Magnetic suspension bearing supporting system of vertical axis wind turbine
By using upper radial hybrid magnetic bearings and lower radial-axial hybrid magnetic bearings in wind turbines, combining ball bearings and displacement sensors, the five degrees of freedom of the wind turbine shaft are realized, and the traditional wind turbine power generation is solved The machine bearing wear and high cost problems of large volume and high cost of the magnetic levitation system improves wind energy utilization and system efficiency.
Patent Information
- Application Number
- CN202420756530.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-12
- Publication Date
- 2024-12-31
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The bearing systems of traditional wind turbines are prone to wear during long-term operation, resulting in increased maintenance costs, noise problems and reduced energy efficiency. In addition, existing magnetic levitation wind turbines have problems such as large number of power amplifiers, large volumes and high costs.
Design a magnetic levitation bearing support system for vertical axis wind turbines, using upper radial hybrid magnetic bearings and lower radial-axial hybrid magnetic bearings, both of which are six-pole hybrid magnetic bearings, which provide biased magnetic flux through permanent magnets, combined with balls Bearings and displacement sensors realize stable suspension of five degrees of freedom of the rotating shaft, simplifying the magnetic levitation support structure.
It significantly reduces mechanical friction and wear, reduces maintenance costs and starting wind speed, improves wind energy utilization and system efficiency, reduces system volume and production costs, and improves controlled accuracy.
Smart Images
Figure CN222276854U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of wind turbines, and in particular relates to a magnetic suspension bearing support system for a vertical axis wind turbine. Background Art
[0002] In response to the two major global issues of energy demand and environmental protection, wind power generation, as a clean and renewable energy solution, is becoming increasingly important. Wind power generation technology uses wind energy to convert into electrical energy, which not only helps reduce dependence on fossil fuels, but also significantly reduces greenhouse gas emissions.
[0003] Traditional wind turbines are mainly composed of core components such as blades, generators and towers, among which the performance of the bearing system is a key factor in determining the operating efficiency and reliability of the entire equipment. At present, the commonly used bearing systems are mainly based on rolling bearings or sliding bearings. However, these traditional bearings are prone to wear during long-term operation, resulting in increased maintenance costs, noise problems and reduced energy efficiency. In view of this, in recent years, magnetic bearing technology has received widespread attention due to its significant features such as no friction and wear, no need for lubrication, and long life. This technology uses magnetic force to suspend the bearing, greatly reducing the friction and wear caused by mechanical contact, which not only reduces the starting resistance torque of the wind turbine, but also reduces the wind speed required for starting, thereby improving the utilization efficiency of wind energy.
[0004] The existing related technical solutions include 1) Patent document with publication number CN215672544U, which proposes a wind turbine using magnetic bearings; 2) Patent document with publication number CN104234935B, which proposes a vertical axis magnetic levitation wind turbine. However, in the wind turbine using magnetic bearings proposed in 1), both the radial magnetic bearings and the axial magnetic bearings are driven and controlled by DC power amplifiers, which requires a high number of power amplifiers and has the disadvantages of large size, high power consumption, and high cost. In the vertical axis magnetic levitation wind turbine proposed in 2), the axial magnetic bearing is used as a separate unit, which increases the axial length of the system, resulting in a large system size and high cost, which is not conducive to production and promotion. Utility Model Content
[0005] In view of the deficiencies in the prior art, the utility model provides a vertical axis wind turbine magnetic suspension bearing support system, which simplifies the magnetic suspension support structure, reduces the loss of the magnetic bearing system, and ultimately improves the utilization rate of wind energy.
[0006] The utility model achieves the above technical objectives through the following technical means.
[0007] A vertical axis wind turbine magnetic bearing support system is provided, wherein magnetic bearings are arranged on the upper and lower sides of the generator to support the wind turbine main shaft, wherein the upper magnetic bearing is a radial hybrid magnetic bearing, and the lower magnetic bearing is a radial-axial hybrid magnetic bearing.
[0008] Furthermore, the upper magnetic bearing and the lower magnetic bearing are both six-pole hybrid magnetic bearings.
[0009] Furthermore, in the upper magnetic bearing: the stator is a double-piece structure, fixed on the fan body, each stator is wound with 6 groups of radial windings, and a permanent magnet is arranged between the two stators; the rotor is sleeved on the main shaft.
[0010] Furthermore, in the lower magnetic bearing, a radial air gap is formed between the stator and the rotor, and the working air gap is 1.5 to 3 mm.
[0011] Furthermore, the radial part of the lower magnetic bearing includes a lower radial rotor and a lower radial stator, and the axial part includes a lower axial rotor and a lower axial stator; wherein the lower radial stator and the lower axial stator are fixed on the fan body, and a permanent magnet is provided between the lower radial stator and the lower axial stator; the lower radial rotor and the lower axial rotor are sleeved on the main shaft.
[0012] Furthermore, in the lower magnetic bearing, the radial part is at the top and the axial part is at the bottom.
[0013] Furthermore, six groups of radial windings are wound on the lower radial stator, and an axial winding is wound inside the lower axial stator.
[0014] Furthermore, a radial air gap is formed between the lower radial rotor and the lower radial stator, and the working air gap is 1.5 to 3 mm; an axial air gap is formed between the lower axial rotor and the lower axial stator, and the working air gap is 1.5 to 3 mm.
[0015] Furthermore, two protective bearings are provided in the fuselage and are respectively connected to the upper and lower ends of the main shaft, and a radial air gap is left between the protective bearings and the main shaft. The protective bearings are ball bearings, and a baffle is provided on the outer side of the upper protective bearing.
[0016] Furthermore, a radial displacement sensor and an axial displacement sensor are provided in the fuselage for monitoring the spindle offset.
[0017] The beneficial effects of the utility model are:
[0018] (1) The utility model provides a magnetic suspension bearing support system for a vertical axis wind turbine. By adopting radial and axial magnetic bearings, radial two-degree-of-freedom suspension at the upper end of the rotating shaft and three-degree-of-freedom suspension at the lower end of the rotating shaft are respectively realized, thereby ensuring stable suspension of the rotating shaft in five degrees of freedom, eliminating mechanical friction and wear, thereby significantly reducing maintenance costs, and at the same time reducing the starting wind speed, improving the overall efficiency of the system, simplifying the magnetic suspension support structure, reducing the loss of the magnetic bearing system, and improving the utilization rate of wind energy.
[0019] (2) In the present invention, both magnetic bearings adopt a six-pole symmetrical structure, which reduces the coupling between radial magnetic circuits and improves the control accuracy of the system.
[0020] (3) The radial-axial hybrid magnetic bearing in the lower part of the utility model adopts a combined design, in which the radial magnetic bearing and the axial magnetic bearing are designed in the same structure. The bias flux of the radial magnetic bearing and the axial magnetic bearing are jointly provided by permanent magnets, which improves the maximum axial bearing capacity and reduces the axial length of the magnetic bearing, thereby reducing the system volume and the production cost.
[0021] (4) In the lower magnetic bearing, the radial and axial magnetic bearings are independently arranged on both sides of the permanent magnet, so that the radial magnetic circuit and the axial magnetic circuit are independent of each other, reducing the coupling between them, which is conducive to the precise control of the magnetic bearing. Compared with the traditional vertical axis wind turbine, the present invention has excellent performance in structural simplicity, cost-effectiveness, low starting wind speed and wind energy utilization efficiency, and therefore has great market potential. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 This is the overall structural diagram of the magnetic bearing support system of the vertical axis wind turbine of the utility model;
[0023] FIG2( a ) is an axial cross-sectional view of the upper radial hybrid magnetic bearing;
[0024] FIG2( b ) is an end view of the upper radial hybrid magnetic bearing;
[0025] FIG3( a ) is an axial cross-sectional view of the lower radial-axial hybrid magnetic bearing;
[0026] FIG3( b ) is an end view of the lower radial-axial hybrid magnetic bearing;
[0027] Figure 4 This is a control block diagram of the magnetic bearing support system of the utility model.
[0028] Reference numerals:
[0029] 1-blade; 2-hub; 3-upper end protection bearing; 4-upper magnetic bearing;
[0030] 41-upper bearing stator; 42-upper bearing rotor; 43-upper permanent magnet; 44-upper bearing winding;
[0031] 5-lower end protection bearing; 6-generator; 61-generator rotor; 62-generator stator;
[0032] 7-lower magnetic bearing; 71-lower radial winding; 72-lower radial rotor; 73-lower radial stator;
[0033] 74-lower permanent magnet; 75-lower axial stator; 76-lower axial winding; 77-lower axial rotor;
[0034] 8-main shaft; 9-baffle; 10-fuselage; 11-tower;
[0035] 12- radial sensor; 13- axial sensor. DETAILED DESCRIPTION
[0036] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.
[0037] like Figure 1 The vertical axis wind turbine equipped with the magnetic bearing support system of the utility model is shown. The wind turbine body 10 is erected on the tower 11, and an impeller is arranged on the top of the fuselage 10, including a plurality of blades 1. The blades 1 are arranged on the main shaft 8 of the wind turbine through the hub 2, and the main shaft 8 is driven to rotate by wind force. A generator 6 is arranged in the fuselage 10, and the main shaft 8 is inserted into the fuselage 10 from the top to drive the generator 6 to operate and generate electricity. The generator 6 includes a generator rotor 61 and a generator stator 62, wherein the generator stator 61 is fixed on the fuselage 10, and the generator rotor 61 is sleeved on the main shaft 8 and opposite to the generator stator 62.
[0038] Two sets of magnetic bearings are respectively provided at the upper and lower parts of the generator 6 to support the main shaft 8, namely the upper magnetic bearing 4 and the lower magnetic bearing 7. The upper magnetic bearing 4 is a radial hybrid magnetic bearing, and the lower magnetic bearing 7 is a radial-axial hybrid magnetic bearing.
[0039] As shown in Figures 2(a) and 2(b), the upper magnetic bearing 4 is a six-pole hybrid magnetic bearing, which is driven and controlled by a three-phase AC inverter. It can effectively reduce the coupling between radial magnetic circuits and reduce the nonlinear relationship between the suspension force and the control current; wherein the rotor and the stator are both stacked by silicon steel sheets, thereby reducing the influence of the eddy current effect. The upper magnetic bearing 4 includes an upper bearing stator 41 and an upper bearing rotor 42. The upper bearing stator 41 is a double-piece structure fixed to the fuselage 10; six groups of upper bearing windings 44 are wound on each stator; and an upper permanent magnet 43 is provided between the two stators. The upper bearing rotor 42 is sleeved on the main shaft 8 and radially opposite to the upper bearing stator 41. A radial air gap is formed between the upper bearing stator 41 and the upper bearing rotor 42, and the specific working air gap is 1.5 to 3 mm, preferably 1.5 mm.
[0040] In Figure 2(a) and Figure 2(b), the solid line is the bias flux magnetic circuit, and the dotted line is the control flux magnetic circuit; the bias flux is formed by the upper permanent magnet 43, and passes through the permanent magnet N pole, the left stator, the rotor, the right stator to the permanent magnet S pole in sequence to form a bias flux circuit; the control flux is generated by energizing the upper bearing winding 44, and flows through the stator, the air gap, and the rotor in sequence to form a circuit.
[0041] As shown in Figures 3(a) and 3(b), the lower magnetic bearing 7 is also a six-pole hybrid magnetic bearing, including radial and axial parts; the radial part includes a lower radial rotor 72 and a lower radial stator 73, and the axial part includes a lower axial rotor 77 and a lower axial stator 75. The lower radial stator 73 and the lower axial stator 75 are fixed on the fuselage 10, wherein the lower radial stator 73 is at the top and the lower axial stator 75 is at the bottom. A lower permanent magnet 74 is provided between the lower radial stator 73 and the lower axial stator 75 to provide bias flux and separate radial and axial fluxes. Six groups of lower radial windings 71 are wound on the lower radial stator 73. A lower axial winding 76 is wound inside the lower axial stator 75. The lower radial rotor 72 and the lower axial rotor 77 are both sleeved on the main shaft 8; the lower radial rotor 72 is opposite to the lower radial stator 73, and a radial air gap is formed between the two, and the specific working air gap is 1.5-3mm, preferably 1.5mm; the lower axial rotor 77 is opposite to the lower axial stator 75, and an axial air gap is formed between the two, and the specific working air gap is 1.5-3mm, preferably 2mm.
[0042] In Figures 2(a) and 2(b), the solid line is the radial bias flux, the dotted line is the radial control flux, and the dotted line is the axial control flux; the bias flux is formed by the lower permanent magnet 74, and passes through the permanent magnet N pole, the axial left stator, the axial rotor, the main shaft 8, the radial rotor, the radial stator, and the permanent magnet S pole in sequence to form a bias flux circuit; the control flux is generated by energizing the lower radial winding 71, and flows through the radial stator, the air gap, the radial rotor, and the radial stator in sequence to form a circuit; the axial control flux is generated by energizing the lower axial winding 76, and flows through the axial stator, the air gap, and the axial rotor in sequence to form a circuit.
[0043] The radial part of the lower magnetic bearing 7 is driven and controlled by a three-phase AC inverter, and the axial part is driven and controlled by a bipolar DC power amplifier. Even though the radial and axial bearings share some parts in structure, due to the high magnetic resistance of the permanent magnet ring, the magnetic circuits of the axial and radial bearings are independent of each other, and the influence between the magnetic circuits is small, thereby maximizing the use of magnetic materials and improving the performance of the overall magnetic circuit.
[0044] When in use, the radial two-degree-of-freedom suspension of the upper end of the fan main shaft 8 is achieved through the upper magnetic bearing 4, and the three-degree-of-freedom suspension of the lower end of the fan main shaft 8 is achieved through the lower magnetic bearing 7, thereby ensuring the stable suspension of the main shaft 8 in the overall five degrees of freedom and eliminating mechanical friction losses.
[0045] In addition, in order to improve reliability, an upper end protection bearing 3 and a lower end protection bearing 5 are respectively provided at the upper and lower ends of the fuselage 10, which are used to connect the upper and lower ends of the main shaft 8 in the fuselage 10, and a certain radial air gap is maintained between the two protection bearings and the main shaft 8. The two protection bearings are conventional ball bearings. A baffle 9 is provided on the outer side of the upper end protection bearing 3 to form an axial protection air gap.
[0046] In order to monitor the displacement of the main shaft 8, two displacement sensors are provided in the fuselage 10; they are divided into a radial sensor 12 and an axial displacement sensor 13, which are used to monitor the displacement of the main shaft 8 in the radial direction and the axial direction respectively.
[0047] like Figure 4The control block diagram for the above-mentioned magnetic suspension bearing support system is shown; wherein the upper magnetic bearing 4 and the lower magnetic bearing 7 are both controlled by a PID controller. The radial parts of the upper magnetic bearing 4 and the lower magnetic bearing 7 are both driven and controlled by a three-phase AC inverter; the axial part of the lower magnetic bearing 7 is controlled by a bipolar DC power amplifier. The rotor displacement of the above-mentioned support system is obtained based on a radial sensor 12 and an axial sensor 13, wherein the radial displacement sensor probe and the axial displacement sensor probe both use eddy current sensors. The radial part control principle of the upper magnetic bearing 4 is the same as that of the lower magnetic bearing 7; taking the upper magnetic bearing 4 as an example, when the radial magnetic bearing is subjected to an external force, the rotor deviates from the equilibrium position, and after the radial displacement sensor detects the rotor offset displacement, the displacement signal is fed back to the controller, and the controller calculates the radial displacement deviation, and converts its displacement into a current signal through a PID controller. After the output current signal is transformed by 2 / 3, the magnitude of the control current in the three-phase coil is changed by controlling the three-phase inverter switch device, thereby changing the control magnetic flux, and the rotor is returned to the equilibrium position by adjusting the generated magnetic attraction. As for the axial part of the lower magnetic bearing 7, taking the axial magnetic bearing being subjected to an external force moving to the right as an example, when the rotor deviates from the equilibrium position, the axial displacement sensor detects the rotor offset displacement and feeds back the displacement signal to the controller. The controller converts the displacement signal detected by the sensor into a control current iz. In order to make the rotor return to the equilibrium position, the control current in the control coil on one side is increased to i0+iz, and the control current in the control coil on the right side is reduced to i0-iz, thereby generating a magnetic field in the iron core, thereby generating an electromagnetic force to make the rotor return to the equilibrium position.
[0048] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0049] The present invention is not limited to the above-mentioned embodiments. Without departing from the essential content of the present invention, any obvious improvement, replacement or deformation that can be made by those skilled in the art shall fall within the protection scope of the present invention.
Claims
1. A vertical axis wind turbine magnetic bearing support system, characterized in that: Magnetic bearings are provided on the upper and lower sides of the generator (6) to support the fan main shaft (8), wherein the upper magnetic bearing (4) is a radial hybrid magnetic bearing and the lower magnetic bearing (7) is a radial-axial hybrid magnetic bearing; In the upper magnetic bearing (4), the stator is a double-piece structure fixed on the fan body (10), each stator is wound with 6 groups of radial windings, and a permanent magnet is arranged between the two stators; the rotor is sleeved on the main shaft (8); The radial part of the lower magnetic bearing (7) includes a lower radial rotor (72) and a lower radial stator (73), and the axial part includes a lower axial rotor (77) and a lower axial stator (75); wherein the lower radial stator (73) and the lower axial stator (75) are fixed on a fan body (10), and a permanent magnet is provided between the lower radial stator (73) and the lower axial stator (75); and the lower radial rotor (72) and the lower axial rotor (77) are sleeved on a main shaft (8).
2. The vertical axis wind turbine magnetic bearing support system according to claim 1 is characterized in that: The upper magnetic bearing (4) and the lower magnetic bearing (7) are both six-pole hybrid magnetic bearings.
3. The vertical axis wind turbine magnetic bearing support system according to claim 1 is characterized in that: In the lower magnetic bearing (7), a radial air gap is formed between the stator and the rotor, and the working air gap is 1.5 to 3 mm.
4. The vertical axis wind turbine magnetic bearing support system according to claim 1, characterized in that: In the lower magnetic bearing (7), the radial part is at the top and the axial part is at the bottom.
5. The vertical axis wind turbine magnetic bearing support system according to claim 1, characterized in that: Six groups of radial windings are wound on the lower radial stator (73), and an axial winding is wound inside the lower axial stator (75).
6. The vertical axis wind turbine magnetic bearing support system according to claim 1, characterized in that: A radial air gap is formed between the lower radial rotor (72) and the lower radial stator (73), and the working air gap is 1.5 to 3 mm; an axial air gap is formed between the lower axial rotor (77) and the lower axial stator (75), and the working air gap is 1.5 to 3 mm.
7. The vertical axis wind turbine magnetic bearing support system according to claim 1, characterized in that: Two protective bearings are arranged in the machine body (10) and are respectively connected to the upper and lower ends of the main shaft (8). A radial air gap is left between the protective bearings and the main shaft (8). The protective bearings are ball bearings, and a baffle (9) is arranged on the outer side of the upper protective bearing.
8. The vertical axis wind turbine magnetic bearing support system according to claim 1, characterized in that: A radial displacement sensor and an axial displacement sensor are arranged inside the body (10) and are used to monitor the deviation of the main shaft (8).