Photovoltaic grid-connected low-loss step-up transformer with magnetic shielding structure

Abstract

The application relates to the technical field of photovoltaic transformers, and discloses a photovoltaic grid-connected low-loss step-up transformer integrated with a magnetic shielding structure, which comprises a transformer shell and a transformer winding arranged in the inner cavity of the transformer shell, and the side surface of the transformer winding is provided with a side surface outer shielding plate; and the side surface outer shielding plate is provided with a self-adapting heat dissipation structure. In the application, the self-adapting heat dissipation structure integrated on the side surface outer shielding plate cooperates with the cooling space arranged on the outer side of the transformer shell, so that the heat generated by the leakage magnetic eddy current and the transformer winding can be accurately and efficiently taken away by the heat-conducting medium which is forced to circulate at the position closest to the heat source, heat exchange of the heat in the core area is realized, the hotspot temperature of the transformer winding is greatly reduced, the heat dissipation efficiency and the overload capacity of the transformer are improved, perfect dynamic matching of the heat dissipation capacity and the actual load is realized, the safety of the transformer is ensured, and energy saving and consumption reduction are maximized.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of photovoltaic transformers, in particular to a photovoltaic grid-connected low-loss step-up transformer integrated with a magnetic shielding structure. BACKGROUND

[0002] As a core device in the power system, the stable operation of the power transformer is crucial. For a large-capacity transformer, the huge leakage magnetic field generated by the winding can cause local overheating of the metal structural parts such as the oil tank, thereby increasing the loss. Therefore, by setting a magnetic shielding structure composed of high magnetic permeability materials (such as silicon steel sheets) or high electrical conductivity materials (such as copper plates) outside the winding, the leakage of the magnetic field is suppressed, which is a mature technology to ensure the safe operation of the transformer. In the photovoltaic grid-connected system, the step-up transformer undertakes the key task of raising the low voltage output by the photovoltaic array to the grid voltage level, which is a necessary link to realize energy grid connection. The intermittent and fluctuating nature of photovoltaic power generation requires the grid-connected transformer to frequently withstand the load fluctuations caused by the transients of solar radiation intensity, which puts forward more stringent requirements on the leakage magnetic field suppression and heat dissipation capacity of the transformer than traditional transformers.

[0003] However, the existing technology has certain deficiencies in dealing with the particularity of the photovoltaic grid-connected scene. First, the traditional magnetic shielding structure is usually a static shielding member, and its design and heat dissipation system are independent of each other. The heat generated by the eddy current loss on the shielding body becomes waste heat that needs to be passively dissipated, increasing the heat dissipation burden of the core area and being unable to cope with the dynamic thermal shock caused by load fluctuations. Second, the existing forced circulation cooling method, such as using an external oil pump to extract transformer oil for cooling and then recycling, is effective, but its operation mode is relatively extensive. In the face of the instability of the normal load of photovoltaic power generation, this cooling system often needs to run at a high power for a long time to ensure safety at peak times, resulting in a huge pumping energy consumption during most of the medium and low load periods, reducing the overall economic benefit and energy utilization efficiency of the photovoltaic power station, and failing to achieve fine and intelligent management of the heat dissipation resources. SUMMARY

[0004] The technical problem to be solved by the present application is that the existing technology cannot adapt to the fluctuations of photovoltaic load due to the use of static magnetic shielding and extensive forced cooling, resulting in heavy heat dissipation burden and high energy consumption. Therefore, we propose a photovoltaic grid-connected low-loss step-up transformer integrated with a magnetic shielding structure.

[0005] To achieve the above purpose, the following technical solution is adopted: a photovoltaic grid-connected low-loss step-up transformer integrated with a magnetic shielding structure, comprising a transformer shell and a transformer winding arranged in the inner cavity of the transformer shell, and a side outer shielding plate arranged on the side surface of the transformer winding.

[0006] The adaptive heat dissipation structure is arranged on the side outer shielding plate and comprises a channel arranged on the inner side of the side outer shielding plate and used for passing the heat conducting medium, the upper end and the lower end of the side outer shielding plate are respectively provided with an interface in communication with the channel, the inner side of the side outer shielding plate is provided with a storage cavity, the storage cavity is provided with a phase change material in the cavity, the bottom end of the storage cavity is provided with a movable cavity, the bottom end of the storage cavity is provided with a telescopic part corresponding to the movable cavity, and one end of the movable cavity is provided with a driving assembly in linkage with the telescopic part and used for adjusting the inner diameter or the length of the channel.

[0007] The side of the transformer shell is provided with a cooling space for cooling the heat conducting medium, the outer side of the transformer shell is provided with an oil pump corresponding to the cooling space, the interface at the upper end of the side outer shielding plate is in communication with the cooling space through a first pipeline, the interface at the lower end of the side outer shielding plate is connected with the output end of the oil pump through a second pipeline, and the input end of the oil pump is in communication with the cooling space, so that the circulation of the heat conducting medium can be realized.

[0008] Preferably, the cooling space comprises a cooling box arranged on the side of the transformer shell, the upper end of the inner side of the cooling box is provided with an oil storage tank for storing the heat conducting medium, the bottom of the oil storage tank is in communication with a cooling pipe, the lower end of the cooling pipe is connected with the input end of the oil pump, and the cooling box is provided with a heat dissipation fan.

[0009] Preferably, the channel for passing the heat conducting medium comprises a heat dissipation flow channel arranged on the inner side of the side outer shielding plate, and the upper end and the lower end of the heat dissipation flow channel are in communication with the two interfaces respectively.

[0010] Preferably, the channel for passing the heat conducting medium comprises a main heat dissipation flow channel and a sub heat dissipation flow channel arranged on the inner side of the side outer shielding plate, and the upper end and the lower end of the main heat dissipation flow channel and the sub heat dissipation flow channel are in communication with the two interfaces respectively.

[0011] Preferably, the driving assembly comprises a rack arranged at one end of the telescopic part, a sealing ball movably and sealingly arranged on the inner side of the heat dissipation flow channel, a first through hole arranged on the sealing ball, and a gear meshing with the rack arranged at one end of the sealing ball.

[0012] Preferably, the driving assembly comprises a traction rod movably arranged at one end of the telescopic part, a sealing plate movably and sealingly arranged on the inner side of one end of the heat dissipation flow channel, a second through hole arranged on the sealing plate, and one end of the traction rod movably connected with one end of the sealing plate.

[0013] Preferably, the driving assembly comprises a sealing ball movably and sealingly arranged in the main heat dissipation flow channel or the sub heat dissipation flow channel, a first through hole arranged on the sealing ball, a rack arranged at one end of the telescopic part, and a gear meshing with the rack arranged at one end of the sealing ball.

[0014] Preferably, the driving assembly comprises a sealing plate movably arranged in the main heat dissipation flow channel or the auxiliary heat dissipation flow channel, the sealing plate is provided with a second through hole, one end of the telescopic member is movably provided with a traction rod, and the end of the traction rod away from the telescopic member is movably connected with one end of the sealing plate.

[0015] Preferably, the inner side of the movable cavity is provided with an elastic member for resetting the telescopic member.

[0016] Preferably, the phase change material in the storage cavity is paraffin.

[0017] The technical effects and advantages of the present application are as follows:

[0018] In the present application, the self-adaptive heat dissipation structure integrated on the side outer shielding plate cooperates with the cooling space arranged outside the transformer shell, so that the heat generated by the leakage magnetic eddy current and the transformer winding can be accurately and efficiently taken away by the heat-conducting medium forced to circulate at the position closest to the heat source, heat exchange of the core area heat is realized, the transformer winding hotspot temperature is greatly reduced, the heat dissipation efficiency and overload capacity of the transformer are improved, at the same time, the waste heat generated by the side outer shielding plate as a heat dissipation element is actively utilized, the overall structure of the transformer is more compact, the functions are highly integrated and coordinated, and under normal load, it can be automatically switched to the energy-saving circulation mode, which significantly reduces the daily operation energy consumption of the oil pump, and when the load instantaneously rises and the temperature sharply rises due to factors such as cloud cover, the mechanical force generated by the phase change material can automatically switch to the full-flow, high-strength targeted heat dissipation mode, without external sensors and controllers for pure physical self-adaptive adjustment, which not only greatly improves the reliability of the system, but also realizes perfect dynamic matching of the heat dissipation capacity and the actual load, while ensuring the safety of the transformer, the energy saving and consumption reduction are maximized. BRIEF DESCRIPTION OF DRAWINGS

[0019] The disclosed content of the present application will be described with reference to the accompanying drawings. It should be understood that the drawings are only for illustrative purposes, and are not intended to limit the scope of protection of the present application. In the drawings, the same reference signs are used to refer to the same parts:

[0020] Figure 1 is a structural schematic diagram of the present application;

[0021] Figure 2 is a structural schematic diagram of the present application in a disassembled state;

[0022] Figure 3 is a structural schematic diagram of the cooling box of the present application in a disassembled state;

[0023] Figure 4 is a structural schematic diagram of the transformer winding and the side outer shielding plate and the end outer shielding plate of the present application;

[0024] Figure 5 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application;

[0025] Figure 6 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application; Figure 5 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application;

[0026] Figure 7 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application;

[0027] Figure 8 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application;

[0028] Figure 9 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application;

[0029] Figure 10 It is a structural schematic diagram of the side outer shielding plate, the end outer shielding plate in the disassembled state of the application.

[0030] Legend: 1, transformer shell; 2, cooling box; 3, cooling fan; 4, cooling fin; 5, oil pump; 6, side outer shielding plate; 7, end outer shielding plate; 8, oil storage tank; 9, heat dissipation plate; 10, mounting groove; 11, cooling pipe; 12, cutout; 13, collection top pipe; 14, discharge port; 15, collection bottom pipe; 16, inlet; 17, transformer winding; 18, side inner shielding plate; 19, end inner shielding plate; 20, storage cavity; 21, heat dissipation channel; 22, sealing ball; 23, first through hole; 24, telescopic part; 25, elastic part; 26, rack; 27, gear; 28, movable cavity; 29, sealing plate; 30, second through hole; 31, traction rod; 32, main heat dissipation channel; 33, interface; 34, auxiliary heat dissipation channel. DETAILED DESCRIPTION

[0031] It is easy to understand that, according to the technical scheme of the application, a person skilled in the art can propose a plurality of structure modes and implementation modes which can be replaced with each other without changing the essential spirit of the application. Therefore, the following detailed description and the drawings are only exemplary description of the technical scheme of the application, and should not be regarded as the whole or as the limitation or restriction of the technical scheme of the application.

[0032] Reference Figures 1-10As shown, the present application provides a technical solution: a photovoltaic grid-connected low-loss step-up transformer with magnetic shielding structure, comprising a transformer shell 1 and a transformer winding 17 arranged in the inner cavity of the transformer shell 1, the side of the transformer winding 17 is provided with a side outer shielding plate 6, the side outer shielding plate 6 is arranged around the transformer winding 17, and the side outer shielding plate 6 is spliced by a plurality of high-conductivity oxygen-free copper or high-purity aluminum alloy plates, vertical insulation gaps are left between each plate, and epoxy plates or insulation paper plates are filled to cut off the macroscopic eddy current loop, a side inner shielding plate 18 is arranged between the side outer shielding plate 6 and the transformer winding 17, the side inner shielding plate 18 is also arranged around the transformer winding 17, and gaps exist between the side inner shielding plate 18, the side outer shielding plate 6 and the transformer winding 17, the side inner shielding plate 18 adopts high-saturation magnetic induction strength grain-oriented silicon steel sheet similar to the material of the core of the transformer winding 17, and is preferably 30Q130 or higher grade, vertical insulation gaps are also left between each plate, and epoxy plates or insulation paper plates are filled to cut off the macroscopic eddy current loop, end inner shielding plates 19 are arranged at the upper and lower ends of the transformer winding 17, the end inner shielding plates 19 are made of the same material as the side inner shielding plate 18, an end outer shielding plate 7 is arranged on the side of the end inner shielding plate 19 away from the transformer winding 17, the end outer shielding plate 7 is made of the same material as the side outer shielding plate 6, the end outer shielding plate 7 and the end inner shielding plate 19 are both annular plane cover plates with a central hole and at least one radial notch, the central hole is used for leading out the lead, and the radial notch is also used for blocking the annular current, the end inner shielding plate 19, the side inner shielding plate 18 and the transformer winding 17 are separated by insulation struts, the gap simultaneously serves as a main cooling oil channel, and the end inner shielding plate 19, the end outer shielding plate 7, the side inner shielding plate 18 and the side outer shielding plate 6 are all fixed on the iron yoke clamps at the upper and lower ends of the transformer winding 17 by non-magnetic stainless steel or high-strength engineering plastic fasteners, so as to ensure the stability of the structure, the gap between the end outer shielding plate 7 and the end inner shielding plate 19 and the gap between the side inner shielding plate 18 and the side outer shielding plate 6 are also separated by insulation struts to form an oil channel.

[0033] In use, the silicon steel shunt screens of the side inner shielding plate 18 and the end inner shielding plates 19 at the upper and lower ends guide most of the leakage magnetic flux back to the main core, thereby reducing the leakage from the source, and the residual leakage magnetic flux passing through the side inner shielding plate 18 and the end inner shielding plates 19 induces strong eddy currents on the copper plates of the side outer shielding plate 6 and the end outer shielding plate 7, and the generated reverse magnetic field further offsets the leakage magnetic field, thereby achieving high-efficiency shielding.

[0034] In order to adaptively adjust the heat dissipation effect, the adaptive heat dissipation structure is arranged on the side outer shielding plate 6, as a preferred embodiment, the adaptive heat dissipation structure includes a channel arranged on the inner side of the side outer shielding plate 6 and used for passing through the heat conduction medium, the heat conduction medium is preferably the same transformer oil as the inside of the transformer shell 1, the upper and lower ends of the side outer shielding plate 6 are respectively provided with an interface 33 in communication with the channel, the inner side of the side outer shielding plate 6 is provided with a storage cavity 20, the storage cavity 20 is provided with a phase change material in the cavity, the phase change material is preferably industrial paraffin, and the melting point of the paraffin is selected to be about 85°C, when the photovoltaic power station is normal and stable, the transformer temperature rises stably, and the core area temperature is lower than 85°C, so the paraffin remains solid, when the load increases sharply, the transformer loss rises sharply in a short time, the temperature of the transformer winding 17 and the side outer shielding plate 6 will break through 85°C, and then the paraffin melts and absorbs heat, the bottom end of the storage cavity 20 is provided with a movable cavity 28, the bottom end of the storage cavity 20 is provided with a telescopic piece 24 corresponding to the movable cavity 28, the telescopic piece 24 is preferably a metal bellows, and the bottom of the metal bellows is closed, or other telescopic structures can also be replaced, to ensure that the paraffin can push the telescopic when it melts, one end of the movable cavity 28 is provided with a driving assembly linked with the telescopic piece 24 and used for adjusting the inner diameter or length of the channel, which can ensure that the heat conduction medium passes through the channel at a low flow rate in a normal and stable state, and can increase the flow rate of the channel when the load increases greatly, in order to facilitate the reset of the telescopic piece 24, an elastic piece 25 for resetting the telescopic piece 24 is arranged on the inner side of the movable cavity 28, the elastic piece 25 is preferably a spring, and the spring is made of a material affected by temperature, and can ensure that the telescopic piece 24 can be reset when the paraffin solidifies.

[0035] It should be noted that the paraffin is an excellent electrical insulator and a chemically inert substance, which is perfectly compatible with the transformer oil and internal components, the material has the unique physical property of absorbing or releasing a large amount of latent heat in the solid-liquid phase change process while keeping its temperature unchanged, it is safely packaged in the independent storage cavity 20 in the side outer shielding plate 6, it will not participate in conduction, nor will it interfere with the electromagnetic shielding function of the side outer shielding plate 6 in any way to generate eddy current to offset the magnetic flux leakage, which ensures the absolute safety of the electrical performance of the transformer, more importantly, it not only changes its form according to the temperature, but also is a heat buffer, which can absorb a large amount of peak heat in an instant of load impact, effectively suppresses the rapid rise of the hot spot temperature of the transformer winding 17, provides valuable dynamic thermal margin for the transformer, greatly enhances the reliability and safety of the equipment in response to the extreme volatility of photovoltaic power generation.

[0036] Further, in order to realize the circulating flow of the heat conducting medium through the channel, a cooling space for cooling the heat conducting medium is arranged on the side of the transformer housing 1, an oil pump 5 corresponding to the cooling space is arranged on the outside of the transformer housing 1, the interface 33 at the upper end of the side outer shielding plate 6 is connected with the cooling space through a first pipeline, the interface 33 at the lower end of the side outer shielding plate 6 is connected with the output end of the oil pump 5 through a second pipeline, and the input end of the oil pump 5 is connected with the cooling space, so that the circulating flow of the heat conducting medium can be realized, wherein the cooling space comprises a cooling box 2 arranged on the side of the transformer housing 1, an oil storage tank 8 arranged on the inside of the upper end of the cooling box 2 for storing the heat conducting medium, a cooling pipe 11 arranged on the bottom of the oil storage tank 8 in communication, the cooling pipe 11 is in the shape of "S", the lower end of the cooling pipe 11 is connected with the input end of the oil pump 5, a cooling fan 3 is arranged on the cooling box 2 for cooling the inside of the cooling box 2, the first pipeline comprises a collection top pipe 13 arranged on the upper end of the side outer shielding plate 6 and connected with the interface 33 at the upper end of the side outer shielding plate 6, a discharge port 14 is arranged on the collection top pipe 13 and extends to the outside of the transformer housing 1 and is connected with the oil storage tank 8, the second pipeline comprises a collection bottom pipe 15 arranged on the lower end of the side outer shielding plate 6 and connected with the interface 33 at the lower end of the side outer shielding plate 6, an inlet 16 is arranged on the collection bottom pipe 15 and extends to the outside of the transformer housing 1 and is connected with the output end of the oil pump 5, in order to further improve the cooling effect in the cooling box 2, heat dissipation plates 9 are arranged on the inside of the lower end of the cooling box 2 and located on both sides of the cooling pipe 11, mounting grooves 10 for wrapping the cooling pipe 11 are arranged on the opposite sides of the two heat dissipation plates 9, and heat dissipation fins 4 extending to the outside of the cooling box 2 are arranged on the end of the heat dissipation plate 9.

[0037] The above-mentioned channel for passing the heat conducting medium comprises at least two embodiments:

[0038] As shown in the drawings, Figures 7-8 the first embodiment of the channel comprises a heat dissipation flow channel 21 arranged on the inside of the side outer shielding plate 6, and the upper and lower ends of the heat dissipation flow channel 21 are connected with two interfaces 33 respectively.

[0039] As shown in the drawings, Figures 9-10 the second embodiment of the channel comprises a main heat dissipation flow channel 32 and a secondary heat dissipation flow channel 34 arranged on the inside of the side outer shielding plate 6, the upper and lower ends of the main heat dissipation flow channel 32 and the secondary heat dissipation flow channel 34 are connected with two interfaces 33 respectively, and only one is used normally.

[0040] The above-mentioned driving assembly also comprises at least two embodiments:

[0041] As shown in the drawings, Figure 7As shown in the first embodiment of the drive assembly and the first embodiment of the channel, the drive assembly includes a rack 26 provided at one end of the telescopic member 24, a sealing ball 22 rotatably provided at the inner side of the heat dissipation channel 21, a first through hole 23 provided on the sealing ball 22, and a gear 27 provided at one end of the sealing ball 22 and engaged with the rack 26. Thus, when the paraffin is melted and pushes the telescopic member 24 to move, the rack 26 is synchronously moved, and the gear 27 is rotated by the rack 26, and the sealing ball 22 is rotated by the gear 27, so that the first through hole 23 and the heat dissipation channel 21 are increased in the overlapping part, and the flow is increased.

[0042] As shown in the first embodiment of the drive assembly and the first embodiment of the channel, Figure 8 As shown in the second embodiment of the drive assembly and the first embodiment of the channel, the drive assembly includes a traction rod 31 rotatably provided at one end of the telescopic member 24, a sealing plate 29 movably and sealingly provided at one end of the heat dissipation channel 21, a second through hole 30 provided on the sealing plate 29, and one end of the traction rod 31 rotatably connected with one end of the sealing plate 29. Thus, when the paraffin is melted, the telescopic member 24 is moved, the inclination of the traction rod 31 is changed, the sealing plate 29 is moved, and the second through hole 30 and the heat dissipation channel 21 are increased in the overlapping part, and the flow is increased.

[0043] As shown in the first embodiment of the drive assembly and the first embodiment of the channel, Figure 9 As shown in the first embodiment of the drive assembly and the first embodiment of the channel, the sealing ball 22 is rotatably provided in the main heat dissipation channel 32 or the auxiliary heat dissipation channel 34. Initially, the sealing ball 22 blocks the main heat dissipation channel 32 or the auxiliary heat dissipation channel 34. When the temperature is high, the paraffin is melted and pushes the telescopic member 24 to move, and the sealing ball 22 is rotated by the rack 26 and the gear 27, so that the first through hole 23 on the sealing ball 22 is in line with the main heat dissipation channel 32 or the auxiliary heat dissipation channel 34, and the path of the heat conducting medium is increased.

[0044] As shown in the first embodiment of the drive assembly and the first embodiment of the channel, Figure 10 As shown in the second embodiment of the drive assembly and the first embodiment of the channel, the sealing plate 29 is movably provided at one end of the main heat dissipation channel 32 or the auxiliary heat dissipation channel 34. Initially, the main heat dissipation channel 32 or the main heat dissipation channel 32 is blocked by the sealing plate 29. When the temperature is high, the paraffin is melted, the inclination of the traction rod 31 is changed by the telescopic member 24, and the second through hole 30 and the main heat dissipation channel 32 or the auxiliary heat dissipation channel 34 are in line, and the path of the heat conducting medium is increased.

[0045] The working principle of the whole: first, the double-layer magnetic shielding structure set outside the transformer winding 17 works in coordination, the silicon steel shunt screen of the side inner shielding plate 18 and the end inner shielding plate 19 at the upper and lower ends diverts most of the leakage magnetic flux back to the main core, reducing the leakage from the source, and the residual leakage magnetic flux passing through the side inner shielding plate 18 and the end inner shielding plate 19 induces strong eddy current on the high-conductivity copper plate of the side outer shielding plate 6 and the end outer shielding plate 7, and the reverse magnetic field generated by the eddy current further cancels the leakage magnetic field, achieving high-efficiency shielding. At the same time, the heat dissipation system starts to work. Under normal working conditions of the photovoltaic system, the temperature in the core area of the transformer is generally below 85°C. At this time, the phase change material stored in the storage cavity 20 in the side outer shielding plate 6 is in a solid state, and the drive assembly driven by the phase change material switches the channel in the side outer shielding plate 6 to a small inner diameter or a short path mode. The oil pump 5 maintains basic circulation at low power consumption. The heat-conducting medium in the oil tank 8 enters the cooling pipe 11, is cooled through the cooperation of the cooling fin 4, the cooling plate 9 and the cooling fan 3, and then is pumped into the collection bottom pipe 15 through the oil pump 5, enters the channel through the interface 33 at the bottom of the side outer shielding plate 6, and then enters the collection top pipe 13 through the interface 33 at the upper end of the side outer shielding plate 6. Finally, it returns to the oil tank 8 again. When the photovoltaic system suddenly increases due to sudden weather changes and other reasons, causing the transformer load to impact and the temperature to rise and exceed the threshold, the phase change material melts and expands in volume due to heat, generating a mechanical thrust to drive the drive assembly to automatically enlarge the inner diameter of the channel or lengthen the channel path. A large amount of heat-conducting medium flushes the inner wall of the side outer shielding plate 6 where heat is concentrated, efficiently taking away the peak heat until the temperature falls and the phase change material re-solidifies, and then automatically restores to the energy-saving small inner diameter or short path mode, thereby completing a complete self-adaptive heat dissipation cycle without external intervention.

[0046] It should be noted that the oil pump 5 is a centrifugal fluid pump. In the energy-saving mode: no matter through the contraction of the channel inner diameter or the increase of the channel number, there will be a relatively high system resistance. In the face of such high resistance, the physical characteristics of the centrifugal oil pump determine that the outlet flow will decrease sharply. Although the pump needs to maintain a certain pressure, the large reduction in flow makes the product of total flow and pressure very small, so the actual operating power of the oil pump 5 also decreases to the lowest level, achieving energy saving. Conversely, when switching to the large inner diameter or multi-channel high-efficiency heat dissipation mode, the system resistance drops sharply, and the oil pump 5 can pump out a large flow of heat-conducting medium. At this time, although the pressure is not high, the large flow makes the product of flow and pressure large, and the oil pump 5 also enters a high-power state. Therefore, the present application actively reduces the workload of the oil pump 5 through high-resistance throttling.

[0047] The technical scope of the present application is not limited to the above description, and those skilled in the art can make various modifications and changes to the above embodiments without departing from the technical idea of the present application, and these modifications and changes should all belong to the protection scope of the present application.

Claims

1. A photovoltaic grid-tied low-loss step-up transformer with integrated magnetic shielding structure, characterized in that, The transformer shell (1) and the transformer winding (17) arranged in the inner cavity of the transformer shell (1), the side of the transformer winding (17) is provided with a side outer layer shielding plate (6); The side outer layer shielding plate (6) is provided with an adaptive heat dissipation structure, the adaptive heat dissipation structure comprises a channel arranged on the inner side of the side outer layer shielding plate (6) and used for passing the heat conduction medium, the upper end and the lower end of the side outer layer shielding plate (6) are respectively provided with an interface (33) in communication with the channel, the inner side of the side outer layer shielding plate (6) is provided with a storage cavity (20), the inner cavity of the storage cavity (20) is provided with a phase change material, the bottom end of the storage cavity (20) is provided with a movable cavity (28), the bottom end of the storage cavity (20) is provided with a telescopic piece (24) corresponding to the movable cavity (28), one end of the movable cavity (28) is provided with a driving assembly in linkage with the telescopic piece (24) and used for adjusting the inner diameter or the length of the channel. The side of the transformer shell (1) is provided with a cooling space used for cooling the heat conduction medium, the outer side of the transformer shell (1) is provided with an oil pump (5) corresponding to the cooling space, the interface (33) at the upper end of the side outer layer shielding plate (6) is in communication with the cooling space through a first pipeline, the interface (33) at the lower end of the side outer layer shielding plate (6) is connected with the output end of the oil pump (5) through a second pipeline, and the input end of the oil pump (5) is in communication with the cooling space, so that the circulation of the heat conduction medium can be realized. The cooling space comprises a cooling box (2) arranged on the side of the transformer shell (1), and the upper end of the inner side of the cooling box (2) is provided with an oil storage tank (8) used for storing the heat conduction medium, the bottom of the oil storage tank (8) is in communication with a cooling pipe (11), the lower end of the cooling pipe (11) is connected with the input end of the oil pump (5), and the cooling box (2) is provided with a cooling fan (3). The channel for passing the heat conduction medium comprises a heat dissipation flow channel (21) arranged on the inner side of the side outer layer shielding plate (6), and the upper end and the lower end of the heat dissipation flow channel (21) are respectively in communication with two interfaces (33). The channel for passing the heat conduction medium comprises a main heat dissipation flow channel (32) and a sub heat dissipation flow channel (34) arranged on the inner side of the side outer layer shielding plate (6), and the upper end and the lower end of the main heat dissipation flow channel (32) and the sub heat dissipation flow channel (34) are in communication with the interfaces (33) at the two ends.

2. The fusion of photovoltaic grid-tie low-loss boost transformer with magnetic shield structure according to claim 1, characterized in that: The driving assembly comprises a rack (26) arranged at one end of the telescopic piece (24), the inner side of the heat dissipation flow channel (21) is movably sealed with a sealing ball (22), the sealing ball (22) is provided with a first through hole (23), and one end of the sealing ball (22) is provided with a gear (27) engaged with the rack (26).

3. The fusion of photovoltaic grid-tie low-loss boost transformer with magnetic shield structure according to claim 1, characterized in that: The driving assembly comprises a traction rod (31) movably arranged at one end of the telescopic piece (24), the inner side of one end of the heat dissipation flow channel (21) is movably sealed with a sealing plate (29), the sealing plate (29) is provided with a second through hole (30), and one end of the traction rod (31) away from the telescopic piece (24) is movably connected with one end of the sealing plate (29).

4. The fusion of photovoltaic grid-tie low-loss boost transformer with magnetic shield structure according to claim 1, characterized in that: The driving assembly comprises a sealing ball (22) movably arranged in the main heat dissipation flow channel (32) or the auxiliary heat dissipation flow channel (34), the sealing ball (22) is provided with a first through hole (23), one end of the telescopic member (24) is provided with a gear rack (26), and one end of the sealing ball (22) is provided with a gear (27) engaged with the gear rack (26).

5. The fusion of photovoltaic grid-tie low-loss boost transformer with magnetic shield structure according to claim 1, characterized in that: The driving assembly comprises a sealing plate (29) movably arranged in the main heat dissipation flow channel (32) or the auxiliary heat dissipation flow channel (34), the sealing plate (29) is provided with a second through hole (30), one end of the telescopic member (24) is movably provided with a traction rod (31), and the end, away from the telescopic member (24), of the traction rod (31) is movably connected with one end of the sealing plate (29).

6. The low-loss grid-tie step-up transformer with integrated magnetic shield according to any of claims 2-5, characterized in that: An elastic member (25) for resetting the telescopic member (24) is arranged on the inner side of the movable cavity (28).

7. The low-loss grid-tie step-up transformer with integrated magnetic shield according to any of claims 2-5, characterized in that: The phase change material in the storage cavity (20) is paraffin.

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