RU2267203C2 - THREE-PHASE TWO-LAYER SPLIT (q=2,5) WINDING OF ELECTRIC MACHINES - Google Patents

Abstract

FIELD: electric radio engineering and electric mechanical engineering, possible use in three-phase asynchronous and synchronous electric machines.

SUBSTANCE: three-phase two-layer split (q=2,5) winding is made 2p=4c-polar in z=6cq grooves of 6c coil groups: three-coil non-even and two-coil even ones with average step of concentric coils y_c≈z/2pc. In acc to invention, three-coil groups have coil steps y_gi=6,4,2 with coil numbers (1-x)w_c, (1+x)w_c, (1-x)w_c, and two-coil groups have steps y_gi'=5,3 with coil numbers w_c,(1+x)w_c, where c=1,2,3,..., - integer number, z=15c, y_c=1,5q+0,25=4 and 2w_c - number of coils of each groove for value x=0,54.

EFFECT: better composition of harmonic operation ampere-turns and decreased differential dissipation σ_d of symmetric m'=3-zone split (q=2,5) winding.

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Description

The invention relates to three-phase windings of electrical AC machines, can be used on a stator of three-phase asynchronous and synchronous machines, a phase rotor of asynchronous motors.

Loop two-layer symmetrical m = 3-phase windings are known, performed by 2-pole in z grooves from m'p coil groups with the number of grooves per pole and the phase q = z / m'p whole or fractional, where m'- the number of phase zones per a pair of poles equal to m '= m = 3 (three-zone windings) or m' = 2m = 6 (six-zone windings) [Voldek A.I. Electric cars. L .: Energy, 1978, S. 392-393]. With a fractional number qN / d-b + 0.5 (d = 2, b = 1, 2, 3, ...) they have unequal alternating coil groups: large (b + 1) -coil and small b-coil with equal-step or concentric coils with an average groove pitch of _n ≈ z / 2p, and the harmonic composition of their MDS in the series ν = m'k / d ± 1 [ibid., p. 450] is especially unfavorable for m '= 3-zones (ν = 3k / 2 ± 1) due to the presence of a subharmonic ν = 1/2 with a significant increase in differential scattering σ _d and therefore m '= 3-zone fractional (q = b + 0.5) windings are practically not used.

The invention seeks to improve the composition of the MDF of a symmetric m '= 3-zone fractional (q = 2.5) winding by eliminating the subharmonic ν = 1/2 and reducing the differential scattering σ _d .

The solution of this problem is achieved by the fact that for a three-phase 2-layer fractional (q = 2.5) winding, performed 2p = 4c-pole in z = 6cq grooves from 6s coil groups of three-coil odd and two-coil even with an average step concentric coils at _k ≈ z / 2pc: the three-coil groups have coil steps at _pi = 6, 4, 2 with the number of turns (1-x) w _k , (1 + x) w _k , (1-x) w _k , and double-coil - y ' _pi = 5, 3 with the numbers of turns w _k , (1 + x) w _k , where c = 1, 2, 3, ... an integer, z = 15 s, y _k = 1,5q-i 0,25 = 4 and 2w _k is the number of turns of each groove at x = 0.54.

Figure 1 shows the reamers of the groove layers of the proposed winding at 2p = 4 (c = 1), q = 2.5, z = 15 grooves with numbers 1 ... 15, 6s = 6 coil groups with numbers 1G ... 6G (groups 1G, 4G of the first phase are marked), by alternating phase zones in the sequence A-B-C of the upper and X, Y, Z of the lower layers; figure 2, 3 built (on a triangular grid) polygons MDS with coils is equal to - (figure 2), unequal (figure 3) for x = 0.5. With c = 2, 3, ... the winding has 2p = 4c = 8, 12, ... and the sweep of Fig. 1 is repeated 2, 3, times.

The proposed m '= 3-zone winding is connected in phases in the usual way with sequentially-consistent inclusion of phase groups: 1G, 4G with the beginning of the phase from the beginning of 1G in phase I; 3G, 6G with the beginning of 3G in phase II; 5G, 2G with a start of 5G in phase III, and the phases can mate in Y or in Δ.

The winding in Fig. 1 with q = 2.5 for groups of three-coil has coil steps in grooves at _pi = 6, 4, 2 (at _k = 1.5q + 0.25 = 4) with the number of turns (1-x) w _k , (1 + x) w _k , (1-x) w _k , for double-coil - y ' _pi = 5, 3 with the number of turns w _k , (1 + x) w _k , w _k and the value of x is determined from the condition minimizing the differential scattering coefficient σ _d . Coil shortening coefficients K _уi = sin (90 ° у _pi / τ _p ) are determined by pole division τ _p = z / 2p = 15/4 = 3.75, 2w _к = 2 turns of the groove: K _уi = (1-x) 0.587785 (for _pi = 6), (1 + x) 0.99452 (for _pi = 4), (1-x) 0.74315 (for _pi = 2); 0.866025 (y ' _pi = 5), (1 + x) 0.9510565 (y' _pi = 3), then K _about and at _p.s. are equal:

Of the polygons MDS figure 2 and 3 in terms of

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and

the differential scattering coefficient σ _d is determined, which characterizes the quality of the winding by the harmonic composition of its MDS, where R ² _d is the square of the average radius j = 1 ... 2q of the slot points relative to the center of the polygon and R _o is the radius of the circle for the main harmonic MDS [Popov V. AND. Determination and optimization of the parameters of three-phase windings along MDS polygons // Electricity, 1997, No. 9, p. 53-55].

According to (1) - (2) from the MDS polygons of Figs. 2, 3, with the grid side per unit length (in the center of the polygons, the unit current vectors of phase zones A-Z-B-X-C-Y are shown) by the cosine theorem we determine:

at x = 0 (Fig. 2): R ² _j = 1 ² - for the point j = 1, R ² _j = 2 ² = 4 - for the points j = 2, 5, R ² _j = 2 ² + 1 + 2 = 7 - for points j = 3, 4 and R ² _d = Σ (R ² _j ) / 5 = 23/5 = 4, 6, R _o = 15 · 0.82851 / 2π, σ _d% = 17.58 ; at x = 0.5 (Fig. 3): R ² _j = 2 ² = 4 = (1 + 2x) ² = 1 + 4x + 4x ² - for j = 1, R ² _j = 2 ² +0.5 ² + 1 = 5.25 = 2 ² + x ² + 2x = 4 + 2x + x ² - for j = 2, 5, R ² _j = 1.5 ² 4 + 1 + 1.5 = 4.75 = (2-x) ² + 1 + 2-x = 7-5x + x ² - for j = 3, 4 and

and according to (1) - (3) from the condition d (σ _d ) / d (x) = 0, the optimal value x _opt = 0.54 is calculated, which corresponds to the minimum value of σ _{d% min} : for x _opt = 0.54 by ( 1) and (3) - To _about = 0.89489, R ² _d = 24.2528 / 5, R _o = 15 · 0.89489 / 2π and the value of σ _{d% min} = 6.28 is significantly reduced in (17, 58 / 6.28 = 2.80 times) due to the elimination of the subharmonic ν = 1/2; taking into account the increase in the winding coefficient, its efficiency is equal to K _eff = (0.89489 / 0.82851) (17.58 / 6.28) = 3.02 with y _pp = 3.89.

The winding with m '= 3, 2p = 4, z = 15, q = 5/2 and d = 2 (Fig. 1) corresponds to the m' = 6-zone winding with half the number q = 5/4 and d = 4 , which for y _n = 3 and equal-coil coils has K _rev = 0.9098, R ² _d = 5.2 and σ _d% = 10.22, i.e. the proposed m '= 3-zone winding in Fig. 1 with x _opt = 0.54 exceeds m' = 6-zone by differential scattering by 10.22 / 6.28 = 1.63 times.

Thus, the proposed symmetrical m '= 3-zone fractional (q = 2.5) winding is characterized by a significant (2.8 times) decrease in σ _d% and an increase in K _rev , which increases its efficiency in K _eff = 3.0 times in comparison with an equal-turn winding; it is simpler m '= 6-zone winding in manufacture due to half the number (3p) of coil groups.

Claims (1)

A three-phase fractional-layer (q = 2,5) winding of electrical machines performed 2p = 4 c - a pole z = 6cq grooves 6c of the coil groups, three-coil odd and even dvuhkatushechnyh middle step in concentric coils _to ≈z / 2pc, wherein that the three-coil groups have steps of coils at _pi = 6.4.2 with the number of turns (1-x) w _k , (1 + x) w _k , (1-x) w _k , and double-coil at _pi '= 5.3 with the numbers of turns w _k , (1 + x) w _k , where c = 1, 2, 3, ... is an integer, z = 15c, y _k = 1,5q + 0,25 = 4 and 2w _k - the number of turns of each groove with x = 0.54.

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