WO2005117243A1

WO2005117243A1 - Synchronous electromechanical transformer

Info

Publication number: WO2005117243A1
Application number: PCT/SI2005/000015
Authority: WO
Inventors: Marko Petek
Original assignee: Meier, Mojca; Petek, Alenka; Petek, Maja Marija
Priority date: 2004-05-25
Filing date: 2005-05-23
Publication date: 2005-12-08
Also published as: WO2005117243B1; SI21830A; EP1884013A1

Abstract

The invention relates to a synchronous electromechanical transformer that can be used as a multi-phase motor and generator, has a high specific torque, a small or negligible stop moment, a small moment irregularity, can be quietly operated, and has good heat permeability between the windings and the housing. It contains a rotor having uniformly distributed magnetic poles (4), and two stators (2) with concentrated windings (8) of at least two electrical phases. The individual stator contains the same number of similarly arranged electromagnetic poles (9) of each of at least two electrical phases arranged in related groups (7) of at least two electromagnetic poles of the same electric phase. The stator poles (9) can contain magnetically permeable polar cores and can be uniformly or non-uniformly distributed. The number of electromagnetic poles of the stator differs from that of the rotor by the product between the number of stator groups (7), the electromagnetic poles of said stator groups pertaining to the same electrical phases, and a natural number that is not a multiple of the number of electrical phases. A radial, axial and linear embodiment of the transformer is possible.

Description

SYNCHRONOUS ELECTROMECHANICAL TRANSFORMER

TECHNICAL FIELD The invention relates to a synchronous electromechanical converter. It can be classified according to the international classification in H02K16 / 04, H02K21 / 12, H02K26 and HO 2K 1/06. The invention solves the problem of designing a multi-phase synchronous electromechanical converter with concentrated windings, which has a large torque, a very small or negligible cogging torque, a small one

Torque unevenness, minimal moment of inertia, small vibrations and large ones

Has heat permeability between the turns and the housing.

PRIOR ART According to most known solutions, the electromagnetic poles contain magnetically permeable pole cores. In order to achieve a small cogging torque, the number of electromagnetic poles and the number of magnetic poles differ from one another. With regard to the design of the electromagnetic part, the solutions can be divided into three groups. The first group contains the solutions, each with a rotor and a stator, which are described both in the patents EP0094978, EP0216202, EP0291219, EP0295718, DE10049883, WO2004006415, DE10322018 and the like, which treat the designs with approximately evenly distributed electromagnetic poles and in that Patent EP0454183, where the electromagnetic poles are distributed in sections at the same distance as rotor poles. Compared to those with two stators, the solutions with one stator have significantly poorer thermal permeability between the stator windings and the housing, large mechanical bending loads on the rotor, greater induced rotor vibrations and poorer utilization of the magnetic poles of the rotor. Because of a larger parasite magnetic flux between adjacent electromagnetic poles, the solutions with a stator and a rotor have a smaller specific torque. In the second group are the solutions with two rotors and one stator. Some designs are described in WO03103114, US6664692 and the like. The designs in which the stator is located between two rotors often have a lower mechanical rigidity in the connection between the Stator and the housing. The third group contains the solutions with one rotor and two stators. Such an embodiment is described in the patent specification CA2341272. Its weakness lies in the complex rotor structure, which is expensive to manufacture. The patent DE19856647 describes another embodiment in which the magnets are attached to a magnetically permeable rotor yoke. The design suffers from additional energy losses in the rotor yoke, somewhat lower specific torque and less than optimal use of the magnetic poles. The rotor and stator pole numbers are in a ratio of 4: 3, which is why the design has a moderate cogging torque and synchronism. In cases with higher numbers of poles, losses caused by changing magnetic fields are greater than in cases where the number of rotor poles differs only slightly from the number of stator poles. The phase coupling is large because the neighboring electromagnetic poles belong to different electrical phases. Patent specification CA2444759 describes an axial construction with the ratio of the rotor and stator pole number of 8: 6, the stators being rotated relative to one another. As a result, the cogging torque is reduced a little, while the bending loads on the rotor increase. The properties which are determined by the pole number ratio behave in the same way as in the embodiment according to DE 19856647. The patent specification US5751089 describes a two-phase construction with uniformly distributed stator and rotor poles, the number of which is the same. Both stators are offset from each other by half a pole. This construction has a relatively large cogging torque. The same document also describes the solution with an arbitrary even number of phases, the cogging torque being able to be reduced with an increasing number of phases. However, this solution is impractical because four-phase and multi-phase motor controls are not very common.

TECHNICAL SOLUTION In the invention, a construction with two stators and a rotor located between the two stators is proposed. The design is radial, axial and linear in relation to the shape and mutual position of the rotor and stators

Execution. In some designs, the electromagnetic poles contain magnetically permeable pole cores. Synchronous electromechanical converter, further referred to as a motor, can be used as multi-phase motor and generator can be used. It works with electrical multiphase systems in which the phase difference between adjacent pseudophases is 180 ° divided by the number of phases, which also includes the normal three-phase system and the two-phase system with phases offset by 90 °. The electromagnetic part contains two stators 2 and a rotor 1, which is located between the two stators and can move with respect to them. The stators are rigidly connected to the housing or are themselves part of the housing. The rotor contains approximately evenly distributed, alternately oriented magnetic poles 4. The magnetic poles are oriented approximately parallel to the direction which is rectangular with the magnetic gap between the magnetic poles and the individual stator. The stator contains poles 5 directed against the rotor and one or more magnetically permeable parts 6, through which the magnetic flux between adjacent poles closes on the side that does not adjoin the magnetic gap with the rotor. The stator contains the same number of identically arranged electromagnetic poles each of at least two electrical phases, which are arranged in contiguous groups 7 of at least two electromagnetic poles, all of the electromagnetic poles belonging to the individual group belonging to the same electrical phase and the adjacent electromagnetic poles of the same group being electrically offset by 180 ° are. The number of rotor poles that adjoin the magnetic gap with an individual stator (M) differs from the number of electromagnetic poles of the stator (E) by the product between the number of stator groups whose electromagnetic poles belong to the same electrical phase, (G), and a natural number () that is not a multiple of the electrical phase number (F), M = E ± nG. In order to match the average electrical phase and the average magnetic phase in the area of the individual stator group, the adjacent electromagnetic poles belonging to different stator groups are electrically offset by 180 ° + sgn (- E) (180 ° / F) n. The number n is preferably equal to one, because in this case the average absolute phase difference between the magnetic phase of the rotor and the electrical phase of the stator can be smallest. The magnetic poles of the rotor can be better used in stators that contain groups with larger numbers of electromagnetic poles. If the stator in the rotary design contains more than one stator group of the individual phase, the overall center of gravity of the positions of electromagnetic poles which belong to the same phase preferably coincides with the rotor axis. For rotary versions the number of rotor poles that border the magnetic gap with an individual stator (M), an even number.

BRIEF IMAGE DESCRIPTION The construction is explained in more detail with the aid of a few examples and images, namely: FIG. 1 three-phase radial design, each stator 18 containing uniformly distributed electromagnetic poles with magnetically permeable pole cores and the rotor 20 magnetic poles contains FIGS. 2A and 2B two examples of the Rotor design Fig. 3 three-phase radial design, each stator contains 24 electromagnetic poles with magnetically permeable pole cores, which are distributed in sections at the same distance as the rotor poles, and the rotor contains 26 magnetic poles. 4A to 4F the designs of the stators containing magnetically permeable pole cores. FIGS. 5A and 5B the design of magnetically permeable pole cores from the group of electromagnetic poles, in which the shape of the pole cores changes so that the difference between the magnetic phase of the rotor and 6A to 6E transitions between adjacent stator groups

Contain electromagnetic poles with magnetically permeable pole cores, the distance between adjacent electromagnetic poles belonging to different stator groups being greater than the distance between the adjacent electromagnetic poles of the same stator group Fig. 7 three-phase radial design, each stator 21 containing uniformly distributed electromagnetic poles without magnetically permeable poles and the 8 contains a three-phase radial design, each stator containing 18 uniformly distributed electromagnetic poles with magnetically permeable pole cores and the rotor containing 16 magnetic poles and the stators being rotated relative to one another by 4 rotor poles.

DESCRIPTION OF THE INVENTION The number of rotor poles adjacent to the magnetic gap with an individual stator (M) is the same for the two stators. Those versions stand out particularly in which the individual rotor pole 4 borders on both magnetic gaps and the rotor, with the exception of the poles, contains no magnetically permeable or electrically conductive parts. In such cases, energy losses in the rotor caused by the changing magnetic fields can be minimal. The magnetic poles can be exploited best because the magnetic voltage required to generate the magnetic flux of the rotor poles is the smallest. The forces on the individual rotor pole that do not contribute to the output torque can best be compensated in such cases. At the same time, the torque that acts on the individual rotor pole and causes bending stresses in the rotor can be minimal. To increase mechanical rigidity and magnetic flux between neighboring ones

To close the rotor poles, the rotor in some versions contains a magnetically permeable yoke 11, on which the magnetic poles are fastened from both sides. The mass of the rotor is usually larger than that of a rotor without a yoke, which also results in a larger moment of inertia and a larger heat capacity. Such designs use the magnetic poles somewhat poorly because magnetic flux is closed on one side by the yoke. This and the larger rotor mass result in a slightly smaller specific torque; due to additional energy losses in the yoke, energy losses in the rotor caused by the changing magnetic fields also increase. The magnetic poles of the rotor are preferably distributed such that the positions of the poles on both sides of the yoke match. This is the best way to compensate for the forces and moments that act on a section of the rotor and do not contribute to the output torque. At the same time, it is preferred that balanced magnetic poles on both sides of the rotor are oriented in the same direction, which is why the magnetic poles are better utilized and are easier to magnetize. The magnetic poles can be in relation to the electromagnetic poles in the direction of

The rotor movement can be tilted, which results in smaller torque unevenness and more sinusoidal induced voltage in stator windings, but the greater the tilt, the smaller the torque that can be achieved. With greater inclination, the cogging torque also decreases in the versions which contain magnetically permeable stator poles. With some stator designs, a smaller cogging torque can be achieved by periodically changing the layer spacing of the rotor poles a little. Permanent magnets are preferably used as magnetic poles, with the highest specific torque using magnetic materials based on rare earths can be achieved. Single or multi-pole permanent magnets are used, which preferably have a rectangular shape or are mutually identical segments. The magnets are usually best used when the part they occupy is seventy to eighty-five percent of the circumference of the area adjacent to the magnet gap with an individual stator. The rotor is preferably constructed from magnetic poles 4, which are connected via their sides not adjoining the magnetic gap with stators to the elements 10 made of magnetically non-permeable and electrically non-conductive material, preferably polymers or ceramics. The polymers are preferably reinforced by fillers which improve their mechanical properties and rigidity of the rotor, which contributes to quieter running. Filler can also improve the thermal properties of the rotor and adjust the coefficient of thermal expansion. This is preferably adapted so that the ratio of the two magnetic gap widths is approximately maintained when the temperature changes in the motor. The part of the rotor which contains the magnetic poles is preferably connected to the shaft with the same material or to the parts which are used for connection to the shaft. The rotor is preferably manufactured in such a way that the magnetic poles are distributed accordingly and cast with binding material. Preferably, the connection to the shaft is also established at the same time. The magnets are usually completely cast in, which protects them from corrosion and mechanical damage and also prevents crumbling. For good heat dissipation, it is important that the layer of binding material on the magnetic pole surfaces that adjoin the magnetic gap enables good heat permeability and good heat transfer. A part of the winding 8 belongs to the electromagnetic pole of the phase to which it belongs. Preferably, each electromagnetic pole of the stator group has its own turn, which belongs entirely to it, because such turns have the smallest dimensions and the smallest electrical resistance and also enable the highest turn filling factors and the highest heat permeability between the turns and the housing. The winding of the stator group can also be carried out in such a way that the center points of the windings, which belong to the individual electromagnetic pole of the group, only coincide with its position with every second electromagnetic pole. In such cases, the stator group preferably contains an even number of electromagnetic poles. The winding of the stator group can also be designed as a meander winding, whereby the group preferably contains an even number of electromagnetic poles. The stator poles can be distributed evenly. With such a distribution, the layer spacing of adjacent electromagnetic poles of the same stator group is the same as that of the adjacent electromagnetic poles belonging to different stator groups. The discrepancy between the magnetic phase of the rotor and the electrical phase of the stator becomes ever greater on the transitions between the stator groups. The phase difference between the magnetic and electrical phases is different for each electromagnetic pole of the stator group, so the windings of all the electromagnetic poles of individual stator groups are preferably connected in series, thus preventing the equalizing currents between individual electromagnetic poles and achieving a more sinusoidal curve of the induced voltage in windings. An example of such an embodiment is shown in Figure 1. If the number of rotor poles that border the magnetic gap with an individual stator (M) differs from the number of electromagnetic poles of the stator (E), the electromagnetic poles can be distributed in such a way that the layer spacing of adjacent electromagnetic poles which belong to the same stator group 14 is equal to the average layer spacing of the rotor poles and is smaller than the layer spacing of adjacent electromagnetic poles which belong to different stator groups 12, 13. Such an embodiment is shown in Figure 3. Because of the smallest average absolute phase difference between the magnetic phase of the rotor and the electrical phase of the stator, the highest specific torques can be achieved with such stator designs. If the stator contains electromagnetic poles with magnetically permeable pole cores, such a stator design has a larger cogging torque and a more trapezoidal shape of the induced voltage in the winding than a stator design with uniformly distributed electromagnetic poles. Both can be reduced in part by periodically changing the layer spacing of the rotor poles. The period of change is preferably the same as the number of rotor poles. If the number of rotor poles that adjoin the magnetic gap with an individual stator (M) differs from the number of electromagnetic poles of the stator (E) and the number n is greater than one, the electromagnetic poles of individual stator groups can be distributed evenly so that the number of opposing rotor poles is one third of the rotor pole larger than the number of electromagnet poles of the stator group. The layer spacing of neighboring electromagnetic poles, the different stator groups are by (n - 1) / F of the average layer spacing of the rotor poles larger than the layer spacing of neighboring electromagnetic poles belonging to the same stator group. Because of the smaller average absolute phase difference between the magnetic phase of the rotor and the electrical phase of the stator, higher specific torques can be achieved with such stator designs than with those with uniformly distributed electromagnetic poles, although both have a comparable cogging torque. The stator has two variants with regard to the magnetic properties of the stator poles. In the first variant, the stator poles contain magnetically permeable pole cores 9. The pole cores are separated from the rotor poles by a magnetic gap which is narrow in comparison with the dimension of the rotor pole in the direction of the rotor movement and is preferably the same for all stator poles. Normally, the poles in the vicinity of the magnetic gap widen at least in a direction that is approximately rectangular to the direction of the magnetic field in the magnetic gap, preferably in a direction parallel to the rotor movement. This increases the magnetic flux through the pole, which leads to better utilization of the core material and the current conductors. At the same time, the demagnetizing forces and changing magnetic fields in the rotor poles decrease. The expanded pole consists of a head 16 and a shaft 15, which preferably has parallel sides. The heads of the neighboring poles preferably do not touch. The gap between adjacent heads is preferably larger than the width of the magnetic gap between the pole and the rotor poles. In some versions, the width of the magnetic gap at the edges of the pole core increases, which reduces the cogging torque and the proportion of the higher harmonic frequencies of the changing magnetic fields in the rotor poles. The greater part of the magnetic flux flows through the pole. Variants that contain magnetically permeable poles are mainly characterized by a higher specific torque, better utilization of the magnetic poles of the rotor, smaller changeable magnetic fields in the windings, better utilization of the current conductors and usually also by higher thermal permeability between the windings and the housing. Magnetically permeable poles preferably have a large magnetic permeability, high saturation induction, small magnetic reversal losses and low electrical conductivity. Polkeme are preferably mutually electrical insulated lamellae made of magnetically permeable sheet or film or of magnetically permeable particles or magnetically permeable ferrite cast in the electrically non-conductive material. If the material of the pole cores has anisotropic magnetic properties, the direction with optimal magnetic properties preferably coincides with the direction of the magnetic field in the core shaft 15. The poles 9 are preferably produced in one piece with an associated part of the magnetically permeable stator yoke 6, but can also be produced as independent elements and attached to the stator yoke. The designs that contain part of the stator yoke usually have higher thermal permeability between the windings and the housing. Figures 4A to 4F illustrate some versions of the stators with magnetically permeable pole cores. In the versions on Figures 4A and 4B, the stator is made up of elements which contain the pole core and part of the stator yoke, via which magnetic flux is closed between adjacent pole cores. composed. Electrically insulating gaps 17, which separate neighboring poles from one another, are narrow, so that the magnetic voltage drop is small. With a larger gap area, the magnetic voltage drop at gap 17 is reduced, which is why adjacent elements are preferably separated by oblique gaps, which is shown in Figure 4A. The gaps are preferably filled with an electrically non-conductive, highly heat-permeable binder which electrically insulates the adjacent stator elements, increases the rigidity of the rotor and dampens acoustic vibrations. In the versions in Figures 4C and 4D, the individual stator element contains several poles and the part of the stator yoke that connects them. If both electromagnetic poles belong to the same electrical phase in the design in Fig. 4C, the smallest transformer coupling between the windings of different electrical phases is shown.In the versions in Fig. 4E and 4F, pole cores are produced as independent elements and glued to the stator yoke or with the aid of Pins and grooves attached to the stator yoke. With such designs, it is possible to manufacture the pole turn as an independent part that is placed on the pole core when the stator is assembled. With the exception of the design in Figure 4D, the materials with anisotropic magnetic properties, such as grain-oriented electrical sheet, allow for smaller energy losses in magnetically permeable materials Stator. In the case of the stator designs, in which the electromagnetic poles are evenly distributed, the shape of the poles of individual stator groups can change so that the difference between the magnetic phase of the rotor and the electrical phase of the stator is reduced. This increases the specific torque, but also increases the cogging torque. Electromagnetic poles closer to the transitions between adjacent stator groups typically have asymmetrical pole core heads in such designs, which are also offset by a larger dimension 18 with respect to the core shaft, as shown in Figures 5A and 5B. The stator designs where the distance between the different

Neighboring electromagnetic poles belonging to stator groups is larger than that between adjacent electromagnetic poles of the same stator group, can contain poles 19 with magnetically permeable pole cores which do not belong to any electrical phase and are located between the stator groups. This reduces the changes in the magnetic field at the transitions between adjacent stator groups, which can also be achieved by shaping the pole core heads of neighboring electromagnetic poles, which belong to different stator groups, 12, 13 in such a way that the magnetic gap area with the rotor poles at the transitions between neighboring Statorgmppen enlarged. Some examples of the transitions between adjacent stator groups are shown in Figures 6 A to 6E. In the second variant, all stator poles are also electromagnetic poles and do not contain any magnetically permeable parts. The electromagnetic pole can contain a winding carrier 20, which preferably consists of electrically non-conductive material. Magnetic flux of the electromagnetic pole runs predominantly through the pole turn, which is mainly in the magnetic gap between the rotor and the magnetically permeable stator yoke 6. For this reason, the windings are designed in such a way that the eddy current losses are kept small. The second stator variant is mainly characterized by a negligible cogging torque, absence of magnetic reversal velocities in the pole cores, small changeable magnetic fields in the rotor poles and very simple pole manufacture. Due to the better utilization of the magnetic poles of the rotor, higher specific torques can be achieved with a smaller number of stator groups whose electromagnetic poles belong to the same electrical phase (G). With a larger number of stator poles magnetic flux of the individual electromagnetic pole is smaller, which is why the magnetically permeable stator yoke 6 can have a smaller average. The magnetic poles of the rotor are exposed to smaller demagnetizing forces because the part of the turn that belongs to the individual electromagnetic pole is smaller. Usually, the larger the number of stator poles, the greater the thermal permeability between the windings and the housing. Because the number of rotor poles preferably differs only slightly from the number of stator poles, energy losses caused by changing magnetic fields are greater with a larger number of stator poles, which is particularly true of the variants which contain magnetically permeable stator pole cores. For the stator variants with evenly distributed poles that contain magnetically permeable poles, the cogging torque is proportional to the quotient between the number of stator groups whose electromagnetic poles belong to the same electrical phase (G) and the number of electromagnetic poles of the stator (E). In order to minimize the cogging torque, the stator should therefore preferably contain a large number of electromagnetic poles, which are distributed in a few stator groups. In the case of stators with magnetically permeable pole cores, which contain more than one stator group of each electrical phase, the cogging torque can also be reduced by periodically changing layer spacing of the rotor poles. The cogging torque can also be reduced by an inclination of the stator poles in relation to the rotor poles in the direction of the rotor movement, although this method is impractical for stators which consist of individual poles. The stator preferably consists of the same elements, which contain one or more poles and the part through which magnetic flux closes between adjacent poles. In the case of versions with a higher number of elements, smaller mechanical stresses caused by temperature changes and usually smaller acoustic vibrations occur. The highest winding filling factors and winding densities can be achieved with stators consisting of individual poles, where each pole is wound separately. With separately wound poles, a larger conductor average can usually be achieved with the same winding dimensions, better heat permeability of the winding and better heat transfer between the winding and the pole. All this leads to better heat permeability between the turns and the housing. The magnetically permeable stator yoke 6 can be interrupted between the stator groups, whereby a smaller transformer coupling is achieved between the turns of individual phases, although this normally reduces the specific torque and increases the cogging torque. The stator or its elements are glued to the housing in an electrically insulating manner or fastened with mechanical fastening elements. Contacts between the stator and the housing preferably have good thermal permeability. The number of stator groups of the individual stator whose electromagnetic poles belong to the same electrical phase, (G), is preferably equal to one or two. The number of poles and the pole distribution are preferably identical in both stators. The electromagnetic poles of both stators are preferably electromagnetically equivalent. The stators are arranged with respect to the magnetic poles of the rotor so that the average phase of the turn of the individual electrical phase is approximately synchronous for both stators. The turn of the individual phase preferably forms one or more partial turns connected in parallel. All of the electromagnetic poles of individual stator groups preferably belong to the same partial turn. individual partial windings preferably contain the same number of electromagnetic poles of both stators, with which the equalizing currents between the partial windings are combated, especially when the electromagnetic poles of both stators are not magnetically equivalent. If the stator is designed in a rotary manner with more than one stator group of the individual phase, the entire center of gravity of the pole positions of all the electromagnetic poles which belong to the same partial turn preferably coincides with the rotor shaft. In this way, the bending load on the rotor shaft can be kept small even in the event of the failure of a partial turn or the entire turn of a phase. If both stators have the same number of poles and pole distribution and the positions of the

Magnetic poles of the rotor on both sides of the rotor match, the construction has several variants with respect to mutual displacement of the electromagnetic poles of the first and second stator. In the first variant, the stators are mutually offset in the direction of the rotor movement by at most GI (2E) of the layer spacing of the adjacent rotor poles. Individual partial turns preferably contain the same number of opposing electromagnetic poles of the first and second stator. These variants are characterized by minimal mechanical bending loads on the rotor and minimal excitation effect on the rotor poles, which cause the rotor to vibrate. At the same time, the bending loads on the rotor shaft are kept low, even in the event of the failure of a partial turn or the entire turn of a phase. That is why such construction variants run smoothly. If the stators are not offset from one another, the highest torque can be achieved. In the case of stator variants which contain magnetically permeable poles, the cogging torque can normally be reduced by mutually displacing the stators by GI (2E) of the layer spacing of the adjacent rotor poles and a sinusoidal voltage profile in the windings can be achieved. In the second variant, the stators are mutually offset in the direction of the rotor movement by an integer number of rotor poles, preferably by the integer number of rotor poles closest to the quotient MI (IG). If the stators are offset by an odd number of rotor poles, the polarity of the turns will be reversed by one of the two stators. The highest specific torques can be achieved with these design variants because the demagnetizing forces on the rotor poles are smallest. A smaller amplitude of the variable magnetic field in the rotor poles and a smaller proportion of the higher harmonic frequencies compared to the first variant enable smaller energy losses in the rotor. However, the bending loads on the rotor and the excitation forces on the rotor poles, which cause the rotor to vibrate, are large in comparison with the first variant, as is the phase coupling between the turns. In the case of stators with only one stator group of the individual phase, this variant has a large bending load on the rotor shaft. If the stator poles are evenly distributed, the number of rotor poles and the number of stator poles are preferably selected so that the opposing electromagnetic poles of the two stators are offset by half the layer spacing of the adjacent stator poles. In this case, the demagnetizing forces and the changing magnetic fields in the magnetic poles are lowest. In the case of stator designs with magnetically permeable pole cores, in which electromagnetic poles are distributed in sections at the same layer spacing as the rotor poles, the cogging torque is the lowest when the stator poles are mutually offset by 1 / (2F) of the average layer spacing of the adjacent rotor poles and the layer spacing of the rotor poles changes periodically by ± 1 / (8F) of the average layer spacing of the neighboring rotor poles. The housing of the motor is preferably made of metal. In doing so Aluminum and magnesium alloys preferred. Channels for liquid or gaseous coolant can be integrated in the motor housing, the channels preferably running parallel to surfaces through which the stators are connected to the housing. When the construction is made radially, the magnetic poles become radial

Direction oriented with respect to the rotor shaft. The part of the rotor that contains the magnetic poles is usually ring-shaped and is placed radially between the two stators. In the case of an axial design, the magnetic poles are oriented parallel to the rotor shaft. The part of the rotor that contains the magnetic poles is usually in the form of a disk. In the case of a linear design, the magnetic poles are oriented rectangular to the direction of the rotor movement. The configuration with two stators has a smaller proportion of the magnetic flux which parasitically closes between adjacent electromagnetic poles, compared to those which contain only one stator, which also leads to better utilization of the magnetic poles at higher torques. In general, two-stator

Constructions higher specific torques can be achieved than with one-way. A small difference between the number of rotor poles and the number of stator poles ensures that even with stators with magnetically permeable pole cores, the cogging torque and the torque unevenness can be kept small. Because of this and because of a good balance of the mechanical forces, the construction described runs very smoothly. The individual stator is subjected to less mechanical stress with a two-stator design than with a single-stator design. The bending loads on the rotor and the rotor shaft can be significantly smaller than in constructions with only one stator. Constructions with two stators ensure a significantly better one

Thermal permeability between the windings and the housing as constructions with similar capabilities that contain only one stator. Due to increased electrical resistance of the stator windings and smaller magnetic energy of the magnetic poles at higher temperatures, an increase in temperature in the motor has a negative effect on the motor capabilities. Thanks to better heat dissipation, the temperature of the motor can be kept lower in the described construction than in the conventional construction with a stator, which leads to lighter and more powerful motors which are still particularly suitable for direct drive of vehicles.

Claims

1. Synchronous electromechanical transducer, which has a radial, axial or linear construction, contains two stators and a rotor, which is located between the two stators and can be moved with respect to them; the rotor contains approximately uniformly distributed, alternately oriented magnetic poles, which are oriented approximately parallel to the direction, the rectangular area with the magnetic gap between the magnetic poles and the individual stator; the stator contains poles directed against the rotor and one or more magnetically permeable parts, through which the magnetic flux between adjacent poles closes on the side that does not adjoin the magnetic gap with the rotor; the stators are arranged with respect to the magnetic poles of the rotor so that the average phase of the turn of the individual electrical phase is approximately synchronous for both stators; in the case of rotary designs, the number of rotor poles which adjoin the magnetic gap with an individual stator is an even number, characterized in that the stator contains an equal number of identically arranged electromagnetic poles, each of at least two electrical phases, which are in contiguous groups of at least two electromagnetic poles are arranged, all of the electromagnetic poles of the individual groups belonging to the same electrical phase and the neighboring electromagnetic poles of the same group being electrically offset by 180 °; the number of rotor poles that adjoin the magnetic gap with an individual stator (M) differs from the number of electromagnetic poles of the stator (E) by the product between the number of stator groups whose electromagnet poles belong to the same electrical phase (G), and a natural number («) that is not a multiple of the electrical phase number (F), M = E ± nG; the neighboring electromagnetic poles that lead to different

Statorgmppen belong, are electrically offset by 180 ° + sgn (- E) (180 ° IF) n; the natural number n is preferably one; the number of stator groups of the individual stator, the electromagnetic poles of which belong to the same electrical phase, (G) is preferably one or two; the number of rotor poles that border the magnetic gap with an individual stator is the same for both stators; individual partial turns preferably contain the same number of olelectromagnetic poles of the first and second stator; If the stator contains more than one stator group of the individual phase in the rotary version, the total center of gravity of the layers is correct Electromagnetic poles, which belong to the same phase, preferably coincide with the rotor axis.

2. Synchronous electromechanical converter according to claim 1, characterized in that with at least one stator the electromagnetic poles are evenly distributed and the pole turns of the electromagnetic poles of individual stator groups are preferably connected in series.

3. Synchronous electromechanical converter according to claim 1, characterized in that in at least one stator, the number of magnetic poles bordering the magnetic gap with the stator is greater than the number of electromagnetic poles of the stator and the electromagnetic poles are distributed such that the layer spacing is adjacent

Electromagnetic poles of individual stator groups are equal to the average layer spacing of the neighboring rotor poles.

4. Synchronous electromechanical converter according to claim 1, characterized in that in at least one stator the number of magnetic poles bordering on the magnetic gap with the stator is greater than the number of electromagnetic poles of the stator and the natural number n according to Claim 1 is greater than one and the electromagnetic poles are more individual Stator group are evenly distributed so that the number of opposing rotor poles is one third of the rotor pole larger than the number of electromagnetic poles of the stator group.

5. Synchronous electromechanical converter according to Anspmch 1, characterized in that the number of poles and the pole distribution are identical in both stators.

6. Synchronous electromechanical converter according to Anspmch 5, characterized in that the stators are mutually offset in the direction of the rotor movement at most by GI (2E) of the layer spacing of the adjacent rotor poles; that individual partial winding preferably contains the same number of opposing electromagnetic poles of the first and second stator.

7. Synchronous electromechanical converter according to claim 5, characterized in that the stators are mutually offset in the direction of the rotor movement by an integer number of rotor poles, preferably by the integer number of rotor poles closest to the quotient MI (2G); that if the stators are offset by an odd number of rotor poles, the polarity of the turns is reversed by one of the two stators.

8. Synchronous electromechanical converter according to Anspmch 1, characterized in that the stator poles contain magnetically permeable poles, which are preferably in the vicinity of the magnetic gap at least in a direction which is approximately rectangular to the direction of the magnetic field in the magnetic gap, preferably in the direction parallel to the rotor movement; that the poles of the individual stator are preferably the same.

9. Synchronous electromechanical converter according to Anspmch 8, characterized in that there are magnetically permeable poles in at least one stator between the stator groups which do not belong to any electrical phase.

10. Synchronous electromechanical converter according to Anspmch 8 or 9, characterized in that the poles are made of magnetically permeable material with anisotropic magnetic properties, preferably of grain-oriented electrical sheet; that the direction with optimal magnetic properties preferably coincides with the direction of the magnetic field in the core shaft.

11. Synchronous electromechanical converter according to Anspmch 1, characterized in that the magnetic poles are inclined with respect to the electromagnetic poles in the direction of the rotor movement.

12. Synchronous electromechanical converter according to claim 1, characterized in that the layer spacing between adjacent magnetic poles changes periodically, the period preferably being the same as the number of rotor poles.

13. Synchronous electromechanical converter according to Anspmch 1, thereby characterized in that permanent magnets are used as magnetic poles, preferably made of materials based on rare earths; that the one with the

Magnet-occupied part of the circumference of the area that borders on the magnetic gap with an individual stator, is preferably seventy to eighty-five percent.

14. Synchronous electromechanical converter according to Anspmch 1, characterized in that the rotor, with the exception of the magnetic poles, contains no magnetically permeable or electrically conductive parts.

15. Synchronous electromechanical converter according to Anspmch 14, characterized in that the magnetic poles are connected to one another with polymers, preferably reinforced by fillers; that the part of the rotor which contains the magnetic poles is preferably connected to the shaft or to the parts which serve to connect to the shaft using the same material.

16. Synchronous electromechanical converter according to Anspmch 1, characterized in that at least one stator consists of preferably identical parts, which contain one or more poles and parts through which the magnetic flux closes between adjacent poles.

17. Synchronous electromechanical converter according to Anspmch 1, characterized in that the number of electrical phases is two or three.