Power self-adaptive axial magnetic flux permanent magnet motor internal and external integrated self-driven cooling device

Abstract

The invention discloses an internal and external integrated self-driven cooling device of a power self-adaptive axial flux permanent magnet motor. The internal active driving cooling part is of a fan-shaped disc unit structure and is installed between an air gap of a stator and an air gap of a rotor; the external passive driving heat dissipation part is of an arc-shaped cylinder unit structure and is mounted at the outer arc of the internal active driving cooling part; the sealing magnetic suction interface part is used for tightly connecting the internal active drive cooling part and the external passive drive heat dissipation part; the magnetic shielding heat conduction bridge part is used for isolating an internal air-gap magnetic field and transmitting internal heat to the outside in a heat conduction manner; the cooling medium is magnetic fluid and is used for magnetic sealing, magnetic field intensity adaptation and efficient heat exchange. The heat dissipation structure is designed according to the operation mode of the motor magnetic field and the magnetic force performance and the magnetothermal performance of the magnetofluid so as to achieve self-driving and self-cooling of the motor closed cooling system, the cooling effect of being adaptive to heating values of motors with different powers can be achieved, and self-adaptive cooling regulation and control of the motor powers can be achieved.

Description

Technical Field

[0001] The invention relates to an axial flux permanent magnet motor, and in particular to an internal and external integrated self-driving cooling device for a power adaptive axial flux permanent magnet motor. Background Art

[0002] Axial flux permanent magnet motors have a very significant high torque density due to their high aspect ratio (large radius, short axis length) topology. In order to improve the power density of axial flux permanent magnet motors and miniaturize the drive propulsion system, the development direction towards higher speeds has become an inevitable trend. However, as the power density of motors continues to increase, the electromagnetic losses inside them will increase accordingly. Without efficient cooling structures or equipment, thermal failures caused by overheating of key parts of the motor have become a bottleneck restricting the development of the electrical industry. In order to improve the cooling and heat dissipation capabilities of motors, a variety of cooling methods such as air cooling, liquid cooling and phase change cooling have been proposed, and good cooling and heat dissipation effects have been obtained in the actual operation of the motors.

[0003] At present, the best cooling method for motors is to increase the pressure of the cooling medium by regulating external pressurizing equipment to achieve the purpose of circulation. At the same time, for the cooling medium after absorbing heat, more complex cooling equipment is also required to cool it down. These external devices not only increase the supporting cost and volume of the motor, but also there will be a risk of leakage at the connection between the inlet and outlet and the external equipment. In addition, complex program design and status monitoring are also required to adjust the heat dissipation of external equipment to match the heat generated by the motor when running at different powers, which undoubtedly puts higher requirements on the adaptability and intelligence of motor cooling equipment.

[0004] To this end, the applicant has proposed a power adaptive integrated self-driving cooling device for an axial flux motor using a magnetic fluid as a cooling medium.

[0005] The description of magnetic fluid is as follows: As a mixed colloidal solution of magnetic particles, carrier liquid and active agent, magnetic fluid has controllable rheological properties that change with the strength of the external magnetic field. Under the action of the external magnetic field, magnetic fluid can show both the strong magnetism of solid magnetic materials and the fluidity of liquids. In addition, the magnetocaloric effect exhibited by magnetic materials may be applied to heating, cooling and magnetic energy conversion technologies. Summary of the invention

[0006] The object of the present invention is to provide a self-driving cooling device for an axial flux permanent magnet motor with power adaptation and internal and external integration.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions: The power adaptive axial flux permanent magnet motor has an internal and external integrated self-driven cooling device, including a cooling medium, an internal active driving cooling part and an external passive driving heat dissipation part; The internal active drive cooling part is used to absorb the heat generated by the heat generating structure on the stator side and the rotor side structure of the motor, as well as the heat conducted into the air gap; the internal active drive cooling part is a fan-shaped disk unit structure and is installed between the stator and rotor air gaps, and N fan-shaped disk unit structures are periodically distributed and arranged along the circumferential direction to form a circular disk structure; The main body of each sector disk unit structure is provided with an inlet section flow channel, an outlet section flow channel and m cooling elbows arranged radially, each cooling elbow extends along the circumferential direction of the air gap magnetic field movement to form a magnetic field enhanced cooling elbow, and the cooling elbow is located between the internal inlet section flow channel and the internal outlet section flow channel and is connected to the two; The external passively driven heat dissipation part is used to realize the demagnetization of the cooling medium magnetic fluid so as to cool it quickly; the external passively driven heat dissipation part is an arc-shaped cylinder unit structure, which corresponds to the internal active driven cooling part one by one and the unit has the same circumferential coverage angle; the external passively driven heat dissipation part is installed at the outer arc corresponding to the internal active driven cooling part, and N arc-shaped cylinder unit structures are arranged in a periodic distribution along the circumferential direction and can be spliced ​​to form a cylindrical structure; a demagnetization symmetrical array of heat dissipation pipes is arranged in the main body of the external passively driven heat dissipation part, and the heat dissipation pipe has a heat dissipation pipe inlet and a heat dissipation pipe outlet; The inlet section flow channel of the internal active driving cooling part is connected to the outlet of the heat dissipation pipe of the external passive driving heat dissipation part, and the outlet section flow channel of the internal active driving cooling part is connected to the inlet of the heat dissipation pipe of the external passive driving heat dissipation part, thereby forming a cooling cycle; A gap is left in the radial direction between the internal active drive cooling part and the external passive drive heat dissipation part; The cooling medium is a magnetic fluid, which is filled in the pipelines of the internal active drive cooling part and the external passive drive heat dissipation part; the magnetic fluid utilizes the axial magnetic field of the axial flux permanent magnet motor to achieve self-driving and power adaptation.

[0008] Furthermore, the outer diameter of the internal active drive cooling part is the same as the outer diameter of the stator side structure, and the inner diameter is the same as the inner diameter of the rotor side structure; one axial side of the internal active drive cooling part is in contact with the stator part, and the other axial side of the internal active drive cooling part is in clearance with the rotor part.

[0009] Furthermore, the main body of the internal active drive cooling part is made of non-metallic material, and a flow channel is opened in the main body to form an inlet section flow channel, an outlet section flow channel and a cooling elbow; the inlet section flow channel and the outlet section flow channel are respectively extended radially and the inlet and outlet pipe diameters of the two are the same, that is, the pipe diameter of the internal magnetic suction interface; The axial thickness of the internal active drive cooling part is positively correlated with the motor power, and a certain margin should be left to prevent collision and wear.

[0010] Furthermore, the number m of cooling bends arranged radially is the same as the number of turns of the stator winding; the m cooling bends are set with unequal diameters, and their diameters are positively correlated with the air gap magnetic field strength, that is, the diameter of the bend in the middle is the largest, gradually decreasing toward the inside and outside, and does not exceed the axial reliability thickness of the internal active drive cooling part.

[0011] Furthermore, the main body of the external passively driven heat dissipation part is made of a material with high thermal conductivity and low magnetic permeability, and a flow channel is provided in the main body to form a heat dissipation pipe; The heat dissipation pipe inlet and heat dissipation pipe outlet of the external passive drive heat dissipation part are located at the central radial section of the internal active drive cooling part, and the pipe diameters of the two are the same, that is, the pipe diameter of the external magnetic suction interface; the heat dissipation pipes of the external passive drive heat dissipation part are arranged in two groups axially symmetrically about the central radial section, and the axial length is greater than the circumferential length; both groups of heat dissipation pipes are S-shaped connections; The radial thickness of the external passive drive heat sink is positively correlated with the motor power.

[0012] Furthermore, the number of units N of the internal active drive cooling part / external passive drive heat dissipation part is consistent with the number of rotor poles; the circumferential span of the unit of the internal active drive cooling part is .

[0013] Furthermore, an inner magnetic suction interface is provided at the outer side of the inlet section flow channel and the outlet section flow channel, and an outer magnetic suction interface is provided at the inlet and outlet of the heat dissipation pipe; The inlet section flow channel of the internal active driven cooling part and the heat pipe outlet of the external passive driven heat dissipation part are connected through the matching internal magnetic attraction interface and the external magnetic attraction interface to form a sealed magnetic attraction interface part, and the outlet section flow channel of the internal active driven cooling part and the heat pipe inlet of the external passive driven heat dissipation part are connected through the matching internal magnetic attraction interface and the external magnetic attraction interface to form a sealed magnetic attraction interface part, thereby realizing a highly sealed cooling cycle.

[0014] Furthermore, the internal magnetic interface is located in the magnetic field, and has a lower flow pipe, which is an extension of the inlet section flow channel / outlet section flow channel of the internal active drive cooling part, and has a main coil on the outside of the lower flow pipe; a plurality of iron core bolts extending upward are arranged around the lower flow pipe, and a secondary coil is wound around the lower half of the iron core bolt, and the secondary coil is connected to the main coil; when the cooling medium passes through the lower flow pipe from bottom to top, it will induce current on the main coil and transmit it to the secondary coil, and the secondary coil makes the iron core bolt magnetic through electric excitation, and induces polarity at the upper end; The external magnetic interface has an upper circulation pipeline, which is an extension of the heat dissipation pipe inlet / heat dissipation pipe outlet of the external passively driven heat dissipation part. A card slot is provided at a position corresponding to the core bolt on the external magnetic interface, and a strong magnetic material with a polarity different from that of the core bolt end is provided inside the card slot; the card slot and the upper circulation pipeline are connected through the lower inlet hole and the upper outlet hole; The interface between the inner magnetic interface and the outer magnetic interface is composed of strong magnetic materials with different magnetic properties.

[0015] Furthermore, an arc-shaped area is formed at the gap between the internal active drive cooling part and the external passive drive heat dissipation part, and an inner and outer magnetic isolation heat transfer bridge part is provided at the arc-shaped area; the inner and outer magnetic isolation heat transfer bridge part is tightly fitted with the internal active drive cooling part and the external passive drive heat dissipation part, and the inner and outer magnetic isolation heat transfer bridge part is used to isolate the internal air gap magnetic field and transfer the heat of the internal active drive cooling part to the external passive drive heat dissipation part by heat conduction; The inner and outer magnetic insulation heat transfer bridge parts include a composite plate, which is formed by stacking heat-conducting and magnetic-conducting layers and heat-conducting non-magnetic-conducting layers alternately arranged in the radial direction. At the same time, there are multiple heat-conducting holes distributed in the circumferential direction on the composite plate. The heat-conducting holes extend radially and penetrate the composite plate, and directional heat-conducting columns are filled in the heat-conducting holes.

[0016] Furthermore, the Curie temperature of the magnetic fluid used as the cooling medium Higher than the hot spot temperature of the motor To avoid demagnetization at high temperature; the saturation magnetization intensity of the magnetic fluid is lower than the synthetic magnetic field intensity of the air gap to reduce the consumption of magnetic field energy.

[0017] The beneficial effects of the present invention are: 1. The present invention designs an active-passive combined self-driven cooling device with an internal active-driven cooling part and an external passive-driven heat dissipation part to achieve self-driving and self-cooling of the cooling system, greatly reducing the cost and system volume of external boosting equipment and auxiliary cooling equipment, and enhancing the reliability and power density of the system.

[0018] The present invention utilizes the magnetic and magnetocaloric properties of magnetic fluid to achieve self-driving and self-cooling of a closed cooling system, and has the effect of being affected by a rotating magnetic field to adapt the power and loss heat of the motor at different torques and speeds, so as to achieve adaptive cooling control of the motor power.

[0019] 2. The internal active drive cooling part is filled with magnetic fluid as a cooling medium, and its magnetic properties are used to increase the magnetic permeability between the stator and the rotor, thereby reducing the magnetic pressure drop between the stator and rotor air gaps, indirectly increasing the air gap magnetic density, and thus improving the electromagnetic performance of the motor; at the same time, the cooling medium magnetic fluid has the effect of being pulled by the rotating magnetic field to adapt to the power and loss heat of the motor under different torques and speeds, so as to achieve adaptive cooling control of the motor power.

[0020] 3. In order to maximize the heat exchange efficiency of the cooling device, the magnetocaloric properties of the cooling medium magnetic fluid must be fully utilized. To this end, this patent designs a demagnetized symmetrical array heat pipe structure for the internal and external magnetic isolation heat transfer bridge parts and the external passive drive heat dissipation part. The combined effect of the two will limit the air gap magnetic field to only inside the motor, and the magnetic fluid in the external passive drive heat dissipation part will be demagnetized, thereby fully utilizing the magnetocaloric effect to fully release heat to the external area.

[0021] 4. The present invention also designs a sealed magnetic interface part, which not only realizes the high sealing performance and super strong fixing ability of the motor during operation, but also is used to realize the detachable connection between the internal active drive cooling part and the external passive drive heat dissipation part, so that different internal active drive cooling parts and external passive drive heat dissipation parts can be replaced according to motors with different parameters under different operating conditions for combined cooling. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is an overall schematic diagram of the present invention; Figure 2 It is an overall front view of the present invention; Figure 3 It is an overall side view of the present invention; Figure 4 It is an overall top view of the present invention; Figure 5 This is a schematic diagram of the structure of the internal active drive cooling part of the present invention. Figure 6 It is a schematic diagram of the principle of the internal active drive cooling part in the present invention; Figure 7 It is a schematic diagram of the structure and principle of the external passive drive heat dissipation part in the present invention; Figure 8 It is a schematic diagram of the structure and principle of the sealed magnetic interface part of the present invention; Fig. 9 It is a front view of the inner and outer magnetic isolation and heat transfer bridge part of the present invention; Fig.10 A top view of the inner and outer magnetic isolation and heat transfer bridges of the present invention; Fig.11 It is a side view of the inner and outer magnetic isolation and heat transfer bridge part of the present invention.

[0023] The drawings are only used for illustrative purposes and should not be construed as limitations on this patent. In order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged, or reduced, and do not represent the size of the actual product. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0025] Embodiment 1: like Figures 1 to 11 As shown, this embodiment discloses an internal and external integrated self-driven cooling device for a power adaptive axial flux permanent magnet motor, which mainly includes a cooling medium 1, an internal active driving cooling part 2, an external passive driving heat dissipation part 3, a sealed magnetic attraction interface part 4 and an internal and external magnetic isolation heat transfer bridge part 5. The cooling device is installed and attached to the stator surface between the stator and rotor air gaps to fully cool the stator, rotor and air gap.

[0026] The cooling medium 1 is a magnetic fluid, which is filled in all the pipes in the cooling device. The cooling medium 1 in the internal active drive cooling part 2 is actively driven by the rotating synthetic magnetic field inside the motor, so it has a certain momentum (the higher the power of the motor, the higher the driving strength, and thus the cooling medium has a higher kinetic energy). At the same time, the synthetic magnetic field magnetizes the cooling medium to make it magnetic (this process uses the magnetocaloric property of the magnetic fluid to absorb heat), thereby reducing the air gap magnetic resistance and increasing the magnetic field strength of the motor gap. The cooling medium 1 in the internal active drive cooling part 2 has its own momentum and enters the external passive drive heat dissipation part 3. This process causes the cooling medium 1 in the external passive drive heat dissipation part 3 to continue to circulate under the passive drive. At the same time, the heat dissipation pipe 33 of the demagnetization symmetrical array in the external passive drive heat dissipation part 3 and the internal and external magnetic insulation heat transfer bridge part 5 will limit the internal synthetic magnetic field to only within the motor and completely demagnetize the magnetized cooling medium 1 (this process uses the magnetocaloric property of the magnetic fluid to release heat). In addition, during the operation of the motor, the sealed magnetic interface part 4 is excited and sealed by the cooling medium 1 having momentum and magnetism, so that the internal active drive cooling part 2 and the external passive drive heat dissipation part 3 can be closely connected. The above cooling device ultimately achieves the effects of power adaptation, self-driving and self-cooling.

[0027] Since the axial flux motor has periodicity in the circumferential direction and the number of units can be adjusted according to the motor's own structure and power, the cooling device will be designed as a periodically distributed unit structure (to meet the rotor heat dissipation effect, the number is consistent with the number of rotor poles, which is N periodic units). The cooling structure of the unit body is mainly composed of the circumferential span. The internal active drive cooling part 2 and the circumferential span of the sector disk unit structure The external passively driven heat dissipation part 3 of the arc-shaped cylinder thin-walled unit structure is composed. The internal active driven cooling part 2 of the multiple fan-shaped disk unit structure is periodically distributed and arranged along the circumference and spliced ​​to form a circular disk structure, and the external passively driven heat dissipation part 3 of the multiple arc-shaped cylinder thin-walled unit structure is periodically distributed and arranged along the circumference and spliced ​​to form a cylindrical structure.

[0028] The cooling device of a cycle unit is used for explanation, such as Figure 2-4 shown.

[0029] External radius of internal active drive cooling section 2 With stator outer radius The same, its inner diameter is the same as the minimum inner diameter of the stator and rotor side structures (i.e. ), the radial length of this part is This part of the structure is used to cool the stator side part 6 (which contains the stator core and stator winding), the air gap 7 and the rotor side part (which contains the magnetic poles and the rotor core) that generate heat. One side of the internal active drive cooling part 2 is in contact with the stator side part 6; the other side is the rotating rotor part 8 (which contains the rotor core and the magnetic poles), and there is a certain designed gap (i.e., the air gap 7) between the two. The external passive drive heat dissipation part 3 is located at the outer radius In addition, the pipe diameter is The demagnetized symmetrical array heat pipe can make full use of the magnetocaloric effect to dissipate the heat absorbed by the cooling medium 1 from the inside to the external environment. The external passive drive heat dissipation part 3 is installed at the outer arc of the internal active drive cooling part 2 and has the same span angle The two are connected through a sealed magnetic interface part 4 to realize cooling cycle. The gap between the internal active drive cooling part 2 and the external passive drive heat dissipation part 3 is the internal and external magnetic isolation heat transfer bridge part 5, which can form a large magnetic resistance in the radial direction to shield the external passive drive heat dissipation part 3 to ensure that there is basically no magnetic field strength, and the heat conduction column inside it can directly transfer the internal active drive cooling part 2 to the external passive drive heat dissipation part 3.

[0030] Cooling medium 1 is a magnetic fluid. Because magnetic fluid is composed of magnetic particles, carrier liquid and activator, the material selection and proportioning of the three determine the magnetism, viscosity, specific heat capacity and magnetocaloric properties of the cooling medium. The magnetism of magnetic fluid determines the magnetic field force it receives in the magnetic field, the viscosity determines the flow loss caused by it in the circulation process, the specific heat capacity determines its heat absorption capacity, and the magnetocaloric properties determine the final effect of its magnetic refrigeration and heat exchange. Therefore, the composition of the cooling medium should be based on the development of the material in the period, and the magnetic fluid medium that can finally present high magnetism, low viscosity, high specific heat capacity and strong magnetocaloric properties should be selected. In addition, the magnetic particles in the magnetic fluid are nanometer level, and the electrical conductivity of the carrier liquid is poor, so there is basically no eddy current loss. Meanwhile, magnetic fluid has superparamagnetism, and its hysteresis loss in the alternating magnetic field can also be ignored.

[0031] like Figures 5 and 6 As shown, the internal active drive cooling part 2 absorbs the heat of the heated stator side part 6 and the rotor side part 8 and the heated air gap part 7 through the cooling medium 1. This part of the structure includes an inlet section flow channel 21, an outlet section flow channel 22 and m unequal diameter cooling elbows 23 arranged radially. The inlet section flow channel 21 and the outlet section flow channel 22 extend radially respectively (based on the principle of minimizing the total flow loss of the magnetic line of force and the pipeline, the arrangement of the inlet section flow channel and the outlet section flow channel in the radial direction is preferred), the cooling elbow 23 is located between the inlet section flow channel and the outlet section flow channel and is connected thereto, and the size of the pipe diameter is designed to be positively correlated with the magnetic field strength (the diameter of the elbow located in the middle is the largest, and gradually decreases toward the inside and outside, and The inlet section flow channel 21 and the outlet section flow channel 22 are both connected to the internal magnetic suction interface 41. Since the cooling medium 1 filled inside is a magnetic fluid, the design method of the unequal diameter cooling elbow can not only meet the adaptation of the active driving ability of the magnetic field strength at different positions, but also use its magnetic performance to improve the magnetic permeability between the stator and the rotor and reduce the magnetic pressure drop, indirectly improving the air gap magnetic density, and thus improving the electromagnetic performance of the motor. The internal active drive cooling part 2 has a certain thickness in the axial direction. The outer diameter of the cooling elbow 23 needs to be smaller than the axial thickness And meet the mechanical strength design requirements.

[0032] In order to avoid eddy current loss in the conductor in the alternating magnetic field, the sector disk body of the internal active drive cooling part 2 is made of non-metallic materials (such as graphene reinforced composite materials, etc.), and after being made, flow channels are opened inside to form inlet section flow channels 21, outlet section flow channels 22 and cooling elbows 23. The pipeline of the internal active drive cooling part 2 is filled with cooling medium 1, which will improve the magnetic permeability of the stator and rotor gap magnetic circuit.

[0033] like Figure 3The principle shown is shown in Figure 1. “·” indicates that the magnetic field lines pass through the plane in the figure, and “×” indicates that the magnetic field lines pass through the plane in the figure. The cooling elbow 23 has an initial velocity And the quality is The magnetic fluid microelement, its synthetic effect Mainly due to the traction of the magnetic field , centrifugal force along circular motion , Magnetic Fluid Gravity , the radial restraint of the pipeline Friction The final acceleration When the continuity of the magnetic fluid element is considered, the rear magnetic fluid element will push the front magnetic fluid element in the direction of motion.

[0034] In t 1 to 2 The cooling temperature is The demagnetized low-temperature magnetic fluid microelement 11 enters each bend from the inlet section flow channel 21. Assuming that the magnetic field lines of the magnetic field pass through the screen at this time, the low-temperature magnetic fluid microelement 11 is magnetized by the magnetic field and then pulled by the magnetic force. Gradually move in a circular direction along the cooling elbow 23.

[0035] In t 2 to 3 At this moment, the magnetic fluid is subjected to the combined force The action gradually moves in the circumferential direction, and at the same time, the temperature of the magnetized medium-temperature magnetic fluid microelement 12 rises due to the magnetocaloric effect. According to the theory of magnetocaloric effect, the temperature change caused by the change of magnetic field under adiabatic conditions is Defined by the following expression: (Formula 1.1) in, is the magnetic field strength between the stator and rotor where the cryogenic magnetic fluid microelement 11 is located, is the specific heat capacity of the low-temperature magnetic fluid microelement 11 under a constant magnetic field, is the magnetization intensity, is the magnetic field strength, is the temperature. From this formula, we know and Inversely proportional, and For the temperature-dependent isothermal magnetic entropy , whose expression is: (Formula 1.2) For the application of magnetocaloric effect in existing cooling equipment, the material and Therefore, the above two points should be fully considered in the selection and configuration of magnetic fluid. In addition, like other magnetic materials, the magnetization intensity of magnetic fluid will decrease with the increase of temperature, and it will also lose its magnetism when it is heated to a certain high temperature, which is called the Curie temperature. Therefore, when preparing magnetic fluid, its Curie temperature should be Much higher than the hot spot temperature of the motor At t 2 to 3 The stage is the main stage of magnetic fluid heat absorption.

[0036] In t 3 to 4 At this moment, it is assumed that the magnetized medium-temperature magnetic fluid microelement 12 at different radial positions flows through the cooling bend 23 and absorbs the heat of the electromagnetic loss of the stator core 01 and the stator winding 02 and then heats up. , it becomes a high-temperature magnetic fluid microelement 13 and reaches the outlet flow channel 22. Assume that the temperature rise caused by flow loss during the whole process is , Mainly affected by the Reynolds number of the magnetic fluid The final temperature of the high-temperature magnetic fluid microelement 13 for: (Formula 1.3) In this process, as the magnetic fluid absorbs heat and the temperature rises, its magnetization intensity gradually weakens due to the magnetocaloric effect, thereby reducing the force acting on it by the magnetic field. Therefore, the magnetization intensity of the low-temperature magnetic fluid element 11 located in the radial bend is higher than that of the medium-temperature magnetic fluid element 12, and the magnetization intensity of the medium-temperature magnetic fluid element 12 is higher than that of the high-temperature magnetic fluid element 13. The magnetic field forces acting on the three also decrease in turn, and the low-temperature magnetic fluid element 11 will move toward the high-temperature magnetic fluid element 13, and then replace the high-temperature magnetic fluid element 13. Therefore, a pressure difference will be formed between the two ends of the cooling bend 23, and the purpose of self-driving the cooling medium will be achieved.

[0037] In addition, the motor has different speeds Corresponding to different motor powers , the synthetic magnetic field in the stator and rotor air gap will also have different speeds After magnetization, the magnetic fluid will be subjected to different speeds. The traction of the rotating magnetic field has different flow rates, and its work and boost capacity are also different. and power When it is larger, the temperature of the high-temperature magnetic fluid microelement The temperature of the motor will also increase, but the magnetic fluid will also have a higher flow rate, which will speed up the cooling cycle and eventually reduce the temperature of the motor. This undoubtedly realizes the adaptive regulation of the cooling system for the motor power.

[0038] like Figure 7 As shown, the function of the external passively driven heat dissipation part 3 is to quickly demagnetize the cooling medium 1 and make full use of the magnetocaloric effect to improve its cooling efficiency so as to achieve rapid cooling of the cooling medium 1. The external passively driven heat dissipation part 3 includes an arc-shaped thin-walled main body made of a material with high thermal conductivity, low magnetic permeability and high structural strength (such as 316L stainless steel, C17200 beryllium bronze, 6061 aluminum, C110 copper, etc.). The arc-shaped thin-walled main body is provided with an external magnetic suction interface 42 at its central radial section, and a heat dissipation pipe 33 with a demagnetizing symmetrical array is designed inside the arc-shaped thin-walled main body. The radial thickness of the external passively driven heat dissipation part 3 is consistent with the axial thickness of the internal actively driven cooling part 2. , the pipe diameter is The demagnetized symmetrical array heat dissipation pipes 33 are distributed along the circumferential direction. The root is axially symmetrical about the central radial section, and the axial length of the heat dissipation pipe on one side is The circumferential length is (Meanwhile satisfying ), the heat dissipation tubes are connected in an S-shaped manner to form two axially symmetrical groups. Consider two magnetic fluid microelements of a symmetrical cooling medium in the axial tube. The magnetic lines of force of the two are opposite in the axial direction, so they have a strong demagnetization effect, but the magnetic field in the circumferential tube is the same and the magnetic field is superimposed and enhanced. Therefore, it is necessary to ensure The units of the external passive drive heat dissipation part 3 and the internal active drive cooling part 2 correspond one to one and the circumferential span angles are The external passive drive heat dissipation part 3 is installed on the radial outer side of the internal active drive cooling part 2, so that the inner magnetic attraction interface 41 and the outer magnetic attraction interface 42 are closely connected.

[0039] The high-temperature magnetic fluid microelement 13 flowing out of the outlet flow channel 22 of the internal active drive cooling part 2 flows into the heat dissipation pipe 33 through the external magnetic suction interface 42 on one side. There is a flow channel for the high-temperature magnetic fluid microelement 13 inside the heat dissipation pipe 33, and the high-temperature magnetic fluid microelement 13 is demagnetized without the action of an external magnetic field. At the same time, heat exchange is carried out between the flow channel wall inside the heat dissipation pipe 33 and the high-temperature magnetic fluid microelement 13, which transfers heat to the heat dissipation pipe 33. The outer circumferential surface of the arc-shaped thin-walled body of the external passive drive heat dissipation part can be in contact with air or other cooling media to achieve secondary heat exchange.

[0040] When the power is high and the heat is high, the number of heat pipes is and pipe diameter Increase accordingly to achieve a strong cooling effect. and pipe diameter The corresponding reduction can achieve the effect of cost saving and lightweight. Finally, it is necessary to ensure that the high temperature magnetic fluid microelement 13 is cooled to Since the magnetic fluid has continuity and there is a pressure difference in the internal active driving cooling part 2, the cooled low-temperature magnetic fluid microelement 11 will be transported from the outlet 32 ​​to the inlet section flow channel 21 of the internal active driving cooling part 2, thereby realizing the overall cooling cycle and finally realizing the self-cooling of the system.

[0041] The number of cycle units N and thickness of the cooling device , Regional span and pipe diameter It should be adjusted according to the power and heat generation of the motor. When the power is large and the heat generation is large, the number of period units N and the thickness , Regional span and pipe diameter Corresponding increase to achieve a strong cooling effect. Conversely, the number of periodic units N and thickness , Regional span and pipe diameter The corresponding reduction can achieve the effect of cost saving and lightweight.

[0042] like Figure 8 As shown, the sealed magnetic interface part 4 is composed of an inner magnetic interface 41 and an outer magnetic interface 42. The two are fixed to the inner active drive cooling part 2 and the outer passive drive heat dissipation part 3 respectively.

[0043] The inner magnetic interface 41 is located in the magnetic field, and has a lower flow pipe 410. The lower flow pipe 410 is an extension of the inlet section flow channel / outlet section flow channel of the internal active drive cooling part, and a main coil 413 is provided on the outside of the lower flow pipe 410; four upwardly extending core bolts 412 are arranged around the lower flow pipe 410, and the lower half of the core bolts 412 is wound with a secondary coil 414, and the secondary coil 414 is connected to the main coil 413 through terminals.

[0044] The external magnetic interface 42 has an upper circulation pipe 420, which is an extension of the heat pipe inlet / heat pipe outlet of the external passively driven heat dissipation part. Four card slots 424 are provided at positions corresponding to the four iron core bolts 412 on the external magnetic interface, and strong magnetic material is provided inside the card slots 424; the card slots 424 are connected to the upper circulation pipe 420 through the lower inlet hole 422 and the upper outlet hole 423.

[0045] The magnetic interface between the inner magnetic interface 41 and the outer magnetic interface 42 is made of ferromagnetic materials with different magnetic properties. Assume that the magnetic property of the first magnetic interface 411 is N and the magnetic property of the second magnetic interface 421 is S. When the motor is not running, the two can also be fixed by the magnetic interface, and a small amount of cooling medium 1 can realize magnetic fluid sealing.

[0046] When the motor is running, the inner magnetic interface 41 is located at the boundary of the magnetic field, and the cooling medium 1 still has strong magnetism and large momentum. When the cooling medium 1 passes through the lower circulation pipe 410 from bottom to top, it will induce current on the main coil 413 and transmit it to the auxiliary coil 414 through the terminal (only one auxiliary coil is marked in the figure for illustration). At this time, the auxiliary coil is wound around the iron core bolt 412, and is made magnetic by electrical excitation, and the S polarity is induced at the upper end.

[0047] When the motor is running, the external magnetic interface 42 is located outside the magnetic field (basically without magnetic field), the magnetic fluid still has some magnetism and momentum, most of the cooling medium 1 passes through the upper circulation pipe 420 from bottom to top, and a small part flows into the slot 424 from the introduction hole 422. When the core bolt 412 completely enters the slot 424, its gap will be filled with cooling medium 1, and the excess will flow into the upper circulation pipe 420 from the outlet hole 423. The inside of the slot 424 is provided with a strong magnetic material with a different polarity from the end of the core bolt 412, which can ensure that the sealed magnetic interface part 4 has a higher adsorption force and sealing when the motor is running.

[0048] like Figures 9 to 11 As shown, the inner and outer magnetic isolation heat transfer bridge part 5 is used to isolate the internal air gap magnetic field and transfer the heat of the internal active drive cooling part to the external passive drive heat dissipation part by heat conduction, while realizing the separation design idea of ​​the internal and external, active and passive. This part is located in the arc area between the internal active drive cooling part and the external passive drive heat dissipation part.

[0049] The inner and outer magnetic heat transfer bridge part 5 is located in the arc gap and is closely attached to the inner active drive cooling part and the outer passive drive heat dissipation part. The inner and outer magnetic heat transfer bridge part 5 is composed of a heat conductive and magnetic conductive layer 51, a heat conductive and non-magnetic conductive layer 52 and a directional heat conductive column 53.

[0050] The inner and outer magnetic insulation heat transfer bridge parts include a composite plate, which is formed by stacking heat-conducting and magnetic-conducting layers 51 (high magnetic and thermal conductivity materials) and heat-conducting non-magnetic-conducting layers 52 (materials with weak magnetic conductivity but strong thermal conductivity) alternately arranged in the radial direction. At the same time, a plurality of heat-conducting holes are distributed on the composite plate in the circumferential direction. The heat-conducting holes extend radially and penetrate the composite plate, and directional heat-conducting columns 53 are filled in the heat-conducting holes.

[0051] When the edge magnetic field of the motor enters the inner and outer magnetic isolation heat transfer bridge part 5, its magnetic circuit will give priority to the thermal and magnetic conductive layer 51, and some leakage magnetic flux is located in the thermal and non-magnetic conductive layer 52. As the radial position increases, the magnetic field strength will continue to decrease, and there is basically no magnetic field outside the inner and outer magnetic isolation heat transfer bridge part 5, which ensures the magnetic isolation environment of the external passive drive heat dissipation part 3. The directional heat conduction column 53 can not only directly transfer the heat of the internal active drive cooling part 2 to the external passive drive heat dissipation part 3 to achieve efficient heat transfer, but also partition the thermal and magnetic conductive layer 51 to reduce the eddy current loss of each layer.

[0052] Embodiment 2: In this embodiment, the external passively driven heat dissipation part can be cooled by an external cooling device.

[0053] In other embodiments, the structure of the heat dissipation pipe may also be changed or replaced to achieve cooling.

[0054] Embodiment three: This embodiment also discloses the composition of the magnetic fluid, which is composed of magnetic particles, a carrier liquid and an active agent. The selection and proportion of the three are within the routine experimental capabilities of those skilled in the art.

[0055] According to the current research progress on magnetic fluid: (1) Magnetic particles: Gd 5 Si 2 Ge 2 、MnAs、MnFeP 0.45 As 0.55 La(Fe x Si 1-x ) 13 , Mn 0.78 Zn 0.22 Fe 2 O 4 Any of the above.

[0056] (2) Base carrier liquid: any one of water, organic solvents (hydrocarbon-based carrier liquids), oils, phenols, etc.

[0057] (3) Surfactant: any one of oleic acid, etc.

[0058] Taking manganese-zinc ferrite magnetic fluid as an example, when the insulation requirements of the designed motor meet the hot spot temperature Below 220℃, the content of zinc is less than 0.3, the Curie temperature of manganese-zinc ferrite magnetic fluid Higher than the hot spot temperature of the motor (220℃) can meet the requirements.

[0059] For the preparation of manganese-zinc ferrite magnetic fluid, please refer to the literature: Yang Gang. Preparation and performance study of manganese-zinc ferrite magnetic fluid [D]. Nanjing University of Science and Technology, 2006.

[0060] The above embodiments are only used to illustrate rather than limit the technical solutions of the present invention. Although the present invention is described in detail with reference to the above embodiments, those skilled in the art should understand that the present invention can still be modified or replaced by equivalents. Any modification or partial replacement that does not depart from the spirit and scope of the present invention should be included in the scope of the claims of the present invention.

[0061] If the words "first", "second", etc. are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only to facilitate the description of the present invention and simplify the description. Unless otherwise stated, the above words have no special meaning.

[0062] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0063] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. An integrated self-driving cooling device for a power adaptive axial flux permanent magnet motor, characterized in that: It includes a cooling medium, an internal active drive cooling part and an external passive drive heat dissipation part; The internal active drive cooling part is used to absorb the heat generated by the heat generating structure on the stator side and the rotor side structure of the motor, as well as the heat conducted into the air gap; the internal active drive cooling part is a fan-shaped disk unit structure and is installed between the stator and rotor air gaps, and N fan-shaped disk unit structures are periodically distributed and arranged along the circumferential direction to form a circular disk structure; The main body of each sector disk unit structure is provided with an inlet section flow channel, an outlet section flow channel and m cooling elbows arranged in a radial direction, each cooling elbow extends in a circumferential direction, and the cooling elbow is located between the internal inlet section flow channel and the internal outlet section flow channel and is connected to the two; The external passively driven heat dissipation part is used to realize the demagnetization of the cooling medium magnetic fluid so as to cool it quickly; a symmetrical array of heat dissipation pipes is arranged in the main body of the external passively driven heat dissipation part, and the heat dissipation pipes have a heat dissipation pipe inlet and a heat dissipation pipe outlet; The inlet section flow channel of the internal active driving cooling part is connected to the outlet of the heat dissipation pipe of the external passive driving heat dissipation part, and the outlet section flow channel of the internal active driving cooling part is connected to the inlet of the heat dissipation pipe of the external passive driving heat dissipation part, thereby forming a cooling cycle; A gap is left in the radial direction between the internal active drive cooling part and the external passive drive heat dissipation part; The cooling medium is a magnetic fluid, which is filled in the pipelines of the internal active drive cooling part and the external passive drive heat dissipation part; the magnetic fluid utilizes the axial magnetic field of the axial flux permanent magnet motor to achieve self-driving and power adaptation.

2. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 1 is characterized in that: The outer diameter of the internal active drive cooling part is the same as the outer diameter of the stator side structure; one axial side of the internal active drive cooling part is in contact with the stator part, and the other axial side of the internal active drive cooling part is in clearance with the rotor part.

3. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 2 is characterized in that: The main body of the internal active drive cooling part is made of non-metallic material, and a flow channel is provided in the main body to form an inlet section flow channel, an outlet section flow channel and a cooling elbow; the inlet section flow channel and the outlet section flow channel are respectively extended and arranged in radial direction; The axial thickness of the internal active drive cooling section is positively correlated with the motor power.

4. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 3 is characterized in that: The number m of cooling bends arranged radially is the same as the number of turns of the stator winding; the m cooling bends are set with unequal diameters, and their diameters are positively correlated with the air gap magnetic field intensity, that is, the diameter of the bend in the middle is the largest, gradually decreasing toward the inside and outside, and does not exceed the axial reliability thickness of the internal active drive cooling part.

5. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 1 is characterized in that: The external passive drive heat dissipation part is an arc-shaped cylinder unit structure, which corresponds to the internal active drive cooling part one by one and has the same unit circumferential coverage angle; the external passive drive heat dissipation part is installed at the outer arc corresponding to the internal active drive cooling part, and N arc-shaped cylinder unit structures are periodically distributed and arranged along the circumferential direction and can be spliced ​​to form a cylindrical structure; The main body of the external passive drive heat dissipation part is made of a material with high thermal conductivity and low magnetic permeability, and a flow channel is opened in the main body to form a heat dissipation pipe; The heat dissipation pipe inlet and the heat dissipation pipe outlet of the external passive drive heat dissipation part are located at the central radial section of the internal active drive cooling part; the heat dissipation pipes of the external passive drive heat dissipation part are arranged in two groups axially symmetrically about the central radial section, and the axial length of the heat dissipation pipe is greater than the circumferential length; both groups of heat dissipation pipes are S-shaped connected; The radial thickness of the external passive drive heat sink is positively correlated with the motor power.

6. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 5 is characterized in that: The number of units N of the internal active drive cooling part / external passive drive heat dissipation part is consistent with the number of rotor poles; the circumferential span of the unit of the internal active drive cooling part is .

7. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 6, characterized in that: An inner magnetic suction interface is arranged at the outer side of the inlet section flow channel and the outlet section flow channel, and an outer magnetic suction interface is arranged at the inlet and outlet of the heat dissipation pipe; The inlet section flow channel of the internal active driven cooling part and the heat pipe outlet of the external passive driven heat dissipation part are connected through the matching internal magnetic attraction interface and the external magnetic attraction interface to form a sealed magnetic attraction interface part, and the outlet section flow channel of the internal active driven cooling part and the heat pipe inlet of the external passive driven heat dissipation part are connected through the matching internal magnetic attraction interface and the external magnetic attraction interface to form a sealed magnetic attraction interface part, thereby realizing a highly sealed cooling cycle.

8. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 7, characterized in that: The inner magnetic interface is located in the magnetic field, and has a lower flow pipe, which is an extension of the inlet section flow channel / outlet section flow channel of the internal active drive cooling part, and has a main coil on the outside of the lower flow pipe; a plurality of iron core bolts extending upward are arranged around the lower flow pipe, and a secondary coil is wound around the lower half of the iron core bolt, and the secondary coil is connected to the main coil; when the cooling medium passes through the lower flow pipe from bottom to top, it will induce current on the main coil and transmit it to the secondary coil, and the secondary coil makes the iron core bolt magnetic through electric excitation, and induces polarity at the upper end; The external magnetic interface has an upper circulation pipeline, which is an extension of the heat dissipation pipe inlet / heat dissipation pipe outlet of the external passively driven heat dissipation part. A card slot is provided at a position corresponding to the core bolt on the external magnetic interface, and a strong magnetic material with a polarity different from that of the core bolt end is provided inside the card slot; the card slot and the upper circulation pipeline are connected through the lower inlet hole and the upper outlet hole; The interface between the inner magnetic interface and the outer magnetic interface is composed of strong magnetic materials with different magnetic properties.

9. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 6, characterized in that: An arc-shaped area is formed at the gap between the internal active drive cooling part and the external passive drive heat dissipation part, and an inner and outer magnetic isolation heat transfer bridge part is provided at the arc-shaped area; The inner and outer magnetic isolation heat transfer bridge parts are closely fitted with the inner active drive cooling part and the outer passive drive heat dissipation part. The inner and outer magnetic isolation heat transfer bridge parts are used to isolate the internal air gap magnetic field and transfer the heat of the inner active drive cooling part to the outer passive drive heat dissipation part by heat conduction. The inner and outer magnetic insulation heat transfer bridge parts include a composite plate, which is formed by stacking heat-conducting and magnetic-conducting layers and heat-conducting non-magnetic-conducting layers alternately arranged in the radial direction. At the same time, there are multiple heat-conducting holes distributed in the circumferential direction on the composite plate. The heat-conducting holes extend radially and penetrate the composite plate, and directional heat-conducting columns are filled in the heat-conducting holes.

10. The power adaptive axial flux permanent magnet motor internal and external integrated self-driven cooling device according to claim 1, characterized in that: Curie temperature of the magnetic fluid used as cooling medium Higher than the hot spot temperature of the motor To avoid demagnetization at high temperature; the saturation magnetization intensity of the magnetic fluid is lower than the synthetic magnetic field intensity of the air gap to reduce the consumption of magnetic field energy.

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