Novel axial-radial composite positioning bearingless magnetic flux permanent magnet motor

Abstract

The utility model discloses a novel axial-radial composite positioning bearingless magnetic flux permanent magnet motor, which comprises a rotor, a permanent magnet and a stator which are sequentially arranged from inside to outside, the permanent magnet is attached to the surface of the rotor, a stator gap is reserved between the stator and the rotor, eight grooves are equally cut in the inner wall of the stator in the circumferential direction, torque windings and suspension force windings are wound on tooth parts between the adjacent grooves through distributed windings, capacitive displacement sensors are installed in the tooth parts, and electromagnetic compensation coils are arranged on the outer wall of the stator. And the capacitive displacement sensor is in closed-loop connection with the winding and the electromagnetic compensation coil. According to the utility model, omnibearing monitoring is carried out on the X, Y and Z directions when the rotor rotates and suspends in the motor, abnormal phenomena are fed back and timely adjusted, and the problems of instability and insufficient magnetic field intensity generated by the rotor under a high-intensity working condition are effectively regulated and controlled. And the demagnetization risk and the performance attenuation speed of the permanent magnet attached to the rotor in the motor are also obviously reduced.

Description

Technical Field

[0001] This utility model relates to the field of bearingless motor technology, specifically to a bearingless flux permanent magnet motor that achieves strong magnetic field anti-interference capability through axial-radial composite positioning, timely and accurate rotor positioning, and timely sensing and adjustment of abnormal phenomena; it is particularly suitable for UAV power systems that require unique structural advantages and high load adaptability, medical robot joints and MRI and other medical equipment, semiconductor manufacturing equipment and aerospace fields. Background Technology

[0002] Bearingless motors achieve rotor levitation control by installing windings on the stator that generate radial forces. These windings, by controlling the direction and magnitude of the current, produce electromagnetic forces related to the rotor's position. This eliminates the problems of high frictional losses, high maintenance costs, and high vibration and noise associated with mechanical bearings supporting the rotor in traditional bearing motors. However, current technology is still limited in the following aspects:

[0003] 1. Although relying on the single levitation force technology and decoupling control of the rotor enables the rotor to achieve stable levitation and rotation under compromise working conditions and effectively suppresses the rotor's back-and-forth movement in the axial direction, the motor may still experience insufficient axial stability under extreme load working conditions, which may lead to instability and loss of rotor control.

[0004] 2. In high-intensity working scenarios, the sensors in the motor can usually only monitor the rotor's movement trajectory in a single direction, which cannot cover the rotor's full degree of freedom of movement. Furthermore, when the motor is running, it generates a strong magnetic field, which can easily interfere with the sensor's signal, causing the sensor to malfunction and lose feedback. This can lead to incorrect judgments about the rotor, resulting in rotor collisions or shutdowns.

[0005] 3. The concentrated arrangement of windings on the stator of the motor can easily lead to severe harmonic losses, significant motor temperature rise and magnetic circuit saturation, which significantly increases the risk of demagnetization of permanent magnets in the motor and the rate of performance degradation. Utility Model Content

[0006] The purpose of this invention is to provide a novel integrated switch-type bearingless permanent magnet synchronous motor with high heat dissipation, which solves the problems of insufficient heat dissipation, complex structure, and difficult control in the prior art.

[0007] The specific plan is as follows:

[0008] The purpose of this invention is to provide a bearingless flux permanent magnet motor with axial-radial composite positioning, which solves the problems of rotor instability caused by insufficient axial stability, the occurrence of blind spots in radial sensor monitoring, significant stator temperature rise, insufficient magnetic field strength under high-intensity working conditions, and severe interference of external factors on the magnetic field in the prior art.

[0009] The specific plan is as follows:

[0010] A novel bearingless flux permanent magnet motor with axial-radial composite positioning includes a rotor, a permanent magnet, and a stator arranged sequentially from the inside to the outside. The permanent magnet is attached to the surface of the rotor, and a stator gap is left between the stator and the rotor. The inner wall of the stator is cut with eight grooves equally divided along the circumferential direction. Torque windings and levitation force windings are wound on the teeth between adjacent grooves using distributed windings. Capacitive displacement sensors are installed in the teeth. An electromagnetic compensation coil is provided on the outer wall of the stator. The capacitive displacement sensors are connected in a closed loop with the windings and the electromagnetic compensation coil.

[0011] Furthermore, a bushing spring housing assembly is installed at the end of the rotor, a stator junction box is installed at the upper end of the motor, a motor base is installed at the bottom, and heat dissipation holes are evenly distributed on both ends.

[0012] Furthermore, the bushing spring housing assembly includes a disc spring assembly, a shock-absorbing pad, and a bushing, with the shock-absorbing pad placed inside the bushing and the disc spring assembly placed outside the bushing.

[0013] Furthermore, the capacitive displacement sensor is used to perform omnidirectional control of the rotor in the X, Y, and Z directions during operation, and transmits signals to the windings and electromagnetic compensation coils through a closed-loop circuit.

[0014] Furthermore, the permanent magnets are arranged in a non-uniform Halbach array manner.

[0015] The following design concept was adopted in this application:

[0016] 1. Axial positioning mechanism: A bushing spring housing assembly is set at one protruding end of the motor rotor, and a fixed disc spring assembly is set inside the bushing. When the motor is under high working intensity, if the rotor moves forward, the disc spring assembly will be compressed axially by the rotor, thereby generating a repulsive force on the rotor. Under the action of the repulsive force, the rotor is driven back to its original working area.

[0017] 2. Radial monitoring and suspension system: The stator is evenly cut into 8 slots, and eight sets of capacitive displacement sensors are installed on the convex parts after the stator is cut to monitor the rotational displacement of the rotor in the X, Y, and Z directions in all directions. The windings on the stator are distributed and electromagnetic compensation coils are installed on the stator.

[0018] 3. Magnetic flux generation and path optimization design: A magnetic field is generated by attaching permanent magnets to the rotor surface. The permanent magnets adopt a combination of axial and radial magnetization and are arranged in a non-uniform Halbach array to form a composite magnetic circuit, and sufficient gap is left between the rotor and the stator.

[0019] The technical advantages of this utility model are as follows:

[0020] 1. The housing assembly with added bushing and disc spring group can effectively suppress the rotor's axial back-and-forth movement under high load conditions, accelerate the motor's response speed, and make the motor less prone to instability under extreme working conditions.

[0021] 2. Monitor the rotor's motion and displacement comprehensively during operation to obtain timely information about the rotor's status and adjust its orientation accordingly.

[0022] 3. It improves the torque power density per unit volume and the energy efficiency of the system, accelerates the sensor's response to rotor suspension, and is better able to adapt to external environmental disturbances to the magnetic field under high-frequency, high-intensity working conditions.

[0023] 4. By changing the magnetic field strength level generated by the permanent magnet, the air gap magnetic field between the rotor and the permanent magnet is adjusted, thereby achieving variable magnetic flux, which enables the motor to maintain high efficiency and stable operation at different operating points.

[0024] 5. It can greatly enhance the magnetic field strength in a specific direction while reducing interference to surrounding sensitive electronic components. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the external appearance of a novel axial-radial bearingless flux permanent magnet motor according to this utility model.

[0026] Figure 2 This is a schematic diagram of the structure of the bushing spring housing assembly added to the outer end of the rotor of a novel axial-radial bearingless flux permanent magnet motor according to this utility model.

[0027] Figure 3 This is a schematic diagram of the structure of a novel axial-radial bearingless flux permanent magnet motor, in which permanent magnets are attached to the rotor surface in a non-uniform Halbach array arrangement.

[0028] Figure 4 This is a schematic diagram of any one of the eight displacement sensors and electromagnetic compensation coils added to the stator of a novel axial-radial bearingless flux permanent magnet motor according to this utility model.

[0029] Figure 5This utility model discloses a circuit diagram showing the connection of a displacement sensor and an electromagnetic compensation coil on the stator of a novel axial-radial bearingless flux permanent magnet motor.

[0030] List of reference numerals in the attached diagram:

[0031] 1-Stator junction box; 2-Shaft sleeve spring housing assembly; 3-Heat dissipation hole; 4-Motor base; 5-Permanent magnet; 6-Stator clearance; 7-Rotor; 8-Torque winding; 9-Suspension winding; 10-Capacitive displacement sensor; 11-Electromagnetic compensation coil; 12-Stator; 13-Sensor; 21-Disc spring assembly; 22-Shock damping pad; 23-Shaft sleeve. Detailed Implementation

[0032] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 The diagram shows the external structure of the motor of this utility model. The rotor 7 iron core is supported and stabilized by magnetic field force and radial force generated by the permanent magnet 5, electromagnetic compensation coil 11 and three-phase winding. The stator junction box 1 is installed on the top of the motor to connect the power cord, ensuring normal operation of the motor and making the connection of the power cord more convenient. This eliminates the need for users to directly contact the internal terminals of the motor, effectively reducing the impact of the external environment on the motor, thereby extending the service life of the motor, reducing the difficulty of operation and reducing safety hazards. The motor base 4 is installed at the bottom of the motor to support the motor body, press and fix the motor, ensure stable operation of the motor, and reduce the vibration amplitude of the motor. Holes are drilled at both ends of the motor to form heat dissipation holes 3, which accelerate the dissipation and conduction of heat generated during motor operation.

[0034] like Figure 2The diagram shows the structure of the bushing spring housing assembly 2 added to the rotor 7 at the outer end of the motor according to this invention. This assembly is welded to the end of the motor rotor 7, so that one end of the rotor 7 is contained within it. When the motor operates under high load conditions, the rotor 7 may move axially. When the rotor 7 moves into the damping pad 22 of this assembly, the disc spring assembly 21 under the damping pad 22 is compressed by the rotor 7. The disc spring assembly 21 thus generates a repulsive force on the rotor 7 opposite to the axial movement, forcing the rotor 7 back to its original working environment. The damping pad 22 is located above the disc spring assembly 21. The damping pad 22 achieves vibration reduction through elastic deformation and damping characteristics. When impacted by the rotor 7, the material molecular chains of the damping pad 22 undergo friction and internal wear, converting vibration energy into heat energy for dissipation. This effectively transfers the energy generated when the rotor 7 moves axially to the disc spring assembly 21, minimizing the impact on the rotor. Energy loss when rotor 7 contacts the components; the stiffness of disc spring assembly 21 is not constant, but dynamically adjusted with the displacement of rotor 7. In the initial loading stage, disc spring assembly 21 exhibits low stiffness, requiring only a small force to produce a large displacement; as the displacement of rotor 7 increases, the axial force becomes larger, and the stiffness of disc spring assembly 21 gradually increases, requiring a larger force to achieve additional displacement. When disc spring assembly 21 is compressed by rotor 7, it stores a small amount of mechanical energy. When the external force of rotor 7 on disc spring assembly 21 is removed, disc spring assembly 21 can quickly return to its initial shape by elastic restoring force and release the stored energy; the bushing 23 is attached to the outside of disc spring assembly 21 and rotor 7 by spiral clamping, which can effectively prevent dust, moisture and other external environmental factors from affecting disc spring assembly 21 and rotor 7, thereby extending the service life of disc spring assembly 21 and motor.

[0035] like Figure 3 The diagram shows the internal structure of the motor with a non-uniform Halbach array arrangement of permanent magnets 5 attached to the outside of the rotor 7. The permanent magnets 5 are arranged in a non-uniform Halbach array, which arranges the permanent magnets 5 with different magnetization directions according to a specific pattern. This allows the magnetic field generated by the permanent magnets 5 to converge and strengthen on one side while canceling it out on the other, forming a strong magnetic field on one side. This allows for timely adjustment of the magnetic field required by the rotor 7, enabling the rotor 7 to obtain sufficient levitation force to support its stable levitation under high load conditions. A sufficiently large stator gap 6 is left between the stator 12 and the permanent magnets 5, ensuring that the rotor 7 can rotate freely inside the stator 12, avoiding direct collisions that could affect the normal operation of the motor. The appropriate size of the stator gap 6 allows for variable magnetic flux and reduces magnetic reluctance, excitation loss, and increased excitation current. It also effectively avoids the increase of harmonic magnetic fields, magnetic field losses, and noise generation, improving the power factor and efficiency of the motor.

[0036] like Figure 4 The diagram shows any one of the eight sets of capacitive displacement sensors 10 and the electromagnetic compensation coil 11 added to the stator 12 in this invention. The stator 12 is divided into eight equal parts, and the levitation winding 9 and torque winding 8 are distributed in a ring shape, evenly distributed on the eight protrusions of the stator 12 to quickly dissipate the heat generated by the windings, reduce harmonic losses, optimize the control performance of the magnetic field, and reduce the risk of demagnetization and performance degradation of the permanent magnet 5. Eight capacitive displacement sensors 10 are installed on the eight protrusions of the stator 12 to monitor the position and displacement of the rotor 7 in the X, Y, and Z directions of levitation and rotation inside the stator 12 in all directions, and to detect the displacement in real time. Real-time sensing and precise position feedback based on monitoring data enable timely adjustment of control signals. This allows the control system to more accurately adjust the motor's operating state, ensuring the motor runs along the expected trajectory. This effectively prevents contact between the rotor 7 and stator 12, reducing mechanical wear and malfunctions, improving system stability and reliability, enhancing control precision, reducing maintenance requirements, and extending equipment life. An electromagnetic compensation coil 11 is connected to the stator 12 to further control the system's output current during rotor 7 operation. When the system output current becomes abnormal, a Lorentz force opposite to the rotor 7's offset direction is generated, causing the rotor 7 to return to the predetermined displacement trajectory.

[0037] like Figure 5 The diagram shows the connection circuit of any set of capacitive displacement sensors 10 and electromagnetic compensation coils 11 added to the stator 12 in this invention in the motor. The capacitive displacement sensor 10 monitors the rotor 7 in real time through two sets of sensors 13 at the front end of the device, and converts the monitoring results into electrical signals that are transmitted to the torque winding 8, the levitation force winding 9 connected to the middle of the capacitive displacement sensor 10, and the electromagnetic compensation coil 11 connected to the rear. This enables the system to quickly adjust the required levitation force, radial force, and magnetic field magnitude of the rotor 7, and to better position and control the rotor 7 in the radial direction.

[0038] The technical means disclosed in this utility model are not limited to the above-described implementation scheme, but also include technical solutions that combine any of the above technical features.

Claims

1. A novel bearingless flux permanent magnet motor with axial-radial composite positioning, characterized in that, The stator includes a rotor (7), a permanent magnet (5), and a stator (12) arranged sequentially from the inside to the outside. The permanent magnet (5) is attached to the surface of the rotor (7), and a stator gap (6) is left between the stator (12) and the rotor (7). The inner wall of the stator (12) is cut with 8 grooves in equal sections along the circumferential direction. The teeth between adjacent grooves are wound with distributed windings of torque windings (8) and levitation windings (9). A capacitive displacement sensor (10) is installed in the teeth. An electromagnetic compensation coil (11) is provided on the outer wall of the stator (12). The capacitive displacement sensor (10) is connected in a closed loop with the windings and the electromagnetic compensation coil (11).

2. The novel bearingless flux permanent magnet motor with axial-radial composite positioning according to claim 1, characterized in that, The rotor (7) is equipped with a bushing spring housing assembly (2) at its end, a stator junction box (1) is installed at the top of the motor, a motor base (4) is installed at the bottom, and heat dissipation holes (3) are evenly distributed on both ends.

3. A novel bearingless flux permanent magnet motor with axial-radial composite positioning according to claim 2, characterized in that, The bushing spring housing assembly (2) includes a disc spring assembly (21), a shock-absorbing pad (22), and a bushing (23). The shock-absorbing pad (22) is placed inside the bushing (23), and the disc spring assembly (21) is placed outside the bushing (23).

4. A novel bearingless flux permanent magnet motor with axial-radial composite positioning according to claim 1, characterized in that, The capacitive displacement sensor (10) is used to control the rotor in all directions (X, Y, Z) during operation and transmits signals to the windings and electromagnetic compensation coils (11) through a closed-loop circuit.

5. A novel bearingless flux permanent magnet motor with axial-radial composite positioning according to claim 1, characterized in that, The permanent magnets (5) are arranged in a non-uniform Halbach array.

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