A construction method of a bilateral suspension motor

Abstract

The present invention discloses a construction method of a bilateral suspension motor. By using the Fourier decomposition method to analyze the magnetic field pole pairs of the permanent magnet in the air gap, the suspension winding is wound to generate a stable suspension force. First, determine the permanent magnet pole pairs and the number of modulation blocks of the motor, then modify the magnetic potential of the permanent magnet into a sine wave, and use Fourier decomposition to determine the fundamental wave pole pairs and rotation speed of the permanent magnet in rotation and at rest. According to the conditions for generating the suspension force, screen out possible suspension winding winding methods. Finally, according to the proposed constraint condition (n r -p s ) = p s ±2 and the principle that two magnetic fields with a difference of one pair of poles generate suspension force pulsation to determine the optimal suspension winding winding method. The suspension winding winding method provided by the present invention can set the winding of a specific suspension winding on the outer stator under the condition of determining the stator and rotor structure of the bilateral motor, so as to reduce the pulsation of the suspension force of the motor and generate a relatively stable suspension force.

Description

Technical Field

[0001] The invention relates to the technical field of bilateral motor control, and mainly to a construction method of a bilateral suspension motor. Background Art

[0002] The double-sided motor uses two stators to distribute the winding and permanent magnets respectively, which increases the space for the permanent magnets and the armature coil, increases the electromagnetic torque and improves the thermal state of the permanent magnets. Compared with the air suspension method, magnetic suspension has the advantages of high rigidity and high bearing capacity, and can adapt to ultra-clean fields and vacuum manufacturing environments. It does not require precision machining of the air suspension support surface, thereby reducing the system manufacturing cost, and is therefore widely used. At present, there is no relatively correct and unified theory for the suspension winding winding method of the double-sided motor. Therefore, for a double-sided motor with a certain physical structure, it is necessary to find a suspension winding method to make the motor produce a relatively stable suspension force.

[0003] The patent "An Asymmetric Bilateral Long Primary Magnetic Suspension Permanent Magnet Linear Synchronous Motor" (application number: 202210156103.1) proposes a suspension winding winding method for a bilateral linear motor, in which the suspension winding is wound on the lower suspension primary side of the motor, and the difference in the normal direction between the upper propulsion primary and the lower suspension primary and the secondary structure is used as the suspension force. The wound suspension winding is used to adjust the suspension force. However, this solution is proposed on the premise of a bilateral linear motor, and it uses the structural characteristics of the linear motor itself, which is not applicable to rotating motors. Therefore, a new suspension winding winding method should be found in the rotating bilateral motor to make the motor produce a more stable suspension force.

[0004] The paper "Basic Research on Bearingless Thin-film Motors, Nanjing University of Aeronautics and Astronautics, 2009" proposed that the motor can generate controllable suspension force if the armature magnetic field and the suspension magnetic field differ by one pair of poles. However, this method is only for traditional non-modulated motors and cannot be directly applied to modulated bilateral motors. It is necessary to consider the modulation effect in bilateral motors, add new constraints, and redesign the winding method of the suspension winding. Summary of the invention

[0005] Purpose of the invention: In view of the problems existing in the above-mentioned background technology, the present invention provides a construction method of a bilateral suspension motor, adopts the method of Fourier decomposition, and selects the suspension winding method according to the conditions for generating the suspension force and the newly added constraints, thereby solving the problem that the suspension winding winding method of the linear motor cannot be applied to the rotating motor, taking into account the modulation effect of the bilateral motor, and making up for the shortcomings of the traditional non-modulation type motor suspension winding winding method in the modulation type bilateral motor.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0007] A method for constructing a bilateral suspension motor, wherein the bilateral motor adopts a partitioned stator structure, and the outer stator is 2p s slot, inner stator is 2p s pole, the middle rotor modulation block is n r Pole; the inner stator is a permanent magnet surface mounted NS radial magnetization.

[0008] First, determine the number of permanent magnet pole pairs and the number of modulation blocks. The bilateral motor of the present invention adopts a partitioned stator structure, and the outer stator is 2p s slot, inner stator is 2p s pole, the middle rotor modulation block is n r The inner stator is a permanent magnet surface mounted NS radial magnetization, so it can be known that the number of permanent magnet pole pairs is p s Pole pairs, the number of modulation block pole pairs is n r Pole pairs; then modify the magnetic potential of the permanent magnet into a sine, modify the shape of the permanent magnet into a willow-leaf eyebrow shape with narrow sides and wide middle, so that the magnetic potential of the permanent magnet is distributed sinusoidally in the magnetization direction; use the Fourier decomposition method to determine the number of fundamental wave pole pairs of the permanent magnet's rotation and stillness; finally, wind the suspension winding according to the conditions for generating the suspension force.

[0009] Furthermore, the specific steps of screening a suitable suspension winding winding method include:

[0010] Step S1, using the Fourier decomposition method, since the permanent magnet is stationary on the inner stator surface, the Fourier expression of the permanent magnet magnetic potential is:

[0011]

[0012] where θ 1 is the semi-arc angle of the permanent magnet, θ 3 is the half arc of the permanent magnet plus the stator tooth arc angle, F PM is the amplitude of the permanent magnet magnetomotive force. It can be seen that the permanent magnet itself will generate a pole pair number of (2i-1)p in the motor air gap. s The static magnetic field, where i = 1, 2, 3, ..., p s is the number of pole pairs of the permanent magnet, and the rotation speed of these magnetic fields is zero, which belongs to the stationary wave. When the shape of the permanent magnet is modified, the magnetic potential of the permanent magnet is sinusoidally distributed in the magnetization direction, and the harmonic components in the air gap will be eliminated. At this time, the air gap magnetic field is the number of pole pairs p s Magnetic field.

[0013] At this time, the number of pole pairs of the modulation block is n r , the Fourier expression of the air gap permeance of the modulation block is:

[0014]

[0015] Where Ω ris the mechanical angular velocity of the modulation block, θ 0 is the initial modulation block magnetic pole position, θ 2 is the half arc angle of the modulation block, P 0 is the DC component of the permeance, P 2 It is half of the difference between the peak and valley values ​​of the permeability waveform.

[0016] Since the air gap magnetic flux density is equal to the product of the magnetomotive force and the air gap magnetic permeance, the Fourier expression of the air gap magnetic flux density is:

[0017]

[0018] It can be seen that after the magnetic field generated by the permanent magnet is modulated by the modulation block, a pole pair number of kn will be generated in the air gap. r +(2i-1)p s and|kn r -(2i-1)p s | rotating magnetic field, where k = 1, 2, 3, ..., and the number of pole pairs is kn r +(2i-1)p s The rotation speed of the magnetic field is The number of pole pairs is |kn r -(2i-1)p s The rotation speed of the magnetic field is

[0019] Step S2: Consider the number of pole pairs of the main magnetic field, so take k = 1. Since the number of pole pairs is kn r +(2i-1)p s The number of magnetic field pole pairs is too high, and the winding is wound into kn r +(2i-1)p s When the pole pairs are used, the high-order harmonic components of the winding are used. Their amplitude is very small and their contribution to the suspension force is small. Therefore, they are not considered when analyzing the winding of the suspension winding. Therefore, only the pole pairs with the number of kn are analyzed. r -(2i-1)p s | magnetic field, it is known that the permanent magnet itself will generate a pole pair number of (2i-1)p in the motor air gap. s The static magnetic field has a pole pair number of p after the permanent magnet magnetic potential is sinusoidal. s The static magnetic field has an electrical angular velocity of zero; when k = 1, the number of magnetic field pole pairs after modulation is (n r -p s ), the rotation speed of the magnetic field is Its electrical angular velocity is Therefore, the number of pole pairs generated by the permanent magnet itself in the air gap is p. s The magnetic field has a rotation speed of zero, which belongs to the stationary wave, and its electrical angular velocity is also zero. The number of pole pairs of the permanent magnet magnetic field after modulation by the modulation block is (nr -p s ) has a magnetic field whose rotation speed is Its electrical angular velocity is

[0020] Step S3: According to the conditions for generating the levitation force, the motor can only generate a controllable levitation force when the pole pairs of the two magnetic fields in the air gap differ by one pair of poles and the electrical angular velocities of the two magnetic fields are the same. As can be seen from step S2, the pole pair number of the rotating magnetic field in the air gap is (n r -p s ), so the suspension winding can be wound into (n r -p s -1) opposite pole or (n r -p s +1) Opposite.

[0021] Step S4: For the traditional non-modulation motor, the armature winding and the suspension winding differ by one pair of poles, and the motor can generate a controllable stable suspension force. The bilateral motor of the present invention belongs to the modulation motor, and there is a modulation effect in the motor, so the constraint condition is proposed: (n r -p s )=p s ±2.

[0022] When the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) satisfies(n r -p s )=p s -2, the first winding method is to wind the suspension winding into (n r -p s +1) pole pairs, then the winding will produce a pole pair number (n r -p s +1) has a magnetic field harmonic whose rotation speed is Its electrical angular velocity is The (n r -p s +1) subharmonic will generate pole pairs n in the air gap after being modulated by the modulation block r -(n r -p s +1)=p s -1 magnetic field, the rotation speed of the magnetic field is zero, which belongs to the stationary wave, and its electrical angular velocity is also zero; at this time, the number of pole pairs generated by the permanent magnet itself is p s The magnetic field and the suspension winding are modulated by the modulation block to produce a pole pair number of p s The magnetic field of -1 just satisfies the difference of pole pairs by one, and the electric angular velocity is the same and is zero, which can generate a stable suspension force. In addition, the pole pairs generated by the permanent magnet after modulation by the modulation block are (n r-p s ) and the pole pairs generated by the suspension winding itself are (n r -p s +1) has a pole pair number that is one different, and the electrical angular velocity is the same, both n. r Ω r , a stable suspension force can be generated, but at this time the number of pole pairs generated by the permanent magnet itself is p s The number of pole pairs generated by the magnetic field and the suspension winding itself is (n r -p s +1) satisfies the difference in pole pairs, but the electric angular velocities of the two magnetic fields are different. The electric angular velocity of the former is zero, and the electric angular velocity of the latter is n r Ω r , the two magnetic fields will produce suspension force pulsation. In summary, in this case, when the suspension winding is wound into (n r -p s +1) when the poles are aligned, the motor will produce a suspension force with large pulsation and cannot produce a relatively stable suspension force. The second winding method is to wind the suspension winding into (n r -p s -1) pole pairs, at this time the winding will produce a pole pair number (n r -p s -1) has a magnetic field harmonic whose rotation speed is Its electrical angular velocity is The (n r -p s -1) After the subharmonic is modulated by the modulation block, a pole pair number of n will be generated in the air gap r -(n r -p s -1)=p s +1 magnetic field, the rotation speed of the magnetic field is zero, which belongs to the stationary wave, and its electrical angular velocity is also zero; at this time, the number of pole pairs generated by the permanent magnet itself is p s The magnetic field and the suspension winding are modulated by the modulation block to produce a pole pair number of p s +1 magnetic field just satisfies the difference of pole pairs and the same electrical angular velocity is zero, which can generate a stable suspension force. In addition, the pole pairs generated by the permanent magnet after modulation by the modulation block are (n r -p s ) and the pole pairs generated by the suspension winding itself are (n r -p s -1) has a pole pair number that is one different, and the electrical angular velocity is the same, both n. r Ω r , can generate a stable suspension force. In summary, when the suspension winding is wound into (n r -p s-1) pole pairs, the motor will produce a relatively stable suspension force. When the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) satisfies(n r -p s )=p s +2, the suspension winding is wound into (n r -p s +1) pairs of poles produce a relatively stable suspension force. When the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) does not satisfy (n r -p s )=p s ±2, the suspension winding is wound into (n r -p s -1) opposite pole or (n r -p s +1) Both poles can generate relatively stable suspension force, and the analysis method is as above.

[0023] Beneficial effects:

[0024] The present invention provides a method for constructing a bilateral suspension motor, which uses a Fourier decomposition method to select a suspension winding winding method according to newly added constraints and the conditions for generating suspension forces. The suspension winding winding method proposed by the present invention solves the problem that the suspension winding winding method of a linear motor cannot be applied to a rotating motor, takes into account the modulation effect of the bilateral motor, and makes up for the deficiency of the traditional non-modulation type motor suspension winding winding method in the modulation type bilateral motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a general structural diagram of a bilateral motor provided in an embodiment of the present invention;

[0026] Figure 2 is a structural diagram of a bilateral motor rotor modulation block provided in an embodiment of the present invention;

[0027] Figure 3 It is a schematic diagram of the suspension winding method of the bilateral motor provided by the present invention;

[0028] Figure 4 It is a diagram of winding three pairs of poles of a suspension winding in an embodiment of the present invention;

[0029] Figure 5 It is a suspension force diagram of a motor with three pairs of poles having a suspension winding according to an embodiment of the present invention;

[0030] Figure 6 It is a diagram of the winding of 5 pairs of poles of the suspension winding in the embodiment of the present invention;

[0031] Figure 7It is a suspension force diagram of a motor with 5 pairs of poles having a suspension winding according to an embodiment of the present invention;

[0032] In the figure: 1. Suspension winding; 2. Intermediate rotor; 3. External stator; 4. Permanent magnets attached to the surface of the internal stator; 5. Internal stator; 6. Magnetic blocks. DETAILED DESCRIPTION

[0033] The present invention is further described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, rather than all 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.

[0034] The present invention provides a method for constructing a bilateral suspension motor using a bilateral motor structure. The specific implementation adopts a commonly used bilateral motor structure. The bilateral motor is a partitioned stator, the outer stator is 12 slots, the inner stator is 12 poles, and the intermediate rotor modulation block is 10 poles; the inner stator is a permanent magnet surface-mounted NS radial magnetization. Therefore, in this specific bilateral motor, the inner stator pole pair number p s =6, rotor modulation block pole number n r = 10. The overall structure of the double-sided motor is shown in Figure 1. The arrow indicates the magnetization direction of the inner stator permanent magnet. The shape of the permanent magnet can be modified. The rotor modulation block structure is shown in Figure 1. Figure 2 shown.

[0035] The magnetic potential of the permanent magnet is modified to be sinusoidal, and the shape of the permanent magnet is modified to be willow-shaped with narrow sides and wide in the middle, so that the magnetic potential of the permanent magnet is distributed sinusoidally in the magnetization direction. Next, the Fourier decomposition method is used to determine the fundamental wave pole pairs of the permanent magnet in rotation and stillness; finally, the suspension winding is wound according to the conditions for the generation of suspension force, as shown in Figure 3.

[0036] Step S1: Using Fourier decomposition method, since the permanent magnet is stationary on the inner stator surface,

[0037]

[0038] The permanent magnet itself will generate a stationary magnetic field with a pole pair number of (2i-1)*6 in the air gap of the motor, where i=1,2,3,..., and the rotation speed of these magnetic fields is zero, which belongs to a stationary wave. When the shape of the permanent magnet is modified, the magnetic potential of the permanent magnet is sinusoidally distributed in the magnetization direction, and the harmonic components in the air gap will be eliminated. At this time, the air gap magnetic field is a magnetic field with a pole pair number of 6.

[0039] At this time, the number of pole pairs of the modulation block is 10, and the Fourier expression of the air gap permeance of the modulation block is:

[0040]

[0041] Since the air gap magnetic flux density is equal to the product of the magnetomotive force and the air gap magnetic permeance, the Fourier expression of the air gap magnetic flux density is:

[0042]

[0043] It can be seen that after the magnetic field generated by the permanent magnet is modulated by the modulation block, a rotating magnetic field with pole pairs of k*10+(2i-1)*6 and |k*10-(2i-1)*6| will be generated in the air gap, where k=1,2,3,..., and the rotation speed of the magnetic field with a pole pair number of k*10+(2i-1)*6 is The rotation speed of the magnetic field with a pole pair number of |k*10-(2i-1)*6| is

[0044] Step S2, considering the number of pole pairs of the main magnetic field, k=1 is taken. Since the number of pole pairs of the magnetic field with 16 pole pairs is too high, when the winding is wound into 16 pole pairs, the high-order harmonic components of the winding are used, and their amplitude is very small and their contribution to the suspension force is small. Therefore, they are not considered when analyzing the winding of the suspension winding. Therefore, only the magnetic field with a pole pair number of 4 is analyzed. It is known that the permanent magnet itself will generate a static magnetic field with a pole pair number of (2i-1)*6 in the air gap of the motor. After the magnetic potential of the permanent magnet is sinusoidal, the magnetic field has only a static magnetic field with a pole pair number of 6, and its electrical angular velocity is zero; when k=1, the number of magnetic field pole pairs after modulation is 4, and the rotation speed of the magnetic field is Its electrical angular velocity is Therefore, at this time, there is a magnetic field with a pole pair number of 6 generated by the permanent magnet itself in the air gap. The rotation speed of this magnetic field is zero and it belongs to a stationary wave. Its electrical angular velocity is zero. There is also a magnetic field with a pole pair number of 4 after the permanent magnet magnetic field is modulated by the modulation block. The rotation speed of this magnetic field is Its electrical angular velocity is

[0045] Step S3: According to the conditions for generating the suspension force, the motor can generate a controllable suspension force only when the pole pairs of the two magnetic fields in the air gap differ by one pole pair and the electrical angular velocities of the two magnetic fields are the same. As can be seen from step S2, the pole pair number of the rotating magnetic field in the air gap is 4 at this time, so the suspension winding can be wound into 3 pole pairs or 5 pole pairs.

[0046] Step S4, considering the proposed constraints, when the number of pole pairs of the rotating magnetic field in the air gap is 4 and satisfies 4=6-2, the first winding method is to wind the suspension winding into 5 pairs of poles. At this time, the winding will generate a magnetic field harmonic with a pole pair number of 5 in the air gap, and the rotation speed of the magnetic field is Its electrical angular velocity is After the 5th harmonic is modulated by the modulation block, a magnetic field with a pole pair number of 10-5=5 will be generated in the air gap. The rotation speed of the magnetic field is zero and it belongs to a stationary wave, and its electrical angular velocity is zero. At this time, the magnetic field with a pole pair number of 6 generated by the permanent magnet itself and the magnetic field with a pole pair number of 5 generated by the suspension winding after modulation by the modulation block just meet the difference of the pole pair number by one, and the electrical angular velocity is the same as zero, which can generate a stable suspension force. In addition, the magnetic field with a pole pair number of 4 generated by the permanent magnet after modulation by the modulation block and the magnetic field with a pole pair number of 7 generated by the suspension winding itself just meet the difference of the pole pair number by one, and the electrical angular velocity is the same as 10Ω. r , a stable suspension force can be generated. However, the magnetic field with a pole pair number of 6 generated by the permanent magnet itself and the magnetic field with a pole pair number of 5 generated by the suspension winding itself satisfy the difference of pole pair number of one, but the electrical angular velocity of the two magnetic fields is different. The electrical angular velocity of the former is zero, and the electrical angular velocity of the latter is 10Ω. r The two magnetic fields will generate suspension force pulsation, and the suspension winding is wound with 5 pairs of poles. Figure 4 As shown in Figure 2, the suspension force of the motor is as follows: Figure 5 As shown, it can be seen that the motor suspension force pulsates greatly at this time, and the motor cannot generate a stable suspension force. In summary, in this case, when the suspension winding is wound into 5 pairs of poles, the motor will generate a suspension force with a large suspension force pulsation and cannot generate a relatively stable suspension force. The second winding method is to wind the suspension winding into 3 pairs of poles. At this time, the winding will generate a magnetic field harmonic with a pole pair number of 3 in the air gap. The rotation speed of this magnetic field is Its electrical angular velocity is After the third harmonic is modulated by the modulation block, a magnetic field with a pole pair number of 10-3=7 will be generated in the air gap. The rotation speed of the magnetic field is zero and it belongs to a stationary wave, and its electrical angular velocity is zero. At this time, the magnetic field with a pole pair number of 6 generated by the permanent magnet itself and the magnetic field with a pole pair number of 7 generated by the suspension winding after modulation by the modulation block just meet the difference of the pole pair number by one, and the electrical angular velocity is the same as zero, which can generate a stable suspension force. In addition, the magnetic field with a pole pair number of 4 generated by the permanent magnet after modulation by the modulation block and the magnetic field with a pole pair number of 3 generated by the suspension winding itself just meet the difference of the pole pair number by one, and the electrical angular velocity is the same as 10Ω. r , can generate a stable suspension force. In summary, when the suspension winding is wound into three pairs of poles, the motor will generate a relatively stable suspension force. Figure 6 As shown in Figure 2, the suspension force of the motor is as follows: Figure 7 As shown, it can be seen that the pulsation of the motor suspension force is small at this time, and the motor produces a stable suspension force.

[0047] In summary, if the constraints proposed by the present invention are not considered, the suspension winding wound with 5 pairs of poles according to the traditional design of the suspension motor cannot achieve stable suspension. The winding designed with the constraints proposed by the present invention can achieve stable suspension of the bilateral motor.

[0048] The above is only a preferred embodiment of the present invention. This scheme can also be used to design the suspended winding for other bilateral motors with tooth slots. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for constructing a bilateral suspension motor, characterized in that: Determine the number of permanent magnet pole pairs and the number of modulation blocks, and modify the magnetic potential of the permanent magnet to be sinusoidal; use Fourier decomposition method to determine the number of rotational and stationary fundamental wave pole pairs of the permanent magnet; wind the suspension winding according to the conditions for generating the suspension force, and set constraints to optimally wind the suspension winding to reduce the suspension force pulsation under multi-harmonic operation; The Fourier decomposition method is used to determine the number of fundamental wave pole pairs of the permanent magnet in rotation and at rest. The specific steps include: Perform Fourier decomposition on the sinusoidal permanent magnet magnetic potential to determine the number of pole pairs generated by the permanent magnet in the motor air gap as p s The static magnetic field of the permanent magnet is generated by a magnetic field with a pole pair number of n. r After modulation by the modulation block, the number of pole pairs generated in the air gap is kn r +(2i-1)p s and|kn r -(2i-1)p s | a rotating magnetic field, where k = 1, 2, 3, ..., i = 1, 2, 3, ..., the number of pole pairs is kn r +(2i-1)p s The rotation speed of the magnetic field is The number of pole pairs is |kn r -(2i-1)p s The rotation speed of the magnetic field is Ω r is the mechanical angular velocity of the rotor modulation block; The specific steps of winding the suspension winding according to the conditions for generating the suspension force include: Take k = 1, the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ), so the suspension winding is wound into (n r -p s -1) opposite pole or (n r -p s +1) Antipodes; The constraint condition for the number of pole pairs of the rotating magnetic field in the air gap is: (n r -p s )=p s ±2; When the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) satisfies(n r -p s )=p s -2, the suspension winding is wound into (n r -p s -1) pairs of poles; when the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) satisfies(n r -p s )=p s +2, the suspension winding is wound into (n r -p s +1) pairs of poles; when the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s ) does not satisfy (n r -p s )=p s ±2, the suspension winding is wound into (n r -p s -1) opposite pole or (n r -p s +1).

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