CN116154988A - Natural electromagnetic magnetic suspension three-phase permanent magnet motor - Google Patents
Natural electromagnetic magnetic suspension three-phase permanent magnet motor Download PDFInfo
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- CN116154988A CN116154988A CN202310255520.6A CN202310255520A CN116154988A CN 116154988 A CN116154988 A CN 116154988A CN 202310255520 A CN202310255520 A CN 202310255520A CN 116154988 A CN116154988 A CN 116154988A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/12—Stationary parts of the magnetic circuit
- H02K1/14—Stator cores with salient poles
- H02K1/146—Stator cores with salient poles consisting of a generally annular yoke with salient poles
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K1/00—Details of the magnetic circuit
- H02K1/06—Details of the magnetic circuit characterised by the shape, form or construction
- H02K1/22—Rotating parts of the magnetic circuit
- H02K1/27—Rotor cores with permanent magnets
- H02K1/2706—Inner rotors
- H02K1/272—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis
- H02K1/274—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets
- H02K1/2753—Inner rotors the magnetisation axis of the magnets being perpendicular to the rotor axis the rotor consisting of two or more circumferentially positioned magnets the rotor consisting of magnets or groups of magnets arranged with alternating polarity
- H02K1/278—Surface mounted magnets; Inset magnets
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K3/00—Details of windings
- H02K3/04—Windings characterised by the conductor shape, form or construction, e.g. with bar conductors
- H02K3/28—Layout of windings or of connections between windings
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
- H02N15/00—Holding or levitation devices using magnetic attraction or repulsion, not otherwise provided for
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
- H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/60—Other road transportation technologies with climate change mitigation effect
- Y02T10/64—Electric machine technologies in electromobility
Abstract
A natural electromagnetic magnetic suspension three-phase permanent magnet motor relates to the field of motors. The invention aims to solve the problems that a magnetic suspension bearing in a magnetic suspension motor is large in size and difficult to control. According to the natural electromagnetic magnetic suspension three-phase permanent magnet motor, a stator core and a surface-mounted permanent magnet are divided into n sections along the axial direction, wherein n is a positive integer greater than or equal to 3; when the ratio of the stator slot number Z on the stator core to the phase number m of the stator winding is an odd number, the common divisor exists between the motor pole number P and Zm; each phase of stator winding comprises K pairs of branches connected in parallel, K is more than or equal to 1 and less than or equal to Z2m, the two branches connected in parallel are arranged in central symmetry by taking the center of a motor as a symmetry center, when the pole pair number P of the motor is even, the different name ends of the two branches are connected, and when the pole pair number P of the motor is even, the same name ends of the two branches are connected.
Description
Technical Field
The invention belongs to the field of motors, and particularly relates to a motor winding.
Background
Motors are the most common and most commonly used electrical devices. Such as energy storage flywheels, maglev trains, all-electric aircraft turbine engines, marine hydraulic propulsion, ultra-low noise submarine drives, ocean tide power generation, nuclear power, space and ultra-high speed applications, and the like. The conventional motors all have bearings, and friction is desirably as small as possible, and magnetic levitation is a necessary technique. In general, in a magnetic suspension motor, the volume of a magnetic suspension bearing accounts for 60%, and the cost of a controller of the magnetic suspension bearing is high and complex, so that the suspension of a motor rotor is a difficult problem.
Disclosure of Invention
The invention provides a natural electromagnetic magnetic suspension three-phase permanent magnet motor, which aims to solve the problems that a magnetic suspension bearing in a magnetic suspension motor is large in size and difficult to control.
A natural electromagnetic maglev three-phase permanent magnet motor comprising: the rotor comprises a rotor core and a stator winding, wherein the rotor comprises a rotor core and a surface-mounted permanent magnet, the stator core and the surface-mounted permanent magnet are axially divided into n sections, and n is a positive integer greater than or equal to 3; when the ratio of the stator slot number Z on the stator core to the phase number m of the stator winding is an odd number, the common divisor exists between the motor pole number P and Zm; each phase of stator winding comprises K pairs of branches connected in parallel, K is more than or equal to 1 and less than or equal to Z2m, the two branches connected in parallel are arranged in central symmetry by taking the center of a motor as a symmetry center, when the pole pair number P of the motor is even, the different name ends of the two branches are connected, and when the pole pair number P of the motor is even, the same name ends of the two branches are connected.
Further, a stator gap lambda between the two axially adjacent stator cores d Rotor gap lambda between two axially adjacent surface-mounted permanent magnets r Equal and have lambda d ＝λ r =δ -2 δ, δ being the electromagnetic air gap.
Alternatively, the stator gap λ between the two axially adjacent stator cores d Gap lambda between adjacent two sections of non-end surface-mounted permanent magnets r0 Equal and have lambda d ＝λ r0 =δ -2δ, δ being the electromagnetic air gap; gap lambda between a permanent magnet segment at the end and its adjacent permanent magnet segment rd ＞λ r0 And has lambda rd ＝1.5λ r0 ～2λ r0 。
Furthermore, the natural electromagnetic magnetic suspension three-phase permanent magnet motor further comprises a shell, and the rotor and the stator are both positioned inside the shell.
Further, one end of the two branches is taken as the midpoint of the phase winding.
Furthermore, the same-name ends of windings in two adjacent slots in each phase of stator winding are connected in series to form a branch.
The invention only needs to adopt proper pole slot matching, and can realize radial natural dynamic electromagnetic magnetic suspension and axial passive magnetic suspension by combining the motor windings in series and parallel and matching with iron core segments on the premise of not adding any sensor or controller. The invention can realize the self-weight unloading of any motor with a bearing, prolongs the service life of the bearing, reduces the noise, reduces the motor loss and saves energy. Natural electromagnetic magnetic levitation can enable a motor rotor to rotate in a state that energy loss tends to be minimum, and vibration and noise are minimum at the moment. The device is particularly suitable for wind power generators, turbine engines or hydroelectric generators, compressor motors, dust collector motors, high-speed crushers and the like.
Drawings
FIG. 1 is a schematic diagram of a conventional 14-pole 12-slot motor, wherein each phase has a branch;
FIG. 2 is an axial schematic cross-section of a natural electromagnetic maglev three-phase permanent magnet motor according to the present invention;
FIG. 3 is a schematic diagram of a 10-pole 12-slot natural magnetic levitation motor having a pair of parallel branches for each phase;
FIG. 4 is a schematic diagram of a 14 pole 12 slot natural magnetic levitation motor having a pair of parallel legs for each phase;
FIG. 5 is a schematic diagram of a 10-pole 12-slot natural magnetic levitation motor having a pair of shorted windings for each phase;
FIG. 6 is a schematic diagram of a 10-pole 12-slot natural magnetic levitation motor having two pairs of parallel branches per phase;
fig. 7 is a schematic diagram of a 10-pole 12-slot natural magnetic levitation motor having a pair of parallel branches and a pair of shorted windings for each phase.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention. It should be noted that, without conflict, the embodiments of the present invention and features of the embodiments may be combined with each other.
In the conventional motor, when the ratio of the number of poles Z (tooth space number) to the number of phases m is an even number, there is usually only one branch per phase, as shown in fig. 1, and there are 1 branch per phase in the three-phase symmetric 14-pole 12-slot motor. If the motor air gap is eccentric, three-phase current asymmetry can be generated, and the motor eccentric vibration and noise are caused, so that the traditional motor can not generate magnetic suspension restoring force. For this purpose, the present invention provides the following embodiments.
The first embodiment is as follows: the embodiment of the natural electromagnetic magnetic suspension three-phase permanent magnet motor comprises: the rotor, the stator and the shell 7 are coaxially nested from inside to outside, the stator comprises a stator core 1 and a stator winding 5, and the rotor comprises a rotor core 2 and a surface-mounted permanent magnet 3.
The stator core 1 and the surface-mounted permanent magnet 3 are divided into n=5 sections along the axial direction. Stator gap 6λ between two axially adjacent stator cores 1 d Gap lambda between adjacent two sections of non-end surface-mounted permanent magnets 3 r0 Equal and have lambda d ＝λ r0 =δ -2 δ, δ being the electromagnetic air gap. Gap lambda between a permanent magnet segment at the end and its adjacent permanent magnet segment rd ＞λ r0 And has lambda rd ＝1.5λ r0 ～2λ r0 . The maximum rigidity of the segmented axial passive magnetic suspension is approximately as follows: 0.95nK (Nmmm), wherein K (Nmmm) is the stiffness of single-segment axial passive magnetic levitation.
The ratio of the number of stator slots Z on the stator core 1 to the number of phases m of the stator winding 5 is even, so that each phase winding of the motor can form a winding distributed in a central symmetry manner and a force couple moment in a central symmetry manner can be generated. And when Zm is odd, the motor with natural electromagnetic magnetic suspension is not beneficial. There is a common divisor of the motor pole numbers P and Zm when the ratio of the number of stator slots Z on the stator core 1 to the number of phases m of the stator winding 5 is an odd number. For example, p=3, zm=3, and the common divisor is 3; p=15, zm=9, common divisor 3; p=10, zm=5, and common divisor is 5.
Each phase of stator winding 5 comprises K pairs of branches which are mutually connected in parallel, wherein K is more than or equal to 1 and less than or equal to Z2m. The tail ends of adjacent windings in each phase are connected in series to form a branch, and then connected in series with the tail ends of adjacent windings symmetrically distributed at 180 degrees to form another branch, and then the two symmetrical branches are connected to form a parallel branch winding. One end of each branch is taken as the midpoint of the phase winding. And the two parallel branches are arranged in a central symmetry way by taking the center of the motor as the symmetry center. When the pole pair number P of the motor is even, the heteronymous ends of the two branches are connected in parallel; when the pole pair number P of the motor is even, the homonymous ends of the two branches are connected in parallel. The motor becomes a motor with natural electromagnetic magnetic suspension restoring force. The three-phase windings of the motor are respectively formed into 180-degree symmetrical parallel branches according to the method, so that three-phase ports of the three-phase windings and midpoints of one three-phase winding are generated. Namely, the special parallel branch three-phase windings which are symmetrically connected in parallel at 180 degrees are finally formed. The more parallel branches, the more turns per slot, and the greater the restoring force. The restoring force of natural electromagnetic magnetic suspension is proportional to the square of the increase multiple of the parallel branch.
Because the attractive force exists between the stator iron core 1 and the surface-mounted permanent magnet 3, the air gap between the stator and the rotor is kept equal under the action of the bearing, the attractive force is equal everywhere along the circumference, and the radial attractive force in the air gap of the motor is equal everywhere and counteracts each other by the bearing. However, if the motor rotates and the bearing fails, when the air gap between two sections with the same diameter of the motor is deviated, the permanent magnet rotor body is sucked to the side with the small air gap, the counter potential of the parallel branch on the side with the small air gap is increased, the current is decreased, the counter potential of the parallel branch on the side with the large air gap is decreased, the current is increased, the radial tension on the side with the large air gap is increased, the radial tension on the side with the small air gap is decreased, the air gap is inevitably changed in the direction of decreasing the deviation, and the deviation of the air gap is stabilized. Therefore, after the motor rotates, the embodiment has the capability of radial natural magnetic suspension recovery centering.
The permanent magnet is the main body of the motor for generating driving moment, but the permanent magnet also generates uncontrolled radial magnetic pulling force f jx . The force uncertainly pulls the motor in any direction where the air gap is zero. Therefore, magnetic suspension force f generated by radial natural electromagnetic active magnetic suspension je Must be greater than f jx Thereby ensuring the synthesized radial magnetic levitation force f j Can generate stable radial magnetic suspension effect.
Radial magnetic tension force f generated by permanent magnet jx ＝B δ A2μ 0 Mu in the middle 0 Air gap permeability, A is air gap surface area per pole, B δ Is air gap magnetic density. The larger the electromagnetic air gap is, the air gap flux density B δ The smaller the electromagnetic air gap becomes, the air gap flux density B δ Will become smaller. When the electromagnetic air gap is relatively small, the change relation is linear, and when the electromagnetic air gap is relatively large, the change relation is a power function. The magnetic levitation force generated by natural electromagnetic active magnetic levitation is in direct proportion to the square of the current deviation or the square of the counter potential deviation of the parallel branch circuit and in direct proportion to the square of the number of turns of the winding. The stable magnetic suspension conditions of radial natural electromagnetic magnetic suspension are as follows: f (f) je ＞f jx . Because the motor rotating speed is zero, the radial natural electromagnetic magnetic levitation force is zero, and the motor rotor can be attracted to any position with zero mechanical air gap. The present technology cannot provide static radial electromagnetic magnetic levitation. Typically the mechanical air gap delta of the motor j Less than the electromagnetic air gap, i.e. the change range of the air gap is only + -delta when the motor works j Radial magnetic tension f generated by the permanent magnet at this time jx Relatively small. The larger the motor diameter is, the smaller the radial magnetic pulling force is due to the relatively smaller air gap, so the larger the natural electromagnetic magnetic levitation force is, and the larger the motor is suitable for a large motor.
Since the permanent magnet rotor is randomly attracted to the side with the small air gap in the initial state when the motor is not started, the permanent magnet rotor body is unstable in the radial direction. Therefore, the protection bearing can be used in practical application. Under the condition of not adding any sensor and controller, the implementation mode adopts the traditional motor driving method to have perfect dynamic radial natural electromagnetic magnetic suspension and passive axial magnetic suspension functions.
As shown in fig. 5 and 7, in order to increase the natural magnetic levitation restoring force, a short-circuit winding dedicated to increasing the natural magnetic levitation restoring force may be further added to each adjacent empty slot. Based on the same principle, attractive force exists between the stator core 1 and the surface-mounted permanent magnet 3, the air gap between the stator and the rotor is kept equal due to the effect of the bearing, the attractive force is equal everywhere along the circumference, and the bearing enables the radial attractive force in the air gap of the motor to be equal everywhere and offset each other. However, if the motor rotates and the bearing fails, the air gaps at the two sides of 180 degrees are inevitably deviated, at the moment, the permanent magnet rotor body is sucked to the side with small air gap, and the counter potential deviation of the parallel short-circuit winding branch at the side with small air gap is inevitably increased, and the current is decreased; on the contrary, the counter potential of the short-circuit winding branch is reduced at the side with the large air gap, the current is increased, the radial pulling force at the side with the large air gap is increased, the radial pulling force at the side with the small air gap is reduced, the air gap is inevitably changed in the direction of reducing the deviation, and the deviation of the air gap is stabilized. The radial natural magnetic suspension recovery is proportional to the square of the counter-potential deviation, so the method for adding the special radial natural magnetic suspension winding can be adopted when needed.
For motors with output shafts, in order to increase the variation in load on their output shafts, auxiliary bearings are still added, which can be smaller in size than conventional bearings, in order to reduce bearing friction: the excircle of the auxiliary bearing can be sleeved with an elastic rubber ring so as to provide mechanical buffering and reduce vibration and noise of the motor; the bearing clearance of the auxiliary bearing can be increased to 0.1-1 mm from the negative clearance; the axial center of the motor output shaft is kept stable under the action of natural electromagnetic magnetic suspension restoring force. At this time, although the auxiliary bearing is arranged, the natural electromagnetic magnetic suspension can still enable the motor rotor to rotate in a state that the energy loss tends to be minimum, and at this time, the vibration and the noise are minimum, like the natural rotation of the earth and the sun in space.
Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims. It should be understood that the different dependent claims and the features described herein may be combined in ways other than as described in the original claims. It is also to be understood that features described in connection with separate embodiments may be used in other described embodiments.
Claims (6)
1. A natural electromagnetic maglev three-phase permanent magnet motor comprising: the rotor and the stator are coaxially nested from inside to outside, the stator comprises a stator iron core (1) and a stator winding (5), the rotor comprises a rotor iron core (2) and a surface-mounted permanent magnet (3),
the stator is characterized in that the stator core (1) and the surface-mounted permanent magnet (3) are divided into n sections along the axial direction, wherein n is a positive integer greater than or equal to 3;
when the ratio of the number Z of stator slots on the stator core (1) to the number m of phases of the stator winding (5) is an odd number, the number P of motor poles and Zm have a common divisor;
each phase of stator winding (5) comprises K pairs of branches connected in parallel, K is more than or equal to 1 and less than or equal to Z2m, the two branches connected in parallel are arranged in a central symmetry way by taking the center of a motor as a symmetry center, when the pole pair number P of the motor is even, the different name ends of the two branches are connected, and when the pole pair number P of the motor is even, the same name ends of the two branches are connected.
2. A natural electromagnetic maglev three-phase permanent magnet machine according to claim 1 characterized in that the stator gap (6) lambda between axially adjacent two stator cores (1) d Rotor gap (4) lambda between two axially adjacent surface-mounted permanent magnets (3) r Equal and have lambda d ＝λ r =δ -2 δ, δ being the electromagnetic air gap.
3. A natural electromagnetic maglev three-phase permanent magnet motor according to claim 1, characterized in that the stator gap (6) between axially adjacent two stator cores (1) has a length λ d Gap length lambda between two adjacent sections of non-end surface-mounted permanent magnets (3) r0 Equal and have lambda d ＝λ r0 =δ -2δ, δ being the electromagnetic air gap;
gap lambda between a permanent magnet segment at the end and its adjacent permanent magnet segment rd ＞λ r0 And has lambda rd ＝1.5λ r0 ～2λ r0 。
4. A natural electromagnetic levitation three-phase permanent-magnet machine according to claim 1, 2 or 3, further comprising a housing (7), said rotor and stator being both located inside the housing (7).
5. A natural electromagnetic levitation three-phase permanent-magnet machine according to claim 4 wherein one end of both branches is taken as the midpoint of the phase winding.
6. A natural electromagnetic maglev three-phase permanent-magnet machine according to claim 4, characterized in that the windings in adjacent two slots in each phase of stator winding (5) are connected in series with the same name end to form a branch.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310255520.6A CN116154988A (en) | 2023-03-16 | 2023-03-16 | Natural electromagnetic magnetic suspension three-phase permanent magnet motor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310255520.6A CN116154988A (en) | 2023-03-16 | 2023-03-16 | Natural electromagnetic magnetic suspension three-phase permanent magnet motor |
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| Publication Number | Publication Date |
|---|---|
| CN116154988A true CN116154988A (en) | 2023-05-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310255520.6A Pending CN116154988A (en) | 2023-03-16 | 2023-03-16 | Natural electromagnetic magnetic suspension three-phase permanent magnet motor |
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| Country | Link |
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| CN (1) | CN116154988A (en) |
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2023
- 2023-03-16 CN CN202310255520.6A patent/CN116154988A/en active Pending
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