RU2231890C2 - Nine-phase fractional-slot winding for alternating-current machines - Google Patents

Abstract

FIELD: electrical and electromechanical engineering; nine-phase squirrel-cage induction motors for variable-speed ac drives.

SUBSTANCE: proposed winding designed for use in variable-speed ac drives supplied with power from semiconductor frequency changers is double-layer winding with pole pair number 2p = 10 and number of slots per pole per phase q = 3/5, whose winding coils are grouped and disposed in row 1 1 0 1 0 in z = 54 slots accommodating 54 coils K numbered from 1K to 54K with slot pitch y_s. With phase number m = 9, belt number m' = 2m = 18 coils 1K + 3(k) and 2K + 3(k), each having (I - x)w_k turns, and each coil 3K + 3(k) has (I + x)w_k turns. Series-connected in first phase are coils 1K, 12K, 23K, -28K, -39K, -50K with starting lead of phase from start of 1K and its finishing lead from start of 50K; coils of each next phase are alternating at interval of 12 numbers within K = 54 coils relative to coils of first phase, where y_s = 6.2w_k is turn number of filled up slot; x = 0.09, and value of k in coil numbers varies between 0 and 2m = 17, minus sign at coil number indicating its differential connection in phase.

EFFECT: eliminating mmf of most pronounced fractional harmonic to reduce differential dissipation in five-phase winding.

1 cl, 3 dwg

Description

The invention relates to the windings of electrical AC machines and can be used, for example, on a stator of asynchronous motors (HELL) with a squirrel-cage rotor, powered by semiconductor frequency converters (IF).

Known are m≥ 3-phase, m '= 2m-zone AC symmetrical loop windings made by two-layer 2p-pole from 2pm coil groups with equal-step or concentric coils with a fractional number q = z / 2pm = b + c / d = N / d grooves z per pole and phase when grouping coils in coil groups, depending on the fractional part c / d of q [1-2]. With the denominator of fractionality d≥ 4, the windings are characterized by a high content of harmonic MDS with a significant deterioration in the performance of electric machines with such windings; with an increase in the number of phases m and phase zones m ’, the harmonic composition of the winding MDS improves.

Closest to the proposed one is a fractional m = 3-phase, m '= 6-zone, 2p = 10-pole winding at q = 3/5, performed by a two-layer in z = 6pq grooves with a group of coils in a row 1 1 0 1 0 from [1] for c / d = 3/5 and b = 0.

In the invention, the task is to perform a two-layer m = 9-phase, m '= 2m = 18-zone fractional winding at q = 3/5 and p = 5 in z = 18pq = 54 grooves while eliminating the most pronounced fractional harmonic for reduction of differential scattering [3].

The solution of this problem is achieved by the fact that for a two-layer fractional 2p = 10-pole winding with the number of grooves per pole and phase q = 3/5 and grouping in a row 1 1 0 1 0, performed in z = 54 grooves m = 9-phase, m '= 18-zone of K = 54 coils with numbers from 1K to 54K and pitch in grooves at _n : coils 1K + 3 (k) and 2K + 3 (k) contain (lx) w _k turns, and coils 3K +3 (k) - along (l + x) W _k turns, in the first phase, 1K, 12K, 23K, -28K, -39K, -50K coils are connected in series with the beginning of the phase from the beginning of 1K and its end from the beginning of 50K, and the coils of each subsequent phase alternate with an interval of 12 numbers within K = 54 coils tnositelno coils of the first phase, wherein y _n = 5, 2w _k - number of turns of the groove completely filled, x = 0.09 and the value for non coils varies from 0 to 2m-1 = 17, and the sign (-) at room coils means its counter inclusion in phase.

Figure 1 shows the recessed grooves of the grooved layers with alternations of m ′ = l8 phase zones A-A'-A ”-Z-Z'-Z” -B-B'-B ”-X-X'-X” - C-C'-C ”-Y-Y'-Y” of the proposed 2p = 10-pole, m = 9-phase, m '= 2m = 18-zone double layer fractional winding with z = 54 grooves, K = 54 coils and q = z / 18p = 3/5 (N = 3, d = 5) with marking on top of the numbers of coils 1K, 12K, 23K, 28K, 39K, 50K of the first phase (zones A and X) and below the numbers of grooves (from 1 to z = 54), where the blackened grooves contain 2 (1-x) \ w _k turns, and all other completely filled grooves contain 2w _k turns; figure 2 - diagram of the shift of the coils of the first phase for the pole p = 5 (top) harmonic MDS (EMF) ν = 1 and the pole pν = ν p = 13 fractional harmonic MDS ν = 13/5 (in the center) at angles α _p = 360 ° / z = 20 ° / 3 and γ = α _n / 2d = 2 ° / 3; figure 3 - the construction of the part of the polygon MDS [3] winding of figure 1 at x = 0, where the center shows the vectors of the symmetric m '= 18-phase system of currents of phase zones A-A'-A ”-Z-Z' -Z ”-B-B'-B” -X-X'-X ”-C-C'-C” -Y-Y'-Y ”.

The winding of FIG. 1 at 2p = 10 poles, z = 54 grooves, m = 9 phases, m ′ = 2m = 18 phase zones is made of a double layer of K = 54 coils with numbers from 1K to 54K and a pitch in the grooves y _p = 5 , has a fractional number of grooves per pole and phase q = 3/5 (N = 3, d = 5), i.e. by grouping [1] 1 1 0 1 0 from each N = 3 coils d = 5 groups are formed. For this, a series of 2m = 18 groups 1 1 0 1 0 is compiled, phase zones in the sequence A-A'-A ”-Z-Z'-Z” -B-B'-B ”-X-X 'are marked below it -X ”-C-C'-C” -Y-Y'-Y ”and the zones are crossed out under the zero numbers of the row, then the numbers of grooves are marked out successively under the remaining numbers and the scan according to FIG. 1 is obtained. The winding at m '= 18-phase zones and d = 5 creates a rotating MDS with harmonic series [2] ν = 18k / d ± 1 = 18k / 5 ± 1 = 1 (+), 13/5 (-), 23 / 5 (+), ..., where ± k is any integer such that ν> 0 (k = 0 for the fundamental harmonic ν = 1), the sign (+) corresponds to harmonic straight lines and (-) inverse.

To determine the shear angles of the coils of the first of m = 9 symmetrical phases for the poles p = 5 (ν = 1) and pν = ν p = 13 (ν = 13/5) in Fig. 1 (from the bottom), grooves between the 1K coils are marked , 12K, 23K zones a, their axis of symmetry lies in the 12K and relative to the shift angles are equal to p = 5-12K → 23K → 11α _n p = 11 · 100 ° / 3 = 360 ° + 20 ° / 3 = + α _p and 12K → 1K = -α _p , according to which the upper diagram of Fig. 2 is constructed at an angle α _p = 20 ° / 3 (the coils of zones X - 27K, 39K, 50K are 180 ° offset from the coils of zones A); for pν = 13-12K → 23K → 11α _p p _p = 11 · 260 ° / 3 = 13 · 72 ° + 52 ° / 3 = 3 · 72 ° + 26γ and 12K → 1K = 2 · 72 ° -26γ, which is built the diagram of figure 2 (in the center) when the circle is divided into p = 5 parts (360 ° / 5 = 72 °) taking into account the oncoming rotation of the harmonic MDS ν = 13/5, where γ = α _n / 2d = 2 ° / 3. _Using the shortening coefficients K _yν = sin (ν90 ° y _n / τ _p ) of the coils (for pole division τ _p = z / 2p = 5.4) and figure 2, the projections of the EMF of the coils on the vertical axis of symmetry are calculated and winding coefficients are determined taking into account uneven coils:

for pν = 13 (ν = _13/5 ) -K _obν = [(1 + х) - (1-х) 2сs (36 ° + 26γ)] К _уν / (3-х) = (- 0,1160+ x1.3104) / (3-x) at K _yν = 0.59716, whence, by the condition К _obν = 0, the value x = 0.09 is determined, at which the harmonic ν = 13 / is eliminated from the EMF of the winding of Fig. 1 5 with pν = 13;

for p = 5 (ν = 1) -K _ob = [sin (10 °) / sin (10 ° / 3) + x-x2cosα _n ] K _y / (3-x) = (2,96628-x0,97981 ) / (3-x) at К _у = 0.96593, i.e. for an equal-turn winding (x = 0), the amplitude of the harmonic MDS ν = 13/5 has a relative value Fν / F = K _оνν / ν K _о = 0.0387 / (13/5) 0.9888 = 0.0151 or 1.51 %, and at x = 0.09 - Fν / F = 0.

The differential scattering of the winding, determined from its MDS polygon of FIG. 3 according to [3], by calculating the squares of radii i = N = 3 of the groove points of one repeating part of the winding relative to the center, decreases for non-uniform winding at x = 0.09 by ≈ 40%.

Thus, the proposed winding is characterized by reduced differential scattering due to the elimination of the fractional harmonic order ν = 13/5 from the MDF (EMF), is symmetric m = 9-phase, m '= 2m = 18-zone, each phase is shifted to electric angle of 40 ° (since an interval of 12 coils corresponds to an electric angle of phase shift of the onset of phases 12α _p p = 12 · 100 ° / 3 = 400 ° -360 ° = 40 °). Its application in a squirrel-cage rotor HELL powered by a 9-phase current inverter allows a three-fold reduction in phase current compared to 3-phase inverters, which significantly reduces the cost of controlled valves and the entire inverter when simplifying its circuit.

Sources of information

1. Livshits-Garik M. Windings of AC machines / trans. from English M.-L.: SEI, 1959, p.224 - prototype.

2. Voldek A.I. Electric cars: Textbook for high schools. L .: Energy, 1978.

3. Popov V.I. Determination of differential scattering of multiphase windings // Electricity, 1987, No. 6, pp. 50-53.

Claims (1)

Nine-phase fractional (q = 3/5) winding of AC electric machines, 2p = 10-pole, two-layer with the number of grooves per pole and phase q = 3/5 and grouping in a row 1 1 0 1 0, performed in z = 54 grooves from K = 54 coils with numbers from 1K to 54K and pitch in grooves y _p , characterized in that for the number of phases m = 9 and phase zones m '= 2m = 18, the coils are 1K + 3 (k) and 2K + 3 (k ) contain (lx) w _K turns, and coils ЗК + 3 (к) - along (l + x) w _K turns, in the first phase, coils 1K, 12K, 23К, -28К, -39К, -50К с the beginning of the phase from the beginning of 1K and its end from the beginning of 50K, and the coils of each subsequent phase alternate with inter scarlet 12 numbers within K = 54 coils relative to the coils of the first phase, where _n = 5; 2w _K is the number of turns of the completely filled groove, x = 0.09, and the value of k in the numbers of the coils varies from 0 to 2m-1 = 17, and the sign (-) with the number of the coil means that it turns on in phase.

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