Double-layer flat wire winding structure of a motor

Abstract

The present invention relates to a double-layer flat wire winding structure of a motor, which includes a stator core and a three-phase flat wire winding installed in the stator core. An insulating paper is provided between the stator core and the flat wire winding. The stator core is provided with Z slots, and the number of slots per pole per phase of the stator core is set to q. Each slot of the stator core is embedded with i flat conductors. Each phase of the winding includes multiple parallel branches, and each parallel branch is formed by connecting multiple hairpin flat conductors in series. Each hairpin flat conductor has an input side and an output side. The hairpin flat conductors are embedded in the stator core in equal pitch sequence, and a short-pitch winding is formed by twisting the welding ends. All the input sides and output sides of each parallel branch are completely symmetrically distributed on the magnetic path. In the present invention, by making the number of all the input sides and output sides of each parallel branch embedded on different layers exactly the same, a double-layer winding is formed, so that each parallel branch is completely symmetric on the magnetic path, and the back electromotive force, resistance and inductance are balanced, thereby eliminating the loop current.

Description

Technical Field

[0001] The present invention relates to the technical field of flat wire motors, and particularly to a double-layer flat wire winding structure for a motor. Background Art

[0002] At present, the manufacturing of the stator winding of flat wire motors is relatively complex. Due to process limitations, there is a problem of loop current in the magnetic circuit of the flat wire winding. To solve the problem of winding circulating current, a reasonable design of the winding spatial distribution is required to balance the positions of the conductors connected to each branch to achieve resistance and inductance balance. The higher the motor frequency, the more urgent the need for transposition. The larger the number of conductors per slot and the number of parallel branches, the more complex the loop design.

[0003] For new energy motors, especially drive motors, the peak speed generally exceeds 10,000 rpm. High-speed motors have high requirements for NVH. Round wire motors usually adopt double-layer short-pitch windings, which can effectively reduce stator-side harmonics and optimize the NVH performance of the motor. By reasonably designing the flat wire winding structure, the stator-side harmonics can also be effectively reduced.

[0004] It is difficult to adjust the number of conductors per slot in the existing stator winding of flat wire motors. Generally, the number of turns is adjusted by adjusting the number of parallel branches. The Chinese patent application with the publication number CN111200328A discloses a winding structure with 4-way parallel connection that does not generate loop current, but this winding is a full-pitch single-layer winding, with a relatively large amount of harmonic content on the stator side, and all slots are in-phase windings, resulting in relatively large losses caused by AC resistance. Summary of the Invention

[0005] The object of the present invention is to provide a double-layer flat wire winding structure for a motor in view of the corresponding deficiencies in the prior art. By changing layers and transposing, each phase winding forms a short-pitch winding, and all the input sides and output sides of each parallel branch are jointly embedded on different layers with exactly the same number, forming a double-layer winding, so that each parallel branch is completely symmetric in the magnetic circuit, and the back electromotive force, resistance, and inductance are balanced, thereby eliminating loop current.

[0006] The object of the present invention is achieved by the following solution: A double-layer flat wire winding structure for an electric motor, comprising a stator core and a three-phase flat wire winding installed in the stator core. An insulating paper is provided between the stator core and the flat wire winding. The stator core is provided with Z slots, where Z is a multiple of 12. The number of slots per pole per phase of the stator core is set to q, and q is equal to 2. Each slot of the stator core is embedded with i flat conductors. The number of poles of the three-phase flat wire winding is 2P. Each phase of the three-phase flat wire winding is provided with j parallel circuits. Each of the parallel branches is composed of W hairpin flat conductors, and W = Zi / 6j. The hairpin flat conductors are all inserted from one end of the stator core. The input side and the output side of each flat conductor are embedded in adjacent layers and are separated by K slots. That is, the input side of the first hairpin flat conductor is embedded in the first layer of the first slot of the stator core, and the output side of the first hairpin flat conductor is embedded in the second layer of the (K + 1)-th slot of the stator core. The input side of the second hairpin flat conductor is embedded in the first layer of the second slot of the stator core, and the output side of the second hairpin flat conductor is embedded in the second layer of the (K + 2)-th slot of the stator core, and so on. After embedding the 1st and 2nd layers, the 3rd and 4th layers are embedded. Among them, K = Z / 2P, q = Z / 3*2P, so that the same-phase winding structure is arranged in the odd-numbered slots, and the two-phase winding structure is arranged in the even-numbered slots. The span from the input side to the output side of the welding end is changed by changing the bending angle of the hairpin flat conductor at the welding end.

[0007] Further, each of the parallel branches includes a full-pitch wave winding coil with a span of K, a short-pitch layer-changing wave winding coil with a span of K - 1, a long-pitch layer-changing wave winding coil with a span of K + 2, and in some cases, a short-pitch transposed wave winding coil with a span of K - 1;

[0008] By layer-changing and transposing, each phase winding is formed into a short-pitch winding. The number of all input sides and output sides of each parallel branch embedded on different layers is exactly the same. Therefore, H is defined as the basis for judging whether each parallel branch has a transposed coil, H = 2W / ij, and H is an integer;

[0009] When H is equal to 1, each parallel branch undergoes layer-changing once through P coils, and a total of i / 2 - 1 times of layer-changing are performed, and there is no transposed coil;

[0010] When H is greater than 1, each parallel branch undergoes transposing once through P coils and layer-changing once through 2P coils.

[0011] Further, when the number of the parallel branches is 2, the winding directions of the two parallel coils in each phase are opposite, the layers of the input sides and the output sides are opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

[0012] Further, when the number of parallel branches is 4, the number of slots in the first and second branches of each phase is adjacent, the winding directions are the same, and the number of layers is the same. The number of slots in the third and fourth branches is adjacent, the winding directions are the same, and the number of layers is the same. The winding directions of the coils in the first and fourth branches are opposite, the number of layers of the input side and the output side is opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] 1. The output side and the input side of the hairpin-shaped flat conductor of the winding structure of the present invention are symmetrically distributed, there is no circulating current between different parallel branches and different phases, and unnecessary winding losses will not be introduced;

[0015] 2. This winding structure can effectively weaken the stator-side harmonics, improve the sinusoidality of the current, reduce the temperature rise caused by current harmonics, and at the same time improve the NVH performance of the motor;

[0016] 3. Since the AC copper loss caused by the skin effect of the different-phase same-slot winding is smaller than that of the same-phase same-slot winding, the double-layer winding can also reduce the AC loss, improve the efficiency at high speed, avoid local overheating of the winding, and improve the service life of the motor;

[0017] 4. By simply combining the input ends and output ends of the parallel branches of each phase winding in series and parallel, the number of turns of the coil can also be adjusted, which is beneficial to platform design and cost reduction.

[0018] 5. This winding structure is applicable to stators with various numbers of slots, different numbers of layers and parallel branches, with flexible design and wide application. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a schematic structural diagram of the present invention;

[0020] Figure 2 is a schematic structural diagram of the flat wire winding of the present invention;

[0021] Figure 3 is an unfolded view of all the input sides and output sides of the three-phase flat wire winding of the present invention in the slots;

[0022] Figure 4 is a schematic structural diagram of the U-phase winding of the present invention;

[0023] Figure 5 is a schematic structural diagram of two groups of 4-turn coils of the present invention;

[0024] Figure 6 is a schematic structural diagram of two groups of single-turn coils connected in series of the present invention;

[0025] Figure 7 is a schematic structural diagram of a coil with a span of 6 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] As shown Figures 1 to 7 in the figure, a double-layer flat wire winding structure of a motor includes a stator core and a three-phase flat wire winding installed in the stator core. An insulating paper is provided between the stator core and the flat wire winding. The stator core is provided with Z slots, where Z is a multiple of 12. The number of slots per pole per phase of the stator core is set to q, and q is equal to 2. Each slot of the stator core is embedded with i flat conductors. The number of poles of the three-phase flat wire winding is 2P. Each phase of the three-phase flat wire winding is provided with j parallel circuits. Each parallel branch is composed of W hairpin flat conductors, and W = Zi / 6j. All the hairpin flat conductors are inserted from one end of the stator core. The input side and the output side of each flat conductor are embedded in adjacent layers and are separated by K slots. That is, the input side of the first hairpin flat conductor is embedded in the first layer of the first slot of the stator core, and the output side of the first hairpin flat conductor is embedded in the second layer of the (K + 1)-th slot of the stator core. The input side of the second hairpin flat conductor is embedded in the first layer of the second slot of the stator core, and the output side of the second hairpin flat conductor is embedded in the second layer of the (K + 2)-th slot of the stator core, and so on. After embedding layers 1 and 2, layers 3 and 4 are embedded. Among them, K = Z / 2P, q = Z / (3 * 2P), so that the same-phase winding structure is in the odd-numbered slots and the two-phase winding structure is in the even-numbered slots. The span from the input side to the output side of the welding end is changed by changing the bending angle of the hairpin flat conductor at the welding end.

[0027] Each parallel branch includes a full-pitch wave winding coil with a span of K, a short-pitch layer-changing wave winding coil with a span of K - 1, and a long-pitch layer-changing wave winding coil with a span of K + 2. In some cases, it also includes a short-pitch transposed wave winding coil with a span of K - 1;

[0028] By layer-changing and transposing, each phase winding forms a short-pitch winding. The number of all input sides and output sides of each parallel branch embedded in different layers is exactly the same. Therefore, H is defined as the basis for judging whether each parallel branch has a transposed coil. H = 2W / ij, and H is an integer;

[0029] When H is equal to 1, each parallel branch undergoes 1 layer-changing through P coils, and a total of i / 2 - 1 layer-changings are performed, and there is no transposed coil;

[0030] When H is greater than 1, each parallel branch undergoes 1 transposition through P coils and 1 layer-changing through 2P coils.

[0031] When the number of parallel branches is 2, the winding directions of the two parallel coils in each phase are opposite, the layers of the input side and the output side are opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

[0032] When the number of parallel branches is 4, the number of slots in the first and second branches of each phase is adjacent, the winding directions are the same, and the number of layers is the same. The number of slots in the third and fourth branches is adjacent, the winding directions are the same, and the number of layers is the same. The winding directions of the coils in the first and fourth branches are opposite, the number of layers of the input side and the output side is opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

[0033] This embodiment includes a stator core 1 and a flat wire winding 2. The flat wire winding 2 is composed of symmetrically distributed U, V, and W three-phase windings. The stator core and the winding are separated by insulating paper. The number of slots is 48, the number of poles of the motor is 8, it is a three-phase motor, the number of slots per pole per phase q is 2, and each phase has 4 parallel paths; 8 layers of flat conductors are sequentially embedded in each slot of the stator core from the slot opening to the slot bottom, then P = 4, W = 16, H = 1, j = 1.

[0034] As shown in the appendix Figure 1 shown, the three-phase windings adopt a Y-type connection, and all input sides and output sides are distributed in the stator core as Figure 3 shown, where A, B, and C represent the input sides of the three-phase windings, and X, Y, and Z represent the output sides of the three-phase windings, that is, current flows in from the conductor positions shown by A (or B, C) and flows out from the conductor positions shown by X (or Y, Z).

[0035] Each phase winding is composed of 4 parallel branches. A represents the first parallel branch of the U-phase winding, AA represents the second parallel branch of the U-phase winding, AAA represents the third parallel branch of the U-phase winding, and AAAA represents the fourth parallel branch of the U-phase winding. Similarly, B and C respectively represent the V-phase and W-phase windings. A1 represents the input side of the first coil of the first parallel branch of the U-phase winding, and X1 represents the output side of the first coil of the first parallel branch of the U-phase winding.

[0036] Each parallel branch is formed by connecting 16 coils 12 in series. Arabic numerals represent the connection sequence of the series branches. The current path of the first parallel branch of the U-phase is: A1 - X1 - A2 - X2 - A3 - X3 - A4 - X4 - A5 - X5 - A6 - X6 - A7 - X7 - A8 - X8 - A9 - X9 - A10 - X10 - A11 - X11 - A12 - X12 - A13 - X13 - A14 - X14 - A15 - X15 - A15 - X16

[0037] A1 is located in the first layer and the first slot, X1 is located in the second layer and the seventh slot, A2 is located in the first layer and the thirteenth slot, X2 is located in the second layer and the nineteenth slot, A3 is located in the first layer and the twenty-fifth slot, X3 is located in the second layer and the thirty-first slot, A4 is located in the first layer and the thirty-seventh slot, X4 is located in the second layer and the forty-third slot, and the welding end span is 6 for all;

[0038] A5 is located in the third layer and the forty-eighth slot, X5 is located in the fourth layer and the sixth slot, and the span from X4 to A5 is 5;

[0039] A6 is located at the 12th slot on the 3rd layer, X6 is located at the 18th slot on the 4th layer, A7 is located at the 24th slot on the 3rd layer, X7 is located at the 30th slot on the 4th layer, A8 is located at the 36th slot on the 3rd layer, X8 is located at the 42nd slot on the 4th layer, and the span of the welding ends is 6 for all;

[0040] A9 is located at the 2nd slot on the 5th layer, X9 is located at the 8th slot on the 6th layer, and the span from X8 to A9 is 8.

[0041] A10 is located at the 14th slot on the 5th layer, X10 is located at the 20th slot on the 6th layer, A11 is located at the 26th slot on the 5th layer, X11 is located at the 32nd slot on the 6th layer, A12 is located at the 38th slot on the 5th layer, X12 is located at the 44th slot on the 6th layer, and the span of the welding ends is 6 for all;

[0042] A13 is located at the 1st slot on the 7th layer, X12 is located at the 7th slot on the 8th layer, and the span from X12 to A13 is 5;

[0043] A14 is located at the 13th slot on the 7th layer, X14 is located at the 19th slot on the 8th layer, A15 is located at the 25th slot on the 7th layer, X15 is located at the 31st slot on the 8th layer, A16 is located at the 37th slot on the 7th layer, X16 is located at the 43rd slot on the 8th layer, and the span of the welding ends is 6 for all

[0044] AA1 is located at the 48th slot on the 1st layer, XX1 is located at the 6th slot on the 2nd layer. For all the input and output sides of the second parallel branch of the A phase, they are adjacent in slot number, the same in layer number, and the same in coil winding direction as those of the first parallel branch;

[0045] AAAA1 is located at the 1st slot on the 8th layer, XXXX1 is located at the 43rd slot on the 7th layer. AAAA1 and A1 are symmetrically distributed in the slot and have opposite coil winding directions. For all the input and output sides of the third parallel branch of the A phase, they are adjacent in slot number, the same in layer number, and the same in coil winding direction as those of the fourth parallel branch;

[0046] Such as Figure 4 , the A-phase winding 3 has 4 input terminals. The first input terminal 4 is A1, the second input terminal 5 is AA1, the third input terminal 6 is AAA1, the fourth input terminal 7 is AAAA1, and 4 output terminals. The first output terminal 8 is X1, the second output terminal 9 is XX1, the third output terminal 10 is XXX1, the fourth output terminal 11 is XXXX1. The 4 output terminals are conductively welded to represent 4-way parallel connection; if X1 is connected in series with AAA1 and XX1 is connected in series with AAAA1, then the A-phase winding becomes 2-way parallel connection; on this basis, if XXX1 is connected in series with AA1, then the A-phase winding becomes 1-way series connection.

[0047] The above embodiments only take the U-phase winding as an example. Similarly, the arrangements of the V-phase winding and the W-phase winding also follow the rules of the above U-phase winding.

[0048] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art can make modifications to the present invention without departing from the spirit of the present invention, and such modifications fall within the protection scope of the present invention.

Claims

1. A double-layer flat wire winding structure of an electric machine, comprising a stator core and a three-phase flat wire winding installed in the stator core, characterized in that, An insulating paper is provided between the stator core and the flat wire winding. The stator core is provided with Z slots, where Z is a multiple of 12. The number of slots per pole per phase of the stator core is set to q, and q is equal to 2. Each slot of the stator core contains i flat conductors. The number of poles of the three-phase flat wire winding is 2P. Each phase of the three-phase flat wire winding is provided with j parallel circuits, and each parallel branch is composed of W hairpin flat conductors, and W = Zi / 6j; all the hairpin flat conductors are inserted from one end of the stator core, and the input side and the output side of each flat conductor are embedded in adjacent layers and are separated by K slots. That is, the input side of the first hairpin flat conductor is embedded in the first layer of the first slot of the stator core, and the output side of the first hairpin flat conductor is embedded in the second layer of the (K + 1)-th slot of the stator core. The input side of the second hairpin flat conductor is embedded in the first layer of the second slot of the stator core, and the output side of the second hairpin flat conductor is embedded in the second layer of the (K + 2)-th slot of the stator core, and so on. After embedding layers 1 and 2, embed layers 3 and 4, where K = Z / 2P and q = Z / 3*2P, so that the same-phase winding structure is in the odd-numbered slots and the two-phase winding structure is in the even-numbered slots. The span from the input side to the output side of the welding end is changed by changing the bending angle of the hairpin flat conductor at the welding end; each parallel branch includes a full-pitch wave winding coil with a span of K, a short-pitch layer-changing wave winding coil with a span of K - 1, a long-pitch layer-changing wave winding coil with a span of K + 2, and also includes a short-pitch transposed wave winding coil with a span of K - 1. By layer-changing and transposing, each phase winding forms a short-pitch winding. The number of all input sides and output sides of each parallel branch embedded on different layers is exactly the same. Therefore, H is determined as the basis for judging whether each parallel branch has a transposed coil, and H = 2W / ij, and H is an integer. When H is equal to 1, each parallel branch undergoes layer-changing once every P coils, and a total of i / 2 - 1 times of layer-changing are performed, and there is no transposed coil. When H is greater than 1, each parallel branch undergoes transposing once every P coils and layer-changing once every 2P coils.

2. The double-layer flat wire winding structure of the motor according to claim 1, characterized in that: When the number of parallel branches is 2, the winding directions of the two parallel branches in each phase are opposite, the layers of the input side and the output side are opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

3. The double-layer flat wire winding structure of the motor according to claim 1, characterized in that: When the number of parallel branches is 4, the slots of the first and second branches in each phase are adjacent, the winding directions are the same, and the layers are the same. The slots of the third and fourth branches are adjacent, the winding directions are the same, and the layers are the same. The winding directions of the first and fourth branches are opposite, the layers of the input side and the output side are opposite, and the input sides of the first coils of the two branches are respectively located in the first layer and the last layer of the same slot.

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