RU2293425C2 - ASYMMETRIC THREE-PHASE FRACTIONAL-SLOT WINDING WITH 2p = 6c POLES IN z = 60c SLOTS - Google Patents

Abstract

FIELD: electrical and electromechanical engineering; three-phase induction and synchronous machines including slip-ring induction motors.

SUBSTANCE: proposed asymmetric three-phase double-layer m' = 3-band winding with 2p = 6c poles placed in z = 60c slots with slot number per pole per phase q = z/3p = 20/3 has 3pc coil groups with coil grouping 7 6 7 6 7 7 7 7 6 repeated c times. Novelty is that concentric coils have slot pitch y_si = 16-2(i - 1) and turn number (1 - x)w_c for coils with i' = 1, 7 and turn number (1 + x)w_c for coil with i = 4 in seven-coil groups, slot pitch y'_si = 15 - 2(i - 1) and turn number (1 + x)w_c for coil with i' = 4 in six-coil groups; turn number for remaining coils of coil groups equals w_c, where c = 1, 2, 3, ...; i' = 1 - 7 and i' = 1 - 6 are coil numbers in coil groups starting from external one; 2w_c is turn number in slots completely filled with winding; x = 0.5.

EFFECT: reduced asymmetry and differential scatter ratios.

1 cl, 4 dwg

Description

The invention relates to three-phase windings of electrical machines of alternating current - asynchronous and synchronous.

Known two-layer loop m = 3-phase fractional windings are known, performed at 2p poles in z grooves from m′p coil groups with equal-step or concentric coils with an average pitch of grooves y _to ≈z / 2p, the number of grooves per pole and phase q = z / m′p = b + c / d, where m ′ = 2m = 6 or m ′ = m = 3 is the number of phase zones or a couple of poles, c / d <1; according to symmetry conditions, the 2p / d ratios are integer, d / m are non-integer [Voldek A.I. Electric cars. L .: Energy, 1978, S. 392-394].

Grouping coils in groups of fractional asymmetric (d / m - integer) windings are given in rows and depend on c / d [Livshits-Garik M. Windings of AC machines / Per. from English L .: GEI, 1959, p. 254], for example 767677776 for q = 20/3: differential scattering increases due to phase asymmetry.

The invention is famous for the task of reducing the asymmetry coefficients, differential scattering of an asymmetric m ′ = 3-zone winding at q = 20/3.

The solution of this problem is achieved by the fact that for m = 3-phase asymmetrical test winding at 2p = 6 · with poles in z = 60 · with grooves, a two-layer m ′ = 3-zone with the number of grooves per pole and phase q = z / 3р = 20/3 of 3р · from coil groups with a grouping 767677776, repeated with time:

concentric coils have _groove steps y _Pi = 16-2 (i-1) with the number of turns (1-x) w _{to the} coils with i = 1.7 and (1 + x) w _{to the} coils with i = 4 for groups of seven-coil , y ′ _Пi = 15-2 (i′-1) with the number of turns (1 + x) w _{to the} coils with i ′ = 4 for six-coil groups with w _{to the} turns of the remaining coils of the groups, where c = 1, 2, 3, ..., i = 1 ... 7 and i = 1 ... 6 are the numbers of coils in the groups, starting with the outer one, x = 0.5, and 2w _k is the number of turns of the grooves completely filled with the winding.

Figure 1 shows a scan of the groove layers of the proposed winding with c = 1, 2p = 6, z = 60 with numbers 1 ... 60 from below, 3p = 9 groups with numbers 1G ... 9G from above, alternating phase zones A-B - From the upper, XYZ lower layers, where the blackened grooves contain (2) w _to turns at 2w _to turns in the remaining grooves, and the shifts of the axes of the groups are marked from below; Figure 2 is constructed diagram shifts EMF groups phases E _A, E _B. E _C relative to the axis of symmetry of the 2G group; figure 3, 4 are built on a triangular grid are built polygons of the MDS winding of figure 1 for coils equal- (figure 3) and non-equal-coil (figure 4). The m'-zone winding of Fig. 1 is connected by series-consonant inclusion in the phases of the groups: 1G, 4G, 7G in phase I, 2G, 5G, 8G in phase II, 3G, 6G, 9G in phase III with beginnings of 1G, 2G 3G; phases can be conjugated by a star or a triangle. With c = 2, 3, ... the winding has 2p = 6s = 12, 18, ... poles, z = 60s = 120, 180, ... grooves and 3pc = 18, 27, ... groups.

For the winding of FIG. 1, EMF groups are determined by the shortening coefficients of concentric coils K _yi = sin (90yi / τ _П ) = sin (9 ° у _i ) at pole division τ _П = z / 2р = 10: Е _тб = 5, 69572-x0.17557 for groups of seven-coil (large), E _tm = 5.17160 + x0.98769 for six-coil (small).

, D=

и K_нес%=(F/D)100 [Петров Г.Н. Электрические машины, ч.2. Асинхронные и синхронные машины. М.-Л.: ГЭИ, 1963, C.162] вычисляется коэффициент несимметрии К_нес%=0,84 % при К_об=(Е_АС+2Е_ВА)/

·60=0,82432 (x=0).The diagram of FIG. 2 is constructed for 2p = 6, z = 60, α _P = 360 ° / z = 6 ° and the angles of the shift of the axes of the groups of FIG. 1: 2G → 3G = 6.5α _P p = 117 ° = 120 ° + 0.5α _P ; 2G → 1G = 240 ° + 0.5α _P and 2G-4G = 13 (18 °) = 234 ° = 240 ° + α _P and 2G → 9G = 120 ° + α _P ; 2G → 5G = 19.5 (18 °) = 351 ° = 360 ° -1.5α _P and 2G → 8G = 360 ° + 1.5α _P ; 2G → 6G = 26.5 (18 °) = 120 ° -0.5α _P and 2G → 7G = 240 ° + 0.5α _P , according to which the phase emf is equal to E _B = E _{2G (m)} + 2E _{5G (b )} cos (9 °) = 16.4228 + x0.64087 - vertical vector, Е ² _А = (2Е 1Г _(b) ) ² + Е ² _{4Г (m)} -4Е 1Г _(b) Е _{4Г (m)} cos ( 180 ° -9 °) - by the cosine theorem and at x = 0-E _A -E _C = 16.5182, and the angle γ in Fig. 2 is determined by the sine theorem E _tm / sinγ = E _A / sin (171 °), whence γ = 2.8073 °, then the phase angle EMF shifts are φ _BA = φ _BC = 120 ° -3 ° + γ = 119.8073 and φ _AC = 120.3854 °. From the phase EMF and shear angles, the linear EMF a = E _BA = b = E _BC = 28.50, c = E _AC = 28.6658 are determined, then by the expressions: S-a + b + c, A = (a ² + b ² + s ² ) / 6, B =

, D =

and K _carried% = (F / D) 100 [Petrov G.N. Electric cars, part 2. Asynchronous and synchronous machines. M.-L.: SEI, 1963, C.162] the coefficient of asymmetry is calculated K _carried% = 0.84% at K _about = (E _AC + 2E _VA ) /

60 = 0.82432 (x = 0).

(z=3x)=0,86176 и z'=60-3x=58,5 - эквивалентное число полностью заполненных обмоткой пазов, т.е. она имеет больший К_об и меньший К_нес% (в 0,84/0,16=5,25 раза).Similarly, for the unequal winding of FIG. 1, at x = 0.5: E _B = 16.7432, E _A = E _C = 16.8349, γ = 3.0177 °, φ _VA = φ _BC = 120.0177 ° , φ _AC = 119.9646 °, a = E _BA = b = E _BC = 29.0822, c = E _AC = 29.1537, K _carried% = 0.16, K _rev = (E _AC + 2E _VA )

(z = 3x) = 0.86176 and z '= 60-3x = 58.5 is the equivalent number of grooves completely filled by the winding, i.e. it has a larger K _about and a smaller K _carried% (0.84 / 0.16 = 5.25 times).

From the MDS polygons of Figs. 3, 4 (with unit current vectors of phase zones A-Z-B-X-C-Y in the center) according to a triangular grid and the relations

the differential scattering coefficient σ _D% is determined, which characterizes the quality of the winding but the harmonic composition of the MDS with the square of the average radius j = 1 ... z of the groove points R ² _d , the radius R _{o of the} circle for the main harmonic Determination and optimization of the parameters of three-phase windings along MDS polygons // Electricity. 1997, No. 9, p. 53-55]:

According to (1) - (2): at x = 0, K _rev = 0.82432-R ² _d = 1707/60, R _o = 60 · 0.82432 / 3π, σ _D% = 3.31; at x = 0.5 and K _about = 0.86176-R ² _d = 1746.5 / 60, R _o = 58.5 · 0.86176 / 3π (for z '= 60-3x = 58.5), σ _D% = 1.74%, i.e. σ _D% decreases 3.31 / 1.74 = 1.90 times; the average step of the coils in _Psr = Σ (in _Pi w _Ki ) / z '= (600-33x) / (60 / 3x) = 9.974. Given the changes in K _about , K _carried% , σ _{d%, the} winding of Fig. 1 with x = 0.5 has a high efficiency K _eff = (0.86176 / 0.82432) (0.84 / 0.16) (3 31 / 1.74) (58.5 / 60) = 10.2.

The proposed m = 3-zone winding in comparison with m = 6-zone at z = 60, 2p = 6, q = z / 6p = 10/3, for _P = 4, the grouping 433334343 has reduced K _nes and σ _D with half as many groups.

Its application allows to reduce additional losses in the rotor and magnetic noise in asynchronous squirrel-cage motors, to improve the shape of the voltage curve in synchronous generators.

Claims (1)

Three-phase asymmetric fractional winding at 2p = 6s poles in z = 60s grooves, performed by a two-layer m ′ = 3-zone with the number of grooves per pole and phase q = z / 3p = 20/3 of 3pc coils with a grouping of 7 6 7 6 7 7 7 7 6, repeated with times, characterized in that the concentric coils have _groove steps y _pi = 16-2 (i-1) and the number of turns (1-x) w _k for coils with i ′ = 1.7 and the number turns (1 + x) w _k for a coil with i = 4 for seven-coil groups, groove steps y ′ _pi = 15-2 (i-1) and the number of turns (1 + x) w _k for a coil with i ′ = 4 for groups of six-coil groups, while the number of turns of the remaining coils of the coil groups is w _k , where c = 1, 2, 3, ...; i ′ = 1 ... 7 and i ′ = 1 ... 6 are the numbers of coils in the coil groups, starting from the outer; 2w _to - the number of turns in the grooves, completely filled with a winding; x = 0.5.

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