CN-122000171-A - Discrete magnetic circuit reluctance-optimized layered magnetic core structure for inhibiting size resonance

Abstract

The invention discloses a layered magnetic core structure for inhibiting size resonance and optimizing magnetic resistance of a discrete magnetic circuit, which comprises at least two magnetic core monomers which are sequentially and closely nested from inside to outside, wherein each magnetic core monomer continuously and closely extends along the circumferential direction, and a compensating air gap is arranged at least one preset circumferential position, so that a discrete air gap structure is formed, and the physical lengths of the compensating air gaps of each magnetic core monomer are not completely equal in each discrete air gap structure. The invention radially divides the traditional solid annular magnetic core into a plurality of independent magnetic core monomers, introduces different air gap compensation to each monomer, optimizes the high-frequency magnetic flux distribution and the edge magnetic leakage path inside the magnetic core in mechanism, reduces the tendency of the magnetic flux to gather to the inner ring on the premise of unchanged outline size of the magnetic core, reduces the high-frequency loss, and inhibits the early saturation of the inner ring, so that the magnetic element can be more stably and efficiently applied to the modern high-power electronic technical occasion. The invention also discloses a magnetic element, a transformer and an inductor comprising the layered magnetic core structure.

Inventors

• Shen zhan
• WANG NINGRUI
• LIU KAIYUAN
• CHEN WU
• WANG JIANGFENG
• LI XIN
• WU HENG
• LAN JIANXI
• JIN LONG

Assignees

• 东南大学

Dates

Publication Date

20260508

Application Date

20260303

Claims (9)

1. 1. A layered magnetic core structure for restraining size resonance and optimizing magnetic resistance of a discrete magnetic circuit is characterized by comprising at least two independent magnetic core monomers which are different in size and are tightly nested in sequence from inside to outside, wherein each magnetic core monomer continuously and closely extends along the circumferential direction, each magnetic core monomer is provided with a compensation air gap at least one preset circumferential position, and therefore all the magnetic core monomers correspondingly form a discrete air gap structure at each preset circumferential position, and the physical lengths of the compensation air gaps of each magnetic core monomer are not all equal in each discrete air gap structure.
2. 2. The layered magnetic core structure of claim 1, wherein the compensating air gaps of each magnetic core element are not all equal in physical length, comprising, The average magnetic path length of the magnetic core monomer positioned at the inner side is smaller than that of the magnetic core monomer positioned at the outer side, and the physical length of the compensating air gap of the magnetic core monomer positioned at the inner side is larger than that of the compensating air gap of the magnetic core monomer positioned at the corresponding position.
3. 3. The layered magnetic core structure of claim 1, wherein the compensating air gaps are formed by opposing disconnected end surfaces of the magnetic core units, and the compensating air gaps of the magnetic core units at the same preset circumferential position form a step-shaped notch.
4. 4. The layered magnetic core structure of claim 1, wherein the physical length of the compensating air gap of each magnetic core element is configured to equalize or tend to be uniform within a predetermined error range, and wherein the total magnetic resistance of the magnetic circuit branch of each magnetic core element comprises the bulk magnetic resistance of the magnetic core element and the three-dimensional air gap magnetic resistance of the compensating air gap corresponding to the magnetic core element.
5. 5. The layered magnetic core structure of claim 1, wherein the magnetic core unit is made of one or a combination of at least two of Mn-Zn ferrite, ni-Zn ferrite, amorphous magnetic material and nanocrystalline magnetic material.
6. 6. The layered magnetic core structure of claim 1, wherein the compensating air gap is filled with a low permeability non-magnetic material, an insulating thermally conductive material, or a cooling medium.
7. 7. The layered magnetic core structure of claim 1, wherein the magnetic core unit is in a ring-shaped or rectangular shape as a whole.
8. 8. A magnetic component comprising at least one winding and a layered magnetic core structure as claimed in any one of claims 1 to 7, said winding being wound around the outside of said layered magnetic core structure.
9. 9. A transformer or inductor comprising the magnetic element of claim 8.

Description

Discrete magnetic circuit reluctance-optimized layered magnetic core structure for inhibiting size resonance Technical Field The invention belongs to the technical field of power electronics, and particularly relates to a layered magnetic core structure for inhibiting size resonance and optimizing discrete magnetic circuit magnetic resistance, and a magnetic element, a transformer and an inductor adopting the structure. Background 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 continuously moving toward megahertz (MHz) and higher. Under the trend of high frequency and high power density, the magnetic element is required to be smaller in size and higher in efficiency, and also has stronger direct current bias capability and more controllable temperature rise distribution, which puts higher demands on the magnetic core structure and the air gap design. The ring-shaped magnetic core is one of the most widely used magnetic core structures, but in practical application, particularly in the situation that a larger section is needed to bear higher power, the ring-shaped magnetic core has an inherent physical defect that under the action of the same magnetomotive force, magnetic flux tends to be distributed along a path with smaller equivalent magnetic resistance due to the fact that the average magnetic path lengths at the inner diameter and the outer diameter of the ring-shaped magnetic core are naturally different, so that the magnetic flux density is obviously unevenly distributed on the section, and local temperature rise and advanced magnetic saturation of the inner ring are extremely easy to occur. On the other hand, when the operating frequency is raised to the megahertz (MHz) level, since materials such as high-frequency power ferrite generally have extremely high permeability and permittivity, the propagation wavelength of electromagnetic waves inside the core is greatly shortened. When the physical cross-sectional size of the magnetic core is comparable to the half wavelength of the electromagnetic wave, a strong size resonance effect is extremely easily induced. This results in the formation of standing waves of magnetic flux in the solid cross-section, causing more severe local flux concentrations and high frequency eddy current losses to proliferate. The superposition of the difference of the inner and outer diameter magnetic circuits and the size resonance effect makes the whole direct current bias capacity and the high-frequency power capacity of the large-section device severely limited. In the prior art, in order to solve the problems that the inner ring of the traditional solid annular magnetic core is easy to saturate and the magnetic density is unevenly distributed, a scheme of introducing an air gap is generally adopted on the basis, such as a single air gap notch is formed on the annular magnetic core, or a magnetic powder core material with an equivalent distributed air gap is adopted. The traditional scheme can greatly increase the total magnetic resistance of the magnetic circuit by introducing an air gap, and lower the overall effective magnetic conductivity of the magnetic core, so that the device DC bias capability is improved, and the peak magnetic density of the inner ring of the annular magnetic core is reduced. However, for conventional air gap solutions, this increase in reluctance tends to be integral and does not allow differential compensation of the annular cross-section for different radial reluctance. Therefore, these solutions still have serious problems of flux concentration to the inner ring and local loss concentration while improving the total air gap reluctance. In the case of higher power, in order to forcibly suppress the local saturation of the inner ring, the designer tends to continuously increase the overall air gap, which not only causes excessive decrease in magnetic permeability of the magnetic core, but also causes serious magnetic leakage effect. In summary, the annular magnetic core and the conventional air gap design in the prior art have inherent defects in improving the magnetic flux distribution, and under the common constraints of the difference of the inner and outer diameter magnetic circuits and the air gap three-dimensional effect and the high-frequency size resonance effect, the prior art has difficulty in considering the uniformity of the magnetic density and the restraint of the advanced saturation of the magnetic density of the inner ring. Therefore, the invention provides a layered magnetic core structure and a magnetic element for inhibiting magnetic resistance optimization such as a discrete magnetic circuit and the like of size resonance. Disclosure of Invention The invention aims to provide a layered magnetic core structure for inhibiting size resonance discrete magnetic circuit magnetic resistance optim