CN220491712U - Planar transformer - Google Patents
Planar transformer Download PDFInfo
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- CN220491712U CN220491712U CN202322089007.2U CN202322089007U CN220491712U CN 220491712 U CN220491712 U CN 220491712U CN 202322089007 U CN202322089007 U CN 202322089007U CN 220491712 U CN220491712 U CN 220491712U
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- 238000004804 winding Methods 0.000 claims abstract description 87
- 239000002184 metal Substances 0.000 claims description 10
- 238000002955 isolation Methods 0.000 abstract description 18
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 4
- 230000003071 parasitic effect Effects 0.000 description 4
- 230000008901 benefit Effects 0.000 description 3
- 239000003990 capacitor Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 239000011810 insulating material Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- LAHWLEDBADHJGA-UHFFFAOYSA-N 1,2,4-trichloro-5-(2,5-dichlorophenyl)benzene Chemical compound ClC1=CC=C(Cl)C(C=2C(=CC(Cl)=C(Cl)C=2)Cl)=C1 LAHWLEDBADHJGA-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
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Abstract
The utility model discloses a planar transformer, comprising: the PCB comprises at least two plate layers, windings arranged on the plate layers, a first through hole and a second through hole, wherein the windings comprise primary plane windings and secondary plane windings, the primary plane windings are arranged around the first through hole, and the secondary plane windings are arranged around the second through hole; a magnetic core unit including an upper magnetic sheet and a lower magnetic sheet, the upper magnetic sheet and the lower magnetic sheet being sandwiched to form a closed magnetic circuit; the closed magnetic circuit penetrates through the first through hole and the second through hole; primary plane windings distributed on different plate layers are connected to form primary plane winding units, and secondary plane windings distributed on different plate layers are connected to form secondary plane winding units, wherein the windings are wirings of a PCB (printed circuit board); the utility model ensures low cost, small volume and high isolation withstand voltage of the transformer body, and simultaneously greatly reduces the isolation capacitance of the transformer body, thereby meeting the special requirements of low isolation capacitance of systems such as IGBT/SiC driving power supply and the like.
Description
Technical Field
The utility model relates to the technical field of transformers, in particular to a planar transformer.
Background
The IGBT and the SiC MOSFET are high-power switching devices, are widely used for motor driving, power conversion, inverters and the like, and are the heart of the modern industry. Unlike other conventional DC/DC power supplies, the driving power supply is more special to apply, and mainly has the following 4-point core requirements: suitable output voltages, high isolation, high CMTI, low isolation capacitance. Wherein low isolation capacitance is particularly important for the impact of IGBT/SiC operational reliability.
As shown in fig. 1, fig. 1 is a simplified diagram of a circuit in practical application of an IGBT/SiC drive power supply, in which a DC/DC isolation conversion module is the IGBT/SiC drive power supply, and C is an isolation capacitor parasitic inside the IGBT/SiC drive power supply.
However, high frequency high voltage switches generate high frequency leakage currents that flow through the isolation capacitors:
the current generates negative voltage through parasitic inductance, and therefore the IGBT/SiC is damaged:
it can be seen that the larger C, the larger the high frequency leakage current, the larger the negative voltage it generates via parasitic inductance, and the larger the negative voltage, the greater the threat to IGBT/SiC.
In recent years, various industries are moving toward the trend of chip mounting and miniaturization, and a planar chip mounting transformer is also produced, and a traditional planar transformer adopts a sandwich structure, wherein isolated coils at two sides are opposite up and down, as shown in fig. 2, the planar transformer is a traditional planar transformer, and isolated primary windings and isolated secondary windings are positioned on different plate layers and opposite up and down.
The calculation formula of the capacitance is as follows:
wherein, the opposite areas between the S poles are opposite; epsilon is the dielectric constant of the insulating material and depends on the insulating material itself; pi is the circumference ratio; k is the electrostatic force constant, k=8.9880x10nm 2 /C 2 The method comprises the steps of carrying out a first treatment on the surface of the d is the vertical distance between the two poles.
It can be seen that, in the planar transformer stacked up and down, the vertical distance d is short due to the large facing area S between the two poles, and the calculated isolation capacitance C is relatively large, and as shown in the previous analysis, the larger the isolation capacitance C is, the larger the high-frequency leakage current is, the larger the negative voltage generated by parasitic inductance is, and the larger the negative voltage is, the larger the threat to IGBT/SiC is.
Disclosure of Invention
The utility model aims to overcome at least one defect in the prior art and provide a planar transformer with small volume, high isolation withstand voltage and low isolation capacitance.
In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:
there is provided a planar transformer comprising:
the PCB comprises at least two plate layers, windings arranged on the plate layers, a first through hole and a second through hole, wherein the first through hole and the second through hole are arranged side by side, the windings comprise primary plane windings and secondary plane windings, the primary plane windings are arranged on the periphery of the first through hole, and the secondary plane windings are arranged on the periphery of the second through hole;
a magnetic core unit including an upper magnetic sheet and a lower magnetic sheet, the upper magnetic sheet and the lower magnetic sheet being sandwiched to form a closed magnetic circuit;
the closed magnetic circuit penetrates the first through hole and the second through hole;
the primary plane windings distributed on different plate layers are connected to form a primary plane winding unit, and the secondary plane windings distributed on different plate layers are connected to form a secondary plane winding unit, wherein the windings are wiring of the PCB.
Preferably, the PCB board is provided with metal through holes, and windings on different board layers are connected through the metal through holes.
Preferably, the upper magnetic sheet is a U-shaped magnetic core, the lower magnetic sheet is an I-shaped magnetic core, and the upper magnetic sheet is in contact with the lower magnetic sheet through the first through hole and the second through hole.
Preferably, the upper magnetic sheet is a C-shaped magnetic core, the lower magnetic sheet is an I-shaped magnetic core, and the upper magnetic sheet contacts with the lower magnetic sheet through the first through hole and the second through hole.
Preferably, the upper magnetic sheet is a U-shaped magnetic core, the lower magnetic sheet is a U-shaped magnetic core, and the upper magnetic sheet is in contact with the lower magnetic sheet through the first through hole and the second through hole.
Preferably, the secondary planar winding unit includes a secondary first planar winding unit and a secondary second planar winding unit.
Preferably, a part of the outer surface of the magnetic core unit is spaced from a part of the outer surface of the PCB by a preset distance.
Compared with the prior art, the utility model has the beneficial effects that: through the magnetic core unit that adopts upper magnetic sheet and lower magnetic sheet clamp to form, the primary side plane winding unit of isolation and vice side plane winding unit are around arranging on two posts of magnetic core unit respectively, and the winding is the wiring of PCB board, in this way, increased window benefit rate, reduced the magnetic core size, more importantly, compared with former vice side upper and lower stromatolite, reduced the just area between two poles of the earth greatly, and more easily pull open the perpendicular distance between two poles of the earth to isolation capacitance has been reduced to a great extent.
Drawings
FIG. 1 is a simplified diagram of the internal circuit of an IGBT/SiC drive power supply in practical application;
FIG. 2 is a schematic diagram of a conventional planar transformer;
FIG. 3 is an exploded view of the planar transformer according to the present utility model;
FIG. 4 is a cross-sectional view of a planar transformer according to the present utility model;
fig. 5 is a schematic diagram of a planar transformer of the present utility model comprising three planar winding units:
fig. 6 is a schematic circuit diagram of a planar transformer according to the present utility model including three planar winding units.
Detailed Description
In order to make the objects, technical solutions and advantages of the present utility model more apparent, the present utility model will be further described in detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.
As shown in fig. 3 and 4, fig. 3 is an exploded schematic view of the planar transformer according to the present embodiment, and fig. 4 is a cross-sectional view of the planar transformer according to the present embodiment, in which a planar transformer 10 is provided, including:
the PCB 101 comprises at least two plate layers, windings arranged on the plate layers, a first through hole 101-1 and a second through hole 101-2 which are arranged side by side, wherein the windings comprise primary plane windings and secondary plane windings, the primary plane windings are arranged on the periphery of the first through hole 101-1, and the secondary plane windings are arranged on the periphery of the second through hole 101-2;
a magnetic core unit 102 including an upper magnetic sheet 102-1 and a lower magnetic sheet 102-2, the upper magnetic sheet 102-1 and the lower magnetic sheet 102-2 being sandwiched to form a closed magnetic circuit;
the closed magnetic circuit penetrates the first through-hole 101-1 and the second through-hole 101-2;
the primary plane windings distributed on different plate layers are connected to form a primary plane winding unit 101-3, and the secondary plane windings distributed on different plate layers are connected to form a secondary plane winding unit, wherein the windings are wiring of the PCB.
Specifically, the first through-hole 101-1 and the second through-hole 101-2 may be, but not limited to, arranged in parallel; the magnetic core unit 102 is formed by clamping an upper magnetic sheet 102-1 and a lower magnetic sheet 102-2, wherein the clamping mode can be driven by external force, for example, a metal cover with a specific shape can be used for fixing the magnetic core unit, and can also be chemical adhesive; the outer surface of at least a portion of the magnetic core unit 102 is spaced a predetermined distance from the outer surface of at least a portion of the PCB panel 101. The windings are arranged on at least one plate layer, and in the specific implementation process, each plate layer is provided with the windings and two through holes, wherein the windings are arranged around the through holes.
Specifically, the PCB board is provided with metal through holes, and windings on different board layers are connected through the metal through holes. In the specific implementation process, as shown in fig. 5 and 6, the secondary plane winding unit comprises a secondary first plane winding unit 101-4 and a secondary second plane winding unit 101-5, windings distributed on different plate layers and arranged around the first through hole 101-1 are connected in series through metal vias (g groups) to form a primary plane winding unit 101-3, windings distributed on different plate layers and arranged around the second through hole 101-2 are connected in series through metal vias (h groups) to form a secondary first plane winding unit 101-4, and windings distributed on different plate layers and arranged around the second through hole 101-2 are connected in series through metal vias (i groups) to form a secondary first plane winding unit 101-5.
In one embodiment, the upper magnetic sheet 102-1 is a U-shaped magnetic core, the lower magnetic sheet 102-2 is an I-shaped magnetic core, and the upper magnetic sheet 102-1 contacts the lower magnetic sheet 102-2 through the first through hole and the second through hole.
In one embodiment, the upper magnetic sheet 102-1 is a C-shaped magnetic core, the lower magnetic sheet 102-2 is an I-shaped magnetic core, and the upper magnetic sheet 102-1 contacts the lower magnetic sheet 102-2 through the first through hole and the second through hole.
In one embodiment, the upper magnetic sheet 102-1 is a U-shaped magnetic core, the lower magnetic sheet 102-2 is a U-shaped magnetic core, and the upper magnetic sheet 102-1 contacts the lower magnetic sheet 102-2 through the first through hole and the second through hole.
In the specific implementation process, the magnetic core unit 102 is a UI-type magnetic core, the upper magnetic sheet 102-1 is a U-type magnetic core, the lower magnetic sheet 102-1 is an I-type magnetic core, the part of the magnetic core passing through the first through hole 101-1 is called a first magnetic column, the part of the magnetic core passing through the second through hole 101-2 is called a second magnetic column, the primary side first planar winding unit 101-3 surrounds the first magnetic column, and the secondary side first planar winding unit 101-4 and the secondary side second planar winding unit 101-5 surround the second magnetic column.
Specifically, the PCB board includes pins a, b, c, d, e, f of the transformer body, and the primary side planar winding unit 101-3, the secondary side first planar winding unit 101-4, and the secondary side second planar winding unit 101-5 are connected with the pins a, b, c, d, e, f of the transformer body through the PCB wiring. Pins of the transformer body are exposed on the outer surface of the planar transformer, and the pins of the transformer body can be in various forms, such as copper-plated pins on the side wall, metal through holes and the like.
In this case, only one primary side plane winding unit is needed for isolating the primary side, and the secondary side is two-way output. In practice, the number of winding units separating the primary side from the secondary side may be increased or decreased according to actual needs, depending on the actual circuit topology and the number of output paths.
In the embodiment, each layer of the PCB is respectively provided with windings for isolating the primary side and the secondary side, and the requirements of isolating withstand voltage and isolating capacitance of the primary side and the secondary side are met by controlling the creepage distance of the primary side and the secondary side. In practice, the placement of windings on each board layer of the PCB may be determined according to actual performance requirements, cost requirements, volume requirements, isolation requirements, etc.
In the embodiment, the number of the PCB layers is 10, and in practical cases, the number of the PCB layers can be designed according to the specific requirements of turn ratio, winding width, winding spacing, current density and the like.
The planar transformer of this embodiment adopts the magnetic core unit formed by clamping the upper magnetic sheet 102-1 and the lower magnetic sheet 102-2, and the primary planar winding unit 101-3 and the secondary planar winding unit are respectively wound on two columns of the magnetic core unit 102, and the windings are the wiring of the PCB board 101, so that the window benefit rate is increased, the magnetic core size is reduced, more importantly, compared with the original primary secondary upper and lower lamination, the facing area between two poles is greatly reduced, and the vertical distance between two poles is more easily and conveniently pulled, thereby reducing the isolation capacitance to a great extent, and meeting the special requirements of low isolation capacitance of the IGBT/SiC driving power supply and other systems.
The above embodiments are merely preferred embodiments of the present utility model, and it should be noted that the above preferred embodiments should not be construed as limiting the present utility model. In addition, several modifications and variations may be made without departing from the spirit and scope of the utility model, and these modifications and variations should also be regarded as being within the scope of the utility model, and no further description of the embodiments is provided herein.
Claims (7)
1. A planar transformer, comprising:
the PCB comprises at least two plate layers, windings arranged on the plate layers, a first through hole and a second through hole, wherein the first through hole and the second through hole are arranged side by side, the windings comprise primary plane windings and secondary plane windings, the primary plane windings are arranged on the periphery of the first through hole, and the secondary plane windings are arranged on the periphery of the second through hole;
a magnetic core unit including an upper magnetic sheet and a lower magnetic sheet, the upper magnetic sheet and the lower magnetic sheet being sandwiched to form a closed magnetic circuit;
the closed magnetic circuit penetrates the first through hole and the second through hole;
the primary plane windings distributed on different plate layers are connected to form a primary plane winding unit, and the secondary plane windings distributed on different plate layers are connected to form a secondary plane winding unit, wherein the windings are wiring of the PCB.
2. The planar transformer of claim 1, wherein the PCB board is provided with metal vias through which windings on different ones of the board layers are connected.
3. The planar transformer of claim 1, wherein the upper magnetic sheet is a U-shaped magnetic core, the lower magnetic sheet is an I-shaped magnetic core, and the upper magnetic sheet is in contact with the lower magnetic sheet through the first through-hole and the second through-hole.
4. The planar transformer of claim 1, wherein the upper magnetic sheet is a C-type magnetic core, the lower magnetic sheet is an I-type magnetic core, and the upper magnetic sheet is in contact with the lower magnetic sheet through the first through-hole and the second through-hole.
5. The planar transformer of claim 1, wherein the upper magnetic sheet is a U-shaped magnetic core, the lower magnetic sheet is a U-shaped magnetic core, and the upper magnetic sheet is in contact with the lower magnetic sheet through the first through-hole and the second through-hole.
6. The planar transformer of any one of claims 1-5, wherein the secondary planar winding unit comprises a secondary first planar winding unit and a secondary second planar winding unit.
7. The planar transformer of claim 1, wherein a portion of the outer surface of the magnetic core unit is spaced a predetermined distance from a portion of the outer surface of the PCB.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322089007.2U CN220491712U (en) | 2023-08-04 | 2023-08-04 | Planar transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322089007.2U CN220491712U (en) | 2023-08-04 | 2023-08-04 | Planar transformer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN220491712U true CN220491712U (en) | 2024-02-13 |
Family
ID=89828311
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202322089007.2U Active CN220491712U (en) | 2023-08-04 | 2023-08-04 | Planar transformer |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN220491712U (en) |
-
2023
- 2023-08-04 CN CN202322089007.2U patent/CN220491712U/en active Active
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