CN117747270A - Medium voltage multiport transformer and medium voltage multiport ac coupling converter - Google Patents

Abstract

The invention provides a medium-voltage multiport transformer and a medium-voltage multiport alternating current coupling converter, which relate to the technical field of transformers and comprise: a magnetic core, a plurality of windings and m ports; m is greater than or equal to 3; the m ports include: at least one medium pressure port and at least one low pressure port; each winding is wound on the magnetic core respectively; the windings are respectively as follows: a medium voltage winding connected to the medium voltage port, and a low voltage winding connected to the low voltage port; the medium-voltage windings are independently arranged in the corresponding medium-voltage winding areas so as to meet corresponding insulation requirements with other devices. The invention can provide a transformer with medium voltage ports meeting corresponding insulation requirements, and the number of the ports is more than or equal to 3.

Description

Medium voltage multiport transformer and medium voltage multiport ac coupling converter

Technical Field

The invention relates to the technical field of transformers, in particular to a medium-voltage multiport transformer and a medium-voltage multiport alternating current coupling converter.

Background

A transformer is a device that changes an ac voltage using the principle of electromagnetic induction. The current transformers include medium voltage two-port transformers having medium voltage ports capable of meeting corresponding insulation requirements, but only two ports, and multi-port transformers having ports greater than or equal to 3, but no medium voltage ports.

Therefore, how to provide a transformer with medium voltage ports capable of meeting the corresponding insulation requirements and with the number of ports being greater than or equal to 3 is a technical problem to be solved.

Disclosure of Invention

The invention provides a medium-voltage multi-port transformer and a medium-voltage multi-port alternating current coupling converter, wherein the medium-voltage multi-port transformer is provided with medium-voltage ports which can meet corresponding insulation requirements, and the number of the ports is more than or equal to 3.

The technical scheme of the invention is as follows:

the invention provides a medium voltage multiport transformer, comprising: a magnetic core, a plurality of windings and m ports; m is greater than or equal to 3;

the m ports include: at least one medium pressure port and at least one low pressure port;

each winding is wound on the magnetic core respectively;

each winding is respectively as follows: a medium voltage winding connected to the medium voltage port, and a low voltage winding connected to the low voltage port;

the medium-voltage windings are independently arranged in the corresponding medium-voltage winding areas so as to meet corresponding insulation requirements with other devices.

Optionally, in the medium-voltage winding area, solid insulation is formed through a casting process.

Optionally, the solid insulation has an umbrella skirt structure;

the other outer surfaces of the solid insulation except the outer surface of the umbrella skirt structure are surrounded by corresponding shielding layers.

Optionally, a curved surface structure is adopted at the joint of the shielding layer and the umbrella skirt structure.

Optionally, the medium voltage multiport transformer adopts a single winding column structure, a double winding column structure or a multi-winding column structure.

Optionally, when the medium voltage winding and the low voltage winding are simultaneously arranged on the same winding column, the medium voltage winding is wound on the outer side of the low voltage winding.

Optionally, when the number of the low-voltage windings is greater than or equal to 2, all the medium-voltage windings and part of the low-voltage windings are placed in the corresponding solid insulation by a casting process.

Optionally, all the medium voltage windings and all the low voltage windings are placed in the corresponding solid insulation by a casting process.

Optionally, all the medium voltage windings, all the low voltage windings, and the magnetic core are placed in the corresponding solid insulation by a casting process.

Optionally, when the number of the medium voltage ports is equal to 1, the wire outlet direction of the medium voltage winding is set differently from the wire outlet direction of the low voltage winding.

Optionally, when the number of the medium voltage ports is greater than or equal to 2, different wire outlet directions of the medium voltage windings connected by different medium voltage ports are set differently.

Optionally, the number of windings connected to any one of the ports is greater than or equal to 1;

when the number of windings connected with the port is larger than 1, the windings connected with the port are connected in series-parallel.

The invention also provides a medium voltage multi-port ac coupling converter comprising: n medium voltage multiport transformers as described above, and n×m conversion circuits; n is greater than or equal to 1; the m is the port number of the medium-voltage multi-port transformer;

each port of the medium voltage multi-port transformer is connected to a corresponding power supply or load through a corresponding conversion circuit.

Optionally, each low-voltage port of the medium-voltage multi-port transformer is output independently through a corresponding transformation circuit, and each medium-voltage port of the medium-voltage multi-port transformer is cascaded through a corresponding transformation circuit.

Optionally, the conversion circuit to which a medium voltage port of the medium voltage multi-port transformer is connected includes: the AC/DC conversion circuit and the DC/AC conversion circuit are connected on the direct current sides;

the conversion circuit to which the low-voltage port of the medium-voltage multiport transformer is connected includes: an AC/DC conversion circuit.

The invention adopts the technical scheme that the medium-voltage multiport transformer comprises: and the medium-voltage windings connected with the medium-voltage ports in the ports are independently arranged in the corresponding medium-voltage winding areas, so that the medium-voltage windings and other devices meet corresponding insulation requirements. It can be seen that the present invention can provide a transformer having medium voltage ports satisfying the corresponding insulation requirements, and the number of ports is greater than or equal to 3.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of a medium voltage multi-port transformer according to an embodiment of the present invention;

fig. 2 is a schematic structural diagram of another medium voltage multi-port transformer according to an embodiment of the present invention;

FIG. 3 is a schematic illustration of an insulation casting of a medium voltage winding corresponding to FIG. 2, provided in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view of a shielding layer corresponding to FIG. 3 provided by an embodiment of the present invention;

FIG. 5 is a schematic illustration of an insulation casting of a medium voltage winding and a portion of a low voltage winding corresponding to FIG. 2, provided in accordance with an embodiment of the present invention;

FIG. 6 is a schematic illustration of an insulation casting of a medium voltage winding and all low voltage windings corresponding to FIG. 2 provided in accordance with an embodiment of the present invention;

FIG. 7 is a schematic illustration of a medium voltage winding, all low voltage windings and core insulation casting corresponding to FIG. 2 provided in accordance with an embodiment of the present invention;

fig. 8 is a schematic structural diagram of another medium voltage multi-port transformer according to an embodiment of the present invention;

fig. 9 is a schematic structural diagram of a medium voltage multi-port ac-coupled converter according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

Current transformers include medium voltage two port transformers and multi port transformers. The medium-voltage two-port transformer is provided with medium-voltage ports capable of meeting corresponding insulation requirements, but the number of the ports is only two, for example, the medium-voltage low-frequency transformer is mainly applied to a power frequency high-power conversion system, and is generally single-phase or three-phase, the high-voltage winding and the low-voltage winding meet corresponding insulation requirements, namely, medium-voltage insulation can be realized, and the number of the ports is two. The multiport transformer has a port number greater than or equal to 3, but does not have medium voltage ports, such as a multiport medium-high frequency transformer, and has a port number greater than or equal to 3, and is mainly applied to a medium-high frequency low power ac coupling system to realize power transmission among multiple ports, and is generally a low voltage system.

Based on the above, the invention provides a medium-voltage multi-port transformer and a medium-voltage multi-port alternating current coupling converter, wherein the medium-voltage multi-port transformer has medium-voltage ports which can meet corresponding insulation requirements, and the number of the ports is more than or equal to 3. The technical scheme of the invention is described in detail below with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a medium voltage multi-port transformer according to an embodiment of the present invention. As shown in fig. 1, the present medium voltage multiport transformer comprises: a magnetic core 11, a plurality of windings 12 (3 in fig. 1) and m ports 13 (3 in fig. 1), m being greater than or equal to 3.

The m ports 13 include: at least one medium pressure port and at least one low pressure port.

Each winding 12 is wound around the core 11.

Each winding 12 is respectively: a medium voltage winding connected to the medium voltage port, and a low voltage winding connected to the low voltage port.

The medium-voltage windings are independently arranged in the corresponding medium-voltage winding areas so as to meet corresponding insulation requirements with other devices.

Specifically, the medium-voltage multiport transformer in the embodiment of the present invention may be an intermediate-frequency transformer capable of implementing medium-high frequency application, that is, a medium-high frequency and medium-voltage multiport transformer, where the winding 12 may be a high-frequency electromagnetic wire or foil winding, and the magnetic core 11 may be ferrite, amorphous or nanocrystalline, so that intermediate-frequency loss of the winding 12 and the magnetic core 11 may be reduced. It should be noted that, in the IEC 60038:2009 standard, a voltage range corresponding to the medium voltage is defined to be 1kV to 35kV, and in the embodiment of the present invention, the voltage range corresponding to the medium voltage may be 3.3kV to 35kV, so that the embodiment of the present invention may be applied to a medium voltage distribution grid. And, the frequency range corresponding to the intermediate frequency in the embodiment of the invention can be 1kHz to 100kH _Z 。

The medium voltage port may in particular be used for connecting an external medium voltage power electronic converter; in the embodiment of the invention, the main insulation design is performed by adopting solid insulation, and the leakage inductance of the transformer is not negligible due to the reserved thick insulation distance near the medium-voltage related winding, and can be used as a part of the external resonance inductance of the resonance type converter. And the low-voltage port can be particularly used for being connected with an external low-voltage power electronic converter, and the application of the low-voltage power electronic converter comprises a low-voltage energy storage device, a photovoltaic inverter, a charging pile, a hydrogen production power supply or the like.

The plurality of windings 12 may be spatially distributed into a medium voltage winding region and a low voltage winding region. The medium-voltage windings connected with different medium-voltage ports are arranged in the same medium-voltage winding area, and the medium-voltage windings connected with different medium-voltage ports are arranged in different medium-voltage winding areas, namely the medium-voltage windings connected with each medium-voltage port are independently arranged in the corresponding medium-voltage winding area. And, in order to reduce the volume of the medium voltage multi-port transformer and reduce the weight of the medium voltage multi-port transformer, all the low voltage windings may be disposed in the same low voltage winding area, or the low voltage windings connected to the plurality of low voltage ports may be disposed in the same low voltage winding area. When a low-voltage winding area comprises a low-voltage winding connected with a plurality of low-voltage ports, the low-voltage winding in the low-voltage winding area can adopt an internal and external layered structure, a sandwich structure or a multi-line parallel winding structure according to the related leakage inductance and loss requirements. It should be noted that, insulation requirements under low voltage are satisfied between low voltage windings adjacent to each other and connected with different low voltage ports, between different layers of the same winding, and between different turns of the same layer winding, that is, the low voltage insulation requirements are satisfied, and the implementation manner is in the prior art and is not described herein.

The embodiment of the invention adopts the technical scheme, and the medium-voltage multiport transformer comprises: and the medium-voltage windings connected with the medium-voltage ports in the ports are independently arranged in the corresponding medium-voltage winding areas, so that the medium-voltage windings and other devices meet corresponding insulation requirements. It can be seen that the embodiment of the invention can provide a transformer with medium voltage ports meeting corresponding insulation requirements, and the number of the ports is greater than or equal to 3.

In the embodiment of the invention, solid insulation can be formed in the medium-voltage winding area through a casting process.

In a specific example, fig. 2 is a schematic structural diagram of another medium voltage multi-port transformer according to an embodiment of the present invention. As shown in fig. 2, the medium voltage multi-port transformer includes: a solar core 11, a medium voltage port and two low voltage ports, the medium voltage winding 21 of the medium voltage port and the low voltage windings 22 of the two low voltage ports are wound on the same leg of the core 11.

Fig. 3 is a schematic illustration of insulation casting of a medium voltage winding corresponding to fig. 2, according to an embodiment of the present invention. In fig. 3, fig. (a) is a schematic perspective view of the medium voltage multi-port transformer, and (b) is a top cross-sectional view of the remaining part of the medium voltage multi-port transformer cut by the dicing line 36. As shown in fig. 3, in the medium voltage winding region, the solid insulation 31 is formed by a casting process, and the outer surface of the solid insulation 31 is provided with a shielding layer 33, and the shielding layer 33 is used for shielding the medium voltage winding 21. The low-voltage winding 22 and the magnetic core 11 are arranged externally, interlayer insulation 34 is arranged between the low-voltage windings 22 connected with the same low-voltage port, and inter-winding insulation 35 is arranged between the low-voltage windings 22 connected with different low-voltage ports.

According to the technical scheme, only the medium-voltage winding is insulated and cast, and the low-voltage winding and the magnetic core are arranged externally; because the low-voltage winding and the magnetic core are arranged externally, the heat dissipation of the low-voltage winding and the magnetic core is relatively good, the working temperature range of the transformer is enlarged, and after insulation casting is completed, a user is supported to adjust the number, the structure, the number of turns of any low-voltage winding, the size of the magnetic core and the like at any time, so that the transformer has expandability.

In the embodiment of the invention, the solid insulation has an umbrella skirt structure.

The other outer surfaces of the solid insulation except the outer surface of the umbrella skirt structure are surrounded by corresponding shielding layers.

Specifically, as shown in fig. 3 (a), the solid insulation 31 has umbrella skirt structures 32, and the number of umbrella skirt structures 32 is 1 or more (1 is illustrated in fig. 3 as an example). The umbrella skirt structure is arranged, so that the creepage distance can be increased, and the insulating capability is improved.

As shown in fig. 3 (b), the outer surface of the solid insulation 31 is provided with a shielding layer 33. The arrangement position and structure of the shielding layer 33 will be described in detail with reference to fig. 4.

Fig. 4 is a schematic view of a shielding layer corresponding to fig. 3 according to an embodiment of the present invention. In fig. 4, fig. (c) is a schematic perspective view of a medium voltage multi-port transformer, and (d) is a front view of the medium voltage multi-port transformer. As shown in fig. 4, the winding bore surface 41, the solid insulated side surface 42, and the outside of the solid insulated bottom surface (not shown in fig. 4) are each provided with a shielding layer 33.

Specifically, the shielding layer 33 may be a metal shell structure, in which case the present transformer may be applied to a non-high frequency high magnetic field region, and in addition, the shielding layer 33 may be formed in other manners in the prior art, and embodiments of the present invention are not limited herein.

In the embodiment of the present invention, as shown in fig. 4 (d), the junction between the shielding layer 33 and the umbrella skirt structure 32 may adopt a curved surface structure 43. In this way, electric field distortion can be reduced. The solid insulating side 42 includes a surface of a curved structure 43.

In addition, the grading ring is buried in the joint between the shielding layer 33 and the umbrella skirt structure 32 instead of adopting the curved surface structure 43, so that the electric field distortion can be reduced.

In the embodiment of the invention, the medium-voltage multi-port transformer can adopt a single-winding column structure, a double-winding column structure or a multi-winding column structure.

It should be noted that, the foregoing examples and the following examples of the present invention are both described by taking a single winding column structure as an example, and those skilled in the art will easily think of a specific implementation of other structures according to the embodiments of the present invention, so that the present invention is not repeated here for a medium voltage multi-port transformer adopting a dual winding column structure or a multi winding column structure.

In the embodiment of the invention, when the medium-voltage winding and the low-voltage winding are simultaneously arranged on the same winding column, the medium-voltage winding is wound on the outer side of the low-voltage winding.

As shown in fig. 2, all the medium voltage windings 21 and all the low voltage windings 22 of the transformer are wound on the same pole of the magnetic core 11, the windings are nested one by one, and the medium voltage windings 21 are wound on the outer side of the low voltage windings 22. Therefore, the medium-voltage winding is conveniently insulated and poured, and further, insulation design is convenient.

In the embodiment of the invention, other devices can be further cast according to actual requirements on the basis of the scheme.

Based on this, in the embodiment of the present invention, when the number of the low-voltage windings is greater than or equal to 2, all the medium-voltage windings and part of the low-voltage windings may be placed in the corresponding solid insulation by a casting process.

In a specific example, fig. 5 is a schematic diagram of insulation casting of a medium voltage winding and a portion of a low voltage winding corresponding to fig. 2 according to an embodiment of the present invention. In fig. 5, (e) is a schematic perspective view of the medium voltage multi-port transformer, and (f) is a cross-sectional top view of the rest of the medium voltage multi-port transformer cut by the dicing line 36. As shown in fig. 5, the present solution is similar to the solution shown in fig. 3, except that in this embodiment, all the medium-voltage windings 21 and the low-voltage windings 22 connected to one low-voltage port are placed in the corresponding solid insulation 31 by casting, and the low-voltage windings 22 connected to the other low-voltage port are externally arranged.

Based on this, in the present solution, because part of the low-voltage winding 22 is external, the present solution maintains the expandability of the transformer; and, since the low-voltage winding layer adjacent to the inner side of the medium-voltage winding 21 serves as a shielding layer of the inner side of the medium-voltage winding 21 in the solid insulation 31, as shown in fig. (f), in this scheme, the winding hole surface 41 does not need shielding treatment, so that the shielding treatment difficulty and the shielding material consumption are reduced in this scheme; no additional insulation is required between the low-voltage winding 22 inside the solid insulation 31 and the external low-voltage winding 22; in addition, the scheme supports the externally arranged low-voltage winding 22 with higher working temperature so as to facilitate heat dissipation; further, compared with the scheme shown in fig. 3, the transformer equivalent circuit parameter consistency and shock resistance of the scheme are further improved, wherein the transformer equivalent circuit parameter comprises self inductance, leakage inductance, equivalent turn ratio and the like.

In the embodiment of the invention, all the medium-voltage windings and all the low-voltage windings can be placed in corresponding solid insulation through a casting process.

In a specific example, fig. 6 is a schematic diagram of insulation casting of a medium voltage winding and all low voltage windings corresponding to fig. 2 provided by an embodiment of the present invention. In fig. 6, fig. (g) is a schematic perspective view of the medium voltage multi-port transformer, and (h) is a top cross-sectional view of the remaining part of the medium voltage multi-port transformer cut by the dicing line 36. As shown in fig. 6, the present solution is similar to the solution shown in fig. 5, except that in the present embodiment, all the medium voltage windings 21 and all the low voltage windings 22 are placed in the corresponding solid insulation 31 by a casting process, and no low voltage windings 22 are externally arranged.

In the practical application process, the preparation flow of the transformer is as follows: firstly, all windings are wound, and insulation treatment is carried out among windings connected with different ports, among different layers of windings connected with the same port and among different turns of the same winding layer. Then, insulating casting is performed. Then, an outer shielding treatment, i.e., a shielding layer is provided, is performed. Finally, the winding and the magnetic core are assembled.

In the scheme, the solid insulation 31 can be utilized to realize insulation among windings connected with different ports, between layers of windings connected with the same port and between turns of the same winding layer, so that in the preparation process of the transformer, a user is prevented from conducting insulation treatment among windings connected with different ports, between layers of windings connected with the same port and between turns of the same winding layer; and in the actual assembly process, only the magnetic core is required to be assembled, so that the assembly difficulty of the transformer is reduced; in addition, compared with the scheme shown in fig. 5, the transformer equivalent circuit parameter consistency and the shock resistance of the scheme are further improved.

In the embodiment of the invention, all the medium-voltage windings, all the low-voltage windings and the magnetic core can be placed in corresponding solid insulation through a casting process.

In a specific example, fig. 7 is a schematic diagram of a medium voltage winding, all low voltage windings and core insulation casting corresponding to fig. 2, and is a top cross-sectional view of the remainder of the medium voltage multi-port transformer after cutting with cut line 36, according to an embodiment of the present invention. As shown in fig. 7, the present solution is similar to that shown in fig. 6, except that in the present embodiment, all the medium voltage windings 21, all the low voltage windings 22 and the magnetic core 11 are placed in the corresponding solid insulation 31 by a casting process.

Based on the above, in the scheme, in the actual assembly process, the assembly is not needed, so that the assembly difficulty of the transformer is further reduced; in addition, compared with the scheme shown in fig. 6, the transformer equivalent circuit parameter consistency and the shock resistance of the scheme are further improved.

Since the core 11 is affected by the medium voltage in the medium voltage winding 21 to form a floating potential and thus affect insulation, it is necessary to provide a potential extraction (not shown in fig. 7) for the core 11, specifically, to perform the potential extraction by connecting the core 11 to an external conductive material. And, for the shielding layer 33 in each of the above embodiments, the potential of the shielding layer may be brought to the set potential by means of copper foil or the like.

In the embodiment of the invention, when the number of the medium voltage ports is equal to 1, the wire outlet direction of the medium voltage winding is set differently from the wire outlet direction of the low voltage winding; and when the number of the medium voltage ports is greater than or equal to 2, the wire outlet directions of the medium voltage windings connected with the different medium voltage ports are set differently. Thus, the volume of the transformer is reduced while a sufficient space distance is ensured between the adjacent low-voltage windings and the adjacent medium-voltage windings and between the adjacent medium-voltage windings.

In a specific example, as shown in fig. 2, the outgoing direction of the medium voltage port outgoing line 23 is perpendicular to the outgoing direction of the low voltage port outgoing line 24.

It should be noted that, the wire outlet direction of the winding may also be other manners, for example, in fig. 2, the wire outlet direction of the medium voltage port wire outlet 23 may be parallel to the plane of the magnetic core 11 and perpendicular to the wire outlet direction of the low voltage port wire outlet 24. The present invention is not particularly limited as long as it can be advantageous to reduce the volume of the transformer while ensuring a sufficient space distance between adjacent low-voltage windings and medium-voltage windings and between adjacent medium-voltage windings.

In the embodiment of the invention, the number of windings connected with any one port is greater than or equal to 1; when the number of windings connected with the port is larger than 1, the windings connected with the port are connected in series-parallel.

Specifically, the series-parallel connection between windings specifically means that the windings are connected in at least one of series connection and parallel connection. In a specific example, fig. 8 is a schematic structural diagram of another medium voltage multi-port transformer according to an embodiment of the present invention. As shown in fig. 8, 3 windings connected to the port on the left side of the core 11 are connected in parallel, and two windings connected to the port on the right side of the core 11 are connected in series.

In addition, the multiple ports of the transformer can be equivalent to one port through synchronous control of an external power electronic converter, and particularly, the multiple windings are externally connected with the synchronous control power electronic converter, and the transformer can be regarded as one port to the outside even if the voltage and current characteristics are completely consistent, and the transformer is not directly connected in series and parallel. In this way, better energy scheduling is achieved.

Based on a general inventive concept, the invention also provides a medium voltage multi-port ac coupling converter. Fig. 9 is a schematic structural diagram of a medium voltage multi-port ac-coupled converter according to an embodiment of the present invention. As shown in fig. 9, the present medium voltage multi-port ac coupling converter includes: n medium voltage multiport transformers 91 as described above, and n×m conversion circuits 92; n is greater than or equal to 1; m is the number of ports of the medium voltage multi-port transformer 91.

Wherein each port of the medium voltage multi-port transformer 91 is connected to a corresponding power source or load, respectively, through a corresponding conversion circuit 92.

Specifically, a medium voltage multiport transformer 91 and its connected conversion circuits 92 are located in the same module. Each port of the medium voltage multi-port transformer 91 is connected to the ac side of the corresponding conversion circuit 92, and as an ac coupling link, energy scheduling between different ports can be achieved, that is, each port can be arbitrarily configured as an energy input or output port, but cannot be an input or output port at the same time.

In the embodiment of the invention, as shown in fig. 9, a cascade H bridge is adopted at the medium voltage side of the medium voltage multi-port ac coupling converter, specifically, each medium voltage port of the medium voltage multi-port transformer 91 is respectively cascaded through a corresponding conversion circuit, so as to realize the grid connection of a single-phase medium voltage grid; and each low-voltage port of the medium-voltage multi-port transformer is independently output through a corresponding conversion circuit.

In the embodiment of the invention, the module is connected to an external medium-voltage port of the medium-voltage multiport transformer 91 through a two-stage power electronic converter; the module is connected to the external low voltage port through a primary power electronic converter to the low voltage port of the medium voltage multiport transformer 91. Specifically, as shown in fig. 9, the conversion circuit to which the medium voltage port of the medium voltage multi-port transformer 91 is connected includes: the AC/DC conversion circuit and the DC/AC conversion circuit are connected on the direct current sides; the conversion circuit to which the low-voltage port of the medium-voltage multiport transformer 91 is connected includes: an AC/DC conversion circuit.

For the foregoing method embodiments, for simplicity of explanation, the methodologies are shown as a series of acts, but one of ordinary skill in the art will appreciate that the present invention is not limited by the order of acts, as some steps may, in accordance with the present invention, occur in other orders or concurrently. Further, those skilled in the art will also appreciate that the embodiments described in the specification are all preferred embodiments, and that the acts and modules referred to are not necessarily required for the present invention.

It should be noted that, in the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described as different from other embodiments, and identical and similar parts between the embodiments are all enough to be referred to each other.

Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (15)

1. A medium voltage multi-port transformer, comprising: a magnetic core, a plurality of windings and m ports; m is greater than or equal to 3;

the m ports include: at least one medium pressure port and at least one low pressure port;

each winding is wound on the magnetic core respectively;

each winding is respectively as follows: a medium voltage winding connected to the medium voltage port, and a low voltage winding connected to the low voltage port;

the medium-voltage windings are independently arranged in the corresponding medium-voltage winding areas so as to meet corresponding insulation requirements with other devices.

2. The medium voltage multiport transformer of claim 1, wherein solid insulation is formed by a casting process in the medium voltage winding region.

3. The medium voltage multiport transformer of claim 2, wherein the solid insulation has an umbrella skirt structure;

the other outer surfaces of the solid insulation except the outer surface of the umbrella skirt structure are surrounded by corresponding shielding layers.

4. A medium voltage multiport transformer according to claim 3, wherein the junction of the shielding layer and the shed structure adopts a curved surface structure.

5. The medium voltage multiport transformer of claim 1, wherein the medium voltage multiport transformer adopts a single winding limb structure, a double winding limb structure, or a multiple winding limb structure.

6. The medium voltage multiport transformer according to claim 1, wherein when the medium voltage winding and the low voltage winding are simultaneously provided on the same winding post, the medium voltage winding is wound on an outer side of the low voltage winding.

7. The medium voltage multiport transformer according to any of claims 1 to 6, wherein when the number of low voltage windings is greater than or equal to 2, all the medium voltage windings and part of the low voltage windings are placed in the corresponding solid insulation by a casting process.

8. Medium voltage multiport transformer according to any of claims 1 to 6, wherein all the medium voltage windings and all the low voltage windings are placed in the corresponding solid insulation by a casting process.

9. The medium voltage multiport transformer according to any of claims 1 to 6, wherein all of said medium voltage windings, all of said low voltage windings, and said magnetic core are placed in corresponding solid insulation by a casting process.

10. The medium voltage multiport transformer according to any one of claims 1 to 6, wherein when the number of the medium voltage ports is equal to 1, the wire outlet direction of the medium voltage winding is set differently from the wire outlet direction of the low voltage winding.

11. The medium voltage multiport transformer according to any one of claims 1 to 6, wherein when the number of the medium voltage ports is 2 or more, the wire outlet direction of the medium voltage winding to which the medium voltage ports are connected is set differently.

12. The medium voltage multiport transformer according to any of claims 1 to 6, wherein the number of windings to which any one of said ports is connected is greater than or equal to 1;

when the number of windings connected with the port is larger than 1, the windings connected with the port are connected in series-parallel.

13. A medium voltage multi-port ac coupled converter comprising: n medium voltage multiport transformers according to any of claims 1 to 11, and n x m conversion circuits; n is greater than or equal to 1; the m is the port number of the medium-voltage multi-port transformer;

each port of the medium voltage multi-port transformer is connected to a corresponding power supply or load through a corresponding conversion circuit.

14. The medium voltage multi-port ac coupling converter according to claim 13, wherein each low voltage port of the medium voltage multi-port transformer is independently output through a corresponding one of the conversion circuits, and each medium voltage port of the medium voltage multi-port transformer is cascaded through a corresponding one of the conversion circuits.

15. The medium voltage multi-port ac coupling converter according to claim 13, wherein the conversion circuit to which the medium voltage port of the medium voltage multi-port transformer is connected comprises: the AC/DC conversion circuit and the DC/AC conversion circuit are connected on the direct current sides;

the conversion circuit to which the low-voltage port of the medium-voltage multiport transformer is connected includes: an AC/DC conversion circuit.