RU2091961C1 - Three-phase fractional-slot (q=12/5) electrical machine winding - Google Patents

Abstract

FIELD: multipolar AC machines. SUBSTANCE: double-layer winding with number of poles 2p=10 in 72 slots of 30 groups numbered from 1G to 30G with coils grouped in row 32322 repeated 6 times, the coils of three-coil groups 1G+(5c)G and 3G+(5c)G have numbers of turns (1-x)W_coil,(1+x)W_coil,(1-x)W_coil respectively, and the coils of the two - coil groups have W_coil turns each for groups 2G+(5c)G, (1+X)W_coil, and W_coil turns for groups 4G+(5c)G, W_coil and (1+X)W_coil turns for groups 5G+(5c)G, spacing in slots y_s=6, K=0,1,2... (2p-1), c=0,1,2,...(P), 2W_coil - number of turns in a slot, and 0.25=x=0.35. EFFECT: reduced differential dissipation. 4 dwg

Description

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

Known are m = 3-phase windings performed by two-layer, 2m = 6-zone windings with the number q = z / 2pm = z / 6 grooves (z) per pole (2p) and phase (m) whole or fractional [1, 2] Three-phase windings with a fractional number q (fractional windings), represented as
q = z / 6p = b + c / d = N / d,
can be fulfilled with q> 1 (for b и 0 and N> d), in order to obtain a symmetrical winding, the following conditions must be met: 2p / d is an integer, and d / 3 is not an integer, where b, c, d, N integers and c / d are regular irreducible fractions.

 The disadvantage of fractional windings is the high content of harmonics in the MDS curve, which increases their differential scattering and worsens the performance of electric machines with such windings.

Closest to the proposed one is a three-phase fractional winding with q = 6/5 at 2p = 10 poles and z = 36 grooves, performed by a two-layer with unequal coils and characterized by a low content of harmonic in the MDS curve [4]
In the present invention, the task is to reduce the differential scattering of a three-phase fractional winding with q = 12/5.

The problem is solved in that for a three-phase fractional (q = 12/5) winding of electric machines, made of a two-layer with a pole of 2p = 10 in z = 72 grooves from uniformly displaced coils with a pitch in grooves y _p combined in 6p = 30 coil groups with numbers from 1G to 30G when grouping coils in them in a series of 3 2 3 2 2, repeated six times, containing in the first phase series-connected groups with numbers 1G + (3k) G when they turn on even groups with respect to odd ones, and for the other two phases, their numbers alternate at intervals of 2p = 10 and 4p = 20 groups: the first, second, third in the three-coil groups 1G + (5s) G and 3G + (5s) G have the number of turns, respectively (1-x) • W _to , (1 + x) • W _to , (1-x) • W _k , and the coils first and second of the remaining two-coil groups have the number of turns in W _k for groups 2Г + (5с) Г, (1 + х) • W _к and W _к for groups 4Г + (5с) Г, W _к and ( 1 + x) • W _k for groups 5Г + (5с) Г, where y _п = 6; k = 0, 1, 2, (2p-1); c = 0, 1, 2, (p); 2W _{to the} number of turns of each groove, and the value of the parameter "x" is selected within 0.25 ≅ x ≅ 0.35.

 In FIG. 1 shows a scan of the groove layers of the proposed winding with unequal coils at q = 12/5, 2p = 10 poles and z = 72 grooves with the marking of the groove numbers (bottom), coil groups (top) and phase zones; in FIG. 2 and 3, stars of the groove EMF of the upper layer of the first phase are constructed for the polarities p = 5 (Fig. 2) and p '= 1 (Fig. 3); in FIG. 4 polygons of the MDS winding of FIG. 1 with coils of equal-turn (internal) and non-equal-coil (external).

The proposed three-phase two-layer winding for 2p = 10 and z = 72 has a fractional number of grooves per pole and phase q = N / d = 12/5 for pole division τ _p 3q = 36/5 and is made of uniformly displaced coils with a pitch in grooves y _n = 6, combined in 6p = 30 reel groups with numbers from 1G to 30G. In accordance with expression (1), d = 5 coil groups are formed from N = 12 neighboring coils; therefore, winding coils with q = 12/5 and 2p = 10 are grouped [1] in a row 3 2 3 2 2 repeated 6 times. This is shown in FIG. 1 scan of the grooved layers, where the phase zones of the phases of the first, second, third are indicated as AX, B-Y, CZ, alternate in the sequence AZBXCY and the groups of zones X, Y, Z should be included in the phases opposite to the groups of zones respectively A, B , FROM.

It is known [2] that m = 3-phase, 2m = 6-zone fractional windings contain harmonic orders in the MDS curve
ν = 6 • k / d ± 1, (2)
where k is any positive or negative number (including k = 0) for which ν>0; d is the denominator of the fractionality of q by (1), and the signs (+) and (-) refer respectively to directly and counter-rotating harmonics.

For the proposed winding with d = 5, in accordance with (2), we have n = 6 • k / 5 ± 1, whence we get: for k = 0-n = 1 the main harmonic with the number of poles is 2p = 10; for k = 1-n6 / 5-1 = 1/5, the lowest fractional harmonic (inverse) with the number of poles is 2p _ν = ν • 2p = 2 (we do not consider the remaining harmonic here). Such a lower (n = 1/5) harmonic has the greatest effect on the winding MDS and increases its differential scattering, therefore, we determine the conditions for its elimination.

для гармонической ν=1/5 с полюсностью р=1 (фиг. 3)

где K_y= sin p•6/6q) для n=1 и K_yν=sin p•6/5•6q) для n=1/5, при этом все пазы содержат одинаковое число (2•W_k) витков.The pitch angle of the winding grooves of FIG. 1 is equal to: for the main harmonic (ν = 1) -α = (360 ^° / z) • p = α ′ • p = 25 ^° , where α ′ = 360 ^o / z = 5 ^o ; for the lower harmonic (ν = 1/5) -α _ν = (ν • p) α = 5 ^q = α ′. The stars of the groove EMF of one (upper) layer of the phase of the winding of FIG. 1 with unequal coils are constructed for n = 1 (p = 5) in FIG. 2 and for n = 1/5 (p '= 1) in FIG. 3, where the circle is divided into z = 72 parts and phase zones A and X of the first phase are marked. By calculating the projections of the groove EMF vectors onto their axis of symmetry in FIG. 2 and 3, distribution coefficients K _p are calculated, after multiplying by shortening coefficients K _y , winding coefficients K _rev are determined:
for harmonic n = 1 with a pole of p = 5 (Fig. 2)

for harmonic ν = 1/5 with a pole of p = 1 (Fig. 3)

where K _y = sin p • 6 / 6q) for n = 1 and K _yν = sin p • 6/5 • 6q) for n = 1/5, while all the grooves contain the same number (2 • W _k ) of turns.

It can be seen from (3) - (4) that for the known winding with equal-coil coils (x = 0) we have for n = 1-K _about 0.9227, for n = 1/5-K _obv 0.01131 and MDF F _ν of this harmonic from MDS F _{1 the} main harmonic is F _ν / F ₁ = K _{rev ν} / K _rev • ν 5 • 0.01131 / 0.9227 = 0.061, i.e. such a harmonic is strongly expressed in the MDS winding. For its complete elimination from the condition K _obν = 0 by (4) we obtain x = 0.24.

где R $\genfrac{}{}{0ex}{}{\text{2}}{\text{д}}$ - квадрат среднего радиуса q•d пазовых точек одной повторяющейся части многоугольника МДС; R радиус окружности для основной гармонической МДС с обмоточным коэффициентом K_об.The percentage of all (lower and higher) harmonics in the MDS winding curve is estimated using the differential scattering coefficient d _d% , determined by the expressions [3]

where r $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ - the square of the average radius q • d of the groove points of one repeating part of the MDS polygon; R is the radius of the circle for the main harmonic MDS with a winding coefficient K _rev .

In FIG. 4, using the auxiliary triangular grid, the polygons of the MDS winding of FIG. 1, where the number of turns w corresponds to 1 side of the grid with coils of equal turns (x = 0; inner in Fig. 4) and 1.5 sides of the grid with coils of unequal (x = 1/3; outer in Fig. 4). Using the MDS polygons (using the cosine theorem) and expressions (5), we determine:
at x = 0 R $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ = 55/3, R = (72 • 0.9227 / 5π and d _d% 2,493;
at x = 1/3 R $\genfrac{}{}{0ex}{}{\text{2}}{\text{d}}$ = 502.25 / (12 • 2.25), R = (72 • 0.9323 / 5π and d _{d% /} = 1.86, i.e. the differential scattering decreases at x = 1/3 in 2.493 / 1 , 86 = 1.34 times, which shows the effectiveness of the proposed winding; with a value of x = 0.25 according to (4) we have K _rev = 0.9299 and then δ _d% = 1.856; the values of the parameter “x” are chosen within 0, 25 ≅x≅0.35.

 Thus, the proposed fractional winding has a reduced differential scattering (more than 1.3 times) compared with the known one and its application significantly improves the energy and vibro-acoustic characteristics of electric machines due to the improvement of the harmonic composition of the field.

The proposed winding can also be used in electric combined AC machines with two opposite-pole magnetic fields in the magnetic circuit, for example, in three-phase asynchronous single-machine frequency converters 50/300 Hz with the number of pole pairs of the fields of the motor and generator parts p ₁ = 1 and p ₂ = 5, however, such a winding will not be mutually inductively connected to the field 2p ₁ = 2-pole motor winding.

Claims (1)

Three-phase fractional (q 12/5) winding of electrical machines, made of two-layer with a pole of 2p 10 in z 72 grooves from uniformly displaced coils with a pitch in the groove y _p , combined in 6p 30 coil groups with numbers from 1G to 30G when grouping coils in them in a row 3 2 3 2 2 repeated six times, containing in the first phase series-connected groups with numbers 1Г + (3к) Г when the even groups are turned on relatively odd, and for the other two phases, their numbers alternate at intervals of 2p 10 and 4p 20 groups, characterized in that the coils are first, second, tr The families in the three-coil groups 1Г + (5с) Г and 3G + (5с) Г have the number of turns, respectively (1 x) W _к , (1 + x) W _к , (1 x) W _к , and the first and second coils of the remaining two-coil groups have numbers of turns in W _to for groups 2Г + (5с) Г, (1 + x) W _to and W _to for groups 4Г + (5с) Г, W _to and (1 + x) W _to for groups 5Г + ( 5c) D, where y _n 6, k 0, 1, (2p 1), with 0, 1, 2, p, 2W _{k the} number of turns of each groove, and the value of the parameter x is selected within 0.25 ≥ x ≥ 0, 35.

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