General construction method of bearingless magnetic gear double-sided motor with fundamental and harmonic global cancellation

Abstract

This invention discloses a general construction method for a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation. The method consists of three levels: preliminary optimization, constraint 1 for the cancellation of armature magnetic field harmonics and permanent magnet harmonics before modulation, and constraint 2 for the cancellation of armature magnetic field harmonics and permanent magnet harmonics after modulation. Preliminary optimization can only reduce the pulsation generated by the fundamental wave of the levitation magnetic field and the stationary wave of the permanent magnet. Based on this, constraint 1 is proposed to reduce the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics before modulation, and constraint 2 is proposed to reduce the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics after modulation. Through the principle of global fundamental harmonic cancellation, this invention effectively reduces the levitation force pulsation of the bearingless magnetic gear double-sided motor, overcoming the shortcomings of traditional and existing levitation motor construction methods.

Description

Technical Field

[0001] This invention relates to the field of bilateral motor control technology, and mainly to a general construction method for a bearingless magnetic gear bilateral motor with global cancellation of fundamental harmonics. Background Technology

[0002] Double-sided motors employ two stators, each with its own windings and permanent magnets. This increases the space available for the permanent magnets and armature coils, improving electromagnetic torque and thermal stability. Compared to air suspension, magnetic levitation offers advantages such as higher stiffness and load-bearing capacity. It can also be used in ultra-clean environments and vacuum manufacturing, eliminating the need for precision machining of the air-bearing support surface and thus reducing system manufacturing costs. Therefore, it is widely adopted. Currently, there is no universally accepted theory on the winding method for the suspension windings of double-sided motors. Therefore, for a double-sided motor with a defined physical structure, it is necessary to find a winding method for the suspension windings to generate a more stable levitation force.

[0003] The doctoral dissertation, "Fundamental Research on Bearingless Thin-Layer Motors (Nanjing University of Aeronautics and Astronautics, 2009)," proposed that a motor can generate controllable levitation force when the armature magnetic field and the levitation magnetic field differ by a pair of poles. However, this method is designed for traditional non-modulated motors and cannot be directly applied to modulated double-sided motors. It is necessary to consider the modulation effect in double-sided motors, add new constraints, and redesign the winding method of the levitation winding.

[0004] The construction method proposed in the document "A Construction Method for a Double-Sided Suspension Motor (Application No. 202210891366.7)" can eliminate the suspension force pulsation generated by the fundamental wave of the suspension magnetic field and the stationary wave of the permanent magnet. However, it does not consider the suspension force pulsation generated by the armature magnetic field harmonics and the various harmonics of the permanent magnet before and after modulation. The bearingless magnetic gear double-sided motor constructed according to the construction method proposed in the document "A Construction Method for a Double-Sided Suspension Motor (Application No. 202210891366.7)" still has a large suspension force pulsation. Summary of the Invention

[0005] Purpose of the invention: To address the problems existing in the background technology, this invention provides a general construction method for a bearingless magnetic gear double-sided motor with global cancellation of fundamental harmonics. Under the premise that existing technology can only eliminate the levitation force pulsation generated by the fundamental wave of the levitation magnetic field and the stationary wave of the permanent magnet, this invention proposes cancellation constraints (constraint 1) for the armature magnetic field harmonics before modulation and the harmonics of the permanent magnet after modulation and the harmonics of the permanent magnet after modulation (constraint 2), thus completely solving the problem of large levitation force pulsation in the bearingless magnetic gear double-sided motor.

[0006] Technical solution: To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0007] A general construction method for a bearingless dual-sided geared motor with global fundamental harmonic cancellation is presented, comprising three levels: preliminary optimization, cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics before modulation (constraint 1), and cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics after modulation (constraint 2). The preliminary optimization steps are as follows:

[0008] The aforementioned dual-sided motor adopts a partitioned stator structure, with the outer stator being 2p. s The slot has an inner stator of 2p. s The pole, the intermediate rotor modulation block is n r The inner stator is a permanent magnet surface-mounted NS radial magnet.

[0009] First, determine the number of permanent magnet pole pairs and the number of modulation blocks. The dual-sided motor described in this invention adopts a partitioned stator structure, with the outer stator being 2p. s The slot has an inner stator of 2p. s The pole, the intermediate rotor modulation block is n r The inner stator is a surface-mounted NS radial magnet with permanent magnets, therefore the number of pole pairs of the permanent magnet is p. s For each pole, the number of modulation block pole pairs is n r First, the magnetomotive force of the permanent magnet is adjusted to a sinusoidal shape, and its shape is modified to a willow leaf shape, narrow on both sides and wide in the middle, so that the magnetomotive force of the permanent magnet is distributed sinusoidally in the magnetization direction. The Fourier decomposition method is used to determine the number of fundamental pole pairs of the permanent magnet in rotation and at rest. Finally, the suspension winding is wound according to the conditions for the generation of suspension force.

[0010] Furthermore, the specific steps for selecting a suitable levitation winding method include:

[0011] Step S1: Using the Fourier decomposition method, since the permanent magnet is stationary on the inner stator surface, the Fourier expression for the magnetomotive force of the permanent magnet is:

[0012]

[0013] Where θ1 is the half-arc angle of the permanent magnet, θ3 is the half-arc angle of the permanent magnet plus the stator tooth arc angle, F PM This is the magnetomotive force amplitude of the permanent magnet. 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 A stationary magnetic field, where i = 1, 2, 3, ..., p s Let p be the number of pole pairs of the permanent magnet, and let p be the number of pole pairs of the magnetic field. Since the rotational speed of these magnetic fields is zero, they belong to stationary waves. When the shape of the permanent magnet is modified, the magnetomotive force of the permanent magnet is sinusoidally distributed in the magnetization direction, and the harmonic components in the air gap are eliminated. At this time, the air gap magnetic field has a pole pair number of p. s Magnetic field.

[0014] At this point, the number of pole pairs of the modulation block is n. rThe Fourier expression for the air gap permeability of the modulation block is:

[0015]

[0016] Where Ω r θ0 is the mechanical angular velocity of the modulator block, θ2 is the initial magnetic pole position of the modulator block, θ2 is the half-arc angle of the modulator block, P0 is the DC component of the magnetic permeability, and P2 is half the difference between the peak and valley values ​​of the magnetic permeability waveform.

[0017] Since the air gap magnetic flux density is equal to the product of the magnetomotive force and the air gap permeability, the Fourier expression for the air gap magnetic flux density is:

[0018]

[0019] It can be seen that the magnetic field generated by the permanent magnet, after being modulated by the modulator, will produce a pole pair number of kn in the air gap. r +(2i-1)p s and |kn r -(2i-1)p s A rotating magnetic field, where k = 1, 2, 3, ..., and the number of pole pairs is kn. r +(2i-1)p s The rotational speed of the magnetic field is The pole logarithm is |kn r -(2i-1)p s The rotational speed of the magnetic field is

[0020] Step S2: Considering the number of main magnetic field pole pairs, we take k = 1. Since the number of pole pairs is kn r +(2i-1)p s The magnetic field pole pair number is too high, and the winding is wound into kn r +(2i-1)p s The high-order harmonic components of the winding are utilized in the pole pair analysis. Since their amplitude is very small and contributes little to the levitation force, they are not considered when analyzing the levitation winding. Therefore, only the pole pair number |kn| is analyzed. r -(2i-1)p s The magnetic field of | is known from the previous discussion that the permanent magnet itself will generate a pole pair number of (2i-1)p in the air gap of the motor. s A stationary magnetic field, which has only a pole pair number of p after the magnetomotive force of the permanent magnet becomes sinusoidal. s The stationary magnetic field has an electric angular velocity of zero; when k = 1, the number of pole pairs of the modulated magnetic field is (n r -p s The rotational speed of this magnetic field is... Its electric angular velocity is Therefore, the number of pole pairs generated by the permanent magnet itself in the air gap at this time is p. sThe magnetic field has a zero rotational speed and is a stationary wave; its electric angular velocity is also zero. Furthermore, the permanent magnet's magnetic field, after being modulated by the modulation block, has a pole pair number (n...). r -p s The magnetic field has a rotational speed of . Its electric angular velocity is

[0021] Step S3: According to the conditions for the generation of levitation force, a controllable levitation force can only be generated in the motor when the number of pole pairs of the two magnetic fields in the air gap differs by one pole pair and the electric angular velocities of the two magnetic fields are the same. From step S2, it can be seen that the number of pole pairs of the rotating magnetic field in the air gap at this time is (n... r -p s Therefore, the levitation winding can be wound into (n) r -p s -1) polar or (n) r -p s +1) opposite pole.

[0022] Step S4: For traditional non-modulated motors, the armature winding and the suspension winding differ by one pole, and the motor can generate a controllable and stable suspension force. The double-sided motor of this invention belongs to the modulated motor category, and a modulation effect exists in the motor. Therefore, the following constraint condition is proposed: (n r -p s ) = p s ±2.

[0023] 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 At -2, the first winding method is to wind a floating winding into (n) r -p s +1) For pole pairing, the winding will generate a pole pair number of (n) in the air gap. r -p s The magnetic field harmonics are +1), and the rotational speed of the magnetic field is... Its electric angular velocity is The (n) r -p s +1) After being modulated by the modulator block, the subharmonic will generate a pole pair number of n in the air gap. r -(n r -p s +1)=p s A magnetic field with a rotational velocity of -1 is a stationary wave, and its electric angular velocity is also zero; at this time, the permanent magnet itself produces p pole pairs. s The magnetic field and the number of pole pairs generated by the modulation of the levitation winding by the modulation block are p sA magnetic field of -1 satisfies the condition that the number of pole pairs differs by one, and the electric angular velocities are both zero, thus generating a stable levitation force. Furthermore, the permanent magnet, modulated by the modulation block, produces a pole pair count of (n...). r -p s The magnetic field and the number of pole pairs generated by the levitation winding itself are (n r -p s The magnetic field of +1) satisfies the condition that the number of pole pairs differs by one, and the electric angular velocities are the same, both being n. r Ω r This can generate a stable levitation force, but at this time the permanent magnet itself produces p pole pairs. s The number of pole pairs generated by the magnetic field and the levitation winding itself is (n r -p s The magnetic fields with +1 satisfy the condition that the number of pole pairs differs by one, 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 generate levitation force pulsations. In summary, under this condition, when the levitation winding is wound into (n r -p s +1) When the poles are aligned, the motor will generate a large pulsating levitation force, and cannot produce a stable levitation force. The second winding method is to wind the levitation winding into (n r -p s -1) For pole pairing, the winding will generate a pole pair number (n) in the air gap. r -p s -1) magnetic field harmonics, the rotational speed of which is Its electric angular velocity is The (n) r -p s -1) After being modulated by the modulator block, the subharmonic will generate a pole pair number of n in the air gap. r -(n r -p s -1)=p s A magnetic field with a value of +1 has a rotational velocity of zero, making it a stationary wave, and its electric angular velocity is also zero; at this time, the permanent magnet itself produces p pole pairs. s The magnetic field and the number of pole pairs generated by the modulation of the levitation winding by the modulation block are p s A magnetic field with a value of +1 satisfies the condition that the number of pole pairs differs by one, and that the electric angular velocities are both zero, thus generating a stable levitation force. Furthermore, the permanent magnet, modulated by the modulation block, produces a pole pair count of (n...). r -p s The magnetic field and the number of pole pairs generated by the levitation winding itself are (n r -p s The magnetic field of -1) satisfies the condition that the number of pole pairs differs by one, and the electric angular velocities are the same, both being n. r Ω rThis can generate a stable levitation force. In summary, when the levitation winding is wound into (n r -p s -1) When the poles are aligned, the motor will generate a relatively stable levitation 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 At +2, the levitation winding is wound into (n r -p s +1) A relatively stable levitation force is generated at the poles. When the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s (n) does not satisfy r -p s ) = p s When ±2, the suspension winding is wound into (n r -p s -1) polar or (n) r -p s +1) Both poles can generate relatively stable levitation force, and the analysis method is as above.

[0024] Furthermore, regarding P determined in the above steps... s n r Cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics before modulation with the number of pole pairs of the levitation magnetic field:

[0025] If the number of suspending pole pairs obtained by the above optimization is |n r -P s If |+1, then |n r -P s |+1 needs to satisfy the following constraints:

[0026] (1)|n r -P s +1 ≠ P s ±1 and |n r -P s +1 ≠ 2n r +P s ±1 and |n r -P s +1 ≠ 3n r +P s ±1 and |n r -P s +1 ≠ |2n r -P s |±1 and|n r -P s +1 ≠ |3n r -P s |±1;

[0027] (2)5(|n r -P s |+1)≠P s ±1 and 5(|n) r -P s |+1)≠2n r +P s ±1 and 5(|n) r -P s |+1)≠3n r +P s ±1 and 5(|n) r -P s |+1)≠|2n r -P s |±1 and 5(|n) r -P s |+1)≠|3n r -P s |±1;

[0028] (3)7(|n r -P s |+1)≠P s ±1 and 7(|n) r -P s |+1)≠2n r +P s ±1 and 7(|n) r -P s |+1)≠3n r +P s ±1 and 7(|n) r -P s |+1)≠|2n r -P s |±1 and 7(|n) r -P s |+1)≠|3n r -P s |±1 and

[0029] 7(|n r -P s +1)≠n r +P s ±1 and 7(|n) r -P s |+1)≠|n r -P s |±1;

[0030] If the number of suspending pole pairs obtained by the above optimization is |n r -P s If |—1, then |n r -P s|—1 needs to satisfy the following constraints:

[0031] (1)|n r -P s |—1≠P s ±1 and |n r -P s |—1≠2n r +P s ±1 and |n r -P s |—1≠3n r +P s ±1 and |n r -P s |—1≠|2n r -P s |±1 and|n r -P s |—1≠|3n r -P s |±1;

[0032] (2)5(|n r -P s |—1)≠P s ±1 and 5(|n) r -P s |—1)≠2n r +P s ±1 and 5(|n) r -P s |—1)≠3n r +P s ±1 and 5(|n) r -P s |—1)≠|2n r -P s |±1 and 5(|n) r -P s |—1)≠|3n r -P s |±1;

[0033] (3)7(|n r -P s |—1)≠P s ±1 and 7(|n) r -P s |—1)≠2n r +P s ±1 and 7(|n) r -P s |-1)≠3n r +P s ±1 and 7(|n) r -P s |-1)≠|2nr -P s |±1 and 7(|n) r -P s |-1)≠|3n r -P s |±1 and 7(|n) r -P s |—1)≠n r +P s ±1 and 7(|n) r -P s |—1)≠|n r -P s |±1;

[0034] Furthermore, regarding P determined in the above steps... s n r The cancellation constraint between the armature magnetic field harmonics modulated by the number of pole pairs of the levitation magnetic field and the harmonics of the permanent magnet:

[0035] If the number of suspended pole pairs obtained by the above optimization steps is |n r -P s If |+1, then |n r -P s |+1 needs to satisfy the following constraints:

[0036] (1)|n r -P s |+1+n r ≠P s ±1 and |n r -P s |+1+n r ≠n r +P s ±1 and |n r -P s |+1+n r ≠3n r +P s ±1 and |n r -P s |+1+n r ≠|n r -P s |±1 and|n r -P s |+1+n r ≠|3n r -P s |±1;

[0037] (2)||n r -P s |+1-n r |≠n r +P s±1 and ||n r -P s |+1-n r |≠2n r +P s ±1 and ||n r -P s |+1-n r |≠3n r +P s ±1 and ||n r -P s |+1-n r |≠|2n r -P s |±1 and||n r -P s |+1-n r |≠|3n r -P s |±1 and||n r -P s |+1-n r |≠|n r -P s |±1;

[0038] (3)|n r -P s |*5+5+n r ≠P s ±1 and |n r -P s |*5+5+n r ≠n r +P s ±1 and |n r -P s |*5+5≠3n r +P s ±1 and |n r -P s |*5+5+n r ≠|n r -P s |±1 and|n r -P s |*5+5+n r ≠|3n r -P s |±1;

[0039] (4)||n r -P s |*5+5-n r |≠n r +P s ±1 and ||n r -P s |*5+5-nr |≠2n r +P s ±1 and ||n r -P s |*5+5-n r |≠3n r +P s ±1 and ||n r -P s |*5+5-n r |≠|2n r -P s |±1 and||n r -P s |*5+5-n r |≠|3n r -P s |±1 and||n r -P s |*5+5-n r |≠|n r -P s |±1;

[0040] (5)|n r -P s |*7+7+n r ≠2n r +P s ±1 and |n r -P s |*7+7+n r ≠n r +P s ±1 and |n r -P s |*7+7≠3n r +P s ±1 and |n r -P s |*7+7+n r ≠|n r -P s |±1 and|n r -P s |*7+7+n r ≠|3n r -P s |±1 and|n r -P s |*7+7+n r ≠|2n r -P s |±1;

[0041] (6)||n r -P s |*7+7-n r |≠nr +P s ±1 and ||n r -P s |*7+7-n r |≠2n r +P s ±1 and ||n r -P s |*7+7-n r |≠3n r +P s ±1 and ||n r -P s |*7+7-n r |≠|2n r -P s |±1 and||n r -P s |*7+7-n r |≠|3n r -P s |±1 and||n r -P s |*7+7-n r |≠|n r -P s |±1 and||n r -P s |*7+7-n r |≠P s ±1;

[0042] If the number of suspended pole pairs obtained from step 2) is |n r -P s If |-1, then |n r -P s |-1 needs to satisfy the following constraint:

[0043] (1)|n r -P s |-1+n r ≠P s ±1 and |n r -P s |-1+n r ≠n r +P s ±1 and |n r -P s |-1+n r ≠3n r +P s ±1 and |n r -P s |-1+n r ≠|n r -P s |±1 and|nr -P s |-1+n r ≠|3n r -P s |±1;

[0044] (2)||n r -P s |-1-n r |≠n r +P s ±1 and ||n r -P s |-1-n r |≠2n r +P s ±1 and ||n r -P s |-1-n r |≠3n r +P s ±1 and ||n r -P s |-1-n r |≠|2n r -P s |±1 and||n r -P s |-1-n r |≠|3n r -P s |±1 and||n r -P s |-1-n r |≠|n r -P s |±1

[0045] (3)|n r -Ps|*5-5+n r ≠P s ±1 and |n r -P s |*5-5+n r ≠n r +P s ±1 and |n r -P s |*5-5≠3n r +P s ±1 and |n r -P s |*5-5+n r ≠|n r -P s |±1 and|n r -P s |*5-5+n r ≠|3nr -P s |±1;

[0046] (4)||n r -P s |*5-5-n r |≠n r +P s ±1 and ||n r -P s |*5-5-n r |≠2n r +P s ±1 and ||n r -P s |*5-5-n r |≠3n r +P s ±1 and ||n r -P s |*5-5-n r |≠|2n r -P s |±1 and||n r -P s |*5-5-n r |≠|3n r -P s |±1 and||n r -P s |*5-5-n r |≠|n r -P s |±1;

[0047] (5)|n r -P s |*7-7+n r ≠2n r +P s ±1 and |n r -P s |*7-7+n r ≠n r +P s ±1 and |n r -P s |*7-7≠3n r +P s ±1 and |n r -P s |*7-7+n r ≠|n r -P s |±1 and|n r -P s |*7-7+n r ≠|3n r -Ps |±1 and|n r -P s |*7-7+n r ≠|2n r -P s |±1;

[0048] (6)||n r -P s |*7-7-n r |≠n r +P s ±1 and ||n r -P s |*7-7-n r |≠2n r +P s ±1 and ||n r -P s |*7-7-n r |≠3n r +P s ±1 and ||n r -P s |*7-7-n r |≠|2n r -P s |±1 and||n r -P s |*7-7-n r |≠|3n r -P s |±1 and||n r -P s |*7-7-n r |≠|n r -P s |±1 and||n r -P s |*7-7-n r |≠P s ±1.

[0049] Finally, the number of floating pole pairs was determined to be W, and the number of external stator slots was designed to be 2*3*W, so that the floating winding is 3-phase and the winding form is an integer number of slots.

[0050] Beneficial Effects: This invention provides a construction method for a bilateral levitation motor, which is divided into three levels: preliminary optimization, cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics before modulation (constraint 1), and cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics after modulation (constraint 2). Based on the preliminary optimization which reduces the levitation force pulsation generated by the levitation magnetic field and the stationary magnetic field of the permanent magnet, a global fundamental harmonic cancellation principle is proposed, reducing the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics before modulation, and the levitation force pulsation generated by the armature magnetic field harmonics and permanent magnet harmonics after modulation. Attached Figure Description

[0051] Figure 1 This is the overall structural diagram of the dual-sided motor provided in document 202210891366.7;

[0052] Figure 2 This is a structural diagram of the dual-sided motor rotor modulation block in document 202210891366.7;

[0053] Figure 3 It is a schematic diagram of the suspension winding method for a double-sided motor provided in document 202210891366.7;

[0054] Figure 4 This is the diagram of the 3-pole suspension winding in document 202210891366.7;

[0055] Figure 5 It is the levitation force diagram of the 3-pole motor with levitation winding in document 202210891366.7 (considering the harmonics of the levitation magnetic field);

[0056] Figure 6 This is the diagram of the 5-pole suspension winding in document 202210891366.7;

[0057] Figure 7 It is the levitation force diagram of the 5-pole motor with levitation winding in document 202210891366.7 (considering the harmonics of the levitation magnetic field);

[0058] In the diagram: 1. Suspension winding; 2. Intermediate rotor; 3. Outer stator; 4. Surface-mounted permanent magnet of inner stator; 5. Inner stator; 6. Magnetic block.

[0059] Figure 8 This is a flowchart of the general construction method for a bearingless magnetic gear double-sided motor with global cancellation of fundamental harmonics, as provided in this paper.

[0060] Figure 9 This is a motor structure topology diagram constructed using the general construction method for bearingless magnetic gear double-sided motors with global cancellation of fundamental harmonics provided by this method.

[0061] Figure 10The levitation force of the motor is constructed using the universal construction method of bearingless magnetic gear double-sided motor with global cancellation of fundamental harmonics provided by this method. Detailed Implementation

[0062] The present invention will be further described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0063] This invention provides a method for constructing a double-sided levitation motor, employing a double-sided motor structure. Specifically, it utilizes a commonly used double-sided motor structure with a partitioned stator: the outer stator has 12 slots, the inner stator has 12 poles, and the intermediate rotor modulation block has 10 poles. The inner stator is a surface-mounted, radially magnetized (NS) permanent magnet. Therefore, in this specific double-sided motor, the number of pole pairs p of the inner stator... s =6, number of pole pairs n of rotor modulation block r =10. The overall structure diagram of the dual-sided motor is shown in Figure 1. The arrows indicate the magnetization direction of the inner stator permanent magnets. The shape of the permanent magnets is customizable. The rotor modulation block structure diagram is shown in Figure 1. Figure 2 As shown.

[0064] The magnetomotive force of the permanent magnet is modified to a sinusoidal shape, and its shape is changed to a willow leaf shape, narrow at both ends and wide in the middle, so that the magnetomotive force of the permanent magnet is distributed sinusoidally in the magnetization direction. Next, the Fourier decomposition method is used to determine the number of fundamental pole pairs of the permanent magnet during rotation and at rest; finally, the levitation winding is wound according to the conditions for the generation of levitation force, as shown in Figure 3.

[0065] Step S1: Using the Fourier decomposition method, since the permanent magnet is stationary on the surface of the inner stator,

[0066]

[0067] The permanent magnet itself generates 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, belonging to stationary waves. When the shape of the permanent magnet is modified, the magnetomotive force 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.

[0068] At this point, the number of pole pairs of the modulation block is 10, and the Fourier expression for the air gap permeability of the modulation block is:

[0069]

[0070] Since the air gap magnetic flux density is equal to the product of the magnetomotive force and the air gap permeability, the Fourier expression for the air gap magnetic flux density is:

[0071]

[0072] It can be seen that the magnetic field generated by the permanent magnet, after being modulated by the modulator block, will produce rotating magnetic fields in the air gap with pole pair numbers of k*10+(2i-1)*6 and |k*10-(2i-1)*6|, where k=1,2,3,…, and the rotational speed of the magnetic field with pole pair number of k*10+(2i-1)*6 is… The rotational speed of a magnetic field with |k*10-(2i-1)*6| pole pairs is

[0073] Step S2: Considering the main magnetic field pole pair number, k = 1 is chosen. Since a magnetic field with 16 pole pairs is too high, when the winding is wound with 16 pole pairs, the higher harmonic components of the winding are used, and their amplitude is very small, contributing little to the levitation force. Therefore, they are not considered when analyzing the levitation winding. Thus, only the magnetic field with 4 pole pairs is analyzed. As previously known, the permanent magnet itself generates a stationary magnetic field with (2i-1)*6 pole pairs in the motor air gap. After the permanent magnet magnetomotive force becomes sinusoidal, this magnetic field only has a stationary magnetic field with 6 pole pairs, and its electric angular velocity is zero. When k = 1, the modulated magnetic field has 4 pole pairs, and the rotational speed of this magnetic field is... Its electric angular velocity is Therefore, at this time, there is a magnetic field with 6 pole pairs generated by the permanent magnet itself in the air gap. This magnetic field has a rotational speed of zero and is a stationary wave with an electric angular velocity of zero. There is also a magnetic field with 4 pole pairs modulated by the modulation block, and the rotational speed of this magnetic field is... Its electric angular velocity is

[0074] Step S3: According to the conditions for the generation of levitation force, a controllable levitation force can only be generated in the motor when the number of pole pairs of the two magnetic fields in the air gap differs by one pole and the electric angular velocities of the two magnetic fields are the same. As can be seen from step S2, the number of pole pairs of the rotating magnetic field in the air gap is 4 at this time, so the levitation winding can be wound into 3 or 5 pole pairs.

[0075] Step S4: Considering the proposed constraints, when the number of pole pairs of the rotating magnetic field in the air gap is 4, satisfying 4 = 6 - 2, the first winding method is to wind the suspension winding into 5 pole pairs. At this time, the winding will generate a magnetic field harmonic with 5 pole pairs in the air gap, and the rotational speed of this magnetic field is... Its electric angular velocity is After being modulated by the modulator, the 5th harmonic generates a magnetic field with 10 - 5 = 5 pole pairs in the air gap. This magnetic field has zero rotational speed and is considered a stationary wave, with an electric angular velocity of zero. At this time, the magnetic field with 6 pole pairs generated by the permanent magnet itself and the magnetic field with 5 pole pairs generated by the suspension winding after being modulated by the modulator satisfy the condition that the number of pole pairs differs by one and that the electric angular velocities are the same and both are zero, which can generate a stable levitation force. In addition, the magnetic field with 4 pole pairs generated by the permanent magnet after being modulated by the modulator and the magnetic field with 7 pole pairs generated by the suspension winding itself satisfy the condition that the number of pole pairs differs by one and that the electric angular velocities are the same and both are 10Ω. r This can generate a stable levitation force. However, at this time, the magnetic field with 6 pole pairs generated by the permanent magnet itself and the magnetic field with 5 pole pairs generated by the levitation winding itself satisfy the condition that the number of pole pairs differs by one, but the electric angular velocities of the two magnetic fields are different. The former has an electric angular velocity of zero, while the latter has an electric angular velocity of 10Ω. r The two magnetic fields will generate levitation force pulsations, and the levitation winding is wound with 5 pairs of poles. Figure 4 As shown, the levitation force of the motor at this time is as follows: Figure 5 As shown, the motor's levitation force pulsates significantly at this point, and the motor cannot generate a stable levitation force. In summary, under these conditions, when the levitation winding is wound with 5 pole pairs, the motor will generate a levitation force with significant pulsations and cannot produce a stable levitation force. The second winding method involves winding the levitation winding with 3 pole pairs. In this case, the winding will generate a magnetic field harmonic with 3 pole pairs in the air gap, and the rotational speed of this magnetic field is... Its electric angular velocity is After being modulated by the modulator, the third harmonic generates a magnetic field with 10 - 3 = 7 pole pairs in the air gap. This magnetic field has zero rotational speed and is considered a stationary wave, with an electric angular velocity of zero. At this time, the magnetic field with 6 pole pairs generated by the permanent magnet itself and the magnetic field with 7 pole pairs generated by the suspension winding after being modulated by the modulator satisfy the condition that the number of pole pairs differs by one and that the electric angular velocities are the same and both are zero, which can generate a stable levitation force. In addition, the magnetic field with 4 pole pairs generated by the permanent magnet after being modulated by the modulator and the magnetic field with 3 pole pairs generated by the suspension winding itself satisfy the condition that the number of pole pairs differs by one and that the electric angular velocities are the same and both are 10Ω. r This can generate a stable levitation force. In summary, when the levitation winding is wound into 3 pairs of poles, the motor will theoretically generate a relatively stable levitation force.

[0076] However, the above analysis does not consider the cancellation constraints between the armature magnetic field harmonics and the permanent magnet harmonics before modulation (Constraint 1), and the cancellation constraints between the armature magnetic field harmonics and the permanent magnet harmonics after modulation (Constraint 2). The levitation winding is wound with 3 pairs of poles. Figure 6 As shown, the levitation force of the motor at this time is as follows: Figure 7 As shown, when considering harmonics, the levitation force pulsation of the 3-pole motor will increase significantly, such as... Figure 7As shown. This is because the fifth harmonic of the three-pole suspended magnetic field has 15 poles (electrical frequency of 10Ω). r After modulation with six pairs of permanent magnets, there are 14 pairs of poles (electrical frequency of 20Ω). r The harmonic magnetic field of the two generates pulsating levitation force.

[0077] The flowchart of the general construction method of the bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to the three steps of the present invention is as follows: Figure 8 As shown.

[0078] An example of a motor designed according to the three steps of this invention is as follows:

[0079] like Figure 9 As shown, the permanent magnet has 8 pole pairs and the tuning blocks are 12. The modulated permanent magnet magnetic field is expressed as follows:

[0080] (1) 8 pole pairs (stationary), (2) 20 pole pairs (electric angular frequency of 12Ω) r (3) 32 pairs of electrodes (electric angular frequency of 24Ω) r (4) 32 pairs of electrodes (electric angular frequency of 36Ω) r (5) 4 pairs of electrodes (electric angular frequency of 12Ω) r (6) 16 pairs of electrodes (electric angular frequency of 24Ω) r (7) 28 pairs of electrodes (electric angular frequency of 36Ω) r ).

[0081] The levitation magnetic field has 5 pole pairs. The levitation magnetic field before modulation is expressed as follows:

[0082] (1) 5 pairs of poles (electric angular frequency of 12Ω) r (2) 25 pairs of electrodes (electric angular frequency of 12Ω) r (3) 35 pairs of electrodes (electric angular frequency of -12Ω) r ).

[0083] The modulated levitation magnetic field is expressed as follows:

[0084] (1) 17 pole pairs (electric angular frequency of 24Ω) r (2) 7 pairs of poles (stationary), (3) 37 pairs of poles (electric angular frequency of 24Ω) r (4) 13 pairs of poles (stationary), (5) 47 pairs of poles (stationary), (6) 23 pairs of poles (electric angular frequency of -24Ω) r ).

[0085] It can be seen that, by employing the fundamental harmonic global cancellation scheme of this invention, none of the fundamental and harmonic magnetic fields differ in a pair of poles or have unequal electrical angular frequencies. Therefore, the levitation force pulsation of the motor is relatively small. Figure 10 As shown.

[0086] In summary, without considering the fundamental harmonic global cancellation constraint condition proposed in this invention, the traditional suspension motor and the design method described in the document "A Construction Method of a Bilateral Suspension Motor (Application No. 202210891366.7)" result in significant suspension force pulsation, which can lead to unstable motor suspension in severe cases. The motor designed with the fundamental harmonic global cancellation constraint condition proposed in this invention exhibits minimal suspension force pulsation and can achieve stable suspension.

[0087] The above description is only a preferred embodiment of the present invention. This scheme can also be used to design the suspension winding for other double-sided motors with toothed grooves. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A general construction method for a bearingless, dual-sided magnetic gear motor with global cancellation of fundamental harmonics, characterized in that, include: 1) preliminary optimization of the number of pole pairs p of the permanent magnets s , the number of modulation blocks n r and the number of pole pairs of the levitation magnetic field, in order to eliminate the pulsations of the levitation force generated by the fundamental of the levitation magnetic field and the stationary waves of the permanent magnets; 2) For p determined in step 1), s n r The armature magnetic field harmonics before modulation with the number of pole pairs of the levitation magnetic field are canceled out to eliminate the levitation force pulsation generated by the armature magnetic field harmonics before modulation and the permanent magnet harmonics. 3) For p determined in step 2), s n r The armature magnetic field harmonics modulated with the number of pole pairs of the levitation magnetic field are canceled out by the harmonics of the permanent magnet, so as to eliminate the levitation force pulsation generated by the modulated armature magnetic field harmonics and the harmonics of the permanent magnet. 4) Based on the number of floating pole pairs W determined in step 3), design the number of external stator slots.

2. The general construction method of a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to claim 1, characterized in that, Step 1) specifically includes: determining the number of permanent magnet pole pairs and the number of modulation blocks, and shaping the magnetomotive force of the permanent magnet into a sine wave; using Fourier decomposition to determine the number of fundamental pole pairs of the permanent magnet during rotation and at rest; winding the suspension winding according to the conditions for the generation of suspension force, and setting constraints to optimize the winding of the suspension winding in order to reduce the pulsation of suspension force under multi-harmonic operation.

3. The general construction method of a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to claim 2, characterized in that, 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 At -2, the suspension winding is wound into (n r -p s -1) Pole pairs; 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 At +2, the levitation winding is wound into (n r -p s +1) Pole pairs; when the number of pole pairs of the rotating magnetic field in the air gap is (n r -p s (n) does not satisfy r -p s ) = p s When ±2, the suspension winding is wound into (n r -p s -1) polar or (n) r -p s +1).

4. A general construction method for a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to claim 3, characterized in that, For P determined in step 1), s n r Cancellation constraints between armature magnetic field harmonics and permanent magnet harmonics before modulation with the number of pole pairs of the levitation magnetic field: If the number of suspended pole pairs obtained from step 1) is |n r -P s If |+1, then |n r -P s |+1 needs to satisfy the following constraints: (1)|n r -P s +1 ≠ P s ±1 and |n r -P s +1 ≠ 2n r +P s ±1 and |n r -P s +1 ≠ 3n r +P s ±1 and |n r -P s +1 ≠ |2n r -P s |±1 and|n r -P s +1 ≠ |3n r -P s |±1; (2)5(|n r -P s |+1)≠P s ±1 and 5(|n) r -P s |+1)≠2n r +P s ±1 and 5(|n) r -P s |+1)≠3n r +P s ±1 and 5(|n) r -P s |+1)≠|2n r -P s |±1 and 5(|n) r -P s |+1)≠|3n r -P s |±1; (3)7(|n r -P s |+1)≠P s ±1 and 7(|n) r -P s |+1)≠2n r +P s ±1 and 7(|n) r -P s |+1)≠3n r +P s ±1 and 7(|n) r -P s |+1)≠|2n r -P s |±1 and 7(|n) r -P s |+1)≠|3n r -P s |±1 and 7(|n) r -P s |+1)≠n r +P s ±1 and 7(|n) r -P s |+1)≠|n r -P s |±1; If the number of suspended pole pairs obtained from step 1) is |n r -P s If |-1, then |n r -P s |-1 needs to satisfy the following constraint: (1)|n r -P s -1 ≠ P s ±1 and |n r -P s -1 ≠ 2n r +P s ±1 and |n r -P s -1 ≠ 3n r +P s ±1 and |n r -P s -1 ≠ |2n r -P s |±1 and|n r -P s |-1≠|3n r -P s |±1; (2)5(|n r -P s |-1)≠P s ±1 and 5(|n) r -P s |-1)≠2n r +P s ±1 and 5(|n) r -P s |-1)≠3n r +P s ±1 and 5(|n) r -P s |-1)≠|2n r -P s |±1 and 5(|n) r -P s |-1)≠|3n r -P s |±1; (3)7(|n r -P s |-1)≠P s ±1 and 7(|n) r -P s |-1)≠2n r +P s ±1 and 7(|n) r -P s |-1)≠3n r +P s ±1 and 7(|n) r -P s |-1)≠|2n r -P s |±1 and 7(|n) r -P s |-1)≠|3n r -P s |±1 and 7(|n) r -P s |-1)≠n r +P s ±1 and 7(|n) r -P s |-1)≠|n r -P s |±1.

5. A general construction method for a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to claim 3, characterized in that, For P determined in step 2), s n r The cancellation constraint between the armature magnetic field harmonics modulated by the number of pole pairs of the levitation magnetic field and the harmonics of the permanent magnet: If the number of suspended pole pairs obtained from step 2) is |n r -P s If |+1, then |n r -P s |+1 needs to satisfy the following constraints: (1)|n r -P s |+1+n r ≠P s ±1 and |n r -P s |+1+n r ≠n r +P s ±1 and |n r -P s |+1+n r ≠3n r +P s ±1 and |n r -P s |+1+n r ≠|n r -P s |±1 and|n r -P s |+1+n r ≠|3n r -P s |±1; (2)||n r -P s |+1-n r |≠n r +P s ±1 and ||n r -P s |+1-n r |≠2n r +P s ±1 and ||n r -P s |+1-n r |≠3n r +P s ±1 and ||n r -P s |+1-n r |≠|2n r -P s |±1 and||n r -P s |+1-n r |≠|3n r -P s |±1 and||n r -P s |+1-n r |≠|n r -P s |±1 (3)|n r -P s |*5+5+n r ≠P s ±1 and |n r -P s |*5+5+n r ≠n r +P s ±1 and |n r -P s |*5+5≠3n r +P s ±1 and |n r -P s |*5+5+n r ≠|n r -P s |±1 and|n r -P s |*5+5+n r ≠|3n r -P s |±1; (4)||n r -P s |*5+5-n r |≠n r +P s ±1 and ||n r -P s |*5+5-n r |≠2n r +P s ±1 and ||n r -P s |*5+5-n r |≠3n r +P s ±1 and ||n r -P s |*5+5-n r |≠|2n r -P s |±1 and||n r -P s |*5+5-n r |≠|3n r -P s |±1 and||n r -P s |*5+5-n r |≠|n r -P s |±1; (5)|n r -P s |*7+7+n r ≠2n r +P s ±1 and |n r -P s |*7+7+n r ≠n r +P s ±1 and |n r -P s |*7+7≠3n r +P s ±1 and |n r -P s |*7+7+n r ≠|n r -P s |±1 and|n r -P s |*7+7+n r ≠|3n r -P s |±1 and|n r -P s |*7+7+n r ≠|2n r -P s |±1; (6)||n r -P s |*7+7-n r |≠n r +P s ±1 and ||n r -P s |*7+7-n r |≠2n r +P s ±1 and ||n r -P s |*7+7-n r |≠3n r +P s ±1 and ||n r -P s |*7+7-n r |≠|2n r -P s |±1 and||n r -P s |*7+7-n r |≠|3n r -P s |±1 and||n r -P s |*7+7-n r |≠|n r -P s |±1 and||n r -P s |*7+7-n r |≠P s ±1; If the number of suspended pole pairs obtained from step 2) is |n r -P s If |-1, then |n r -P s |-1 needs to satisfy the following constraint: (1)|n r -P s |-1+n r ≠P s ±1 and |n r -P s |-1+n r ≠n r +P s ±1 and |n r -P s |-1+n r ≠3n r +P s ±1 and |n r -P s |-1+n r ≠|n r -P s |±1 and|n r -P s |-1+n r ≠|3n r -P s |±1; (2)||n r -P s |-1-n r |≠n r +P s ±1 and ||n r -P s |-1-n r |≠2n r +P s ±1 and ||n r -P s |-1-n r |≠3n r +P s ±1 and ||n r -P s |-1-n r |≠|2n r -P s |±1 and||n r -P s |-1-n r |≠|3n r -P s |±1 and||n r -P s |-1-n r |≠|n r -P s |±1 (3)|n r -P s |*5-5+n r ≠P s ±1 and |n r -P s |*5-5+n r ≠n r +P s ±1 and |n r -P s |*5-5≠3n r +P s ±1 and |n r -P s |*5-5+n r ≠|n r -P s |±1 and|n r -P s |*5-5+n r ≠|3n r -P s |±1; (4)||n r -P s |*5-5-n r |≠n r +P s ±1 and ||n r -P s |*5-5-n r |≠2n r +P s ±1 and ||n r -P s |*5-5-n r |≠3n r +P s ±1 and ||n r -P s |*5-5-n r |≠|2n r -P s |±1 and||n r -P s |*5-5-n r |≠|3n r -P s |±1 and||n r -P s |*5-5-n r |≠|n r -P s |±1; (5)|n r -P s |*7-7+n r ≠2n r +P s ±1 and |n r -P s |*7-7+n r ≠n r +P s ±1 and |n r -P s |*7-7≠3n r +P s ±1 and |n r -P s |*7-7+n r ≠|n r -P s |±1 and|n r -P s |*7-7+n r ≠|3n r -P s |±1 and|n r -P s |*7-7+n r ≠|2n r -P s |±1; (6)||n r -P s |*7-7-n r |≠n r +P s ±1 and ||n r -P s |*7-7-n r |≠2n r +P s ±1 and ||n r -P s |*7-7-n r |≠3n r +P s ±1 and ||n r -P s |*7-7-n r |≠|2n r -P s |±1 and||n r -P s |*7-7-n r |≠|3n r -P s |±1 and||n r -P s |*7-7-n r |≠|n r -P s |±1 and||n r -P s |*7-7-n r |≠P s ±1.

6. A general construction method for a bearingless magnetic gear double-sided motor with global fundamental harmonic cancellation according to claim 1, characterized in that, The number of external stator slots is 2*3*W, which makes the floating winding 3-phase and the winding form an integer number of slots.

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