Doubly-fed generator and wind power generation equipment

Abstract

The application discloses a doubly-fed generator and wind power generation equipment, the doubly-fed generator fixes an encoder shaft at one end of a rotating shaft, the encoder shaft is electrically connected with the rotating shaft, the outer periphery of the encoder shaft is provided with a conductive member fixed on a casing, the encoder shaft is electrically connected with the conductive member, and the conductive member is grounded. Namely, by integrating the grounding structure on the encoder shaft, the number of parts used by the grounding structure can be reduced, the construction of the grounding structure is simplified, and the grounding structure is higher in integration level and smaller in size. Moreover, since the encoder shaft generally has no load, the diameter of the encoder shaft can be flexibly adjusted to adapt to the structure of the conductive member. And meanwhile, the secondary influence of the smaller grounding structure on the vibration or displacement of the rotating shaft is smaller, so that the electric corrosion prevention function is continuously realized. In the operation process of the doubly-fed generator, induced current generated by the rotating shaft can be discharged to the ground through the encoder shaft and the conductive piece, so that electrocorrosion of the bearing is prevented.

Description

Technical Field

[0001] This application relates to the field of electrical machinery technology, and in particular to a doubly-fed generator and wind power generation equipment. Background Technology

[0002] In variable frequency motors, the high-frequency common-mode voltage generated by the inverter induces a voltage on the motor shaft through electromagnetic induction and capacitive coupling. When this voltage exceeds the insulation capacity of the bearing lubricant, current flows through the path formed by the shaft, bearing, and motor housing, leading to bearing damage. This type of bearing damage is commonly referred to as electro-corrosion. To prevent electro-corrosion damage, a grounding structure is typically installed to ground the shaft, thereby discharging the induced current and preventing electro-corrosion.

[0003] However, current methods for preventing electro-corrosion are relatively complex in structural design. Furthermore, in large motors, the induced current is typically much greater than in small motors (such as automotive motors), exceeding the limits that conventional grounding structures can withstand. In addition, small motors generally have simpler structures, while large motors are more complex. Moreover, the vibrations and offsets that may occur during the rotation of a large motor's shaft are far greater than those of a small motor, making it impossible for the grounding structure to maintain stability. Summary of the Invention

[0004] The purpose of this application is to provide a doubly-fed generator and wind power generation equipment that can prevent bearing electrolytic corrosion, and whose grounding structure has a simple overall structure, high integration and small size, thereby reducing the manufacturing cost of the doubly-fed generator and wind power generation equipment.

[0005] To address the aforementioned technical problems, the first aspect of this application provides a doubly-fed generator, comprising: chassis; A rotating shaft, a portion of which is disposed inside the housing; An encoder shaft is fixedly connected to one end of the rotating shaft and electrically connected to the rotating shaft. At least a portion of the encoder shaft is disposed inside the housing. A conductive element is arranged around the outer periphery of the encoder shaft and fixed to the housing. The conductive element is electrically connected to the encoder shaft and grounded.

[0006] The first aspect of this application describes a doubly-fed generator where an encoder shaft is fixed to one end of a rotating shaft and electrically connected to it. A conductive element fixed to the housing is provided around the outer periphery of the encoder shaft, and the encoder shaft and the conductive element are electrically connected and grounded. That is, by integrating the grounding structure onto the encoder shaft, the number of components used in the grounding structure can be reduced, simplifying its construction and resulting in a higher integration and smaller size. Furthermore, since the encoder shaft typically bears no load, its diameter can be flexibly adjusted to fit the structure of the conductive element. Simultaneously, a smaller grounding structure has less impact on the vibration or displacement of the rotating shaft, thus continuously providing protection against electro-corrosion. During the operation of the doubly-fed generator, the induced current generated by the rotating shaft can be discharged to ground through the encoder shaft and the conductive element, thereby preventing electro-corrosion of the bearings.

[0007] Optionally, the conductive component is a conductive bearing, which includes an inner bearing ring and an outer bearing ring. The inner bearing ring is fitted around the outer circumference of the encoder shaft, and the outer bearing ring is fitted around the outer circumference of the inner bearing ring. The outer bearing ring is connected to the housing. The encoder shaft, the inner bearing ring, and the outer bearing ring are electrically connected in sequence, and the outer bearing ring is grounded.

[0008] Optionally, the conductive bearing further includes a solid conductive ring sandwiched between the inner ring and the outer ring of the bearing to provide an electrical connection between them.

[0009] Optionally, the doubly-fed generator further includes a floating mounting structure having opposite ends, one end of which is connected to the housing, and the other end of which is connected to the bearing outer ring. The floating mounting structure is used to movably constrain the bearing outer ring to reduce stress transmission.

[0010] Optionally, the floating mounting structure includes an elastic element that surrounds the outer ring of the bearing and is sandwiched between the outer ring of the bearing and the housing.

[0011] Optionally, the housing and the outer ring of the bearing are clearance-fitted, and the surface of the housing facing the outer ring of the bearing is provided with a limiting groove arranged around the outer ring of the bearing. The elastic element is a rubber ring, and a portion of the rubber ring is embedded in the limiting groove.

[0012] Optionally, the floating mounting structure includes a plurality of torsion bars, which are arranged at intervals around the outer ring of the bearing, with one end of each torsion bar fixedly connected to the outer ring of the bearing and the other end of each torsion bar fixedly connected to the housing.

[0013] Optionally, the doubly-fed generator further includes a conductive ring, which is sleeved on the outer circumference of the bearing outer ring and sandwiched between the bearing outer ring and the housing. One end of the floating mounting structure is connected to the housing, and the other end of the floating mounting structure is connected to the conductive ring. The conductive ring is electrically connected to the bearing outer ring.

[0014] Optionally, the doubly-fed generator further includes a grounding metal component and a conductive strip. The grounding metal component is disposed inside the housing. One end of the conductive strip is electrically connected to the conductive ring, and the other end of the conductive strip is electrically connected to the grounding metal component.

[0015] Optionally, the doubly fed generator further includes an encoder, which includes a housing and a sensor disposed inside the housing. The housing is fixed to the generator housing, and the housing has a through hole. A portion of the encoder shaft extends into the housing through the through hole, and the sensor is used to detect the angular displacement of the encoder shaft.

[0016] Optionally, the conductive bearing further includes a first seal and a second seal. In the axial direction of the rotating shaft, the first seal and the second seal are disposed on opposite sides of the bearing outer ring and the bearing inner ring to form a sealing space with the bearing outer ring and the bearing inner ring, and the sealing space contains conductive fluid.

[0017] Optionally, the conductive component is a conductive brush, which includes a brush body and brush bristles connected to the brush body. The brush body is fixed to the housing and grounded, and the brush bristles are electrically connected to the encoder shaft. Alternatively, the conductive element may be a conductive rubber ring; or the conductive element may be a carbon brush.

[0018] Optionally, the rotating shaft has a shaft hole extending along its own axial direction, a portion of the encoder shaft extends into the shaft hole and is fixedly connected to the rotating shaft, and the conductive element is located outside the shaft hole.

[0019] A second aspect of this application provides a wind power generation device comprising a doubly-fed generator as described in any of the first aspects.

[0020] The wind power generation equipment of this application, by setting up the doubly fed generator as described in the first aspect, has the grounding structure described in the first aspect, thereby having a simpler construction, higher integration and smaller size grounding structure, which can maintain a stable current discharge function and continuously play the function of preventing electro-corrosion. During the operation of the doubly fed generator, the induced current generated by the rotating shaft can be discharged to the ground through the encoder shaft and conductive parts, thereby preventing electro-corrosion of the bearing.

[0021] The doubly-fed generator of this application has at least the following advantages over the prior art: The doubly-fed generator of this application integrates the grounding structure onto the encoder shaft, reducing the number of components used in the grounding structure, simplifying its construction, and resulting in a higher degree of integration and a smaller size. Furthermore, since the encoder shaft is typically unloaded, its diameter can be flexibly adjusted to suit the structure of the conductive components. Simultaneously, the smaller grounding structure has less secondary impact on shaft vibration or displacement, thus continuously providing protection against electro-corrosion. During generator operation, the induced current generated on the shaft can be discharged to ground through the encoder shaft and conductive components, thereby preventing electro-corrosion of the bearings. Attached Figure Description

[0022] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0023] Figure 1 This is a partial structural schematic diagram of the motor in an embodiment of this application; Figure 2 yes Figure 1 A top view of the motor shown; Figure 3 yes Figure 2 The diagram shows a cross-sectional view of the motor along the A-A' direction; Figure 4 yes Figure 2 The diagram shows the internal structure of the motor. Figure 5 yes Figure 4 A side view of the motor shown; Figure 6 yes Figure 5 The diagram shows a cross-sectional view of the internal structure along the B-B' direction. Figure 7 yes Figure 6 A magnified view of region C in the middle.

[0024] Explanation of reference numerals in the attached figures 1. Doubly fed generator; 11. Housing; 111. Grounding metal part; 112. Conductive strip; 113. Bearing housing; 12. Shaft; 12a. Wiring hole; 12b. Shaft hole; 121. Fixing base; 121a. Wire hole; 1211. Conductive part; 1212. Insulating part; 122. Slip ring; 13. Encoder shaft; 131. Extension part; 132. Central shaft part; 132a. Slot; 1321. Step part; 1322. Retaining ring; 133. Encoder; 1331. Housing; 14. Conductive part; 141. Inner bearing ring; 142. Outer bearing ring; 15. Floating mounting structure; 16. Conductive ring. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this application clearer, the various embodiments of this application will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been presented in the various embodiments of this application to facilitate a better understanding of the application. However, the technical solutions claimed in the claims of this application can be implemented even without these technical details and with various variations and modifications based on the following embodiments.

[0026] In the embodiments of this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated devices, elements, or components to having a specific orientation, or to be constructed and operated in a specific orientation.

[0027] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0028] Furthermore, the terms "installation," "setup," "equipped with," "opening," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0029] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, components, or parts (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, components, or parts. Unless otherwise stated, "a plurality of" means two or more.

[0030] Wind power generation equipment typically uses large motors, such as doubly-fed generators. During motor operation, the frequency converter can easily generate common-mode voltage. This common-mode voltage couples to the shaft through the motor's internal capacitors, inducing a voltage. Motor bearings are generally oil-lubricated, with grease forming an oil film on the bearing surface to reduce friction and protect the bearing and shaft. However, when the induced voltage on the shaft exceeds the insulation capacity of the oil film on the bearing surface, the oil film will break down. Due to the high resistance of the oil film, a large amount of heat is generated when the oil film breaks down, causing electrolytic corrosion of the bearing and ultimately compromising its integrity. Typically, a grounding structure can be installed inside the motor to ground the shaft. When an induced voltage is generated on the shaft, the grounding structure can be used to discharge the current, preventing current from passing through the bearing and causing electrolytic corrosion.

[0031] However, current grounding structures are typically used in small motors (vehicle motors). Small motors are compact, with small rotor shaft diameters and lengths, high machining precision, and minimal deformation with temperature changes. Furthermore, small motors have low loads, resulting in minimal rotor shaft vibration and deformation. Therefore, the requirements for axial force and coaxiality accuracy of the rotor shaft are relatively low during the assembly of the conductive bearings in small motors. However, doubly-fed induction generators for wind power are much larger, with rotor shaft lengths exceeding 3 meters. Simultaneously, the gearbox structure connected to the rotor shaft is complex, with numerous components, and the blades of wind power equipment are long and heavy, resulting in a very heavy load on the doubly-fed generator. During operation, the doubly-fed generator requires even greater current and voltage, directly leading to a significantly higher induced current on the shaft compared to the small motor, exceeding the design tolerance threshold. Considering all these factors, the grounding conductive bearing structure for small motors cannot be applied to doubly-fed induction generators for wind power.

[0032] To address the aforementioned technical problems, one embodiment of this application provides a doubly-fed generator that integrates the grounding structure onto the encoder shaft. This reduces the number of components used in the grounding structure, simplifies its construction, and results in a higher degree of integration and a smaller size. Furthermore, since the encoder shaft typically carries no load, its diameter can be flexibly adjusted to accommodate the structure of the conductive components. Simultaneously, the smaller grounding structure has less secondary impact on shaft vibration or displacement, thus continuously providing protection against electro-corrosion. During generator operation, the induced current generated by the shaft can be discharged to ground through the encoder shaft and conductive components, thereby preventing electro-corrosion of the bearings.

[0033] In this application, no specific limitations are made on the application field / scenario of the doubly-fed generator. To facilitate the description and understanding of the technical concept of this application, the following description uses the doubly-fed generator of a wind turbine as an example, but it is not stated that the following content applies only to this example.

[0034] The following is a detailed description of the implementation details of the doubly-fed generator and wind power generation equipment in this embodiment. The following content is only for the convenience of understanding and is not necessary for implementing this solution.

[0035] Please see also Figures 1 to 5 , Figure 1 This is a partial structural diagram of the motor in an embodiment of this application. Figure 2 yes Figure 1 The diagram shown is a top view of the motor. Figure 3 yes Figure 2 The diagram shows a cross-sectional view of the motor along the A-A' direction. Figure 4 yes Figure 2 The diagram shown is a schematic of the internal structure of the motor. Figure 5 yes Figure 4 The diagram shows a side view of the motor.

[0036] In the embodiments of this application, the doubly-fed generator 1 includes a housing 11, a rotating shaft 12, an encoder shaft 13, and a conductive element 14. A portion of the rotating shaft 12 is disposed inside the housing 11. The encoder shaft 13 is fixedly connected to one end of the rotating shaft 12 and electrically connected to the rotating shaft 12. At least a portion of the encoder shaft 13 is disposed inside the housing 11. The conductive element 14 is arranged around the outer periphery of the encoder shaft 13 and is fixed to the housing 11. The conductive element 13 is electrically connected to the encoder shaft 13 and grounded. It is understood that the end of the rotating shaft 12 with the encoder shaft 13 is disposed inside the housing 11.

[0037] In other words, by integrating the grounding structure onto the encoder shaft 13, the number of components used in the grounding structure can be reduced, simplifying its construction and resulting in a higher degree of integration and a smaller size. Furthermore, since the encoder shaft 13 typically has no load or a very small load, its diameter can be flexibly adjusted to fit the structure of the conductive element 14. Simultaneously, the smaller grounding structure has less secondary impact on the vibration or displacement of the shaft 12, allowing it to maintain a stable current discharge function. The induced current generated by the shaft 12 can be discharged to ground through the encoder shaft 13 and the conductive element 14, thereby preventing galvanic corrosion of the bearing and ensuring its continued anti-galvanic corrosion function.

[0038] In some embodiments, the housing 11 is provided with a grounded metal part 111, and the conductive part 14 is electrically connected to the grounded metal part 111. When the rotating shaft 12 generates an induced current, the induced current is transmitted sequentially from the rotating shaft 12 to the encoder shaft 13, the conductive part 14 and the grounded metal part 111, thereby realizing the discharge of the induced current.

[0039] In some embodiments, the grounding metal element 111 is electrically connected to the conductive element 14 via a conductive strip 112. The conductive strip 112 has a large cross-sectional area, which helps to increase the amount of current passing through the conductive strip 112 per unit time, thereby improving the current discharge efficiency.

[0040] In some embodiments, a mounting base 121 can be provided at the end of the rotating shaft 12, and the encoder shaft 13 can be fixed to the mounting base 121 by means of screws / bolts, so that the encoder shaft 13 rotates synchronously during the rotation of the rotating shaft 12, so that the encoder can detect parameters such as the rotational speed / angular displacement of the rotating shaft 12.

[0041] Typically, a doubly-fed generator 1 requires a three-phase circuit for output, resulting in relatively large conductors (not shown). If the conductors are directly wound around the outer circumference of the shaft 12, induced currents / capacitors may form between different conductors, affecting the reliability of the circuit. Furthermore, directly winding the conductors around the shaft 12 also increases the size of the doubly-fed generator 1. Therefore, in some embodiments, the shaft 12 has a wiring hole 12a extending at an angle to its own axis at one end with a mounting base 121, and a shaft hole 12b connecting the wiring hole 12a and extending along its own axial direction. The mounting base 121 is fixed to the end of the shaft hole 12b, and the mounting base 121 has a through hole 121a connecting to the shaft hole 12b. Conductors electrically connecting the rotor coils to the outer circumference of the shaft 12 can extend from the wiring hole 12a into the shaft hole 12b, then extend along the axial direction of the shaft 12 to the mounting base 121, and exit through the through hole 121a of the mounting base 121 to the outside of the shaft 12.

[0042] Of course, in some other embodiments, a portion of the encoder shaft 13 can directly extend into the shaft hole 12b and be fixed to the inner wall of the shaft hole 12b, with the conductive element 14 located on the portion of the encoder shaft 13 outside the shaft hole 12b. In this case, the aforementioned fixing seat 121 may not be provided. The following description uses the example of a fixing seat 121 at the end of the rotating shaft 12, but it is not intended to imply that the following content applies only to this example.

[0043] It should be understood that, due to its large size, the doubly-fed generator 1 has a heavy load on its shaft 12. During operation, the shaft 12 experiences significant vibration, and the high load and high-temperature outdoor working environment can easily cause substantial deformation (including stress deformation and thermal deformation) in the shaft 12. Therefore, if the grounding structure is directly placed on the shaft 12, it is easily compressed due to the vibration and / or deformation of the shaft 12, or experience poor electrical contact, leading to damage or failure of the grounding structure. In contrast, the encoder shaft 13 has no load and its size is much smaller than that of the shaft 12. Therefore, the encoder shaft 13 is unlikely to deform under stress, and its thermal deformation is also very small, having minimal impact on the stability of the grounding structure and ensuring long-term stable current discharge.

[0044] In some embodiments, to prevent the mounting bracket 121 from having an electrical effect on the conductor and to prevent the insulation layer of the conductor from being damaged due to friction from the mounting bracket 121, thereby causing a short circuit through the mounting bracket 121, the mounting bracket 121 is configured to be insulating, that is, the mounting bracket 121 is made of insulating material. In some embodiments, the mounting bracket 121 may be made of heat-resistant insulating material.

[0045] Understandably, in order for the induced current generated by the rotating shaft 12 to be conducted to the encoder 13 through the mounting base 121, the mounting base 121 is configured to have a conductive portion and an insulating portion. Specifically, the mounting base 121 includes a conductive portion 1211 and an insulating portion 1212. The conductive portion 1211 is fixedly connected to the rotating shaft 12, and the insulating portion 1212 is fixedly connected to the conductive portion 1211. The insulating portion 1212 is provided with the aforementioned through-hole 121a, and the encoder shaft 13 is fixedly connected to the conductive portion 1211. For example, the conductive portion 1211 is annular, and the insulating portion 1212 is a circular plate component embedded within the annular conductive portion 1211.

[0046] In some embodiments, a slip ring 122 is fitted around the outer periphery of the end of the rotating shaft 12 where the fixed seat 121 is located, and the slip ring 122 is fixedly connected to the rotating shaft 12. When the induced current is discharged, the current is transmitted from the rotating shaft 12 to the slip ring 122, then from the slip ring 122 to the conductive part 1211 and the encoder shaft 13, and finally discharged to the ground via the conductive element 14, thereby achieving the purpose of preventing electro-corrosion.

[0047] Of course, in some other embodiments, the mounting base 121 can be made of metal. The inner wall and opening edge of the wire hole 121a can be designed for low friction. For example, the inner wall of the wire hole 121a can be polished or coated (including with an insulating film), and the openings at both ends of the wire hole 121a can be rounded to reduce friction between the wire hole 121a and the wire.

[0048] In some embodiments, the encoder shaft 13 may include an extension 131 and a central shaft portion 132. The extension 131 is fixedly connected to the aforementioned mounting base 121, and the central shaft portion 132 is fixedly connected to the end of the extension 131 away from the mounting base 121. The central shaft portion 132 is coaxially arranged with the rotating shaft 12. A conductive element 14 is attached to the central shaft portion 132. It is understood that since the wire extends through the mounting base 121 and out of the rotating shaft 12, by providing the extension 131, the central shaft portion 132 is offset from the mounting base 121 in the axial direction of the rotating shaft 12, thus avoiding interference between the central shaft portion 132 and the conductive element.

[0049] In some embodiments, there are multiple extensions 131, and the multiple extensions 131 are arranged at circumferential intervals along the rotating shaft 12, and the central shaft portion 132 is fixedly connected to the ends of the multiple extensions 131 away from the rotating shaft 12.

[0050] It should be noted that this application does not impose any special limitations on the shape and size of the encoder shaft 13. Any small shaft with a diameter smaller than that of the rotating shaft that is extended from the end of the rotating shaft 12 can be regarded as the encoder shaft 13.

[0051] It is understandable that an encoder 133 is provided at the end of the encoder shaft 13 away from the rotating shaft 12. The encoder 133 obtains the corresponding parameters of the rotating shaft 12 by detecting parameters such as the rotational speed / angular displacement of the encoder shaft 13.

[0052] In some embodiments, the encoder 133 is located outside the housing 11, that is, on the side of the housing 11 opposite to the rotating shaft 12. In other embodiments, the encoder 133 may also be located inside the housing 11, and this application does not specifically limit this.

[0053] Taking the encoder 133 located outside the housing 11 as an example, the housing 11 has a through hole 11a through which the encoder shaft 13 extends to the outside of the housing 11. The encoder 133 includes a housing 1331 and a sensor (not shown) disposed inside the housing 1331. The encoder shaft 13 extends into the housing 1331, and the housing 1331 is fixed to the housing 11. The sensor detects the angular displacement of the encoder shaft 13 to obtain the angular displacement of the rotating shaft 12 during rotation.

[0054] In some embodiments, the conductive element 14 is a conductive bearing, which is sleeved on the outer periphery of the central shaft portion 132 and electrically connected to the grounded metal element 111. It is understood that the housing 11 can be directly assembled with the conductive bearing, or a bearing seat 113 can be provided on the housing 11 for assembly with the conductive bearing. The following description uses the example of a housing 11 having a bearing seat 113, but this should not be construed as a limitation of the present solution.

[0055] In other embodiments, the conductive element 14 is a conductive brush, which is disposed on the housing 11 and surrounds the outer periphery of the encoder shaft 13. The conductive brush includes a fixed part surrounding the outer periphery of the encoder shaft 13, and bristles disposed between the fixed part and the encoder shaft 13. The fixed part is electrically connected to the conductive strip 112, and the bristles abut against the outer peripheral surface of the encoder shaft 13. In this way, the current conducted to the encoder shaft 13 can be conducted to the conductive strip 112 through the bristles and the fixed part. Since the diameter of the encoder shaft 13 is small, the linear velocity of its surface is small during rotation, which reduces friction on the bristles and extends the service life of the bristles. At the same time, the doubly-fed generator 1 usually also has carbon brushes inside. The carbon brushes will generate carbon dust due to wear caused by the friction of the rotating shaft 12. By setting the conductive element 14 as a conductive brush, its bristles can act as a filter, preventing carbon dust from drifting to the outside of the doubly-fed generator 1, which helps to reduce environmental pollution.

[0056] In some embodiments, the conductive element 14 can also be configured as a conductive structure such as a carbon brush or a conductive rubber body. Similarly, since the surface linear velocity of the encoder shaft 13 is relatively low during rotation, wear on the conductive element 14 can be reduced.

[0057] It should be noted that the following description uses conductive component 14 as a conductive bearing, but it is not intended to imply that the following content applies only to this example.

[0058] Please see also Figure 6 and Figure 7 , Figure 6 yes Figure 5 The diagram shows a cross-sectional view of the internal structure along the B-B' direction. Figure 7 yes Figure 6 A magnified view of region C in the middle.

[0059] In some embodiments, to ensure that the conductive bearing is fixed in the axial direction of the central shaft portion 132, a stepped portion 1321 can be formed on the outer periphery of the central shaft portion 132, so that the conductive bearing abuts against the stepped portion 1321, and the other side of the conductive bearing abuts against the housing 11. In some other embodiments, the central shaft portion 132 is also provided with a groove 132a extending circumferentially, the groove 132a and the stepped portion 1321 are spaced apart in the axial direction of the central shaft portion 132, and a retaining ring 1322 is fixedly held in the groove 132a, the retaining ring 1322 is used to cooperate with the stepped portion 1321 to fix the conductive bearing axially.

[0060] Specifically, the conductive bearing includes an inner ring 141 and an outer ring 142. The inner ring 141 is fitted around the outer circumference of the central shaft portion 132 and is fixedly connected to the central shaft portion 132. The outer ring 142 is fitted around the outer circumference of the inner ring 141 and is rotatable relative to the inner ring 141. The outer ring 142 is electrically connected to a grounded metal component 111. The inner ring 141 and the outer ring 142 are electrically connected, allowing current to be conducted from the inner ring 141 to the outer ring 142. It is understood that the stepped portion 1321 and the retaining ring 1322 are located on opposite sides of the inner ring 141 in the axial direction to limit and fix the inner ring 141.

[0061] In some embodiments, the conductive bearing is a sealed bearing, containing conductive grease / fluid. This lubrication not only lubricates the inner ring 141 and outer ring 142 but also electrically connects them via the conductive grease. The conductive bearing can be a ball bearing or a ballless bearing.

[0062] Since the vibration transmitted from the shaft 12 to the encoder 13 is very small, and the encoder shaft 13 has no load or a very small load, the influence of the encoder shaft 13 on the main shaft 12 is negligible. Therefore, in some embodiments, the conductive bearing 14 further includes a solid conductive ring (not shown) sandwiched between the inner ring 141 and the outer ring 142 of the bearing, which electrically connects the inner ring 141 and the outer ring 142. Optionally, the solid conductive ring can be a ring-shaped component with conductive properties, such as a metal ring or a conductive rubber ring. Preferably, the solid conductive ring can be a conductive rubber ring, so that when the encoder shaft 13 experiences a small vibration or displacement, the conductive rubber ring itself can absorb or buffer the corresponding mechanical changes through elastic deformation.

[0063] Understandably, the conductive bearing is provided with a first seal (not shown) and a second seal (not shown) spaced apart in the axial direction. The bearing inner ring 141, the bearing outer ring 142, the first seal and the second seal together form a sealing space, and conductive fluids such as conductive grease / conductive liquid are provided in the sealing space.

[0064] In some embodiments, the outer peripheral surface of the bearing outer ring 142 abuts against the bearing housing 113 to position the conductive bearing radially. Specifically, the bearing housing 113 is disposed around the outer periphery of the bearing outer ring 142.

[0065] In some embodiments, considering that the encoder shaft 13 may experience vibration, deformation, or other factors, the doubly-fed generator 1 also includes a floating mounting structure 15. The floating mounting structure 15 has two opposing ends, one end of which is connected to the housing 11, and the other end is connected to the bearing outer ring 142. The floating mounting structure 15 allows relative movement between the bearing outer ring 142 and the housing 11. When the encoder shaft 13 experiences vibration and / or deformation, it can reduce the stress transmission between the bearing outer ring 142 and the housing 11, preventing the bearing outer ring 142 from being subjected to excessive axial and radial forces, thereby preventing deformation or damage to the conductive bearing.

[0066] In some embodiments, the floating mounting structure 15 includes an elastic element that surrounds the outer periphery of the bearing outer ring 142 and is sandwiched between the bearing outer ring 142 and the bearing housing 113. The elastic element allows the bearing outer ring 142 and the bearing housing 113 to move relative to each other, at least radially. When the encoder shaft 13 vibrates or deforms, the elastic element can absorb energy and buffer stress, thereby reducing stress transmission and lowering the risk of damage to the conductive bearing.

[0067] Optionally, the elastic element can be an O-ring, a metal spring, a spring, a compression spring, or other elastic components. The following explanation uses an O-ring as an example, but it is not intended to imply that the following content applies only to this example.

[0068] In some embodiments, the bearing housing 113 and the bearing outer ring 142 are clearance-fitted, and the bearing housing 113 has a limiting groove 113a surrounding the bearing outer ring 142 on its surface facing the bearing outer ring 142, with a portion of the rubber ring embedded in the limiting groove 113a. Thus, when the encoder shaft 13 vibrates or deforms, the encoder shaft 13 can compress the rubber ring, causing it to deform under pressure and absorb some energy, achieving buffering and reducing the force transmitted to the bearing housing 113, thereby preventing damage to the conductive bearing.

[0069] In some embodiments, the dimension of the limiting groove 113a in the axial direction of the rotating shaft 12 is slightly larger than the dimension of the rubber ring in the axial direction of the rotating shaft 12. In this way, when the encoder shaft 13 becomes longer due to deformation, the rubber ring can roll and shift within the axis of the rotating shaft 12 in the limiting groove 113a under the action of the encoder shaft 13, preventing the encoder shaft 13 from driving the conductive bearing to move, thereby preventing damage to the conductive bearing.

[0070] Of course, multiple rubber rings can be provided, and the multiple rubber rings are arranged at intervals along the axial direction of the encoder shaft 13. Adaptively, multiple limiting grooves 113a are provided, and the multiple limiting grooves 113a are arranged corresponding to the rubber rings.

[0071] In some other embodiments, the floating mounting structure 15 may include a plurality of torsion bars (not shown) arranged circumferentially around the outer ring 142 of the bearing, with one end of each torsion bar connected to the outer ring 142 and the other end connected to the bearing housing 113. The torsion of the torsion bars provides elastic support, and when the encoder shaft 13 vibrates or deforms, the elastic support of the torsion bars can function as vibration damping or buffering adjustment.

[0072] In some embodiments, the doubly-fed generator 1 further includes a conductive ring 16, which is sleeved on the outer periphery of the bearing outer ring 142 and engages with the outer peripheral surface of the bearing outer ring 142 and the two axially oriented sides of the bearing outer ring 142. The outer peripheral surface of the conductive ring 16 abuts against the bearing housing 113, and the conductive ring 16 is electrically connected to the grounding metal component 111. It is understood that one end of the floating mounting structure 15 is connected to the conductive ring 16, and the other end is connected to the bearing housing 113. By providing the conductive ring 16 and engaging it with the outer peripheral surface and the two axially oriented sides of the bearing outer ring 142, the electrical contact area is increased, which helps to improve the efficiency of current discharge and reduce the pressure of current conduction. Of course, in other embodiments, when the area of ​​the outer peripheral surface of the bearing outer ring 142 is large enough, the conductive ring 16 can be omitted.

[0073] In some embodiments, the radial dimension of the conductive bearing can be increased by increasing the diameter of the portion of the encoder shaft 13 corresponding to the conductive bearing, and the conductive strip 112 can be directly electrically connected to the outer ring 142 of the bearing, thereby omitting the conductive ring 16.

[0074] The second aspect of this application provides a wind power generation device (not shown), which includes the motor 1 described in the first aspect.

[0075] Wind power generation equipment can be electrically connected to energy storage devices, power grids, and electrical equipment. The electrical energy generated by wind power can be stored in energy storage devices, connected to the power grid for power supply, or directly used by electrical equipment.

[0076] The doubly-fed generator and wind power generation equipment provided in the embodiments of this application have been described in detail above. Specific examples have been used in this document to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the ideas of this application. There may be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A doubly-fed generator, characterized in that, include: chassis; A rotating shaft, a portion of which is disposed inside the housing; An encoder shaft is fixedly connected to one end of the rotating shaft and electrically connected to the rotating shaft. At least a portion of the encoder shaft is disposed inside the housing. A conductive element is arranged around the outer periphery of the encoder shaft and fixed to the housing. The conductive element is electrically connected to the encoder shaft and grounded.

2. The doubly-fed generator according to claim 1, characterized in that, The conductive component is a conductive bearing, which includes an inner bearing ring and an outer bearing ring. The inner bearing ring is fitted around the outer circumference of the encoder shaft, and the outer bearing ring is fitted around the outer circumference of the inner bearing ring. The outer bearing ring is connected to the housing. The encoder shaft, the inner bearing ring, and the outer bearing ring are electrically connected in sequence, and the outer bearing ring is grounded.

3. The doubly-fed generator according to claim 2, characterized in that, The conductive bearing also includes a solid conductive ring, which is sandwiched between the inner ring and the outer ring of the bearing to make the inner ring and the outer ring of the bearing electrically connected.

4. The doubly-fed generator according to claim 2, characterized in that, The doubly-fed generator also includes a floating mounting structure having two opposing ends. One end of the floating mounting structure is connected to the housing, and the other end is connected to the outer ring of the bearing. The floating mounting structure is used to movably constrain the outer ring of the bearing to reduce stress transmission.

5. The doubly-fed generator according to claim 4, characterized in that, The floating mounting structure includes an elastic element that surrounds the outer ring of the bearing and is sandwiched between the outer ring of the bearing and the housing.

6. The doubly-fed generator according to claim 5, characterized in that, The housing is clearance-fitted with the outer ring of the bearing, and the surface of the housing facing the outer ring of the bearing has a limiting groove arranged around the outer ring of the bearing. The elastic element is a rubber ring, and a portion of the rubber ring is embedded in the limiting groove.

7. The doubly-fed generator according to claim 4, characterized in that, The floating mounting structure includes multiple torsion bars, which are arranged at intervals around the outer ring of the bearing. One end of each torsion bar is connected to the outer ring of the bearing, and the other end of each torsion bar is connected to the housing.

8. The doubly-fed generator according to claim 4, characterized in that, The doubly fed generator also includes a conductive ring, which is sleeved on the outer circumference of the bearing outer ring and sandwiched between the bearing outer ring and the housing. One end of the floating mounting structure is connected to the housing, and the other end of the floating mounting structure is connected to the conductive ring. The conductive ring is electrically connected to the bearing outer ring.

9. The doubly-fed generator according to claim 8, characterized in that, The doubly-fed generator also includes a grounding metal component and a conductive strip. The grounding metal component is located inside the housing. One end of the conductive strip is electrically connected to the conductive ring, and the other end of the conductive strip is electrically connected to the grounding metal component.

10. The doubly-fed generator according to any one of claims 2-9, characterized in that, The doubly fed generator also includes an encoder, which includes a housing and a sensor disposed inside the housing. The housing is fixed to the casing, and the casing has a through hole. A portion of the encoder shaft extends into the housing through the through hole, and the sensor is used to detect the angular displacement of the encoder shaft.

11. The doubly-fed generator according to any one of claims 2-9, characterized in that, The conductive bearing further includes a first seal and a second seal. In the axial direction of the shaft, the first seal and the second seal are disposed on opposite sides of the outer ring and the inner ring of the bearing to form a sealing space with the outer ring and the inner ring of the bearing. The sealing space contains conductive fluid.

12. The doubly-fed generator according to claim 1, characterized in that, The conductive component is a conductive brush, which includes a brush body and brush bristles connected to the brush body. The brush body is fixed to the housing and grounded. The brush bristles are electrically connected to the encoder shaft. Alternatively, the conductive element may be a conductive rubber ring; or the conductive element may be a carbon brush.

13. The doubly-fed generator according to any one of claims 1-9, characterized in that, The rotating shaft has a shaft hole extending along its own axial direction, a portion of the encoder shaft extends into the shaft hole and is fixedly connected to the rotating shaft, and the conductive element is located outside the shaft hole.

14. A wind power generation device, characterized in that, Including the doubly-fed generator as described in any one of claims 1-13.

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