Transformer and bidirectional isolated resonant converter

Abstract

The embodiment of the present application provides a transformer and a bidirectional isolated resonant converter, wherein the transformer includes a first side winding, a second side winding and a magnetic core, the magnetic core includes: a winding column, at least one side column and two connecting parts, the first side winding includes: a first side first winding and a first side second winding electrically connected, and the second side winding is located between the first side first winding and the first side second winding. An air gap is provided on the winding column, and the air gap is provided between the second side winding and the first end face of the winding column, and the first side equivalent leakage inductance and the second side equivalent leakage inductance are obtained through the air gap, and the first side equivalent leakage inductance and the second side equivalent leakage inductance are used to realize the first side resonant inductance and the second side resonant inductance of the bidirectional isolated resonant converter, and there is no need to additionally provide the first side resonant inductance and the second side resonant inductance, thereby reducing the overall volume and loss of the magnetic element, thereby also reducing the volume and loss of the bidirectional isolated resonant converter.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of power supply technology, and in particular to a transformer and a bidirectional isolated resonant converter. Background Art

[0002] In bidirectional isolated converters, CLLLC topology is a typical circuit solution. Figure 1a 1 is a circuit schematic diagram of a bidirectional isolated resonant converter. The bidirectional isolated resonant converter includes a first side circuit 110, a second side circuit 120 and a resonant cavity circuit 130, and the resonant cavity circuit 130 is electrically coupled between the first side circuit 110 and the second side circuit 120. The resonant cavity circuit 130 includes a first side resonant capacitor Cr1, a second side resonant capacitor Cr2, three resonant inductors Lr1, Lr2, Lm, and an isolation transformer Tx. The three resonant inductors are respectively a first side resonant inductor Lr1, a parallel resonant inductor Lm, and a second side resonant inductor Lr2.

[0003] Regarding the implementation scheme of the magnetic elements in the bidirectional isolated resonant converter, the first scheme is that the first side resonant inductor Lr1 and the second side resonant inductor Lr2 are two independent magnetic elements, respectively, and the transformer Tx and the parallel resonant inductor Lm are integrated together to form a magnetic element. The bidirectional isolated resonant converter using this scheme includes a total of three independent magnetic elements. Due to the large number of magnetic elements, the size and loss of the magnetic elements are relatively large, which makes the total volume and loss of the resonant converter larger, and the cost is also relatively high.

[0004] The second solution is that the resonant inductors Lr1, Lr2 and the transformer Tx share part of the magnetic core to achieve partial integration of the magnetic core, such as Figure 1b Compared with the first solution, the second solution can reduce the overall size of the magnetic component. However, in this solution, the resonant inductors Lr1, Lr2 and the transformer Tx only share part of the magnetic core, and the windings of the first-side resonant inductor Lr1 and the second-side resonant inductor Lr2 still need to be set separately. Therefore, the overall integration of the magnetic component is still not high, and the loss reduction effect is still not significant enough. Summary of the invention

[0005] Embodiments of the present application provide a transformer and a bidirectional isolated resonant converter.

[0006] In a first aspect, an embodiment of the present application provides a transformer, comprising: a first side winding, a second side winding and a magnetic core;

[0007] The magnetic core comprises: a winding column, at least one side column and two connecting parts;

[0008] The two ends of the winding column are respectively connected to the at least one side column through the two connecting parts;

[0009] The first side winding includes: a first side first winding and a first side second winding electrically connected;

[0010] The second side winding is located between the first side first winding and the first side second winding, and the second side winding is spaced apart from the first side first winding by a first preset distance along the axial direction of the winding column, and the second side winding is spaced apart from the first side second winding by a second preset distance along the axial direction of the winding column, and the first side first winding, the first side second winding and the second side winding are all wound around the winding column;

[0011] A first air gap is arranged on the winding post, wherein the first air gap is arranged between the second side winding and the first end surface of the winding post.

[0012] Optionally, the first air gap is used to obtain a first-side equivalent leakage inductance and a second-side equivalent leakage inductance, and the first-side equivalent leakage inductance and the second-side equivalent leakage inductance are used to realize a first-side resonant inductance and a second-side resonant inductance of a bidirectional isolated resonant converter.

[0013] Optionally, the first air gap is arranged between the second side winding and the first side first winding.

[0014] Optionally, a second air gap is further provided on the winding post, and the second air gap is provided between the second side winding and the second end face of the winding post, wherein the second end face of the winding post is arranged opposite to the first end face.

[0015] Optionally, the second air gap is arranged between the second side winding and the first side second winding.

[0016] Optionally, the first winding on the first side and the second winding on the first side are symmetrically distributed relative to the winding on the second side, and the first air gap and the second air gap are symmetrically distributed relative to the winding on the second side.

[0017] Optionally, the transformer further comprises: a first auxiliary magnet and a second auxiliary magnet;

[0018] The first auxiliary magnet is disposed between the first-side first winding and the second-side winding, and the second auxiliary magnet is disposed between the first-side second winding and the second-side winding.

[0019] Optionally, the first auxiliary magnet and the second auxiliary magnet are both arranged between the first air gap and the second air gap.

[0020] Optionally, both the first auxiliary magnet and the second auxiliary magnet are magnetic sheets with arc-shaped ends.

[0021] Optionally, the first auxiliary magnet and the second auxiliary magnet are symmetrically distributed relative to the second side winding.

[0022] Optionally, the first auxiliary magnet and the second auxiliary magnet are both separate components, and the first auxiliary magnet and the second auxiliary magnet are fixed to a cavity of a winding frame.

[0023] Optionally, the first auxiliary magnet and the second auxiliary magnet are respectively formed integrally with at least a portion of the winding rod.

[0024] Optionally, a third air gap is provided on the winding rod, and the third air gap is located between the first auxiliary magnet and the second auxiliary magnet.

[0025] Optionally, the at least one side column includes two side columns, and the winding column is located between the two side columns.

[0026] In a second aspect, an embodiment of the present application provides a bidirectional isolated resonant converter, comprising: a first side circuit, a second side circuit and a resonant cavity circuit, wherein the resonant cavity circuit is electrically coupled between the first side circuit and the second side circuit;

[0027] The resonant cavity circuit comprises a first-side resonant capacitor, a second-side resonant capacitor and a transformer as described in any one of the first aspects;

[0028] The transformer is electrically connected to the first-side resonant capacitor and the second-side resonant capacitor.

[0029] The embodiment of the present application provides a transformer and a bidirectional isolated resonant converter. In the transformer, an air gap is provided on the winding column, and the air gap is provided between the second side winding and the first end face of the winding column. The first side equivalent leakage inductance and the second side equivalent leakage inductance are obtained through the air gap, and the first side equivalent leakage inductance and the second side equivalent leakage inductance are used to realize the first side resonant inductance and the second side resonant inductance of the bidirectional isolated resonant converter, and there is no need to additionally provide the first side resonant inductance and the second side resonant inductance, thereby reducing the overall volume and loss of the magnetic element, thereby improving the integration of the bidirectional isolated resonant converter, and thus reducing the volume and loss of the bidirectional isolated resonant converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0031] Figure 1aIt is a circuit schematic diagram of a bidirectional isolated resonant converter;

[0032] Figure 1b A magnetic integration solution for a transformer and a resonant inductor;

[0033] Figure 2a A schematic diagram of the structure of a transformer provided in one embodiment of the present application;

[0034] Figure 2b for Figure 2a Schematic diagram of the three-dimensional structure of the transformer;

[0035] Figure 2c for Figure 2a A front view of the magnetic core of the transformer;

[0036] Figure 2d for Figure 2a A three-dimensional diagram of the magnetic core of the transformer;

[0037] Figure 2e for Figure 2a Exploded view of the transformer's magnetic core;

[0038] Figure 3 A schematic diagram of leakage flux distribution provided in an embodiment of the present application;

[0039] Figure 4 A diagram showing the relationship between the position of the first air gap and the first-side equivalent leakage inductance and the second-side equivalent leakage inductance provided in one embodiment of the present application;

[0040] Figure 5a An equivalent circuit schematic diagram of a transformer provided in an embodiment of the present application, showing the inductance of the first-side equivalent leakage inductance and the second-side equivalent leakage inductance;

[0041] Figure 5b The equivalent circuit schematic diagram of the transformer provided according to the related art shows the inductance of the first side equivalent leakage inductance and the second side equivalent leakage inductance;

[0042] Figure 6a-6c A circuit schematic diagram for obtaining inductance parameters provided in an embodiment of the present application;

[0043] Figure 7a A schematic diagram of the structure of a transformer provided in one embodiment of the present application;

[0044] Figure 7b for Figure 7a Schematic diagram of the three-dimensional structure of the transformer;

[0045] Figure 7c for Figure 7a A three-dimensional diagram of the magnetic core of the transformer;

[0046] Figure 7d for Figure 7a Exploded view of the transformer's magnetic core;

[0047] Figure 8a A schematic diagram of the three-dimensional structure of a transformer provided in one embodiment of the present application;

[0048] Figure 8b for Figure 8a A front view of the magnetic core of the transformer;

[0049] Figure 8c for Figure 8a A three-dimensional diagram of the magnetic core of the transformer;

[0050] Figure 8d for Figure 8a Exploded view of the transformer’s magnetic core. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0052] Figure 2a A schematic diagram of the structure of a transformer provided in an embodiment of the present application is shown in FIG. Figure 2b for Figure 2a Schematic diagram of the three-dimensional structure of the transformer. Figure 2c for Figure 2a The front view of the transformer core. Figure 2d for Figure 2a A three-dimensional diagram of the transformer's magnetic core. Figure 2e for Figure 2a Exploded diagram of the transformer core. Figure 2a-2b As shown, the transformer includes: a first side winding 310, a second side winding 320 and a magnetic core 330. It should be noted that, in addition to Figure 2a-2b In addition to the first side winding 310 , the second side winding 320 and the magnetic core 330 shown, other components such as a winding frame and a clamp may also be included, and the present application does not limit this.

[0053] Among them, Figure 2c-Figure 2eAs shown, the magnetic core 330 includes: a winding column 331, at least one side column 332, and two connecting parts 333. Both ends of the winding column 331 are respectively connected to at least one side column 332 through the two connecting parts 333. In this embodiment, the number of side columns 332 is two, and they are respectively located at the left and right ends of the two connecting parts 333. The winding column 331 is located between the two side columns 332, and the entire magnetic core 330 is in the shape of a Chinese character 'Ri'. However, in other embodiments, the number of side columns 332 can be one, and in this case, the entire magnetic core 330 is in the shape of a square.

[0054] As Figure 2a , Figure 2b shown, the first-side winding 310 includes: a first-side first winding 311 and a first-side second winding 312 that are electrically connected. The second-side winding 320 is located between the first-side first winding 311 and the first-side second winding 312, and the second-side winding 320 is axially spaced from the first-side first winding 311 by a first preset distance L1 along the winding column 331, and the second-side winding 320 is axially spaced from the first-side second winding 312 by a second preset distance L2 along the winding column 331. The first-side first winding 311, the first-side second winding 312, and the second-side winding 320 are all wound around the winding column 331. In this embodiment, the first-side first winding 311 and the first-side second winding 312 can be connected in series or in parallel.

[0055] A first air gap S1 is provided on the winding column 331, where the first air gap S1 is provided between the second-side winding 320 and the first end face H1 of the winding column 331.

[0056] For Figure 2a , Figure 2b the transformer shown, the first-side first winding 311, the second-side winding 320, and the first-side second winding 312 are wound around the winding column 331 in sequence along the axial direction of the winding column 331. Among them, the first-side first winding 311 and the second-side winding 320 are spaced by a first preset distance L1, and the second-side winding 320 and the first-side second winding 312 are spaced by a second preset distance L2. The first preset distance and the second preset distance can be equal or unequal. When the first preset distance L1 and the second preset distance L2 are equal, the first-side first winding 311 and the first-side second winding 312 are symmetrically distributed relative to the second-side winding 320.

[0057] A first air gap S1 is provided on the winding column 331, and the first air gap S1 is provided between the second-side winding 320 and the first end face H1 of the winding column 331. Among them, the first end face H1 of the winding column 331 is the plane where the winding column 331 is connected to one of the two connecting parts 333.

[0058] For example Figure 2a , Figure 2bAs shown, d is the distance between the first air gap S1 and the middle position of the second side winding 320, D1 is the distance between the upper edge of the second side winding 320 and the middle position of the second side winding 320, D2 is the distance between the lower edge of the first side first winding 311 and the middle position of the second side winding 320, and D3 is the distance between the first end surface H1 of the winding column 331 and the middle position of the second side winding 320. The position of the first air gap S1 satisfies D1. <d<D3。

[0059] Figure 2a , Figure 2b The transformer shown in the figure can obtain the first side equivalent leakage inductance and the second side equivalent leakage inductance by setting the first air gap S1 between the second side winding 320 and the first end surface H1 of the winding column 331, and utilize the first side equivalent leakage inductance and the second side equivalent leakage inductance to realize the first side resonant inductance and the second side resonant inductance of the bidirectional isolated resonant converter, without the need to additionally set up the windings of the first side resonant inductance and the second side resonant inductance, that is, to realize the full integration of the first side resonant inductance, the second side resonant inductance, the parallel resonant inductance and the transformer, thereby reducing the overall volume and loss of the magnetic components, thereby also reducing the volume and loss of the bidirectional isolated resonant converter.

[0060] Moreover, on the winding column 331, adjusting the position of the first air gap S1 can adjust the size of the first side equivalent leakage inductance and the second side equivalent leakage inductance, thereby adjusting the size of the first side resonant inductance and the second side resonant inductance to meet the requirements for the first side resonant inductance and the second side resonant inductance.

[0061] In some possible embodiments, continue to refer to Figure 2a , Figure 2b A second air gap S2 is also provided on the winding post 331, wherein the second air gap S2 is located between the second side winding 320 and the second end surface H2 of the winding post 331. Figure 2c-Figure 2e As shown, the second end surface H2 is a plane where the winding post 331 is connected to the other connection portion 333 of the two connection portions 333 . On the winding post 331 , the second end surface H2 and the first end surface H1 are arranged opposite to each other.

[0062] Figure 3 A schematic diagram of leakage flux distribution provided in an embodiment of the present application, wherein: Figure 3 (a) shows the distribution of leakage flux; Figure 3 (b) is the magnetic field intensity generated by the first side current flowing through the first side winding 310 and the second side current flowing through the second side winding 320, and the magnetic field energy corresponds to the sum of the first side equivalent leakage inductance and the second side equivalent leakage inductance; Figure 3 (c) is the magnetic field intensity generated by the first side current flowing through the first side winding 310, and the magnetic field energy corresponds to the magnitude of the first side equivalent leakage inductance; Figure 3In (d), it is the magnetic field intensity generated by the second-side current flowing through the second-side winding 320, and its magnetic field energy corresponds to the magnitude of the second-side equivalent leakage inductance.

[0063] As Figure 3 shown in (a) thereof, 51 is the leakage magnetic flux of the first-side winding 310, 52 is the leakage magnetic flux of the second-side winding 320, and 53 is the mutual magnetic flux between the first-side winding 310 and the second-side winding 320, where the direction of the arrow indicates the direction of the magnetic flux.

[0064] From Figure 3 it can be known that by providing a first air gap S1 between the second-side winding 320 on the winding post 331 and the first end face H1 of the winding post 331, and providing a second air gap S2 between the second-side winding 320 and the second end face H2 of the winding post 331, the distribution of the first-side leakage inductance magnetic flux and the second-side leakage inductance magnetic flux can be made more balanced, which is beneficial to reducing the core loss.

[0065] Among them, in order to make the distribution of the first-side leakage inductance magnetic flux and the second-side leakage inductance magnetic flux more balanced, in some embodiments, on the winding post 331, the second air gap S2 can be provided between the second-side winding 320 and the first-side second winding 312, and the first air gap S1 and the second air gap S2 are symmetrically distributed relative to the second-side winding 320.

[0066] It should be noted that when only one air gap is provided on the winding post 331, that is, only the first air gap S1 is provided, the first air gap S1 can also be provided between the second-side winding 320 and the second end face H2 of the winding post 331.

[0067] Figure 4 This is a relationship diagram between the position of the first air gap provided by an embodiment of the present application and the first-side equivalent leakage inductance and the second-side equivalent leakage inductance. As Figure 4 shown, when the first air gap S1 moves from the middle position of the second-side winding 320 to the first end face H1, the leakage magnetic flux 51 formed by the first-side current in the first-side winding 310 will decrease, that is, the first-side equivalent leakage inductance L k1 decreases, and the leakage magnetic flux 52 formed by the second-side current in the second-side winding 320 will increase, that is, the second-side equivalent leakage inductance L k2 increases.

[0068] Moreover, from Figure 4 it can be known that when 0 < d < D1, the position of the first air gap S1 has a certain regulating effect on the second-side equivalent leakage inductance L k2 , but the regulating effect on the first-side equivalent leakage inductance L k1 is limited. When D2 < d < D3, the position of the first air gap S1 has a certain regulating effect on the first-side equivalent leakage inductance L k1 , but the regulating effect on the second-side equivalent leakage inductance L k2 is limited.

[0069] Therefore, in some embodiments, the position of the first air gap S1 is D1 < d < D2, that is, it is arranged between the upper edge of the second-side winding 320 and the lower edge of the first winding 311 on the first side. At this time, the position of the first air gap S1 has a relatively high sensitivity to the relationship with the equivalent leakage inductance L k1 on the first side and the equivalent leakage inductance L k2 on the second side. It is relatively easy to adjust the equivalent leakage inductance L k1 on the first side and the equivalent leakage inductance L k2 on the second side. Moreover, it is relatively easy to balance the equivalent leakage inductance L k1 on the first side and the equivalent leakage inductance L k2 on the second side. That is, it is relatively easy to balance the first-side resonant inductance and the second-side resonant inductance obtained after equivalence to meet the application requirements.

[0070] Next, the equivalent leakage inductance generated when the first air gap S1 in the embodiment of the present application is arranged between the upper edge of the second-side winding 320 and the lower edge of the first winding 311 on the first side is compared with the equivalent leakage inductance generated when the air gap is arranged at the middle position of the second-side winding 320 in the related art.

[0071] Among them, the number of turns of the first-side winding 310 is N1 = 8 turns, the number of turns of the first winding 311 on the first side is 4 turns, the number of turns of the second winding 312 on the first side is 4 turns, the first winding 311 on the first side and the second winding 312 on the first side are connected in series, the number of turns of the second-side winding 320 is N2 = 6 turns, and the turns ratio is n = N2 / N1 = 6 / 8. D1 = 4.0 mm, D2 = 10 mm, d = 7.0 mm.

[0072] As Figure 5a shown, when the first air gap S1 is arranged between the upper edge of the second-side winding 320 and the lower edge of the first winding 311 on the first side, the equivalent leakage inductance L k1 on the first side = 1.9 uH, the equivalent leakage inductance L k2 on the second side = 1.3 uH, and the magnetizing inductance Lm = 23 uH. That is, the first-side resonant inductance Lr1 = 1.9 uH, the second-side resonant inductance Lr2 = 1.3 uH, and the parallel resonant inductance Lm = 23 uH.

[0073] As a comparison with the related art, the leakage inductance distribution when the air gap is arranged at the middle position of the second-side winding 320, that is, when d = 0, is synchronously compared. As Figure 5b shown, the equivalent leakage inductance L k1 on the first side = 4.0 uH, the equivalent leakage inductance L k2 on the second side = 0.1 uH, and the magnetizing inductance Lm = 23 uH. At this time, the equivalent leakage inductance on the first side is too large, and the equivalent leakage inductance on the second side is too small.

[0074] In Figure 1a In the circuit topology of the CLLLC shown, the typical requirements for the first side resonant inductor Lr1 and the second side resonant inductor Lr2 are Lr1 ≥ 5% * Lm, Lr2 ≥ 5% * Lm * n 2 Therefore, in the embodiment of the present application, the equivalent leakage inductance can meet the application requirements of CLLLC; however, in the related art, the air gap is set in the middle position of the second side winding 320, that is, when d=0, the application requirements of the first side resonant inductor Lr1 and the second side resonant inductor Lr2 cannot be met.

[0075] Below, reference Figure 6a-6c , to obtain the first side equivalent leakage inductance L k1 , the second side equivalent leakage inductance L k2 The method of using the magnetizing inductance Lm is as follows:

[0076] First, the equivalent circuit Figure 6a As shown, the second side winding 320 is short-circuited to obtain the inductance of the first side winding 310, which is recorded as La. Then, as Figure 6b As shown, the second side winding 320 is open-circuited to obtain the inductance of the first side winding 310, which is recorded as Lb. Figure 6c As shown, the first side winding 310 is short-circuited to obtain the inductance of the second side winding 320, which is recorded as Lc. The equation group is obtained as follows:

[0077]

[0078] Among them, L k1 is the equivalent leakage inductance of the first side, L k2 is the equivalent leakage inductance of the second side, Lm is the magnetizing inductance, and the symbol “ / / ” indicates “parallel connection”. Solving the above equations yields:

[0079]

[0080] L k1 =L b -L m

[0081]

[0082] In order to increase the leakage inductance of the transformer, it is usually necessary to increase the first preset distance L1 between the first side first winding 311 and the second side winding 320, and the second preset distance L2 between the second side winding 320 and the first side second winding 312, which will increase the volume of the transformer. Therefore, in order to further reduce the volume of the transformer, the present application proposes to set an auxiliary magnet on the transformer based on any of the above embodiments. Exemplarily, Figure 7a A schematic diagram of the structure of a transformer provided in an embodiment of the present application is shown in FIG. Figure 7b for Figure 7aSchematic diagram of the three-dimensional structure of the transformer. Figure 7c for Figure 7a A three-dimensional diagram of the transformer's magnetic core. Figure 7d for Figure 7a Exploded diagram of the transformer core. Figure 7a-7d As shown, the transformer further includes: a first auxiliary magnet P1 and a second auxiliary magnet P2.

[0083] Among them, Figure 7a-7d As shown, the first auxiliary magnet P1 is disposed between the first-side first winding 311 and the second-side winding 320 , and the second auxiliary magnet P2 is disposed between the first-side second winding 312 and the second-side winding 320 .

[0084] for Figure 7a-Figure 7b The transformer shown is described by taking the first auxiliary magnet P1 as an example. The first auxiliary magnet P1 is arranged between the first side first winding 311 and the second side winding 320. Since the first auxiliary magnet P1 is a magnetic core component, the first side equivalent leakage inductance can be increased, so that the large leakage inductance can be maintained without increasing the distance between the first side first winding 311 and the second side winding 320. Therefore, while maintaining the same leakage inductance, the distance between the first side first winding 311 and the second side winding 320 can be reduced; similarly, the second auxiliary magnet P2 can reduce the distance between the first side second winding 312 and the second side winding 320, thereby reducing the volume of the transformer.

[0085] In some embodiments, continue to refer to Figure 7c and Figure 7d The first auxiliary magnet P1 and the second auxiliary magnet P2 are both magnetic pieces with arc-shaped ends. The magnetic core and the auxiliary magnets can both be made of ferrite materials.

[0086] In some embodiments, continue to refer to Figure 7a-7c The first auxiliary magnet P1 and the second auxiliary magnet P2 are symmetrically distributed relative to the second side winding 320 .

[0087] In some embodiments, continue to refer to Figure 7d The first auxiliary magnet P1 and the second auxiliary magnet P2 are both discrete components, and the first auxiliary magnet P1 and the second auxiliary magnet P2 are fixed to a cavity of a winding frame. Using discrete components can simplify the complexity of each component and reduce the difficulty of molding. In other embodiments, the shape, quantity and material of the auxiliary magnets can be selected in other ways.

[0088] Figure 8a This is a schematic diagram of the three-dimensional structure of a transformer provided in an embodiment of the present application. Figure 8b for Figure 8a The front view of the transformer core. Figure 8c for Figure 8aA three-dimensional diagram of the transformer's magnetic core. Figure 8d for Figure 8a Exploded view of the transformer’s magnetic core.

[0089] In some embodiments, Figure 8a-8d As shown, the first auxiliary magnet P1 and the second auxiliary magnet P2 are both disposed between the first air gap S1 and the second air gap S2. This embodiment is applicable to applications where the equivalent leakage inductance on the second side needs to be larger and the equivalent leakage inductance on the first side needs to be smaller.

[0090] like Figure 8b , Figure 8c As shown, a third air gap S3 is provided on the winding post 331, and the third air gap S3 is located between the first auxiliary magnet P1 and the second auxiliary magnet P2. In this embodiment, the provision of the third air gap S3 can increase the magnetic resistance of the leakage flux path of the second side winding 320, thereby reducing the equivalent leakage inductance of the second side, and playing a role in more flexible regulation and control of the leakage inductance.

[0091] In some embodiments, Figure 8b , Figure 8c As shown, the third air gap S3 is located in the middle of the second side winding 320 .

[0092] In some embodiments, Figure 8d As shown, the first auxiliary magnet P1 and the second auxiliary magnet P2 are respectively formed integrally with at least part of the winding rod 331. This can better control the position of the first auxiliary magnet P1 and the second auxiliary magnet P2 relative to the magnetic core 330, reduce the number of magnetic core components, and simplify the complexity of the transformer process.

[0093] Based on the technical concept of the present application, the embodiment of the present application also provides a bidirectional isolated resonant converter, such as Figure 1a As shown, the bidirectional isolated resonant converter includes: a first side circuit 110, a second side circuit 120 and a resonant cavity circuit 130, wherein the resonant cavity circuit 130 is electrically coupled between the first side circuit 110 and the second side circuit 120. The resonant cavity circuit 130 includes a first side resonant capacitor Cr1, a second side resonant capacitor Cr2 and a transformer as described in any of the above embodiments. The transformer is electrically connected to the first side resonant capacitor Cr1 and the second side resonant capacitor Cr2.

[0094] By applying the transformer in the above embodiment to Figure 1aIn the bidirectional isolated resonant converter, the first side equivalent leakage inductance and the second side equivalent leakage inductance are obtained by controlling the setting position of the air gap in the transformer, and the first side equivalent leakage inductance and the second side equivalent leakage inductance are used to realize the first side resonant inductance and the second side resonant inductance of the bidirectional isolated resonant converter, without the need to additionally set the first side resonant inductance and the second side resonant inductance, that is, the first side resonant inductance, the second side resonant inductance, the parallel resonant inductance and the transformer are fully integrated, thereby reducing the overall volume and loss of the magnetic components, thereby also reducing the volume and loss of the bidirectional isolated resonant converter.

[0095] The terms "first", "second", "third", "fourth" and the like (if any) in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0096] In addition, it should be noted that, in the present invention, unless otherwise clearly stipulated and limited, the terms "connection", "connected", etc. should be understood in a broad sense. For example, it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. It can be the internal connection of two elements or the interaction relationship between two elements. Unless otherwise clearly defined, ordinary technicians in this field can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0097] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A transformer, It is characterized in that include: A first side winding, a second side winding and a magnetic core; The magnetic core comprises: a winding column, at least one side column and two connecting parts; The two ends of the winding column are respectively connected to the at least one side column through the two connecting parts; The first side winding includes: a first side first winding and a first side second winding electrically connected; The second side winding is located between the first side first winding and the first side second winding, and the second side winding is spaced apart from the first side first winding by a first preset distance along the axial direction of the winding column, and the second side winding is spaced apart from the first side second winding by a second preset distance along the axial direction of the winding column, and the first side first winding, the first side second winding and the second side winding are all wound around the winding column; A first air gap is provided on the winding post, wherein the first air gap is provided between the second side winding and the first end surface of the winding post; The first air gap is used to obtain the first-side equivalent leakage inductance and the second-side equivalent leakage inductance, and the first-side equivalent leakage inductance and the second-side equivalent leakage inductance are used to realize the first-side resonant inductance and the second-side resonant inductance of the bidirectional isolated resonant converter. By adjusting the position of the first air gap, the size of the first-side equivalent leakage inductance and the second-side equivalent leakage inductance can be adjusted, thereby adjusting the size of the first-side resonant inductance and the second-side resonant inductance.

2. The transformer according to claim 1, It is characterized in that The first air gap is disposed between the second side winding and the first side first winding.

3. The transformer according to claim 1 or 2, It is characterized in that The winding post is also provided with a second air gap, and the second air gap is provided between the second side winding and the second end face of the winding post, wherein the second end face of the winding post is arranged opposite to the first end face.

4. The transformer according to claim 3, It is characterized in that The second air gap is disposed between the second side winding and the first side second winding.

5. The transformer according to claim 3, It is characterized in that The first side first winding and the first side second winding are symmetrically distributed relative to the second side winding, and the first air gap and the second air gap are symmetrically distributed relative to the second side winding.

6. The transformer according to claim 3, It is characterized in that The transformer further comprises: a first auxiliary magnet and a second auxiliary magnet; The first auxiliary magnet is disposed between the first-side first winding and the second-side winding, and the second auxiliary magnet is disposed between the first-side second winding and the second-side winding.

7. The transformer according to claim 6, It is characterized in that The first auxiliary magnet and the second auxiliary magnet are both disposed between the first air gap and the second air gap.

8. The transformer according to claim 6, It is characterized in that The first auxiliary magnet and the second auxiliary magnet are both magnetic sheets with arc-shaped ends.

9. The transformer according to claim 6, It is characterized in that The first auxiliary magnet and the second auxiliary magnet are symmetrically distributed relative to the second side winding.

10. The transformer according to claim 6, It is characterized in that The first auxiliary magnet and the second auxiliary magnet are both separate components, and the first auxiliary magnet and the second auxiliary magnet are fixed in a cavity of a winding frame.

11. The transformer according to claim 6, It is characterized in that The first auxiliary magnet and the second auxiliary magnet are respectively formed integrally with at least a portion of the winding post.

12. The transformer according to any one of claims 6 to 11, It is characterized in that A third air gap is provided on the winding column, and the third air gap is located between the first auxiliary magnet and the second auxiliary magnet.

13. The transformer according to claim 1 or 2, It is characterized in that The at least one side column includes two side columns, and the winding column is located between the two side columns.

14. A bidirectional isolated resonant converter, It is characterized in that include: A first side circuit, a second side circuit and a resonant cavity circuit, wherein the resonant cavity circuit is electrically coupled between the first side circuit and the second side circuit; The resonant cavity circuit comprises a first side resonant capacitor, a second side resonant capacitor and a transformer as claimed in any one of claims 1 to 13; The transformer is electrically connected to the first-side resonant capacitor and the second-side resonant capacitor.

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