WO2011128842A2 - Method and device for the magnetization of magnetic material pieces of a rotor in a permanently excited synchronous machine, and rotor for such a synchronous machine - Google Patents

Abstract

The invention relates to a method and a device for magnetizing magnetic material pieces (13A, 13B, 13C) of a rotor (5) in a synchronous machine, in particular hybrid synchronous machine (1),as well as a rotor (5). In the method, the magnetic material pieces (13A, 13B, 13C), which are embedded in the rotor (5) and which are originally unmagnetized, are magnetized by means of the use of a magnetization coil (17) of a magnetization device (18). Provision is made,in the vicinity of the magnetic material pieces (13A, 13B, 13C),for closed hollow spaces (15A, 15B, 15C), which can only be accessed in axial direction, for simplifying the assembly and for shortening the magnetization clock times in the rotor (5). The magnetization of the embedded magnetic material pieces (13A, 13B, 13C) into permanent magnets (13D, 13E, 13F) of the preassembled rotor (5) is carried out by means of at least two or more magnetizing magnetization coils (17), which are at least partially inserted into the hollow spaces (15A, 15B, 15C). The magnetization coils (17) are preferably separated.

Description

METHOD AND DEVICE FOR THE MAGNETIZATION OF MAGNETIC MATERIAL PIECES OF A ROTOR IN A PERMANENTLY EXCITED SYNCHRONOUS MACHINE, AND ROTOR FOR SUCH A SYNCHRONOUS MACHINE

[0001 ] This application claims benefit of priority to prior U.S. provisional application no. 61/324,689 filed on April 15, 2010, and as a non-provisional thereof; this application also claims benefit of priority to prior European application no. 10160091 filed on April 15, 2010; the entirety of European application no. 10160091 and of U.S. application no. 61/324,689 are expressly incorporated herein by reference in their entirety, for all intents and purposes, as if identically set forth herein.

TECHNICAL FIELD

[0002] The instant invention relates to a method and a device for the magnetization of magnetic material pieces (insertion magnets or buried magnets, respectively) of a rotor of a synchronous machine comprising a permanent magnet excitation, in particular a hybrid synchronous machine (HSM) according to the preamble of claims 1 and 9.

[0003] The invention further relates to a rotor comprising magnetic material pieces, which are to be magnetized, for such synchronous machines according to the preamble of claim 1 1 .

[0004] The invention relates in particular to a magnetization technology, which facilitates the production process of rotors for certain embodiments of permanently excited synchronous machines according to claim 1 1. There are rotors for hybrid synchronous machines, in which the permanent magnets are arranged on top of one another within the rotor - viewed radially in a plurality of plies and layers, respectively.

[0005] Such hybrid synchronous machines encompass a high degree of efficiency of > 0.9 in response to a constantly high power factor of > 0.8 across the entire operating range. Their main advantage is the ability to easily weaken the field, whereby an rpm-range of a constant actual power output of at least 1 :3 can be attained. The hybrid synchronous motors are thus used in a highly advantageous manner with regards to the system efficiency in comparison to other forms of permanently excited motors for electrical drives for road vehicles, in particular for electro-mobiles/ automobiles.

STATE OF THE ART

[0006] As is known, motors an efficiency that is constant across a very large rpm- range, are electrical drives for road vehicles. With this motor characteristic, the mechanical transmissions comprising a variable conversion - whether it is embodied in stages or continuously - have to be omitted for the most part. The necessity of mechanically separating the drive train during the shifting operation by means of a clutch is then also omitted.

[0007] Among the known motor types, which can be suitable for this specific purpose for road vehicles, the asynchronous machine and the current-excited synchronous machine without permanent magnets are known. Among the permanently magnetized synchronous motors, however, only very specific embodiments are suitable for this purpose.

[0008] In the case of hybrid-excited synchronous motors, the equipment with permanent magnets leads only to a partial excitation of the magnetic circuit; the rest takes place during operation via a current component, as needed. For this purpose, uninterrupted flux paths must be embodied in the rotor, which cross the axis of the permanent magnetization at a right angle, however without interacting with it.

[0009] This requires the radial arrangement of the magnets in a plurality of, but in at least two layers - typically as buried magnets (that is, magnets, which are completely surrounded by or embedded in the rotor material in radial direction in the assembled state with reference to the rotor axis). For reasons of producibility, practical embodiments for pole segments of an arc length of below 0.07 m are limited to two layers, for pole arcs up to 0.1 m at the borehole periphery of the shaft bore measured in the rotor they are limited to three layers and for even larger poles to four layers. This arrangement, together with the uninterrupted flux path at right angles to the magnetization axis (q-axis), characterizes the hybrid synchronous machine, which is known per se. [0010] Contrary to the other embodiments of permanently excited synchronous motors comprising buried magnets, where the permanent magnets are accommodated either directly below the rotor surface or in a V-shaped manner in the interior of the rotor, the permanent magnets in the case of hybrid synchronous motor are located on top of one another in two or more layers and are orthogonal to the magnetization axis.

[001 1] Magnetization devices are known per se according to the state of the art, but are currently only suitable for magnetic arrangements at or in a layer on or directly below the rotor surface. In the case of multi-layer magnet arrangements, the danger exists in the case of common magnetization devices that the flux density of at least 3.1 T, which is required for the permanent and complete magnetization of the magnet bodies, is not attained or not evenly in all areas of the magnet body. Simulations have shown that this is also the case in the case of highly reluctant hybrid synchronous machines when the shaft bore of the rotor is used by the magnetization device itself (see US 2006/0103254 A1 ).

[0012] A multi-layer magnet arrangement in a permanent magnet machine, which encompasses some, but not all of the features of a hybrid synchronous machine, is known from Publication DE 102008026543A1 . This permanent magnet machine comprises a rotor, which supports the embedded (buried) permanent magnets. The rotor is surrounded by a stator, which comprises static magnetization coils. It was thereby the goal to provide only a portion of the magnetization via permanent magnets and to dimension the permanent magnets such that they are capable to withstand the demagnetization field during operation and in the event of a fault. This is to be attained in that each layer of permanent magnets is disrupted by an iron rod in the magnetization axis. This unburdens the magnets, mainly in the event of a fault, from the penetrating opposing field. However, simulations show that the iron rods are mainly suitable only for the mechanical stabilization of the structure in response to high motor speeds.

[0013] The magnets of such machines are typically inserted into the provided compartments (magnet pockets) in the rotor. However, due to the fact that such magnets have a high magnetic force and the rotor as a whole is highly ferromagnetic, the insertion of the magnets requires some expenditure of force and finesse. [0014] To avoid having to insert pre-magnetized magnets, it was thus proposed to magnetize the magnets in situ. According to the invention, "in situ" means in practice: The magnetization treatment is carried out on location of the material piece.

[0015] In practice, however, the magnetization of such machines comprising buried magnets is extremely difficult, because the permanent magnets in the case of the HSM are not arranged at the surface of the rotor, where the flux density of possible external magnetization coils can be chosen to be so large that the magnetization of the permanent magnets could take place completely and safely. In the case of machine types of the HSM, the buried magnets in the interior of the rotor cannot be reached by external magnetization coils like peripheral magnets.

[0016] However, these of all machine types (HSM) - as already mentioned - have a considerable disadvantage in the event that already premagnetized permanent magnets are used, because they are not accessible to a magnetization from the outside. Due to the large magnetic forces emanating from the fully magnetized magnetic material piece (magnets), the equipment operation is procedurally difficult and cannot be automated according to the current state of the art. In addition, the logistic and security-related effort increases considerably in response to the material flux of magnetized workpieces. Currently, these disadvantages complicate the wider use of the hybrid synchronous machine when used in large numbers, such as they occur in the case of the automobile industry, for example. A method, which facilitates the production of a hybrid synchronous machine, has thus been sought.

[0017] Drive motors for windshield wipers or sunroofs of vehicles, as well as a method for producing the rotors thereof from an annular disk of a material, which can be magnetized, are known from publication EP0981457B1 . It was thereby the goal of the applicants to produce different pole numbers on a neutral component of a material, which can be magnetized, for different vehicle types. When such a workpiece can be transferred into the respective embodiment only shortly prior to its installation or, if necessary, after its installation, by magnetization according to a certain magnetization pattern, this simplifies the storage and material fluxes in the production process considerably. However, due to a lack of buried magnets, these known rotors cannot be used as hybrid synchronous machines. Due to the fact that these known motors were also provided only for driving wind- shield wipers or sun roofs, which lies far away from the object of the instant invention, a person of skill in the art would furthermore not look to borrow anything from these small motors for large high-performance drive motors for the propulsion of vehicles.

[0018] A method for the magnetization of embedded (buried) permanent magnets of a wind generator is known from EP 1926196A2, wherein one open recess, which can be accessed from the outside from radial direction, is in each case embodied between adjacent rotor poles. On the one hand, this additional recess serves the purpose of a cooling air supply and is furthermore used for the magnetization operation, in that a magnetizing magnetization coil is placed into this open recess. The efficiency of such a magnetization is low, because the magnetizing magnetization coil can only be arranged at quite a distance from the permanent magnets, which are to be magnetized. Control fluxes thus create high losses in response to the magnetization operation.

NATURE OF THE INVENTION

[0019] The invention is thus based on the object of avoiding the afore-mentioned disadvantages of common solutions according to the state of the art, so as to create an improved production technology for synchronous machines, in particular HSM or the like, by means of which buried magnets in these machines, in particular also two-layer and multi-layer permanent magnet arrangements can be magnetized in the rotor comprising preassembled unmagnetized magnetic material pieces in a simpler and more effective manner, and wherein the magnetization power loss is also avoided, if applicable.

[0020] In addition, the installation and removal of magnetization coils is simplified and magnetization clock times are shortened.

[0021] As a whole, the production of a rotor comprising buried magnets is carried out in a procedurally simpler and more secure manner and with shorter clock times as compared to the state of the art by means of the invention. The posed object is solved according to the invention by means of the features of the method of independent claim, as well as by means of a magnetization device according to independent claim 9, and by means of a proposed rotor according to independent claim 1 1 . [0022] Preferred embodiments are specified in the dependent claims. The invention relies on the knowledge that the insertion of a magnetized permanent magnet into the compartments in the rotor packet provided for this purpose is laborious and problematic from a safety-related aspect during the production process. A danger of injury to assembly personnel is possible. According to the invention, the rotor packets are thus equipped with unmagnetized or low-magnetized permanent magnet material pieces and are subsequently magnetized permanently and completely in situ by means of the magnetization device according to the invention.

[0023] On one hand, the nature of the invention, in a preferred embodiment, lies in the separated embodiment of the magnetizing magnetization coil such that, during the in situ magnetization operation, it is simply guided closely to the preassembled magnetic material pieces, which are to be magnetized, while using the hollow spaces of the rotor, which can neither be accessed from the inside nor from the outside. The axial magnetization coil parts are accurately adapted to the shape of available cavities/hollow spaces of the rotor in the area of the compartments for this purpose and can thus be inserted into the rotor elements, which are to be magnetized, from axial direction.

[0024] Not only is it possible to considerably increase the magnetic magnetization field intensity for the magnetization of the permanent magnets by means of these measures as compared to the state of the art, but the homogeneity of the magnetic field also improves positively, thus the parallelism and density of the magnetic flux lines in the workpiece, which is to be magnetized.

[0025] By using the invention, the in situ magnetization of permanently excited synchronous motors, which are embodied in a plurality of layers, in particular hybrid synchronous motors (HSM) can be carried out in an efficient and effective manner during the production process. In the case of the hybrid synchronous motors (HSM), the permanent magnets are arranged in two or more plies or layers, respectively, on top of one another. This has the advantage that a considerable portion of the torque is gained from the magnetic reluctance. A further advantage of this magnetic arrangement is that this portion of the magnetic reluctance moment can now be controlled via the magnetic flux at right angles to the permanent magnetization direction and thus makes a large area of constant power across a very wide motor speed range (field weakening) accessible to the synchronous machine.

[0026] According to a further feature of the invention, a plurality of magnetization coil windings, but at least three, are preferably introduced into the interior of the rotor in addition to the outer windings of the magnetization coils for the in situ magnetization, wherein the windings located radially outwards and radially inwards also take over the function of "magnetic lenses", that is, a predetermined steering of the magnetic field lines, to further homogenize the magnetization field for the inserted magnetic material pieces.

[0027] A considerable advantage of the invention is the surprisingly efficient magnetization, that is, the ratio of the used energy from the magnetization device into the energy, which is then permanently stored in the permanent magnets. According to our experiences, this ratio becomes particularly large due to the proximity of the magnetizing magnetization coil windings to the magnets in the interior of the rotor.

[0028] According to a further advantage of the invention, the clock times, which are limited by the electric recharging of the magnetization device, are shortened by the higher efficiency. In the event that 450 J are stored in a rotor comprising 2 kg of magnetic material, e.g., the energy, which is briefly stored during the magnetization operation in the field of the magnetization device, is approx. 100 times greater. However, the operation of a magnetization device, is associated with very high losses in the magnetization coils, so that a rotor could only be magnetized every 3 minutes, e.g., in response to a continuous power accommodation of around 20 kilowatts from the mains.

It can clearly be seen from the above example how advantageous it is to limit the concentration of the magnetizing field during the magnetization operation to only those areas, in which workpieces, which are to be magnetized, are located as well.

[0029] In the event that the windings of the magnetization coils are arranged only at the locations of the rotor, which can be accessed from radially inside or outside, as is the case in the state of the art, considerably larger volumes would be permeated by the field of the magnetization device, whereby the power require- ment of the magnetization device as compared to the method according to the invention would increase considerably.

[0030] According to a further advantageous realization of the invention, the permanent magnets, which are embedded on top of one another in two or a plurality of radial plies or layers, respectively, together with the hollow spaces, which connect to the magnetic cavities, form uninterrupted flux barriers, as soon as they are magnetized. A portion of the magnetic flux saturates the narrow bars, which separate the hollow spaces (e.g. air cavities) for the magnetization coils and the magnetic compartments (insertion holes), which are equipped with the now magnetized magnetic pieces from one another. As a result, such motors encompass a very high anisotropy of the magnetic conductivity between main axis (d-axis) and secondary axis (q-axis). "Anisotropy" means here: the physical characteristics of a body are directional. "Magnetic anisotropy" describes the fact that magnetic materials can encompass a preferred direction or preferred plane for the magnetization.

[0031] In the case of rotor embodiments according to the invention, the ratio of the inductance in the q-axis to that in the d-axis is at least 4:1 . As a result, these motors are suitable to emit a constant power across a wide range of speeds.

[0032] As long as the stability of the rotor sheets permits it, provision can preferably also be made in the radially inner area of the rotor for axial hollow spaces, e.g. air cavities, for accommodating additional magnetization coil windings of the magnetization device, because these hollow spaces do not influence the magnetic field of operation to a noteworthy extent during operation of the machine.

[0033] This feature of the invention makes it possible to accommodate additional hollow spaces for further windings of the magnetizing magnetization coil in the interior of the rotor. "Additional" means: more than the number of the usable flux barriers would allow for/require. The volume, which is permeated by the magnetization field, is reduced through this and the direction of the magnetization flux lines is further parallelized at least in the area of the radially innermost permanent magnet in the rotor pole.

[0034] For geometric reasons, this becomes easier, the higher the number of poles of the machine is chosen. For example, there is more space for these addi- tional hollow spaces or cavities, respectively, which can accommodate additional windings of the magnetization coils in the case of 10-pole machines.

[0035] In terms of the invention, the available hollow spaces, e.g. air cavities, which connect to the magnetic pockets (insertion compartments), which together with the magnetic compartment form an uninterrupted flux barrier, are used to arrange the preferably separated magnetization coils at that location.

[0036] During the magnetization operation, these hollow spaces or air cavities, respectively, are filled with the conductors of the magnetization coil such that the magnetization coil windings, the rotor cross section of which can be separated, consist of at least two magnetization coil parts, which can be connected with one another, preferably of two halves, which can be opened and which can be placed into or inserted, respectively, the closed tubular hollow spaces of the rotor and, all of which being connected in series, are closed to form an electric circuit immediately prior to the magnetization.

[0037] The two magnetization coil halves contact one another in the interior or at the outer edge of the rotor packet and thus form an electrically conductive contact for the magnetization current.

[0038] In the case of hybrid synchronous motors according to the invention, the retention bars are embodied in pairs laterally of the solitary magnet as respective flux barrier (also different than described in WO 2009/063350 A2).

[0039] The technology according to the invention has the main advantage that magnetic bodies, which are preassembled through this, but which have are still unmagnetized, can be magnetized in a simple and effective manner in situ in synchronous motors, which are embodied in multiple layers in radial direction. Through this - during the production process of the synchronous machine - the assembly and the orientation of the rotor elements, which are to be installed, is simplified and facilitated to a large extent.

[0040] The directions of the technical improvements in terms of the invention can be grouped as follows:

A special in situ magnetization technology (method and device), in the case of which the proposed plurality of magnetization coils are embodied so as to be ca- pable of being separated, that is, so as to consist of a plurality of parts, so that they can easily be inserted into the interior of the preassembled rotor laterally to the magnetic compartments. Very short clock times can be realized through this.

[0041] A special arrangement of the separated magnetization coils in the rotor packet such that they can be guided as closely as possible to the magnetic material pieces (permanent magnets), which are to be magnetized. On the one hand, this decreases the required magnetization power relative to the state of the art and, on the other hand, the magnetization parameters can be maintained in narrow tolerances.

[0042] The rotor geometry according to the invention is embodied such that it provides as much space as possible to the permeating current-guiding conductors of the magnetization coil in the vicinity of the magnetic compartments. This measure has the advantage that the power loss in the magnetization device remains small and that shorter clock times can thus be maintained in response to a lower power consumption. According to the invention, it is possible to use possible cavities and/or flux barriers in the rotor geometry as hollow spaces for the current-guiding parts of the separated magnetization coils.

[0043] The current-guiding parts of the separated magnetization coils are embodied such that they fill the hollow spaces embodied in the rotor geometry or available cavities and/or flux barriers, respectively, with the largest possible mechanical filling factor (> 0.9, that is, 90%). The power loss in the separated magnetization coils can thus be kept relatively small.

[0044] In a preferred embodiment, the rotor consists of disks. If necessary, these rotor disks can be magnetized subsequently or independent on one another, respectively, and can be mounted onto the rotor shaft only in the magnetized state. According to our experiences, a high process stability is attained through this. In the case of a preferred embodiment of the invention, however, the unmagnetized disks of the rotor are first assembled or preassembled, respectively, to form a bundle (packet) and the entire bundle of rotor disks is then magnetized by means of the proposed magnetization device in situ.

BRIEF DESCRIPTION OF THE DRAWINGS [0045] The instant invention will be explained below in more detail with reference to the drawings, the exemplary embodiments and the device according to the invention. In an exemplary manner

[0046] Figure 1 shows a cross section across a segment of a permanent magnet motor (10-pole HSM) according to the invention comprising a magnet, which is preassembled, but which must still be magnetized, in the rotor;

[0047] Figure 2 shows a similar cross section as Fig. 1 , comprising the symbolic field lines of the distribution of the magnetic field intensity in the rotor or in embedded permanent magnets, respectively, during the in situ magnetization method according to the invention;

[0048] Figure 3 shows an alternative of the rotor geometry of an HSM according to Fig. 1 , but in a 6-pole embodiment, with the distribution of the magnetic field intensity during the in situ magnetization method according to the invention;

[0049] Figure 4 shows a schematic perspective view of a preassembled rotor according to the invention comprising current-guiding parts of separated magnetization coils, which are inserted partially;

[0050] Figure 5 shows a perspective view of the rotor of Figure 4, comprising the magnetization coil parts of the magnetization coils, which are connected to one another;

[0051] Figure 6 shows a top view onto an exemplary embodiment of a horizontal rotor sheet according to the invention;

[0052] Figure 7 shows a perspective view of a further exemplary embodiment of a separated magnetization coil according to the invention. The figures are described in a comprehensive manner. The same or equivalent elements are identified in the drawings with the same reference numerals - if needed with different indices.

DESCRIPTION OF EXEMPLARY EMBODIMENTS [0053] Figure 1 shows a partial cross section of an exemplary embodiment of a permanent magnet machine 1 according to the invention, which is embodied in this case as a 10-pole permanently excited hybrid synchronous machine (HSM), in particular for the drive of a hybrid or electric vehicle.

[0054] The permanent magnet machine 1 has a stator 2 comprising a stator element 3, in which a cylindrical internal space 4 is embodied. A rotor 5 is arranged in this cylindrical internal space 4 in a coaxial and rotatable manner. The stator element 3 is provided with magnetization coils (not illustrated) in the known manner. The rotor 5 encompasses a hollow-cylindrical rotor core 5K, in which a plurality of rotor sheets 7, which can be magnetized and which together form a cylindrical rotor packet 6, is stacked (see also Fig. 6). A rotor shaft 8 is arranged in a central opening 9 of the rotor core 5K, which rotates together with the rotor shaft 8 and which thus takes along the rotor packet 6. The rotor core 5K is arranged concentrically in the hollow stator element 3 spaced apart by a predetermined radial air gap 10. The axis of rotation of the rotor 5 is identified with 1 1 in Fig. 1 .

[0055] A plurality of compartments, in the case of this exemplary embodiment three compartments (magnetic pockets) 12A, 12B and 12C, are embodied in each case in each rotor segment, which can accommodate unmagnetized magnetic material pieces 13A, 13B or 13C, respectively. These unmagnetized magnetic material pieces 13A, 13B, 13C become permanent magnets 13D, 13E or 13F, respectively, after the in situ magnetization according to the invention and are identified as such.

[0056] As illustrated in Fig. 1 , the magnetic material pieces 13A, 13B, 13C (in Fig. 3, the permanent magnets 13D, 13E, 13F) in the case of this exemplary embodiment have different cross sections, the thickness and width of which increase constantly, viewed in radial direction starting at the outer magnetic material piece 13C towards the inside. According to Fig. 1 , the magnetic material pieces 13A, 13B, 13C are located parallel to one another and are arranged at a functionally defined distance to one another and as vertically (orthogonally) as possible to the radial center line 14 (main axis or d-axis, respectively) of the illustrated rotor segment.

In terms of the invention, closed (tubular) hollow spaces 15, which can only be accessed from axial direction (in particular air cavities and/or flux barriers), are embodied in the rotor core 5K - in the immediate vicinity of the magnetic material pieces 13A, 13B, 13C, which are embedded in at least two radial layers - with said hollow spaces 15 serving as accommodating spaces for current-guiding parts 16 of separated magnetization coils 17 of a magnetization device 18 in response to the magnetization and which subsequently perform other functions, such as flux barriers or cooling air channels, e.g.. In the event that suitable cavities and/or flux barriers are already available in the rotor geometry, they are used as such hollow spaces 15 according to the invention during the in situ magnetization operation. On the other hand, provision can also be made according to a special embodiment for such cavities specifically for the magnetization. At best, such cavities, which are produced or used, respectively, only for the magnetization, can be filled with rod-shaped material, which is magnetic or unmagnetic, as needed, after the magnetization. This can take place for different reasons, such as for bridging a flux barrier or for balancing, or the like, for example. In the case of a need for magnetic bridging, the rods, which are to be inserted, are preferably embodied of rotor sheet material, which is adhered, if necessary.

[0057] In Figure 1 , the current-guiding parts 16 of the separable magnetization coils 17 of the magnetization device 18 are also illustrated as being inserted into the rotor 5. The in situ magnetization of the magnetic material pieces 13A, 13B and 13C according to the invention can take place through this. The magnetic material pieces 13A, 13B and 13C were not yet magnetized before or during their installation, so as to facilitate the assembly operations and the orientation of the elements in the magnetic compartments. The current-guiding parts 16 of the separated magnetization coil 17 will be described below in more detail in context with Figures 4, 5 and 7. In the instant description and in the patent claims, the term "separated magnetization coil 17" describes a magnetizing magnetization coil, which consists of at least two magnetization coil parts, which are embodied so as to be capable of being connected to one another or being capable of being separated from one another, respectively.

[0058] Figure 2 illustrates a largely homogenous magnetic field with the rotor geometry according to the invention according to Figure 1 during the in situ magnetization method according to the invention. As can be seen here from our test results, we obtained largely parallel magnetic flux lines 19 in the area of the magnetic material pieces 13A, 13B and 13C with tolerable deviations (angle β) of less than 10° from the main axis (d-axis) 14 due to the specific arrangement of the current-guiding parts 16 of the separated magnetizing magnetization coils 17 in all three magnetic material pieces 13A, 13B and 13C.

[0059] The above homogenous magnetic field can also be adapted to different rotor geometries. One example for this can be seen in Figure 3, wherein similar rotor geometry - as in Figures 1 and 2 - is used in the case of a 6-pole permanently excited hybrid synchronous motor (HSM). The magnetic flux lines 19 are here also mostly parallel to the main axis 14 during the in situ magnetization method according to the invention, mainly in the area of the permanent magnets 13D, 13E, 13F.

[0060] It should also be mentioned that possible additional magnetizing magnetization coil windings can also be arranged outside of the rotor core 5K, if necessary, in terms of the invention, so as to further boost the homogeneity and intensity of the magnetic field.

[0061] In Figures 1 and 2, two additional outer magnetizing magnetization coil parts 17K are arranged outside of the rotor core 5K, that is, in the stator element 3 or, at best, at the theoretical location of the stator element - here in the stator element 3 in additional outer hollow spaces 15K. In the set-up according to Figure 3, provision is also made - in addition to the two additional outer separated magnetizing magnetization coils 17K - for additional separated inner magnetizing magnetization coils 17L, which are attached outside of the rotor packet 6 in additional inner hollow spaces 15L (e.g. in the area, which is normally assumed by the rotor shaft 8).

[0062] Figure 4 shows a schematic perspective view of the preassembled rotor 5, that is, the rotor packet 6 with the assembled bundle of the rotor sheets 7, comprising the partially inserted current-guiding parts 16 of the separated magnetizing magnetization coils 17, which are actually parts of the magnetization device 18 according to the invention (not illustrated as a whole). In the case of this exemplary embodiment, the current-guiding parts 16 of the separated magnetization coils 17 are horizontal base rods 16A and vertical rods 16B, which are embodied for permeating into the axial hollow spaces 15 and which are in each case connected in pairs on the bottom to the base rod 16A to form half windings of the separated magnetization coil 17. An assembly technology, in the case of which the current-guiding parts 16A, 16B of the magnetization coils 17 are fixed provi- sionally on a base plate 20 - in their predetermined layers - and the rotor 5, that is, the preassembled bundle of rotor sheets 7, is attached from the top onto the magnetization coil parts 16B, which are still open (Fig. 4), whereafter the remaining magnetization coil parts are then attached from the top, is also possible in the context of the invention. A further current-guiding part 16C of the separated magnetization coil 17 is then attached onto the rods 16B from the top (see Figure 5) as a cross connecting element and establishes an electrically conductive connection between the two correspondingly connected rods 16B in the end point of this movement. The current path is closed for the magnetization current only then (Figure 5).

[0063] In the embodiment illustrated in Figure 5, the windings of the separated magnetization coils 17 are connected in series. A parallel connection of the windings, however, would also be possible, if needed. A magnetization current is introduced at a location (identified with an arrow 21 ), e.g., and is discharged at another location (identified with an arrow 22). The magnetization current serves to excite the magnetization coils 17 and thus to carry out the in situ magnetization method according to the invention.

[0064] A top view onto a further exemplary embodiment of a horizontal rotor sheet 7 according to the invention can be seen in Figure 6. On the one hand, it differs from the exemplary embodiment according to Figures 1 -3 in that only two compartments 12A and 12B are embodied here in each rotor segment, which accommodate a permanent magnet (not shown) in each case. On the other hand, provision is made here in each rotor segment next to the compartments 12A and 12B on both sides for only two closed hollow spaces 15 for accommodating a magnetizing magnetization coil part (not shown) in each case.

[0065] As was illustrated schematically in Figure 6, the thickness D and the width B of the holes or compartments 12 (and accordingly also the thickness and the width of the permanent magnets 13D, 13E, 13F, see also Fig. 3) increase continuously from the outside to the inside - viewed in radial direction. On the other hand, provision is made between the compartments 12 and the hollow spaces 15 in each case for bar widths S, which are only optimized with reference to their mechanical design (Fig. 6), so as to keep the power loss as small as possible in response to the magnetization of the magnetization coil. [0066] A further exemplary embodiment of the current-guiding parts of the separated magnetizing magnetization coil 17 can be seen in Figure 7, which are embodied as U-shaped halves 16D and 16E. The lower part 16D is provided with two journals 23, which can be inserted into openings 24 of the upper part 16E for a positive connection when the lower part 16D is attached to the upper part 16E in reverse.

[0067] However, it must be emphasized that further embodiments of the magnetizing separated magnetization coils, of the permanent magnets and of the rotor geometry as well as of the in situ magnetization method are possible in the context of the invention, for which, however, a person of skill in the art in this field would not need any further technical embodiment or instructions, respectively - with the knowledge of the instant disclosure of the invention.

[0068] The mode of operation of the finished permanent magnet machine 1 (HSM) according to Figures 1 -2 and 4-5, which has been magnetized in situ, is as follows:

[0069] Electric current is supplied to the magnetization field coils of the stator 2 such that the polarities of the magnetization field coils change sequentially. Consequently, a magnetic rotating field, which is induced into the rotor, is created at stator teeth. A magnetic field is also created in the rotor 5, in that the in situ magnetized permanent magnets 13D, 13E and 13F create such a magnetic field. The magnetic field of the rotor 5 follows the magnetic rotating field, which is directed against the rotor at the stator teeth. As a result, a rotation or a torque, respectively, of the rotor 5 is thus created, which can be sampled as torque force at the rotor shaft 8.

[0070] To bring the permanent magnets 13D, 13E and 13F into their field- supplying state, provision is made for the special arrangement of the current- guiding parts 16 of the magnetizing separated magnetization coils 17 within the rotor 5 in the vicinity of the magnetic material pieces 13A, 13B and 13C, as well as for the rotor geometry according to the invention in response to the magnetization. Through it, magnetic flux lines 19, which are parallel to one another, are attained at least in the area of the magnetic material pieces 13A, 13B and 13C (the permanent magnets 13D, 13E and 13F) and a homogenous magnetic field is attained in response to the in situ magnetization. [0071] According to the technology according to the invention, a flux density of at least 3.1 T is applied in response to the in situ magnetization of the embedded magnetic material pieces 13A, 13B and 13C by means of the separable magnetizing magnetization coils 17. If needed, the in situ magnetization of the magnetic material pieces 13A, 13B and 13C into permanent magnets 13D, 13E and 13F can be carried out in the preassembled rotor 5 in partial magnetization operations (e.g. per rotor pole sector) of the rotor 5. However, in the event that the rotor is assembled from partial disks, these are treated accordingly, so as to magnetize the magnetic material pieces embedded therein before the partial disks are assembled to form the rotor.

[0072] The above important results of the invention are associated with considerable advantages, which have already been mentioned above and which are inconceivable from the known magnetization methods and magnetization devices or rotor superstructures, respectively.

[0073] With the above advantages, the invention can be used, in particular in the case of electric machines and generators, in particular for traction drives, for production processes, to improve production methods, and to reduce production risks, etc.

LIST OF REFERENCE NUMERALS

1 permanent magnet machine

2 stator

3 stator element

4 cylindrical interior

5 rotor

5K rotor core

6 rotor packet

7 rotor sheet

8 rotor shaft

9 opening

10 air gap

1 1 axis of rotation of the rotor

12A-12C insertion holes or compartments, respectively for embedded magnetic material pieces or permanent magnets, respectively

13A, 13B, 13C unmagnetized magnetic material pieces

13D, 13E, 13F magnetized permanent magnets

14 radial center line/d-axis/main axis

15; 15K, 15L hollow spaces for magnetization coil parts

16A-16E current-guiding magnetization coil parts

17; 17K, 17L separated magnetizing magnetization coil

18 magnetization device

19 magnetic flux lines

20 base plate

21 arrow

22 arrow

23 journal

23 openings

D thickness

B width

S bar width

β (beta) angle

Claims

1 . A method for magnetizing preassembled, unmagnetized magnetic material pieces, which are arranged at least in two layers, of a rotor of a synchronous machine comprising permanent magnet excitation, in particular of a hybrid synchronous machine (1 ), in the case of which the preassembled, unmagnetized magnetic material pieces (13A, 13B, 13C) are magnetized in the rotor (5) by means of the use of a magnetization coil (17) of a magnetization device (18), characterized in that provision is made in response to the production of the rotor (5) in the vicinity of a matching pair of its magnetic material pieces (13A, 13B, 13C), which are arranged at least in two layers, for closed, tubular cavities (15A, 15B, 15C), which can only be accessed in axial direction from both sides, into which hollow spaces (15A, 15B, 15C) at least one magnetization coil (17) of the magnetization device (18) is inserted for the in situ magnetization of the embedded magnetic material pieces (13A, 13B, 13C) into permanent magnets (13D, 13E, 13F), and is subsequently excited with magnetization current.

2. The method according to claim 1 , characterized in that the excitation current is chosen such that a magnetic flux density of at least 3.1 T (Tesla) is generated or provided, respectively, in response to the in situ magnetization of the embedded magnetic material pieces (13A, 13B, 13C) by means of the magnetizing magnetization coils (17).

3. The method according to claim 1 or 2, characterized in that the at least one magnetizing magnetization coil is embodied as separated magnetization coil (17) of at least two magnetization coil parts or current-guiding parts (16A-16E), which can be separated, and which are removed completely from the hollow spaces (15A, 15B, 15C) of the preassembled rotor (5), which can only be accessed in axial direction, after the in situ magnetization of the magnetic material pieces (13A, 13B, 13C).

4. The method according to one of claims 1 to 3, characterized in that provision is made in the rotor (5) for hollow spaces (15A, 15B, 15C), which are embodied as flux barriers, which are used for accommodating the magne- tization coils (17) or the current-guiding parts (16A-16E) thereof, during the in situ magnetization.

5. The method according to one of claims 1 to 4, characterized in that the in situ magnetization of the magnetic material pieces (13A, 13B, 13C) into permanent magnets (13D, 13E, 13F) is carried out prior to the assembly of the rotor (5), in that partial rotor disks of the rotor (5) comprising preas- sembled partial disk magnetic material pieces are magnetized in situ and the rotor partial disks are assembled subsequently to form the rotor.

6. The method according to one of claims 1 to 5, characterized in that provision is also made to increase the magnetization magnetic field in the embedded magnetic material pieces (13A, 13B, 13C) in the rotor (5) during the magnetization process for additional hollow spaces (15K, 15L) - which are magnetically ineffective in response to the operation of the machine (1 ) - and which are provided exclusively for preferably temporarily accommodating additional magnetizing magnetization coils (17K, 17L) in interior, inaccessible areas of the rotor (5) or of the machine (1 ), respectively, viewed in radial direction.

7. The method according to one of claims 1 to 6, characterized in that the cross section of the current-guiding parts (16A-16E) is chosen to be so large that the hollow spaces (15) are filled with a filling factor of at least 90% by means of the separated magnetization coils (17) or the current- guiding parts (16A-16E) thereof, to reduce the Joule effect losses in the current-guiding parts of the magnetization device (18).

8. The method according to one of claims 1 to 7, characterized in that at least three magnetizing magnetization coils (17) are introduced in each rotor pole sector into the interior of the rotor core (5K) so as to be radially spaced apart from one another, wherein the magnetization coils (17) located radially outwards and radially inwards are embodied and controlled or excited, respectively, such that they are used as "magnetic lenses" for the predetermined guidance of the magnetic flux lines (19) for the homo- genization of the magnetization field for the magnetic material pieces (13A, 13B, 13C) during the magnetization operation.

9. A device for magnetizing embedded magnetic material pieces into permanent magnets of a rotor (5) of a synchronous machine comprising a permanent magnet excitation, in particular a hybrid synchronous machine (HSM), in particular for carrying out the method according to one of claims 1 to 8, with said device encompassing a magnetizing magnetization coil (17) comprising current-guiding parts, characterized in that the device is provided with at least two separated magnetization coils (17), the current- guiding parts (16A-16E) of which are embodied so as to be capable of being in inserted into closed hollow spaces (15) of the preassembled rotor (5), which can only be accessed in axial direction, for the in situ magnetization of the magnetic material pieces (13A, 13B, 13C) into permanent magnets (13D, 13E, 13F).

10. The device according to claim 9, characterized in that each separated magnetizing magnetization coil (17) consists of at least two current- guiding parts (16A, 16B, 16C; 16D, 16E), which can be connected to one another.

1 1 . A rotor for a synchronous machine comprising a permanent magnet excitation, in particular hybrid synchronous machine (HSM), comprising embedded unmagnetized magnetic material pieces (13A, 13B, 13C), in particular for use in a method according to one of claims 1 to 8, in the case of which the unmagnetized magnetic material pieces (13A, 13B, 13C) or the magnetized permanent magnets (13D, 13E, 13F), respectively, are embedded in compartments (12A, 12B, 12C) of a rotor core (5K), characterized in that the unmagnetized magnetic material pieces (13A, 13B, 13C) are inserted into the compartments (12A, 12B, 12C) of the preassembled rotor (5); and that provision is made in the rotor (5) for hollow spaces (15), which serve as flux barriers in the vicinity of the compartments (12A, 12B, 12C), which are embodied as closed hollow spaces (15), which can only be accessed in axial direction in each case for at least partially accommodating a separated magnetizing magnetization coil (17) for the in situ magnetization of the magnetic material pieces (13A, 13B, 13C) into permanent magnets (13D, 13E, 13F).

12. The rotor according to claim 1 1 , characterized in that all of the air cavities or flux barriers, respectively, which are present in the rotor core (5K), are embodied as hollow spaces (15) in each case for at least partially accommodating a magnetizing magnetization coil (17).

13. The rotor according to claim 1 1 or 12, characterized in that the rotor (5) is assembled to form a cylindrical rotor packet (6) of unmagnetized rotor sheets (7).

14. The rotor according to one of claims 1 1 to 13, characterized in that the hollow spaces (15) for the separated magnetization coils (17), as well as the compartments (12) for the magnetic material pieces (13A, 13B, 13C) or the permanent magnets (13D, 13E, 13F), respectively, are arranged or embodied, respectively, in each rotor pole sector of the rotor core (5K) so as to be mirror-imaged to the radial pole axis (14).

15. The rotor according to one of claims 1 1 to 14, characterized in that the compartments (12A, 12B, 12C) are embodied in the rotor core (5K) so as to be parallel to one another and so as to be vertical to the radial pole axis (14) at predetermined intervals from one another.

16. The rotor according to one of claims 1 1 to 15, characterized in that the cross sectional surface and/or the thickness (D) and/or the width (B) of the compartments (12) and accordingly the thickness and the width of the magnetic materials pieces (13A, 13B, 13C) or of the permanent magnets (13D, 13E, 13F), respectively, increase constantly - viewed from radially outwards to radially inwards.

17. Apparatus for magnetizing permanent magnets in a rotor comprising:

a base plate;

a first circumferential array of current-guiding magnetization coil parts configured to receive a cylindrical rotor portion, said first circumferential array of current-guiding magnetization coil parts disposed circumferentially around a received cylindrical rotor portion, said first circumferential array of current-guiding magnetization coil parts extending from said base plate in the direction of an axis of said received cylindrical rotor portion; and,

a second array of current-guiding magnetization coil parts extending from said base plate in the direction of the axis of said received cylindrical rotor portion, each one of said second array of magnetization coil parts respectively ex- tending through a respective axially extending internal tubular hollow space in said cylindrical rotor portion.

18. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

each of said second array of magnetization coil parts extending through a respective axially extending flux barrier of said cylindrical rotor portion.

19. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

each of said second array of magnetization coil parts extending through a respective axially extending air cavity of said cylindrical rotor portion.

20. The apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, wherein:

at least one of said second array of magnetization coil parts fills the respective internal tubular hollow space through which it extends with a mechanical filling factor greater than ninety percent.

21 . Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

a cross-connecting conductor;

at least one of said first array of current-guiding magnetization coil parts having a respective terminus to its respective extent from said base plate in the direction of the axis of said received cylindrical rotor portion;

at least one of said second array of current-guiding magnetization coil parts having a respective terminus to its respective extent from said base plate in the direction of the axis of said received cylindrical rotor portion; and,

said cross-connecting conductor being connected, over a radial and arcuate extent of said received cylindrical rotor portion, to electrically connect said terminus of said at least one of said first array of current-guiding magnetization coil parts to said terminus of said at least one of said second array of current- guiding magnetization coil parts.

22. The apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, wherein: said axially extending internal tubular hollow spaces in said cylindrical rotor portion are open, only at their respective ends, to entry of respective ones of said second array of magnetization coil parts.

23. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

a horizontal base rod supported by said base plate, said horizontal base rod connecting two current-guiding magnetization coil parts of said first circumferential array of current-guiding magnetization coil parts.

24. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

said cylindrical rotor portion including a plurality of stacked rotor sheets.

25. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 17, further comprising:

each of said second array of magnetization coil parts extending through a respective axially extending flux barrier of said cylindrical rotor portion; and,

said second array of magnetization coil parts forming pairs, each said pair of magnetization coil parts being symmetrically arranged within corresponding pair of symmetrically arranged flux barriers in a respective sector of said cylindrical rotor portion.

26. Apparatus for magnetizing permanent magnets in a rotor as claimed in claim 25, further comprising:

each said symmetrically arranged pair of flux barriers and pair of magnetization coil parts is disposed symmetrically relative to a magnet compartment in said respective sector of said cylindrical rotor portion.

27. An arrangement for magnetizing permanent magnets in a rotor comprising: a rotor pole segment;

a plurality of magnet compartments in said rotor pole segment;

unmagnetized magnetic material pieces in each of said plurality of magnet compartments;

a plurality of axially-extending flux barrier tubular internal hollow spaces in said rotor pole segment; and, a plurality of magnetization coil parts configured to controllably magnetize said unmagnetized magnetic material pieces in said magnet compartments, each of said plurality of magnetization coil parts extending into a respective flux barrier hollow space of said rotor pole segment.

28. The arrangement for magnetizing permanent magnets in a rotor as claimed in claim 27, wherein:

at least two of said magnet compartments are orthogonal to a radial pole axis of said rotor pole segment; and,

magnetic compartment cross sectional area increases for radially inner magnetic compartments relative to radially outer magnetic compartments on said radial pole axis.

29. An arrangement for magnetizing permanent magnets in a rotor as claimed in claim 28, further comprising:

at least one of said magnetic compartments is respectively separated from associated first and second ones of said plurality of axially-extending flux barrier tubular internal hollow spaces by a respective first narrow bar, respectively, and a respective second narrow bar, respectively; and,

said first and second ones of said plurality of axially-extending flux barrier tubular internal hollow spaces are symmetrical relative to the radial pole axis of said rotor pole segment.

30. The arrangement for magnetizing permanent magnets in a rotor as claimed in claim 29, wherein:

said first and second ones of said plurality of axially-extending flux barrier tubular internal hollow spaces are in the form of segments of a U-shape opening towards the radially outer direction.

31 . The arrangement for magnetizing permanent magnets in a rotor as claimed in claim 27, wherein:

at least one of said magnetization coil parts fills the respective flux barrier hollow space through which it extends with a mechanical filling factor greater than ninety percent.

32. A process for magnetizing permanent magnets in a rotor comprising steps of: placing unmagnetized magnetic material pieces in a plurality of magnet compartments of a rotor pole segment;

axially inserting a plurality of current-guiding magnetization coil parts into respective axially extending internal tubular hollow spaces in the rotor pole segment; and,

supplying electric current to the plurality of current-guiding magnetization coil parts to effect in-situ permanent magnetization of the magnetic material pieces within the magnet compartments.

33. A process for magnetizing permanent magnets in a rotor as claimed in claim 32, further comprising steps of:

using axially extending flux barrier cavities of the rotor pole segment as the axially extending internal tubular hollow spaces in the rotor pole segment; and,

disposing the axially extending flux barrier cavities symmetrically relative to a magnet compartment of said rotor pole segment.

34. A process for magnetizing permanent magnets in a rotor as claimed in claim 32, further comprising the step of:

filling at least one axially extending internal tubular hollow space with an axially inserted current-guiding magnetization coil part to a filling form factor of greater than ninety percent.

35. A process for magnetizing permanent magnets in a rotor as claimed in claim 32, further comprising steps of:

providing magnet compartments of the rotor pole segment in orthogonal orientation relative to a radial pole axis of the rotor pole segment; and,

sizing the orthogonally oriented compartments so that compartment cross sectional area increases for radially inner magnetic compartments relative to radially outer magnetic compartments on said radial pole axis.

36. A process for magnetizing permanent magnets in a rotor as claimed in claim 32, further comprising the step of:

forming the rotor pole segment from a plurality of stacked rotor sheets.