Permanent magnet mixed core magnetic element

Abstract

The disclosed embodiments may include systems and methods of permanent magnet (PM) hybrid core inductors and methods of making the same. The permanent magnet hybrid core may include a first set of members including a soft magnetic material, the first set of members forming a first gap between two end faces of the first set of members, and a second set of members including a permanent magnet material and positioned adjacent to the first set of members, the second set of members provides a path for the flow of the magnetic flux lines that is at least partially parallel to the first set of members. Some embodiments may include an inductor including a permanent magnet hybrid core, or a power conversion circuit including a switched capacitor circuit and a switching regulator, the switching regulator including an inductor including an electrical conductor wound around the permanent magnet hybrid core.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 63 / 366,620, filed on June 17, 2022, the entire contents of which are incorporated herein by reference for all purposes. Technical Field

[0003] The present disclosure relates generally to power electronics devices. More particularly, the present disclosure relates to voltage converter and / or regulator devices having high energy storage and low conduction losses. Background Art

[0004] As integrated circuit technology and computing power advance, the demand for power conversion, regulation and its management has grown accordingly. For power electronic devices such as converters or input filters that operate in continuous conduction mode at large dc currents, the storage density of the inductor can be enhanced by using core materials with high saturation flux density. However, for high-frequency operation in the MHz range and above, conduction and core losses may also increase with the applied dc bias, limiting the performance of the inductor. Although ferrites exhibit low core losses at high frequencies, they suffer from low saturation flux density. Therefore, it may be desirable to provide an inductor design with high energy storage, high saturation flux, low dc conduction losses and / or low ac-related losses including low ac conduction losses. Summary of the invention

[0005] Embodiments of the present disclosure provide a permanent magnet (PM) hybrid core inductor and a method for manufacturing the same. One aspect of the present disclosure relates to a magnetic core. The magnetic core may include a first set of components and a second set of components, the first set of components including a soft magnetic material, the first set of components forming a first gap between two end faces of the first set of components, the second set of components including a permanent magnetic material and positioned adjacent to the first set of components, wherein the second set of components provides a path for the flow of magnetic flux lines at least partially parallel to the first set of components.

[0006] Another aspect of the present disclosure relates to a magnetic core. The magnetic core may include a permanent magnet having a curved surface and a soft magnetic member positioned adjacent to the curved surface of the permanent magnet. The soft magnetic member may form a first gap between two end faces of the soft magnetic member and may provide a hollow space for winding an electrical conductor around the permanent magnet. The permanent magnet may provide a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic member.

[0007] Yet another aspect of the present disclosure relates to an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a first set of components and a second set of components, the first set of components including a soft magnetic material, the first set of components forming a first gap between two end faces of the first set of components, the second set of components including a permanent magnetic material and positioned adjacent to the first set of components, wherein the second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

[0008] Yet another aspect of the present disclosure relates to an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a permanent magnet having a curved surface and a soft magnetic member positioned adjacent to the curved surface of the permanent magnet. The soft magnetic member may form a first gap between two end faces of the soft magnetic member, and may provide a hollow space for the electrical conductor to be wound around the permanent magnet. The permanent magnet may provide a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic member.

[0009] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a switching voltage regulator including an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a first set of components and a second set of components, the first set of components including a soft magnetic material, the first set of components forming a first gap between two end faces of the first set of components, and the second set of components including a permanent magnetic material and positioned adjacent to the first set of components, wherein the second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

[0010] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a switching voltage regulator including an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a permanent magnet having a curved surface and a soft magnetic member positioned adjacent to the curved surface of the permanent magnet. The soft magnetic member may form a first gap between two end faces of the soft magnetic member and may provide a hollow space for winding the electrical conductor around the permanent magnet. The permanent magnet may provide a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic member.

[0011] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a power conversion circuit including an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a first set of components and a second set of components, the first set of components including a soft magnetic material, the first set of components forming a first gap between two end faces of the first set of components, and the second set of components including a permanent magnetic material and positioned adjacent to the first set of components, wherein the second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

[0012] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a power conversion circuit including an inductor. The inductor may include an electrical conductor wound around a magnetic core. The magnetic core may include a permanent magnet having a curved surface and a soft magnetic member positioned adjacent to the curved surface of the permanent magnet. The soft magnetic member may form a first gap between two end faces of the soft magnetic member and may provide a hollow space for winding the electrical conductor around the permanent magnet. The permanent magnet may provide a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic member.

[0013] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a power conversion circuit, the power conversion circuit including a switched capacitor circuit and a switching regulator, the switching regulator including an inductor, the inductor including an electrical conductor wound around a magnetic core. The magnetic core may include a first set of components and a second set of components, the first set of components including a soft magnetic material, the first set of components forming a first gap between two end faces of the first set of components, the second set of components including a permanent magnetic material and positioned adjacent to the first set of components, wherein the second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

[0014] Yet another aspect of the present disclosure relates to an apparatus. The apparatus may include a power conversion circuit including a switched capacitor circuit and a switching regulator including an inductor including an electrical conductor wound around a magnetic core. The magnetic core may include a permanent magnet having a curved surface and a soft magnetic member positioned adjacent to the curved surface of the permanent magnet. The soft magnetic member may form a first gap between two end faces of the soft magnetic member, and may provide a hollow space for winding the electrical conductor around the permanent magnet. The permanent magnet may provide a path at least partially parallel to the soft magnetic member for the flow of magnetic flux lines.

[0015] Additional features and advantages of the disclosed embodiments will be explained in part in the following description, and in part will become apparent from the description, or can be understood by the practice of the embodiments. The features and advantages of the disclosed embodiments can be realized and obtained by the elements and combinations set forth in the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Embodiments and various aspects of the present disclosure are shown in the following detailed description and accompanying drawings. Note that, in accordance with standard practice in the industry, various features are not drawn to scale. In fact, the size of various features may be arbitrarily increased or reduced for clarity of discussion.

[0017] Figure 1 is a schematic diagram of an exemplary multi-level power converter circuit according to some embodiments of the present disclosure.

[0018] Figure 2Shown are representations of an exemplary response (solid line) and an expected response (dashed line) of a magnetic material to an external magnetic field according to some embodiments of the present disclosure.

[0019] Figure 3 is a schematic diagram of an exemplary inductor design with a permanent magnet hybrid core according to an embodiment of the present disclosure.

[0020] Figure 4 is a schematic diagram of an exemplary magnetic circuit model of a permanent magnet hybrid core according to an embodiment of the present disclosure.

[0021] Figure 5A and Figure 5B Graphs of simulation data showing the optimum ferrite fraction and maximum flux carrying capacity of a permanent magnet hybrid core using a modified model and an ideal model, respectively, according to an embodiment of the present disclosure.

[0022] Fig. 6A is a schematic diagram of an exemplary magnetic core according to an embodiment of the present disclosure.

[0023] FIG. 6B to FIG. 6J is a schematic diagram of an exemplary implementation of a permanent magnet hybrid core in a parallel configuration according to an embodiment of the present disclosure.

[0024] Figure 7 is a schematic diagram of an exemplary implementation of one half of a dual U-shaped inductor core in a non-parallel configuration according to an embodiment of the present disclosure.

[0025] Fig. 8A is a schematic diagram of a perspective view of an exemplary permanent magnet hybrid core inductor according to an embodiment of the present disclosure.

[0026] Figure 8B According to the embodiments of the present disclosure, Fig. 8A Schematic diagram of a cross-sectional view of an exemplary permanent magnet hybrid core inductor with section AA′ shown in FIG.

[0027] Fig. 9 is a schematic diagram of windings and permanent magnet flux paths in an exemplary permanent magnet hybrid core inductor according to an embodiment of the present disclosure.

[0028] Fig.10 Data graphs representing simulated and measured saturation behavior of permanent magnet hybrid core and pure ferrite core inductors are shown in accordance with embodiments of the present disclosure.

[0029] Fig.11 An exemplary data graph showing measured inductance over a frequency range for permanent magnet hybrid core and pure ferrite core inductors according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] The following disclosure provides many different exemplary embodiments or examples for realizing the different features of the provided subject matter. Specific simplified examples of components and arrangements are described below to illustrate the present disclosure. Of course, these are merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and / or letters in various examples. This repetition is for simplicity and clarity purposes, and does not itself specify the relationship between the various embodiments and / or configurations discussed.

[0031] The terms used in this specification generally have their ordinary meanings in the art and in the specific context in which each term is used. The use of examples in this specification (including examples of any term discussed herein) is illustrative only and in no way limits the scope and meaning of the present disclosure or the scope and meaning of any exemplary term. Likewise, the present disclosure is not limited to the various embodiments given in this specification.

[0032] Although the terms "first", "second", etc. may be used to describe various elements in this article, these elements should not be limited by these terms. These terms are used to distinguish one element from another element. For example, without departing from the scope of the embodiment, the first element may be referred to as the second element, and similarly, the second element may be referred to as the first element. As used herein, the term "and / or" includes any and all combinations of one or more of the items listed in association.

[0033] Additionally, for ease of description, spatially relative terms such as "below," "below," "below," "above," and the like may be used herein to describe the relationship of one element or feature to another (or other) elements or features as illustrated in the drawings. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the drawings. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0034] Some embodiments of the present invention may allow for better implementation of passive components in power converters, which may ease the performance requirements on active components such as switching components.

[0035] Various non-limiting embodiments of the present disclosure will be described for embodiments in a specific context (i.e., high-density and high-efficiency voltage regulation devices). As used in the present disclosure, the term "voltage regulator" refers to a component of a power supply unit (PSU) configured to convert an input voltage into a stable output voltage. Although most voltage regulators can be used for DC-DC power conversion, some voltage regulators can also be used for AC-DC power conversion or AC-AC power conversion. A linear voltage regulator can be configured to output a lower stable voltage signal from a higher voltage signal. In some cases, a linear voltage regulator can utilize input and output capacitors or an active pass device (active pass device) (such as a bipolar junction transistor (BJT) or a metal oxide semiconductor field effect transistor (MOSFET)) to regulate voltage. However, with the help of additional external components such as an inductor, a capacitor, a FET or a feedback resistor, a switching voltage regulator can be configured as a drop type (buck converter), a rise type (boost converter) or a buck-boost converter.

[0036] In some cases, the power converter can be used as a voltage regulator. The concepts in the present disclosure can be applied to voltage regulators or power converters. A power converter that converts a higher input voltage power supply to a lower output voltage level can be referred to as a step-down or buck converter because the converter "steps down" the input voltage. A power converter that converts a lower input voltage power supply to a higher output voltage level can be referred to as a step-up or boost converter because the converter "steps up" the input voltage. In addition, some power converters (commonly referred to as "buck-boost converters") can be configured to convert an input voltage power supply to an output voltage with a wide range, wherein the output voltage can be higher than the input voltage or lower than the input voltage. In various embodiments of the present disclosure, the power converter can be bidirectional, being a step-up converter or a step-down converter depending on how the power supply is connected to the converter. In some embodiments, an AC-DC power converter can be constructed from a DC-DC power converter, by, for example, first rectifying the AC input voltage to a DC voltage, and then applying the DC voltage to the DC-DC power converter. It should be understood that permanent magnet hybrid cores can also be used for other forms of AC-DC, DC-AC, and AC-AC power conversion.

[0037] The voltage regulator or power converter may be a switched capacitor power converter. Figure 1A hybrid switched capacitor power converter 100 is shown, which may be, for example, a multi-stage buck power converter. For example, the switched capacitor power converter 100 may include switches M1, M2, M3, M4, M5 and M6 arranged in series connection, flying capacitors C1 and C2, inductors (which may be thin-profile chip inductors with compact size), output capacitors C3, and a control / driver circuit system (not shown) configured to control switches (e.g., turn on or off, etc.). Specifically, each phase branch in the 4-level converter includes 3 units connected in series, wherein each unit includes a complementary switch pair (e.g., switches M1 and M6, switches M2 and M5, and switches M3 and M4) and an associated flying capacitor (e.g., C1 or C2). During circuit operation, a switch in each unit is turned on at a given time. Therefore, the multi-stage power converter circuit 100 may operate in one of eight different states. Depending on the state, the voltage at the inductor node Lx may be at 4 different levels. To efficiently convert voltage, a buck converter may rely on an inductor to store energy while converting it from a higher voltage to a lower voltage.

[0038] As previously discussed, voltage regulators such as switching voltage regulators may rely in part on capacitors and inductors to meet power conversion requirements. However, the inventors herein have recognized that for power electronic devices with large dc currents and high frequency operation, inductors may be affected by disadvantages or current carrying capacity associated with size, conduction or core losses. Although the energy storage density of the inductor can be increased by using a core material with a high saturation flux density, the associated core losses are also increased, making the device inefficient. At higher frequencies (MHz and above) and with increasing dc bias, the core losses may be exaggerated. Although existing inductors may include ferrite cores, which have low core losses at high frequencies, the saturation flux density is also low, limiting the dc performance of the inductor. Therefore, it may be desirable to provide an inductor with a higher saturation flux density, lower core losses, and a high relative permeability to allow a higher current density through the inductor at high frequencies.

[0039] Although currently used ferrites have low saturation flux density, the inventors have recognized that inductor designs do not fully utilize the available saturation flux density range of the core material. Figure 2 The graph 210 shows the saturation behavior of a core material (such as ferrite) on a BH curve or magnetization curve. It should be understood that for illustration purposes only, Figure 2 Hysteresis effects are omitted from the magnetizing curves shown. For dc-based applications, the current and therefore the magnetizing field (H) can be non-negative, indicating that the core can be operated only on the positive side of the BH curve, thereby utilizing only half of the available saturation flux density. However, if the BH curve can be offset, for example by Figure 2The graph 220 of FIG. 220 indicates that by causing reverse saturation to begin at a more positive magnetizing field (H) or current, the core can take advantage of a wider range of saturation flux densities in dc-based applications. Additionally or alternatively, if reverse saturation can be set to begin at H=0 or zero current, the core can use a saturation flux density from -B sat To B sat Certain disclosed embodiments can address these and other challenges.

[0040] In various embodiments of the present disclosure, an inductor design with a permanent magnet hybrid core may be disclosed. In the context of the present disclosure, a "hybrid core" refers to an inductor core comprising a soft magnetic material and a permanent magnetic material. The soft magnetic material may include, but is not limited to, ferrite or powder core material. The permanent magnetic material may include, but is not limited to, neodymium iron boron (NdFeB). The disclosed inductor configuration may provide high peak energy storage, low dc conduction losses, low ac related conduction and core losses. Permanent magnet hybrid core inductors may be desirable in applications including, but not limited to, portable electronic devices (such as tablets, cellular phones, or handheld computers), IoT (Internet of Things) devices, or applications with large dc flux and high frequency flux ripple.

[0041] Some existing inductor designs include permanent magnets to improve the saturation performance of the inductor core. However, for example, the permanent magnets are placed directly in the winding flux path, such as in the gap, or directly in the path of a significant portion of the winding flux, such as adjacent to the gap. Placing the permanent magnets in the winding flux path may result in ac losses in the permanent magnets, which increase with operating frequency, and may demagnetize the permanent magnets at high currents.

[0042] Now refer to Figure 3 , which is a schematic diagram of an exemplary permanent magnet hybrid core according to some embodiments of the present disclosure. Figure 3A perspective view of an exemplary magnetic core 300 is shown, which can include a soft magnetic material 310 and a permanent magnetic material 320, and a coil 330 continuously wound around the core. In some embodiments, the magnetic core 300 can include a first magnetic member, which includes a soft magnetic material 310. The first magnetic member can form a first gap 312 between two end faces of the first magnetic member. The magnetic core can also include a second magnetic member, which includes a permanent magnetic material 320. The second magnetic member can form a second gap 322 between two end faces of the second magnetic member. In some embodiments, the permanent magnetic material 320 can be positioned adjacent to the soft magnetic material 310 so that the permanent magnetic material 320 provides a path for the flow of magnetic flux lines that is at least partially parallel to or substantially parallel to the first magnetic member. In such a configuration, the flow of magnetic flux lines in the permanent magnetic material 320 can be opposite to the flow of magnetic flux lines in the soft magnetic material 310 induced by the current flowing through the coil 330 wound around the soft magnetic material 310, the permanent magnetic material 320, or both. The magnetic flux lines in the permanent magnetic material 320 and the magnetic flux lines in the soft magnetic material 310 are opposite to each other and can cause the BH curve to shift, resulting in higher effective saturation flux, higher peak energy storage and lower conduction losses. In the context of the present disclosure, "opposite flow" of flux lines refers to the flow of magnetic flux lines in opposite directions between two magnetic members. For example, if the magnetic flux lines flow in a clockwise direction in the soft magnetic material, the direction of the magnetic flux lines in the permanent magnetic material can be counterclockwise.

[0043] In some embodiments, the magnetic core 300 may include a first group of magnetic members, a second group of magnetic members, and an electrical conductor (e.g., a coil 330) wound around one or both magnetic members. As used herein, a "magnetic member" refers to an integral or assembled structure of two or more components. For example, an assembled U-shaped magnetic member may include three rectangular pieces that are coupled so that they form a substantially continuous shape with small gaps (if any) in the connection between the pieces. As used herein, a "group" of magnetic members refers to a plurality of magnetic members placed in parallel or in series so that the magnetic members form a single substantially continuous magnetic member.

[0044] In some embodiments, the first gap 312 can be filled with a material having a low electrical conductivity. In some embodiments, the first gap 312 can be filled with a material having a low relative magnetic permeability. In the context of the present disclosure, "relative magnetic permeability" refers to the ratio of the magnetic permeability of a particular medium to the magnetic permeability of free space or a vacuum. In a preferred embodiment, the first gap 312 can be filled with a material having a lower magnetic permeability than the magnetic permeability of the soft magnetic material 310. In some embodiments, the first gap 312 can be filled with a material including, but not limited to, a polymer, a ceramic, or any suitable material having a low electrical conductivity and a low relative magnetic permeability. It should be understood that although Figure 3 An exemplary core design with two gaps is shown, but there may be more gaps corresponding to the number of magnetic members, for example.

[0045] In some embodiments, the second gap 322 can be similar to the first gap 312. The second gap 322 can be filled with a material having low electrical conductivity, low relative magnetic permeability, or both. In some embodiments, the second gap 322 can be filled with a material including, but not limited to, a polymer, a ceramic, or any suitable material having low electrical conductivity and low relative magnetic permeability. In some embodiments, the second gap 322 can be adjacent to the first gap 312, such as Figure 3 However, in practice, the two gaps 322 and 312 may be used as a single gap, such as Figure 4 As shown in the magnetic circuit diagram in (discussed later), there is nothing blocking the flux from the soft magnetic material 310 or the permanent magnetic material 320 from flowing through the gap 312 or 322.

[0046] In some embodiments, the coil 330 may include a spirally wound coil made of a conductive material such as, but not limited to, copper, aluminum, silver, titanium, alloys, or other suitable conductive materials. In a preferred embodiment, the coil 330 may be made of copper. In some embodiments, the coil 330 may be continuously wound around the soft magnetic material 310 or the permanent magnetic material 320 or both.

[0047] like Figure 3 As shown, the permanent magnetic material 320 can be arranged parallel to the soft magnetic material 310 and adjacent to the soft magnetic material 310. In some embodiments, the permanent magnetic material 320 can be placed so that the top surface of the permanent magnetic material 320 is adjacent to the bottom surface of the soft magnetic material 310, and the top surface of the permanent magnetic material 320 is in physical contact with at least a portion of the bottom surface of the soft magnetic material 310 to maintain low magnetic resistance, etc.

[0048] Now refer to Figure 4 , which shows an exemplary magnetic circuit model 400 for the magnetic core 300 according to some embodiments of the present disclosure. As shown in the figure, Figure 3Consistent, the magnetic resistance R of ferrite ferr and the magnetic reluctance R of the permanent magnet PM Model 400 also includes a magnetomotive force (MMF) source N i In the circuit model 400, the magnetic core 300 may have a total core area A c , the soft magnetic material of the core (e.g., ferrite) can be a fraction of F f , and the permanent magnet material can be (1-F f ).although Figure 4 The Norton circuit model of a permanent magnet is shown, but other suitable circuit models may be used. Using the Norton model, the permanent magnet can be modeled as having a magnetic reluctance with a permeability approximately equal to μ0, and a residual flux density B of the permanent magnet. r and cross-sectional area A PM The maximum flux that the permanent magnet portion of the core 300 can carry can be expressed as:

[0049] φ PM =B r A c (1-F f ) Equation 1

[0050] The maximum flux that the ferrite portion of the core 300 can carry can be expressed as:

[0051] φ ferr =B max A c F f Equation 2

[0052] Reference Figure 4 , it can be assumed that the ferrite has a sufficiently large permeability than the permanent magnet so that R ferr < <R PM , and the gap dominates the winding reluctance path, making R ferr < <R gap . From MMF source N i The winding flux can flow mainly through the gap and ferrite, and the permanent magnet flux can flow mainly through the ferrite in the opposite direction, thereby canceling the total dc flux in the ferrite while avoiding the winding flux. It can be assumed that, ideally, essentially all of the permanent magnet flux can return through the ferrite. This is called the ideal model. However, in some embodiments, a portion of the permanent magnet flux can return through the ferrite (discussed later with reference to Figure 5), which is called a modified model.

[0053] Based on the circuit model 400, a first order result of the maximum flux carrying capacity of the magnetic core 300 can be determined. For example, for a fixed core region A in the magnetic core 300 c, can be based on the fractional F of the ferrite used f to adjust the maximum achievable flux. In general, as the fraction of ferrite decreases, and the fraction of permanent magnets increases, more permanent magnet flux is available to oppose the winding flux in the ferrite, thereby increasing the flux carrying capacity of the core 300. This can be expressed mathematically as:

[0054] φ max,hybrid =B max A c F f +B r A c (1-F f ) Equation 3

[0055] Among them, Φ max,hybrid is the maximum flux carried by the hybrid core 300 .

[0056] In some embodiments, in order to improve the saturation characteristics of the hybrid magnetic core (eg, magnetic core 300) using a permanent magnet, the residual flux density B of the permanent magnet is r Can be greater than the saturation flux density B of ferrite max This is because a permanent magnet hybrid core would otherwise make the hybrid design inefficient by exchanging a fraction of the permanent magnet material with poor flux capability characteristics for a fraction of the ferrite. Therefore, based on Equation 3, for large Φ max,hybrid , the fraction of the ferrite area may be small. However, Equation 3 only considers the saturation behavior of the permanent magnet hybrid core at large currents, and does not consider the saturation behavior at small currents, where the permanent magnet flux may reverse saturate the ferrite. In some applications, it may be desirable to prevent reverse saturation at zero current and above. In such cases, the permanent magnet flux may not exceed the maximum flux capability of the ferrite, or Φ PM =B max A c F f However, in order to maximize the flux carrying capacity of the permanent magnet hybrid core, the maximum possible permanent magnet flux may be required. By combining the reverse saturation constraint and the bound of Equation 3, the maximum permanent magnet hybrid core flux can be expressed as:

[0057] φ PM =2B max A c F f Equation 4

[0058] In other words, the flux carrying capacity of the permanent magnet material can be twice that of the flux carrying capacity of the ferrite. In this case, the permanent magnet can shift the BH curve of the ferrite so that Figure 2 The curve diagram 220 shown in FIG. max To +B maxThe full range of saturation flux density can be used in DC based applications.

[0059] Based on Equation 1 and the reverse saturation constraint Φ PM =2B max A c F f To determine the fraction of ferrite area F that will result in the optimum flux carrying capacity of the permanent magnet hybrid core f The optimum ferrite fraction can be expressed as:

[0060]

[0061] Combining Equation 3 and Equation 5, the maximum flux carrying capacity and effective saturation flux density of the permanent magnet hybrid core can be determined based on the material properties and geometry.

[0062]

[0063] A comparison of the maximum achievable flux and effective saturation flux density between a pure ferrite core and a hybrid core (e.g., core 300) based on Equations 6 and 7 indicates that the permanent magnet hybrid core can achieve a greater saturation flux and effective saturation flux density by a factor of For example, if the effective saturation flux density B of a permanent magnet such as neodymium iron boron (NdFeB) is r is 1.2T, and the effective saturation flux density of the ferrite is B max If the saturation flux and effective saturation flux density of the permanent magnet hybrid core are 0.4 T, the saturation flux and effective saturation flux density of the permanent magnet hybrid core may be 0.6 T. In some embodiments, the effective saturation flux density and saturation flux of the permanent magnet hybrid core may be 1.2 times, 1.3 times, 1.4 times, 1.5 times, 1.6 times or more of the effective saturation flux density and saturation flux of the pure ferrite core.

[0064] Now refer to Figure 5A and Figure 5B , which respectively show the simulation data curves of the optimal ferrite fraction and the maximum flux carrying capacity of the permanent magnet hybrid core using the modified model and the ideal model according to the embodiments of the present disclosure. In some embodiments, the fraction k of the permanent magnet flux PM can be returned through the ferrite. For example, if the core has a relatively small gap so that the magnetic resistance R of the ferrite ferr Not significantly less than the magnetic resistance R of the gap gap , then some of the permanent magnet flux can instead pass through the gap. Figure 4 From the perspective of the magnetic circuit model shown, the permanent magnet flux can be split in its return path, with some flux flowing through the ferrite and the rest flowing through the gap. In such a scenario, the maximum achievable flux of the permanent magnet hybrid core can be expressed as:

[0065]

[0066] φ max,hybrid =B max A c F f +k PM B r A c (1-F f ) Equation 9

[0067] In order for the permanent magnet to improve the saturation characteristics of the ferrite core, the effective saturation flux density B of the permanent magnet r Can be greater than the effective saturation flux density B of ferrite max , so that k PM ·B r >B max It should be understood that when k PM →l, the modified model approaches the ideal characteristics discussed previously. Because the less permanent magnet flux cancels the flux in the ferrite, a larger fraction of permanent magnets may be desirable compared to the ideal characteristics. In addition, because the fraction of ferrite area may be smaller, the permanent magnet hybrid core in the modified model may not carry as much external flux compared to the ideal characteristics, as shown in Figure 5B As shown in Figure 500B.

[0068] In some embodiments, the modified model can be used to determine a lower limit on the ferrite fraction for a set of material properties. In a permanent magnet hybrid core, in order for the permanent magnet to continue to do useful work, the minimum k PM Can be B max / B r For the modified model, when K PM →B max / B r When F f,opt The value of →0.5. f <0.5, the ferrite fraction can reverse saturate at zero current. Figure 5A Graph 500A shows the optimum ferrite fraction that does not reverse saturate at zero current. Graph 500A also shows that the modified model approaches the ideal characteristics as the reluctance and gap increase. As expected, as the gap becomes smaller, the modified permanent magnet mixed flux capability approaches the mixed flux capability of the pure ferrite core, and the modified optimum ferrite fraction also approaches the lower limit of 0.5. It should be understood that graph 500B showing the maximum flux carrying capacity of the permanent magnet hybrid core is normalized to the maximum flux carrying capacity of the pure ferrite core.

[0069] For example, a permanent magnet hybrid core such as core 300 can have many advantages over existing designs of ferrite cores and can address one or more of the challenges associated with existing ferrite-based cores in inductors for power conversion applications. A permanent magnet hybrid core can have some or all of the advantages discussed herein.

[0070] i. Greater saturation flux and effective saturation flux density - Permanent magnet hybrid cores have greater flux carrying capacity because the permanent magnet flux can oppose the total dc winding flux in the ferrite, offsetting the BH curve to improve saturation performance while avoiding winding flux in the permanent magnet to avoid demagnetization. High energy storage capacity and low conduction losses can be associated with higher saturation flux and effective saturation flux density.

[0071] ii. Enhanced energy storage - For fixed dc resistance and inductance, the energy storage of the inductor can be determined by the saturation current, which depends on the maximum achievable flux. Compared with pure ferrite cores, permanent magnet hybrid cores can have greater energy storage, with a factor of:

[0072]

[0073] For example, if B r =1.2T and B max =0.4T, then under fixed dc resistance and inductance, the permanent magnet hybrid core can achieve 2.25 times higher energy storage than the ferrite core, as determined based on Equation 10.

[0074] In some embodiments, at fixed dc losses, permanent magnet hybrid cores can achieve 1.5 times higher maximum energy storage compared to ferrite cores. In dc-based applications, fixed dc losses can be substantially similar to total losses and can also be a good approximation for fixed temperature rise constraints.

[0075] iii. Lower DC resistance - The dc resistance of the core can be determined based on the total winding area, winding filling factor, average length turns and number of turns, etc. For a comparison of a ferrite core and a permanent magnet hybrid core with similar winding area, similar winding filling factor, and similar average length turns, the permanent magnet hybrid core can have a lower dc resistance by a factor of:

[0076]

[0077] Where N = number of turns, ρ Cu = resistivity of copper, l = average length of turns, A w = total winding area, and K u =Winding filling factor.

[0078] For example, if Br =1.2T and B max =0.4T, then at fixed energy storage and inductance, the permanent magnet hybrid core can achieve a dc resistance 0.44 times lower than the ferrite core, or a 56% reduction, as determined based on Equation 11.

[0079] iv. Design Flexibility - The ac flux may flow primarily in some subset of the soft magnetic material in the core, rather than in the permanent magnetic material. Therefore, for the portions of the hybrid core exposed to the ac flux, such as the soft magnets, materials suitable for low core losses at the desired operating frequency can be selected, allowing design and material flexibility. The permanent magnets can have multiple potential locations in the core, providing further flexibility in inductor design considerations.

[0080] In some embodiments, while adding permanent magnets to ferrites can improve the saturation performance of the core, the core losses may be higher due at least to the smaller fraction of available ferrite used to carry the ac flux. However, since the permanent magnet hybrid core is intended for dc-dominated applications, the increase in core losses has a negligible effect, if any, on the total losses.

[0081] It should be understood that although the magnetic core 300 is discussed and shown as being used in an inductor having a single winding, it can also be used in a transformer or coupled inductor having multiple windings. Additionally or alternatively, the magnetic core 300 can be designed to have multiple flux paths for dc flux and / or ac flux. It should be understood that different core geometries and permanent magnet positions can be appropriately implemented.

[0082] Now refer to Fig. 6A , which shows a schematic diagram of an exemplary magnetic core 600 according to an embodiment of the present disclosure. The magnetic core 600 may include a double U-shaped magnetic core geometry, wherein the magnetic core is divided into two symmetrical U-shaped halves 602 and 604 along an axis of symmetry 601. As shown, the magnetic core 600 may include a permanent magnet hybrid core, which includes a soft magnetic material and a permanent magnetic material. In some embodiments, the U-shaped halves 602 and 604 may be oriented so that they are separated by two gaps along the axis of symmetry 601. In some embodiments, one or both of the halves 602 and 604 may be made of a single piece or a plurality of pieces assembled together to form a substantially continuous piece with negligible space between them. In some embodiments, the cross-sections of the U-shaped halves 602 and 604 may be uniform or non-uniform, or vary uniformly or non-uniformly along their lengths. For example, the end faces may have a larger cross-section, while the middle portion may have a narrower cross-section. Although not shown, it should be understood that other implementations, cross-sections, geometries, or combinations thereof are also possible.

[0083] In some embodiments, the ratio of the minimum cross-sectional area of ​​the first group of magnetic members to the sum of the minimum cross-sectional area of ​​the first group of magnetic members and the minimum cross-sectional area of ​​the second group of magnetic members is greater than 0.5, greater than 0.6, greater than 0.7, greater than 0.8, greater than 0.9, or greater than 0.95. The first group of magnetic members may include soft magnetic material members, and the second group of magnetic members may include permanent magnetic material members.

[0084] FIG. 6B to FIG. 6J is a schematic diagram of an exemplary implementation of a permanent magnet hybrid core in a parallel configuration according to an embodiment of the present disclosure. As used herein, a "parallel implementation" or "parallel configuration" refers to the position of the permanent magnet with reference to the position of the ferrite. In a parallel implementation, the permanent magnetic material can be positioned adjacent to the inner surface or the outer surface of the soft magnetic material or both. In some parallel implementations, the permanent magnet can be enclosed in or sandwiched in the soft magnetic material, or the soft magnetic material can be sandwiched or enclosed in the permanent magnetic material. In some embodiments, the permanent magnetic material can follow the soft magnetic material along a portion of its length.

[0085] Figure 6B A U-shaped half 600B of the magnetic core 600 is shown, which includes a permanent magnetic material parallel to and adjacent to the soft magnetic material, such that the permanent magnetic material abuts the soft magnetic material. In such a configuration, the total length of the soft magnetic material can be approximately similar or approximately the same as the total length of the permanent magnetic material. The implementation represented by 600B can be similar to Figure 3 The magnetic core is 300. Figure 6C A U-shaped half 600C of the magnetic core 600 is shown, which includes a permanent magnetic material surrounding a soft magnetic material on an outer surface such that the total length of the permanent magnetic material is greater than the total length of the soft magnetic material. Fig.6D A U-shaped half 600D of the magnetic core 600 is shown, which includes a permanent magnetic material surrounded by a soft magnetic material such that the total length of the soft magnetic material is greater than the total length of the permanent magnetic material.

[0086] In some embodiments, the magnetic core 600 or a half of the magnetic core 600 may include a third magnetic member including a soft magnetic material. The second magnetic member may be located between the first magnetic member and the third magnetic member. The second magnetic member may form a gap between two end faces of the second magnetic member, and the third magnetic member may form a third gap between two end faces of the third magnetic member, and the second gap and the third gap may be adjacent to the first gap. Fig. 6E and Fig. 6F U-shaped halves 600E and 600F of the magnetic core 600 are shown respectively, comprising permanent magnetic material sandwiched between two pieces of soft magnetic material. Figure 6GA U-shaped half 600G of the magnetic core 600 is shown, which comprises a permanent magnetic material member enclosed within a soft magnetic material, such that the permanent magnetic material member is surrounded on all sides by the soft magnetic material.

[0087] In some embodiments, the ratio of the sum of the minimum cross-sectional area of ​​the first group of components and the minimum cross-sectional area of ​​the third group of components to the sum of the minimum cross-sectional area of ​​the first group of components, the minimum cross-sectional area of ​​the third group of components, and the minimum cross-sectional area of ​​the second group of components is greater than 0.5, greater than 0.6, greater than 0.7, greater than 0.8, greater than 0.9, or greater than 0.95. The first group of magnetic components and the third group of magnetic components may include soft magnetic material components, and the second group of magnetic components may include permanent magnetic material components.

[0088] In some embodiments, the magnetic core 600 or a half of the magnetic core 600 may include a third magnetic member, the third magnetic member including a permanent magnetic material. The second magnetic member may be located between the first magnetic member and the third magnetic member. The second magnetic member may form a gap between two end faces of the second magnetic member, and the third magnetic member may form a third gap between two end faces of the third magnetic member, and the second gap and the third gap may be adjacent to the first gap. Figure 6H 61 show U-shaped halves 600H and 600I of the magnetic core 600, respectively, which include a soft magnetic material member sandwiched between two permanent magnetic material members.

[0089] Figure 6J A U-shaped half 600J of the magnetic core 600 is shown, which includes a soft magnetic material enclosed within a permanent magnetic material such that the soft magnetic material is surrounded by the permanent magnetic material on all sides. FIG. 6B to FIG. 6J Various parallel implementations of a dual U-shaped core geometry are shown, but other implementations not shown are possible. It should also be understood that other geometries such as, but not limited to, a pot core geometry may also be used.

[0090] Now refer to Figure 7 , which shows an exemplary non-parallel implementation of a half core 700 of a double U-shaped inductor core according to some embodiments of the present disclosure. The half core 700 may include a permanent magnetic material member 720 positioned partially along the inner surface of the soft magnetic material member 710. In some embodiments, the permanent magnet hybrid core may appropriately include a combination of parallel, partially parallel, or non-parallel implementations. It should be understood that the location of the permanent magnetic material partially along the inner surface is merely exemplary and non-limiting, and other implementations are possible. For example, in FIG. 6B to FIG. 6J In the implementation shown, the permanent magnets may be positioned along only a portion of the length of the soft magnetic body.

[0091] Now refer to Fig. 8A, which shows a perspective view of an exemplary permanent magnet hybrid core inductor 800 according to some embodiments of the present disclosure. The inductor 800 can include a pot core geometry. Figure 8B is a schematic diagram of a cross-sectional view of an inductor 800 taken along AA' according to some embodiments of the present disclosure. The inductor 800 may include a soft magnet 810, a winding or coil 830 wound around the soft magnet 810, a permanent magnet 820 placed at the center of a pot-shaped core, a flux guide plate 840, and a shield 850.

[0092] The inductor 800 may include a permanent magnet hybrid core inductor. In some embodiments, the inductor 800 may include a permanent magnet 820 placed in the center of a pot-shaped core. The inductor 800 may also include a flux guide plate 840 on at least one end surface such as the top surface or the bottom surface of the inductor 800. In a preferred embodiment, as shown in FIG. Figure 8B As shown, flux guide plates 840 can be placed on the top and bottom surfaces of the inductor 800. The flux guide plates 840 can guide flux radially outward from the permanent magnet 810. In some embodiments, the flux guide plates 840 can be made of a soft magnetic material with high magnetic permeability and high saturation flux density. In some embodiments, the flux guide plates 840 can also be conductive. In a preferred embodiment, the flux guide plates 840 can be made of a material such as but not limited to steel. Gaps can be located in the housing to encourage flux to return from the flux guide plates 840 through the top and bottom of the soft magnet 810.

[0093] In some embodiments, the inductor 800 may further include a shield 850 made of a conductive material, including but not limited to copper, aluminum, silver, and other conductive materials. The shield 850 may be located between the soft magnetic body 810 and the flux guide plate 840 to guide the dc flux path. In some embodiments, the flux guide plate 840 may be affected by high losses including hysteresis losses and eddy current losses when subjected to a high frequency field. In some embodiments, although the shield 850 can reduce losses by, for example, blocking or reducing the ac winding flux entering the flux guide plate 840, it can allow dc flux to flow between the flux guide plate 840 and the soft magnetic body 810. In some embodiments, the shield 850 may include an edge portion having a first thickness and a center portion having a second thickness different from the first thickness. However, in some embodiments, the edge of the shield 850 may be thinner than the rest of the shield 850. The thicker outer edge can reduce eddy current losses in the shield 850. In some embodiments, the shield 850 may be made of a single continuous conductive material piece or of a plurality of conductive material pieces.

[0094] Now refer to Fig. 9, which shows the winding and permanent magnet flux paths in the inductor 800 of FIG. 8 according to an embodiment of the present disclosure. Configuration 910 shows the permanent magnet magnetic flux path in the axisymmetric cross section of the inductor 800. In configuration 910, the flux lines of the permanent magnet 820 can be radially guided outward by the flux guide plate 840 and returned toward the soft magnet 810, thereby guiding the flux lines through the top plate of the pot-shaped core of the inductor 800 and through its center column. Configuration 920 shows that the dc winding flux flows in the soft magnet 810 and flows through the external gap between the two end faces of the soft magnet 810 without the influence of the PM (for example, the PM is replaced by a non-magnetic material). Configuration 930 shows the combination of the permanent magnet flux lines and the dc winding flux lines in the inductor 800.

[0095] Now refer to Fig.10 , which shows a comparison of simulated and experimental saturation behavior data between a permanent magnet hybrid core inductor and a pure ferrite core inductor according to some embodiments of the present disclosure. The simulation was performed using ANSYS Maxwell software with a 2D cylindrical finite element analysis (FEA) method. Fig.10 As shown, for an allowable 30% inductance drop, the permanent magnet hybrid core inductor prototype achieves a simulated 11.1A and an experimental 10.0A dc current. This difference can be explained by the physical implementation of an off-the-shelf permanent magnet, which includes a stack of permanent magnets each coated with a nickel coating. The coating can introduce a gap between the permanent magnet and the flux guide plate 840, and can also provide a magnetic shunt path for the permanent magnet flux, thereby reducing the amount of permanent magnet flux in the soft magnet 810 that opposes the dc winding flux.

[0096] Based on simulation data and experimental data, the permanent magnet hybrid core inductor outperforms the pure ferrite inductor. For example, for an allowable 30% inductance drop, in the simulation, the permanent magnet hybrid core inductor achieves a 34% reduction in dc resistance and a 37% increase in energy storage with a 17% increase in maximum dc current. The experimental results are consistent with the simulation results.

[0097] Fig.11 A data graph showing the frequency response of the inductance of a pure ferrite core inductor compared to a permanent magnet hybrid core inductor. As shown, the ferrite and permanent magnet hybrid core inductors exhibit substantially similar inductance frequency responses. For example, at 1 MHz, the inductance of both the ferrite core inductor and the permanent magnet hybrid core inductor is 35.1 μH.

[0098] It should be understood that, for the sake of clarity, certain features of this specification described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of brevity, various features of this specification described in the context of a single embodiment may also be provided individually or in any suitable subcombination or in any other described embodiment of this specification as appropriate. Certain features described in the context of various embodiments are not considered essential features of those embodiments unless the embodiment is inoperative without those elements.

[0099] The following terms may be used to further describe the embodiments:

[0100] 1. A magnetic core, comprising:

[0101] a first group of components, the first group of components comprising a soft magnetic material, the first group of components forming a first gap between two end surfaces of the first group of components; and

[0102] a second set of components comprising a permanent magnetic material and positioned adjacent to the first set of components;

[0103] The second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

[0104] 2. A magnetic core according to clause 1, wherein the first set of components includes a soft magnetic component.

[0105] 3. The magnetic core according to clause 1, wherein the first set of members includes two soft magnetic members, each soft magnetic member having a U-shape and providing one of the two end faces of the first set of members.

[0106] 4. A magnetic core according to claim 1, wherein the first set of components and the second set of components are configured so that the flow of magnetic flux lines in the second set of components is opposite to the flow of magnetic flux lines in the first set of components induced by current flowing through an electrical conductor wrapped around at least the first set of components.

[0107] 5. A magnetic core according to claim 4, wherein the first set of components and the second set of components are configured so that the flow of magnetic flux lines in the second set of components is opposite to the flow of magnetic flux lines in the first set of components induced by current flowing through an electrical conductor wound around the first set of components and the second set of components.

[0108] 6. A magnetic core according to claim 1, wherein the first set of components and the second set of components are configured so that the flow of magnetic flux lines through the first set of components induced by current flowing through an electrical conductor wrapped around at least the first set of components is at least 50 times the flow of magnetic flux lines through the second set of components, as determined by finite element modeling.

[0109] 7. The magnetic core according to clause 1, wherein the second set of members provides a path for magnetic flux lines to flow between two end surfaces of the first set of members that is at least partially parallel to the first set of members.

[0110] 8. The magnetic core of clause 1, wherein the second set of members provides a path for the flow of magnetic flux lines that is substantially completely parallel to the first set of members.

[0111] 9. The magnetic core according to clause 1, wherein the soft magnetic material is ferrite.

[0112] 10. The magnetic core according to clause 1, wherein the soft magnetic material is a powder core material.

[0113] 11. The magnetic core of clause 1, wherein the first gap is filled with air.

[0114] 12. The magnetic core of clause 1, wherein the first air gap is filled with a material having a lower magnetic permeability than the magnetic permeability of the first set of members.

[0115] 13. The magnetic core of clause 1, wherein at least one member of the second set of members abuts at least one member of the first set of members.

[0116] 14. The magnetic core according to clause 1, wherein the second set of members forms a second gap between two end surfaces of the second set of members, the second gap being adjacent to the first gap.

[0117] 15. A magnetic core according to clause 14, wherein the second set of members comprises two permanent magnetic members, each permanent magnetic member having a U-shape and providing one of the two end faces of the second set of members.

[0118] 16. The magnetic core of clause 1, wherein a total length of the second set of members is substantially the same as a total length of the first set of members.

[0119] 17. The magnetic core of clause 1, wherein a total length of the second set of members is less than a total length of the first set of members.

[0120] 18. The magnetic core of clause 1, wherein a total length of the second set of members is greater than a total length of the first set of members.

[0121] 19. The magnetic core of clause 1, wherein at least one member of the second set of members is positioned adjacent an outer surface of at least one member of the first set of members.

[0122] 20. The magnetic core of clause 1, wherein at least one member of the second set of members is positioned adjacent to an inner surface of at least one member of the first set of members.

[0123] 21. The magnetic core of clause 1, wherein at least one member of the second set of members is located in a hollow space provided by at least one member of the first set of members.

[0124] 22. The magnetic core of clause 1, wherein at least one member of the first set of members is located in a hollow space provided by at least one member of the second set of members.

[0125] 23. The magnetic core of clause 1, wherein a ratio of a minimum cross-sectional area of ​​the first set of members to a sum of a minimum cross-sectional area of ​​the first set of members and a minimum cross-sectional area of ​​the second set of members is greater than 0.5.

[0126] 24. A magnetic core according to clause 23, wherein the ratio is greater than 0.6.

[0127] 25. A magnetic core according to clause 24, wherein the ratio is greater than 0.7.

[0128] 26. A magnetic core according to clause 25, wherein the ratio is greater than 0.8.

[0129] 27. A magnetic core according to clause 26, wherein the ratio is greater than 0.9.

[0130] 28. A magnetic core according to clause 27, wherein the ratio is greater than 0.95.

[0131] 29. The magnetic core of clause 1, further comprising a third set of components comprising a soft magnetic material, wherein the second set of components is located between the first set of components and the third set of components.

[0132] 30. A magnetic core according to clause 29, wherein the second group of components forms a second gap between two end surfaces of the second group of components, wherein the third group of components forms a third gap between two end surfaces of the third group of components, and wherein both the second gap and the third gap are adjacent to the first gap.

[0133] 31. A magnetic core according to clause 29, wherein the ratio of the sum of the minimum cross-sectional area of ​​the first group of components and the minimum cross-sectional area of ​​the third group of components to the sum of the minimum cross-sectional area of ​​the first group of components, the minimum cross-sectional area of ​​the third group of components and the minimum cross-sectional area of ​​the second group of components is greater than 0.5.

[0134] 32. A magnetic core according to clause 31, wherein the ratio is greater than 0.6.

[0135] 33. A magnetic core according to clause 32, wherein the ratio is greater than 0.7.

[0136] 34. A magnetic core according to clause 33, wherein the ratio is greater than 0.8.

[0137] 35. A magnetic core according to clause 34, wherein the ratio is greater than 0.9.

[0138] 36. A magnetic core according to clause 35, wherein the ratio is greater than 0.95.

[0139] 37. The magnetic core of clause 1, further comprising a third set of components comprising permanent magnetic material, wherein the first set of components is located between the second set of components and the third set of components.

[0140] 38. A magnetic core according to clause 37, wherein the second group of components forms a second gap between two end surfaces of the second group of components, wherein the third group of components forms a third gap between two end surfaces of the third group of components, and wherein both the second gap and the third gap are adjacent to the first gap.

[0141] 39. A magnetic core according to clause 37, wherein the ratio of the sum of the minimum cross-sectional areas of the first set of components to the sum of the minimum cross-sectional areas of the first set of components, the minimum cross-sectional areas of the second set of components, and the minimum cross-sectional areas of the third set of components is greater than 0.5.

[0142] 40. The magnetic core of clause 39, wherein the ratio is greater than 0.6.

[0143] 41. A magnetic core according to clause 40, wherein the ratio is greater than 0.7.

[0144] 42. A magnetic core according to clause 41, wherein the ratio is greater than 0.8.

[0145] 43. A magnetic core according to clause 42, wherein the ratio is greater than 0.9.

[0146] 44. A magnetic core according to clause 43, wherein the ratio is greater than 0.95.

[0147] 45. The magnetic core of clause 1, wherein the first set of components comprises a plurality of soft magnetic materials.

[0148] 46. ​​The magnetic core of clause 1, further comprising another soft magnetic member having a higher saturation flux density than the first set of members, the other soft magnetic member being configured to guide magnetic flux flowing through at least one of the first set of members and the second set of members.

[0149] 47. The magnetic core of clause 46, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members.

[0150] 48. The magnetic core according to clause 29 further includes another soft magnetic component having a higher saturation flux density than the first group of components and the third group of components, and the other soft magnetic component is configured to guide the magnetic flux flowing through at least one of the first group of components, the second group of components and the third group of components.

[0151] 49. The magnetic core of clause 48, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members or at least one member of the third set of members.

[0152] 50. The magnetic core of clause 37, further comprising another soft magnetic member having a higher saturation flux density than the first set of members, the other soft magnetic member being configured to guide magnetic flux flowing through at least one of the first set of members, the second set of members, and the third set of members.

[0153] 51. The magnetic core of clause 50, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members.

[0154] 52. The magnetic core of clause 47, wherein the conductive shield comprises an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

[0155] 53. The magnetic core of clause 49, wherein the conductive shield comprises an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

[0156] 54. The magnetic core of clause 51, wherein the conductive shield comprises an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

[0157] 55. A magnetic core, comprising:

[0158] A permanent magnet having a curved surface; and

[0159] a soft magnetic member positioned adjacent to the curved surface of the permanent magnet;

[0160] The soft magnetic member forms a first gap between two end surfaces of the soft magnetic member.

[0161] wherein the soft magnetic member provides a hollow space for winding an electrical conductor around the permanent magnet, and

[0162] The permanent magnet provides a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic component.

[0163] 56. A magnetic core according to clause 55, wherein the flow of magnetic flux lines in the permanent magnet is opposite to the flow of magnetic flux lines in the soft magnetic member induced by the current flowing through the electrical conductor.

[0164] 57. A magnetic core according to clause 55, wherein the soft magnetic member and the permanent magnet are configured so that the flow of magnetic flux lines through the soft magnetic member induced by the current flowing through the electrical conductor is at least 50 times the flow of magnetic flux lines through the permanent magnet, as determined by finite element modeling.

[0165] 58. The magnetic core according to clause 55, wherein the permanent magnet provides a path at least partially parallel to the soft magnetic member for the flow of magnetic flux lines between the two end faces of the soft magnetic member.

[0166] 59. A magnetic core according to clause 55, wherein the permanent magnet provides a path for the flow of magnetic flux lines that is substantially completely parallel to the soft magnetic member.

[0167] 60. The magnetic core of clause 55, wherein the soft magnetic material is ferrite.

[0168] 61. A magnetic core according to clause 55, wherein the soft magnetic material is a powder core material.

[0169] 62. The magnetic core of clause 55, wherein the first gap is filled with air.

[0170] 63. The magnetic core of clause 55, wherein the first air gap is filled with a material having a lower magnetic permeability than the soft magnetic member.

[0171] 64. The magnetic core of clause 55, wherein at least a portion of the soft magnetic member abuts at least a portion of the permanent magnet.

[0172] 65. A magnetic core according to clause 64, wherein the soft magnetic member is adjacent to a curved surface of the permanent magnet.

[0173] 66. A magnetic core according to clause 55, wherein the soft magnetic member is configured so that the electrical conductor is also wrapped around a portion of the soft magnetic member.

[0174] 67. The magnetic core of clause 55, further comprising a second soft magnetic member configured to direct magnetic flux from the permanent magnet to the soft magnetic member.

[0175] 68. The magnetic core of clause 67, further comprising a conductive shield positioned adjacent to the second soft magnetic member and the soft magnetic member.

[0176] 69. The magnetic core of clause 68, wherein the conductive shield comprises an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

[0177] 70. An inductor comprising:

[0178] An electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of clauses 1 to 69.

[0179] 71. An apparatus comprising:

[0180] A switching voltage regulator comprising an inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of clauses 1 to 69.

[0181] 72. The apparatus of clause 71, wherein the switching frequency of the switching voltage regulator is at least 1 MHz.

[0182] 73. An apparatus comprising:

[0183] A power conversion circuit, comprising an inductor, the inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

[0184] 74. An apparatus comprising:

[0185] A power conversion circuit, the power conversion circuit comprising a switched capacitor circuit and a switching regulator, the switching regulator comprising an inductor, the inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

[0186] 75. The apparatus of claim 74, wherein the switching frequency of the switching regulator is at least 1 MHz.

[0187] The foregoing summarizes the features of several embodiments so that those skilled in the art can better understand aspects of the present disclosure. Those skilled in the art will appreciate that they can easily use the present disclosure as a basis for designing or modifying other processes and structures to perform the same purposes and / or achieve the same advantages as the embodiments described herein. Those skilled in the art will also appreciate that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they can make various changes, substitutions, and modifications herein without departing from the spirit and scope of the present disclosure.

Claims

1. A magnetic core, comprising: A first group of components, the first group of components comprising a soft magnetic material, the first group of components forming a first gap between two end surfaces of the first group of components; as well as a second set of components comprising a permanent magnetic material and positioned adjacent to the first set of components; The second set of components provides a path for the flow of magnetic flux lines that is at least partially parallel to the first set of components.

2. The magnetic core according to claim 1, wherein: The first set of components includes a soft magnetic component.

3. The magnetic core according to claim 1, wherein: The first set of members includes two soft magnetic members, each of which has a U-shape and provides one of the two end surfaces of the first set of members.

4. The magnetic core according to claim 1, wherein: The first and second sets of components are configured such that flow of magnetic flux lines in the second set of components is opposite to flow of magnetic flux lines in the first set of components induced by current flowing through an electrical conductor wrapped around at least the first set of components.

5. The magnetic core according to claim 4, wherein: The first and second sets of components are configured such that flow of magnetic flux lines in the second set of components is opposite to flow of magnetic flux lines in the first set of components induced by current flowing through electrical conductors wrapped around the first and second sets of components.

6. The magnetic core according to claim 1, wherein: The first and second sets of components are configured such that a flow of magnetic flux lines through the first set of components induced by current flowing through an electrical conductor wrapped around at least the first set of components is at least 50 times greater than a flow of magnetic flux lines through the second set of components, as determined by finite element modeling.

7. The magnetic core according to claim 1, wherein: The second set of components provides a path at least partially parallel to the first set of components for magnetic flux lines to flow between two end surfaces of the first set of components.

8. The magnetic core according to claim 1, wherein The second set of members provides a path for the flow of magnetic flux lines that is substantially completely parallel to the first set of members.

9. The magnetic core according to any one of claims 1 to 8, wherein: The soft magnetic material is ferrite.

10. The magnetic core according to any one of claims 1 to 8, wherein: The soft magnetic material is a powder core material.

11. The magnetic core according to any one of claims 1 to 10, wherein: The first gap is filled with air.

12. The magnetic core according to any one of claims 1 to 10, wherein: The first air gap is filled with a material having a lower magnetic permeability than the first set of components.

13. The magnetic core according to any one of claims 1 to 12, wherein: At least one member of the second set of members abuts at least one member of the first set of members.

14. The magnetic core according to any one of claims 1 to 13, wherein: The second group of components forms a second gap between two end surfaces of the second group of components, and the second gap is adjacent to the first gap.

15. The magnetic core according to claim 14, wherein: The second set of members includes two permanent magnetic members, each of which has a U-shape and provides one of the two end faces of the second set of members.

16. The magnetic core according to any one of claims 1 to 15, wherein: The total length of the second set of components is substantially the same as the total length of the first set of components.

17. The magnetic core according to any one of claims 1 to 15, wherein: The total length of the second set of components is less than the total length of the first set of components.

18. The magnetic core according to any one of claims 1 to 15, wherein: The total length of the second set of components is greater than the total length of the first set of components.

19. The magnetic core according to any one of claims 1 to 18, wherein: At least one member of the second set of members is positioned adjacent to an outer surface of at least one member of the first set of members.

20. The magnetic core according to any one of claims 1 to 18, wherein: At least one member of the second set of members is positioned adjacent to an inner surface of at least one member of the first set of members.

21. The magnetic core according to any one of claims 1 to 18, wherein: At least one member of the second set of members is located in a hollow space provided by at least one member of the first set of members.

22. The magnetic core according to any one of claims 1 to 18, wherein: At least one member of the first set of members is located in a hollow space provided by at least one member of the second set of members.

23. The magnetic core according to any one of claims 1 to 22, wherein: A ratio of a minimum cross-sectional area of ​​the first set of components to a sum of a minimum cross-sectional area of ​​the first set of components and a minimum cross-sectional area of ​​the second set of components is greater than 0.

5.

24. The magnetic core according to claim 23, wherein: The ratio is greater than 0.

6.

25. The magnetic core according to claim 24, wherein The ratio is greater than 0.

7.

26. The magnetic core according to claim 25, wherein The ratio is greater than 0.

8.

27. The magnetic core according to claim 26, wherein: The ratio is greater than 0.

9.

28. The magnetic core according to claim 27, wherein The ratio is greater than 0.

95.

29. The magnetic core according to any one of claims 1 to 28, further comprising a third group of components, the third group of components comprising a soft magnetic material, wherein: The second group of components is located between the first group of components and the third group of components.

30. The magnetic core according to claim 29, wherein The second group of components forms a second gap between two end surfaces of the second group of components, wherein the third group of components forms a third gap between two end surfaces of the third group of components, and wherein both the second gap and the third gap are adjacent to the first gap.

31. The magnetic core according to claim 29 or 30, wherein: The ratio of the sum of the minimum cross-sectional area of ​​the first group of components and the minimum cross-sectional area of ​​the third group of components to the sum of the minimum cross-sectional area of ​​the first group of components, the minimum cross-sectional area of ​​the third group of components and the minimum cross-sectional area of ​​the second group of components is greater than 0.

5.

32. The magnetic core according to claim 31, wherein The ratio is greater than 0.

6.

33. The magnetic core according to claim 32, wherein: The ratio is greater than 0.

7.

34. The magnetic core according to claim 33, wherein The ratio is greater than 0.

8.

35. The magnetic core according to claim 34, wherein The ratio is greater than 0.

9.

36. The magnetic core according to claim 35, wherein The ratio is greater than 0.

95.

37. A magnetic core according to any one of claims 1 to 28, further comprising a third set of components, the third set of components comprising permanent magnetic material, wherein: The first group of components is located between the second group of components and the third group of components.

38. The magnetic core according to claim 37, wherein The second group of components forms a second gap between two end surfaces of the second group of components, wherein the third group of components forms a third gap between two end surfaces of the third group of components, and wherein both the second gap and the third gap are adjacent to the first gap.

39. The magnetic core according to claim 37 or 38, wherein: A ratio of the sum of the minimum cross-sectional areas of the first group of components to the sum of the minimum cross-sectional areas of the first group of components, the minimum cross-sectional areas of the second group of components, and the minimum cross-sectional areas of the third group of components is greater than 0.

5.

40. The magnetic core according to claim 39, wherein The ratio is greater than 0.

6.

41. The magnetic core according to claim 40, wherein The ratio is greater than 0.

7.

42. The magnetic core according to claim 41, wherein The ratio is greater than 0.

8.

43. The magnetic core according to claim 42, wherein The ratio is greater than 0.

9.

44. The magnetic core according to claim 43, wherein The ratio is greater than 0.

95.

45. A magnetic core according to any one of claims 1 or 3 to 44, wherein The first set of components includes a plurality of soft magnetic materials.

46. ​​The magnetic core according to any one of claims 1 to 45, further comprising another soft magnetic member having a higher saturation flux density than the first set of members, the other soft magnetic member being configured to guide magnetic flux flowing through at least one of the first set of members and the second set of members.

47. The magnetic core of claim 46, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members.

48. The magnetic core according to any one of claims 29 to 36 further includes another soft magnetic component having a higher saturation flux density than the first group of components and the third group of components, and the other soft magnetic component is configured to guide the magnetic flux flowing through at least one of the first group of components, the second group of components and the third group of components.

49. The magnetic core of claim 48, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members or at least one member of the third set of members.

50. The magnetic core according to any one of claims 37 to 44 further comprises another soft magnetic component having a higher saturation flux density than the first group of components, wherein the other soft magnetic component is configured to guide magnetic flux flowing through at least one of the first group of components, the second group of components and the third group of components.

51. The magnetic core of claim 50, further comprising a conductive shield positioned adjacent to the other soft magnetic member and to at least one member of the first set of members.

52. A magnetic core according to any one of claims 47 or 49, wherein The conductive shield includes an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

53. The magnetic core of claim 49, wherein: The conductive shield includes an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

54. The magnetic core of claim 51, wherein: The conductive shield includes an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

55. A magnetic core, comprising: A permanent magnet having a curved surface; as well as a soft magnetic member positioned adjacent to the curved surface of the permanent magnet; The soft magnetic member forms a first gap between two end surfaces of the soft magnetic member. wherein the soft magnetic member provides a hollow space for winding an electrical conductor around the permanent magnet, and The permanent magnet provides a path for the flow of magnetic flux lines that is at least partially parallel to the soft magnetic component.

56. The magnetic core according to claim 55, wherein The flow of magnetic flux lines in the permanent magnet is opposite to the flow of magnetic flux lines in the soft magnetic member induced by the current flowing through the electrical conductor.

57. The magnetic core of claim 55, wherein: The soft magnetic member and the permanent magnet are configured such that the flow of magnetic flux lines through the soft magnetic member induced by current flowing through the electrical conductor is at least 50 times the flow of magnetic flux lines through the permanent magnet, as determined by finite element modeling.

58. The magnetic core of claim 55, wherein: The permanent magnet provides a path at least partially parallel to the soft magnetic member for the flow of magnetic flux lines between the two end faces of the soft magnetic member.

59. The magnetic core of claim 55, wherein: The permanent magnets provide a path for the flow of magnetic flux lines that is substantially completely parallel to the soft magnetic member.

60. A magnetic core according to any one of claims 55 to 59, wherein The soft magnetic material is ferrite.

61. A magnetic core according to any one of claims 55 to 59, wherein The soft magnetic material is a powder core material.

62. A magnetic core according to any one of claims 55 to 61, wherein The first gap is filled with air.

63. A magnetic core according to any one of claims 55 to 61, wherein The first air gap is filled with a material having a magnetic permeability lower than that of the soft magnetic member.

64. A magnetic core according to any one of claims 55 to 63, wherein At least a portion of the soft magnetic member abuts at least a portion of the permanent magnet.

65. The magnetic core of claim 64, wherein: The soft magnetic member abuts against the curved surface of the permanent magnet.

66. A magnetic core according to any one of claims 55 to 65, wherein The soft magnetic member is configured such that the electrical conductor is also wound around a portion of the soft magnetic member.

67. The magnetic core of any one of claims 55 to 66, further comprising a second soft magnetic member configured to direct magnetic flux from the permanent magnet to the soft magnetic member.

68. The magnetic core of claim 67, further comprising a conductive shield positioned adjacent to the second soft magnetic member and the soft magnetic member.

69. The magnetic core of claim 68, wherein The conductive shield includes an edge portion having a first thickness and a center portion having a second thickness different from the first thickness.

70. An inductor comprising: An electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

71. An apparatus comprising: A switching voltage regulator, comprising an inductor, the inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

72. The apparatus of claim 71, wherein: The switching frequency of the switching voltage regulator is at least 1 MHz.

73. An apparatus comprising: A power conversion circuit, comprising an inductor, the inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

74. An apparatus comprising: A power conversion circuit, the power conversion circuit comprising a switched capacitor circuit and a switching regulator, the switching regulator comprising an inductor, the inductor comprising an electrical conductor wound around a magnetic core, wherein the magnetic core is according to any one of claims 1 to 69.

75. The apparatus of claim 74, wherein: The switching frequency of the switching regulator is at least 1 MHz.

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