Electro-magnetic suspension planar motor coil configuration

Abstract

The invention relates to the technical field of magnetic suspension planar motors, and discloses an electro-magnetic magnetic suspension planar motor coil configuration, which comprises a planar motor stator formed by a plurality of equivalent N-pole coils and a plurality of equivalent S-pole coils, the plurality of equivalent N-pole coils are arranged in a rectangular array, each equivalent S-pole coil is arranged among four adjacent equivalent N-pole coils, and the equivalent S-pole coils are arranged in a rectangular array. The middle radius of each equivalent N-pole coil is shrunk, the radiuses of the two ends of each equivalent S-pole coil are shrunk, the sections of the equivalent N-pole coils and the equivalent S-pole coils are double-trapezoid, and the current directions of the equivalent N-pole coils and the equivalent S-pole coils are opposite; the planar motor rotor is positioned above the planar motor stator and is formed by stacking a plurality of layers of ceramic-based printed coil circuit board groups with the same configuration at the same position; a cooling system is arranged on the planar motor stator; thermal demagnetization of the motor can be avoided, array parameters can be adjusted in real time, the harmonic proportion in magnetic field distribution is reduced, the motion precision of the motor is improved, and the purpose of improving the performance of the motor is achieved.

Description

Technical Field

[0001] This invention relates to the field of magnetic levitation planar motor technology, and in particular to a coil configuration for an electrically excited magnetic levitation planar motor. Background Technology

[0002] The motion platform is one of the most critical components of semiconductor processing equipment, and its motion accuracy and speed directly affect product quality and cost. Traditional mechanical transmission machine tools are no longer able to meet the basic accuracy requirements of semiconductor processing due to multiple factors such as nonlinear friction, transmission component backlash, resonance, transmission component contact deformation, creeping phenomenon, and motor cogging effect.

[0003] Currently, motion platforms in the semiconductor processing field can be categorized into coplanar air-floating platforms and magnetically levitated planar motor motion stages based on their non-motion degree-of-freedom constraint methods. Compared to coplanar air-floating platforms, magnetically levitated planar motor motion stages offer advantages such as simpler mechanical structure, direct-drive motion propulsion, and adaptability to vacuum environments. Furthermore, by eliminating mechanical vibrations from any transmission components, the dynamic characteristics and static accuracy of magnetically levitated planar motor systems far surpass those of traditional mechanical transmission machine tools and coplanar air-floating platforms. Their theoretical positioning accuracy can reach the nanometer level, representing the latest solution for meeting the demands of extreme precision.

[0004] In existing magnetic levitation planar motors, the core motion system often employs a Halbach permanent magnet array paired with a rounded rectangular coil array. This approach has several drawbacks: Crystal defects are easily introduced during the sintering process of the permanent magnets, leading to uneven local magnetization. Thermal demagnetization may occur if the operating temperature deviates from the design value. Furthermore, the array parameters cannot be adjusted in real time during operation, resulting in poor controllability. The Halbach array also exhibits high harmonic components in its magnetic field distribution, affecting the upper limit of the motor's theoretical motion accuracy. Summary of the Invention

[0005] This invention proposes an electrically excited magnetic levitation planar motor coil configuration to address the shortcomings of the prior art. It can avoid thermal demagnetization of the motor, enable real-time adjustment of array parameters, reduce the proportion of harmonics in the magnetic field distribution, improve the motor's motion accuracy, and achieve the goal of improving motor performance.

[0006] The technical solution of this invention is: a coil configuration for an electrically excited magnetically levitated planar motor, comprising: The planar motor stator includes multiple equivalent N-pole coils and multiple equivalent S-pole coils. The multiple equivalent N-pole coils are arranged in a rectangular array, and the multiple equivalent S-pole coils are all arranged within the rectangular array of the multiple equivalent N-pole coils. Each equivalent S-pole coil is located between four adjacent equivalent N-pole coils. The middle radius of each equivalent N-pole coil is reduced, and the two ends radius of each equivalent S-pole coil is reduced. The cross-sections of both the equivalent N-pole coils and the equivalent S-pole coils are double trapezoidal. The current directions of the equivalent N-pole coils and the equivalent S-pole coils are opposite. The planar motor mover is located above the planar motor stator, and the planar motor mover is composed of multiple isomorphic ceramic-based printed coil circuit boards stacked in the same position.

[0007] In at least one embodiment of the present invention, the stator of the planar motor is provided with a heat dissipation system. The heat dissipation system includes a bottom plate and a top plate respectively disposed at the bottom and top of a plurality of equivalent N-pole coils and a plurality of equivalent S-pole coils. A cooling channel is formed in the bottom plate. A plurality of heat dissipation pipes are provided on the bottom plate through which the cooling channel is connected. Each heat dissipation pipe is located in a plurality of equivalent N-pole coils and a plurality of equivalent S-pole coils. The top of each of the plurality of equivalent S-pole coils is provided with an annular heat dissipation pipe connected to the cooling channel. The cooling channel is connected to a cooling medium source.

[0008] In at least one embodiment of the present invention, the single-layer printed circuit coil group includes four sets of three-phase coils with the same size parameters. The four sets of three-phase coils are arranged in a rectangular array, and each three-phase coil includes three sets of right-angled rectangular coils arranged in rows.

[0009] In at least one embodiment of the present invention, the right-angled rectangular coil group is composed of several right-angled rectangular wires with coincident center points, parallel long sides, and equidistantly increasing dimensions. The three right-angled rectangular coil groups of the single-layer printed circuit coil group are connected to three-phase currents A, B, and C.

[0010] In at least one embodiment of the present invention, the outer wall of each heat sink is fitted and fixed to the inner wall of the central hole of the equivalent N-pole coil and the equivalent S-pole coil, the top of each heat sink is fixedly connected to the top plate, and an annular heat sink is reserved at the top of each equivalent S-pole coil.

[0011] In at least one embodiment of the present invention, the inner wall of each heat dissipation pipe is provided with a baffle plate so that the coolant in the heat dissipation pipe can flow in and out within the heat dissipation pipe.

[0012] In at least one embodiment of the present invention, the equivalent N-pole coil and the equivalent S-pole coil are both double trapezoidal cross-section rotating bodies. The cross-section of the equivalent N-pole coil is composed of two trapezoids with their short sides connected, and the cross-section of the equivalent S-pole coil is composed of two trapezoids with their long sides connected. The long and short sides of the upper and lower trapezoids of the cross-sections of the equivalent N-pole coil and the equivalent S-pole coil are of equal length but have different heights.

[0013] In at least one embodiment of the present invention, the minimum radius of the equivalent N-pole coil and the equivalent S-pole coil is rs, the maximum radius of the equivalent N-pole coil and the equivalent S-pole coil is 2.375rs, and the upper trapezoidal height of the double trapezoidal cross-section of the equivalent N-pole coil and the equivalent S-pole coil is 0.5rs, and the lower trapezoidal height is 2.5rs.

[0014] In at least one embodiment of the present invention, the pole pitch of the planar motor stator is The standard dimensions of a single-group three-phase coil right-angled rectangle are: .

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention proposes a planar motor stator composed of multiple equivalent N-pole coils and equivalent S-pole coils. The excitation effect of the current on the magnetic field is guaranteed by physical laws. During use, the magnetic field strength can be adjusted in a timely manner by changing the current magnitude, resulting in strong magnetic field controllability and ensuring the stability of the magnetic field distribution during use. This avoids the problems of uneven magnetization, thermal demagnetization, and uncontrollability during use caused by permanent magnet arrays, thereby optimizing motor controllability, reducing systematic errors caused by permanent magnet characteristics, and improving motor performance. Furthermore, applying a reverse DC current of the same value can effectively reduce the proportion of high-order harmonics in the magnetic field distribution above the coil array, optimize the air gap magnetic field distribution, reduce motion errors caused by the irregularity of the stator magnetic field distribution, and improve the motor's motion accuracy.

[0016] 2. The magnetic levitation planar motor mover designed in this invention is manufactured by stacking ceramic-based printed circuit boards. Compared with commonly used FR-4 or polymer substrates, ceramic substrates have higher thermal conductivity and higher structural rigidity, which reduces the deformation of the motor mover caused by uneven temperature distribution during operation and the structural vibration generated during movement, thereby improving the positioning accuracy of the mover.

[0017] 3. This invention proposes a right-angled rectangular coil with equidistantly increased size based on the printed circuit board coil. This avoids the related errors caused by the large proportion of high-order harmonic components of the electromagnetic force in the rounded corner section of the rounded rectangular coil, and also avoids the errors caused by simplifying the analytical solution of the electromagnetic dynamics model of the rounded corner section of the rounded rectangular coil. This further improves the motion accuracy of the motor and enhances the controllability of the motor.

[0018] 4. This invention provides a top plate and a bottom plate located at the top and bottom of the stator of a planar motor, respectively. The bottom plate has cooling channels, heat dissipation pipes connected to the cooling channels and extending into the equivalent N-pole coil and the equivalent S-pole coil, and a heat dissipation ring on the equivalent S-pole coil. When the motor is in use, cooling medium is introduced into the cooling channels so that the cooling medium flows through the heat dissipation pipes and the heat dissipation ring, thereby ensuring the temperature stability and uniformity of the stator excitation coil, improving the reliability of the motor, and extending its lifespan. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the arrangement structure of the mover and stator coils of the present invention; Figure 2 This is a schematic diagram of the stator heat dissipation structure of the present invention; Figure 3 This is a schematic diagram of the equivalent N-pole coil cross-section structure of the present invention; Figure 4 This is a schematic diagram of the equivalent S-pole coil cross-section structure of the present invention; Figure 5 The distribution of the z-axis component of the magnetic field of the double trapezoidal coil stator array used in this invention; Figure 6 This shows the distribution of the y-axis component of the magnetic field in the double trapezoidal coil stator array used in this invention.

[0020] Explanation of reference numerals in the attached figures: 0. Planar motor stator; 11. Equivalent N-pole coil; 12. Equivalent S-pole coil; 2. Planar motor mover; 21. Single-layer PCB coil group; 22. PCB structure board; 3. Heat dissipation system; 31. Base plate; 311. Cooling channel; 32. Top plate; 33. Cooling pipe; 34. Annular heat pipe. Detailed Implementation

[0021] The accompanying drawings in this invention are not strictly drawn to scale, and the specific dimensions and quantity of each structure can be determined according to actual needs. The drawings described in this invention are merely structural schematic diagrams.

[0022] To make the objectives, technical solutions, and advantages 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. Based on the described embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Unless otherwise defined, the technical or scientific terms used herein should have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in this invention do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. Terms such as "inner," "outer," "upper," "lower," "far," "near," "front," and "rear" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0024] In existing magnetic levitation planar motors, the motion core system often adopts a Halbach permanent magnet array combined with a rounded rectangular coil array. This scheme has the following disadvantages: 1. The permanent magnets suffer from uneven magnetization, thermal demagnetization, and poor controllability; 2. The Halbach array has a high harmonic component in its magnetic field distribution, which affects the upper limit of the theoretical motion accuracy of the motor; 3. The electromagnetic force in the rounded corner transition section of the rounded rectangular coil has a high high-order harmonic component, resulting in a large amount of analytical calculation.

[0025] Specifically, thermal demagnetization is a fundamental defect in permanent magnets. When the permanent magnet array deviates from the standard temperature, changes in magnetic field strength due to thermal effects will inevitably occur, thus affecting the magnetic field distribution. Uneven magnetization is a manufacturing defect in current permanent magnets. Current production methods use powder particle sintering, and crystal defects and the sintering process can lead to uneven local magnetization, failing to meet the requirements of higher precision motion control. Poor controllability is due to the fact that the parameters of the permanent magnet array cannot be adjusted during use. Therefore, the real-time feedback of magnetic field strength distribution information during operation cannot be used as a feedback signal to stabilize the magnetic field. Since the excitation intensity and dimensional parameters of the magnets in the permanent magnet array cannot be modified during use, users cannot make timely corrections to the permanent magnet magnetic field based on the magnetic field response and can only replace the magnets based on the magnetic field performance when the motor is stopped.

[0026] To address the aforementioned issues, this invention provides an electrically excited coil configuration to optimize the stator magnetic field distribution regularity and accuracy limits caused by the shortcomings of permanent magnets and Halbach arrays. Furthermore, to optimize the high harmonic components of the electromagnetic force in the rounded corner transition section of the rounded rectangular coil, which result in large analytical calculations and affect control accuracy, this invention provides a rectangular coil configuration based on a ceramic-based printed circuit board. Finally, to ensure the temperature stability and uniformity of the stator electrically excited coil, this invention provides a stator heat dissipation structure.

[0027] Combination Figures 1 to 6 As shown, a coil configuration of an electrically excited magnetically levitated planar motor includes: like Figure 1As shown, the planar motor stator 1 includes multiple equivalent N-pole coils 11 and multiple equivalent S-pole coils 12. The multiple equivalent N-pole coils 11 are arranged in a rectangular array, and the multiple equivalent S-pole coils 12 are all arranged within the rectangular array of multiple equivalent N-pole coils 11. Each equivalent S-pole coil 12 is located between four adjacent equivalent N-pole coils 11. The radius of the middle part of each equivalent N-pole coil 11 is reduced, and the radius of both ends of each equivalent S-pole coil 12 is reduced. The cross-sections of both the equivalent N-pole coils 11 and the equivalent S-pole coils 12 are double trapezoidal. The current directions of the equivalent N-pole coils 11 and the equivalent S-pole coils 12 are opposite. During operation, the equivalent N-pole coils 11 and the equivalent S-pole coils 12 carry direct current with opposite directions and equal amplitudes. The planar motor mover 2 is located above the planar motor stator 1. The planar motor mover 2 is composed of multiple isomorphic ceramic-based printed coil circuit board groups 21 stacked in the same position. During operation, the mover is suspended above the top plate of the heat dissipation structure, and the suspension height is measured by multiple capacitive displacement sensors.

[0028] Specifically, the planar motor stator 1 array is fixed to the workbench plane by a structural plate and resin. During operation, the two types of coils in the planar motor stator array, the equivalent N-pole coil 11 and the equivalent S-pole coil 12, generate a regular magnetic field above the planar motor stator array through the same reverse DC current. The three-phase coils in the planar motor mover 2 are energized with three-phase AC currents A, B, and C, and are suspended above the planar motor stator array and the heat dissipation structure top plate 31 by the electromagnetic force they receive.

[0029] As an alternative embodiment, the heat dissipation system structure is as follows: Figure 2 As shown, the stator 1 of the planar motor is equipped with a heat dissipation system 3. The heat dissipation system 3 includes a base plate 31 and a top plate 32, which are respectively disposed at the bottom and top of multiple equivalent N-pole coils 11 and multiple equivalent S-pole coils 12. The base plate 31 has a cooling channel 311, and multiple heat dissipation pipes 33 are longitudinally inserted on the base plate 31 and connected to the cooling channel 311. Each heat dissipation pipe 33 is located in the multiple equivalent N-pole coils 11 and multiple equivalent S-pole coils 12. The top of each of the multiple equivalent S-pole coils 12 is provided with an annular heat dissipation pipe 34 connected to the cooling channel 311. The cooling channel 311 is connected to a cooling medium source. Specifically, the base plate 31 is mounted on the workpiece stage base. Through holes are machined in the base plate 31 of the heat dissipation structure, and pipes are embedded in them. Figure 2 The cooling channels 311 inside the middle base plate 31 are arranged alternately, and the cooling channels 311 include coolant inlet channels and coolant outlet channels; Figure 3 and Figure 4This is a schematic diagram of the cross-sections of the equivalent N-pole coil and the equivalent S-pole coil in the stator array of a planar motor. The coils are installed and fixed by the heat dissipation structure top plate 32, heat dissipation structure bottom plate 31, heat pipe 33 and encapsulation resin. The cross-sectional areas of the two types of coils are equal. By designing and optimizing the relevant dimensional parameters, high space utilization and high regularity of the magnetic field of the coil array are achieved at the same time, thereby improving the performance related to the mass-to-thrust ratio and motion accuracy of the motor.

[0030] As an alternative embodiment, the single-layer printed circuit coil group 21 includes four sets of three-phase coils with the same size parameters, each set consisting of three sets of right-angled rectangular coils with the same size parameters.

[0031] As an alternative embodiment, the right-angled rectangular coil group is composed of several right-angled rectangular wires with coincident center points, parallel long sides, and equidistantly increasing dimensions. The three right-angled rectangular coil groups of the single-layer printed circuit coil group 21 are connected to three-phase electricity A, B, and C.

[0032] As an alternative embodiment, the outer wall of each heat sink 33 is fitted and fixed to the inner wall of the central hole of the equivalent N-pole coil 11 and the equivalent S-pole coil 12, the top of each heat sink 33 is fixedly connected to the top plate 31, and the top of each equivalent S-pole coil 12 is reserved with a space for the installation of an annular heat sink 34.

[0033] As an alternative embodiment, each heat pipe 33 has a baffle plate on its inner wall so that the coolant in the heat pipe 33 can flow in and out within the heat pipe 33, forming a flow loop to enhance heat dissipation capacity.

[0034] As an alternative embodiment, both the equivalent N-pole coil 11 and the equivalent S-pole coil 12 are double trapezoidal cross-section rotating bodies. The cross-section of the equivalent N-pole coil 11 consists of two trapezoids with their short sides connected, and the cross-section of the equivalent S-pole coil 12 consists of two trapezoids with their long sides connected. The long and short sides of the upper and lower trapezoids of the equivalent N-pole coil 11 and the equivalent S-pole coil 12 are of equal length but have different heights.

[0035] As an alternative embodiment, the minimum radius of the equivalent N-pole coil 11 and the equivalent S-pole coil 12 is rs, the maximum radius of the equivalent N-pole coil 11 and the equivalent S-pole coil 12 is 2.375rs, and the upper trapezoidal height of the double trapezoidal cross-section of the equivalent N-pole coil 11 and the equivalent S-pole coil 12 is 0.5rs, and the lower trapezoidal height is 2.5rs.

[0036] As an alternative embodiment, the pole pitch of the planar motor stator 1 is... The standard dimensions of a single-group three-phase coil right-angled rectangle are: .

[0037] The simulation results of the magnetic field distribution above the stator of the planar motor in the working state of this invention are as follows: Figure 5 and Figure 6 , Figure 5 This is a diagram showing the distribution of the z-axis component of the magnetic field. Figure 6 The diagram shows the distribution of the magnetic field components in the x and y directions. The simulation results show that the magnetic field distribution closely follows the trigonometric function law. In the subsequent calculation of the mover dynamics model, all higher harmonics except the third harmonic can be ignored. This simplifies the dynamics model while ensuring the accuracy of the motor motion and saves control calculation time.

[0038] The formula describes the magnetic field distribution above the stator of a planar motor under operating conditions. L and N in the formula are coefficients related to the coil structure and the magnitude of the excitation current. , These are the fundamental correlation components in the L and N coefficients, respectively. , These are the third harmonic correlation components in the L and N coefficients, respectively.

[0039] (1) like Figure 1 As shown, the motor mover coil 2 is composed of several layers of ceramic-based printed circuit coils 21 stacked together. As shown in the figure, the printed circuit coil group consists of four groups of three-phase coils with the same size parameters. The three-phase coils are composed of three groups of right-angled rectangular coils with the same size parameters. The right-angled rectangular coil group consists of several right-angled rectangular wires with coincident center points, parallel long sides, and equidistantly increasing dimensions. The design of the right-angled rectangles optimizes the problems of high proportion of high-order harmonic components of electromagnetic force in the rounded corner segment of the rounded rectangle configuration and difficulty in calculating analytical solutions, thereby optimizing the controllability of the mover coil and the motion accuracy of the motor.

[0040] The above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit them. The protection scope of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features, such as modifying the size ratio of the stator asymmetric trapezoidal rotating body, the flow direction of the heat dissipation channel, the stator coil layout, etc.; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions implemented in the present invention, and should all be covered within the protection scope of the present invention.

Claims

1. A coil configuration for an electrically excited magnetically levitated planar motor, characterized in that, include: The planar motor stator includes multiple equivalent N-pole coils and multiple equivalent S-pole coils. The multiple equivalent N-pole coils are arranged in a rectangular array, and the multiple equivalent S-pole coils are all arranged within the rectangular array of the multiple equivalent N-pole coils. Each equivalent S-pole coil is located between four adjacent equivalent N-pole coils. The middle radius of each equivalent N-pole coil is reduced, and the two ends radius of each equivalent S-pole coil is reduced. The cross-sections of both the equivalent N-pole coils and the equivalent S-pole coils are double trapezoidal. The current directions of the equivalent N-pole coils and the equivalent S-pole coils are opposite. The planar motor mover is located above the planar motor stator, and the planar motor mover is composed of multiple printed coil circuit boards stacked in the same position.

2. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 1, characterized in that, The single-layer printed circuit coil group includes four sets of three-phase coils with the same size parameters. The four sets of three-phase coils are arranged in a rectangular array, and each three-phase coil includes three sets of right-angled rectangular coils arranged in rows.

3. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 1, characterized in that, The planar motor stator is equipped with a heat dissipation system, which includes a base plate and a top plate respectively disposed at the bottom and top of multiple equivalent N-pole coils and multiple equivalent S-pole coils. The base plate has a cooling channel and multiple heat dissipation pipes connected to the cooling channel. Each heat dissipation pipe is located inside the multiple equivalent N-pole coils and multiple equivalent S-pole coils. The top of each of the multiple equivalent S-pole coils is provided with an annular heat dissipation pipe connected to the cooling channel. The cooling channel is connected to a cooling medium source.

4. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 2, characterized in that, The right-angled rectangular coil group consists of several right-angled rectangular wires with coincident center points, parallel long sides, and equidistant increasing dimensions.

5. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 2, characterized in that, Each heat dissipation pipe has a baffle plate on its inner wall to allow the coolant inside the heat dissipation pipe to flow in and out.

6. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 2, characterized in that, The outer wall of each heat sink is fitted and fixed to the inner wall of the central hole of the equivalent N-pole coil and the equivalent S-pole coil. The top of each heat sink is fixedly connected to the top plate. An annular heat sink is reserved at the top of each equivalent S-pole coil.

7. The coil configuration of an electrically excited magnetically levitated planar motor as described in claim 1, characterized in that, Both the equivalent N-pole coil and the equivalent S-pole coil are double trapezoidal cross-section rotating bodies. The equivalent N-pole coil has a cross-section configuration in which the short sides of the two trapezoids are connected, and the equivalent S-pole coil has a cross-section configuration in which the long sides of the two trapezoids are connected. The long and short sides of the upper and lower trapezoids of the equivalent N-pole coil and the equivalent S-pole coil are equal, but their heights are unequal.

Images