Thrust fluctuation suppression method for polygonal permanent magnet synchronous linear motor

Abstract

The invention discloses a thrust fluctuation suppression method for a polygonal permanent magnet synchronous linear motor, belongs to the field of permanent magnet motors, and aims at solving the problems that three-phase windings of an existing polygonal permanent magnet synchronous linear motor are asymmetric, and thrust fluctuation is large. Armature windings in different primary modules act with permanent magnets of secondary modules to achieve symmetry, and the method comprises the steps that the armature windings of the four primary modules are independently wound in the respective modules, and then the armature windings of each phase of the four primary modules are connected in series or in parallel to form a phase winding; wherein the armature windings of the two primary modules corresponding to the two long sides of the secondary are arranged in any two of A-B-C, B-C-A and C-A-B; the two short edges are arranged in the same way corresponding to the two short edges of the secondary side and are arranged in the remaining way; and the lamination thickness of the two adjacent primary armatures is twice. The armature winding arrangement mode is that the initial position of the A-B-C primary module is 2k tau, the initial position of the B-C-A is 2k tau-(2tau / 3 * 2P), and the initial position of the C-A-B is 2k tau-(tau / 3 * 2P).

Description

Technical Field

[0001] The invention relates to a thrust fluctuation suppression technology for a polygonal permanent magnet synchronous linear motor, and belongs to the field of permanent magnet motors. Background Art

[0002] Linear motors do not require intermediate transmission mechanisms such as crankshafts and connecting rods, and directly form linear motion. They have the advantages of simple structure, strong flexibility, high precision, and high transmission efficiency, and are receiving more and more attention in the field of linear motion. Among them, polygonal permanent magnet synchronous linear motors have received extensive attention due to their good processing and assembly processability, convenient assembly, variable selection, and strong adaptability.

[0003] The main problem of permanent magnet synchronous linear motors is the asymmetry of the three-phase windings caused by end disconnection, which in turn leads to large thrust fluctuations. This is one of the reasons that limit the application of polygonal permanent magnet synchronous linear motors in practice.

[0004] Conventional polygonal permanent magnet synchronous linear motors Figure 6 As shown, the motor includes four primary modules and one secondary. The four primary modules together form a quadrilateral outline. The secondary is located inside the quadrilateral. There is an air gap between the primary and secondary. The air gap between the secondary and each primary module is the same. The modules are connected by mechanical and electrical connectors. The phases of each primary module are consistent, and the initial positions are all 2kτ. See Figure 8 As shown; the in-phase windings of the four primary modules adopt toroidal windings, see Figure 7 Therefore, in the three-phase winding, there must be two phases whose back electromotive force is different from that of the other phase, which leads to large thrust fluctuations. How to improve the asymmetry of the three-phase winding, reduce the thrust fluctuation of the linear motor, reduce the control difficulty, and improve the system stability is very important for this type of permanent magnet synchronous linear motor. Summary of the invention

[0005] In view of the problems that the three-phase winding of the existing polygonal permanent magnet synchronous linear motor is asymmetric and the thrust fluctuation is large, the present invention provides a method for suppressing the thrust fluctuation of the polygonal permanent magnet synchronous linear motor.

[0006] The present invention discloses a method for suppressing thrust fluctuation of a polygonal permanent magnet synchronous linear motor, wherein the polygonal permanent magnet synchronous linear motor comprises four primary modules and a secondary module, wherein the four primary modules form a quadrilateral outer contour, the secondary module is arranged inside the polygonal outer contour, each primary module has the same air gap as the secondary module, and the longitudinal section of the secondary module is a rectangle;

[0007] The thrust fluctuation suppression method is that the armature windings in different primary modules act on the permanent magnets of the secondary modules respectively to achieve symmetry, and the method includes:

[0008] The armature windings of the four primary modules are wound separately inside the respective modules, and then the armature windings under each phase of the four primary modules are connected in series or in parallel to form a phase winding;

[0009] The armature winding arrangement of the two primary modules corresponding to the two long sides of the secondary is any two of ABC, BCA and CAB; the armature winding arrangement of the two primary modules corresponding to the two short sides of the secondary is the same and is the remaining one;

[0010] The stacking thickness of the armature windings of the two primary modules corresponding to the two long sides of the secondary is D 1 , D 3 The stacking thickness of the armature windings of the two primary modules corresponding to the two short sides of the secondary is D 2 , D 4 ; and there is a relationship: D 1 =D 3 =2D 2 =2D 4 ;

[0011] The initial position of the primary module for the armature winding arrangement ABC is 2kτ, and the initial position of the armature winding arrangement BCA is The initial position of the armature winding arrangement is CAB. k is a positive integer, τ is the secondary permanent magnet pole pitch, and P is the number of permanent magnet pole pairs.

[0012] Preferably, the primary armature winding is a single-layer winding or a double-layer winding.

[0013] Preferably, the core of the primary module is made of silicon steel sheet, amorphous alloy material or soft magnetic composite material.

[0014] Preferably, the secondary module includes a secondary core and a permanent magnet. The secondary core is a rectangular frame structure with openings at both ends. The secondary core is made of magnetic conductive material or non-magnetic conductive material.

[0015] Preferably, the magnetic conductive material of the secondary core is silicon steel sheet, amorphous alloy material or soft magnetic composite material.

[0016] Preferably, the non-magnetic conductive material of the secondary core is aluminum alloy or titanium alloy.

[0017] Preferably, the permanent magnets of the secondary module are parallel magnetized, axial magnetized or Halbach magnetized.

[0018] Preferably, the axial lengths of the four primary modules are the same.

[0019] Beneficial effects of the present invention:

[0020] 1. The present invention makes the three-phase winding symmetrical from the motor end side by matching the corresponding primary structure, reasonable winding arrangement and reasonable primary and secondary relative positions, which greatly improves the three-phase back electromotive force imbalance problem caused by the end of the linear motor, and further improves the thrust fluctuation problem of the linear motor.

[0021] 2. The present invention significantly improves the problem of asymmetric three-phase back electromotive force of polygonal permanent magnet synchronous linear motor, reduces thrust fluctuation, and improves system stability. The method has the advantages of simple structure and easy processing and production. It is suitable for short primary and long secondary linear motor applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a structural schematic diagram of a polygonal permanent magnet linear synchronous motor according to the present invention;

[0023] Figure 2 It is a schematic diagram of the structure of a polygonal permanent magnet synchronous linear motor after windings are connected according to the present invention;

[0024] Figure 3 is a schematic diagram of the initial position of the primary armature winding as a single-layer winding, where Figure 3 (a) is a schematic diagram of the initial position of primary module No. 1; Figure 3 (b) is a schematic diagram of the initial positions of the No. 2 and No. 4 primary modules; Figure 3 (c) is a schematic diagram of the initial position of the No. 3 primary module;

[0025] Figure 4 is a schematic diagram of the initial position of the primary armature winding as a double-layer winding, where Figure 4 (a) is a schematic diagram of the initial position of primary module No. 1; Figure 4 (b) is a schematic diagram of the initial positions of the No. 2 and No. 4 primary modules; Figure 4 (c) is a schematic diagram of the initial position of the No. 3 primary module;

[0026] Figure 5 It is a structural schematic diagram of an existing polygonal permanent magnet synchronous linear motor;

[0027] Figure 6 It is a structural schematic diagram of an existing polygonal permanent magnet synchronous linear motor after windings are connected;

[0028] Figure 7 It is a schematic diagram of the initial position of the primary module of the existing polygonal permanent magnet synchronous linear motor;

[0029] Figure 8 It is a comparison diagram of the no-load back-EMF waveform of the motor of the present invention and the existing motor, wherein phase A1, phase B1, and phase C1 are the three-phase windings of the motor of the present invention, and phase A2, phase B2, and phase C2 are the three-phase windings of the existing motor;

[0030] Fig. 9 It is a spectrum analysis diagram of the polygonal permanent magnet synchronous linear motor of the present invention;

[0031] Fig.10 It is the spectrum analysis diagram of the existing polygonal permanent magnet synchronous linear motor;

[0032] Fig.11 It is a comparison diagram of no-load thrust between the motor of the present invention and the existing motor;

[0033] Fig.12 It is a load thrust comparison diagram of the motor of the present invention and the existing motor;

[0034] Fig.13 It is the ABC three-phase self-inductance diagram of the motor of the present invention;

[0035] Fig.14 It is the ABC three-phase self-inductance diagram of the existing motor. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0038] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0039] Specific implementation method 1: The following is combined Figures 1 to 14 The present embodiment is described. The present embodiment describes a method for suppressing thrust fluctuation of a polygonal permanent magnet synchronous linear motor. The polygonal permanent magnet synchronous linear motor includes four primary modules and a secondary module. The four primary modules form a quadrilateral outer contour. The secondary module is arranged inside the polygonal outer contour. The air gap between each primary module and the secondary module is the same. The longitudinal section of the secondary module is a rectangle.

[0040] The method for suppressing thrust fluctuation is that the armature windings in different primary modules act on the permanent magnets of the secondary modules respectively to achieve symmetry, and the method includes:

[0041] The armature windings of the four primary modules are wound separately inside the respective modules, and then the armature windings under each phase of the four primary modules are connected in series or in parallel to form a phase winding;

[0042] The armature winding arrangement of the two primary modules corresponding to the two long sides of the secondary is any two of ABC, BCA and CAB; the armature winding arrangement of the two primary modules corresponding to the two short sides of the secondary is the same and is the remaining one;

[0043] The stacking thickness of the armature windings of the two primary modules corresponding to the two long sides of the secondary is D 1 , D 3 The stacking thickness of the armature windings of the two primary modules corresponding to the two short sides of the secondary is D 2 , D 4 ; and there is a relationship: D 1 =D 3 =2D 2 =2D 4 ;

[0044] The initial position of the primary module for the armature winding arrangement ABC is 2kτ, and the initial position of the armature winding arrangement BCA is The initial position of the armature winding arrangement is CAB. k is a positive integer, τ is the secondary permanent magnet pole pitch, and P is the number of permanent magnet pole pairs.

[0045] The four primary modules have the same axial length.

[0046] The core of the primary module is made of silicon steel sheet, amorphous alloy material or soft magnetic composite material.

[0047] The secondary module includes a secondary iron core and a permanent magnet. The secondary iron core is a rectangular frame structure with openings at both ends. The secondary iron core is made of magnetic conductive material or non-magnetic conductive material.

[0048] The magnetic conductive material of the secondary core is silicon steel sheet, amorphous alloy material or soft magnetic composite material.

[0049] The non-magnetic conductive material of the secondary core is aluminum alloy or titanium alloy.

[0050] The permanent magnets of the secondary modules are parallel magnetized, axial magnetized or Halbach magnetized.

[0051] The following is a specific example:

[0052] The polygonal permanent magnet synchronous linear motor includes four primary modules, which are primary module No. 1 1, primary module No. 2 2, primary module No. 3 3 and primary module No. 4 4 in the circumferential direction. The four primary modules can be fixed inside the housing and keep a fixed distance air gap with the secondary module. The secondary module includes a secondary iron core 6 and a permanent magnet 7. The secondary iron core 6 is a rectangular frame structure with openings at both ends. The permanent magnet 7 is arranged on each side of the secondary facing the primary. The modules are connected by mechanical and electrical connectors, and have a high degree of interchangeability and compatibility.

[0053] The design of the primary module is the focus of the present invention. The initial positions of the primary modules of the existing motors are the same, all of which are 2kτ, annular windings, and the phases of the primary modules are consistent. Therefore, there must be two phases in the three-phase winding whose back electromotive force is different from the other phase, which leads to large thrust fluctuations. In order to improve the asymmetry of the three-phase winding and reduce the thrust fluctuation of the linear motor, the phases of the primary modules of the present invention are inconsistent. The technical means used are to design the initial positions of the primary modules to be different. The armature windings in different primary modules act on the secondary permanent magnets respectively, which are symmetrical from the motor end side, and the symmetry of the three-phase winding can be improved.

[0054] The shapes of the two primary armatures of the No. 2 primary module 2 and the No. 4 primary module 4 are completely identical, the shapes of the two primary armatures of the No. 1 primary module 1 and the No. 4 primary module 4 are completely identical, and the stacking thickness of two adjacent primary armatures is 2 times.

[0055] The three-phase armature winding arrangement modes in the four primary modules include ABC, BCA, and CAB, wherein the armature winding arrangement modes of the primary module No. 1 and the primary module No. 3 are any one of the arrangements, such as ABC and CAB. Then the armature winding arrangement modes of the primary module No. 2 and the primary module No. 4 are the remaining one: BCA. That is, the armature winding arrangement modes of the two primary modules corresponding to the secondary short sides are the same, and the armature winding arrangement modes of the two primary modules corresponding to the secondary long sides are different, and are different from the armature winding arrangement modes of the two primary modules corresponding to the secondary short sides.

[0056] The stacking thickness of the armature winding of the primary module satisfies the relationship D 1 =D 3 =2D 2 =2D 4 , D 1 is the stacking thickness of the armature winding of primary module 1, D 2 is the stacking thickness of the armature winding of the second primary module 2, D 3 is the stacking thickness of the armature winding of primary module 3, D 4 is the stacking thickness of the armature winding of the fourth primary module 4.

[0057] The primary armature winding is a single-layer winding. Figure 3 ,in Figure 3 (a) is the initial position 2kτ of primary module 1, Figure 3 (b) is the initial position of primary module 2 and primary module 4 Figure 3 (c) is the initial position of primary module 3 The initial position of each primary is different. The armature windings in different primary windings act on the secondary permanent magnets respectively. Each phase winding is located at the two ends and the middle in turn, and is symmetrical from the motor end side. Similarly, the primary armature winding is a double-layer winding. Figure 4 .

[0058] Below, the performance of the motor is explained by taking a single-layer winding, three-phase 6-slot 7-pole as an example. Figure 8 A comparison diagram of the no-load back EMF waveforms of the motor of the present invention and the existing motor is given, wherein phase A1, phase B1, phase C1 are the three-phase windings of the motor of the present invention, and phase A2, phase B2, phase C2 are the three-phase windings of the existing motor; it can be seen that the no-load back EMF amplitude of phase B2 located in the middle of the primary in the existing motor is significantly lower than phase A2 and phase C2 located at both ends of the primary, while the three-phase no-load back EMF amplitudes of the motor of the present invention are almost the same, which improves the problem of unbalanced three-phase back EMF of the existing motor, and the no-load back EMF balance of the motor of the present invention is better.

[0059] Fig. 9 This is a spectrum analysis diagram of the polygonal permanent magnet synchronous linear motor of the present invention. It can be seen that the three-phase no-load back EMF fundamental wave content of the motor of the present invention is almost the same, and the high-order harmonic content is low, and the three-phase no-load back EMF balance is good.

[0060] Fig.10 It is a spectrum analysis diagram of the existing polygonal permanent magnet synchronous linear motor. The three-phase no-load back EMF fundamental wave content of the existing motor is different, and there are certain high-order harmonics in each phase, which will affect the sinusoidality and balance of the no-load back EMF, and thus cause thrust fluctuation problems.

[0061] Fig.11 This is a comparison diagram of the no-load thrust of the motor of the present invention and the existing motor. It can be seen that the thrust fluctuation of the motor of the present invention when no-load is much lower than the thrust fluctuation of the existing motor, which is beneficial to improving the problem resistance of the motor system.

[0062] Fig.12 This is a load thrust comparison diagram of the motor of the present invention and the existing motor. It can be seen that the thrust fluctuation of the motor of the present invention is much lower than that of the existing motor under load, which is beneficial to improve the problem resistance of the motor system.

[0063] Fig.13 This is the self-inductance diagram of the motor of the present invention. It can be seen that the average values ​​of the three-phase inductances are close, and the problem of unbalanced three-phase inductances is greatly improved.

[0064] Fig.14 This is the self-inductance diagram of the existing motor. It can be seen that the average values ​​of the three-phase inductances are quite different. The average value of the B-phase inductance in the middle of the primary is significantly higher than the A and C-phase inductances on both sides. The existing motor has a three-phase inductance imbalance problem.

[0065] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the present invention. It should therefore be understood that many modifications may be made to the exemplary 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 various dependent claims and features described herein may be combined in a manner different from that described in the original claims. It should also be understood that the features described in conjunction with a single embodiment may be used in other described embodiments.

Claims

1. A method for suppressing thrust fluctuation of a polygonal permanent magnet synchronous linear motor, wherein the polygonal permanent magnet synchronous linear motor comprises four primary modules and a secondary module, wherein the four primary modules form a quadrilateral outer contour, the secondary module is arranged inside the polygonal outer contour, each primary module has the same air gap as the secondary module, and the longitudinal section of the secondary module is a rectangle; It is characterized in that The thrust fluctuation suppression method is that the armature windings in different primary modules act on the permanent magnets of the secondary modules respectively to achieve symmetry, and the method includes: The armature windings of the four primary modules are wound separately inside the respective modules, and then the armature windings under each phase of the four primary modules are connected in series or in parallel to form a phase winding; The armature winding arrangement of the two primary modules corresponding to the two long sides of the secondary is any two of ABC, BCA and CAB; the armature winding arrangement of the two primary modules corresponding to the two short sides of the secondary is the same, and is the remaining one; the overlapping thickness of the armature winding of the two primary modules corresponding to the two long sides of the secondary is D1 and D3; the overlapping thickness of the armature winding of the two primary modules corresponding to the two short sides of the secondary is D2 and D4; and there is a relationship: D1=D3=2D2=2D4; the initial position of the primary module with the armature winding arrangement ABC is 2kτ, and the initial position of the armature winding arrangement BCA is The initial position of the armature winding arrangement is CAB. k is a positive integer, τ is the secondary permanent magnet pole pitch, and P is the number of permanent magnet pole pairs.

2. According to claim 1, a method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor is characterized in that: The primary armature winding is a single-layer winding or a double-layer winding.

3. According to claim 1, a method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor is characterized in that: The core of the primary module is made of silicon steel sheet, amorphous alloy material or soft magnetic composite material.

4. According to claim 2, a method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor is characterized in that: The secondary module includes a secondary iron core and a permanent magnet. The secondary iron core is a rectangular frame structure with openings at both ends. The secondary iron core is made of magnetic conductive material or non-magnetic conductive material.

5. According to claim 3, a method for suppressing thrust fluctuation of a polygonal permanent magnet synchronous linear motor is characterized in that: The magnetic conductive material of the secondary core is silicon steel sheet, amorphous alloy material or soft magnetic composite material.

6. A method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor according to claim 3, characterized in that: The non-magnetic conductive material of the secondary core is aluminum alloy or titanium alloy.

7. A method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor according to claim 3, characterized in that: The permanent magnets of the secondary modules are parallel magnetized, axial magnetized or Halbach magnetized.

8. The method for suppressing thrust fluctuation of a polygonal permanent magnet linear synchronous motor according to claim 1, characterized in that: The four primary modules have the same axial length.

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