A linear induction motor for medium and low speed maglev trains

Abstract

The invention discloses a linear induction motor for medium and low speed maglev trains, wherein one surface of the stator core is provided with a core tooth slot; a double-layer short-pitch stacked winding is fixed in the core tooth slot; an iron core extension structure is respectively arranged at both ends of the stator core; the iron core extension structure comprises a single-layer full-pitch winding; the single-layer full-pitch winding is fixed in an upper slot and a lower slot opened on two opposite surfaces of the iron core extension structure; the value range of the initial phase θ of the winding coil at the end of the single-layer full-pitch winding is [(nπ‑60°)‑(L / τ)*π] to [(nπ+60°)‑(L / τ)*π], where L is the spacing between adjacent motors, n is an odd number greater than or equal to 1, and θ is a multiple of 60 degrees. After the extension structure is added to the scheme, the spacing between adjacent linear induction motors is less than the length of the pole pitch of two motors, which effectively compensates for the traction loss caused by the longitudinal end effect of the linear induction motor at high speed.

Description

Technical Field

[0001] The invention relates to the field of medium and low speed magnetic levitation linear induction motors, and in particular to a medium and low speed magnetic levitation train linear induction motor. Background Art

[0002] Medium and low-speed maglev trains generally use single-sided linear induction motors as drive motors, and their operating speed is 100 to 120 kilometers. When single-sided linear induction motors are used in medium and low-speed maglev train technology, the secondary induction plate is laid on the F rail, and the material is generally selected as aluminum plate. The primary is installed under the train suspension bogie. The primary is connected to the three-phase alternating current to generate a three-phase traveling wave magnetic field in the air gap, and the induced current formed in the secondary induction plate interacts with the air gap magnetic field to generate forward thrust. However, as the motor speed increases, the longitudinal end effect of the linear induction motor becomes more and more obvious. The longitudinal end effect weakens the magnetic field at the input end of the single-sided linear induction motor, and the air gap magnetic field in the motor outlet area has an obvious tailing effect. The weakening of the air gap magnetic field in the effective area of ​​the motor weakens the traction of the motor, and as the speed increases, the degree of magnetic field weakening in the motor inlet area increases, and the loss of traction also increases. Therefore, this phenomenon brings great difficulties to the speed increase of medium and low-speed maglev trains.

[0003] Medium and low speed maglev trains are equipped with multiple linear induction motors. According to the characteristics of the longitudinal end effect, when the speed is high, if the distance between two adjacent motors is between one motor pole pitch and two motor pole pitches and the phase of the primary windings of the two motors is at a suitable phase difference, the tailing effect of the tail of the running front motor can enhance the air gap magnetic field between the two motors. The air gap magnetic field of the motor gap can compensate for the weakening of the air gap magnetic field caused by the longitudinal end effect of the running rear motor, and the air gap magnetic field of the rear motor is enhanced, thereby increasing the traction of the rear motor. However, due to the limitations of the suspension frame structure of the current medium and low speed maglev trains, the distance between two adjacent motors is large and cannot meet the above distance requirements. Therefore, the existing ordinary linear induction motors are greatly affected by the end effect at high speeds and cannot utilize the tailing effect.

[0004] In summary, with regard to the speed-up problem of medium and low speed maglev trains, the longitudinal end effect of existing single-sided linear induction motors will bring difficulties to the speed-up. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the medium- and low-speed maglev train linear induction motor provided by the present invention solves the problem that ordinary linear induction motors are greatly affected by the end effect at high speeds and cannot utilize the tail effect.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] Provided is a linear induction motor for a medium- and low-speed maglev train, comprising a stator core, a double-layer short-pitch stacked winding and a core extension structure; one surface of the stator core is provided with a core tooth slot 9; the double-layer short-pitch stacked winding is fixed in the core tooth slot; two ends of the stator core are respectively provided with a core extension structure; the core extension structure comprises a single-layer full-pitch winding; the single-layer full-pitch winding is fixed in an upper slot and a lower slot provided on two opposite surfaces of the core extension structure; the value range of the initial phase θ of the winding coil at the end of the single-layer full-pitch winding is [(nπ-60°)-(L / τ)*π] to [(nπ+60°)-(L / τ)*π], L is the spacing between adjacent motors, n is an odd number greater than or equal to, and θ is a multiple of 60 degrees.

[0008] The motor winding is three-phase electricity. The current is input from the winding coil on the extended structure of the iron core, passes through the single-layer full-pitch stacked winding at one end, flows into the double-layer short-pitch stacked winding of the motor, and then flows into the single-layer full-pitch winding of the extended structure at the other end of the motor through the double-layer short-pitch stacked winding.

[0009] The beneficial effects of the present invention are as follows: by adding extension structures at both ends of the linear induction motors of medium and low speed maglev trains, the spacing between adjacent linear induction motors is made less than the length of two motor pole pitches; after the initial phase adjustment, it can be ensured that the tail effect wave generated in the outlet area of ​​the running front motor has a phase that is substantially the same as the phase of the air gap magnetic field in the inlet area of ​​the rear motor, thereby compensating for the air gap magnetic field in the inlet area of ​​the rear motor, thereby enhancing the air gap magnetic field of the rear motor, thereby effectively compensating for the traction loss caused by the longitudinal end effect of the linear induction motor at high speed, and improving the traction of the rear motor.

[0010] Furthermore, the depth of the upper and lower slots is less than the depth of the core tooth slots; the tooth slots of the upper and lower slots have the same shape. The slot depth of the upper and lower slots is less than the slot depth of the core tooth slots, mainly because the windings in the core extension structure are single-layer windings, while the core tooth slots are double-layer short-pitch stacked windings. The equivalent current passing through the upper and lower slots is half of that in the core tooth slots. The change in slot size will affect the performance of the motor. The tooth width ratio of the upper and lower slots is consistent with that of the core tooth slots. If the slot depth is too long, the height of the core yoke will become narrower, and if the yoke height is too narrow, the core will be oversaturated.

[0011] Furthermore, the phase sequence of a phase winding of a single-layer full-pitch winding adjacent to a double-layer short-pitch stacked winding is opposite to the phase sequence of a phase winding of a double-layer short-pitch stacked winding adjacent to it. The magnetic pole direction of the winding on the core extension structure needs to be opposite to the magnetic pole of the stator core end winding, so as to exert the function of the linear induction motor.

[0012] Furthermore, the number of empty slots N at the connection between one end of the core extension structure and the side end of the non-extended structure is M*(1-y), where y is the pitch of the double-layer short-pitch stacked winding, and M is the number of slots of a pair of magnetic poles of the motor. Due to the influence of the structure of the double-layer short-pitch stacked winding on the linear motor, there will be M*y half-filled slots with only one layer of coils at both ends of the core slots. The half-filled slots at both ends of the core slots include two types: the upper layer without windings and the lower layer without windings. The purpose of adding empty slots to a section of the core extension structure is to make the number of empty slots without windings on the upper layer or the lower layer of the motor equal to the number of slots M of one pole of the motor, so as not to change the phase sequence of the air gap magnetic field, so M(1-y) empty slots need to be added at one end.

[0013] Furthermore, the coils of the double-layer short-pitch stacked winding are placed in the upper and lower layers of different slots respectively, the wire rods of the front and rear coils are stacked up and down at the ends, and the pitch of the two adjacent front and rear coils is smaller than the pole pitch. The double-layer short-pitch stacked winding can balance the high-order harmonics of the air gap magnetic field of the motor due to its short-pitch structure. The single-layer full-pitch winding structure in the present invention is mainly to reduce the lateral width of both sides of the motor, so that without changing the original suspension frame structure, the motor can be extended into the gap between the lateral end of the suspension frame and the track, so that the distance between two adjacent motors of the train is less than twice the length of the motor pole pitch.

[0014] Furthermore, the length of the core extension structure is equal to the motor pole pitch. According to the characteristics of the longitudinal end effect, at a high speed, if the spacing between two adjacent motors is between one motor pole pitch and two motor pole pitches, and the phase of the primary winding of the rear motor plus the phase corresponding to the spacing between the two motors is not much different from the phase of the previous primary winding, the tailing effect of the rear of the running front motor can enhance the air gap magnetic field between the two motors.

[0015] Furthermore, the spacing L between two adjacent linear induction motors on the F track of the medium-low speed maglev train is less than the pole pitch length of the two linear induction motors. According to the spacing L between adjacent motors, the initial phase of the winding coil is changed by changing the sequence of the winding coils of the next motor, thereby changing the initial phase θ of the winding of the next motor, so that θ+(L / τ)*π≈nπ, that is, [(nπ-60°)-(L / τ)*π]≤θ≤[(nπ+60°)-(L / τ)*π], n is an odd number greater than or equal to 1, and in order to facilitate the distribution of the phase sequence of the winding of the next motor, θ is a multiple of 60 degrees. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required in the embodiments or the description of the prior art are briefly introduced below.

[0017] Figure 1 This is a schematic diagram of a linear induction motor for a medium and low speed maglev train;

[0018] Figure 2 It is a schematic diagram of the stator core and the extended core structure;

[0019] Figure 3 It is a schematic diagram of the double-layer short-distance stacked winding structure;

[0020] Figure 4 It is a schematic diagram of a single-layer full-pitch winding structure;

[0021] Figure 5 It is a schematic diagram of the phase sequence of the winding coil at the connection between the core extension structure and the stator core;

[0022] Figure 6 A cross-sectional diagram of the installation of a linear induction motor for a medium- and low-speed maglev train;

[0023] Figure 7 This is a schematic diagram of the installation of a linear induction motor;

[0024] Figure 8 It is a schematic diagram of the structure of a common linear induction motor;

[0025] Fig. 9 It is a comparison curve diagram of the traction forces of a common linear induction motor, a front motor of the linear induction motor of the present invention, and a rear motor of the linear induction motor of the present invention;

[0026] In the figure, 1-stator core, 2-double-layer short-pitch stacked winding, 3-core extension structure, 301-single-layer full-pitch winding, 302-upper slot, 303-lower slot, 4-winding coil, 401-winding section one, 402-winding section two, 403-winding section three, 501-pole one, 502-pole two, 503-pole three, 504-pole four, 6-empty slot, 701-suspension frame, 702-suspension frame support arm, 703-F rail, 704-support wheel, 801-motor one, 802-motor two. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0028] like Figure 1 and Figure 2As shown, the linear induction motor for medium and low speed maglev trains provided by the present solution comprises a stator core 1, a double-layer short-pitch stacked winding 2 and a core extension structure 3; one surface of the stator core 1 is provided with a core tooth slot 9; the double-layer short-pitch stacked winding 2 is fixed in the core tooth slot 9; a core extension structure 3 is respectively arranged at both ends of the stator core 1; the core extension structure 3 comprises a single-layer full-pitch winding 301; the single-layer full-pitch winding 301 is fixed in an upper slot 302 and a lower slot 303 opened on two opposite surfaces of the core extension structure 3; the value range of the initial phase θ of the winding coil 4 at the end of the single-layer full-pitch winding 301 is [(nπ-60°)-(L / τ)*π]~[(nπ+60°)-(L / τ)*π], n is an odd number greater than or equal to 1, and θ is a multiple of 60 degrees.

[0029] like Figure 4 As shown, the motor winding is three-phase electricity, and the current is input from the winding coil 4 on the core extension structure 3, passes through the single-layer full-pitch stacked winding 301 at one end, flows into the double-layer short-pitch stacked winding 2, and flows into the single-layer full-pitch winding 301 of the extended structure at the other end of the motor through the double-layer short-pitch stacked winding 2. The winding coil 4 of each phase of the core extension structure 3 is wound in the upper slot 302 and the lower slot, and the winding order is determined according to the phase sequence of the motor winding: winding from the lower slot 303 to the upper slot or winding from the upper slot 302 to the lower slot. The current of the winding coil 4 flows out from the winding section 1 401, the winding section 2 402 and the winding section 3 403 respectively. Since the current inflow position of the winding coil 4 located at the right end in the figure is on the back of the winding section 3 403, the winding coil 4 is wound from the bottom to the top, so there is an empty slot on the core extension structure 3.

[0030] This solution forms a new linear induction motor by adding extension structures at both ends of the linear induction motor of the medium and low speed maglev train. On the basis of the existing suspension frame structure, the iron core extension structure 3 extends into the gap between the two ends of the suspension frame and the track. When multiple linear induction motors for medium and low speed maglev trains are installed under the suspension frame of the medium and low speed maglev train, the spacing between the linear induction motors for the medium and low speed maglev trains is less than the length of the two motor poles.

[0031] The initial phase θ of the rear motor winding is changed to make θ+(L / τ)*π≈nπ, that is, [(nπ-60°)-(L / τ)*π] ≤θ≤[(nπ+60°)-(L / τ)*π], n is an odd number greater than or equal to 1, and according to the phase band of the motor winding, θ is a multiple of 60 degrees, so that the tail effect wave generated in the exit area of ​​the front motor is basically the same as the phase of the air gap magnetic field in the entrance area of ​​the rear motor, so that the air gap magnetic field in the entrance area of ​​the rear motor can be compensated, so that the air gap magnetic field of the rear motor is enhanced, thereby effectively compensating for the traction loss caused by the longitudinal end effect of the linear induction motor at high speed, improving the traction of the rear motor, and because of the addition of the extension structure at both ends of the linear induction motor, the motor traction can be further improved. Therefore, the linear induction motor installed on the existing suspension frame structure can effectively improve the motor traction, thereby improving the running speed of medium and low speed maglev trains.

[0032] like Figure 2 As shown, the depth of the upper slot 302 and the lower slot 303 is less than the depth of the core tooth slot 9; the tooth slot shape of the upper slot 302 and the lower slot 303 is the same. The slot depth of the upper slot 302 and the lower slot 303 is less than the slot depth of the core tooth slot 9, mainly because the winding in the core extension structure 3 is a single-layer winding. The core tooth slot 9 is a double-layer short-distance winding. The equivalent current passing through the upper slot 302 and the lower slot 303 is half of that in the core tooth slot 9. The change in the size of the slot will affect the performance of the motor. The tooth width ratio of the upper slot 302 and the lower slot 303 is consistent with that of the slot 9. If the slot depth is too long, the height of the core yoke will become narrower, and if the yoke height is too narrow, the core will be oversaturated.

[0033] In this embodiment, the phase sequence of a phase winding of the single-layer full-pitch winding 301 adjacent to the double-layer short-pitch stacked winding 2 is opposite to the phase sequence of a phase winding of the double-layer short-pitch stacked winding 2 adjacent to it. The magnetic pole direction of the winding on the core extension structure 3 needs to be opposite to the magnetic pole of the end winding of the stator core 1, so as to exert the function of the linear induction motor.

[0034] like Figure 3 As shown, the number of turns of the double-layer short-pitch lap winding 2 used in this embodiment is four. According to the motor parameters used in the embodiment, the number of slots per pole and per phase of the motor is 4.

[0035] like Figure 5As shown, the number of empty slots 6 at the connection between one end of the core extension structure 3 and the edge of the non-extended structure is N=M*(1-y), y is the pitch of the double-layer short-pitch stacked winding 2, and M is the number of slots of a pair of magnetic poles of the motor. Due to the influence of the structure of the double-layer short-pitch stacked winding on the linear motor, there will be M*y half-filled slots with only one layer of coils at both ends of the core tooth slot 9. The half-filled slots at both ends of the core tooth slot 9 include two types: the upper layer without windings and the lower layer without windings. The purpose of adding empty slots 6 to a section of the core extension structure 3 is to make the number of empty slots without windings on the upper layer or the lower layer of the motor equal to the number of slots M of one pole of the motor, so as not to change the phase sequence of the air gap magnetic field, so M(1-y) empty slots 6 need to be added at one end.

[0036] In this embodiment, the coils of the double-layer short-pitch stacked winding 2 are placed in the upper and lower layers of the tooth slots respectively, the wire rods of the front and rear coils are stacked up and down at the ends, and the pitch of the two adjacent front and rear coils is smaller than the pole pitch. The double-layer short-pitch stacked winding can balance the high-order harmonics of the air gap magnetic field of the motor due to its short-pitch structure. The single-layer full-pitch winding structure in the present invention is mainly to reduce the lateral width of both sides of the motor.

[0037] In this embodiment, the length of the core extension structure 3 is equal to one motor pole pitch. According to the characteristics of the longitudinal end effect, at a high speed, if the spacing between two adjacent motors is between one motor pole pitch and two motor pole pitches and the primary winding phase of the rear motor plus the phase corresponding to the spacing between the two motors is not much different from the phase of the previous primary winding, the tailing effect of the tail of the running front motor can enhance the air gap magnetic field between the two motors.

[0038] like Figure 6 and Figure 7As shown, a plurality of linear induction motors for medium and low speed maglev trains are installed under the suspension frame 701 of the medium and low speed maglev train, and the two ends of the motors extend into the gap between the two ends of the suspension frame 701 and the track; the spacing L between two adjacent linear induction motors of the F rail 703 is less than the length of the two motor pole pitches. During installation, the core extension structure 3 can extend into the gap between the lateral end of the suspension frame 701 and the F rail 703. In order to ensure that when the train is running at high speed, the trailing magnetic field of the running front motor 1 801 enhances the magnetic field at the input end of the rear motor 2 802, the spacing L between adjacent motors of the F rail 703 is less than the length of the two motor pole pitches. According to the spacing L between adjacent motors, by changing the sequence of the winding coil 4 of the rear motor (taking a three-phase linear induction motor as an example to illustrate how to change the sequence of the winding coil 4 of the rear motor: the three-phase motor can be represented as A, B, C, X, Y, Z, and the current phase sequences are 60° apart. At this time, the current phase sequence arrangement sequence is A, Z, B, X, C, Y. Assuming that the initial phases of the two adjacent motors differ by 120 degrees, the phase sequence arrangement sequence of the rear motor winding is changed to B, X, C, Y, A, Z), the initial phase of the winding coil 4 is changed, thereby changing the initial phase θ of the second 802 winding of the rear motor, so that θ+(L / τ)*π≈nπ, n is an odd number greater than or equal to 1, and in order to facilitate the distribution of the phase sequence of the rear motor winding, θ is a multiple of 60 degrees.

[0039] The current design speed of the medium-low speed maglev train is 160km / h. The maglev train consists of three carriages, each of which has five motors on one side, and a total of thirty motors on the whole train. Figure 8 As shown, the number of motor poles is 8, the number of motor phases is 3, the number of slots per pole per phase is 4, the winding pitch is 10 / 12, the pole pitch is 225mm, and the motor mechanical air gap is 13mm. The maximum value of the primary current is 450A, the rated line voltage is 220V, the rated slip frequency is 15Hz, the motor spacing L is 680mm, and the ordinary motor in the following text refers to the single-sided linear induction motor. When the ordinary motor is used as a traction motor, it is installed under the suspension frame 701 of the medium and low speed maglev train. Since the ordinary linear induction motor adopts a double-layer short-pitch stacked winding, the lateral width of the motor is greater than the spacing between the suspension frame support arm 702 and the support wheel 704. The two ends of the motor cannot extend into the air gap between the support arms 25 at both ends of the suspension frame and the F rail 703. At this time, the motor spacing L is much larger than the pole pitch of the two motors, so the operation of the front motor has little effect on the rear motor.

[0040] The linear induction motor for medium and low speed maglev train proposed in this embodiment has the same main parameters as ordinary motors, and the whole vehicle has a total of 30 motors. The motor parameters of the present invention are as follows: the number of pairs of non-compensation structure poles is 4, the compensation structure motor has 1 pole at each end, the number of motor phases is 3, the pole pitch is 225mm, the winding pitch is 10 / 12, the number of conductors per slot of the non-extended structure is 6, the number of conductors per slot of the core extension structure 3 is 3, the empty slot 6 is 2 slots added between the stator core 1 and the core extension structure 3, and the mechanical air gap is 13mm; the maximum value of the primary current is 450A, and the rated line voltage is 220V. In this embodiment, the spacing between the two linear induction motors of the medium and low speed maglev train under the suspension frame 701 structure is 230 mm. According to the spacing between the adjacent motor 1 801 and the motor 2 802, the initial phase θ of the winding of the latter motor 29 is changed so that θ+(L / τ)*π≈nπ, where n is an odd number greater than or equal to 1. In order to facilitate the distribution of the phase sequence of the winding of the latter motor, θ is set to 0 at this time.

[0041] like Fig. 9 As shown, the ordinary motor in this embodiment is a single-sided linear induction motor currently used in medium and low speed maglev trains. The single-sided linear induction motor for 160km / h medium and low speed maglev trains has 8 poles, 3 motor phases, 4 slots per pole per phase, a winding pitch of 10 / 12, a pole pitch of 225mm, and a motor mechanical air gap of 13mm; the maximum primary current is 450A, and the rated line voltage is 220V.

[0042] The simulation software in this embodiment is ANSYSMaxwell. When the speed of ordinary linear motor is 0-90km / h, constant current constant slip control is adopted. When the speed is 90km / h-240km / h, constant voltage constant slip control is adopted. When the speed of linear induction motor of low-speed maglev train in the present invention is 0-80km / h, constant current constant slip control is adopted. When the speed is 80km / h-240km / h, constant voltage constant slip control is adopted. The traction characteristic curve of ordinary motor and ordinary motor with compensated magnetic field behind linear induction motor in this solution is compared. Fig. 9 shown.

[0043] from Fig. 9 It can be seen that the traction force of the linear induction motor of this scheme is greater than that of ordinary motors, and the traction force of the linear induction motor of the medium and low speed maglev train is increased by 801 compared with the front motor as the speed increases. When the speed is 200km / h, the traction force of the linear induction motor of the medium and low speed maglev train is increased by 50% compared with the ordinary linear induction motor. On the one hand, it shows that the traction force of the linear induction motor of the medium and low speed maglev train is larger because the length of the linear induction motor itself is larger than that of the ordinary motor; on the other hand, the tailing effect generated by the outlet area of ​​the motor running in the front compensates the air gap magnetic field in the inlet area of ​​the rear motor, so that the traction force of the rear motor is improved.

[0044] In summary, this scheme effectively improves the traction force of the motor by changing the distance between the front and rear linear induction motors, thereby providing a feasible solution for speeding up medium and low-speed maglev trains.

Claims

1. A linear induction motor for medium and low speed maglev trains, characterized in that: The invention comprises a stator core (1), a double-layer short-pitch stacked winding (2) and a core extension structure (3); one surface of the stator core (1) is provided with a core tooth slot (9) for fixing the double-layer short-pitch stacked winding (2); two ends of the stator core (1) are provided with a core extension structure (3); the core extension structure (3) comprises a single-layer full-pitch winding (301), and the single-layer full-pitch winding (301) is fixed in an upper slot (302) and a lower slot (303) provided on two opposite surfaces of the core extension structure (3); the value range of the initial phase θ of the winding coil (4) at the end of the single-layer full-pitch winding (301) is [(nπ-60°)-(L / τ)*π]~[(nπ+60°)-(L / τ)*π], where n is an odd number greater than or equal to 1, L is the spacing between adjacent motors, θ is a multiple of 60 degrees, and τ is the motor pole pitch; The length of the iron core extension structure (3) is equal to the motor pole pitch, and the spacing L between two adjacent linear induction motors of the F rail (703) of the medium- and low-speed maglev train is less than the pole pitch length of the two linear induction motors.

2. The linear induction motor for medium and low speed maglev train according to claim 1, characterized in that: The depths of the upper groove (302) and the lower groove (303) are less than the depth of the iron core tooth groove (9); and the tooth groove shapes of the upper groove (302) and the lower groove (303) are the same.

3. The linear induction motor for medium and low speed maglev train according to claim 2, characterized in that: The phase sequence of a phase winding of a single-layer full-pitch winding (301) adjacent to a double-layer short-pitch stacked winding (2) is opposite to the phase sequence of a phase winding of a double-layer short-pitch stacked winding (2) adjacent to it.

4. The linear induction motor for medium and low speed maglev train according to claim 1, characterized in that: The number of empty slots (6) at the connection between one end of the core extension structure (3) and the side end of the non-extended structure is N=M(1-y), y is the pitch of the double-layer short-pitch lap winding (2), and M is the number of slots in a pair of magnetic poles of the motor.

5. The linear induction motor for medium and low speed maglev train according to claim 1, characterized in that: The coils of the double-layer short-pitch stacked winding (2) are respectively placed on the upper and lower layers of the tooth slots, the front and rear wire bars are stacked up and down at the ends, and the pitch of the two adjacent front and rear coils is smaller than the pole pitch.

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