CN108448856B - High-speed generator adopting radial layered composite integral permanent magnet outer rotor - Google Patents

Abstract

A high-speed generator adopting radial layered composite integral permanent magnet outer rotor is characterized in that: the high-speed motor includes an outer rotor and a stator disposed within the outer rotor; the stator is arranged in the axial through hole of the outer rotor, and a gap is reserved between the stator and the outer rotor; the structure can effectively reduce the heat source in the motor rotor, and radically solves the problem of overheating of the high-speed motor rotor. Meanwhile, the structure ensures the uniformity, the integrity and the consistency of the motor rotor, and can mechanically solve the problem that the permanent magnet is broken due to larger tensile stress under the condition of high-speed rotation.

Description

A high-speed generator using a radially layered composite integral permanent magnet outer rotor

Technical field

The invention relates to a high-speed generator using a radially layered composite integral permanent magnet outer rotor. It is a problem in the field of motors.

Background technique

Due to the high power density and high speed of the high-speed permanent magnet synchronous generator, the motor volume is much smaller than the medium and low-speed motors with the same output power, so it can effectively save materials; the small size of the high-speed motor makes it have a smaller moment of inertia and a larger Fast dynamic response capability; and because the high-speed motor can be directly connected to the prime mover, the traditional mechanical transmission device is omitted, thereby improving the efficiency of the traditional system and reducing noise. In particular, permanent magnet generators have the advantages of high power density, simple structure, no excitation loss and high efficiency, and are particularly suitable for use as medium and small high-speed motors. With the process of industrial electrification, using high-speed motors to replace the original diesel engines as the power source has many significant advantages, such as improving energy efficiency, reducing environmental noise, etc. The research and application of high-speed permanent magnet generators are in line with energy conservation. The economic development needs of emission reduction have now become one of the research hotspots in the international electrotechnical field, and have broad development prospects in aviation, ships, hybrid vehicles, high-speed grinders, energy storage flywheels and distributed power generation systems.

Compared with ordinary motors, the design of high-speed permanent magnet generators is more difficult. The speed of high-speed motors can reach tens of thousands or even hundreds of thousands of revolutions per minute, and the peripheral speed can reach more than 200m/s. When the motor rotates at high speed, the stator core loses The friction between the air and the rotor surface will cause great losses to the motor. At the same time, for high-speed permanent magnet motors, the eddy current loss of the rotor permanent magnets is very large. However, it is difficult for the motor rotor to dissipate heat, which will cause the temperature of the motor rotor to rise. If the temperature rises too high, the permanent magnet will undergo irreversible demagnetization when the temperature is too high, causing serious harm to the motor. Therefore, reducing the loss of the motor rotor has become one of the core issues in the design of high-speed permanent magnet motors. For high-speed permanent magnet motors, the problem of rotor strength is more prominent, because the permanent magnets cannot withstand the tensile stress generated by high-speed rotation and protection measures must be taken for the permanent magnets. Compared with inner-rotor high-speed motors, outer-rotor motors have a larger diameter and must withstand greater centrifugal force during high-speed rotation. At the same time, the rotor directly cooperates with other structures and needs to withstand a certain pressure load, so higher requirements are placed on the strength of the rotor.

Contents of the invention

Purpose of the invention: The present invention proposes a high-speed generator using a radially layered composite integral permanent magnet outer rotor. Its purpose is to solve the problem of damage and rotor eddy currents caused by insufficient permanent magnet strength in high-speed rotation of previous high-speed permanent magnet motors. Large losses and difficult heat dissipation cause irreversible demagnetization of the permanent magnets, which seriously affects the reliability and operating life of the motor, thereby greatly improving the reliability of the motor operation.

Technical solution: The present invention adopts the following technical solution:

A high-speed generator using a radially layered composite integral permanent magnet outer rotor, which is characterized in that: the high-speed motor includes an outer rotor and a stator arranged in the outer rotor; the stator is arranged in an axial through hole of the outer rotor, and the stator is connected to the outer rotor. There is a gap between the rotors;

The stator includes a stator core and a stator winding; the stator winding is arranged in a stator slot opened on the outer wall of the stator core, and the opening of the stator slot faces the outer rotor;

The rotor includes a rotor yoke and three hybrid permanent magnet structural unit layers; the three hybrid permanent magnet structural unit layers are divided into an outer permanent magnet structural unit layer, a middle permanent magnet structural unit layer and an inner permanent magnet structural unit layer; the inner permanent magnet The structural unit layer, the middle permanent magnet structural unit layer and the outer permanent magnet structural unit layer are connected and arranged in sequence from the inside to the outside, and the outer permanent magnet structural unit layer is arranged on the inner wall of the through hole of the rotor yoke;

Each hybrid permanent magnet structural unit layer is composed of an outer carbon fiber or glass fiber layer and an internal hybrid permanent magnet material layer; after the three hybrid permanent magnet structural unit layers are combined, a hybrid permanent magnet material layer is formed and the carbon fiber or glass fiber layer is tied alternately In the structure, the carbon fiber or glass fiber layer of the outer permanent magnet structural unit layer is connected to the inner wall of the through hole of the rotor yoke. This new hybrid permanent magnet structure is a new hybrid permanent magnet material and carbon fiber that are alternately bound. No matter how many layers there are, the new hybrid permanent magnet material faces the stator winding, and then a layer of carbon fiber is added outside the layer facing the stator winding.

Winding pressure plates are also provided at both ends of the stator. (The winding pressure plate is made of insulating and thermally conductive material. Its main function is to fix the ends of the winding. At the same time, the pressure plate can effectively exchange heat between the winding ends and the stator, which is beneficial to reducing the temperature rise of the winding ends.)

A layer of carbon fiber is tied to the inner wall of the innermost hybrid permanent magnet unit, thereby forming an outer rotor high-speed permanent magnet motor rotor with a layered binding structure of hybrid permanent magnet materials.

There are three hybrid permanent magnet structural unit layers, from the inside to the outside. As the number of unit layers increases, the content of the permanent magnet material magnetic powder in the hybrid permanent magnet material layer gradually decreases, and the thickness of the carbon fiber or glass fiber layer gradually increases. The outermost layer The bundled carbon fiber or glass fiber layer has the largest thickness, and the mixed permanent magnet material layer is fully magnetized to form a number of poles. (According to the power level of the motor, determine the maximum outer diameter of the motor's rotor, determine the size of the excitation required by the motor, initially estimate the number of rotor layers and the content of magnetic powder, and calculate the magnetic circuit of the motor through multiple iterations to finally determine the points. The number of layers and the content of magnetic powder in each layer. The increase in the thickness of carbon fiber or glass fiber requires accurate finite element calculations to calculate that the thickness of the outer unit layer of carbon fiber or glass fiber is sufficient to ensure the reliability of the inner unit layer of mixed permanent magnet materials.) In general, the thickness is the same The radius of the strapped rotor is proportional to the square.

The stator slots used to set the windings on the stator are pear-shaped slots. The windings are divided into upper and lower layers and are connected by short-distance stacked windings. The windings are wound with multiple thin wires in parallel. (Windings are generally divided into single-layer windings and double-layer windings. Double-layer windings are used here, so they are divided into upper and lower layers. Short-pitch windings include short-pitch stacked windings and short-pitch wave windings; multiple windings are wound in parallel. It uses multiple thin wires to replace the original thick wires to reduce the skin effect.)

The mixed permanent magnet material layer is uniformly mixed with permanent magnet material magnetic powder and resin. (The mixing method of materials is based on accurate finite element calculations, based on the excitation required for motor operation, and then mixing according to the ratio of permanent magnet material magnetic powder and resin 1:1, because if the ratio is too large, it will greatly affect the new permanent magnet after mixing. The integrity and strength of the magnetic material will be difficult to ensure. If the ratio is too small, the excitation will be difficult to achieve, which will increase the overall thickness, and the strength problem will also be revealed.)

The stator core is made of ultra-thin, low-loss cold-rolled non-oriented electrical steel sheets laminated.

The high-speed generator has a stationary shaft in the stator. The stator adopts pear-shaped slots. The windings adopt double-layer short-pitch windings. The winding pressure plates are set at both ends of the stator core. The main feature of its permanent magnet outer rotor is the layered binding structure of hybrid permanent magnet material. The hybrid permanent magnet material is a mixture of permanent magnet material magnetic powder and resin. Each unit layer is composed of an outer layer of carbon fiber (or glass fiber) and an inner layer. It is composed of mixed permanent magnet materials. The outer layer of carbon fiber (or glass fiber) is for fixation, and the inner layer of mixed permanent magnet material is for providing excitation. The hybrid permanent magnet material and carbon fiber (or glass fiber) binding are placed alternately. After binding several unit layers, a layer of carbon fiber is bundled on the outermost layer to ensure the overall strength of the motor rotor, thus forming a radially layered composite integral permanent magnet. Magnetic outer rotor high speed permanent magnet generator rotor. Along the radial direction from the inside to the outside, as the number of unit layers increases, the content of the magnetic powder of the permanent magnet material decreases in sequence, the thickness of the tied carbon fiber (or glass fiber) increases in sequence, and the overall magnetization is performed to form a number of poles.

The carbon fiber and resin in the radially layered outer rotor structure of this hybrid permanent magnet material are both electrically insulating materials, and the permanent magnet material magnetic powder with large electrical conductivity is mixed with the resin and layered with the carbon fiber to form a hybrid permanent magnet material radial The outer rotor with a layered structure can greatly reduce the eddy current loss generated by the permanent magnet material in the rotor, thereby effectively reducing the heat of the rotor; at the same time, because the carbon fiber material has low density, high tensile strength, and is less affected by temperature Features, it can provide safer and more effective protection for the mixed permanent magnet material when the rotor rotates at high speed. The resin can greatly improve the uniformity, integrity and consistency of the permanent magnet material after the magnetic powder is mixed, and avoid the damage of the motor rotor under high-speed operation. This type of rotor uses a radially layered structure of hybrid permanent magnet materials to effectively ensure the strength and reliability of the motor rotor during high-speed rotation.

The stator slots used to set the windings are pear-shaped slots. The windings are divided into upper and lower layers and are connected by short-distance stacked windings. The windings are wound with multiple thin wires in parallel, which can effectively reduce additional losses caused by the skin effect. ; The stator core is made of ultra-thin, low-loss cold-rolled non-oriented electrical steel sheets laminated, which can effectively reduce core losses at high frequencies.

Advantages and effects:

The invention proposes a high-speed permanent magnet generator using a radially layered composite integral permanent magnet outer rotor. The hybrid permanent magnet material used in the outer rotor is composed of permanent magnet material magnetic powder and resin mixed and magnetized to form a number of poles, each of which has a number of poles. The unit layer is composed of an outer layer of carbon fiber (or glass fiber) and an inner layer of mixed permanent magnet material. The outer layer of carbon fiber (or glass fiber) is to fix the internal structure of the rotor to improve its strength. The inner layer of mixed permanent magnet material is to Provide excitation. The hybrid permanent magnet material is alternately placed with carbon fiber (or glass fiber) binding. After binding several unit layers, a layer of carbon fiber is bundled on the outermost layer to ensure the overall strength of the motor rotor, thus forming a radially layered composite integral permanent magnet. External rotor high speed permanent magnet generator rotor. This kind of hybrid permanent magnet material has a layered binding structure. From the inside to the outside of the motor rotor, as the number of unit layers increases, the content of the permanent magnet material magnetic powder decreases, the thickness of the carbon fiber (or glass fiber) increases, and the outermost layer of the rotor has a greater impact on the strength. The requirements are the largest, so the outermost layer of carbon fiber bundled is thicker. In this kind of rotor layered structure, the permanent magnet material magnetic powder is mixed with resin, which can effectively reduce the eddy current loss in the rotor, thereby reducing the heat source of the motor and reducing the temperature rise of the motor. The uniform distribution of permanent magnet material magnetic powder and resin on the circumferential surface of the rotor can ensure the integrity and consistency of the rotor and avoid the uneven edge stress distribution caused by the use of permanent magnet block structures. At the same time, due to the winding of carbon fiber, carbon fiber has the characteristics of low density, high tensile strength, and less affected by temperature, which can ensure the reliable operation of the permanent magnet rotor under high temperature and high speed.

The beneficial effects of the present invention are:

1. This radially layered composite integral permanent magnet outer rotor structure adopts a ring-shaped structure formed by magnetic powder and resin, replacing the block structure of magnet steel blocks and filling blocks in conventional motors. The permanent magnet part of the rotor has no concentrated stress. It ensures the integrity, uniformity and consistency of the high-speed permanent magnet motor rotor, and eliminates permanent magnet block damage caused by excessive local stress caused by edge effects between conventional structural magnet blocks and between magnet steel and filling blocks. problem, thereby improving the tensile strength of the high-speed permanent magnet motor rotor, increasing the rotor speed limit, and increasing the output power of the motor without changing the volume. This is something that cannot be achieved by conventional motors using magnet steel and filling block structures. .

2. This radially layered composite integral permanent magnet outer rotor is composed of 1, 2, 3,..., n unit layers from the inside to the outside. Each unit layer contains a hybrid permanent magnet that provides excitation. Magnetic materials and carbon fiber (or glass fiber) to increase the strength of the rotor, and a layer of carbon fiber is tied to the outermost layer to ensure the overall strength of the rotor. Carbon fiber materials have the characteristics of low density, high tensile strength, and are less affected by temperature. The layered and tied structure of the rotor can greatly ensure the reliability of the hybrid permanent magnet rotor operating at high speed and high temperature.

3. This kind of hybrid permanent magnet material is made of permanent magnet material magnetic powder and resin mixed in proportion. Resin is a poor conductor of electricity. After mixing, it can effectively reduce the eddy current inside the hybrid permanent magnet material, reduce the loss of this part, and solve the problem. Local heating is a serious problem.

4. In this radially layered rotor structure, the conductive permanent magnet material magnetic powder added to the inner unit layer can shield high-frequency electromagnetic waves and reduce the high-frequency eddy current loss of the permanent magnet material magnetic powder in the mixed permanent magnet material of the outer unit layer. This structure can effectively reduce the heat source in the motor rotor and fundamentally solve the problem of overheating of the high-speed motor rotor.

5. This radially layered outer rotor structure has high elastic modulus, high specific strength and low density, which can increase the natural frequency of the rotor and enhance the stable operating range of the motor rotor.

Description of the drawings

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

Figure 1 is a connection state diagram of the present invention;

Figure 2 is an overall structural diagram of the motor of the present invention;

Figure 3 is a schematic diagram of the unit layer structure of the motor rotor of the present invention;

Figure 4 is an axial cross-sectional view of the present invention;

In the picture: 1. Stationary shaft, 2. Winding pressure plate, 3. Stator winding, 4. Rotor yoke, 5. Stator core, 6. Air gap, 7. New hybrid permanent magnet rotor outer layer, 8. New hybrid permanent magnet rotor Middle layer, 9. Inner layer of new hybrid permanent magnet rotor, 10. Winding end, 11. Sliding bearing.

Specific embodiments: The present invention will be described in detail below with reference to the accompanying drawings:

A high-speed generator using a radially layered composite integral permanent magnet outer rotor, which is characterized in that: the high-speed motor includes an outer rotor and a stator arranged in the outer rotor; the stator is arranged in an axial through hole of the outer rotor, and the stator is connected to the outer rotor. There is a gap between the rotors;

The stator includes a stator core 5 and a stator winding 3; the stator winding 3 is arranged in a stator slot opened on the outer wall of the stator core 5, and the opening of the stator slot faces the outer rotor;

The rotor includes a rotor yoke 4 and three hybrid permanent magnet structural unit layers; the three hybrid permanent magnet structural unit layers are divided into an outer permanent magnet structural unit layer 7, a middle permanent magnet structural unit layer 8 and an inner permanent magnet structural unit layer 9. ; The inner permanent magnet structural unit layer 9, the middle permanent magnet structural unit layer 8 and the outer permanent magnet structural unit layer 7 are connected and arranged in sequence from the inside to the outside, and the outer permanent magnet structural unit layer 7 is arranged on the inner wall of the through hole of the rotor yoke 4;

Each hybrid permanent magnet structural unit layer is composed of an outer carbon fiber or glass fiber layer 13 and an inner hybrid permanent magnet material layer 12; the three hybrid permanent magnet structural unit layers are combined to form a hybrid permanent magnet material layer and a carbon fiber or glass fiber layer. In an alternating binding structure, the carbon fiber or glass fiber layer 13 of the outer permanent magnet structural unit layer 7 is connected to the inner wall of the through hole of the rotor yoke 4 .

Winding pressure plates 2 are also provided at both ends of the stator.

A layer of carbon fiber is tied to the inner wall of the innermost hybrid permanent magnet unit, thereby forming an outer rotor high-speed permanent magnet motor rotor with a layered binding structure of hybrid permanent magnet materials.

There are three hybrid permanent magnet structural unit layers, from the inside to the outside. As the number of unit layers increases, the content of the permanent magnet material magnetic powder in the hybrid permanent magnet material layer gradually decreases, and the thickness of the carbon fiber or glass fiber layer gradually increases. The outermost layer The bundled carbon fiber or glass fiber layer has the largest thickness, and the mixed permanent magnet material layer is fully magnetized to form a number of poles.

The stator slots used to set the windings on the stator are pear-shaped slots. The windings are divided into upper and lower layers and are connected by short-distance stacked windings. The windings are wound with multiple thin wires in parallel.

The mixed permanent magnet material layer is uniformly mixed with permanent magnet material magnetic powder and resin.

The stator core is made of ultra-thin, low-loss cold-rolled non-oriented electrical steel sheets laminated.

As shown in Figure 1, the prime mover pulls the electric motor. The motor windings are connected to the rectifier, and after rectification and inversion, the electric energy is fed back to the grid.

As shown in Figure 2, a high-speed permanent magnet generator using a radially layered composite integral permanent magnet outer rotor includes an outer rotor, an inner stator and a stationary shaft; the stator includes a stator core 5, a stator winding 3 and a winding pressure plate 2. The stator The winding 3 is arranged in the stator core 5, the winding pressure plates 2 are arranged at both ends of the stator, and the outer rotor permanent magnet is fixed to the rotor yoke. The radially layered composite integral permanent magnet outer rotor adopts a uniform layered binding structure of hybrid permanent magnet material and carbon fiber. The hybrid permanent magnet material is composed of permanent magnet material magnetic powder and resin mixed and magnetized to form a certain number of poles.

As shown in Figure 3, each unit layer is tied with a layer of carbon fiber (or glass fiber) on the outer layer for fixation, and then a mixed permanent magnet material is added on the inner layer to provide excitation for the motor. The mixed permanent magnet material is uniformly composed of permanent magnet material magnetic powder and resin. Mixing, several unit layers are superimposed to form this radially layered rotor structure, in which resin is a poor conductor of electricity. After mixing, it can effectively reduce the eddy current inside the hybrid permanent magnet material, reduce the loss of this part, and solve its local heating serious problem. At the same time, this layered structure disperses the concentrated stress during high-speed operation of the rotor into each unit layer, thereby greatly increasing the strength of the rotor and improving the rotor speed limit.

As shown in Figure 4, the motor rotor is divided into several unit layers from the inside to the outside in the radial direction according to the content of magnetic powder. The carbon fiber (or glass fiber) in the outer layer of each unit layer is for fixation, and the mixing in the inner layer Permanent magnet materials are used to provide excitation. When the motor is running, the rotor magnetic field is hinged with the stator magnetic field, and the rotor provides excitation. Therefore, in order to better improve the utilization of materials and ensure the reliability of the strength in the outer unit layer, during the processing of the layered rotor, from the inside to the outside, The magnetic powder content in each unit layer decreases in sequence, and the thickness of carbon fiber (or glass fiber) increases in sequence. At the same time, the conductive permanent magnet material magnetic powder added to the inner unit layer can shield high-frequency electromagnetic waves and reduce the high-frequency eddy current loss in the outer unit layer permanent magnet material magnetic powder. This structure can effectively reduce the heat source in the motor rotor, fundamentally reducing the heat source in the motor rotor. Solve the problem of rotor overheating of high-speed permanent magnet motors with outer rotors. This structure ensures the uniformity, integrity and consistency of the rotor in the circumferential direction. At the same time, the rotor structure has high elastic modulus, high specific strength and low density, which can increase the natural frequency of the rotor and enhance the stable operating range of the motor rotor. Carbon fiber materials have the characteristics of low density, high tensile strength, and are less affected by temperature. They can provide safer and more effective protection for permanent magnets when operating at high temperatures and high speeds, and avoid the problem of excessive local stress during high-speed operation of the motor.

The motor has the characteristics of high reliability, simple structure and high rotor strength.

The conductive permanent magnet material magnetic powder added to the inner unit layer of this layered rotor can shield high-frequency electromagnetic waves and reduce the high-frequency eddy current loss of the outer unit layer mixed permanent magnet material magnetic powder. This structure can effectively reduce the heat source in the motor rotor and fundamentally solve the problem of overheating of the high-speed motor rotor. At the same time, this structure ensures the uniformity, integrity and consistency of the motor rotor, and can mechanically solve the problem of permanent magnets being broken due to large tensile stress under high-speed rotation.

Claims (2)

1. A high-speed generator using a radially layered composite integral permanent magnet outer rotor, characterized in that: the high-speed generator includes an outer rotor and a stator arranged in the outer rotor; the stator is arranged in the axial through hole of the outer rotor, There is a gap between the stator and the outer rotor; The stator includes a stator core (5) and a stator winding (3); the stator winding (3) is arranged in a stator slot opened on the outer wall of the stator core (5), and the opening of the stator slot faces the outer rotor; The rotor includes a rotor yoke (4) and three hybrid permanent magnet structural unit layers; the three hybrid permanent magnet structural unit layers are divided into an outer permanent magnet structural unit layer (7), a middle permanent magnet structural unit layer (8) and an inner permanent magnet structural unit layer. The permanent magnet structural unit layer (9); the inner permanent magnet structural unit layer (9), the middle permanent magnet structural unit layer (8) and the outer permanent magnet structural unit layer (7) are connected in sequence from the inside to the outside, and the outer permanent magnet structural unit The layer (7) is arranged on the inner wall of the through hole of the rotor yoke (4); Each hybrid permanent magnet structural unit layer is composed of an outer carbon fiber or glass fiber layer (13) and an internal hybrid permanent magnet material layer (12); the three hybrid permanent magnet structural unit layers are combined to form a hybrid permanent magnet material layer and A structure in which carbon fiber or glass fiber layers are tied alternately, and the carbon fiber or glass fiber layer (13) of the outer permanent magnet structural unit layer (7) is connected to the inner wall of the through hole of the rotor yoke (4); Winding pressure plates (2) are also provided at both ends of the stator; There are three hybrid permanent magnet structural unit layers, from the inside to the outside. As the number of unit layers increases, the content of the permanent magnet material magnetic powder in the hybrid permanent magnet material layer gradually decreases, and the thickness of the carbon fiber or glass fiber layer gradually increases. The outermost layer The bundled carbon fiber or glass fiber layer has the largest thickness, and the mixed permanent magnet material layer is fully magnetized to form a number of poles; A layer of carbon fiber is tied to the inner wall of the innermost hybrid permanent magnet unit, thereby forming an outer rotor high-speed permanent magnet generator rotor with a layered binding structure of hybrid permanent magnet materials; The stator slots used to set the windings on the stator are pear-shaped slots. The windings are divided into upper and lower layers and are connected by short-distance stacked windings. The windings are wound with multiple thin wires in parallel; The mixed permanent magnet material layer is uniformly mixed with permanent magnet material magnetic powder and resin. 2. A high-speed generator using a radially layered composite integral permanent magnet outer rotor according to claim 1, characterized in that: the stator core is made of ultra-thin, low-loss cold-rolled non-oriented electrical steel sheets laminated.