A magnetic element anti-saturation core structure

Abstract

The application relates to a switching power supply device, in particular to a magnetic element anti-saturation magnetic core structure, which solves the technical problem that existing hard saturation magnetic elements are saturated under short-time high overvoltage or high overload working conditions, so that the switching power supply is difficult to stably work under the working conditions, the winding current of the magnetic element rapidly rises, and the switching is damaged. The magnetic element anti-saturation magnetic core structure comprises a winding, a magnetic yoke and a middle column forming a loop with the magnetic yoke; the distance between the winding and the middle column is d3; the length of the air gap is d1, and d3>=d1; the distance between the adjacent side walls of the hard saturation magnetic shunt and the soft saturation magnetic shunt is d2, and d2>=d1; the magnetic resistance R m2 of the soft saturation magnetic shunt is A times the magnetic resistance R m1 of the hard saturation magnetic shunt, and the value of A is greater than or equal to 5. The sum of the cross-sectional area A e1 of the hard saturation magnetic shunt and the cross-sectional area A e2 of the soft saturation magnetic shunt is less than or equal to the cross-sectional area A e3 of the magnetic yoke. The winding inductance is constant and does not change obviously with voltage or current under the rated working condition.

Description

Technical Field

[0001] This invention relates to a switching power supply device, specifically to a magnetic element anti-saturation core structure. Background Technology

[0002] Magnetic components are a common type of passive device in switching power supplies. Core saturation is typically determined by detecting changes in the inductance of the windings wound around the core. In most applications, core saturation causes a decrease in inductance, an increase in excitation current, increased winding losses, and even burnout. Therefore, rapid core saturation should be avoided.

[0003] Magnetic components are classified into two categories based on the properties of their core materials: hard-saturated and soft-saturated. Hard-saturated cores are characterized by a relative permeability μ of the core material. r The inductance is relatively large, generally greater than 500, such as manganese-zinc ferrite, silicon steel sheets, amorphous or microcrystalline materials, etc. Magnetic cores made of this type of hard-saturated material typically employ a concentrated air gap to suppress core saturation caused by voltage or current. The characteristic of this type of core is that before the winding voltage or current reaches its saturation value, the inductance formed by the winding and the core hardly changes with the voltage or current, remaining constant. When the winding voltage or current exceeds the saturation value, the inductance rapidly drops to a very small value, resulting in hard core saturation. See [link to documentation]. Figure 1 The characteristics of soft saturated magnetic cores are: the relative permeability μ of the material in this type of core is... r These are relatively small, generally ranging from tens to below 200, such as various magnetic powder cores, including iron powder cores, iron-silicon-aluminum powder cores, iron-silicon powder cores, iron-nickel powder cores, amorphous nanocrystalline powder cores, etc. These cores have a distributed air gap structure, and common permeabilities for these materials are 26, 40, 60, 75, 90, 125, etc. The winding inductance gradually decreases as the voltage or current increases. The inductance is related to the voltage or current value and is not a constant value. However, there will be no hard saturation phenomenon where the winding inductance rapidly drops to near zero after the voltage or current increases to a certain value. See [link to relevant documentation]. Figure 2 Both types of magnetic components have applications in the field of switching power supplies. For example, various transformers, LLC resonant inductors, and filter inductors generally require constant winding inductance and often employ hard-saturated magnetic cores. PFC inductors and BUCK / BOOST inductors, on the other hand, allow inductance to vary with voltage or current and often employ soft-saturated magnetic cores.

[0004] In power supply topologies requiring constant inductance of magnetic components, hard-saturated magnetic cores are typically used. Power supplies sometimes need to operate under short-term high-voltage (e.g., surges, mains voltage fluctuations) or high-current (e.g., overloads, short-circuit operation) conditions. When the voltage applied to the transformer is too high, or the current flowing through the inductor is too large, these magnetic cores can quickly hard-saturate, causing a rapid decrease in winding inductance and a rapid increase in winding current. This can easily lead to overcurrent damage to the main circuit switching transistors. To accommodate these short-term overvoltage and overload conditions, the conventional approach is to design a relatively low rated operating magnetic flux density for the magnetic components, ensuring that the core does not hard-saturate under short-term overvoltage and overload conditions. However, this results in larger, more expensive components, which is wasteful. Summary of the Invention

[0005] The purpose of this invention is to address the technical problem of existing hard-saturated magnetic components saturating under short-term high overvoltage or high overload conditions, making it difficult for switching power supplies to operate stably under such conditions. This leads to a rapid increase in winding current and damage to the switching transistor. The invention provides an anti-saturation magnetic core structure that ensures constant winding inductance below rated operating conditions, without significant changes in voltage or current. Under high overvoltage or high overload conditions, the winding inductance decreases slowly with voltage or current, rather than decreasing abruptly and causing a rapid increase in current.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] A magnetic element anti-saturation core structure, characterized in that it includes windings, a yoke, and a central column forming a circuit with the yoke;

[0008] The winding is wound around the outside of the center post, and the distance between the winding and the center post is d3;

[0009] The central column includes parallel hard saturation magnetic shunts and soft saturation magnetic shunts; the two ends of the hard saturation magnetic shunts and soft saturation magnetic shunts are respectively connected to the magnetic yoke;

[0010] The hard saturated magnetic shunt includes N+1 core segments, each core segment is coaxially arranged, and N air gaps are formed between adjacent core segments; N is a positive integer greater than or equal to 1; the length of the air gap along the axis of the hard saturated magnetic shunt is d1, and d3≥d1;

[0011] The distance between the hard saturated magnetic shunt and the soft saturated magnetic shunt relative to their adjacent walls is d2, and d2≥d1;

[0012] The reluctance R of a hard saturated magnetic shunt m1 The magnetic reluctance R of the soft saturation magnetic shunt m2 The relationship is R m2 =AR m1 The value of A is greater than or equal to 5;

[0013] Cross-sectional area A of hard saturated magnetic shunt core e1 Cross-sectional area A of soft saturated magnetic shunt core e2 With the cross-sectional area A of the magnetic yoke e3 The relationship between them is A e3 ≥A e1 +A e2 .

[0014] Furthermore, the magnetic yoke is a closed structure with an internal cavity;

[0015] Both the hard saturation magnetic shunt and the soft saturation magnetic shunt are located within the accommodating cavity, and the two ends of the hard saturation magnetic shunt and the soft saturation magnetic shunt are respectively connected to the magnetic yoke.

[0016] Alternatively, an air gap may be provided between one and / or both ends of the hard saturated magnetic shunt and the yoke; the two ends of the soft saturated magnetic shunt may be connected to the yoke respectively.

[0017] Furthermore, the magnetic yoke has a U-shaped structure;

[0018] The two ends of the hard saturated magnetic shunt and the soft saturated magnetic shunt are connected to the two ends of the magnetic yoke, respectively, to form a closed loop.

[0019] Furthermore, the magnetic yoke includes a first magnetic yoke and a second magnetic yoke that are parallel to each other;

[0020] Three sets of central columns (2) are arranged in parallel between the first magnetic yoke and the second magnetic yoke. The two ends of the hard saturation magnetic branch (3) and soft saturation magnetic branch (4) of each set of central columns (2) are connected to the first magnetic yoke and the second magnetic yoke, respectively.

[0021] Furthermore, the magnetoresistive R of the hard saturated magnetic shunt m1 :

[0022]

[0023] Where: N is the number of air gaps; μ0 is the air permeability;

[0024] Soft saturated magnetic shunt reluctance R m2 :

[0025]

[0026] In the formula: l g λ is the axial length of the soft saturation magnetic shunt. r The relative permeability of the magnetic material for a soft saturation magnetic shunt.

[0027] Furthermore, the hard saturated magnetic shunt includes three magnetic core segments, each magnetic core segment is coaxially arranged, and two air gaps are formed between adjacent magnetic core segments.

[0028] Furthermore, the value of A is 5.

[0029] Furthermore, the winding is made of Litz wire or thin copper foil.

[0030] Compared with the prior art, the beneficial effects of the technical solution of the present invention are:

[0031] 1. In the anti-saturation magnetic core structure of this invention, the inductance of the magnetic element hardly changes with voltage and current below rated operating conditions. Under high overvoltage and high overload conditions, the winding inductance decreases slowly with voltage or current, expanding the application environment of the switching power supply to adapt to a wide range of voltage and load changes, and preventing the power supply from exploding due to a rapid rise in current when the power supply output is short-circuited.

[0032] 2. Compared to traditional designs that rely solely on reducing the magnetic flux density of magnetic components and increasing the core size to adapt to a wide operating range of power supplies, this invention features minimal changes in the core size and a small increase in the amount of copper wire used in the windings, resulting in a smaller increase in cost and a simpler structural implementation.

[0033] 3. In this invention, the hard saturated magnetic shunt and the soft saturated magnetic shunt of the magnetic core structure (central column) maintain at least one air gap length distance. When the magnetic flux diffuses at the air gap of the hard saturated magnetic shunt, eddy current loss will not be generated in the magnetic core of the soft saturated magnetic shunt, resulting in low heat generation and high efficiency.

[0034] 4. In this invention, the soft saturation magnetic shunt and the hard saturation magnetic shunt are connected in parallel. Under long-term normal rated operating conditions, there is almost no magnetic flux in the soft saturation magnetic shunt, so there is no high-frequency eddy current loss, no additional heat generation, and high efficiency.

[0035] 5. The winding uses Litz wire or thin copper foil material with a thickness less than the skin depth, and should maintain at least one air gap length distance between it and both the hard saturation magnetic shunt and the soft saturation magnetic shunt. This can greatly reduce the eddy current loss of the air gap diffusion flux in the winding, resulting in less winding heat generation and higher efficiency.

[0036] 6. For large-gap magnetic elements, the present invention adopts a segmented air gap structure, which can reduce the eddy current loss of the magnetic core at the air gap. Attached Figure Description

[0037] Figure 1 This is a schematic diagram showing the characteristics of inductance as a function of magnetic field strength for an existing hard saturated magnetic element.

[0038] Figure 2 This is a schematic diagram showing the characteristics of inductance variation with magnetic field strength for an existing soft saturation magnetic element.

[0039] Figure 3 This is a schematic diagram of an embodiment of the anti-saturation magnetic core structure of the present invention, where lg represents the axial length of the soft saturation magnetic shunt core.

[0040] Figure 4 For this Figure 3 Top view.

[0041] Figure 5 This is a schematic diagram of the structure of the second embodiment of the anti-saturation magnetic core structure of the present invention.

[0042] Figure 6 This is a schematic diagram of the structure of the anti-saturation magnetic core structure of the present invention, in embodiment three.

[0043] The attached figures are labeled as follows:

[0044] 1-Magnetic yoke, 2-Center column, 3-Hard saturated magnetic shunt, 4-Soft saturated magnetic shunt, 5-Air gap, 6-Winding, 7-Core segment. Detailed Implementation

[0045] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the technical solution of the present invention. All other embodiments obtained by those skilled in the art based on the technical solution of the present invention without creative effort are within the scope of protection of the present invention.

[0046] In some switching power supply topologies, such as LLC and phase-shifted full-bridge topologies, the inductance must remain constant during normal operation. These topologies typically use ferrite cores, which are prone to hard saturation. When these topologies are subjected to short-term heavy overload or short-circuit operation, the current flowing through the inductor is very large, easily causing the core to saturate and resulting in a rapid decrease in inductance. The power supply control circuit's response speed and controllable steady-state range cannot adapt to this rapid change in inductance, leading to power supply runaway, a sharp rise in current, and ultimately, power supply failure.

[0047] This invention provides a magnetic element anti-saturation core structure, such as... Figure 3 As shown, it includes winding 6, yoke 1, and center column 2 forming a circuit with yoke 1;

[0048] The winding 6 is wound around the outside of the central column 2, and the distance between the winding 6 and the central column 2 is d3;

[0049] The central column 2 includes a parallel hard saturation magnetic branch 3 and a soft saturation magnetic branch 4; the two ends of the hard saturation magnetic branch 3 and the soft saturation magnetic branch 4 are respectively connected to the magnetic yoke 1.

[0050] The hard saturated magnetic shunt 3 includes N+1 magnetic core segments 7, each magnetic core segment 7 is coaxially arranged, and N air gaps 5 are formed between adjacent magnetic core segments 7; N is a positive integer greater than or equal to 1; the length of the air gap 5 along the axis of the hard saturated magnetic shunt 3 is d1, and d3≥d1;

[0051] The distance between the adjacent sidewalls of the hard saturated magnetic shunt 3 and the soft saturated magnetic shunt 4 is d2, and d2≥d1;

[0052] The reluctance R of hard saturated magnetic shunt 3 m1 The reluctance R of the soft saturation magnetic shunt 4 m2 The relationship is R m2 =AR m1 The value of A is greater than or equal to 5.

[0053] Hard saturated magnetic shunt 3 core cross-sectional area A e1 Soft saturated magnetic shunt 4 core cross-sectional area A e2 With the cross-sectional area A of the magnetic yoke 1 e3 The relationship between them is A e3 ≥A e1 +A e2 .

[0054] The design concept of the anti-saturation magnetic core structure of the magnetic element in this invention is as follows:

[0055] This invention employs a hybrid technical solution combining hard saturated magnetic shunt 3 and soft saturated magnetic shunt 4. Under normal rated operating conditions, the vast majority of magnetic flux flows only through the hard saturated magnetic shunt 3, thus the magnetic element exhibits external characteristics where the inductance of winding 6 hardly changes with voltage or current.

[0056] Under short-term high overvoltage or high overload conditions, the core of the hard saturation magnetic shunt 3 becomes saturated, and part of its magnetic flux is diverted to the soft saturation magnetic shunt 4. At this time, the magnetic element exhibits soft saturation characteristics. To achieve the above effect, the magnetic element design requires that the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 have a parallel structure on the magnetic circuit.

[0057] Under normal operating conditions, the soft saturation magnetic shunt 4 magnetoresistive R m2 It should be greater than or equal to the reluctance R of the hard saturated magnetic shunt. m1 At least five times, to ensure that the influence of the soft saturation magnetic shunt 4 on the inductance is within a controllable range. There should be at least one air gap 5 between the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 to reduce the high-frequency eddy current loss generated by the diffused magnetic flux at the air gap 5 of the hard saturation magnetic shunt 3 on the soft saturation magnetic shunt 4.

[0058] Compared to traditional magnetic element solutions where the cross-sectional area of ​​the yoke 1 and the central column 2 are the same (or only half, depending on the application of the magnetic core), the cross-sectional area A of the yoke 1 in this invention is... e3 It should be greater than the cross-sectional area A of the three cores in the hard saturation magnetic shunt. e1 The cross-sectional area A of the four magnetic cores in the soft saturation magnetic shunt e2The sum of these ensures that the magnetic core of the yoke 1 remains unsaturated under high overvoltage or high overload conditions. Simultaneously, the winding 6 wound on the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 should be at least one air gap 5 away from the sidewalls of the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 to reduce the high-frequency eddy current losses generated by the diffused magnetic flux at the air gap 5 on the winding 6.

[0059] The difference between this invention and common inductors lies in the addition of a soft saturation magnetic shunt 4 to the common hard saturation magnetic shunt 3. The hard saturation magnetic shunt 3 is made of a magnetic material with hard saturation characteristics, such as silicon steel sheet, amorphous or microcrystalline materials, or ferrite. The soft saturation magnetic shunt 4 is made of a magnetic material with soft saturation characteristics, such as a magnetic powder core. The winding 6 is wound simultaneously on the central column 2, which is composed of both the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4.

[0060] Example 1

[0061] like Figure 3 , Figure 4 The diagram shown is a cross-sectional schematic of the anti-saturation magnetic core structure of the magnetic element of the present invention. This embodiment takes a common single-phase E-type magnetic core as an example to further illustrate the technical solution of the present invention. The magnetic yoke 1 is a closed structure with an internal cavity; both the hard saturation magnetic branch 3 and the soft saturation magnetic branch 4 are located within the cavity, and the two ends of the hard saturation magnetic branch 3 and the soft saturation magnetic branch 4 are respectively connected to the magnetic yoke 1 (an air gap 5 can also be provided between one end of the hard saturation magnetic branch 3 and the magnetic yoke 1; the two ends of the soft saturation magnetic branch 4 are respectively connected to the magnetic yoke 1).

[0062] To reduce the length of a single air gap 5 and thus decrease eddy current losses at that air gap, the hard saturated magnetic shunt 3 is divided into three segments: a first core segment, a second core segment, and a third core segment. A first air gap is formed between the first and second core segments, and a second air gap is formed between the second and third core segments. The lengths of both the first and second air gaps along the axial direction of the hard saturated magnetic shunt 3 are d1. The distance between the adjacent sidewalls of the soft saturated magnetic shunt 4 and the hard saturated magnetic shunt 3 is d2, and d2 ≥ d1. This prevents the diffusion flux in the first and second air gaps of the hard saturated magnetic shunt 3 from inducing large eddy current losses in the soft saturated magnetic shunt 4.

[0063] The distance between winding 6 and the sidewalls of soft saturated magnetic shunt 4 and hard saturated magnetic shunt 3 is d3, where d3≥d1, which avoids large eddy current losses induced in winding 6 by the first and second air gaps of hard saturated magnetic shunt 3.

[0064] Hard saturated magnetic shunt 3 reluctance R m1 :

[0065]

[0066] Where: N is the number of air gaps;

[0067] d1 is the length of a single air gap 5;

[0068] μ0 is the air permeability;

[0069] A e1 is the core cross-sectional area of ​​hard saturated magnetic shunt 3.

[0070] Soft saturation magnetic shunt 4 reluctance R m2 :

[0071]

[0072] in:

[0073] l g The axial length of the soft saturation magnetic shunt is 4.

[0074] μ r The relative permeability of the magnetic material in soft saturation magnetic shunt 4;

[0075] A e2 The core cross-sectional area of ​​the soft saturation magnetic shunt 4 is given.

[0076] Through design, R m2 ≥5×R m1 It can be guaranteed that when the rated operating conditions are below, the inductance of winding 6 changes by ≤10% with voltage or current, which meets the requirement of common circuit topologies that the inductance error of magnetic components does not exceed 10%.

[0077] The cross-sectional area of ​​the magnetic yoke 1 is A e3 , so that A e3 ≥A e1 +A e2 This ensures that under high overvoltage or high overload conditions, when the hard saturation magnetic circuit 3 and the soft saturation magnetic circuit 4 enter the soft saturation working state, the magnetic core of the yoke 1 will not be hard saturated, will not generate excessive losses, and will not cause a rapid decrease in inductance due to the saturation of the magnetic core of the yoke 1.

[0078] Before the hard saturation magnetic shunt 3 saturates, the reluctance R of the hard saturation magnetic shunt 3... m1 Only soft saturation magnetic shunt 4 reluctance R m2 It is 1 / 5 or even less. Since the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 are connected in parallel, about 90% of the total magnetic flux flows through the hard saturation magnetic shunt 3. Therefore, before the hard saturation magnetic shunt 3 is saturated, the characteristics of the magnetic element are mainly determined by the hard saturation magnetic shunt 3, and the external performance is that the inductance hardly changes with the voltage or current.

[0079] When the hard saturation magnetic shunt 3 is saturated under high overvoltage or high overcurrent conditions, its magnetic reluctance R m1 It increases rapidly, approaching the order of magnitude of R. m2 , or more than Rm2 Larger magnetic flux is transferred from hard saturation magnetic circuit 3 to soft saturation magnetic circuit 4. This is because the cross-sectional area A of the magnetic yoke 1... e3 Cross-sectional area A of 3 cores in hard saturated magnetic shunt e1 The cross-sectional area A of the four magnetic cores in the soft saturation magnetic shunt e2 Since the sum of the two is large, the yoke 1 will not saturate, and its effect on the inductance can be ignored. The characteristics of the magnetic element are jointly determined by the hard saturation magnetic circuit 3 and the soft saturation magnetic circuit 4, and the overall external behavior is that the inductance decreases slowly with voltage or current.

[0080] Because soft saturated magnetic materials and winding 6 induce significant eddy current losses in high-frequency magnetic fields, they generate additional heat. In this invention, winding 6 and soft saturated magnetic shunt 4 are separated from hard saturated magnetic shunt 3 by a distance equal to at least the length of an air gap 5, reducing the high-frequency eddy current influence of diffused magnetic flux at the air gap 5.

[0081] Example 2

[0082] like Figure 5 As shown, the difference between Embodiment 2 and Embodiment 1 is that the magnetic yoke 1 has a U-shaped structure; the two ends of the hard saturated magnetic branch 3 and the soft saturated magnetic branch 4 are respectively connected to the two ends of the magnetic yoke 1 to form a closed loop. The opening of the magnetic yoke 1 is composed of a hard saturated magnetic branch 3 consisting of three magnetic core segments 7 (hard saturated segmented air gap 5 magnetic cores) and a soft saturated magnetic branch 4 consisting of soft saturated magnetic cores, with a winding 6 wound around it. The remaining magnetic yoke 1 is made of hard saturated magnetic material.

[0083] Under rated operating conditions, due to the low magnetic reluctance of the hard-saturated magnetic shunt 3, most of the magnetic flux passes through the hard-saturated magnetic shunt 3 and forms a closed loop with the U-shaped yoke 1. Only a small portion of the magnetic flux flows through the soft-saturated magnetic shunt 4, and the magnetic element exhibits hard-saturation characteristics. Under high overvoltage or high overload conditions, the magnetic flux in the hard-saturated magnetic shunt 3 becomes saturated, its magnetic reluctance increases, and the magnetic flux flows through both the hard-saturated magnetic shunt 3 and the soft-saturated magnetic shunt 4 simultaneously. The magnetic element then exhibits soft-saturation characteristics.

[0084] The remaining structures of Example 2 are the same as those of Example 1.

[0085] Example 3

[0086] like Figure 6As shown, the difference between Embodiment 3 and Embodiment 1 is that the magnetic yoke 1 includes a parallel first magnetic yoke and a second magnetic yoke; the central column 2 is disposed between the first magnetic yoke and the second magnetic yoke, and there are three groups, namely the first group of central columns, the second group of central columns, and the third group of central columns; one end of the first magnetic yoke and the second magnetic yoke are respectively connected to the two ends of the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 of the first group of central columns; the other end of the first magnetic yoke and the second magnetic yoke are respectively connected to the two ends of the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 of the third group of central columns; the second group of central columns is located between the first group of central columns and the third group of central columns, with one end connected to the first magnetic yoke and the other end connected to the second magnetic yoke; thus forming a three-phase E-type magnetic core structure. The three central columns 2 (composite magnetic core columns) are wound with the same three-phase A winding 6, three-phase B winding 6, and three-phase C winding 6, respectively.

[0087] Since the vector sum of the three-phase voltages or currents is equal to 0, when a voltage or current excitation with a 120° phase difference is applied to the three-phase A winding 6, the three-phase B winding 6, and the three-phase C winding 6, the resulting magnetic flux will form a closed loop through the three-phase composite magnetic shunt and the upper and lower magnetic yokes 1. Under rated operating conditions, because the magnetic reluctance of the hard saturation magnetic shunt 3 of each intermediate column 2 is small, most of the magnetic flux flows through this magnetic shunt, and the soft saturation magnetic shunt 4 connected in parallel with it is almost ineffective. Therefore, the magnetic element exhibits hard saturation characteristics externally.

[0088] When the magnetic component is subjected to high overvoltage or high overload, the magnetic flux of the hard saturation magnetic shunt 3 becomes saturated, the magnetic reluctance increases, and the magnetic flux flows through both the hard saturation magnetic shunt 3 and the soft saturation magnetic shunt 4 at the same time. The magnetic component then exhibits soft saturation characteristics.

[0089] The remaining structures of Example 3 are the same as those of Example 1.

Claims

1. A magnetic element anti-saturation core structure, characterized by: The winding (6), the yoke (1), and the column (2) form a loop. The winding (6) is wound on the outside of the column (2), and the distance between the winding (6) and the column (2) is d3. The column (2) includes a hard saturation magnetic shunt (3) and a soft saturation magnetic shunt (4) connected in parallel. The hard saturation magnetic shunt (3) includes N+1 magnetic core segments (7), each of which is coaxially arranged, and N air gaps (5) are formed between adjacent magnetic core segments (7). The distance between the hard saturation magnetic shunt (3) and the soft saturation magnetic shunt (4) is d2, and d2≥d1. The magnetic reluctance R of the hard saturated magnetic shunt (3) m1 The magnetic reluctance R of the soft saturation magnetic shunt (4) m2 The relationship is R m2 =AR m1 The value of A is greater than or equal to 5; The hard saturation magnetic shunt (3) has a magnetic resistance R m1 : In the formula: N is the number of air gaps (5); μ0 is the air permeability; The soft saturation magnetic shunt (4) magnetoresistance R m2 : where: l g is the axial length of the soft saturation magnetic shunt (4); μ r is the relative permeability of the magnetic material of the soft saturation magnetic shunt (4); The hard saturation magnetic shunt (3) core cross-sectional area A e1 The soft saturation magnetic shunt (4) core cross-sectional area A e2 The relationship between the magnetic yoke (1) cross-sectional area A e3 A e3 ≥ A e1 + A e2 .

2. A magnetic element anti-saturation core structure according to claim 1, wherein: The yoke (1) is a closed structure, and an accommodating cavity is arranged in the yoke (1). The hard saturation magnetic shunt (3) and the soft saturation magnetic shunt (4) are located in the accommodating cavity, and the two ends of the hard saturation magnetic shunt (3) and the soft saturation magnetic shunt (4) are connected with the yoke (1). Alternatively, one end or both ends of the hard saturation magnetic shunt (3) and the yoke (1) are provided with an air gap (5); and the two ends of the soft saturation magnetic shunt (4) are connected with the yoke (1).

3. The magnetic element anti-saturation core structure of claim 1, wherein: The yoke (1) is a U-shaped structure. The two ends of the hard saturation magnetic shunt (3) and the soft saturation magnetic shunt (4) are connected with the two ends of the yoke (1), forming a closed loop.

4. The magnetic element anti-saturation core structure of claim 1, wherein: The yoke (1) includes a first yoke and a second yoke parallel to each other. Three columns (2) are arranged in parallel between the first yoke and the second yoke, and the two ends of the hard saturation magnetic shunt (3) and the soft saturation magnetic shunt (4) of each column (2) are connected with the first yoke and the second yoke.

5. A magnetic element anti-saturation core structure as claimed in claim 4, wherein: The hard saturation magnetic shunt (3) includes three magnetic core segments (7), each of which is coaxially arranged, and two air gaps (5) are formed between adjacent magnetic core segments (7).

6. A magnetic element anti-saturation core structure as claimed in claim 5, wherein: The value of A is 5.

7. A magnetic element anti-saturation core structure as claimed in claim 6, wherein: The winding (6) uses Litz wire or thin copper foil.

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