Three-phase OBC integrated transformer and power converter of PCB structure

Abstract

The utility model discloses a three -phase OBC integrated transformer of PCB structure and power converter relates to magnetic integrated transformer technical field, include: first magnetic core, three spliced second magnetic core and be located between first magnetic core and second magnetic core's PCB board, first magnetic core is provided with a plurality of first middle column, is provided with a plurality of perforation on the PCB board, three second magnetic cores are provided with the second middle column with first middle column one -to -one correspondence, and first middle column passes through corresponding perforation and is matched with corresponding second middle column and touches, first winding, second winding and third winding are sequentially arranged on the PCB board, and first winding, second winding and third winding correspond respectively and coaxial arrangement with the perforation, and first winding and second winding between and second winding and third winding between series connection. The magnetic circuit of three single -phase transformers is physically integrated in the compact magnetic core assembly, reduces the overall volume, reduces production cost, simplifies assembly technology.

Description

Technical Field

[0001] This utility model relates to the field of magnetic integrated transformer technology, and in particular to a three-phase OBC integrated transformer and power converter with a PCB structure. Background Technology

[0002] Traditional magnetic component designs are no longer sufficient to meet the comprehensive requirements of modern electronic devices in terms of performance, size, and cost, especially given the increasingly fierce competition in the new energy vehicle market, where vehicle size and efficiency have reached new heights. Small size, high power, high frequency, integration, intelligence, and high cost-effectiveness have become requirements for automakers.

[0003] On-board charger (OBC) transformers are core components of devices used to convert AC power from the power grid into DC power and to charge electric vehicle batteries. Their working principle is based on power electronics technology, which enables power transmission through AC-DC conversion.

[0004] Existing OBC transformers mainly consist of multiple magnetic cores, multiple sets of winding coils, and a frame. Multiple magnetic cores and multiple sets of winding coils are stacked and installed on the frame according to the assembly sequence. This results in a large overall size of the transformer, high manufacturing cost, poor manufacturing consistency, and complicated processing steps, resulting in high power loss and low energy conversion density. Utility Model Content

[0005] To address the aforementioned issues, this invention proposes a three-phase OBC integrated transformer and power converter with a PCB structure. The core structure consists of three sets of second magnetic cores with double magnetic pillars and a first magnetic core shared at the top. This physically integrates the magnetic circuits of three single-phase transformers into a compact core assembly, reducing the overall volume, lowering production costs, and simplifying the assembly process.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In one aspect, the present invention provides a three-phase OBC integrated transformer with a PCB structure, comprising: a first magnetic core, three spliced ​​second magnetic cores, and a PCB board disposed between the first magnetic core and the second magnetic core; The first magnetic core is provided with several first central posts, and several through holes are provided on the PCB board. The three second magnetic cores are provided with second central posts that correspond one-to-one with the first central posts. The first central posts pass through the corresponding through holes and abut against the corresponding second central posts. The PCB board has a first winding, a second winding, and a third winding arranged sequentially. The first winding, the second winding, and the third winding are respectively aligned with the through holes and are coaxially arranged. The first winding and the second winding are connected in series, as are the second winding and the third winding.

[0007] As an alternative implementation, the PCB board has several copper layers. The first winding, the second winding, and the third winding each include several primary windings and secondary windings, and the several primary windings and secondary windings are sequentially arranged on each copper layer.

[0008] As an alternative implementation, between two adjacent copper layers, the primary windings of the same winding are connected in series, and the secondary windings of the same winding are connected in series.

[0009] As an alternative implementation, each copper layer has a number of pins for series connection in the first, second and third windings, with the pins staggered among themselves.

[0010] As an alternative implementation, on the first copper layer, the primary winding of the first winding is connected in series with the primary winding of the second winding, and the secondary winding of the second winding is connected in series with the secondary winding of the third winding; on the last copper layer, the primary winding of the second winding is connected in series with the primary winding of the third winding, and the secondary winding of the first winding is connected in series with the secondary winding of the second winding.

[0011] As an alternative implementation, each primary winding and secondary winding uses copper strips laid on each copper layer.

[0012] As an alternative implementation, a gap for filling adhesive is provided between the PCB board and the first magnetic core.

[0013] As an alternative implementation, the end of the second central column of the second magnetic core abuts against the first magnetic core to form a magnetic flux loop, with the middle phase magnetic flux and the two side phase magnetic fluxes having opposite directions.

[0014] As an alternative implementation, the top and bottom of the PCB board are provided with diaphragms for isolating the first and second magnetic cores.

[0015] Secondly, this utility model provides a power converter that adopts a three-phase OBC integrated transformer with a PCB structure proposed in the first aspect.

[0016] Compared with the prior art, the beneficial effects of this utility model are as follows: This invention proposes a three-phase OBC integrated transformer with a PCB structure, and designs a power converter based on it. The whole consists of a first magnetic core, three spliced ​​second magnetic cores, and a PCB board located between the first and second magnetic cores. Three sets of windings are arranged sequentially on the PCB board, and the three sets of windings and the three sets of second magnetic cores form a three-phase series integration. The magnetic core structure of the transformer is composed of three sets of second magnetic cores with double magnetic pillars and a first magnetic core shared at the top. The magnetic circuits of three single-phase transformers are physically integrated into a compact magnetic core assembly, reducing redundant space and materials between the three independent magnetic cores, greatly reducing the overall size and weight, and meeting the high power requirements of vehicle OBC.

[0017] The three-phase OBC integrated transformer with PCB structure proposed in this utility model has a unique magnetic core design. The end of the second column of the second magnetic core abuts against the first magnetic core to form a magnetic flux circuit. The middle winding and the two side windings are in opposite phase. The magnetic flux of the middle phase flowing through the common yoke is opposite in direction to the magnetic flux of the two side phases. Some of the magnetic flux is canceled out. This not only reduces the magnetic flux density of the common yoke and reduces magnetic core loss, but also enables a smaller cross-sectional area yoke, further promoting miniaturization and cost reduction, and ensuring the symmetry and independence of the three-phase magnetic circuit.

[0018] The advantages of this invention in additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 A schematic diagram of the overall structure of the three-phase OBC integrated transformer with PCB structure provided in Embodiment 1 of this utility model; Figure 2 An exploded view of a three-phase OBC integrated transformer with a PCB structure provided in Embodiment 1 of this utility model; Figure 3 This is a schematic diagram of the connection of windings on the same copper layer provided in Embodiment 1 of this utility model; Figure 4 This is a pin diagram of the first copper layer provided in Embodiment 1 of the present invention; Figure 5 This is a pin diagram of the second copper layer provided in Embodiment 1 of this utility model; Figure 6This is a pin diagram of the third copper layer provided in Embodiment 1 of this utility model; Figure 7 This is a pin diagram of the fourth copper layer provided in Embodiment 1 of this utility model; Figure 8 This is a pin diagram of the fifth copper layer provided in Embodiment 1 of this utility model; Figure 9 This is a pin diagram of the sixth copper layer provided in Embodiment 1 of this utility model; Figure 10 This is a pin diagram of the seventh copper layer provided in Embodiment 1 of this utility model; Figure 11 This is a pin diagram of the eighth copper layer provided in Embodiment 1 of this utility model; Among them, 1. First magnetic core; 2. Second magnetic core; 3. PCB board; 4. Through hole; 5. First center post; 6. Second center post; 7. Gap; 8. First winding; 9. Second winding; 10. Third winding; 11. Primary winding; 12. Secondary winding; 13. First copper layer; 14. Second copper layer; 15. Third copper layer; 16. Fourth copper layer; 17. Fifth copper layer; 18. Sixth copper layer; 19. Seventh copper layer; 20. Eighth copper layer; 21. First pin; 22. Second pin; 23. Third pin; 24. Fourth pin. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0022] It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0023] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this utility model. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that the terms "comprising" and "including," and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such process, method, product, or apparatus.

[0024] Where there is no conflict, the embodiments and features in the embodiments of this utility model can be combined with each other.

[0025] Example 1 This embodiment provides a three-phase OBC integrated transformer with a PCB structure. It adopts a multi-winding flat plate structure instead of the original multi-coil structure of the OBC three-phase transformer, and improves the mounting method of the frame, multiple magnetic cores and windings, reducing the overall size and manufacturing cost of the transformer, simplifying the processing steps, reducing copper loss and improving heat dissipation.

[0026] like Figures 1-2 As shown, it includes: a first magnetic core 1, three second magnetic cores 2 assembled together, and a PCB board 3 disposed between the first magnetic core 1 and the second magnetic core 2; The first magnetic core 1 is provided with a number of first central pillars 5, the PCB board 3 is provided with a number of through holes 4, and the three second magnetic cores 2 are provided with second central pillars 6 that correspond one-to-one with the first central pillars 5. The first central pillars 5 pass through the corresponding through holes 4 and abut against the corresponding second central pillars 6. The PCB board 3 is provided with a first winding 8, a second winding 9 and a third winding 10 in sequence, and the first winding 8, the second winding 9 and the third winding 10 are respectively corresponding to the through hole 4 and are coaxially arranged. The first winding 8 and the second winding 9 are connected in series and the second winding 9 and the third winding 10 are connected in series.

[0027] As an alternative implementation, the center-to-center distance between adjacent first central pillars 5 and the center-to-center distance between adjacent second central pillars 6 are matched with the center-to-center distance of the corresponding through holes 4 on the PCB board 3. The cross-sectional dimensions of the first central pillars 5 and the second central pillars 6 are matched with the dimensions of the corresponding through holes 4 to ensure accurate alignment during assembly and to avoid friction damage between the first magnetic core 1, the second magnetic core 2 and the PCB board 3. The sum of the lengths of the first central pillars 5 and the second central pillars 6 is matched with the thickness of the PCB board 3 to ensure that the magnetic circuit is connected after the first central pillars 5 and the second central pillars 6 come into contact.

[0028] In this embodiment, the PCB board 3 is formed by laminating several PP boards. Each PP board has a copper layer on one surface. On each copper layer, the first winding 8, the second winding 9, and the third winding 10 (corresponding to phases A, B, and C of the three-phase circuit, respectively) are arranged along the length of the PP board, as shown below. Figure 3 As shown.

[0029] The first winding 8, the second winding 9, and the third winding 10 each include several layers of primary winding 11 and secondary winding 12 (the primary winding 11 is connected to a three-phase AC input, and the secondary winding 12 outputs DC voltage). The several layers of primary winding 11 and secondary winding 12 are arranged sequentially on each copper layer, and each layer of primary winding 11 and secondary winding 12 is coaxially arranged with its corresponding through hole 4.

[0030] Between two adjacent copper layers, the primary winding 11 of the same winding is connected in series, and the secondary winding 12 of the same winding is connected in series.

[0031] As an alternative implementation, each copper layer has a number of pins for series connection, which are used to connect the primary windings 11 of the same winding between two adjacent copper layers in series, and to connect the secondary windings 12 of the same winding between two adjacent copper layers in series. The pins are staggered to avoid pin interference and facilitate wiring and soldering.

[0032] Specifically: On the first and last copper layers, both the primary winding 11 and the secondary winding 12 are provided with one pin. On the intermediate copper layers, both the primary winding 11 and the secondary winding 12 are provided with two pins. Between two adjacent copper layers, for the same winding, the pin of the primary winding 11 of the upper layer is connected to any pin of the primary winding 11 of the lower layer, and the pin of the secondary winding 12 of the upper layer is connected to any pin of the secondary winding 12 of the lower layer.

[0033] As an alternative implementation, 4-8 copper layers are preferably designed on the PCB board 3, with a total thickness of 3.86mm ± 0.5mm.

[0034] This embodiment uses an 8-layer copper layer as an example, such as Figures 4-11 As shown, specifically: On the first copper layer 13, each winding group has a first pin 21 on both the primary winding 11 and the secondary winding 12. On the second to seventh copper layers 19, each winding group has two second pins 22 on the primary winding 11 and two third pins 23 on the secondary winding 12. On the eighth copper layer 20, each winding group has a fourth pin 24 on both the primary winding 11 and the secondary winding 12.

[0035] Between the first copper layer 13 and the second copper layer 14, for the same winding, the first pin 21 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the second copper layer 14; the first pin 21 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the second copper layer 14. Between the second copper layer 14 and the third copper layer 15, for the same winding, another second pin 22 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the third copper layer 15; another third pin 23 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the third copper layer 15. Between the third copper layer 15 and the fourth copper layer 16, for the same winding, another second pin 22 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the fourth copper layer 16; another third pin 23 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the fourth copper layer 16. Between the fourth copper layer 16 and the fifth copper layer 17, for the same winding, another second pin 22 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the fifth copper layer 17; another third pin 23 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the fifth copper layer 17. Between the fifth copper layer 17 and the sixth copper layer 18, for the same winding, another second pin 22 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the sixth copper layer 18; another third pin 23 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the sixth copper layer 18. Between the sixth copper layer 18 and the seventh copper layer 19, for the same winding, another second pin 22 of the primary winding 11 is connected to any second pin 22 of the primary winding 11 on the seventh copper layer 19; another third pin 23 of the secondary winding 12 is connected to any third pin 23 of the secondary winding 12 on the seventh copper layer 19. Between the seventh copper layer 19 and the eighth copper layer 20, for the same winding, another second pin 22 of the primary winding 11 is connected to the fourth pin 24 of the primary winding 11 on the eighth copper layer 20; another third pin 23 of the secondary winding 12 is connected to the fourth pin 24 of the secondary winding 12 on the eighth copper layer 20.

[0036] This results in a series integration of a single primary winding and a series integration of secondary windings.

[0037] In this embodiment, as Figure 3 As shown, the series connection between the three windings is as follows: on the first copper layer, the primary winding 11 of the first winding 8 is connected in series with the primary winding 11 of the second winding 9, and the secondary winding 12 of the second winding 9 is connected in series with the secondary winding 12 of the third winding 10; on the last copper layer, the primary winding 11 of the second winding 9 is connected in series with the primary winding 11 of the third winding 10, and the secondary winding 12 of the first winding 8 is connected in series with the secondary winding 12 of the second winding 9, thereby forming a series integrated configuration between the three windings.

[0038] As an alternative implementation, on each copper layer, the primary winding 11 and the secondary winding 12 are formed by copper sheet etching. Each primary winding 11 and secondary winding 12 is arranged in a ring around the corresponding through hole 4 (coaxial with the through hole 4), and the spacing between adjacent windings meets the insulation requirements.

[0039] In this embodiment, on each copper layer, the second winding 9 is located between the first winding 8 and the third winding 10. The ends of the first winding 8 and the third winding 10 that are far apart are provided with solder pads to facilitate soldering and assembly and simplify the processing steps.

[0040] In this embodiment, after the first central column passes through the corresponding through hole 4 on the PCB board 3, its end face abuts against the end face of the second central column 6. A gap 7 for filling glue is provided between the PCB board 3 and the first magnetic core 1 to reduce the magnetic core cracking caused by glue expansion and ensure that there is no obvious air gap in the magnetic circuit.

[0041] In this embodiment, the PCB board 3 uses a material with high thermal conductivity (above 1W / mk), which has excellent heat dissipation and allows for a smaller copper area.

[0042] In this embodiment, insulating films are provided on the top (side facing the first magnetic core 1) and bottom (side facing the second magnetic core 2) of the PCB board 3 to isolate the magnetic cores and meet the pressure resistance requirements. The magnetic cores are fixed together by dispensing adhesive.

[0043] The three-phase OBC integrated transformer with PCB structure proposed in this embodiment consists of a first magnetic core, three spliced ​​second magnetic cores, and a PCB board located between the first and second magnetic cores. Three sets of windings are sequentially arranged on the PCB board, and the three sets of windings and the three sets of second magnetic cores form a three-phase series integration. The core structure of the transformer is composed of three sets of second magnetic cores with double magnetic pillars and a first magnetic core shared at the top. The magnetic circuits of three single-phase transformers are physically integrated into a compact core assembly, reducing redundant space and materials between the three independent magnetic cores, greatly reducing the overall size and weight, and meeting the high power requirements of vehicle OBC.

[0044] Meanwhile, through a unique magnetic core design, the end of the second column of the second magnetic core abuts against the first magnetic core, forming a magnetic flux loop. The middle winding and the two side windings are in opposite phases. The middle phase magnetic flux flowing through the common yoke is opposite in direction to the two side phase magnetic flux, and some magnetic flux is canceled out. This not only reduces the magnetic flux density of the common yoke and reduces magnetic core loss, but also enables a smaller cross-sectional area yoke, further promoting miniaturization and cost reduction, and ensuring the symmetry and independence of the three-phase magnetic circuit.

[0045] In addition, the above PCB design improves production consistency, reliability and heat dissipation performance, makes it easier to process and automate, reduces production costs, simplifies assembly processes, reduces winding leakage inductance and improves EMI performance.

[0046] Example 2 This embodiment provides a power converter that uses the three-phase OBC integrated transformer with the PCB structure described in Embodiment 1. Its detailed principle is the same as that of the three-phase OBC integrated transformer with the PCB structure provided in Embodiment 1, and will not be repeated here.

[0047] Although the specific embodiments of the present utility model have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present utility model. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solution of the present utility model are still within the scope of protection of the present utility model.

Claims

1. A three-phase OBC integrated transformer with a PCB structure, characterized in that, include: A first magnetic core, three spliced ​​second magnetic cores, and a PCB board disposed between the first magnetic core and the second magnetic core; The first magnetic core is provided with a plurality of first central posts, and the PCB board is provided with a plurality of through holes. The three second magnetic cores are provided with second central posts that correspond one-to-one with the first central posts. The first central posts pass through the corresponding through holes and abut against the corresponding second central posts. The PCB board is provided with a first winding, a second winding and a third winding in sequence, and the first winding, the second winding and the third winding are respectively corresponding to the through hole and are coaxially arranged. The first winding and the second winding are connected in series and the second winding and the third winding are connected in series.

2. A three-phase OBC integrated transformer with a PCB structure as described in claim 1, characterized in that, The PCB board has several copper layers. The first winding, the second winding, and the third winding each include several primary windings and secondary windings, and the several primary windings and secondary windings are arranged sequentially on each copper layer.

3. A three-phase OBC integrated transformer with a PCB structure as described in claim 2, characterized in that, Between two adjacent copper layers, the primary windings of the same winding are connected in series, and the secondary windings of the same winding are connected in series.

4. A three-phase OBC integrated transformer with a PCB structure as described in claim 3, characterized in that, On each copper layer, the first winding, the second winding, and the third winding are provided with a number of pins for series connection, and the pins are staggered among themselves.

5. A three-phase OBC integrated transformer with a PCB structure as described in claim 2, characterized in that, On the first copper layer, the primary winding of the first winding is connected in series with the primary winding of the second winding, and the secondary winding of the second winding is connected in series with the secondary winding of the third winding; on the last copper layer, the primary winding of the second winding is connected in series with the primary winding of the third winding, and the secondary winding of the first winding is connected in series with the secondary winding of the second winding.

6. A three-phase OBC integrated transformer with a PCB structure as described in claim 2, characterized in that, Each primary winding and secondary winding is constructed using copper strips laid on each copper layer.

7. A three-phase OBC integrated transformer with a PCB structure as described in claim 1, characterized in that, A gap for filling adhesive is provided between the PCB board and the first magnetic core.

8. A three-phase OBC integrated transformer with a PCB structure as described in claim 1, characterized in that, The end of the second central column of the second magnetic core abuts against the first magnetic core, forming a magnetic flux loop, with the middle phase magnetic flux and the two side phase magnetic fluxes in opposite directions.

9. A three-phase OBC integrated transformer with a PCB structure as described in claim 1, characterized in that, The PCB board is provided with diaphragms at the top and bottom for isolating the first magnetic core and the second magnetic core.

10. A power converter employing a three-phase OBC integrated transformer with a PCB structure as described in any one of claims 1-9.

Images