A quadrature flux core structure for increasing power density of a sigma converter

Abstract

The application discloses a kind of orthogonal flux magnetic core structures for improving Sigma converter power density, comprising: multiple magnetic legs, multiple PCB boards nested on the magnetic leg, the winding of Buck inductance, the first primary winding and the second primary winding of LLC transformer;First primary winding and second primary winding are respectively arranged in first PCB board and third PCB board, and the winding of Buck inductance is arranged in second PCB board;The leakage inductance of LLC transformer is used to replace the resonant inductance of LLC transformer, the magnetic flux loop generated by first primary winding and second primary winding is the same, and the magnetic flux loop generated by the winding of Buck inductance is orthogonal.This application integrates three magnetic elements using a magnetic core structure, reduces the volume occupied by magnetic elements, and is beneficial to improve Sigma converter power density.In addition, it also makes the coupling coefficient of first primary winding, second primary winding and the winding of Buck inductance all 0.

Description

Technical Field

[0001] The invention belongs to the technical field of Sigma converters, and in particular relates to an orthogonal magnetic flux core structure for improving the power density of a Sigma converter. Background Art

[0002] Currently, as data center load requirements continue to increase, power consumption is also increasing, driving the development of switching power converters towards higher power density and higher efficiency. Traditional data centers typically use a 12V bus, which results in significant power distribution losses. Therefore, Google proposed increasing the bus voltage to 48V to reduce losses. Subsequently, various 48V voltage-regulated power supplies emerged, with Sigma converters standing out due to their higher efficiency.

[0003] The Sigma converter is a quasi-parallel converter that connects an LLC topology and a buck converter (BUCK) topology in parallel via capacitors. The LLC is an isolated converter designed for high power, while the buck converter is a non-isolated converter designed for output voltage regulation. While the Sigma converter offers high efficiency, it contains three magnetic components (the LLC transformer and resonant inductor, and the buck circuit inductor). This results in a larger size and lower power density.

[0004] In order to improve the power density, the existing technology starts from the integration of the magnetic components of the Sigma converter. By using magnetic integration technology, the two magnetic components of the LLC transformer and resonant inductor are integrated into a magnetic core, which reduces the volume occupied by the magnetic components to a certain extent.

[0005] However, although the existing technology has improved the power density to a certain extent, there are still two magnetic cores after integration, and the volume is still relatively large. Summary of the Invention

[0006] In order to solve the above problems existing in the prior art, the present invention provides an orthogonal flux core structure for improving the power density of a Sigma converter. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0007] The present invention provides an orthogonal flux core structure for improving the power density of a Sigma converter, comprising: a plurality of magnetic legs, a plurality of PCB boards nested on the magnetic legs, a winding of a Buck inductor, a first primary winding and a second primary winding of an LLC transformer;

[0008] The multiple PCB boards include a first PCB board, a second PCB board, and a third PCB board, and the second PCB board is located between the first PCB board and the third PCB board; the first primary winding and the second primary winding are respectively arranged on the first PCB board and the third PCB board, and the winding of the Buck inductor is arranged on the second PCB board; wherein the leakage inductance of the LLC transformer is used to replace the resonant inductor of the LLC transformer, and the magnetic flux loop generated by the first primary winding and the second primary winding is the same and is orthogonal to the magnetic flux loop generated by the winding of the Buck inductor.

[0009] In one embodiment of the present invention, the magnetic core structure includes a first magnetic leg, a second magnetic leg, a third magnetic leg and a fourth magnetic leg, and the first PCB board, the second PCB board and the third PCB board each include four through holes and are nested on the first magnetic leg, the second magnetic leg, the third magnetic leg and the fourth magnetic leg through the four through holes.

[0010] In one embodiment of the present invention, the first primary winding includes a first sub-winding surrounding the first magnetic leg, the head end of which is connected to the resonant capacitor of the LLC transformer, and the second primary winding includes a second sub-winding surrounding the first magnetic leg; wherein,

[0011] The first sub-winding surrounds the first magnetic leg counterclockwise from outside to inside, and its end is connected to the head end of the second sub-winding through a first via hole. The second sub-winding surrounds the first magnetic leg counterclockwise from inside to outside.

[0012] In one embodiment of the present invention, the second primary winding includes a third sub-winding surrounding the second magnetic leg, the head end of which is connected to the end of the second sub-winding, and the first primary winding includes a fourth sub-winding surrounding the second magnetic leg; wherein,

[0013] The third sub-winding surrounds the second magnetic leg counterclockwise from outside to inside, and its end is connected to the head end of the fourth sub-winding through a second via hole. The fourth sub-winding surrounds the second magnetic leg counterclockwise from inside to outside.

[0014] In one embodiment of the present invention, the first primary winding includes a fifth sub-winding surrounding the third magnetic leg, the head end of which is connected to the end of the fourth sub-winding, and the second primary winding includes a sixth sub-winding surrounding the third magnetic leg; wherein,

[0015] The fifth sub-winding surrounds the third magnetic leg clockwise from outside to inside, and its end is connected to the head end of the sixth sub-winding through a third via hole. The sixth sub-winding surrounds the third magnetic leg clockwise from inside to outside.

[0016] In one embodiment of the present invention, the second primary winding includes a seventh sub-winding surrounding the fourth magnetic leg, the head end of which is connected to the end of the sixth sub-winding, and the first primary winding includes an eighth sub-winding surrounding the fourth magnetic leg; wherein,

[0017] The seventh sub-winding surrounds the fourth magnetic leg counterclockwise from the inside to the outside, and its end is connected to the head end of the eighth sub-winding through the fourth via hole. The eighth sub-winding surrounds the fourth magnetic leg clockwise from the inside to the outside, and its end is grounded.

[0018] In one embodiment of the present invention, in a direction perpendicular to the plane where the second PCB board is located, the orthographic projection of the winding of the Buck inductor is S-shaped.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The present invention provides an orthogonal magnetic flux core structure for improving the power density of a Sigma converter. The structure comprises a first PCB board, a second PCB board, and a third PCB board, all of which are nested on magnetic legs via through holes. The second PCB board is located between the first and third PCB boards. A first primary winding and a second primary winding are respectively arranged on the first and third PCB boards. The winding of a Buck inductor is arranged on the second PCB board. Since the leakage inductance of an LLC transformer can replace the resonant inductor of the LLC transformer, the present invention integrates the three magnetic components of the LLC transformer, the resonant inductor, and the Buck inductor in the Sigma converter using a single magnetic core structure, thereby further reducing the volume occupied by the magnetic components and facilitating improved power density of the Sigma converter.

[0021] In addition, since the magnetic flux loops generated by the first primary winding and the second primary winding are orthogonal to the magnetic flux loop generated by the winding of the Buck inductor, the coupling coefficient between the first primary winding and the winding of the Buck inductor can be made 0, and the coupling coefficient between the second primary winding and the winding of the Buck inductor can also be made 0.

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a topological structure diagram of a Sigma converter in related art;

[0024] Figure 2 Schematic diagram of an orthogonal flux core structure for improving the power density of a Sigma converter provided by an embodiment of the present invention;

[0025] Figure 3 is a schematic diagram of a first primary winding provided by an embodiment of the present invention;

[0026] Figure 4 is a schematic diagram of a second primary winding provided by an embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of a magnetic flux loop generated by a first primary winding and a second primary winding provided by an embodiment of the present invention;

[0028] Figure 6 is another schematic diagram of a magnetic flux loop generated by a first primary winding and a second primary winding provided by an embodiment of the present invention;

[0029] Figure 7 Schematic diagram of a winding of a Buck inductor provided in an embodiment of the present invention;

[0030] Figure 8 This is a schematic diagram of a magnetic flux loop generated by a Buck inductor provided in an embodiment of the present invention;

[0031] Figure 9 is another schematic diagram of a magnetic flux loop generated by a Buck inductor provided in an embodiment of the present invention;

[0032] Figure 10 is another schematic diagram of the first primary winding provided by an embodiment of the present invention;

[0033] Figure 11 is another schematic diagram of the second primary winding provided by an embodiment of the present invention;

[0034] Figure 12 1 is another schematic diagram of the winding of a Buck inductor provided in an embodiment of the present invention;

[0035] Figure 13 1 is a diagram of simulation results provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described in detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto.

[0037] Figure 1 This is a topological diagram of the Sigma converter in related technology. Figure 1 Sigma converter is a quasi-parallel converter that uses capacitor V in The LLC topology is connected in parallel with the BUCK topology. To improve power density, the related art uses the leakage inductance of the LLC transformer to replace the resonant inductor. This is equivalent to integrating the LLC transformer and the LLC resonant inductor into the same magnetic core, eliminating the need for a core, thus reducing the size of the Sigma converter and increasing power density.

[0038] However, after integration in the above manner, there are still two magnetic cores, and the volume is still relatively large.

[0039] In view of this, an embodiment of the present invention provides an orthogonal flux core structure for improving the power density of a Sigma converter.

[0040] Figure 2 Schematic diagram of an orthogonal flux core structure for improving the power density of a Sigma converter provided by an embodiment of the present invention. Figure 3 is a schematic diagram of a first primary winding provided by an embodiment of the present invention, Figure 4 : is a schematic diagram of the second primary winding provided by an embodiment of the present invention. Figure 2-4 As shown, an embodiment of the present invention provides an orthogonal flux core structure for improving the power density of a Sigma converter, comprising: a plurality of magnetic legs 10, a plurality of PCB boards 20 nested on the magnetic legs 10, a winding 30 of a Buck inductor, a first primary winding 40 and a second primary winding 50 of an LLC transformer;

[0041] The multiple PCB boards 20 include a first PCB board 201, a second PCB board 202, and a third PCB board 203, with the second PCB board 202 located between the first PCB board 201 and the third PCB board 203. The first primary winding 40 and the second primary winding 50 are respectively arranged on the first PCB board 201 and the third PCB board 203, and the winding 30 of the Buck inductor is arranged on the second PCB board 202. The leakage inductance of the LLC transformer is used to replace the resonant inductance of the LLC transformer. The magnetic flux loops generated by the first primary winding 40 and the second primary winding 50 are the same and are both orthogonal to the magnetic flux loop generated by the winding 30 of the Buck inductor.

[0042] Specifically, the magnetic core structure includes multiple magnetic legs 10, multiple PCB boards 20, a buck inductor winding 30, and first and second primary windings 40 and 50 of an LLC transformer. The multiple PCB boards 20 include a first PCB board 201, a second PCB board 202, and a third PCB board 203. These three PCB boards are nested within the magnetic legs 10 of the magnetic core structure via through-holes. For example, the first primary winding 40 is disposed on the first PCB board 201, the second primary winding 50 is disposed on the third PCB board 203, and the buck inductor winding 30 is disposed on the second PCB board 202. When these three PCB boards are nested within the magnetic legs 10, the second PCB board 202 is positioned between the first and second PCB boards 201 and 202. In other words, the PCB boards 201, 202, and third PCB board 203 can be arranged in this order, either top-down or bottom-up. Optionally, in this embodiment, the magnetic flux generated by the first primary winding 40 and the magnetic flux generated by the second primary winding 50 have the same loop direction, and both are orthogonal to the magnetic flux loop generated by the winding 30 of the Buck inductor.

[0043] On the one hand, the present invention integrates the primary winding of the LLC transformer and the winding 30 of the Buck inductor into the same magnetic core structure. Simultaneously, the LLC transformer's leakage inductance replaces the LLC transformer's resonant inductor. This utilizes a single magnetic core structure to integrate the three magnetic components of the Sigma converter—the LLC transformer, the resonant inductor, and the Buck inductor—further reducing the volume occupied by the magnetic components, thereby increasing the power density of the Sigma converter. On the other hand, because the second PCB board 202 is located between the first PCB board 201 and the third PCB board 203, the magnetic flux loop generated by the Buck inductor winding 30 is orthogonal to the magnetic flux loops generated by the first and second primary windings. Consequently, the coupling coefficient between the first primary winding 40 and the Buck inductor winding 30 is zero, and the coupling coefficient between the second primary winding 50 and the Buck inductor winding 30 is also zero.

[0044] It should be noted that the magnetic core structure actually further includes a fourth PCB board and a fifth PCB board, which are used to respectively arrange a first secondary winding corresponding to the first primary winding and a second secondary winding corresponding to the second primary winding. When the first PCB board 201, the second PCB board 202, and the third PCB board 203 are arranged in a top-down order, the fourth PCB board is located above the first PCB board 201 and the fifth PCB board is located below the third PCB board. When the first PCB board 201, the second PCB board 202, and the third PCB board 203 are arranged in a bottom-up order, the fifth PCB board is located above the third PCB board 203 and the fourth PCB board is located below the first PCB board 201.

[0045] Since the forms of the two secondary windings on the fourth PCB board and the fifth PCB board do not affect the technical effects of the present invention, these two parts are not considered and are not illustrated in the drawings.

[0046] Optionally, the magnetic core structure includes a first magnetic leg 101, a second magnetic leg 102, a third magnetic leg 103 and a fourth magnetic leg 104, and the first PCB board 201, the second PCB board 202 and the third PCB board 203 each include four through holes and are nested on the first magnetic leg 101, the second magnetic leg 102, the third magnetic leg 103 and the fourth magnetic leg 104 through the four through holes.

[0047] For example, Figure 3-4 As shown, in the above magnetic core structure, the first primary winding 40 includes a first sub-winding WD1 surrounding the first magnetic leg 101, whose head end is connected to the resonant capacitor of the LLC transformer, and the second primary winding 50 includes a second sub-winding WD2 surrounding the first magnetic leg 101; wherein,

[0048] The first sub-winding WD1 surrounds the first magnetic leg 101 counterclockwise from outside to inside, and its end is connected to the beginning of the second sub-winding WD2 through the first via hole. The second sub-winding WD2 surrounds the first magnetic leg 101 counterclockwise from inside to outside.

[0049] Specifically, the starting end of the first sub-winding WD1 in the first primary winding 40 can be connected to the resonant capacitor of the LLC transformer through a via, and surround the first magnetic leg 101 counterclockwise from the outside to the inside, and the end is connected to the starting end of the second sub-winding WD2 through the first via. The second sub-winding WD2 then surrounds the first magnetic leg 101 counterclockwise from the inside to the outside. Using Lenz's law, it can be determined that the directions of the magnetic flux generated by the first sub-winding WD1 and the second sub-winding WD2 are both upward along the first magnetic leg 101.

[0050] Optionally, the second primary winding 50 includes a third sub-winding WD3 surrounding the second magnetic leg 102, the head end of which is connected to the end of the second sub-winding WD2, and the first primary winding 40 includes a fourth sub-winding WD4 surrounding the second magnetic leg 102; wherein,

[0051] The third sub-winding WD3 surrounds the second magnetic leg 102 counterclockwise from outside to inside, and its end is connected to the beginning of the fourth sub-winding WD4 through the second via hole. The fourth sub-winding WD4 surrounds the second magnetic leg 102 counterclockwise from inside to outside.

[0052] Please continue to see Figure 3-4The beginning of the third sub-winding WD3 in the second primary winding 50 is connected to the end of the second sub-winding WD2. The third sub-winding WD3 surrounds the second magnetic leg 102 counterclockwise from the outside to the inside, and the end is connected to the beginning of the fourth sub-winding WD4 in the first primary winding 40 through the second via hole. The fourth sub-winding WD4 surrounds the second magnetic leg 102 counterclockwise from the inside to the outside. Based on Lenz's law, it can be seen that the direction of the magnetic flux generated by the third and fourth sub-windings is upward along the second magnetic leg 102.

[0053] Furthermore, the first primary winding 40 includes a fifth sub-winding WD5 surrounding the third magnetic leg 103, the head end of which is connected to the end of the fourth sub-winding WD4, and the second primary winding 50 includes a sixth sub-winding WD6 surrounding the third magnetic leg 103; wherein,

[0054] The fifth sub-winding WD5 surrounds the third magnetic leg 103 clockwise from outside to inside, and its end is connected to the beginning of the sixth sub-winding WD6 through the third via hole. The sixth sub-winding WD6 surrounds the third magnetic leg 103 clockwise from inside to outside.

[0055] The second primary winding 50 includes a seventh sub-winding WD7 surrounding the fourth magnetic leg 104, the head end of which is connected to the end of the sixth sub-winding WD6, and the first primary winding 40 includes an eighth sub-winding WD8 surrounding the fourth magnetic leg 104; wherein,

[0056] The seventh sub-winding WD7 surrounds the fourth magnetic leg 104 counterclockwise from the inside to the outside, and its end is connected to the head end of the eighth sub-winding WD8 through the fourth via hole. The eighth sub-winding WD8 surrounds the fourth magnetic leg 104 clockwise from the inside to the outside, and its end is grounded.

[0057] Similarly, Lenz's law is used to determine the directions of the magnetic fluxes generated by the fifth sub-winding WD5, the sixth sub-winding WD6, the seventh sub-winding WD7, and the eighth sub-winding WD8. Obviously, the directions of the magnetic fluxes generated by the fifth sub-winding WD5 and the sixth sub-winding WD6 are both downward along the third magnetic leg 103, and the directions of the magnetic fluxes generated by the seventh sub-winding WD7 and the eighth sub-winding WD8 are both downward along the fourth magnetic leg 104.

[0058] Figure 5-6 is a schematic diagram of a magnetic flux loop generated by the first primary winding 40 and the second primary winding 50 provided in an embodiment of the present invention, wherein: Figure 6 for Figure 5It can be seen that after the first primary winding 40 and the second primary winding 50 are designed in the above manner, the magnetic flux generated by the first primary winding 40 forms two magnetic flux loops, wherein the magnetic flux generated by the fourth sub-winding WD4 and the fifth sub-winding WD5 forms a first magnetic flux loop through the second magnetic leg 102, the first PCB board 201, the third magnetic leg 103 and the third PCB board 203, and the magnetic flux generated by the first sub-winding WD1 and the eighth sub-winding WD8 forms a second magnetic flux loop through the first magnetic leg 101, the first PCB board 201, the fourth magnetic leg 104 and the third PCB board 204. 03 forms a second magnetic flux loop; similarly, the magnetic flux generated by the second primary winding 50 also forms two magnetic flux loops, namely: the magnetic flux generated by the third sub-winding WD3 and the sixth sub-winding WD6 forms a first magnetic flux loop through the second magnetic leg 102, the first PCB board 201, the third magnetic leg 103 and the third PCB board 203, and the magnetic flux generated by the second sub-winding WD2 and the seventh sub-winding WD7 forms a second magnetic flux loop through the first magnetic leg 101, the first PCB board 201, the fourth magnetic leg 104 and the third PCB board 203.

[0059] It should be noted that Figure 5 and Figure 6 The arrows shown in FIG are used to indicate the direction of the magnetic flux loop formed.

[0060] Figure 7 FIG. 1 is a schematic diagram of an inductor winding in a Buck topology according to an embodiment of the present invention. Figure 7 As shown, in a direction perpendicular to the plane where the second PCB board 202 is located, the orthographic projection of the winding 30 of the Buck inductor is S-shaped.

[0061] Figure 8-9 is a schematic diagram of a magnetic flux loop generated by a Buck inductor provided in an embodiment of the present invention, wherein: Figure 9 for Figure 8 Specifically, please refer to the cross-sectional view at BB'. Figure 7-9 , Figure 7 The arrow in the middle indicates the direction of current flow. Therefore, using Lenz's law, we can determine that the magnetic flux generated by the Buck inductor winding 30 at the first and fourth magnetic legs 101 and 104 is directed downward along the first and fourth magnetic legs, respectively, while the magnetic flux generated at the second and third magnetic legs 102 and 103 is directed upward along the second and third magnetic legs, respectively. Therefore, the magnetic flux generated by the Buck inductor winding 30 also forms two magnetic flux loops. Specifically, the magnetic flux generated by the Buck inductor winding 30 forms a first magnetic flux loop through the third magnetic leg 103, the first PCB board 201, the fourth magnetic leg 104, and the third PCB board 203. Simultaneously, a second magnetic flux loop is formed through the second magnetic leg 102, the first PCB board 201, the first magnetic leg 101, and the third PCB board 203.

[0062] Obviously, the magnetic flux loops generated by the two primary windings of the LLC transformer are orthogonal to the magnetic flux loop generated by the winding 30 of the Buck inductor, that is, the coupling coefficient between the first primary winding 40 and the winding 30 of the Buck inductor and the coupling coefficient between the second primary winding 50 and the winding 30 of the Buck inductor are both 0.

[0063] It should be noted that in the magnetic core structure provided by the present invention, the first primary winding 40, the second primary winding 50, and the Buck inductor winding 30 only need to meet the following conditions: the magnetic flux loops generated by the first primary winding 40 and the second primary winding 50 are identical and orthogonal to the magnetic flux loop generated by the Buck inductor winding 30. Therefore, in other embodiments of the present invention, other designs of the first primary winding 40, the second primary winding 50, and the Buck inductor winding 30 may also be adopted.

[0064] Figure 10 is another schematic diagram of the first primary winding 40 provided in an embodiment of the present invention. Figure 11 is another schematic diagram of the second primary winding provided by an embodiment of the present invention. Figure 10-11 The first primary winding 40 includes a sub-winding WD1' surrounding the second magnetic leg 102, and the second primary winding 50 includes a sub-winding WD2' surrounding the second magnetic leg 102, wherein the sub-winding WD1' surrounds the second magnetic leg 102 counterclockwise from the outside to the inside, and its head end is connected to the resonant capacitor of the LLC transformer, and the end is connected to the head end of the sub-winding WD2' through the through hole 1, and the sub-winding WD2' surrounds the magnetic leg 102 counterclockwise from the inside to the outside.

[0065] The second primary winding 50 further includes a sub-winding WD3' surrounding the first magnetic leg 101, and the first primary winding 40 further includes a sub-winding WD4' surrounding the first magnetic leg 101. Optionally, the end of the sub-winding WD2' is connected to the beginning of the sub-winding WD3', and the sub-winding WD3' surrounds the first magnetic leg 101 clockwise from the inside to the outside. The end of the sub-winding WD3' is connected to the beginning of the sub-winding WD4' through the through hole 2, and the sub-winding WD4' surrounds the first magnetic leg 101 counterclockwise from the inside to the outside.

[0066] Furthermore, the first primary winding 40 also includes a sub-winding WD5' surrounding the fourth magnetic leg 104, and the second primary winding 50 also includes a sub-winding WD6' surrounding the fourth magnetic leg 104, wherein the end of the sub-winding 4 is connected to the beginning of the sub-winding WD5', the sub-winding WD5' surrounds the fourth magnetic leg 104 clockwise from the outside to the inside, and the end is connected to the sub-winding WD6' via the through hole 3, and the sub-winding WD6' surrounds the fourth magnetic leg 104 clockwise from the inside to the outside.

[0067] In addition, the second primary winding 50 and the first primary winding 40 further include a sub-winding WD7' and a sub-winding WD8' respectively surrounding the third magnetic leg 103. Figure 10-11 As shown, the end of the sub-winding WD6' is connected to the head end of the sub-winding, the sub-winding WD6' surrounds the third magnetic leg 103 clockwise from the outside to the inside, and the end is connected to the head end of the sub-winding WD8' through the through hole 4, the sub-winding WD8' surrounds the third magnetic leg 103 clockwise from the inside to the outside, and the end is grounded.

[0068] Figure 12 This is another schematic diagram of the winding of the Buck inductor provided by the embodiment of the present invention. Figure 10 、 11 When designing in the manner shown, the winding 30 of the Buck inductor also needs to be adjusted accordingly, such as Figure 12 As shown, in a direction perpendicular to the plane where the second PCB board 202 is located, the orthographic projection of the winding 30 of the Buck inductor is in the shape of a Chinese character "J".

[0069] Next, the orthogonal flux core structure for improving the power density of the Sigma converter provided by the present invention is simulated.

[0070] Specifically, this embodiment performs Maxwell simulation on the magnetic core structure, wherein the first primary inductance, the second primary inductance and the Buck inductance are Figure 1 The simulation results are shown in the shaded part. Figure 13 As shown, winding1 represents the winding of Buck inductor, wingding2 represents the primary winding of LLC transformer, Figure 11 The first, second, third, and fourth columns represent the operating frequency, the self-inductance of the Buck inductor, the self-inductance of the LLC transformer primary winding, and the mutual inductance of the LLC transformer primary winding and the Buck inductor winding, respectively. It can be seen that the mutual inductance of winding1 and wingding2 is three orders of magnitude smaller than their respective self-inductances and can be ignored in practical applications. Therefore, there is basically no coupling between the two.

[0071] It can be seen from the above embodiments that the beneficial effects of the present invention are:

[0072] The present invention provides an orthogonal magnetic flux core structure for improving the power density of a Sigma converter. The structure comprises a first PCB board, a second PCB board, and a third PCB board, all of which are nested on magnetic legs via through holes. The second PCB board is located between the first and third PCB boards. A first primary winding and a second primary winding are respectively arranged on the first and third PCB boards. The winding of a Buck inductor is arranged on the second PCB board. Since the leakage inductance of an LLC transformer can replace the resonant inductor of the LLC transformer, the present invention integrates the three magnetic components of the LLC transformer, the resonant inductor, and the Buck inductor in the Sigma converter using a single magnetic core structure, thereby further reducing the volume occupied by the magnetic components and facilitating improved power density of the Sigma converter.

[0073] In addition, since the magnetic flux loops generated by the first primary winding and the second primary winding are orthogonal to the magnetic flux loop generated by the winding of the Buck inductor, the coupling coefficient between the first primary winding and the winding of the Buck inductor can be made 0, and the coupling coefficient between the second primary winding and the winding of the Buck inductor can also be made 0.

[0074] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0075] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0076] Descriptions with reference to the terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" mean that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification.

[0077] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art of the present invention, without departing from the concept of the present invention, several simple deductions or substitutions can be made, which should be considered to fall within the scope of protection of the present invention.

Claims

1. An orthogonal flux core structure for improving the power density of a Sigma converter, characterized in that: include: A plurality of magnetic legs, a plurality of PCB boards nested on the magnetic legs, a winding of a Buck inductor, a first primary winding and a second primary winding of an LLC transformer; The multiple PCB boards include a first PCB board, a second PCB board, and a third PCB board, and the second PCB board is located between the first PCB board and the third PCB board; the first primary winding and the second primary winding are respectively arranged on the first PCB board and the third PCB board, and the winding of the Buck inductor is arranged on the second PCB board; wherein the leakage inductance of the LLC transformer is used to replace the resonant inductor of the LLC transformer, and the magnetic flux loop generated by the first primary winding and the second primary winding is the same and is orthogonal to the magnetic flux loop generated by the winding of the Buck inductor.

2. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 1, characterized in that: The magnetic core structure includes a first magnetic leg, a second magnetic leg, a third magnetic leg and a fourth magnetic leg. The first PCB board, the second PCB board and the third PCB board each include four through holes and are nested on the first magnetic leg, the second magnetic leg, the third magnetic leg and the fourth magnetic leg through the four through holes.

3. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 2, characterized in that: The first primary winding includes a first sub-winding surrounding a first magnetic leg, a head end of which is connected to a resonant capacitor of the LLC transformer, and the second primary winding includes a second sub-winding surrounding the first magnetic leg; wherein, The first sub-winding surrounds the first magnetic leg counterclockwise from outside to inside, and its end is connected to the head end of the second sub-winding through a first via hole. The second sub-winding surrounds the first magnetic leg counterclockwise from inside to outside.

4. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 3, characterized in that: The second primary winding includes a third sub-winding surrounding the second magnetic leg, the head end of which is connected to the end of the second sub-winding, and the first primary winding includes a fourth sub-winding surrounding the second magnetic leg; wherein, The third sub-winding surrounds the second magnetic leg counterclockwise from outside to inside, and its end is connected to the head end of the fourth sub-winding through a second via hole. The fourth sub-winding surrounds the second magnetic leg counterclockwise from inside to outside.

5. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 4, characterized in that: The first primary winding includes a fifth sub-winding surrounding the third magnetic leg, the head end of which is connected to the end of the fourth sub-winding, and the second primary winding includes a sixth sub-winding surrounding the third magnetic leg; wherein, The fifth sub-winding surrounds the third magnetic leg clockwise from outside to inside, and its end is connected to the head end of the sixth sub-winding through a third via hole. The sixth sub-winding surrounds the third magnetic leg clockwise from inside to outside.

6. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 5, characterized in that: The second primary winding includes a seventh sub-winding surrounding the fourth magnetic leg, the head end of which is connected to the end of the sixth sub-winding, and the first primary winding includes an eighth sub-winding surrounding the fourth magnetic leg; wherein, The seventh sub-winding surrounds the fourth magnetic leg counterclockwise from the inside to the outside, and its end is connected to the head end of the eighth sub-winding through the fourth via hole. The eighth sub-winding surrounds the fourth magnetic leg clockwise from the inside to the outside, and its end is grounded.

7. The orthogonal flux core structure for improving the power density of a Sigma converter according to claim 1, characterized in that: In a direction perpendicular to the plane where the second PCB board is located, the orthographic projection of the winding of the Buck inductor is S-shaped.

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