RU2046500C1 - Fractional-slot three-phase stator winding - Google Patents

Abstract

FIELD: electrical machines. SUBSTANCE: inner and outer coils of each even-numbered group of stator winding have (1+x)·W_c and (1-x)·W_c, and turns, respectively; groups of each phase are series-connected; even-numbered groups are differentially connected relative to odd-numbered groups, where p 1, 2, 3, k 0, 1, 2.(2p-1); 2·W_c is number of turns per slot; x value is chosen from 0,45≅ x≅ 0,50 range. EFFECT: improved design. 5 dwg

Description

 The invention relates to the windings of electrical AC machines and can be used in combined electrical machines with two opposite-pole fields in the magnetic circuit.

 Known three-phase fractional windings of electrical machines of alternating current, performed two-, one- and one-two-layer of equal-step or concentric coils.

 The disadvantage of the known three-phase fractional windings is increased differential scattering, which worsens their electromagnetic parameters, which is especially manifested in electric combined AC machines.

Closest to the proposed one is a three-phase fractional winding with a pole of p = 3 and the number of grooves per pole and phase q = 2.5, made in Z = 45 grooves of 6p = 18 coil groups. Each group contains two concentric coils with groove steps and number of turns Y _n = 7, 5 and 2 W _k , W _k for odd groups, Y _n 6, 4 and W _k , W _k for even groups. Such a winding is made with three parallel branches in phases and simultaneously operates as a multiphase short-circuited for polarization p ^I 5 and three-phase for p = 3.

 The purpose of the invention is the improvement of the electromagnetic parameters of a three-phase fractional winding with a pole p and the number of grooves per pole and phase q = 2.5 by reducing the differential scattering.

The goal is achieved in that for a three-phase fractional stator winding with a pole of p and the number of grooves per pole and phase q = 2.5, made in Z = 15p grooves from K = 6p coil groups with numbers in the phases of the first, second, third, respectively 1+ 3k, 3 + 3k, 5 + 3k, containing in each group two concentric coils with groove steps Y _n ^I = 7, 5 and number of turns 2W _k , W _k for odd groups, Y _n ^I = 6, 4 for even groups moreover, the initial sides of the coils of the first pair of groups are laid in grooves with numbers 1, 2 and 4, 5, and for each subsequent pair of groups, the indicated packing in the grooves is repeated with HAND five grooves with respect to the previous pair of groups, the outer and inner coils each even group formed with numbers of turns, respectively, (1 + x) W _k and (1-x) W _k, and the groups of each phase are connected in series with opposite inclusion even-numbered groups relative odd where p = 1, 2, 3, k = 0, 1, 2, (2p-1); 2W _{k the} number of turns in each groove, and the value of x is chosen in the range of 0.45≅x ≅0.50.

 In FIG. 1 shows a diagram of the proposed winding at p = 3 and Z = 45; in FIG. 2 shows alternating phase zones of the winding of FIG. 1; in FIG. 3 shows the polygon of the MDS winding of FIG. 1; in FIG. 4 and 5 are the same as in FIG. 2 and 3, but for the well-known two-layer winding.

The winding (Fig. 1) is made three-phase with a pole p = 3 in Z = 15p = 45 grooves from K = 6p = 18 coil groups with numbers from 1 ^I to 18 ^I In phases C1, C2, C3, the groups have numbers 1 + 3k for phase C1, 3 + 3k for phase C2, 5 + 3k for phase C3, where k = 0, 1, 2, (2p-1) = 5. The groups contain two concentric coils with groove steps and number of turns equal to U _n = 7, 5 and 2W _k , W _k for odd groups, U _n = 6, 4 and (1 + x) W _k , (1-x ) W _k for even groups, where 2W _{k is the} number of turns in each groove, and the value of x is chosen within 0.45≅x ≅ 0.50 from the condition for obtaining a reduced value of differential scattering. In FIG. 1 phase connected to a star.

In FIG. 2 shows the alternation of the phase zones of the winding of FIG. 1 in the grooves for one repeating part of the winding (Z ^' = 15), where zones A, B, C correspond to the beginnings of the coil groups, and zones X, Y, Z to their ends. In FIG. 3, a polygon of the MDS winding of FIG. 1 for Z ^' = 15 grooves, where the current vectors of the phase zones are shown in the center of the polygon. With pole division, τ = Z / 2p = 45/6 = 7.5, the coil shortening coefficients are sin (π˙7 / 2˙7.5) = 0.9945; sin (π˙5 / 2˙7.5) = 0.8660; sin (π˙6 / 2˙7.5) = 0.9511; sin (4π / 2 ˙ 7.5) = 0.7431.

Then at x = 0.45 the winding coefficient is (0.9945˙2 + 0.8660 + 0.9511 ˙1.45 + 0.7431 ˙0.65) / 5 = 0.9286, and the average pitch of the coils in the grooves At _p.s. = (7 2+ 5+ 6 1.45+ 4 ˙0.65) / 5 = 6.06. In FIG. 3 with the side of the triangular grid equal to unity, the radii of the slot points are determined by the cosine theorem: points 1 and 2 R ₂ ¹ = 4 ² +1 ^{2 2} + 4 = 21; points 3 and 5 R ₃ ² = 3 ² +2 ² + 6 = 19; point 4 R ₄ ² = 4.45 ² = 19.8025 and then the square of the average radius is R _g ² = (21˙2 + 19 ˙2 + 19.8025) / 5 = 19.9605. The square of the radius for the main harmonic MDS is equal to R ² = (ZK _r / p π) ² = (45 ˙ 0.9286 / 3 π) ² = 19.658036 and then the differential scattering coefficient is σ _d = [(R _g / R) ² -1] 100 = 1.538% Similarly, for the well-known two-layer winding (Fig. 4 and 5) with U _p = 6 and K _rev = 0.9099 determine σ _d = 1,726%
Thus, the proposed winding has better electromagnetic parameters compared with the known two-layer winding and the winding of the prototype 0.9286 / 0.9099 = 1.021 times higher Kob and 1.726 / 1.538 = 1.123 times smaller differential scattering at almost the same copper consumption ( the same average pitch of the coils in the grooves). For x = 0.5, they have _Y. To _about = 0.9306 and σ _d = 1.545% with increasing values of x to x = 1 get U _p.av. = 6.2; K _about = 0.9514 and σ _d = 1.768% i.e. the smallest values of the coefficient q correspond to the values x = 0.45-0.50.

 The proposed winding can be used on the stator of electrical AC machines, as well as combined electrical machines with two opposite-pole fields in the magnetic circuit. Its application allows to reduce the amplitudes of higher harmonic MDSs, thereby reducing the inductive scattering resistance of the windings and additional losses in steel from higher harmonic MDSs, as well as to increase the machine efficiency and power factor.

Claims (1)

Three-phase fractional winding of the stator with a pole of p and the number of grooves per pole and phase q 2.5, made in t 15p grooves with numbers from 1 to Z of K 6p coil groups with numbers in phases of the first, second and third, respectively 1 + 3k, 3 + 3k, 5 + 3k, containing in each group concentric coils with pitch steps Y _p 7.5 and the number of turns 2 · W _k and W _k for odd groups,

for even groups, moreover, the initial sides of the coils of the first pair of groups are laid in grooves with numbers 1,2 and 4,5, and for each subsequent pair of groups this laying in grooves is repeated with a shift of five grooves relative to the previous pair of groups, characterized in that and the inner coils of each even group are made with the numbers of turns, respectively (1 + x) W _k and (1 x) W _k , and the groups of each phase are connected in series when the even groups are switched on relatively odd, where p 1,2,3, k 0 , 1,2, (2p 1), 2W _{k the} number of turns in each groove, and the value of x is chosen is within 0.45 ≅ x ≅ 0.50.

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