CN116231996A

CN116231996A - Limit environment natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor

Info

Publication number: CN116231996A
Application number: CN202310255516.XA
Authority: CN
Inventors: 赵辉; 杨贵杰; 苏健勇; 李铁才
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2023-03-16
Filing date: 2023-03-16
Publication date: 2023-06-06

Abstract

A limit environment natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor belongs to the field of magnetic suspension three-phase permanent magnet motors. The problems that the cost for suspending the motor rotor is high, the volume ratio of the magnetic suspension bearing in the magnetic suspension motor is high, and the controller is complex are solved. The gap of the starting protection mechanical bearing at the end part of the rotor core is set to be 0.1mm to 0.5mm; the stator core is divided into three sections or more, and gaps exist between two adjacent sections; the stator winding is divided into a plurality of pairs of windings symmetrically distributed along the circumference by 180 degrees; the maximum winding pair number of each phase is Kpm =Z/(2 m), the tail ends of adjacent windings of each phase are connected in series to form one branch, the tail ends of adjacent windings which are symmetrically distributed at 180 degrees are connected in series to form the other branch, and two symmetrical branches are connected into 180-degree symmetrical parallel branches, so that three-phase ports of three-phase windings and midpoints of one three-phase winding are generated. The invention is mainly used in extreme environments.

Description

Limit environment natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor

Technical Field

The invention belongs to the field of magnetic suspension three-phase permanent magnet motors, and particularly relates to a suspension three-phase permanent magnet synchronous motor used in a limit environment.

Background

The extreme environment also requires motion control components. For example: spacecraft, which require high rotational speeds for operation at low temperatures, have too short a mechanical bearing life and therefore require a motor with levitation capability. The temperature difference between the moon surface and day and night is extremely large and can reach-180 ℃ to +150 ℃, and a detector working on the moon surface and a patrol detector are exposed to the limit environment, so that a servo driving assembly capable of directly operating in the limit environment is needed. For example: large mechanical equipment used in a space limitation environment, a satellite off-bin manipulator (robot), a power generation system and an energy storage system used in the space limitation environment, and the like. Similarly: the earth also has limited environments such as: nuclear radioactive environments, extreme temperature differential environments, sudden hazardous environments, and the like.

The key points of breaking through the limit temperature difference environment are as follows: the traditional bearing adopts a negative gap to improve the precision, and the expansion and contraction of the mechanical bearing inevitably causes the damage, the seizing or the abrasion of the bearing gap. Therefore, a bearingless design is chosen to solve this problem.

However, the cost of suspending the motor rotor is too high, in general, in a magnetic suspension motor, the volume of the magnetic suspension bearing accounts for 60%, and the cost of a controller of the magnetic suspension bearing is high and complex. Magnetic levitation motors are a costly luxury and are not accessible. Therefore, the above problems need to be solved.

Disclosure of Invention

The invention aims to solve the problems of high cost for suspending a motor rotor, high volume ratio of a magnetic suspension bearing in a magnetic suspension motor and complex controller, and provides a natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor in a limit environment.

The motor is a fractional slot concentrated winding motor, the ratio of the number of tooth slots to the number of phases of the motor is Z/m, Z/m is even, each phase winding of the motor forms windings symmetrically distributed along the circumference by 180 degrees, and force couple moments symmetrically distributed by 180 degrees are generated; the motor comprises a rotor and a stator sleeved outside the rotor, and the stator is fixed on the stator shell;

the rotor comprises a rotor core and rotor permanent magnets; the rotor permanent magnet is arranged on the rotor core, and the starting protection mechanical bearing clearance at the end part of the rotor core is set to be 0.1mm to 0.5mm;

the stator comprises a stator core and a stator winding; the stator winding is wound on the stator core, the stator core is axially divided into three sections or more, and gaps exist between two adjacent sections; the stator winding is a three-phase winding;

the stator winding is divided into a plurality of pairs of windings symmetrically distributed along the circumference by 180 degrees; the maximum winding pair number of each phase is Kpm =Z/(2 m), the tail ends of adjacent windings of each phase are connected in series to form a branch, the tail ends of adjacent windings which are symmetrically distributed at 180 degrees are connected in series to form another branch, two symmetrical branches are connected to form 180-degree symmetrical parallel branches, and the parallel principle is that: when the pole pair number P is even, the two symmetrical branch windings are connected in parallel according to the head end and the tail end, and when the pole pair number P is odd, the two symmetrical branch windings are connected in parallel according to the head end and the tail end; one end of the parallel branch winding is used as the midpoint of the phase winding, and the other end of the parallel branch winding is used as the phase port; thereby creating three-phase ports for three-phase windings and midpoints for one three-phase winding.

Preferably, the rotor pole pair number p=10 or p=14, the tooth groove number z=12, and the phase number m=3.

Preferably, each phase winding forms one or more pairs of 180 ° symmetrical parallel branches.

Preferably, the motor stator core is divided into a plurality of segments, and the stator core segment gap λd=δk ₁ Wherein δ is the electromagnetic air gap of the motor, rotor core segment gap λr=λd, K ₁ As a first coefficient, K ₁ The value of (2) is 1 to 2.

Preferably, the rotor core segment gaps at both ends in the rotor axial direction are: λrd=k ₂ λr1＝K ₂ λd, wherein λr1 is a rotor core segment excluding both ends in the rotor axial directionA rotor core segment gap remaining beyond the gap; λd is the stator core segment gap, K ₂ Is the second coefficient, K ₂ The value of (2) is 1.5 to 2.

Preferably, when λd or λr is smaller than 4 to 5 times of the axial length of each segment, the axial magnetic levitation rigidity is approximately proportional to the number of segments n, the maximum rigidity of the axial passive magnetic levitation after the segments is approximately 0.95nK, and the axial effective working range of the magnetic levitation is approximately 0.95 λd or 0.95 λr, wherein K is the rigidity of the single-segment axial passive magnetic levitation.

Preferably, the rotor permanent magnet is realized by samarium cobalt magnetic steel.

Preferably, the number of segments of the stator core and the number of segments of the rotor core are each 5.

The beneficial effects brought by the invention are as follows:

the invention does not need any additional sensor or controller, changes the traditional mechanical bearing into an additional protection bearing with a gap of 0.1-0.5 mm, and can adapt to heavy load and all-weather limit environment. The invention naturally comprises: the radial active natural magnetic suspension technology and the axial passive magnetic suspension technology have excellent motor driving functions.

The present invention has the advantages of simplicity and reliability, which are all of principle, namely the naturally owned advantages, simplicity and reliability.

The invention breaks through the application problem of the limit temperature difference environment and eliminates the problem that the mechanical bearing in the limit environment is damaged, stuck or worn due to expansion and contraction of heat. The motor of the invention can be used in large mechanical equipment in a space limit environment and is used for: a satellite out-of-cabin manipulator (robot), a power generation system and an energy storage system used in a space limit environment, and the like. For use in earth-limited environments such as: nuclear radioactive environments, extreme temperature differential environments, sudden hazardous environments, and the like. Is prepared for the development of future spacecraft in China.

Drawings

FIG. 1 is an axial sectional view of a natural electromagnetic magnetic levitation three-phase permanent magnet synchronous motor in a limit environment according to the invention; wherein reference numeral 6 is a stator core segment gap, and reference numeral 7 is a rotor core segment gap;

FIG. 2 is a schematic diagram of a three-phase winding of a motor with 10 poles and 12 slots according to the present invention; wherein each phase has 1 pair of parallel branches;

FIG. 3 is a schematic diagram of a three-phase winding of a motor with 14 poles and 12 slots according to the present invention; wherein each phase has 1 pair of parallel branches;

FIG. 4 is a schematic diagram of a three-phase winding of a motor with 10 poles and 12 slots according to the present invention; wherein each phase has 1 pair of parallel branches;

FIG. 5 is a schematic diagram of a three-phase winding of a motor with 10 poles and 12 slots according to the present invention; wherein each phase has 2 pairs of parallel branches.

FIG. 6 is a schematic diagram of a three-phase winding of a motor with 10 poles and 12 slots according to the present invention; wherein each phase has 1 pair of parallel branches and a pair of short-circuited windings.

In fig. 2 to 6, reference symbol O denotes a midpoint of each phase winding, that is, a midpoint of the three-phase winding.

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 first embodiment, referring to fig. 1, the limit environment natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor according to the embodiment is a fractional slot concentrated winding motor, the ratio of the number of slots to the number of phases of the motor is Z/m, Z/m is an even number, each phase winding of the motor forms windings symmetrically distributed along the circumference by 180 degrees, and force couple moment symmetrical by 180 degrees is generated; the motor comprises a rotor and a stator sleeved outside the rotor, and the stator is fixed on the stator shell 5;

the rotor comprises a rotor core 3 and rotor permanent magnets 4; the rotor permanent magnet 4 is arranged on the rotor core 3, and the starting protection mechanical bearing clearance at the end part of the rotor core 3 is 0.1mm to 0.5mm;

the stator comprises a stator core 1 and a stator winding 2; the stator winding 2 is wound on the stator core 1, the stator core 1 is axially divided into three or more sections, and gaps exist between two adjacent sections; the stator winding 2 is a three-phase winding;

the stator winding 2 is divided into a plurality of pairs of windings symmetrically distributed along the circumference by 180 degrees; the maximum winding pair number of each phase is Kpm =Z/(2 m), the tail ends of adjacent windings of each phase are connected in series to form a branch, the tail ends of adjacent windings which are symmetrically distributed at 180 degrees are connected in series to form another branch, two symmetrical branches are connected to form 180-degree symmetrical parallel branches, and the parallel principle is that: when the pole pair number P is even, the two symmetrical branch windings are connected in parallel according to the head end and the tail end, and when the pole pair number P is odd, the two symmetrical branch windings are connected in parallel according to the head end and the tail end; one end of the parallel branch winding is used as the midpoint of the phase winding, and the other end of the parallel branch winding is used as the phase port; the three-phase windings of the motor form 180 ° symmetrical parallel branches, respectively, so that three-phase ports of the three-phase windings and midpoints of one three-phase winding are produced. Finally, special 180-degree symmetrical parallel branch three-phase windings are formed. The invention has one or more pairs of 180 DEG symmetrical parallel branches for each phase winding, and the currents in the 180 DEG symmetrical parallel branches are the same in principle when the stator and rotor air gaps are not deviated.

Further, each phase winding forms one or more pairs of 180 ° symmetrical parallel branches. In order to obtain an axial passive magnetic levitation capability, the stator winding 2 does not have to be segmented with the stator core 1.

When the motor is applied, attractive force exists between the stator iron core 1 and the rotor permanent magnet 4, 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 radial attractive force in the air gap of the motor is equal everywhere and counteracts each other through the bearing. However, if the motor rotates and the bearing fails, when the air gap at the two sides of 180 degrees is deviated, the permanent magnet rotor body is sucked to the side with the small air gap, the counter potential of the parallel branch at the side with the small air gap is increased, the current is decreased, the counter potential of the parallel branch at the side with the large air gap is decreased, 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 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 invention has the capability of radial natural magnetic suspension recovery centering. The invention uses the starting protection mechanical bearing because the permanent magnet rotor body is randomly sucked to the side with small air gap when the motor is not started and the radial instability of the permanent magnet rotor body when the motor is not started. Under the condition of no sensor or controller, the invention adopts the traditional motor driving method to have perfect dynamic radial natural electromagnetic magnetic suspension and passive axial magnetic suspension functions.

Further, the rotor pole pair number p=10 or p=14, the tooth groove number z=12, and the phase number m=3. And Z/m=12/3=4 is an even number, so that each phase winding of the motor can form windings which are symmetrically distributed along the circumference by 180 degrees, and can generate 180-degree symmetrical couple moment, and p=10 or p=14, the stator pole number (tooth slot number) z=12, the phase number m=3, and the windings of the two rotor pole pair motors are connected identically.

Further, referring specifically to fig. 2 and 3, in this embodiment, when the pair number of rotor poles p=10 or p=14, Z/m=12/3=4, each phase winding of the stator winding 2 has 4 groups of winding elements, wherein the 4 groups of windings are divided into Kpm =z/(2 m) =2 pairs of windings symmetrically distributed along the circumference 180 °, each group has 2 adjacent windings, the winding tails are connected in series, the 2 adjacent windings are connected in series to form a branch, and the other branch is formed by 2 windings in the group symmetrically distributed along the circumference 180 °; the other three groups of windings of the phase are all similar in the same way: connecting each group of adjacent 2 windings in series, wherein the winding tails are connected in series, and the adjacent 2 windings are connected in series to form a branch; the three groups of windings which are 180 DEG symmetrically distributed with the other three groups of windings of the phase respectively form another branch, and then the two symmetrical branches formed by the two groups of windings which are 180 DEG symmetrically distributed are connected into a parallel branch; the parallel principle is as follows: when the pole pair number P is even, the two parallel branch windings are connected in parallel according to the head-tail, when the pole pair number P is odd, the two parallel branch windings are connected in parallel according to the head-head and the tail-tail, and one end of the two parallel branch windings is used as the midpoint of the phase winding; the invention P is even, two parallel branch windings are connected in parallel according to the head-tail, the U-phase winding of the invention has a pair of 180-degree symmetrical parallel branches, a midpoint and a U-phase winding port; similarly, three-phase windings of the motor are respectively formed into 180-degree symmetrical parallel branches according to the method; and U, V, W three-phase ports constituting three-phase windings and a midpoint of one three-phase winding. Namely, the special parallel branch three-phase windings which are symmetrically connected in parallel at 180 degrees are finally formed.

The invention has one or more pairs of 180 DEG symmetrical parallel branches for each phase winding, and the currents in the 180 DEG symmetrical parallel branches are the same in principle when the stator and rotor air gaps are not deviated. As is well known, there is an attractive force between the stator core 1 and the rotor permanent magnets 4, which, due to the action of the bearings, keeps the air gap between the stator and the rotor equal, the attractive forces being equal everywhere along the circumference, the bearings making the radial attractive forces within the motor air gap equal everywhere and counteracting 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, the counter potential of the parallel branch at the side with small air gap is inevitably increased, and the current is reduced; in contrast, the counter potential of the parallel branch on the side with the large air gap becomes smaller, the current becomes larger, the radial pulling force on the side with the large air gap becomes larger, the radial pulling force on the side with the small air gap becomes smaller, the air gap is inevitably changed in the direction of smaller deviation, and the air gap deviation is stabilized. Therefore, after the motor rotates, the invention has the capability of radial natural magnetic suspension recovery centering.

In this embodiment, when Z/m=12/3=4, the rotor pole pair number p=10, and each phase winding of the stator winding 2 has 4 groups of winding elements, each group has 2 adjacent windings, the three-phase winding of the motor is specifically shown in fig. 2. When Z/m=12/3=4, the rotor pole pair number p=14, and each phase winding of the stator winding 2 has 4 groups of winding elements, each group having 2 adjacent windings, the motor three-phase winding is wound with particular reference to fig. 2.

Further, referring specifically to fig. 4 for describing the preferred embodiment, when the pole pair number p=10, Z/m=12/3=4 of the rotor, each phase winding of the stator winding 2 has 4 groups of winding elements, and is divided into Kpm =z/(2 m) =2 pairs of windings symmetrically distributed along the circumference 180 °, each group has only 1 winding, one branch, and the group symmetrically distributed with the group 180 ° forms another branch; similarly, the other three groups of windings of the phase are also adjacent and have 1 winding, one branch and the three groups of windings which are 180 DEG symmetrically distributed with the other three groups of windings of the phase respectively form the other branch; then connecting two symmetrical branches formed by two groups of windings symmetrically distributed at 180 degrees into parallel branch windings; the parallel principle is as follows: when the pole pair number P is even, the two parallel branch windings are connected in parallel according to the head-tail, when the pole pair number P is odd, the two parallel branch windings are connected in parallel according to the head-head and the tail-tail, and one end of the two parallel branch windings is used as the midpoint of the phase winding; the invention P is even, two parallel branch windings are connected in parallel according to the head-tail, the U-phase winding of the invention has a pair of 180-degree symmetrical parallel branches, a midpoint and a U-phase winding port; similarly, three-phase windings of the motor are respectively formed into 180-degree symmetrical parallel branches according to the method; and U, V, W three-phase ports constituting three-phase windings and a midpoint of one three-phase winding. Namely, the special parallel branch three-phase windings which are symmetrically connected in parallel at 180 degrees are finally formed.

The invention has one or more pairs of 180 DEG symmetrical parallel branches for each phase winding, and the currents in the 180 DEG symmetrical parallel branches are the same in principle when the stator and rotor air gaps are not deviated.

When the motor is applied, attractive force exists between the stator iron core 1 and the rotor permanent magnet 4, 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 radial attractive force in the air gap of the motor is equal everywhere and counteracts each other through the bearing. 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, the counter potential of the parallel branch at the side with small air gap is inevitably increased, and the current is reduced; in contrast, the counter potential of the parallel branch on the side with the large air gap becomes smaller, the current becomes larger, the radial pulling force on the side with the large air gap becomes larger, the radial pulling force on the side with the small air gap becomes smaller, the air gap is inevitably changed in the direction of smaller deviation, and the air gap deviation is stabilized. Therefore, after the motor rotates, the invention has the capability of radial natural magnetic suspension recovery centering.

Further, referring specifically to fig. 5, in the preferred embodiment, when the pole pair number p=10, Z/m=12/3=4 of the rotor, each phase winding of the stator winding 2 has 4 groups of winding elements, and is divided into Kpm =z/(2 m) =2 pairs of windings symmetrically distributed along the circumference 180 °, each group has 2 windings, two branches, and two windings in the group symmetrically distributed with the 180 ° of the group form another two branches; similarly, the other three groups of windings of the phase are 2 windings, two branches and the three groups of windings which are 180 DEG symmetrically distributed with the other three groups of windings of the phase respectively form the other two branches; then connecting every two symmetrical branches formed by two groups of windings which are symmetrically distributed at 180 degrees into parallel branch windings; the parallel principle is as follows: when the pole pair number P is even, the two parallel branch windings are connected in parallel according to the head-tail, when the pole pair number P is odd, the two parallel branch windings are connected in parallel according to the head-head and the tail-tail, and one end of the two parallel branch windings is used as the midpoint of the phase winding; the invention has even number of windings of two parallel branches connected in parallel from head to tail.

The U-phase winding of the invention is provided with two pairs of 180-degree symmetrical parallel branches, a midpoint and a U-phase winding port; similarly, three-phase windings of the motor are respectively formed into 180-degree symmetrical parallel branches according to the method; and U, V, W three-phase ports constituting three-phase windings and a midpoint of one three-phase winding. Namely, the special parallel branch three-phase windings which are symmetrically connected in parallel at 180 degrees are finally formed.

In the preferred embodiment, there is an attractive force between the stator core 1 and the rotor permanent magnets 4, which is maintained equal to the air gap between the stator and the rotor due to the action of the bearings, which equalizes everywhere circumferentially and the bearings equalize and cancel each other out the radial attractive forces within the motor air gap. 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, the counter potential of the parallel branch at the side with small air gap is inevitably increased, and the current is reduced; in contrast, the counter potential of the parallel branch on the side with the large air gap becomes smaller, the current becomes larger, the radial pulling force on the side with the large air gap becomes larger, the radial pulling force on the side with the small air gap becomes smaller, the air gap is inevitably changed in the direction of smaller deviation, and the air gap deviation is stabilized. Therefore, after the motor rotates, the invention has the capability of radial natural magnetic suspension recovery centering.

Still further, referring specifically to fig. 6, the preferred embodiment is illustrated, when the pole pair number p=10, Z/m=12/3=4 of the rotor, each phase winding of the stator winding 2 has 4 groups of winding elements, and is divided into Kpm =z/(2 m) =2 pairs of windings symmetrically distributed along the circumference 180 °, each group has only 1 winding, one branch, and similarly, other three groups of windings of this phase have only 1 winding, one branch; then connecting two symmetrical branches formed by two groups of windings symmetrically distributed at 180 degrees into parallel branch windings; the parallel principle is as follows: when the pole pair number P is even, the two parallel branch windings are connected in parallel according to the head-tail, when the pole pair number P is odd, the two parallel branch windings are connected in parallel according to the head-head and the tail-tail, and one end of the two parallel branch windings is used as the midpoint of the phase winding; the invention P is even, two parallel branch windings are connected in parallel according to the head-tail, the U-phase winding of the invention has a pair of 180-degree symmetrical parallel branches, a midpoint and a U-phase winding port; similarly, three-phase windings of the motor are respectively formed into 180-degree symmetrical parallel branches according to the method; and U, V, W three-phase ports constituting three-phase windings and a midpoint of one three-phase winding. Namely, the special parallel branch three-phase windings which are symmetrically connected in parallel at 180 degrees are finally formed.

The attractive force exists between the stator core 1 and the rotor permanent magnet 4, 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 radial attractive force in the air gap of the motor is equal everywhere and counteracts each other through the bearing. 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, the counter potential of the parallel branch at the side with small air gap is inevitably increased, and the current is reduced; in contrast, the counter potential of the parallel branch on the side with the large air gap becomes smaller, the current becomes larger, the radial pulling force on the side with the large air gap becomes larger, the radial pulling force on the side with the small air gap becomes smaller, the air gap is inevitably changed in the direction of smaller deviation, and the air gap deviation is stabilized. Therefore, after the motor rotates, the invention has the capability of radial natural magnetic suspension recovery centering. In order to increase the natural magnetic levitation restoring force, a short-circuit winding special for improving the natural magnetic levitation restoring force is added to each adjacent empty slot in the invention shown in fig. 6. Based on the same principle, attractive force exists between the stator core 1 and the rotor permanent magnet 4, the air gap between the stator and the rotor is kept equal due to 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, 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.

Further, the motor stator core 1 is divided into a plurality of segments, and the stator core segment gap λd= (1-2) δ, wherein δ is the electromagnetic air gap of the motor, and the rotor core segment gap λr=λd. Due to the axial segmentation of the rotor, a segmentation gap exists in the rotor.

Further, the rotor core segment gaps at the two ends of the rotor axial direction are as follows: λrd= (1.5-2) λr1= (1.5-2) λd, wherein λr1 is a rotor core segment gap remaining except for rotor core segment gaps at both ends in the rotor axial direction; λd is the stator core segment gap.

Further, when λd or λr is smaller than 4 to 5 times of the axial length of each segment, the axial magnetic levitation rigidity is approximately proportional to the number n of segments, the maximum rigidity of the axial passive magnetic levitation after the segments is approximately 0.95nK, and the axial effective working range of the magnetic levitation is approximately 0.95 λd or 0.95 λr, wherein K is the rigidity of the single-segment axial passive magnetic levitation.

Furthermore, the rotor permanent magnet 4 is realized by adopting samarium cobalt magnetic steel.

Further, the number of segments of the stator core 1 and the number of segments of the rotor core 3 are 5.

The radial natural electromagnetic magnetic suspension technology is adopted, and the axial passive magnetic suspension and auxiliary mechanical bearing are adopted. The volume, loss and cost are completely eliminated.

In order to further improve the reliability, the invention is additionally provided with a special mechanical auxiliary bearing so as to adapt to large load and all-weather limit environment.

The invention does not need any additional sensor or controller, changes the traditional mechanical bearing into an additional protection bearing with a gap of 0.1 mm-0.5 mm, and can adapt to heavy load and all-weather limit environment. The invention naturally comprises: the radial active natural magnetic suspension technology and the axial passive magnetic suspension technology have excellent motor driving functions. The heating source of the inner rotor motor is arranged at the stator side, and the rotor does not generate heat, so that the inner rotor motor is insensitive to a vacuum limit environment and can work in all weather.

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

1. The motor is a fractional slot concentrated winding motor, the ratio of the number of tooth slots to the number of phases of the motor is Z/m, and Z/m is an even number, and the motor is characterized in that each phase of winding of the motor forms windings which are symmetrically distributed along the circumference by 180 degrees and generate couple moment which is 180 degrees symmetrically; the motor comprises a rotor and a stator sleeved outside the rotor, and the stator is fixed on a stator shell (5);

the rotor comprises a rotor core (3) and rotor permanent magnets (4); the rotor permanent magnet (4) is arranged on the rotor core (3), and the starting protection mechanical bearing clearance at the end part of the rotor core (3) is 0.1mm to 0.5mm;

the stator comprises a stator core (1) and a stator winding (2); the stator winding (2) is wound on the stator core (1), the stator core (1) is axially divided into three or more sections, and gaps exist between two adjacent sections; the stator winding (2) is a three-phase winding;

the stator winding (2) is divided into a plurality of pairs of windings symmetrically distributed along the circumference by 180 degrees; the maximum winding pair number of each phase is Kpm =Z/(2 m), the tail ends of adjacent windings of each phase are connected in series to form a branch, the tail ends of adjacent windings which are symmetrically distributed at 180 degrees are connected in series to form another branch, two symmetrical branches are connected to form 180-degree symmetrical parallel branches, and the parallel principle is that: when the pole pair number P is even, the two symmetrical branch windings are connected in parallel according to the head end and the tail end, and when the pole pair number P is odd, the two symmetrical branch windings are connected in parallel according to the head end and the tail end; one end of the parallel branch winding is used as the midpoint of the phase winding, and the other end of the parallel branch winding is used as the phase port; thereby creating three-phase ports for three-phase windings and midpoints for one three-phase winding.

2. The extreme environment natural electromagnetic levitation three-phase permanent magnet synchronous motor according to claim 1, wherein the rotor pole pair number p=10 or p=14, the tooth slot number z=12, and the phase number m=3.

3. The extreme environment natural electromagnetic levitation three-phase permanent magnet synchronous motor of claim 1, wherein each phase winding forms one or more pairs of 180 ° symmetrical parallel branches.

4. The extreme environment natural electromagnetic levitation three-phase permanent magnet synchronous motor of claim 1, wherein stator core segment gap λd = δk ₁ Wherein δ is the electromagnetic air gap of the motor, rotor core segment gap λr=λd, K ₁ As a first coefficient, K ₁ The value of (2) is 1 to 2.

5. The extreme environment natural electromagnetic magnetic levitation three-phase permanent magnet synchronous motor according to claim 1, wherein the rotor core sectional gaps at both ends of the rotor axis direction are: λrd=k ₂ λr1＝K ₂ λd, wherein λr1 is a rotor segment gap remaining except for the rotor segment gaps at both ends in the rotor axial direction; λd is the stator core segment gap, K ₂ Is the second coefficient, K ₂ The value of (2) is 1.5 to 2.

6. The limited environment natural electromagnetic levitation three-phase permanent magnet synchronous motor of claim 4, wherein when λd or λr is less than 4 to 5 times the axial length of each segment, the axial magnetic levitation stiffness is approximately proportional to the number of segments n, the maximum stiffness of the axial passive magnetic levitation after segmentation is approximately 0.95nK, and the axial effective working range of the magnetic levitation is approximately 0.95 λd or 0.95 λr, wherein K is the stiffness of the single-segment axial passive magnetic levitation.

7. The limit environment natural electromagnetic magnetic suspension three-phase permanent magnet synchronous motor according to claim 1, wherein the rotor permanent magnet (4) is realized by samarium cobalt magnetic steel.

8. The limit environment natural electromagnetic levitation three-phase permanent magnet synchronous motor according to claim 4, wherein the number of segments of the stator core (1) and the number of segments of the rotor core (3) are 5.