Motor cooling system based on magneto-caloric phase transition coupling and cooling method thereof

Abstract

The application discloses a motor cooling system and a cooling method based on a magneto-caloric phase transition coupling effect, and comprises a solid cooling layer arranged on the outer surface of a motor stator winding, wherein the solid cooling layer comprises, from inside to outside, a heat conduction interface layer, a magneto-caloric material layer, a phase change energy storage layer and an adiabatic shell layer. A magnetic field modulation assembly is arranged outside the solid cooling layer and forms a non-contact air gap with the magneto-caloric material layer, and the magnetic field modulation assembly is driven to rotate around the solid cooling layer by a driving mechanism; the magnetic field intensity and direction acting on the magneto-caloric material layer through the air gap are periodically changed, so that the magneto-caloric material layer undergoes magnetization and demagnetization processes, and temperature rise and temperature drop are alternately changed; a continuous solid heat conduction path is formed between the magneto-caloric material layer and the phase change energy storage layer, and the adiabatic shell layer is used for reducing heat exchange between the system and the external environment.

Description

Technical Field

[0001] This invention belongs to the field of wind power generation technology, and specifically relates to a cooling system and control method for a magnetocaloric phase change coupling effect. Background Technology

[0002] As a clean energy source, wind power is increasingly accounting for a larger share of the global energy mix. With the growing global demand for renewable energy, wind power is playing an increasingly important role in reducing carbon emissions and dependence on traditional fossil fuels. To meet the ever-increasing electricity demand, the capacity of individual wind turbines is constantly increasing, making heat dissipation a more prominent issue. An efficient cooling system is crucial for the reliable operation and long-term stability of wind turbines; therefore, the research and development of cooling technology has become an important topic in the field of wind power.

[0003] Currently, mainstream wind turbine cooling systems are mainly classified into the following categories: air cooling systems, liquid cooling systems, and evaporative cooling systems. However, liquid cooling systems are prone to leakage under long-term vibration conditions, requiring regular coolant replacement, pipe cleaning, and pump and valve maintenance. Water cooling systems are prone to freezing in cold regions and boiling in high-temperature regions. The energy consumption of auxiliary equipment such as water pumps and fans accounts for a relatively small percentage of power generation. In addition, there are risks associated with numerous moving mechanical parts and a high failure rate. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a motor cooling system and method based on magnetocaloric phase change coupling. The aim is to shift thermodynamic entropy control from macroscopic fluids to microscopic electron spins, precisely regulate the intrinsic order of materials through magnetic fields, and thereby control their thermodynamic state.

[0005] The first aspect of the present invention provides a motor cooling system based on magnetocaloric phase change coupling. The system includes: a solid cooling layer disposed on the outer surface of the motor stator winding, wherein the solid cooling layer comprises, from the inside to the outside, a thermally conductive interface layer, a magnetocaloric material layer, a phase change energy storage layer, and a thermally insulating outer shell layer.

[0006] A magnetic field modulation component is disposed on the outside of the solid cooling layer. The magnetic field modulation component includes multiple magnetic field units arranged circumferentially to form a rotating magnetic field. A non-contact air gap is formed between the magnetic field modulation component and the magnetocaloric material layer.

[0007] The driving mechanism includes a motor and a transmission structure connected to the magnetic field modulation component, used to drive the magnetic field modulation component to rotate around the solid cooling layer; causing the intensity and / or direction of the magnetic field acting on the magnetocaloric material layer through the air gap to change periodically, thereby causing the magnetocaloric material layer to undergo magnetization and demagnetization processes, resulting in alternating changes in temperature rise and temperature fall; a continuous solid-state heat conduction path is formed between the magnetocaloric material layer and the phase change energy storage layer, and the heat insulation shell layer is used to reduce heat exchange between the system and the external environment.

[0008] According to one embodiment of the present invention, the thermally conductive interface layer is an insulating thermally conductive material layer, so that the magnetocaloric material layer and the motor stator winding achieve surface contact and bonding.

[0009] According to one embodiment of the present invention, the magnetocaloric material layer is a continuous layered structure composed of a metal alloy or composite magnetocaloric material with magnetocaloric effect.

[0010] According to one embodiment of the present invention, the magnetization direction of the adjacent magnetic field units changes sequentially according to a preset angle.

[0011] According to one embodiment of the present invention, the magnetic field modulation component is supported on the motor end plate or housing structure by bearings and maintains a non-contact air gap with the solid cooling layer.

[0012] According to one embodiment of the present invention, the phase change energy storage layer is an encapsulated composite phase change material layer, which contains a phase change matrix material and a thermally conductive enhancement structure.

[0013] According to one embodiment of the present invention, the phase change energy storage layer is provided with a microcapsule encapsulation structure to restrict the flow of the phase change material during the solid-liquid transition process.

[0014] According to one embodiment of the present invention, the cooling system further includes a temperature acquisition unit and a control unit, wherein the control unit adjusts the operating parameters of the drive mechanism according to the temperature information acquired by the temperature acquisition unit, so as to change the magnetic field change of the magnetic field modulation component.

[0015] A second aspect of this invention provides a cooling method for a motor cooling system based on magnetocaloric phase change coupling. The method includes: disposing a solid-state cooling layer outside the motor stator windings; driving a magnetic field modulation component to rotate around the solid-state cooling layer, causing periodic changes in the strength and / or direction of the magnetic field acting on the magnetocaloric material layer; thereby causing the magnetocaloric material layer to undergo magnetization and demagnetization processes, resulting in alternating temperature increases and decreases. During demagnetization, the temperature of the magnetocaloric material layer decreases, absorbing heat from the motor. During magnetization, the temperature of the magnetocaloric material layer increases, transferring the absorbed heat to the phase change energy storage layer through a continuous solid-state heat conduction path; and the phase change energy storage layer absorbs the heat.

[0016] According to one embodiment of the present invention, the frequency of change of the magnetic field strength and / or direction generated by the magnetic field modulation component is adjusted according to the motor load or temperature change.

[0017] The technical effects achieved by this invention are as follows: By coupling the reversible changes in magnetization and demagnetization temperature of the magnetocaloric material layer with the latent heat absorption of the phase change energy storage layer, a fluidless solid-state thermal regulation cycle is formed, realizing rapid heat removal and peak suppression of the motor windings; The layered bonding structure shortens the heat transfer path and reduces the interface thermal resistance, while the phase change energy storage smooths the temperature rise caused by load fluctuations, improving temperature control stability and insulation life; Non-contact air gap magnetic coupling avoids dynamic seals and liquid circuits, reducing leakage and maintenance risks, and improving the long-term reliability and environmental adaptability of the system. Attached Figure Description

[0018] Figure 1 This is a block diagram of a motor cooling system based on magnetocaloric phase change coupling disclosed in an embodiment of the present invention; Figure 2 This is a block diagram of a solid-state cooling layer in a motor cooling system based on magnetocaloric phase change coupling, as disclosed in an embodiment of the present invention. Figure 3 This is a temperature change curve of the magnetocaloric effect working cycle disclosed in an embodiment of the present invention; Figure 4 This is a thermal response curve of the phase change material disclosed in the embodiments of the present invention; Figure 5 This is a flowchart of a cooling method for a motor cooling system based on magnetocaloric phase change coupling, as disclosed in an embodiment of the present invention. Detailed Implementation

[0019] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0020] The magnetothermal phase change coupling cooling system is directly installed on the outer surface of the generator stator winding; the rotating magnetic ring is installed outside the generator, maintaining a 3mm air gap with the generator surface, supported by the generator end plate, and driven by the motor gear installed on the top.

[0021] The present invention discloses a motor cooling system based on magnetocaloric phase change coupling, comprising: a solid cooling layer disposed on the outer surface of the motor stator winding, wherein the solid cooling layer comprises, from the inside out: a thermally conductive interface layer, a magnetocaloric material layer, a phase change energy storage layer, and a thermally insulating outer shell layer.

[0022] A magnetic field modulation component is disposed on the outside of the solid cooling layer. The magnetic field modulation component includes a magnetic field unit composed of multiple permanent magnets arranged circumferentially to form a rotating magnetic field. A non-contact air gap is formed between the magnetic field modulation component and the magnetothermal material layer.

[0023] The driving mechanism includes a motor and a transmission structure connected to the magnetic field modulation component. It drives the magnetic field modulation component to rotate around the solid-state cooling layer, causing periodic changes in the strength or direction of the magnetic field acting on the magnetocaloric material layer through the air gap. This results in magnetization and demagnetization of the magnetocaloric material layer, producing alternating temperature increases and decreases. A continuous solid-state heat conduction path is formed between the magnetocaloric material layer and the phase change energy storage layer. The insulating outer shell layer reduces heat exchange between the system and the external environment. The magnetic field unit can be a permanent magnet, an electromagnet, or other device capable of generating a magnetic field.

[0024] The magnetocaloric material layer, made of gadolinium-based alloy (such as Gd5Si2Ge2), is 1-3 mm thick and is tightly attached to the surface of the generator stator winding through a high thermal conductivity adhesive layer. The magnetocaloric material exhibits a significant magnetocaloric effect, producing a temperature change when the applied magnetic field changes.

[0025] The rotatable permanent magnet array adopts a Halbach array structure, with multiple permanent magnet units arranged in a ring, and the magnetization directions of adjacent units differ by a certain angle (preferably 45°-90°). The permanent magnet array is supported by bearings and driven to rotate by a servo motor.

[0026] The phase change material layer is a composite material of paraffin-based phase change material and graphene, with an adjustable phase change temperature within the range of 45-85℃. The material's internal structure is a honeycomb microcapsule structure, increasing the heat exchange area and preventing leakage. A thermally enhanced structure incorporates a three-dimensional graphene network within the phase change material, improving the thermal conductivity to over 15 W / m·K.

[0027] The magnetocaloric material layer and the phase change energy storage layer are directly adjacent to each other along the thickness direction, and a continuous solid-state heat conduction path is formed between them through surface contact. The continuous solid-state heat conduction path means that heat is directly transferred between the magnetocaloric material layer and the phase change energy storage layer through solid-state heat conduction, without relying on liquid or gas flow media.

[0028] A thermally conductive interface material or a thermally conductive adhesive layer is disposed between the magnetocaloric material layer and the phase change energy storage layer to enhance interface contact and reduce contact thermal resistance, enabling rapid heat transfer between the two. The thermally conductive interface material can be thermally conductive silicone grease, thermally conductive adhesive, or other materials with high thermal conductivity.

[0029] During magnetization, the temperature of the magnetocaloric material layer rises, and the heat it absorbs is transferred to the phase change energy storage layer through the continuous solid-state heat conduction path. The phase change energy storage layer absorbs heat and stores it through the phase change process, thereby reducing the temperature of the magnetocaloric material layer and providing temperature difference conditions for the subsequent demagnetization stage.

[0030] Compared to cooling methods that rely on fluid circulation, this application achieves a heat transfer path without fluid participation by constructing the continuous solid-state heat conduction path, which is beneficial to improving the structural stability of the system and reducing the risk of leakage. At the same time, it can achieve efficient heat transfer under the action of magnetocaloric effect.

[0031] The magnetocaloric material layer and the phase change energy storage layer are directly adjacent to each other along the thickness direction, forming a continuous solid-state heat conduction path between them. This allows the heat generated by the magnetocaloric material layer under the action of an alternating magnetic field to be transferred to the phase change energy storage layer, where it is absorbed and stored through a phase change process.

[0032] Instead of simply stacking the magnetocaloric material layer and the phase change energy storage layer, the two are brought into close contact in structure to form a continuous solid-state heat conduction path. This allows the heat generated by the magnetocaloric material layer during magnetization to be efficiently transferred to the phase change energy storage layer, thereby achieving the coupling between the magnetocaloric effect and the phase change energy storage process.

[0033] The temperature acquisition unit, comprised of a network of temperature sensors located at key parts of the generator, collects temperature data in real time. The magnetic field control unit, based on the temperature signal, uses a model predictive control algorithm to calculate optimal magnetic field parameters, controlling the rotation angle, speed, and dwell time of the permanent magnet array. The fault diagnosis unit monitors the system's operating status, enabling fault warnings and degraded operation.

[0034] During system operation, the intelligent control module controls the periodic rotation of the permanent magnet array based on the generator temperature and load status. In the magnetization heating phase, the permanent magnet array rotates until the magnetic field perpendicularly passes through the magnetocaloric material layer. Under the influence of the magnetic field, the magnetic moments of the magnetocaloric material align in an ordered manner, entropy decreases, and the temperature rises by 3-7°C. Heat is transferred from the generator to the magnetocaloric material. In the heat transfer phase, the heat from the magnetocaloric material is transferred to the phase change energy storage module via thermal conduction. In the demagnetization cooling phase, the permanent magnet array rotates until the magnetic field is parallel to the magnetocaloric material layer. The magnetic field strength weakens significantly, the magnetic moments of the magnetocaloric material become disordered, entropy increases, and the temperature decreases by 3-7°C, restoring its heat absorption capacity.

[0035] During the phase change energy storage stage, the heat transferred to the phase change material is absorbed. When the temperature reaches the phase change point, the phase change material undergoes a solid-liquid phase change, absorbing a large amount of latent heat, and the temperature remains basically constant. During the regeneration stage, at night or during low-load periods, the phase change material naturally dissipates heat to the environment, solidifies, and returns to a solid state, preparing for the next working cycle.

[0036] like Figure 1As shown, the cooling system of this invention is applied to a 5MW doubly-fed asynchronous wind turbine. The system comprises three main parts: a cooling layer mounted on the outer surface of the generator stator, a magnetic field modulation assembly, and a drive mechanism.

[0037] By constructing a solid-state multilayer composite cooling structure consisting of a thermally conductive interface layer, a magnetocaloric material layer, a phase change energy storage layer, and an insulating outer shell layer, and combining it with a non-contact ring-shaped rotating magnetic field component, a coupled heat dissipation mechanism of magnetocaloric effect and phase change energy storage is achieved, enabling the motor to achieve efficient heat dissipation without relying on a circulating liquid heat transfer loop. This structure can achieve active temperature regulation by generating alternating heating and cooling effects through the magnetocaloric material under the action of a periodic magnetic field; achieve low thermal resistance heat transfer through a continuous solid-state heat conduction path; avoid the leakage risk and maintenance complexity of liquid cooling systems; improve system reliability and safety; reduce volume and structural complexity; and is suitable for closed or high-reliability scenarios.

[0038] like Figure 2 As shown, the cooling layer, from the inside out, includes: a thermally conductive interface: 0.1 mm thick, with a thermal conductivity >3 W / m·K, ensuring good contact with the stator surface; a magnetocaloric material layer: 2 mm thick, made of Gd5Si2Ge2 alloy, divided into 12 independent regions; a phase change energy storage layer: 8 mm thick, made of paraffin / graphene composite material, with a phase change temperature of 65 °C; and a thermal insulation outer shell layer: 2 mm thick, preventing heat loss to unnecessary parts.

[0039] The thermally conductive interface layer is an insulating thermally conductive material layer, enabling the magnetocaloric material layer to achieve surface contact and adhesion with the motor stator winding. By setting a thermally conductive interface layer composed of insulating thermally conductive material, the magnetocaloric material layer and the motor stator winding achieve surface contact and adhesion, significantly reducing contact thermal resistance while ensuring electrical insulation safety; improving the efficiency of heat transfer from the winding to the magnetocaloric material layer; preventing the risk of electrical short circuits; and enhancing the system's operational stability and safety level.

[0040] The permanent magnet array employs a Halbach structure, comprising 32 N52 neodymium iron boron magnets, each measuring 50×50×20mm. The magnets are mounted on an aluminum alloy bracket and rotated via bearings. The drive motor is a 400W brushless servo motor equipped with a 23-bit absolute encoder.

[0041] The magnetocaloric material layer is a continuous layered structure composed of a metal alloy or composite magnetocaloric material with a magnetocaloric effect. By using a continuous layered structure of a metal alloy or composite magnetocaloric material with a magnetocaloric effect, the magnetocaloric material layer can: generate a significant magnetocaloric response under the influence of a magnetic field; improve the thermal regulation capability per unit volume; form a uniform and continuous heat conduction path; avoid the increased thermal resistance caused by particulate dispersion; and improve the overall structural stability and service life.

[0042] The magnetic field modulation component is a permanent magnet array structure arranged along the axial or circumferential direction of the motor, with the magnetization direction of adjacent permanent magnet units changing sequentially at a preset angle. By arranging the permanent magnet array structure with the magnetization direction changing sequentially at a preset angle along the axial or circumferential direction, the following are achieved: a periodically changing stable magnetic field distribution; enhanced magnetic field modulation uniformity; improved magnetization and demagnetization efficiency of the magnetocaloric material; optimized magnetic field gradient, increasing the magnetocaloric temperature difference amplitude; and improved cooling efficiency and control precision.

[0043] The magnetic field modulation component is supported by bearings on the motor end plate or housing structure, maintaining a non-contact air gap with the solid-state cooling layer. The bearing support structure ensures this air gap, and the drive mechanism rotates the magnetic field modulation component around the solid-state cooling layer, causing periodic changes in the strength and / or direction of the magnetic field acting on the magnetocaloric material layer through the air gap. This achieves mechanical isolation, preventing wear; reduces vibration transmission; improves rotational stability; extends structural lifespan; and ensures stable magnetic field operation without physical interference. The phase change energy storage layer is an encapsulated composite phase change material layer, containing a phase change matrix material and a thermally enhanced structure. The encapsulated composite phase change material layer with an internal thermally enhanced structure improves the thermal conductivity of the phase change material; enhances heat absorption and release efficiency; extends the effective thermal buffer time; prevents localized overheating of the phase change material; and increases energy storage density and system stability.

[0044] The phase change energy storage layer incorporates a microcapsule encapsulation structure to restrict the flow of the phase change material during the solid-liquid transition process. This microcapsule encapsulation restricts material flow during the solid-liquid transition, preventing leakage, improving cycle stability, reducing phase separation issues, extending service life, and enhancing structural safety. The magnetocaloric material layer is directly adjacent to the phase change energy storage layer along its thickness direction, forming a continuous solid-state heat conduction path. This allows the heat generated by the magnetocaloric material layer under the alternating magnetic field to be transferred to the phase change energy storage layer, where it is absorbed and stored through the phase change process.

[0045] The cooling system also includes a temperature acquisition unit and a control unit. The control unit adjusts the working state of the drive mechanism according to the motor temperature to change the magnetic field action period of the magnetic field modulation component.

[0046] By setting up a temperature acquisition unit and a control unit, and adjusting the working state of the drive mechanism according to the motor temperature, the magnetic field cycle can be dynamically adjusted, the cooling capacity can be output on demand, unnecessary energy consumption can be reduced, overcooling or insufficient cooling can be prevented, the system's intelligence level can be improved, and adaptive thermal management control can be achieved.

[0047] The intelligent control system includes: main controller: STM32F407 microprocessor; temperature acquisition module: 12-channel PT1000 temperature sensors; motor drive module: 3 TMC5160 stepper drivers; communication module: CAN bus and Ethernet interface; power supply module: 400VAC to 24VDC power supply.

[0048] Temperature acquisition unit: A network of temperature sensors deployed in key parts of the generator to collect temperature data in real time.

[0049] Magnetic field control unit: Based on the temperature signal, it uses a model predictive control algorithm to calculate the optimal magnetic field parameters and control the rotation angle, speed and dwell time of the permanent magnet array.

[0050] When the system is working, the intelligent control module controls the permanent magnet array to rotate periodically according to the generator temperature and load status.

[0051] During the magnetization heating stage, the permanent magnet array rotates to a position where the magnetic field passes perpendicularly through the magnetocaloric material layer. Under the influence of the magnetic field, the magnetic moments of the magnetocaloric material align in an orderly manner, the entropy decreases, and the temperature rises by 3-7°C. Heat is then transferred from the generator to the magnetocaloric material.

[0052] During the heat transfer phase, the heat from the magnetocaloric material is transferred to the phase change energy storage module through thermal conduction.

[0053] During the demagnetization and cooling stage, the permanent magnet array rotates to a position where the magnetic field is parallel to the magnetocaloric material layer. The magnetic field strength is greatly reduced, the magnetic moment of the magnetocaloric material becomes disordered, the entropy increases, the temperature decreases by 3-7℃, and the heat absorption capacity is restored.

[0054] During the phase change energy storage stage, the heat transferred to the phase change material is absorbed. When the temperature reaches the phase change point, the phase change material undergoes a solid-liquid phase change, absorbing a large amount of latent heat, and the temperature remains basically unchanged.

[0055] During the regeneration phase, at night or during periods of low load, the phase change material naturally dissipates heat to the environment, solidifies and returns to a solid state, preparing for the next working cycle.

[0056] Based on historical temperature and load data, the system predicts future temperature trends; it automatically adjusts magnetic field parameters according to ambient temperature and generator load; and in the event of certain faults, the system can degrade to ensure basic cooling functionality.

[0057] All-solid-state design, zero leakage risk: The system contains no liquid working fluid, fundamentally eliminating the risk of leakage, making it particularly suitable for applications with difficult maintenance, such as offshore wind power. Maintenance-free operation: With no moving sealing components, there is no need for coolant replacement, pipeline cleaning, or other maintenance work, significantly reducing operation and maintenance costs.

[0058] High reliability and long lifespan; the main components are designed for a lifespan of over 20 years, and the magnetocaloric material has a cycle life of over 10 years.9 This is significantly higher than traditional systems. The system's energy consumption is only 20-30% of that of traditional water-cooled systems, and its overall energy efficiency ratio (COP) can reach 5-8. It has strong environmental adaptability and can operate normally in a wide temperature range of -40℃ to +60℃, without being limited by freezing or boiling.

[0059] Precise temperature control employs intelligent predictive control, keeping temperature fluctuations within ±2℃, thus extending generator insulation life. Modular design facilitates installation and maintenance, and can be flexibly configured according to generator power. Environmentally friendly and pollution-free, it uses no chemical coolants, and its materials have a recyclability rate exceeding 95%.

[0060] The installation of the cooling system in the generator includes the following steps: removing the existing water cooling system; cleaning the stator surface; applying thermally conductive adhesive; installing the cooling layer module; installing the rotating magnetic ring; connecting the electrical wiring; and system commissioning.

[0061] like Figure 3 As shown, the temperature of the magnetocaloric material changes periodically under the influence of a magnetic field. From t0 to t1, the magnetic field strengthens, and the temperature rises from T1 to T2 (ΔT≈5℃). From t1 to t2, heat is transferred to the phase change material. From t2 to t3, the magnetic field weakens, and the temperature drops from T2 to T1.

[0062] t3-t4: Heat absorption from the generator. The temperature changes over time through multiple stages, including a heating stage, a constant temperature stage, and a cooling stage. The temperature difference between adjacent temperature ranges is preferably 5℃.

[0063] like Figure 4 The diagram illustrates the thermal response of the phase change material. Below the phase change point Tp, sensible heat is absorbed, and the temperature rises linearly. Upon reaching Tp, latent heat is absorbed, and the temperature remains essentially constant. After the phase change is complete, sensible heat is absorbed, and the temperature continues to rise. The temperature change over time goes through several stages, including a heating stage, an isothermal stage, and a reheating stage. The isothermal stage corresponds to a temperature plateau range, which is adjustable from 45 to 85°C.

[0064] like Figure 5 As shown, a second aspect of the present invention discloses a cooling method for a motor cooling system based on magnetocaloric phase change coupling. The method includes: setting a solid-state cooling layer outside the motor stator windings; driving a magnetic field modulation component to rotate around the solid-state cooling layer, causing periodic changes in the strength and / or direction of the magnetic field acting on the magnetocaloric material layer; thereby causing the magnetocaloric material layer to undergo magnetization and demagnetization processes, resulting in alternating temperature increases and decreases. During demagnetization, the temperature of the magnetocaloric material layer decreases, absorbing heat from the motor; during magnetization, the temperature of the magnetocaloric material layer increases, transferring the absorbed heat to the phase change energy storage layer through a continuous solid-state heat conduction path. The phase change energy storage layer absorbs the heat.

[0065] By employing a magnetocaloric phase change coupling cooling method, active thermal regulation is achieved through magnetization and demagnetization cycles. The heat generated by the motor is efficiently introduced into the phase change energy storage layer, and the latent heat of the phase change is used for heat buffering and storage, realizing a fully solid-state heat transfer process, avoiding liquid circulation systems, and improving the reliability and environmental adaptability of the cooling system.

[0066] The switching frequency of the magnetic field modulation component is adjusted according to changes in motor load or temperature. By adjusting the switching frequency of the magnetic field modulation component based on changes in motor load or temperature, dynamic matching between cooling capacity and heat generation power is achieved; this improves the system's energy efficiency ratio, avoids energy waste caused by a fixed magnetic field frequency, improves thermal response speed, and enhances the system's adaptability and control precision.

[0067] For large wind turbines (≥10MW), a modular design can be adopted. The cooling layer is divided into multiple independent units, each measuring 500×500mm, containing independent magnetocaloric materials, phase change materials, and miniature rotating magnets. These units are connected in parallel via a bus and coordinated by a main controller. The advantages of this design are: localized damage does not affect overall operation; it facilitates installation and maintenance; and it allows for targeted cooling of hotspot areas.

[0068] The control algorithm employs a model predictive control (MPC) framework. The state-space model of the system is established as follows: (1) (2) Where x is the state vector, such as temperature or magnetic field strength, u is the control input, such as motor speed, y is the output, such as temperature measurement, and w and v are noise.

[0069] Solve the optimization problem in each control cycle: (3) The constraints are as follows: .

[0070] The following are the results of testing a 5MW cooling system prototype:

[0071] The magnetocaloric phase change coupled cooling system and control method provided by this invention achieves efficient, reliable, and maintenance-free cooling of wind turbines through an innovative combination of magnetocaloric effect and phase change energy storage. The system is particularly suitable for applications such as offshore wind power and harsh environments. The main materials used in this invention, such as gadolinium alloy, permanent magnets, and phase change materials, are all commercially available products with mature manufacturing processes. The system is compatible with existing wind turbines and is easy to retrofit. According to calculations, for a 5MW wind turbine, the system's investment payback period is approximately 2-3 years, demonstrating significant economic benefits.

[0072] By combining optimized heat conduction with enhanced magnetocaloric effect, the optimal balance is found between heat conduction efficiency, magnetic field efficiency, and engineering feasibility.

[0073] The magnetocaloric material layer, made of gadolinium-based alloy with a thickness of 1-3 mm, is tightly bonded to the surface of the generator stator windings via a thermally conductive adhesive layer. Integrating the magnetocaloric phase-change cooling layer directly into the generator winding insulation system achieves the closest and most efficient cooling while maintaining the integrity and reliability of the electrical insulation.

[0074] The rotatable permanent magnet array adopts a Halbach array structure, achieving a sinusoidal change in magnetization direction, with the magnetic field strengthening on one side and weakening on the other. 85% of the magnetic energy is concentrated on the magnetocaloric material side, and the magnetic field utilization rate is 1.8-2.0 times that of traditional arrays. The harmonic content of the sinusoidal magnetic field waveform is <5%. The 32 magnets are independently installed, facilitating manufacturing and maintenance. It includes multiple permanent magnet units arranged in a ring, with the magnetization directions of adjacent permanent magnet units differing by (45°-90°).

[0075] The composite phase change material layer is a composite material of paraffin-based phase change material and graphene, with an adjustable phase change temperature of 45-85℃ and an internal honeycomb microcapsule structure. It adopts a gradient composite structure for high space efficiency; independent zoned control allows for targeted cooling of hot spots; microcapsule leakage prevention design; and integrated design with temperature sensors directly embedded in the magnetocaloric layer.

[0076] The technical effects achieved by the invention are as follows: By coupling the reversible changes in magnetization and demagnetization temperature of the magnetocaloric material layer with the latent heat absorption of the phase change energy storage layer, a fluidless solid-state thermal regulation cycle is formed, realizing rapid heat removal and peak suppression of the motor windings; The layered bonding structure shortens the heat transfer path and reduces the interface thermal resistance, while the phase change energy storage smooths the temperature rise caused by load fluctuations, improving temperature control stability and insulation life; Non-contact air gap magnetic coupling avoids dynamic seals and liquid circuits, reducing leakage and maintenance risks, and improving the long-term reliability and environmental adaptability of the system.

[0077] The technical solution of the present invention is illustrated below through specific embodiments. It should be understood that the one or more steps mentioned in the present invention do not preclude the existence of other methods and steps before or after the combined steps, or that other methods and steps may be inserted between these explicitly mentioned steps. It should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Unless otherwise stated, the numbering of each method step is only for the purpose of identifying each method step, and not for limiting the order of each method or limiting the scope of the present invention. Changes or adjustments to their relative relationships, without substantial changes to the technical content, can also be considered as within the scope of the present invention.

[0078] The raw materials and instruments used in the examples are not subject to any specific restrictions on their source; they can be purchased from the market or prepared according to conventional methods known to those skilled in the art.

[0079] The foregoing description of specific exemplary embodiments of the invention is for illustrative and explanatory purposes. These descriptions are not intended to limit the invention to the precise forms disclosed, and it will be apparent that many changes and variations can be made in accordance with the foregoing teachings. The exemplary embodiments were chosen and described in order to explain the specific principles of the invention and its practical application, thereby enabling those skilled in the art to implement and utilize various different exemplary embodiments of the invention, as well as various different choices and variations. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A motor cooling system based on magnetocaloric phase change coupling, characterized in that, The system includes: A solid cooling layer disposed on the outer surface of the motor stator winding, the solid cooling layer comprising, from the inside out: a thermally conductive interface layer, a magnetocaloric material layer, a phase change energy storage layer, and a thermally insulating outer shell layer; A magnetic field modulation component is disposed on the outside of the solid cooling layer. The magnetic field modulation component includes a plurality of magnetic field units arranged circumferentially to form a rotating magnetic field. A non-contact air gap is formed between the magnetic field modulation component and the magnetocaloric material layer. The driving mechanism includes an electric motor and a transmission structure connected to the magnetic field modulation component, used to drive the magnetic field modulation component to rotate around the solid cooling layer; causing the magnetic field strength and / or direction acting on the magnetocaloric material layer to change periodically, thereby causing the magnetocaloric material layer to undergo magnetization and demagnetization processes, resulting in alternating changes in temperature rise and temperature fall; a continuous solid-state heat conduction path is formed between the magnetocaloric material layer and the phase change energy storage layer, and the heat insulation shell layer is used to reduce heat exchange between the system and the external environment.

2. The cooling system according to claim 1, characterized in that, The thermally conductive interface layer is an insulating thermally conductive material, which enables the magnetocaloric material layer to achieve surface contact and bonding with the motor stator winding.

3. The cooling system according to claim 1, characterized in that, The magnetocaloric material layer is a continuous layered structure composed of a metal alloy or composite magnetocaloric material with a magnetocaloric effect.

4. The cooling system according to claim 1, characterized in that, The magnetization direction of the adjacent magnetic field units changes sequentially according to a preset angle.

5. The cooling system according to claim 1, characterized in that, The magnetic field modulation component is supported on the motor end plate or housing structure by bearings and maintains a non-contact air gap with the solid cooling layer.

6. The cooling system according to claim 1, characterized in that, The phase change energy storage layer is an encapsulated composite phase change material layer, which contains a phase change matrix material and a thermally conductive enhancement structure.

7. The cooling system according to claim 6, characterized in that, The phase change energy storage layer is equipped with a microcapsule encapsulation structure to restrict the flow of the phase change material during the solid-liquid transition process.

8. The cooling system according to claim 1, characterized in that, The cooling system further includes a temperature acquisition unit and a control unit. The control unit adjusts the operating parameters of the drive mechanism based on the temperature information acquired by the temperature acquisition unit to change the magnetic field of the magnetic field modulation component.

9. A cooling method for a motor cooling system based on magnetocaloric phase change coupling, characterized in that, The method includes: A solid cooling layer is installed on the outside of the motor stator winding; The magnetic field modulation component is driven to rotate around the solid cooling layer, causing the intensity and / or direction of the magnetic field acting on the magnetocaloric material layer to change periodically; thereby causing the magnetocaloric material layer to undergo magnetization and demagnetization processes, resulting in alternating changes in temperature rise and temperature fall; During demagnetization, the temperature of the magnetocaloric material layer decreases, absorbing heat from the motor; during magnetization, the temperature of the magnetocaloric material layer increases, transferring the absorbed heat to the phase change energy storage layer through a continuous solid-state heat conduction path. The phase change energy storage layer absorbs the heat.

10. The cooling method according to claim 9, characterized in that, The frequency of change in the magnetic field strength and / or direction generated by the magnetic field modulation component is adjusted according to changes in motor load or temperature.

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