Flux-formed inductor structure for reduced high-frequency losses

Abstract

A flux-formed inductor structure for reducing high-frequency losses is proposed. The inductor structure may include an upper core, a lower core, and one or more central posts disposed between the upper and lower cores. The inductor structure may also include a winding, at least a portion of which is disposed between the upper and lower cores. The upper core may include at least one upper flux-formed plate vertically overlapping at least a portion of the winding.

Description

[Technical Field]

[0001] [CROSS-REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Provisional Patent Application No. 63 / 483,434, filed February 6, 2023, entitled "FLUX SHAPING INDUCTOR STRUCTURES FOR REDUCED HIGH-FREQUENCY LOSSES," the disclosure of which is incorporated herein by reference in its entirety.

[0002] The present disclosure relates to flux-formed inductor structures for reducing high frequency losses. [Background technology]

[0003] Magnetic components, such as electronic transformers or inductors, generally include a conductor (such as a winding) wound around a core. They come in a variety of shapes and sizes and can perform a variety of functions (e.g., energy storage, enabling soft-switching operation of converters).

[0004] Conventional high-power, high-frequency inductor designs are typically constructed with a core structure having a single air gap. The flux density distribution in these inductors is highly non-uniform, resulting in low energy density, relatively high energy loss, and a larger footprint. Recently, various multi-gap core structures with pot cores have been proposed. One example can be found in Non-Patent Document 1. However, the structure disclosed in Non-Patent Document 1 is difficult to manufacture and assemble because it consists of multiple annular rings with different radii. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments disclosed herein each have several aspects, no single one of which is solely responsible for the desirable attributes of the present disclosure. Without limiting the scope of the present disclosure, its more prominent features will now be briefly discussed. After considering this description, and particularly after reading the section entitled "Detailed Description of the Invention," one will appreciate how the features of the embodiments described herein provide advantages over existing inductor structures.

[0006] One embodiment is an inductor structure comprising an upper core having at least an upper central flux shaping plate, a lower core, a central post vertically disposed between the upper central flux shaping plate and the lower core, and a winding disposed between the upper core and the lower core and surrounding the central post, wherein the central flux shaping plate may partially overlap at least a portion of the winding.

[0007] In the above inductor structure, the inductor structure further comprises an enclosure that encloses the upper core, the lower core, and the winding.

[0008] In the above inductor structure, the upper core further comprises a first upper flux shaping plate and a second upper flux shaping plate disposed on opposite sides of the upper central flux shaping plate.

[0009] In the above inductor structure, a first upper air gap is disposed between the first upper flux shaping plate and the upper central flux shaping plate, and a second air gap is disposed between the upper central flux shaping plate and the second upper flux shaping plate.

[0010] In the above inductor structure, the upper core further includes a first additional upper flux shaping plate disposed between the upper central flux shaping plate and the first upper flux shaping plate, and a second additional upper flux shaping plate disposed between the upper central flux shaping plate and the second upper flux shaping plate.

[0011] In the above inductor structure, the inductor structure further comprises a heat sink disposed below the lower core.

[0012] In the above inductor structures, the windings are integrated into the printed circuit board.

[0013] In the above inductor structure, the winding comprises multiple winding layers.

[0014] In the above inductor structure, the winding is located at the midpoint between the upper and lower cores.

[0015] In the above inductor structure, the windings are positioned adjacent to the lower core.

[0016] In the above inductor structure, a portion of the winding is disposed outside the inductor structure.

[0017] Another aspect is an inductor structure comprising: an upper core comprising an upper central flux shaping plate, a first upper flux shaping plate, and a second upper flux shaping plate; a lower core comprising a lower central flux shaping plate, a first lower flux shaping plate, and a second lower flux shaping plate; a central post vertically disposed between the upper central flux shaping plate and the lower central flux shaping plate; and a winding disposed between the upper core and the lower core and surrounding the central post.

[0018] In the above inductor structure, the first upper air gap is disposed between the first upper flux shaping plate and the upper central flux shaping plate.

[0019] In the above inductor structure, the second air gap is disposed between the upper central flux shaping plate and the second upper flux shaping plate.

[0020] In the above inductor structure, the first lower air gap is disposed between the first lower flux shaping plate and the lower central flux shaping plate.

[0021] In the above inductor structure, the second air gap is disposed between the lower central flux shaping plate and the second lower flux shaping plate.

[0022] In the above inductor structure, the upper core further includes a first additional upper flux shaping plate disposed between the upper central flux shaping plate and the first upper flux shaping plate, and a second additional upper flux shaping plate disposed between the upper central flux shaping plate and the second upper flux shaping plate.

[0023] In the above inductor structure, the lower core further includes a first additional lower flux shaping plate disposed between the lower central flux shaping plate and the first lower flux shaping plate, and a second additional lower flux shaping plate disposed between the lower central flux shaping plate and the second lower flux shaping plate.

[0024] In the above inductor structure, the winding comprises multiple winding layers.

[0025] In the above inductor structure, the winding is located at the midpoint between the upper and lower cores.

[0026] Any feature of an embodiment is applicable to all embodiments identified herein. Furthermore, any feature of an embodiment is described herein and can be independently, partially, or entirely combined in any way with other embodiments, e.g., one, two, or three or more embodiments can be entirely or partially combined. Furthermore, any feature of an embodiment can be optional with respect to other embodiments. [Brief explanation of the drawings]

[0027] The foregoing and other features of the present disclosure will become more fully apparent from the following description and appended claims, taken in conjunction with the accompanying drawings, in which: The present disclosure will be described with additional specificity and detail through the use of the accompanying drawings, with the understanding that these drawings illustrate only some embodiments in accordance with the present disclosure and should not be considered as limiting its scope.

[0028] [Figure 1] 1 illustrates a simplified schematic diagram of an exemplary high frequency inductor and transformer design;

[0029] [Figure 2] 1 illustrates an example of an inductor structure with flux molding, according to some embodiments.

[0030] [Figure 3A] 1 illustrates an example of a cross-sectional view of a closed pot core structure with flux molding, according to some embodiments.

[0031] [Figure 3B] 3B illustrates an exemplary perspective view of the closed pot core structure of FIG. 3A, according to some embodiments.

[0032] [Figure 3C] 3B illustrates the near-field distribution of the closed pot core structure of FIG. 3A, according to some embodiments.

[0033] [Figure 3D] 1 illustrates comparative stray fields.

[0034] [Figure 3E] 1 illustrates a graph of resistive loss comparison between layers of inductor devices having the same inductance and the same footprint.

[0035] [Figure 4A] 1 illustrates an example of an open EE inductor structure with flux molding on the top and bottom cores, according to some embodiments. [Figure 4B] 1 illustrates an example of an open EE inductor structure with flux molding on the top and bottom cores, according to some embodiments. [Figure 4C] 1 illustrates an example of an open EE inductor structure with flux molding on the top and bottom cores, according to some embodiments.

[0036] [Figure 4D] 4A-4C illustrate flux lines for the open EE inductor structure shown in FIG. 4A-4C in a two-dimensional simulation.

[0037] [Figure 4E] 1 illustrates an example of an open EE inductor structure with flux molded plates on the top and bottom cores, according to some embodiments. [Figure 4F] 1 illustrates an example of an open EE inductor structure with flux molded plates on the top and bottom cores, according to some embodiments. [Figure 4G] 1 illustrates an example of an open EE inductor structure with flux molded plates on the top and bottom cores, according to some embodiments. Reference numbers added.

[0038] [Figure 4H] 1 illustrates another example of an open EE inductor structure having flux molded plates formed on the top and bottom cores, according to some embodiments. [Figure 4I] 1 illustrates another example of an open EE inductor structure having flux molded plates formed on the top and bottom cores, according to some embodiments.

[0039] [Figure 5A] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments. [Figure 5B]1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments. [Figure 5C] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments.

[0040] [Figure 5D] 5A-5C illustrate flux lines for the open EE inductor structure shown in FIGS. 5A-5C in a two-dimensional simulation.

[0041] [Figure 5E] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments. [Figure 5F] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments. [Figure 5G] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments.

[0042] [Figure 5H] 1 illustrates another example of an open EE inductor structure having flux molding formed only on the top core, according to some embodiments.

[0043] [Figure 6A] Illustrates the assembly of a multi-gap EE design. [Figure 6B] Illustrates the assembly of a multi-gap EE design. [Figure 6C] Illustrates the assembly of a multi-gap EE design.

[0044] [Figure 6D] 1 illustrates a pot core structure.

[0045] [Figure 7A] 1 illustrates the flux density distribution of a wire-wound inductor structure with a single air gap.

[0046] [Figure 7B] 1 illustrates an example of a wirewound flux-formed inductor structure with a multi-gap design in two side legs, according to some embodiments. [Figure 7C] 1 illustrates an example of a wirewound flux-formed inductor structure with a multi-gap design in two side legs, according to some embodiments.

[0047] [Figure 7D] 7B and 7C illustrate flux density distributions for the wire-wound flux-formed inductor structures shown in FIGS. 7B and 7C, according to some embodiments.

[0048] [Figure 7E] 1 illustrates another example of a wirewound flux-formed inductor structure with a multi-gap design in all legs, according to some embodiments. [Figure 7F] 1 illustrates another example of a wirewound flux-formed inductor structure with a multi-gap design in all legs, according to some embodiments. [Figure 7G] 1 illustrates another example of a wirewound flux-formed inductor structure with a multi-gap design in all legs, according to some embodiments.

[0049] [Figure 7H] 7E-7G illustrate flux density distributions for the wirewound flux-shaped inductor structures shown in FIGS. 7E-7G, according to some embodiments.

[0050] [Figure 8A] 1 illustrates a toroid inductor having a single air-gap toroidal core.

[0051] [Figure 8B]1 illustrates a toroid inductor having a multi-air gap toroidal core, according to some embodiments.

[0052] [Figure 8C] 8C illustrates the current density distribution of the toroid inductor having the multi-air-gap toroidal core shown in FIG. 8B, according to some embodiments.

[0053] Embodiments of the present disclosure and their advantages are best understood by referring to the following detailed description. It should be understood that like reference numerals have been used to identify like elements shown in one or more of the figures, and that the elements shown in these figures are intended to illustrate embodiments of the present disclosure and not to limit the disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0054] Various embodiments of electronic inductors are provided herein, including a sealed pot core structure with a flux-molded plate on the core's central post. Inductor structures with open-to-earth core (e.g., cores with an EE shape) configuration can potentially generate large stray magnetic fields, potentially causing electromagnetic compatibility (EMC) issues for nearby components. To address these deficiencies, various embodiments are provided to minimize stray magnetic fields. Specifically, the present disclosure provides various embodiments, including a sealed pot core structure with a flux-molded plate on the core's central post. This structure can maintain a strong magnetic field confined within the core structure while simultaneously minimizing stray magnetic fields and providing the advantage of reduced high-frequency conduction losses in copper due to flux molding.

[0055] According to various embodiments, the multi-gap EE structures described herein can include plates of the same size, allowing for simpler manufacturing and easier assembly. Furthermore, in some embodiments, the proposed structures include a sealed pot core structure with flux-molded plates, which can solve the problem of stray fields (from magnetic structures) and improve upon conventional inductor designs.

[0056] Some embodiments may include an open EE core structure with 0, 1, 2, ..., n plates in the top and bottom cores. Some embodiments may include an open EE core structure with 0, 1, 2, ..., n plates in the top core only. Some embodiments may include a wirewound flux-formed inductor structure with distributed air gaps. Some embodiments may include a toroid inductor with a multi-air-gap toroidal core.

[0057] In some embodiments, the open-EE inductor structure has air gaps with or without ferrite plates in strategic locations that allow for reshaping of the magnetic flux to minimize high-frequency AC resistance and, therefore, copper conduction losses. The open-EE inductor structure can have gaps or plates in only the top core or in both the top and bottom cores. The presence of air gaps / flux-shaping plates in both the top and bottom cores allows for flux shaping of the windings from both sides. However, this structure may be useful in designs without a heat sink, as the presence of an air gap on the bottom core plate can cause significant stray losses at the heat sink surface due to its proximity to the core bottom plate.

[0058] In comparison, an open EE inductor structure with a gap / plate in only the top core may have flux forming in the winding from only one side, but because there is no air gap in the bottom core plate, heat sinking losses due to stray fields may be minimal.

[0059] Existing multi-gap pot core structures require multiple annular rings of different radii, which must be manufactured and assembled together. In comparison, the multi-gap EE structure embodiments described herein can include plates of the same size, allowing for simpler manufacturing and easier assembly. Furthermore, the open EE structure can also allow windings to be placed very close to the heat sink where no core is present. However, this can cause some inductive losses in the heat sink.

[0060] Wirewound flux-formed inductor structures with distributed air gaps can use square / rectangular plates to improve energy density due to more uniform flux density within the core with multiple air gaps, resulting in a smaller footprint compared to existing structures with a single air gap. Multi-gap inductor designs can also be envisioned using toroidal cores, allowing for similar benefits of reduced footprint and lower losses compared to designs with a single air gap.

[0061] Various embodiments can be used in one or more of the following: on-board chargers for electric vehicles, stationary energy storage devices (such as Powerwall, Megapack, or Supercharger), autonomous driving hardware, or any power electronic converter that requires energy storage and has soft-switching requirements. Various embodiments also cover a variety of concepts / structures that can be used in any power converter designed for any of the above applications. In some embodiments, the core structure can be made of magnetic materials such as ferrite and powder core. Various embodiments are advantageous over single-air-gap inductors or inductors without air gaps designed using low-permeability materials, which are inefficient designs without flux-shaping features or designs that feature flux-shaping but have significant near-field effects. According to various embodiments, multi-gap designs can result in a smaller footprint, which helps significantly improve the power density of the converter. Furthermore, planar, high-power, high-frequency inductors can significantly increase power capabilities at low cost and enable more efficient production of components for electric vehicles or energy storage devices.

[0062] FIG. 1 illustrates a schematic example of a high-frequency inductor and transformer design 100. In some embodiments, the high-frequency inductor design 100 can include an inductor structure 110 (e.g., for high-power and high-frequency applications) and a transformer structure 120. However, as shown in FIG. 1, the inductor design 100 can be used in resonant converter applications. In some embodiments, each of the inverter structure 110 and the transformer structure 120 can be implemented as separate components. Furthermore, separate high-power and high-frequency inductors will be required in new multilevel soft-switching inverter designs that do not require isolation and / or turns ratio modifications.

[0063] FIG. 2 illustrates an example of various inductor structures 200 with flux molding, according to some embodiments. The inductor structure with flux molding may include a flux molding plate on the center post in the sealed pot core 210 (Example 1: see, e.g., FIGS. 3A and 3B). The inductor structure with flux molding may also include two or more flux molding plates (0, 1, 2, ..., n) on the upper and lower cores in the open EE structure 220 (Example 2: see, e.g., FIGS. 4A-4C and 4E-4I). The inductor structure with flux molding may include two or more flux molding plates (0, 1, 2, ..., n) only on the upper core in the open EE structure 230 (Example 3: see, e.g., FIGS. 5A-5C and 5E-5I). The inductor structure with flux molding may further include multi-gaps in some or all core legs using Litz wire 240 (Example 4: see, e.g., FIGS. 7B, 7C and 7E-7G). The inductor structure with flux molding may further include a toroid core with a multi-gap design using foil / litz wire 250 (Example 5: see, e.g., FIG. 8B). The above designs are merely examples, and the inductor structure with flux molding may include other designs.

[0064] FIG. 3A illustrates an example cross-sectional view of a sealed pot core structure 300 with a flux molded plate 310, according to some embodiments. FIG. 3B illustrates example perspective views of sealed pot core structures of various shapes, according to some embodiments. FIG. 3C illustrates the near-field distribution of the sealed pot core structure of FIG. 3A, according to some embodiments. FIG. 3D illustrates comparative stray magnetic fields. FIG. 3E illustrates a graph of resistive loss comparison between layers for the same inductance and footprint.

[0065] 3A , the sealed pot core structure 300 can include a flux shaping plate 310 disposed on top of a central post 312. In some embodiments, the flux shaping plate 310 can form the top core. In some embodiments, the flux shaping plate 310 can have a width sized to at least partially vertically overlap one or more of the first winding portion 330 or the second winding portion 340. In some examples, the width of the flux shaping plate 310 can be greater than the width of the central post 312. In some embodiments, the central post 312 can be disposed perpendicular to the bottom core 314. In some examples, the bottom core 314 can include sidewalls 314A, 314B (hereinafter, the bottom core will be generally referred to as including the sidewalls 314A, 314B). The windings (e.g., including first winding portion 330 and second winding portion 340) can be disposed between flux forming plate 310 and lower core 314. In some cases, an enclosure 316 can be used to enclose flux forming plate 310 (e.g., upper core), center post 312, lower core 314, and the windings (e.g., including first winding portion 330 and second winding portion 340). FIG. 3B illustrates examples of various shapes of inductor structure 300. For example, FIG. 3B-1 illustrates an inductor structure 300 having a plurality of inductor portions 330 and 340. As shown, the inductor structure can have a circular structure. As shown in FIG. 3B-2, the inductor structure can also have a rectangular structure. Although such structures have different shapes, these structures can include various shapes of the enclosure 316, flux forming plate 310, winding 350 of FIG. 3B-1 (shown only in FIGS. 3B-1 and 3B-2, which can include PCD windings, which are not shown in FIG. 3B-2), center post 312, and lower core 314.

[0066] As shown in the near-field distribution of FIG. 3C , the sealed pot core structure 300 can provide minimal stray magnetic fields, for example, by using a flux shaping plate 310, which can block at least some of the stray magnetic fields. For example, as shown in FIG. 3C , most of the magnetic field is confined within an inductor structure, such as the sealed pot core structure 300 shown in FIG. 3A . As further shown in FIG. 3D , the current density is significantly more uniform (360) in the sealed pot core structure 300 including the flux shaping plate compared to a conventional design (350) that does not include the flux shaping plate. Furthermore, the current density of the sealed pot core structure 300 including the flux shaping plate (370) with a non-optimized shape can also be significantly more uniform compared to the conventional design (350). Therefore, the simulation results shown in FIGS. 3C and 3D demonstrate minimal stray magnetic fields by using a flux shaping plate. Referring to FIG. 3E , the sealed pot core structure 300 can also have reduced resistive losses when the flux shaping plate 310 is used. For example, each layer turn (each value on the x-axis of FIG. 3E ) corresponds to a high-frequency (e.g., 272 KHz) resistive loss and a low-frequency resistive loss with and without a flux forming plate, with each bar corresponding to a relative layer turn. The right bar (382) can represent the resistive loss without a flux forming plate at high frequencies, the middle bar (384) can represent the resistive loss with a flux forming plate at high frequencies, and the left bar (386) can represent the resistive loss at low frequencies. As illustrated in FIG. 3E , resistive loss can increase at high frequencies. As further illustrated in FIG. 3E , the increase in resistive loss at high frequencies can be minimized by implementing a flux forming plate, as can be seen from the comparison of bar 382 (without a flux forming plate) with bar 384 (with a flux forming plate), which provides minimized resistive loss.In some embodiments, a sealed pot core structure, such as sealed pot core structure 300, can be utilized in designs that can be incorporated into external components such as heat sinks / cold spaces, metal covers, etc. where near-field concerns may be a concern.

[0067] FIG. 4A illustrates a two-dimensional view of an open EE inductor structure 400, FIG. 4B illustrates an exploded view of the open EE inductor structure 400, and FIG. 4C illustrates an assembled view of the open EE inductor structure 400. FIGS. 4A, 4B, and 4C illustrate an example of an open EE inductor structure 400 with flux shaping formed on the top and bottom cores, according to some embodiments. FIG. 4D illustrates flux lines of the open EE inductor structure shown in FIGS. 4A-4C in a two-dimensional simulation, according to some embodiments. FIGS. 4E, 4F, and 4G illustrate an example of an open EE inductor structure 450 with flux shaping plates on the top and bottom cores, according to some embodiments. FIGS. 4H and 4I illustrate another example of an open EE inductor structure 480 with flux shaping plates on the top and bottom cores, according to some embodiments.

[0068] 4A-4C , the open EE inductor structure 400 may include an upper core 410, a lower core 430, and a PCB winding 420 disposed between the upper core 410 and the lower core 430. The upper core 410 may include an upper central flux forming plate 414 disposed on or coupled to a top of a central post 418. In some embodiments, the upper core 410 may also include a first upper flux forming plate 412 and a second upper flux forming plate 416. In some examples, the first upper flux forming plate 412 and the second upper flux forming plate 416 are disposed on opposite sides of the central upper flux forming plate 414. The upper core 410 of the open EE inductor structure 400 may further include two upper air gaps 422A, 422B. For example, the first upper air gap 422A may be formed between the first upper flux forming plate 412 and the upper central flux forming plate 414. Additionally, a second upper air gap 422B can be formed between the second upper flux shaping plate 416 and the upper central flux shaping plate 414.

[0069] As further shown in FIGS. 4A-4C , the lower core 440 may include a lower central flux forming plate 434 disposed on or coupled to a lower portion of the central post 418. The lower core 430 may include a lower central flux forming plate 434 disposed on or coupled to a lower portion of the central post 418. In some embodiments, the lower core 430 may also include a first lower flux forming plate 432 and a second lower flux forming plate 436. In some examples, the first lower flux forming plate 432 and the second lower flux forming plate 436 are disposed on opposite sides of the central lower flux forming plate 434. The lower core 430 of the open EE inductor structure 400 may further include two lower air gaps 424A, 424B. For example, the first lower air gap 424A can be formed between the first lower flux forming plate 432 and the lower central flux forming plate 434. Additionally, a second lower air gap 424B can be formed between the second lower flux shaping plate 436 and the lower central flux shaping plate 434. In some embodiments, the open EE inductor structure 400 can include a total of three upper flux shaping plates (e.g., the first upper flux shaping plate 412, the central upper flux shaping plate 414, and the second upper flux shaping plate 416) and a total of three lower shaping plates (e.g., the first lower flux shaping plate 432, the central lower flux shaping plate 434, and the second lower flux shaping plate 436), each at least partially vertically overlapping the winding 420 (e.g., a PCB winding). FIG. 4C illustrates an example of an assembled view of the EE inductor structure 400. For example, the assembled EE inductor structure 400 may include an upper core 410 (having a first upper flux forming plate 412, a central upper flux forming plate 414, and a second upper flux forming plate 416), a lower core 430 (having a first lower flux forming plate 432, a central lower flux forming plate 434, and a second lower flux forming plate 436), a central post 418, and a winding 420 (e.g., a PCB winding).4C, the winding 420 can surround the central post 418. In some examples, a portion 420A of the winding 420 may not be included in the EE inductor structure 400.

[0070] FIG. 4D illustrates the flux lines on one side of the open EE inductor structure 400 shown in FIGS. 4A-4C in a two-dimensional simulation, according to some embodiments. As shown in FIG. 4D, the flux lines on one side of the open EE inductor structure 400 can be substantially parallel to the winding layers (e.g., layer 422). This design can be advantageous over inductor structures that do not include flux-shaping plates, in which the flux lines are substantially perpendicular to the winding layers. As a result, stray magnetic fields or AC winding losses at high frequencies can be minimized. The eight winding layers illustrated in FIG. 4D are merely an example, and the present disclosure is not limited thereto. For example, more than eight winding layers or fewer than eight winding layers can be used.

[0071] 4E-4G show two-dimensional, exploded, and assembled views, respectively, of an example open EE inductor structure 450 having flux shaping plates on the top and bottom cores according to some embodiments of the open EE inductor structure 400. Referring to FIGS. 4E-4G, the open EE inductor structure 450 can include two additional top flux shaping plates 452 on the top core 410 and two additional bottom flux shaping plates 462 on the bottom core 430. In some embodiments, the open EE inductor structure 450 can include a total of five upper flux shaping plates (e.g., first upper flux shaping plate 412, first additional upper flux shaping plate 452A, central upper flux shaping plate 414, second additional upper flux shaping plate 452B, and second upper flux shaping plate 416) and a total of five lower shaping plates (e.g., first lower flux shaping plate 432, first additional lower flux shaping plate 462A, central lower flux shaping plate 434, second additional lower flux shaping plate 462B, and second lower flux shaping plate 436), each at least partially vertically overlapping the winding 420.

[0072] In some embodiments, the upper core 410 may include a first upper flux forming plate 412, a first additional upper flux forming plate 452A, a central upper flux forming plate 414, a second additional upper flux forming plate 452B, and a second upper flux forming plate 416. In some examples, two of the plates (the first upper flux forming plate 412 and the first additional upper flux forming plate 452A) and the other two plates (the second upper flux forming plate 416 and the second additional upper flux forming plate 452B) are disposed on opposite sides of the central upper flux forming plate 414. In some embodiments, the upper core 410 may include air gaps 454A-454D. For example, a first upper air gap 454A can be formed between the first upper flux forming plate 412 and the first additional upper flux forming plate 452A, a second upper air gap 454B can be formed between the first additional upper flux forming plate 452A and the central upper flux forming plate 414, a third upper air gap 454C can be formed between the central upper flux forming plate 414 and the second additional upper flux forming plate 452B, and a fourth upper air gap 454D can be formed between the second additional upper flux forming plate 452B and the second upper flux forming plate 416.

[0073] FIG. 4E illustrates a two-dimensional view of open EE inductor structure 450, and FIG. 4F illustrates an exploded view of open EE inductor structure 450. As further shown in FIGS. 4E-4F , in some embodiments, lower core 430 can include a first lower flux shaping plate 432, a first additional lower flux shaping plate 462A, a central lower flux shaping plate 434, a second additional lower flux shaping plate 462B, and a second lower flux shaping plate 436. In some examples, two plates (first lower flux shaping plate 432 and first additional lower flux shaping plate 462A) and two other plates (second lower flux shaping plate 436 and second additional lower flux shaping plate 462B) are disposed on opposite sides of central lower flux shaping plate 434. In some embodiments, lower core 430 can include air gaps 456A-456D. For example, a first lower air gap 456A can be formed between the first lower flux shaping plate 432 and the first additional lower flux shaping plate 462A, a second lower air gap 456B can be formed between the first additional lower flux shaping plate 462A and the central lower flux shaping plate 434, a third lower air gap 456C can be formed between the central lower flux shaping plate 434 and the second additional lower flux shaping plate 462B, and a fourth lower air gap 454D can be formed between the second additional lower flux shaping plate 462B and the second lower flux shaping plate 436. Thus, the open EE inductor structure 450 can include four upper air gaps 454A-454D and four lower air gaps 456A-456D. With this design, stray magnetic fields or AC winding losses at high frequencies can be minimized.

[0074] 4G illustrates an example of an assembled view of an open EE inductor structure 450. For example, the assembled open EE inductor structure 450 can include an upper core 410 (having a first upper flux forming plate 412, a first additional upper flux forming plate 452A, a central upper flux forming plate 414, a second additional upper flux forming plate 452B, and a second upper flux forming plate 416), a lower core 430 (having a first lower flux forming plate 432, a first additional lower flux forming plate 462A, a central lower flux forming plate 434, a second additional lower flux forming plate 462B, and a second lower flux forming plate 436), a central post 418, and a winding 420 (e.g., a PCB winding). As illustrated in FIG. 4G, the winding 420 can surround the central post 418. In some examples, a portion 420A of the winding 420 may not be included in the open EE inductor structure 450.

[0075] 4H illustrates another example of an open EE inductor structure 480 having flux shaping plates formed on the top core 410 and the bottom core 430, according to some embodiments. Referring to FIGS. 4H and 4I, the open EE inductor structure 480 can include four additional top flux shaping plates (482A, 482B, 482C, and 482D) on the top core 410 and four additional bottom flux shaping plates (492A, 492B, 492C, and 492D) on the bottom core 430. According to this design, the open EE inductor structure 480 can include a total of seven top flux shaping plates and seven bottom shaping plates, with each plate at least partially vertically overlapping a PCB winding. For example, the upper core 410 can include a first upper flux shaping plate 412, a first additional upper flux shaping plate 482A, a second additional upper flux shaping plate 482B, a central upper flux shaping plate 414, a third additional upper flux shaping plate 482C, a fourth additional upper flux shaping plate 482D, and a second upper flux shaping plate 416. Similarly, the lower core 430 can include a first lower flux shaping plate 432, a first additional lower flux shaping plate 492A, a second additional lower flux shaping plate 492B, a central lower flux shaping plate 434, a third additional lower flux shaping plate 462C, a fourth additional lower flux shaping plate 462D, and a second lower flux shaping plate 436. As a result, the open EE inductor structure 480 can include six upper air gaps.For example, six upper air gaps can be disposed: (1) between the first upper flux forming plate 412 and the first additional upper flux forming plate 482A; (2) between the first additional upper flux forming plate 482A and the second additional upper flux forming plate 482B; (3) between the second additional upper flux forming plate 482B and the central upper flux forming plate 414; (4) between the central upper flux forming plate 414 and the third additional upper flux forming plate 482C; (5) between the third additional upper flux forming plate 482C and the fourth additional upper flux forming plate 482D; and (6) between the fourth additional upper flux forming plate 482D and the second upper flux forming plate 416. Additionally, six lower air gaps can be disposed: (1) between the first lower flux forming plate 432 and the first additional lower flux forming plate 492A, (2) between the first additional lower flux forming plate 492A and the second additional lower flux forming plate 492B, (3) between the second additional lower flux forming plate 492B and the central lower flux forming plate 434, (4) between the central lower flux forming plate 434 and the third additional lower flux forming plate 462C, (5) between the third additional lower flux forming plate 462C and the fourth additional lower flux forming plate 462D, and (6) between the fourth additional lower flux forming plate 462D and the second lower flux forming plate 436. In some embodiments, the winding 420 can be disposed between the upper core 410 and the lower core 430. In these embodiments, the winding 420 can surround the central post 418.

[0076] In some embodiments, as illustrated in FIG. 4I, the example open EE inductor structure 480 illustrated in FIG. 4H can further include multiple plates 494 on each sidewall of the lower core 430 and multiple coils 496 surrounding the central post 418.

[0077] 4A-4I are merely examples, and the present disclosure is not limited thereto. For example, more than seven upper flux forming plates and / or more than seven lower forming plates can be provided. Also, more than six upper air gaps and / or more than six lower air gaps can be provided.

[0078] 5A-5C illustrate two-dimensional, exploded, and assembled views, respectively, of an example open EE inductor structure 500 having flux molding formed only on the top core, according to some embodiments. Referring to FIGS. 5A-5C, the open EE inductor structure 500 can include an upper core 510, a lower core 530, and a PCB winding 520 generally disposed between the upper core 510 and the lower core 530. The upper core 410 can include three flux molding plates 512-516. The open EE inductor structure 500 can include two upper air gaps 522 formed between the center flux molding plate 514 and the side flux molding plates 512 and 516. The lower core 530 does not include a flux molding plate. The open EE inductor structure 500 may not include a lower air gap. A heat sink / cooling plate 540 can be provided below the lower core 530. According to this design, the open EE inductor structure 500 can include a total of three upper flux forming plates, each plate at least partially vertically overlapping a PCB winding 520. FIG. 5C illustrates an example of an assembled view of the EE inductor structure 500. For example, the assembled EE inductor structure 500 can include an upper core 510 (having a first upper flux forming plate 512, a central upper flux forming plate 514, and a second upper flux forming plate 516), a lower core 530, a central post 518, and a winding 520 (e.g., a PCB winding). As illustrated in FIG. 5C, the winding 520 can surround the central post 518. In some examples, a portion 520A of the winding 520 may not be included in the EE inductor structure 500.

[0079] 5A-5C in a two-dimensional simulation. As shown in FIG. 5D, the flux lines 524 of the open EE inductor structure 500 can be substantially parallel to the windings 520 (e.g., winding layers). This design can be advantageous over conventional inductor structures that do not include flux-shaping plates, in which the flux lines are substantially perpendicular to the winding layers; as a result, stray magnetic fields or AC winding losses at high frequencies can be minimized.

[0080] 5E, 5F, and 5G illustrate another example of an open EE inductor structure 550 with flux molding formed only on the upper core, according to some embodiments. Referring to FIGS. 5E-5G, the open EE inductor structure 550 can include two additional upper flux molding plates 552 formed only on the upper core. According to this design, the open EE inductor structure 550 can include a total of five upper flux molding plates 552, with each plate at least partially vertically overlapping the PCB windings. As a result, the open EE inductor structure 550 can include a total of four upper air gaps 554 (only one upper air gap has a designated lead and reference number in FIG. 5E). This design can be used to shape the electromagnetic field generated by the PCB windings. In some embodiments, a heat sink 540 can be disposed (e.g., assembled) below the lower core. The heat sink 540 can aid in cooling the core / windings. This disclosure does not limit the type and / or number of heat sinks. These types and / or numbers of heat sinks can be determined based on the particular application.

[0081] 5E-5G show two-dimensional, exploded, and assembled views of an example open EE inductor structure 550 having a flux shaping plate on each upper core according to some embodiments of the open EE inductor structure 500. Referring to FIGS. 5E-5G, the open EE inductor structure 550 can include two additional upper flux shaping plates 552 on the upper core 510. In some embodiments, the open EE inductor structure 550 can include a total of five upper flux shaping plates (e.g., first upper flux shaping plate 512, first additional upper flux shaping plate 552A, center upper flux shaping plate 514, second additional upper flux shaping plate 552B, and second upper flux shaping plate 516), each of which at least partially vertically overlaps the winding 420. The open EE inductor structure 550 can be configured to minimize stray electromagnetic fields generated by the PCB windings from the open EE inductor structure 550. In some embodiments, a heat sink 540 at the bottom of the open EE inductor structure 550 can be assembled to cool the core / windings.

[0082] 5E and 5F , the upper core 510 can include a first upper flux forming plate 512, a first additional upper flux forming plate 552A, a central upper flux forming plate 514, a second additional upper flux forming plate 552B, and a second upper flux forming plate 516. In some examples, two of the plates (the first upper flux forming plate 512 and the first additional upper flux forming plate 552A) and the other two plates (the second upper flux forming plate 516 and the second additional upper flux forming plate 552B) are disposed on opposite sides of the central upper flux forming plate 514. In some embodiments, the upper core 510 can include air gaps 554A-554D. For example, a first upper air gap 554A can be formed between the first upper flux forming plate 512 and the first additional upper flux forming plate 552A, a second upper air gap 554B can be formed between the first additional upper flux forming plate 552A and the central upper flux forming plate 514, a third upper air gap 554C can be formed between the central upper flux forming plate 514 and the second additional upper flux forming plate 552B, and a fourth upper air gap 554D can be formed between the second additional upper flux forming plate 552B and the second upper flux forming plate 416.

[0083] 5G illustrates an example of an assembled view of an open EE inductor structure 550. For example, the assembled open EE inductor structure 550 can include an upper core 510 (having a first upper flux forming plate 512, a first additional upper flux forming plate 552A, a central upper flux forming plate 514, a second additional upper flux forming plate 552B, and a second upper flux forming plate 516), a central post 518, a lower core 530, and a winding 520 (e.g., a PCB winding). As illustrated in FIG. 5G, the winding 520 can surround the central post 518. In some examples, a portion 520A of the winding 520 may not be included in the open EE inductor structure 550.

[0084] 5H illustrates another example of an open EE inductor structure 580 having flux shaping plates formed on the top core 510 and the bottom core 530, according to some embodiments. Referring to FIG. 5H, the open EE inductor structure 580 can include four additional top flux shaping plates (582A, 582B, 582C, and 582D) on the top core 510. According to this design, the open EE inductor structure 580 can include a total of seven top flux shaping plates, each at least partially overlapping the PCB windings vertically. For example, the top core 510 can include a first top flux shaping plate 512, a first additional top flux shaping plate 582A, a second additional top flux shaping plate 582B, a central top flux shaping plate 514, a third additional top flux shaping plate 582C, a fourth additional top flux shaping plate 582D, and a second top flux shaping plate 516. As a result, the open EE inductor structure 580 can include six upper air gaps. For example, the six upper air gaps can be disposed: (1) between the first upper flux shaping plate 512 and the first additional upper flux shaping plate 582A, (2) between the first additional upper flux shaping plate 582A and the second additional upper flux shaping plate 582B, (3) between the second additional upper flux shaping plate 582B and the central upper flux shaping plate 514, (4) between the central upper flux shaping plate 514 and the third additional upper flux shaping plate 582C, (5) between the third additional upper flux shaping plate 582C and the fourth additional upper flux shaping plate 582D, and (6) between the fourth additional upper flux shaping plate 582D and the second upper flux shaping plate 516. In some embodiments, the winding 520 can be disposed between the upper core 510 and the lower core 530. In these embodiments, the windings 520 may surround the central post 518 .

[0085] The above inductor structures illustrated in Figures 5A-5H are merely examples, and the present disclosure is not limited thereto. For example, a total of more than seven upper flux forming plates can be provided. Also, more than six upper air gaps can be provided.

[0086] Figures 6A, 6B, and 6C illustrate the ease of assembly of the multi-gap EE design 600 compared to the pot core structure 650 shown in Figure 6D. For example, as shown in Figure 6A, an open EE inductor structure 600 with various multi-gap EE designs can be assembled with precise spacing of plates 625. For example, an example multi-gap EE design 600 shown in Figures 6A, 6B, and 6C can be assembled with gap 610, gap 620, and gap 630, respectively. Considering that these gaps 610, 620 can occur between straight parallel plates 625, equal spacing with consistent air gaps can be maintained across all plates 625.

[0087] 6D, a conventional multi-gap pot core design 650 requires assembling annular rings 640 of different radii. In the design of FIG. 6D, it can be difficult to ensure the same air gap length across the entire diameter of the ring.

[0088] 7A illustrates the flux density distribution of a conventional wire-wound inductor structure with a single air gap. As shown in FIG. 7A, a wire-wound inductor structure with a single air gap can reduce the magnetic field (e.g., as shown at 702) and therefore store less energy overall (as shown at 704).

[0089] 7B and 7C illustrate an example of a wirewound, flux-formed inductor structure 700 having a multi-gap design in two vertical side legs 710 and 720, according to some embodiments. In this embodiment, only the two vertical legs 710, 720 can include multi-gaps 730. While FIG. 7B shows a specific number of gaps 730 in the vertical legs 710, 720, this disclosure does not limit the number of gaps. In some embodiments, multi-gaps can be formed in horizontal legs, such as horizontal legs 740, 750. In some embodiments, as illustrated in FIG. 7C, wire can be wrapped through the horizontal and vertical gaps of the inductor structure shown in FIG. 7B. This embodiment can provide more efficient manufacturing compared to the embodiment of FIGS. 7E-7G, in which multi-gaps are formed in all legs.

[0090] 7D illustrates the flux density distribution of the wirewound flux-shaped inductor structure shown in FIGS. 7B and 7C, according to some embodiments. As shown in FIG. 7D, the flux density distribution of the wirewound flux-shaped inductor structure 700 exhibits an improved magnetic field due to more accumulation compared to the design of FIG. 7A.

[0091] Figures 7E, 7F, and 7G illustrate another example of a wire-wound, flux-formed inductor structure 750 having a multi-gap design on all legs, according to some embodiments. As shown in Figure 7E, multiple air gaps 730 can be formed in the vertical legs 710, 720 and the horizontal legs 740, 750. As shown in Figure 7F, a wire 760 can be wound around each of the vertical legs 710, 720 and the horizontal legs 740, 750. Figure 7F can be referred to as a Litz wire winding, and Figure 7G shows a prototype sample. As shown in Figure 7G, multiple air gaps 730 can be formed in the vertical legs 710, 720 and the horizontal legs 740, 750. Furthermore, a wire 760 can be wound around each of the vertical legs 710, 720 and the horizontal legs 740, 750.

[0092] 7H illustrates the flux density distribution of the wirewound flux-shaped inductor structure 750 shown in FIGS. 7E-7G, according to some embodiments. As shown in FIG. 7H, the wirewound flux-shaped inductor structure 750 can provide a substantially more uniform magnetic flux density distribution and can store more energy compared to the embodiment of FIG. 7B due to the multiple air gaps in all legs.

[0093] 8A illustrates a toroid inductor 800 having a single air gap 810 toroidal core. FIG. 8B illustrates a toroid inductor 850 having a multi-air gap toroidal core, according to some embodiments. The toroid inductor 800 can include a large single air gap 810. In some embodiments, the toroid inductor 850 can include multiple smaller air gaps 820, as illustrated in FIG. 8B.

[0094] 8C illustrates the current density distribution of a toroid inductor 850 having a multi-air-gap toroidal core shown in FIG. 8B, according to some embodiments. As shown in FIG. 8C, the toroid inductor 850 including the smaller multi-air gaps 860 can provide a more uniform current density distribution compared to the toroid inductor 800 including the large single air gap 810, thereby reducing high-frequency winding losses and increasing stored energy density.

[0095] It should be understood that a feature, material, characteristic, or group described in connection with a particular aspect, embodiment, or example is applicable to any other aspect, embodiment, or example described in this section or elsewhere in this specification, unless inconsistent therewith. All features disclosed in this specification (including the accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any combination, except combinations in which at least some of such features and / or steps are mutually exclusive. Protection is not limited to the details of any of the foregoing embodiments. Protection extends to any novel, or any novel combination of, features disclosed in this specification (including the accompanying claims, abstract, and drawings), or any novel, or any novel combination of steps of any method or process so disclosed.

[0096] Furthermore, certain features that are described in this disclosure in the context of separate embodiments can also be implemented in combination in a single implementation. Conversely, various features that are described in the context of a single implementation can also be implemented in multiple implementations separately or in any suitable subcombination. Furthermore, while features may be described above as acting in a particular combination, one or more features from a claimed combination can, in some cases, be deleted from the combination, and the combination can be claimed as a subcombination or a variation of the subcombination.

[0097] Furthermore, while operations may be depicted in the figures or described herein in a particular order, such operations need not be performed in the particular order shown, or in sequential order, or even all operations need to be performed to achieve desirable results. Other operations not shown or described may be incorporated into the example methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the described operations. Furthermore, operations may be rearranged or reordered in other implementations. Those skilled in the art will appreciate that in some embodiments, the actual steps performed in the illustrated and / or disclosed processes may differ from those shown in the figures. Depending on the embodiment, certain of the above steps may be omitted and other steps may be added. Furthermore, the features and attributes of the specific embodiments disclosed above may be combined in different ways to form additional embodiments, all of which are within the scope of the present disclosure. It should also be understood that the separation of various system components in the above implementations is not to be understood as requiring such separation in all implementations, and the described components and systems may generally be integrated together in a single product or packaged in multiple products. For example, any of the components of the energy storage system described herein may be provided separately or may be integrated (e.g., packaged together or attached together) to form an energy storage system.

[0098] For purposes of this disclosure, certain aspects, advantages, and novel features are described herein. Not necessarily all such advantages may be achieved in accordance with any particular embodiment. Thus, for example, one skilled in the art will recognize that the present disclosure may be embodied or implemented to achieve one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0099] Unless specifically stated otherwise or understood otherwise within the context in which it is used, conditional language such as "can," "could," "might," or "may" is generally intended to suggest that certain embodiments include certain features, elements, and / or steps, while other embodiments do not. Thus, such conditional language generally does not intend that features, elements, and / or steps are in any way required by one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included in or performed in any particular embodiment, with or without user input or prompting for input.

[0100] Conjunctions such as the phrase "at least one of X, Y, and Z," unless otherwise specified, are understood in the context in which they are generally used to convey that an item, term, etc. can be either X, Y, or Z. Thus, such conjunctions are generally not intended to imply that a particular embodiment requires the presence of at least one of X, at least one of Y, and at least one of Z.

[0101] As used herein, language of degree, such as "approximately," "about," "generally," and "substantially," denotes a value, amount, or characteristic that approaches a stated value, amount, or characteristic that still performs a desired function or achieves a desired result.

[0102] The scope of the present disclosure is not intended to be limited by the specific disclosure of embodiments in this section or elsewhere herein, but may be defined by the claims, as presented in this section or elsewhere herein, or as presented in the future. Claim language is to be interpreted broadly based on the language used in the claims, and not limited to the examples described in this specification or during prosecution of the application, which examples are to be construed as non-exclusive.

[0103] While specific embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the present disclosure. Indeed, the novel methods and systems described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions, and changes may be made in the systems and methods described herein without departing from the spirit of the disclosure. The appended claims and their equivalents are intended to cover such forms or modifications as are within the scope and spirit of the present disclosure. Accordingly, the scope of the present invention is defined solely by reference to the appended claims. [Prior art documents] [Non-patent literature]

[0104] [Non-Patent Document 1] J. Schafer, D. Bortis, and J.W. Kolar, "Novel Highly Efficient / Compact Automotive PCB Winding Inductors Based on the Compensating Air Gap Fringing Field Concept," IEEE Transactions on Power Electronics, Vol. 35, No. 9, pp. 9617-9631, September 2020, doi:10.1109 / TPEL.2020.2969295

Claims

1. an upper core having at least an upper central flux forming plate; A lower core; a center post disposed vertically between the upper center flux forming plate and the lower core; a winding disposed between the upper core and the lower core and surrounding the central post, wherein the central flux forming plate may partially overlap at least a portion of the winding; 1. An inductor structure comprising:

2. The inductor structure of claim 1 further comprising an enclosure enclosing the upper core, the lower core, and the windings.

3. 3. The inductor structure of claim 1, wherein the upper core further comprises a first upper flux shaped plate and a second upper flux shaped plate disposed on opposite sides of the upper central flux shaped plate, a first upper air gap being disposed between the first upper flux shaped plate and the upper central flux shaped plate, and a second air gap being disposed between the upper central flux shaped plate and the second upper flux shaped plate.

4. The upper core is a first additional upper flux forming plate disposed between the upper central flux forming plate and the first upper flux forming plate; a second additional upper flux forming plate disposed between the upper central flux forming plate and the second upper flux forming plate; The inductor structure of claim 3 further comprising:

5. The inductor structure of claim 1 , further comprising a heat sink disposed below the lower core.

6. 6. An inductor structure according to claim 1, wherein the winding is integrated into a printed circuit board.

7. 7. The inductor structure of claim 1, wherein the winding comprises multiple winding layers.

8. The inductor structure of claim 1 , wherein the winding is located at a midpoint between the upper core and the lower core.

9. The inductor structure of claim 1 , wherein the winding is disposed adjacent to the lower core.

10. The inductor structure of claim 1 , wherein a portion of the winding is disposed outside the inductor structure.

11. an upper core including an upper central flux forming plate, a first upper flux forming plate, and a second upper flux forming plate; a lower core including a lower central flux forming plate, a first lower flux forming plate, and a second lower flux forming plate; a center post vertically disposed between the upper and lower center flux forming plates; a winding disposed between the upper core and the lower core and surrounding the central post; 1. An inductor structure comprising:

12. 12. The inductor structure of claim 11, wherein a first upper air gap is disposed between the first upper flux shaped plate and the upper central flux shaped plate, and a second air gap is disposed between the upper central flux shaped plate and the second upper flux shaped plate.

13. 13. The inductor structure of claim 11 or 12, wherein a first lower air gap is disposed between the first lower flux shaped plate and the lower central flux shaped plate, and a second air gap is disposed between the lower central flux shaped plate and the second lower flux shaped plate.

14. The upper core is a first additional upper flux forming plate disposed between the upper central flux forming plate and the first upper flux forming plate; a second additional upper flux forming plate disposed between the upper central flux forming plate and the second upper flux forming plate; Further provided with The lower core is a first additional lower flux forming plate disposed between the lower central flux forming plate and the first lower flux forming plate; a second additional lower flux forming plate disposed between the lower central flux forming plate and the second lower flux forming plate; 14. The inductor structure of claim 11, further comprising:

15. 15. The inductor structure of claim 11, wherein the winding comprises multiple winding layers.

16. 16. The inductor structure of claim 11, wherein the winding is located at a midpoint between the upper core and the lower core.

Images