CN113690027A

CN113690027A - High-frequency high-power water-cooled transformer suitable for power electronic transformer

Info

Publication number: CN113690027A
Application number: CN202110961899.3A
Authority: CN
Inventors: 范建华; 徐鹏飞; 王庆园; 于晓强; 韩长忠; 谢堂林
Original assignee: Qingdao Topscomm Communication Co Ltd
Current assignee: Qingdao Topscomm Communication Co Ltd
Priority date: 2021-08-20
Filing date: 2021-08-20
Publication date: 2021-11-23

Abstract

The invention relates to the technical field of power systems, and particularly discloses a high-frequency high-power water-cooled transformer suitable for a power electronic transformer, which comprises a primary winding (1), a secondary winding (2), an iron core (3), an insulating material (4) and a connecting and supporting structure (5). The transformer has the advantages that the requirement of a high-frequency high-power supply on the transformer can be met, the loss is small, the temperature rise is low, the reliability is high, and the like.

Description

High-frequency high-power water-cooled transformer suitable for power electronic transformer

Technical Field

The invention relates to the technical field of power systems, in particular to a high-frequency high-power water-cooled transformer suitable for a power electronic transformer.

Background

The traditional power frequency transformer has the defects of high energy consumption, easy waveform distortion, low fault response speed and the like, and can not meet the requirement of building a strong smart grid. The power electronic transformer overcomes the defects of the power frequency transformer, has the advantages of multi-port output, bidirectional energy flow and the like, and is paid more and more attention. The high-frequency transformer is a main device of the power electronic transformer, but is limited by the problems of loss, heat dissipation and the like of winding materials under high frequency, and the power of the high-frequency transformer is difficult to be increased.

The main winding materials of the high-frequency transformer at present are as follows: litz wire, copper tubing, or copper foil.

For a high-power high-frequency transformer, in order to ensure proper current-carrying capacity, litz wires with a large number of strands are required to be used, the positions of enameled wires are inconsistent during twisting, the outer diameter is large, the heat dissipation conditions of the inside and the outside of a wire are different, the internal temperature rise is obviously higher than the outside, the internal enameled wires are easy to overheat, a paint film is damaged, adhesion is generated between the enameled wires, and the significance of reducing high-frequency resistance by the litz wires is lost.

The mode of using the copper pipe to make the winding, when the wall thickness of the copper pipe is greater than the skin depth, the current flows only on the surface of the copper pipe, a very thick copper pipe needs to be used in order to ensure enough current-carrying capacity, and meanwhile, the copper pipe has high hardness and is not easy to use, and the pipeline can be damaged irreversibly if the copper pipe is bent at a large angle in the manufacturing process. If copper foils are used as windings and stacked, the proximity effect is obvious under high frequency, so that loss is increased, insulating paper needs to be added between every two layers of copper foils for insulation, heat dissipation is poor, and temperature rise is too high.

The litz wire (6) with the cooling water channel in the patent, the cooling water channel (7) adopts 1-3 layers of seamless soft insulating materials, and then the litz wire (8) with the diameter of a plurality of strands of single wires being 0.05-0.5 mm is formed by complex twisting by taking the litz wire as a circle center. The cooling water channel is made of soft materials, the wire is made of thin enameled copper wires, and a finished product has good flexibility and is easy to use. The single-stranded wires are guaranteed to be in symmetrical positions by twisting around the cooling water channels, high-frequency loss is reduced beneficially, and meanwhile heat dissipation is facilitated. The transformer made of the wire has the advantages of small loss, low temperature rise, high reliability and the like.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides the high-frequency high-power water-cooled transformer suitable for the power electronic transformer, and the loss and the temperature rise of the transformer are reduced by adopting the litz wire with the cooling water channel as the transformer winding, so that the transformer with the advantages of small loss, low temperature rise, high reliability and the like is manufactured.

The purpose of the invention can be realized by the following technical scheme, and the high-frequency high-power water-cooled transformer suitable for the power electronic transformer comprises a primary winding, a secondary winding, an iron core, an insulating material, a connecting and supporting structure, wherein:

the primary winding is connected with an energy input end in the circuit and receives input voltage and current;

the secondary winding is connected with an energy output end in the circuit and outputs voltage and current;

at least one position of the primary winding (1) and the secondary winding (2) is wound by a litz wire (6) with a cooling water channel; when the primary winding (1) or the secondary winding (2) does not adopt the litz wire (6) with the cooling water channel, the litz wire (6) without the cooling water channel, copper foil or aluminum foil can be selected for winding according to the use environment;

the transformer comprises an iron core and a transformer magnetic flux main path, wherein the iron core is used for coupling a primary winding and a secondary winding of the transformer to realize power transmission and uses a ferrite magnetic core or a nanocrystalline magnetic core;

the insulating material comprises a material used for insulating and coating the primary winding and the secondary winding of the transformer;

the connecting and supporting structure is used for connecting the copper terminal and the litz wire subjected to paint removal treatment in a crimping and welding mode to serve as an outlet terminal of the transformer; the matched water channel head is connected with the inlet and the outlet of the cooling water channel to form a water inlet and outlet channel opening.

The water channel of the litz wire with the cooling water channel adopts 1-3 layers of seamless soft insulating materials as the circle center, and is formed by multiple twisting of a plurality of strands of enameled wires with the single wire diameter of 0.05-0.5 mm.

Furthermore, the cooling water channel is made of Teflon or silicon rubber, and the wall of the cooling water channel can be thickened or a plurality of layers of pipes are used for ensuring the tightness of the cooling water channel.

Furthermore, a certain number of enameled wires are stranded into stranded wires in a free stranding mode, then 3-7 strands of stranded wires are stranded again to form composite stranded wires, and finally the composite stranded wires are stranded by taking the cooling water channel as the center of a circle to form the litz wire with the cooling water channel.

Furthermore, the litz wire with the cooling water channel and the insulating material are wound into a coil to be used as a winding of the transformer, and the winding, the iron core and the insulating material of the transformer are combined into the high-frequency high-power transformer through a connecting and supporting structure.

The invention has the beneficial technical effects that: the litz wire with the cooling water channel is used as the winding of the transformer, so that the position symmetry of each enameled wire is good, the alternating current resistance of the transformer is reduced, the high-frequency loss of the transformer is reduced, meanwhile, the cooling water channel is arranged in the winding, the heat in the winding can be taken away, the temperature rise in the winding is reduced, the reliability of the transformer is improved, the extra loss caused by the resistance increase due to the temperature rise of the winding is reduced, and the loss of the transformer is further reduced. The transformer has the advantages of small loss, low temperature rise, high reliability and the like.

Drawings

Fig. 1 is a schematic structural diagram of a high-frequency high-power water-cooled transformer suitable for a power electronic transformer.

Fig. 2 is a schematic structural diagram of a litz wire with a cooling water channel of a high-frequency high-power water-cooled transformer applicable to a power electronic transformer.

Fig. 3 is a schematic diagram of a high-frequency high-power water-cooled transformer using litz wires with cooling water channels at the secondary side.

Reference numerals: the winding comprises a primary winding 1, a secondary winding 2, an iron core 3, an insulating material 4, a connecting and supporting structure 5, a litz wire with a cooling water channel 6, a cooling water channel 7, a single-core enameled wire 8, a stranded wire formed by twisting a plurality of strands of enameled wires 9 and a compound stranded wire formed by compound twisting of the stranded wire 10.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

As shown in fig. 1, a high-frequency high-power water-cooled transformer suitable for power electronic transformers comprises 1 a primary winding, 2 a secondary winding, 3 an iron core, 4 an insulating material, 5 a connecting and supporting structure, 6 litz wires with cooling water channels, and 7 cooling water channels. The litz wire 6 with the cooling water channel is used for both the primary winding 1 and the secondary winding 2 of the transformer, and specifically, the litz wire 6 with the cooling water channel is wound on a cylinder framework with the diameter of 70mm and is wound for 20 circles to be used as the secondary winding 2 of the transformer. The litz wire 6 with the cooling water channel is wound on a cylinder framework with the diameter of 140mm and is wound for 20 circles to be used as a primary winding 1 of the transformer. Separating the water channel 7 from the enameled copper wire at the wire outlet positions of the primary winding 1 and the secondary winding 2, performing paint removal operation on the enameled copper wire, and connecting the copper wire with a copper terminal through crimping and welding operation to be used as a wire outlet terminal of the transformer; the matched water channel head is connected with the water channel of the cooling water channel to form a water inlet and outlet channel opening. A coil structure with high protection, strong insulation and easy fixation is formed by encapsulating the primary winding with epoxy resin. The winding, the iron core 3 and the insulating material 4 of the transformer are combined into the high-frequency high-power transformer through the transformer base, the side clamping plate and other connecting and supporting structures 5.

The primary and secondary of the high-frequency transformer adopt litz wires with cooling water channels, and the litz wires are connected with cooling water through the matched water channel interfaces, so that the cooling water can take away the heat of the litz wires during working, the temperature of a winding is reduced, and the reliability of the transformer is greatly improved.

Similarly, if the primary winding and the secondary winding need to be insulated at high voltage, the cooling water may become a conductive path, which results in the insulation failure of the primary winding and the secondary winding, and one of the windings may be replaced by litz wire without water channel, copper foil or aluminum foil according to the magnitude of the winding current and the working frequency in order to ensure the high reliability of the electrical insulation. As shown in fig. 3, the litz wire with cooling water channels is used at the secondary side, and the high-frequency high-power water-cooled transformer without the litz wire with the cooling water channels is used at the primary side. Specifically, the litz wire 6 with the cooling water channel is wound on a cylinder framework with the diameter of 70mm and is wound for 20 circles to be used as a secondary winding 2 of the transformer. The litz wire 11 without the cooling water channel was wound on a cylindrical bobbin with a diameter of 140mm for 20 turns as the primary winding 1 of the transformer. The primary winding 1 carries out paint removal operation on the enameled copper wire at the wire outlet position, and the copper wire is connected with a copper terminal through crimping and welding operation to be used as a primary wire outlet terminal of the transformer; separating the water channel 7 from the enameled copper wire at the wire outlet position of the secondary winding 2, performing paint removal operation on the enameled copper wire, and connecting the copper wire with a copper terminal through crimping and welding operation to be used as a secondary wire outlet terminal of the transformer; the matched water channel head is connected with the water channel of the cooling water channel to form a water inlet and outlet channel opening. A coil structure with high protection, strong insulation and easy fixation is formed by encapsulating the primary winding with epoxy resin. The winding, the iron core 3 and the insulating material 4 of the transformer are combined into the high-frequency high-power transformer through the transformer base, the side clamping plate and other connecting and supporting structures 5.

As shown in fig. 2, a litz wire with a cooling water channel, wherein 8 is a single core enameled wire, an enameled wire with a copper wire diameter of 0.1mm is used, 9 is a twisted wire formed by twisting a plurality of enameled wires, 100 strands of enameled wires with a diameter of 0.1mm are used for twisting, 10 is a composite twisted wire formed by twisting 5 strands of twisted wires, and 6 is a litz wire with a cooling water channel, wherein 9 strands of composite twisted wires are wound around a cooling water channel 7 as a center of a circle, and a teflon hose with an outer diameter of 6.5mm and an inner diameter of 4.5mm is used for the cooling water channel.

In the above embodiments, the high-frequency high-power water-cooled transformer of the present invention is applied to the field of power electronic transformers, and as other embodiments, may also be applied to the fields of ac/dc power distribution networks, power electronic technologies, and power systems.

In the above embodiments, the high-power water-cooled transformer of the present invention is applied to a high-frequency transformer, and as another embodiment, it may be applied to a low-frequency transformer and a medium-frequency transformer.

The above-mentioned embodiments are illustrative of the specific embodiments of the present invention, and are not restrictive, and those skilled in the relevant art can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention, so that all equivalent technical solutions should be included in the scope of the present invention.

Claims

1. The utility model provides a high-frequency high-power water-cooled transformer suitable for power electronic transformer, contains primary winding (1), secondary (2), iron core (3), insulating material (4), connection and bearing structure (5), its characterized in that:

at least one position of the primary winding (1) and the secondary winding (2) is wound by a litz wire (6) with a cooling water channel.

2. The high-frequency high-power water-cooled transformer applicable to the power electronic transformer is characterized in that when the litz wire (6) with the cooling water channel is not adopted in the primary winding (1) or the secondary winding (2), the litz wire (6), the copper foil and the aluminum foil without the cooling water channel can be selected and wound according to the use environment.

3. The high-frequency high-power water-cooled transformer applicable to the power electronic transformer is characterized in that the cooling water channel (7) is made of 1-3 layers of seamless soft insulating materials.

4. The high-frequency high-power water-cooled transformer applicable to the power electronic transformer is characterized in that the litz wire is formed by twisting a plurality of enameled wires (8) with the diameter of a single wire of 0.05-0.5 mm by taking a cooling water channel as a center.