Method for controlling a bearingless motor, control circuit and bearingless motor

Abstract

The application provides a bearingless motor control method, a control circuit and a bearingless motor. The bearingless motor control method comprises the following steps: charging an energy storage component; detecting an offset value of an actual rotation center line of a rotor relative to a set rotation center line; if the offset value of the rotor is less than 20 mu m, the energy storage component continues to be charged; if the offset value of the rotor is greater than or equal to 20 mu m, the energy storage component is discharged to supply power to a damping coil, the damping coil generates a bias magnetic field, and the bias magnetic field is subjected to the magnetic field of a stator to make the rotor return to the set rotation center line. If the offset value of the rotor is less than 20 mu m, the position of the rotor does not produce a large offset, and the operation of the bearingless motor is not affected. If the offset value of the rotor is greater than 20 mu m, the damping coil generates a bias magnetic field, and a magnetic pulling force is generated under the action of the magnetic field of the stator to send the rotor back to the set rotation center line, effectively solving the problem of unstable suspension of the rotor in the operation process of the bearingless motor.

Description

Technical Field

[0001] This invention relates to the field of bearingless motor technology, and more specifically, to a bearingless motor control method, control circuit, and bearingless motor. Background Technology

[0002] Currently, bearingless motors utilize windings wound on the stator to provide levitation force and energy, enabling the rotor to levitate and rotate, thus achieving bearingless operation. For example, patent CN115514128A discloses a bearingless high-speed motor structure, which, like traditional high-speed motors, uses a set of windings to provide stable levitation force and energy, allowing the rotor to levitate and rotate. However, if the rotor is biased and cannot return to its correct position, it can easily lead to rotor levitation instability. Summary of the Invention

[0003] This invention provides a bearingless motor control method, control circuit, and bearingless motor to solve the problem of rotor suspension instability in existing bearingless motors.

[0004] To address the aforementioned problems, according to one aspect of the present invention, a bearingless motor control method is provided. The bearingless motor includes a stator, a rotor, an energy storage assembly, and a damping coil. The bearingless motor control method includes: S10: Charge the energy storage components; S20: Detect the offset value of the actual rotation center line of the rotor relative to the set rotation center line; S30: If the rotor offset is less than 20μm, the energy storage component continues to charge; if the rotor offset is greater than or equal to 20μm, the energy storage component discharges to supply power to the damping coil. The damping coil generates a bias magnetic field, which is subjected to the magnetic field of the stator, causing the rotor to return to the set rotation center line.

[0005] Furthermore, the energy storage assembly is disposed within the rotor, and S10 also includes: As the rotor rotates, the energy storage component generates an induced current under the influence of the stator's magnetic field, which charges the energy storage component.

[0006] Furthermore, the bearingless motor also includes sensors, and S20 also includes: The sensor detects the offset of the rotor's actual rotation center line relative to the set rotation center line according to the set detection cycle.

[0007] Furthermore, the energy storage component does not discharge while charging, and does not charge while discharging.

[0008] According to another aspect of the present invention, a control circuit is provided for the above-described bearingless motor control method. The control circuit includes an energy storage component, a first line connected to the energy storage component, and a second line connected to the energy storage component. When the first line is connected to the energy storage component, the energy storage component is charged. The second line includes a damping coil. When the second line is connected to the energy storage component, the energy storage component is discharged to supply power to the damping coil.

[0009] Furthermore, the energy storage component includes an inductor. When the rotor of the bearingless motor rotates, the inductor generates an induced current to charge it under the influence of the magnetic field of the stator of the bearingless motor. The inductor is used to store electrical energy.

[0010] Furthermore, the energy storage component also includes a first capacitor for storing electrical energy.

[0011] Furthermore, the control circuit also includes a first switch and a second switch. The first switch controls the on / off state of the first line, and the second switch controls the on / off state of the second line. The second switch is closed when the first switch is open, and the second switch is open when the first switch is closed.

[0012] Furthermore, the second circuit also includes a second capacitor for storing electrical energy.

[0013] According to another aspect of the present invention, a bearingless motor is provided, which employs the above-described control circuit. The bearingless motor includes a stator, a rotor, and a control circuit, which includes an energy storage component and a damping coil.

[0014] Furthermore, the control circuit is located inside the rotor.

[0015] Furthermore, the control circuit also includes a first line connected to the energy storage component and a second line connected to the energy storage component. The second line includes a damping coil. The rotor includes a rotor shaft, a rotor core, and rotor baffles. The rotor shaft passes through the rotor core. The damping coil is disposed between the rotor shaft and the rotor core. The rotor baffles are disposed at the ends of the rotor core. The rotor baffles have grooves. The energy storage component and the first line are disposed in the grooves. The second line is partially disposed in the grooves.

[0016] This invention provides a bearingless motor control method. The bearingless motor includes a stator, a rotor, an energy storage component, and a damping coil. The control method includes: charging the energy storage component; detecting the offset of the rotor's actual rotation center line relative to a set rotation center line; if the rotor's offset is less than 20 μm, the energy storage component continues charging; if the rotor's offset is greater than or equal to 20 μm, the energy storage component discharges to power the damping coil. The damping coil generates a bias magnetic field, which, under the influence of the stator's magnetic field, causes the rotor to return to the set rotation center line. In this method, the energy storage component is first charged to store sufficient electrical energy. The rotor's position is detected to obtain the offset of the rotor's actual rotation center line relative to the set rotation center line. If the rotor's offset is less than 20 μm, the rotor's position has not shifted significantly and will not affect the operation of the bearingless motor. If the rotor offset is greater than 20μm, the energy storage component is controlled to discharge, which energizes the damping coil. The damping coil generates a bias magnetic field, which, under the action of the stator's magnetic field, generates a magnetic pull to send the rotor back to the set rotation center line, effectively solving the problem of rotor suspension and instability during the operation of the bearingless motor. Attached Figure Description

[0017] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A flowchart of a bearingless motor control method provided by an embodiment of the present invention is shown; Figure 2 It shows Figure 1 Control logic diagram of the bearingless motor control method in the text; Figure 3 A schematic diagram of the control circuit provided in an embodiment of the present invention is shown; Figure 4 A schematic diagram of the structure of a bearingless motor provided in an embodiment of the present invention is shown.

[0018] The above figures include the following reference numerals: 10. Energy storage component; 11. Inductor; 12. First capacitor; 21. Damping coil; 22. Second capacitor; 31. First switch; 32. Second switch; 40. Stator; 50. Rotor; 51. Rotor shaft; 52. Rotor core. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] like Figures 1 to 4 As shown, an embodiment of the present invention provides a bearingless motor control method. The bearingless motor includes a stator 40, a rotor 50, an energy storage assembly 10, and a damping coil 21. The bearingless motor control method includes: S10: Charge the energy storage component 10; S20: Detect the offset value of the actual rotation center line of rotor 50 relative to the set rotation center line; S30: If the offset of rotor 50 is less than 20μm, the energy storage component 10 continues to charge; if the offset of rotor 50 is greater than or equal to 20μm, the energy storage component 10 discharges to supply power to the damping coil 21. The damping coil 21 generates a bias magnetic field, which is subjected to the magnetic field of stator 40, causing rotor 50 to return to the set rotation center line.

[0021] This scheme first charges the energy storage component 10 to store sufficient electrical energy. The position of the rotor 50 is then detected to obtain the offset value of the actual rotation center line of the rotor 50 relative to the set rotation center line. If the offset value of the rotor 50 is less than 20μm, the position of the rotor 50 has not shifted significantly and will not affect the operation of the bearingless motor. If the offset value of the rotor 50 is greater than 20μm, the energy storage component 10 is controlled to discharge, energizing the damping coil 21. The damping coil 21 generates a bias magnetic field, which, under the action of the magnetic field of the stator 40, generates a magnetic pull to send the rotor 50 back to the set rotation center line, effectively solving the problem of rotor 50 levitation and instability during the operation of the bearingless motor.

[0022] like Figure 2 As shown, the energy storage component 10 is disposed inside the rotor 50. S10 further includes: the energy storage component 10 rotates with the rotor 50, and the energy storage component 10 generates an induced current under the action of the magnetic field of the stator 40 to charge the energy storage component 10.

[0023] With this configuration, the energy storage component 10 is placed inside the rotor 50, so that the energy storage component 10 rotates with the rotor 50. Under the action of the magnetic field of the stator 40, the energy storage component 10 generates an induced current to charge the energy storage component 10.

[0024] like Figure 2 As shown, the bearingless motor also includes a sensor, and S20 further includes: the sensor detects the offset value of the actual rotation center line of the rotor 50 relative to the set rotation center line according to the set detection cycle.

[0025] With this configuration, the bearingless motor also includes a sensor that detects the actual rotation centerline position of the rotor 50 to obtain the offset value of the actual rotation centerline of the rotor 50 relative to a set rotation centerline. The sensor detects the offset value in each set detection cycle. In a specific embodiment of the invention, the sensor employs a rotor position editor.

[0026] Furthermore, the energy storage component 10 does not discharge while charging, and does not charge while discharging. With this configuration, the charging and discharging of the energy storage component 10 cannot occur simultaneously.

[0027] like Figure 3 As shown, according to another aspect of the present invention, a control circuit is provided for the above-described bearingless motor control method. The control circuit includes an energy storage component 10, a first line connected to the energy storage component 10, and a second line connected to the energy storage component 10. When the first line is connected to the energy storage component 10, the energy storage component 10 is charged. The second line includes a damping coil 21. When the second line is connected to the energy storage component 10, the energy storage component 10 is discharged to supply power to the damping coil 21.

[0028] With this configuration, when the energy storage component 10 is connected to the first line, it forms... Figure 3 As shown in circle A, when circle A is in the closed state, the energy storage component 10 is charged. When the energy storage component 10 is connected to the second line, it forms... Figure 3 When circle B is closed, the energy storage component discharges to supply power to the damping coil 21. The damping coil 21 generates a bias magnetic field, and under the action of the magnetic field of the stator 40, the rotor 50 returns to the set rotation center line.

[0029] like Figure 3 As shown, the energy storage component 10 includes an inductor 11. When the rotor 50 of the bearingless motor rotates, the inductor 11 is charged by the magnetic field of the stator 40 of the bearingless motor, and the inductor 11 is used to store electrical energy.

[0030] With this configuration, the energy storage component 10 is located inside the rotor 50. When the rotor 50 rotates, the inductor 11 is induced by the magnetic field of the stator 40, which in turn charges the inductor 11, allowing the inductor 11 to store electrical energy for later use.

[0031] like Figure 3As shown, the energy storage component 10 also includes a first capacitor 12, which is used to store electrical energy. With this configuration, the first capacitor 12 is charged when circle A is connected and the inductor 11 generates an induced current for charging. When circle B is connected, the inductor 11 and the first capacitor 12 discharge to supply power to the damping coil 21.

[0032] like Figure 3 As shown, the control circuit also includes a first switch 31 and a second switch 32. The first switch 31 controls the on / off state of the first line, and the second switch 32 controls the on / off state of the second line. When the first switch 31 is open, the second switch 32 is closed, and when the first switch 31 is closed, the second switch 32 is open.

[0033] With this configuration, the first switch 31 controls the on / off state of the first circuit, and the second switch 32 controls the on / off state of the second circuit. The first switch 31 and the second switch 32 are opposite to each other and cannot be closed at the same time, so that the charging and discharging of the energy storage component 10 cannot be carried out simultaneously.

[0034] like Figure 3 As shown, the second circuit also includes a second capacitor 22, which is used to store electrical energy. With this configuration, when circle B is closed, the energy storage component 10 discharges to supply power to the damping coil 21, and at the same time charges the second capacitor 22. The second capacitor 22 increases the explosive force of the energy storage component 10 supplying power to the damping coil 21, so that the magnetic pull instantly sends the rotor 50 back to the set rotation center line.

[0035] According to another aspect of the present invention, a bearingless motor is provided, which employs the control circuit described above. The bearingless motor includes a stator 40, a rotor 50, and a control circuit, which includes an energy storage assembly 10 and a damping coil 21.

[0036] With this configuration, the bearingless motor uses the aforementioned control circuit, which makes the rotor 50 of the bearingless motor more stable in suspension, and sends the offset rotor 50 back to the set rotation center line, thus ensuring the stable operation of the bearingless motor.

[0037] Furthermore, the control circuit is located inside the rotor 50. With this configuration, the control circuit rotates as the rotor 50 rotates, thereby causing the inductor 11 to generate an induced current under the magnetic field of the stator 40, which charges the energy storage component 10.

[0038] like Figure 4As shown, the control circuit also includes a first line connected to the energy storage component 10 and a second line connected to the energy storage component 10. The second line includes a damping coil 21. The rotor 50 includes a rotor shaft 51, a rotor core 52 and rotor baffles. The rotor shaft 51 passes through the rotor core 52. The damping coil 21 is disposed between the rotor shaft 51 and the rotor core 52. The rotor baffles are disposed at the end of the rotor core 52. The rotor baffles have grooves. The energy storage component 10 and the first line are disposed in the grooves. The second line is partially disposed in the grooves.

[0039] In this configuration, the damping coil 21 is positioned between the rotor shaft 51 and the rotor core 52, allowing it to rotate with the rotor 50. When the energy storage assembly 10 supplies power to the damping coil 21, it generates a bias magnetic field, which, under the influence of the stator 40's magnetic field, returns to the set rotation center line. Rotor baffles are positioned at the ends of the rotor core 52 to protect it. The rotor baffles have grooves, within which the energy storage assembly 10 and the first circuit are located. The second circuit, except for the damping coil 21, is also located within the grooves. This allows the energy storage assembly 10 to rotate with the rotor 50, thereby generating an induced current for charging, and results in a compact structure.

[0040] like Figure 2 , 3 As shown, in the control logic, after the unit starts up, the levitation accuracy of rotor 50 will be automatically detected in each detection cycle. If the actual rotation center line of rotor 50 is offset from the set rotation center line by less than 20μm, the control circuit does not need to operate, and the charging and discharging circuit is in the default Circle A circuit, i.e., the charging state. If the detected offset of rotor 50 is greater than 20μm, the charging and discharging circuit will release electrical energy to generate a bias current. When the bias current passes through the damping coil 21 on rotor 50, it will generate a bias magnetic field, causing the rotor to return to the set rotation center line, effectively reducing mechanical vibration and the influence of external factors, and greatly improving the levitation stability of rotor 50.

[0041] In one specific embodiment of the present invention, the circuit topology includes two diodes, two capacitors, and two inductors (one of which is a damping coil 21 on the rotor). In the charge-discharge circuit, the first capacitor 12 is connected in parallel with the Circle A circuit and the Circle B circuit, and all components are placed in the grooves of the rotor baffle.

[0042] Circle A circuit: Inductor 11 and the first switch 31 are connected in series.

[0043] Circle B circuit: The damping coil 21 is connected in series with the second switch 32 and the second capacitor 22. The order of the first switch 31 and the second switch 32 must be controlled in the entire dual-loop charge-discharge circuit operation logic. It is stipulated that when one switch is active, the other is off.

[0044] When the rotor suspension accuracy is good (less than 20μm), the circuit will operate in circleA mode. At this time, the harmonic magnetic field in the motor air gap will charge the first capacitor 12 by step-down charging, that is, the second switch 32 will remain off, and the first switch 31 will be controlled by PWM. When the first switch 31 is connected, the power supply charges the inductor 11, the inductor 11 begins to store energy, and the inductor voltage Ui=UL; When the rotor levitation accuracy is poor (greater than 20μm), the circuit will operate in circleB mode. That is, the first switch 31 is open, and the first capacitor 12 and inductor 11 supply power to the damping coil 21 in the rotor 50, while also charging the second capacitor 22. At this time, according to KVL's law, Uo = Ui + UL, and the current of inductor 11 decreases linearly as it releases electrical energy. Due to the circuit discharge, the damping coil 21 generates a bias magnetic field, causing the rotor to return to the set rotation center line. The magnitude of the output voltage Uo is determined by the PWM duty cycle of the second switch 32.

[0045] Considering the switching losses, heat dissipation, noise reduction, and the typical switching frequency allowed by IGBTs, we take f = 2KHz-5KHz here.

[0046] The control circuit reduces rotor vibration when the motor is running under high voltage and heavy load, improves rotor stability and suspension accuracy, and effectively enhances resistance to external interference.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0048] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0049] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0050] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0051] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0052] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

Claims

1. A bearingless motor control method, characterized in that, The bearingless motor includes a stator (40), a rotor (50), an energy storage assembly (10), and a damping coil (21). The control method for the bearingless motor includes: S10: Charge the energy storage component (10); S20: Detect the offset value of the actual rotation center line of the rotor (50) relative to the set rotation center line; S30: If the offset value of the rotor (50) is less than 20μm, the energy storage component (10) continues to charge; if the offset value of the rotor (50) is greater than or equal to 20μm, the energy storage component (10) discharges to supply power to the damping coil (21), the damping coil (21) generates a bias magnetic field, and the bias magnetic field is subjected to the magnetic field of the stator (40) to make the rotor (50) return to the set rotation center line.

2. The bearingless motor control method according to claim 1, characterized in that, The energy storage assembly (10) is disposed within the rotor (50), and S10 further includes: The energy storage component (10) rotates with the rotor (50), and the energy storage component (10) generates an induced current under the magnetic field of the stator (40) to charge the energy storage component (10).

3. The bearingless motor control method according to claim 1, characterized in that, The bearingless motor also includes a sensor, and S20 further includes: The sensor detects the offset value of the actual rotation center line of the rotor (50) relative to the set rotation center line according to the set detection cycle.

4. The bearingless motor control method according to claim 1, characterized in that, The energy storage component (10) does not discharge when charging, and does not charge when discharging.

5. A control circuit, characterized in that, The control circuit is used in the bearingless motor control method according to any one of claims 1 to 4. The control circuit includes an energy storage component (10), a first line connected to the energy storage component (10), and a second line connected to the energy storage component (10). When the first line is connected to the energy storage component (10), the energy storage component (10) is charged. The second line includes a damping coil (21). When the second line is connected to the energy storage component (10), the energy storage component (10) is discharged to supply power to the damping coil (21).

6. The control circuit according to claim 5, characterized in that, The energy storage component (10) includes an inductor (11). When the rotor (50) of the bearingless motor rotates, the inductor (11) is charged by the magnetic field of the stator (40) of the bearingless motor. The inductor (11) is used to store electrical energy.

7. The control circuit according to claim 6, characterized in that, The energy storage component (10) also includes a first capacitor (12) for storing electrical energy.

8. The control circuit according to claim 5, characterized in that, The control circuit further includes a first switch (31) and a second switch (32). The first switch (31) controls the opening and closing of the first line, and the second switch (32) controls the opening and closing of the second line. When the first switch (31) is open, the second switch (32) is closed, and when the first switch (31) is closed, the second switch (32) is open.

9. The control circuit according to claim 5, characterized in that, The second line also includes a second capacitor (22) for storing electrical energy.

10. A bearingless motor, characterized in that, The bearingless motor employs the control circuit described in any one of claims 5 to 9. The bearingless motor includes a stator (40), a rotor (50), and a control circuit. The control circuit includes an energy storage component (10) and a damping coil (21).

11. The bearingless motor according to claim 10, characterized in that, The control circuit is located inside the rotor (50).

12. The bearingless motor according to claim 11, characterized in that, The control circuit also includes a first line connected to the energy storage component (10) and a second line connected to the energy storage component (10), the second line including the damping coil (21); the rotor (50) includes a rotor shaft (51), a rotor core (52) and a rotor baffle, the rotor shaft (51) passes through the rotor core (52), the damping coil (21) is disposed between the rotor shaft (51) and the rotor core (52), the rotor baffle is disposed at the end of the rotor core (52), the rotor baffle has a groove, the energy storage component (10) and the first line are disposed in the groove, and the second line is partially disposed in the groove.

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