High-integration-level bearingless axial magnetic flux motor and use method

Abstract

The invention discloses a high-integration-level bearingless axial magnetic flux motor and a using method, the motor comprises a motor shell and a rotor assembly and a stator assembly which are arranged in the motor shell, and the rotor assembly comprises a rotating shaft and a rotor disc fixed on the radial outer side of the rotating shaft; the rotating shaft is of a stepped shaft structure with the radial size gradually increased from the two ends to the middle, and a protection bearing matched with the rotating shaft is arranged in the motor shell and close to the end of the rotating shaft. The stator assemblies are arranged on the two sides of the disc face of the rotor disc in the motor shell in the axial direction of the rotating shaft, and each stator assembly comprises a stator iron core, a torque winding and a suspension winding, and the torque winding and the suspension winding are embedded in the stator iron core in parallel. The magnetic levitation function and the driving function are integrated, the axial space is greatly saved, the rigidity of the rotating shaft and the critical rotating speed of the system are improved, and the structure is extremely compact.

Description

Technical Field

[0001] This invention relates to the field of magnetic levitation motor technology, specifically to a highly integrated bearingless axial flux motor and its usage method. Background Technology

[0002] Magnetic levitation bearing motors use controllable electromagnetic force to stably levitate the rotor, eliminating the friction, wear, lubrication, and maintenance problems associated with mechanical bearings. They are commonly used in high-speed motors. Axial flux motors offer advantages such as high power density and high torque density. Applying magnetic levitation bearing technology to axial flux motors can improve their operating efficiency and further expand their application areas.

[0003] Traditional magnetic bearing motors have the following inherent defects: large axial space occupation and low rotor stiffness: the independent magnetic bearing system is installed at both ends of the motor shaft, which significantly increases the axial length of the motor, resulting in a decrease in shaft stiffness, a reduction in the system's critical speed, and a limitation on the motor's high-speed performance.

[0004] Magnetic levitation systems require independent stator and rotor structures, sensors, and power amplifiers, resulting in a large, complex, and costly motor system that reduces the system's power density and torque density.

[0005] Traditional control methods are insufficient in responding to dynamic operating conditions such as sudden load changes and external disturbances, affecting suspension stability. At the same time, the lack of intelligent fault early warning mechanism means that system reliability needs to be improved. When operating at high power density, the winding heats up in a concentrated manner, and the traditional external cooling method is inefficient, which restricts the continuous output capability of the motor. Summary of the Invention

[0006] Technical objective: To address the shortcomings of existing magnetic levitation motors, this invention discloses a highly integrated bearingless axial flux motor and its usage method.

[0007] Technical solution: To achieve the above technical objectives, the present invention adopts the following technical solution: A highly integrated bearingless axial flux motor includes: a motor housing and a rotor assembly and a stator assembly disposed within the motor housing. The rotor assembly includes a shaft and a rotor disk fixed radially outward from the shaft. The shaft is a stepped shaft structure with its radial dimension gradually increasing from both ends to the middle. A protective bearing that mates with the shaft is provided inside the motor housing near the end of the shaft. The stator assembly is disposed on both sides of the rotor disk surface within the motor housing along the axial direction of the shaft. The stator assembly includes a stator core and a torque winding and a suspension winding embedded in parallel on the stator core. The torque winding is located on the side near the air gap, and the suspension winding is located on the side near the yoke of the stator core.

[0008] Preferably, the rotor disk of the present invention has circumferentially alternating protruding iron poles and grooves on its disk surface. Permanent magnets are embedded in the grooves. The permanent magnets adopt an alternating pole design. All permanent magnets have the same polarity on the side near the air gap. The protruding iron poles between adjacent permanent magnets are magnetized under the action of the air gap magnetic field, exhibiting the opposite polarity to the adjacent permanent magnets, forming an equivalent magnetic pole structure with alternating N and S poles.

[0009] Preferably, displacement sensors for detecting rotor disk displacement are respectively provided in the radial and axial directions of the rotor disk inside the motor housing of the present invention; a rotor disk protective sleeve for fixing the embedded permanent magnet is provided on the outer periphery of the rotor disk, and the rotor disk is provided with annular protrusions that cooperate with the rotor disk protective sleeve; the displacement sensors are located corresponding to the surface of the rotor disk protective sleeve, and a detection reference surface is formed by the surface of the rotor disk protective sleeve.

[0010] Preferably, the radial clearance between the protective bearing and the rotating shaft is smaller than the detection clearance between the rotor disc sheath and the corresponding displacement sensor in the radial direction; the axial clearance between the end face of the protective bearing and the stepped surface of the rotor shaft is smaller than the air gap of the bearingless axial flux motor.

[0011] Preferably, the axial flux motor of the present invention is provided with an intelligent control system for controlling the operation of the rotor assembly, the intelligent control system including: The signal processing and fusion module is used to receive and process signals from multiple displacement sensors and calculate the six-degree-of-freedom pose information of the rotor through a data fusion algorithm. The core of the intelligent control algorithm is used to receive the pose information, compare it with the desired pose, and calculate the levitation force control command using the built-in control algorithm. A power drive module is used to drive the levitation winding according to the control command; The fault diagnosis and fault tolerance module is used to monitor the system status in real time and perform fault diagnosis and fault tolerance processing.

[0012] Preferably, the core of the intelligent control algorithm of the present invention employs at least one of model predictive control, adaptive control, fuzzy logic control, or neural network control.

[0013] Preferably, the flux motor of the present invention is connected to an integrated cooling system, which includes a microchannel network and an external circulation unit disposed outside the flux motor. The external circulation unit is connected to the microchannel network to form a circulation loop. The microchannel network is a closed flow channel pre-placed in the stator core yoke. The external circulation unit includes a coolant pump, a radiator, and a storage tank, and forms a forced circulation loop with the microchannel network through connecting pipelines. The cooling system uses an insulating coolant as the cooling medium.

[0014] This invention discloses a method for using a highly integrated bearingless axial flux motor, comprising the following steps: S1: Activate the intelligent control system and integrated cooling system, calibrate the displacement sensor, and set the desired floating posture of the rotating shaft; S2: The displacement sensor detects the radial and axial displacement signals of the rotor disk in real time and transmits the signals to the signal processing and fusion module; the signal processing and fusion module performs data fusion processing on the signals from multiple displacement sensors to calculate the real-time six-degree-of-freedom pose information of the rotor. S3: The core of the intelligent control algorithm receives the real-time pose information and compares it with the desired levitation pose. It then uses the built-in control algorithm to calculate the levitation force control command to compensate for the pose deviation. S4: The power drive module receives the levitation force control command, drives the levitation winding to pass in the corresponding current, generates the required controllable levitation force in the air gap magnetic field of the motor, and acts on the rotor assembly to make it stably levitate and maintain it in the desired posture. S5: During operation, the fault diagnosis and fault tolerance module monitors the status of the displacement sensor, winding and power drive module in real time; when a fault is diagnosed, the preset fault tolerance control strategy is executed, and when the rotor position exceeds the safety threshold, the protective bearing provides mechanical protection for the shaft. S6: During motor operation, active heat dissipation is achieved through the integrated cooling system. The coolant pump drives the insulating coolant to circulate in the loop formed by the microchannel network and the external circulation unit, carrying out the heat generated by the stator core and windings and dissipating it through the radiator.

[0015] Beneficial Effects: The highly integrated bearingless axial flux motor and its usage method disclosed in this invention have the following beneficial effects: 1. This invention integrates magnetic levitation and driving functions by embedding the suspension winding and torque winding together into the stator core, which greatly saves axial space, improves shaft stiffness and system critical speed, and has an extremely compact structure.

[0016] 2. The rotor adopts an alternating pole design of "permanent magnet + iron pole". While ensuring the number of magnetic poles, the amount of permanent magnets used is reduced by about 50%, which significantly reduces material costs and improves the torque density of the motor. The reduction of system components also reduces the overall cost and volume.

[0017] 3. This invention introduces an intelligent control system with multi-sensor fusion, intelligent algorithms and fault diagnosis functions, which significantly improves the operating stability, response speed and reliability of the motor under dynamic load and complex working conditions.

[0018] 4. This invention uses microchannels built into the stator and insulating coolant to directly and efficiently dissipate heat from the core components (stator core and windings), solving the heat dissipation problem caused by highly integrated motors, allowing the motor to operate continuously at higher power and extending its service life. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 This is a schematic diagram of the magnetic flux motor structure of the present invention; Figure 2 This is a structural diagram of the rotor disk of the present invention; Figure 3 This is a structural diagram of the stator assembly of the present invention; Figure 4 This is a schematic diagram of the intelligent control system of the present invention; Among them, 1-motor housing, 2-shaft, 3-rotor disk, 4-protective bearing, 5-stator core, 6-torque winding, 7-floating winding, 8-protruding iron pole, 9-permanent magnet, 10-displacement sensor, 11-rotor disk protective sleeve, 12-annular protrusion, 13-signal processing and fusion module, 14-intelligent control algorithm core, 15-power drive module, 16-fault diagnosis and fault tolerance module, 17-microchannel network. Detailed Implementation

[0021] Reference will now be made in detail to embodiments of the present disclosure, one or more of which are set forth herein. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. Rather, the following description provides convenient illustrations for implementing exemplary embodiments of the present disclosure. Indeed, it will be apparent to those skilled in the art that various modifications and variations can be made to the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0022] like Figures 1-4 As shown, the present invention provides a highly integrated bearingless axial flux motor, the core of which lies in the high integration of torque generation and active levitation function into a single motor structure, and the realization of stable levitation and precise control of the rotor through an intelligent control system. The bearingless specifically refers to a bearingless levitation motor.

[0023] Reference Figure 1The motor includes main components such as a motor housing 1, a rotating shaft 2, a rotor disc 3, protective bearings 4, a stator core 5, torque windings 6, and suspension windings 7. The rotating shaft 2, as the core support of the rotor, is designed as a stepped shaft structure with radial dimensions gradually increasing from both ends to the middle. This structure not only enhances the rigidity of the rotating shaft, which is beneficial for increasing the critical speed, but also provides a precise mating reference surface for axial positioning and protecting the bearings 4. Protective bearings 4 are installed on the motor housing 1 near both ends of the rotating shaft 2. These bearings do not contact the rotating shaft 2 during normal suspended operation of the motor, and only provide mechanical protection in case of rotor drop during startup, shutdown, or malfunction.

[0024] The rotor disk 3 is fixed to the radial outer side of the rotating shaft 2. To ensure stable installation of the rotor disk 3, as follows: Figure 1 As shown, the rotating shaft 2 of the present invention forms a stepped surface that supports the rotor disk 3 by changing its diameter at the mating point with the rotor disk 3, thereby ensuring stable axial support for the rotor disk 3 in the installation orientation shown in the figure.

[0025] The rotor disk 3 of this invention has alternating protruding iron poles 8 and grooves distributed circumferentially on its surface, with permanent magnets 9 of alternating pole design embedded in the grooves. Specifically, all permanent magnets 9 on the same surface of the rotor disk 3 have the same polarity (e.g., all are N poles) on the side closest to their corresponding air gap, where the air gap is the axial gap between the rotor and the stator. The protruding iron poles 8 between adjacent permanent magnets 9 are magnetized under the influence of the air gap magnetic field, exhibiting the opposite polarity (i.e., S pole) to the adjacent permanent magnets, thus forming an equivalent alternating N / S pole magnetic pole structure on the rotor disk surface. This design simplifies the magnetization process of the permanent magnets and improves the air gap magnetic flux density and torque density.

[0026] like Figure 1 and Figure 3 As shown, the present invention comprises two stator assemblies, which are respectively disposed on the outer sides of the two disks of the rotor disk 3 along the axial direction of the shaft 2, and are embedded and fixed by the end cap at the end of the motor housing 1. Each stator assembly includes a stator core 5 and a torque winding 6 and a suspension winding 7 embedded thereon. The winding layout is optimized: the torque winding 6 is located closer to the air gap to efficiently generate driving torque; the suspension winding 7 is located closer to the yoke of the stator core to generate controllable levitation force. This layered layout effectively utilizes space and reduces coupling interference between the two magnetic fields.

[0027] To ensure the stability and accuracy of rotor suspension, multiple displacement sensors 10 (e.g., eddy current sensors) are installed in the motor housing 1 along the radial and axial directions of the rotor disk 3. These sensors are used to detect the displacement of the rotor disk in real time. Sensors that detect radial displacement are designated as radial displacement sensors, and those that detect axial displacement are designated as axial displacement sensors. Multiple sets of these sensors can be configured. To protect the permanent magnet 9 and provide a smooth and stable detection reference surface, a non-magnetic rotor disk protective sleeve 11 is installed around the outer periphery of the rotor disk 3. The edge of the rotor disk 3 has an annular protrusion 12 that mates with the rotor disk protective sleeve 11 for axial limiting and reinforcement. The detection head of the displacement sensor 10 faces the surface of the rotor disk protective sleeve 11, forming a high-precision displacement detection reference. Compared to directly inspecting the rotor, the surface of the rotor disk protective sleeve 11 is easier to process to a high precision, thereby reducing the surface processing requirements of the rotor and ensuring the accuracy of the displacement monitoring results.

[0028] To protect the rotor, the radial clearance between the protective bearing 4 and the shaft 2 is set to be smaller than the detection air gap between the surface of the rotor disc protective sleeve 11 and the corresponding radial displacement sensor 10 probe. Similarly, the axial clearance between the end face of the protective bearing 4 and the stepped surface of the shaft 2 is set to be smaller than the electromagnetic air gap during normal motor operation. This design ensures that when the rotor experiences significant misalignment, the protective bearing 4 can contact the stator before the rotor, providing effective mechanical protection and improving structural safety.

[0029] The axial flux motor is equipped with an intelligent control system for controlling the operation of the rotor assembly. The intelligent control system includes: The signal processing and fusion module 13 is used to receive and process signals from multiple displacement sensors and calculate the six-degree-of-freedom pose information of the rotor through a data fusion algorithm; the data fusion algorithm may be an algorithm based on coordinate system transformation.

[0030] The core of the intelligent control algorithm 14 is used to receive the pose information, compare it with the desired pose, and calculate the levitation force control command using the built-in control algorithm. The control algorithm includes at least one of model predictive control, adaptive control, fuzzy logic control or neural network control, which can quickly and accurately calculate the levitation force control command required to eliminate pose deviation.

[0031] The power drive module 15 is used to drive the suspension winding according to the control command; it is usually a multiphase inverter, which receives the control command from the intelligent control algorithm core 14 and drives the suspension winding 7 to pass the corresponding current, thereby generating a precise and controllable electromagnetic force in the air gap magnetic field and realizing the active adjustment of the rotor position.

[0032] The fault diagnosis and fault tolerance module 16 is used to monitor the system status in real time and perform fault diagnosis and fault tolerance processing.

[0033] The system monitors system parameters in real time, including displacement sensors, winding currents, and power device status. Once a fault is diagnosed, such as sensor failure or winding short circuit, a preset fault-tolerant strategy can be triggered, such as switching to a backup sensor or adjusting control algorithm parameters, to maintain system operation or safely shut down the system.

[0034] In addition, the motor is connected to a highly efficient integrated cooling system. This system includes a microchannel network 17 pre-installed within the stator core yoke and an external circulation unit located outside the motor. The microchannel network 17 is a precision-machined closed flow channel, the flow path of which needs to be optimized through thermal simulation to ensure coverage of the main heat-generating areas. The microchannels can be formed on silicon steel sheets through etching, fine stamping, or other processes before the core laminations are stacked, forming complete channels after stacking; or the core with channels can be manufactured as a single unit using technologies such as 3D printing. The interface between the stator core 6 and the motor housing 1, as well as the external pipeline connections, are reliably sealed using O-rings or sealant to prevent coolant leakage. The external circulation unit includes a coolant pump, radiator, and reservoir, which form a forced circulation loop with the microchannel network 17 through connecting pipelines. The cooling medium is an insulating coolant (such as mineral oil, fluorinated liquid, etc.), which can directly exchange heat with the stator core and windings, efficiently removing heat and ensuring that the temperature rise of the motor, especially the windings and core, is within a safe range under high temperature and high power density operation.

[0035] The method of using the highly integrated bearingless axial flux motor described in this invention mainly includes the following steps: S1: Start the intelligent control system and integrated cooling system. After the system is powered on, first perform zero-point calibration on displacement sensor 10, and set the desired floating pose (usually the center position) of rotating shaft 2 in the control system.

[0036] S2: During motor operation, multiple displacement sensors 10 continuously monitor the radial and axial displacement signals of the rotor disk 3 in real time and transmit these signals to the signal processing and fusion module 13. This module performs data fusion processing on the multiple signals to accurately calculate the real-time six-degree-of-freedom pose information of the rotor.

[0037] S3: The core of the intelligent control algorithm 14 receives real-time pose information and compares it with the desired levitation pose to obtain the pose error. Using built-in advanced control algorithms (such as MPC), it quickly calculates the magnitude and direction of the levitation force required to compensate for the pose deviation, and then generates levitation force control commands.

[0038] S4: The power drive module 15 receives the levitation force control command and drives the levitation winding 7 to pass a precisely calculated current, thereby generating the required controllable levitation force in the motor air gap magnetic field. This force acts on the rotor assembly, dynamically adjusting its position to ensure stable levitation and precise maintenance in the desired posture.

[0039] S5: Throughout the operation, the fault diagnosis and fault tolerance module 16 monitors the critical status of the system in real time. When a fault is diagnosed, the preset fault tolerance control strategy is immediately executed. If the fault causes the rotor position to exceed the safety threshold, the protection bearing 4 will intervene, contacting the shaft 2 to prevent the rotor from colliding with the stator, providing final mechanical protection.

[0040] S6: During motor operation, the integrated cooling system operates continuously. The coolant pump drives the insulating coolant to circulate in a closed loop formed by the microchannel network 17 and the external circulation unit. As the coolant flows through the stator core, it fully absorbs the heat generated by the stator core and windings, and then flows to the external radiator to dissipate the heat into the environment, thereby ensuring the long-term stable operation of the motor.

[0041] By using the flux motor structure of the present invention, the axial length, volume and weight of the system are significantly reduced, and extremely high power density and torque density are achieved. It is particularly suitable for space-constrained applications. In conjunction with the detection surface of the rotor disk protective sleeve 11 and the corresponding displacement sensor, high-precision detection of rotor displacement is achieved, providing a reliable foundation for high-precision and stable control of rotor suspension.

[0042] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A highly integrated bearingless axial flux motor, characterized in that, include: The motor housing (1) includes a rotor assembly and a stator assembly disposed within the motor housing (1). The rotor assembly includes a rotating shaft (2) and a rotor disk (3) fixed radially outside the rotating shaft (2). The rotating shaft (2) is a stepped shaft structure with radial dimensions gradually increasing from both ends to the middle. The motor housing (1) contains a protective bearing (4) that cooperates with the rotating shaft (2) near the end of the rotating shaft. The stator assembly is disposed on both sides of the disk surface of the rotor disk (3) within the motor housing (1) along the axial direction of the rotating shaft (2). The stator assembly includes a stator core (5) and a torque winding (6) and a suspension winding (7) embedded in parallel on the stator core (5). The torque winding (6) is located on the side near the air gap, and the suspension winding (7) is located on the side near the yoke of the stator core.

2. The highly integrated bearingless axial flux motor according to claim 1, characterized in that, The rotor disk (3) has circumferentially alternating protruding iron poles (8) and grooves on its disk surface. Permanent magnets (9) are embedded in the grooves. The permanent magnets (9) adopt an alternating pole design. All permanent magnets (9) have the same polarity on the side closest to the corresponding air gap. The protruding iron poles (8) between adjacent permanent magnets (9) are magnetized under the action of the air gap magnetic field, exhibiting the opposite polarity to the adjacent permanent magnets (9), forming an equivalent magnetic pole structure with alternating N and N poles.

3. The highly integrated bearingless axial flux motor according to claim 2, characterized in that, The motor housing (1) has displacement sensors (10) installed in the radial and axial directions of the rotor disk (3) to detect the displacement of the rotor disk. The rotor disk (3) has a rotor disk protective sleeve (11) installed on its outer periphery to fix the embedded permanent magnet (9). The rotor disk (3) has an annular protrusion (12) that cooperates with the rotor disk protective sleeve (11). The displacement sensor (10) is located on the surface of the rotor disk protective sleeve (11) and a detection reference surface is formed by the surface of the rotor disk (3) protective sleeve (11).

4. A highly integrated bearingless axial flux motor according to claim 3, characterized in that, The radial clearance between the protective bearing (4) and the rotating shaft (1) is smaller than the detection clearance between the rotor disc sheath (11) and the corresponding displacement sensor in the radial direction; the axial clearance between the end face of the protective bearing (4) and the stepped surface of the rotor shaft is smaller than the air gap of the bearingless axial flux motor.

5. A highly integrated bearingless axial flux motor according to claim 3, characterized in that, The axial flux motor is equipped with an intelligent control system for controlling the operation of the rotor assembly. The intelligent control system includes: The signal processing and fusion module (13) is used to receive and process signals from multiple displacement sensors and calculate the six-degree-of-freedom pose information of the rotor through a data fusion algorithm. The core of the intelligent control algorithm (14) is used to receive the pose information, compare it with the desired pose, and calculate the suspension force control command using the built-in control algorithm. The power drive module (15) is used to drive the suspension winding according to the control command; The fault diagnosis and fault tolerance module (16) is used to monitor the system status in real time and perform fault diagnosis and fault tolerance processing.

6. A highly integrated bearingless axial flux motor according to claim 4, characterized in that, The core of the intelligent control algorithm (14) employs a control algorithm that includes at least one of model predictive control, adaptive control, fuzzy logic control, or neural network control.

7. A highly integrated bearingless axial flux motor according to claim 1, characterized in that, The flux motor is connected to an integrated cooling system, which includes a microchannel network (17) and an external circulation unit located outside the flux motor. The external circulation unit is connected to the microchannel network (17) to form a circulation loop. The microchannel network (17) is a closed flow channel pre-placed in the stator core yoke. The external circulation unit includes a coolant pump, a radiator and a liquid storage tank, which form a forced circulation loop with the microchannel network (17) through connecting pipelines. The cooling system uses an insulating coolant as the cooling medium.

8. A method of using a highly integrated bearingless axial flux motor as described in any one of claims 1-7, characterized in that, Includes the following steps: S1: Activate the intelligent control system and integrated cooling system, calibrate the displacement sensor, and set the desired floating posture of the rotating shaft; S2: The displacement sensor detects the radial and axial displacement signals of the rotor disk in real time and transmits the signals to the signal processing and fusion module; the signal processing and fusion module performs data fusion processing on the signals from multiple displacement sensors to calculate the real-time six-degree-of-freedom pose information of the rotor. S3: The core of the intelligent control algorithm receives the real-time pose information and compares it with the desired levitation pose. It then uses the built-in control algorithm to calculate the levitation force control command to compensate for the pose deviation. S4: The power drive module receives the levitation force control command, drives the levitation winding to pass in the corresponding current, generates the required controllable levitation force in the air gap magnetic field of the motor, and acts on the rotor assembly to make it stably levitate and maintain it in the desired posture. S5: During operation, the fault diagnosis and fault tolerance module monitors the status of the displacement sensor, winding and power drive module in real time; when a fault is diagnosed, the preset fault tolerance control strategy is executed, and when the rotor position exceeds the safety threshold, the protective bearing provides mechanical protection for the shaft. S6: During motor operation, active heat dissipation is achieved through the integrated cooling system. The coolant pump drives the insulating coolant to circulate in the loop formed by the microchannel network and the external circulation unit, carrying out the heat generated by the stator core and windings and dissipating it through the radiator.

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