A method for designing a front and back equal-pitch fractional-slot wave winding

Abstract

The application discloses a front-rear equal-pitch fractional-slot wave winding design method, and solves the problems of uneven motor winding front-rear structure pitch, uneven motor two-end insulation space and large difference between two-end electric power in the prior art. The method comprises the following steps: drawing a Tinkler slot chart according to motor slot number Z, motor pole number 2p and slot number q per pole per phase; connecting slot numbers with mutual difference H pitch as phase belt lines in the Tinkler slot chart; sequentially dividing phase belts of three phases A, B and C along the phase belt lines; drawing two phase belts of each phase along the phase belt lines, wherein the two phase belts are mutually offset by s slots and have a width of N; and each two phase belts of each phase which are mutually short-pitched form a winding loop. The Tinkler slot chart is used to replace the original block diagram, the same pitch is used as a prerequisite for design, the conductors for forming coils are used as design objects, and the design is performed from the essence of electrical short pitch, i.e., the formation of short pitch of phase belts. The motor two-end insulation space is balanced, and the end electric power is balanced.

Description

Technical Field

[0001] This invention relates to the field of motor winding technology, and in particular to a design method for a fractional slot wave winding with equal pitch at both ends. Background Technology

[0002] In the field of hydro-generators, three-phase motors, due to their large number of poles and stator slots, present complex wave winding designs when using fractional slots. The industry commonly employs a method of creating a phase band block diagram using a "standard phase band coil group cycle sequence." To reduce 5th and 7th harmonics, short-pitch windings are generally used in the wave windings, meaning the first pitch y1 of the wave winding is not equal to the second pitch y2. Specifically, for a motor with 3 phases (m=3), 2p poles, and Z slots, the number of slots per pole per phase is expressed as q=Z / (2pm)=b+c / d, a fractional slot winding. Slot numbers 1 to Z are filled into a 6q×p block diagram, and then the slot numbers are sequentially divided into positive and negative phase bands A, B, and C according to a cycle sequence containing "b" and "b+1". + C - B - A - C + B - There are a total of 6×60° (electric angle) phase bands. The slot number in each phase band generally only represents the upper side of the coil in the slot. The slot number of the lower side of the coil is agreed to be y1 slots away from the upper side by the short pitch ratio. The slot number of the lower side is not reflected in the block diagram. y1 is called the first pitch of the winding.

[0003] Taking a motor with Z=27, 2p=4, and m=3 as an example, the number of slots per pole per phase is q=27 / (4×3)=2+1 / 4=b+c / d, that is, b=2, c=1, d=4; 6q=13.5≈14. The cycle number sequence of the standard phase band coil group contains c "b+1" and dc "b", that is, 1 "3" and 3 "2". Taking the cycle number sequence "3222", the block diagram and the division of the 6-phase band are as follows. Figure 1a As shown, the block diagram has 6q×p = 14×2 cells. Slots 1 to 27 are filled in sequentially and then distributed to phases A, C, and B in a cyclical sequence "3222" to form a 6-phase band. The positive and negative phase bands of phase A are shown below. Figure 1a For the filler slots, when the combined pitch y = y1 + y2 ≈ 6q = 14, the first pitch y1 = 6 is chosen, and its short-pitch ratio β = y1 / 3q = 6 / 6.75 ≈ 0.889 is most suitable. y2 = y - y1 = 8. Therefore, the coil connection method is as follows: Figure 1c That is, located at 1 # Slot 1 # The upper edge of the coil is connected to the coil located at 7 via a pitch of y1 = 6. # Slot 1 #The lower edge of the coil is then connected to the next coil, located at 15, via a pitch of y2 = 8. # The 15th slot # The upper edge of the coil, sequentially... Figure 1b After connecting all the coils, the complete wiring diagram is as follows: Figure 1d As shown. In this traditional method of designing wave windings, the short-pitch ratio β = y1 / (3q) = 0.8~0.9, i.e., y1 = (0.8~0.9)3q. The combined coil pitch of the wave winding is y = y1 + y2 ≈ 6q. Therefore, the difference in coil pitch between the front and rear sections of the winding is: y2 - y1 ≈ 6q - 2y1 = 3q[2 - 2(0.8~0.9)] = (20~40%) × 3q = (20~40%) pole pitch. This means that the coil ends at both ends of the motor are of different lengths. For bulb-type hydro generators, under conditions of low speed, large number of poles 2p, and small q, the short-pitch side has insufficient insulation space, while the other end is longer and has ample insulation space, resulting in an imbalance in insulation space at both ends of the motor. For large-capacity, high-speed generator-motors, under conditions of small number of poles 2p and large number of slots per pole per phase q, there is a significant difference in electrodynamic force at both ends. This drawback is caused by the fact that the first pitch y1 of the wave winding is not equal to the second pitch y2. Moreover, this drawback will always exist whenever a short-pitch winding must be selected in order to weaken the 5th and 7th harmonics. Summary of the Invention

[0004] This invention primarily addresses the problem in existing technologies where the front and rear structural pitches of motor windings are unequal, resulting in uneven insulation space at both ends of the motor and a large difference in electrodynamic forces at the two ends. It provides a design method for fractional slot wave windings with equal front and rear pitches.

[0005] The above-mentioned technical problem of the present invention is mainly solved by the following technical solution: a design method for a fractional slot wave winding with equal pitch at both ends, comprising the following steps:

[0006] The technical theory is as follows: Based on the number of motor slots Z, the number of motor poles 2p, and the number of slots per pole per phase q, draw the Tinclair slot layout diagram. In the Tinclair slot layout diagram, connect the slot numbers that are different by a pitch H to form the phase band line. Divide the phase bands of the three phases A, B, and C sequentially along the phase band line. For each phase, draw two phase bands with a width of N and offset from each other by a slot of s along the phase band line. Each pair of phase bands with a short pitch to each other forms the winding circuit.

[0007] This invention replaces the original 6×60° block diagram with a 3×60° Tinker slot layout diagram, takes the same front and rear structural pitch as a design prerequisite, focuses on the conductors that make up the coil as the design object, and starts from the essence of electrical short pitch, namely the short pitch formed by phase bands. This ensures that the insulation space at both ends of the motor and the electrodynamic phase are balanced.

[0008] As a preferred embodiment, the drawing of the Tinclair trench location map includes:

[0009] Based on the number of pole pairs p, the number of slots Z, and the number of phases m = 3, the number of slots per pole per phase q = Z / (2pm) = b + c / d = (bd + c) / d, where b, c, and d are positive integers, and c / d is an irreducible fraction. Draw a 3×60° Tinclair slot layout diagram according to p, Z, and q; where 60° is the electrical angle.

[0010] The number of slots per pole is defined as 3q = H ± e / d, where H is the integer closest to 3q, e / d is the smallest irreducible fraction, and H is defined as the front and rear structural pitch of the winding.

[0011] As a preferred embodiment, the phase band division specifically includes:

[0012] In the Tinclair slot layout diagram, a phase band is constructed along the slots with a slot number difference of H. The phase band width N of each phase is equal to the number of conductors continuously connected with a pitch of H at a 60° electrical angle. The phase band width N = (bd + c) / e, where N is an integer or a fraction of 1 / 2. Two phase bands with a phase band width of N but offset from each other by slot s are divided in the Tinclair slot layout diagram to form a winding loop. s is the electrical short pitch of the short-pitch winding, s = n × H, where n is an integer. When n = 0, the winding is an electrically full-pitch winding; when n ≠ 0, it is an electrically short-pitch winding. According to this scheme, each phase in the Tinclair slot layout diagram can be divided into one or more pairs of phase bands with short pitches to form a loop. Multiple pairs of loops are connected in series or parallel to form winding branches. In this design of the wave winding, the first structural pitch y1 and the second structural pitch y2 are always equal to H, and the short pitch of the winding is determined by the phase band offset s. The distribution coefficient and short pitch coefficient of the νth harmonic of the winding are theoretically derived as follows:

[0013] Distribution coefficient

[0014] Short distance coefficient

[0015] As a preferred embodiment, the winding circuit specifically comprises:

[0016] The upper and lower conductors of each phase band are connected in series with a pitch of H, and the first and last conductors of the two phase bands are connected with jumpers to form a winding circuit.

[0017] As a preferred solution, the phase band wiring is optimized according to the phase band width N, including:

[0018] When N is odd, the upper and lower conductors of the slot where the tail end of the phase band in each phase is located in other phases are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

[0019] As a preferred solution, the phase band wiring is optimized according to the phase band width N, including:

[0020] When N is a fraction of 1 / 2, the phase band widths are set to N1 = N + 1 / 2 and N2 = N - 1 / 2. The first phase band of A, C, and B is cyclically divided in the Tinker Tunnel Diagram according to the alternating pattern of N1 and N2. A short-pitch phase band is set to form a short distance with the first phase band, and the short-pitch offset is s1. Starting from the short-pitch phase band, the short-pitch phase bands of A, C, and B are cyclically divided according to the alternating pattern of N2 and N1.

[0021] The upper and lower conductors of the slot where the phase band in each phase is located are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

[0022] As a preferred option, the front and rear structural pitches H of the winding are equal.

[0023] Therefore, the advantages of this invention are: it uses a Tinker slot diagram instead of the original block diagram, takes the same front and rear structural pitch as a design prerequisite, focuses on the conductors that make up the coil as the design object, and designs from the essence of electrical short pitch, namely, the short pitch formed by phase bands. This ensures that the insulation space at both ends of the motor is balanced and the electrodynamic force is balanced. Attached Figure Description

[0024] Figure 1a This is an example of a motor phase block diagram in the background art of this invention;

[0025] Figure 1b This is an example of a motor wiring diagram in the background section of the present invention;

[0026] Figure 1c This is a schematic diagram illustrating the wiring pitch of a motor wave winding in the background art of this invention;

[0027] Figure 1d This is an example of a motor wiring diagram in the background art of this invention;

[0028] Figure 2 This is a schematic diagram of the phase zone division of the Tinkert slot map of the present invention;

[0029] Figure 3a This is a schematic diagram of the Tinkert slot location and phase zone division in Embodiment 2 of the present invention;

[0030] Figure 3b This is a diagram showing the phase band conductor connection in Embodiment 2 of the present invention;

[0031] Figure 3c This is a schematic diagram of the exchange of conductors in the same slot in Embodiment 2 of the present invention;

[0032] Figure 3d This is a schematic diagram of the large and small phase band wiring and the wiring unfolded in Embodiment 2 of the present invention;

[0033] Figure 4aThis is a schematic diagram of the Tinkert slot location and phase zone division in Embodiment 3 of the present invention;

[0034] Figure 4b This is a schematic diagram of the formation of large and small phase bands after the conductors are exchanged in Embodiment 3 of the present invention;

[0035] Figure 4c This is a schematic diagram of the winding connection in Embodiment 3 of the present invention;

[0036] Figure 5a This is a schematic diagram of the Tinkert slot location diagram and phase zone division in Embodiment 4 of the present invention;

[0037] Figure 5b This is a schematic diagram of the winding connection in Embodiment 4 of the present invention;

[0038] Figure 6a This is a schematic diagram of the Tinkert slot location and phase zone division in Embodiment 5 of the present invention;

[0039] Figure 6b This is a schematic diagram of the formation of large and small phase bands after the conductors are exchanged in Embodiment 5 of the present invention;

[0040] Figure 6c This is a schematic diagram of the winding connection in Embodiment 5 of the present invention. Detailed Implementation

[0041] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0042] Example 1:

[0043] This embodiment presents a method for designing a fractional slot wave winding with equal pitch at both ends, comprising the following steps:

[0044] The technical theory is as follows: Based on the number of motor slots Z, the number of motor poles 2p, and the number of slots per pole per phase q, draw the Tinclair slot layout diagram. In the Tinclair slot layout diagram, connect the slot numbers that are different by a pitch H to form the phase band line. Divide the phase bands of the three phases A, B, and C sequentially along the phase band line. For each phase, draw two phase bands with a width of N and offset from each other by a slot of s along the phase band line. Each pair of phase bands with a short pitch to each other forms the winding circuit.

[0045] The drawing of the Tinclair trench location diagram includes:

[0046] like Figure 2 As shown, based on the number of pole pairs p, the number of slots Z, and the number of phases m = 3, the number of slots per pole per phase q = Z / (2pm) = b + c / d = (bd + c) / d, where b, c, and d are positive integers, and c / d is an irreducible fraction; the front and rear structural pitches H of the winding are equal, that is, the first pitch of the winding is equal to the second pitch of the winding.

[0047] Define the number of slots per pole as 3q = 3(bd+c) / d = H ± e / d, where H is the integer closest to 3q, e is the smallest integer that makes H the closest integer to 3q, e / d is the smallest irreducible fraction, and H is defined as the front and rear structural pitch of the winding.

[0048] Draw a 3×60° Tinclair tank location diagram according to p, Z, and q.

[0049] Phase band division specifically includes:

[0050] In the Tinclair slot layout diagram, phase bands are constructed along slots with a slot number difference of H. The phase band width N of each phase is equal to the number of conductors continuously connected with a pitch of H at a 60° electrical angle. The phase band width N = (bd + c) / e, where N is an integer or a fraction of 1 / 2. Two phase bands with a phase band width of N and offset from each other by slot s are divided in the Tinclair slot layout diagram to form a winding loop. s is the electrical short pitch of the short-pitch winding, s = n × H, where n is an integer. When n = 0, the winding is an electrically full-pitch winding; when n ≠ 0, it is an electrically short-pitch winding. In the Tinclair slot layout diagram, each phase can be divided into one or more pairs of phase bands with short pitches to form a loop. Multiple pairs of loops are connected in series or parallel to form winding branches. Designing the wave winding in this way, its first structural pitch y1 and second structural pitch y2 are always equal to H, and the short pitch of the winding is determined by the phase band offset s. The distribution coefficient and short pitch coefficient of the νth harmonic of the winding are theoretically derived as follows:

[0051] Distribution coefficient

[0052] Short distance coefficient

[0053] The winding circuit specifically includes:

[0054] The slots of each phase band are connected in series with the upper and lower conductors at a pitch of H, and the first and last conductors of the two phase bands are connected with jumpers to form a winding circuit. Furthermore, the phase band wiring is optimized according to the phase band width N, including:

[0055] When N is odd, the upper and lower conductors of the slot where the tail end of the phase band in each phase is located are swapped. The phase bands after the conductor swap are connected to form large and small phase bands. The electrical short-pitch ratio of the winding is β = 1 - n / (3N). When n = 0, the winding is an electrical full-pitch winding; when n ≠ 0, it is an electrical short-pitch winding.

[0056] When N is a fraction of 1 / 2, the phase band widths are set to N1 = N + 1 / 2 and N2 = N - 1 / 2. The first phase band of A, C, and B is cyclically divided in the Tinker Tunnel Diagram according to the alternating pattern of N1 and N2. A short-pitch phase band is set to form a short distance with the first phase band, and the short-pitch offset is s1. Starting from the short-pitch phase band, the short-pitch phase bands of A, C, and B are cyclically divided according to the alternating pattern of N2 and N1.

[0057] The upper and lower conductors of the slot where the phase band in each phase is located are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

[0058] Example 2:

[0059] This embodiment describes a design method for a fractional slot wave winding with equal pitch at both ends, using a motor with Z=27 slots, 2p=4 poles, and m=3 phases as an example. The basic parameters of the motor in this embodiment are exactly the same as those of the motor exemplified in the background art, serving as a comparison between the design method of this invention and the traditional standard phase band design method.

[0060] Number of slots per pole per phase q=Z / (2pm)=2+1 / 4=b+c / d, b=2、c=1、d=4, 3q=6+3 / 4=7-1 / 4=He / d, that is, the front and rear structural pitch H=7、e=1, the phase bandwidth N=(bd+c) / e=(2×4+1) / 1=9.

[0061] Drawing Tinclair tank location diagram as follows Figure 3a As shown, the phase band division includes the first phase band of phase A, as shown below. Figure 3a The solid lines in the diagram, taking slot 1 as the first slot number, follow the sequence 1→8→15→22→2 ＝29-27 →9→16→23→3 (9 slots in total); the second phase band of phase A is as follows Figure 3a The dotted line in the diagram represents a short offset s = n × H = 3 × 7 = 21, meaning starting from slot "1+21", the sequence is 22→2→9→16→23→3→10→17→24, a total of 9 slots. Figure 3a The slot layout diagram of the repeating section clearly shows the electrical short-pitch characteristics of the two phase bands. After the phase band of phase A is determined, the phase bands of phases C and B can be drawn sequentially along the phase band line. The short-pitch offset s = n × H = 3 × 7 = 21, that is, n = 3, then the short-pitch ratio of the winding β = 1 - n / (3N) = 1 - 3 / (3 × 9) = 0.889.

[0062] Composing the winding circuit: Slot numbers within each phase band are used alternately; upper and lower conductors are connected with a pitch of H=7; conductors between phase bands are connected with jumpers, such as... Figure 3b As shown, the construction method of phase A circuit is given. Since the phase band width N=9 is an odd number, and the jumper wires and leads are present at both ends of the motor, the phase band is made into a large and small phase band by exchanging the upper and lower conductors in the same slot, as shown. Figure 3c As shown, by swapping the upper and lower conductors of slots 3 (=n) at the outer tail end of phase A, i.e., slots 10, 17, and 24, a large phase band (solid line portion) and a small phase band (dashed line portion) are formed in the figure. The electrical performance of the phase band remains unchanged after the conductor swap, and the wiring is optimized. Its winding wiring diagram and wiring unfolded diagram are shown below. Figure 3d As shown, it can be clearly seen that the winding in this embodiment has the characteristic that the front and rear structural pitches H are equal.

[0063] Example 3:

[0064] This embodiment describes a design method for a fractional slot wave winding with equal pitch at the front and rear ends. Taking a bulb-type hydro generator with Z=444 slots, 2p=64 poles, and m=3 phases as an example, since this motor has a large number of poles and slots, for the sake of simplicity and clarity, it is described using half of it as a unit, that is, using an equivalent motor with 2p=64 / 2=32 poles and Z=444 / 2=222 to illustrate the specific implementation method.

[0065] The equivalent motor has the following number of slots per pole per phase: q = Z / (2pm) = 222 / (32×3) = 2 + 5 / 16 = b + c / d, i.e., b = 2, c = 5, d = 16. Then, 3q = 3(b + c / d) = 3×(2 + 5 / 16) = 6 + 15 / 16 = 7 - 1 / 16 = He / d. That is, the front and rear structural pitches of the windings are H = 7 and e = 1. The phase band width is N = (bd + c) / e = (2×16 + 5) / 1 = 37, and each phase band consists of 37 conductors.

[0066] Drawing Tinclair tank location diagram as follows Figure 4a As shown, the phase zone division includes: drawing the first phase zone line of phase A in the Tinker trench location diagram, as shown below. Figure 4a The thin solid line in the diagram represents the first phase band, which consists of the following slot numbers: 1, 8, 15, 22, (22+H), ..., 17, 24, 31, a total of 37 conductors. The second phase band, forming a short distance from these slots, is shown below. Figure 4a The thick solid line in the diagram represents the short-distance offset between the two phase bands, which is s = 17 × 7 = 119 slots. That is, the second phase band consists of the following slot numbers: 120, 127, 134, (134 + H), ..., 136, 143, 150, a total of 37 conductors. The third phase band line is as follows... Figure 3a The thin dashed line in the diagram represents a phase zone line that is identical to the first phase zone line in terms of slot location and polarity. Phase zone lines forming short distances with it include... Figure 4a The thick dashed lines in the diagram, the 3rd and 4th phase bands are constructed in the same way as the 1st and 2nd phase bands mentioned above. The number of slots with short-pitch offset for the phase bands drawn by the above method is s = 119 = 17 × 7 = n × H, n = 17. Therefore, the A phase band has an electrical short-pitch ratio of β = 1 - n / (3N) = 1 - 17 / (3 × 37) = 0.85 to weaken higher harmonics.

[0067] Since the phase width N = 37 is an odd number, to avoid the winding terminal leads being distributed at both ends of the motor, by... Figure 4b The upper and lower conductors in the slot where the tail end of the phase band is located are swapped, and the phase band after the conductor swap is formed into a large and small phase band. The electrical performance remains completely unchanged, but the wiring becomes simpler, and the terminal lead is also located at one end of the motor. Figure 4b The slot numbers contained in the phase band are organized, and its wiring diagram is as follows: Figure 4cAs shown, the slot number in the wiring diagram only represents the slot number of the upper conductor, omitting the slot number of the lower conductor. The lower conductor is defined by y1 = H = 7. The winding pitch designed in this embodiment is y1 = y2 = 7 = H, meaning the front and rear structural pitches are equal; while according to traditional design methods, the winding pitch is usually designed as y1 = 8 and y2 = 6, with unequal front and rear structural pitches.

[0068] Example 4:

[0069] This embodiment presents a design method for a fractional slot wave winding with equal pitch at both ends. Taking a bulb-type hydro generator with Z=264 slots, 2p=14 poles, and m=3 phases as an example, the number of slots per pole and per phase is q=6+2 / 7=b+c / d, i.e., b=6, c=2, d=7. 3q=3(b+c / d)=3×(6+2 / 7)=18+6 / 7=19-1 / 7=He / d, i.e., the structural pitch of the winding is H=19, e=1. The phase band width of the winding is N=(bd+c) / e=(6×7+2) / 1=44 conductors.

[0070] Drawing Tinclair tank location diagram as follows Figure 5a As shown, when dividing the phase band, the short-range offset s = 0 is taken, that is... Figure 5a The thin solid line and thick solid line represent two identical phase bands. The thin dashed line and thick dashed line represent two other identical phase bands, but they are electrically symmetrical to the former at 180°. Because each slot has two conductors, upper and lower, alternating the upper and lower conductors can independently form a configuration like... Figure 5b The four circuits shown can be connected at the same end of the motor to form four branch windings. In this embodiment, the windings have jumper wires at both ends of the motor.

[0071] Example 5:

[0072] This embodiment describes a design method for a fractional slot wave winding with equal pitch at the front and rear ends. Taking a bulb-type hydro generator with Z=252 slots, 2p=52 poles, and m=3 phases as an example, since this motor has a large number of poles and slots, for the sake of simplicity and clarity, it is described using half of it as a unit, that is, using an equivalent motor with 2p=52 / 2=26 poles and Z=252 / 2=126 to illustrate the specific implementation method.

[0073] The equivalent motor has the following number of slots per pole per phase: q = Z / (2pm) = 126 / (26×3) = 1 + 8 / 13 = b + c / d, i.e., b = 1, c = 8, d = 13. Then 3q = 3(b + c / d) = 3×(1 + 8 / 13) = 3 + 24 / 13 = 5 - 2 / 13 = He / d, i.e., the front and rear structural pitches of the winding are H = 5 and e = 2; the phase width N = (bd + c) / e = (1×13 + 8) / 2 = 10.5 ≠ integer, i.e., when N is 1 / 2.

[0074] When N is a fraction of 1 / 2, the phase band widths are set to N1 = N + 1 / 2 and N2 = N - 1 / 2. The first phase band of A, C, and B is cyclically divided in the Tinker Tunnel Diagram according to the alternating pattern of N1 and N2. A short-pitch phase band is set to form a short distance with the first phase band, and the short-pitch offset is s1. Starting from the short-pitch phase band, the short-pitch phase bands of A, C, and B are cyclically divided according to the alternating pattern of N2 and N1.

[0075] The upper and lower conductors of the slot where the phase band in each phase is located are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

[0076] Specifically, the phase band widths are set as N1 = 10.5 + 0.5 = 11 and N2 = 10.5 - 0.5 = 10. The Tinkert slot location diagram is drawn as follows: Figure 6a As shown, in the slot diagram, 1 # The slot is numbered starting from slot 1. Phase bands A, C, B, A, C, B… are drawn cyclically according to the alternation pattern N1=11, N2=10, N1=11, N2=10… The phase band obtained for phase A is as follows… Figure 6a As shown by the solid line; the phase band forming a short distance with it takes a short distance offset s1 = -25 slots, that is, the slot number of the other phase band = 1 - 25 = -24 = Z - 24 = 126 - 24 = 102 # Slot, from 102 # The grooves begin to draw phase bands A, C, B, A, C, B... in an alternating pattern of N2=10, N1=11, N2=10, N1=11... The phase band obtained for phase A is as follows... Figure 6a As shown by the dashed line. The final short-range offset of phase A is as follows. Figure 6a As shown, |s1|=25=5×5=n1×H, that is, n1=5; |s2|=30=6×5=n2×H, that is, n2=6. Then the average short-range offset n=(n1+n2) / 2=(5+6) / 2=5.5. Therefore, the short-range ratio β=1-n / 3N=1-5.5 / (3×10.5)=0.8254.

[0077] Figure 6a The phase band wiring is relatively long, and there are jumper wires at both ends of the motor. This is addressed by swapping the upper and lower conductors of the slot where the tail end of each phase band is located in another phase, and by swapping the conductors between phase bands, as well as... Figure 5b Italic font slot number, obtain Figure 6b The phase bands shown are simple to wire, with all jumper wires on one side, such as... Figure 6c As shown.

[0078] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A design method for a fractional slot wave winding with equal pitch at both ends, characterized in that... Includes the following steps: Draw a Tinclair slot layout diagram based on the number of motor slots Z, the number of motor poles 2p, and the number of slots per pole per phase q, including: Based on the number of pole pairs p, the number of slots Z, and the number of phases m, the number of slots per pole per phase q = Z / (2pm) = b + c / d = (bd + c) / d, where b, c, and d are positive integers, and c / d is an irreducible fraction. Define the number of slots per pole as 3q = H ± e / d, where H is the integer closest to 3q, e is the smallest integer that makes H the closest integer to 3q, and e / d is the smallest irreducible fraction. H is defined as the structural pitch before and after the winding. Draw a 3×60° Tinclair slot layout diagram according to p, Z, and q. In the Tinker slot diagram, slot numbers with a pitch difference of H are connected as phase band lines. The phase bands of phases A, B, and C are sequentially divided along the phase band lines. Two phase bands with a width of N and offset from each other by s slots are drawn along the phase band lines for each phase. Each pair of phase bands with a short pitch to each other form a winding loop.

2. The design method for a fractional slot wave winding with equal pitch at the front and rear ends according to claim 1, characterized in that: The drawing of the Tinclair slot map includes: Based on the number of pole pairs p, the number of slots Z, and the number of phases m=3, the number of slots per pole per phase q=Z / (2pm)=b+c / d=(bd+c) / d, where b, c, and d are positive integers, and c / d is an irreducible fraction; Define the number of slots per pole as 3q = 3(bd + c) / d = H ± e / d, where H is the integer closest to 3q, e is the smallest integer that makes H the closest integer to 3q, e / d is the smallest irreducible fraction, and H is defined as the front and rear structural pitch of the winding. Draw a 3×60° Tinclair location diagram using p, Z, and q.

3. The design method for a fractional slot wave winding with equal pitch at the front and rear ends according to claim 2, characterized in that: The phase band division specifically includes: In the Tinclair slot layout diagram, a phase band is constructed along the slots with a slot number difference of H. The phase band width N of each phase is equal to the number of conductors continuously connected with a pitch of H at a 60° electrical angle. The phase band width N = (bd + c) / e, where N is an integer or a fraction of 1 / 2. Two phase bands with a phase band width of N and offset from each other by slot s are divided in the Tinclair slot layout diagram to form a winding loop. s is the electrical short pitch of the short-pitch winding, s = n × H, where n is an integer. When n = 0, the winding is an electrical full-pitch winding; when n ≠ 0, it is an electrical short-pitch winding.

4. A method for designing a fractional slot wave winding with equal pitch at the front and rear ends according to claim 1, 2, or 3, characterized in that: The winding circuit specifically includes: The upper and lower conductors of each phase band are connected in series with a pitch of H, and the first and last conductors of the two phase bands are connected with jumpers to form a winding circuit.

5. The design method for a fractional slot wave winding with equal pitch at the front and rear ends according to claim 4, characterized in that: Optimize the wiring of the phase band according to the phase band width N, including: When N is odd, the upper and lower conductors of the slot where the tail end of the phase band in each phase is located in other phases are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

6. The design method for a fractional slot wave winding with equal pitch at the front and rear ends according to claim 4, characterized in that: Optimize the wiring of the phase band according to the phase band width N, including: When N is a 1 / 2 fraction, set the phase band width N1=N+1 / 2 and N2=N-1 / 2. In the Tinker slot map, divide the first phase band of A, C and B in an alternating pattern of N1 and N2. Set a short-pitch phase band that forms a short distance with the first phase band. The short-pitch offset is s1. Starting with the short-pitch phase band, divide the short-pitch phase band of A, C and B in an alternating pattern of N2 and N1. The upper and lower conductors of the slot where the phase band in each phase is located are swapped. The phase bands after the conductor swap are formed into large and small phase bands for wiring.

7. A method for designing a fractional slot wave winding with equal pitch at the front and rear ends according to claim 1, 2, or 3, characterized in that: The front and rear structural pitch H of the winding are equal.

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