Stator, flat wire motor, powertrain and vehicle

Abstract

The present application relates to the technical field of motor windings, and specifically to a stator, a flat wire motor, a powertrain and a vehicle, so that the fundamental wave winding coefficient is high and the harmonic winding coefficient is low. The stator includes a stator core and a stator winding, and the inner wall of the stator core is evenly provided with a plurality of stator slots in the circumferential direction. The stator winding includes a flat wire conductor inserted in the stator slot, and N layers of flat wire conductors are provided in any stator slot, wherein N is an even number greater than or equal to 4; each flat wire conductor is connected to form an m-phase winding, and each phase winding includes a plurality of phase units evenly and spaced along the circumference of the stator core, and any phase unit of each phase winding includes at least two phase belts, and each phase belt of any phase unit includes two adjacent layers of flat wire conductors, and the adjacent phase belts of any phase unit are offset by one stator slot. The stator winding is a short-distance winding, and thus has a good torque fluctuation suppression effect when the motor is running, reduces the back electromotive force harmonics of the motor, and improves the performance of the motor.

Description

Technical Field

[0001] The present application relates to the technical field of motor windings, and particularly relates to a stator, a flat wire motor, a powertrain, and a vehicle. Background Art

[0002] Due to the high copper fill factor, the flat wire motor is beneficial to the heat dissipation of the motor winding, can improve the withstand voltage capacity of the winding, and reduce the length of the winding end, etc. Therefore, it can improve the torque density and power density of the motor. Thus, the flat wire motor has become an important measure to promote the lightweight of automobiles, increase the cruising range of electric vehicles, improve the space utilization rate of automobiles, and reduce the cost of the powertrain.

[0003] Currently, the winding method of the existing flat wire motor stator winding is mostly full pitch winding. Specifically, the motor includes a stator core, and stator slots are provided in the circumferential direction of the stator core. The stator winding is wound around the stator core through the stator slots. Among them, the flat wire motor with a full pitch structure has a high harmonic winding coefficient, and the torque fluctuation is large during operation, which deteriorates the noise, vibration, and harshness (NVH) of the motor and reduces the performance of the motor. The existing method can set the stator winding as a short pitch winding to reduce the harmonic winding coefficient of the flat wire motor, thereby improving the NVH performance of the electric vehicle. However, for the short pitch winding of the existing flat wire motor, the short pitch setting method is limited by the winding form, and it is difficult to effectively weaken the harmonic winding coefficient while obtaining a high fundamental wave winding coefficient, reducing the performance of the motor. Summary of the Invention

[0004] The present application provides a stator, a flat wire motor, a powertrain, and a vehicle, and provides a flat wire short pitch winding structure that can effectively weaken the harmonic winding coefficient on the basis of ensuring a high fundamental wave winding coefficient, thereby improving the performance of the motor.

[0005] In a first aspect, the present application provides a stator of a flat wire motor. The stator includes a stator core and a stator winding. A plurality of stator slots are evenly provided in the circumferential direction of the inner wall of the stator core. The stator winding includes flat wire conductors inserted into the stator slots. There are N layers of flat wire conductors in any stator slot, where N is an even number greater than or equal to 4. Each flat wire conductor is connected to form an m-phase winding. Each phase winding includes a plurality of phase units evenly and spaced along the circumferential direction of the stator core. Any phase unit of each phase winding includes at least two phase bands. Each phase band of any phase unit includes adjacent two layers of flat wire conductors. The adjacent phase bands of any phase unit are staggered by one stator slot.

[0006] The stator of the present application includes a stator core and a stator winding. The stator core is provided with a plurality of stator slots for arranging flat wire conductors, and N layers of flat wire conductors are arranged in any stator slot. Each flat wire conductor is connected to form an m-phase winding. Each phase winding includes a plurality of phase units, and the phase units are evenly and spaced along the circumferential direction of the stator core. Among them, in any phase unit of each phase winding, two adjacent layers of flat wire conductors form a phase belt, and there is a dislocation of one stator slot between adjacent phase belts. This setting structure can make the equivalent pitch of the obtained flat wire motor less than the pole pitch of the flat wire motor, and the obtained stator winding is a short-pitch winding. After testing, the flat wire motor with this structure can have a relatively high fundamental winding coefficient to improve the output performance of the flat wire motor. At the same time, the flat wire motor with this structure also has a relatively low harmonic winding coefficient, thereby suppressing the torque ripple of the flat wire motor, reducing the back electromotive force harmonics, and improving the comprehensive output performance of the flat wire motor. Applying the flat wire motor with the above performance to an electric vehicle can effectively improve the running smoothness of the electric vehicle and improve the unevenness of the electric vehicle.

[0007] In addition, in the stator of the present application, each phase belt of any phase unit only includes two adjacent layers of flat wire conductors, which can simplify the types of wire shapes of the stator winding, make the twisting directions of the stator winding at the welding ends consistent, and thus simplify the processing difficulty and facilitate connection.

[0008] In a possible implementation manner of the present application, there is a dislocation of one stator slot between adjacent phase belts of any phase unit in the clockwise direction or in the counterclockwise direction. In this implementation manner, there is a dislocation in the same direction between adjacent phase belts within the same phase unit. In a possible implementation manner of the present application, there is a dislocation of one stator slot between adjacent phase belts of any phase unit in the clockwise direction and in the counterclockwise direction. In this implementation manner, the adjacent phase belts within the same phase unit can be alternately in the clockwise and counterclockwise directions, or first have a clockwise dislocation and then a counterclockwise dislocation, or first have a counterclockwise dislocation and then a clockwise dislocation. In an optional implementation manner, when there is a dislocation of one stator slot between adjacent phase belts of any phase unit in the clockwise direction and in the counterclockwise direction, any of the phase units is symmetrically arranged along the perpendicular bisector of the axis direction of the stator core. Among them, in the present application, the direction of the number of dislocated slots between adjacent phase belts is not limited and can be freely combined, with a wider application range.

[0009] In a possible implementation manner of the present application, each phase winding is divided into N / 2 parts along the axis direction of the stator core. In each part, two adjacent layers of flat wire conductors are connected to form a coil layer, and each part includes two coil layers. In a possible implementation manner of the present application, between adjacent coil layers in each phase winding, they are connected by a single cross wire, that is, the cross-layer connection is realized by a single cross wire, which helps to simplify the flat wire winding structure and is easy to implement.

[0010] In a possible implementation manner of the present application, the two opposite sides of the stator winding along the axial direction of the stator core are respectively the wire insertion end and the welding end. On the welding end side, the span of a single cross wire between different coil layers is equal, so that the turning angles of the welding end are the same, thereby simplifying the turning and welding processes and contributing to the simplification of the manufacturing process of the stator winding.

[0011] In a possible implementation manner of the present application, a plurality of flat wire conductors can be arranged on the stator slots in the same direction, so that the turning angles of the stator winding at the welding end are kept consistent, thereby avoiding problems such as complex turning and welding caused by inconsistent turning angles at the welding end, further effectively simplifying the design of the stator winding and facilitating implementation.

[0012] In a possible implementation manner of the present application, each phase winding includes at least one branch, that is, each phase winding can include one branch, two parallel branches, three parallel branches or multiple parallel branches. When each phase winding includes at least two branches, each of the parallel branches includes flat wire conductors of different layers distributed in the same-layer phase belts of adjacent phase units, and each of the flat wire conductors in the same phase belt is evenly distributed in different parallel branches. In this way, the potential balance can be maintained between the parallel branches of each phase winding, and the generation of circulating current between the branches can be avoided.

[0013] In a possible implementation manner of the present application, the stator winding can be a three-phase winding, and the three-phase winding includes a U-phase winding, a V-phase winding and a W-phase winding.

[0014] Among them, the number of stator slots opened on the inner wall of the stator core is Z, the number of phases of the stator winding is m, the number of poles of the stator winding is 2p, and p is an integer. The number of stator slots per pole per phase is q, and the relationship among Z, m, 2p and q satisfies: q = Z / 2pm. In a possible implementation manner of the present application, the number Z of stator slots can be 48 or 54. In a possible implementation manner of the present application, the number of layers of flat wire conductors can be 6 or 10. In a possible implementation manner of the present application, the number of poles 2p of flat wire conductors can be 6 or 8.

[0015] In a second aspect, the present application provides a flat wire motor, which includes a rotor and the stator of the first aspect of the present application. The rotor is arranged in the space surrounded by the inner wall of the stator core.

[0016] Since the stator of the present application can have a lower harmonic winding coefficient on the basis of a relatively high fundamental wave winding coefficient, the flat wire motor including the stator of the present application can have the characteristics of small vibration, low noise, small stray loss and low temperature rise.

[0017] In a third aspect, the present application provides a powertrain, which includes a reducer and the flat wire motor of the second aspect of the present application, and the flat wire motor is drivingly connected to the reducer.

[0018] In a fourth aspect, the present application provides a vehicle, which includes the powertrain as in the third aspect of the present application.

[0019] The technical effects that can be achieved in the above third and fourth aspects can be referred to the corresponding effect descriptions in the above first aspect, and will not be repeated here. Description of the Drawings

[0020] Figure 1 It is the phase belt distribution diagram of a traditional short-pitch winding with a pitch of 8;

[0021] Figure 2 It is the phase belt distribution diagram of a traditional short-pitch winding with a pitch of 7;

[0022] Figure 3 It is the three-dimensional structure schematic diagram of the stator of the flat wire motor according to an embodiment of the present application;

[0023] Figure 4 It is the front view structure schematic diagram of the stator of the flat wire motor according to an embodiment of the present application;

[0024] Figure 5 It is the top view structure schematic diagram of the stator core according to an embodiment of the present application;

[0025] Figure 6 It is the structure schematic diagram of the hairpin coil according to an embodiment of the present application;

[0026] Figure 7 It is the top view structure schematic diagram of the flat wire conductor inserted into the stator slot according to an embodiment of the present application;

[0027] Figure 8 It is the phase belt distribution diagram of the U-phase winding according to an embodiment of the present application;

[0028] Figure 9 It is the phase belt distribution diagram of the U-phase winding according to another embodiment of the present application;

[0029] Figure 10 It is Figure 8 The single-branch expansion diagram of the U-phase winding in

[0030] Figure 11 It is the connection structure schematic diagram of a branch 2;

[0031] Figure 12 It is Figure 11 The enlarged connection structure schematic diagram of some flat wire conductors in

[0032] Figure 13Schematic diagram of the structure of the motor stator core and the U-phase winding in an embodiment of the present application;

[0033] Figure 14 Schematic diagram of the structure of the motor stator core and the U-phase winding in an embodiment of the present application;

[0034] Figure 15 Comparison diagram of torque fluctuations at the peak torque operating points of the windings, full-pitch windings, and traditional short-pitch winding motors in Embodiment 1.

[0035] Reference numerals:

[0036] 10 - Stator core; 10a - Insertion end; 10b - Extraction end; 11 - Stator slot; 20 - Stator winding; 20a - Wiring end;

[0037] 20b - Welding end; 21 - Flat wire conductor; 22 - Hairpin coil; 221 - Leg; 222 - Connection part; 223 - Bending part. Detailed implementation manners

[0038] In order to make the objectives, technical solutions, and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings.

[0039] The terms used in the following embodiments are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in the specification and appended claims of the present application, the singular forms "a", "an", "the", "above-mentioned", "said", and "this" are also intended to include, for example, the expression "one or more", unless there is a clear indication to the contrary in the context.

[0040] References to "one embodiment" or "some embodiments" or the like described in this specification mean that specific features, structures, or characteristics described in connection with that embodiment are included in one or more embodiments of the present application. Thus, the statements "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification are not necessarily all referring to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0041] At present, the drive motors of new energy vehicles mainly use permanent magnet synchronous motors. In permanent magnet synchronous motors, the motor stator can be divided into round wire conductors and flat copper wire conductors according to the cross-sectional shape of the stator winding. The motor using flat copper wire conductors is called a flat wire motor. The flat wire motor can effectively improve the slot fill factor, power density and torque density. With the rapid development of the new energy vehicle industry, the requirements for the number of layers, parallel branch numbers and winding forms of flat wire motors are getting higher and higher. The multi-layer and multi-branch solutions are beneficial to reducing the eddy current loss of flat wires, improving the efficiency of the motor during high-speed operation, and at the same time increasing the diversity of the series turns of the winding, which is of great benefit to the motor performance. However, with the increase in the structural forms of the stator winding, especially the short-pitch winding with balanced multi-branches, the structure is more complex and the implementation difficulty increases; referring to Figure 1 and Figure 2 , the existing stator winding structures with short-pitch structures are limited by the winding connection forms and are difficult to take into account both the high fundamental winding coefficient and the low harmonic winding coefficient, resulting in higher additional losses, lower efficiency, and greater vibration and noise of the flat wire motor. To solve the above problems, the embodiments of the present application provide a flat wire motor stator.

[0042] For easy understanding, the following first explains the professional terms appearing in the present application as follows.

[0043] Stator: It refers to the stationary part of the motor, and its function is to generate a rotating magnetic field.

[0044] Rotor: It refers to the rotating part in the motor, and its function is to realize the conversion between electrical energy and mechanical energy.

[0045] Number of poles: That is, the number of magnetic poles of the motor. The magnetic poles are divided into N poles and S poles. Generally, 1 N pole and 1 S pole are called a pair of magnetic poles, that is, the number of pole pairs is 1. Therefore, if the number of pole pairs of the motor is 1, 2, 3, 4, the number of poles of the motor is 2, 4, 6, 8.

[0046] Pole pitch: The pole pitch of the winding refers to the distance occupied by each magnetic pole on the circumferential surface. For an AC motor, it refers to the slot pitch occupied by each magnetic pole along the inner circle of the stator core. Expressed in terms of the number of slots, the pole pitch f is equal to the ratio of the number of stator slots Z to the number of magnetic poles 2p, that is, f = z / 2p.

[0047] Pitch: It refers to the number of slots occupied by the two effective sides of a single coil. For example, the pitch y = 6, that is, the two effective sides of the coil are separated by 6 slots, which means that the two effective sides are respectively inserted into the 1st slot and the 7th slot.

[0048] Number of slots per pole per phase q: The number of slots occupied by each phase winding under each magnetic pole is called the number of slots per pole per phase.

[0049] In addition, the winding method of the stator winding includes a full-pitch winding and a short-pitch winding. Among them, the full-pitch winding means that the pitch of the stator winding is equal to the pole pitch, and the short-pitch winding means that the pitch of the stator winding is less than the pole pitch.

[0050] Figure 3 FIG. 4 is a three-dimensional structural schematic diagram of the stator of the flat wire motor according to an embodiment of the present application. Figure 4 FIG. 5 is a front view structural schematic diagram of the stator of the flat wire motor according to an embodiment of the present application. As Figure 3 and Figure 4 shown, in an embodiment of the present application, the stator includes a stator core 10 and a stator winding 20.

[0051] Figure 5 FIG. 6 is a top view structural schematic diagram of the stator core according to an embodiment of the present application. As Figure 5 shown, a plurality of stator slots 11 are provided on the inner wall of the stator core 10. The number of stator slots 11 can be represented by Z, and Z can be a natural number that is a multiple of 3. Specifically, 48 or 54 can be selected. Referring to Figures 1 - 3 together, Z stator slots 11 are provided on the inner wall of the stator core 10 and are evenly arranged along the circumferential direction of the inner wall of the stator core 10. Any stator slot 11 extends in the axial direction of the stator core 10 (such as the Z direction shown in Figure 1 ) and penetrates through the inner wall of the stator core 10 along the axial direction of the stator core 10. The stator core 10 is divided into an insertion end 10a and an extraction end 10b along its axial direction, and any stator slot 11 can extend from the insertion end 10a to the extraction end 10b.

[0052] Referring to Figure 3 and Figure 4 together, in an embodiment of the present application, the stator winding 20 includes a flat wire conductor 21 inserted into the stator slot 11, and the cross-section of the flat wire conductor 21 can be rectangular. Among them, the flat wire conductor 21 can be formed by a hairpin coil. Figure 6 FIG. 7 is a structural schematic diagram of the hairpin coil according to an embodiment of the present application. As Figure 6 shown, in an embodiment of the present application, the hairpin coil 22 includes a leg 221 provided in the stator slot 11 and a connecting portion 222 and a bending portion 223 provided outside the stator slot 11. The connecting portion 222 can be formed into a U shape or a V shape. Among them, referring to Figure 3 and Figure 6, in an embodiment of the present application, the hairpin coil 22 can be inserted into the stator slot 11 and then bent to form a bent portion 223. After the insertion is completed, the leg portion 221 of the hairpin coil 22 inserted into the stator slot 11 forms a flat wire conductor 21. After bending, the turning directions of the bent portions 223 of the hairpin coil 22 are kept consistent. Among them, after the hairpin coil 22 is inserted into the stator slot 11, its connecting portion 222 forms the insertion end 20a of the stator winding 20, and the bent portion 223 forms the welding end 20b of the stator winding 20.

[0053] Figure 7 is a top view structural schematic diagram of the flat wire conductor inserted into the stator slot in an embodiment of the present application. As Figure 7 shown, in an embodiment of the present application, N layers of flat wire conductors 21 can be arranged in any stator slot 11, and N can be 6, 8, 10 or 12, or a natural number greater than 12. As Figure 7 shown, in an embodiment of the present application, N is 6, that is, 6 layers of flat wire conductors 21 are arranged in each stator slot 11. It can be understood that Figure 7 the number of layers of the flat wire conductors 21 shown is only for illustrative purposes. In addition to arranging 6 layers of flat wire conductors 21, 10 layers of flat wire conductors 21 can also be arranged.

[0054] Continue to refer to Figure 3 and Figure 7 , in an embodiment of the present application, the flat wire conductors 21 inserted into the stator slot 11 can form an m-phase winding through grouped connection. m can be 2, 3, 4, 5, or 6, etc., that is, the number of phases of the corresponding flat wire motor can be two-phase, three-phase, four-phase, five-phase, six-phase or more phases. Taking a three-phase winding as an example, the stator winding can be divided into a first-phase winding, a second-phase winding and a third-phase winding, corresponding to a U-phase winding, a V-phase winding and a W-phase winding respectively. In the m-phase winding, any phase winding can include multiple phase units. When connecting, the phase units of the first-phase winding, the phase units of the second-phase winding and the phase units of the third-phase winding are arranged in a periodic manner along the inner wall of the stator core in sequence. Among them, each phase unit of each phase winding is a pole phase, and the number of stator slots corresponding to each phase unit is the number of slots per pole per phase.

[0055] Among them, it can be understood that the number of phases of the flat wire motor is not specifically limited in the present application. The stator winding can be a single-phase winding, a three-phase winding or a six-phase winding.

[0056] Figure 8 is a phase belt distribution diagram of the U-phase winding in an embodiment of the present application. Refer to Figure 7 and Figure 8, in an embodiment of the present application, any phase unit of the U-phase winding includes at least two phase belts. Each phase belt of any phase unit may include adjacent two layers of flat wire conductors 21, and adjacent phase belts of any phase unit are offset by one stator slot. Wherein, N is an even number greater than or equal to 4. Thus, in any phase unit, N layers of flat wire conductors 21 can be divided into N / P phase belts. Taking N as 6 as an example, 6 layers of flat wire conductors 21 are arranged in each stator slot 11, and adjacent 2 layers of flat wire conductors can form a phase belt, and the number of phase belts can be 3. Taking N as 10 as an example, 10 layers of flat wire conductors 21 are arranged in each stator slot 11, and adjacent 2 layers of flat wire conductors 21 form a phase belt, and the number of phase belts can be 5.

[0057] Continue to refer to Figure 8 , in the stator of the flat wire motor according to the embodiment of the present application, adjacent phase belts of any phase unit are offset by one stator slot 11 in the clockwise direction or in the counterclockwise direction, that is, the directions of the stator slots 11 offset by adjacent phase belts of the same phase unit are the same. Thus, the equivalent pitch of the stator winding is made less than the pole pitch of the stator winding to the greatest extent. Compared with that in any phase unit of each phase winding of the traditional short pitch, which only includes two phase belts, and adjacent phase belts of any phase unit are offset by one or two stator slots, that is, the pitches of the traditional short pitch windings are 8 or 7 respectively, the flat wire motor according to the embodiment of the present application can effectively reduce the harmonic winding coefficient of the motor while obtaining a high fundamental wave winding coefficient.

[0058] Figure 9 is the phase belt distribution diagram of the U-phase winding in another embodiment of the present application. Refer to Figure 9 , in an embodiment of the present application, among multiple phase belts of the same phase unit, from the 1st layer to the Nth layer direction of one stator slot, among the first several adjacent phase belts, they can be offset by one stator slot in the clockwise direction in sequence, and among the last several adjacent phase belts, they are then offset by one stator slot 11 in the counterclockwise direction in sequence; or, among the first several adjacent phase belts, they can be offset by one stator slot in the counterclockwise direction in sequence, and among the last several adjacent phase belts, they are then offset by one stator slot 11 in the clockwise direction in sequence; or, adjacent phase belts can be alternately offset by one stator slot 11 in the clockwise direction and in the counterclockwise direction in sequence. It should be noted that when adjacent phase belts of the same phase unit are offset by one stator slot using the above combination of clockwise and counterclockwise directions, any phase unit is symmetrically arranged along the perpendicular bisector of the axis direction of the stator core.

[0059] Among them, it should be noted that in the present application, the direction of the offset slot number between adjacent phase belts is not limited, and can be freely combined to flexibly meet different motor design requirements, so as to suppress the torque ripple of the motor and reduce the harmonic winding coefficient, thereby improving the motor performance.

[0060] In an embodiment of the present application, each phase winding includes at least one branch. When each phase winding includes two or more parallel branches, each parallel branch includes flat wire conductors in different layers distributed in the same-layer phase belts of adjacent phase units. Moreover, each of the flat wire conductors in the same phase belt is evenly distributed in different parallel branches, so that the potential balance can be maintained between each parallel branch of each phase.

[0061] As Figure 8 shown, in an embodiment of the present application, each phase winding of the stator winding 20 is respectively composed of two parallel circuits. Taking the two parallel branches of the U phase as an example, denoted as branch 1 and branch 2, the flat wire conductors in different layers in the same phase belt belong to different parallel branches, and the flat wire conductors in different layers in the same-layer phase belts of adjacent phase units belong to different parallel branches. Among them, taking the phase belt composed of slots 1, 2, and 3 and the phase belt composed of slots 10, 11, and 12 as an example, the two phase belts belong to two different phase units. Denote the phase belt composed of slots 1, 2, and 3 as phase belt A, and the phase belt composed of slots 10, 11, and 12 as phase belt B. Then, the first-layer flat wire conductor in phase belt A belongs to branch 1, the second-layer flat wire conductor in phase belt A belongs to branch 2, the first-layer flat wire conductor in phase belt B belongs to branch 2, and the second-layer flat wire conductor in phase belt B belongs to branch 1. By arranging the flat wire conductors in different layers in branch 1 and branch 2 in this way, the potential balance between branch 1 and branch 2 can be maintained, and the generation of circulating current can be reduced.

[0062] As Figure 9 shown, in another embodiment of the present application, each phase winding of the stator winding 20 is respectively composed of four parallel circuits, denoted as branch 1, branch 2, branch 3, and branch 4. Among them, taking branch 1 as an example, in the phase belt composed of slots 7 and 8, the second-layer flat wire conductor of slot 7 belongs to branch 1, the first-layer flat wire conductor of slot 8 belongs to branch 2, the second-layer flat wire conductor of slot 8 belongs to branch 3, and the first-layer flat wire conductor of slot 7 belongs to branch 4. The connection of the flat wire conductors in other layers can be referred to Figure 9 for connection to form different parallel branches.

[0063] In an embodiment of the present application, each phase winding is evenly divided into N / 2 parts along the axis direction of the stator core. In each part, the adjacent two-layer flat wire conductors are connected to form a coil layer, and each part includes two coil layers. In a possible implementation manner of the present application, in each phase winding, the adjacent coil layers are connected by a single cross wire, that is, the cross-layer connection is realized through a single cross wire, which helps to simplify the structure of the stator winding and is thus convenient to implement.

[0064] Figure 10 For Figure 8 the single-branch expansion diagram of the U-phase winding in Figure 10, in an embodiment of the present application, on the opposite sides of the stator winding 20 along the axial direction of the stator core 10 are the wire insertion end 20a and the welding end 20b respectively. On the side of the welding end 20b, the span of a single cross wire between different coil layers is equal, so that the turning angles of the welding end 20b are the same, which can simplify the turning, welding and coating processes.

[0065] An embodiment of the present application also provides a flat wire motor, which includes a rotor and the stator of the embodiment of the present application. The rotor is arranged in the space surrounded by the inner wall of the stator core.

[0066] An embodiment of the present application also provides a powertrain, which includes a reducer and the above-mentioned flat wire motor. Among them, the flat wire motor is in transmission connection with the reducer. Specifically, the drive shaft of the flat wire motor and the input shaft of the reducer can be in transmission connection through transmission parts such as couplings, so as to output the driving force from the flat wire motor to the reducer.

[0067] The vehicle provided by the embodiment of the present application includes the above-mentioned powertrain. The above-mentioned powertrain is arranged in the vehicle and provides operating power for the vehicle. Specifically, in this embodiment, the vehicle can be specifically a new energy vehicle driven by electric energy, such as. Among them, the new energy vehicle can specifically be a hybrid electric vehicle, a pure electric vehicle or a fuel cell electric vehicle, etc., or it can also be a vehicle using high-efficiency energy storage devices such as supercapacitors, flywheel batteries or flywheel energy storage devices as the electric energy source.

[0068] The stator winding of the embodiment of the present application will be described in detail below in conjunction with specific embodiments.

[0069] Embodiment 1

[0070] This embodiment is a stator winding and a stator containing the stator winding. The stator also includes a stator core. Among them, the number of stator slots of the stator core is 54, the number of conductor layers in the stator slots is 6 layers, and the number of poles of the stator winding is 6. The stator winding is divided into phase U, phase V and phase W, and the number of parallel branches set for each phase winding is 2. Each phase winding can be divided into 6 pole phases, that is, 6 phase units, and the number of slots per pole per phase is 3. The distribution diagram of each phase belt in the phase U winding of this embodiment can be referred to Figure 8 .

[0071] As Figure 8As shown, each stator slot contains 6 layers of rectangular conductors. Among them, the 1st layer is the bottom layer of the stator slot, and the 6th layer is the slot opening layer. "+" represents current flowing into the conductor, and "-" represents current flowing out of the conductor. Among them, in any phase unit, two adjacent layers of rectangular conductors form a phase belt, that is, each phase unit of each phase winding can be divided into three phase belts. The adjacent phase belts in the same phase unit are staggered by one stator slot, and the staggering direction is to move 1 slot along the x direction in the figure, so that the equivalent pitch of the stator winding can be 7, achieving the effect of short pitch. It should be noted that Figure 8 the x direction in the actual stator core can be clockwise or counterclockwise.

[0072] Among them, both parallel branches of each phase winding traverse the phase belts and the positions of the rectangular conductor layers that can be arranged. Therefore, the number of each parallel branch can maintain potential balance and no circulating current will be generated. Taking Figure 8 the phase belt distribution shown as an example, the phase belt composed of the 1st and 2nd layer rectangular conductors in slots 1, 2, and 3 is denoted as phase belt A1, the phase belt composed of the 3rd and 4th layer rectangular conductors in slots 54, 1, and 2 is denoted as phase belt A2, and the phase belt composed of the 5th and 6th layer rectangular conductors in slots 53, 54, and 1 is denoted as phase belt A3; the phase belt composed of the 1st and 2nd layer rectangular conductors in slots 10, 11, and 12 is denoted as phase belt B1, the phase belt composed of the 3rd and 4th layer rectangular conductors in slots 9, 10, and 11 is denoted as phase belt B2, and the phase belt composed of the 5th and 6th layer rectangular conductors in slots 8, 9, and 10 is denoted as phase belt B3, ……, and so on. The phase belt composed of the 1st and 2nd layer rectangular conductors in slots 46, 47, and 48 is denoted as phase belt F1, the phase belt composed of the 3rd and 4th layer rectangular conductors in slots 45, 46, and 47 is denoted as phase belt F2, and the phase belt composed of the 5th and 6th layer rectangular conductors in slots 44, 45, and 46 is denoted as phase belt F3. When connecting, the rectangular conductors of different layers in the same-layer phase belts in adjacent phase units are distributed in different parallel branches, and the rectangular conductors in the same phase belt are evenly distributed in different parallel branches. For example, in phase belt A1 and phase belt B1, if the 1st layer rectangular conductor in phase belt A1 belongs to branch 1, then the 2nd layer rectangular conductor in phase belt A1 belongs to branch 2, the 1st layer rectangular conductor in phase belt B1 belongs to branch 2, and the 2nd layer rectangular conductor in phase belt B1 belongs to branch 1. And so on, the rectangular conductors in each phase belt are respectively connected to different branches. Figure 11 Figure 9 is a schematic diagram of the connection structure of branch 2, Figure 12 which is Figure 11 a schematic diagram of the enlarged connection structure of some rectangular conductors in Figure 8 , Figure 11 and Figure 12, during connection, a single jumper wire can be used to connect each coil layer at the welding ends of the stator winding. Among them, for exemplary illustration, in branch 2, the connection method of 5-layer and 6-layer flat wire conductors is taken as an example. For 28 slots of 5-layer flat wire conductors, connect to 37 slots of 6-layer flat wire conductors, then connect to 46 slots of 5-layer flat wire conductors, then connect to 1 slot of 6-layer flat wire conductors, then connect to 8 slots of 5-layer flat wire conductors, then connect to 17 slots of 6-layer flat wire conductors, then connect to 26 slots of 5-layer flat wire conductors, then connect to 35 slots of 6-layer flat wire conductors, then connect to 44 slots of 5-layer flat wire conductors, then connect to 53 slots of 6-layer flat wire conductors, then connect to 9 slots of 5-layer flat wire conductors, then connect to 18 slots of 6-layer flat wire conductors, then connect to 27 slots of 5-layer flat wire conductors, then connect to 36 slots of 6-layer flat wire conductors, then connect to 45 slots of 5-layer flat wire conductors, then connect to 54 slots of 6-layer flat wire conductors, then connect to 10 slots of 5-layer flat wire conductors, then connect to 19 slots of 4-layer flat wire conductors. Thus, the traversal of 5-layer and 6-layer flat wire conductors is completed. The connection methods of flat wire conductors of other layers can refer to Figure 8 , Figure 11 and Figure 12 , which will not be elaborated one by one here.

[0073] Figure 12 is a schematic diagram of the connection structure of a part in branch 2. As Figure 12 shows, the 10-slot 5-layer flat wire conductor is connected to the 19-slot 4-layer flat wire conductor to complete the jumper connection between adjacent coil layers, that is, to jump from the phase belt composed of 5- and 6-layer flat wire conductors to the phase belt composed of 3- and 4-layer flat wire conductors, and the span is also 9. In addition, when jumping from the 10-slot 3-layer flat wire conductor to the 19-slot 2-layer flat wire conductor, the span is also 9. Thus, it can be seen from Figures 10 to 12 that the span of each hairpin coil at the welding end of the stator winding is 9, so that the twisting directions of each hairpin coil at the welding end can be kept consistent, reducing the processing difficulty.

[0074] It should be noted that Figure 8 the phase belt distribution in Figure 8 is only for exemplary illustration. By swapping the “+” and “-” signs in Figure 8 , for example, simultaneously changing “U + ” to “U - ” and changing “U - ” to “U + ”, and making corresponding modifications to the V phase and W phase as well, they are all within the protection scope of this application.

[0075] Figure 13 and Figure 14 are schematic diagrams of the structure of the motor stator core and the U-phase winding of this embodiment. Among them, Figure 13 highlights the characteristics of the wire insertion end, Figure 14 highlights the characteristics of the welding end. As Figure 13As shown, at the wire insertion end, no additional jumper wires are required to connect adjacent coil layers. As Figure 14 shown, at the welding end of the stator winding, adjacent coil layers are connected by a single jumper wire. Specifically, between the second layer and the third layer, and between the fourth layer and the fifth layer, they are connected by a single jumper wire, and the span of the welding end is maintained at 9. Therefore, the span and the turning angle of the winding welding end are the same, and each welding point is symmetrically distributed around the circumference.

[0076] Embodiment 2

[0077] This embodiment is a stator winding and a stator containing the stator winding. The stator further includes a stator core. Among them, the number of stator slots of the stator core is 48, the number of conductor layers in the stator slots is 10, and the number of poles of the stator winding is 8. The stator winding is divided into phase U, phase V, and phase W, and the number of parallel branches provided in each phase winding is 4. Each phase winding can be divided into 8 phase units, and the number of slots per pole per phase is 2. Taking the phase U winding as an example, the phase belt distribution diagram of the phase U winding in this embodiment can be referred to Figure 9 .

[0078] As Figure 9 shown, each stator slot contains 10 layers of flat wire conductors. Among them, the first layer is the slot bottom layer of the stator slot, and the sixth layer is the slot opening layer. "+" represents current flowing into the conductor, and "-" represents current flowing out of the conductor. Among them, in any phase unit, adjacent two layers of flat wire conductors form a phase belt, that is, each phase unit of each phase winding can be divided into five phase belts. As Figure 9 shown, in any phase unit, the first layer and the second layer of flat wire conductors form the first phase belt, the third layer and the fourth layer of flat wire conductors form the second phase belt opposite to it, the fifth layer and the sixth layer of flat wire conductors form the third phase belt, the seventh layer and the eighth layer of flat wire conductors form the fourth phase belt, and the ninth layer and the tenth layer of flat wire conductors form the fifth phase belt. In the same phase unit, the second phase belt (such as the phase belt formed by the third layer and the fourth layer of flat wire conductors in slots 8 and 9) is misaligned by 1 slot in the direction opposite to the x direction in the figure relative to the first phase belt (such as the phase belt formed by the first layer and the second layer of flat wire conductors in slots 7 and 8). The third phase belt (such as the phase belt formed by the fifth layer and the sixth layer of flat wire conductors in slots 9 and 10) is misaligned by 1 slot in the direction opposite to the x direction in the figure relative to the second phase belt (such as the phase belt formed by the third layer and the fourth layer of flat wire conductors in slots 8 and 9). The fourth phase belt (such as the phase belt formed by the seventh layer and the eighth layer of flat wire conductors in slots 8 and 9) is misaligned by 1 slot in the x direction in the figure relative to the third phase belt (such as the phase belt formed by the fifth layer and the sixth layer of flat wire conductors in slots 8 and 9). The fifth phase belt (such as the phase belt formed by the ninth layer and the tenth layer of flat wire conductors in slots 7 and 8) is misaligned by 1 slot in the x direction in the figure relative to the fourth phase belt (such as the phase belt formed by the seventh layer and the eighth layer of flat wire conductors in slots 8 and 9). As Figure 9As shown, in this setting method, the equivalent pitch of the stator winding is 7, thus achieving the effect of short pitch. It should be noted that Figure 9 The x - direction in the actual stator core in Figure 9 can be clockwise or counter - clockwise.

[0079] Among them, Figure 9 In the stator winding shown, when each parallel branch is connected, different flat - wire conductors of the same - layer phase belt can be connected first. After the connection between the first - phase belts of different phase units is completed, the flat - wire conductors between different coil layers can be connected through a single cross - wire. For example, when the flat - wire conductors of the first - phase belt are all connected, the flat - wire conductors of the first - phase belt can be connected to those of the second - phase belt. In this connection method, the span of the single cross - wire for each layer of flat - wire conductors at the welding end side is 8. Thus, in the stator winding of this embodiment, the spans at the welding end can be kept completely consistent, all being 8, so that the turning angles of the wire legs of the hairpin coils are the same, simplifying the turning, welding, and coating processes.

[0080] Among them, the four parallel branches in each phase winding evenly traverse all the flat - wire conductors of the phase belt that can be arranged. Therefore, the number of each parallel branch can maintain potential balance and no circulating current will be generated.

[0081] Perform simulation calculations on the winding coefficients and torque fluctuations of the stator winding, full - pitch winding, traditional short - pitch winding with a pitch of 8 (as Figure 1 shown), and traditional short - pitch winding with a pitch of 7 (as Figure 2 shown) in the above - mentioned embodiment. The calculation results are as follows:

[0082] Table 1

[0083]

[0084] From the comparison data of Embodiment 1 and the traditional short - pitch windings in Table 1, it can be seen that the equivalent pitch of Embodiment 1 is 7, but the fundamental - wave winding coefficient is much higher than that of the traditional short - pitch winding with an equivalent pitch of 7 and is close to that of the traditional short - pitch winding with an equivalent pitch of 8, greatly reducing the influence of short pitch on the average torque. In addition, the 5th, 7th, 11th, and 13th - harmonic winding coefficients of Embodiment 1 are much lower than those of the traditional short - pitch windings, and the weakening effect on the 5th, 7th, 11th, and 13th - harmonic magnetic fields on the armature side is stronger.

[0085] Figure 15 Figure is the comparison diagram of torque fluctuations at the peak - torque operating point of the motor with the winding of Embodiment 1, the full - pitch winding, and the traditional short - pitch winding motor, as Figure 15As shown, the torque ripple of the motor with short-pitch windings has decreased significantly. The peak-to-peak value of the torque ripple of the motor with full-pitch windings is 17.3 Nm. The peak-to-peak values of the torque ripple of the motor with traditional short-pitch windings (equivalent pitch of 8) and the short-pitch winding motor of Example 1 are 10.4 Nm and 9.7 Nm respectively, a decrease of 40% and 44% respectively. Obviously, the torque ripple suppression effect of the flat wire short-pitch winding structure of Example 1 is better.

[0086] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present application can easily think of changes or substitutions, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A stator of a flat wire motor, characterized in that: The invention comprises a stator core and a stator winding, wherein the inner wall of the stator core is uniformly provided with a plurality of stator slots in the circumferential direction, and the stator winding comprises a flat wire conductor inserted in the stator slots, and any of the stator slots is provided with N layers of the flat wire conductor, where N is an even number greater than or equal to 4, wherein: Each of the flat wire conductors is connected to form an m-phase winding, each phase winding includes a plurality of phase units that are evenly and spaced apart along the circumference of the stator core, any of the phase units of each phase winding includes at least two phase belts, each of the phase belts of any of the phase units includes two adjacent layers of the flat wire conductors, and adjacent phase belts of any of the phase units are offset by one stator slot; adjacent phase belts of any of the phase units are sequentially offset by one stator slot in the clockwise direction and then by one stator slot in the counterclockwise direction along the circumference of the stator, or adjacent phase belts of any of the phase units are sequentially offset by one stator slot in the counterclockwise direction and then by one stator slot in the clockwise direction along the circumference of the stator; Any of the phase units are symmetrically arranged along a perpendicular midline perpendicular to the axial direction of the stator core; A single wire is used to achieve cross-layer connection between adjacent phase belts of any phase unit.

2. The stator according to claim 1, characterized in that: Each phase winding is equally divided into N / 2 parts along the radial direction of the stator core, and two adjacent layers of the flat wire conductors in each part are connected to form a coil layer.

3. The stator according to claim 2, characterized in that: In each phase winding, adjacent coil layers are connected via a single crossover wire.

4. The stator according to claim 2 or 3, characterized in that: The two opposite sides of the stator winding along the axial direction of the stator core are respectively a wire insertion end and a welding end. On the welding end side, the spans of single cross-wires between different coil layers are equal.

5. The stator according to any one of claims 1 to 3, characterized in that: Each phase winding includes at least one branch.

6. The stator according to claim 5, characterized in that: When each phase winding includes at least two parallel branches, each of the parallel branches includes flat wire conductors of different layers distributed in the same layer of the phase belts of each adjacent phase unit, and each of the flat wire conductors in the same phase belt is evenly distributed in different parallel branches.

7. The stator according to any one of claims 1 to 3, characterized in that: The number of stator slots on the inner wall of the stator core is Z, the number of phases of the stator winding is m, the number of poles of the stator winding is 2p, and p is an integer. The number of stator slots per pole and per phase is q, and Z, m, 2p and q satisfy: q=Z / 2pm.

8. A flat wire motor, characterized in that: It comprises a rotor and a stator as claimed in any one of claims 1 to 7, wherein the rotor is arranged in a space surrounded by an inner wall of the stator core.

9. A powertrain, characterized in that: It comprises a reducer and the flat wire motor as claimed in claim 8, wherein the flat wire motor is drivingly connected to the reducer.

10. A vehicle, characterized in that: Comprising the powertrain as claimed in claim 9.

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