Offshore wind power double-fed unit, cabin system and heat dissipation method thereof

Abstract

The application discloses an offshore wind power double-fed unit, a machine cabin system and a heat dissipation method thereof, and relates to the technical field of generator units. The machine cabin system comprises a machine cabin cover, a fresh air supply module, a gear box air cooling module and a generator air cooling module. The fresh air supply module is connected with the outside of the cabin room through the machine cabin cover at the air inlet end and is connected with the cabin room at the air outlet end, and is used for supplying filtered clean air to the cabin room to establish and maintain a slightly positive pressure environment of the cabin room and to purge and cool the gear box. The gear box air cooling module comprises a first air cover used for covering the heat dissipation part of the gear box, and the first air cover is connected with the outside of the cabin room through the machine cabin cover to form a first air duct isolated from the cabin room. The generator air cooling module comprises a second air cover used for covering the heat dissipation part of the generator, and the second air cover is connected with the outside of the cabin room through the machine cabin cover to form a second air duct isolated from the cabin room. The second air inlet of the second air cover is located in the cabin room and is provided with an air valve. The machine cabin system solves the contradiction between poor sealing and insufficient heat dissipation capacity of the traditional air cooling heat dissipation design in the offshore high-salt-mist environment.

Description

Technical Field

[0001] This invention relates to the field of generator set technology, and more specifically, to an offshore wind turbine doubly fed by a generator set and its nacelle system and heat dissipation method. Background Technology

[0002] Offshore wind power, as an important component of clean energy, operates in an environment characterized by high salt spray, high humidity, strong winds and rain, high vibration, and variable temperatures. This places stringent requirements on the heat dissipation design and environmental protection of wind turbine units, especially the nacelle system of the doubly fed wind turbine, which is a core component.

[0003] Currently, the heat dissipation design for high-power heat-generating equipment such as gearboxes and generators in the nacelle of offshore wind turbines mainly adopts the following two heat dissipation designs, but both have prominent problems:

[0004] Water-cooled heat dissipation design: While this solution offers high heat dissipation efficiency, the water-cooled system requires additional external water-cooling fins, circulating water pumps, water-cooled piping, and supporting trusses, significantly increasing hardware costs and subsequent maintenance expenses. Especially in the high-vibration, high-salt-spray environment of the sea, water-cooled pipe joints are prone to loosening, leading to coolant leaks; salt spray corrosion can cause perforation and damage to water-cooled components; and in low-temperature winter conditions, there is a risk of pipe freezing and cracking due to improper antifreeze mixing or heating device malfunctions, resulting in unit shutdown for maintenance and severely impacting power generation. Therefore, water-cooled heat dissipation design is both costly and unreliable.

[0005] Air-cooled heat dissipation design: While this solution is simple in structure and low in cost, it also has two major problems. First, the engine room's airtightness is insufficient, making it difficult to effectively prevent the intrusion of salt spray and moisture, leading to accelerated corrosion of equipment inside the engine room and a significant reduction in service life. Second, its heat dissipation capacity is limited, especially in high-temperature environments in summer, as it cannot effectively remove the heat generated by the gearbox and generator, causing equipment to frequently operate at reduced power due to overheating. This makes it difficult for air-cooled heat dissipation design to simultaneously achieve both protection and heat dissipation capabilities in marine environments.

[0006] In addition, existing offshore generator set electric slip ring cooling systems mostly adopt the scheme of collecting and filtering carbon powder inside the cabin. Carbon powder is very prone to leakage during the filtration and collection process, thereby polluting the internal environment of the engine room, posing a serious threat to the normal operation of other electrical equipment in the engine room, reducing the service life of equipment and the stability of unit operation.

[0007] Therefore, how to avoid the shortcomings of existing water-cooled heat dissipation designs, such as high cost and poor reliability due to environmental influences, and effectively solve the contradiction between nacelle airtightness and heat dissipation capacity in existing air-cooled designs, so as to improve the economy and reliability of offshore wind turbines, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a nacelle system for offshore wind turbines with doubly fed feeder systems. This system constructs an air duct isolated from the nacelle through a fully air-cooled modular design and utilizes a fresh air supply module that can maintain a slight positive pressure inside the nacelle. This avoids the high cost and low reliability of water-cooled heat dissipation design, while solving the contradiction of poor airtightness and insufficient heat dissipation capacity of traditional air-cooled heat dissipation design in the high salt spray environment at sea, thereby improving the unit's economy, reliability and heat dissipation efficiency.

[0009] Another object of the present invention is to provide an offshore wind turbine doubly fed induction generator (DFIG) including the above-described offshore wind turbine nacelle system and a heat dissipation method applied to the system.

[0010] To achieve the above objectives, the present invention provides the following technical solution:

[0011] A doubly-fed induction generator nacelle system for offshore wind turbines includes:

[0012] The cabin canopy contains a sealed compartment.

[0013] A fresh air supply module is located in the cabin. The air inlet of the fresh air supply module passes through the cabin cover and connects to the outside of the cabin, and the air outlet connects to the cabin. It is used to supply filtered clean air to the cabin to establish and maintain a micro-positive pressure environment in the cabin and to purge the cooling gearbox.

[0014] The gearbox air-cooled module includes a first shroud for covering the heat dissipation part of the gearbox. The air inlet and air outlet of the first shroud both penetrate the nacelle cover and connect to the outside of the cabin to form a first air duct isolated from the cabin.

[0015] The generator air-cooled module includes a second shroud for covering the heat dissipation part of the generator. The first air inlet and the air outlet of the second shroud both penetrate the nacelle cover and connect to the outside of the cabin to form a second air duct isolated from the cabin. The second air inlet of the second shroud is located in the cabin and is provided with an air valve. When the air valve is opened, it can introduce clean air from the cabin into the second air duct.

[0016] A doubly-fed induction generator for offshore wind power includes:

[0017] The aforementioned offshore wind turbine nacelle system;

[0018] The spindle assembly is connected to the head of the nacelle cover via a flange, and a first seal is provided between the flange and the nacelle cover;

[0019] The tower is connected to the bottom of the nacelle cover via a yaw drive system, and a second seal is provided at the connection between the tower and the nacelle cover;

[0020] The gearbox includes a gearbox body and a gearbox radiator, both disposed within the compartment. The input end of the gearbox body is connected to the output end of the spindle assembly. The gearbox radiator is located at the rear of the compartment and is connected to the lubrication circuit of the gearbox body via an oil cooling pipe.

[0021] The generator includes a generator body disposed in the cabin and a generator radiator disposed on the generator body. The input end of the generator body is connected to the output end of the gearbox, and the output end of the generator body is connected to an electric slip ring.

[0022] A defrosting machine is located inside the aforementioned compartment.

[0023] A heat dissipation method is applied to the nacelle system of the aforementioned offshore wind turbine double-fed induction generator, the heat dissipation method comprising:

[0024] The fresh air supply module is controlled to operate, a slightly positive pressure environment is established in the cabin, and the gearbox body of the gearbox is directionally purged to assist in heat dissipation.

[0025] The gearbox air-cooling module and the generator air-cooling module are activated to drive the outside air through their respective air ducts, which are isolated from the cabin, to provide basic air-cooling for the gearbox radiator and the generator.

[0026] The generator's operating temperature is acquired in real time, and the air supply volume of the fresh air supply module and the opening of the air valve are controlled according to the operating temperature to enhance the generator's air cooling.

[0027] The offshore wind turbine nacelle system provided by this invention has the following beneficial effects:

[0028] The unit adopts a fully air-cooled modular design, comprising an air-cooled gearbox module and an air-cooled generator module. Both modules allow outside air to flow through their respective air ducts, providing basic air cooling for the gearbox and generator's heat dissipation components. This design avoids the complex water-cooling system (including water-cooled fins, circulating pumps, piping, antifreeze, and supporting trusses) commonly relied upon in traditional offshore units, thereby significantly reducing hardware and maintenance costs and improving the unit's economic efficiency.

[0029] The air ducts formed by the gearbox air-cooling module and the generator air-cooling module are isolated from the cabin, ensuring that the air-cooling paths of the gearbox and generator's heat dissipation units are completely isolated from the cabin, preventing high-salt-spray and high-humidity marine air from entering the cabin. Furthermore, the fresh air supply module continuously supplies filtered air to the sealed cabin and maintains positive pressure, preventing high-salt-spray and high-humidity marine air from entering the sealed cabin through gaps in the engine hood. This design effectively prevents corrosion of core components such as the gearbox and generator by high-salt-spray and high-humidity marine air, thereby improving the unit's corrosion resistance in high-salt-spray and high-humidity marine environments and ensuring stable unit operation.

[0030] Building upon basic air-cooling, the system employs two additional mechanisms: firstly, a fresh air supply module purifies the gearbox for auxiliary cooling; secondly, by controlling the air valves on the second shroud, clean air from the cabin is introduced into the second air duct used for the air-cooled generator under high-temperature conditions, thus enhancing air-cooling of the generator. This design allows the system to balance protection and heat dissipation in a marine environment. In other words, while preventing untreated marine air from directly entering the cabin, the clean air introduced by the fresh air supply module can promptly remove heat generated by the gearbox and generator in high-temperature environments, effectively preventing the equipment from being forced to reduce power due to overheating and ensuring stable operation of the unit. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0032] Figure 1 A schematic diagram of the structure of an offshore wind turbine doubly fed induction generator unit including a nacelle system, provided by the present invention;

[0033] Figure 2 A schematic diagram of the installation of a nacelle system for an offshore wind turbine provided by the present invention in an offshore wind turbine, from one perspective;

[0034] Figure 3 A second perspective view of the installation schematic diagram of the nacelle system of an offshore wind turbine provided by the present invention in an offshore wind turbine double-fed generator;

[0035] Figure 4 A schematic diagram of the installation of a nacelle system for an offshore wind turbine provided by the present invention in an offshore wind turbine, from perspective three;

[0036] Figure 5This is a schematic diagram of the air-cooled gearbox of the gearbox air-cooled module provided by the present invention;

[0037] Figure 6 This is a schematic diagram of the air-cooled generator module provided by the present invention.

[0038] Figure 7 This is a schematic diagram of the air-cooled electric slip ring for the air-cooled module provided by the present invention;

[0039] Figure 8 This is a schematic diagram of the fresh air supply module provided by the present invention facing the gearbox body.

[0040] Figure 9 This is a schematic diagram of the filtration and ventilation of the fresh air supply module provided by the present invention.

[0041] Figure label:

[0042] 1-Navy canopy; 11-Compartment;

[0043] 2-Fresh air supply module; 21-Fourth air hood; 22-Gas-liquid separator; 23-Salt spray filter; 24-Fourth fan; 231-Filter frame; 232-Filter cotton; 233-Intermediate air duct; 234-Sealed window cover;

[0044] 3-Gearbox air-cooled module; 31-First air shroud;

[0045] 4-Generator air-cooled module; 41-Second shroud; 42-Second fan; 43-Air valve; 411-First air inlet; 412-Second air inlet;

[0046] 5-Electric slip ring air-cooled module; 51-Third fan shroud; 52-Third fan; 53-Electric slip ring exhaust valve;

[0047] 6-Spindle assembly; 7-Yaw drive system; 8-Gearbox body; 9-Oil cooling pipe; 10-Generator body; 12-Defrosting machine; 13-Control cabinet. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] The core of this invention is to provide a nacelle system for offshore wind turbines with doubly fed feeder systems. This system constructs an air duct isolated from the nacelle through a fully air-cooled modular design and utilizes a fresh air supply module that can maintain a slight positive pressure inside the nacelle. This avoids the high cost and low reliability of water-cooled heat dissipation design, while solving the contradiction of poor airtightness and insufficient heat dissipation capacity of traditional air-cooled heat dissipation design in the high salt spray environment at sea, thereby improving the unit's economy, reliability and heat dissipation efficiency.

[0050] Another core aspect of this invention is to provide an offshore wind turbine doubly fed induction generator (DFIG) including the aforementioned nacelle system and a heat dissipation method applied to this system.

[0051] Please refer to Figure 2 The present invention provides a specific embodiment of the nacelle system of an offshore wind turbine double-fed induction generator, including a nacelle cover 1, a fresh air supply module 2, a gearbox air-cooled module 3, and a generator air-cooled module 4.

[0052] Please refer to Figure 1 The interior of the engine room cover 1 is a sealed compartment 11. This compartment 11 is isolated from the external marine environment to prevent marine air from entering the engine room cover 1 (i.e., compartment 11) and corroding the core components of the unit (such as gearbox, generator, or main shaft assembly 6).

[0053] Please refer to Figure 2 and Figure 4 The fresh air supply module 2 is located in the compartment 11. The air inlet of the fresh air supply module 2 passes through the hood 1 and connects to the outside of the compartment 11, and the air outlet connects to the compartment 11. The fresh air supply module 2 has the functions of air intake and air supply and air filtration. It is used to supply filtered clean air to the compartment 11 to establish and maintain a micro positive pressure environment in the compartment 11, and can also purge the cooling gearbox.

[0054] Please refer to Figure 2 and Figure 3 The gearbox air-cooling module 3 includes a first shroud 31 for covering the heat dissipation part of the gearbox. The air inlet and air outlet of the first shroud 31 both penetrate through the nacelle cover 1 and connect to the outside of the compartment 11 to form a first air duct isolated from the compartment 11. It should be noted that the first shroud 31 is an independent shell that covers the main heat dissipation parts of the gearbox (such as the gearbox radiator).

[0055] Please refer to Figure 2 , Figure 3 and Figure 4The generator air-cooling module 4 includes a second shroud 41 for covering the generator's heat dissipation section. The first air inlet 411 and air outlet of the second shroud 41 both penetrate the nacelle cover 1 and connect to the outside of the compartment 11, forming a second air duct isolated from the compartment 11. The second air inlet 412 of the second shroud 41 is located in the compartment 11 and is equipped with a damper 43. When the damper 43 is open, it can introduce clean air from the compartment 11 into the second air duct. It should be noted that the second shroud 41 is an independent outer shell that covers the generator's main heat dissipation components (such as the generator radiator).

[0056] The operating steps of the offshore wind turbine nacelle system in the above embodiment during unit operation are as follows:

[0057] Establish a slightly positive pressure environment in the chamber 11: The fresh air supply module 2 is activated, drawing in air from outside the chamber 11. After being purified by the internal filtration unit (such as the salt spray filter 23), the air becomes clean air and is delivered into the sealed chamber 11 through the air supply equipment at its outlet, and performs directional blowing to assist in heat dissipation of the gearbox (such as its gearbox body 8).

[0058] In this step, because the air supply volume is designed to exceed the possible natural leakage of compartment 11, the air pressure inside the compartment is slightly higher than the external environment, creating a slightly positive pressure environment. This positive pressure can prevent outside air containing salt spray and moisture (i.e., sea air) from intruding through gaps, providing a protected, dry, and clean basic operating environment for all equipment inside the compartment. In addition, the fresh air supply module 2 directly blows air onto the gearbox to assist in heat dissipation, which can work in conjunction with the basic air-cooled heat dissipation of the first air duct described below, enhancing the cooling effect of the gearbox and ensuring timely heat dissipation in high-temperature environments such as summer, avoiding overheating and forced power reduction operation.

[0059] Start the gearbox air-cooling module 3 and the generator air-cooling module 4 to drive the outside air through their respective air ducts, which are isolated from the compartment 11, to perform basic air-cooling on the main heat dissipation parts of the gearbox and generator (such as the gearbox radiator and the generator radiator).

[0060] In this step, both the first and second air ducts are isolated from the compartment 11, ensuring that the air cooling path of the gearbox and generator's heat dissipation section is completely isolated from the compartment 11, and that the heat dissipation process does not occupy or pollute the air inside the compartment.

[0061] Subsequently, the airflow into the second air duct is dynamically and precisely adjusted according to the generator temperature. Specifically, when the generator's operating temperature is normal, the air valve 43 is closed, and the generator air-cooling module 4 operates independently. Outside air enters the second air shroud 41 only through the first air inlet 411, cools the generator, and is then discharged from the air outlet, forming an isolated second air duct. This mode ensures the generator's basic heat dissipation requirements and corrosion protection. When the generator's operating temperature rises, the air valve 43 is opened under control. At this time, positive pressure clean air in the compartment is introduced into the second air shroud 41 through the second air inlet 412 to enhance the generator's air-cooling heat dissipation, thereby effectively preventing the generator from triggering power reduction operation due to excessive temperature and ensuring stable unit operation.

[0062] In summary, the offshore wind turbine nacelle system described in the above embodiments has the following effects:

[0063] The system adopts a fully air-cooled modular design, comprising an air-cooled gearbox module 3 and an air-cooled generator module 4. Both modules allow outside air to flow through their respective air ducts, providing basic air cooling for the gearbox and generator's heat dissipation components. This design avoids the complex water-cooling system (including water-cooled fins, circulating pumps, piping, antifreeze, and support trusses) commonly relied upon in traditional offshore units, thereby significantly reducing hardware and maintenance costs and improving the unit's economic efficiency.

[0064] The air ducts formed by the gearbox air-cooling module 3 and the generator air-cooling module 4 are isolated from the compartment 11, ensuring that the air-cooling paths of the gearbox and generator's heat dissipation parts are completely isolated from the compartment 11, preventing high-salt-spray and high-humidity marine air from entering the compartment 11. Furthermore, the fresh air supply module 2 continuously supplies filtered air to the sealed compartment 11 and maintains positive pressure, preventing high-salt-spray and high-humidity marine air from entering the sealed compartment 11 through the gaps in the nacelle cover 1. This design effectively prevents corrosion of core components such as the gearbox and generator by high-salt-spray and high-humidity marine air, thereby improving the unit's corrosion resistance in high-salt-spray and high-humidity marine environments and ensuring stable unit operation.

[0065] like Figure 5 , Figure 6 and Figure 9As shown, based on basic air-cooled heat dissipation, on the one hand, the fresh air supply module 2 can purge the gearbox for auxiliary heat dissipation; on the other hand, by controlling the air valve 43 set on the second air shroud 41, clean air from inside the cabin is introduced into the second air duct for the air-cooled generator under high-temperature conditions to enhance air-cooled heat dissipation for the generator. This design allows the system to balance protection and heat dissipation capabilities in a marine environment. That is, while preventing untreated marine air from directly entering the cabin 11, if the unit is in a high-temperature environment, the clean air introduced by the fresh air supply module 2 can promptly remove the heat generated by the gearbox and generator, effectively preventing the equipment from being forced to reduce power due to overheating and ensuring stable operation of the unit.

[0066] Based on the above embodiments, as a further preferred embodiment, the nacelle system of the offshore wind turbine also includes a control unit (such as a computer system), which is communicatively connected to the fresh air supply module 2, the gearbox air-cooling module 3, and the generator air-cooling module 4.

[0067] In this embodiment, the fresh air supply module 2, the gearbox air-cooling module 3, and the generator air-cooling module 4 all have air intake and exhaust functions. The control unit is connected to the fresh air supply module 2, the gearbox air-cooling module 3, and the generator air-cooling module 4 via wired or wireless communication.

[0068] The control unit can start and stop the fresh air supply module 2, the gearbox air-cooling module 3, and the generator air-cooling module 4. When the fresh air supply module 2 is started, it can drive filtered outside air into the cabin and directly blow it onto the gearbox body 8. Conversely, when it is turned off, the above operation is stopped. When the gearbox air-cooling module 3 and the generator air-cooling module 4 are started, they can drive outside air through the first and second air ducts, which are isolated from the cabin 11, to provide basic cooling for the main heat dissipation parts of the gearbox and generator. Conversely, when they are turned off, the above operation is stopped.

[0069] Regarding the precise maintenance of a slightly positive pressure environment within the cabin, in one specific embodiment, the control unit receives signals from pressure sensors installed in the cabin 11 in real time and controls the airflow of the fresh air supply module 2 based on the pressure signals to maintain a slightly positive pressure environment in the cabin 11. Specifically, the control unit compares the real-time pressure value with a preset positive pressure threshold range. If the pressure is below the lower limit, it sends a command to the fresh air supply module 2 to increase its airflow; if the pressure is above the upper limit, it commands it to reduce its airflow, thereby precisely maintaining a slightly positive pressure environment within the cabin and preventing salt spray intrusion caused by pressure fluctuations.

[0070] Regarding the precise switching between the basic cooling and enhanced cooling modes of the generator, in one specific embodiment, the control unit receives the temperature sensor signal installed on the generator in real time, and controls the air supply volume of the fresh air supply module 2 and the opening degree of the air valve 43 according to the temperature signal.

[0071] It should be noted that a first temperature threshold T1 and a second temperature threshold T2 can be preset in the control unit, where T1>T2.

[0072] When the generator operating temperature is ≤T2, it indicates that the generator operating temperature is normal, and the basic cooling mode can effectively dissipate heat. The control unit only needs to make the generator air-cooling module 4 operate independently (such as starting its built-in second fan 42) and keep the air valve 43 in the closed state. Outside air enters the second air shroud 41 only through the first air inlet 411, cools the generator, and is discharged from the air outlet, forming an isolated second air duct. This mode ensures the generator's basic heat dissipation requirements and corrosion protection.

[0073] When T2 < generator operating temperature ≤ T1, it indicates that the generator operating temperature is relatively high, which is the first enhanced cooling mode. That is, only the air valve 43 needs to be adjusted to effectively dissipate heat. The control unit adjusts the opening of the air valve 43 proportionally (for example, the higher the temperature, the larger the opening), introducing an appropriate amount of clean air from the compartment into the second air duct to increase the air intake of the second air duct and enhance the generator's air-cooled heat dissipation.

[0074] When the generator operating temperature exceeds T1, it indicates that the generator operating temperature is too high. This triggers the second enhanced cooling mode, which requires simultaneous adjustment of the airflow from both the damper 43 and the fresh air supply module 2 to achieve effective heat dissipation. The control unit controls the damper 43 to open to its maximum extent and controls the fresh air supply module 2 to increase the airflow, providing a sufficient and cooled clean air source to enhance the generator's cooling capacity to the maximum extent.

[0075] The aforementioned generator cooling mode switching method ensures that the generator's heat load matches the system's cooling capacity, thereby guaranteeing stable operation of the generator within a safe temperature threshold while preventing unnecessary energy consumption in the system.

[0076] In addition, the control unit can control the airflow of the fresh air supply module 2 based on the gearbox oil temperature signal. Under high temperature and high load conditions, it ensures that the airflow is matched with the heat of the gearbox to effectively blow away heat from the gearbox body 8.

[0077] In summary, the invention adds a control unit, enabling the system to operate intelligently, improving system energy efficiency, operational stability, and heat dissipation precision, thus giving the system better adaptability in complex and ever-changing marine environments.

[0078] Based on the above embodiments, as a further preferred option, please refer to... Figure 2 and Figure 7The nacelle system of the offshore wind turbine also includes an electric slip ring air-cooled module 5. The electric slip ring air-cooled module 5 includes a third fan 52 and a third shroud 51 for covering the electric slip ring. The air outlet of the third shroud 51 passes through the nacelle cover 1 and connects to the outside of the compartment 11. The air inlet of the third shroud 51 is connected to the compartment 11 through the third fan 52. The third fan 52 is used to force the clean air in the compartment 11 to be discharged to the outside of the compartment 11 through the third shroud 51.

[0079] It should be noted that offshore wind turbine doubly fed induction generators include slip rings. The slip rings use a design where carbon brushes contact copper rings. The carbon brushes will gradually wear down during the friction process, producing carbon powder residue.

[0080] In this embodiment, the third hood 51 is installed outside the electric slip ring, isolating its operating space from the compartment 11. The air outlet of the third hood 51 directly penetrates the wall of the engine room cover 1 and communicates with the marine environment outside the compartment 11. The third fan 52 (usually a centrifugal fan) is installed at the air inlet of the third hood 51. It serves as a power source to directly exhaust clean air from the compartment 11 to the outside of the compartment 11 through the third hood 51.

[0081] Thus, when the electric slip ring is running, the third fan 52 starts synchronously. The operation of the third fan 52 generates negative pressure, which draws clean air from inside the chamber 11 into the third hood 51 through the air inlet. The drawn-in air flows through the high-speed rotating electric slip ring, carrying away the heat generated by the electric slip ring and blowing away the carbon powder generated by the wear of the electric slip ring. Under the forced drive of the fan, the hot air carrying the carbon powder is directly discharged to the outside environment through the air outlet of the third hood 51.

[0082] In this embodiment, the cooling and carbon removal of the electric slip ring are linked. The third fan 52 forces clean air to exchange heat with the electric slip ring, ensuring that the operating temperature of the electric slip ring is within a reasonable range and meeting the heat dissipation requirements of the electric slip ring. At the same time, the air directly exhausts the carbon powder to the outside of the cabin to prevent contamination of the internal components.

[0083] Based on the above embodiments, as a further preferred embodiment, the third fan 52 is communicatively connected to the fresh air supply module 2 through the control unit. The control unit is used to control the fresh air supply module 2 to increase the air supply volume when the third fan 52 is started, so as to maintain the micro-positive pressure environment of the chamber 11.

[0084] In one specific embodiment, the control unit acquires the operating status signal of the third fan 52 in real time (such as start / stop command feedback, operating current or speed signal). When the third fan 52 is detected to be starting, the clean air in the chamber 11 is introduced into the third hood 51 and discharged, that is, the air volume in the chamber is lost, and the pressure in the chamber 11 will decrease to be lower than the external air pressure. In order to maintain the micro-positive pressure environment of the chamber 11, the control unit calculates the increase in fresh air supply volume required to maintain the original set positive pressure based on the speed of the third fan 52, and then sends a precise control command to the fresh air supply module 2 (specifically its fan, such as a variable frequency centrifugal fan) to increase the air supply volume of the fresh air supply module 2, and its incremental value is at least equal to or slightly greater than the exhaust volume of the third fan 52, so as to maintain the micro-positive pressure environment of the chamber 11.

[0085] In another specific embodiment, the control unit can also control the air supply volume of the fresh air supply module 2 by controlling the pressure signal based on the signal from the pressure sensor inside the receiving chamber 11. For the specific control method, please refer to the above description of the precise maintenance of the micro-positive pressure environment inside the chamber, which will not be repeated here. By monitoring the deviation between the real-time pressure value and the preset positive pressure threshold, the fresh air volume can also be dynamically adjusted to ensure pressure stability.

[0086] When the third fan 52 stops, the control unit will also receive a signal and control the fresh air supply module 2 to reduce the air volume accordingly, restoring it to the level required to maintain positive pressure, thus avoiding energy waste.

[0087] In this embodiment, the third fan 52 and the fresh air supply module 2 are linked and controlled to ensure that the micro-positive pressure environment inside the chamber remains stable when the electric slip ring is running, so as to effectively exhaust the hot air of carbon powder while still effectively preventing the external salt spray from entering the chamber 11.

[0088] Based on the above embodiments, as a further preferred option, please refer to... Figure 4 The third hood 51 includes an electric slip ring housing and an exhaust pipe. The electric slip ring housing is installed around the electric slip ring. The first port of the electric slip ring housing is equipped with a third fan 52, and the second port is connected to the first port of the exhaust pipe. An electric slip ring exhaust valve 53 is installed at this connection. The second port of the exhaust pipe passes through the cabin hood 1 and extends out of the cabin 11.

[0089] In this embodiment, the slip ring housing completely encloses the slip ring, forming a sealed chamber to prevent toner diffusion. The exhaust duct, serving as a channel connecting the slip ring housing to the outside of the chamber, can directionally guide and isolate the hot air carrying toner, preventing it from contacting any other components inside the chamber and allowing it to be directly exhausted to the outside.

[0090] By adjusting the opening of the electric slip ring exhaust valve 53, the cooling exhaust volume of the electric slip ring can be independently and precisely adjusted. Preferably, the electric slip ring exhaust valve 53 is communicatively connected to the control unit, which controls the opening of the electric slip ring exhaust valve 53 based on the signal from the temperature sensor installed on the electric slip ring. Since the temperature of the electric slip ring is related to the toner production rate—that is, increased temperature may lead to accelerated carbon brush wear and increased toner production—the control unit proportionally adjusts the opening of the electric slip ring exhaust valve 53 (e.g., the higher the temperature, the larger the opening) to optimize exhaust efficiency.

[0091] When the electric slip ring stops working, the electric slip ring exhaust valve 53 can be completely closed, which not only saves energy consumption of the third fan 52, but also blocks the connection with the outside environment through the exhaust pipe, avoids backflow of high salt spray and high humidity air from outside the cabin, and enhances the airtightness of the cabin 11.

[0092] Regarding the specific settings of the fresh air supply module 2, as a further preferred option based on the above embodiments, please refer to... Figure 2 and Figure 8 The fresh air supply module 2 includes a fourth hood 21, a salt spray filter 23, and a fourth fan 24. The air inlet of the fourth hood 21 passes through the bottom of the nacelle cover 1 and connects to the outside of the compartment 11. The salt spray filter 23 and the fourth fan 24 are arranged sequentially inside the fourth hood 21 along the air inlet direction. The fourth fan 24 is used to discharge the filtered clean air from the air outlet of the fourth hood 21 and to blow the gearbox body 8 contained in the gearbox in a directional manner.

[0093] In this embodiment, the air inlet of the fourth hood 21 penetrates the bottom of the nacelle cover 1 and connects to the outside of the compartment 11. This design effectively prevents rainwater from flowing back into the fourth hood 21 and damaging its internal components, thereby improving the safety and reliability of the system operation. Inside the fourth hood 21, a salt spray filter 23 and a fourth fan 24 (typically a stable centrifugal fan) are arranged along the airflow direction (i.e., from bottom to top). This ensures that the air flowing through the fan is filtered clean air, thus avoiding corrosion of the fan impeller, motor, and other components by salt spray and extending their service life.

[0094] In addition, the air outlet of the fourth hood 21 is positioned facing the gearbox body 8 to ensure that the discharged clean air is directed to sweep the surface of the gearbox body 8 (i.e., the gearbox housing).

[0095] Regarding the specific configuration of the salt spray filter 23, based on the above embodiments, as a further preferred embodiment, the salt spray filter 23 includes a filter frame 231 and two sets of filter cotton 232. The filter frame 231 is mounted on a sliding rail inside the fourth hood 21, dividing the interior of the fourth hood 21 into a lower air duct and an upper air duct that accommodates the fourth fan 24. The two sets of filter cotton 232 are spaced apart along the vertical air intake direction on the filter frame 231, forming an intermediate air duct 233 for air circulation between them. The lower end of the filter frame 231 is provided with a filter air inlet connecting the lower air duct and the intermediate air duct 233, and the upper end of the filter frame 231 is provided with a filter air outlet connecting the upper air duct at a position directly above each set of filter cotton 232. The side wall of the fourth hood 21 has an inspection window at a position directly opposite the intermediate air duct 233, and the inspection window is covered with an openable and closable sealing window cover 234.

[0096] Specifically, the filter frame 231 has slide rails on both sides, which are installed on the mounting rails on the inner wall of the fourth hood 21, allowing the salt spray filter 23 to be removed or installed from the fourth hood 21 by pulling it out. When the filter frame 231 is installed in place, it divides the inner cavity of the fourth hood 21 into two parts, namely the upper air duct and the lower air duct. The lower air duct is located below the salt spray filter 23 and is connected to the air inlet of the fourth hood 21. The air inside is filled with unfiltered outside air. The upper air duct is located above the salt spray filter 23 and houses the fourth fan 24. The air inside is filled with filtered clean air.

[0097] Inside the filter frame 231, two sets of filter cotton 232 are spaced apart along the vertical air intake direction, forming an intermediate air duct 233 between the two sets of filter cotton 232. A filter air inlet is provided at the lower end of the filter frame 231, which connects the lower air duct and the intermediate air duct 233. A filter air outlet is provided at the upper end of the filter frame 231, directly above each set of filter cotton 232, which connects the clean air outside the filter cotton 232 with the upper air duct.

[0098] Therefore, please refer to the following: Figure 9 Outside air enters the lower duct through the bottom of the fourth hood 21 and then enters the middle duct 233 through the filter inlet at the lower end of the filter frame 231. Subsequently, the air flows simultaneously to both sides, penetrating both sets of filter cotton 232. Salt mist is intercepted by the filter cotton 232, and clean air reaches the outside of the filter cotton 232 and converges upwards, entering the upper duct through the corresponding two filter outlets at the upper end of the filter frame 231. Finally, it is pressurized and sent out by the fourth fan 24. This design allows the two sets of filter cotton 232 to work in parallel. Under the same airflow, the air velocity through the filter cotton 232 is reduced, thus reducing filtration resistance. This not only reduces fan energy consumption but also facilitates finer filtration of particulate matter and extends the service life of the filter cotton 232.

[0099] To facilitate inspection without disassembling the entire module, please refer to... Figure 8 and Figure 9 The fourth air hood 21 has a maintenance window on its side wall opposite the central air duct 233. The maintenance window is covered by an openable and closable sealed cover 234. The sealed cover 234 can be installed on the fourth air hood 21 via hinges or screws and has a sealing strip to ensure airtightness when closed. This allows personnel to open the sealed cover 234 to directly observe the condition of the central air duct 233 and easily check the degree of contamination of the filter cotton 232 on both sides. If the contamination level is high, the filter cotton 232 can be replaced directly through the maintenance window.

[0100] Based on the above embodiments, as a further preferred option, please refer to... Figure 8 and Figure 9 A gas-liquid separator 22 is also provided at the air inlet of the fourth hood 21.

[0101] Before entering the fourth hood 21, the humid outside air is first filtered out by the gas-liquid separator 22. This prevents the filter cotton 232 of the salt spray filter 23 from getting wet and becoming clogged or damaged, ensuring the stability of the filtration and ventilation of the salt spray filter 23. On the other hand, it reduces the humidity of the air entering the cabin 11, reduces the risk of condensation, and ensures the safe and stable operation of the unit.

[0102] Based on the above embodiments, as a further preferred option, please refer to... Figure 2 , Figure 3 and Figure 5 The first shroud 31 is used to cover the gearbox radiator included in the gearbox. The air inlet of the first shroud 31 penetrates the bottom of the nacelle cover 1 and the air outlet penetrates the rear of the nacelle cover 1. The gearbox air-cooling module 3 also includes a first fan installed inside the first shroud 31, which is used to draw air from the bottom of the nacelle cover 1 and discharge it from the rear of the nacelle cover 1.

[0103] It should be noted that the gearbox radiator is connected to the lubrication circuit of the gearbox body 8 via oil cooling pipe 9. High-temperature lubricating oil flows out from the oil outlet of the gearbox body 8 and is pumped to the oil inlet of the gearbox radiator through the oil cooling pipe 9. The lubricating oil flows inside the gearbox radiator (usually a finned oil cooler), transferring the heat it carries to the fins. The cooled lubricating oil flows out from the oil outlet of the gearbox radiator and then flows back to the oil inlet of the gearbox body 8 through the oil cooling pipe 9 to re-lubricate and cool the gears and bearings in the gearbox body 8.

[0104] In this embodiment, the first shroud 31 is installed on the gearbox radiator to form a first air duct that is isolated from the cabin 11. The air inlet of the first shroud 31 penetrates the bottom of the cabin cover 1 and is directly connected to the outside environment. This air inlet can prevent rainwater from flowing back into the first shroud 31 and corroding the fan inside. The air outlet of the first shroud 31 penetrates the rear of the cabin cover 1 and leads directly to the outside. The first fan is installed inside the first shroud 31. The first fan is preferably an axial flow fan with a large flow rate and low air pressure.

[0105] Thus, when the gearbox is running, the heat of its lubricating oil is transferred to the gearbox radiator. At the same time, the first fan starts and generates negative pressure inside the first fan shroud 31, drawing outside air into the first fan shroud 31 from the air inlet at the bottom of the nacelle cover 1. The drawn-in air flows over the dense fins of the gearbox radiator and undergoes efficient heat exchange with the fins. Under the forced drive of the first fan, the heated air is directly discharged outside the nacelle from the air outlet at the rear of the nacelle cover 1, completing the air cooling of the gearbox radiator.

[0106] As described above, in this embodiment, the first shroud 31 and the first fan work together to form a high-speed airflow, which blows away the heat from the surface of the gearbox radiator fins, thereby indirectly and efficiently cooling the lubricating oil inside the gearbox body 8 and removing most of the heat from the gearbox. At the same time, the fresh air supply module 2 blows away the surface of the gearbox body 8 to directly remove the heat conducted from the inside of the gearbox body 8 to its surface, thereby removing the residual heat from the gearbox and significantly enhancing the cooling effect of the gearbox.

[0107] Based on the above embodiments, as a further preferred option, please refer to... Figure 2 , Figure 3 and Figure 7 The second shroud 41 is used to cover the generator radiator included in the generator; the generator air-cooling module 4 also includes a second fan 42 disposed in the second shroud 41, which is used to draw in air from outside the compartment 11, flow through the second shroud 41, and force it out of the compartment 11.

[0108] It should be noted that the generator radiator is typically a series of closely spaced cooling fins on the generator body 10, or a cooling backpack on the outer casing of the generator body 10, with cooling air ducts embedded inside. Thus, the generator radiator primarily serves to increase the contact area between the generator and the outside air for efficient convective heat exchange.

[0109] In this embodiment, the second shroud 41 matches the shape of the generator radiator and covers the generator radiator. For example, the second shroud 41 encloses the heat dissipation fin area of ​​the generator body 10. A second fan 42 (usually a centrifugal fan) is installed inside the second shroud 41. When the second fan 42 is started, a negative pressure is generated inside the second shroud 41, drawing outside air into the shroud (i.e., the second air duct) through the first air inlet 411. The air flows through all the fins of the generator radiator for efficient heat exchange. Driven by the second fan 42, the heated air is directly discharged back to the outside environment through the air outlet of the second shroud 41.

[0110] This design, where the second shroud 41 covers the heat dissipation fin area outside the generator body 10, effectively prevents high-salt-spray, high-humidity marine air from contacting the internal components of the generator body 10 (such as the stator, rotor windings, or core) while meeting the generator's heat dissipation requirements, thus ensuring reliable generator operation. Furthermore, the second air duct is isolated from the compartment 11, effectively preventing high-salt-spray, high-humidity marine air from entering the compartment 11 and corroding the generator surface and other core components.

[0111] Based on the above embodiments, as a further preferred option, please refer to... Figure 3 The first air inlet 411 of the second wind cover 41 is a flared structure, and its large-diameter end faces out of the cabin 11 and is inclined downward.

[0112] In this embodiment, the first air inlet 411 of the second shroud 41 is a flared structure, which is a gradually expanding cone shape. Its large-diameter end (i.e., the inlet end) faces the outside of the compartment 11, and its small-diameter end is smoothly connected to the main body of the second shroud 41. This flared structure can gently guide the airflow, reduce local eddies caused by abrupt changes in cross-section, make the air diffuse more evenly, and improve the cooling efficiency of the generator.

[0113] In addition, the large-diameter end of the flared structure faces downwards, which can effectively prevent rainwater from flowing back into the second hood 41 and causing damage to its built-in second fan 42, thereby improving the safety and reliability of the system operation.

[0114] Based on the above embodiments, as a further preferred embodiment, the surface of at least one of the second fan 42 of the generator air-cooled module 4, the first fan of the gearbox air-cooled module 3, and the inner cavity surface of the first shroud 31 and the second shroud 41 has an anti-corrosion coating.

[0115] In one specific embodiment, the anti-corrosion coating is formed by processing materials and / or processes that meet the C5-H anti-corrosion grade requirements. It may be, but is not limited to, a polyurea protective coating with a thickness of not less than 0.5 mm, which can enhance the system's corrosion resistance in high-salt spray environments at sea and extend the service life of the equipment.

[0116] Based on the above embodiments, as a further preferred embodiment, the air outlets of the first shroud 31, the second shroud 41, the third shroud 51, and the fourth shroud 21 are all connected to flexible ducts. There may be alignment deviations between the air outlets of each shroud and the openings on the nacelle cover 1. Using flexible ducts (such as corrugated metal pipes) during installation allows for a certain degree of displacement and angular deflection, enabling better alignment as they extend through the openings on the nacelle cover 1 to the outside of the compartment 11, thus improving installation convenience. Furthermore, when hot air (such as air exhausted from the gearbox radiator) flows through, the flexible ducts have good elasticity, absorbing the pipe expansion and contraction stress caused by temperature changes, preventing sealing failure or structural damage due to thermal expansion and contraction.

[0117] This invention also provides a doubly-fed induction generator for offshore wind power, please refer to [reference needed]. Figure 1 and Figure 2 This includes the nacelle system, main shaft assembly 6, tower, gearbox, generator, and defrosting machine 12 of the offshore wind turbine doubly fed by the above embodiments.

[0118] The main spindle assembly 6 is connected to the head of the nacelle cover 1 via a flange, and a first seal is provided between the flange and the nacelle cover 1; the tower is connected to the bottom of the nacelle cover 1 via a yaw drive system 7, and a second seal is provided at the connection between the tower and the nacelle cover 1; the gearbox includes a gearbox body 8 and a gearbox radiator both located in the compartment 11, the input end of the gearbox body 8 is connected to the output end of the main spindle assembly 6, the gearbox radiator is located at the rear of the compartment 11 and is connected to the lubrication circuit of the gearbox body 8 via an oil cooling pipe 9; the generator includes a generator body 10 located in the compartment 11 and a generator radiator located on the generator body 10, the input end of the generator body 10 is connected to the output end of the gearbox, and the output end of the generator body 10 is connected to an electric slip ring; the defroster 12 is located in the compartment 11.

[0119] The offshore wind turbine doubly fed induction generator unit of this embodiment has the following main advantages:

[0120] The fully air-cooled modular design eliminates the need for high-cost external components and complex piping in traditional water-cooled designs, while also avoiding maintenance needs such as improper antifreeze ratios and leaks, thus reducing later maintenance costs.

[0121] By utilizing the micro-positive pressure and isolation duct design of the nacelle system, the core components of the unit (such as the gearbox and generator) can be effectively isolated from the high salt spray and high humidity of the sea air during operation, thereby improving the long-term operational reliability and lifespan of the entire unit.

[0122] Under high load or high temperature conditions, the gearbox and generator will not reduce load due to overheating, thus ensuring stable operation of the whole machine.

[0123] The first seal at the main shaft flange and the second seal at the tower connection ensure that compartment 11 is airtight, effectively preventing the intrusion of salt spray, moisture, and other external substances. It should be noted that the first and second seals can be, but are not limited to, seals made of brushes or sealing rings.

[0124] The gearbox radiator is located at the rear of compartment 11 and is connected to the gearbox body 8 via oil cooling pipe 9, so as to make reasonable use of the internal space of the whole machine and ensure the feasibility of the aforementioned gearbox heat dissipation scheme (i.e., the combined scheme of indirect cooling of the lubricating oil in the gearbox and direct cooling of the gearbox surface).

[0125] The defrosting machine 12 can remove water mist in the compartment 11. Working in conjunction with the fresh air supply module 2, it can effectively ensure that the electrical equipment in the entire unit is in a dry and clean operating environment, thereby significantly reducing the risk of electrical failure and improving the safety and stability of the entire unit's operation.

[0126] More preferably, the offshore wind turbine also includes a control cabinet 13 located in the cabin 11, which can accommodate the control unit of the nacelle system to facilitate its connection with the various modules and sensors in the cabin 11. For example, it can acquire the environmental parameters (such as pressure or temperature) in the cabin in real time, and instruct the fresh air supply module 2 and various air-cooling modules to work together according to these parameters, thereby realizing precise and automated heat dissipation of the unit.

[0127] The present invention also provides a heat dissipation method applied to the nacelle system of the offshore wind turbine doubly-fed induction generator disclosed in the above embodiments. The heat dissipation method includes:

[0128] Step 1: Control the operation of the fresh air supply module 2 to establish a slightly positive pressure environment in the chamber 11, and perform directional blowing to assist heat dissipation on the gearbox body 8 of the gearbox.

[0129] This step establishes a slightly positive pressure environment and activates the gearbox to assist in heat dissipation. Specifically, the fourth fan 24 is activated to draw air in from outside the chamber. After being purified by the gas-liquid separator 22 and the salt spray filter 23, clean and dry air is continuously introduced into the sealed chamber 11. By adjusting the speed of the fourth fan 24, the airflow into the chamber is made slightly greater than the total amount of air that could potentially leak or be exhausted, thereby establishing and maintaining a slightly positive pressure environment within the chamber to effectively prevent the intrusion of external salt spray moisture. At the same time, the exhaust air from the fresh air supply module 2 continuously blows across the surface of the gearbox body 8. This airflow carries away the heat from the surface of the gearbox body, assisting in heat dissipation.

[0130] Step 2: Start the gearbox air-cooling module 3 and the generator air-cooling module 4 to drive the outside air through their respective air ducts, which are isolated from the cabin 11, to perform basic air-cooling on the gearbox radiator and the generator.

[0131] This step initiates the basic air-cooled heat dissipation mode. While maintaining the operation of the fresh air supply module 2, or after a certain period of time, the gearbox air-cooling module 3 and the generator air-cooling module 4 are activated. Specifically, for the gearbox air-cooling module 3: the first fan inside the first shroud 31 is activated, driving outside air to be drawn in from the bottom air inlet of the nacelle cover 1, flowing through the interior of the first shroud 31 covering the gearbox radiator, exchanging heat with the radiator fins, and then the hot air is directly discharged outside the nacelle from the rear air outlet of the nacelle cover 1, forming a first air duct isolated from the compartment 11. For the generator air-cooling module 4: the second fan 42 inside the second shroud 41 is activated, driving outside air to be drawn in through the first air inlet 411 (such as a flared mouth) of the second shroud 41, flowing through the interior of the second shroud 41 covering the generator radiator, cooling the generator, and then the hot air is directly discharged outside the nacelle from the air outlet, forming a second air duct isolated from the compartment 11. This step provides independent basic air-cooled heat dissipation for the gearbox and generator, using outside air to directly cool their core heat-generating components (radiators), meeting the heat dissipation requirements of the unit under normal operating conditions. In particular, during the air-cooled heat dissipation process, it effectively prevents high salt spray and high humidity marine air from entering the cabin 11.

[0132] Step 3: Obtain the generator's operating temperature in real time, and control the air supply volume of the fresh air supply module 2 and the opening degree of the air valve 43 according to the operating temperature to enhance the generator's air cooling heat dissipation.

[0133] This step activates the enhanced air-cooling mode. While the generator is operating under basic air-cooling conditions, the temperature sensor on the generator acquires the generator's operating temperature in real time. Based on the operating temperature, the speed of the fourth fan 24 in the fresh air supply module 2 and the opening of the air valve 43 on the second shroud 41 are dynamically adjusted to achieve enhanced air-cooling of the generator.

[0134] The specific steps for controlling the air volume of the fresh air supply module 2 and the opening degree of the damper 43 according to the operating temperature are as follows:

[0135] A first temperature threshold T1 and a second temperature threshold T2 can be preset in the control unit, where T1>T2.

[0136] When the generator operating temperature is ≤T2, it indicates that the generator operating temperature is normal, and the basic cooling mode can effectively dissipate heat. The control unit only needs to make the generator air-cooling module 4 operate independently (such as starting its built-in second fan 42) and keep the air valve 43 in the closed state. Outside air enters the second air shroud 41 only through the first air inlet 411, cools the generator, and is discharged from the air outlet, forming an isolated second air duct. This mode ensures the generator's basic heat dissipation requirements and corrosion protection.

[0137] When T2 < generator operating temperature ≤ T1, it indicates that the generator operating temperature is relatively high, which is the first enhanced cooling mode. That is, only the air valve 43 needs to be adjusted to effectively dissipate heat. The control unit adjusts the opening of the air valve 43 proportionally (for example, the higher the temperature, the larger the opening), introducing an appropriate amount of clean air from the compartment into the second air duct to increase the air intake of the second air duct and enhance the generator's air-cooled heat dissipation.

[0138] When the generator operating temperature exceeds T1, it indicates that the generator operating temperature is too high. This triggers the second enhanced cooling mode, which requires simultaneous adjustment of the airflow from both the damper 43 and the fresh air supply module 2 to achieve effective heat dissipation. The control unit controls the damper 43 to open to its maximum extent and controls the fresh air supply module 2 to increase the airflow, providing a sufficient and cooled clean air source to enhance the generator's cooling capacity to the maximum extent.

[0139] This step allows for precise adjustment of the generator's cooling mode based on its real-time operating temperature, ensuring that the generator remains within its normal operating temperature range while minimizing unnecessary energy consumption for heat dissipation.

[0140] Based on the above embodiments, as a further preferred embodiment, the heat dissipation method further includes:

[0141] The electric slip ring air-cooling module is activated to directly exhaust clean air from the chamber 11 to the outside of the chamber for air cooling of the electric slip ring. At the same time, the fresh air supply module 2 is controlled to increase the air supply volume to compensate for the pressure loss in the chamber caused by the exhaust of the electric slip ring air-cooling module and maintain a slightly positive pressure environment in the chamber 11.

[0142] Specifically, upon receiving a command to cool the slip ring or remove toner, the third fan 52 inside the third hood 51 is activated. Clean air inside the chamber 11 is drawn into the third hood 51 through the air inlet, flows through the high-speed rotating slip ring, carrying away the heat generated by the slip ring and simultaneously blowing away the toner produced by slip ring wear. Under the forced drive of the fan, the hot air carrying toner is directly discharged to the outside environment through the air outlet of the third hood 51, thus simultaneously achieving slip ring cooling and toner removal. At the same time, based on the rotational speed of the third fan 52 or the chamber pressure fed back by the current pressure sensor, the increased fresh air volume required to maintain the original positive pressure is calculated. This increased air volume is converted into the corresponding rotational speed of the fourth fan 24, and then a precise control command is sent to the fourth fan 24 to maintain a slightly positive pressure environment in the chamber 11. This step ensures that the slightly positive pressure environment inside the chamber remains stable during slip ring operation, thus effectively removing hot air containing toner while still effectively preventing external salt mist from entering the chamber 11.

[0143] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0144] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0145] The foregoing has provided a detailed description of an offshore wind turbine doubly-fed induction generator (DFIG) and its nacelle system and heat dissipation method provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the invention. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. An offshore wind power double-fed unit nacelle system, characterized in that, The utility model relates to a kind of air cooling module for the engine room of the ship, including: Engine room cover (1), inside the closed cabin (11); Fresh air supply module (2), it is located in the cabin (11), the air inlet end of the fresh air supply module (2) is communicated with the cabin (11) outside through the engine room cover (1), and the air outlet end is communicated with the cabin (11), for supplying filtered clean air to the cabin (11), to establish and maintain the slightly positive pressure environment of the cabin (11), and to purge cooling gearbox; Gearbox air cooling module (3), including the first wind cover (31) for covering the heat dissipation part of the gearbox, the air inlet and the air outlet of the first wind cover (31) are communicated with the cabin (11) outside through the engine room cover (1), to form the first air duct isolated with the cabin (11); Generator air cooling module (4), including the second wind cover (41) for covering the heat dissipation part of the generator, the first air inlet (411) and the air outlet of the second wind cover (41) are communicated with the cabin (11) outside through the engine room cover (1), to form the second air duct isolated with the cabin (11), the second air inlet (412) of the second wind cover (41) is located in the cabin (11) and is provided with air valve (43), and the air valve (43) can introduce clean air in the cabin (11) into the second air duct when being opened.

2. The offshore wind power double-fed machine package system according to claim 1, characterized in that, The fresh air supply module (2), the gearbox air cooling module (3) and the generator air cooling module (4) are all connected with control unit in communication; The control unit is used for receiving the signal of pressure sensor arranged in the cabin (11) in real time, and the air supply amount of the fresh air supply module (2) is controlled according to the pressure signal, to maintain the slightly positive pressure environment of the cabin (11); The control unit is used for receiving the signal of temperature sensor arranged on the generator in real time, and the air supply amount of the fresh air supply module (2) and the opening degree of the air valve (43) are controlled according to the temperature signal.

3. The offshore wind power double-fed machine package system according to claim 1, characterized in that, It also includes electric slip ring air cooling module (5), the electric slip ring air cooling module (5) includes third fan (52) and the third wind cover (51) for covering the electric slip ring, the air outlet of the third wind cover (51) is communicated with the cabin (11) outside through the engine room cover (1), and the air inlet of the third wind cover (51) is communicated with the cabin (11) by the third fan (52), and the third fan (52) is used to directly discharge clean air in the cabin (11) to the cabin (11) outside through the third wind cover (51).

4. The offshore wind power double-fed machine package system according to claim 3, characterized in that, The third fan (52) is connected with the fresh air supply module (2) in communication through control unit, and the control unit is used to control the fresh air supply module (2) to increase air supply amount when the third fan (52) is started, to maintain the slightly positive pressure environment of the cabin (11).

5. The offshore wind power double-fed machine package system according to claim 1, characterized in that, The fresh air supply module (2) comprises a fourth air cover (21), a salt mist filter (23) and a fourth fan (24), an air inlet of the fourth air cover (21) penetrates through the bottom of the cabin cover (1) to communicate with the cabin (11) outside, the salt mist filter (23) and the fourth fan (24) are sequentially arranged in the fourth air cover (21) along the air inlet direction, and the fourth fan (24) is used for discharging filtered clean air from an air outlet of the fourth air cover (21) and directionally blowing the gear box body (8) contained in the gear box.

6. The offshore wind power double-fed machine package system according to claim 5, characterized in that, The salt mist filter (23) comprises a filter frame (231) and two groups of filter cotton (232), the filter frame (231) is arranged on a mounting slide rail in the fourth air cover (21) and separates the inside of the fourth air cover (21) into an air duct below and an air duct above containing the fourth fan (24), and the two groups of filter cotton (232) are arranged in the filter frame (231) along the vertical air inlet direction and form an intermediate air duct (233) for air flow between them. The lower end of the filter frame (231) is provided with a filter air inlet communicating the lower air duct and the intermediate air duct (233), and the upper end of the filter frame (231) is provided with a filter air outlet communicating the upper air duct above each group of filter cotton (232). The side wall of the fourth air cover (21) is provided with an inspection window at a position opposite to the intermediate air duct (233), and a sealable inspection window cover (234) is arranged on the inspection window.

7. The offshore wind power double-fed machine package system according to claim 5, characterized in that, The air inlet of the fourth air cover (21) is further provided with an air-liquid separator (22).

8. The offshore wind power double-fed machine package system according to claim 1, characterized in that, The first air cover (31) is used for covering the gear box radiator contained in the gear box, the air inlet of the first air cover (31) penetrates through the bottom of the cabin cover (1), and the air outlet penetrates through the tail of the cabin cover (1). The gear box air cooling module (3) further comprises a first fan arranged in the first air cover (31) and used for sucking air from the bottom of the cabin cover (1) and discharging the air from the tail of the cabin cover (1).

9. The offshore wind power double-fed machine package system according to claim 1, characterized in that, The second air cover (41) is used for covering the generator radiator contained in the generator. The generator air cooling module (4) further comprises a second fan (42) arranged in the second air cover (41) and used for sucking air outside the cabin (11) to flow through the second air cover (41) and forcibly discharging the air to the outside of the cabin (11).

10. The offshore wind power double-fed machine package system according to claim 1, characterized in that, The first air inlet (411) of the second air cover (41) is in a horn structure, and the large-diameter end of the first air inlet (411) is inclined downward and faces the outside of the cabin (11).

11. An offshore wind power double-fed unit, characterized by The offshore wind power double-fed machine set cabin system comprises: The offshore wind power double-fed machine set cabin system according to any one of claims 1 to 10; A main shaft assembly (6) is connected to the head of the cabin cover (1) through a flange, and a first sealing element is arranged between the flange and the cabin cover (1); A tower is connected to the bottom of the cabin cover (1) through a yaw driving system (7), and a second sealing element is arranged at the connection between the tower and the cabin cover (1); The offshore wind power double-fed machine set cabin system according to any one of claims 1 to 10; The gearbox comprises a gearbox body (8) and a gearbox radiator, both of which are arranged in the cabin (11), the input end of the gearbox body (8) is connected to the output end of the main shaft assembly (6), and the gearbox radiator is arranged at the tail of the cabin (11) and is connected to the lubrication circuit of the gearbox body (8) through an oil cooling pipeline (9); The generator comprises a generator body (10) arranged in the cabin (11) and a generator radiator arranged on the generator body (10), the input end of the generator body (10) is connected to the output end of the gearbox, and the output end of the generator body (10) is connected to an electric slip ring; A defroster (12) is arranged in the cabin (11).

12. A heat dissipation method, characterized by, The heat dissipation method is applied to the offshore wind power double-fed machine set cabin system according to any one of claims 1 to 10, and the heat dissipation method comprises: Controlling the fresh air supply module to run, establishing a micro-positive pressure environment in the cabin, and performing directional purging auxiliary heat dissipation on the gearbox body of the gearbox; Starting the gearbox air cooling module and the generator air cooling module, driving the outside air to flow through the air ducts formed respectively and isolated from the cabin, and performing basic air cooling heat dissipation on the gearbox radiator and the generator of the gearbox; Real-time acquisition of the operating temperature of the generator, and control of the air supply amount of the fresh air supply module and the opening degree of the air valve according to the operating temperature to perform enhanced air cooling heat dissipation on the generator.

13. The heat dissipation method according to claim 12, wherein, The heat dissipation method further comprises: Starting the electric slip ring air cooling module, directly discharging the clean air in the cabin to the outside of the cabin to perform air cooling heat dissipation on the electric slip ring; At the same time, controlling the fresh air supply module to increase the air supply amount to compensate for the loss of cabin pressure caused by the air exhaust of the electric slip ring air cooling module, and maintaining the micro-positive pressure environment of the cabin.

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