A three-phase magnetic integrated transformer

Abstract

This utility model discloses a three-phase magnetic integrated transformer, including a base on which a filter inductor and a three-phase transformer are fixedly mounted. The filter inductor is composed of a first magnetic core, a second magnetic core, a third magnetic core, a fourth magnetic core, and three inductor coils connected by sharing a common magnetic core. The magnetic circuit integration significantly reduces the core volume. Both the second and first center columns are slotted, greatly increasing the core's Ae value without significantly increasing its volume, thus improving its power handling capacity. The product features a linear layout, a compact structure, and neat pinouts, facilitating PCB layout for upstream customers and reducing space occupancy. The filter inductor's shared magnetic core design saves on core usage and reduces product size. Furthermore, the segmented air gap and enlarged coil bore reduce eddy current losses and improve heat dissipation.

Description

Technical Field

[0001] This utility model relates to the field of magnetic integrated transformer technology, and more specifically, to a three-phase magnetic integrated transformer. Background Technology

[0002] The development of high-frequency switching devices: With the popularization of third-generation semiconductors, the operating frequency of power electronic devices has been greatly increased. High-frequency operation can significantly reduce the size of passive components, such as transformers and inductors.

[0003] However, the losses and parasitic parameters of traditional discrete magnetic components are more prominent at high frequencies: traditional discrete transformers and inductors occupy a lot of space, making it difficult to meet high power density designs. The copper and iron losses of discrete magnetic components are superimposed, and the core utilization rate is low, the heat dissipation effect is poor, and multiple magnetic components lead to complex circuit layout, difficult control of parasitic parameters, and high production costs. Therefore, we propose a three-phase magnetic integrated transformer. Utility Model Content

[0004] One objective of this invention is to provide a new technical solution for a three-phase magnetic integrated transformer.

[0005] According to a first aspect of the present invention, a three-phase magnetic integrated transformer is provided, including a base on which a filter inductor and a three-phase transformer are fixedly mounted. The filter inductor is composed of a first magnetic core, a second magnetic core, a third magnetic core, a fourth magnetic core, and three inductor coils connected by sharing a common magnetic core. The three-phase transformer is composed of two fifth magnetic cores and three transformer coils disposed between the two fifth magnetic cores.

[0006] Optionally, the fifth magnetic core is provided with three second intermediate columns, and the transformer coil is configured to be wound in two parts, the primary side and the secondary side, on the second intermediate columns.

[0007] Optionally, the three second central pillars are of the same size and are evenly distributed on the fifth magnetic core.

[0008] Optionally, the first magnetic core, the second magnetic core, and the third magnetic core are all fixedly mounted with a first central post, and the first central post is mounted in a slot shape.

[0009] Optionally, an insulating gasket is fixedly installed on the first central column, and a magnetic sheet is fixedly installed on the insulating gasket.

[0010] Optionally, the base is square, and the center of the base is hollowed out.

[0011] According to one embodiment of this disclosure, a three-phase transformer employs three second-column integrated magnetic cores. This magnetic circuit integration significantly reduces the core volume. Both the second and first columns are slotted, greatly increasing the core's Ae value without a substantial increase in core volume, thus enhancing the core's power handling capability. The product features a linear layout, compact structure, and neat pinouts, facilitating upstream customer board placement and reducing space occupancy. The filter inductors are assembled using shared magnetic cores, saving core usage and reducing product volume. Furthermore, the segmented air gap and enlarged coil bores reduce eddy current losses and improve heat dissipation.

[0012] Other features and advantages of the present invention will become clear from the following detailed description of exemplary embodiments of the present invention with reference to the accompanying drawings. Attached Figure Description

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present invention and, together with their description, serve to explain the principles of the present invention.

[0014] Figure 1 This is a schematic diagram of the overall structure of a three-phase magnetic integrated transformer in one embodiment;

[0015] Figure 2 This is a front view of a three-phase magnetic integrated transformer in one embodiment.

[0016] Figure 3 This is an exploded structural diagram of a three-phase magnetic integrated transformer in one embodiment;

[0017] Figure 4 This is a schematic diagram of the fifth magnetic core structure of a three-phase magnetic integrated transformer in one embodiment;

[0018] Figure 5 This is a schematic diagram of the first magnetic core structure of a three-phase magnetic integrated transformer in one embodiment;

[0019] Figure 6 This is a schematic diagram of the filter inductor structure of a three-phase magnetic integrated transformer in one embodiment;

[0020] Figure 7 This is a schematic diagram of the side structure of the first magnetic core of a three-phase magnetic integrated transformer in one embodiment;

[0021] Figure 8 This is a schematic diagram of the transformer coil structure of a three-phase magnetic integrated transformer in one embodiment;

[0022] Figure 9 This is a schematic diagram illustrating the principle of equivalent inductance of the primary excitation inductance of a three-phase magnetic integrated transformer in one embodiment.

[0023] Figure 10 This is a schematic diagram of the common magnetic core structure of a three-phase magnetic integrated transformer in one embodiment;

[0024] Figure 11 This is a schematic diagram of a delta connection of a three-phase magnetic integrated transformer in one embodiment;

[0025] Figure 12 This is a schematic diagram of a Y-connection of a three-phase magnetic integrated transformer in one embodiment;

[0026] Figure 13 This is a schematic diagram of a partial circuit topology of a three-phase magnetic integrated transformer in one embodiment.

[0027] Figure 14 This is a schematic diagram of the principle of three second intermediate column magnetic integrated cores of a three-phase magnetic integrated transformer in one embodiment;

[0028] The diagram is labeled as follows: 100, filter inductor; 111, first magnetic core; 112, second magnetic core; 113, third magnetic core; 114, fourth magnetic core; 115, first center column; 116, insulating pad; 117, magnetic sheet; 121, inductor coil; 200, three-phase transformer; 211, fifth magnetic core; 212, second center column; 221, transformer coil; 2210, primary side; 2211, secondary side; 300, base. Detailed Implementation

[0029] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present invention.

[0030] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the invention or its application or use.

[0031] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0032] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0033] like Figures 1-13As shown, a three-phase magnetic integrated transformer includes a base 300, on which a filter inductor 100 and a three-phase transformer 200 are fixedly installed. The filter inductor 100 is composed of a first magnetic core 111, a second magnetic core 112, a third magnetic core 113, a fourth magnetic core 114, and three inductor coils 121 spliced ​​together by sharing a magnetic core. The three-phase transformer 200 is composed of two fifth magnetic cores 211 and three transformer coils 221 disposed between the two fifth magnetic cores 211.

[0034] The principle of shared magnetic core is due to the fact that the winding direction of the inductor coil 121 in the middle of the filter inductor 100 is opposite to that of the inductor coils 121 on both sides. According to the right-hand rule, the magnetic circuit direction is as follows: Figure 10 As shown, the current phase angles between the three inductors 121 differ by 120°, and the three currents are equal in magnitude. Using trigonometric functions for analysis, the horizontal magnetic flux components are equal in magnitude but opposite in direction and cancel each other out, while the sum of the vertical magnetic flux is "1". This allows for the sharing of magnetic cores, thus saving on the amount of magnetic cores needed.

[0035] In the aforementioned three-phase magnetic integrated transformer, three second intermediate columns 212 are provided on the fifth magnetic core 211, and the transformer coil 221 is configured to be wound on the second intermediate columns 212 in two parts: the primary side 2210 and the secondary side 2211.

[0036] The transformer coil 221 is wound using the sandwich method. The sandwich method refers to the winding of the primary side 2210 in two parts, which are connected in series without interruption, with the secondary side 2211 sandwiched in the middle. The sandwich method can significantly reduce the leakage inductance of the transformer and reduce the impact of the peak voltage caused by the leakage inductance on the withstand voltage of the switching transistor.

[0037] like Figure 11 As shown, the primary side 2210 adopts a delta connection: line voltage = phase voltage. According to Faraday's law, with constant voltage, the number of turns of the primary side 2210 does not increase, and the phase current is reduced by 42%, which significantly saves copper wire usage. At the same time, the transformer adopts a delta connection, with the ends connected sequentially and then connected in parallel with the resonant inductor pins, further reducing the number of product pins and connection points, and improving product reliability. After the delta connection, the magnetizing inductance of the primary side 2210 is the equivalent inductance of this phase inductance and the inductances of the other two phases connected in series and then in parallel. Since the fifth magnetic core 211 has a micro air gap, the permeability of the air is more than 3,000 times different from that of the magnetic core. Thus, the air reluctance is more than 3,000 times that of the magnetic core reluctance, reducing the impact of inconsistent and asymmetrical three-phase magnetic circuit lengths to almost nothing. The three sets of magnetizing inductances are basically the same, which can compensate for the disadvantages of unbalanced current due to asymmetrical three-phase center column.

[0038] The secondary side 2211 client can flexibly adopt a delta connection or a Y-star connection in the PCB printed circuit board design according to the actual situation, such as Figure 12 As shown, a Y-type connection is used: line current = phase current. According to Faraday's law, the voltage is reduced by about 42%, and the number of turns can be reduced by 42%, which greatly saves the amount of copper wire used.

[0039] like Figure 9 As shown, the principle of the equivalent inductance of the primary winding 2210 magnetizing inductor of the transformer is as follows: Let the inductance of the Ap winding before delta connection be L1, the inductance of the Bp winding before delta connection be L2, the inductance of the Cp winding before delta connection be L3, the mutual inductance between the Ap and Bp windings be M1, the mutual inductance between the Bp and Cp windings be M2, and the mutual inductance between the Ap and Cp windings be M3. Then the equivalent inductance after delta connection... After simplification, we get

[0040] Because of the symmetry of the left and right magnetic circuits and the fact that the three transformer coils are the same, the mutual inductances M1 and M2 are basically equal, and the inductances L1 and L3 are basically equal. Therefore, the equivalent inductances LAp and LCp are basically the same. When grinding the magnetic core, the inductance depth of the middle column of the three-column integrated magnetic core can be finely adjusted by testing. This allows the inductance of L2 to be controlled to be basically the same as that of L1 and L3. In this way, the inductance values ​​of the three equivalent inductances LAp, LBp, and LCp are basically the same.

[0041] In the aforementioned three-phase magnetic integrated transformer, the three second intermediate columns 212 are of the same size and are evenly distributed on the fifth magnetic core 211.

[0042] The design of mounting three second central pillars 212 on the fifth magnetic core 211 constitutes a magnetically integrated core, which significantly reduces the core size. The principle of the magnetically integrated core is as follows: Figure 14 As shown, this is because the phase angle of the three coil windings of the transformer differs by 120°, and the magnetic flux at the center point is zero, thus omitting the center column.

[0043] In the aforementioned three-phase magnetic integrated transformer, the first magnetic core 111, the second magnetic core 112, and the third magnetic core 113 are all fixedly mounted with a first central column 115, which is installed in a slot shape.

[0044] The slotted mounting method significantly increases the Ae value of the magnetic core without substantially increasing its volume, thus improving its power handling capability. The slotted shape evolved from a circular core that was cut in half and then elongated to both sides. Figure 5As shown, compared to the circular first central column 115, by only slightly adjusting the dimensions of one side of the magnetic core, a significant increase in the Ae value of the magnetic core is achieved. For example, the central column of the resonant inductor core has a 15*18mm slot, which, relative to a φ15mm diameter, has an area of ​​176.625mm². 2 For a circle, the Ae value increases by 3*15 / 176.625 = 25.5%.

[0045] In the aforementioned three-phase magnetic integrated transformer, an insulating pad 116 is fixedly installed on the first intermediate column 115, and a magnetic sheet 117 is fixedly installed on the insulating pad 116.

[0046] This design employs a segmented air gap, and the inductor coil 121 is wound around the first central post 115 with an enlarged central hole. The segmented air gap is achieved by alternately stacking a long air gap with insulating pads 116 and magnetic sheets 117 to form multiple short air gaps, such as... Figure 6 As shown, the length of each air gap segment is half that of the original long air gap. Because the air gap length is shortened, the range of the edge magnetic flux is reduced, avoiding eddy current losses caused by the edge magnetic flux cutting the winding. The enlarged center hole means that the inner hole of the inductor coil 121 is not tightly attached to the first center post 115. Figure 7 As shown, instead of using the first central column 115, the inductor coil 121 winding is scaled up proportionally to create a certain distance between the inner side of the winding and the first central column 115, preventing edge magnetic flux from cutting the winding, reducing eddy current losses and improving the product's heat dissipation.

[0047] The aforementioned three-phase magnetic integrated transformer has a square base 300 with a hollowed-out center.

[0048] By placing a thermally conductive silicone pad on the bottom of the base 300, the product temperature can be transferred away through the bottom magnetic core surface, greatly improving heat dissipation performance.

[0049] Although specific embodiments of the present invention have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A three-phase magnetic integrated transformer, comprising a base (300), characterized in that: A filter inductor (100) and a three-phase transformer (200) are fixedly installed on the base (300). The filter inductor (100) is composed of a first magnetic core (111), a second magnetic core (112), a third magnetic core (113), a fourth magnetic core (114), and three inductor coils (121) spliced ​​together by sharing a magnetic core. The three-phase transformer (200) is composed of two fifth magnetic cores (211) and three transformer coils (221) arranged between the two fifth magnetic cores (211).

2. A three-phase magnetic integrated transformer according to claim 1, characterized in that: The fifth magnetic core (211) is provided with three second central columns (212), and the transformer coil (221) is configured to have two parts, the primary side (2210) and the secondary side (2211), wound on the second central columns (212).

3. A three-phase magnetic integrated transformer according to claim 2, characterized in that: The three second central pillars (212) are the same size and are evenly distributed on the fifth magnetic core (211).

4. A three-phase magnetic integrated transformer according to claim 1, characterized in that: The first magnetic core (111), the second magnetic core (112) and the third magnetic core (113) are all fixedly mounted with a first central column (115), and the first central column (115) is mounted in a slot shape.

5. A three-phase magnetic integrated transformer according to claim 4, characterized in that: An insulating gasket (116) is fixedly installed on the first central column (115), and a magnetic sheet (117) is fixedly installed on the insulating gasket (116).

6. A three-phase magnetic integrated transformer according to claim 1, characterized in that: The base (300) is square, and the center of the base (300) is hollowed out.

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