Planar matrix transformer and method

Abstract

An exemplary planar matrix transformer and methods of use and fabrication are disclosed having planar conductors arranged in planar and / or stacked configurations and surrounded by magnetic tiles that forms a core shell around the planar conductors. The exemplary planar matrix transformer can be formed with a short height profile and large surface area that has a strong heat dissipation capability in a low-profile configuration. The high heat dissipation capability facilitates high-density configurations and operations for the exemplary planar matrix transformer.

Description

PLANAR MATRIX TRANSFORMER AND METHODCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This PCT Application claims priority to, and the benefit of, U.S. Provisional Patent Application No. 63 / 586,658, filed September 29, 2023, entitled, “PLANAR MATRIX TRANSFORMER AND METHOD,” the content of which is incorporated by reference herein in its entirety.BACKGROUND

[0002] A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit or multiple circuits.

[0003] One common type of transformer is constructed by surrounding wires around a laminated steel magnetic core. A common design of laminated core is to form interleaved stacks of shaped steel sheets (e.g., E-shaped, Lshape, etc.). These cores can be assembled to be shaped as circular, oblong (oval), and rectangular.

[0004] Shapes of transformers are often not considered in a given power electronic application though transformers tend to be the largest and heaviest component in a power electronic system.

[0005] There are benefits to having alternative topologies for transformers that have a lower height profile and / or higher power density.SUMMARY

[0006] An exemplary planar matrix transformer and methods of use and fabrication are disclosed, having planar conductors arranged in planar and / or stacked configurations and surrounded by magnetic tiles that form a magnetic core shell around the planar conductors. The exemplary planar matrix transformer can be formed with a short height profile and large surface area that has a strong heat dissipation capability in a low-profile configuration. The high heat dissipation capability facilitates high-density configurations and operations for the exemplary planar matrix transformer.

[0007] In one implementation, multiple planar conductors corresponding to different legs of the transformer can be arranged in a stacked planar configuration. In another configuration, the multiple planar conductors can have multiple sections, each formed of conductors arranged in a planar configuration. The multiple sections for each leg of the transformer can be standardized as a module, and connecting cables can be fixably attached to one of multipleavailable connecting points on a given conductor module to adjust the turns ratio and the turn configurations for the planar matrix transformer. The modular design can facilitate flexible applications of the planar matrix transformer for various applications.

[0008] The planar matrix transformer is particularly beneficial for space constrained applications or power density applications, for example, electric vehicle power systems, electric vehicle charging systems, aircraft power systems, spacecraft power systems, and the like. In some embodiments, the planar matrix transformer can be employed in utility power distribution applications for its high heat dissipation capability and / or high-density operation configurations.

[0009] In an aspect, a system is disclosed comprising: a planar transformer comprising: a set of conductors, including a first conductor and second conductor, each of the first conductor and second conductor being arranged in a planar or stacked configuration; and a set of two or more magnetic material tiles (e.g., soft magnetic material, permanent magnetic) that forms a core-shell having a first portion and a second portion that house the set of planar or stacked conductors, wherein the first conductor is positioned in the first portion and second conductor is positioned in the second portion.

[0010] In some embodiments, the first conductor and the second conductor are arranged in the planar configuration and are correspondingly spaced apart (e.g., parallel adjacent) from each other.

[0011] In some embodiments, the first conductor and second conductor are arranged in the stacked configuration, and the first conductor defines at least a portion of a first winding, and the second conductor defines at least a portion of a second winding.

[0012] In some embodiments, the set of two or more magnetic material tiles comprises one or more arrays of magnetic material tiles, each having a center tile, wherein each center tile is concentric with the first conductor and second conductor.

[0013] In some embodiments, the planar transformer further comprises one or more thermal conductors.

[0014] Magnetic material tiles (e.g., soft magnetic material tiles) may include permanent magnets or active components that can generate a magnetic field. Soft magnetic material may include amorphous and nanocrystalline alloys as well as neodymium magnets, ferrite or metaferrite material.

[0015] In some embodiments, the first planar conductor is arranged in a first loop in the planar configuration, wherein the second planar conductor is arranged in a second loop in the planar configuration, wherein the first loop has an area and the second loop has an area, thearea of the first loop and the area of the second loop corresponding (e.g., parallel adjacent) to one another.

[0016] In some embodiments, the set of conductors includes a third conductor and fourth conductor, wherein the third conductor is connected to the first planar conductor and is arranged in a third loop in the planar configuration, wherein the fourth planar conductor is connected to the second conductor and is arranged in a fourth loop in the planar configuration, wherein the third loop has an area, and the fourth loop has an area, the area of the third loop and the area of the fourth loop corresponding (e.g., parallel adjacent) to one another.

[0017] In some embodiments, the set of two or more magnetic material tiles includes (i) a first set of permanent magnets arranged as tiles in the first portion of the core-shell and (ii) a second set of magnetic material arranged as tiled in the second portion of the magnetic core shell.

[0018] In some embodiments, the set of conductors is arranged in multiple sections as a module, the planar transformer including a set of connecting cables to fixably attached to one of multiple available connecting points on a given conductor module to adjust turns ratio and turn configurations for the planar matrix transformer.

[0019] In some embodiments, the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in a series configuration based on a second set of connection points located on the second and the fourth conductors.

[0020] In some embodiments, the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in a series configuration based on a second set of connection points located on the second and the fourth conductors.

[0021] In some embodiments, the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

[0022] In some embodiments, the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in parallelconfiguration based on a fourth set of connection points located on the second and the fourth conductors.

[0023] In some embodiments, the set of conductors is encased in an epoxy or polymer (e.g., potted).

[0024] In some embodiments, the system includes a power conversion circuit comprising at least one of an AC -DC converter, a DC-AC converter, an AC-AC converter, and a DC-DC converter, wherein the transformer is employed in the power conversion circuit.

[0025] In some embodiments, the system includes a second planar transformer comprising: a set of conductors, including a first conductor and second conductor, each of the first conductor and second conductor being arranged in a planar or stacked configuration; and a set of two or more magnetic material tiles that forms a core-shell having a first portion and a second portion that house the set of planar or stacked conductors, including the first conductor and second conductor, wherein the second planar transformer is arranged in parallel configuration to the planar transformer.

[0026] In some embodiments, the first conductor and second conductor are correspondingly spaced apart (e.g., parallel adjacent) from each other.

[0027] In some embodiments, the first conductor is arranged in the planar configuration along a first plane, wherein the third conductor is arranged in the planar configuration along a second plane, wherein the first plane and second plane are parallel to one another.

[0028] In some embodiments, the planar transformer is employed in an electric vehicle power system or an electric vehicle charging system.

[0029] In another aspect, a method is disclosed of fabricating a transformer comprising: providing a set of conductors, including a first conductor, second conductor, third conductor, and fourth conductor, each of the first conductor and second conductor being arranged in a predefined configuration (e.g., planar configuration), the configuration of the first conductor and second conductor being correspondingly spaced apart (e.g., parallel adjacent) from each other, wherein the third conductor is connectable to the first conductor and is arranged in a third loop in a pre-defmed configuration, wherein the fourth conductor is connectable to the second conductor and is arranged in a fourth loop in a pre-defmed configuration, wherein the third loop has an area and the fourth loop has an area, the area of the third loop and the area of the fourth loop corresponding (e.g., parallel adjacent) to one another, and wherein the first conductor, second conductor, third conductor, and fourth conductor are placed in proximity to a set of two or more magnetic material tiles (e.g., that forms a magnetic core shell having a first portion and a second portion that house the set of planar conductors); connecting a first cableor bus bar between at a position of multiple available positions on the first conductor and a position of multiple available positions on the third conductor to establish a first winding configuration for the first conductor and the second conductor; and connecting a second cable or bus bar between at a position of multiple available positions on the second conductor and a position of multiple available positions on the fourth conductor to establish a second winding configuration for the first conductor and the second conductor, wherein the connected positions on the first, second, third, and fourth conductors adjust at least one of turns ratio and turn configurations for the transformer.

[0030] In some embodiments, the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in a series configuration based on a second set of connection points located on the second and the fourth conductors.

[0031] In some embodiments, the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in a series configuration based on a second set of connection points located on the second and the fourth conductors.

[0032] In some embodiments, the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, and wherein the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

[0033] In some embodiments, the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, wherein the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

[0034] In some embodiments, the method includes providing power electronic equipment, connecting a third cable or bus bar to a first terminal of the power electronic equipment; and connecting a fourth cable or bus bar to a second terminal of the power electronic equipment.

[0035] Other systems, methods, features and / or advantages will be or may become apparent to one with skill in the art upon examination of the following drawings and detaileddescription. It is intended that all such additional systems, methods, features, and / or advantages be included within this description and be protected by the accompanying claims.BRIEF DESCRIPTION OF DRAWINGS

[0036] FIG. 1 depicts views of a system including a planar matrix transformer in accordance with certain embodiments of the present disclosure.

[0037] FIGS. 2A-2F depict proposed planar transformer configurations in accordance with certain embodiments of the present disclosure.

[0038] FIG. 3A depicts configurations of proposed planar transformers in accordance with certain embodiments of the present disclosure.

[0039] FIG. 3B shows a method of fabricating and configuring a transformer in accordance with certain embodiments of the present disclosure.

[0040] FIG. 4A depicts a structure and winding layout of an example planar transformer in accordance with certain embodiments of the present disclosure.

[0041] FIG. 4B depicts a 30 kV partial discharge insulation test platform.

[0042] FIG. 4C shows power electronic hardware and a photo of a manufactured prototype.

[0043] FIG. 4D shows the circuit diagram of a DC / AC converter.

[0044] FIG. 5A is a graph showing the medium frequency transformer (MFT) coupling coefficient, which was observed to decrease with the increase of the air gap.

[0045] FIG. 5B shows the electric field distribution under an applied voltage from a conducted study.

[0046] FIG. 5C shows the winding resistance measurement of a prototype planar MFT measured as a function of frequency.

[0047] FIG. 5D shows the pattern diagram of a partial discharge (PD test) for the prototype MFT.

[0048] The components in the drawings are not necessarily to scale relative to each other. Like reference, numerals designate corresponding parts throughout the several views.DETAILED DESCRIPTION

[0049] It is appreciated that certain features of the disclosure, which are, for clarity, described in the context of separate aspects, can also be provided in combination with a single aspect. Conversely, various features of the disclosure, which are, for brevity, described in the context of a single aspect, can also be provided separately or in any suitable sub-combination. Unless defined otherwise, all technical and scientific terms used herein have the same meaningas commonly understood by one of ordinary skill in the art. Methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure.

[0050] Example System

[0051] Fig. 1 shows an example planar matrix transformer 102 in accordance with an illustrative embodiment. The planar matrix transformer (also referred to herein as a planar tiled transformer or planar transformer) has a short height profile and large surface area that has strong heat dissipation capability in a low-profile configuration. The high heat dissipation capability facilitates high-density configurations and operations for the exemplary planar matrix transformer. In some implementations, the planar matrix transformer 102 has an aspect ratio (in the x- y- coordinate plane) between 5:1 and 10:1. In some embodiments, the aspect ratio can be greater than 10:1 or less than 5:1.

[0052] In the example shown in Fig. 1, a power electronic system 100 is shown that employs the planar matrix transformer 102 in connection between a first set of power electronic components 101a and a second set of power electronic components 101b. Diagrams 102’ and 102”, respectively, show a cross-sectional side view and an assembled view of an example configuration of the planar matrix transformer 102.

[0053] In the example shown in Fig. 1, the planar transformer 102 includes a set of conductors 104 (shown as a first conductor 104a, a second conductor 104b, a third conductor 104c, and a fourth conductor 104d) and a set of magnetic material tiles 106 (e.g., soft magnetic material tiles). In various examples, a conductor can comprise one or more windings or be a portion of a winding. The magnetic material tiles 106 can comprise ferrite or meta-ferrite material and can, in some examples, be used to direct or control an electric or magnetic field. In some implementations, the magnetic material tiles 106 are in contact with the set of conductors 104. Alternatively, the magnetic material tiles 106 can be separated from the conductors 104 by an intermediate material such as a gaseous substance (e.g., air gap), a liquid (e.g., oil), or solid (e.g., epoxy, silicon gel). The magnetic material tiles 106 (shown as 106a, 106b, 106c, 106d) form, in whole, or in part, a magnetic core shell in which the shell has a first portion (e.g., top portion) and a second portion (e.g., bottom portion) that house the set of planar conductors 104. In the example shown in Fig. 1, the magnetic material tiles 106 are embedded into a housing 108. In some embodiments, the magnetic material tiles 106 may be arranged in an array or matrix configuration. In some implementations, the magnetic material tiles 106 can be configured as a unitary body (e.g., a plate).

[0054] As depicted in Fig. 1, the conductors (e.g., 104a, 104b, 104c, 104d) are arranged in a planar configuration, correspondingly spaced apart (e.g., parallel adjacent) from each other and as pairs 105 a, 105b in which the first conductor 104a and third conductor 104c are connected to one another, and the second conductor 104b and fourth conductor 104d are connected to one another. The conductors can be configured as a cable having a conducting portion and an insulating portion. The two pairs are offset from one another through an air gap or dielectric material.

[0055] The transformer 102 includes a set of cables or bus bars 110 (shown as 110a, 110b) that connect conductors 104a, 104c and 104b, 104d to form the pairs 115a, 115b. The transformer 102 may include another set of cables or bus bars 112 (shown as 112a, 112b, 112c, 112d) to connect to terminals of the power electronic components 101a, 101b.

[0056] The power electronic components 101a, 101b may be configured as an AC-DC converter, a DC-AC converter, an AC-AC converter, a DC-DC converter, or other power electronic equipment for power conversion.

[0057] Example Planar Transformer Configurations

[0058] Figs. 2A-2F depict proposed planar transformer configurations in accordance with certain embodiments of the present disclosure.

[0059] Fig. 2A is an example configuration of a planar matrix transformer 102’ showing the pairs 105a, 105b of conductors 104a, 104c and 104c, 104d having an offset from each other.

[0060] Fig. 2B is an example configuration of a planar matrix transformer 102’ showing the pairs of conductors 104a, 104b and 104c, 104d being aligned in the same planar orientation and plane to one another.

[0061] Fig. 2C is an example configuration of a planar matrix transformer 102’ showing the pairs 105a, 105b of conductors 104a, 104c and 104b, 104b being formed to have an angled profile.

[0062] Fig. 2D is an example configuration of a planar matrix transformer 102’ having single conductors (104a, 104b) in a stacked configuration where the first conductor 104a is positioned directly above the second conductor 104b, i.e., the first conductor 104a is located at a top portion of the planar matrix transformer 102’ and the second conductor 104b is located at a bottom portion of the planar matrix transformer 102’.

[0063] Fig. 2E shows an example configuration of a planar matrix transformer 102’ in which each conductor 104a, 104b is encapsulated by unitary magnetic materials 106a, 106b (e.g., plates).

[0064] Fig. 2F shows another example configuration of a planar matrix transformer 102’ having single conductors 104a, 104b in a stacked configuration where the first conductor 104a is positioned directly above the second conductor 104b. As shown, the first conductor 104a is positioned in proximity to a first set or array of magnetic material tiles 106 (as shown, 106a, 106b, 106c) such that a center of the first conductor 104a surrounds the central tile of the first set or array of magnetic material tiles 106 (see also configuration 310e and 31 Of in Fig. 3 A, discussed below). In some embodiments, the device includes a tile that is placed in the center of the first conductor 104a. Said differently, a center of the first set or array of magnetic material tiles 106 is concentric with the first conductor 104a and the second conductor 104b. In other embodiments, there is no center tile. In the example shown in FIG. 2F, the planar matrix transformer 102 includes thermal conductors 220a, 220b configured to dissipate (e.g., absorb, extract) heat from the planar matrix transformer 102’. As shown, the first conductor 104a is in contact with a first thermal conductor 220a. As further depicted, the second conductor 104b is in proximity to a second set or array of magnetic material tiles 106 (as shown 106d, 106e, 106f) and is in contact with a second thermal conductor 220b. In some implementations, the thermal conductors 220 can comprise the same material as the magnetic material tiles 106 and may be part of the set or array of magnetic tiles 106.

[0065] Transformer Modular Configuration and Method of Fabrication

[0066] As discussed above, multiple planar conductors can have multiple sections, each formed of conductors arranged in a planar configuration. The multiple sections for each leg of the transformer can be standardized as a module, and connecting cables can be fixably attached to one of multiple available connecting points on a given conductor module to adjust the turns ratio and the turn configurations for the planar matrix transformer. The modular design can facilitate flexible applications of the planar matrix transformer for various applications.

[0067] Fig. 3 A shows different configurations of different turn ratios and turn configurations for the planar matrix transformer that can be established based on the connections between the multiple sections of the planar transformer winding, in accordance with various embodiments.

[0068] Fig. 3B shows a diagram 350 illustrating a method of fabricating and configuring the transformer 102 in accordance with certain implementations disclosed herein. The method 350 includes providing (352) a set of conductors, including a first conductor, second conductor, third conductor, and fourth conductor, each of the first conductor and second conductor being arranged in a pre-defmed configuration (e.g., planar configuration), the configuration of the first conductor and second conductor being correspondingly spaced apart (e.g., paralleladjacent) from each other, wherein the third conductor is connectable to the first conductor and is arranged in a third loop in a pre-defined configuration, wherein the fourth conductor is connectable to the second conductor and is arranged in a fourth loop in a pre-defined configuration, wherein the third loop has an area and the fourth loop has an area, the area of the third loop and the area of the fourth loop corresponding (e.g., parallel adjacent) to one another, and wherein the first conductor, second conductor, third conductor, and fourth conductor are placed in proximity to a set of two or more magnetic material tiles (e.g., that forms a magnetic core shell having a first portion and a second portion that house the set of planar conductors).

[0069] Method 350 then includes connecting (354) a first cable or bus bar between at a position of multiple available positions on the first conductor and a position of multiple available positions on the third conductor to establish a first winding configuration for the first conductor and the second conductor.

[0070] Method 350 then includes connecting (356) a second cable or bus bar between at a position of multiple available positions on the second conductor and a position of multiple available positions on the fourth conductor to establish a second winding configuration for the first conductor and the second conductor. The connected positions on the first, second, third, and fourth conductors can adjust at least one of the turn ratios and turn configurations for the transformer, as described below.

[0071] In the example shown in Figs. 3A and 3B, the four sets of conductors 104a, 104b, 104c, 104d are arranged as two sets of pairs 305 a, 305b. In Fig. 3 A, the first conductor 104a is laid out in a planar configuration with an output cable or connection 302 to an internal position in the winding, the second conductor 104b is laid out in a planar configuration with an output cable or connection 304 to an internal position in the winding, the third conductor 104c is laid out in a planar configuration with an input cable or connection 306 to an external position in the winding, and the fourth conductor 104d is laid out in a planar configuration with an input cable or connection 308 to an external position in the winding. It should be understood that the aspect ratios of the planar matrix transformer 102 (e.g., between 5:1 and 10:1) and the relative positions of the conductors / windings can be varied to provide different transformer configurations. Notably, the proposed configurations increase the overall surface area of the proposed devices, thereby increasing heat dissipation.

[0072] Configuration #1. Fig. 3A shows five configurations 310a, 310b, 310c, 3 lOd, 3 lOe, and 310f. In the first configuration 310a, the first pair 305a includes a first cable 312 that connects (i) to the input 306 of conductor 104c located at the outer position of the winding and(ii) to the outer position of the conductor 104a that then winds to the inner position to exit at output 302, and a second cable 314 that connects (i) to the inner position of the conductor 104c and (ii) to the inner position of the conductor 104a having the output 302. This forms a parallel circuit. The second pair 305b includes a first cable 316 that connects (i) to the input 308 of conductor 104d located at the outer position of the winding and (ii) to the outer position of the conductor 104b that then winds to the inner position to exit at output 304, and a second cable 318 that connects (i) to the inner position of the conductor 104d and (ii) to the inner position of the conductor 104b having the output 304. It can be observed that the configuration are identical to one another and, thus, configuration #1 provides a 1 : 1 turns ratio formed between two identical parallel windings.

[0073] Configuration #2. In the second configuration 310b, the first pair 305a includes a single cable 320 that connects (i) to the inner position of conductor 104c, which winds to the input 306, and (ii) to the outer position of the conductor 104a that then winds to the inner position to exit at output 302. This forms a series circuit. The second pair 305b includes a single cable 322 that connects (i) to the inner position of conductor 104d, which winds to the input 308 and (ii) to the outer position of the conductor 104b that then winds to the inner position to exit at output 304. This also forms a series circuit. It can be observed that the configurations are identical to one another and, thus, configuration #2 provides a 2:2 turns ratio formed between two identical series-winding pairs across the two sets of conductors.

[0074] Configuration #3. In the third configuration 310c, the first pair 305a includes a single cable 320 that connects (i) to the inner position of conductor 104c, which winds to the input 306 and (ii) to the outer position of the conductor 104a that then winds to the inner position to exit at output 302. This forms a series circuit. The second pair 305b includes a first cable 316 that connects (i) to the input 308 of conductor 104d located at the outer position of the winding and (ii) to the outer position of the conductor 104b that then winds to the inner position to exit at output 304, and a second cable 318 that connects (i) to the inner position of the conductor 104d and (ii) to the inner position of the conductor 104b having the output 304. This forms a parallel circuit. It can be observed that the configurations are different from one another and, thus, configuration #3 provides a 1 :2 turns ratio formed between a series pair and a parallel pair of conductors.

[0075] Configuration #4. In the fourth configuration 310d, the first pair 305a includes a first cable 312 that connects (i) to the input 306 of conductor 104c located at the outer position of the winding and (ii) to the outer position of the conductor 104a that then winds to the inner position to exit at output 302, and a second cable 314 that connects (i) to the inner position ofthe conductor 104c and (ii) to the inner position of the conductor 104a having the output 302. This forms a parallel circuit. The second pair 305b includes a single cable 322 that connects (i) to the inner position of conductor 104d, which winds to the input 308, and (ii) to the outer position of the conductor 104b that then winds to the inner position to exit at output 304. This also forms a series circuit. It can be observed that the configurations are different from one another and, thus, configuration #4 provides a 2: 1 turns ratio formed between a series pair and a parallel pair of conductors.

[0076] Configuration #5. In the fifth configuration 310e, the example planar matrix transformer 102 comprises a single (e.g., upper) first conductor 305a and a single (e.g., lower) second conductor 305b that are positioned in parallel to one another. Each conductor 305a, 305b is positioned in proximity to a respective magnetic material tile array or set 214 such that a center of conductor 305a, 305b surrounds the central tile of the magnetic material tile array or set 214 (in other words a center of the magnetic material tile array or set 214 is concentric with each conductor 305a, 305b). Configuration #5 provides a 1 : 1 turns ratio formed between single or unitary conductors.

[0077] Configuration #6. In the sixth configuration 31 Of, the planar matrix transformer 102 comprises a first and second conductor 305a, 305b. Similar to the fifth configuration, each conductor 305a, 305b is positioned in proximity to a respective magnetic material tile array or set 214 such that a center of conductor 305a, 305b surrounds the central tile of the magnetic material tile array or set 214. Configuration #6 also provides a 1 : 1 turns ratio formed between single or unitary conductors. The sixth configuration 31 Of further includes a plurality of thermal conductors 220 positioned adjacent to the magnetic material tiles of the array 214 each located at a respective corner / edge of the planar transformer 102. In some implementations, the thermal conductors 220 are coplanar with the magnetic material tiles 214 or may be located in a different plane (e.g., above or below).

[0078] It is contemplated that the cables or bus bars (e.g., 312, 314, 316, 318, 320, 322) are connectable to other positions on the conductors 104a, 104b, 104c, and 104d. To this end, the effective turn ratio between the two pairs of conductors 104a, 104b, 104c, and 104d can be adjusted accordingly, e.g., 20: 1, 19: 1, 18: 1, 17: 1, 16: 1, 15: 1, 14: 1, 13: 1, 12: 1, 11 : 1, 10: 1, 9: 1, 8: 1, 7:1, 6: 1, 5: 1, 4: 1, 3: 1, 2: 1, 1 : 1, 20:2, 19:2, 18:2, 17:2, 16:2, 15:2, 14:2, 13:2, 12:2, 11 :2,10:2, 9:2, 8:2, 7:2, 6:2, 5:2, 4:2, 3:2, 2:2, 1 :2, 20:3, 19:3, 18:3, 17:3, 16:3, 15:3, 14:3, 13:3,12:3, 11 :3, 10:3, 9:3, 8:3, 7:3, 6:3, 5:3, 4:3, 3:3, 2:3, 1 :3, 20:4, 19:4, 18:4, 17:4, 16:4, 15:4,14:4, 13:4, 12:4, 11 :4, 10:4, 9:4, 8:4, 7:4, 6:4, 5:4, 4:4, 3:4, 2:4, 1 :4, 20:5, 19:5, 18:5, 17:5,16:5, 15:5, 14:5, 13:5, 12:5, 11 :5, 10:5, 9:5, 8:5, 7:5, 6:5, 5:5, 4:5, 3:5, 2:5, 1 :5, 20:6, 19:6,18:6, 17:6, 16:6, 15:6, 14:6, 13:6, 12:6, 11:6, 10:6, 9:6, 8:6, 7:6, 6:6, 5:6, 4:6, 3:6, 2:6, 1:6, 20:7, 19:7, 18:7, 17:7, 16:7, 15:7, 14:7, 13:7, 12:7, 11:7, 10:7, 9:7, 8:7, 7:7, 6:7, 5:7, 4:7, 3:7, 2:7, 1:7, 20:8, 19:8, 18:8, 17:8, 16:8, 15:8, 14:8, 13:8, 12:8, 11:8, 10:8, 9:8, 8:8, 7:8, 6:8, 5:8, 4:8, 3:8, 2:8, 1:8, 20:9, 19:9, 18:9, 17:9, 16:9, 15:9, 14:9, 13:9, 12:9, 11:9, 10:9, 9:9, 8:9, 7:9, 6:9, 5:9, 4:9, 3:9, 2:9, 1:9, 20:10, 19:10, 18:10, 17:10, 16:10, 15:10, 14:10, 13:10, 12:10, 11:10, 10:10, 9:10, 8:10, 7:10, 6:10, 5:10, 4:10, 3:10, 2:10, 1:10, 20:11, 19:11, 18:11, 17:11, 16:11, 15:11, 14:11, 13:11, 12:11, 11:11, 10:11, 9:11, 8:11, 7:11, 6:11, 5:11, 4:11, 3:11, 2:11, 1:11, 20:12, 19:12, 18:12, 17:12, 16:12, 15:12, 14:12, 13:12, 12:12, 11:12, 10:12, 9:12, 8:12, 7:12, 6:12,5:12,4:12,3:12,2:12, 1:12, 20:13, 19:13, 18:13, 17:13, 16:13, 15:13, 14:13, 13:13, 12:13, 11:13, 10:13, 9:13, 8:13, 7:13, 6:13, 5:13, 4:13, 3:13, 2:13, 1:13, 20:14, 19:14, 18:14, 17:14, 16:14, 15:14, 14:14, 13:14, 12:14, 11:14, 10:14, 9:14, 8:14, 7:14, 6:14, 5:14, 4:14, 3:14, 2:14, 1:14, 20:15, 19:15, 18:15, 17:15, 16:15, 15:15, 14:15, 13:15, 12:15, 11:15, 10:15, 9:15, 8:15, 7:15,6:15,5:15,4:15,3:15,2:15, 1:15,20:16, 19:16, 18:16, 17:16, 16:16, 15:16, 14:16, 13:16, 12:16, 11:16, 10:16, 9:16, 8:16, 7:16, 6:16, 5:16, 4:16, 3:16, 2:16, 1:16, 20:17, 19:17, 18:17, 17:17, 16:17, 15:17, 14:17, 13:17, 12:17, 11:17, 10:17, 9:17, 8:17, 7:17, 6:17, 5:17, 4:17, 3:17, 2:17, 1:17, 20:18, 19:18, 18:18, 17:18, 16:18, 15:18, 14:18, 13:18, 12:18, 11:18, 10:18, 9:18, 8:18, 7:18, 6:18, 5:18, 4:18, 3:18, 2:18, 1:18, 20:19, 19:19, 18:19, 17:19, 16:19, 15:19, 14:19, 13:19, 12:19, 11:19, 10:19, 9:19, 8:19, 7:19, 6:19, 5:19, 4:19, 3:19, 2:19, 1:19, 20:20, 19:20, 18:20, 17:20, 16:20, 15:20, 14:20, 13:20, 12:20, 11:20, 10:20, 9:20, 8:20, 7:20, 6:20, 5:20, 4:20, 3:20, 2:20, 1:20. Other configurations may be employed.

[0079] Indeed, in some embodiments, the first and third conductors can be arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor in which the second and fourth conductors are arranged in series configuration based on a second set of connection points located on the second and the fourth conductors.

[0080] The first and third conductors can be arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor in which the second and fourth conductors are arranged in a series configuration based on a second set of connection points located on the second and the fourth conductors.

[0081] The first and third conductors can be arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, in which the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

[0082] The first and third conductors can be arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor in which the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

[0083] Experimental Results and Additional Examples

[0084] A study was conducted to develop and evaluate a planar matrix transformer, e.g., as described in relation to Fig. 1. For the study, a design was developed for a compact high- power medium frequency transformer (MFT). High voltage insulation and thermal management are among the challenges in a compact high-power medium frequency transformer (MFT) design.

[0085] The study developed a magnetic building block design that can integrate the planar and matrix transformer topologies for a high-power MFT device. The developed planar transformer exhibits reduced height and larger surface area compared to conventional MFT devices that additionally improve heat dissipation capability. By integrating the matrix transformer concept, different types of turns ratio are available by changing the internal connections.

[0086] Prototype System. Figs. 4A shows a CAD model of the 200-kW planar matrix MFT. Table I shows the specification for the 200-kW planar matrix MFT developed in the study. Fig. 4C and Fig. 4D show a CLLC-based DC / AC converter that employs the 200-kW planar matrix MFT in an interleaved bidirectional three-level buck / boost DC / AC inverter that is followed by an uncontrolled high-frequency resonant converter. With the three-level topology, the DC side can support 1500V PV farm operation while the output side can safely generate a peak voltage of 1600V. Two MFTs were designed to provide galvanic isolation with a 1 : 1 turn ratio. This design employed two MFTs. Fig. 4C shows the power electronic hardware and a photo of a manufactured prototype. Fig. 4D shows the circuit diagram of the DC / AC converter.Table I. Modular converter specification.

[0087] In Fig. 4A, the structure and winding layout of the planar matrix transformer developed in the study is shown. The planar matrix transformer 200 includes a first planarconductor 202 (shown as “Primary Windings” 202) that includes a first coil 204 and a second coil 206, and a second planar conductor 208 (shown as “Secondary Windings” 208) that includes a third coil 210 and a fourth coil 212. The planar matrix transformer 200 was designed to transform a DC input (900V - 1500V) to an AC output (1131 Vrms). The system links together the first planar conductor 202 and the second planar conductor 208 through a common oscillating magnetic circuit. The planar matrix transformer operates on the electromagnetic principle of mutual induction by which a coil of wire magnetically induces a voltage into another coil located in close proximity to it. The first planar conductor 202 and the second planar conductor 208 are electrically isolated from each other but are magnetically linked, allowing electrical power to be transferred from one conductor to the other. When an electric current is passed through the first planar conductor 202, a magnetic field is developed, which induces a voltage into the second planar conductor 208.

[0088] Embodiments of the present disclosure provide for thermal management of the proposed planar matrix transformers. As further depicted in FIG. 4A, the planar matrix transformer 102 comprises one or more thermal conductors 220, shown as first set 220a and second set 220b located on an upper portion and lower portion of the planar matrix transformer 102, respectively, and positioned between the sets of magnetic tiles 214.

[0089] Fig. 5C shows the magnetic flux within the planar matrix transformer. The difference in voltage between the first planar conductor 202 and the second planar conductor 208 is determined by the number of turns (i.e., loops) in the first planar conductor compared to the number of turns (i.e., loops) in the second planar conductor according to Faraday’s Law. The ratio of the number of turns in the first planar conductor to the number of turns in the second planar conductor (i.e., the turns ratio) will be the same as the ratio between the input voltage and the output voltage.

[0090] The first coil 204 and the second coil 206 are each made from a wire arranged in a planar spiral configuration such that it forms a set of adjacent repeating loops of varying loop profiles (i.e., of varying loop diameter). In some embodiments, the set of repeating loops may be nonadj acent. In other embodiments, the nonadj acent loops can have a distance between loops of from about 1 mm to about 10 mm (e.g., about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, and about 9 mm). The outermost diameter of the first coil can be from about 100 mm to about 500 mm. The third coil 210 and fourth coil 212 are also similarly configured with a wire arranged in a planar spiral configuration such that it forms a set of adjacent repeating loops of varying loop profiles. The first coil 204 partiallyoverlaps the second coil 206 (similar to the third and fourth coil 210, 212 to decrease whole volume and winding loss with flux cancelation.

[0091] Each of the first wire, the second wire, the third wire, and the fourth wire was made of a ductile and electrically conductive material to facilitate the flow of electrical charge along the length of the wire. It was contemplated that copper, iron, aluminum, silver, gold, or other acceptable ductile electrical conductors or alloys or combinations thereof could be used. It was contemplated that the first wire, the second wire, the third wire, and the fourth wire could be made of the same material or different materials. It was contemplated that the first wire, the second wire, the third wire, and the fourth wire can have a diameter of from about 5 AWG to about 30 AWG, including exemplary values of about 6 AWG, about 7 AWG, about 8 AWG, about 9 AWG, about 10 AWG, about 12 AWG, about 14 AWG, about 16 AWG, about 18 AWG, about 20 AWG, about 22 AWG, about 24 AWG, about 26 AWG, and about 28 AWG.

[0092] In the example of Fig. 4A, the planar matrix transformer 102, the first planar conductor 202 is separated from the second planar conductor by an air gap. The split structure can be more flexible for insulation design. It was contemplated that the airgap can have a width of from 0.1 mm to 10 mm (e.g., 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.25 mm, 1.5 mm, 1.75 mm, 2 mm, 2.5 mm, 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm, 5.5. mm, 6 mm, 6.5 mm, 7 mm, 7.5 mm, 8 mm, 8.5 mm, 9 mm, and 9.5 mm). Indeed, the airgap can have a width of 10 mm and / or be selected based on the coupling coefficient and insulation voltage.

[0093] The first planar conductor 202a is positioned in proximity to a first set of one or more permanent magnets 214 (shown as “Primary Ferrite Tiles”). The first set of one or more permanent magnets includes 12 total rectangular magnets arranged in a tile configuration. It was contemplated that the first and / or second sets of one or more permanent magnets can include from 2 to 20 rectangular magnets(e.g., 4 rectangular magnets, 6 rectangular magnets, 8 rectangular magnets, 10 rectangular magnets, 12 rectangular magnets, 14 rectangular magnets, 16 rectangular magnets, and 18 rectangular magnets). Other shapes were also considered, including triangular, square, pentagonal, hexagonal, heptagonal, octagonal, nonagonal, elliptical, star-shaped, t-shaped, x-shaped, or any combinations thereof such that the magnets can be configured in a matrix or tile configuration. In the prototype, the first set of one or more permanent magnets 214 was made of low-loss FPL100 / 100 / 6-BH1T, the magnetic material having low-loss characteristics in the broader temperature range. It was contemplated that permanent magnets could be made of iron, steel, nickel, cobalt, rare-earth metals, or alloysor combinations thereof. The second set of one or more permanent magnets 216 is parallel and corresponds to the first set of one or more permanent magnets 214.

[0094] In Fig. 4A, the first set of one or more permanent magnets 214 and second planar conductor 208a are positioned in proximity to a second set of one or more permanent magnets 216 (shown as “Secondary Ferrite Tiles”) are each configured in a tile configuration to enclose, in part, the first planar conductor 202 and the second planar conductor 208. A first set of ferrite tiles / bars 214a are included at the edges of the matrix of the first set of one or more permanent magnets such that the ferrite bars extend at least partially along the thickness of the first planar conductor 202 (e.g., as a casing) to improve magnetic coupling and provide shielding. The height of the first set of ferrite bars was established between about 10 mm to about 70 mm to change the magnetizing / leakage inductance. Additionally, as shown, one or more cables (222a, 222b, 224a, 224b) are included.

[0095] Test System. Fig. 4B shows the measurement and test system capable of a 30kV PD test employed to test the 200-kW planar matrix MFT. The test system was developed based on IEC 60270 [5], In Fig. 4B, the test system was configured to acquire winding resistance measurement value using a Hioki IM3536 LCR meter up to 1 MHz. The MFT power density was measured at 27.2 kW / L. The system efficiency at 200 kW was estimated at 99.75%. The study adopted an HV partial discharge (PD) insulation test platform to perform the insulation test.

[0096] Test Results. The 200 kW MFT developed in the study was observed to achieve 27.2 kW / L power density and an estimated 99.75 % efficiency at full power.

[0097] Fig. 5A shows the MFT coupling coefficient, which was observed to decrease with the increase of the air gap.

[0098] Fig. 5B shows the electric field distribution under an applied voltage 10 kV with 5 mm air gap. The maximum insulation voltage was limited by the air breakdown electric field of 2.5-3 kV / mm. The magnetic building block insulation capability could be potted with epoxy.

[0099] Fig. 5C shows the winding resistance measurement of the prototype planar MFT measured as a function of frequency.

[0100] Fig. 5D shows the pattern diagram of the PD test for the MFT. The PD was induced when the applied voltage increased to an 8 kV peak. Fig. 5D shows the partial discharge insulation test at 60 Hz 8 kV ac peak voltage.

[0101] Discussion

[0102] Medium voltage solid-state transformers (SST) have been widely studied as the next-generation technology for many medium voltage (MV) applications such as smartdistribution systems, traction systems, renewable energy systems, and ultra-fast electric vehicle (EV) chargers [1], [2], Power electronics modular design is a key technology for SST to achieve medium voltage and high-power density. Medium frequency transformer (MFT) is the key component needed to process high power and provide high insulation capability. For high- power MFTs, the design must also consider the tradeoffs among the competing objectives, including reliable electrical insulation, high efficiency, high power density, and superior thermal performance [3],

[0103] The study discussed herein developed a 200 kW planar magnetic building block design for a medium voltage solid state transformer. The planar design exhibits reduced height (low profile) and larger surface area, resulting in improved heat dissipation capability [4], By integrating the matrix transformer concept, four different types of connections are available by changing the internal connections. The planar and matrix transformer design configurations were integrated to achieve hundreds of kW MFT designs. The MFTs prototype has been preliminary tested with a partial discharge insulation test.

[0104] In this specification and in the claims that follow, reference will be made to a number of terms, which shall be defined to have the following meanings:

[0105] Throughout the description and claims of this specification, the word “comprise” and other forms of the word, such as “comprising” and “comprises,” means including but not limited to, and are not intended to exclude, for example, other additives, segments, integers, or steps. Furthermore, it is to be understood that the terms comprise, comprising, and comprises as they relate to various aspects, elements, and features of the disclosed invention also include the more limited aspects of “consisting essentially of’ and “consisting of.”

[0106] As used herein, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to a “polymer” includes aspects having two or more such polymers unless the context clearly indicates otherwise.

[0107] Ranges can be expressed herein as from “about” one particular value and / or to “about” another particular value. When such a range is expressed, another aspect includes from the one particular value and / or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another aspect. It should be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0108] As used herein, the terms “optional” or “optionally” mean that the subsequently described event or circumstance may or may not occur, and that the description includes instances where said event or circumstance occurs and instances where it does not.

[0109] For the terms "for example" and "such as," and grammatical equivalences thereof, the phrase "and without limitation" is understood to follow unless explicitly stated otherwise.

[0110] The following patents, applications and publications as listed below and throughout this document are hereby incorporated by reference in their entirety herein.[1] A. Q. Huang, "Medium-Voltage Solid-State Transformer: Technology for a Smarter and Resilient Grid," in IEEE Industrial Electronics Magazine, vol. 10, no. 3, pp. 29-42, Sept.2016, doi: 10.1109 / MIE.2016.2589061.[2] W. Xu, Z. Guo, A. Vetrivelan, R. Yu and A. Q. Huang, "Hardware Design of a 13.8kV / 3MVA PV Plus Storage Solid State Transformer (PVS-SST)," in IEEE Journal of Emerging and Selected Topics in Power Electronics.[3] Z. Guo, R. Yu, W. Xu, X. Feng and A. Q. Huang, "Design and Optimization of a 200-kW Medium -Frequency Transformer for Medium- Voltage SiC PV Inverters," in IEEE Transactions on Power Electronics, vol. 36, no. 9, pp. 10548-10560, Sept. 2021, doi:10.1109 / TPEL.2021.3059879.[4] M. Fu, C. Fei, Y. Yang, Q. Li and F. C. Lee, "Optimal Design of Planar Magnetic Components for a Two-Stage GaN-Based DC-DC Converter," in IEEE Transactions on Power Electronics, vol. 34, no. 4, pp. 3329-3338, April 2019, doi:10.1109 / TPEL.2018.2849741.[5] IEC 60270:7000: High-voltage test techniques - Partial discharge measurements.

Claims

What is claimed is:

1. A system comprising: a planar transformer comprising: a set of conductors, including a first conductor and second conductor, each of the first conductor and second conductor being arranged in a planar or stacked configuration; and a set of two or more magnetic material tiles that forms a magnetic core shell having a first portion and a second portion that houses the set of planar or stacked conductors, wherein the first conductor is positioned in the first portion and second conductor is positioned in the second portion.

2. The system of claim 1, wherein the first conductor and second conductor are arranged in the planar configuration and are correspondingly spaced apart from each other.

3. The system of claim 1, wherein the first conductor and second conductor are arranged in the stacked configuration, and wherein the first conductor defines at least a portion of a first winding, and the second conductor defines at least a portion of a second winding.

4. The system of claim 1, wherein the set of two of more magnetic material tiles comprises one or more arrays of magnetic material tiles each having a center tile, wherein each center tile is concentric with the first conductor and second conductor.

5. The system of any one of claims 1-4, wherein the planar transformer further comprises one or more thermal conductors.

6. The system of claim 1, wherein the first planar conductor is arranged in a first loop in the planar configuration, wherein the second planar conductor is arranged in a second loop in the planar configuration, wherein the first loop has an area and the second loop has an area, the area of the first loop and the area of the second loop corresponding to one another.

7. The system of claim 6, wherein the set of conductors includes a third conductor and fourth conductor, wherein the third conductor is connected to the first planar conductor and isarranged in a third loop in the planar configuration, wherein the fourth planar conductor is connected to the second conductor and is arranged in a fourth loop in the planar configuration, wherein the third loop has an area, and the fourth loop has an area, the area of the third loop and the area of the fourth loop corresponding to one another.

8. The system of any one of claims 1-7, wherein the set of two or more magnetic material tiles includes (i) a first set of soft magnetic tiles arranged as tiles in the first portion of the magnetic core shell and (ii) a second set of soft magnetic tiles arranged as tiles in the second portion of the magnetic core shell.

9. The system of any one of claims 1-8, wherein the set of conductors are arranged in multiple sections as a module, the planar transformer including: a set connecting cables to fixably attach to one of multiple available connecting points on a given conductor module to adjust turn ratios and turn configurations for the planar transformer.

10. The system of claim 7, wherein the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, and wherein the second and fourth conductors are arranged in series configuration based on a second set of connection points located on the second and the fourth conductors.

11. The system of claim 7, wherein the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, and wherein the second and fourth conductors are arranged in series configuration based on a second set of connection points located on the second and the fourth conductors.

12. The system of claim 7, wherein the first and third conductors are arranged in a series configuration based on a third set of connection points located on the third conductor and the fourth conductor, and wherein the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

13. The system of claim 7, wherein the first and third conductors are arranged in a parallel configuration based on a first set of connection points located on the third conductor and the fourth conductor, and wherein the second and fourth conductors are arranged in parallel configuration based on a fourth set of connection points located on the second and the fourth conductors.

14. The system of any one of claims 1-13, wherein the set of conductors are encased in epoxy or polymer.

15. The system of any one of claims 1-13, wherein the conductors and magnetic shell are encased in epoxy or polymer, or in dielectric liquid material16. The system of any one of claims 1-15 further comprising: a second planar transformer comprising: a set of conductors, including a first conductor and second conductor, each of the first conductor and second conductor being arranged in a planar or stacked configuration; and a set of two or more magnetic material tiles that forms a magnetic core shell having a first portion and a second portion that house the set of planar or stacked conductors, including the first conductor and second conductor, wherein the second planar transformer is arranged in a parallel configuration relative to the planar transformer.

17. The system of any one of claims 7-16, wherein the first conductor is arranged in the planar configuration along a first plane, wherein the third conductor is arranged in the planar configuration along a second plane, wherein the first plane and second plane are parallel to one another.

18. A method of fabricating a transformer comprising: providing a set of conductors, including a first conductor, second conductor, third conductor, and fourth conductor, each of the first conductor and second conductor being arranged in a pre-defined configuration, the configuration of the first conductor and second conductor being correspondingly spaced apart from each other, wherein the third conductor is connectable to the first conductor and is arranged in a third loop in a pre-definedconfiguration, wherein the fourth conductor is connectable to the second conductor and is arranged in a fourth loop in a pre-defined configuration, wherein the third loop has an area and the fourth loop has an area, the area of the third loop and the area of the fourth loop corresponding to one another, and wherein the first conductor, second conductor, third conductor, and fourth conductor are placed in proximity to a set of two or more magnetic material tiles; connecting a first cable or bus bar between a position of multiple available positions on the first conductor and a position of multiple available positions on the third conductor to establish a first winding configuration for the first conductor and the second conductor; and connecting a second cable or bus bar between a position of multiple available positions on the second conductor and a position of multiple available positions on the fourth conductor to establish a second winding configuration for the first conductor and the second conductor, wherein the connected positions on the first, second, third, and fourth conductors adjust at least one of turn ratios and turn configurations for the transformer.

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