CN114421716A - Permanent magnet generator for offshore wind power and working method thereof - Google Patents

Abstract

The invention provides a permanent magnet generator for offshore wind power and a working method thereof, wherein the permanent magnet generator at least comprises a stator, a rotor and a cooling cavity; the rotor is positioned outside the cooling cavity, and the stator is positioned inside the cooling cavity; the cooling cavity is filled with a cooling medium; in the invention, the whole stator is soaked in the cooling medium, so that the maintenance-free operation or the operation with reduced maintenance times of the offshore unit is realized; the cooling device is suitable for cooling the offshore wind driven generator.

Description

Permanent magnet generator for offshore wind power and working method thereof

Technical Field

The invention belongs to the technical field of generator stator cooling, and particularly relates to a permanent magnet generator for offshore wind power and a working method thereof.

Background

The wind driven generator is an electric power device which converts wind energy into mechanical work, drives the rotor to rotate and finally outputs alternating current; the wind power generator generally comprises components such as a wind wheel, a generator (including a device), a direction regulator (empennage), a tower, a speed-limiting safety mechanism, an energy storage device and the like; at present, the wind driven generator generally adopts water jacket cooling, air-to-air cooling and air direct cooling.

The inventor finds that the existing wind driven generator cooling mode has the following defects:

1. the water jacket cooling, the air-air cooling and the air direct cooling are all used on large scale on land, the maintenance of the land generator is relatively convenient, but the maintenance and the repair have great difficulty for the offshore wind power generation;

2. the water jacket cooling, air-air cooling and air direct cooling all need additional power sources, such as a motor for forced cooling, which not only increases the difficulty of maintenance, increases electric equipment and reduces the efficiency of wind power generation.

Disclosure of Invention

The invention provides a permanent magnet generator for offshore wind power and a working method thereof in order to solve the problems, and in order to meet higher technical requirements of offshore wind power generation and reduce fault frequency and maintenance amount as much as possible, the invention designs a simpler, safer and more efficient generator stator cooling device; in the invention, fluorocarbon (R113 and other refrigerants) with low boiling point, high insulation, non-combustion, non-toxicity and stable chemical property is used as a cooling medium, the stator is wholly soaked in the cooling medium through a good mechanical structure design, the self-circulation of a cooling system is realized, and the operation of the offshore unit without maintenance or with reduced maintenance times is realized.

In order to achieve the above object, in a first aspect, the present invention provides a permanent magnet generator for offshore wind power, which adopts the following technical scheme:

a permanent magnet generator for offshore wind power at least comprises a stator and a rotor, and is provided with a cooling cavity;

the rotor is positioned outside the cooling cavity, and the stator is positioned inside the cooling cavity; and the cooling cavity is filled with a cooling medium.

Further, the stator comprises a stator core, and one end of the stator core is connected with a generator base; the generator base is positioned in the cooling cavity and soaked in the cooling medium.

Furthermore, the stator core is elastically connected with the generator base.

Further, the stator further comprises a stator coil and an end thereof; the liquid level of the cooling medium is lower than the end face of the stator core far away from one end of the generator base and higher than the stator coil far away from one end of the generator base and the end part of the stator coil.

Further, the housing of the stator is provided as a cage structure.

Furthermore, the top of the cooling cavity is an inclined plane, and an inlet and an outlet are respectively formed at two ends of the inclined plane; an air cooler is arranged at the top of the cooling cavity; the air cooler both ends set up first air chamber and second air chamber respectively, first air chamber with the export intercommunication, the second air chamber with the entry intercommunication.

Further, the volume of the first air chamber is larger than the volume of the second air chamber, and the height of the first air chamber is larger than the height of the second air chamber.

Further, the air cooler comprises a plurality of cooling pipes, and two ends of each cooling pipe are respectively communicated with the first air chamber and the second air chamber.

Further, the cooling medium is fluorocarbon.

In order to achieve the above object, in a second aspect, the present invention further provides a method for a permanent magnet generator for offshore wind power, which adopts the following technical scheme:

an operating method of a permanent magnet generator for offshore wind power, which employs the permanent magnet generator for offshore wind power as described in the first aspect, includes:

the stator coil, the end part of the stator coil and the stator iron core are soaked by the cooling medium for heat exchange; the cooling medium with the increased temperature moves upwards, and the temperature of the liquid near the liquid level of the cooling medium is increased; the liquid at the liquid level of the cooling medium is vaporized to absorb heat; the vaporized gas enters the first air chamber through the outlet, and enters the cooler from the first air chamber, the cooling medium is liquefied into liquid by the gas in the cooler, and the liquefied cooling medium flows into the second air chamber and flows into the cooling cavity from the second air chamber and the inlet in sequence.

Compared with the prior art, the invention has the beneficial effects that:

1. in the invention, the whole stator is soaked in the cooling medium, so that the maintenance-free operation or the operation with reduced maintenance times of the offshore unit is realized; the cooling device is suitable for cooling the offshore wind turbine;

2. the stator cage structure of the invention has no stator casing, thus not only reducing the weight of the stator of the generator, but also ensuring better heat exchange between the stator core and the coil and the cooling medium;

3. the whole stator and the base are placed in the cooling medium and glass fiber reinforced plastic cavity, and the elastic mounting structure of the stator cage and the base can prevent high-frequency vibration generated by the stator from being transmitted to the glass fiber reinforced plastic cavity by a unit to cause damage to the glass fiber reinforced plastic cavity;

4. according to the invention, the stator core, the stator coil and the end parts of the stator core and the stator coil are immersed in the cooling medium, and the cooling medium is filled among the stator core, the stator coil and the end parts of the stator core and the stator coil, so that sufficient heat exchange is ensured, and because of the high insulation property of the cooling medium body, the ionization and the electric corrosion of an electric field to the insulation are avoided, and the long-term running reliability of the stator is ensured;

5. the air cooler is arranged above the glass fiber reinforced plastic cavity, and the effect of cooling the air cooler by utilizing the natural flow of air is realized by virtue of the special characteristics of low air temperature and good fluidity of offshore wind power;

6. according to the invention, through the design of the inlet and the outlet at the upper part of the cavity, the air cooler large chamber, the air cooler small chamber and the air cooler structure, the liquid-gas-liquid self-circulation of a cooling medium can be realized, no additional energy is needed, the energy-saving effect is achieved, and the machine halt accident and the maintenance need caused by forced cooling equipment failure are avoided;

7. the cooling medium in the glass cavity is a low-temperature-medium-temperature-vaporization point from the lower part to the upper part, the cooling medium is positioned on the upper surface of the end part of the stator coil to ensure that all coil parts are directly cooled, the cooling medium does not completely submerge the iron core, so that a part of the high-temperature iron core plays a role of vaporizing the cooling medium, liquid-gas-liquid circulation is formed with the air cooler, and the safety and timeliness of cooling are ensured.

Drawings

The accompanying drawings, which form a part hereof, are included to provide a further understanding of the present embodiments, and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the present embodiments and together with the description serve to explain the present embodiments without unduly limiting the present embodiments.

Fig. 1 is a schematic front view of the structure of embodiment 1 of the present invention;

FIG. 2 is a schematic side view of the structure of embodiment 1 of the present invention;

the generator comprises a stator core, a stator coil and an end part of the stator core, wherein the stator core comprises 1 a glass fiber reinforced plastic cavity, 2 a rotor, 3 a stator core, 4 a stator coil and an end part of the stator coil, 5 an inlet, 6 an air cooler small chamber, 7 a stator cage, 8 an elastic connecting device, 9 a generator base, 10 a cavity glass fiber reinforced plastic, 11 an outlet, 12 an air cooler large chamber, 13 an air cooler, 14 a cooling medium liquid level, 15 a glass fiber reinforced plastic cavity top, 16 an air cooler, 17 an inner cavity glass fiber reinforced plastic, 18 and a cooling medium.

The specific implementation mode is as follows:

the invention is further described with reference to the following figures and examples.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Example 1:

as shown in fig. 1, the embodiment provides a permanent magnet generator for offshore wind power, which at least includes a stator and a rotor 2, and a cooling cavity is provided;

the rotor 2 is positioned outside the cooling cavity, and the stator is positioned inside the cooling cavity; the cooling cavity is filled with a cooling medium 18;

in this embodiment, the cooling cavity may be a glass fiber reinforced plastic cavity; as shown in fig. 1 and 2, the glass fiber reinforced plastic chamber 1 is a sealed cooling chamber consisting of a chamber glass fiber reinforced plastic 10 and an inner chamber glass fiber reinforced plastic 17 except for an outlet 11 and an inlet 5.

In the present embodiment, as shown in fig. 1, the stator includes a stator core 3, and one end of the stator core 3 is connected to a generator base 9; the generator base 9 is positioned in the cooling cavity and is soaked in the cooling medium 18; the stator core 3 is elastically connected with the generator base 9, and the elastic connection can be realized by a spring or a bolt provided with an elastic sheet;

whole stator with generator frame 9 places in coolant 11 and glass steel cavity 1, moreover stator core 3 through stator cage (shell) with generator frame 9's elastic mounting structure, can avoid the high-frequency vibration that the stator produced to be passed to for glass steel cavity 1 by the unit, cause the damage of glass steel cavity.

In the present embodiment, the stator further comprises a stator coil and its ends 4; the cooling medium liquid level 14 is lower than the end surface of the stator core 3 far away from one end of the generator base 9, and is higher than the stator coil and the end part 4 thereof far away from one end of the generator base 9; it will be appreciated that the coolant level 14 is higher than the stator coil end 4 and lower than the highest point of the stator core 3.

In this embodiment, the casing of stator sets up to cage structure, and cage structure is stator cage 7, stator cage 7 can set up to the cage that forms by steel pipe welding, stator cage 7 through elastic connection device 8 with generator frame 9 welds together, prevents high-frequency vibration to glass steel's fatigue damage.

In this embodiment, the top of the cooling cavity is an inclined plane, and an inlet 5 and an outlet 11 are respectively formed at two ends of the inclined plane; an air cooler 13 is arranged at the top of the cooling cavity; a first air chamber (an air cooler large chamber 12) and a second air chamber (an air cooler small chamber 6) are respectively arranged at two ends of the air cooler 13, the first air chamber is communicated with the outlet 11, and the second air chamber is communicated with the inlet 5; the volume of the first air chamber is greater than the volume of the second air chamber, and the height of the first air chamber is greater than the height of the second air chamber; the air cooler 13 comprises a plurality of cooling pipes, and two ends of each cooling pipe are respectively communicated with the first air chamber and the second air chamber;

the top 15 of the glass fiber reinforced plastic cavity is provided with an inclined surface with one higher side and one lower side, so that liquid can flow down conveniently; the cooling pipe is arranged the same as the top 15 of the glass fiber reinforced plastic cavity, one end of the cooling pipe is higher, the other end of the cooling pipe is lower, and the cooling pipe is externally provided with a radiating fin; the first air chamber and the second air chamber are used as two cooling chambers, and the air cooler is formed by combining a plurality of cooling pipes and fins penetrating the cooling pipes.

In this embodiment, the cooling medium is a fluorocarbon, and the fluorocarbon may be a refrigerant such as R113.

The working principle or process of the embodiment is as follows:

the stator heating heat source is the stator coil and the end part 4 and the stator core 3, the stator coil and the end part 4 and the stator core 3 are soaked by the cooling medium 18, and the cooling medium 18 can ensure that the stator coil and the end part 4 and the stator core 3 can carry out sufficient heat exchange; the cooling medium 18 with the increased temperature will go upwards, resulting in a higher temperature of the liquid near the cooling medium level 14; the temperature of the stator core 3 is the highest temperature of the whole generator stator, and the position of the cooling medium liquid level 14 is a main vaporization point to take away a large amount of energy; the vaporized gas moves to a high position along the top 15 of the glass fiber reinforced plastic cavity to drive the gas to move; the cooling medium is liquefied into liquid from gas due to the lower external temperature of the cooling pipe, the volume of the cooling pipe of the air cooler small chamber cooler 13 is reduced, and the flow of the gas from the air cooler small chamber glass fiber reinforced plastic cavity 1 to the air cooler small chamber air cooler large chamber 12 is accelerated; the cooling medium 18 liquefied by the cooling pipe of the cooler 13 flows into the air cooler small chamber cooling chamber small chamber 6 and sequentially flows into the glass fiber reinforced plastic cavity 1 from the air cooler small chamber cooling chamber small chamber 6 and the inlet 5 of the glass fiber reinforced plastic cavity 1 of the air cooler small chamber, so that the whole circulation from the liquid state to the gas state and then to the liquid state is completed;

when the gasified cooling medium 18 passes through the cooling pipe of the cooler 13, heat exchange is performed, the temperature of air around the cooling pipe rises, air circulation is caused, natural cooling is formed, and the device is suitable for offshore wind power operation.

Example 2:

the embodiment further illustrates the permanent magnet generator for offshore wind power in embodiment 1; the method specifically comprises the following steps:

the stator iron core 3 and the stator coil form a whole, and are embedded into a steel cage 7 formed by welding steel pipes to form a generator stator, and the stator has no stator shell, so that the weight of the stator is reduced, and the heat dissipation of the stator iron core and the coil is facilitated; the whole stator core, the stator coil and the stator cage 7 are welded on the generator base through the elastic support formed by the steel pipes, so that the transmission of high-frequency vibration generated in the running process of the generator to the base can be effectively reduced, and the damage to the lower base of the glass fiber reinforced plastic cavity under the base is avoided.

The whole stator core 3, the stator coil, the stator cage 7 and the generator base 9 form a whole and are arranged in a closed structure formed by glass fiber reinforced plastics; an air cooler is arranged at the upper part of the closed structure, and the air cooler consists of two cooling chambers, a plurality of cooling pipes and fins penetrating through the cooling pipes; when the device is operated, cooling medium is injected into a closed environment formed by glass fiber reinforced plastic, and the position of the end part of the coil is submerged at the highest position of the liquid level; when the motor runs, the heat emitted by the iron core and the coil heats the cooling medium, the liquid of the cooling medium which is not soaked near the iron core is accelerated to be vaporized, and the vaporized gas enters the large chamber 12 of the cooler; the cooling pipe of the cooler 13 absorbs the temperature of the vaporized gas, so that the temperature of the cooling pipe rises, the air outside the cooling pipe rises, the flow of the air around the cooling pipe is accelerated, and the cooling of the cooling pipe is accelerated; the cooling medium changes phase from gas to liquid due to temperature reduction in the cooling pipe, and the liquid flows into the cooler chamber 6 from the cooling pipe; the pressure in the cooling pipe is reduced, so that the continuous supplementary gas of the large chamber of the cooler is caused, and self circulation is formed.

The stator is not provided with a stator shell, the cooling medium in the glass fiber reinforced plastic cavity 1 flows freely and exchanges heat, and the air gaps around the iron core and the coil are filled with the cooling medium liquid, so that the heat exchange can be carried out fully.

The liquid level is above the end coils of the stator but does not submerge all the iron cores; the liquid surface is in contact with the iron core with higher temperature, the position is the main gasification position of the cooling medium changed from liquid to gas, and the temperature is lower and lower from the liquid surface.

The top of the glass fiber reinforced plastic cavity 1 is provided with a slope device, which is beneficial to the high-temperature gas to flow upwards and enter the large chamber 12 of the cooler, is beneficial to the gas in the cooler to flow downwards along the slope after being liquefied and then flow to the small chamber 6 of the air cooler and flow into the upper layer of the liquid level, and the liquid with lower temperature is mixed with the liquid with higher temperature, so that the mixing in the liquid is facilitated.

The glass fiber reinforced plastic cavity 1 is positioned outside the rotor and does not cool the generator rotor.

The generator stator and the generator base 9 adopt an elastic supporting structure, and vibration damage of iron core vibration to the glass fiber reinforced plastics is reduced.

The silicon steel sheet of the generator is laminated in a stator cage composed of steel pipes, a stator coil is embedded in the stator iron core, and a closed shell is not arranged outside the stator cage.

The air cooler 13 is divided into an air cooler large chamber 12, an air cooler small chamber 6, air cooler pipes and air cooler fins, and the air cooler 13 is arranged in a state that the air cooler large chamber is high in position 12 and the air cooler small chamber 6 is low in position and one end of the air cooler small chamber is high and the other end of the air cooler small chamber is low so as to be beneficial to the backflow of liquefied liquid; the cooling pipe heats the surrounding air to increase the temperature of the air, thereby facilitating the cooling of the air cooler pipe and forming self-cooling.

The internal cooling self-circulation of generator, entering air cooler big room 12 after the coolant vaporization, gas liquefaction after the cooling in the cooling tube leads to air cooler big room 12 to attract more gas and is inhaled air cooler big room 12, and the liquid in the cooling tube all leads to intraductal atmospheric pressure to descend with the liquefaction of the intraductal gas of cooling down along the pipe, causes gas to get into air cooler big room 12, and gas liquefaction flows into air cooler cell 6 in the cooling tube, and liquid flows into in glass steel cavity 1, forms whole cooling cycle.

Example 1:

the embodiment provides a working method of a permanent magnet generator for offshore wind power, which adopts the permanent magnet generator for offshore wind power as described in the first aspect, and includes:

the stator coil, the end part of the stator coil and the stator iron core are soaked by the cooling medium for heat exchange; the cooling medium with the increased temperature moves upwards, and the temperature of the liquid near the liquid level of the cooling medium is increased; the liquid at the liquid level of the cooling medium is vaporized to absorb heat; the vaporized gas enters the first air chamber through the outlet, and enters the cooler from the first air chamber, the cooling medium is liquefied into liquid by the gas in the cooler, and the liquefied cooling medium flows into the second air chamber and flows into the cooling cavity from the second air chamber and the inlet in sequence.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and those skilled in the art can make various modifications and variations. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present embodiment should be included in the protection scope of the present embodiment.

Claims (10)

1. A permanent magnet generator for offshore wind power at least comprises a stator and a rotor, and is characterized in that a cooling cavity is arranged;

the rotor is positioned outside the cooling cavity, and the stator is positioned inside the cooling cavity; and the cooling cavity is filled with a cooling medium.

2. The permanent magnet generator for offshore wind power as claimed in claim 1, wherein the stator comprises a stator core, and one end of the stator core is connected with a generator base; the generator base is positioned in the cooling cavity and soaked in the cooling medium.

3. The permanent magnet generator for offshore wind power as claimed in claim 2, wherein said stator core is elastically connected to said generator base.

4. The permanent magnet generator for offshore wind power according to claim 2, wherein said stator further comprises stator coils and ends thereof; the liquid level of the cooling medium is lower than the end face of the stator core far away from one end of the generator base and higher than the stator coil far away from one end of the generator base and the end part of the stator coil.

5. A permanent magnet generator for offshore wind power according to claim 2, wherein the housing of the stator is provided as a cage structure.

6. The permanent magnet generator for offshore wind power as claimed in claim 1, wherein the top of the cooling cavity is an inclined plane, and an inlet and an outlet are respectively formed at two ends of the inclined plane; an air cooler is arranged at the top of the cooling cavity; the air cooler both ends set up first air chamber and second air chamber respectively, first air chamber with the export intercommunication, the second air chamber with the entry intercommunication.

7. The permanent magnet generator for offshore wind power according to claim 6, wherein the volume of said first air chamber is larger than the volume of said second air chamber, and the height of said first air chamber is larger than the height of said second air chamber.

8. The permanent magnet generator for offshore wind power as claimed in claim 6, wherein the air cooler comprises a plurality of cooling pipes, and both ends of the cooling pipes are respectively communicated with the first air chamber and the second air chamber.

9. The permanent magnet generator for offshore wind power as claimed in claim 1, wherein the cooling medium is fluorocarbon.

10. A method for operating a permanent magnet generator for offshore wind power, characterized in that a permanent magnet generator for offshore wind power according to any one of claims 1 to 9 is used, comprising:

the stator coil, the end part of the stator coil and the stator iron core are soaked by the cooling medium for heat exchange; the cooling medium with the increased temperature moves upwards, and the temperature of the liquid near the liquid level of the cooling medium is increased; the liquid at the liquid level of the cooling medium is vaporized to absorb heat; the vaporized gas enters the first air chamber through the outlet, and enters the cooler from the first air chamber, the cooling medium is liquefied into liquid by the gas in the cooler, and the liquefied cooling medium flows into the second air chamber and flows into the cooling cavity from the second air chamber and the inlet in sequence.

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