Variable frequency variable force electromagnetic brake for wind power generator

Abstract

The application belongs to the technical field of wind power generation equipment braking, and particularly relates to a variable-frequency variable-force electromagnetic brake of a wind driven generator, which comprises a variable-frequency electromagnetic braking unit, a working condition detection unit and a central control unit, the variable-frequency electromagnetic braking unit comprises a shell, an electromagnetic coil arranged on the shell, a braking spring arranged in the shell and staggered with the electromagnetic coil and a conversion braking mechanism arranged on the top surface of the shell and in contact with the braking spring, a shaft sleeve is installed on the conversion braking mechanism, a motor shaft is arranged in the shaft sleeve, the working condition detection unit is used for collecting the running working condition parameters of the wind driven generator in real time, and the central control unit is used for receiving the working condition parameter electric signals transmitted by the working condition detection unit and judging the current running state of the wind driven generator. The application can solve the problems that the traditional electromagnetic brake is difficult to realize smooth braking transition and is prone to generate large impact current and braking impact.

Description

Technical Field

[0001] This invention belongs to the field of braking technology for wind power generation equipment, and in particular relates to a variable frequency and variable force electromagnetic brake for wind turbine generators. Background Technology

[0002] In the wind power industry, brakes are key safety components of wind turbines, and their performance directly affects the operational safety and service life of the turbines. Currently, the brakes used in wind turbines mainly include mechanical brakes and traditional electromagnetic brakes.

[0003] Mechanical brakes achieve braking through mechanical friction between brake pads and brake discs. However, this braking method has many drawbacks. On the one hand, mechanical friction leads to severe wear on the brake pads and brake discs, requiring frequent replacement of parts, which not only increases maintenance costs but also prolongs the downtime of wind turbines, affecting power generation efficiency. On the other hand, mechanical braking generates a large amount of heat, which can easily cause thermal fade of braking components, resulting in decreased braking performance. In emergency braking situations, there is even a risk of brake failure, seriously threatening the safe operation of wind turbines.

[0004] While traditional electromagnetic brakes avoid some of the problems caused by mechanical friction, they mostly use a fixed frequency control method, which cannot be flexibly adjusted according to the actual operating conditions of the wind turbine (such as changes in speed, load, and wind speed). During the start-up, shutdown, and speed changes caused by wind speed fluctuations, traditional electromagnetic brakes are difficult to achieve a smooth braking transition, which can easily generate large inrush currents and braking shocks. This can not only cause additional mechanical stress on the transmission system, main shaft, and other components of the wind turbine, shortening the service life of the equipment, but may also affect the stable operation of the power grid.

[0005] Therefore, developing a variable frequency and variable force electromagnetic brake that can adaptively adjust according to the actual operating conditions of wind turbines to achieve smooth, efficient, and low-loss braking, while also possessing high safety and reliability, has become an urgent technical problem to be solved in the field of wind power equipment. Summary of the Invention

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution: This invention relates to a variable frequency electromagnetic brake for a wind turbine generator, comprising a variable frequency electromagnetic braking unit, a working condition detection unit, and a central control unit. The variable frequency electromagnetic braking unit includes a housing, an electromagnetic coil mounted on the housing, a brake spring mounted inside the housing and offset from the electromagnetic coil, and a switching braking mechanism mounted on the top surface of the housing and in contact with the brake spring. A bushing is mounted on the switching braking mechanism, and a motor shaft is mounted inside the bushing. The operating condition detection unit is used to collect the operating condition parameters of the wind turbine in real time. The central control unit is used to receive electrical signals of operating parameters transmitted by the operating condition detection unit, analyze and process the parameters through the operating condition analysis algorithm, and determine the current operating status of the wind turbine. A frequency converter is connected in series in the power supply circuit of the electromagnetic coil, and the frequency converter is electrically connected to the central control unit.

[0007] Preferably, the switching braking mechanism includes an annular armature mounted on the top surface of the housing, a brake disc placed on the upper surface of the annular armature, a brake gear disc mounted on the brake disc and cooperating with a bushing, and a friction disc connected to the housing via a connecting member; the electromagnetic coil and the brake spring are both installed in an embedded manner, and the electromagnetic coil adopts a multi-winding structure.

[0008] Preferably, the connector adopts a screw structure, and a sleeve is sleeved on the connector located between the friction disc and the housing, and the two ends of the sleeve abut against the surfaces of the housing and the friction disc to limit the distance between the friction disc and the housing; the sleeve slides in conjunction with the sliding hole opened on the annular armature, and the axial length of the sleeve is the same as the sum of the thickness of the brake disc, the brake tooth disc and the annular armature and the distance of the brake air gap A formed between the annular armature and the housing.

[0009] Preferably, the outer ring surface of the bushing is formed with an annular cam, and the annular cam extends to the upper surface of the annular armature. The outer ring surface of the annular cam is formed with external teeth, and the inner ring surface of the brake disc is formed with internal teeth that mesh with the external teeth. The length of the external teeth is greater than the length of the internal teeth.

[0010] Preferably, the bottom end of the bushing extends into the central hole of the housing, and the outer ring surface of the bushing is provided with an annular groove; the inner wall of the central hole of the housing is provided with at least one recessed square groove, and each recessed square groove is provided with a push-limiting component for axially limiting the bushing.

[0011] Preferably, the inner wall of the recessed square groove is inclined, and the pushing and limiting assembly includes an inclined push block installed in the recessed square groove, a limiting insert block installed in the recessed square groove and in contact with the vertical surface of the inclined push block, a push screw threaded to the bottom of the recessed square groove, and a pushing and misaligning assembly connecting the push screw and the inclined push block; a threaded hole for the push screw to be connected is provided between the bottom of the housing and the bottom of the recessed square groove; a radial sliding groove is provided radially at the bottom of the recessed square groove, and a moving block connected to the limiting insert block is movably installed in the radial sliding groove, and a return spring is connected between the moving block and the groove wall of the radial sliding groove.

[0012] Preferably, the pushing and misaligning assembly includes a T-slot radially formed on the bottom surface of the inclined push block, a T-block movably installed in the T-slot, a push rod connected to the bottom of the T-block, and a support ring sleeved on the outside of the push rod; a countersunk hole is formed at the bottom of the recessed square groove where it aligns with the threaded hole, the push rod is inserted into the countersunk hole, and the support ring is connected to the bottom of the countersunk hole by a spring.

[0013] Preferably, the operating condition detection unit includes a speed sensor, a load sensor, and a wind speed sensor; the speed sensor is installed on the main shaft of the wind turbine to detect the real-time speed of the main shaft; the load sensor is installed at the output end of the generator to detect the real-time load current and power of the generator; the wind speed sensor is installed on the top of the nacelle of the wind turbine to detect the real-time wind speed of the external environment; the operating condition detection unit converts the collected speed, load, and wind speed operating condition parameters into electrical signals and transmits them to the central control unit in real time.

[0014] Preferably, the central control unit uses an embedded microprocessor as the core control chip and has built-in operating condition analysis algorithms and braking strategy database.

[0015] The present invention has the following beneficial effects: 1. This solution combines a variable frequency electromagnetic braking unit, a working condition detection unit, and a central control unit. The working condition detection unit can collect the generator speed, load, and wind speed working condition parameters in real time. The central control unit can generate corresponding frequency control signals based on the collected different working condition data. The variable frequency controller can adjust the current frequency and current intensity of the input electromagnetic coil, thereby changing the magnitude of the electromagnetic attraction generated by the electromagnetic coil, and thus achieving precise adjustment of braking torque. This solves the problem that traditional electromagnetic brakes are difficult to achieve smooth braking transition and are prone to generating large inrush current and braking shock. 2. This solution utilizes at least three sleeves and screws evenly distributed around the circumference. The sleeves not only provide axial height limiting support for the friction disc, but also allow for rapid adjustment of the electromagnetic brake's braking effect on the motor shaft even if one of the friction surfaces in contact with the friction disc, annular armature, and brake disc wears down, affecting the braking force of the brake spring on the brake disc via the annular armature. This is achieved by simply replacing the sleeve with one of shorter axial heights, reducing the size of the brake air gap A formed between the annular armature and the housing. This eliminates the need for frequent component replacements, reducing maintenance costs and preventing the impact on power generation efficiency due to prolonged wind turbine downtime.

[0016] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall structure of the frequency conversion electromagnetic braking unit according to an embodiment of the present invention; Figure 2 This is an assembly diagram of the housing, annular armature, brake disc, and bushing according to an embodiment of the present invention. Figure 3 This is an assembly diagram of the housing, annular armature, and brake disc according to an embodiment of the present invention. Figure 4 This is a cross-sectional view of the housing according to an embodiment of the present invention; Figure 5 This is an exploded view of the assembly of the frequency conversion electromagnetic braking unit according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the brake disc and brake tooth disc according to an embodiment of the present invention; Figure 7 This is a front view of the variable frequency electromagnetic braking unit according to an embodiment of the present invention; Figure 8 This is a first-view view of the push-limiting component according to an embodiment of the present invention; Figure 9 This is a second-view view of the push-limiting component according to an embodiment of the present invention.

[0019] In the diagram: 1. Shell; 11. Recessed square groove; 12. Radial sliding groove; 2. Electromagnetic coil; 3. Brake spring; 4. Bushing; 41. Annular groove; 5. Conversion braking mechanism; 51. Ring armature; 511. Sliding hole; 52. Brake disc; 53. Brake toothed disc; 54. Connecting piece; 55. Friction disc; 56. Sleeve; 57. Ring cam; 58. External tooth; 59. Internal tooth; 6. Push limit assembly; 61. Inclined push block; 62. Limiting insert block; 63. Push screw; 64. Moving block; 65. T-slot; 66. T-block; 67. Push rod; 68. Support ring. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be understood that the terms "opening", "upper", "lower", "thickness", "top", "middle", "length", "inner", "around", etc., which indicate orientation or positional relationship, are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the components or elements referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this invention.

[0022] Please see Figures 1-9 As shown, the present invention is a variable frequency and variable force electromagnetic brake for wind turbine generators, including a variable frequency electromagnetic braking unit, an operating condition detection unit, and a central control unit. The variable frequency electromagnetic braking unit includes a housing 1, an electromagnetic coil 2 mounted on the housing 1, a braking spring 3 mounted inside the housing 1 and offset from the electromagnetic coil 2, and a switching braking mechanism 5 mounted on the top surface of the housing 1 and in contact with the braking spring 3; a bushing 4 is mounted on the switching braking mechanism 5, and a motor shaft is mounted inside the bushing 4. The operating condition detection unit includes a speed sensor, a load sensor, and a wind speed sensor. The speed sensor is installed on the main shaft of the wind turbine to detect the real-time speed of the main shaft. The load sensor is installed at the output end of the generator to detect the real-time load current and power of the generator. The wind speed sensor is installed on the top of the nacelle of the wind turbine to detect the real-time wind speed of the external environment. The operating condition detection unit converts the collected speed, load, and wind speed operating parameters into electrical signals and transmits them to the central control unit in real time. The central control unit adopts an embedded microprocessor, with ARM or DSP series chips as the core control chip, and has built-in operating condition analysis algorithms and braking strategy database. The central control unit receives the operating condition parameter electrical signals transmitted by the operating condition detection unit, analyzes and processes the parameters through the operating condition analysis algorithm, and determines the current operating status of the wind turbine, such as normal operation, need to decelerate and stop, emergency braking, etc. In combination with the preset braking logic in the braking strategy database, such as the matching relationship between the optimal current frequency, current intensity and braking torque under different operating conditions, the corresponding frequency control signal is generated and sent to the frequency converter controller of the frequency conversion electromagnetic braking unit. Furthermore, both the electromagnetic coil 2 and the braking spring 3 are installed by embedding, and the electromagnetic coil 2 adopts a multi-winding structure; while in the illustrated embodiment, the three braking springs 3 are evenly arranged on the housing 1 in a circumferential array. In a preferred embodiment of this solution, when the operating condition detection unit detects the operating status parameters of the wind turbine and transmits them to the central control unit, the central control unit generates a corresponding frequency control signal and sends it to the frequency converter, causing the multi-winding electromagnetic coil 2 installed in the housing 1 to be in an energized or de-energized state. The two states of the electromagnetic coil 2 will cause the motor shaft installed in the bushing 4 to be in a braking / rotating state. The process of achieving the braking / rotating state of the motor shaft is as follows: When an emergency braking is required on the motor shaft installed in the bushing 4, the frequency converter will operate according to the control signal received from the central control unit, so that the electromagnetic coil 2 located in the housing 1 is de-energized. At this time, some parts of the switching braking mechanism 5 will release the compression of the brake spring 3, so that the elastic thrust generated by at least three brake springs 3 will act on some parts of the switching braking mechanism 5, so that the bushing 4, which is located in the housing 1 and coaxially installed, is stopped from rotating, thus facilitating the emergency braking of the motor shaft installed in the bushing 4. When the motor shaft needs to be in the brake release state (the motor shaft is in the normal rotation state), the frequency converter will work according to the control signal received from the central control unit, so that the electromagnetic coil 2 located in the housing 1 is energized, so that the electromagnetic coil 2 generates a magnetic field, and some parts of the switching braking mechanism 5 are compressed by the electromagnetic force, thereby changing the braking force. It should be noted that, since the electromagnetic coil 2 adopts a multi-winding structure, it can generate electromagnetic attraction of different intensities under current excitation at different frequencies. Furthermore, a frequency converter is connected in series in the power supply circuit of the electromagnetic coil 2. Therefore, the frequency converter can adjust the current frequency and current intensity input to the electromagnetic coil 2 according to the frequency control signal sent by the central control unit, thereby changing the magnitude of the electromagnetic attraction generated by the electromagnetic coil 2 and thus achieving precise adjustment of the braking torque. Furthermore, when the electromagnetic attraction generated by the electromagnetic coil 2 is at its maximum, at least three brake springs 3 can be fully compressed by the switching brake mechanism 5, so that the switching brake mechanism 5 can completely disengage from the brake on the bushing 4, thereby releasing the brake on the motor shaft and allowing the motor shaft to rotate. This solution integrates a variable frequency electromagnetic braking unit, a working condition detection unit, and a central control unit. The working condition detection unit can collect real-time parameters such as generator speed, load, and wind speed. The central control unit can generate corresponding frequency control signals based on the collected data. The variable frequency controller can adjust the frequency and intensity of the current input to the electromagnetic coil 2, thereby changing the magnitude of the electromagnetic attraction generated by the electromagnetic coil 2 and achieving precise adjustment of the braking torque. This solves the problem that traditional electromagnetic brakes are difficult to achieve smooth braking transition and are prone to generating large inrush currents and braking shocks. It should be added that the central control unit also has a fault diagnosis function, which can monitor the operating status of each unit in real time. When a fault is detected, such as abnormal data of the working condition detection unit or abnormal current of the frequency conversion electromagnetic braking unit, a fault alarm signal is immediately issued and an emergency braking plan is activated, such as switching to the standby braking mode or forcibly powering off and resetting.

[0023] See Figures 1 to 7 As shown, it can be clearly seen that the structure or related components of the conversion braking mechanism 5 include an annular armature 51 mounted on the top surface of the housing 1, a brake disc 52 placed on the upper surface of the annular armature 51, a brake gear disc 53 mounted on the brake disc 52 and cooperating with the bushing 4, and a friction disc 55 connected to the housing 1 by at least three circumferentially evenly distributed connecting members 54; the brake gear disc 53 and the brake disc 52 are exemplary to adopt an integral molding design; it is also conceivable that the upper and lower brake discs 52 are assembled onto the upper and lower surfaces of the brake gear disc 53. Furthermore, the connector 54 adopts a screw structure, and a sleeve 56 is sleeved on the connector 54 located between the friction disk 55 and the housing 1, and the two ends of the sleeve 56 abut against the surfaces of the housing 1 and the friction disk 55 to limit the distance between the friction disk 55 and the housing 1. The sleeve 56 and the sliding hole 511 opened on the annular armature 51 slide in each other, and the axial length of the sleeve 56 is the same as the sum of the thickness of the brake disc 52, the brake tooth disc 53 and the annular armature 51 and the distance of the brake air gap A formed between the annular armature 51 and the housing 1. As a preferred embodiment of this solution, the process of assembling the annular armature 51, brake disc 52, brake gear disc 53, and friction disc 55 onto the housing 1 via the connector 54 is as follows: First, the electromagnetic coil 2 needs to be fixedly installed in the annular groove 41 opened downward on the upper surface of the housing 1, and the wire of the electromagnetic coil 2 extends out of the housing 1. At least three brake springs 3 are also fixedly installed in the spring mounting holes opened downward on the upper surface of the housing 1, and the top of the brake springs 3 needs to extend out of the spring mounting holes. Then, the annular armature 51 is placed on the upper surface of the housing 1, so that the lower surface of the annular armature 51 contacts the brake spring 3. Then, the assembled brake disc 53 and brake disc 52 are placed on the upper surface of the annular armature 51, and the brake disc 52 contacts the annular armature 51. At this time, at least three sleeves 56 are inserted into the sliding hole 511 of the annular armature 51, and the sleeves 56 will be aligned with the threaded holes opened on the housing 1 for connection with the screw connector 54. The bushing 4 is simultaneously installed with the brake disc 53 at the center hole of the housing 1. Then place the friction disc 55 onto the brake disc 52 on the upper surface of the brake gear disc 53. At this time, it is important to note that the annular armature 51, the brake gear disc 53, and the friction disc 55 are coaxial with the center hole of the housing 1. Then insert the screws of the three screws into the through holes opened on the friction disc 55 and the sleeve 56 into the threaded holes opened on the housing 1, so as to facilitate the assembly of the conversion brake mechanism 5 onto the housing 1. It should be further explained that when the annular armature 51 is first placed on the brake spring 3, the brake spring 3 can be in a freely extended state. Therefore, when the sleeve 56 is placed on the housing 1, the upper opening of the sleeve 56 will be lower than the upper surface of the brake disc 52. Then, the friction disc 55 is placed on the upper brake disc 52, and the through hole of the friction disc 55 is aligned with the sleeve 56. At this time, the screw head is turned synchronously, so that the friction disc 55 will press down on the annular armature 51 through the upper and lower brake discs 52, so that the brake spring 3 will be continuously compressed. When the lower surface of the friction disc 55 abuts against the upper end of the sleeve 56, the sleeve 56 will provide gravity support and axial height limit for the friction disc 55, so that the friction disc 55 will only contact the upper brake disc 52. At this time, a brake air gap A will be formed between the lower surface of the annular armature 51 and the upper surface of the housing 1. The working principle of electromagnetic braking of bushing 4 by de-energizing or de-energizing electromagnetic coil 2 is as follows: When the power is cut off, the brake disc 53 and brake disc 52 meshing on the bushing 4 will be pressed against the friction disc 55 by the brake spring 3 through the annular armature 51. The surfaces of the upper and lower brake discs 52 of the brake disc 53 form two friction surfaces with the friction disc 55 and the annular armature 51 respectively. The friction force on the friction surface generates a braking torque, which will brake the motor shaft installed through the bushing 4. At this time, a brake air gap A will be formed between the lower surface of the annular armature 51 and the upper surface of the housing 1. When the electromagnetic coil 2 is energized through the extended wire, the electromagnetic coil 2 will generate a magnetic field. Under the action of electromagnetic force, the ring armature 51 will move toward the surface of the housing 1 and compress the brake spring 3 until the ring armature 51 is completely in contact with the housing 1. At this time, the brake air gap A will disappear and the brake disc 52 will be released. At this time, the brake toothed disc 53 will release the brake on the bushing 4, and the motor shaft can rotate. It is also conceivable that, in the implementation of this invention, given that the thickness of the annular armature 51, the brake disc 52, and the brake toothed disc 53, as well as the length of the brake spring 3, are fixed, the axial dimension of the brake air gap A is determined by the height of the sleeve 56. That is, if it is necessary to increase the frictional force between the surface of the brake disc 52 and the two friction surfaces formed between the friction disc 55 and the annular armature 51, so as to improve the electromagnetic braking force of the motor shaft, then it is only necessary to use a shorter sleeve 56 to reduce the axial dimension of the brake air gap A (increase the compression deformation of the brake spring 3). Therefore, the clever installation of the conversion braking mechanism 5 on the housing 1 in this solution has the following beneficial effects: First, the electromagnetic brake in this solution is a dry friction electromagnetic brake with spring pressure. It relies on the friction force generated by the pressure of the brake spring 3 to generate braking torque. Therefore, the brake can play a braking role when it is not energized or when the circuit fails. When it is necessary to release the brake, the electromagnetic coil 2 is energized, and the electromagnetic force cancels the spring force of the brake spring 3, thereby releasing the brake. Secondly, through the cooperation of at least three sleeves 56 evenly arranged around the circumference and screws, the sleeves 56 can not only provide axial height limit support for the friction disc 55, but also, since the sleeves 56 are slidably engaged with the sliding hole 511, they can also limit the rotation of the annular armature 51 without affecting the axial movement of the annular armature 51. When the bushing 4 is disengaged from the brake, the annular armature 51 rotates. Thirdly, even if one of the friction surfaces in contact with the friction disc 55, the annular armature 51, and the brake disc 52 wears down, affecting the braking force of the brake spring 3 on the brake disc 52 through the annular armature 51, simply replacing the sleeve 56 with a shorter axial height will reduce the size of the brake air gap A formed between the annular armature 51 and the housing 1, allowing for quick adjustment of the electromagnetic brake's braking effect on the motor shaft. This eliminates the need for frequent parts replacement, reducing maintenance costs and preventing the extended downtime of the wind turbine from affecting power generation efficiency.

[0024] See Figure 2 , Figure 3 , Figure 5 and Figure 6As shown, the outer ring surface of the bushing 4 is formed with an annular cam 57, and the annular cam 57 extends to the upper surface of the annular armature 51. The outer ring surface of the annular cam 57 is formed with external teeth 58, and the inner ring surface of the brake disc 53 is formed with internal teeth 59 that mesh with the external teeth 58. The length of the external teeth 58 is greater than the length of the internal teeth 59. As a preferred embodiment of this solution, the bushing 4 can contact the annular armature 51 through the annular cam 57, so that the annular armature 51 can provide initial support for the bushing 4 and prevent the bushing 4 from being excessively inserted into the central hole of the housing 1. The meshing of the external teeth 58 and the internal teeth 59 on the brake disc 53 allows the annular armature 51 to brake the brake disc 52 via the brake spring 3, and the brake disc 53 to axially brake the bushing 4 via the meshing of the internal teeth 59 and the external teeth 58, thereby facilitating the braking of the motor shaft. The length of the external tooth 58 is greater than the length of the internal tooth 59, so that when the annular armature 51 drives the brake disc 53 to rise or fall a short distance through the brake disc 52, the bushing 4 can be connected to the brake disc 53 for transmission, thereby enabling precise braking of the motor shaft mounted on the bushing 4.

[0025] See Figure 5 , Figure 7 , Figure 8 and Figure 9 As shown, the bottom end of the bushing 4 extends into the central hole of the housing 1, and the outer ring surface of the bushing 4 is provided with an annular groove 41; The inner wall of the central hole of the housing 1 is provided with a circumferential array of four recessed square grooves 11, and each recessed square groove 11 is provided with a push-limiting component 6 for axially limiting the bushing 4. Furthermore, the inner wall of the recessed square groove 11 is inclined, and the pushing and limiting component 6 includes an inclined push block 61 installed in the recessed square groove 11 and having a thickness less than the groove width of the recessed square groove 11, a limiting insert block 62 installed in the recessed square groove 11 and in contact with the vertical surface of the inclined push block 61, a push screw 63 threaded to the bottom of the recessed square groove 11, and a pushing and misaligning component connecting the push screw 63 and the inclined push block 61. The inclined surface of the inclined push block 61 fits against the inclined surface of the recessed square groove 11. A threaded hole for the push screw 63 to be connected is provided between the bottom of the housing 1 and the bottom of the recessed square groove 11. A radial sliding groove 12 is provided radially at the bottom of the recessed square groove 11. A moving block 64 connected to the limiting insert block 62 is movably installed in the radial sliding groove 12. A return spring is connected between the moving block 64 and the groove wall of the radial sliding groove 12. As a preferred embodiment of this solution, in order to prevent the assembled bushing 4 from undergoing axial displacement within the housing 1, which would cause the external teeth 58 and internal teeth 59 formed on the outer ring surface of the annular cam 57 to fail to mesh accurately, thereby affecting the precise braking effect of the electromagnetic brake on the motor shaft; When the bushing 4 is inserted into the central hole of the housing 1, and the external teeth 58 and internal teeth 59 mesh, the annular groove 41 on the outer surface of the bushing 4 aligns with the opening of the recessed square groove 11, and the outer surface of the bushing 4 is not in contact with the wall of the central hole. The push screw 63 is preferably an internal hexagon screw, and the bottom of the housing 1 has a countersunk hole corresponding to the threaded hole. When the screw of the push screw 63 is continuously twisted into the threaded hole, the top of the screw will contact the push-off misalignment component, and the push-off misalignment component will push the inclined surface of the inclined push block 61 to move upward along the inclined surface of the recessed square groove 11. At this time, the inclined push block 61 moving upward along the inclined surface will generate radial movement in the recessed square groove 11, and thus the inclined push block 61 will move radially. When the sleeve 4 moves, a portion of the limiting block 62 extends out of the recessed square groove 11, and the extended portion of the limiting block 62 inserts into the aligned annular groove 41. This allows the limiting block 62 located in the recessed square groove 11 and the annular groove 41 to axially limit the sleeve 4. This not only prevents the sleeve 4 from detaching from the center hole of the housing 1 when the motor shaft is installed or removed, but also prevents the annular armature 51 from axially moving under the action of the brake spring 3 or the electromagnetic coil 2. Because the annular convex disk 57 formed on the outer ring surface of the sleeve 4 contacts the annular armature 51, the axial limiting of the sleeve 4 by the inserted limiting block 62 at this time will not cause the sleeve 4 to move axially at the same time as the annular armature 51. When part of the limiting block 62 extends out of the recessed square groove 11, the moving block 64 at the bottom of the limiting block 62 will slide in the radial groove 12, and the reset spring in the radial groove 12 will be compressed. When the annular armature 51 disengages from the brake disc 52, causing the bushing 4 and the mounted motor shaft to rotate, since at least four limiting blocks 62 are inserted into the annular groove 41 on the outer ring surface of the bushing 4, the inserted limiting blocks 62 do not affect the axial limiting movement of the bushing 4, nor do they interfere with the normal rotation of the bushing 4, thus enabling the motor shaft to actually operate. When the bushing 4 needs to be disassembled, the push screw 63 needs to be removed from the bottom of the housing 1 in sequence. When the top of the push screw 63 is disengaged from the push of the displacement component, the inclined push block 61 will move downward along the inclined surface of the recessed square groove 11. At the same time, the inclined push block 61 will also move radially in the opposite direction, so that it is disengaged from the push of the limit plug 62. Under the elastic reset of the return spring, the limit plug 62 moves into the recessed square groove 11, thereby causing part of the limit plug 62 to disengage from the annular groove 41, which makes it easier to disassemble and replace the bushing 4. The push screw 63 does not need to be completely removed from the threaded hole. It is only necessary to disengage the push screw 63 from the push of the displacement component.

[0026] See Figure 4 , Figure 7 , Figure 8 and Figure 9 As shown, the pushing and misaligning assembly includes a T-slot 65 radially opened on the bottom surface of the inclined push block 61, a T-block 66 movably installed in the T-slot 65, a push rod 67 connected to the bottom of the T-block 66, and a support ring 68 sleeved on the outside of the push rod 67. The bottom of the recessed square groove 11 is provided with a countersunk hole at the point where it aligns with the threaded hole. The push rod 67 is inserted into the countersunk hole, and the support ring 68 is connected to the bottom of the countersunk hole by a spring. In a preferred embodiment of this solution, when the top of the push screw 63 enters the countersunk hole and contacts the bottom of the push rod 67, the continued rotation of the push screw 63 will cause the push rod 67 to move upward into the recessed square groove 11. The upward movement of the push rod 67 will then drive the inclined push block 61 to move upward within the recessed square groove 11 via the T-block 66. Because the inclined surface of the inclined push block 61 engages with the inclined cut surface of the recessed square groove 11, this will cause the inclined push block 61 to generate… Radial movement (the inclined push block 61 moves toward the groove opening of the recessed square groove 11), and when the inclined push block 61 moves radially, the T-shaped block 66 will slide relative to the T-shaped groove 65, so that when the push rod 67 pushes the inclined push block 61 upward, the inclined push block 61 will not move radially when the push rod 67 pushes the inclined push block 61 vertically because the push rod 67 is fixedly connected to the inclined push block 61, which will affect the accurate insertion of the limiting plug 62 into the annular groove 41; When the push rod 67 moves upward in the countersunk hole and threaded hole, the spring connected to the bottom of the support ring 68 will be stretched. When the push screw 63 disengages from the push rod 67, the spring connected to the bottom of the support ring 68 will pull the support ring 68 into the countersunk hole, so that the push rod 67 drives the inclined push block 61 to slide downward in the recessed square groove 11 through the T-block 66. This facilitates the release of the limit plug 62 from the annular groove 41 under the elastic reset push of the reset spring connected to its bottom moving block 64, so that the bushing 4 or the external tooth 58 that has been worn for a long time can be removed and replaced from the housing 1. Since the descent of the inclined push block 61 within the recessed square groove 11 is driven by the push rod 67, and the radial movement of the inclined push block 61 is pushed by the limiting insert block 62 moving into the recessed square groove 11, the inclined push block 61 can accurately fit with the inclined surface of the recessed square groove 11 when it descends within the recessed square groove 11. This makes it easier for the inclined push block 61 to rise again along the inclined surface of the recessed square groove 11, and accurately push the limiting insert block 62 out of the recessed square groove 11 to axially limit the bushing 4.

[0027] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A variable frequency electromagnetic brake for a wind turbine generator, comprising a variable frequency electromagnetic braking unit, a working condition detection unit, and a central control unit, characterized in that: The variable frequency electromagnetic braking unit includes a housing, an electromagnetic coil mounted on the housing, a braking spring mounted inside the housing and offset from the electromagnetic coil, and a switching braking mechanism mounted on the top surface of the housing and in contact with the braking spring; a bushing is mounted on the switching braking mechanism, and a motor shaft is mounted inside the bushing. The operating condition detection unit is used to collect the operating condition parameters of the wind turbine in real time. The central control unit is used to receive electrical signals of operating parameters transmitted by the operating condition detection unit, analyze and process the parameters through the operating condition analysis algorithm, and determine the current operating status of the wind turbine. A frequency converter is connected in series in the power supply circuit of the electromagnetic coil, and the frequency converter is electrically connected to the central control unit.

2. The variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 1, characterized in that, The switching braking mechanism includes an annular armature mounted on the top surface of the housing, a brake disc placed on the upper surface of the annular armature, a brake gear disc mounted on the brake disc and cooperating with a bushing, and a friction disc connected to the housing via a connecting member. Both the electromagnetic coil and the braking spring are installed by embedding, and the electromagnetic coil adopts a multi-winding structure.

3. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 2, characterized in that, The connector adopts a screw structure, and a sleeve is fitted on the connector located between the friction disc and the housing. The two ends of the sleeve abut against the surfaces of the housing and the friction disc to limit the distance between the friction disc and the housing. The sleeve and the sliding hole on the annular armature slide together, and the axial length of the sleeve is the same as the sum of the thickness of the brake disc, the brake tooth disc and the annular armature and the distance of the brake air gap A formed between the annular armature and the housing.

4. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 2, characterized in that, The outer ring surface of the bushing is formed with an annular cam, which extends to the upper surface of the annular armature. The outer ring surface of the annular cam is formed with external teeth, and the inner ring surface of the brake disc is formed with internal teeth that mesh with the external teeth. The length of the external teeth is greater than the length of the internal teeth.

5. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 2, characterized in that, The bottom end of the bushing extends into the central hole of the housing, and an annular groove is provided on the outer ring surface of the bushing; The inner wall of the central hole of the housing is provided with at least one recessed square groove, and each recessed square groove is provided with a push-limiting component for axially limiting the bushing.

6. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 5, characterized in that, The inner wall of the recessed square groove is inclined. The pushing and limiting component includes an inclined push block installed in the recessed square groove, a limiting plug installed in the recessed square groove and in contact with the vertical surface of the inclined push block, a top push screw threaded to the bottom of the recessed square groove, and a pushing and misaligning component connecting the top push screw and the inclined push block. A threaded hole for connecting a push screw is provided between the bottom of the housing and the bottom of the recessed square groove; a radial sliding groove is provided in the bottom of the recessed square groove, and a movable block connected to a limiting block is movably installed in the radial sliding groove; a return spring is connected between the movable block and the groove wall of the radial sliding groove.

7. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 6, characterized in that, The pushing and misaligning assembly includes a T-slot radially formed on the bottom surface of the inclined push block, a T-block movably installed in the T-slot, a push rod connected to the bottom of the T-block, and a support ring sleeved on the outside of the push rod. A countersunk hole is provided at the bottom of the recessed square groove where it aligns with the threaded hole. The push rod is inserted into the countersunk hole, and the support ring is connected to the bottom of the countersunk hole by a spring.

8. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 1, characterized in that, The operating condition detection unit includes a speed sensor, a load sensor, and a wind speed sensor. The speed sensor is installed on the main shaft of the wind turbine to detect the real-time speed of the main shaft. The load sensor is installed at the output end of the generator to detect the real-time load current and power of the generator. The wind speed sensor is installed on the top of the nacelle of the wind turbine to detect the real-time wind speed of the external environment. The operating condition detection unit converts the collected speed, load, and wind speed operating parameters into electrical signals and transmits them to the central control unit in real time.

9. A variable frequency and variable force electromagnetic brake for a wind turbine generator according to claim 1, characterized in that, The central control unit uses an embedded microprocessor as the core control chip and has built-in operating condition analysis algorithms and braking strategy database.

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