DE3401163A1 - Electrical machines having permanent-magnet excitation, and as a reluctance version in a laminated excitation arrangement - Google Patents

Abstract

In order to achieve high force intensities with a favourable efficiency, a high magnetic-field intensity in the air gap has major significance. As a result of the so-called collector arrangement, relatively high air gap inductions can be achieved, with limited use of material for the permanent magnets. In order to reduce the relatively high armature reaction and the scatter, longitudinal lamination and a triangular shape of the soft-iron poles (Figure 4) are proposed. This results in an increased force intensity, a lower apparent power, less scatter and negligibly small surface losses. Furthermore, the possibility is provided for leakage-flux control, by means of which the air gap induction can be influenced. If the partial poles are magnetically conductively connected and permanent magnets are dispensed with, a highly favourable rotor arrangement results for reluctance machines. The use of a multi-phase winding and the capability for armature-field compensation by means of permanent magnets are proposed. <IMAGE>

Description

"Electrical machines with permanent magnet excitation or

as a reluctance version in a laminated exciter arrangement Problem and Objective Show electrical machines with excitation by permanent magnets has advantages over electrically excited machines.

This is very easy to do, especially when feeding from an inverter Use built-up machines that have a small pole pitch and small iron masses can be designed.

Their efficiency is higher than that of electrically excited machines. Permanent magnets with high energy density (large product of flux density and field strength) prove to be superior to the less energetic magnets.

In particular, the advent of the rare earth cobalt magnets sparked one Discussion about the cheapest machine design, as this is compared to magnetic material the magnets used so far is much more expensive. It had been there for a long time known that permanent magnets not only in the form of direct assignment to the useful gap (Flat arrangement), but can also be used in the collector configuration can. The direct assignment to the useful gap (see Figure 1) means that the flux density of the magnet is approximately equal to that of the useful gap.

This applies at least as long as the useful gap in relation to the magnet height is small. The collector configuration (see Fig. 2) allows greater flux densities in the useful gap than in the magnet too. This is achieved by a large magnet arrangement; the The cross-sectional area of the magnet is larger than the pole area in the useful gap. Corresponding the flux density in the magnet is lower than that in the pole area. The now necessary In contrast to the arrangement shown in Figure 1, flux diversion requires special soft iron poles. Their weight can be greater than that of the yoke arrangement in Figure 1. Another The disadvantage of the collector arrangement is that, especially with larger useful gap lengths a not inconsiderable leakage flux on the side of the magnet facing away from the gap can be perceived. This cancels out some of the beneficial effects.

Figure 1 shows the permanent magnets directly assigned to the useful gap s 1, a stator 2 with current-carrying grooves 3, the Stator yoke 4 and the rotor yoke 5. The dot-dash line corresponds to the field generated by the magnets drawn field line b. The magnetic yoke 5 of the rotor is one-sided effective arrangement of the stator necessary; it can be in a double-sided arrangement is known to be avoided.

The magnet arrangement based on the collector principle (Fig. 2) is particularly suitable to achieve high flux densities in the air gap. In addition to the greater radial height of the Magnet arrangement arises the advantage of a more favorable utilization of the magnet material. For magnets with largely straight demagnetization characteristics (in the 2nd quadrant) a large magnet cross-section leads to a magnet utilization close to the energy maximum. This can be achieved at a flux density that is about half the remanent induction is equivalent to. With the same material expenditure for the magnets, higher flux densities can be achieved than with arrangements according to Fig. 1. The latter brings an increase in size the magnet height only a small increase in the flux density. Because the energy product decreases again with increasing height, the decreases above an optimal magnet height Utilization of the magnetic material.

With the arrangement according to Fig. 2, you can select the parameter magnet height and magnet cross-section, the magnet utilization can be kept at an optimum. Through this can be on the field paths b with a given material expenditure for the magnets in principle achieve higher flux densities.

For practical use, however, proves to be disadvantageous that Relatively large leakage flux components occur on the field trajectories c. this leads to to the fact that only part of the magnet cross-section for magnetizing the useful gap 6 is available.

A corresponding one is also created on the end face of the magnet arrangement Leakage flux. The magnitude of the leakage flux increases if the magnet height (in the direction of magnetization) decreases. Due to the stray flux components that become effective as the magnet height decreases the dimensioning advantages described are partially reduced.

Another major disadvantage for arrangements as shown in Figure 2 is in that the current of the armature winding causes a strong field distortion. at the flat arrangement (Fig. 1), on the other hand, is found to be advantageous in that flux densities only reach small values on field tracks of the form a.

This is a consequence of the fact that the magnetic material is suitable for External fields behave similarly to air. It can thus be stated that the The greater the height of the magnet, the less the armature reaction causes the field distortion is.

For machines with large armature currents, high magnets are beneficial, although they one with regard to the generation of a high field density of the excitation field represent an uneconomical solution. The practical application of magnetic circuit design according to Figure 2, however, is very hindered by the strong anchor reaction. So works it reduces itself to the achievable power density.

A large field distortion has for inverter-fed machines other disadvantages. The field component of the armature currents of the q-axis causes a large one Transverse stress component Xq Ia (dashed part in Figure 3). The corresponding stress component is plotted in the diagram perpendicular to the voltage vector Up) of the pole wheel voltage. The armature voltage amount Ua is correspondingly large compared to the voltage Up The voltage increase is the same for the dimensioning of the inverter with an increase in performance and thus the choice of larger components. The rotation too of the current vector against the voltage Up in the direction of the armature voltage Ua does not lead to a significantly more favorable solution to this problem.

The increased share of electricity that results in a lower degree of efficiency, thus worsens the energy use and shifts the dimensioning problem from the inverter to the winding. The transition to the magnet arrangement according to Fig 1 enables a slim stress diagram with a smaller stress component of the armature field and a correspondingly reduced armature voltage Ua (extended Part of the diagram) What is desired is an improved magnet arrangement, which combines the advantages of both concepts.

It is desirable to achieve higher flux densities than those shown in Figure 1 to be able to. However, it should not take into account the well-known disadvantage of the collector arrangement, consisting of high anchor reaction and high leakage flux.

We are looking for a configuration that makes the best possible use of the magnetic material together with the advantage of high magnetic resistance for excellent field paths, according to a and c. In addition, the goal is also calculated for some applications to carry to provide an adjustable flux density in the useful gap. With limited Additional effort is sought to ensure that the electrical or mechanical interventions Flux density can be influenced. The transition to one without permanent magnets designed machine with power allocation to a rotor with pronounced poles (Reluctance motor with current orientation) is within the scope of the improvements described here a corollary of the development.

The described improved excitation concepts can be used for arrangements in which the normal forces generated by the magnetic field also play a role, advantageous use. This particularly applies to the excitation systems that can be set in the field.

The collector arrangement with minimal armature feedback and low scatter The magnet arrangement according to Figure 1 leaves no satisfactory possibilities for one favorable use of the magnet material if high air gap flux densities are achieved should. A flux density of e.g. more than 0.6 T is particularly compelling even when used high quality rare earth cobalt magnets already at an oversized magnet height. The energy density is already beyond the optimal value.

For an improvement of the arrangement, therefore, the collector arrangement is required (Photo 2) to go out. To begin with, the disadvantage of the large anchor reaction on field railways to eliminate according to a, it must be remembered that the course of the field lines b must not be disturbed by increased magnetic resistance. It must be both for the parts of the magnet close to the air gap as well as those remote from the air gap high conductivity towards the air gap are ensured.

Conversely, for field lines of the form a, the one shown in Figure 2 must be used Be interrupted way over the soft iron of the pole.

A first step in increasing magnetic reluctance for field tracks a there is a gap in the middle of the pole.

This gap must extend over the entire height. To be effective to be, it should be larger than the air gap, especially if the pole flooding the armature winding is large. Should machines have a large pole pitch with a large current load it turns out that the division of the poles is only helpful to a limited extent is. Significant distortions continue to occur within the pole halves, so that large differences arise between maximum and minimum values of the flux densities. Taking into account the saturation, this means reducing the mean Flux density.

An effective measure to suppress even local field distortions especially with large pole pitches and at the same time a favorable arrangement in the With regard to the undisturbed field formation in the gap, there is a lamination of the poles according to Figure 4. The connection between the two in their direction of flow Permanent magnet 1 standing perpendicular to the gap and the useful gap S is over a soft iron pole arrangement 5 with non-magnetic spaces in between 6 reached. The gaps can be filled with solid material (e.g. plastic or non-magnetic metals). The proportion of non-magnetic filler material determines the residual magnetic conductivity effective across the lamellae. These is much lower than the conductivity longitudinal. The arrangement shown ensures that each tooth of the armature between the magnet is supplied with approximately the same flux density. In the entire pole area a constant induction Bb occurs, as shown in Figure 5. local fluctuations as a result of the drawn open grooves are not shown. About satiety influences to avoid, it must be assumed that the sum of the slat thicknesses is at least should correspond to the sum of the tooth thicknesses. As Fig. 4 shows, arises now for field lines of the form a an increased resistance, that several slots and the relatively large gap in the center of the pole must be bridged. In order to the flux portion to be assigned to the field line a for a given flooding becomes very high much smaller than in the case of Fig. 2. The flux density Bat which is the no-load field superimposed, turns out to be small even in comparison to the flat arrangement (Fig. 1).

The resulting field in the air gap gives way even with large armature currents only slightly depends on the shape of the idle field Bb.

It succeeds with the laminated arrangement of triangular partial poles A very extensive anchor field suppression without impairing the idle field to reach. The force density (force per unit area) reaches a greater ..

Value than with machines that are designed as shown in Figure 2.

As can be seen from the comparison of Figure 4 with Figure 2, this is a consequence the slits arranged between the lamellae also weaken the magnetic area Partial flows on field tracks of the form c (leakage flux component) given. Just a very small one Part of the permanent magnet is therefore used to generate the leakage flux; the far the largest part is reserved for the excitation of the useful flow.

The complete avoidance of stray fluxes according to the field line c, succeeds with double-sided symmetrical arrangements of the exciter part and stator. This double-sided arrangement can be relatively simple, e.g. in axial field machines be realized.

Basically it can be stated that the exciter arrangement described in collector form with laminated triangular poles for axial field and radial field arrangements is equally suitable. It is necessary in comparison to the flat arrangement of the magnets a larger rotor volume, but the magnets are more conveniently dimensioned, so that larger Flux densities can be achieved. The proportion of soft iron material corresponds to for example that of a slightly reinforced yoke arrangement as shown in Figure 1. It may, however it should be noted that the increase in rotor volume for most machines, especially those with a low speed and radial design hardly disadvantageous for the Carry comes. This is a space that is hardly for others anyway Tasks can be used.

It should also be pointed out that the magnetically poorly conductive The space between the slats is filled with mechanically very resistant material can be so that the lamellar association forms a solid unit. It can be thus also master high circumferential speeds. A fuse for the permanent magnets through a wedge-shaped closing element appears at high peripheral speeds expedient. The soft iron lamellas can be made of magnetically good conductive steel or make dynamo sheet from a few layers. To a minor impairment To achieve the air gap field Bb, a relatively fine subdivision is recommended. The slot width in relation to the air gap plays a role here. By the slots-related enlargement of the magnetically effective gap is usually by a corresponding enlargement factor for the air gap (Carter factor) expressed. To keep it close to 1, it is best to not adjust the slot width to be chosen much larger than the size of the air gap. Also the cheapest possible Use of the magnetic material speaks in favor of arranging a small lamella pitch. Larger slots cause a deformation or lengthening of the field lines within of the magnetic material, which means an increased magnetic resistance is.

The relatively fine lamination also proves to be beneficial with a view to suppressing eddy current losses that are close to the surface arise as a result of the field fluctuations caused by the slot openings. The usage of dynamo sheet for the lamellas results in a minimum of additional surface losses. They can be considered practically negligible in this case.

Because by the laminated triangular poles described the effectiveness the collector arrangement is improved, the technique described can also be used for more favorable Use of less energetic magnets can be used. It can be e.g.

the cheaper material of ferrite magnets with remanent induction by 0.38 T to generate a flux density of approx. 0.6 T. By now Largely suppressed armature reaction can be achieved by machines with relatively high Current layers can be designed with good efficiency.

For particularly high demands on power density and efficiency, let rare earth cobalt magnets with remanent induction of up to 1.1 T and approx use the same air gap induction. This value is significantly higher than that with the flat arrangement achievable; corresponding advantages in terms of dimensioning of the machine and its efficiency can be derived from it.

Apart from the machine design, there are also advantages for the Frequency converter. The inverter feeding the machine when it is driven can be low anchor reaction, i.e. small X according to Figure 3 (solid diagram) be designed with a relatively small apparent power. The product from maximum occurring voltage and maximum current corresponding power semiconductors are therefore more cost-effective than those of the machine types shown in Figure 2 and Figure 1.

The greatly reduced field deformation as a result of the armature currents is effective favorably on the commutation. It also has a beneficial influence to the maximum necessary clock frequency. In Figure 4, the armature winding is a multi-phase winding intended. With currents in phase, it leads to e.g.

six out of seven strands Su of a very high force density.

With an approximately rectangular magnetic flux density in the pole area According to Figure 5, the most favorable current distribution is to achieve high forces at maximum efficiency, it is assumed to be constant over the pole pitch as well Course of power distribution. As described elsewhere, you can get through the multi-phase concept also means higher component utilization for the inverter than about three-phase arrangements.

A particularly low-loss energy conversion and high component utilization A greater number of phases has been found to be achieved in the machine and inverter than 3 as particularly cheap. Furthermore, the phase numbers 5 and 7 allow e.g. due to a more favorable operating symmetry for the construction of the circuit for machine winding and inverters reduce the number of components required or provide a simpler solution than even phase numbers.

Becoming the reluctance machine with laminated rotor and current orientation the laminated triangular poles 5 there connected to one another in a magnetically conductive manner (7), where the permanent magnet was previously located, a magnetically passive one is created Rotor according to Figure 6. The width of the "gap" of the pole elements is determined by the number of armature coils (which are effective for exciting the magnetic field are the field density in the pole area. If a multi-phase winding is assumed again, in this way the coil currents which determine the field and the armature currents in the pole area can be determined separated to adjust. It is assumed that they are switched by switching operations can be influenced in the respective inverter phases. This method was called "current orientation".

The magnetic flux density, which corresponds to the field lines b1 and b2, is determined by the coil currents associated with the gap (e.g. two) of the flow rate G f caused. The magnetic field is practical due to the selected pole geometry again evenly distributed over the entire width of the pole. As with the excitement of the armature winding from the high conductivity of the main magnetic circuit including the small air gap is of particular importance, the Slots 6 between the slats and thus also the slat spacing kept small will. In order to achieve high mean force densities, the proportion of the pole gap is to limit at the pole pitch. It follows that the pole pitch of the reluctance machine is normally chosen larger than that of a permanently excited synchronous machine.

With electrical excitation from the armature, these Requirements also achieve high flux densities in the polar area. Through the laminated Pole arrangement can be the field deformation by the armature currents compared to other known Solutions are strongly pushed back. Picture shows the idle field Bb excited by the coils f and the resulting total a generated by the proportions of all coils 01 field.

The field distortion reduction in reluctance machines is from similar importance as in the case of permanent magnet synchronous machines. By smaller armature feedback allows higher force densities for a given current and higher component utilization in the inverter as well as more favorable commutation behavior achieve.

The inverter-fed reluctance machine achieves among those mentioned Requirements similarly high force densities as permanently excited machines. The elimination the permanent magnet means a cost saving and a simplification of the machine production. In addition, the adjustability of the excitation, as it is with multi-phase windings with independently fed strands, considerable operational Offers advantages. The setting and control behavior of a reluctance machine of this type resembles the behavior of a separately adjustable (separately excited) in the field and armature current DC machine.

For security-sensitive arrangements, the coil current De-excitation of the machine to be carried out can be a very positive feature. Leave it With the appropriate winding division, parts of the machine can also be found in the event of a malfunction switch off while undisturbed sectors remain in operation.

In particular by combining a laminated rotor with a The reluctance concept represents multi-phase winding and the corresponding inverter feed a solution that can be easily adapted to many applications. It corresponds to the desired one high quality of energy conversion (high efficiency) with favorable conditions for the control of almost any process with different requirements.

For applications with particularly high demands in terms of efficiency and power density of the machine, it is possible to further improve the reluctance concept to achieve that with the help of permanent magnets the armature field without power is compensated. Here, too, is to achieve a field equalization in the whole In the area of the pole, it is assumed that there are laminated pole elements as shown in the figure 6 exist. In this case, too, it is particularly advantageous to use the lamellae division to be smaller than the slot pitch of the stator. To compensate for the field railways a magnetic field generated by the currents of the armature are permanent magnets in the Laminated rotor slots applied. The direction of magnetization runs across the slots. It turns out that the use of ferrite magnets for Compensation of armature current coatings up to about 1200 A / cm is sufficient. By diminishing the slot width, the same material can be used to rectify the field even with smaller ones Make current coatings.

Relatively strong armature fields can thus be achieved with ferrite magnetic material be compensated.

Fig. 8 shows an arrangement that is very largely that of Fig 6 corresponds. Part 5 again denotes the soft iron lamellae. 6M stands for Permanent magnets inserted in the spaces that cover the entire space of the slots to complete.

Figure 9 shows the course of the flux density under load.

If the size of the currents in the coils is reduced, a field deformation occurs in the opposite direction compared to Figure 7. However, it can be assumed here be that with reduced circumferential force the disadvantages of field distortion no play a special role. The deformation now occurring in the opposite direction the field profile has the advantage, for example, that the commutation process is accelerated expires. The resulting field along the revolution a vanishes.

Field-adjustable machines with permanent excitation a) Combination of permanent excitation and armature excitation The upgrading of the collector configuration and described above the possibility of excitation via the armature with the help of a multi-phase arrangement can be combined. With these means it can be achieved that for one certain degree of excitation (a certain flux density of the no-load field) the excitation is generated exclusively without power by the permanent magnets, while higher or lower field densities are provided with the aid of armature excitation will. This corresponds to the sequence known for some applications, in which the operating states with maximum field and also those with minimum field only briefly in comparison to those with medium field density.

Figure 10 shows a suitably dimensioned magnet arrangement 1 with laminated Soft iron poles 5. The pole gap is similar to that of the reluctance version designed so wide that the necessary excitation flowOf to adjust the Idle field is available. Since the field density to be generated by the permanent magnet Bm is now lower than with exclusive permanent excitation (Fig. 4) reduce the height of the permanent magnet. For example, it can be used when using Rare earth cobalt magnets are still below 1 cm if Bm values between 0.4 and o.5 T should be achieved. Taking into account the area ratio of the magnet and a pole face of about 2, the magnet with a height of 0.8 means a fictitious one Air gap enlargement of about 0.2 cm. It is thus clear that with a limited Flooding @f Flux densities Bf from 0.2 to 0.3 T can be achieved, in picture 11 shows the course of the flux density for three cases.

Bm denotes the course of the field without armature excitation. Bm + Bf gives the achievable maximum value. The effects of the permanent magnets support each other here and that of the armature excitation. B - B m f denotes the minimum value of the flux density. The anchor excitation counteracts the permanent excitation. Depending on the magnet material care must be taken that the counter-excitation results in irreversible magnetization be avoided in the magnet material.

The setting of the flux density is within the described limits infinitely variable with the help of the armature currents.

The concept of mixer excitation is compared to other solutions particularly advantageous if the thickness of the permanent magnets is set low can be. This applies to high-quality magnetic materials such as rare earth cobalt magnets stronger than for example for ferrite magnets. Compared to a rigid permanent excitation considerable savings in magnet material can be achieved. In comparison the winding losses caused by the excitation currents add to the reluctance version back when the operating phases with low excitation predominate in terms of time. The for Field influence necessary current connection for the coils of the pole gap is with small time constant and thus feasible with little delay.

b) Mechanical changes in the magnetic circuit for a number A very rapid change in the magnetic field is not necessary for applications. It can then be assumed that e.g. a servomotor or a power amplifier is used with a buffer to move a mechanical part that in turn changes the conductivity of the magnetic circuit. The one from the permanent magnet The excited magnetic circuit in the rotor consists of the magnet itself and soft iron parts. In the case of an arrangement according to Figure 1 (flat magnet), mechanical intervention is required Changing the conductivity very difficult and hardly practicable.

The latter applies at least to rotating electrical machines.

For arrangements according to Fig. 2 or 4 there is the possibility to go through small modifications to the shape of the collector an adjustable magnetic bypass to carry out the useful gap.

As shown in Figure 12, in the magnet delimitation facing away from the air gap 6 a movable soft iron part K is used to influence the air gap flux density will.

In position A, the stray flux that forms at the end of the magnet is passed through the adjusting element K is practically not enlarged.

The maximum value of the flux density BA is found in the useful gap (Fig. 13) a. If K is brought into position B with the aid of a shifting device, it is enlarged the leakage flux (field line c) increases considerably. For example, between 3O and 4O% of the the flux generated by the magnet run via the byway c. The air gap field b is thereby weakened. This is shown in Figure 13 with a correspondingly smaller field density BB shown. By intermediate setting of K, intermediate values can be set continuously set the flux density within the limits BA and BB. The shift from K from position A requires greater mechanical forces. By a spring with corresponding characteristics or another storage element can be the forces be largely balanced in total; the drive K can focus on the application limit the small differential forces between the spring and magnet.

In the case of a rotating machine, the adjusting elements K can be used summarize a kind of cage. The movement of this cage in the circumferential direction can can be made by a common drive. As Figure 12 shows, there is there is still enough space for the attachment of the pole elements, even if for the Adjusting elements K the displacement is taken into account.

It is undoubtedly beneficial for the execution of the actuators and for the construction of the rotor 'that the adjusting movement in the circumferential direction is only about a quarter of the pole pitch includes. This is a result that the Use of the collector configuration is attributable.

For applications with magnetic bearings or with linear motors the normal force generated by the magnetic field and its adjustability of considerable additional Interest. The adjustability of the field in the useful gap can be used to control or Find regulation of normal force use. The control dynamics are increased Requirements. The normal force is used to compensate for the weight forces used. Since the mass fraction of the adjusting element K is small and the on K can compensate for the acting magnetic reaction forces very largely by a fast acting actuator (e.g. a hydraulic power booster) a very large acceleration can be achieved. Thanks to the limited shifting distance and the low net weight of K, short positioning times can also be achieved. The change in the magnetic field takes place between the limits BA and BB. The normal force is proportional to B² and changes accordingly. It thus appears very promising, as does the shifting of the adjusting elements K to regulate the gap with the help of normal forces. Compared to conventional Electromagnetic load capacity regulations occur in the case of the one described here Process the favorable dimensioning of the magnet and the low mass of the actuating elements and the resulting high adjusting dynamics are advantageous in appearance. To use in the case of magnetic bearings for rotating bodies, the Adjusting elements K in different sectors may be possible if bearing forces are in the both main directions are to be realized. With symmetrical Arrangement deflect the adjusting elements at different poles in opposite directions.

Figure 14 shows a modified positioning arrangement compared to Figure 12. The soft iron control element K is part of a cylinder and can be turned by rotating the Shaft W are brought into engagement with the magnet. For comparison to the arrangement according to picture 12 space is now saved in the circumferential direction. Furthermore A behavior similar to that described above for Figure 12 also applies to this arrangement.

The magnet arrangements described together with Figures 12 and 14 are not tied to a specific drive type with regard to the actuator. It However, there is also the option of using an electric drive (linear or rotating).

The lamellar shape of the pole elements can be modified so that a flux blockage over the entire height of the magnet can be achieved. Figure 15a shows one Arrangement in which two vertically displaceable elements parallel to the magnet 1 M are attached in the pitch of the slats. In position A the magnetic The flow is practically equally good in comparison with the arrangement in Fig. 4 (undivided lamellas) guided. In this position, the maximum flux density BA is reached in the gap (Picture 11). If, however, the slidable louvred grille M by half a division offset downwards, there are 5 flow restrictions at the transitions between M and the lamellae on. This results in the reduced flux density BB in the useful gap for position B. Depending on the shape of the individual elements, BB can also be set to even lower values adjust compared to BA. To move the elements M can again Use any type of actuator. The louvred grille M can also be one-sided carry out.

Figure 15b indicates that there is a possibility of the spaces M6 of the soft iron lamellas like the grooves of electrical machines with live To fill ladders. In doing so, the magnetic transition resistance can be reduced from the magnet to the actuator also a partially closed groove arrangement as in Figure 15c can be selected.

For the specified field and current direction, the result is the same as for a Linear actuator a downward acting actuator F.

It is the sum of the products of the current and the density of the magnetic Proportional to the field. When the direction of the current is reversed, the direction of the force be reversed.

It is assumed that the movement of the soft iron element caused reluctance force is compensated by a spring, then the one by the Current generated actuating force for the acceleration of the movable element M can be used to the full extent. It can be shown that favorable conditions exist in order to achieve high actuating accelerations and a rapid change in flux with a limited current to achieve in the useful gap.

As the sketches 15a to 15c show, an approximate turns out to be for M equal division of the space into soft iron lamella and groove as particularly favorable to achieve an effective flow shut-off. For linear motor arrangements appears further the connection of the conductors from the area of neighboring magnets to coils as a very cheap solution.

The adjusting devices described for influencing the magnetic Field in the useful gap can be operated as controls or regulators. In the event of the arrangement according to Fig. 15 is the current that is arranged in the actuating elements M. Head, controlled by an electric actuator and a controller.

The air gap can be calculated or measured in a known manner and compared with a target value. The difference in the air gap deviation and a gap change rate also determined are for the size based on the current modulation by the controller. Since the arrangement 1 5 except a very small adjustment deflection caused by a low mass, can achieve very high actuating speeds with limited actuating power. The levitation control can be implemented with little expenditure on electrical components. Under The flow blockage can be done without full symmetry with the help of the lamellar grille Also do M on only one side of the magnet.

Claims (11)

Protection claims 1. Electrical machines or magnetic support devices consisting of a fixed part (stator) and a moving part (rotor, Translator or exciter part), both of which are separated by an air gap (useful gap) within which a magnetic field is effective, indicated by that in the rotor or exciter part the magnetic field in a laminated soft iron pole arrangement, the Has non-magnetic gaps and their lamellae in the direction of the current-carrying Head of the stator run, is guided, with the soft iron lamellas either on both sides on the air gap (Fig. 6) or on the air gap and on permanent magnets (Picture 4). 2. Execution of the excitation part of an electrical machine according to claim 1, d a d u r c h, that the lamellar cross-section is roughly the same in total the corresponding tooth cross-sections, with a trapezoidal shape of the pole elements Enables sufficiently large spaces and thus an even distribution the no-load flux density across the pole width and in the presence of stator currents a low field distortion is achieved. 3. Execution of the excitation part of an electrical machine according to the above Claims, d a d u r c h, that for large anchor fluxes the The lamellar pitch is smaller than the slot pitch of the stator. 4. Execution of the excitation part of an electrical machine according to the above Claims, d a d u r c h, that for small anchor fluxes each Partial pole consists of only one lamella, a soft iron element in a triangular shape and a distance is maintained between the partial poles. 5. Electrical machine with laminated according to the above claims executed Excitation part, characterized in that the stator has a multi-phase winding a number of slots greater than 3 per pole pitch and assigned to the pole area Grooves (at full load) carry currents of the same size, while the currents that of the pole gap are assigned, for machines with passive rotor (Fig. 6) or with mixer excitation (Fig. 8) Determine the idle field while under (exclusive) excitation are zero due to permanent magnets. 6. Electrical machine with laminated according to the above claims executed Excitation part, indicated by the fact that the coils with their connections led out, the currents are individually adjustable and the pole gap assigned Coils in machines with armature excitation with their currents an adjustable no-load field enable. 7. Electrical machine with laminated according to the above claims executed Excitation part, that is, that the number of phases and with it the number of slots per pole pitch is odd, preferably 5 or 7. 8. Electric machine or magnetic support assembly with the above Claims laminated executed exciter part, d a d u r c h characterized that the adjustability of the magnetic field by the stray flux increasing adjusting elements (Control elements K in Fig. Lo and Fig. 12) is achieved. 9. Electrical machine and / or magnetic support assembly with after The above claims laminated exciter part, characterized in that the adjustability of the magnetic field by a displaceable parallel to the magnet plane arranged grid of soft iron elements achieved in the division of the pole lamellas will. 10. Electrical machine and / or magnetic support assembly with after the above claims and claim 7 described features d a d u r c h g e .k e n n z e i c h n e t that the actuating force for the displacement of the lattice-shaped actuating element is generated by electrical currents in conductors between the soft iron lamellas flow and the magnetic reaction force by a spring or equivalent Element is compensated. 11. Electrical machine with laminated passive exciter part, in particular according to claim 5, characterized in that in the slots Permanent magnet material with the direction of magnetization between the soft iron lamellas is used transversely to the lamellar plane, so that the field of the armature winding (e.g. at Full load) is compensated.