Integrated uniform heat dissipation structure of high-power doubly-fed generator

Abstract

The application discloses an integrated heat dissipation structure of a high-power double-fed generator, which comprises a base, a cooler, a stator, a rotor and a stator terminal box. Wind baffles are installed at both ends of the stator, and the base inner cavity is divided into an outer cold air cavity and an inner heat exchange cavity. A gap is reserved between the wind baffles and the stator and the rotor coil end portion to form an end heat dissipation channel. Axial ventilation holes are formed in the base partition plate, and the stator end heat dissipation space is communicated with the heat exchange cavity. The stator terminal box is installed on the side surface of the base. The side surface of the base is provided with an air inlet hole for communicating the cold air cavity with the inside of the terminal box and an air outlet hole for communicating the inside of the terminal box with the outer circle of the stator core, so as to form a terminal box heat dissipation branch parallel to the main air path. The application can realize uniform cooling of the motor interior to eliminate local hot spots, and can also optimize the heat management of the stator terminal box synchronously, so as to effectively inhibit the temperature rise and abnormal heating of the cable in the box.

Description

Technical Field

[0001] This invention relates to the field of wind power generation technology, specifically to an integrated uniform heat dissipation structure for a high-power doubly-fed generator. Background Technology

[0002] As wind power generation develops towards larger capacity, higher reliability, and lower cost, the single-unit power of doubly-fed induction generators (DFIGs) is continuously increasing, leading to a sharp increase in internal losses (stator and rotor copper losses, core iron losses, stray losses, and mechanical losses). These losses are ultimately converted into heat, and if they cannot be dissipated in a timely and uniform manner, they will directly cause accelerated thermal aging of insulation materials, shorten winding life, and in severe cases, cause inter-turn short circuits, phase-to-phase breakdowns, or even burnout accidents. Meanwhile, wind turbines are typically installed in harsh environments such as deserts, plateaus, offshore areas, and Gobi deserts, where transportation is inconvenient and maintenance is difficult, placing extremely high demands on the long-term operational reliability and maintenance-free operation of the generators. Therefore, how to design an efficient, uniform, and reliable ventilation and heat dissipation system has become one of the core issues in the field of high-power DFIG technology.

[0003] Based on research and investigation in this technical field, the most similar implementation of existing high-power doubly-fed generators is patent CN202421521960.8, "Generator and Wind Turbine Generator Set." This patent can effectively improve the ventilation effect at the rotor winding ends and reduce the temperature rise at the rotor winding ends. However, after binding and impregnation, the gap at the stator winding ends is very small or even non-existent. The cooling air at the rotor ends cannot effectively pass through the stator winding ends to enter the cooler outlet, and uniform cooling of the stator winding ends cannot be achieved, especially at the winding edges far from the rotor. In addition, the partition plate is located near the middle of the stator winding ends, which also affects the stator three-phase conductive rings and stator cable outputs. This patent completely fails to address the structural design and thermal management of the stator junction box, resulting in high internal temperatures causing continuous cable heating, posing safety hazards such as insulation damage and short circuit faults. Summary of the Invention

[0004] To address the aforementioned issues, this invention discloses an integrated heat dissipation structure for a high-power doubly-fed generator. This structure not only achieves uniform cooling within the motor to completely eliminate localized hot spots, but also simultaneously optimizes the thermal management of the stator junction box. Without affecting the main cooling structure, it effectively suppresses temperature rise within the box and abnormal cable heating.

[0005] To achieve the above objectives, the present invention provides an integrated heat dissipation structure for a high-power doubly-fed generator, including a frame-type base, a cooler, a stator, a rotor, a stator junction box, and other accessories.

[0006] Specifically, the cooler is a direct-cooling cooler, where external cooling air enters the generator through the filter cotton on the cooler. The generator interior includes a stator and a rotor. The stator is directly mounted on the frame, and the rotor rests on the end cover. The frame, end cover, rotor, and cooler together form a large, sealed cavity.

[0007] The generator base has baffles installed at both ends of the stator. The baffles divide the cavity inside the generator base into two parts: cavity one is the space where external cooling air enters the generator but has not yet undergone heat exchange, i.e., the cold air cavity; cavity two is the space where heat exchange occurs inside the generator, i.e., the heat exchange cavity, including the stator, rotor, and their accessories. The baffles maintain a certain gap with the stator and the ends of the rotor coils, forming heat dissipation channels at both ends of the stator and rotor. The shape of the baffles guides the cooling air in cavity one into the rotor, rather than directly through the gap between the baffles and the rotor ends. The air flowing out from the gap at the rotor ends will further enter the heat dissipation space at the ends along the stator coils.

[0008] Both the stator and rotor are segmented structures, with gaps between segments forming radial cooling air channels. Axial through holes are provided in the rotor end plates and laminations to form axial ventilation channels. The rotor end coils are fixed using segmented end clamps, with gaps between the two end clamps and between the end clamps and the rotor core serving as channels for rotor end cooling air.

[0009] The base has axially oriented ventilation holes in the partition plate used to support the stator, which are connected to the heat dissipation spaces at both ends of the stator. The outer circumference of the stator core is connected to the air outlet of the cooler on the base, and all the hot air after heat exchange is discharged through the air outlet of the cooler.

[0010] The stator junction box is mounted on the side of the generator frame, which has wiring holes and ventilation holes. Cooling air from the cavity enters the junction box through the air inlet on the side of the generator frame, undergoes heat exchange, and then enters the outer circumference of the stator core through the air outlet on the side of the generator frame, and further exits through the cooler outlet. This forms a junction box heat dissipation branch connected in parallel with the main airflow of the generator body.

[0011] The present invention also provides a heat dissipation method based on the above-mentioned integrated heat dissipation structure, comprising the following steps:

[0012] Step 1: After being filtered by the filter cotton on the cooler, the external cooling air enters the first cavity. The baffle plate guides the cooling air in the first cavity into the rotor end. After passing through the gap between the two segmented end clamps and between the end clamps and the rotor core, the cooling air flows out from the rotor end and enters the heat dissipation space at both ends of the stator along the stator coil. Then, it enters the second cavity, i.e. the heat exchange cavity, through the ventilation holes on the frame partition. After exchanging heat with the stator and rotor, it is discharged through the air outlet of the cooler.

[0013] Step 2: Another part of the cooling air in the cavity enters the stator junction box through the air inlet on the side of the frame. After heat exchange through the terminal block and cable area, it flows out through the air outlet on the side of the frame to the outer circle of the stator core, and is further discharged through the air outlet of the cooler.

[0014] The beneficial effects of this invention are:

[0015] First, by setting the baffle plate on the outside of the stator coil end and maintaining a predetermined gap, the defect of the partition plate being located in the middle of the stator coil end in the existing patent is improved, making the cooling airflow of the stator coil end more uniform, eliminating the local overheating area caused by uneven wind speed, and solving the spatial arrangement problem of the three-phase conductive ring and stator cable routing at the coil end.

[0016] Secondly, by opening axial ventilation holes in the base partition, hot air from the stator end can smoothly enter the heat exchange chamber and eventually be discharged, significantly improving the heat dissipation efficiency of the stator end.

[0017] Third, by adding a junction box heat dissipation branch connected in parallel with the main air duct of the main body, no additional power source is needed. The existing air resources are used to effectively cool the junction box, keeping the temperature inside the box within the safe range allowed by the cable insulation. This eliminates the safety hazards such as continuous heating of the cable and the resulting insulation damage and short circuit faults. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of the overall structure of a specific embodiment provided by the present invention;

[0019] Figure 2 This is a schematic cross-sectional view (a) of the stator junction box airflow according to a specific embodiment of the present invention.

[0020] Figure 3 This is a schematic cross-sectional view (II) of the stator junction box airflow according to a specific embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of a base partition structure according to a specific embodiment of the present invention.

[0022] List of reference numerals in the attached diagram:

[0023] 1 Cooler; 2 Air inlet; 3 Air outlet; 4 Cavity 1; 5 Baffle plate; 6 Conductive ring; 7 Base partition; 8 Segmented end clamp; 9 Rotor; 10 Stator; 11 Cavity 2; 91 Ventilation hole in base partition; 12 Air inlet of stator junction box; 13 Air outlet of stator junction box; 14 Stator cable threading hole. Detailed Implementation

[0024] The present invention will be further illustrated below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inner" and "outer" refer to directions toward or away from the geometric center of a specific component, respectively.

[0025] like Figure 1 As shown, the present invention provides an integrated heat dissipation structure for a high-power doubly-fed generator, which mainly includes a frame-type base, a cooler 1, a stator 10, a rotor 9, an end cover, and a stator junction box.

[0026] The cooler 1 is installed above or outside the generator base. In this embodiment, the cooler 1 is a direct-cooling cooler, and its air inlet 2 is equipped with filter cotton to filter impurities in the external cooling air. The external cooling air enters the generator after passing through the filter cotton.

[0027] The stator 10 is directly fitted onto the inner wall of the frame, with an interference fit or key connection between the two. The rotor 9 is supported by end caps at both ends, and is located inside the stator 10 and coaxially arranged with the stator 10. The frame, end caps, rotor 9, and cooler 1 together form a large sealed cavity.

[0028] The base has baffles 5 installed at both axial ends of the stator 10. The baffles 5 are annular plate structures with their outer edges fixed to the inner wall of the base. The baffles 5 divide the sealed cavity into cavity 4 on the outer side, near the end cover, and cavity 11 on the inner side, between the two baffles. Cavity 4 is the space where the external cooling air has not yet exchanged heat with the motor components, i.e., the cold air cavity. Cavity 11 is the space where the cooling air exchanges heat with the stator 10, rotor 9, and their accessories, i.e., the heat exchange cavity.

[0029] Both the stator 10 and the rotor 9 are segmented structures, meaning that the stator core and the rotor core are composed of multiple laminations along the axial direction, and the gaps between the segments form radial cooling air channels. At the same time, the end plates and laminations of the rotor 9 have multiple axial through holes, which are distributed along the circumference of the rotor to form axial ventilation channels, allowing cooling air to pass through the rotor core axially.

[0030] like Figure 1 As shown, the end coils of the rotor 9 are fixed using segmented end clamps 8. The segmented end clamps 8 are arranged in segments along the circumference of the rotor end coils, with a certain gap between adjacent end clamps 8, and a certain gap between the end clamps 8 and the rotor core. These gaps together form the radial and axial flow channels for the cooling air at the rotor end.

[0031] like Figure 1As shown, the baffle plate 5 is mounted on the base at both ends of the stator 10. Specifically, the inner edge of the baffle plate 5 extends towards the coil end of the rotor 9, and the outer edge extends towards the coil end of the stator 10. A first predetermined gap is maintained between the baffle plate 5 and the coil end of the stator 10, and a second predetermined gap is maintained between the baffle plate 5 and the coil end of the rotor 9. Through its specific curved or inclined shape, the baffle plate 5 guides the cooling air within the cavity 4 into the end region of the rotor 9, preventing direct short-circuiting loss through the large gap between the baffle plate 5 and the rotor end.

[0032] The cooling air flowing out from the end gap of rotor 9 will, under the guidance of the baffle plate 5, flow further along the coil end of stator 10 and enter the heat dissipation space at both ends of stator 10, that is, the area between the baffle plate 5 and the stator coil end.

[0033] like Figure 1 and Figure 4 As shown, the base is provided with a base partition 7 for supporting the stator 10. The base partition 7 is an annular plate, the inner circle of which is adapted to and fixedly connected to the outer circle of the stator 10 core, and the outer circle of which is fixed to the inner wall of the base. A plurality of axial ventilation holes 91 are evenly opened along the circumference of the base partition 7.

[0034] The axial ventilation hole 91 connects the heat dissipation space at both ends of the stator 10 with the cavity 11. That is, hot air in the heat dissipation space at the end of the stator can enter the cavity 11 located in the middle of the motor through the ventilation hole 91 on the base partition 7.

[0035] like Figure 1 , Figure 2 and Figure 3 As shown, the stator junction box is installed on the side of the base 2. Three holes are provided on the side of the base within the installation area of ​​the stator junction box: a stator cable threading hole 14, a stator junction box air inlet 12, and a stator junction box air outlet 13.

[0036] The stator cable threading hole 14 allows high-current inlet and outlet cables to be led out from inside the motor to the junction box. The stator junction box air inlet 12 connects cavity 4 with the internal space of the stator junction box, and is located near the baffle plate 5 to ensure that the introduced air is cool air that has not yet been heated. The stator junction box air outlet 13 connects the internal space of the stator junction box with the outer circumference area of ​​the stator core, and is located near the base partition plate 7.

[0037] Combination Figures 1 to 3 The working process, i.e., the heat dissipation method, of this invention is as follows:

[0038] Main cooling airflow (step 1): External cooling air first passes through the filter cotton on the cooler 1 and then enters cavity 4. Guided by the baffle plate 5, the cooling air in cavity 4 enters the end area of ​​rotor 9. The cooling air flows sequentially through the gap between the two segmented end clamps 8 and the gap between the end clamps 8 and the rotor core, cooling the rotor end coils. The cooling air flowing out from the rotor end flows along the coil end of stator 10 under the constraint of the baffle plate 5, entering the heat dissipation space at both ends of stator 10, uniformly cooling the stator end coils. Subsequently, the cooling air enters cavity 11, i.e., the heat exchange chamber, through the axial ventilation hole 91 on the frame partition 7. In cavity 11, it fully exchanges heat with the stator 10 core and rotor 9 core, absorbing heat and becoming hot air. Finally, it flows through the channel between the outer circle of the stator core and the frame to the air outlet 3 of the cooler 1 and is discharged.

[0039] Junction Box Heat Dissipation Branch (Step 2): Under the action of the cooling fan, another portion of the cooling air in cavity 4 enters the stator junction box through the stator junction box inlet 12 on the side of the frame. This cold air blows directly onto the wiring terminals and outgoing cable area inside the junction box, forcing convection heat exchange for the Joule heat generated thereon. After heat exchange, the air temperature rises, and then flows out of the junction box through the stator junction box outlet 13 on the side of the frame, enters the outer circumference area of ​​the stator core, and merges with the hot air from the main airflow path, and is discharged together through the outlet 3 of the cooler 1. This forms a junction box heat dissipation circuit connected in parallel with the main airflow path of the generator body, and the entire process requires no additional power source.

[0040] The technical means disclosed in this invention are not limited to those disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features.

Claims

1. An integrated heat dissipation structure for a high-power doubly-fed generator, comprising a frame, a cooler (1), a stator (10), a rotor (9), and a stator junction box, wherein the stator (10) is mounted on the frame, and the rotor (9) is supported by an end cover, and the frame, end cover, rotor (9), and cooler (1) together form a sealed cavity, characterized in that: The base is equipped with baffles (5) at both ends of the stator (10) in the axial direction. The baffles (5) divide the sealed cavity into an outer cavity (4) and an inner cavity (11). A predetermined gap is maintained between the baffles (5) and the coil ends of the stator (10) and the coil ends of the rotor (9) to form end heat dissipation channels. The base partition (7) on the base for supporting the stator (10) has ventilation holes (91) in the axial direction. The ventilation holes (91) are connected to the heat dissipation spaces at both ends of the stator (10). The stator junction box is installed on the side of the base. The side of the base has a stator junction box air inlet (12) that connects the cavity (4) to the inside of the stator junction box, and a stator junction box air outlet (13) that connects the inside of the stator junction box to the air outlet (3) of the cooler (1).

2. The integrated heat dissipation structure of the high-power doubly-fed generator according to claim 1, characterized in that, The first cavity (4) is the space where the external cooling air has not yet undergone heat exchange after entering, and the second cavity (11) is the space where the cooling air exchanges heat with the stator (10) and rotor (9).

3. The integrated heat dissipation structure of the high-power doubly-fed generator according to claim 1, characterized in that, The end coil of the rotor (9) is fixed by segmented end clamps (8). There are gaps between the two end clamps (8) and between the end clamps (8) and the rotor core, which serve as channels for cooling air at the rotor end.

4. The integrated heat dissipation structure of the high-power doubly-fed generator according to claim 1, characterized in that, The stator (10) and rotor (9) are both segmented structures, and the gaps between the segments form radial cooling air channels; the end plates and laminations of the rotor (9) are provided with axial through holes to form axial ventilation channels.

5. The integrated heat dissipation structure of the high-power doubly-fed generator according to claim 1, characterized in that, The stator junction box outlet (13) connects the inside of the stator junction box with the outer circle of the stator core, and the outer circle of the stator core is connected to the outlet (3) of the cooler (1).

6. The integrated heat dissipation structure of the high-power doubly-fed generator according to claim 1, characterized in that, The cooler (1) is a direct-cooling cooler, and the external cooling air enters the generator through the filter cotton on the cooler (1).

7. An integrated heat dissipation method for a high-power doubly-fed generator, employing the integrated heat dissipation structure as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: External cooling air enters the cavity one (4) through the cooler (1). The baffle plate (5) guides the cooling air in the cavity one (4) into the end of the rotor (9). The cooling air flowing out from the end of the rotor (9) enters the heat dissipation space at both ends of the stator (10) along the coil end of the stator (10), and then enters the cavity two (11) through the ventilation hole (91) on the base partition (7). After heat exchange, it is discharged from the air outlet (3) of the cooler (1). Step 2: Another part of the cooling air in the cavity one (4) enters the stator junction box through the stator junction box air inlet (12) opened on the side of the base. After heat exchange through the terminal block and the outgoing cable area, it is discharged through the stator junction box air outlet (13) opened on the side of the base and discharged from the air outlet (3) of the cooler (1).

8. The integrated heat dissipation method for a high-power doubly-fed generator according to claim 7, characterized in that, In step 1, the external cooling air enters the cavity 1 (4) after being filtered by the filter cotton on the cooler (1).

9. The integrated heat dissipation method for a high-power doubly-fed generator according to claim 7, characterized in that, In step 1, when the baffle plate (5) guides the cooling air in the cavity (4) into the end of the rotor (9), the cooling air flows through the gap between the two segmented end clamps (8) and between the end clamps (8) and the rotor core.

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