RU2227357C2 - NINE-PHASE FRACTIONAL (q=4/5) WINDING OF A C ELECTRIC MACHINE - Google Patents

Abstract

FIELD: electrical engineering, electric machine making. SUBSTANCE: invention refers to nine-phase asynchronous motors with squirrel-cage rotors supplied from semiconductor frequency converters in frequency-controlled A C drive. Invention is aimed at achievement of technical result consisting in manufacture of double-layer m=9-phase, m'=18-zone fractional winding with q= 4/5 and p=5 in 2=18pq=72 slots with elimination of most strongly expressed harmonic of fractional order from its magnetomotive force to reduce differential dissipation. Main feature of invention lies in manufacture of double-layer winding with 2p=10 poles with number of slots per pole and phase q= 4/5 and row grouping 1 1 1 1 0 in z=72 slots of K=72 coils with numbers from 1K to 72K and slot pitch y_s.. With number of phases m=9, phase zones m'=2m= 18 coils 1K+4(k) and 4K+4(k) have number of turns (1+1)w_k and coils 2K+4(k) and 3K+4(k) have (1-x)w_c turns. In first phase coils 1K, 16 K,-23K, 30K,-37K, - 52K, 59K,-66K are connected in series with start of phase from start of 1K and its finish from start of 66K and coils of each next phase alternate with interval of 16 numbers within limits of 72 coils with reference to coils of first phase, where y_s = 6,, 2w_c are numbers of turns in each slot, x=10 and value k in numbers of coils changes within limits from 0 to 2m-1=17 and sign (-) by number of coil indicates its connection in opposition in phase. EFFECT: manufacture of windings with reduced differential dissipation. 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 loop symmetrical AC windings made by two-layer 2p-pole of 2pm coil groups with equal-step or concentric coils with a fractional number q = z / 2pm = b + c / d = N / d grooves of 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 = 4/5, performed two-layer in z = 6pq = 24 grooves with a group of coils in a row 1 1 1 1 0 [1] for c / d = 4/5 and b = 0.

The invention aims at performing a two-layer m = 9-phase, m '= 2m = 18-zone fractional winding at q = 4/5 and p = 5 in z = 18pq = 72 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 = 4/5 and grouping in a row 1 1 1 1 0, performed in z = 72 grooves m = 9-phase, m '= 18-zone of K = 72 coils with numbers from 1K to 72K and pitch in grooves at _n : coils 1K + 4 (k) and 4K + 4 (k) have the number of turns in (1 + x) w _k , and coils 2K + 4 (k) and 3K + 4 (k) - along (1-x) w _k turns, in the first phase coils 1K, 16K, -23K, 30K, -37K, -52K, 59K, are connected in series - 66K with the beginning of the phase from the beginning of 1K and its end from the beginning of 66K, and the groups of each subsequent phase alternate with an interval of 16 numbers in p within 72 coils relative to the coils of the first phase, where y _n = 6, 2w _k is the number of turns of each groove, x = 0.10 and the value of k in the numbers of coils varies from 0 to 2m-1 = 17, and the sign (-) when the coil number means its counter inclusion in phase.

Figure 1 shows the recessed grooves of the grooved layers with alternations of m '= 18 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 = 72 grooves, K = 72 coils and q = z / 18р = 4/5 (N = 4 and d = 5) with marking on top of the numbers of coils 1K, 16K, 23K, 30K, 37K, 52K, 59K, 66K of the first phase (zones A and X) and below the groove numbers (from 1 to z = 72); figure 2 - diagrams of the shift of the coils of the first phase for the poles p = 5 (top) harmonic MDS (EMF) ν = 1 and pν = νр = 13 fractional harmonic MDS ν = 13/5 (in the center) at angles α _p = 360 ° / z = 5 ° and γ = α _n / 2d = 0.5 °; figure 3 - the construction of the part of the polygon MDS according to [3] the 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 = 72 grooves, m = 9 phases, m '= 2m = 8 phase zones is made of a two-layer of K = 72 coils with numbers from 1K to 72K and a pitch in grooves at _n = 6 has a fractional number of grooves per pole and phase q = 4/5 at N = 4 and d = 5, i.e. by grouping [1] 1 1 1 1 0 from each N = 4 coils d = 5 groups are formed. For this, a series of 2m = 18 groups 1 1 1 1 0 is compiled, phase zones in the sequence A-A'-A '' - Z-Z'-Z '' - B-B'-B "-X- are marked under it X '' - X "-C-C'-C"-Y-Y'-Y"and cross out the zones under the zero numbers of the row, after which the remaining numbers are marked out successively the number of grooves and the scan of figure 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 angles of shift of the coils of the first of m = 9 symmetrical phases for the poles p = 5 (ν = 1) and pν = νp = 13 (ν = 13/5) in Fig. 1 (from the bottom), the grooves between the coils 1K 16K, 30K, 59K zones A, their symmetry axis O lies midway between the 37K, 52K and relative to the shift angles are equal to p = O → 5 → 14,5α 59K _np = 14.5 · 25 ° = 360 ° + 2.5 ° = ± 0.5α _p and O → 30K = -0.5α _p , O → 1K → 28.5α _p p = 720 ° -7.5 ° = -1.5 · α _p and O → 16K = + 1.5α _p , according to which the upper diagram of Fig. 2 is constructed at an angle α _p = 5 ° (the coils of zones X - 37K, 52K, 66K, 23K are 180 ° offset from the coils of zones A); for rν = 13: 59K → _n → 14,50α pν = 14,5 · 65 ° = 942,5 ° = 13 · 72 ° + 6,5 ⁰ 3 · 72 = ⁰ + 13γ and 30K → O = 2 · 72 ° -13γ, О → 1К → 22.5 · 65 ° = 26 · 72 ° -19.5 ° = 72 ° -39γ and О → 16К = 4 · 72 ° + 39γ, according to which the diagram of Fig. 2 ( in the center) when dividing the circle into p = 5 parts (360 ° / 5 = 72 °) taking into account the oncoming rotation of the harmonic MDS ν = 13/5, where γ = α _n / d20.5 °. _Using the shortening coefficients K _yν = sin (ν90 ° for _p / τ _p ) of the coils (for pole division, τ _p = z / 2p = 7.2), the projections of the EMF of the coils on the vertical axis of symmetry are calculated in FIG. uneven coils:

for pν = 13 (ν = _13/5 ) -K _obν = [(1 + x) cos (72 ° -39γ) - (1-x) cos (36 ° + 13γ)] K _yν / 2 = -0, 01663 + x0.1742 (at K _yν = 0.2588), whence, by the condition K _obν = 0, the value x = 0.10 is determined, at which harmonic ν = 13/5 with pν is eliminated from the EMF of the winding of Fig. 1 = 13;

for p = 5 (ν = 1) -K _ob = [sin (10 °) / sin (2.5 °) + 2xcos (1,5α _p ) -2xcos (0,5α _p )] K _уν / 4 = 0 961335-х0.00367 (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 _revν / νK _rev = 0.0166 / (13/5) 0.9613 = 0.0067 or 0.67% , and for x = 0.10 - 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 = 4 of the groove points of one repeating part of the winding relative to the center, for non-uniform winding at x = 0.10 decreases by ≈50%.

Thus, the proposed winding has the same filling of each groove with a wire of the same cross section, is characterized by reduced differential scattering due to the elimination of fractional harmonic order ν = 13/5 from the MDF, is symmetric m = 9-phase, m '= 2m = 18 -zone, each of its phase shifted by an electrical angle of 40 ° (since the slot 16 corresponds to coils electrical angle phase shift started 16α _n p = 16 · 25 ° = 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 = 4/5) winding of electric AC machines, 2p = 10-pole, two-layer with the number of grooves per pole and phase q = 4/5 and grouping in a row 11110, performed in z = 72 grooves from K = 72 coils with numbers from 1K to 72K and pitch in grooves y _p , characterized in that for the number of phases m = 9 and phase zones m '= 2m = 18, the coils 1K + 4 (k) and 4K + 4 (k) have the number of turns along (1 + x) W _k , and coils 2K + 4 (k) and 3K + 4 (k) - along (1-x) w _k turns, in the first phase, coils 1K, 16K, -23K, 30K are connected in series, -37K, -52K, 59K, -66K with the beginning of the phase from the beginning of 1K and its end from the beginning of 66K, and the coils of each subsequent phase are h alternate with an interval of 16 numbers within 72 coils relative to the coils of the first phase, where y _n = 6, 2w _k is the number of turns of each groove, x = 0.10, and the value of k in the numbers of coils varies from 0 to 2m-1 = 17, and the sign (-) at the number of the coil means its counter-inclusion in phase.

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