CN1008419B - Reduce the electric rotating machine of cogging torque - Google Patents
Reduce the electric rotating machine of cogging torqueInfo
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- CN1008419B CN1008419B CN 85105975 CN85105975A CN1008419B CN 1008419 B CN1008419 B CN 1008419B CN 85105975 CN85105975 CN 85105975 CN 85105975 A CN85105975 A CN 85105975A CN 1008419 B CN1008419 B CN 1008419B
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Abstract
Electric rotating machine has columnar permanent magnet assembly and by the armature core of magnetic materials assembly, the many N utmost point and S utmost points along the motor shaft arranged alternate is arranged, and electrode number is even number P.Armature core has many teeth that place between two adjacent slot for winding, and the number of teeth is the integer T that is not less than 2P.Polyphase windings group coil is embedded in the slot for winding of armature core, and polyphase windings group number of phases is to be not less than 2 integer.Armature core has a pair of short element and long unit at least, each length or short element are one group of teeth, this group tooth has two teeth of arranging successively at least, short element has a short tooth and a full-height tooth at least, not long tooth, at least one long tooth of long unit and a full-height tooth, not short tooth, effective joint square of full-height tooth equals D=(360/T) degree, and short tooth is littler than D, and long tooth is bigger than D.
Description
The present invention relates to a kind of electric rotating machine, particularly a kind of electric rotating machine that comprises the armature core that magnetic material is made, it has the overlapping winding coil and the excitation permanent magnet assembly of many teeth, many polyphase windings.Excitation permanent magnet assembly polarize out the many alternating N and the S utmost point, these N, the S utmost point is relative with the described tooth of armature core.The number of poles of the N and the S utmost point is P, and it is an even number, and the number of teeth is T, and it can be less than 2P.
Electric rotating machine comprises armature core of magnetic materials, and it has many teeth and excitation permanent magnet assembly, and this assembly has the magnetic pole relative with tooth, and such motor is owing to its high efficiency is widely used.But in the prior art, because the strong cogging torque that between the tooth of the magnetic pole of permanent magnet and armature core, interacts and produce, thereby there is the problem that produces nuisance vibration.This cogging torque has hindered the steady rotation of electric rotating machine.In order to reduce this cogging torque, adopt oblique armature core in some cases.But it is difficult making oblique armature core, and can not subdue cogging torque fully.Use in order to be rotated stably that not have the armature core of tooth be unpractical, because its efficient is low and require the size of motor big.
The electric rotating machine structure that reduces cogging torque is at United States Patent (USP) 4,280,072 or the specification of day disclosure (not have to examine) patent application 55-71163 in open.In these patent specifications, indent partly is used for reducing cogging torque.The effect of this method is significantly, at number of teeth T less than 2 times the N and the quantity P of the S utmost point
1(be under the situation of T＜2P), as United States Patent (USP) 4,280, Fig. 1, the Fig. 5 in 072, electric rotating machine shown in Figure 6 are because the surface of each tooth is enough wide, so that the part of many indents is provided in the above.But, at United States Patent (USP) 4, to be not less than the cogging torque of the electric rotating machine of 2P be (same electric rotating machine is open in Japanese publication 55-71163) that impossible effectively be eliminated by described method for as shown in Figure 8 T in 280,072.
Common electric rotating machine will be described in detail below.
Fig. 1 is the diagrammatic cross-sectional view of the common electric rotating machine of T=6P.In Fig. 1, a cylindrical shape permanent magnet 3 is fixed on the exterior periphery of the rotor of being made by magnetic material 2, and permanent magnet 3 rotates around rotating shaft 1 with rotor 2.Permanent magnet 3 has four alternating N and the S utmost point, and all is separated by between them 90 °, that is, P=4, the tooth 6 of armature core 4 be in the face of the magnetic pole of permanent magnet 3, and each tooth forms between two adjacent slot for windings 5.The rotating shaft 1 of rotor 2 rotatably is supported on the armature core 4.Therefore, the relative position between the magnetic pole of the tooth 6 of armature core 4 and permanent magnet 3 changes according to the rotation of rotor 2.
Fig. 2 has represented the expanded view to common electric machine among Fig. 1, and it launches along X-X ' and Y-Y ' line, and at this moment these lines become delegation.Armature core 4 has 24 slot for windings, and from a to X, they are separated by with 15 ° of angles that are equal to and 24 teeth are arranged between the two adjacent slot for windings, that is, and and T=24, overlapping winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 are wound onto in the slot for winding from a to X.Each winding coil in from A1 to C4 is around five teeth of armature core 4.That is to say that A1 is in slot for winding a and f, A2 is in slot for winding g and l, A3 is in slot for winding m and r, and A4 is in slot for winding S and X, and B1 is in slot for winding e and j, B2 is in slot for winding K and P, and B3 is in slot for winding q and v, and B4 is in slot for winding W and d, C1 is in slot for winding i and n, and C2 is in slot for winding O and t, and C3 is in slot for winding u and b, C4 in slot for winding C and h, winding coil A1, A2, A3 and A4 are connected in series, thereby form the winding group A of first phase.Winding coil B1, B2, B3 and B4 are connected in series, thereby form the second phase winding group B.Winding coil C1, C2, C3 and C4 are connected in series, thereby form third phase winding group C.Phase difference between winding group A, B and the C equals the 120el(electrical degree) here 180el equal 1 pole span of the 360/P of permanent magnet 3.In Fig. 1, P=4,180el equals 90 ° (mechanical angles) so.Therefore, provide three-phase current just can obtain the moment of torsion of accelerating rotor 2 to three phase winding group A, B and C.
Fig. 3 represents the diagrammatic cross-sectional view of the another kind of common electric rotating machine of T=3P, except that the relation and winding spacing of T and P, the structure of common electric machine shown in Figure 3 is identical with the structure of common electric machine shown in Figure 1, cylindrical permanent magnet 13 is fixed on the exterior periphery of the rotor of being made by magnetic material 12, and permanent magnet 13 and rotor 12 rotate together around rotating shaft 11.Permanent magnet 13 has four alternating N and the S utmost point, and they separate with 90 ° of angles mutually, that is, P=4, the tooth 16 of armature core 14 be in the face of the magnetic pole of permanent magnet 13, and each tooth forms between two adjacent slot for windings 15.The rotating shaft 11 of rotor 12 rotatably is supported on the armature core 14.Therefore, change in the rotation of the tooth 16 of armature core 14 and the relative position between permanent magnet 13 magnetic poles according to rotor 12.
The expanded view of the common electric machine in Fig. 4 presentation graphs 3, it launches along X-X ' line and Y-Y ' line, and at this moment these lines become delegation.Armature core 14 has from a to 1,12 equating 30 ° of slot for windings that the angle is separated by, and 12 teeth are arranged between the two adjacent slot for windings, that is to say, T=12, overlapping winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 are centered around in the slot for winding a to 1.Each winding coil from A1 to C4 is around 3 teeth of armature core 14.That is, A1 is in slot for winding a and d, and A2 is in slot for winding d and g, A3 is in slot for winding g and j, A4 is in slot for winding j and a, and B1 is in slot for winding C and f, and B2 is in slot for winding f and i, B3 is in slot for winding i and l, B4 is around slot for winding l and c, and cl is in slot for winding e and h, and C2 is in slot for winding h and k, C3 is in slot for winding k and b, and C4 is in slot for winding b and e.Winding coil A1, A2, A3 and A4 are connected in series and form the first phase winding group A, and winding coil B1, B2, B3 and B4 are connected in series and form second mutually the winding group B, and winding coil C1, C2, C3 and C4 are connected in series and form the winding group C of third phase.Phase difference between winding group A, B and C equals 120el.In Fig. 3, P=4, so 180el equals 90 ° (mechanical angles), so the torque of accelerating rotor 2 relies on three-phase current is transported among three phase winding group A, B and the C and obtains.
A task of the present invention just provide one fabulous improved and reduced the efficient electric rotating machine of cogging torque.
Another task of the present invention provides such electric rotating machine, it have have T tooth, by the armature core of magnetic material system with have the N of the permanent magnetism that adds up to P and the excitation permanent magnet assembly of the S utmost point, (T is not less than 2P here) is with the characteristic that reduces the cogging torque relevant with the geometry of armature core and magnet.
According to the present invention, these tasks can be finished by electric rotating machine, it comprises: the excitation permanent magnet assembly and the armature core of magnetic materials of annular, described magnet assemblies has the N of permanent magnetization and the S utmost point and is centered around on the rotating shaft of electric rotating machine, the number of poles of the described N and the S utmost point is P, it is an even number, described armature core has many teeth that are arranged between two adjacent slot for windings, there, the overlapping winding coil of polyphase windings group is wrapped between cog, the described number of teeth is T, it is not less than 2P, the number of phases of described polyphase windings is H, it is not less than 2, described there armature core has a short element and long unit of paired appearance at least, they are arranged alternately on the circumference of described rotating shaft, has a short tooth on each described short element at least, at least one full-height tooth and not long tooth, has a described long tooth on each described long unit at least, at least one described full-height tooth and do not have above-mentioned short tooth, here, the effective pitch of described full-height tooth equals D=(360/T) degree, the effective pitch of each described short tooth is less than D, and the effective pitch of each described long tooth is greater than D.
These tasks of the present invention also can be finished as lower rotating electrical machine according to provided by the invention, it comprises: the excitation permanent magnet assembly and the armature core of magnetic materials of annular, described magnet assemblies has by the N of permanent magnetization and the S utmost point, they are arranged alternately on the rotating shaft of described electric rotating machine, the number of poles of the described N and the S utmost point is P, it is an even number, described armature core has many teeth that form between two adjacent slot for windings, the overlapping winding coil of the many polyphase windings groups in there is around between cog, the number of teeth of described tooth is T, it is not less than 2P, the number of phases of described polyphase windings group is H, it is not less than 2, and described slot for winding arranges with unequal angle, and the number of phases of described slot for winding in 1 pole span cycle that therefore has described magnet assemblies is greater than 2H.
These tasks of the present invention also can be finished according to following electric rotating machine provided by the invention, it comprises: the excitation permanent magnet assembly and the armature core of magnetic materials of annular, described magnet assemblies has the N and the S utmost point of permanent magnetization, and they are arranged alternately on the rotating shaft of described electric rotating machine, described N and S number of poles are P, it is an even number, described armature core has many teeth that form between two adjacent slot for windings, the overlapping winding coil of many polyphase windings groups is around between cog, the number of teeth of described tooth is T, it is not less than 2P, the number of phases of described heterogeneous coiling group is H, it is not less than 2, one of them described tooth has an extremely relative dead slot part with described magnet assemblies at least, between two adjacent described slot for windings and described dead slot part, form many tooth sections, described tooth hop count is T, T is greater than T, described armature core has a short element and long unit of paired appearance at least, they are arranged alternately on the circumference of described rotating shaft, each described short element has a short section at least, at least one standard paragraphs and long section, each described long unit has a described long section at least, at least one described standard paragraphs and short section, the effective pitch of standard paragraphs described here equals D=(360/Tt) degree; The effective pitch of each described short section is less than D, and the effective pitch of each described long section is greater than D.
Task of the present invention can be finished according to following electric rotating machine provided by the invention, it comprises: circular excitation permanent magnet assembly and armature core of magnetic materials, described magnet assemblies has the N and the S utmost point of permanent magnetization, they are arranged alternately on the rotating shaft of described electric rotating machine, the number of poles of the described N and the S utmost point is P, it is an even number, described armature core has many teeth that form between two adjacent slot for windings, here twining the overlapping winding coil of many polyphase windings groups, the number of teeth of described tooth is T, it is not less than 2P, the number of phases of polyphase windings group is H, it is not less than 2, here one of them described tooth has a dead slot part relative with the magnetic pole of described magnet assemblies at least at least, between two adjacent described slot for windings and described dead slot part, form many tooth sections, the hop count of described tooth section is Tt, it is greater than T, described slot for winding and described dead slot part arranges with unequal angle, and the number of phases that therefore has the described slot for winding in 1 pole span cycle of described magnet and described dead slot part is greater than 2H(Tt/T).
These and other task of the present invention and feature can become apparent with reference to being described in detail of accompanying drawing by following.Wherein:
Fig. 1 represents the diagrammatic cross-sectional view of the common electric rotating machine of T=6P;
Common electric rotating machine is along the expansion diagrammatic sketch of X-X ' line and Y-Y ' line in Fig. 2 presentation graphs 1;
Fig. 3 represents the diagrammatic cross-sectional view of another common electric rotating machine of T=3P;
Common electric rotating machine is along the expansion diagrammatic sketch of X-X ' line and Y-Y ' line in Fig. 4 presentation graphs 3;
Fig. 5 represents the diagrammatic cross-sectional view of the embodiment of T=6P electric rotating machine of the present invention;
The distribution of the magnetic flux density of the permanent magnet in Fig. 6 presentation graphs 5;
Electric rotating machine of the present invention is along the expansion view of X-X ' line and Y-Y ' line in Fig. 7 presentation graphs 5;
An electronic divider of the electric rotating machine shown in Fig. 8 presentation graphs 5;
Be fed to three-phase current I1, the I2 of three phase windings of electric rotating machine, the oscillogram of I3 in Fig. 9 presentation graphs 5;
Electric rotating machine of the present invention has the phase place of slot for winding of armature core in 1 pole span cycle of permanent magnet among Figure 10 presentation graphs 5 and Fig. 7;
The synthesizing magnetic variation diagram of electric rotating machine of the present invention among Figure 11 presentation graphs 5 and Fig. 7;
The synthesizing magnetic variation diagram of common electric rotating machine among Figure 12 presentation graphs 1 and Fig. 2;
Figure 13 (a) is to other spread pattern of (d) expression slot for winding of armature core shown in Fig. 5 according to the present invention;
Figure 14 represents the cross-sectional sketch of looking of another embodiment of the electric rotating machine of T=3P of the present invention;
Figure 15 represents that electric rotating machine of the present invention is along the expansion view of X-X ' line and Y-Y ' line among Figure 14;
Figure 16 represents that electric rotating machine of the present invention among Figure 14 and Figure 15 has the phase place of slot for winding of armature core in 1 pole span cycle of permanent magnet;
Figure 17 represents the synthesizing magnetic variation diagram of electric rotating machine of the present invention among Figure 14 and Figure 15;
The synthesizing magnetic variation diagram of common electric rotating machine among Figure 18 presentation graphs 3 and Fig. 4;
Figure 19 (a) to (d) represents according to the present invention other spread pattern of the slot for winding of armature core among Figure 14;
Figure 20 is the cross-sectional sketch of looking of further embodiment of the electric rotating machine of expression T=3P of the present invention;
Figure 21 represents that electric rotating machine of the present invention is along the expansion diagrammatic sketch of X-X ' line and Y-Y ' line among Figure 20;
Figure 22 is the slot for winding and the dead slot phase place partly of the armature core in the 1 pole span cycle that electric rotating machine of the present invention has permanent magnet among expression Figure 20 and Figure 21;
Figure 23 is the synthesizing magnetic variation diagram of electric rotating machine of the present invention among expression Figure 20 and Figure 21;
Figure 24 (a) is to the slot for winding of (d) expression armature core among Figure 20 according to the present invention and other spread pattern of dead slot part.
" embodiment of the invention of T=6P "
Fig. 5, Fig. 6, Fig. 7, Fig. 8 and Fig. 9 represent the brshless DC motor of T=6P of the present invention, and it is corresponding with the common electric rotating machine shown in Fig. 1 and Fig. 2.Fig. 5 represents the cross-sectional sketch of looking of brshless DC motor of the present invention.In Fig. 5, a cylindrical shape permanent magnet 23 is fixed on the excircle of the rotor of being made by magnetic material 22, and permanent magnet 23 and rotor 22 rotate together around rotating shaft 21.Permanent magnet 23 has 4 N that are arranged alternately and the S utmost point and 90 ° of angles layouts to be equal to, that is, P=4, P is the number of magnetic poles of permanent magnet 23 here.Fig. 6 represents the distribution of the magnetic flux density of permanent magnet 23.The tooth 26 of the armature core 24 that each forms between two adjacent slot for windings 25 is relative with the magnetic pole of permanent magnet 23.Armature core 24 is supporting the rotating shaft 21 of rotor 22 rotatably.Therefore, the relative position between the magnetic pole of armature core 24 teeth 26 and permanent magnet 23 changes according to the rotation of rotor 22.
Brshless DC motor of the present invention is along the expansion diagrammatic sketch of X-X ' and Y-Y ' line in Fig. 7 presentation graphs 5, and at this moment these lines become delegation.Armature core 24 has 24 slot for winding a, b, c, d, e, f, g, h, i, j, k, l, m, n, o, p, q, r, s, t, u, v, w and x, and 24 be arranged on tooth between the two adjacent slot for windings, promptly, T=24, T is the number of teeth of armature core 24 here.Overlapping winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 are wrapped in slot for winding a in x.Each winding coil from A1 to C4 is around the tooth of 5 armature cores 24.Be that A1 is centered around in slot for winding a and the f, A2 is centered around in slot for winding g and the l, and A3 is centered around in slot for winding m and the r, and A4 is centered around in slot for winding S and the x, B1 is centered around in slot for winding e and the j, B2 is centered around in slot for winding k and the p, and B3 is centered around in slot for winding q and the v, and B4 is centered around in slot for winding w and the d, C1 is centered around in slot for winding i and the n, C2 is centered around in slot for winding o and the t, and C3 is centered around in slot for winding u and the b, and C4 is centered around in slot for winding c and the h.Winding coil A1, A2, A3 and A4 are connected in series and form first mutually the winding group A, winding coil B1, B2, B3 and B4 are connected in series and form second mutually the winding group B, and winding coil C1, C2, C3 and C4 are connected in series and form the winding group C of third phase.As described below, the phase difference between winding group A, B and the C equals the 120el(electrical degree just), 180el equals 1 pole span of 360/P degree here.In Fig. 5, P=4, so, 180el equals 90 degree (mechanical angle), and it is identical with the common electric machine shown in Fig. 1.Therefore, the torque of accelerating rotor 22 can obtain by three-phase current being transported among three phase winding group A, B and the C.
Fig. 8 represents the electronic divider 30 of brshless DC motor of the present invention.Electronic divider 30 has an exciter 31 and a position sensor 32, and it is transported to three phase winding group A of Y-connection to three-phase current I1, I2 and I3 respectively, among B and the C.The relative position that position sensor 32 detects between armature core 24 and the permanent magnet 23, it exports three-phase sinusoidal signal P1, P2 and P3, by the magnetic flux that detects permanent magnet 23 these signals are changed with the rotation one of rotor 22, exciter 31 output three-phase current I1, I2 and I3, these electric currents are directly proportional with the command signal F of amplifying signal P1, P2, P3 respectively.Like this, the torque of accelerating rotor 22 can and be transported to three-phase current I1, the I2 of winding group A, B and C and the interaction between the I3 and producing by the magnetic flux of permanent magnet 23.To describe the electromagnetic torque that produces by three-phase current below in detail.
In Fig. 7, because the slot for winding from a to x is arranged with the angle that does not wait, the effective pitch of tooth is inequality, here the effective pitch of a tooth is represented by the angle between the two slot for winding centers that form tooth, at T=6P=24(P=4) example in, when all slot for windings were arranged by angle same, the effective pitch of standard was D=(360/T)=15 degree.So the tooth that effective pitch equals D is called full-height tooth, the tooth that effective pitch ratio D is little is called short tooth, and the tooth that effective pitch ratio D is big is called long tooth.A tooth is represented by the slot for winding that forms tooth.For example, tooth a-b means that this tooth is formed by slot for winding a and b.In Fig. 7, tooth a-b, c-d, d-e, f-g, g-h, i-j, j-k, k-l, l-m, m-n, o-p, p-q, r-s, s-t, u-v, v-w, w-x and x-a are full-height tooths, and tooth b-c, e-f and h-i are long teeth, and tooth n-o, q-r and t-u are short teeth.In Fig. 7 and other figure, full-height tooth, long tooth and short tooth are represented by E, R and Z respectively.
Order at least one short tooth, at least one full-height tooth are set and not the unit of long tooth be called short element, order is provided with at least one long tooth, at least one full-height tooth and the unit of not short tooth is called long unit, the unit is represented by the slot for winding that is arranged on the both sides, unit.For example, unit＜a, m〉mean the unit of tooth a-b, b-c, c-d, d-e, e-f, f-g, g-h, h-i, i-j, j-k, k-l and l-m.In Fig. 7, armature core 24 only has a pair of long unit＜a, m〉and short element＜m, a, they are arranged alternately around rotating shaft 21.Long unit＜a, m〉3 long tooth b-c, e-f and h-i and 9 full-height tooth a-b, c-d, d-e, f-g, g-h, i-j, j-k, k-l and l-m are arranged.Short element＜m, a〉3 short tooth n-o, q-r and t-u and 9 full-height tooth m-n, o-p, p-q, r-s, s-t, u-v, v-w, w-x and x-a are arranged.Attention: discrimination unit is not to depend on the number of teeth, but the feature that tooth had.Should also be noted that full-height tooth between adjacent long tooth and short tooth can belong to long unit and also can belong to short element, because it is unimportant distinguishing when having a long unit or short element.In the embodiment of Fig. 7, at long unit＜a, m〉in the number of teeth select to equal short element＜m, a in the number of teeth.
Each effective pitch of long tooth b-c, e-f and h-i equals or the approaching D(1+1/P that equals)=18.75 degree, each effective pitch of short tooth n-o, q-r and t-u equals or the approaching D(1-1/P that equals)=11.25 degree.Therefore, long unit＜a, m〉whole effective pitch be 191.25 degree, short element＜m, a〉whole effective pitch be 168.75 degree.
Below with the cogging torque of the embodiment of the invention shown in the key-drawing 5.Cogging torque is to be produced by the interaction between permanent magnet and the armature core, particularly by changing owing to be stored in magnetic energy in the air gap when relatively rotating between permanent magnet and the armature core.This torque is a basic cycle (1 circle) to do periodically to change according to its relative position with 360 degree, and therefore, this steady rotation to electric rotating machine is harmful to.Cogging torque is subjected in the face of the shape of the armature core of permanent magnet and the influence that distributed by the magnetic charge on the permanent magnet poles.The shape of armature core is to be that the shape harmonic wave of Fourier expansion of basic cycle is represented by having 360 degree, and the shape harmonic wave is suitable for the shape of armature core.The distribution of magnetic charge is that the magnetic distribution harmonic wave of Fourier expansion of basic cycle represents that magnetic distribution harmonic wave is relevant with the distribution of magnetic charge in the permanent magnet by having 360 degree.
On mathematics, cogging torque is by the convolution between shape harmonic wave and magnetic distribution harmonic wave decision, also is simultaneously by having the Fourier expansion that 360 degree are the basic cycle.The value of each part (cycle/revolution) of cogging torque is to be directly proportional with the shape harmonic component of the same number of degrees of cogging torque with as the product of magnetic distribution harmonic component.
Because the magnetic energy of air gap is directly proportional with the square value of the magnetic flux density of permanent magnet.The distribution of the magnetic flux density shown in Fig. 6 and polar-symmetric.The magnetic distribution harmonic wave of permanent magnet 23 is one and has the periodic function that 1 pole span (360/P)=90 is spent the cycle.Therefore, when the synthesizing magnetic of the shape harmonic wave of the armature core 24 with 1 pole span cycle diminished, cogging torque was also along with diminishing.
Figure 10 represents to have a of armature core 24 in 1 pole span cycle of permanent magnet 23 to the slot for winding phase place of x.Slot for winding a, b, g, l, m, r, s and x arrange with the phase difference of (1 pole span)/24, are twining winding coil A1, A2, A3 and the A4 of winding group A in described slot for winding.Promptly; The phase place of slot for winding a, f, g, l, m, r, s and x differs (1 pole span)/24 each other, and the phase range of slot for winding a, f, g, l, m, r, s and x is in (1 pole span)/3.Similarly, slot for winding d, e, j, k, p, q, v and w arrange with the phase difference of (1 pole span)/24, twining winding coil B1, B2, B3 and the B4 of winding group B in these grooves, the phase range of slot for winding d, e, j, k, p, q, v and w is within (1 pole span)/3.Similarly, slot for winding b, c, h, i, n, o, t and u arrange with the phase difference of same (1 pole span)/24, twining winding coil C1, C2, C3 and the C4 of winding group c in these grooves, the phase range of slot for winding b, c, h, i, n, o, t and u is within (1 pole span)/3.Furtherly, the phase difference between the slot for winding group (b, c, h, i, n, o, t, n) of the slot for winding group (d, e, j, k, p, q, v, w) of slot for winding group (a, f, g, l, m, r, s, x) the winding group B of winding group A and winding group C equals (1 pole span)/3 just.Because this result, the phase difference between three phase winding group A, B and C equals 120el just.
The phase difference of all slot for windings from a to x is (1 pole span)/24 each other, and people's expectation has the synthetic magnetic variable in 1 pole span cycle and diminishes.Figure 11 represents that the magnetic from a to the x slot for winding changes the waveform of the synthetic magnetic variable TV of waveform and armature core 24.The magnetic variable of each slot for winding becomes very little with respect to each A/F smooth change, because the phase place of slot for winding is separated by with (1 pole span)/24 so synthesize magnetic variable TV.
The waveform of the synthetic magnetic variable TV ' of the armature core 4 of the common electric rotating machine shown in Figure 12 presentation graphs 1 and Fig. 2.In the example of common electric rotating machine, the phase place of slot for winding a, g, m and s is identical with 1 pole span cycle, the phase place of slot for winding b, h, n and t is identical, the phase place of slot for winding c, i, o and u is identical, the phase place of slot for winding d, j, p and v is identical, and the phase place of slot for winding e, k, q and w is identical, and the phase place of slot for winding f, l, r and x is identical, so it is greatly that synthesizing magnetic changes TV '.The synthesizing magnetic that synthesizing magnetic among Figure 11 is changed among TV and Figure 12 changes TV ' comparison, and the TV of motor of the present invention is more much smaller than the TV ' of common electric machine.Therefore, the embodiment of the brshless DC motor of the present invention shown in Fig. 5 has very little cogging torque.
Be described in the electricity-magnetic torque of the brshless DC motor of the present invention shown in Fig. 5, Fig. 6, Fig. 7, Fig. 8 and Fig. 9 below.Electricity-magnetic torque be by three-phase current I1, I2 and I3 be passed to three phase winding group A, B and torque that C produces and, entering each torque that three phase winding group A, B and C are produced by each electric current I 1, I2 and I3 is the product of electric current and magnetic flux density.Therefore, electricity-magnetic torque Tor is
Tor＝G
x（B
aI1+B
bI2+B
cI3）……（1）
In the formula: Gx is a constant.
B
a, B
bAnd B
cIt is respectively the equivalent magnetic flux density of three phase winding group A, B and C.Here the distribution of supposing permanent magnet 23 is a sine curve, promptly
B（X）＝Blsin（X）
In the formula: x is an angle (electrical degree).So, Deng Xiao magnetic flux density B
a, B
bAnd B
cAlso become sine curve, promptly
B
a（z）＝kB
1Sin（z）……（3a）
B
b（z）＝kB
1Sin（z-120el）……（3b）
B
c（z）＝kB
1Sin（z-240el）……（3c）
In the formula: k is that a constant and z are the relative angles (electrical degree) between the reference point of the reference point of armature core 24 and permanent magnet 23.Because three-phase current I1, I2 and I3 are sine curves,
I
1（z）＝I
pSin（z）……（4a）
I
2（z）＝I
pSin（z-120el）……（4b）
I
3（z）＝I
pSin（z-240el）……（4c）
In the formula: I
pIt is the peak current that and instruction signal F is directly proportional.So the torque of generation becomes
Tor＝（3/2）（G
xk）BlI
p……（5）
Electricity-magnetic torque Tor of this embodiment is the torque that does not have fluctuation stably.
But the actual distribution of permanent magnet 23 shown in Figure 6 has the higher components of the 3rd, 5,7 grades.These higher components particularly the 3rd, 5,7 time, produce the fluctuation torque, (and the fluctuation torque stops the smooth operation of motor) and cogging torque.Because the phase phasic difference (1 pole span)/3 of the slot for winding of each winding A, B or C is so useful flux density B, the B and the B that equate have reduced the 3rd, 5,7 component of degree n ns.The magnetic flux distribution of supposing permanent magnet 23 is
B（x）＝B1Sin（x）+B3Sin（3x）+B5Sin（5x）+B7Sin（7x）……（6）
So, Deng Xiao magnetic flux density B
a, B
bAnd B
cBecome
B
a（z）＝k｛k1B1Sin（z）+k3B3Sin（3z）+k5B5Sin（5z）+k7B7Sin（7z）｝
……（7a）
B
b（z）＝B
a（z-120el）……（7b）
B
c（z）＝B
a（z-120el）……（7c）
In the formula: k1=0.956, k3=0.641, k5=0.194, k7=-0.141, k1/k1=1(standard), k3/k1=0.67, k5/k1=0.20, k7/k1=-0.15.
Because k3/k1, the ratio of k5/k1 and k7/k1 absolute value are less than 1, the influence of the higher components B3 of permanent magnet 23, B5, B7 is reduced and the brshless DC motor of described embodiment fluctuation torque diminishes.Therefore, Fig. 5 is little to the cogging torque and the fluctuation torque of the brshless DC motor of the present invention shown in Fig. 9, thereby can obtain smooth operation.
Winding coil A1, the A2 of armature core 24, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4 can be twined automatically by coil winding machine among the described embodiment, because the winding pitch of these winding coils no better than permanent magnet 23 1 pole span 5/6, here, the winding pitch of a winding coil is the angle at center between two slot for windings, is twining winding coil in the groove.These winding coils A1 to the winding pitch of C4 between 135el and 165el.Exactly, the winding pitch of winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4 is respectively 165el, 157.5el, 135el, 142.5el, 165el, 142.5el, 135el, 157.5el, 150el, 142.5el, 150el and 157.5el.
In described embodiment, use an electronic divider that heterogeneous sinusoidal current is provided as the polyphase windings group, therefore, the electronic divider shown in Fig. 8 can replace the brusher transducer but the formation of distributor does not relate to cogging torque (it only relates to the fluctuation torque).In addition, though permanent magnet 23 is continuous circumferential in Fig. 5 or other figure, in the present invention, also can use the magnet of gapped therebetween separation segmentation.
As mentioned above, the cogging torque of electric rotating machine of the present invention is little.In general, the electric rotating machine that comprises columniform excitation permanent magnet assembly and magnetic material armature core just can reduce cogging torque, described magnet assemblies has by the N and the S utmost point around the machine shaft arranged alternate of permanent magnetization, the number of poles of the N and the S utmost point is P, it is an even-integral number, described armature core has many teeth that form between two adjacent slot for windings, in these slot for windings, twining the overlapping winding coil of many polyphase windings groups, the described number of teeth is T, it is not less than 2P, the number of phases of described polyphase windings group is H, and it is not less than 2, has a pair of long unit and short element around the rotating shaft arranged alternate on described armature core at least.Each described short element has a short tooth at least, at least one full-height tooth, and not long tooth, each described long unit has a long tooth at least, at least one full-height tooth, and not short tooth, the effective pitch of described full-height tooth equals D=(360/T) degree, the effective pitch of each described short tooth is not more than D, and the effective pitch of each described long tooth is greater than D.
Preferably select the whole effective pitch of a pair of described adjacent short element and long unit to equal or approaching (360/P) Q degree that equals, here Q is not less than 2 integer, the effective pitch of each short tooth in described a pair of adjacent short element and long unit equals or the approaching D(1-J/Q that equals) degree, the effective pitch of each long tooth in above-mentioned a pair of adjacent short element and long unit equals or the approaching D(1+G/Q that equals) spend, here J and G are not less than 1 but be not more than the integer of Q/2, are preferably J=G=1.Also can select the quantity of the short-and-medium tooth of described short element to be not less than 2, the quantity of long tooth is not less than 2 in described long unit, also can select the quantity of the short-and-medium tooth of described short element to equal the quantity of the long tooth in described long unit, and it is less than Q and preferably hank and equal Q-1.The both sides that also can select each described long tooth are adjacent with two described full-height tooths, and the both sides of each described short tooth are adjacent with two described full-height tooths.
Other structure that reduces the electric rotating machine of the present invention of cogging torque arrives 13(d at Figure 13 (a)) shown in.Figure 13 (a) has represented the slot for winding a of armature core 24 among Fig. 5 and Fig. 7 other spread pattern to x.The position of long tooth, short tooth and full-height tooth is different with the armature core 24 among Fig. 7.Be that tooth e-f, f-g and g-h are long teeth, tooth m-n, r-s and w-x are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element, as, long unit＜a, m〉and short element＜m, a.The effective pitch of long tooth equals D(1+1/P)=18.75 degree, the effective pitch of short tooth equals D(1-1/P)=11.25 degree.So, Q=P=4, G=1 and J=1.
The slot for winding a of armature core 24 is to another spread pattern of x among Figure 13 (b) presentation graphs 5 and Fig. 7.The position of long tooth, short tooth and full-height tooth is different from the armature core 24 among Fig. 7.Be that tooth b-c, c-d and h-i are long teeth, tooth n-o, o-p and t-u are short teeth, and other tooth is a full-height tooth, and armature core only has a pair of long unit and short element.For example, long unit＜a, m〉and short element＜m, a.The effective pitch of long tooth equals D(1+1/P)=18.75 degree, the effective pitch of short tooth equals D(1-1/P)=11.25 degree.So, Q=P=4, G=1 and J=1.
The slot for winding a of armature core 24 is to other spread pattern of x among Figure 13 (c) presentation graphs 5 and Fig. 7.The position of long tooth, short tooth and full-height tooth is different from armature core 24 among Fig. 7.Be that tooth f-g and l-m are long teeth, tooth r-s and x-a are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element.For example, long unit＜a, m〉and short element＜m, a.The effective pitch of long tooth f-g equals D(1+2/P)=22.5 degree, the effective pitch of long tooth l-m equals D(1+1/P)=18.75 degree.The effective pitch of short tooth r-s equals D(1-2/P)=7.5 degree.The effective pitch of short tooth x-a equals D(1-1/P)=11.25 degree.So, Q=P=4, G=1 or 2, J=1 or 2.
The slot for winding a of armature core 24 is to other spread pattern of x among Figure 13 (d) presentation graphs 5 and Fig. 7.The position of long tooth, short tooth and full-height tooth is different from the armature core 24 among Fig. 7.Be that tooth f-g and h-i are long teeth, tooth n-o, r-s and x-a are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element.For example, long unit＜a, m〉and short element＜m, a.The effective pitch of long tooth f-g equals D(1+2/P)=22.5 degree.The effective pitch of long tooth h-i equals D(1+1/P)=18.75 degree, the effective pitch of short tooth n-o, r-s and x-a equals D(1-1/P)=11.25 degree.So, Q=P=4, G=1 or 2, J=1.
In Figure 13 (d), the quantity of long tooth is not equal to the quantity of short tooth.In general, the electric rotating machine that comprises cylindrical excitation permanent magnet assembly and magnetic material armature core can reduce cogging torque, described magnet assembly has the N and the S utmost point that are arranged alternately around the rotating shaft of electric rotating machine of permanent magnetization, the number of poles of N and S is P, it is an even number, described armature core has many teeth that form between two adjacent slot for windings, twining the overlapping winding coil of many group polyphase windings in these grooves.The number of teeth of described tooth is T, and it is not less than 2P, and the number of phases of described polyphase windings group is H, and it is not less than 2, and described slot for winding is with not equal angles setting, so that the number of phases of described slot for winding in 1 pole span cycle with described magnet assemblies is greater than 2H.
Preferably make the phase place of all slot for windings in 1 pole span cycle differ the isogonism of (1 pole span)/T each other with described permanent magnet assembly.
The embodiment of the invention of T=3P.
Figure 14 and Figure 15 represent the brshless DC motor that the present invention of T=3P is other, and it is corresponding with the common electric rotating machine shown in Fig. 3 and Fig. 4.Figure 14 is the cutaway view of brshless DC motor of the present invention.In Figure 14, cylindrical shape permanent magnet 43 is fixed on the excircle of rotor 42 of magnetic material, and permanent magnet 43 and rotor 42 rotate around axle 41 together.Permanent magnet 43 has 4 N and the S utmost point, the i.e. P=4 that are spaced from each other 90 degree and are arranged alternately.The magnetic flux distribution of permanent magnet 43 identical with shown in Fig. 6.The tooth 46 of armature core 44 is relative with the magnetic pole of permanent magnet 43, and each tooth forms between two adjacent slot for windings 45.The rotating shaft 41 of rotor 42 rotatably is supported on the armature core 44.Therefore, the relative position between the magnetic pole of the tooth 46 of armature core 44 and permanent magnet 43 changes according to the rotation of rotor 42.
Figure 15 represents that brushless direct-current electric rotating machine of the present invention is along the expansion diagrammatic sketch of X-X ' line with Y-Y ' line (at this moment these lines become delegation) among Figure 14.Armature core 44 has 12 slot for winding a, b, c, d, e, f, g, h, i, j, k and l, and 12 teeth that are arranged between the two adjacent slot for windings, i.e. T=12.Overlapping winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4.Be wrapped in the slot for winding from a to l.Each winding coil from A1 to C4 is around 3 teeth of armature core 44.Be that A1 is in slot for winding a and d, A2 is in slot for winding d and g, A3 is in slot for winding g and j, A4 is in slot for winding j and a, B1 is in slot for winding c and f, B2 is in slot for winding f and i, B3 is in slot for winding i and l, and B4 is in slot for winding l and c, and C1 is in slot for winding e and h, C2 is in slot for winding h and k, C3 in slot for winding k and b, C4 in slot for winding b and e, winding coil A1, A2, A3 and A4 are connected in series and form first mutually the winding group A, winding coil B1, B2, B3 and B4 are connected in series and form the second phase winding group B, winding coil C1, C2, C3 and C4 are connected in series and form third phase winding group C.As described below, the phase difference between winding group A, B, the C equals the 120el(electrical degree just), 180el equals 1 pole span (360/P) degree here.In Figure 14, P=4,180el equals 90 degree (mechanical angle) so, and it is identical with common electric machine among Fig. 3.Therefore, can obtain the torque of accelerating rotor 42 by means of three-phase current being infeeded three phase winding group A, B and C.Electronic divider 30 shown in Figure 8 also may be used in the brshless DC motor of the present invention of Figure 14.
In Figure 15, because the slot for winding from a to l arranges that with different angles the effective pitch of tooth is inequality.At T=3P=12(P=4) example in, when all slot for windings were arranged with equal angles, the effective pitch of standard was D=(360/T)=30 the degree.So the effective pitch of full-height tooth equals D, the effective pitch of short tooth is less than D, and the effective pitch of long tooth is greater than D.In Figure 15, tooth a-b, b-c, d-e, g-h, h-i and j-k are full-height tooths, and tooth c-d, e-f and f-g are long teeth, and tooth i-j, k-l and l-a are short teeth.Armature core 44 only has a pair of long unit＜a, g〉and short element＜g, a and be arranged alternately around rotating shaft 41.Long unit＜a, g〉3 long tooth c-d, e-f and f-g and 3 full-height tooth a-b, b-c and d-e arranged.Short element＜g, a〉3 short tooth i-j, k-l and l-a and 3 full-height tooth g-h, h-i and j-k arranged.
Each effective pitch of long tooth c-d, e-f and f-g equals or the approaching D(1+1/P that equals)=37.5 degree, the effective pitch of short tooth i-j, k-l and l-a equals or the approaching D(1-1/P that equals)=22.5 degree.Like this, long unit＜g, a〉whole effective pitch be 202.5 degree, short tooth＜g, a〉whole effective pitch be 157.5 degree.
The following describes the cogging torque of the embodiment of the invention shown in Figure 14.Figure 16 represents to have the phase place of armature core 44 from a to the l slot for winding in 1 pole span cycle of permanent magnet 43.Slot for winding a, d, g and j are twining winding coil A1, A2, A3 and the A4 of winding group A with the phase difference setting of (1 pole span)/12 in the slot for winding.The phase place that is slot for winding a, d, g and j differs (1 pole span)/12 mutually, and the phase range of slot for winding a, d, g and j is within (1 pole span)/3.Similarly, slot for winding c, f, i and l arrange with identical phase difference (1 pole span)/12, are twining winding coil B1, B2, B3 and the B4 of winding group B in slot for winding.And the phase range of slot for winding c, f, i and l is within (1 pole span)/3.Similarly, slot for winding b, e, h and k arrange with identical phase difference (1 pole span)/12, are twining winding coil C1, C2, C3 and the C4 of winding group C in slot for winding.The phase range of slot for winding b, e, h and k is within (1 pole span)/3.Furtherly, the slot for winding group of winding group A (a, d, g, j), the phase difference of the slot for winding group (b, e, h, k) of the slot for winding group of winding group B (c, f, i, l) and winding group C is (1 pole span)/3 just.Because this result, the phase difference between three phase winding A, B and the C equals the 120el degree just, uses the distributor 30 of Fig. 8 can steadily be changeed distance.
All phase phasic differences (1 pole span)/12 of slot for winding from a to l, people's expectation has the synthesizing magnetic in 1 pole span cycle and diminishes.The synthesizing magnetic that Figure 17 has represented from a to l slot for winding magnetic to change waveform and armature core 44 changes the waveform of TV.The magnetic of each slot for winding changes and steadily changes with respect to each A/F.Because the phase phasic difference of slot for winding (1 pole span)/12 is so it is very little that synthesizing magnetic becomes.
The synthesizing magnetic of the common rotary motor armature iron core 14 shown in Figure 18 presentation graphs 3 and Fig. 4 changes the waveform of TV '.In the example of common electric rotating machine, the phase place of slot for winding a, d, g and j is identical with 1 pole span cycle, and the phase place of slot for winding b, e, h and k is identical, and the phase place of slot for winding c, f, i and l is identical.So synthesizing magnetic changes TV ' greatly.Relatively the synthesizing magnetic among Figure 17 changes the synthetic property variation TV ' of TV and Figure 18, and the TV of motor of the present invention is more much smaller than the TV ' of common electric machine.Therefore, the embodiment of the brshless DC motor of the present invention shown in Figure 14 has very little cogging torque.
Winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and the C4 of the armature core 44 in described embodiment can be twined automatically by coil winding machine, because the winding pitch of these winding coils 1 pole span of permanent magnet 43 no better than.These winding coils A1 is between 150el and 210el to the winding pitch of C4.Or rather, the winding pitch of winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 is respectively 195el, 210el, 165el, 150el, 210el, 195el, 150el, 165el, 210el, 165el, 150el and 195el.
Other structures with the electric rotating machine of the present invention that reduces cogging torque are shown in Figure 19 (a) to 19(d), another spread pattern of the slot for winding of armature core 44 from a to l among Figure 19 (a) expression Figure 14 and Figure 15, the position of long tooth, short tooth and full-height tooth is different from the armature core 44 of Figure 15, be that tooth a-b, b-c and c-d are that long tooth, tooth f-g, h-i and j-k are short teeth, other tooth is a full-height tooth.Armature core only has a pair of long unit and short element, for example, and long unit＜a, f〉and short element＜f, a.The effective pitch of long tooth equals D(1+1/P)=37.5 degree, the effective pitch of short tooth equals D(1-1/P)=22.5 degree.So Q=P=4, G=1 and J=1.
Slot for winding a is to another arrangement mode of l on the armature core 44 shown in Figure 19 (b) expression Figure 14 and Figure 15.Long tooth, the position of short tooth and full-height tooth is different from the armature core 44 of Figure 15.Be that tooth b-c, d-e and f-g are long teeth, tooth i-j, j-k and k-l are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a, the effective pitch of long tooth equals D(1+1/P)=37.5 degree; The effective pitch of short tooth equals D(1-1/P)=22.5 degree.So, Q=P=4, Q=1 and J=1.
Slot for winding a is to another arrangement mode of l on the armature core 44 shown in Figure 19 (c) expression Figure 14 and Figure 15.The position of long tooth, short tooth and full-height tooth is different from the armature core 44 of Figure 15.Be that tooth c-d and f-g are long teeth, tooth i-j and l-a are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a.The effective pitch of long tooth c-d equals D(1+2/P)=45 degree, the effective pitch of long tooth f-g equals D(1+1/P)=37.5 degree, the effective pitch of short tooth i-j equals D(1-2/P)=15 degree, the effective pitch of short tooth l-a equals D(1-1/P)=22.5 degree, so, Q=P=4, G=1 or 2, J=1 or 2.
Slot for winding a is to other arrangement mode of l on the armature core 44 shown in Figure 19 (d) expression Figure 14 and Figure 15.The position of long tooth, short tooth and full-height tooth is different from the armature core 44 of Figure 15.Be that tooth c-d and d-e are long teeth, tooth g-h, i-j and l-a are short teeth, and other tooth is a full-height tooth.Armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a.The effective pitch of long tooth c-d equals D(1+2/P)=45 degree, the effective pitch of long tooth d-e equals D(1+1/P)=37.5 degree, the effective pitch of short tooth g-h, i-j and l-a equals D(1-1/P)=22.5 degree.So, Q=P=4, G=1 and 2, J=1.
Figure 20 and Figure 21 represent another brshless DC motor of the present invention of T=3P, and it is also corresponding with Fig. 3 and common electric rotating machine shown in Figure 4.Figure 20 is the simple cutaway view of brshless DC motor of the present invention.In Figure 20, a cylindrical shape permanent magnet 53 is fixed on the excircle of the rotor of being made by magnetic material 52, and permanent magnet 53 rotates around rotating shaft 51 with rotor 52.Permanent magnet 53 has 4 N and the S utmost points of being separated by and being arranged alternately with an angle of 90 degrees that equates, i.e. P=4, the distribution of the magnetic flux density of permanent magnet 53 identical with shown in Fig. 6.The tooth 56 of armature core 54 is in the face of the magnetic pole of permanent magnet 53, and each tooth forms between two adjacent slot for windings 55.The rotating shaft 51 of rotor 52 rotatably is supported on the armature core 54.Therefore, the relative position between the magnetic pole of the tooth 56 of armature core 54 and permanent magnet 53 changes according to the rotation of rotor 52.
Figure 21 represents that brshless DC motor of the present invention is along the expansion diagrammatic sketch of X-X ' line with Y-Y ' line (when these lines become delegation) among Figure 20, armature core 54 has 12 slot for winding a, b, c, d, e, f, g, i, j, k and l, and 12 teeth that between two adjacent slot for windings, form, i.e. T=12.Armature core 53 also has 12 at the surface of tooth and permanent magnet 53 relative dead slot part a ', b ', c ', d ', e ', f ', g ', h ', i ', j ', k ' and l ', do not have coil be wrapped in dead slot partly in.The dead slot part is counted Td=12, and overlapping winding coil A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3 and C4 are wrapped in the slot for winding from a to l.Tooth from A1 to each winding coil of C4 around 3 armature cores 54.Be that A1 is in slot for winding a and d, A2 is in slot for winding d and g, and A3 is in slot for winding g and j, and A4 is in slot for winding j and a, B1 is in slot for winding c and f, B2 is in slot for winding f and i, and B3 is in slot for winding i and l, and B4 is in slot for winding l and c, C1 is in slot for winding e and h, C2 is in slot for winding h and k, and C3 is in slot for winding k and b, and C4 is in slot for winding b and e.Winding coil A1, A2, A3 and A4 are connected in series and form first mutually winding group A, winding coil B1, B2, B3 and the B4 and be connected in series and form second mutually the winding group B, and winding coil C1, C2, C3 and C4 are connected in series and form the winding group C of third phase.Phase difference between winding group A, B and the C is the 120el(electrical degree just), 180el equals 1 pole span (360/P) degree here.In Figure 20, P=4, so 180el equals 90 degree (mechanical angle), it with Fig. 3 in common electric machine identical.Therefore, the torque of accelerating rotor 52 can obtain by three-phase current being transported among three phase winding group A, B and the C.Electronic divider 30 shown in Fig. 8 can use in Figure 20 brshless DC motor of the present invention equally.
Armature core 54 has 24 tooth sections, and each tooth section all is to form in the middle of the dead slot part of l ' at two adjacent slot for winding from a to l and a '.In Figure 21, because slot for winding a arrives the angle setting of l ' not wait to l and dead slot part a ', so the effective pitch of tooth section is also inequality.In the example of Tt=T+Td=24, when all slot for windings and dead slot part was provided with angle same, the standard effective pitch of tooth section was D=(360/Tt)=15 degree.So, the tooth section that effective pitch equals D is called the full-height tooth section, effective pitch is called short tooth section less than the tooth section of D, and effective pitch is called long tooth section greater than the tooth section of D, and the tooth section is represented by two slot for winding and two dead slots that constitute it.For example, tooth section a-a ' means that this tooth section is formed by slot for winding a and dead slot a '.In Figure 21, tooth section a-a ', b-b ', b '-c, c '-d, d-d ', e-e ', e '-f, f-f ', f '-g, g-g ', h-h ', h '-i, i '-j, j-j ', k-k ', k '-l, l-l ' and l '-a are the full-height tooth sections, tooth section a '-b, c-c ' and d '-e are long tooth sections, and tooth section g '-h, i-i ' and j '-k are short tooth sections.In Figure 21 and other figure, the full-height tooth section, long tooth section and short tooth section are respectively by E ', R ' and Z ' expression.
Order at least one long tooth section, at least one full-height tooth section are set and not the unit of short tooth section be called long unit, order is provided with at least one and lacks tooth section, at least one full-height tooth section and the unit of not long tooth section is called short element.A unit is partly represented by slot for winding that is arranged on these both sides, unit or dead slot.Armature core 54 for example only has a pair of long unit that is arranged alternately around rotating shaft 51 and short element, long unit＜a, f '〉and short element＜f ', a.Long unit＜a, f '〉3 long tooth section a '-b, c-c ' and d '-e and 8 full-height tooth section a-a ', b-b ', b '-c, c '-d, d-d ', e-e ', e '-f and f-f ' are arranged.Short element＜f ', a〉3 short tooth section g '-h, i-i ' and j '-k and 10 full-height tooth section f '-g, g-g ', h-h ', h '-i, i '-j, j-j ', k-k ', k '-l, l-l ' and l '-a are arranged.Each effective pitch of long tooth section a '-b, c-c ' and d '-e equals or the approaching D(1+1/P that equals)=18.75 degree, each effective pitch of short tooth section g '-h, i-i ' and j '-k equals or the approaching D(1-1/P that equals)=11.25 degree.The full-height tooth section that is provided with between adjacent long tooth section and short tooth section can belong to long unit or short element.It is unimportant because when distinguishing existence one long unit or short element.
To narrate the cogging torque of the embodiment of the invention shown in Figure 20 below.Figure 22 represent armature core 54 from a to the l slot for winding and dead slot part a ' to the phase place of l ' and 1 pole span cycle of permanent magnet 53.Twining slot for winding a, d, g and j dead slot part a ', d ', g ' and the j ' of winding coil A1, A2, A3 and the A4 of winding group A phase difference setting with (1 pole span)/24.Be that slot for winding a, d, g and j and dead slot part a ', d ', g ' and j ' differ (1 pole span)/24 mutually, the phase range of slot for winding a, d, g and j is less than (1 pole span)/3.Similarly, twining slot for winding c, f, i and the l of winding group B winding coil B1, B2, B3 and B4 and dead slot part c ', f ', i ' and l ' phase difference setting with same (1 pole span)/24.The phase range of slot for winding c, f, i and l is less than (1 pole span)/3.Similarly, twining slot for winding b, e, h and the k of winding coil C1, C2, C3 and C4 of winding group C and dead slot part b ', e ', h ' and k ' phase difference setting with same (1 pole span)/24.The phase range of slot for winding b, e, h and k is less than (1 pole span)/3.Further, the phase difference between the slot for winding group (b, e, h, k) of the slot for winding group (c, f, i, l) of the slot for winding group (a, d, g, j) of winding group A, winding group B and winding group C equals (1 pole span)/3 just.Because this result, the phase difference between three phase winding group A, B and C equals the 120el degree just, uses the distributor 30 among Fig. 8 can be changeed distance stably.
The whole phase place of slot for winding a to l and dead slot part a ' to l ' differs (1 pole span)/24 mutually, and people wish that the synthesizing magnetic with 1 pole span cycle diminishes.Figure 23 represents that the synthesizing magnetic of the waveform that changes to the magnetic of the slot for winding of l and the part of the dead slot from a ' to l ' with a and armature core 54 changes the waveform of TV.The magnetic of each slot for winding and dead slot part changes with respect to each A/F smooth change, each dead slot part a ', b ', c ', d ', e ', f ', g ', h ', i ', j ', k ' and l ' have with each a to the identical magnetic action of the slot for winding of l.Because the phasic difference mutually (1 pole span)/24 of slot for winding and dead slot part becomes very little so composite magnetic changes TV.The synthesizing magnetic that synthesizing magnetic among Figure 23 is changed TV and Figure 18 changes TV relatively, and the TV of electric rotating machine of the present invention is little more a lot of than the TV ' of common electric machine.Therefore, the embodiment of brshless DC motor of the present invention shown in Figure 20 has very little slot effect to change distance.
In the described embodiment of Figure 20, each tooth is free slot part, but the structure with the electric rotating machine of the present invention that reduces cogging torque is not limited in a kind of situation.In general, the electric rotating machine with cylindrical shape excitation permanent magnet assembly and armature core of magnetic materials can reduce cogging torque, and described magnet assemblies has around the rotating shaft of motor and is arranged alternately and by the N of permanent magnetization and the S utmost point.The quantity of the N and the S utmost point is P, it is an even number, described armature core has many teeth that form between two adjacent slot for windings, in slot for winding, twining the overlapping winding coil of many groups of polyphase windings, the quantity of tooth is T, it is not less than 2P, the number of phases of described many group polyphase windings is H, it is not less than 2, here, at least one of them described tooth has an extremely relative dead slot part with described permanent magnet at least, many tooth sections are arranged between two adjacent two slot for windings and the dead slot part, the tooth hop count is Tt, it is greater than T, described armature core has at least a pair of short element and long unit and they to be arranged alternately around rotating shaft, each described short element has a short tooth section at least, at least one full-height tooth section and not long tooth section, each described long unit has a long tooth section at least, at least one full-height tooth section and short tooth section, the effective pitch of full-height tooth section described here equals D=(360/Tt) degree, the effective pitch of each described short tooth section is less than D, and the effective pitch of each described long tooth section is greater than D.
The whole effective pitch of a pair of adjacent described short element and long unit equals or approaching to equal (360/P) Q degree be preferable, here, Q is one and is not less than 2 integer, the effective pitch of the short tooth section of each in described a pair of adjacent short element and long unit equals or the approaching D(1-J/Q that equals) degree, the effective pitch of each the long tooth section in described a pair of adjacent short element and long unit equals or the approaching D(1+G/Q that equals) degree, here J and G are not less than 1 and be not more than the integer of Q/2, preferably select J=G=1.Short tooth hop count in described short element preferably is not less than 2, and the long tooth hop count in the described long unit is not less than 2 simultaneously.Also can select short tooth hop count in the described short element to equal long tooth hop count in the described long unit, this number preferably equals Q-1 less than Q.Also can select each described long tooth section adjacent in both sides with two described full-height tooth sections, each described short tooth section is adjacent in both sides with two described full-height tooth sections.
Figure 24 (a) has represented to have other structure of the electric rotating machine of the present invention that reduces slot effect commentaries on classics distance to Figure 24 (d).The slot for winding of armature core 54 shown in Figure 24 (a) expression Figure 20 and Figure 21 from a to l and other arrangement mode of the part of the dead slot from a ' to l ', long tooth section, the position of short tooth section and full-height tooth section is different from the armature core 54 among Figure 21.Be that tooth section c-c ', c '-d and d-d ' are long tooth sections, tooth section g-g ', i '-j and l-l ' are short tooth sections, and other tooth section is the full-height tooth section.Armature core only has a pair of long unit and short element, for example, and long unit＜a, f〉and short element＜f, a.The effective pitch of long tooth section equals D(1+1/P)=18.75 degree, the effective pitch of short tooth section equals D(1-1/P)=11.25 degree.So, Q=P=4, G=1, J=1.
Armature core 54 shown in Figure 24 (b) expression Figure 20 and Figure 21 other arrangement mode from slot for winding a to l and dead slot part a ' to l ', long tooth section, the position of lacking tooth section and full-height tooth section is different from the armature core 54 among Figure 21.Be that tooth section a '-b, b-b ' and d '-e are long tooth sections.Tooth section g '-h, h-h ' and j '-k are short tooth sections, and other tooth section is the full-height tooth section.Armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a.The effective pitch of long tooth section equals D(1+1/P)=effective pitches of 18.75 degree, short tooth section equal D(1-1/P)=11.5 degree.So, Q=P=4, G=1, J=1.
The slot for winding a to l of the armature core 54 shown in Figure 24 (c) expression Figure 20 and Figure 21 and dead slot part a ' arrive other arrangement mode of l ', long tooth section, and the position of short tooth section and full-height tooth section is different from the armature core 54 among Figure 21.Be that tooth section c '-d and f '-g are long tooth sections, tooth section i '-j and l '-a are short tooth sections, and other tooth section is the full-height tooth section.Armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a.The effective pitch of long tooth section C '-d equals D(1+2/P)=22.5 degree, the effective pitch of long tooth section f '-g equals D(1+1/P)=18.75 degree, the effective pitch of short tooth section i '-j equals D(1-2/P)=7.5 degree, the effective pitch D(1-1/P of short tooth section l '-a)=11.25 degree.So, Q=P=4, G=1 or 2 and J=1 or 2.
The slot for winding a of the armature core 54 shown in Figure 24 (d) expression Figure 20 and 21 arrives another arrangement mode of l ' to l and dead slot part a ', long tooth section, the position of short tooth section and full-height tooth section is different from the armature core 54 among Figure 21, be that tooth section C '-d and d '-e are long tooth sections, tooth section g '-h, i '-j and l '-a are short tooth sections, other tooth section is the full-height tooth section, armature core only has a pair of long unit and short element, for example, and long unit＜a, g〉and short element＜g, a.The effective pitch of long tooth section c '-d equals D(1+2/P)=22.5 degree, the effective pitch of long tooth section d '-e equals D(1+1/P)=18.75 degree, short tooth section g '-h, the effective pitch of i '-j and l '-a equals D(l-1/P)=11.25 degree.So, Q=P=4, G=1 or 2 and J=1.
As shown in Figure 24 (d), long tooth hop count is not equal to short tooth hop count.In general, electric rotating machine with columnar excitation permanent magnet assembly and armature core of magnetic materials can reduce slot effect is changeed distance, described magnet assemblies has permanent magnetization and the N and the S utmost point that be arranged alternately around machine shaft, the number of poles of these N and the S utmost point is even number P, described armature core has many teeth of making between two adjacent slot for windings, in these grooves, twining the overlapping winding coil of many groups of polyphase windings, the quantity of described tooth is several T that are not less than 2P, the number of phases of described polyphase windings group is one and is not less than several H of 2, here one of them described tooth has a dead slot part relative with the magnetic pole of described magnet assemblies at least at least, many tooth sections are arranged between two adjacent described slot for windings and the described dead slot part, described tooth hop count is the several Tt greater than T, therefore the angle setting of described slot for winding and described dead slot part not to wait have the described slot for winding in l pole span cycle of described magnet assemblies and the described dead slot number of phases partly greater than 2H(Tt/T).
Slot for winding and dead slot all phase places partly with l pole span cycle of described magnet assemblies preferably differ an identical angle (1 pole span)/Tt each other.
Claims (2)
1, electric rotating machine, it comprises cylindrical permanent magnet assembly (23; 43) reach the armature core of making by magnetic material (24; 44) described permanent magnet assembly (23; 43) have the permanent magnet poles N and the S utmost point that alternately is disposed at around the described electric rotating machine rotating shaft, and its number of poles P is an even number; Described armature core (24; 44) have many a plurality of slot for windings (25 that are made in; Tooth (26 between two adjacent slots 45); 46), and the polyphase windings group (A, B, many overlapping winding coil C) (A1, A2, A3, A4, B1, B2, B3, B4, C1, C2, C3, C4) in slot for winding, described tooth (26; 46) number of teeth T is the integral multiple that is not less than the P of 2P, and (A, B, number of phases H C) are not less than 2 to described polyphase windings group, described electric rotating machine is characterised in that described armature core (24; 44) at least one short tooth (n-o, q-r are arranged; I-j, k-l) at least one long tooth (b-c, e-f; C-d is e-f) with at least two full-height tooths (c-d, o-p; D-e j-k), thereby forms alternate configurations at least one short element ((m-a) of described rotating shaft; (g-a)) and at least one long unit ((a, m); (a, g)), wherein said at least one short element ((m, a); Each of (g, a)) has at least one described short tooth (n-o, q-r; I-j, k-l), at least one described full-height tooth (o-p; J-k) there is not described long tooth, described at least one long unit ((a, m); Each of (a, g)) has at least one described long tooth (b-c, e-f; C-d, e-f), at least one described full-height tooth (c-d; D-e) there is not described short tooth, and described full-height tooth (c-d, o-p; D-e, j-k) each has and is defined as adjacent two described slot for windings (25; 45) effective pitch of angle between the opening portion center of formation tooth, this pitch equals the D=360/T degree, described short tooth (n-o, q-r; I-j, the effective pitch of k-l) each is less than D, described long tooth (b-c, e-f; C-d, the effective pitch of e-f) each is greater than D.
2, electric rotating machine as claimed in claim 1 is characterized in that: described each short tooth (n-0, q-r; I-j, effective pitch k-1) equals D(1-J/Q) degree, described each long tooth (b-c, e-f; C-d, effective pitch e-f) equals D(1+G/Q) degree, wherein Q is not less than an integer of 2, and J and G are the positive integers that is not more than Q/2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85105975 CN1008419B (en) | 1985-08-06 | 1985-08-06 | Reduce the electric rotating machine of cogging torque |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 85105975 CN1008419B (en) | 1985-08-06 | 1985-08-06 | Reduce the electric rotating machine of cogging torque |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN85105975A CN85105975A (en) | 1987-02-25 |
| CN1008419B true CN1008419B (en) | 1990-06-13 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 85105975 Expired CN1008419B (en) | 1985-08-06 | 1985-08-06 | Reduce the electric rotating machine of cogging torque |
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| Country | Link |
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| CN (1) | CN1008419B (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101741195B (en) * | 2009-12-24 | 2012-06-27 | 哈尔滨工业大学 | Permanent magnet synchronous motor with interphase uncoupled structure |
| DE102010001619A1 (en) * | 2010-02-05 | 2011-08-11 | Siemens Aktiengesellschaft, 80333 | Stand of a permanent magnet rotating electrical machine |
| CN109936266B (en) * | 2017-12-15 | 2022-07-22 | Tvs电机股份有限公司 | Motor for vehicle |
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1985
- 1985-08-06 CN CN 85105975 patent/CN1008419B/en not_active Expired
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| CN85105975A (en) | 1987-02-25 |
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