Laminated planar spiral coil winding

Abstract

The invention relates to the technical field of electromagnetic coils, in particular to a laminated planar spiral coil winding. The laminated planar spiral coil winding is formed by laminating at least two layers of planar spiral coils, the spiral center fitting line formed by each turn of wire is linear, the planar spiral coils occupy the whole winding plane, the strong magnetic center deviates from the geometric center of the planar spiral coils, and the phases of the winding are different in layer. The invention aims to provide competitive choices for the axial flux motor winding, such as high copper full rate, low copper loss, large air gap, easy heat dissipation and low production cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic coil, in particular to a laminated planar spiral coil winding. BACKGROUND

[0002] The motor winding is the core and physical basis of the motor, which is extremely important to the overall significance of the motor and almost determines all key performances of the motor, and can be understood as the combination of the "heart" and "nervous system" of the motor. The motor winding is the physical carrier and executor of electromagnetic energy conversion, directly shapes the core electromagnetic performance (torque, efficiency, noise, back EMF, inductance, etc.) of the motor, determines the key electrical parameters (voltage, current, power, speed, phase number) of the motor, and greatly affects the power density, efficiency and thermal performance of the motor. The traditional axial flux motor usually adopts multiple concentric cylindrical coils to form the winding, or adopts multiple concentric circles, concentric sectors and other coils to form the winding. The common feature of these windings is that the multi-phase winding is uniformly distributed in the same plane, and each winding has different winding copper fullness, copper loss, winding air gap, heat dissipation mode and magnetic performance, each has advantages and disadvantages. The present application innovatively proposes a laminated planar spiral coil winding, which aims to provide a competitive choice for the winding copper fullness, copper loss reduction, air gap increase, heat dissipation improvement, magnetic performance and economic cost of the axial flux motor. SUMMARY

[0003] The purpose of the present application is to provide a competitive choice for the winding copper fullness, copper loss reduction, air gap increase, heat dissipation improvement, magnetic performance and economic cost of the axial flux motor.

[0004] To achieve the above-mentioned purpose, the present application provides the following scheme: A laminated planar spiral coil winding, characterized in that it comprises: 1) composed of at least two layers of planar spiral coil, each layer being a single planar spiral coil covering the entire winding plane; 2) the spiral center fitting line formed by each turn of the planar spiral coil is linear; 3) the strong magnetic centers formed by energizing the same phase windings of each layer project onto a point P in the winding plane, and the point P is offset from the geometric center O of the planar spiral coil; 4) the strong magnetic centers of each phase winding project in the winding plane in a central symmetric distribution after energizing the different layers of each phase winding; 5) the internal gap of the planar spiral coil is provided with magnetic conductive material for improving the magnetic conductive performance of the coil winding, insulating material for improving the insulating performance, heat dissipation material or hole pipe for improving the heat dissipation performance; 6) the output ends of each phase winding are short-circuited to form a squirrel cage equivalent rotor of an axial flux asynchronous motor; 7) The coil winding manufacturing method includes PCB printing or using round / flat wire, lamination wire winding.

[0005] The offset distance D between the projection point P of the strong magnetic center formed after the planar spiral coil is energized and the geometric center of the planar spiral coil satisfies: 0.2R≤D≤0.67R, where R is the spiral outer diameter of the coil.

[0006] The adjacent interval d of the spiral center formed by each turn of the planar spiral wire is equal or gradiently changed.

[0007] The internal gap of the planar spiral coil is filled with amorphous core powder and epoxy resin composite magnetic material or ferrite powder and epoxy resin composite magnetic material, and a micro-channel heat dissipation pipe is embedded to improve the magnetic conductivity, insulation performance and heat conductivity of the coil winding.

[0008] The center-symmetric through-hole heat dissipation hole is arranged at the internal gap of the PCB printed coil winding plane.

[0009] The PCB printed coil winding realizes the interlayer connection of the PCB winding by using through holes.

[0010] The coil winding adopts N-phase power supply topology, and the adjacent phase difference is 360° / N, where N≥2.

[0011] The interlayer connection of the same phase winding sub-coil includes opposite spiral direction series connection, same spiral direction parallel connection, or opposite spiral direction series connection and parallel connection of sub-coils, and the overall winding is preferably connected into a fractional slot winding.

[0012] The coil winding center or interior includes an axial transmission shaft hole or does not include an axial transmission shaft hole.

[0013] A manufacturing method of the winding according to any one of the preceding solutions, characterized by the steps of: (a) laser etching a spiral wire slot on a PCB substrate, with a slot width error ≤±5μm; (b) electroplating to fill the slot to form a wire, with a depth-to-width ratio ≥1.5:1; (c) vacuum pressure infusion of a magnetic conductive composite material, with a pressure of 0.5-0.8MPa; (d) applying an alternating magnetic field with a strength of 50-100mT to directionally arrange amorphous core powder or ferrite particles during lamination; (e) filling the interlayer through hole with conductive paste.

[0014] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0015] The smaller the interval between the spiral centers of each turn of wire of the planar spiral coil, the higher the copper fullness rate of the planar spiral coil, the stronger the generated magnetic field, and the higher the uniformity of the interval between the spiral centers of adjacent turns, and the stronger the uniformity of the magnetic field.

[0016] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0017] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0018] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0019] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0020] The planar spiral coil is a special planar spiral coil, the minimum spiral center of which is not at the geometric center of the planar coil, the connecting line of the spiral centers formed by each turn of wire or the fitting line of the spiral centers is linear, the planar spiral coil is divided into a dense wire area and a sparse wire area as a whole, the minimum spiral of the planar spiral coil is adjacent to the dense wire area, and the maximum spiral center of the planar spiral coil is the geometric center of the planar spiral coil. After the planar spiral coil is electrified, the magnetic lines are asymmetrically distributed, in the dense wire area, due to the high current density and strong coupling effect, a strong magnetic center is formed in the minimum spiral turn area, and other areas outside the strong magnetic center are magnetic field diffusion areas, which is significantly different from the magnetic field mode of the strong magnetic center formed by the traditional cylindrical solenoid and the planar spiral coil.

[0021] Two above-mentioned double-layer planar spiral coils (in series with minimum spiral ports) are symmetrically stacked with the coil center as the center, the maximum spiral ports of the four-layer coil with opposite spiral directions are connected in parallel, one end of the parallel port is used as the current inflow end, and the other end is used as the current outflow end, and the symmetric two minimum spiral centers are the north and south poles of the four-layer coil winding after energization. Three above-mentioned four-layer coils are stacked in three-phase 120°, and then three-phase power is supplied respectively, so as to form an axial magnetic flux rotating magnetic field.

[0022] In the application process of the winding double-face magnetic field as the working surface, the transmission hole can be arranged at the center position of the winding, and the magnetic poles of the two sides of the winding are connected through the transmission pipe, but this may need to adjust the wire at the center position of the winding, which will have a certain influence on the magnetic field, especially for the winding with small diameter and small number of turns, but the benefit of the joint of the double working surfaces is greater.

[0023] The inner space of the planar spiral coil includes the single-layer planar coil inner wire spacing space, the layer spacing space and the space through the whole coil winding (including the wire spacing and layer spacing space), wherein the space through the whole coil winding is usually in a central symmetric state due to the small number of factors of multi-layer stacking. The space of the motor winding is valuable, and in the process of producing the winding by using the traditional wire, the heat dissipation pipe / hole can be arranged in the space through the whole coil winding, then the amorphous core particles or ferrite particles are configured into a filler with epoxy resin glue, the wire spacing space and the layer spacing space in the winding are filled, and the vacuum die casting method is used for integrated die casting, so that the overall magnetic, insulation and heat dissipation of the coil winding are improved. The utilization of the above-mentioned heat dissipation, insulation and magnetic material filling to the inner space of the winding has a synergistic optimization effect on the performance of the winding, and the overall performance of the winding is significantly improved.

[0024] In the production cost of the PCB winding, the blind buried hole is an important part of the PCB production cost, especially for high multi-layer boards. The stacked planar spiral coil winding printed by the PCB has the advantages of realizing the multi-layer coil layer connection by using all through holes, and has a significant economic cost advantage. However, the coil winding of the present application can save more space for the winding by using the blind buried hole in the high multi-layer application, and significantly improve the winding benefit.

[0025] The stacked planar spiral coil winding of the present application adopts N-phase power supply topology, and the phase difference between adjacent phases is 360° / N, wherein N≥2. When N=2, it is consistent with the mode of increasing the capacitance phase modulation of the traditional two-phase motor, and the phase difference is 90°; when N>2, the phase difference between adjacent phases is 360° / N.

[0026] The interlayer connection of the sub-coil of the same phase winding of the present application includes series connection of spiral directions opposite to each other, parallel connection of spiral directions same to each other, or parallel connection of series connected sub-coils with spiral directions opposite to each other. The whole winding is preferably connected into a fractional-slot winding.

[0027] The laminated planar spiral coil winding of the present application can be applied to axial flux motor systems, magnetic suspension systems, sensor systems, magnetic bearing systems, eddy current magnetic coupling systems, magnetic stirring systems, and wireless charging systems.

[0028] Compared with the prior art, the present application has the following advantages and technical effects: 1. The coil winding of the present application is stacked by planar coils, which significantly improves the copper fullness rate of the winding.

[0029] 2. All conductors of the coil winding of the present application participate in the winding of each phase magnetic flux fitting, which significantly improves the magnetic flux utilization rate, reduces the copper loss, and improves the winding efficiency.

[0030] 3. The coil winding of the present application is designed eccentrically, and the strong magnetic field in the dense area of the conductors significantly improves the air gap of the winding.

[0031] 4. In the application of the winding in high multilayer PCB winding, the present application significantly reduces the number of PCB winding drilling holes, and has lower production cost.

[0032] 5. In the traditional winding motor winding, the laminated planar spiral coil winding of the present application can fully utilize the internal space of the winding, increase the insulation material, magnetic material and micro-porous heat dissipation pipe, and the addition of the three can produce a synergistic optimization effect on the winding, which significantly improves the overall performance of the winding.

[0033] 6. The winding coil of the present application has simple structure and is easy to produce in factory, and the winding can be modularized and expanded. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 It is a single-layer planar spiral coil Figure 2 It is a double-layer planar spiral coil Figure 3 It is a double-layer planar spiral coil with a center transmission shaft hole Figure 4 It is a six-layer three-phase coil winding top view Figure 5 It is a twelve-layer PCB coil winding top view Figure 6 It is a twelve-layer PCB coil winding magnetic field simulation plan view Figure 7 It is a twelve-layer PCB coil winding magnetic field simulation sectional view Figure 8 It is a planar spiral coil wound by eight-layer thin copper sheet conductors The figure is marked: 1001, the geometric center point O of the coil winding; 1002, the minimum spiral turn center point P of the coil; 1003, the minimum spiral turn wire end of the coil; 1004, the maximum spiral turn wire end of the coil; 1005, the coil radius R; 1006, the spiral center of each turn of the coil; 1007, the connecting line / fitted line of the spiral center of each turn of the coil; 1008, the counterclockwise spiral coil; 1009, the clockwise spiral coil; 1010, the wire spacing gap of the double-layer planar coil; 1011, the wire avoiding the transmission shaft hole adjustment; 1012, the center transmission shaft hole of the double-layer planar coil; 1013, the PCB coil winding frame; 1014, the interlayer connection through hole in the PCB coil winding; 1015, the symmetrical heat dissipation through hole in the PCB coil winding; and 1016, the wire formed by laminating eight layers of thin copper sheets. DETAILED DESCRIPTION

[0035] The application will be further described in detail below in combination with the drawings and specific preferred embodiments.

[0036] It should be understood that the specific values of the number of laminated layers of the planar spiral coil, the number of laminated layers of the wire, and the number of winding phases in the description of the embodiments of the application are only for illustrating the technical solutions and cannot be understood as limiting the application, nor can they limit the protection scope of the application.

[0037] Embodiment 1: six-layer three-phase coil winding The single-layer planar spiral coil described in the application is as follows Figure 1 1001 is the geometric center point O of the coil winding, 1002 is the minimum spiral turn center point P of the coil, P point is also the strong magnetic center point of the coil after being electrified, the line segment OP is the offset distance D of the strong magnetic center and the geometric center of the spiral coil after being electrified, 1003 is the minimum spiral turn wire end of the coil, 1004 is the maximum spiral turn wire end of the coil, 1005 is the coil radius R, 1006 is the spiral center of each turn of the coil, and the interval between the spiral centers of adjacent two turns is d; and 1007 is the connecting line of the spiral center of each turn of the coil.

[0038] The above Figure 1 The mirror image symmetric setting along the OP line, vertical lamination, and vertical connection of the minimum spiral turn wire end 1003 of the coil form a double-layer planar spiral coil with opposite spiral directions Figure 2 1008 is the counterclockwise spiral coil, 1009 is the clockwise spiral coil, the maximum spiral turn wire end 1004 is respectively on the two sides, and the maximum spiral turn wire end 1004 is respectively taken as the current entering end and the current flowing out end, Figure 2 The double-layer planar spiral coil will generate a same-direction magnetic vector. Figure 1 and Figure 2The left side (from point P to point O) is a sparse area of conductive wires, and the right side is a dense area of conductive wires. The space between the double-layer planar coil wires is shown by 1010, which can be filled with magnetically conductive materials, insulating materials, heat pipes, and holes. Since the double-layer coils are vertically stacked, the double-layer conductive wires in the sparse area of conductive wires appear to be overlapping when viewed from the top.

[0039] Three of the above Figure 2 The double-layer planar spiral coils are vertically stacked, and the strong magnetic center points P of the three double-layer planar spiral coils are adjusted to form six layers of coils with the winding geometric center O as the center, OP as the radius, and an angle difference of 120°. This coil winding is the six-layer three-phase coil winding shown in Figure 4 . Figure 4 The six-layer three-phase coil winding shown in has six coil minimum spiral turn wire ends 1003 that are all internally and vertically connected. The coil maximum spiral turn wire ends 1004 are all exposed. The six wire ends can be connected in a triangular shape or star shape as needed to form a six-layer three-phase coil winding.

[0040] Example 2: Double-layer planar spiral coil with transmission shaft hole Figure 3 The double-layer planar spiral coil shown in has an arc-shaped arrangement of spiral centers for each turn of the coil. The coil is mirror-symmetrically arranged along the OP line, vertically stacked, and has the coil minimum spiral turn wire ends 1003 vertically connected to form a double-layer planar spiral coil with opposite spiral directions. The red spiral center 1006 corresponds to the red small circle, and the corresponding light blue-green spiral center 1006 corresponds to the light blue-green small circle. The OP line is the fitting line 1007 of the spiral centers of each turn of the two coils. The center point O of the double-layer planar spiral coil has a transmission shaft hole 1012 set by adjusting the position of the wire 1011. Both magnetic flux directions of the axial magnetic flux winding can be used as working surfaces. The central transmission shaft hole can uniformly transmit and apply the torque generated by the two working surfaces, which has important practical significance.

[0041] Example 3: Twelve-layer PCB coil winding Figure 2 The double-layer planar spiral coil is provided with a central transmission hole in a wire-avoiding manner. Then, six double-layer planar spiral coils are vertically stacked, and the strong magnetic center points P of the six double-layer planar spiral coils are adjusted to form twelve layers of coils with the winding geometric center O as the center, OP as the radius, and an angle difference of 60°. This coil winding is the twelve-layer PCB coil winding shown in Figure 5 . The interlayer connection of this winding follows the same-phase winding sub-coil interlayer series connection with opposite spiral directions and the same-phase winding sub-coil interlayer parallel connection with the same spiral direction. The interphase connection of this winding uses a triangular connection. Figure 5The middle 1013 is a PCB winding frame, and 1014 is an interlayer connection through hole in the PCB coil winding. The total number of connection through holes of the PCB coil winding is 17, which is much smaller than the number of connection holes required by the centralized PCB winding and the distributed PCB winding, and these windings need to be provided with blind buried holes to meet the connection function of the winding. 1015 is a symmetrical heat dissipation through hole in the PCB coil winding. The hole diameter of the heat dissipation through hole 1015 is determined according to the actual space. The same setting of this embodiment can be applied to 18-layer, 24-layer, 30-layer, and 36-layer PCB coil windings.

[0042] Example 4: Twelve-layer PCB coil winding without heat dissipation through hole The difference between this embodiment and example 3 is that the twelve-layer PCB coil winding of this embodiment does not set the heat dissipation through hole 1015, and the strong magnetic center point P is offset from the geometric center point O with a distance D = 0.6R. Figure 6 The magnetic field simulation plan view of the twelve-layer PCB coil winding is shown in the following figure: Figure 7 The magnetic field simulation profile view of the twelve-layer PCB coil winding is shown in the following figure: Figure 7 The magnetic vector high points on both sides of the coil winding center point O are the edges of the transmission shaft through hole, which may cause magnetic field distortion due to the adjustment of the wire position 1011. Figure 7 At the same time, it also shows that the strong magnetic center point P is located in the smallest spiral area after the plane spiral coil is energized.

[0043] Example 5: Plane spiral coil wound with thin copper sheet The thin copper sheet with insulation is stacked into a strip as a wire, and then wound according to the coil design requirements to form a plane spiral coil. As shown in the following figure: Figure 8 The plane spiral coil wound with eight-layer thin copper sheet is shown in the following figure, and the enlarged view on the right shows that each turn of the coil is a wire 1016 formed by stacking eight-layer thin copper sheets. The stacked plane spiral coil winding made of the plane spiral coil of this embodiment can significantly reduce the influence of current skin effect.

[0044] Example 6: Plane spiral coil wound with flat copper wire The flat copper wire with insulation is used as a wire, and then wound according to the coil design requirements to form a plane spiral coil. The stacked plane spiral coil winding made of the plane spiral coil of this embodiment has a large current characteristic.

[0045] Example 7: Squirrel cage equivalent rotor of axial flux asynchronous motor The short-circuiting of the output ends of the stacked multi-layer multi-phase coil winding made by using the planar coil structure of the present application can form a squirrel cage equivalent rotor of an axial flux asynchronous motor. The equivalent rotor is essentially a magnetic field generated by the current flowing along a specific path generated by the cutting of the magnetic flux by the wire with a specific winding method, and a rotating magnetic field is formed according to the winding phase characteristics. The winding produced in Embodiment 1, Embodiment 3 and Embodiment 6 can form a squirrel cage equivalent rotor after short-circuiting the output ends. In actual design, the performance of the overall squirrel cage equivalent rotor is improved by using magnetic conductive materials, insulating materials and heat dissipation pipes or hole filling technology, focusing on the current carrying capacity. In practical applications, the squirrel cage equivalent rotor winding can not only be used as a rotor of an axial flux asynchronous motor, but also can replace the eddy current plate to form a more concentrated and controllable eddy current magnetic field.

[0046] Embodiment 8: Manufacturing the PCB coil winding of the present application by laser etching 1) Line slot etching: On the basis of mechanical positioning and template calibration, a fiber nanosecond laser machine is used to etch the planar spiral coil structure described in the present application on the PCB substrate; 2) Electroplating slot filling a. Chemical copper plating on etched line slot using acidic copper sulfate system; b. Air stirring and moving cathode electroplating method; c. Chemical mechanical polishing to remove the surface overflow copper layer.

[0047] 3) Vacuum negative pressure perfusion of magnetic conductive material, stepwise temperature rise and solidification; 4) Alternating magnetic field directional arrangement of magnetic conductive material Pre-pressing (80℃, 30min) → placed in a rotatable variable magnetic field → gel period (100℃, 60min, change magnetic pole every 10min) → remove the magnetic field → full curing (130℃, 120min) 5) Silver-coated copper paste is used to fill the interlayer through-hole.

[0048] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A layered planar helical coil winding, characterized in that, include: 1) It consists of at least two layers of planar spiral coils stacked together, each layer being a single planar spiral coil covering the entire winding; 2) The fitting line of the spiral center formed by each turn of the conductor in the planar spiral coil is linear; 3) The strong magnetic center formed by each layer of in-phase winding after being energized coincides with a point P in the plane of the coil winding, and point P is offset from the geometric center O of the planar helical coil. 4) The windings are in different layers for each phase, and after each phase winding is energized, the strong magnetic center is projected onto the plane of the coil winding in a centrally symmetrical distribution; 5) The internal gaps of the planar helical coil are filled with magnetic materials to improve the magnetic permeability of the coil winding, insulating materials to improve the insulation performance, and heat dissipation materials or perforations to improve the thermal conductivity. 6) Short-circuit the output terminals of each phase winding to form the squirrel-cage equivalent rotor of the axial flux asynchronous motor; 7) Coil winding manufacturing methods include using PCB printing or using round / flat wires or laminated wires for winding.

2. The coil winding according to claim 1, characterized in that... The offset distance D between the projection point P of the strong magnetic center formed by the planar helical coil after it is energized and the geometric center of the planar helical coil satisfies: 0.2R≤D≤0.67R, where R is the outer diameter of the coil helix.

3. The coil winding according to claim 1, characterized in that... In a planar helix, the spacing d between adjacent spiral centers formed by each turn of the conductor is equal or varies with gradient.

4. The coil winding according to claim 1, characterized in that... The internal gaps of the planar spiral coil are filled with a composite magnetic material of amorphous iron core powder and epoxy resin or a composite magnetic material of ferrite powder and epoxy resin, and a microchannel heat dissipation tube is embedded to improve the magnetic permeability, insulation performance and thermal conductivity of the coil winding.

5. The coil winding according to claim 1, characterized in that... The PCB printed coil winding plane has centrally symmetrical through-holes for heat dissipation.

6. The coil winding according to claim 1, characterized in that... The coil windings printed on the PCB are connected between PCB winding layers using through holes.

7. The coil winding according to claim 1, characterized in that... The coil winding adopts an N-phase power supply topology with an adjacent phase difference of 360° / N, where N≥2.

8. The coil winding according to claim 1, characterized in that... Interlayer connections of in-phase winding sub-coils include series connection with opposite helical directions, parallel connection with the same helical direction, or parallel connection of series sub-coils with opposite helical directions, and the overall winding is connected as a fractional-slot winding.

9. The coil winding according to claim 1, characterized in that... The coil winding center or interior may or may not have an axial drive shaft hole.

10. A method for manufacturing a winding according to any one of claims 1 to 9, characterized in that... step: (a) Laser etching of spiral grooves on PCB substrate, with groove width error ≤ ±5μm; (b) Electroplating filler formed wires with a depth-to-width ratio ≥ 1.5:1; (c) Vacuum pressure infusion of magnetically conductive composite material, pressure 0.5-0.8 MPa; (d) Applying an alternating magnetic field with an intensity of 50-100mT during lamination to oriented amorphous iron core powder or ferrite particles; (e) Use conductive paste to fill the interlayer vias.

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