A standard phase belt integer slot short pitch winding symmetrical 4 branch connection method

Abstract

The application discloses a standard phase belt integer slot short-pitch lap winding symmetrical 4-branch connection method, which comprises the following steps: 1) dividing positive and negative phase belts, and dividing p-pole pairs into j normal pole pairs and k special pole pairs; 2) connecting coils under the j normal pole pairs according to normal winding pitch y1; 3) performing phase-to-phase exchange on lower-layer coil edges under the k special pole pairs; and 4) recombining the upper and lower-layer coil edges under the k special pole pairs and constructing winding branches. The winding formed by the method of phase-to-phase exchange of the lower-layer coil edges can weaken high-order harmonics, the branches of each phase are completely symmetrical in electric potential and magnetic potential, and there is no circulating current between the parallel branches; the three-phase branches are also completely symmetrical; the connection problem of the short-pitch lap winding symmetrical 4-branch is solved, the advantages of the lap winding are still embodied, the copper consumption of the motor winding is significantly reduced, and the theoretical limitation that the short-pitch symmetrical 4-branch winding cannot be connected under the odd number of pole pairs is broken through.

Description

Technical Field

[0001] This invention relates to the field of three-phase AC motor winding technology, specifically to a wiring method for a symmetrical four-branch short-pitch lap winding of an integer slot standard phase band when the number of pole pairs in a motor is odd. Background Technology

[0002] Pumped storage generators use generator motors with high speeds and relatively few poles. When the number of slots q per pole and phase is large, using short-pitch lap windings not only effectively reduces high-order harmonics, but also significantly reduces copper usage compared to full-pitch lap windings due to the short-pitch y1 (y1 less than 3q, one pole pitch). This results in a clear economic benefit. Furthermore, generator motors with speeds of 428.6 r / min, capacities of 300–400 MVA, and voltages of 15.75–18 kV have wide application requirements. For electromagnetic schemes, the most reasonable number of parallel branches in many cases is four. However, since the number of pole pairs p=7 for this speed, a short-pitch symmetrical four-branch winding cannot be achieved according to the standard positive and negative phase band design theory. In practical applications, if full-pitch lap windings are used, they cannot effectively reduce high-order harmonics or reduce copper consumption. On the contrary, the presence of inter-pole crossover lines with a length of 3q slots between each pole makes them less economical than wave windings, thus failing to leverage the advantages of lap windings and rendering the selection of lap windings meaningless. If asymmetrical short-pitch lap windings are used, although they can reduce high-order harmonics such as the 5th and 7th harmonics, they have disadvantages such as branch circulating currents due to potential asymmetry. Summary of the Invention

[0003] To address the aforementioned shortcomings, this invention provides a wiring method for a standard phase-band integer-slot short-pitch lap winding with symmetrical 4 branches, comprising the following steps: 1) dividing the positive and negative phase bands, and dividing the p pole pair into j conventional pole pairs and k special pole pairs; 2) connecting the coils under the j conventional pole pairs according to the conventional winding pitch y1; 3) performing phase-to-phase exchange on the lower layer coil sides under the k special pole pairs; 4) recombining the upper and lower layer coil sides under the k special pole pairs to construct the winding branches. This invention, through the method of phase-to-phase exchange on the lower layer coil sides, enables the winding to weaken higher harmonics, and the branches of each phase are completely symmetrical in terms of electromotive force and magnetomotive force, with no circulating current between parallel branches; the three-phase branches are also completely symmetrical; it solves the wiring problem of symmetrical 4 branches of short-pitch lap winding, allowing the advantages of lap winding to still be reflected, and also breaking through the theoretical limitation that short-pitch symmetrical 4-branch windings cannot be connected under an odd number of pole pairs.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A wiring method for a standard phase-band integer-slot short-pitch lap winding with symmetrical four branches has the following electrical characteristics:

[0006] The number of motor phases m = 3, the number of motor pole pairs p is odd, the number of motor slots is Z, the number of slots per pole per phase q = Z / (2pm) is an integer and an even number, the electrical short pitch of the winding is s slots, s is an integer less than q, the winding pitch y1 = 3q-s, and the winding short pitch ratio β = 1-s / (3q).

[0007] Under the above electrical characteristics, the wiring method includes the following steps:

[0008] Step S1: Divide the positive and negative phase bands, and divide the p pole pairs into j regular pole pairs and k special pole pairs;

[0009] Step S2: Connect the coils under j conventional pole pairs according to the conventional winding pitch y1;

[0010] Step S3: The lower coil sides under the k special pole pairs are swapped phase by phase;

[0011] Step S4: Reassemble the upper and lower coil sides under the k special pole pairs and construct the winding branches;

[0012] The winding constructed by this invention can weaken high-order harmonics. The branches of each phase are completely symmetrical in terms of electromotive force and magnetomotive force, and there is no circulating current between parallel branches. The three-phase branches are also completely symmetrical. By exchanging the side phases of the lower coil, the wiring problem of the symmetrical four-branch short-pitch lap winding is solved, so that the advantages of the lap winding can still be reflected. That is, it can effectively weaken high-order harmonics and significantly reduce the amount of copper used in the motor winding. It also breaks through the theoretical limitation that a short-pitch symmetrical four-branch winding cannot be connected under an odd number of pole pairs.

[0013] Preferably, in step S1, the p pole pairs under the standard positive and negative phase bands of the three phases are divided into j conventional pole pairs and k special pole pairs. The j pole pairs and k pole pairs are evenly spaced or symmetrically distributed in the longitudinal direction of the phase band, and the integers j and k satisfy j + k = p and j > k. Let p and k be integers, k be odd and k≤3 (k>3 will result in the lap winding being less economical than the wave winding). Since p and k are odd, j is even. In this application, j pole pair represents a conventional pole pair, k pole pair represents a special pole pair, and j and k represent the quantity.

[0014] Preferably, in step S2, the 2jq coils under the j-pole pairs of each phase's positive and negative phases are divided into 4 groups according to the pole pitch q, and then connected according to the conventional winding pitch y1. The number of coils under the j-pole pairs of each phase's positive and negative phases is 2jq. Since j is an even number, 2j contains a factor of 4, so the 2jq coils can always be divided into 4 groups according to the pole pitch (pole pitch is q).

[0015] Preferably, in step S3, the upper and lower coil sides under the k pole pair are listed with a short distance of s, and then the lower coil sides of the corresponding phase band boundary of the k pole pair are swapped phase by phase so that the upper and lower coil sides under the swapped k pole pair fall within the 60° phase band width.

[0016] Preferably, the specific process of phase-to-phase exchange in step S3 is as follows: the lower coil edge originally belonging to phase A+ is exchanged for the lower coil edge of phase B-; the lower coil edge originally belonging to phase C- is exchanged for the lower coil edge of phase A+; the lower coil edge originally belonging to phase B+ is exchanged for the lower coil edge of phase C-; the lower coil edge originally belonging to phase A- is exchanged for the lower coil edge of phase B+; the lower coil edge originally belonging to phase C+ is exchanged for the lower coil edge of phase A-; the lower coil edge originally belonging to phase B- is exchanged for the lower coil edge of phase C+, and so on, in a regular manner, the exchange between the 6 phase bands is completed. After the exchange, the upper and lower coil edges of the k pole of each phase band fall within the 60° phase band width.

[0017] Preferably, the specific process of coil reassembly in step S4 is as follows: The upper and lower coil sides under the k pole pairs of each phase's positive and negative phase bands are combined to form a new coil. The new coils are divided into 4 groups, each group occupying q slots. After phase-to-phase exchange, each phase's positive and negative phase bands under the k special pole pairs have a total of 2kq upper coil sides and 2kq lower coil sides. Since q is an even number, according to the coil group... By recombining coils according to the principle of occupying all q slots, a structure can be formed. One coil, then Each coil can be divided into 4 groups, and each group occupies q slots.

[0018] As a preferred option, the specific process of constructing the winding branch in step S4 is as follows: connect one group of coils under the j pole pair and one group of coils under the k pole pair in series in the shortest wiring manner to form one branch, and each phase forms a total of 4 branches.

[0019] Preferably, in step S4, when constructing the winding branches, if k=1, two branches are constructed separately for each phase's positive and negative phase bands, resulting in a total of four branches; if k=3, four branches are constructed jointly for each phase's positive and negative phase bands. When k=1, the k pole pair is located at the middle position in the longitudinal direction of the p pole pair, i.e. The j and k pole pairs are arranged symmetrically in the longitudinal direction of the phase band, and the winding is constructed separately by the positive and negative phase bands; when k=3, the j pole pairs are divided into (k+1)=4 groups, each group The j and k pole pairs are evenly spaced in the longitudinal direction of the phase band, and the winding is constructed by combining positive and negative phase bands.

[0020] Therefore, the advantages of this invention are: by exchanging the lower coil side phases, the resulting winding can weaken higher harmonics; the branches of each phase are completely symmetrical in terms of electromotive force and magnetomotive force; there is no circulating current between parallel branches; the three-phase branches are also completely symmetrical; the wiring problem of symmetrical four branches of short-pitch lap winding is solved, so that the advantages of lap winding are still reflected, which can effectively weaken higher harmonics and significantly reduce the amount of copper used in motor winding; and it breaks through the theoretical limitation that short-pitch symmetrical four-branch winding cannot be connected under odd number of pole pairs. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the standard phase band division under the following embodiment of the present invention: the number of pole pairs is p, the number of slots per pole per phase is q, and k=1.

[0022] Figure 2 This is a schematic diagram of the phase-to-phase exchange of the lower coil side of the k pole pairs in Embodiment 1 of the present invention, where the number of pole pairs is p, the number of slots per pole per phase is q, and k=1.

[0023] Figure 3 This is a schematic diagram of the k-pole pair (A+ phase band) recombined coil and winding branch construction in Embodiment 1 of the present invention, with the number of pole pairs p, the number of slots per pole per phase q, and k=1.

[0024] Figure 4 This is a schematic diagram of the standard phase band division under the following embodiment of the present invention: the number of pole pairs is 7, the number of slots per pole per phase is 6, and k=1.

[0025] Figure 5 This is a schematic diagram of the phase-to-phase exchange of the lower coil side of the k pole pair in Embodiment 2 of the present invention, where the number of pole pairs is 7, the number of slots per pole per phase is 6, and k=1.

[0026] Figure 6 This is a schematic diagram of the k-pole pair (A+ phase band) recombined coil and winding branch construction in Embodiment 2 of the present invention, with 7 pole pairs, 6 slots per pole per phase, and k=1.

[0027] Figure 7 This is a schematic diagram of the standard phase band division in Embodiment 3 of the present invention, where the number of pole pairs is 7, the number of slots per pole per phase is 6, and k=3.

[0028] Figure 8 This is a schematic diagram of the phase-to-phase exchange of the lower coil side of the k pole pair in Embodiment 3 of the present invention, where the number of pole pairs is 7, the number of slots per pole per phase is 6, and k=3.

[0029] Figure 9 This is a schematic diagram of the k-pole pair (A-phase band) recombined coil and winding branch construction in Embodiment 3 of the present invention, where the number of pole pairs is 7, the number of slots per pole per phase is 6, and k=3.

[0030] 1. Inter-pole connecting wire; 2. Original pitch coil; 3. New pitch coil. Detailed Implementation

[0031] The present invention will now be further described with reference to the accompanying drawings and specific embodiments.

[0032] Example 1:

[0033] The electrical features of this embodiment are: the number of pole pairs p of the motor is odd, the number of slots q per pole per phase is an integer and an even number, the double-layer lap winding, the coil is a single-turn half-frame short-pitch structure, and there are symmetrical 4 branches.

[0034] The technical theory of this embodiment is as follows: the number of motor pole pairs p is odd, the number of motor slots is Z, the number of phases m = 3, the number of slots per pole per phase q = Z / (2pm) is an integer and even number, the electrical short-pitch of the winding is taken as s, where s is an integer less than q, the winding pitch y1 = 3q - s, and the winding short-pitch ratio β = 1 - s / (3q). The wiring process is as follows: divide the p pole pairs under the standard positive and negative phase bands of the three phases into j conventional pole pairs and k special pole pairs, where the integers j and k satisfy j + k = p, j > k. Let p and k be integers, k be odd and k≤3. Since p and k are odd, j is even. The coils under the j-pole pair are connected according to the conventional coil pitch y1. The number of coils under the j-pole pair in each phase's positive and negative bands is 2jq. Since j is even, 2j contains a factor of 4, so 2j×q coils can always be divided into 4 groups according to the pole pitch q. The lower layer edges of the coils under the k special pole pairs are exchanged phase by phase, so that the lower layer edges and upper layer edges of the exchanged coils fall within the 60° phase band width. Then, each phase's positive and negative bands under the k special pole pairs have a total of 2kq upper layer coil edges and 2kq lower layer coil edges. Since q is even, according to each group of coils... By recombining coils according to the principle of occupying all q slots, a structure can be formed. One coil, then Each coil can be divided into 4 groups, with each group occupying a slot q. Connecting one group of coils under the j-pole pair and the other group under the k-pole pair in series using the shortest connection method forms one winding branch, resulting in 4 winding branches per phase. The symmetrical 4-branch winding implemented according to this invention uses the same method for calculating the distribution coefficient of the νth harmonic as in traditional methods, with the short-pitch coefficient k... pv The calculation is derived theoretically, as shown in the formula below:

[0035]

[0036] The specific process of this embodiment:

[0037] Step 1: Divide the positive and negative phase bands and determine the distribution of j and k pole pairs. For a motor with Z stator slots, 2p poles, and q slots per pole per phase, its positive and negative phase bands are as follows: Figure 1 As shown, the slot number in a standard phase band generally refers only to the upper edge of the coil. Figure 1The symbols “○”, “△”, and “□” are abbreviations of the slot numbers for phases A, C, and B, respectively. Since q is an integer, each phase's positive and negative phase bands each occupy 60° electrical degrees and q slots. The p-pair is divided into j+k-pairs, where j and k satisfy j+k = p and j > k. Let k be an integer, and k be an odd number ≤ 3. Distribute the j and k pole pairs evenly and symmetrically along the longitudinal direction of the phase band. When k = 1, the k pole pair is located at the midpoint of the longitudinal direction of the p pole pair. The j and k pole pairs are arranged symmetrically in the longitudinal direction of the phase band, and the winding is constructed separately by the positive and negative phase bands; when k=3, the j pole pairs are divided into (k+1)=4 groups, each group Each pole pair is evenly spaced along the longitudinal direction of the phase band, and the winding is constructed by combining positive and negative phase bands. The following steps are explained using k=1 as an example, such as... Figure 1 The k pole pairs are arranged at the middle position of the longitudinal direction of the phase band shown, so that the j and k pole pairs are symmetrically distributed in the longitudinal direction of the phase band.

[0038] Step 2: Perform phase-to-phase swapping of the lower coil sides below the k-pole pair. List the upper and lower coil sides below the k-pole pair with short intervals of 's', as follows: Figure 2 As shown in the diagram above, the lower coil sides of the phase band boundary are indicated by solid symbols "●, ▲, ■". The lower coil sides of the corresponding phase band boundary of the k-pole pair are swapped phase-to-phase, as shown below. Figure 2 As shown, the lower coil edges originally belonging to phase A+ are swapped to those of phase B-; the lower coil edges originally belonging to phase C- are swapped to those of phase A+; the lower coil edges originally belonging to phase B+ are swapped to those of phase C-; the lower coil edges originally belonging to phase A- are swapped to those of phase B+; the lower coil edges originally belonging to phase C+ are swapped to those of phase A-; and the lower coil edges originally belonging to phase B- are swapped to those of phase C+. This process is repeated systematically across the six phases. The result after the swaps is as follows: Figure 2 The solid markings "●, ▲, ■" in the diagram below indicate that after the exchange, the upper and lower coil edges below the k-pole pair of each phase band fall within the 60° phase band width (within the q-slot).

[0039] Step 3: Reassemble the coils and construct winding branches by alternating the upper and lower coil sides with the k-pole facing downwards. The upper and lower coil sides with the k-pole facing downwards are arranged according to... Figure 3 The diagram on the right shows q coils, which are divided into two groups, as follows: Figure 3 The right-hand diagram shows the solid lines (corresponding to the new pitch coil 3) and dashed lines (corresponding to the original pitch coil 2), indicating each group of coils. Each must occupy q slots. The method for constructing a 2-branch A+ phase band is as follows: Figure 3 As shown in the left figure, the j-pole pairs are divided into two equal parts, and the continuous... The coils of the k-pole pair are connected with normal pitch and then connected in series with inter-pole connecting wire 1, and then connected to the coils of the k-pole pair. One coil connected in series forms one winding branch, and the A+ phase band can form two winding branches. Similarly, the A- phase band, along with the A+ phase band, forms a total of four winding branches for phase A.

[0040] In this embodiment, the four branch windings are completely symmetrical with respect to the three phases, and the potentials of the four branches are also completely symmetrical and balanced for each phase, so there is no circulating current between the parallel branches.

[0041] Example 2:

[0042] Taking a 300MW-class generator motor with a voltage level of 15.75-18kV and a pole number of 2p=14, which is common in the pumped storage field, as an example, the specific implementation method for achieving symmetrical 4-branch number when using a standard positive and negative phase band design for short-pitch lap windings is as follows.

[0043] The special pole pair number k=1, the positive (or negative) phase bands are used to construct the winding branch separately.

[0044] The motor has 3 phases (m), 14 poles (2p), and 7 pole pairs (p). If the number of slots is Z = 252, then the number of slots per pole per phase is... Take the electrical short pitch s = 3, and the winding structural pitch y1 = 3q - s = 3 × 6 - 3 = 15, then the short pitch ratio is... It can simultaneously reduce the 5th and 7th harmonics.

[0045] The specific process of this embodiment:

[0046] Step 1: Draw the positive and negative phase band block diagrams, such as... Figure 4 As shown, the phase band block diagram represents the upper layer side slot number of the coil; determine the distribution positions of the j and k pole pairs, k=1, and arrange the k pole pair in the middle of the first slot. Polar position, j = pk = 7 - 1 = 6, To satisfy the integer requirement, divide the j-pole pair into two symmetrical positions above and below the k-pole pair, such as... Figure 4 As shown;

[0047] Step 2: Perform phase-to-phase exchange on the lower coil sides under the k-pole pair. List the slot numbers of all upper and lower coil sides under the k-pole pair (i.e., the 4th pole pair) according to s=3, such as... Figure 5 As shown in the diagram above, the slot number relationship between the upper and lower coil sides is: lower side slot number = upper side slot number + y1. The slot number position is offset from the upper side slot number by s slot positions. Since y1 = 3q - s, and s is preceded by a minus sign, the position is shifted forward (left) by s = 3 slot positions. After inter-phase exchange of the lower side slot numbers at the phase band boundary, the phase band distribution below the k-pole pair is as follows. Figure 5 As shown in the figure below, the upper and lower coil sides of this pole pair all fall into the q slot.

[0048] Step 3: Combine the upper and lower coil sides under the k-pole pair (i.e., the 4th pole pair) to form a new coil and group them, then connect them in series with the grouped coils under the j-pole pair to form a winding branch. Since k=1, each phase band has two branches constructed separately. Specifically, taking the A+ phase band as an example, the upper sides of slots 109, 110, and 111 under the 4th pole pair and the lower sides of slots 130, 131, and 132 respectively form three new pitch coils 3, as follows. Figure 6 As shown by the diagonal dashed lines in the left diagram, these three coils are all occupied by coil sides in slots 1# to 6#, grouped together, and connected in series with the coils under pole pairs 1, 2, and 3 to form the first winding branch, as shown below. Figure 6 As shown in the right-hand diagram; similarly, the upper edges of slots 112, 113, and 114 and the lower edges of slots 127, 128, and 129 respectively form three original pitch coils 2, as shown in the diagram. Figure 6 As shown by the diagonal solid lines in the left diagram, these three coils are all occupied by coil sides in slots 1# to 6#, grouped together, and connected in series with the coils under pole pairs 5, 6, and 7 to form the second winding branch, as shown below. Figure 6 As shown in the diagram on the right, phase A+ forms 2 branches, and phase A- forms 2 branches in the same pattern, so phase A forms a total of 4 branches.

[0049] In this embodiment, the winding factors for the 5th and 7th harmonics are only 6% and 5% of those for the fundamental wave, respectively.

[0050] Example 3:

[0051] Taking a 300MW-class generator motor with a voltage level of 15.75-18kV and a pole number of 2p=14, which is common in the pumped storage field, as an example, the specific implementation method for achieving symmetrical 4-branch number when using a standard positive and negative phase band design for short-pitch lap windings is as follows.

[0052] With a special pole pair number k=3, the positive and negative phase bands jointly construct the winding branch.

[0053] The motor has 3 phases (m), 14 poles (2p), and 7 pole pairs (p). If the number of slots is Z = 252, then the number of slots per pole per phase is... Take the electrical short pitch s = 3, and the winding structural pitch y1 = 3q - s = 3 × 6 - 3 = 15, then the short pitch ratio is... It can simultaneously reduce the 5th and 7th harmonics.

[0054] The specific process of this embodiment:

[0055] Step 1: Draw the positive and negative phase band block diagrams, such as... Figure 7 As shown, the phase band block diagram represents the upper layer side slot number of the coil; to determine the distribution positions of pole pairs j and k, if k = 3, then j = 4. To satisfy the integer requirement, divide the j-pole pairs into four equal parts, with each pole pair and each k-pole pair evenly spaced along the longitudinal direction of the phase band, as follows: Figure 7 The shaded pole pairs shown are the k-pole pairs;

[0056] Step 2: Perform phase-to-phase exchange on the lower coil sides under each k-pole pair. List the slot numbers of the upper and lower coil sides for each phase band under each k-pole pair (i.e., the 2nd, 4th, and 6th pole pairs) according to s=3, such as... Figure 8 As shown in the figure above, the relationship between the slot numbers of the upper and lower coil sides is: lower side slot number = upper side slot number + y1. The slot number position is offset from the upper side slot number by s slots. Since y1 = 3q - s, and there is a minus sign before s, the position is offset forward (left) by s = 3 slots. Figure 8 The diagram uses the second pole pair as an example to illustrate the principle of phase-to-phase exchange of the lower layer edges of the coils under each k-pole pair. After the phase-to-phase exchange of the slot numbers on the lower layer edges of the phase band boundaries, the phase band distribution under each k-pole pair is as follows: Figure 8 As shown in the figure below, the upper and lower coil sides of each k pole pair all fall into the q slot.

[0057] Step 3: Combine the upper and lower coil sides of each k-pole pair (i.e., pole pairs 2, 4, and 6) to form a new coil, and connect it in series with the coil under the j-pole pair to form a winding branch. Since k = 3, the positive and negative phase bands of each phase jointly construct 4 branches. The specific formation of the new coil under each k-pole pair is illustrated using the upper side of slots 37, 38, 39, 40, 41, and 42 and the lower side of slots 55, 56, 57, 58, 59, and 60 under the 2nd pole pair of phase A+ as an example. The new coil is formed as follows: "Upper side of slot 37 – Lower side of slot 58", "Upper 38 – Lower 59", "Upper 39 – Lower 60", "Upper 40 – Lower 55", "Upper 41 – Lower 56", and "Upper 42 – Lower 57". Figure 9 As shown by the diagonal lines in the diagram above. The three diagonally dashed coils are the new pitch coil 3; when connected in series, both the upper and lower layers of coils occupy slot q. The three diagonally solid coils are the original pitch coil 2; when connected in series, both the upper and lower layers of coils occupy slot q. Figure 9 The diagram below shows the wiring for phase A. Phases A+ and A- together form four branches. Each branch contains a coil with two pole pitches under the j-pole pair and a coil with 1.5 pole pitches under the k-pole pair. Since the four branches occupy the same number of coil sides in the same slot, their potentials are completely symmetrical. In Figure 9, the slot numbers refer to the upper-layer slot numbers; the shaded slot numbers are the new pitch coil slot numbers under each k-pole pair, and the other slot numbers are the original pitch coil slot numbers.

[0058] In this embodiment, the winding coefficients of the 5th and 7th harmonics are only 10% and 8% of those of the fundamental wave, respectively.

[0059] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch circuit, the electrical characteristics of which are: motor phase number m=3, motor pole pair number p is odd, motor slot number is Z, slot number per pole per phase q=Z / (2pm) is an integer and even number, the electrical short pitch of the winding is s slot, s is an integer less than q, winding pitch y1=3q-s, winding short pitch ratio β=1-s / (3q); Its features are, Under the above electrical characteristics, the wiring method includes the following steps: Step S1: Divide the positive and negative phase bands, and divide the p pole pairs into j regular pole pairs and k special pole pairs. The integers j and k satisfy j+k=p, j>k, j / (k+1) is an integer, k is an odd number and k≤3; Step S2: Connect the coils under j conventional pole pairs according to the conventional winding pitch y1; Step S3: The lower coil sides under the k special pole pairs are swapped in phases, and the upper and lower coil sides under the swapped k pole pairs fall within the 60° phase band width; Step S4: Reassemble the upper and lower coil sides under the k special pole pairs and construct winding branches. Divide the new coils into 4 groups, each group occupying q slots. Connect the coil group under the j pole pair and the coil group under the k pole pair in series in the shortest wiring manner to form a branch. Each phase forms a total of 4 branches.

2. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1, characterized in that, In step S1, the j-pole pairs and k-pole pairs are evenly spaced or symmetrically distributed in the longitudinal direction of the phase band.

3. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1, characterized in that, In step S2, the 2jq coils under the j pole pairs of each phase positive and negative phase are divided into 4 groups according to the pole pitch q, and then connected according to the conventional winding pitch y1.

4. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1, characterized in that, In step S3, the upper and lower coil sides below the k pole pair are listed with a short distance of s, and then the lower coil sides of the corresponding phase band boundary of the k pole pair are swapped phase by phase.

5. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1 or 4, characterized in that, The specific process of phase-to-phase exchange in step S3 is as follows: the lower coil edge originally belonging to phase A+ is exchanged for the lower coil edge of phase B-; the lower coil edge originally belonging to phase C- is exchanged for the lower coil edge of phase A+; the lower coil edge originally belonging to phase B+ is exchanged for the lower coil edge of phase C-; the lower coil edge originally belonging to phase A- is exchanged for the lower coil edge of phase B+; the lower coil edge originally belonging to phase C+ is exchanged for the lower coil edge of phase A-; the lower coil edge originally belonging to phase B- is exchanged for the lower coil edge of phase C+. The exchange between the six phases is completed in a regular manner. After the exchange, the upper and lower coil edges of the k pole of each phase fall within the 60° phase width.

6. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1, characterized in that, When constructing the winding branches in step S4, when k=1, each phase positive and negative phase band constructs 2 branches separately, and the positive and negative phase bands together constitute 4 branches.

7. The wiring method for a standard phase-band integer slot short-pitch lap winding symmetrical 4-branch according to claim 1, characterized in that, When constructing the winding branches in step S4, when k=3, each phase's positive and negative phases jointly construct 4 branches.

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