Magnetorheological wind driven generator based on electromagnet clutch

Abstract

The invention discloses a magneto-rheological wind driven generator of an electromagnet clutch, and belongs to the technical field of wind driven generators. The device is mainly composed of an electromagnet clutch, a generator set and a magneto-rheological brake. The fan turbine (16) drives the driving shaft (14) to rotate under the action of wind power, and according to the rotating speed of the driven shaft (13), attractive force or repulsive force is generated on the first-stage electromagnet (2) and the second-stage electromagnet (2) by controlling current, so that the driving shaft and the driven shaft are actively controlled to be combined or separated. The driven shaft drives magnetic flux of the rotor magnet (3) and the stator coil (10) to generate electric energy. The shaft coupling disc (9) is braked by controlling the magnet exciting coil (4) and the magnetorheological fluid (5). According to the invention, electric energy can be generated at a low rotating speed of a low wind speed, and meanwhile, when a braking limit of a magneto-rheological brake is exceeded at an ultrahigh wind speed, the driving shaft and the driven shaft are separated by controlling the electromagnet, and active overload protection is carried out on the generator.

Description

Technical Field

[0001] The invention relates to the technical field of magnetorheological wind generators, and in particular to the principle and design method of a magnetorheological wind generator based on an electromagnet clutch, belonging to the technical field of wind generators. Background Art

[0002] Magnetorheological fluid is a special fluid whose rheological properties can be controlled and adjusted by an external magnetic field. It consists of micron-sized magnetic particles suspended in a colloidal solution or oil-based liquid. These magnetic particles are dispersed in the base liquid in an irregular manner in the absence of an external magnetic field, showing a fluidity similar to that of Newtonian liquid. When an external magnetic field acts on the magnetorheological fluid, this smart material can quickly change from liquid to semi-solid in milliseconds, realizing a reversible phase change process. Magnetorheological fluid has the characteristics of fast response and controllability. Due to its characteristics, brakes designed based on magnetorheological fluid have a simple structure, reduce friction and wear, and can achieve overload protection. Compared with traditional brakes, magnetorheological brakes can provide modulated braking force. By adjusting the strength of the magnetic field, the output of the brake can be flexibly controlled to adapt to different working requirements.

[0003] A wind turbine is a device that can convert the kinetic energy of wind into electrical energy. During its operation, it is widely affected by the external wind speed. Studies have found that the speed of a wind turbine is linearly related to the wind speed. When the wind speed reaches 400m / s, the speed of the turbine generator may exceed 20,000r / min, which may cause the key components of the wind turbine, such as bearings and rotors, to undergo huge wear in a short period of time and are prone to failure. At the same time, the output voltage of the generator is proportional to the speed. In a high-speed environment, it is easy to cause the electronic components in the electronic circuit of the wind turbine to be broken down or burned. Therefore, in practical applications, the speed of the wind turbine must be effectively controlled to ensure that it does not exceed the specified value. This protection measure helps to protect the stable operation of the wind turbine and extend its service life.

[0004] There are currently three main methods for controlling the speed of wind turbines: one is to design a reasonable internal flow field based on aerodynamic theory to reduce the driving torque of the turbine; the second is to limit the increase in turbine speed through mechanical friction or devices; the third is to increase the resistance torque of the rotor. The first method involves designing complex flow channels, so it is relatively difficult to achieve efficient speed control; the second method requires a larger speed control device; as for the third method, achieving the adjustment of rotor resistance may require a more complex design and control system, increasing the cost of manufacturing and maintenance.

[0005] After research and analysis, a new type of magnetorheological wind turbine based on an electromagnetic clutch is designed. Under low and high wind speeds, the magnetorheological brake can accurately and efficiently control the shaft speed. In harsh environments with higher wind speeds, the electromagnetic clutch can separate the turbine drive shaft from the generator driven shaft to achieve active overload protection for the wind turbine.

[0006] Through patent search, there are the following known technical solutions: Application number: CN201711095418.5, application date: 2017.11.09, public announcement date: 2018.02.23, the present invention discloses a novel wind turbine drive system and a control method thereof, wherein the drive system is arranged outside the rotating shaft connecting the wind turbine main shaft and the generator main shaft, and comprises a magnetic isolation box and a first permanent magnet, a second permanent magnet and a first electromagnet, a second electromagnet, a first electromagnet and a second electromagnet arranged in the magnetic isolation box, the first permanent magnet is arranged outside the rotating shaft, and is fixedly connected to the outer wall of the rotating shaft and can be Synchronous rotation; the magnetic field direction of the second permanent magnet is opposite to that of the first permanent magnet; after the first electromagnet and the second electromagnet are energized, the magnetism of the first electromagnet is opposite to that of the first permanent magnet, while the magnetism of the second electromagnet is the same as that of the first permanent magnet; by detecting the generator speed and the external wind speed, the second permanent magnet, the first electromagnet and the second electromagnet are respectively controlled accordingly to realize the operation of the generator at the rated speed, whether it is a breeze or a typhoon, storm and other conditions, the normal operation of the generator can be realized, the utilization rate of wind energy is effectively improved, the cost of electricity is reduced, and it has broad promotion significance and market value.

[0007] The above patent solves the technical problem of controlling the rated speed of a wind turbine generator under high wind speed. It uses the principle of the brushless motor stator driving the rotor to rotate, and uses an electromagnet as a stator to control the speed of the generator main shaft as the rotor. It cannot achieve precise control of the shaft speed for the time being. Since a large current needs to be passed through the electromagnet during the control process and it needs to be continuous, the cost is relatively high.

[0008] Through patent search, there are the following known technical solutions: Application number: CN202110541888.X, application date: 2021.05.18, public announcement date: 2022-07-15, the present invention discloses a magnetorheological cascade generator, which belongs to the field of wind power generation. It is mainly composed of three parts: a primary generator, a secondary generator, and a magnetorheological clutch. The turbine rotates under the action of wind power, driving the rotating shaft to rotate, the primary generator generates electrical energy output, and a control current is applied to the coil. The magnetorheological clutch starts to work, generating a damping torque on the rotating shaft, and the inner cylinder starts to rotate under the transmission torque at the same time, and the secondary generator generates electrical energy output. The patent of this invention can generate higher electrical energy output at the same speed, improve the energy conversion efficiency of the wind turbine generator; and generate a controllable damping torque through the magnetorheological fluid to accurately control the speed of the generator.

[0009] The above patent solves the problem that the wind turbine speed is too high, causing the generator parts to wear out and the circuit to be damaged, and the problem that the wind turbine power output is low after the speed is controlled. By cleverly utilizing the special material properties of magnetorheological fluid, a magnetorheological clutch is designed to achieve multi-level output of the generator while controlling the generator speed. And it also achieves precise control of the shaft speed. Since the speed control is completely dependent on the magnetorheological fluid, there is a lack of protection measures for higher speeds, and the main shaft and bearings may still be damaged at high wind speeds.

[0010] Through the above search, it is found that the above technical solutions do not affect the novelty of the present invention, and the mutual combination of the above patent documents does not destroy the creativity of the present invention. Summary of the invention

[0011] In view of the above problems, the present invention discloses a magnetorheological wind turbine based on an electromagnet clutch, and the technical problem to be solved is: the problem that the wind turbine speed is too high, causing the generator parts to wear and fail and the circuit to be damaged. An electromagnet clutch is designed by using an electromagnet, and combined with the special material properties of magnetorheological fluid, it can control the generator speed while protecting the shaft and rotor of the generator under ultra-high wind speeds. At the same time, the overall structure of the wind turbine has the following advantages: (1) small generator; (2) strong overload resistance; (3) precise speed control; (4) fast response speed; (5) high energy conversion efficiency; (6) simple and easy to understand working principle; (7) reliable structure, and can work in many environments; (8) mature manufacturing process.

[0012] The objective of the present invention is achieved through the following technical solutions:

[0013] The present invention discloses a magnetorheological wind turbine based on an electromagnet clutch, which includes an electromagnet clutch, a generator set, and a magnetorheological brake. The excitation coil generates a magnetic field by controlling the current. Due to the characteristics of the magnetorheological fluid itself, when the magnetic field passes through the magnetorheological fluid gap in the brake, the magnetorheological fluid produces a corresponding rheological effect. Under the rheological effect, the magnetorheological fluid solidifies, and its damping torque on the driven shaft is increased, thereby reducing the rotation speed of the shaft immersed in the magnetorheological fluid. When the driven shaft is lower than the rated speed, an attraction is generated between the two-stage electromagnets by passing the electromagnet clutch to control the current, and the gears of the driving shaft and the driven shaft are meshed, so that the driven shaft rotates with the driving shaft. When the wind speed is too high and the driven shaft speed is higher than the rated speed, the limit of the magnetorheological fluid deceleration is exceeded. By passing the electromagnetic clutch to control the current, a repulsive force is generated between the two-stage electromagnets, so that the drive shaft and the driven shaft gear are actively separated. When the driven shaft speed is lower than the rated speed, the electromagnetic clutch is passed to control the current to generate an attractive force between the two-stage electromagnets, so that the drive shaft and the driven shaft gears are meshed again, and the driven shaft rotates with the drive shaft again. This protects the driven shaft where the generator is located from overload.

[0014] Beneficial effects:

[0015] 1. The magnetorheological wind turbine material disclosed in the present invention is mainly iron and aluminum, which are abundant in source, huge in stock, and low in production cost. Meanwhile, the manufacturing process of the relevant structural main body used therein is mature, and it is an economically feasible solution.

[0016] 2. The magnetorheological wind turbine disclosed in the invention is different from the traditional wind turbine structure. It cleverly uses the magnetorheological clutch to achieve precise control of the wind turbine shaft speed, with high control accuracy and fast response speed.

[0017] 3. The magnetorheological wind turbine disclosed in the present invention adopts an electromagnetic clutch, which can protect the driven shaft of the generator under high wind speed and harsh working environment while controlling the speed, and has stronger adaptability to harsh working environment.

[0018] 4. Magnetorheological fluid produces rheological effect under the action of magnetic field, and the response speed is very fast, which is in milliseconds.

[0019] 5. The magnetorheological wind turbine disclosed in the present invention is different from the traditional wind turbine structure. It is small in size, light in weight, simple in structure and easy to disassemble and install. At the same time, each part is compact and has low processing difficulty, which is more suitable for miniaturization. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the overall structure of a wind turbine based on a micro magnetorheological actuator.

[0021] Among them: 1-deep groove ball bearing, 2-first and second level electromagnet, 3-rotor magnet, 4-excitation coil, 5-magnetorheological fluid, 6-main housing, 7-lower end cover, 8-deep groove ball bearing, 9-shaft coupling disc, 10-stator coil, 11-magnetic isolation material, 12-deep groove ball bearing, 13-driven shaft, 14-driving shaft, 15-upper end cover, 16-fan turbine DETAILED DESCRIPTION

[0022] In order to better illustrate the operation and design purpose of the present invention, the invention content is further described below with reference to the accompanying drawings and operating examples.

[0023] Embodiment 1:

[0024] A wind turbine generator based on a micro-magnetic rheological actuator in the first embodiment is shown in the figure, which mainly consists of three parts: a generator set, a magnetorheological brake, and primary and secondary electromagnets.

[0025] The fan turbine (16) rotates at high speed under the action of wind, driving the rotor magnet (3) to rotate, generating a change in magnetic flux between the rotor and the stator coil (10). According to Faraday's law of electromagnetic induction, the generator generates an induced electromotive force, completing the overall power output of the generator.

[0026] In the structure, the first and second electromagnets (2) generate a magnetic field by passing a control current. When the first and second electromagnets pass a current in the same direction, an attractive force is generated between the two magnets. The upper electromagnet is fixed to the drive shaft (14) through a deep groove ball bearing (1), and the lower electromagnet is fixed to the main housing (6). The drive shaft and the driven shaft (13) attract each other, so that the gears of the drive shaft and the driven shaft are meshed. When the first and second electromagnets pass a current in the opposite direction, a repulsive force is generated between the two magnets. The drive shaft and the driven shaft connected by the electromagnets repel each other, and the drive shaft bounces upward to the upper end cover, so that the gears of the drive shaft and the driven shaft are actively separated.

[0027] The excitation coil (4) generates a magnetic field by controlling the current. Due to the characteristics of the magnetorheological fluid (5), when the magnetic field passes through the magnetorheological fluid gap in the clutch, the magnetorheological fluid produces a corresponding rheological effect. Under the rheological effect, the magnetorheological fluid solidifies, and its damping torque on the driven shaft increases, thereby reducing the speed of the driven shaft (13) immersed in the magnetorheological fluid, and further reducing the speed of the drive shaft (14) connected to the driven shaft. When the driven shaft is lower than the rated speed, the two-stage electromagnets are attracted to each other by passing the electromagnetic clutch to control the current, and the driven shaft rotates with the drive shaft, and the Faraday electromagnetic effect occurs between the rotor magnet (3) and the stator coil (10) on the driven shaft, thereby generating electric energy output. When the wind speed is too high, the speed of the driven shaft driven by the turbine (16) and the driving shaft is higher than the rated speed, and exceeds the limit of the deceleration of the magnetorheological fluid, the electromagnetic clutch is passed to control the current so that a repulsive force is generated between the two-stage electromagnets, so that the driving shaft and the driven shaft are actively separated, and the overload protection of the driven shaft where the generator is located is realized under high wind speed. When the speed of the driven shaft is lower than the rated speed, the electromagnetic clutch is passed to control the current so that an attractive force is generated between the two-stage electromagnets, so that the gears of the driving shaft and the driven shaft are meshed again, and the driven shaft rotates with the driving shaft again, and the magnetorheological wind turbine generator resumes operation to generate electricity.

[0028] Finally, it should be noted that the specific description described above further illustrates the purpose, technical solutions and beneficial effects of the invention in detail, with the aim of helping to further understand the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A magnetorheological wind turbine based on an electromagnet clutch, characterized in that: The generator comprises: an electromagnetic clutch, a generator set, and a magnetorheological brake; the electromagnetic clutch comprises a turbine (16), a drive shaft (14), a deep groove ball bearing (1), an upper end cover (15), a two-stage electromagnet (2), and a driven shaft (13); meshing teeth are provided on the surfaces of the drive shaft (14) and the driven shaft (13); the structure can be engaged or separated by the attraction or repulsion of the electromagnet; the generator set comprises a pair of rotor magnets (3), a stator coil (10), and a deep groove ball bearing is provided between the driven shaft (13) and the housing (6); in the structure, the magnetic flux between the rotor magnet (3) and the stator coil (10) is driven by the action of the slave to generate a change in magnetic flux to output electric energy; the magnetorheological brake comprises an excitation coil (4), a magnetorheological fluid (5), and a shaft-connected disc (9). The magnetorheological fluid is filled between the shaft-connected discs; in the structure, a magnetic field is generated by the excitation coil (4) to solidify the magnetorheological fluid and increase the damping torque.

2. A magnetorheological wind turbine based on an electromagnet clutch according to claim 1, characterized in that: The upper electromagnet in the electromagnetic clutch is fixed to the drive shaft (14), the drive shaft (14) and the upper electromagnet are connected via a deep groove ball bearing (1), the deep groove ball bearing and the drive shaft (14) are fixed via an interference fit, the lower magnet in the electromagnetic clutch is fixed to the housing (6), a gap exists between the lower magnet and the driven shaft (13), and a non-contact form is adopted.

3. A magnetorheological wind turbine based on an electromagnet clutch according to claim 1, characterized in that: A meshing gear is provided between the driving shaft (14) and the driven shaft (13), and a sufficient gap is left between the upper end cover (15) and the upper magnet in the electromagnet clutch to separate the gears of the driving shaft (14) and the driven shaft (13).

4. A magnetorheological wind turbine based on an electromagnet clutch according to claim 1, characterized in that: An electromagnetic clutch is used. When the wind speed is below the rated wind speed, the two-stage electromagnets (2) attract each other, the turbine (16) drives the driving shaft (14) and the driven shaft (13) to rotate, and the Faraday electromagnetic effect occurs between the rotor magnet (3) on the driven shaft and the stator coil (10), thereby generating electric energy output. When the wind speed is too high, the rotation speed of the driving shaft (14) and the driven shaft (13) is higher than the rated rotation speed, and exceeds the deceleration limit of the magnetorheological fluid, a repulsive force is generated between the two-stage electromagnets (2) by passing a control current through the electromagnetic clutch, so that the driving shaft (14) and the driven shaft (13) are actively separated, thereby achieving safe overload protection for the generator under high wind speed conditions.

Images