Magnetic levitation planar motor

Abstract

The application discloses a magnetic suspension plane motor and belongs to the technical field of magnetic suspension plane motors. The magnetic suspension plane motor comprises a stator and a mover. The mover comprises a permanent magnet array. The stator comprises an X-direction stator coil group and a Y-direction stator coil group. The X-direction stator coil group and the Y-direction stator coil group each comprise at least two layers of stator coils arranged in layers in a direction away from the permanent magnet array. The conductor width of each layer of stator coils in the X-direction stator coil group and the Y-direction stator coil group is sequentially reduced, and the conductor width of the X-direction stator coil at the same level is the same as that of the Y-direction stator coil. The application solves the problem that the existing magnetic suspension plane motor is difficult to maintain constant electromagnetic force while suppressing electromagnetic force pulsation.

Description

Technical Field

[0001] This invention relates to the field of magnetic levitation planar motor technology, and more particularly to a magnetic levitation planar motor. Background Technology

[0002] Magnetic levitation planar motors have the characteristics of no mechanical contact, low motion friction, high positioning accuracy, and the ability to achieve multi-degree-of-freedom motion. They are widely used in high-precision motion platforms such as semiconductor manufacturing, precision machining, and precision measurement.

[0003] Existing magnetic levitation planar motors typically use a stator and a mover to generate electromagnetic force. The stator includes stator coil groups in the X direction and stator coil groups in the Y direction, which are orthogonally arranged to generate electromagnetic forces in the X and Y directions respectively. To facilitate stator manufacturing and parameter design, the stator layers in the same direction usually use the same or similar conductor widths, and electromagnetic force pulsation is reduced by adjusting the size of the permanent magnets in the mover, the stator structure, or the drive current.

[0004] However, the magnetic field generated by the mover typically contains higher-order magnetic field harmonics. These harmonics interact with the current in the stator coils, producing periodic electromagnetic force pulsations. Because the vertical distance between each layer of stator coils and the permanent magnet array in the mover varies in the same direction, the magnetic field amplitude and harmonic content differ at each layer of stator coils. Using the same conductor width makes it difficult to adjust the harmonic coupling degree for each layer's magnetic field characteristics. Increasing the conductor width uniformly to suppress higher-order magnetic field harmonics easily reduces the coupling degree between the stator coils and the fundamental magnetic field, resulting in a loss of constant electromagnetic force. Therefore, existing magnetic levitation planar motors struggle to effectively suppress electromagnetic force pulsations while maintaining a high level of constant electromagnetic force. Summary of the Invention

[0005] The present invention aims to provide a magnetically levitated planar motor.

[0006] To address the problem that existing magnetic levitation planar motors struggle to maintain a constant electromagnetic force level while suppressing electromagnetic force pulsation, the technical solution of this invention is: This invention provides a magnetically levitated planar motor, comprising a stator and a mover: the mover includes a permanent magnet array; the stator includes an X-direction stator coil group and a Y-direction stator coil group, each including at least two layers of stator coils arranged in a direction away from the permanent magnet array; the conductor width of each layer of stator coils in the X-direction and Y-direction stator coil groups decreases sequentially, and the conductor width of the X-direction stator coils at the same level is the same as that of the Y-direction stator coils. By decreasing the conductor width of each layer of stator coils sequentially away from the permanent magnet array, the differential modulation effect of constant electromagnetic force and electromagnetic force harmonics can be utilized using different linewidths, suppressing electromagnetic force pulsation while maintaining a constant electromagnetic force level; simultaneously, the use of the same linewidth for the X-direction and Y-direction stator coils at the same level is beneficial for improving the consistency of electromagnetic performance in the X and Y directions.

[0007] Optionally, along the direction away from the permanent magnet array, the stator coils in the X-direction stator coil group and the stator coils in the Y-direction stator coil group are alternately stacked, and adjacent X-direction stator coils and Y-direction stator coils are orthogonal to each other. This facilitates the formation of a compact and regularly arranged orthogonal stator structure, reduces the difference in spatial arrangement between the X-direction stator coil group and the Y-direction stator coil group, and improves the consistency of electromagnetic effects in the two directions.

[0008] Optionally, the stator coils are all distributed three-phase windings formed using printed circuit board (PCB) technology, with an insulating layer between adjacent layers of stator coils. This insulating layer can be a PCB substrate or an insulating film. PCB fabrication allows for precise control of the conductor width of each layer of stator coils, improving the processing accuracy and consistency of stator coils with unequal widths. Furthermore, the insulating layer enables electrical isolation between adjacent stator coils.

[0009] Optionally, the feature is that the conductor width of each layer of stator coils is: ; in, Indicates the first The conductor width of the layered stator coil, This indicates the period of the magnetic field of the permanent magnet array. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. This represents the total constant electromagnetic force on the target. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. Represents the force constant. It represents the natural constant. It can directly calculate the corresponding conductor width based on the target constant electromagnetic force of each layer of stator coils, improving the calculation efficiency and repeatability of multi-layer stator coil linewidth design.

[0010] Optionally, the electromagnetic force coefficient of the magnetic levitation planar motor is: ; in, Indicates the first First-order electromagnetic force coefficient, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. This represents the conductor width of the k-th layer stator coil. This indicates the thickness of a single layer of the permanent magnet array stator. This indicates the height of the permanent magnet array. It can quantitatively characterize the influence of permanent magnet array parameters, stator structure parameters, and conductor width on electromagnetic forces of different orders, providing a computational basis for establishing a constant electromagnetic force model and determining the width of each conductor layer.

[0011] Optionally, the constant electromagnetic force model of the stator coil includes: ; in, This represents the constant electromagnetic force of the k-th layer stator coil. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. This indicates the horizontal thrust control current. Denotes the first-order electromagnetic force coefficient; defines the force constant. The specific expression is: ; in, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. Indicates the thickness of a single-layer stator. Indicates the height of the permanent magnet array. Let represent the natural constant; then the expression for the constant electromagnetic force model of a single-layer stator coil is: ; in, Indicates the first The conductor width of the stator coil in each layer. This allows establishing a correspondence between the constant electromagnetic force of a single-layer stator coil and the conductor width, vertical distance, and foundation design parameters; by defining the force constant, it also facilitates the unified calculation and comparison of the constant electromagnetic force of each layer of stator coil.

[0012] Optionally, the expression for the target constant electromagnetic force of each layer of stator coils is: ; in, This represents the target constant electromagnetic force of the k-th layer stator coil. This represents the constant electromagnetic force distribution coefficient of the k-th layer. This represents the target total constant electromagnetic force. It can distribute the target total constant electromagnetic force to each layer of stator coils, providing the corresponding target value for the inverse calculation of the conductor width of each layer of stator coils, and realizing the coordinated design of the output force of each layer of stator coils.

[0013] Optionally, the vertical distance between the k-th layer stator coil and the surface of the permanent magnet is expressed as follows: ; in, This represents the vertical distance between the k-th layer stator coil and the surface of the permanent magnet. Indicates the levitation height of the permanent magnet array. This indicates the thickness of a single layer of the permanent magnet array stator. This indicates the stator layer spacing of the permanent magnet array. It allows determination of the vertical distance between each stator coil layer and the permanent magnet surface based on the actual spatial position of each layer, enabling the constant electromagnetic force model to reflect the attenuation effect of the air gap magnetic field along the vertical direction and improving the accuracy of conductor width calculations.

[0014] Optionally, the sum of the constant electromagnetic force distribution coefficients of each layer is 1. This ensures that the output force distribution of the stator coils in each layer matches the air gap magnetic field strength at the corresponding position, and guarantees that the sum of the target constant electromagnetic forces in each layer equals the total target constant electromagnetic force, avoiding redundant or insufficient distribution of constant electromagnetic forces.

[0015] Optionally, the conductor width of each layer of stator coils meets a preset width constraint, which includes an upper limit and a lower limit for the conductor width. The upper limit of the conductor width is no greater than one-sixth of the magnetic field period of the permanent magnet array, and the lower limit of the conductor width is determined based on the minimum current-carrying capacity of the stator coil. This ensures that the conductor width of each layer of stator coils meets electromagnetic performance requirements while also considering the current-carrying capacity of the stator coil, avoiding adverse effects on electromagnetic force output and engineering implementation caused by excessively large or small conductor widths.

[0016] This invention forms an unequal width structure with progressively decreasing stator coil widths. By utilizing the differential modulation effect of different line widths on constant electromagnetic force and electromagnetic force harmonics, the coils closer to the permanent magnet array bear a larger electromagnetic force output and harmonic suppression effect, while the coils farther away from the permanent magnet array compensate for the constant electromagnetic force, thereby reducing electromagnetic force pulsation while maintaining the electromagnetic force output level.

[0017] To make the above-mentioned features and advantages of the invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0018] Figure 1 A schematic diagram of the magnetic levitation planar motor structure provided by the present invention; Figure 2 A schematic diagram of the overall structure of the multi-layer unequal width stator of the magnetic levitation planar motor provided by the present invention; Figure 3 A schematic diagram illustrating the relationship between the zeroth-order electromagnetic force and the conductor width provided by this invention; Figure 4 A schematic diagram of the relationship between the sixth-order electromagnetic force and the conductor width provided by the present invention; Figure 5 A schematic diagram showing the relationship between the 12th order electromagnetic force and the conductor width provided by the present invention; Figure 6 A schematic diagram comparing the electromagnetic force pulsation waveforms of analytical calculations and finite element simulations of the unequal-width stator provided by this invention. Figure 7 A schematic diagram comparing the electromagnetic force pulsation waveforms of an unequal-width stator and an equal-width stator provided by the present invention.

[0019] In the accompanying drawings, similar reference numerals refer to the same elements. Detailed Implementation

[0020] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely 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 described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0021] This embodiment uses a four-layer stator coil as an example to illustrate the technical solution of the present invention, but the number of layers in the stator coil is not limited to four. In other embodiments, the stator coil can be configured as a multi-layer structure with two or more layers. The specific number of layers can be determined according to the electromagnetic force requirements of the magnetic levitation planar motor, the stator thickness, heat dissipation conditions, and magnetic field harmonic compensation requirements.

[0022] The following example uses a four-layer stator coil. The four layers of stator coils arranged sequentially in the direction away from the mover are referred to as the first layer stator coil, the second layer stator coil, the third layer stator coil, and the fourth layer stator coil, respectively.

[0023] Please see Figure 1 This invention provides a planar magnetically levitated motor with an unequal-width stator, comprising a mover 1 and a stator 2; the mover includes a first permanent magnet array 11, a second permanent magnet array 12, a third permanent magnet array 13, and a fourth permanent magnet array 14. The first permanent magnet array 11 and the third permanent magnet array 13 can be grouped together, with their magnetization directions being the same; the second permanent magnet array 12 and the fourth permanent magnet array 14 can be grouped together and orthogonally arranged with the first group.

[0024] The stator 2 includes an X-direction stator coil group 21 and a Y-direction stator coil group 22. Both the X-direction stator coil group 21 and the Y-direction stator coil group 22 include a first layer of stator coils, a second layer of stator coils, a third layer of stator coils, and a fourth layer of stator coils arranged sequentially along the direction away from the permanent magnet array.

[0025] Please see Figure 2 The X-direction stator coil group 21 includes: an X-direction first layer stator coil 211, an X-direction second layer stator coil 212, an X-direction third layer stator coil 213, and an X-direction fourth layer stator coil 214; the Y-direction stator coil group 22 includes: a Y-direction first layer stator coil 221, a Y-direction second layer stator coil 222, a Y-direction third layer stator coil 223, and a Y-direction fourth layer stator coil 224.

[0026] In this embodiment, the stator coil is not formed using traditional wire winding, but rather using printed circuit board technology. Each layer of the stator coil includes multiple strip conductors disposed on a corresponding conductive layer. Each strip conductor extends along a predetermined direction, and each strip conductor has pins at its ends for electrical connection. In this embodiment, the corresponding pins are soldered together using connecting wires, so that the corresponding strip conductors form a closed current loop according to a predetermined electrical connection relationship, thereby constituting a stator coil for carrying drive current and generating electromagnetic force. Please continue reading. Figure 2 In the diagram, the "·" and "×" symbols on each strip conductor indicate the preset current direction within the strip conductor. "·" indicates that the current flows outwards perpendicular to the plane of the diagram, while "×" indicates that the current flows inwards perpendicular to the plane of the diagram. Therefore, the stator coil described herein refers to an integral structure with electromagnetic force generation function, formed by multiple strip conductors and their electrical connections. These strip conductors are the current-carrying conductors constituting the stator coil.

[0027] The strip conductor extends along a predetermined direction within the plane of the printed circuit board and has two opposite sides located on either side of its extension direction. The conductor width described herein refers to the distance between the two opposite sides measured along a direction perpendicular to the extension direction of the strip conductor within the plane of the printed circuit board. Each strip conductor in the same layer of stator coils may have the same conductor width.

[0028] Along the direction away from the permanent magnet array, the conductor width of each layer of stator coils in the X-direction stator coil group 21 and the Y-direction stator coil group 22 decreases sequentially, and the conductors of the X-direction stator coils and Y-direction stator coils in the same layer are the same.

[0029] Specifically, in the X-direction stator coil group 21 and the Y-direction stator coil group 22, the first layer stator coil, the second layer stator coil, the third layer stator coil, and the fourth layer stator coil are collectively referred to as the k-th layer stator coil, and the conductor width of the strip conductor in the k-th layer stator coil is denoted as... .

[0030] Please continue reading. Figure 1 The diagram shows the relative positions of the stator and rotor. The stator is a three-phase full-pitch winding, and a single-layer stator consists of multiple coil arrays. Four layers of stator coils are placed orthogonally in both the X and Y directions. The four layers of stator coils in the same direction are arranged sequentially away from the permanent magnet array. The conductor width of each layer of stator coils satisfies the following conditions. The layers decrease in thickness. Insulating material separates the layers, and each stator layer has the same thickness.

[0031] As an example, the X-direction stator coil group and the Y-direction stator coil group are stacked alternately in the following order: first layer stator coil 211 in the X direction, first layer stator coil 221 in the Y direction, second layer stator coil 212 in the X direction, second layer stator coil 222 in the Y direction, third layer stator coil 213 in the X direction, third layer stator coil 223 in the Y direction, fourth layer stator coil 214 in the X direction, and fourth layer stator coil 224 in the Y direction.

[0032] The conductor widths of the first-layer stator coil 211 in the X direction and the first-layer stator coil 221 in the Y direction are both... The conductor widths in the second-layer stator coil 212 in the X direction and the second-layer stator coil 222 in the Y direction are both The conductor widths in the third-layer stator coil 213 in the X direction and the third-layer stator coil 223 in the Y direction are both The conductor widths in the fourth layer stator coil 214 in the X direction and the fourth layer stator coil 224 in the Y direction are both .

[0033] Thus, the stator coil groups in the X direction and the stator coil groups in the Y direction together form an eight-layer stator structure. The conductor widths of the four stator coils in the X direction and the four stator coils in the Y direction are set according to their respective vertical distances from the permanent magnet array, and the stator coil groups in the X direction and the stator coil groups in the Y direction are designed with unequal widths independently.

[0034] As an example, the stator is manufactured using printed circuit board technology, and each layer of stator coils is a distributed three-phase winding disposed on the corresponding conductive layer, with a printed circuit board substrate or insulating material disposed between adjacent stator coils.

[0035] Specifically, during the printed circuit board (PCB) fabrication process, the copper foil trace dimensions are set according to the conductor widths of the stator coils from the first to the fourth layer, ensuring that the stator coils in different conductive layers have corresponding conductor widths. Therefore, the conductor widths of each stator coil layer can be controlled through PCB fabrication parameters.

[0036] A printed circuit board substrate or additional insulating material is disposed between adjacent stator coils. The printed circuit board substrate or additional insulating material is used to isolate adjacent conductive layers, prevent electrical connections between adjacent stator coils, and support and position the multilayer stator coils.

[0037] The use of printed circuit board technology enables precise machining of conductor widths in each layer of stator coils and improves dimensional consistency in the manufacturing process of multi-layer stators with unequal widths. At the same time, the use of printed circuit board substrates or insulating materials enables electrical insulation between each layer of stator coils.

[0038] The basic design parameters include the magnetic field period of the permanent magnet array. Single-layer stator thickness Stator layer spacing Suspension height Remanence of permanent magnets Height of permanent magnet array Length of permanent magnet array and horizontal thrust control current .

[0039] Specifically, based on the aforementioned suspension height The thickness of the single-layer stator and the stator layer spacing The vertical distance between the k-th layer stator coil and the surface of the permanent magnet is determined by the following expression: ; in, This represents the vertical distance between the k-th layer stator coil and the surface of the permanent magnet. Indicates the levitation height of the permanent magnet array. This indicates the thickness of a single layer of the permanent magnet array stator. This indicates the stator layer spacing of the permanent magnet array.

[0040] Since the air gap magnetic field strength decreases as the vertical distance between the stator coil and the permanent magnet array increases, by determining the vertical distance between each layer of stator coil, the difference in magnetic field strength at the location of each layer of stator coil can be characterized, providing a basis for positional parameters for establishing a constant electromagnetic force model and allocating the target constant electromagnetic force for each layer.

[0041] Specifically, the electromagnetic force coefficient is determined based on the aforementioned basic design parameters. The specific expression is: ; in, Indicates the first First-order electromagnetic force coefficient, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. This represents the conductor width in the k-th layer of the stator coil. This indicates the thickness of a single layer of the permanent magnet array stator. This indicates the height of the permanent magnet array.

[0042] As can be seen from the above expressions, the electromagnetic force coefficients of different orders are all affected by the conductor width, and the conductor width has different degrees of influence on the fundamental electromagnetic force and higher harmonic electromagnetic forces. Therefore, the electromagnetic force coefficients can quantitatively characterize the differentiated modulation effect of conductor width on constant electromagnetic force and electromagnetic force harmonics of different orders, providing a calculation basis for balancing constant electromagnetic force output and electromagnetic force pulsation suppression.

[0043] For a constant electromagnetic force, with the order N of the electromagnetic force set to 1, the constant electromagnetic force generated by the k-th layer stator coil is expressed as: ; in, This represents the constant electromagnetic force of the k-th layer stator coil. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. This indicates the horizontal thrust control current. This represents the first-order electromagnetic force coefficient; The first-order electromagnetic force coefficient Substituting into the above expression for constant electromagnetic force, and defining the parameter terms that are independent of the stator coil layer and conductor width as force constants. The specific expression is: ; in, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. Indicates the thickness of a single-layer stator. Indicates the height of the permanent magnet array. Represents the natural constant.

[0044] The expression for the constant electromagnetic force model of a single-layer stator coil is: ; in, Indicates the first The conductor width in the layered stator coil.

[0045] In the constant electromagnetic force model, the exponential term characterizes the attenuation of the air gap magnetic field as the vertical distance increases, and the conductor width-related term characterizes the modulation effect of the conductor width on the constant electromagnetic force. This allows for the establishment of a quantitative relationship between the constant electromagnetic force of each layer of stator coils and its spatial position, conductor width, and basic design parameters, providing a model basis for calculating the conductor width of each layer based on the target constant electromagnetic force.

[0046] Set target total constant electromagnetic force Based on the constant electromagnetic force distribution coefficient of each layer Total constant electromagnetic force on the target The target constant electromagnetic force is obtained by distributing the force among the stator coils of each layer. The specific expression is: ; in, This represents the target constant electromagnetic force of the k-th layer stator coil. This represents the constant electromagnetic force distribution coefficient of the k-th layer. This represents the target total constant electromagnetic force. It can distribute the target total constant electromagnetic force to each layer of stator coils, providing the corresponding target value for the inverse calculation of the conductor width in each layer of stator coils, and realizing the coordinated design of the output force of each layer of stator coils.

[0047] Specifically, the constant electromagnetic force distribution coefficient of each layer is determined based on the air gap magnetic field strength corresponding to the position of the stator coil of each layer and the preset output force distribution of each layer, and the sum of the constant electromagnetic force distribution coefficients of each layer is 1.

[0048] Specifically, the formula for the air gap magnetic field strength corresponding to the location of each layer of stator coils is as follows: ; In the formula, The thickness of the permanent magnet. The residual magnetism of the permanent magnet is denoted as . The air gap magnetic field at the location of the four-layer stator coil is denoted as . , , , .

[0049] Then the constant electromagnetic force distribution coefficient of the k-th layer is: ; As an example, the electromagnetic force distribution coefficient fluctuates up and down according to the designer's requirements. The fluctuation range is determined by the range of line width values. However, the sum of the constant electromagnetic force distribution coefficients of each layer is 1. The constant electromagnetic force distribution coefficient of the first layer needs to be slightly smaller than that of the equal-width structure, and the constant electromagnetic force distribution coefficients of the second, third, and fourth layers need to be slightly larger than that of the equal-width structure to suppress electromagnetic force pulsation.

[0050] Because the air gap magnetic field is stronger where the stator coils are closer to the permanent magnet array and weaker where they are farther away, a constant electromagnetic force distribution coefficient can be set by combining the air gap magnetic field strength of each layer. This allows the target constant electromagnetic force in each layer to match the actual magnetic field distribution. Furthermore, setting the sum of the constant electromagnetic force distribution coefficients for each layer to 1 ensures that the sum of the target constant electromagnetic forces in each layer equals the total target constant electromagnetic force, preventing insufficient or redundant distribution of the target constant electromagnetic force.

[0051] The target constant electromagnetic force of each layer of stator coils Substituting into the constant electromagnetic force model The conductor width in each layer of stator coils is calculated by reverse calculation. The specific expression is as follows: ; in, Indicates the first The conductor width in the layered stator coil, This indicates the period of the magnetic field of the permanent magnet array. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. This represents the total constant electromagnetic force on the target. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. Represents the force constant. Represents the natural constant.

[0052] The above calculations can be used to obtain the conductor widths of each layer that decrease sequentially along the direction away from the permanent magnet array. It should be noted that each layer of stator coils does not only perform electromagnetic force pulsation suppression or constant electromagnetic force compensation, but also participates in both constant electromagnetic force output and electromagnetic force harmonic modulation.

[0053] Among them, the stator coils located near the permanent magnet array have a stronger air gap magnetic field and a relatively larger conductor width, which can expand the spatial integration range of the stator coils with respect to the air gap magnetic field. Therefore, in the combined effect of each layer of stator coils, more emphasis is placed on reducing the electromagnetic force coefficient corresponding to higher magnetic field harmonics, thereby suppressing electromagnetic force pulsation.

[0054] The air gap magnetic field at the location of the stator coils far from the permanent magnet array is relatively weak, and its conductor width is relatively small, which can relatively enhance the coupling effect corresponding to the fundamental electromagnetic force. Therefore, in the joint action of each layer of stator coils, it focuses more on compensating for the loss of constant electromagnetic force caused by the wide line structure and the increase in vertical distance.

[0055] Therefore, through the synergistic effect between the stator coils close to the permanent magnet array and the stator coils far away from the permanent magnet array, it is possible to reduce electromagnetic force pulsation while maintaining a constant electromagnetic force level, thereby achieving synergistic optimization of constant electromagnetic force output and force stability.

[0056] After calculating the conductor width of each layer of stator coils, upper and lower limits are imposed on the conductor width, meaning that the conductor width of each layer of stator coils also satisfies: ; and: ; in, This indicates the maximum conductor width allowed for each layer of stator coils; This indicates the minimum conductor width allowed for each layer of stator coils; This indicates the period of the magnetic field of the permanent magnet array.

[0057] The maximum conductor width is used to limit the range of wide coil settings, preventing excessive reduction in the fundamental frequency coupling of the magnetic field due to excessively large conductor width. The minimum conductor width is determined based on the minimum current-carrying capacity of the stator coils, ensuring that the preset current transmission requirements can still be met even after the conductor width of the second to fourth stator coils is progressively reduced.

[0058] Minimum current carrying capacity is given by the formula In the formula, K is the correction factor, T is the maximum temperature rise, and A is the conductor cross-sectional area. , For conductor width, Given the conductor height, the minimum current carrying capacity is determined based on the motor's rated electromagnetic force and motor load, and the minimum conductor width is calculated using a formula.

[0059] By constraining the upper and lower limits of the conductor width, it is possible to achieve unequal width settings for each layer of stator coils in the X-direction stator coil group 21 and the Y-direction stator coil group 22, while also taking into account the suppression of high-order magnetic field harmonics, constant electromagnetic force output, and the current carrying capacity of the stator coils.

[0060] In one specific embodiment, the basic design parameters of the magnetic levitation planar machine are determined, including the period of the permanent magnet array magnetic field. =16mm; Single-layer stator thickness =0.21mm; stator layer spacing =0.33mm; Suspension height =0.1mm; Remanence of permanent magnet =1.33T; Permanent magnet array height =4mm; Permanent magnet array length =64mm; Horizontal thrust control current =7A.

[0061] In this embodiment, the constant electromagnetic force distribution coefficients for each layer They are respectively: , , , The calculated line widths for the four layers are as follows: , , , .

[0062] The calculation results show that the stator coils closer to the permanent magnet array have a relatively large conductor width, which focuses more on using spatial integration to suppress electromagnetic force pulsation; the stator coils farther from the permanent magnet array have a relatively small conductor width, which focuses more on compensating for the loss of constant electromagnetic force caused by the attenuation of the air gap magnetic field and the wide line structure. Thus, through the synergistic effect of each layer of stator coils, electromagnetic force pulsation is reduced while maintaining a constant electromagnetic force level.

[0063] To further verify the effect of the multi-layer unequal-width stator structure used in this embodiment on suppressing electromagnetic force pulsation, the following explanation, based on finite element simulation results, clarifies the accuracy of the analytical calculation results and the difference in electromagnetic force performance between unequal-width and equal-width stators.

[0064] like Figures 3 to 5 This invention provides schematic diagrams showing the relationship between electromagnetic forces of various orders and conductor width. The figures illustrate the relationship between constant electromagnetic force, the 6th harmonic, and the 12th harmonic as a function of conductor width. The variation pattern of the constant electromagnetic force shows a gradual decreasing trend with the increase of linewidth, indicating a negative correlation between linewidth and constant electromagnetic force. The 6th harmonic force is negative, but its absolute value decreases rapidly with increasing linewidth; therefore, a wide-line-width stator can suppress 6th harmonic force pulsations. The 12th harmonic force curve has a zero-crossing point, where the linewidth is approximately 1.23 mm. The curve first decreases and then increases, approaching zero again at 2.46 mm, indicating that the 12th harmonic force can be completely eliminated by specific linewidth values. The differential influence of linewidth on electromagnetic forces of different orders provides theoretical guidance for suppressing force pulsations. By extracting linewidth-related factors from the electromagnetic force coefficient expression, force pulsations can be decomposed into independent contributions of each harmonic order, facilitating the targeted design of linewidths for each layer of stators with unequal widths.

[0065] like Figure 6 The schematic diagram comparing the electromagnetic force pulsation waveforms from analytical calculations and finite element simulations of the unequal-width stator provided by this invention is shown, with a suspension height of 0.1 mm and a control current... Comparison of electromagnetic force pulsation waveforms between analytical calculations and finite element simulations under 7A conditions. In the figure, the solid red line represents the analytical calculation result, the dashed blue line represents the finite element simulation result, the horizontal axis represents the horizontal position x of the mover, and the vertical axis represents the horizontal force. Both curves exhibit periodic fluctuations, with their phases and trends showing a high degree of agreement. The maximum absolute error between the simulation and analytical calculations is less than 0.07N, and the average error is less than 1.5%. The main reason for this error is that the analytical calculation model includes constant electromagnetic force and 6th and 12th force harmonics, without considering the contribution of higher-order force harmonics, while the finite element simulation results represent the superposition of force pulsations of all orders. The simulation results verify the accuracy of the proposed analytical model, demonstrating that the electromagnetic force analytical model upon which this invention is based can accurately describe the electromagnetic force characteristics of stators with unequal widths, providing a reliable calculation tool for the parameter design of stators with unequal widths.

[0066] like Figure 7 The present invention provides a schematic diagram comparing the electromagnetic force pulsation waveforms of an unequal-width stator and a constant-width stator. The simulation parameters for the unequal-width stator are the four-layer linewidth parameters calculated in a specific embodiment, while the four-layer linewidth of the constant-width stator is uniformly 1.5mm. The comparison shows that the unequal-width stator significantly reduces the force pulsation ratio without sacrificing the average electromagnetic force.

[0067] In summary, this invention, by arranging stator coils of unequal width in the same direction, causes the conductor width of each layer of stator coils to decrease sequentially along the direction away from the permanent magnet array. This unequal-width stator structure can suppress electromagnetic force pulsations caused by higher-order magnetic field harmonics while reducing constant electromagnetic force loss and improving the smoothness of the electromagnetic force output of the magnetic levitation planar motor.

[0068] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A magnetically levitated planar motor, characterized in that, Including stator and mover: The mover includes a permanent magnet array; The stator includes an X-direction stator coil group and a Y-direction stator coil group, and both the X-direction stator coil group and the Y-direction stator coil group include at least two layers of stator coils arranged in layers along the direction away from the permanent magnet array; The conductor width of each layer of stator coils in the X-direction stator coil group and the Y-direction stator coil group decreases sequentially, and the conductor width of the X-direction stator coils of the same layer is the same as that of the Y-direction stator coils.

2. The magnetic levitation planar motor as described in claim 1, characterized in that, The conductor widths of each layer of stator coils are: ； in, Indicates the first The conductor width of the layered stator coil, This indicates the period of the magnetic field of the permanent magnet array. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. This represents the total constant electromagnetic force on the target. Indicates the first The constant electromagnetic force distribution coefficient corresponding to the layered stator coils. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. Represents the force constant. Represents the natural constant.

3. The magnetic levitation planar motor as described in claim 1, characterized in that, The stator coils in the X-direction stator coil group and the stator coils in the Y-direction stator coil group are stacked alternately.

4. The magnetic levitation planar motor as described in claim 3, characterized in that, The adjacent stator coils in the X direction are orthogonal to each other in the Y direction.

5. The magnetic levitation planar motor as described in claim 1, characterized in that, An insulating layer is provided between the two adjacent stator coil layers.

6. The magnetic levitation planar motor as described in claim 2, characterized in that, The electromagnetic force coefficient of the magnetic levitation planar motor is: ； in, Indicates the first First-order electromagnetic force coefficient, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. This represents the conductor width of the k-th layer stator coil. This indicates the thickness of a single layer of the permanent magnet array stator. This indicates the height of the permanent magnet array.

7. The magnetic levitation planar motor as described in claim 2, characterized in that, The constant electromagnetic force model of the stator coil includes: ； in, This represents the constant electromagnetic force of the k-th layer stator coil. Indicates the first The vertical distance between the layered stator coil and the surface of the permanent magnet. This indicates the horizontal thrust control current. This represents the first-order electromagnetic force coefficient; Define force constant The specific expression is: ； in, This indicates the remanence of a permanent magnet. This indicates the period of the magnetic field of the permanent magnet array. Indicates the length of the permanent magnet array. Indicates the thickness of a single-layer stator. Indicates the height of the permanent magnet array. Represents the natural constant; The expression for the constant electromagnetic force model of a single-layer stator coil is: ； in, Indicates the first The conductor width of the layered stator coil.

8. The magnetic levitation planar motor as described in claim 2, characterized in that, The target constant electromagnetic force of each layer of stator coils includes: The expression for the target constant electromagnetic force of each layer of stator coils is: ； in, This represents the target constant electromagnetic force of the k-th layer stator coil. This represents the constant electromagnetic force distribution coefficient of the k-th layer. This represents the total constant electromagnetic force at the target.

9. The magnetic levitation planar motor as described in claim 2, characterized in that, The vertical distance between the stator coil of the k-th layer and the surface of the permanent magnet is expressed as follows: ； in, This represents the vertical distance between the k-th layer stator coil and the surface of the permanent magnet. Indicates the suspension height. Indicates the thickness of a single-layer stator. Indicates the stator layer spacing.

10. The magnetic levitation planar motor as described in claim 8, characterized in that, The sum of the constant electromagnetic force distribution coefficients of each layer is 1.

11. The magnetic levitation planar motor as described in claim 2, characterized in that, The conductor width of each layer of stator coils meets the preset width constraint, which includes an upper limit and a lower limit of conductor width; the upper limit of conductor width is not greater than one-sixth of the magnetic field period of the permanent magnet array, and the lower limit of conductor width is determined according to the minimum current carrying capacity of the stator coil.

Images