effectively alleviates the shortcoming that the inner ring of the traditional solid magnetic core is always the first to saturate, so that the magnetic core can safely carry higher DC bias current and operating power under the same cross-sectional area.

[0024] (3) Improved heat dissipation performance. The uniform magnetic flux distribution results in more uniform internal heat generation, which greatly alleviates the problem of local hot spots caused by the high concentration of inner ring losses in traditional solid magnetic cores. This significantly improves the overall thermal stability and operational reliability of magnetic components under high-frequency and high-power conditions.

[0025] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the layered magnetic core structure and discrete air gap configuration according to Embodiment 1 of the present invention;

[0027] Figure 2 This is a schematic diagram of the internal structure of the layered magnetic core according to Embodiment 1 of the present invention;

[0028] Among them, (a) is a schematic diagram of the combined structure of each layer of magnetic core, and (b) is a schematic diagram of the equivalent magnetic circuit of the magnetic core structure;

[0029] Figure 3 It is a magnetic density cloud diagram of a traditional solid circular toroidal core under the same working conditions;

[0030] Figure 4 It is a magnetic density cloud diagram of a circular ring magnetic core with a uniform air gap structure under the same working conditions;

[0031] Figure 5 It is a magnetic density cloud map of a layered magnetic core structure based on discrete magnetic circuit reluctance optimization under the same working conditions;

[0032] Figure 6 It is a comparison diagram of normalized magnetic flux density distribution along the radius of the magnetic core, used to compare the uniformity of magnetic flux distribution of traditional circular toroidal magnetic cores, uniform air gap magnetic cores and the discrete reluctance optimized structure of the present invention.

[0033] Figure 7 This is a schematic diagram of a layered magnetic core structure with multiple discrete air gaps provided in Embodiment 2 of the present invention;

[0034] Figure 8 This is a schematic diagram of the rectangular layered magnetic core structure provided in Embodiment 3 of the present invention. Detailed Implementation

[0035] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention provides a layered magnetic core structure for suppressing size resonance and optimizing the reluctance of discrete magnetic circuits. The structure includes a ring-shaped magnetic core body with an outer diameter, an inner diameter, and an axial height. The ring-shaped magnetic core body is composed of at least two independent magnetic core units of different sizes, nested tightly from the inside out, with each core unit extending continuously in the circumferential direction. The ring-shaped magnetic core body includes at least one discrete air gap structure located at a predetermined circumferential position. The discrete air gap structure includes compensation air gaps independently configured for each core unit, and the lengths of the compensation air gaps corresponding to different core units are not all equal. For example, a longer compensation air gap is configured for the inner core unit with a shorter average magnetic circuit, and a shorter compensation air gap is configured for the outer core unit with a longer average magnetic circuit, to differentiate the total reluctance of the magnetic circuit branches where each core unit is located. By calculating different air gap compensations, the equivalent total reluctance of each layer of core units can be made to approach equality.

[0037] Among the magnetic core units nested sequentially from the inside out, the average magnetic circuit length of the inner magnetic core unit is less than that of the outer magnetic core unit; in order to make the total magnetic reluctance of the magnetic circuit branches of each magnetic core unit more consistent, the physical length of the compensation air gap corresponding to the inner magnetic core unit is greater than that of the compensation air gap corresponding to the outer magnetic core unit.

[0038] The discrete air gap structure is formed by the opposite arrangement of the broken end faces of the annular magnetic core body; the broken end faces of each magnetic core individual at the preset circumferential position cooperate with each other to form a stepped cut, so as to form the compensation air gap of different lengths at different radial positions.

[0039] The total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located includes the body magnetic reluctance of the magnetic core unit and the three-dimensional air gap magnetic reluctance of the compensation air gap corresponding to the magnetic core unit; the length of the compensation air gap is configured to make the total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located equal or tend to be consistent within a preset error range.

[0040] The material of the magnetic core unit includes any one or more of manganese-zinc ferrite, nickel-zinc ferrite, amorphous magnetic materials, or nanocrystalline magnetic materials.

[0041] The compensation air gap is filled with a low-permeability non-magnetic material, an insulating and thermally conductive material, or a cooling medium.

[0042] Example 1:

[0043] Please see Figure 1 and Figure 2 This embodiment provides a layered magnetic core structure, which includes a ring-shaped magnetic core body composed of three independent magnetic core units of different sizes, nested tightly from the inside out: an inner magnetic core a, a central magnetic core b, and an outer magnetic core c; each layer of magnetic cores extends continuously and closedly along the circumference. The ring-shaped magnetic core body has discrete air gap structures at preset circumferential positions. These discrete layered air gap structures include compensation air gaps a, b, and c, corresponding to magnetic cores a, b, and c, respectively. To ensure that the total magnetic reluctance of the branches containing magnetic core units at different radial positions tends to be consistent, the physical lengths of each compensation air gap are set to unequal values ​​according to the equal magnetic reluctance condition. The discrete layered air gap structure forms a stepped cut through the air gaps of each magnetic core unit, thereby achieving different magnetic reluctance adjustments for different radial magnetic flux branches within the same region.

[0044] Figure 2 (b) is a schematic diagram of the equivalent magnetic circuit of the magnetic core structure. In this magnetic circuit model, each layer of the magnetic core is abstracted as an independent parallel branch. , , These represent the intrinsic magnetic reluctance of the materials used in magnetic cores a, b, and c, respectively. , , These represent the magnetic reluctance of the compensating air gaps configured on each layer of the magnetic core, with the circular symbol representing the equivalent excitation source. The magnetic core is discretized radially into three parallel magnetic circuit branches. By adjusting the length of the compensating air gaps, the total magnetic reluctance of each branch tends to be consistent.

[0045] Regarding the technical solution of this embodiment, in order to further verify the magnetic flux density homogenization effect based on discrete magnetic circuit equal reluctance optimization, such as Figures 3 to 6 As shown, this embodiment uses a two-layer tightly nested layered magnetic core structure as an example for specific simulation illustration. The simulation model uses the parameters of high-frequency power ferrite material for setting. Specifically, this embodiment selects a magnetic core with an outer diameter of 100mm, an inner diameter of 50mm, and a core height of 50mm, dividing it into inner and outer core units. Under the condition of winding turns N=4, this embodiment compares and simulates a traditional solid toroidal magnetic core, a toroidal magnetic core with a uniform air gap, and the discrete reluctance optimized structure of this embodiment.

[0046] like Figure 3As shown, traditional solid toroidal magnetic cores exhibit significant radial non-uniform magnetic flux density distribution under the same excitation conditions, with the magnetic flux density highly concentrated in the inner ring of the core. This leads to increased localized high losses and a greater risk of premature localized saturation. Furthermore, as... Figure 4 As shown, under the same operating conditions, although the uniform air gap structure can increase the overall magnetic reluctance, its magnetic flux density distribution still has significant deviations due to the lack of targeted compensation for differences in radial magnetic circuit lengths; for example... Figure 5 As shown, this embodiment divides the toroidal core body into inner and outer core units, and configures compensating air gaps with a longer inner core and a shorter outer core at the same disconnection point, precisely matching the total magnetic reluctance of the branches where the inner and outer core units are located. Simulation results clearly show that the structure of this embodiment significantly improves the uniformity of magnetic flux density distribution across the core cross-section and greatly alleviates the phenomenon of magnetic flux concentration towards the inner ring.

[0047] like Figure 6 As shown in the comparison curves of normalized magnetic flux density along the radial direction of the magnetic core, the two-layer structure provided in this embodiment can significantly reduce the highest point of magnetic flux density inside the magnetic core, making the magnetic field distribution along the radial direction smoother and more uniform. This not only effectively reduces local high-frequency heat loss and prevents the generation of hot spots, but also allows for more complete utilization of the entire magnetic core material, thereby further improving the overall power capacity that the device can withstand.

[0048] Example 2:

[0049] Please see Figure 7 This embodiment provides a layered magnetic core structure with multiple discrete air gaps. Based on Embodiment 1, this embodiment divides the annular magnetic core body into four independent arc-shaped blocks circumferentially. Discrete air gap structures are provided at the mating surfaces of adjacent arc-shaped blocks. In each discrete air gap structure, the compensation air gap corresponding to each layer of magnetic core unit still strictly follows the aforementioned equal reluctance configuration principle: the inner magnetic core unit corresponds to a longer compensation air gap, and the outer magnetic core unit corresponds to a shorter compensation air gap. By distributing the total air gap length to four circumferentially disconnected positions, this embodiment can better maintain a uniform distribution of magnetic flux density across the entire cross-section.

[0050] Example 3:

[0051] Please see Figure 8 The layered design based on discrete magnetic circuit isoresistive optimization proposed in this invention is not limited to ring structures, but is also applicable to other closed magnetic circuit configurations. This embodiment provides a rectangular layered magnetic core structure.

[0052] The magnetic core body is also composed of at least two layers of independent rectangular magnetic core units of different sizes, tightly nested from the inside out. Each magnetic core unit has a different discrete air gap structure, and the inner and outer layers of this structure exhibit clear stepped cuts. To achieve the principle of equal magnetic reluctance, the inner magnetic core units closer to the inner window of the rectangle have a longer compensating air gap, while the outer magnetic core units farther from the inner window have a shorter compensating air gap. This embodiment can also maintain a relatively uniform distribution of magnetic flux density across the entire cross-section.

[0053] Example 4:

[0054] This embodiment provides a magnetic element, which includes at least one winding and a layered magnetic core structure. The winding is wrapped around the outside of the layered magnetic core structure, and the layered magnetic core structure adopts the structure provided in any of the foregoing embodiments.

[0055] Example 5:

[0056] This embodiment provides a transformer or inductor that includes the magnetic element described in Embodiment 4.

[0057] In summary, this invention solves the problem of flux concentration and localized loss surges caused by the difference in length between the inner and outer magnetic circuits under high-frequency, high-power excitation in traditional solid magnetic cores through an innovative layered structure design based on discrete magnetic circuits and equal reluctance air gap optimization. By introducing stepped air gaps with longer inner and shorter outer layers in different nested layers, this invention fundamentally optimizes the internal high-frequency flux path and edge leakage magnetic field distribution, achieving uniform flux across the entire cross-section, a significant reduction in high-frequency loss, and effective suppression of localized premature saturation. This high-frequency characteristic optimization capability based on a passive physical underlying structure completely breaks through the physical limitations of traditional integral air gap designs, providing a new technical approach to improving the working capacity, operating efficiency, and thermal stability of modern high-frequency magnetic components.

[0058] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0059] For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances. When an element is referred to as being "assembled on," "mounted on," "fixed to," or "set on" another element, it may be directly on the other element or there may be an intermediate element present. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible embodiments.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

[0061] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

Claims

1. A layered magnetic core structure with optimized discrete magnetic circuit reluctance to suppress size resonance, characterized in that: It includes at least two independent magnetic core units of different sizes that are tightly nested from the inside out, and each magnetic core unit extends continuously in a closed manner along the circumference; each magnetic core unit has a compensation air gap at at least one preset circumferential position, so that all magnetic core units form discrete air gap structures at each preset circumferential position; in each discrete air gap structure, the physical length of the compensation air gap of each magnetic core unit is not all equal.

2. The layered magnetic core structure as described in claim 1, characterized in that: The physical lengths of the compensation air gaps in each individual magnetic core are not all equal, including: The average magnetic circuit length of the inner core unit is less than that of the outer core unit; the physical length of the compensation air gap of the inner core unit is greater than that of the compensation air gap of the outer core unit at the corresponding position.

3. The layered magnetic core structure as described in claim 1, characterized in that: The compensation air gap is formed by the opposite arrangement of the broken end faces of the magnetic core units; the compensation air gaps of each magnetic core unit at the same preset circumferential position together form a stepped cut.

4. The layered magnetic core structure as described in claim 1, characterized in that: The physical length of the compensation air gap of each magnetic core unit is configured such that the total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located is equal or tends to be consistent within a preset error range; wherein, the total magnetic reluctance of the magnetic circuit branch where each magnetic core unit is located includes the body magnetic reluctance of the magnetic core unit and the three-dimensional air gap magnetic reluctance of the compensation air gap corresponding to the magnetic core unit.

5. The layered magnetic core structure as described in claim 1, characterized in that: The magnetic core unit is made of one or a combination of at least two of the following: manganese-zinc ferrite, nickel-zinc ferrite, amorphous magnetic materials, or nanocrystalline magnetic materials.

6. The layered magnetic core structure as described in claim 1, characterized in that: The compensation air gap is filled with a low-permeability non-magnetic material, an insulating and thermally conductive material, or a cooling medium.

7. The layered magnetic core structure as described in claim 1, characterized in that: The magnetic core unit is generally ring-shaped or rectangular.

8. A magnetic element, characterized in that: It includes at least one winding and a layered core structure as described in any one of claims 1 to 7, wherein the winding surrounds the outside of the layered core structure.

9. A transformer or inductor, characterized in that: Includes the magnetic element as described in claim 8.

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