WO2011143683A1

WO2011143683A1 - Electric machine and method for reducing a cogging torque of an electric machine

Info

Publication number: WO2011143683A1
Application number: PCT/AT2011/000233
Authority: WO
Inventors: Gerd Bramerdorfer; Wolfgang Amrhein
Original assignee: Austrian Center Of Competence In Mechatronics Gmbh
Priority date: 2010-05-20
Filing date: 2011-05-20
Publication date: 2011-11-24
Also published as: AT509968A1; AT509968B1; EP2572443A1

Abstract

The invention relates to a method for reducing a cogging torque of an electric machine, in particular a synchronous machine, comprising a rotor/actuator (2), a stator (4) spaced from the rotor/actuator (2) by a gap (3), at least one armature winding (6, 6', 6'') provided on the stator (4) and/or on the rotor/actuator (2), and an exciter part, which is provided on the stator (3) and/or on the rotor/actuator (2) and which produces an exciter field (13) having a fundamental wave in the gap. In order to create advantageous method conditions in order to reduce the cogging torque, a selection of at least one harmonic wave (14) from the harmonic waves (14) related to the fundamental wave (15) is made for the exciter field (13) in order to reduce the cogging torque. The at least one harmonic wave selected, when superposed with the fundamental wave (15), leads to an at least partial reduction of the cogging torque, and the selected wave (14) or selected waves is or are superposed with the fundamental wave (15).

Description

Electric machine and method for reducing a cogging torque of an electrical machine

Technical area

The invention relates to a method for reducing a cogging torque of an electric machine, in particular a synchronous machine, with a rotor / actuator, with a spaced by a gap to the rotor / actuator stator, with at least one provided on the stator and / or rotor / actuator armature winding and with an exciter part provided on the stator and / or on the rotor / actuator, which generates in the gap an excitation field, comprising a fundamental wave.

State of the art

To reduce unwanted forces in synchronous machines, which can lead to strong torque fluctuations especially at low speeds, as well as at rest and in the starting range as cogging torque, a variety of measures are known in which always a reduction of the average drive torque must be taken into account. Thus, inter alia, it is proposed to make the grooves on the stator oblique or offset (DE 196652796A1), to arrange the permanent magnets for the exciter field irregularly (DE433723A1), as well as to provide flattening on the rotor in the area of the embedded magnets (JP2000152534A) in order to increase the air gap there , Such measures are known not only in synchronous machines with rotors, but also in other electrical machines, in particular linear actuators with actuators. Especially with flattening and the associated magnification tion of the air gap but it comes to weakening of the excitation field, which can cause differently from rectangular exciter field progressions in a negative way reduced drive torque.

Presentation of the invention

The invention is therefore based on the object, starting from the above-described prior art, to provide a method in which a nutritive paste can be reduced without weakening the mean torque of the motor. In addition, the process should be quick and easy to use.

The invention achieves the stated object with regard to the method in that, to reduce the detent torque for the excitation field, a selection of at least one harmonic wave is taken from the harmonic waves related to the fundamental wave which, when superimposed with the fundamental wave, results in at least a partial reduction of the detent torque and the selected wave or waves are superimposed with the fundamental wave.

If a selection of at least one harmonic wave, from the harmonic waves related to the fundamental wave, is taken to reduce the cogging torque for the excitation field, which leads to an at least partial reduction of the cogging torque when superimposed with the fundamental wave, then a simple procedure rule can first be specified which can be acted upon by a cogging torque of an electric machine, without necessarily forcing a reduction in the mean drive torque of the motor must be taken into account when the selected wave or selected waves is superimposed or with the fundamental wave. For this purpose, it is only necessary to make such a selection from the harmonic wave or the harmonic waves, by means of which it is possible to reduce the proportion of the cogging torque attributable to the fundamental wave. Thus, this proportion component can be reduced, which can lead to a special reduction of the cogging torque or the total rest moment. For this, the harmonic niche or the modulation of individual harmonics have only a share component that coincides in frequency with the component component of the cogging torque of the fundamental wave, so that an existing antiphase can be used to reduce the component components of the cogging torque of the fundamental wave. In order to avoid that the harmonic or the harmonic wave or harmonic also has influence on the induced voltage, it is further proposed that the topology of the synchronous machine must satisfy the condition that the largest common divisor of the number of slots (Ns ) and pole pair number (pz) is equal to the number of slots (Ns) by m (gcd (Ns, pz) = Ns / m). It has been found that, when this condition and a concentrated winding design are fulfilled, an image of the fundamental-modulated harmonics in the induced voltage can be avoided if such a harmonic whose winding factor is negligibly small, in particular zero, is chosen. Needless to say, the field of excitation can be characterized by other waves, in particular by grooving effects, eccentricities, tolerances and so on. Decisive for the reduction of the cogging torque is that at least one superposition with at least one selected harmonic wave and the fundamental wave is performed.

Simplified process conditions can be further provided if the fundamental wave is superimposed with at least one selected harmonic wave, which harmonic waves generate a share component of the same-order cogging torque to the other nugget moment component component generated by the fundamental wave. Existence harmonics with the same order and / or substantially opposite phase in their share component to share component of the fundamental wave, which may be the case for example due to the motor topology, so can be taken without special modulation measures on the cogging torque by this wave for superimposition with the Fundamental wave is used. On the cogging torque can be further influenced when the fundamental wave is superimposed with at least one selected harmonic wave, wherein at least one superimposition of fundamental wave and selected harmonic wave or harmonic waves generates a component component of the same moment Nutrastmoments to the other component component generated by the fundamental wave. Namely, it is possible for each magnetic wave to form a cogging moment as well as the superposition of different magnetic waves.

The table above shows an example in which the fundamental forms a nugget moment of order ni. By adding a suitable harmonic of the harmonics related to the fundamental wave, it is also possible to form a cogging moment of order Π3 by superposing the fundamental and harmonic waves. It can now be achieved by suitable selection of harmonic wave (s) that at least a superposition of harmonic and fundamental wave produces a nutrient component which has the same order as the component of the component produced by the fundamental wave alone. This means for the example that ni = n ₃ . If the phase relationship of the two component components is substantially opposite, this can lead to a reduction in the indexing moment.

In order to enable a particular reduction of the cogging torque, it is proposed that the amplitude and / or the phase angle of the fundamental wave and at least one selected harmonic wave or the selected harmonic waves are adjusted to one another. Preferably, the amplitude of the harmonics with respect to the amplitude of the fundamental wave is set or the amplitude of the harmonics is chosen such that thus reduces the cogging torque. In addition, this adjustment can be used to easily influence an achievable mean moment of the synchronous machine, in order to avoid a reduction, for example. In addition, the phase Shift the proportion component of the Nutrastmoments the selected harmonics to the phase of the proportion component of the Nutrastmoments the fundamental wave, for example, to a value between 90 ° and 270 °, preferably set to 180 °.

If at least one wave of the selected waves has a smaller winding factor than the fundamental, an influence of the superposition of harmonic and fundamental on the induced voltage can be kept small. In particular, so that particularly smooth-running electrical machines can be created when the winding factor is less than or equal to 0.25, preferably 0 ,.

In order to be able to exert particular influence on the mean moment of the synchronous machine, it is proposed that the superposition of the fundamental wave with at least one wave of the selected harmonic waves generates an exciter field with an amplitude smaller than or equal to the amplitude of the fundamental wave. In contrast to the prior art, even with a reduced cogging torque, a constant mean moment can be achieved - sometimes even an increased moment. Namely, known from the prior art losses can be compensated in a simple manner by increased parameters on the exciter field, which despite the reduced state of the art, can ensure unchanged high average moments despite a reduced cogging.

In particular, it has proved to be advantageous if the fundamental wave is superimposed with at least one harmonic wave of odd atomic number, in particular of the third order harmonic wave. In particular, it has surprisingly been found that it is precisely the third harmonic wave that can be used ideally for reducing the cogging torque, because this harmonic often produces a share component of the same order compared to the component component of the fundamental wave on the cogging key, but often also has no influence on the induced voltage showed the machine, and therefore need not be considered in the calculation of the synchronous machine. Has at least one selected harmonic wave (14) in the tolerance range of +/- a quarter period relative to the respective harmonic wave (14) relative to the zero crossing of the fundamental wave (15) at least one adjacent zero crossing (34), in particular at least one selected harmonic wave at least one with the fundamental shaft (15) common zero crossing (34), on, then the cogging torque components can be used improved to allow a particularly reduced total rest torque.

Simplified process conditions may continue to result if the amplitude of the fundamental is set equal to or less than 127% of the amplitude of the exciter field. This range limit could be confirmed by experiments in that at higher amplitude values an adverse effect on the rotational behavior of the rotor of the electric machine was established. Based on the upper limit of 127% is thus given a simple procedural rule by which a cogging of an electrical machine, in particular synchronous machine, can be reduced.

In a simple way, the superimposition of the fundamental wave and selected harmonic Weller at least over a section with the help of the course of at least one of the mutually facing stator and rotor / Aktorg renzflächen be formed. For example, in rotors with surface-mounted magnets, the interface of the permanent magnets can be designed according to the desired field excitation. In the case of rotors with embedded magnets, for example, the boundary surface facing the stator can be formed in accordance with the desired exciting field profile.

However, such a field of excitation can also be generated by this by means of a local distribution and / or the local course of the magnetization direction and / or the local course of the magnetization of permanent magnetic materials is formed. For example, permanent magnets can be used for this purpose and, with their local distribution or their locally different magnetization, the excitation field can be designed accordingly. The invention has also set itself the task of an electric machine of the type described in such a constructive way to change that despite a high average torque is expected only with low cusps, in particular a cogging can be extinguished.

The invention solves the stated object with regard to the device in that the construction of the rotor / actuator and / or stator corresponding to generation of an exciting field comprising superimposing the fundamental wave with at least one harmonic wave selected from the harmonic waves related to the fundamental wave when superimposed with the fundamental wave leads to an at least partial reduction of the cogging torque is formed.

Is the construction of the rotor / actuator and / or stator according to generation of an exciting field, comprising a superimposition of the fundamental wave with at least one selected from the harmonic waves related to the fundamental wave harmonic wave when superimposed with the fundamental wave to an at least partial reduction of the cogging torque leads, trained, then a particularly smooth running electrical machine can be created. The cogging torque of such a machine can namely be comparatively low, without having to expect such a construction with a reduction of the average torque of the machine. This also allows a cost-effectively manufactured and stable machine can be created.

Does the exciter field a dependence on a structural design of at least one interface, in particular of gap-side permanent magnetic and / or ferromag netic materials on, then can be easily created a construction for the formation of a field exciter. Such interfaces can form, for example, between air and material or even between the successive materials. In a structurally simple way, an excitation field can be created, which has a dependence on at least one local distribution of at least one material and / or at least one local distribution of at least one material property.

The construction can be further simplified if the local distribution of the magnetic material properties has a homogenous or at least partially distributed magnetization in the direction and / or amplitude, at least in some areas. Thus, namely, a field of excitation can be generated in a simple manner, on the basis of which a reduced cogging torque can be expected.

Such a reduction can also be made possible in a structurally simple manner in that the rotor / actuator and / or stator has at least one saturation zone, in particular in the form of saturation webs, for example in the case of embedded permanent magnets.

Is the amplitude of at least one of the selected harmonic waves equal to the magnitude with a potential variation of up to +25 to -25 percent, preferably up to +10 to -10 percent, of the maximum amplitude of the excitation field by which the amplitude of the fundamental is maximum amplitude of the exciter field is increased, then can be expected with a reduced cogging torque. Because of this, the component components of the shafts can advantageously be compensated for at the cogging torque.

If, at a substantially radial exit of the air gap field, in particular in the case of ferromagnetic pole shoe design and / or permanent magnet pole shoe design, the height H (phi) of the pole formation essentially follows the progression of the amplitude of the excitation field, then in a simple manner a cogging in such electrical machines can be reduced become. In general, it is mentioned that in electric machines, the course of the contour of the interface can be set in a wide range by a formula H (phi) by the formula:

H (phi) = c (phi) + p * [a _{ * sin (phi + alpha,) + ^ {a _n * sin (n * (phi + alpha _n ))}]

"

c (phi) offset;

p is a proportionality factor by which the term in the rectangular

Clamp is normalized to a maximum value of 1;

ai is the amplitude of the fundamental wave;

a _{n is} the amplitude of the selected n th harmonic;

alphai the displacement angle of the fundamental wave;

alpha _{n is} the shift angle of the selected n-th harmonic;

phi of the electrical angle;

In particular, upon selection of the third harmonic a1 and a3, it can be set so that a1 is increased by an amount x compared to the value 1 and a3 has the value of x. Advantageously, this amount x less than or equal to 0.47 can be selected. Furthermore, simplified process conditions can be created by making the offset c (phi) angle independent, especially when the offset c (phi) is zeroed, for example, with permanent magnets.

In contrast, in the case where the air gap field does not substantially exit radially, in particular in the case of permanent-magnet pole shoe design with substantially non-radial magnetization, the height H (phi) of the pole formation can be substantially proportional to the variation of the angle-dependent amplitude of the exciter field with an angle-dependent one Follow course correction, which also so that in a simple way a Nutrasten can be reduced. A course correction can be achieved, for example, constructively, by the course of the contour of the boundary surface, which can be usually described by H (phi) at substantially radial exit of the magnetic field from the interfaces facing each other, by L (phi) can be expressed: L (phi) = H (phi) / correction (phimech);

Phimech represents the mechanical angle, this is to set for the design of each pole piece always for the Polmitte to 0;

Correction (phimech) = 1 / cos (phimech);

In order to take into account a tolerance band, it is proposed that the angle-dependent contour K (phi) of the pole formation of the height H (phi) or the height H (phi) with angle-dependent course correction with a fluctuation range of up to +25 to -25 percent, preferably from up to +10 to -10 percent, based on the maximum value of height H (phi) or height H (phi) with angle-dependent slope correction.

In general, it is further mentioned that in machines, the periodicity of the nutritive torque with respect to the power transmission movement caused by any single harmonic wave from the harmonic waves related to the fundamental wave can be calculated by the following formula:

Where n _c denotes the periodicity of the Nutrastens related to the periodicity of the fundamental wave, both periodicities related to the power transmission useful movement,

N _{s is} the number of stator slots,

p _{z is} the pole pair number of the exciter part and

n _{m is} the periodicity of the considered harmonic wave related to the periodicity of the course of the fundamental wave. For example, for the consideration of the fundamental wave n _{m would be} equal to 1 and for the consideration of the third harmonic related to the fundamental wave n _m equal to 3.

The result for different numbers of stator slots N _s and pole pair numbers p _{2 are the} following periodicities of the cogging torque:

The above table serves as an example of selected waves of the magnetic field of selected groove / pole pair number combinations. This table does not include the previously mentioned superpositions of waves with different atomic numbers.

Short description of the drawing

In the figures, the subject invention is illustrated by way of example by way of example. Show it

1 is a sectional view of a synchronous machine according to the prior art,

2 is an enlarged detail of the sectional view of FIG. 1,

3 is a sectional view of a synchronous machine according to the invention,

4 is an enlarged detail of the sectional view of FIG. 3,

5a and 5b is a representation of the course of exciter fields, 6 shows torque profiles of the synchronous machines according to FIGS. 1 and 3, FIGS. 7a, 7b and 7c show an enlarged sectional view of a further embodiment of the invention with reduced cogging torque,

8 shows an alternative embodiment of a tooth of the stator according to FIG. 1,

FIGS. 9 and 10 show different magnetizations of permanent magnets; and FIG. 11 shows a representation of a pole formation H (phi) having a fluctuation width.

Ways to carry out the invention

1 shows a sectional view of a known from the prior art and only partially shown synchronous machine 1, which has a rotor 2 and a spaced by a gap 3 and 3 air gap stator 4. AC-conducting windings 6, 6 ', 6 ", etc. are provided as armature windings in the slots 5 of the stator 4, which generate a rotating field (not shown) .The rotor 2 has permanent magnets 8, which are provided embedded in the rotor 2. 2, a radially extending air gap 3 with a constant width is provided between the rotor 2 and the stator 4, only in the area of the grooves 5 there are changes in the width of the air gap 3 through the grooves 5. The embedded permanent magnets 8 are designed to generate an idealized rectangular excitation field 9 as shown in Fig. 5a In the Fourier decomposition, this exciter field 9 has a fundamental wave 10 and a plurality of harmonic waves 11, 12, etc., of which only the third one is for simplicity Harmonic 11 and the fifth harmonic 12 has been shown. Other exciter fields 9 are conceivable, for example wise sinusoidally extending, as is often proposed to reduce the cogging torque. However, rectangular exciter fields 9 have the advantage over other exciter fields of being able to produce a high average torque, so that they are frequently taken into account in the design of the motor topology of synchronous machines 1. Considering now fundamental wave 10 and the harmonics 11, 12 with regard to their influences on the cogging torque, it can be seen that each of these waves 10, 11, 12 to a proportion of component on the entire cogging torque leads, whereby these proportions components are also characterized by the engine topology.

According to the invention, it is now proposed to reduce the cogging torque by paying special attention to these component parts 11, 12, etc. Thus, the superposition of fundamental wave 10 and at least one harmonic wave 11 is used to reduce the cogging torque, although just in the prior art this known superposition can lead to increased cogging torque. For it was possible to obtain the knowledge that a selection of a harmonic or harmonic influence on the cogging torque can be used. Thus, it can be seen from FIG. 5b that the field of excitation 13 is shaped differently with respect to the rectangular exciter field 9 according to FIG. 5b. Namely, the exciting field 13 is created by a superposition of a harmonic wave 14 and its fundamental wave 15. This superimposition (modulation) leads to an exciting field 13, which is smaller in area than the excitation field 9 according to FIG. 5 a, but in contrast to this excitation field 9 has a special influence on the detent torque, as shown in FIG can be. In this Fig. 6, the normalized torque curves 16 and 17 are shown, which may arise on the basis of the two exciter fields 9 and 13. Thus, a harmonic wave can be seen clearly in the course of moments 16, which forms relative to the reference line 18. According to the invention, an extinction of this harmonic wave could be created in the course of the torque 17, so that a torque curve 17 is established essentially without torque fluctuations due to a cogging torque.

The exciting field 13 according to the invention can be formed, for example, by a flattening 19 on the rotor 20 of the synchronous machine 21, as has been shown in FIGS. 3 and 4 and thus differs from the synchronous machine shown in FIGS. 1 and 2. Although this flattening 19 increases the air gap 3 between the rotor 20 and stator 4, but as shown in Fig. 6 has no effect on the mean moment of the machine - on the contrary, by the inventive superposition of fundamental 15 and harmonics 14 is the even improved mean torque, which can be detected on the basis of the torque curve 16 increased torque curve 17 of FIG. 6.

Advantageously, the fundamental wave is superimposed with at least one harmonic wave 14, which generates a component component of the nutritive moment with the same order for the proportion component of the nutritive moment generated by the fundamental wave. For this purpose, the third harmonic 14 has proven to be advantageous. Namely, the share component of the third harmonic nutation torque 14 is the same as the order of magnitude of the fundamental wave 15 for most motor topologies, so that simple process conditions can be provided.

According to FIGS. 5a and 5b, an increased suppression of the cogging torque can be detected, namely by adjusting the amplitude of the fundamental wave 15 and of the superimposed harmonic wave 14 relative to one another. In this case, the amplitude of the harmonic 14 of FIG. 5b is reduced compared to the amplitude of the harmonic 11 of FIG. 5a, which can be recognized by the reference numeral 22. Experiments showed that an increase of the fundamental 15 of up to 18% can be used as advantageous for reducing the cogging torque.

According to FIGS. 7a, 7b and 7c, for example, the method according to the invention for superimposing fundamental wave 15 and harmonic wave 14 using the profile of the stator-facing side of the rotor 2 and of the surface-mounted permanent magnets 8 ', 8 "and 8"' is explained.

First, based on the mechanical and structural requirements, the topology of the synchronous machine is determined, whereby, for example, adjoining permanent magnets 8 'are provided on the rotor 2, as shown in Fig. 7a. By the adjoining permanent magnet 8 ', a nearly rectangular exciter field 9 is to be generated for a comparatively high average torque. Such a field of excitation 9 became, for example already shown in Fig. 5a. Other pathogens are not excluded.

In the next step, the fundamental wave 10 is extracted from this exciter field 9, as shown in FIG. 5a.

For illustration, an embodiment for generating a fundamental wave 10 is shown in FIG. 7b. For this purpose, the permanent magnet 8 ", which is radially magnetized over its magnetic area, are only changed in their course, as shown in Fig. 7b, and thus provided on the rotor 2. The original course of the permanent magnets 8 'was shown in Figs. 7b and 7c for better illustration entered.

However, this embodiment according to FIG. 7b itself, like the embodiment according to FIG. 7a, suffers from a comparatively high cogging torque.

In a further step, at least one harmonic 11, 12 of the excitation field 9 is now determined and checked for its suitability for reducing the cogging torque by superimposing it on the fundamental wave 10. If the component components of the harmonics 11 or 12 and of the fundamental 15 coincide at the cogging torque in such a way that an at least partially mutual cancellation can be utilized, then this harmonic 11 or 12 can be used to reduce the total rest moment.

The result of this superimposition of selected harmonic 1 and fundamental wave 10 can be recognized, for example, in FIG. 5 b. The fundamental wave 15 and selected harmonics 14 then lead to an exciting field 13. This exciting field 13 can be reproduced by the course of the permanent magnets 8 "', as shown in Fig. 7c Here is clearly an enlarged upper flattening 24 with respect to that shown in FIG 7b, or its flattening 24, which difference has been made clearer by reference numeral 25. This is a relatively easy manageable method for reducing a cogging torque created in synchronous machines.

According to FIG. 8, an alternative embodiment of a tooth 26 of the stator 4 according to FIGS. 1, 2, 3 and 4 is shown. The tooth 26 forms on its interface 27 a lip-shaped course, by means of which an excitation field 13, as shown for example in FIG. 5b, can be generated to reduce the cogging torque.

According to FIGS. 9 and 10, different magnetizations of permanent magnets 28 and 29 are shown. Thus, the permanent magnet 28 has a radial magnetization, whereby an air gap field 31 emerges substantially radially from the boundary surface 30. In order to generate the exciting field 13 here, the boundary surface 30 follows the contour of the superimposition of fundamental wave 15 and harmonic wave 14.

In contrast, a parallel magnetized permanent magnet 29 is shown in FIG. 10, whereby essentially an air gap field 33 emerges non-radially from the interface 32. In order to be able to generate special excitation field 13 in this case as well, a gradient correction must be taken into account for the contour of the superposition of fundamental wave 15 and harmonic wave 14 or the harmonic waves.

An advantageous reduction of the cogging torque can, as shown in Fig. 5b, are achieved when the harmonic wave 14 with the fundamental wave 15 has a common zero crossing 34, and at their inflection points 34 'has a maximum in the opposite direction.

Referring to FIG. 1, a representation of a pole width H (phi) having a fluctuation width 35 is shown. Thus, it is shown substantially in FIG. 11 that with a substantially radial exit of the air gap field 31 in the case of a permanent-magnet pole shoe design, the height H (phi) of the pole formation 30 essentially proportionally follows the course of the amplitude of the exciter field 13. It is also shown that the angle-dependent contour K (phi) of the pole formation 30 of the height H (phi) or the height H (phi) with angle-dependent course correction with a fluctuation width 35 of up to +25 to -25 percent, preferably up to + 10 to -10 percent, based on the maximum value of height H (phi) or height H (phi) with angle-dependent course correction, follows. Thus, dash-dotted lines with K (phi) show that the contour K (phi) deviates in the right-hand region H (phi), but within the fluctuation range 35.

In addition, according to FIG. 5b, the amplitude of at least one of the selected harmonic waves 14 corresponds to the amount x by which the amplitude 37 of the fundamental wave 15 is increased with respect to the maximum amplitude 36 of the excitation field 13. A fluctuation ^'38 is indicated here, being admitted to the amount x is a variation of 38 up to +25 to -25 percent, preferably up to +10 to -10 percent of the maximum amplitude 36 of the excitation field 13, which in Figure 5b only one-sided fluctuation width 38 has been indicated.

Claims

Patent claim:

1. A method for reducing a cogging torque of an electric machine, in particular a synchronous machine, with a rotor / actuator, with a spaced by a gap to the rotor / actuator stator, with at least one provided on the stator and / or on the rotor / actuator armature winding and with a exciter part provided on the stator and / or on the rotor / actuator, which generates in the gap an exciter field, comprising a fundamental wave, characterized in that for reducing the detent torque for the excitation field (13) a selection of at least one harmonic wave (14), of the to the fundamental wave (15) related harmonic waves (14), is taken, which leads to an at least partial reduction of the cogging torque when superimposed with the fundamental wave (15), and the selected wave

(14) or selected waves are superimposed on the fundamental wave (15).

2. The method according to claim 1, characterized in that the fundamental wave

(15) is superimposed with at least one selected harmonic wave (14), which harmonic wave (14) or harmonic waves (14) generates or generates a proportion component of the same-moment cogging torque to the other proportion component of the cogging moment produced by the fundamental wave (15) ,

3. The method of claim 1 or 2, characterized in that the fundamental wave (15) is superimposed with at least one selected harmonic wave (14), wherein at least one superposition of the fundamental wave (15) and selected harmonic wave (14) or harmonic waves (14) generates a share component of the same-order cogging moment to the other share component generated by the fundamental wave (15).

4. The method of claim 1, 2 or 3, characterized in that to reduce the cogging torque, the amplitude and / or the phase angle of the fundamental wave (15) and at least one selected harmonic wave (14) or the selected harmonic waves are adjusted to each other.

5. The method according to claim 1 to 4, characterized in that at least one wave (14) of the selected harmonic waves has a smaller winding factor than the fundamental wave (15), in particular a winding factor less than or equal to 0.25, preferably 0.

6. The method according to any one of claims 1 to 5, characterized in that the superposition of the fundamental wave (15) with at least one wave (14) of the selected harmonic waves an excitation field (13) having an amplitude equal to or less than the amplitude of the fundamental wave (15) generated.

7. The method according to any one of claims 1 to 6, characterized in that the fundamental wave (15) with at least one harmonic wave (14) odd order, in particular the harmonic wave (14) third order, superimposed.

8. The method of claim 1 to 7, characterized in that at least one selected harmonic wave (14) in the tolerance range of +/- a quarter period relative to the respective harmonic wave (14) relative to the zero crossing of the fundamental wave (15) at least one adjacent zero crossing (34), in particular at least one selected harmonic wave has at least one zero crossing (34) common to the fundamental wave (15).

9. The method according to any one of claims 1 to 8, characterized in that the amplitude of the fundamental wave (15) is set equal to less than 127% of the amplitude of the exciter field (13).

10. The method according to any one of claims 1 to 9, characterized in that the superimposition of the fundamental wave (15) with at least one selected harmonic wave (14) at least over a partial section with the help of the course of at least one of the facing stator and rotor / Actuator interfaces (27, 30, 32) is formed.

11. The method according to any one of claims 1 to 10, characterized in that the superposition of the fundamental wave (15) with at least one selected harmonic wave (14) by means of a local distribution and / or the local Course of the magnetization direction and / or the local course of the magnetization of permanent magnetic materials, in particular of permanent magnets (8) is formed.

12. Electrical machine, in particular synchronous machine, with a rotor / actuator, with a spaced by a gap to the rotor / actuator stator, with at least one provided on the stator and / or rotor / actuator armature winding and with a stator and / or rotor / actuator provided exciter part for generating a fundamental wave having excitation field in the gap, wherein the construction of the rotor / actuator and / or stator is designed such that there is a reduction of the cogging torque, characterized in that the construction of the rotor / actuator (2) and or stator (4) corresponding to generation of an exciting field (13), comprising a superposition of the fundamental wave (15) with at least one harmonic wave (14) selected from the harmonic waves related to the fundamental wave (15) Basic wave (15) leads to an at least partial reduction of the cogging torque is formed.

13. Electrical machine according to claim 12, characterized in that the excitation field (13) has a function of a structural design of at least one interface (27, 30, 32), in particular of the gap-side permanent magnetic and / or ferromagnetic materials.

14. Electrical machine according to claim 12 or 13, characterized in that the excitation field (3) has a dependence on at least one local distribution of at least one material and / or at least one local distribution of at least one material property.

15. Electrical machine according to claim 14, characterized in that the local distribution of the magnetic material properties has at least in some areas a homogeneous or in the direction and / or amplitude locally differently distributed magnetization.

16. Electrical machine according to claim 14 or 15, characterized in that the rotor / actuator (2) and / or stator (4) has at least one saturation zone, in particular in the form of saturation webs, for example in embedded permanent magnets (8).

17. Electrical machine according to one of claims 12 to 16, characterized in that the amplitude of at least one of the selected harmonic waves (14) the amount (x) with a possible fluctuation (38) of up to +25 to -25 percent, preferably of up to +10 to -10 percent, corresponds to the maximum amplitude (36) of the exciter field (13) by which the amplitude (37) of the fundamental wave (15) is increased from the maximum amplitude (37) of the exciter field (13).

18. Electrical machine according to one of claims 12 to 17, characterized in that at a substantially radial outlet of the air gap field (31), in particular in ferromagnetic poly pole design and / or permanent magnetic Polschuhgestaltung, the height H (phi) of Polausbildung (30) essentially proportionally follows the course of the amplitude of the exciter field (13).

19. Electrical machine according to one of claims 12 to 8, characterized in that at a substantially non-radial outlet of the air gap field (31), in particular in permanent magnet pole shoe design with substantially non-radial magnetization, the height H (phi) of Polausbildung (32 ) substantially proportionally follows the course of the angle-dependent amplitude of the excitation field (13) with an angle-dependent course correction.

20. Electrical machine according to one of claims 12 to 19, characterized in that the angle-dependent contour K (phi) of the Polausbildung the height H (phi) or the height H (phi) with angle-dependent course correction with a fluctuation range (35) of up to +25 to -25 percent, preferably up to +10 to -10 percent, based on the maximum value of height H (phi) or height H (phi) with angle-dependent slope correction.