A permanent magnet brushless DC motor with printed winding

Abstract

The present invention discloses a permanent magnet brushless DC motor using a novel printed winding system. The motor comprises a stator constructed from a multi-layer printed circuit board and an axially magnetized permanent magnet rotor. Each phase of the stator winding utilizes a quadrilateral printed winding scheme, significantly reducing the motor's axial dimensions and manufacturing costs. Compared to conventional printed motors, the quadrilateral printed winding scheme employed in the present invention eliminates dead windings at the ends, improving motor efficiency and reducing motor temperature rise. Furthermore, the back EMF waveform is sinusoidal, facilitating vector control of the motor.

Description

Technical Field

[0001] The present invention belongs to the technical field related to motor design, and in particular relates to a permanent magnet brushless DC motor with printed windings. Background Art

[0002] Traditional permanent magnet brushless DC motors are mostly radial magnetic field motors, and the stators are composed of coils and iron cores. The motors are large and bulky. The complex offline process leads to complex motor manufacturing process, long production cycle, high material consumption and high cost.

[0003] The windings of printed-winding motors differ from the coil windings of traditional motors. They are printed on copper foil using chemical methods such as etching, electrochemical deposition, and electrochemical transfer. Permanent magnet brushless DC motors with printed windings break through the limitations of traditional motors in terms of structural design. The motors utilize an axial magnetic field, eliminating the need for a traditional stator core. This significantly reduces the size and weight of the motors, while improving their operating efficiency and overload capacity. Furthermore, they enable remote intelligent control. Furthermore, the motor production process does not involve the winding of the stator winding, resulting in lower production costs than traditional brushless DC motors. Consequently, their overall performance surpasses that of traditional motors.

[0004] The operating principle of a printed-winding permanent magnet brushless DC motor is the same as that of a traditional permanent magnet brushless DC motor. Its characteristics include high starting torque, a wide speed regulation range, and high operating efficiency. A key design feature of a printed-winding permanent magnet brushless DC motor is the connection method for the stator printed circuit board (PCB) windings. While patent document CN104659993A describes a PCB winding connection method, this PCB stator uses a concentric winding connection method. The conductors of this concentric winding are connected using arc-shaped end wires. This has the disadvantages of high copper consumption, lack of torque output, increased motor losses, and increased motor temperature rise. Other literature also proposes a wave winding arrangement for the PCB windings, but this still requires the use of arc-shaped end wires to connect the conductors. Furthermore, stator PCBs using concentric and wave windings exhibit a square-wave back-EMF waveform, which cannot achieve the superior sinusoidal control performance of the motor controller. Summary of the Invention

[0005] The purpose of the present invention is to address the above-mentioned technical problems existing in the prior art. The present invention provides a printed winding design scheme based on quadrilateral conductors, which can reduce the volume and manufacturing cost of permanent magnet brushless DC motors and improve operating efficiency. In addition, the back electromotive force waveform can be designed as a sine wave, which facilitates the implementation of high-performance vector control and improves the performance and working efficiency of the motor.

[0006] In order to solve the above problems, the present invention provides the following technical solutions:

[0007] A permanent magnet brushless DC motor with printed windings comprises a motor housing, a stator fixedly disposed within the motor housing, and a rotor assembly rotatably disposed through the motor housing; the stator is a printed circuit board structure comprising a working conductor layer and a connecting conductor layer; the winding units in the working conductor layer are arranged in a quadrilateral shape, and each phase winding of each pole of the stator is formed by connecting a plurality of quadrilateral winding units in series. The windings of each phase with different pole numbers are connected in series or in parallel via the connecting conductor layer to form a single phase winding.

[0008] Preferably, there are two working conductor layers, and the two working conductor edges of the quadrilateral winding unit in the left L shape are located on one of the working conductor layers, and the two working conductor edges of the quadrilateral winding unit in the right L shape are located on the other working conductor layer. The outer ends of the two working conductor edges of the left L shape and the two working conductor edges of the right L shape are connected in series through outer diameter vias, and the inner ends are connected in series through inner diameter vias, thereby forming a quadrilateral winding unit. This winding structure only requires two working conductor layers to print the windings of each pole and phase on a printed circuit board, which can reduce the thickness of the stator, simplify the processing technology, and reduce manufacturing costs. Among them, the distance between the intersection of the two working conductor edges in the left L shape and the intersection of the two working conductor edges in the right L shape in the quadrilateral winding unit is not greater than the pole pitch of the motor, which is conducive to realizing sinusoidal wave control of the motor controller and is convenient for controlling the motor using vector control.

[0009] Furthermore, the connecting conductor layer includes a plurality of connecting conductor edges, and each pole and each phase winding of the stator includes a positive terminal and a negative terminal, and the negative terminal of each pole and each phase winding is electrically connected to the positive terminal of the adjacent pole winding of the phase through the connecting conductor edge; in this scheme, each pole and each phase winding is connected in series, that is, the number of parallel branches per phase is 1. The above winding configuration method is one of the schemes, and the number of parallel branches per phase can also be greater than 1. Other winding connection configuration schemes are also within the scope of protection of the patent.

[0010] The stator also includes a plurality of via-hole conductor posts perpendicular to the working conductor layer and the connecting conductor layer. The via-hole conductor posts are used for the electrical connection between the two working conductor sides in the left L shape and the two working conductor sides in the right L shape of the quadrilateral winding unit, and for the electrical connection between the positive terminal and / or negative terminal of each pole and each phase winding and the connecting conductor side.

[0011] Preferably, a Hall position sensor is also provided on the printed circuit board of the stator. Of course, the Hall position sensor may not be used. The stator can be powered by direct current or alternating current. The stator includes three-phase windings, and the three-phase windings have the same connection structure. When the three-phase windings are combined, they are spatially offset by 120 electrical degrees. There are three Hall position sensors, which are respectively installed at the center line position of each phase winding.

[0012] In which, the stator is formed by stacking multiple working conductor layers and multiple connecting conductor layers, each working conductor layer and each connecting conductor layer is a flat structure, and there is an insulating substrate layer between each layer; the rotor assembly includes a drive shaft and a first rotor and a second rotor fixed on the drive shaft, a central circular hole is provided in the middle of the stator for the drive shaft to pass through, and the first rotor and the second rotor are respectively located on both sides of the stator; the first rotor and the second rotor both include a rotor back iron and a fan-shaped permanent magnet array, and the number of permanent magnets contained in the permanent magnet array is an even number and at least two.

[0013] The rotor back iron is made of laminated silicon steel sheets or a single piece of magnetically conductive material. The permanent magnet material can be ferrite, samarium cobalt, neodymium iron boron, or a combination of these three materials. The permanent magnets are surface-mounted or embedded in the rotor back iron. The permanent magnets of the first rotor are arranged relative to the permanent magnets of the second rotor so that the magnetic flux lines pass through the stator in a direction perpendicular to the stator plane, and the north and south poles of adjacent permanent magnets are staggered, i.e., they form an NS-SN distribution.

[0014] The stator and rotor assembly can be configured as an outer stator / inner rotor or outer rotor / inner stator structure, or as a single stator / single rotor, single stator / dual rotor, dual stators / single rotor, dual stators / triple rotor, or triple stators / dual rotor structure. The motor can be used for pure power generation, pure electric motoring, or a combination of power generation and electric motoring.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] The present invention discloses a permanent magnet brushless DC motor with a printed winding structure, in which each phase winding of the stator adopts a quadrilateral printed winding scheme. This printed winding greatly reduces the axial size and production cost of the motor. Compared with the stator with traditional arc-shaped end-line printed windings, the present invention eliminates the ineffective end windings, reduces copper consumption, and reduces the temperature rise of the motor. Moreover, its back electromotive force waveform is a sine wave, which facilitates the use of vector control to control the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is an assembly diagram of one embodiment of the permanent magnet brushless DC motor with a printed winding structure according to the present invention;

[0018] Figure 2 is a three-dimensional perspective view of the stator printed winding shown;

[0019] Figure 3 yes Figure 2 A view of the stator is shown with one phase winding omitted;

[0020] Figure 4 yes Figure 2A view of the stator is shown with two phase windings omitted;

[0021] Figure 5 is a plan view of the stator printed winding shown;

[0022] Figure 6 This is the preferred arrangement of the stator printed windings shown. DETAILED DESCRIPTION

[0023] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings and examples:

[0024] Figure 1 The embodiment of the present invention is shown in FIG. The permanent magnet brushless DC motor with a printed winding structure includes two motor housings 1 and 7 , a drive shaft 5 , two rotor back irons 4 and 6 , two sets of axially magnetized sector-shaped permanent magnet arrays 3 and 8 , a printed circuit board stator 2 , and a bearing 9 .

[0025] Still refer to Figure 1 The permanent magnet arrays 3 and 8 each contain four permanent magnets, each magnetized axially. The permanent magnet material can be ferrite, samarium cobalt, neodymium iron boron, or a combination of the above three materials. The permanent magnet arrays 3 and 8 can be fixed to the rotor back iron 4 and 6 respectively by surface mounting or embedding. In this embodiment, the permanent magnet arrays 3 and 8 are embedded in the rotor back iron 4 and 6. The permanent magnet array 3 and the rotor back iron 4 constitute the first rotor, and the permanent magnet array 8 and the rotor back iron 6 constitute the second rotor. The permanent magnets of the first rotor are arranged relative to the permanent magnets of the second rotor so that the magnetic flux lines pass through the stator in a direction perpendicular to the flat structure of the stator printed circuit board. The north and south poles of adjacent permanent magnets are staggered, that is, in an NS-SN distribution. Of course, the permanent magnet arrays 3 and 8 can also be configured with other numbers of poles, such as two, six, eight, sixteen, or any other even number of poles that can be manufactured.

[0026] The first rotor and the second rotor are assembled together through a drive shaft 5 , and both ends of the drive shaft are fixed to the two motor housings 1 and 7 through bearings 9 .

[0027] Combine Figure 1 and Figure 2A three-dimensional image of the stator printed winding. The stator printed circuit board 2 is a sheet-like, multi-layer structure with an octagonal outer edge. It can also adopt circular, square, or other shapes suitable for specific applications. The stator printed circuit board 2 has five layers, but other configurations, such as 2, 4, or 6 layers, or any integer number of layers, are also possible. In this preferred embodiment, the top two layers are working conductor layers. The windings of the first layer consist of two working conductor edges in a "<" shape (left L-shape) within the quadrilateral winding unit, and the second layer consists of two working conductor edges in a ">" shape (right L-shape) within the quadrilateral winding unit. The upper and lower working conductor layers are electrically connected via vias located on the inner and outer diameters (inner diameter vias and outer diameter vias). The distance between the intersection of the left and right L-shaped conductors is no greater than the motor's pole pitch. In this preferred embodiment, the distance between the intersection of the left and right L-shaped conductor edges is an integer pole pitch, i.e., equal to the motor's pole pitch. The third, fourth, and fifth layers are connecting conductor layers. The negative terminal of each pole and phase quadrilateral winding is electrically connected to the positive terminal of the quadrilateral winding of the adjacent pole via the connecting conductor edges of the third, fourth, and fifth layers. This means that each pole and phase quadrilateral winding conductor is connected in series, with one parallel branch. There are 48 quadrilateral coils in total, forming a three-phase, four-pole system. The above winding connection method, number, and pole pair number selection are only one preferred embodiment; other winding connection methods, numbers, and pole pair number selections are also within the scope of protection of the patent.

[0028] Figure 2 A three-phase stator printed winding is shown in a perspective view. 1A, 1B, and 1C represent the left L-shaped working conductor side of the first working conductor layer, phases A, B, and C. 2A, 2B, and 2C represent the right L-shaped working conductor side of the second working conductor layer, phases A, B, and C. 11 represents the connecting conductor side of the printed winding located in the connecting conductor layers, i.e., the third, fourth, and fifth layers, which connect the negative and positive terminals of each pole and phase. Electrical connections are made between the first and second working layer conductors, and between the working layer conductors and the connecting layer conductors, via conductor posts 10.

[0029] Figure 3 It shows the arrangement of the B and C phase windings after phase A is removed, where 1B and 1C are the left L-shaped working conductor sides of phases B and C of the first working conductor layer, 2B and 2C are the right L-shaped working conductor sides of phases B and C of the second working conductor layer, 10 is a via conductor column, and 11 is a connecting conductor side in the connecting conductor layer.

[0030] Figure 4 The diagram shows the layout of the C-phase winding after phases A and B are removed. 1C is the left L-shaped C-phase working conductor edge of the first working conductor layer, 2C is the right L-shaped C-phase working conductor edge of the second working conductor layer, 10 is a via conductor, and 11 is a connecting conductor edge in the connecting conductor layer. The connecting conductor edge 11 does not necessarily need to be arranged as shown; it can be optimized based on principles such as copper conservation and drawing convenience.

[0031] Figure 5 A plan view of the printed stator windings is shown, illustrating the winding configuration from another perspective. α, β, and γ represent the effective conductors that cut through the magnetic field of the three-phase quadrilateral windings A, B, and C. 11A, 11B, and 11C represent the connecting conductor edges, or end conductors, within the three-phase quadrilateral windings A, B, and C. If Hall effect position sensors are required on the stator plate, they can be installed at the centerline of each of the three adjacent phase windings. In this preferred embodiment, the three position sensors are placed at the dashed lines indicated by X, Y, and Z.

[0032] Figure 6 A preferred arrangement scheme for the stator printed winding is shown. The figure only shows the distribution of one-phase winding, which has four working conductor layers. The conductors at the same position in different working conductor layers are connected in parallel through vias. 1D represents the left L-shaped conductor side of the first working conductor layer, and 2D represents the right L-shaped conductor side of the second working conductor layer, which forms a quadrilateral conductor coil with the L-shaped conductor side at the corresponding position of 1D. 3D represents the left L-shaped conductor side of the third working conductor layer, and 4D represents the right L-shaped conductor side of the fourth working conductor layer, which forms a quadrilateral conductor coil with the L-shaped conductor at the corresponding position of 2D. The quadrilateral conductors formed by the first and second working conductor layers are connected in parallel with the quadrilateral conductors at the same position in the third and fourth working conductor layers through vias at both ends to increase the current value passing through the stator. 11 represents the connecting conductor side of the connecting conductor layer, that is, the end conductor, and 10 is the via conductor column.

[0033] The above description is merely a preferred embodiment of the present invention and does not limit the technical scope of the present invention. Therefore, any minor modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A permanent magnet brushless DC motor with printed windings, comprising a motor housing, a stator fixedly disposed within the motor housing, and a rotor assembly rotatably disposed through the motor housing; the stator being a printed circuit board structure including a working conductor layer and a connecting conductor layer; characterized in that: The winding units in the working conductor layer are arranged in a quadrilateral. Each phase winding of each pole of the stator is composed of multiple quadrilateral winding units connected in series. Each phase winding with different pole numbers is connected in series or in parallel through the connecting conductor layer to form a phase winding. There are two working conductor layers, the two working conductor sides of the quadrilateral winding unit in the left L shape are located on one of the working conductor layers, and the two working conductor sides of the quadrilateral winding unit in the right L shape are located on the other working conductor layer, the distance between the intersection of the two working conductor sides in the left L shape and the intersection of the two working conductor sides in the right L shape in the quadrilateral winding unit is no greater than the pole pitch of the motor, the left L shape is a "<" shape, and the right L shape is a ">" shape; The connecting conductor layer includes a plurality of connecting conductor edges, each pole and each phase winding of the stator includes a positive terminal and a negative terminal, and the negative terminal of each pole and each phase winding is electrically connected to the positive terminal of the adjacent pole winding through the connecting conductor edges; The stator further comprises a plurality of via-hole conductor posts perpendicular to the working conductor layer and the connecting conductor layer, the via-hole conductor posts being used for electrical connection between the two working conductor sides of the left L-shape and the two working conductor sides of the right L-shape of the quadrilateral winding unit, and for electrical connection between the positive terminal and / or negative terminal of each pole and each phase winding and the connecting conductor side; The rotor assembly includes a drive shaft and a first rotor and a second rotor fixed on the drive shaft. Both ends of the drive shaft are fixed to the motor housing through bearings.

2. The permanent magnet brushless DC motor with printed windings according to claim 1, characterized in that: A Hall position sensor is also provided on the printed circuit board of the stator.

3. The permanent magnet brushless DC motor with printed winding according to claim 1 or 2, characterized in that: The stator includes three-phase windings, the three-phase windings have the same connection structure, and when the three-phase windings are combined, they are spaced 120 electrical degrees apart from each other.

4. The permanent magnet brushless DC motor with printed windings according to claim 1, characterized in that: The stator is formed by stacking multiple working conductor layers and multiple connecting conductor layers. Each working conductor layer and each connecting conductor layer is a flat structure, and an insulating substrate layer is provided between each layer. A central circular hole is provided in the middle of the stator for the drive shaft to pass through, and the first rotor and the second rotor are respectively located on both sides of the stator; The first rotor and the second rotor both include a rotor back iron and a sector-shaped permanent magnet array. The number of permanent magnets included in the permanent magnet array is an even number and is at least two.

5. The permanent magnet brushless DC motor with printed windings according to claim 4, characterized in that: The rotor back iron is made of laminated silicon steel sheets or a whole piece of magnetically conductive material. The permanent magnet material can be ferrite, samarium cobalt, neodymium iron boron or a combination of the above three materials. The permanent magnet is surface-mounted or embedded on the rotor back iron.

6. The permanent magnet brushless DC motor with printed windings according to claim 4, characterized in that: The permanent magnets of the first rotor are arranged relative to the permanent magnets of the second rotor such that magnetic flux lines pass through the stator in a direction perpendicular to the stator plane, and the N poles and S poles of adjacent permanent magnets are alternately distributed.

7. The permanent magnet brushless DC motor with printed windings according to claim 4, characterized in that: The stator and rotor assembly can be configured as an outer stator / inner rotor or outer rotor / inner stator structure, or as a single stator / single rotor, single stator / double rotor, double stators / single rotor, double stators / three rotors, or three stators / double rotor structure.

8. The permanent magnet brushless DC motor with printed windings according to claim 1, characterized in that: The motor can be used for pure generator, pure electric motor or combined generator-electric motor operation.

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