Low power radial magnetic levitation stator structure

Abstract

This invention relates to a low-power radial magnetic levitation stator structure, comprising: multiple control windings and multiple bias windings wound according to the tooth cross-sectional dimensions of the stator core, nested on each tooth of the stator core, and with multiple slot wedges used for insertion and positioning of the control windings and bias windings; symmetrical control windings connected in series, with adjacent series-connected control windings connected in parallel; all bias windings connected in series sequentially; a controller connected to each set of series-connected control windings for x-axis and y-axis freedom direction control; each set of control windings connected to a displacement sensor, which feeds back a reference signal to the controller, generating a control magnetic field through the controller's output current. This low-power radial magnetic levitation stator structure uses only three power amplifiers, resulting in low overall power loss and simple control.

Description

Technical Field

[0001] This invention relates to magnetic levitation technology, and in particular to a low-power radial magnetic levitation stator structure. Background Technology

[0002] Magnetic levitation bearings have advantages such as non-contact operation, long lifespan, and high speed, and have attracted much attention in high-speed and ultra-high-speed fields. Currently, they are more mature in fields such as blowers, compressors, and vacuum pumps.

[0003] The radial magnetic levitation bearing body structure consists of a control coil, a stator core, a rotor core, and related insulation structures. The control part for the radial magnetic levitation bearing mainly includes sensors, a controller, and a power amplifier.

[0004] Figure 1 The diagram shown is a control block diagram of an existing radial magnetic levitation bearing. Figure 1 As shown, the existing radial magnetic levitation bearing structure requires two power amplifiers on each of the x and y axes for a single radial magnetic levitation bearing. Therefore, for the entire system, a total of eight power amplifiers are needed for the four degrees of freedom radial bearing, resulting in a large overall power loss. In addition, more circuits will also lead to the complexity of the process, lower fault tolerance, and relatively complex control. Summary of the Invention

[0005] The purpose of this invention is to provide a low-power radial magnetic levitation stator structure to solve the problem of multiple power amplifiers and large overall power loss in the prior art.

[0006] This invention discloses a low-power radial magnetic levitation stator structure, comprising: a radial magnetic levitation bearing structure including: a stator core, multiple control windings, multiple bias windings, and multiple slot wedges; the multiple control windings and multiple bias windings are wound according to the tooth cross-sectional dimensions of the stator core, and then nested on each tooth of the stator core, with the multiple slot wedges respectively providing insertion and limiting settings for the multiple control windings and multiple bias windings; the control windings with symmetrical teeth are connected in series, and adjacent series-connected control windings are connected in parallel in pairs; all bias windings are connected in series sequentially; a controller is distributed... Each set of series-connected control windings is used to control the x-axis and y-axis degrees of freedom. Each set of control windings is connected to a displacement sensor, and each set of control windings feeds back a reference signal through the displacement sensor. The controller outputs the current and generates a control magnetic field. The controller provides a bias circuit by connecting a bias winding to a first power amplifier, provides a control current for the y-axis direction by connecting a set of series-connected control windings to a second power amplifier, and provides a control current for the x-axis direction by connecting another set of series-connected control windings to a third power amplifier.

[0007] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, the plurality of control windings include two sets of control windings connected in series, and the controller is connected to the two sets of control windings in series respectively to perform directional control of the x-axis and y-axis; the two sets of control windings are respectively connected to a displacement sensor.

[0008] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, there are eight control windings, which are sequentially divided into first to eighth control windings; the eighth control winding is connected in series with the fourth control winding, the first control winding is connected in series with the fifth control winding, and the series structure of the first control winding and the fourth control winding is connected in parallel with the series structure of the first control winding and the fifth control winding; the second control winding is connected in series with the sixth control winding, the third control winding is connected in series with the seventh control winding, and the series structure of the second control winding and the sixth control winding is connected in parallel with the series structure of the third control winding and the seventh control winding; the series structure of multiple bias windings is placed at the root of the stator teeth.

[0009] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, the ampere-turns are determined according to the material of the stator core, and the stator core operates in the unsaturated region and the straight region of the stator core under the action of the bias current of the bias winding.

[0010] According to an embodiment of the low-power radial magnetic levitation stator structure of the present invention, each tooth corresponds to a control winding. After the bias winding is energized, NNSSNNSS is generated sequentially according to the order of the control winding, so that the magnetic poles generated by every two adjacent teeth generate a loop, and a total of four loops are generated, thereby generating a control magnetic field with one degree of freedom. Under the combined action of the two opposing magnetic poles, the rotor shaft is constrained by force on the x-axis and y-axis; the bias winding is energized by a constant current.

[0011] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, if the magnetic poles of the control winding need to enhance the magnetic poles generated by the bias current, the magnetic poles generated by the control current direction of the controller are in the same direction as the bias current magnetic poles; if the magnetic poles of the control winding need to weaken the magnetic poles generated by the bias current, the magnetic poles generated by the control current direction of the controller are in the opposite direction to the bias current magnetic poles.

[0012] According to an embodiment of the low-power radial magnetic levitation stator structure of the present invention, the structure of each set of series-parallel control windings is as follows: four control windings controlling the y-direction, each tooth's control winding is connected in series with the control winding of the tooth at a 180° relative position to form two windings, and the two windings are then connected in parallel.

[0013] According to an embodiment of the low-power radial magnetic levitation stator structure of the present invention, the probe of the displacement sensor detects the offset displacement signal, the displacement signal is processed by the comparator and the controller, the electrical signal is converted into a digital signal, and the digital signal is converted back into an electrical signal by the power amplifier, thereby changing the magnitude and direction of the current in the control winding to enhance or weaken the magnetic pole of each tooth, performing differential control, so that the rotor returns to the origin position.

[0014] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, the controller provides a bias current I+ by connecting to the eighth bias winding via a first power amplifier, and a bias current I- is drawn from the seventh bias winding. The controller provides a y-axis control current Iy+ by connecting to the first and eighth control windings via a second power amplifier, and a y-axis control current Iy- by connecting to the fifth and fourth control windings via the second power amplifier. The controller provides an x-axis control current Ix+ by connecting to the second and third control windings via a third power amplifier, and a x-axis control current Ix- by connecting to the sixth and seventh control windings via the third power amplifier.

[0015] According to one embodiment of the low-power radial magnetic levitation stator structure of the present invention, the bias winding and the control winding use wire gauges of the same size, and the number of turns of the bias winding is greater than that of the control winding.

[0016] The low-power radial magnetic levitation stator structure of the present invention can improve system reliability, simplify the process, use only three power amplifiers, have low overall power loss, and be easy to control. Attached Figure Description

[0017] Figure 1 The diagram shown is a control block diagram of an existing radial magnetic levitation bearing.

[0018] Figure 2 The diagram shown is of a radial magnetic levitation bearing structure.

[0019] Figure 3 for Figure 2 AA-direction cross-section diagram;

[0020] Figure 4 This is a partial enlarged view of the bias winding and control winding of a single slot in a radial magnetic levitation bearing.

[0021] Figure 5 This is a schematic diagram of the operating point of a silicon steel sheet under bias current.

[0022] Figure 6 The diagram shown is a schematic of the magnetic poles;

[0023] Figure 7 This is a schematic diagram of the bias winding connection.

[0024] Figure 8 The diagram shown is the wiring diagram of the first control winding;

[0025] Figure 9 The diagram shown is the wiring diagram of the second control winding;

[0026] Figure 10 The diagram shows the control system block diagram of the radial magnetic levitation bearing. Detailed Implementation

[0027] To make the objectives, contents, and advantages of the present invention clearer, the specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.

[0028] Figure 2 The diagram shown is of a radial magnetic levitation bearing. Figure 3 for Figure 2 AA-direction cross-section diagram, Figure 4 This is a partial enlarged view of the bias winding and control winding of a single slot in a radial magnetic levitation bearing, as shown below. Figures 2 to 4 As shown, the radial magnetic levitation bearing of the present invention mainly includes a radial magnetic levitation bearing stator core 1, a control winding 3, an offset winding 2, and a slot wedge 4. The control winding 3 and the offset winding 2 are wound according to the cross-sectional dimensions of the teeth of the stator core 1 and then nested on each tooth of the stator core 1. The slot wedge 4 is used to limit the insertion of the control winding 3 and the offset winding 2, preventing them from falling off.

[0029] Figure 5 This is a schematic diagram of the operating point of a silicon steel sheet under bias current, as shown below. Figures 2 to 5 As shown, every four control windings 3 are connected in series, including: the eighth control winding and the fourth control winding connected in series, the first control winding and the fifth control winding connected in series, and the eighth and fourth control windings connected in parallel with the first and fifth control windings. The second control winding and the sixth control winding are connected in series, the third control winding and the seventh control winding are connected in series, and the second and sixth control windings are connected in parallel with the third and seventh control windings. Multiple bias windings are connected in series sequentially and placed at the root of the stator teeth. A suitable ampere-turns number is calculated based on the core material, so that the core operates in the unsaturated region and the straight region of the core under the action of bias current.

[0030] Figure 6 The diagram shown is a schematic of the magnetic poles. Figure 7 This is a schematic diagram of the bias winding connection, as shown below. Figure 6 as well as Figure 7As shown, each tooth is numbered clockwise from 1 to 8. When the bias winding is energized, the stator core poles generate NNSSNNSS sequentially from 1 to 8, creating a loop between every two adjacent teeth, for a total of four loops. This generates a control magnetic field for one degree of freedom, which, together with the opposing poles, constrains the rotor shaft along the x and y axes. For example, in the x-direction, the first and eighth poles are opposite in direction, constraining the shaft along the x-axis with the opposing fourth and fifth poles. In the y-axis direction, the second, third, sixth, and seventh poles constrain the shaft. The bias winding 2 is energized with a constant current and connected in series; therefore, the electromagnetic force generated by the bias winding is a constant value. Figure 6 As shown by the dashed line, this ensures good consistency of the system's static operating point and facilitates adjustment.

[0031] Figure 8 The diagram shown is the wiring diagram of the first control winding. Figure 9 The diagram shown is the wiring diagram of the second control winding. Figure 8 as well as Figure 9 As shown, the control winding is controlled by a controller with variable current. The four coils of the control winding, representing the X and Y degrees of freedom, are connected in series and parallel to control the resulting control magnetic field, which may be strengthened or weakened. For example... Figure 6 If the rotor shown is eccentric along the negative y-direction, the magnetic poles generated by the control winding current will be as follows: Figure 7 as well as Figure 8 As shown, the first and eighth magnetic poles require enhanced magnetic poles generated by the bias current, so the magnetic poles generated by the control current direction are in the same direction as the bias current magnetic poles. The fourth and fifth magnetic poles require weakened magnetic poles generated by the bias current, so the magnetic poles generated by the control current direction are in opposite directions to the bias current magnetic poles. The eccentricity of the rotor in each of the four quadrants is decomposed into x and y directions. By controlling the magnitude and direction of the control current to enhance or weaken the magnetic poles of the bias current, differential control is achieved, allowing the rotor to return to its original position.

[0032] The control windings are connected in series and parallel as follows: For the four windings controlling the y-direction, each tooth's control winding is connected in series with the control winding of the tooth at a 180° relative position, forming two windings. These two windings are then connected in parallel. For example, the first and fifth windings are opposite magnetic poles, and their control windings are connected in series. The fourth and eighth control windings are connected in series and then in parallel. The resulting control magnetic field either strengthens or weakens the magnetic field generated by the original bias current. The principle for controlling the x-direction is similar to that for controlling the y-direction.

[0033] Figure 10 The diagram shown is a control system block diagram of a radial magnetic levitation bearing. Figure 10As shown, the controller connects two sets of series-connected control windings to control the x-axis and y-axis directions of the control windings. Each set of control windings is connected to a displacement sensor. Control winding 3 generates a control magnetic field based on feedback from the displacement sensor according to the disturbance received by the system. When there is no disturbance signal or self-excited vibration, its control current is zero, facilitating adjustment of control parameters and significantly reducing power consumption. The displacement sensor probe detects the offset displacement signal, which is processed by a comparator and the controller. The electrical signal is converted into a digital signal, and then converted back into an electrical signal by a power amplifier. This alters the magnitude and direction of the current in the control winding, thereby strengthening or weakening the magnetic pole of each tooth, performing differential control, and allowing the rotor to return to its original position.

[0034] like Figure 10 As shown, assuming the rotor is offset by e along the third quadrant, then the offset components in x and y are e. x e y The displacement sensor in the y-direction detected a displacement of e. y It generates a displacement-related voltage signal, compares it with the reference input electrical signal (assumed to be 0A), performs digital signal processing on the electrical signal by the controller, outputs it to the power amplifier for amplification, and converts it into an electrical signal to control the magnitude and direction of the control coil current. That is, the first, eighth, fourth, and fifth bias windings control the offset in the y-direction, and their corresponding magnetic poles are N, S, S, and N, respectively. For the rotor to return to its original position, a force in the positive y-direction is required. Applying a positive current can increase the magnetic field strength of the first and eighth magnetic poles and weaken the magnetic field strength of the fourth and fifth magnetic poles. As a result, the magnetic force in the positive y-direction is greater than the magnetic force in the negative y-direction, generating an upward force on the rotor. The control method in the x-direction is the same.

[0035] like Figures 7 to 10 As shown in this embodiment, Figure 7 As shown, the controller provides a bias current I+ by connecting to the eighth bias winding via a first power amplifier, and a bias current I- is drawn from the seventh bias winding. The controller provides a y-axis control current Iy+ by connecting to the first and eighth control windings via a second power amplifier, and a y-axis control current Iy- by connecting to the fifth and fourth control windings via the second power amplifier. The controller provides an x-axis control current Ix+ by connecting to the second and third control windings via a third power amplifier, and a x-axis control current Ix- by connecting to the sixth and seventh control windings via the third power amplifier.

[0036] The bias current requires one power amplifier, and the control windings for the y-axis and x-axis each require one power amplifier. Therefore, a single radial magnetic levitation bearing uses a total of three power amplifiers. The bias winding 2 and the control winding 3 use wire gauges of the same size, but the number of turns in the bias winding 2 is greater than that in the control winding 3, to ensure that the magnetic pole of each tooth generated under the maximum current of the control winding 3 remains unchanged.

[0037] The advantages of this invention are: (1) In terms of system structure, the architecture is simplified, the process is simple, and the cost is reduced; (2) In terms of performance, power consumption is reduced and system efficiency is improved; (3) In terms of reliability, the system reliability is improved and the system fault tolerance is increased; (4) In terms of control, the architecture is simplified, the control is relatively simple, the consistency of the main structure is good, and the control parameters are easy to adjust.

[0038] 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 technical principles 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 low-power radial magnetic levitation stator structure, characterized in that, include: The radial magnetic levitation bearing structure includes: a stator core, multiple control windings, multiple bias windings, and multiple slot wedges; Multiple control windings and multiple bias windings are wound according to the tooth cross-sectional dimensions of the stator core, and then nested on each tooth of the stator core. Multiple slot wedges are used to set the insertion limit of the multiple control windings and multiple bias windings respectively. The control windings with symmetrical teeth are connected in series, and the two adjacent series-connected control windings are connected in parallel in pairs. All bias windings are connected in series in sequence. A controller is connected to each set of series-connected control windings to control the x-axis and y-axis degrees of freedom. Each set of control windings is connected to a displacement sensor, and each set of control windings feeds back a reference signal through the displacement sensor, thereby generating a control magnetic field through the controller's output current. The controller provides bias circuitry by connecting a bias winding to a first power amplifier, provides control current for the y-axis direction by connecting a set of series control windings to a second power amplifier, and provides control current for the x-axis direction by connecting another set of series control windings to a third power amplifier.

2. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, The multiple control windings include two sets of control windings connected in series. The controller is connected to the two sets of control windings in series respectively to perform directional control of the x-axis and y-axis; each set of control windings is connected to a displacement sensor.

3. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, There are 8 control windings, which are divided into the first to the eighth control windings in sequence; The eighth control winding is connected in series with the fourth control winding, the first control winding is connected in series with the fifth control winding, and the series structure of the first control winding and the fourth control winding and the series structure of the first control winding and the fifth control winding are connected in parallel. The second control winding is connected in series with the sixth control winding, the third control winding is connected in series with the seventh control winding, and the series structure of the second control winding and the sixth control winding and the series structure of the third control winding and the seventh control winding are connected in parallel. The series structure of multiple bias windings is placed at the root of the stator teeth.

4. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, The ampere-turns are determined based on the material of the stator core, and the stator core is made to operate in the unsaturated region and the straight region of the stator core under the action of the bias current of the bias winding.

5. The low-power radial magnetic levitation stator structure as described in claim 3, characterized in that, Each tooth corresponds to a control winding. After the bias winding is energized, NNSSNNSS is generated in sequence according to the order of the control winding, so that the magnetic poles generated by every two adjacent teeth form a loop, and a total of four loops are generated, thereby generating a control magnetic field with one degree of freedom. Under the combined action of the two opposite magnetic poles, the rotor shaft is constrained by force on the x-axis and y-axis. The bias winding is energized with a constant current.

6. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, If the magnetic poles of the control winding need to be strengthened by the bias current, the magnetic poles generated by the controller's control current direction are in the same direction as the bias current magnetic poles. If the magnetic poles of the control winding need to be weakened by the bias current, the magnetic poles generated by the controller's control current direction are in the opposite direction to the bias current magnetic poles.

7. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, The structure of each set of series-parallel control windings is as follows: four control windings control the y-direction, and the control winding of each tooth is connected in series with the control winding of the tooth at a 180° relative position to form two windings, which are then connected in parallel.

8. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, The displacement sensor probe detects the offset displacement signal. After the comparator and controller process the displacement signal, the electrical signal is converted into a digital signal. Then, after the power amplifier converts the digital signal back into an electrical signal, the magnitude and direction of the current in the control winding are changed, thereby strengthening or weakening the magnetic pole of each tooth, performing differential control, and making the rotor return to the origin position.

9. The low-power radial magnetic levitation stator structure as described in claim 3, characterized in that, The controller provides a bias current I+ to the eighth bias winding via a first power amplifier, and a bias current I- is drawn from the seventh bias winding. The controller provides a y-axis control current Iy+ to the first and eighth control windings via a second power amplifier, and a y-axis control current Iy- to the fifth and fourth control windings via the same second power amplifier. The controller provides an x-axis control current Ix+ to the second and third control windings via a third power amplifier, and a x-axis control current Ix- to the sixth and seventh control windings via the same third power amplifier.

10. The low-power radial magnetic levitation stator structure as described in claim 1, characterized in that, The bias winding and the control winding use wire gauges of the same size, with the bias winding having more turns than the control winding.

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