DE102013223671B4 - ELECTRIC LATHE WITH INSIDE PERMANENT MAGNETS - Google Patents

Abstract

A rotary electric machine with internal permanent magnets (IPM) having a slots per phase per pole value of 2, comprising: a stator (11) adapted to receive stator windings in slots between stator teeth; a rotor (12) rotating in relation is rotatable on the stator (11) about a rotor axis and has an outer circumference (12a); several pairs of permanent magnets (16) in the rotor (12), the permanent magnets (16) of each pair being arranged in a "V" -shaped configuration which opens to the outer periphery (12a) and forms a magnetic pole; and orifices (17c) of low permeability, each of which replaces the predetermined area portion of one of the permanent magnets (16) which would generate magnetic flux lines directed such that magnetic flux lines emanating from the stator (11) near a longitudinal axis of one of the Magnetic poles would be extinguished if the permanent magnet (16) were located in the predetermined area, with a retaining projection for the permanent magnet (16) being provided at the opening (17c), one of which runs around a corner of the permanent magnet (16) and turns on the permanent magnet (16) clinging section and an adjoining straight end section, wherein the holding projection protrudes substantially perpendicularly from an edge of the opening (17c) into the opening (17c), the rotor (12) in the outer circumference (12a ) has a central regulating groove (21) and a pair of lateral regulating grooves (22) for the permanent magnets (16) of each pair, d The central regulating groove (21) and the lateral regulating grooves (22) are parallel to the rotor axis, the central regulating groove (21) being on the longitudinal axis, the lateral regulating grooves (22) being on the outer end faces of the permanent magnets (16) , wherein the rotor (12) has flux barriers which extend from the outer end sides of the permanent magnets (16) to the outer periphery (12a) of the rotor (12), the rotor (12) between the outer end inner surfaces (17b1) of the Flux barriers and the outer circumference (12a) of the rotor (12) has side bridges (30), each of the side bridges (30) connecting one side near the longitudinal axis and the other side near the adjacent transverse axis between the adjacent two magnetic poles, wherein the outer end inner surface (17b1) of each of the flux barriers on the rear side of the outer circumference (12a) of the rotor (12) has one end corner and another end corner, the outer end side ige inner surface (17b1) of each of the flow barriers has an intermediate point between the one and the other end corner, an inner surface portion (17b1d) extending on the side of the longitudinal axis between the one end corner and the intermediate point, and a transverse axis-side inner surface portion (17b1q) extending between the Intermediate point and the other end corner, an included angle θ8 between a reference line extending from the rotor axis to the intermediate point and the longitudinal axis satisfies a relationship expressed as 64.7 degrees ≦ θ8 (electrical angle) ≦ 74.2 degrees, the inner surface portion (17b1d) on the side of the longitudinal axis parallel to the outer circumferential surface (12a) of the rotor (12), with an included angle θ9 between the transverse axis-side inner surface section (17b1q) and an extension of the inner surface section on the side of the longitudinal axis towards the longitudinal axis as 0 degrees < θ9 (mechanical angle) ≦ 37.5 degrees Expressed rel unfulfilled.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority from those filed on November 29, 2012 Japanese patent application No. 2012-261569 , the entire contents of which are hereby incorporated by name for all purposes.

TECHNICAL AREA

The present invention relates to an internal lathe permanent magnet (IPM), and more particularly, to an electric IPM lathe with highly efficient operation in a drive mode.

GENERAL PRIOR ART

Electric lathes must meet different output characteristics to meet different requirements through devices to which they are attached. For example, if an electric lathe is to function as a traction motor in a hybrid electric vehicle (HEV: Hybrid Electric Vehicle, hybrid vehicle) as a power source that interacts with an internal combustion engine or in an electric vehicle (EV: Electric Vehicle, electric vehicle) the traction motor operates in a drive mode at a variable speed over a wide speed range and provides a sufficiently high torque at low speeds.

In the vehicles of the above type, an improvement in fuel economy requires an improvement in the energy conversion efficiency of each of the components including an electric lathe, and in the case of an in-vehicle electric lathe, in particular, an improvement in efficiency in a frequently used area. In addition, the on-vehicle electric lathe must have a more compact structure with a high energy density from the viewpoint of restrictions on the space for its assembly and from the viewpoint of miniaturization.

Incidentally, an electric lathe in HEVs or EVs in a normal drive mode generally works at low speeds under low load conditions. For this reason, strong permanent magnets tend to be used for high efficiency, since the magnetic moment contributes more to the generation of torque for the in-vehicle electric lathe than the reluctance moment, which varies with the amplitude of the currents through the stator windings.

This tendency is evidenced by the increasing use of permanent magnet type synchronous motors, which include a high remanence neodymium magnet embedded in a magnetic core and are referred to as IPM synchronous motors (synchronous motors with internal permanent magnets). In such an electric IPM lathe, it is proposed to embed several pairs of permanent magnets in a rotor in such a way that the permanent magnets of each pair are arranged in a “V” -shaped configuration that opens towards an outer circumference of the rotor a magnetic circuit is generated that is capable of actively using both the reluctance moment and the magnetic moment (see, for example, Patent Literature Example 1). It is also proposed in IPM electric lathes to provide flux barriers that protrude from both outer ends of the permanent magnets of each pair to an outer periphery of a rotor. It is also proposed to open such flow barriers in the outer circumference of the rotor (see patent literature example 2). It is also proposed to expand a space of each such flow barrier toward the outer periphery of the rotor (see Patent Literature Example 3).

STATE OF THE ART

• Patent Literature Example 1: JP 2006 - 254 629 A.
• Patent literature example 2: JP 2011- 4,480 A
• Patent Literature Example 3: JP 2012-29,524 A

The type of the permanently excited IPM rotor, which uses permanent magnetic fields and reluctance moments, is known to experts. See also the general summary of Meixner et al., Electrical Motor Vehicle Drive Technology, Inventor Activities 2011, German Patent and Trademark Office, October 2012, ISSN 2193-8180, pp. 51-52, which describes the field distributions in such rotors using the DE 696 29 419 T2 discussed.
The 8th of the US 2012/0 200 193 A1 shows a more conventional V-magnet rotor with smaller flux barriers at the top of the V .
The JP 2012 - 34 432 A or the US 2012/0 139 378 A1 or the US 2011/0 241 468 A1 shows an IPM rotor with V-magnets with enlarged flux barriers, to save magnetic material.
From the document Müller et al., Calculation of electrical machines, 6th edition, WILEY VCH Verlag, 2008, pp. 4, 5, 21, it can be seen how the number of holes in a stator is defined.
From Breimer et al., Fachkunde Elektrotechnik, Verlag Willing & Co., 7th edition, 1965, p. 202, common values for the number of uses and the number of poles of stators can be found, for. B. 48 and 2.
It is known to the professional world that permanent magnets cannot be magnetized further, i.e. behave differentially like air and not like iron, which is also evident from the field pictures, see also the Beckert document, calculation of magnetic circles with permanent magnets, script for non-electrical engineers, TU Bergakademie Freiberg, January 2008, p. 4, relative permeability of NdFeB and SmCo magnets.
It is known that disruptive harmonics can be compensated for by notches or depressions in the rotor which have to be accommodated at specific locations and with specific dimensions. Studer et al., Study of Cogging Torque in Permanent Magnet Machines, IEEE, Industry Applications Conference, Conference Record of the Thirty-Second IAS Annual Meeting, 1997 explicitly shows the calculation of the effect of notches on the rotor circumference of the magnets and also that Effects of modifying these notches.
Such is also in the JP 2004 - 328 956 A. , JP 2002 - 165 394 A. or US 2005/0 121 990 A1 shown.
The latter also shows notches on the edge and in the center of the pole of magnetic poles (cf. 2A and 2 B) , as well as a particularly large, "round" shaped notch in the center of the pole (cf. 13 ).
Some specialist publications show the efficient and quickly executable finite element calculations as long-established methods, such as Miller, Small motor drives expand their technology horizons, Power Engineering Journal, Sep. 1987, pp. 283-289, or Miller et al., Finite Elements applied to synchronous and switched reluctance motors, IEE Seminar Current trends in the use of finite elements (FE) in electromechanical analysis and design, IEE Savoy Place, 2000 , or Reece, Electrical machines and electromagnetics - computer aids to design, Power Engineering Journal, Nov. 1988, pp. 315-321.
This is also reflected in the teaching, e.g. B. in the study regulations of the University of Applied Sciences Dortmund, 1999, p. 7, compulsory catalog EU2, NBE numerical calculation of electrical machines, FEM finite element theory and application, or in the font Aschendorf, calculate first, then build, journal Konstruktionsprraxis, no 6th, 7th year, June 1996, pp. 16-19, or in Aschendorf, Amperehaltiger Röntgenblick, magazine KEM, 2001, pp. 56 ff.

Incidentally, in the latest electric lathes, permanent magnets containing rare earth elements such as Nd, Dy and Tb are increasingly used to increase magnetism and heat resistance, but rising prices caused by their rarity and the instability of their distribution cause one increasing need to improve efficiency while reducing the use amount of these rare earth elements.

However, since an electric lathe in HEVs and EVs operates in a normal drive mode at low speeds under low load conditions, even in IPM motors such as that described in Patent Literature Example 1, there is a tendency to increase the use amount of high magnetism permanent magnets to increase the magnetic Increase torque that contributes to low speed operation under low load conditions in drive mode. This approach moves away from fulfilling the task of reducing the use amount of rare earth elements.

Furthermore, since with regard to an electric IPM lathe described in Patent Literature Examples 2 and 3, since flux barriers on both outer end sides of the permanent magnets of each pair expand unnecessarily toward the outer periphery of a rotor, the magnetic reluctance between each of the flux barriers and the outer periphery increases to, causing the cogging torque to increase, thereby affecting the high quality rotation in a drive mode.

SUMMARY

Therefore, it is an object of the present invention to provide a low-cost, high-energy-density electric lathe that performs high-performance and high-quality operation in a drive mode while reducing the use amount of the permanent magnets.

• einen Stator, der dazu eingerichtet ist, Statorwicklungen in Schlitzen zwischen Statorzähnen aufzunehmen;
• einen Rotor, der in Bezug auf den Stator um eine Rotorachse drehbar ist und einen Außenumfang aufweist;
• mehrere Paare von Dauermagneten in dem Rotor, wobei die Dauermagnete jedes Paars in einer „V“-förmigen Gestaltung angeordnet sind, die sich zu dem Außenumfang hin öffnet, und einen Magnetpol bilden; und
• Öffnungen mit einer geringen Permeabilität, wobei jede davon den in einem vorherbestimmten Bereich befindlichen Abschnitt eines der Dauermagnete ersetzt, der so gerichtete Magnetflusslinien erzeugen würde, dass von dem Stator ausgehende Magnetflusslinien in der Nähe einer Längsachse (direkten Achse) eines der Magnetpole ausgelöscht würden, wenn sich der Dauermagnet in dem vorherbestimmten Bereich befinden würde,
• wobei an der Öffnung ein Haltevorsprung für den Dauermagneten vorgesehen ist, der einen um eine Ecke des Dauermagnets herum laufenden und sich an den Dauermagneten anschmiegenden Abschnitt und einen daran anschließenden geraden Endabschnitt umfasst,
• wobei der Haltevorsprung im Wesentlichen senkrecht von einer Berandung der Öffnung in die Öffnung hinein ragt,
• wobei der Rotor in dem Außenumfang für die Dauermagnete jedes Paars eine mittlere Regulierungsnut und ein Paar von seitlichen Regulierungsnuten aufweist,
• wobei die mittlere Regulierungsnut und die seitlichen Regulierungsnuten parallel zu der Rotorachse liegen,
• wobei sich die mittlere Regulierungsnut auf der Längsachse befindet,
• wobei sich die seitlichen Regulierungsnuten an den äußeren Endseiten der Dauermagnete befinden,
• wobei der Rotor Flussbarrieren aufweist, die sich von den äußeren Endseiten der Dauermagnete zu dem Außenumfang des Rotors hin erstrecken,
• wobei der Rotor Seitenbrücken zwischen den äußeren endseitigen Innenflächen der Flussbarrieren und dem Außenumfang des Rotors aufweist,
• wobei jede der Seitenbrücken eine Seite in der Nähe der Längsachse und die andere Seite in der Nähe der benachbarten Querachse (Quadraturachse) zwischen den benachbarten beiden Magnetpolen verbindet,
• wobei die äußere endseitige Innenfläche einer jeden der Flussbarrieren an der Rückseite des Außenumfangs des Rotors eine Endecke und eine andere Endecke aufweist,
• wobei die äußere endseitige Innenfläche einer jeden der Flussbarrieren einen Zwischenpunkt zwischen der einen und der anderen Endecke aufweist, wobei sich ein Innenflächenabschnitt auf Seiten der Längsachse zwischen der einen Endecke und dem Zwischenpunkt erstreckt, und sich ein Querachsenseitiger Innenflächenabschnitt zwischen dem Zwischenpunkt und der anderen Endecke erstreckt,
• wobei ein Einschlusswinkel θ8 zwischen einer Bezugslinie, die sich von der Rotorachse zu dem Zwischenpunkt erstreckt, und der Längsachse eine als
• 64,7 Grad ≦ θ8 (elektrischer Winkel) ≦ 74,2 Grad
• ausgedrückte Beziehung erfüllt, wobei der Innenflächenabschnitt auf Seiten der Längsachse parallel zu der äußeren Umfangsfläche des Rotors liegt,
• wobei ein Einschlusswinkel θ9 zwischen dem Querachsenseitigen Innenflächenabschnitt und einer Verlängerung des Innenflächenabschnitts auf Seiten der Längsachse zu der Längsachse hin eine als
• 0 Grad < θ9 (mechanischer Winkel) ≦ 37,5 Grad
• ausgedrückte Beziehung erfüllt.

According to a first aspect of the invention, there is provided an internal permanent magnet rotating machine (IPM) having a value of slots per phase per pole of 2, comprising:

• a stator configured to receive stator windings in slots between stator teeth;
• a rotor that is rotatable about a rotor axis with respect to the stator and has an outer periphery;
• a plurality of pairs of permanent magnets in the rotor, the permanent magnets of each pair being arranged in a “V” shape that opens to the outer periphery and forming a magnetic pole; and
• Openings with a low permeability, each of which replaces the portion of one of the permanent magnets located in a predetermined area, which would generate directed magnetic flux lines such that magnetic flux lines from the stator in the vicinity of a longitudinal axis (direct axis) of one of the magnetic poles would be extinguished if the permanent magnet would be in the predetermined range,
• wherein a holding projection for the permanent magnet is provided at the opening, which comprises a section running around a corner of the permanent magnet and adhering to the permanent magnet and a straight end section adjoining it,
• wherein the holding projection projects substantially perpendicularly from a boundary of the opening into the opening,
• the rotor in the outer circumference for the permanent magnets of each pair having a central regulating groove and a pair of lateral regulating grooves,
• the central regulation groove and the lateral regulation grooves are parallel to the rotor axis,
• with the central regulation groove on the longitudinal axis,
• the lateral regulation grooves are on the outer end sides of the permanent magnets,
• the rotor having flux barriers extending from the outer end sides of the permanent magnets to the outer periphery of the rotor,
• the rotor having side bridges between the outer end inner surfaces of the flow barriers and the outer circumference of the rotor,
• each of the side bridges connecting one side near the longitudinal axis and the other side near the adjacent transverse axis (quadrature axis) between the adjacent two magnetic poles,
• wherein the outer end inner surface of each of the flow barriers has an end corner and another end corner on the back of the outer periphery of the rotor,
• wherein the outer end inner surface of each of the flow barriers has an intermediate point between the one and the other end corner, an inner surface portion extends on the longitudinal axis side between the one end corner and the intermediate point, and a transverse axis inner surface portion extends between the intermediate point and the other end corner ,
• being an included angle θ8 between a reference line extending from the rotor axis to the intermediate point and the longitudinal axis as
• 64.7 degrees ≦ θ8 (electrical angle) ≦ 74.2 degrees
• expressed relationship, wherein the inner surface portion on the longitudinal axis side is parallel to the outer peripheral surface of the rotor,
• being an included angle θ9 between the transverse axis-side inner surface section and an extension of the inner surface section on the side of the longitudinal axis towards the longitudinal axis
• 0 degrees < θ9 (mechanical angle) ≦ 37.5 degrees
• expressed relationship fulfilled.

According to a second aspect of the invention, the angle of inclusion is satisfied θ8 in addition to the information described in the first aspect above, a as
64.9 degrees ≦ θ8 (electrical angle) ≦ 74.2 degrees
expressed relationship.

According to the first aspect of the present invention mentioned above, since an opening with a low permeability replaces the portion of one of the permanent magnets located in a predetermined area, which would generate directed magnetic flux lines such that magnetic flux lines emanating from the stator would be counteracted in the vicinity of a longitudinal axis of a magnetic pole (they would be extinguished), magnetic flux lines of the magnets in the vicinity of a longitudinal axis do not act against magnetic flux lines of the stator windings (do not extinguish them) and the passage of the magnetic flux lines through the predetermined area is restricted. Therefore, both the magnetic moment and the reluctance moment are effectively used by eliminating magnetic flux lines of the magnets that would render the stator magnetic flux lines near the longitudinal axis unnecessary, and the amount of use of the permanent magnets is reduced while obtaining a torque that is the same or larger than before replacing the portion of each of the permanent magnets with an opening.

In addition, replacing the portion of each of the permanent magnets with the opening improves the output power at high speeds because a reduction in the magnetic flux lines of the magnets causes a reduction in the induced voltage constants. In addition, saving weight causes a reduction in inertia.

A decrease in the magnetic flux lines of the magnets causes a decrease in the spatial harmonics causing magnetic distortion (magentostriction) due to a decrease in areas of weakness (a decrease in the amount of field weakening). This restricts the generation of heat by influencing the generation of eddy currents and restrains the demagnetization caused by a temperature change of the permanent magnets, which leads to a lower cost because the degree of heat resistance can be reduced.

In addition to reducing the magnetic flux near the longitudinal axis thanks to the opening mentioned above, since the central regulating grooves can regulate an increase in reluctance between the rotor and the stator teeth near the longitudinal axis, an increase in the interlinking magnetic flux of the stator windings can be restricted. Therefore, it is possible to prevent a drop in drive efficiency caused by an increase in torque ripple and iron loss.

In addition, the side regulation grooves can restrict harmonics that overlap the chained magnetic flux waveform by increasing the magnetic reluctance near the two outer ends of the permanent magnets of each pair arranged in a “V” shape. Therefore, it is possible to not only limit the cogging torque, but also prevent a drop in drive efficiency caused by an increase in torque ripple and iron loss.

In addition, a value of the slots per phase per pole is 2, and each of the flow barriers that cooperate with an outer periphery of the rotor to form side bridges is designed to have an inclusion angle θ8 (electrical angle), which is between the longitudinal axis and a reference line that extends from the rotor axis to an intermediate point on an outer end inner surface of the flow barrier between an inner surface portion on the longitudinal axis side and a transverse axis inner surface portion, in a range of 64.7 Degrees to 74.2 degrees (electrical degrees) so that the inner surface portion on the longitudinal axis side acts as a minimum bridge portion, and an inclusion angle θ9 (mechanical angle), which is between an extension of the inner surface portion on the longitudinal axis side and the transverse axis side inner surface portion, is in a range of 0 degrees to 37 degrees (mechanical degrees). This causes a reduction in the cogging torque, while the reduction in the torque is kept to a minimum.

As a result, an inexpensive rotary electric machine is realized which provides high quality operation with a high energy density in a drive mode.

Because the angle of inclusion θ8 , which is located between the longitudinal axis and the reference line extending from the rotor axis to the intermediate point, is narrowed to a range from 64.9 degrees to 74.2 degrees (electrical degrees) according to the above-mentioned second aspect, together with the cogging torque Torque ripple is further reduced, which causes a decrease in the electromagnetic vibrations of the stator cores resulting from the torque ripple and, together with the electromagnetic vibrations, a reduction in electromagnetic noise.

Furthermore, in addition to the above circumstances from the above-described point of view, the cogging torque and the torque ripple become by setting the inclusion angle θ8 (electrical angle), which is between the longitudinal axis and the reference line extending from the rotor axis to the intermediate point, in a range from 66 degrees to 68 degrees or from 70 degrees to 72 degrees, and setting the inclusion angle θ9 (Mechanical angle) which is between the extension of the inner surface portion on the longitudinal axis side and the transverse axis side inner surface portion is more effectively reduced to a range of 10 degrees to 27 degrees while keeping the torque reduction small.

In addition, the opening is widened considerably further in a radially inward direction towards the rotor axis than only the magnet opening for the permanent magnet extends, thereby avoiding the generation of saturation on the outer circumferential side of a magnetic pole by making a bypass that causes lines of magnetic flux which have entered the rotor from the stator along one of the two transverse axes for the magnetic pole to extend to the other transverse axis. Thereby, the reluctance torque originating from the magnetic stator flux is effectively used, causing an increase in the total average torque.

By expanding an additional space that extends toward the longitudinal axis toward the outer periphery of the rotor, this opening can properly regulate the direction of that portion of the magnetic flux that does not result in the extinction of magnetic flux lines of the stator windings, but does not do so effectively the magnetic flux lines of the stator windings can interact on the side of the longitudinal axis of the magnetic pole. Therefore, this further increases the total torque because the synthetic lines of magnetic flux formed by the combined action of the magnetic stator flux and the magnetic rotor flux are made to flow along a flux flow path that contributes to the efficient generation of torque.

With regard to the flux barriers that extend from both outer ends of the permanent magnets of each pair that forms a magnetic pole to the outer periphery of the rotor, an inclusion angle can be established θ6 (electrical angle) between the two outer ends of the permanent magnets of the pair are limited to a range of 144 degrees to 154.3 degrees, the 5th and 7th harmonics. In addition, by setting up an inclusion angle θ2 (mechanical angle) between the longitudinal axis and an outer surface of the permanent magnet on the side of the outer circumference to a range from 27.5 degrees to 72.5 degrees or to a range from 37.5 degrees to 82.5 degrees or to a range of 37, 5 degrees to 72.5 degrees, the torque is made high under a maximum load condition and under a low load condition, and the torque ripple and the 6th and the 12th harmonic torque components are restricted, thereby reducing electromagnetic vibrations and the electromagnetic noise.

Figure list

• 1 Fig. 4 is a top view of a rotor and stator of an IPM electric lathe embodying features of the invention.
• 2nd Fig. 3 is a diagrammatic view of a rotor embodying features of the invention, the stator having windings energized with electric current, but not including the permanent magnets and the lines of magnetic flux ( ψ _r ) are only generated by the energized stator windings, not shown, during operation in a drive mode under low load conditions.
• 3rd is a 2nd similar view, the stator has no current and the magnetic flux lines ( ψ _m ) from the North Poles (N) to the South Poles (S) only through the permanent magnets that are in magnet openings accommodated in the rotor are generated during operation in a drive mode under low load conditions.
• 4th Fig. 4 is a graph showing torque characteristics with respect to various degrees of current phases for a V-type IPM motor that includes a conventional rotor that is formed with an opening that is not large and located on the longitudinal axis side of each of the permanent magnets located;
• 5A Figure 3 is a diagrammatic view of the conventional rotor with the stator de-energized and the lines of magnetic flux ( ψ _m ) are only generated by the permanent magnets that are accommodated in magnet openings in the rotor.
• 5B 10 is an enlarged view of an area in the vicinity of each of the longitudinal axes of FIG 5A shown rotor, which has a vector field ( V _m ) indicates that it is only formed by the magnetic flux lines generated by the permanent magnets.
• 6A is a 5A Similar view, wherein the stator has stator windings energized with electric current, but the permanent magnets are not included and the magnetic flux lines ( ψ _r ) are only generated by the energized stator windings during operation in a drive mode under maximum load.
• 6B FIG. 12 is an enlarged view of an area near each of the longitudinal axes of FIG 6A shown rotor, which has a vector field ( V _r ) indicates that is formed only by the lines of magnetic flux generated by the energized stator windings.
• 7 FIG. 12 is a diagram of a model showing a relationship of the vector distribution through the permanent magnets of each pair that forms a magnetic pole with respect to the vector distribution through the energized stator windings in a region on the outer peripheral side of the magnetic pole of FIG 5A Conventional rotor shown during operation in a drive mode under maximum load.
• 8th FIG. 12 is a graph showing the correspondence of the torque with the phase of the input current with respect to the V-type IPM motor that is shown in FIG 5A rotor shown, shows.
• 9 is one 5A and 6A similar view, where the magnetic flux lines ( ψ _r ) are only generated by the energized stator windings during operation in a drive mode under low load.
• 10th is one 5A , 6A and 9 Similar view, but in addition to the synthetic magnetic flux lines ( ψ _p ) which by the combined effect of magnetic flux lines ( ψ _m ) generated by the permanent magnets and magnetic flux lines ( ψ _r ) that are generated by the energized stator windings, contains flux flow paths that are generated by the flux flow distribution of the synthetic magnetic flux lines ( ψ _p ) are defined in a drive mode under low load.
• 11 FIG. 12 is a graph showing the change in output torque and the rate of torque ripple reduction when each of the embedded permanent magnets is shortened in a rotor embodying features of the invention.
• 12th FIG. 5 is a diagram showing the change in the 5th order spatial harmonic when each of the embedded permanent magnets in the rotor embodying the features of the invention is shortened.
• 13 is a graph comparing percentages of torques generated when in the 5A , 6A and 9 The conventional rotor shown is used during low load drive mode operation with percentages of torque when the rotor embodying the features of the invention is used during low load drive mode operation.
• 14 is a 13 Similar diagram, but a comparison of percentages of torques that are generated when in the 5A , 6A and 9 The conventional rotor shown is used during operation in a drive mode under a maximum load, with percentages of torques when the rotor embodying the features of the invention is used during operation in a drive mode under a maximum load.
• 15 is a 2nd Similar view, wherein the stator has stator windings energized with electric current, but the permanent magnets are not included and the magnetic flux lines ( ψ _r ) are only generated by the energized stator windings, not shown, during operation in a drive mode under a maximum load.
• 16 is one 2nd and 15 similar view, but with synthetic magnetic flux lines ( ψ _p ), which are formed by the combined action of lines of magnetic flux generated by the permanent magnets and lines of magnetic flux generated by the energized stator windings, during operation in a drive mode under low loads.
• 17th is one 2nd , 15 and 16 similar view, but with synthetic magnetic flux lines ( ψ _p ) which are formed by the combined action of lines of magnetic flux generated by the permanent magnets and lines of magnetic flux generated by the energized stator windings during operation in a drive mode under a maximum load.
• 18th FIG. 12 is a diagrammatic view of a comparative structure of a rotor for comparison with the structure of FIG 17th shown embodiment, the synthetic magnetic flux lines ( ψ _p ) which are formed by the combined action of lines of magnetic flux generated by the permanent magnets and lines of magnetic flux generated by the energized stator windings during operation in a drive mode under a maximum load.
• 19th is a plot of the instantaneous torque in the average torque with respect to the electrical angle created by the construction A of the one in FIG 17th shown embodiment is generated, and that of the in 18th shown comparison structure B.
• 20 is a graph showing the percentage of each harmonic that the in 19th shown instantaneous torque waveform overlaid for everyone from the in 17th Structure A of the present embodiment shown in FIG 18th shown comparison structure B shows.
• 21 is a graph showing the percentage of each content of the tooth wave flux waveform for each of the in 17th Structure A of the present embodiment shown in FIG 18th shown comparison structure B shows.
• 22 FIG. 4 is a plot of torque with respect to FIG R2 / R1 as a parameter, where R2 the radial distance of that end wall of each of the river barriers 17c which is near the rotor axis, is from the rotor axis, and R1 is the outer radius of the rotor.
• 23 FIG. 4 is a plot of torque with respect to FIG R3 / R2 as a parameter, where R3 is the inside radius of the rotor, and R2 the radial distance of that end wall of each of the river barriers 17c which is near the rotor axis is from the rotor axis.
• 24th FIG. 12 is a diagrammatic view of a portion of a rotor embodying aspects of the invention near the corners of permanent magnets of each pair that are close to a longitudinal axis that includes a model that shows a relationship of vector distribution by permanent magnets with respect to FIG Vector distribution through energized windings during operation in a drive mode under a maximum load, wherein the rotor is designed with a large opening, which comprises an additional space in a magnet opening, which is formed due to a shortening of the length of the associated of the permanent magnets along the magnet opening, the large opening does not extend beyond the circumference of the permanent magnet towards the outer circumference of the rotor.
• 25th is a 18th similar view but including a rotor embodying aspects of the invention, the rotor being configured with a large opening that includes an additional space in a magnet opening formed due to a shortening of the length of the associated permanent magnet along the magnet opening, wherein the large opening extends from the additional space beyond the circumference of the permanent magnet to the outer circumference of the rotor.
• 26 FIG. 12 is a diagram that is enlarged and includes parameters that are used to determine shape dimensions of that portion of the opening that extends from the additional space beyond the perimeter of the associated permanent magnet to the outer perimeter of the rotor.
• 27 is a diagram of examples of design models when one in 26 shown parameter DL _d is changed.
• 28 is a graph showing the change in torque and the change in harmonic torque components when a ratio of DL _d to an outer radius R1 of the rotor is changed as a parameter.
• 29 is a graph showing the change in torque ripple when the ratio of DL _d to the outer radius R1 is changed.
• 30th FIG. 12 is a graph showing the change in torque and the change in harmonic torque components when a ratio θ1 / θ2 is changed as a parameter.
• 31 Fig. 12 is a graph showing the change in torque ripple when the ratio θ1 / θ2 is changed.
• 32 FIG. 4 is a plot of instantaneous torque in average torque versus electrical angle to compare the case of elongation of the flow barriers in the form of openings to the case where the flow barriers are not elongated.
• 33 is a graph showing the percentage of each harmonic torque component that the in 32 superimposed waveform of the instantaneous torque, shows.
• 34A is a 5A Similar view, the magnetic flux lines generated only by permanent magnets ( ψ _m ) contains, wherein the conventional rotor is designed with a not large opening, which is located on the long axis side of each permanent magnet, but is not designed with central grooves.
• 34B is a vector field for the synthetic magnetic flux lines, which are formed by the combined action of the magnetic flux lines generated by the permanent magnets and the magnetic flux lines generated by the energized stator windings, in the vicinity of a longitudinal axis when the V-type IPM motor, which is the conventional rotor which is designed with the small opening, which is located on the longitudinal axis side of each permanent magnet, operates in a drive mode under a maximum load, wherein the conventional rotor is not designed with central grooves.
• 35A Fig. 10 is a diagrammatic view indicating lines of magnetic flux generated only by the permanent magnets of a V-type IPM motor that includes a less preferred rotor that is designed with a large opening located on the longitudinal axis side of each permanent magnet , the less preferred rotor is not designed with middle grooves.
• 35B is a vector field for the synthetic magnetic flux lines formed by the combined action of the magnetic flux lines generated by the permanent magnets and the magnetic flux lines generated by the energized stator windings, near a longitudinal axis when the V-type IPM motor, the less preferred Rotor, which is designed with the large opening, which is located on the longitudinal axis side of each permanent magnet, operates in a drive mode under a maximum load, the less preferred rotor is not designed with central grooves.
• 36 FIG. 4 is a graph of the magnetic flux waveform of the tooth-chained flux with respect to the electrical angle through which FIG 34A shown conventional rotor, which is designed with the not large opening, which is located with each permanent magnet on the side of the longitudinal axis, wherein the conventional rotor is designed with no central grooves, with the in 35A shown less preferred rotor, which is designed with the large opening, which is located with each permanent magnet on the side of the longitudinal axis, the less preferred rotor is not designed with central grooves.
• 37 FIG. 12 is a graph showing the percentage of the content of each of the harmonics contained in a magnetic flux waveform chained to a stator tooth after a Fourier transform of the one in FIG 36 flow waveforms shown.
• 38 is a vector field for the synthetic magnetic flux lines formed by the combined action of the magnetic flux lines generated by the permanent magnets and the magnetic flux lines generated by the energized stator windings, near a longitudinal axis when a V-type IPM motor that includes a rotor , which embodies aspects of the invention, operates in a drive mode under maximum load, the rotor being designed with central grooves in addition to a large opening which is located on the longitudinal axis side of each permanent magnet.
• 39 10 is a plot of torque versus electrical angle to match the present embodiment with that in FIG 35A to compare the structure shown, the less preferred rotor not being designed with central grooves.
• 40 FIG. 12 is a diagram showing the degree of each harmonic torque component, that of the torque waveform obtained after a Fourier transform of the one in FIG 39 is shown, is superimposed.
• 41 Fig. 4 is an enlarged fragmentary view of a magnetic pole of the rotor showing parameters used to determine the shape dimensions of each of the central grooves.
• 42 is a graph showing the change in torque ripple when in 41 shown ratio used for the shape dimensions of the middle groove R4 to the outer radius R1 is changed as a parameter.
• 43 Fig. 14 is a diagram showing phase voltage waveforms and a conductor voltage waveform when an outer arc angle θ _a is used as a parameter.
• 44 10 is a plot of torque versus electrical angle to match the present embodiment with that in FIG 35A The structure shown is compared, the less preferred rotor not having central grooves, the torque waveforms being shown during operation in a drive mode under low loads.
• 45 FIG. 12 is a diagram showing the degree of each harmonic torque component, the torque waveform obtained after a Fourier transform of the one in FIG 44 given waveforms is superimposed.
• 46 Fig. 10 is a diagram of a structure made without any side grooves, showing a positional relationship of a magnetic pole to stator teeth.
• 47 FIG. 14 is an illustration of a split magnetic flux waveform generated when the in FIG 46 shown construction, which is carried out without any lateral grooves, operates under a no-load condition.
• 48 FIG. 14 is an illustration of a split magnetic flux waveform generated when the in FIG 46 shown construction, which is carried out without any lateral grooves, operates under a maximum load condition.
• 49 Fig. 4 is an enlarged fragmentary view of a magnetic pole of the rotor showing parameters used to determine the shape dimensions of each of the side grooves to be formed in the outer periphery of the rotor.
• 50 is a graph showing the changes in the average torque, harmonic torque components and torque ripple when the ratio θ5 (inside inclusion angle or inside included angle from the longitudinal axis) / θ4 (outside inclusion angle or outside included angle from the longitudinal axis) at the mold dimensions for each of the in 49 shown lateral grooves is changed as a parameter during operation under a maximum load condition.
• 51 FIG. 10 is a graph showing changes in the average torque, harmonic torque components and torque ripple when the ratio θ5 (inside inclusion angle from the longitudinal axis) / θ4 (outside inclusion angle from the longitudinal axis) in the mold dimensions for each of the in 49 shown lateral grooves is changed as a parameter during operation under low load conditions.
• 52 is a graph showing the changes in the average torque and the torque ripple when the ratio RG (groove depth) / AG (air gap width) in the mold dimensions for each of the in 49 shown lateral grooves is changed as a parameter during operation under a maximum load condition.
• 53 FIG. 12 is a graph showing split magnetic flux waveforms, one generated by the side-groove structure and the other by the side-groove structure, during operation under a no-load condition to compare the amplitudes of the superimposed harmonics.
• 54 FIG. 12 is a graph showing torque waveforms, one generated by the side-groove structure and the other by the structure without side grooves, during operation under a maximum load condition to compare the amplitude of the torque ripples.
• 55 FIG. 12 is a graph showing torque waveforms, one generated by the side-groove structure and the other by the side-groove structure, during low load operation to compare the amplitude of the torque ripple.
• 56 FIG. 12 is a diagram showing cogging torque waveforms, one generated by the side-groove structure and the other by the structure without side grooves, during operation under a no-load condition to check a reduction in cogging torque.
• 57 Fig. 3 is an enlarged fragmentary view of a magnetic pole of the rotor showing a pole opening angle θ6 and a magnet opening angle θ2 shows.
• 58 Figure 12 is a diagram of an approximate waveform of the split magnetic flux chained to a tooth.
• 59 FIG. 12 is a graph illustrating a relationship between the approximate waveform of split magnetic flux chained with a tooth, the pole opening angle and the magnet opening angle.
• 60 FIG. 12 is a diagram showing an actual waveform of the split magnetic flux chained with a tooth in overlap with its ideal waveform.
• 61 is a graph showing changes in average torque, harmonic torque components and torque ripple when the magnet opening angle θ2 is changed as a parameter during operation under a maximum load condition.
• 62 is a graph showing changes in average torque, harmonic torque components and torque ripple when the magnet opening angle θ2 is changed as a parameter during operation under low load conditions.
• 63 Fig. 3 is an enlarged fragmentary view of a magnetic pole of the rotor, showing the shape of each of the side bridges.
• 64 Fig. 3 is an enlarged view of an area near a side bridge that has a vector field ( V _m ) indicates that the magnetic flux lines generated by the permanent magnets only form during operation in a drive mode without a loading condition.
• 65A FIG. 14 is an illustration of the magnetic flux density waveform generated in an air gap between a rotor and a stator during operation in a drive mode with no load condition.
• 65B is a fragmentary enlarged view of 65A which is a representation of an increase range of the in 65A indicates the waveform of the magnetic flux density shown.
• 66 Fig. 3 is an enlarged view of an area near a side bridge that has a vector field ( V _r ) indicates that it is only formed during operation in a drive mode under a maximum load condition by the lines of magnetic flux generated by the stator windings.
• 67 FIG. 12 is an outline diagram of the results of the mechanical strength analysis indicating locations where the induced Von Mises voltage becomes large during operation of the V-type IPM motor in a drive mode at high speeds.
• 68 FIG. 4 is an illustration of the cogging torque that changes when a bending point on an outer end inner surface of each of the outer flow barriers is changed.
• 69 FIG. 4 is a representation of the torque and torque ripple that change when the bend point on the outer end inside surface of the outside flow barrier is changed.
• 70 FIG. 4 is an illustration of the torque and torque ripple that change when the amount of bending in the outer end inner surface of the outer flow barrier is changed.

DETAILED DESCRIPTION

An embodiment (s) of the present invention will be described with reference to the accompanying drawings. 1 to 70 show an embodiment of an electrical IPM lathe according to the present invention. In the following description of the preferred embodiment, a rotor rotates in a direction for illustrative purposes only, for example, that it rotates counterclockwise (CCW: counterclockwise) with respect to a stator.

In 1 includes an electric lathe or a motor 10th a stator 11 , which is in the form of a generally cylindrical configuration, and a rotor 12th by this stator 11 is surrounded, is rotatable on an axis of rotation or a rotor axis, and fixed to a drive shaft 13 , which is arranged coaxially with the axis of rotation, is coupled. The electric lathe 10th provides a performance that is adapted to specifications that are required for a power source of a hybrid vehicle (HEV) or an electric vehicle (EV), such as an internal combustion engine is required for a vehicle as a power source, or is adapted to specifications that are required for a built-in one Power source in each of the drive wheels of a vehicle are required.

The stator 11 is with several stator teeth 15 executed which extend in radial directions from the rotor axis in such a way that an inner circumference 15a of the stator 11 and an outer circumference 12a of the rotor 12th face each other through an intermediate space G between them. The stator 11 is wrapped with three-phase windings, each of which is a distributed winding for each phase (not shown) to form stator windings that are capable of generating a magnetic flux that communicates with the rotor 12th interacts to produce a rotor torque.

The rotor 12th is designed as a rotor of an IPM motor (motor with internal permanent magnets); and there are several sets of permanent magnets in it 12th embedded, with each set a pair of permanent magnets per pole 16 has, which are arranged in a "V" -shaped configuration, which extends to the outer circumference 12a opens. The rotor is for the permanent magnets of each pair 12th with a set of openings 17th executed, which are arranged in a "V" -shaped design, which extends to the outer circumference 12a opens to the permanent magnets 16 , each having the same rectangular cross-sectional profile along its length and extending in the axial direction along the rotor axis, by allowing their corners 16a in the set of openings 17th be used.

The openings 17th Each set arranged in a "V" shape includes magnetic openings 17a that are designed to be the permanent magnets 16 of the corresponding pair and include and openings 17b and 17c that over each of the permanent magnets 16 are arranged and separated from each other in the direction of its width and serve as flow barriers to prevent the magnetic flux from being around the permanent magnet 16 turns (hereinafter referred to as "river barriers" 17b and 17c ) designated. Every set of openings 17th , which are arranged in a "V" -shaped design, has a central bridge 20 on that between the openings 17c which are between the permanent magnets 16 each pair are located in a radial direction from the rotor axis to connect the inner and outer edges defining the opening to the permanent magnets against the centrifugal force generated when the rotor is turned 12th spins at a high speed to hold in place. Side bridges 30th that have the same function as the middle bridge 20 will be described later.

With this electric lathe 10th form openings, each between two adjacent stator teeth 15 of the stator 11 are slots 18th , in which stator windings are inserted, around coil groups around the stator teeth 15 to build. On the other hand, each of the eight sets of permanent magnets 16 on the rotor 12th to the corresponding six of the stator teeth 15 of the stator 11 directed. In short, this is an electric lathe 10th designed so that each pole is held by a pair of permanent magnets 16 on the rotor 12th is formed to the adjacent six slots 18th of the stator 11 is directed. That means the electric lathe 10th is designed as a three-phase IPM motor, in which the two facing sides of a pair of magnets in every second magnetic pole have the north poles, while the two facing sides of a pair of magnets in the neighboring magnetic pole have the south poles, and a 48-slot -Stator is wrapped in distributed windings to form coils, each under each phase having an electrical degree coil spacing of five stator teeth, which results in 8 magnetic poles ( 4th Pairs of magnetic poles) are formed. In other words, the electric lathe 10th designed as an IPM-type structure in which (value q of the slots per pole and phase) = {(number of slots) / (number of poles)} / (number of phases) = 2.

This allows the rotor 12th works in a drive mode by the stator windings that are in the slots 18th of the stator 11 are energized to create lines of magnetic flux that extend from the stator teeth 15 directed radially inward into the opposite rotor 12th extend. In this case, the electric lathe 10th (Stator 11 and rotor 12th ) a reluctance moment that seeks to shorten the flux flow path, with a magnetic moment derived from the attraction and repulsion forces between the permanent magnets 16 comes, combined to produce a composite torque. Therefore, electrical energy generated by a current that is fed into the stator windings is from a drive shaft that is related to the stator 11 with the rotor 12th is rotatable, taken as mechanical energy.

Everyone from the stator 11 and the rotor 12th includes multiple layers arranged in a stacked relationship. Each of the layers is formed from an electrical steel such as silicon steel. The layers are made using fasteners 19th stacked to an appropriate axial thickness for a desired output torque.

The electric lathe 10th has a coil group for each phase, which is in slots 18th is accommodated in a distributed winding, so that as in 2nd illustrated for each set of Stator teeth 15 that lead to a pair of permanent magnets 16 , which form a magnetic pole, are directed, a flux flow path generated by the energized stator windings a flux flow path (of magnetic flux lines ψ _r , which are generated only by the energized stator windings) defined between the slots 18th through the stator 11 extends radially inward after it is close to the outer circumference of the stator 11 , ie, behind the set of stator teeth 15 has moved in a circumferential direction to in the rotor 15 to penetrate and run through it. The permanent magnets 16 each pair are in the magnet openings 17a a set of openings arranged in a "V" shape 17th that run along the flux flow path of the magnetic flux lines ψ _r which are generated only by the energized stator windings are formed, in other words are formed so that they build the lines of magnetic flux ψ _r not prevent being added.

The through permanent magnets 16 generated flux flow paths (the magnetic flux lines ψ _m , which are only produced by the permanent magnets), which are produced by a like in 3rd illustrated flow flow distribution are defined, extend only perpendicularly from the north poles (N-poles) on one side of the permanent magnets 16 each pair that forms a magnetic pole and penetrate perpendicularly into the south poles (S poles) on opposite sides of the permanent magnets 16 a. In particular, each of the river flow paths runs after entering the stator 11 from the corresponding stator teeth 15 near the outer circumference of the stator 11 in a circumferential direction.

In the IPM structure, in which the permanent magnets 16 each pair in the rotor 12th are embedded and arranged in a "V" shape, a direction of the flux lines formed by each of the magnetic poles becomes, that is, a central axis between the permanent magnets 16 each pair arranged in a "V" shape is referred to as a longitudinal axis (d-axis) and becomes a central axis, which shows electrical and magnetic orthogonality with respect to the longitudinal axis, between adjacent permanent magnets 16 between adjacent magnetic poles referred to as the transverse axis (q axis). In the rotor 12th extend radially inner openings 17c located on the side of the longitudinal axis of each set of openings 17th , which are arranged in a "V" shape, are located radially inward of the rotor axis, and are designed to function as flow barriers 12c to execute. Suitable shape dimensions of the river barriers 17c each set of openings 17th arranged in a "V" shape will be described later.

With this electric lathe 10th this enables flux lines generated by the stator windings ψ _r that are in radially inward directions from the stator teeth 15 in the rotor 12th have penetrated close to the inner circumference (the rotor axis) further in such a way that they do not enter the radially outward area of the openings 17th each set, which are arranged in a "V" shape, penetrate before going to the stator teeth 15 return as in 2nd is illustrated. In a word is the electric lathe 10th designed as a V-type IPM motor with a rotor 12th comprises, which is designed in the vicinity of the longitudinal axes with openings.

The electric lathe also includes 10th to prevent heavy overlapping of the river lines ψ _r generated by the stator windings and stator teeth 15 , which correspond to the longitudinal axes, in radially inward directions in the rotor 12th penetrate through the 5th and 7th spatial harmonic middle grooves (middle regulation grooves) 21 that in the outer circumference of the rotor 12th are formed and each parallel to the inner circumference 15a one of the corresponding stator teeth 15 (in a direction along the rotor axis). Suitable mold dimensions for each of the middle grooves 21 will be described later.

The electric lathe also includes 10th one pair of lateral grooves (magnetic adjustment grooves) per magnetic pole 22 that are in the vicinity of the radially outer ends of the permanent magnets of each pair forming a magnetic pole in the outer circumference 12a of the rotor are formed to mitigate the pulsation of the engine torque over the entire operating range in a drive mode by reducing the cogging torque under no load and the torque ripple under low load conditions and a maximum load while minimizing a reduction in torque. Suitable shape dimensions for each of the side grooves 22 will be described later.

ausgedrückt, wobei

• P_p die Anzahl der Polpaare ist, ψ_m die Flusslinien von Magneten sind, die mit dem Stator (Statorzähnen 15) verkettet sind,
• i_d der Strom der Längsachse ist, i_q der Strom der Querachse ist,
• L_d die Induktivität der Längsachse ist, und L_q die Induktivität der Querachse ist.

With the electric lathe 10th with the IPM structure, with permanent magnets 16 in a "V" shape in the rotor 12th are embedded, the torque T is given by the following equation (1) $$\text{T}={\text{P}}_{\text{p}}\left\{{\mathrm{\psi }}_{\text{m}}{\text{i}}_{\text{q}}+\left({\text{L}}_{\text{d}}-{\text{L}}_{\text{q}}\right){\text{i}}_{\text{q}}{\text{i}}_{\text{q}}\right\}$$

expressed where

• P _{p is} the number of pole pairs, ψ _m are the flux lines of magnets that are connected to the stator (stator teeth 15 ) are chained,
• i _{d is} the current of the longitudinal axis, i _q the current of the transverse axis is
• L _d is the inductance of the longitudinal axis, and L _q is the inductance of the transverse axis.

As in 4th is shown by an operation with the current phase, in which the sum of the magnetic moment T _m and the reluctance moment T _r reached the maximum value, a highly efficient operation with a high torque of the electric lathe 10th provided.

With reference to 5A to 6B are in the case of a comparison rotor 12A according to the related technology, the river barriers 17c (please refer 1 to 3rd ) in the form of openings located on the longitudinal axis side through flow barriers 17d replaced. The river barriers 17d are generally with flow barriers in terms of shape dimensions 17b which are located on the radially outer sides of the openings arranged in a “V” shape 17th of each sentence are identical. With regard to the comparison rotor 12A are the flux flow paths through the permanent magnets 16 through an in 5A illustrated flow flow distribution defined. The magnetic flux lines ψ _m Vectors created by the magnets define vectors V _m that are represented by a vector field in 5B have specified directions. In addition there are lines of magnetic flux ψ _r by energized stator windings, which are in slots 18th are generated, generated by an in 6A illustrated flow flow distribution and they define vectors V _r that are represented by a vector field in 6B have specified directions.

The electric lathe that the rotor 12A of the above type is operated by advancing a current phase angle (phase angle of the current) to generate a high torque with a high efficiency in the drive mode under a maximum load. Under this condition, the rotor 12A operated according to the related technology in a state in which magnetic flux lines ψ _m of the magnets and lines of magnetic flux ψ _r of the stator windings in a small area A1 (please refer 6B) that differs from the set of openings arranged in a “V” shape 17th located radially outward and near the longitudinal axis, generate opposite fields, so that the reluctance moment T _r the magnetic moment T _m wipes out, as illustrated by the vector fields illustrated in 5B and 6B is shown. In short, this is a small area A1 as in 7 shown an interaction area in the magnetic flux lines ψ _m of the magnets and lines of magnetic flux ψr of the stator windings interact with each other at an induced angle that is equal to or greater than 90 degrees, so that the magnetic flux lines ψ _r of the stator windings are wasted or weakened because they are those lines of magnetic flux ψ _m counteract the magnets (extinguish them) from areas B near the longitudinal axis of the permanent magnets 16 of each pair, which are adjacent to the small area A that extends radially outward from the set of openings arranged in a “V” shape 17th located.

For this reason, it can be said that due to the fact that it is the area B of the permanent magnet 16 , which are in the vicinity of the longitudinal axis, fail to make any active contribution to the generation of torque T, the amount of use of the permanent magnets is possible 16 to decrease in itself by the volume of the areas B, near the longitudinal axis, of the permanent magnets 16 is reduced while maintaining a saliency ratio in the magnetic circuit as high as the previous leg ratio.

Now, the torque T expressed by the aforementioned equation (1) becomes smaller with a decrease in the use amount of the permanent magnets 16 as high as the previous torque that occurred prior to reducing the amount of permanent magnets used 16 had been generated by the reluctance moment T _r is increased. This reluctance moment T _r is increased by a difference between the inductance L _d the longitudinal axis and the inductance L _q the transverse axis is increased, that is, by increasing a ratio of thigh.

Therefore, the torque T according to the present embodiment of the rotor 12th as high as the previous torque held by each of the areas B, near the longitudinal axis, of the permanent magnets 16 is replaced with an opening with a low magnetic permeability (referred to as a "restricted area") to increase a ratio of the limb while the amount of use of the permanent magnets 16 is reduced. The reluctance moment is viewed from a different angle T _r increased by that portion of the magnetic flux lines ψ _r of the stator windings by acting against the magnetic flux lines ψ _m by the permanent magnets that are located near the longitudinal axis Extend areas B, has been used wastefully, is effectively used, so the torque T despite the reduction in the amount of use of the permanent magnets 16 remains unchanged.

wobei β der Stromphasenwinkel ist, und I_a die Amplitude des Phasenstroms ist.The torque T can also be expressed by the following equation (2). The ratio of the magnetic moment T _m is under low load conditions, under which the amplitude of the current I _a is decreased, high. As in 8th shown the current phase angle β approaches, at which the torque is the maximum value, the more zero, the lower the amplitude of the current I _a is. The illustrated waveforms i, ii, iii, iv and v in 8th are characteristic curves each showing the relationship between the torque and the current phase angle at one of different amplitudes of the current I _a (i) , I _a (ii) , I _a (iii) , I _a (iv) and I _a (v) show, where the amplitudes of the currents have the relationship of the following inequality equation: i <ii <iii <iv <v. Therefore, despite the fact that the ratio of (the dependence on) the magnetic moment T _m is naturally high during operation under low load conditions, it is desirable to create a magnetic circuit that uses this magnetic moment effectively T _m maximized. $$\text{T}={\text{P}}_{\text{p}}\left\{{\mathrm{\psi }}_{\text{m}}{\text{I.}}_{\text{a}}\text{cos}\mathrm{\beta \; +}\frac{1}{\mathrm{2nd}}\left({\text{L}}_{\text{d}}-{\text{L}}_{\text{q}}\right){\text{I.}}_{\text{a}}{}^{\mathrm{2nd}}\text{sin2}\mathrm{\beta }\right\}$$

where β is the current phase angle, and I _a is the amplitude of the phase current.

As in 9 shown takes the number of lines of magnetic flux ψ _r the stator windings at the rotor 12A according to the related technology on each of the transverse axes between the adjacent two magnetic poles (between the permanent magnets 16 of the adjacent two different magnetic poles), since the current phase angle β is close to zero due to the operation under low load conditions with a small amplitude of the current. It is therefore ideal if a magnetic circuit is in 10th shown river flow paths MP1 and MP2 as stretches of the merged river lines ψ _p by the combined effect of the magnetic flux lines of the magnets ψ _m and the magnetic flux lines mentioned above ψ _r the stator windings are formed. This will be an active use of the reluctance moment T _r allow, because the merged river lines ψ _p the inductance L _q the transverse axis along each transverse axis by distributing the transverse axis flux flow path (magnetic flux lines through the transverse axis) that extends along the transverse axis (without inducing any saturation).

The river flow path MP1 turns after entering the rotor 12A in the interpolar section between the adjacent two magnetic poles via the air gap G from one of the stator teeth 15 in a chaining relationship in one direction to the neighboring one of a pair of permanent magnets 16 which form a preceding one of the two magnetic poles with respect to the direction of rotation of the rotor (in 10th seen to the left), and runs from its side near the inner circumference of the rotor 12A through it. The river flow path MP1 then crosses the outer peripheral region A2 of the magnetic pole and returns via the air gap G to another one of the stator teeth 15 back.

The river flow path MP2 after turning in the same way as the river flow path MP1 in the interpolar section in the rotor 12A has penetrated in a circumferential direction to the removed one of the permanent magnets 16 which form the preceding one of the two magnetic poles with respect to the direction of rotation of the rotor, and extends from the side thereof in the vicinity of the inner circumference of the rotor 12A through it. The river flow path MP2 then crosses the outer peripheral region A2 of the magnetic pole and returns via the air gap G to another one of the stator teeth 15 back.

If permanent magnets 16 of each pair are moved inward toward the rotor axis by removing portions that are inward from their distal two ends (the radially outer ends of the pole), it becomes this flow flow path MP1 and MP2 not succeed the entire outer peripheral area A2 to use each pole effectively because enlarged flux barriers, adjacent to the most distant ends of the pair's permanent magnets, concentrate in the vicinity of the center of the pole and make it difficult for the flux flow paths, particularly through the right half of the outer peripheral region A2 to extend.

If the permanent magnets 16 on the other hand, by removing portions inward from their closest ends (the radially inner ends of the magnetic pole) near the central axis of the permanent magnets, large flux barriers occur near the central axis of the permanent magnets, which causes the river flow paths to be scattered so that they pass through both Side portions of the magnetic pole extend, which is why the lines of magnetic flux flow evenly through the outer peripheral region A2 of the magnetic pole extend by effectively covering the entire outer peripheral area A2 use including his right half. With this structure, a river flow path connects MP3 the neighboring magnetic poles from the north pole (N pole) of a permanent magnet 16 the subsequent of the adjacent two magnetic poles to the south pole (S pole) of the adjacent permanent magnet 16 the previous one of the adjacent two magnetic poles with respect to the direction of rotation of the rotor after passing through the permanent magnet 16 of the subsequent magnetic pole - from the outside near the outer circumference of the rotor to the inside near the inner circumference of the rotor. In a way that the river flow path MP1 is similar, the river flow path extends MP3 through the outer peripheral area A2 of the foregoing magnetic pole with respect to the direction of rotation of the rotor, causing the effect of decentralization of the magnetic flux lines to become high.

Because of this, it is convenient if a rotor 12th for the structure for embedding the permanent magnets 16 each pair that forms a magnetic pole uses a design in which the permanent magnets 16 of the pair are moved outward to their most distant two ends (the radially outermost ends of the magnetic pole), while the "V" shape of the permanent magnets 16 is maintained to the distribution of the magnetic flux lines ψ _r which is the reluctance moment T _r generate, not to interfere. It is also favorable to use a design in which between the permanent magnets 16 of the pair (the radially inner ends of the magnetic pole) flow barriers 17c are formed to limit the short circuit path of the magnetic flux lines. In addition, it is advantageous to use a design in which there is a central groove on each of the longitudinal axes 21 in the outer peripheral surface of the rotor 12th located to generate saturation of the magnetic flux lines ψ _r of the stator windings by the stator teeth 15 of the stator 11 come to restrict or, in other words, the lines of magnetic flux ψ _r of stator windings. By using these designs, the rotor 12th the reluctance moment T _r Use actively by scattering the cross-axis flux paths (magnetic flux lines) around the inductance L _q to increase the transverse axis.

The optimal value for a length in the attached drawings W _pm (Width) of each of the permanent magnets 16 is compared to the case where the longitudinal length W _pm is not extended, determined as standard.

In particular, it is determined by a relationship δ , which is given by calculating the following equation (3), being a number of poles P is fixed, an outer radius R1 that is from the axis of the rotor 12th extends to the outer periphery, is fixed, and the length W _pm of every permanent magnet 16 of a pair disposed on an outer end portion of a magnetic pole is made variable, that is, the position of each of the inner ends of the permanent magnets 16 of the pair is changed. The determining factors of the ratio are the change in the value per unit of the torque T under the condition of the maximum load in relation to the ratio δ and the change in the rate of decrease in the fluctuation of this torque T, ie, the torque ripple, with respect to the ratio δ given after a magnetic field analysis and as in the representation of 11 shown graphically. For example, in the "per unit" system, 1.0 [per unit] means that the size corresponds to a base unit. $$\mathrm{\delta \; =}\left(\text{P}\times {\text{W}}_{\text{pm}}\right)/\text{<figure-callout id="1" label="R" filenames="DE102013223671B4\_0035.png,DE102013223671B4\_0036.png" state="{{state}}">R</figure-callout>}1$$

In 11 represents the relationship δ of 1.84 (δ = 1.84) represents the case where each of the permanent magnets 16 has a shape dimension with a length W _pm of the permanent magnet 16 is not shortened (ie, a reduction in the amount of the permanent magnet material is 0%). It can be seen that when the mold dimension meets the ratio of δ = 1.38 (ie when the reduction in the amount of permanent magnet material is 24.7%), the torque T generated corresponds to the torque generated by the rotor 12A related technology with permanent magnets 16 whose length W _pm is not shortened, is generated (ie, the torque T is 1.0 [per unit]). With the permanent magnets 16 then when the ratio δ 1.38 (δ = 1.38) produces the same torque in operation even at slow speeds under low load conditions that are commonly used.

In 11 becomes the rotor 12A the related technology used for comparison. With this comparison rotor 12A defines each set of openings arranged in a "V" shape 17th at its radially outer and inner ends, outer and inner flow barriers 17b and 17d of the same size. In contrast, the rotor divides and separates 12th the magnetic flux lines according to the present embodiment ψ _r of the stator windings thanks to the provision of the flux barriers 17c and a medium groove 21 Per Magnetic pole effective in two. This causes the rotor to effectively apply a reluctance torque T _r generated and the torque ripple is limited, while the torque T at the ratio δ = 1.84, at which the length W _pm each of the permanent magnets 16 is not shortened, that is, the permanent magnets 16 in terms of length W _pm that of the rotor 12A are the same, is improved. In other words, shows 11 Changes in torque and torque ripple with different ratio values δ if the length W _pm each of the permanent magnets 16 in the construction of the rotor 16 is shortened according to the present embodiment. It is believed that over the range of the ratio δ from 1.84 to near 1.38 no noticeable change in torque T occurs, ie, torque T remains essentially 1.0 [per unit] when the length W _pm each of the permanent magnets 16 in the construction of the rotor 12A related technology is shortened.

In electric lathes, the rotation of a rotor occurs due to a magnetic distortion resulting from a field weakening when an induced voltage (i.e., a reverse voltage) is generated, the amplitude of which is variable depending on the amount of use of the embedded permanent magnets Spatial harmonics. The harmonics cause an increase in iron loss since the 5th, 7th, 11th and 13th harmonics cause the generation of torque ripple. The generation of the 5th spatial harmonic is as in 12th shown graphically per unit in relation to the ratio δ shown. Out 12th it can be seen that the lower the ratio, the more the generation of the 5th spatial harmonic is reduced δ from 1.75 it becomes (δ = 1.75). In this case, the use amount of the permanent magnets is reduced by 4.7% or more, and the generation of heat is reduced because, thanks to an improvement in efficiency resulting from a reduction in iron loss due to a reduction in the harmonics caused by magnetic distortion, Eddy currents in the permanent magnets 16 be limited.

It follows that the rotor 12th according to the present embodiment to reduce the amount of the permanent magnet material used to manufacture the permanent magnets 16 is used while the output of the torque is as high as that of the rotor 12A the related technology is held, that ratio is favorable δ by shortening the length W _pm of each of the permanent magnets is set to about 1.38, that is, δ ≒ 1.38 (reduction in the amount of the permanent magnet material by 24.7%). This also reduces the torque ripple. In short, the shape dimensions of each of the permanent magnets 16 be chosen so that they are suitable for a desired property of the output of the torque T and the torque ripple, so that the ratio δ falls in a range from δ = 1.38 (a reduction in the amount of permanent magnet material of 24.7%) to δ = 1.75 (a reduction in the amount of permanent magnet material of 4.7%).

A magnetic analysis of two different IPM motors capable of producing the same torque, the length W _pm the permanent magnet 16 each pair arranged in a "V" shape is shortened in a motor to leave openings near each longitudinal axis (d-axis) to provide mold dimensions where the ratio δ = 1, 38 while the permanent magnets 16 each pair arranged in a "V" shape in which other motor are not shortened shows that as in 13 and 14 shown the electric lathe 10th generates essentially the same torque T when the ratio of the reluctance torque T _r to the magnetic moment T _m is changed. The V-shaped IPM motor with openings near each longitudinal axis is designed to provide flow barriers 17c large openings located near each longitudinal axis occupy, while the bare V-shaped IPM motor is designed to provide flow barriers 17d occupy small openings located near each longitudinal axis.

13 shows the relationship between the moment T _m and the moment T _r during operation in the low load area, while 14 the relationship between the moment T _m and the moment T _r shows during operation in the maximum load range. How 13 and 14 show, takes the ratio of the reluctance moment T _r in the case of the V-shaped type IPM motor with large openings near each longitudinal axis in both load ranges with a decrease in the ratio of the magnetic moment T _m by shortening the length of each permanent magnet 16 is caused to. In a small area A1 who is like in 6B and 7 shown near the outer periphery of each pole are formed by forming the river barriers 17c that occupy large openings instead of permanent magnets 16 near the longitudinal axis and also forming a middle groove 21 the magnetic flux lines ψ _m of the magnets that line the magnetic flux ψ _r counteracting the stator windings, reduced. This leads to an increase in inductance L _q the transverse axis (q axis), which causes a difference between the inductance L _q the transverse axis (q axis) and the inductance L _d the longitudinal axis (or the leg ratio) greater than that (or the leg ratio) of the IPM motor from the V-shaped Type with non-shortened permanent magnets is what enables the electric lathe 10th through effective use of the reluctance moment T _m generates an equivalent torque.

As by the river flow distribution in 15 shown this construction allows the electric lathe 10th some of the magnetic flux lines ψ _r of the stator windings that are in the small area A1 concentrated radially outward from the permanent magnets of each pair forming a magnetic pole, effectively from the flux flow path M _r 1 through the small area located radially outward A1 extends into the flow flow path M _r 2 which separates around the radially inward side of the openings located near the longitudinal axis 17c of a set of openings 17th , which are arranged in a "V" shape, runs. As a result, the magnetic lathe is reduced 10th the magnetic interaction between magnetic flux lines ψ _{m of} the magnets and magnetic flux lines ψ _r of the stator windings (d-axis, q-axis), around a local magnetic saturation on the preceding side with respect to the direction of rotation of the radially outward small area A1 to avoid the magnetic pole, which can effectively contribute to the generation of torque T.

Therefore, it runs through the river flow distribution in 16 illustrates the majority of synthetic magnetic flux lines ψ _p by the combined effect of the magnetic flux lines ψ _m of the magnets and the magnetic flux lines ψ _r of the stator windings are formed by flux flow paths MPO, which are defined by the permanent magnets 16 each pair extend when the electric lathe 10th works in a drive mode under low loads while the synthetic magnetic flux lines ψ _p as by the river flow distribution of 17th illustrated in a river flow path MP1 and a river flow path MP2 share when operating in drive mode under maximum load. As a result, the electric lathe realized 10th the avoidance of local magnetic saturation along with a reduction in magnetic interaction to effectively produce the same or a higher degree of torque T than the V-shaped type IPM motor with non-shortened permanent magnets, while reducing the amount of permanent magnet material the permanent magnet 16 is achieved. The magnetic flux lines make during operation in a drive mode under low load conditions ψ _m of the magnets compared to the lines of magnetic flux ψ _r of the stator windings in the synthetic magnetic flux lines ψ _p a high percentage.

If the permanent magnets 16 for example have such shape dimensions that the ratio δ = 1.44 and the amount of permanent magnet material is reduced by 23% and due to flux barriers 17c is replaced with a low magnetic permeability (reduction of the magnetic flux lines ψ _m of the magnets), it makes a reduction in the back emf constant of about 13.4%, which is accompanied by a reduction in inertia, for the electric lathe 10th possible that their output power increases at high rotational speeds. In addition, a reduction in the harmonics that cause magnetic distortion reduces the heat and iron loss in the permanent magnets 16 due to eddy currents, and it limits electromagnetic noise.

In other words, how easy it is from the illustrated river flow lines in 18th is evident when, for example, each of the river barriers 17e not in a radially inward direction to the axis of the rotor 12th extends, difficult, the synthetic magnetic flux ψ _p to a sufficient extent to divide into two currents, creating local magnetic saturation, which is the small area located on the outer peripheral side of each rotor pole A1 with respect to the direction of rotation of the rotor 12th (in 18th seen the left side), cannot be avoided.

If the in 17th shown, with the river barriers 17c provided structure A according to the present embodiment using the amount of the output torque and its fluctuations (torque ripple) with that in FIG 18th shown comparison structure B, with the flow barriers 17e is compared, is off 19th which shows the output torque characteristics in the maximum load condition, it can be seen that the structure A is superior to the structure B in that the output torque increases by about 6% and the torque ripple falls, thereby providing high quality operation in the drive mode. In 19th are based on a calculation of the average torque using the in 18th Structure B shown as the base unit size, the instantaneous output torque of the in 17th Construction A shown and that of in 18th shown structure B in relation to the angle of rotation (the electrical angle) in quantities which are expressed “per unit”.

In order to compare the harmonic torque components superimposed on the output torque of the structure A with those on the output torque of the structure B, the in 19th processed waveforms by a Fourier series expansion, which changes as in 20 shown Results show that especially the 12th . and the 24th . Harmonic torque components that superimpose the output torque are considerably lower in structure A than in structure B. With the structure A according to the present embodiment, this suppresses the occurrence of jerky acceleration when accelerating up a slope, and considerably reduces the level of electromagnetic noise, particularly by the 12th . harmonic torque component is significantly reduced. In 20 the percentages (%) of the harmonic torque components contained in the output torques of structures A and B are illustrated.

To the content of the 11 . and the 13 . Comparing spatial harmonics in structure A with that in structure B, the waveform of the magnetic flux is linked to one of the stator teeth 15 processed through the gap G by a Fourier series expansion, whereby as in 21 Results shown show that the content of the 11 . and the 13 . Spatial harmonics in structure A is considerably lower than in structure B. In 21 is the content of the spatial harmonics after normalizing a basic waveform component of the magnetic flux chained to a tooth in structure A as the base unit and that in structure B as the base unit “per unit”.

Incidentally, it can be seen that in the electric lathe 10th the torque ripple, in the case of three phases, by spatial harmonics, which superimpose one flux waveform per phase per magnetic pole, and time harmonics, which are contained in phase currents, in electrical degrees for the component of the 6th order (where f is a natural number of 1, 2, 3, ... is) is generated.

$$\begin{array}{c}\mathrm{\tau }\left(\text{t}\right)=\text{P}\left(\text{t}\right)/{\mathrm{\omega }}_{\text{m}}\\ =\left[{\text{E}}_{\text{u}}\left(\text{t}\right){\text{I}}_{\text{u}}\left(\text{t}\right)+{\text{E}}_{\text{v}}\left(\text{t}\right){\text{I}}_{\text{v}}\left(\text{t}\right)+{\text{E}}_{\text{w}}{\text{I}}_{\text{w}}\left(\text{t}\right)\right]\end{array}$$

ausgedrückt werden,
wobei ω_m die Winkelgeschwindigkeit ist, E_u(t), E_v(t) und E_w(t) die induzierten elektromotorischen Kräfte der Phase U, der Phase V bzw. der Phase W sind, und I_u(t), I_v(t) und I_w(t) der Strom der Phase U, der Phase V bzw. der Phase W ist.If the reason for the generation of the torque ripple is described below, the three-phase output power (the electric current) P (t) and the torque τ _t by the formulas (4) and (5) as $$P\left(t\right)={\text{E}}_{\text{u}}\left(\text{t}\right){\text{I.}}_{\text{u}}\left(\text{t}\right)+{\text{E}}_{\text{v}}\left(\text{t}\right){\text{I.}}_{\text{v}}\left(\text{t}\right)+{\text{E}}_{\text{w}}\left(\text{t}\right){\text{I.}}_{\text{w}}\left(\text{t}\right)$$

$$\begin{array}{c}\mathrm{\tau }\left(\text{t}\right)=\text{P}\left(\text{t}\right)/{\mathrm{\omega }}_{\text{m}}\\ =\left[{\text{E}}_{\text{u}}\left(\text{t}\right){\text{I.}}_{\text{u}}\left(\text{t}\right)+{\text{E}}_{\text{v}}\left(\text{t}\right){\text{I.}}_{\text{v}}\left(\text{t}\right)+{\text{E}}_{\text{w}}{\text{I.}}_{\text{w}}\left(\text{t}\right)\right]\end{array}$$

be expressed
in which ω _m the angular velocity is E _u (t) , E _v (t) and E _w (t) the induced electromotive forces of the phase U , the phase V or the phase W are and I _u (t) , I _v (t) and I _w (t) the current of the phase U , the phase V or the phase W is.

$$\begin{array}{l}{\mathrm{\tau }}_{\text{u}}\left(\text{t}\right)=\\ \frac{1}{{\mathrm{\omega }}_{\text{m}}}\left[{\displaystyle \sum _{\text{n}=1}^{\text{n}}{\displaystyle \sum _{\text{m}=1}^{\text{m}}{\text{E}}_{\text{m}}}{\text{I}}_{\text{m}}\left\{-\frac{1}{2}\left(\text{cos}\left(\left(\text{n}+\text{m}\right)\mathrm{\theta +}\text{n}{\mathrm{\alpha }}_{\text{n}}+\text{m}{\mathrm{\beta }}_{\text{m}}\right)-\text{cos}(\left(\text{n}-\text{m}\right)\mathrm{\theta +}\text{n}{\mathrm{\alpha }}_{\text{n}}-\text{m}{\mathrm{\beta }}_{\text{m}}\right)\right\}}\right]\end{array}$$

The three-phase torque is the sum of the torque of the phase U , the torque of the phase V and the torque of the phase W ; and if the stream I _u (t) the phase U Expressed by formula (6), in which "m" is the order of the harmonic component contained in the current and "n" is the order of the harmonic component contained in the voltage, the torque τ _u (t) of the phase U can be expressed by the following formula (7): $${\text{I.}}_{\text{u}}\left(\text{t}\right)={\displaystyle \sum _{\text{m}=1}^{\text{m}}{\text{I.}}_{\text{m}}\text{sin m}\cdot \left(\mathrm{\theta }+{\mathrm{\beta }}_{\text{m}}\right)}$$

$$\begin{array}{l}{\mathrm{\tau }}_{\text{u}}\left(\text{t}\right)=\\ \frac{1}{{\mathrm{\omega }}_{\text{m}}}\left[{\displaystyle \sum _{\text{n}=1}^{\text{n}}{\displaystyle \sum _{\text{m}=1}^{\text{m}}{\text{E}}_{\text{m}}}{\text{I.}}_{\text{m}}\left\{-\frac{1}{\mathrm{2nd}}\left(\text{cos}\left(\left(\text{n}+\text{m}\right)\mathrm{\theta \; +}\text{n}{\mathrm{\alpha }}_{\text{n}}+\text{m}{\mathrm{\beta }}_{\text{m}}\right)-\text{cos}(\left(\text{n}-\text{m}\right)\mathrm{\theta \; +}\text{n}{\mathrm{\alpha }}_{\text{n}}-\text{m}{\mathrm{\beta }}_{\text{m}}\right)\right\}}\right]\end{array}$$

wobei 6f = n ± m (f ist eine natürliche Zahl) ist, s = nα_n + mβ_m ist, und t = nα_n - mβ_m ist.Both the phase current I (t) and the phase voltage E (t) are symmetrical waves, which is why it is necessary for m and n to be odd. In terms of the torques other than that of the phase U - the torque of the phase V and the torque of the phase W - The phase shift of the torque of the phase V from the induced voltage E _u (t) the phase U and the stream I _u (t) the phase U and the phase shift of the torque of the phase W of them + 2π / 3 (rad.) or -2π / 3 (rad.). The resulting torque is given by deleting the links except links with a coefficient of "6" and can be expressed by the following formula (8). $$\mathrm{\tau }\left(\text{t}\right)=\frac{1}{{\mathrm{\omega }}_{\text{m}}}\left[{\displaystyle \sum _{\text{n}=1}^{\text{n}}{\displaystyle \sum _{\text{m}=1}^{\text{m}}{\text{E}}_{\text{m}}}{\text{I.}}_{\text{m}}}\left\{-\frac{1}{\mathrm{2nd}}\mathrm{3rd}\text{cos}\left(6\text{f}\mathrm{\theta \; +}\text{s}\right)-\mathrm{3rd}\text{cos}\left(6\text{f}\mathrm{\theta \; +}\text{t}\right)\right\}\}\right]$$

where 6f = n ± m (f is a natural number), s = nα _n + mβ _m , and t = nα _n - mβ _m .

Since an induction voltage is a time derivative of a magnetic flux, additional harmonic components of the same order as those contained in an induction voltage in each phase also occur in a magnetic flux per pole per phase. It follows that in a three-phase motor the 6th torque harmonic appears as torque ripple if n, ie the number of the order of the harmonics contained in the magnetic flux (the induction voltage) and m, ie the number of the order of the time harmonics, contained in the phase current are combined to give 6f.

Because with this electric lathe 10th Torque ripple occurs when the equation 6f = n ± m is satisfied, when a magnetic flux per pole per phase contains the nth harmonic and a phase current contains the mth harmonic, for example, arises in response to a combination of, for example , the overlapping 11th and 13th spatial harmonics (n = 11, 13) and the fundamental wave (m = 1) of a phase current the 12th harmonic torque.

With this electric lathe 10th is the position of an end wall on the side near the rotor axis that each of the flow barriers 17c the one in the rotor 12th openings formed 17th each set arranged in a "V" shape is enlarged in a radially inward direction, so determined that its enlarged size is optimized toward the rotor axis while the shape dimensions of each of the permanent magnets 16 be preserved in such a way that the condition under which the relationship δ 1.44 is ( δ = 1.44).

Referring again to 1 is the construction of this rotor 12th by evaluating those in the 22 and 23 Torque properties shown changing a radial distance R2 that end wall of the river barriers 17c , which is near the rotor axis, from the rotor axis in the ratios R2 / R1 and R3 / R2 used as parameters, where R1 the outer radius is to an outer circumference of the rotor, and R3 is the inner radius to its inner circumference. Because the permeability (the ease with which a magnetic flux is generated) of stacked electrical steel plates depends on the Von Mises stress, which results from the compressive stress caused by the press fit to connect them to the drive shaft, with which the electrical steel plates are pressed together , results, deteriorates, the shape dimensions of the rotor are determined in terms of the torque properties, taking into account the von Mises stress. In the 22 and 23 are quantities of the torque that is generated in the state of the maximum load, expressed as “per unit” quantities, which refer to the in the 18th Relate to the defined basis shown in the example of a comparative construction.

Out 22 it can be seen that a torque equal to or greater than the torque generated by structure B is generated when the ratio R2 / R1 falls in a range A of 0.56 to 0.84. The radial distance is preferred R2 the end wall of the river barrier 17c selected from the rotor axis from a range B of 0.565 near one turning point to 0.75 near another turning point. In particular, it is selected from a range C from 0.59 to approximately 0.63, in which an increase in torque of approximately 5% is expected.

Next is out 23 it can be seen that a torque that is equal to or greater than the torque generated by structure B is generated when the ratio R3 / R2 falls in a range from 0.54 to 0.82. The radial distance is preferred R2 the end wall of the river barrier 17c selected from the rotor axis from a range B of 0.60 near one turning point to 0.81 near another turning point. In particular, it is selected from a range C of 0.72 to 0.77, in which an increase in torque of about 5% is expected.

This enables the size of the flow barriers 17c is determined in such a way that a sufficient width for the in 17th river flow path shown MP2 is ensured without being in the river flow path MP2 any magnetic saturation is caused.

Referring to an in 24th shown rotor 12B are, as mentioned above, even if the length is in a longitudinal direction (width) W _pm each of the permanent magnets 16 is optimally designed, near the corners 16a the permanent magnet 16 each pair close to the long axis of that Electromagnetic flux ψ _r acquired vectors V _r by the magnetic flux ψ _m acquired vectors V _m counteract. In particular, stay close to the corners 16a the permanent magnet 16 close to the longitudinal axis there is a state of a relationship of opposing magnetic fields, in which the magnetic flux lines differ ψ _r the stator windings, which run through a flux flow path that is at the innermost of the small area radially outside of each magnetic pole with respect to the rotor axis A1 stretches, obtained vectors V _r Vectors V _m of magnetic flux lines ψ _m counter the magnets in the opposite direction with an induced angle equal to or greater than 90 degrees (counteract them) and compensate (cancel) them. For this reason, when building this rotor 12B the magnetic flux lines ψ _r the stator windings, which are close to the corners located near the longitudinal axis 16a walk past, wasted or weakened as they go against lines of magnetic flux ψ _m the magnets work (wipe them out).

It follows that in the electric lathe 10th (the rotor 12th ) who (in) 25th is shown, river barriers located near the longitudinal axis 17c are formed in openings which are also directed outward to the outer periphery 12a of the rotor 12th extend there. This will provide a structure, the lines of magnetic flux ψ _r of the stator windings and magnetic flux lines ψ _m The magnet is used effectively by the flux flow path over which the magnetic flux lines pass ψ _m the magnet near the corners 16a moving close to the longitudinal axis is allowed to proceed in such a way that vectors V _r by magnetic flux lines ψ _r the stator windings were obtained near the corners 16a with an induced angle equal to or less than 90 degrees with vectors V _m by magnetic flux lines ψ _m the magnets have been obtained, interact.

Be more precise with this electric lathe 10th the mold dimensions 1 and 2nd that portion of each of the openings that the flow barriers 17c the openings arranged in a “V” shape 17th form each set that faces outward to the outer perimeter 12a of the rotor extends so as to optimize the section while the shape dimensions of each of the permanent magnets 16 are set so that the relationship of the ratio δ = 1.44 is preserved.

As in 26 a separation distance is shown first DLd from a point Y at which the longitudinal axis and an extension plane of an outer peripheral end face (a flat shape) 17cu of the flow barrier 17c intersect each other, to a point X at which the longitudinal axis and the outer circumference 12a of the rotor 12th intersect each other as a shape dimension 1 for the river barriers 17c of the rotor 1 chosen. The optimal range for this separation distance DL _d is done after evaluating the average torque, the harmonic torque components and the torque ripple that are obtained when a ratio of the distance DLd to the outer radius R1 , DLd / R1 , is used as a parameter. In other words, the distance (separation distance) DLd from the outer circumference 12a to an end of the outer peripheral end surface (a flat shape) 17cu on the longitudinal axis side as a shape dimension 1 for the river barrier 17c so determined that optimal properties are obtained, the saturation of the magnetic flux, the flux flow path MP1 which defines the outer peripheral area A2 each magnetic pole crosses, be prevented.

As in 27 the outer peripheral end faces 17cu of the flow barriers are shown 17c in a radially outward direction so to the outer periphery 12a stretched as if from the outer circumference 12a of the rotor 12th over an area of with DLd / R1 = 0.194 designated starting position, at which each of them is the same plane with the corresponding one of the expansion planes of the wall surfaces (the outer surfaces of the permanent magnets 16 ) 17au, that on the outer peripheral side of the magnet openings 17a the openings arranged in a “V” shape 17th of each sentence is located, communicates with the DLd / R1 = 0.086 designated end position would be drawn. It can be seen that, if this is the case, the torque properties as in FIG 28 and 29 shown change. 28 shows the average torque during operation in a drive mode under the maximum load condition per unit using the case of DLd / R1 = 0.194 as the base unit. Additionally shows 28 as harmonic torque components, the overlapping 6th and 12th components (electrical angle) in percent and the rate of change of the torque as torque ripple.

In terms of shape dimensions 1 for the river barriers 17c of the rotor 12th can out 28 can be seen that the amount of torque generated when DLd / R1 falls in a range A of 0.098 to 0.194, becomes equal to or larger than that generated by the structure in which that on the outer peripheral side of the magnet openings 17a the openings arranged in a “V” shape 17th each set of wall surfaces 17au are only extended. With regard to this shape dimension 1 the 12th harmonic torque component is further reduced if DLd / R1 falls in a range B from about 0.11 to about 0.194, and in particular the maximum torque is generated when DLd / R1 in ranges from about 0.12 to about 0.14. How out 29 it can be seen that the torque ripple reaches a minimum if DLd / R for this shape dimension 1 to provide the best point design BP1 Is 0.139.

In addition, as in 26 shown an inclination angle α of the outer peripheral end surface 17cu of the flow barrier 17c to the corresponding one of the wall surfaces 17au, which is on the outer peripheral side of the magnet openings 17a the openings arranged in a “V” shape 17th each set are located as the shape dimension 2nd for the river barriers 17c of the rotor 12th chosen.

Under the use of DLd / R1 = 0.139 as a basis, this angle of inclination α determines a ratio θ1 / θ2, where θ1 through the longitudinal axis and the outer peripheral end surface 17cu of the flow barrier 17c inclusion angle formed, and θ2 that by the longitudinal axis and the associated one of the wall surfaces 17au, that on the outer peripheral side of the magnet openings 17a the openings arranged in a “V” shape 17th each set is located, is formed inclusion angle. The optimal range for this ratio θ1 / θ2 is determined after evaluating the average torque, the harmonic torque components and the torque ripple obtained when used as a parameter, as in 30th and 31 is shown. In other words, the angle of inclination α becomes the shape dimension 2nd for the river barriers 17c so determined that optimal properties will be obtained which will produce such a flow flow path that the electromagnetic flow is prevented ψ _r the magnetic flux ψ _m near that corner 16a of each of the permanent magnets, which are close to the longitudinal axis of the on the circumferential side of each rotor pole of the rotor 12th located small area A1 is suppressed. 30th Figure 12 shows the average torque during operation in a drive mode under the maximum load condition per unit using the case of 1 / θ2 = 1.7 as the base unit. Additionally shows 30th the overlapping 6th and 12th components as percentages and shows as harmonic torque components 31 the rate of change of torque as torque ripple. Because the angle θ2 Often referred to as the magnet opening angle, the angle θ1 referred to as the flux barrier opening angle.

In terms of shape dimensions 2nd for the river barriers 17c of the rotor 12th is over 30th it can be seen that the amount of torque generated becomes large and the 12th harmonic torque component is reduced when θ1 / θ2 falls in a range D from about 1.2 to about 1.7. In terms of shape dimensions 2nd is also out 31 it can be seen that the torque reaches a maximum and the torque ripple reaches a minimum if θ1 / θ2 is preferably 1.52 in order to provide a best point configuration BP2.

If both mold dimensions 1 and 2nd for each of the river barriers 17c is taken into account on the condition that the ratio DLd / R1 falls in the range A from 0.098 to 0.194, the angle θ1 under this condition by dividing it by the angle θ2 that the angle θ1 shifts, given, and suitable torque characteristics are provided when the ratio θ1 / θ2 is selected from a range of 1.0 to 2.13. Additionally, on condition that the ratio DLd / R1 falls in the range B from 0.11 to 0.194, more suitable torque properties are provided when the ratio θ1 / θ2 is selected from a range from 1.0 to 2.02.

Furthermore, under the condition that - after taking into account the two mold dimensions 1 and 2nd for each of the river barriers 17c - an optimization with DLd = 0.139 and θ1 / θ2 = 1.5 is carried out, as in 32 shown compared to that in 24th Illustrated comparative example increases the average torque by about 1.8% and suppresses the torque ripple. As in 33 shown reduce these mold dimensions 1 and 2nd the 12th . and the 24th harmonic torque component compared to that in 24th illustrated comparative construction example considerably. This suppresses the occurrence of a jerky acceleration when driving up a slope and considerably reduces the degree of electromagnetic noise, particularly by significantly reducing the 12th harmonic torque component.

Now with the following reference to the in 34A shown rotor 12A the permanent magnets 16 Each pair that forms a magnetic pole, even in the vicinity of a longitudinal axis between them, are created by the permanent magnets 16 in the radially outward area A2 of the magnetic pole has many lines of magnetic flux ψ _m generated. On the other hand, with regard to an in 35A shown rotor 12C who is not with a medium groove 21 per magnetic pole because it is close to a longitudinal axis between the permanent magnets of each pair with flux barriers 17c is executed, each having the shape of an opening, the property of the straight course of the permanent magnets 16 generated Lines of magnetic flux ψ _m worsen. In other words, the flux density is the magnetic flux lines ψ _m low in the vicinity of the longitudinal axis. Since the magnetic resistance in the vicinity of the longitudinal axis is low, the inductance for a flux flow path ψ _q crossing the longitudinal axis is therefore high. As a result, leads in the rotor 12C a superimposition of the outer circumference 12a concatenating magnetic flux due to harmonics caused by the occurrence of a difference in density of the magnetic flux due to an increased torque ripple and an increased iron loss cause a decrease in efficiency.

Referring to an in 34B The flux vector field shown, which is formed during operation under maximum load, is the density of the interlinking magnetic flux from the opposite stator tooth 15D which is the flux flow path of the magnetic flux lines ψ _r corresponds to the magnet, near the longitudinal axis of the rotor 12A not high. On the other hand, with reference to the in 35B shown flux vector field, which is formed during operation under maximum load, the density of the interlinking magnetic flux in the vicinity of the longitudinal axis of the rotor 12C higher than that of the magnetic flux in the stator tooth 15D remains, which causes an increased inflow of magnetic flux.

This is from the representations in 36 resulting from a comparison of the rotor 12C (River barriers 17c , no middle groove 21 ) with the rotor 12A (River barriers 17d , no middle groove 21 ) with regard to the waveform of the interlinking magnetic flux from a stator tooth, that is, magnetic flux lines that cover the air gap G from a stator tooth 15D cross here, visible, the rotor 12C so less preferred than the rotor 12A is when the magnetic flux lines can cross the air gap G more easily at a point “P” where they are influenced by the vicinity of the longitudinal axis, which causes an increased tendency to overlap by harmonics. As from the in 37 results shown after processing the in 36 shown waveforms by Fourier series expansion, contains those by the rotor 12C generated magnetic flux waveform considerably more harmonic in 5th and 7th than in the magnetic flux waveform generated by the rotor 12A is generated, is the case.

Hence the rotor 12th on the electric lathe 12th on its outer circumference 12a with medium grooves 21 executed, which are each on one of the longitudinal axes to the magnetic resistance on the common with the inner circumference of the stator tooth 15 to regulate the air gap G formed. How through an in 38 The flow vector field shown, which is formed during operation under maximum load, is limited to that with such middle grooves 21 executed rotor 12th an increase in the inflow of magnetic flux from stator teeth 15 , which come to lie opposite the rotor one after the other, near the longitudinal axis.

As from the representations in 39 resulting from a comparison of those made by this rotor 12th (with medium grooves 21 ) generated torque waveform with that by the rotor 12C (without middle grooves 21 ) using the rotor 12C as the base unit - 1.0 (per unit) - can be seen, the rotor is reduced 12th with medium grooves 21 the amplitude of the torque waveform more so as to limit the torque ripple than is the case with the rotor 12C the case is. As from the in 40 results shown after processing the in 39 shown waveforms by Fourier series expansion, the 6th, 12th, 18th and 24th harmonic torque components are those by the rotor 12th with medium grooves 21 generated waveform significantly reduced. In 39 is the torque waveform of the instantaneous torque using the average torque generated by the rotor 12C is generated as a base unit - 1.0 (base unit).

Thus, in the electric lathe 10th the appropriate shape dimensions of each of the middle grooves 21 determined on the basis of torque properties such as the torque ripple mentioned above.

With regard to the middle groove 21 the appropriate mold dimensions after evaluating the in 42 torque ripple shown by changing one in 41 shown radial distance R4 of a groove bottom 21a the middle groove 21 from the rotor axis in the ratio R4 / R1 , which is used as a parameter, where R1 the outer radius to the outer circumference of the rotor 12th is determined.

First, in terms of the depth of the middle groove 21 using the shape dimension for the rotor without middle grooves 21 as standard (R4 / R1 = 1.0) the depth is made with the following shape dimensions,
0.98 ≦ R4 / R1 <1.0,
to allow a reduction in the torque ripple generated during maximum load operation.

Then in terms of the middle groove 21 of the rotor 12th for their shape dimensions a determination of their relative relationship to the stator teeth 15 of the stator 11 required, being defined by an outer arc angle θa for the middle groove 21 around the axis of the rotor 12th and an inner arc angle θb for the groove bottom 21a is possible.

With continued reference to the rotor 12th the phase voltages and the line voltage are as shown in 43 indicated at points by points F and apex sections V are affected when the outside angle θa for the middle groove 21 is changed as a parameter.

In particular, a period changes between G1 and G3 the voltage waveform of the phase U on the positional relationship between the stator 11 and the rotor 12th forth depending on the width of the outer arc angle θa for the middle groove 21 . The voltage waveform of the phase U becomes a waveform in which the period between G1 and G3 is narrowed to become an apex when the outer arc angle θa is narrowed, and the waveform of the line voltage becomes a waveform that approximates a triangular waveform as the peaks F approach the apex portion W approach. On the other hand, the voltage waveform of the phase U to a waveform in which a section in the period between G1 and G3 is flattened when the outer arc angle θa is expanded, and the waveform of the line voltage becomes a waveform approximating a trapezoidal waveform while the peaks F the apex portion W leave, which leads to the tendency to be superimposed by the 5th and 7th spatial harmonics.

With regard to the middle groove 21 requires the gap G between the rotor 12th and the stator teeth 15 as mentioned above, a high magnetic resistance (or a low permeability), but since the tendency to overlap is increased by the 5th and 7th harmonics, if it is expanded too much, the outer arc angle must θa have a minimum required shape dimension.

With reference to 41 should SO the other to the rotor 12th directed open end should represent the measured width of each of the slots TB the face width of the inner circumference of each of the stator teeth 15 to represent TW the end portion ready of the stator tooth 15 represent that at the remaining portion inward from the inner circumference of the stator tooth 15 is measured, and should AG the gap width across the gap G between the rotor 12th and the stator teeth 15 be. Then the rotor 12th and the stator 15 designed to fulfill relationships as follows.

First the middle grooves 21 , each of which has a width that is the width of the forehead TB one of the stator teeth 15 is equal to or greater than this, meet the requirement of increased magnetic resistance across the gap G. It follows that the lower limit for the outer arc angle θa as
2 × tan ^-1 {(TB / 2) / (R1 + AG)} ≦ θa
is expressed as the shape that is given by the forehead width TB and the rotor axis is enclosed, resembles an isosceles triangle (2 × a right triangle).

In addition, with regard to the automatic insertion of the stator windings and the required energy density, it is necessary that the opening width SO every slot 18th is larger than the gap width AG of the air gap width G, ie SO> AG. According to this relationship, the magnetic resistance at the gap G is lower than that at the opening space of the slot 18th what a reduction in density with the rotor 12th interacting magnetic flux lines from an acute corner section K (see 38 ) of each of the stator teeth 15 makes necessary. Therefore, it is necessary that each of the middle grooves 21 located on an arc that is in arc degree an arc between the adjacent two inner peripheral sections 15a on every second stator tooth 15 is equal to or greater than this. It follows that the upper limit of the outer arc angle θa equally as
θa ≦ 2 × tan ^-1 [{SO + (TB / 2)} (R1 + AG)}].
is expressed.

Next defines the inner arc angle θb for the bottom of the middle groove 21 an arc between the adjacent two inner peripheral sections 15a on every second stator tooth 15 as its upper limit, which is why the upper limit is similar to the outer arc angle θa is expressed as θb ≦ 2 × tan ^-1 [{SO + (TB / 2)} / (R1 + AG)}].

Because the arc for the lower limit of the outer arc angle θa on the other hand, the width of the forehead TB of the stator tooth 15 is to regulate the reluctance at the gap G so that it increases, the middle groove 21 on the bottom of the groove 21a waive, which is why the lower limit of the inner arc angle θb can be expressed as 0 ° ≦ θb.

In addition, the forehead width TB and the tail section width TW of the stator tooth 15 TW ≦ TB because the above conditions would not be met if the end portion of each of the stator teeth 15 would be pointed.

The rotor reduces similarly 12th with medium grooves 21 during operation in drive mode under low load conditions as shown in 44 resulting from a comparison of those made by this rotor 12th generated torque waveform with that generated by the rotor 12C without middle grooves 21 using the rotor 12C as the base unit - 1.0 (per unit) - the amplitude of the torque waveform can be seen more strongly, thereby limiting the torque ripple than is the case with the rotor 12C the case is. As from the in 45 results shown after processing the in 44 waveforms shown by Fourier series expansion is the 6th harmonic torque component of the torque waveform generated by the rotor 12th with medium grooves 21 generated is significantly reduced.

In addition, the influence of the middle grooves is mainly in the foregoing 21 described on the torque properties, but are the middle grooves 21 useful as marks in manufacture such as assembly. For example, when twisting it around the permanent magnet 16 to rotate in different positional relationships along the axis direction, possible the presence of twisting from the through the central grooves 21 to confirm straightness generated.

Referring to an in 46 less preferred rotor shown 12D without side grooves 22 is over 47 it can be seen that the magnetic flux density at the gap G assumes a waveform during operation under no load which approximates a trapezoidal wave deviating from the fundamental wave. At this gap G, the superposition of the split magnetic flux waveform causes that according to the stator teeth 15 on the stator 11 , the permanent magnet 16 one in a “V” shape on the rotor 12D pairs and the river barriers 17b and 17c which is arranged in a "V" -shaped design is determined by spatial harmonics an increased torque ripple and an increased iron loss.

The stator teeth correspond in the split magnetic waveform 15a to 15g for a magnetic pole of the rotor 12D parts A to C of the waveform, each part having an electrical angle of 30 degrees, since a longitudinal axis is shown at 90 degrees in electrical angle, a transverse axis is shown at 0 degrees in electrical angle, and the other transverse axis at 180 degrees in electrical angle is shown. This split magnetic flux waveform is near part A, the flux barriers 17c (Openings) on the longitudinal axis side, deepened. A comparison with the basic waveform shows that the magnetic flux density is too high on the one hand during a range from C to B and on the other hand during a range from E to F. It follows that the harmonics overlap on the second and third stator teeth 15b and 15c from the longitudinal axis in a forward direction of rotation of the rotor 12D and on the second and third stator teeth 15e and 15f from the longitudinal axis in a reverse reverse direction to the forward direction.

This is why it is with the rotor 12D advantageous in two places on the outer circumference 12a that deviate from the longitudinal axis within a range of ± 30 to 60 degrees, a pair of side grooves 22 form, one between the stator teeth 15b and 15c to the stator 15 is directed, and the other between the stator teeth 15e and 15f is directed to the stator to reduce the concatenating magnetic flux density.

Incidentally, one way to counteract (decrease) a torque ripple component with a particular order of an IPM motor includes twisting axially disposed portions of a rotor, a portion with respect to the adjacent portion, or, in other words, performing twist stages . In the case of a three-phase motor, for example, a 12th order torque ripple component can be counteracted (reduced) by exposing one rotor to an electrical angle of 15 degrees per step.

In particular, the 12th harmonic chained to the magnetic flux is expressed as a function. You can as
F (θ) = sin12θ
be scheduled.

Then the waveform shifted by 15 degrees in electrical angle is called
F (θ + 15 °) = sin12 (θ + 15 °) = -sin12θ
expressed.

Theoretically, the 12th harmonic is counteracted and is thereby canceled out by the 11th and 13th spatial harmonics. This leads to a reduction in the 12th torque ripple.

When the split magnetic flux waveform with which harmonics are chained is examined not only during an operation under no load but also under a load condition, as in 48 shown waveforms. 48 shows two waveforms, one in the case without side grooves 22 and is produced without twist levels, and the other in the case without side grooves 22 and is generated with provision of torsion levels.

From these split magnetic flux waveforms, it can be seen that the provision of twist levels restricts the overlying harmonics, but it can be seen from a comparison with the fundamental waveform that the twist magnetic flux density occurs both during operation under load conditions and during no load during a range from B to C and during one Range from E to F is too high.

Thus, with the electric lathe 10th suitable mold dimensions for each of several pairs of side grooves 22 determined on the basis of the torque properties for the torque and the torque ripple.

So much for the side grooves 22 each pair are affected, determine as in 49 shown (see also 26 ) induced angles θ2 , θ3 , θ4 , θ5 where each of the side grooves 22 is to be formed
where it is θ2 around the induced angle between the longitudinal axis and a reference plane, which extends from a wall surface of one of the permanent magnets 16 each pair near the outer circumference 12a (= a wall surface 17au of a magnetic opening 17th for the permanent magnet 16 near the outer circumference 12a , please refer 26 ) extends, the so-called "magnet opening angle, through which a magnet is separated from the longitudinal axis";
at θ3 around the included angle between the longitudinal axis and a radial reference line that extends from the rotor axis to a reference point at a corner 16b of the permanent magnet 16 that the outer circumference 12a of the rotor 12th closest, extends, is the so-called "magnetic edge arc angle by which the magnetic edge is rotated from the longitudinal axis about the rotor axis";
at θ4 around the outer included angle between the longitudinal axis and a radial reference line that extends from the rotor axis to a reference point on the edge furthest away from the longitudinal axis 22o a lateral groove extends acts;
at θ5 around the internal included angle between the longitudinal axis and a radial reference line that extends from the rotor axis to a reference point at the edge 22i the side groove 22 which is the least distant from the longitudinal axis.

If each of the side grooves 22 of a pair over the magnetic edge arc angle θ3 or the magnet opening angle θ2 is located far from the longitudinal axis, the side grooves have a range from C to D and a range from F to G in the split magnetic flux waveform shown in FIG 47 shown, and therefore fall outside of places where a reduction in magnetic flux is necessary. As for the rotor 12th concerns, requires a web 12c that is between the outer circumference 12a and the river barrier 17b and connects the inside and outside of a pole due to the fact that it is exposed to a concentration of Von Mises stress caused by centrifugal force during a high-speed rotation of the permanent magnets 16 comes from a certain thickness so that its breaking is avoided. Therefore, the place of formation of each of the side grooves must be 22 through inequality
θ5 (inner inclusion angle) < θ4 (outer angle of inclusion) ≦ θ3 (Magnetic edge arc angle)
be determined.

The shape dimensions of each of the side grooves 22 of a pair are based on the in 50 and 51 torque characteristics shown of the average torque, the harmonic torque components and the torque ripple, which are obtained when a ratio θ5 (inner included angle) / θ4 (outer included angle) is used as a parameter.

First, the torque ripple can be effectively reduced while maintaining a certain level of average torque when viewed in FIG 50 Torque characteristics shown during operation under a maximum load, the rotor 12D (θ5 / θ4 = 1.0), the one without any lateral grooves 22 is used as the base unit (1.0 [per unit]), each side groove 22 Has mold dimensions that have a relationship of
0.945 ≦ θ5 / θ4 ≦ 0.98
fulfill. In particular, the torque ripple can be kept to a minimum if the lateral grooves 22 satisfy the relationship of θ5 / θ4 ≦ 0.97.

In addition, the torque can be effectively reduced while maintaining a certain level of average torque if each side groove 22 considering the in 51 Torque characteristics shown during operation under high loads has mold dimensions that have a relationship of
θ5 / θ4 ≦ 0.98
fulfill.

The shape dimensions of each of the side grooves 22 of a pair are based on the in 52 shown torque properties of the average torque and the torque ripple, which are obtained when a ratio RG (groove depth) / AG (air gap width) (see 49 ) is used as a parameter.

First, the torque ripple can be effectively reduced while maintaining a certain level of average torque when viewed in FIG 52 Torque characteristics shown during operation under a maximum load, the rotor 12D (RG / AG = 0.0) without any lateral grooves 22 is used as the base unit (1.0 [per unit]), each side groove 22 Has mold dimensions that have a relationship of
0.0 ≦ RG / AG ≦ 0.73
fulfill. In particular, the torque ripple can be kept to a minimum if the lateral grooves 22 fulfill the relationship of 0.30 ≦ RG / AG ≦ 0.45.

This enables the electric lathe 10th , the magnetic flux density in a by the representation of the split magnetic flux waveform in 53 specified trapezoidal wave in a range from B to C and in a range from E to F decrease when the side grooves 22 at suitable places in the outer circumference 12a of the rotor 12th are formed.

In addition, the electric lathe 10th reduce the torque ripple not only during operation under a maximum load, but also during operation under a low load if the side grooves 22 at the appropriate places in the outer circumference 12a of the rotor 12th are formed as easily from the in 54 torque waveform shown during operation under a maximum load and in 55 Torque waveform shown is visible during operation under a low load.

Furthermore, the electric lathe 10th Reduce the cogging torque by more than 50% if the side grooves 22 at suitable places in the outer circumference 12a of the rotor 12th are formed as in a 56 shown representation of the cogging torque waveform is shown.

Referring now to the rotary electric machine 10th can with the IPM structure, in which the permanent magnets 16 each pair so in the rotor 12th are embedded that one in 57 shown positional relationship is met, a change in magnetic flux with a tooth of the stator teeth 15 of the stator 11 is chained as in 58 shown can be approximated by a square wave. When low-order harmonics such as the 5th and 7th harmonics overlap this magnetic flux, they cause iron loss and torque ripple, that is, they cause the difference between the largest and the lowest torque to increase during one revolution, which is not only becomes a reason for a decrease in efficiency due to dispersion as thermal energy, but also a factor for the occurrence of vibrations and noise. The iron loss can be separated into a hysteresis loss and an eddy current loss. Since the hysteresis loss can be expressed as the product of frequency and flux density, and the eddy current loss can be expressed as the product of the square of the frequency and the square of the flux density, restricting the spatial harmonics can reduce the power loss and the efficiency of energy conversion with respect improve the electrical energy introduced. Referring now to 58 , where the vertical axis represents the magnetic flux caused by the rotor and called "magnetic rotor flux", and the horizontal axis represents time, the square wave approximating the magnetic flux wave is illustrated in electrical degrees for a cycle T (4L1 + 2L2) , being during each of the durations L1 no interlinking magnetic flux between the rotor 12th and a stator tooth 15 persists, but for a duration L1 a positive interlinking magnetic flux is formed in the first half cycle and for a different duration L2 a negative interlinking magnetic flux is formed in the second half cycle.

$$\text{f r}=\frac{\mathrm{\partial }\text{W}}{\partial \text{x}}=\frac{1}{2\mu }{\text{B}}^2\text{S}\frac{\partial }{\partial \text{x}}\left(\text{x}\right)=\frac{1}{2\mu }{\text{B}}^2\text{S}$$

wobei φ der Magnetfluss ist, W die magnetische Energie ist, fr die radiale elektromagnetische Kraft ist, R_g die Reluktanz ist, B die Magnetflussdichte ist, S der Bereich ist, durch den der verkettende Fluss verläuft, x der Abstand des Luftspalts G ist, und µ die Permeabilität des Flussfließwegs ist.The electromagnetic noise in a motor (ie, a rotating electrical machine) is generated by vibrations of its stator when electromagnetic forces act on the stator. As the electromagnetic forces acting on the stator, there is a radial electromagnetic force caused by the magnetic coupling between the rotor and the stator, and a circumferential electromagnetic force caused by the torque. In terms of radial electromagnetic force, the magnetic energy W and the radial electromagnetic force, when viewed so that the motor is approximated by a linear magnetic circuit per one of the stator teeth, is expressed by the following equations (9) and (10): $$\text{W}=\frac{1}{\mathrm{2nd}}{\varphi }^{\mathrm{2nd}}{\text{R}}_{\text{G}}=\frac{1}{\mathrm{2nd}}{\left(\text{B}\cdot \text{S}\right)}^{\mathrm{2nd}}\cdot \frac{x}{\mu \text{S}}=\frac{1}{\mathrm{2nd}\mu }{\text{B}}^{\mathrm{2nd}}\cdot \text{x}\cdot \text{S}$$

$$\text{for r}=\frac{\mathrm{\partial }\text{W}}{\partial \text{x}}=\frac{1}{\mathrm{2nd}\mu }{\text{B}}^{\mathrm{2nd}}\text{S}\frac{\partial }{\partial \text{x}}\left(\text{x}\right)=\frac{1}{\mathrm{2nd}\mu }{\text{B}}^{\mathrm{2nd}}\text{S}$$

where φ is the magnetic flux, W is magnetic energy for which radial electromagnetic force is R _g the reluctance is B the magnetic flux density is S the area through which the chain flow passes is x the distance of the air gap G and µ is the permeability of the river flow path.

If the room harmonics are taken into account and the magnetic flux density B is expressed by the following equation (11), the spatial harmonic superposition is a factor for an increase in the radial electromagnetic force fr since the square of the magnetic flux density B ^{2 is} included. In other words, a reduction in the harmonics causes not only a reduction in the torque ripple, but together with a reduction in the electromagnetic noise of the motor also causes an improved energy conversion efficiency. $$\text{B}={\displaystyle \sum _{\text{t}=1}^{\text{t}}{\text{B}}_{\text{t}}\text{sin t}\left(\theta +{\delta }_t\right)}$$

As with an electric lathe 10th which represents a three-phase IPM motor with such a distributed winding that a winding design is provided which corresponds to a value of slots per phase per pole of 2 (number of slots / phase / pole = 2), a number of twelve slots 18th will correspond to the magnetic poles of each pair, there are twelve places for one cycle in electrical degrees where the associated one slot 18th is exposed to a high reluctance, which causes the magnetic flux waveform to be overlaid by the nth 11th and 13th order harmonics. The nth 11th and 13th order harmonics, referred to as "slot harmonics", can be easily reduced by rotating magnet sections arranged in the axis direction about the rotor axis, a section with respect to an adjacent section by an angle of twist , which depends on the position placed in the axis direction.

But since the magnetic flux waveform of the interlinking magnetic rotor flux with a stator tooth 15 as in 58 is approximately a square wave, it is structurally easy for the nth (ie, the 6th order = the 6th harmonic) spatial harmonics of the 5th and 7th order to be superimposed, which are therefore difficult to reduce.

Therefore, with such a structure, there is a need to reduce the 5th and 7th harmonics in order to reduce the torque ripple.

• Bedingung 1: $$\text{cos5}\mathrm{\omega }\cdot \text{L1}=\text{0}$$
  
• Bedingung 2: $$\text{cos7}\mathrm{\omega }\cdot \text{L1}=\text{0}$$
  
  $$\text{f}\left(\text{t}\right)=\frac{4}{\pi }{\displaystyle \sum _{k=1}^{\infty }\frac{\text{sin}\left\{\left(2\text{k}-\text{1}\right)\mathrm{\omega }\text{t}\right\}}{2\text{k}-1}}$$
  
  $$\begin{array}{c}\text{F}\left(\text{t}\right)=\frac{1}{2}\left[\text{f}\left(\text{t}-\text{L}1\right)+\text{f}\left(\text{t}+\text{L}1\right)\right]\\ =\frac{1}{2}\left[\frac{4}{\mathrm{\pi }}{\displaystyle \sum _{\text{k}=1}^{\infty }\frac{\text{sin}\left\{\left(2\text{k}-1\right)\mathrm{\omega }\left(\text{t}-\text{L}1\right)\right\}}{2\text{k}-\text{1}}}+\frac{4}{\mathrm{\pi }}{\displaystyle \sum _{\text{k}=1}^{\infty }\frac{\text{sin}\left\{\left(2\text{k}-\text{1}\right)\mathrm{\omega }\left(\text{t}+\text{L}1\right)\right\}}{2\text{k}-1}}\right]\end{array}$$
  
  $$\begin{array}{r}\text{F}\left(\text{t}\right)=\frac{1}{2}[\frac{4}{\pi }\left\{\text{sin }\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{3}\text{sin3}\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{5}\text{<figure-callout id="5" label="sin" filenames="DE102013223671B4\_0036.png,DE102013223671B4\_0043.png" state="{{state}}">sin</figure-callout> 5}\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{7}\text{sin7}\mathrm{\omega }\left(\text{t}-\text{L}1\right)\right\}\\ +\frac{4}{\mathrm{\pi }}\left\{\text{sin }\mathrm{\omega }\left(\text{t}+\text{L1}\right)+\frac{1}{3}\text{<figure-callout id="3" label="sin" filenames="DE102013223671B4\_0043.png,DE102013223671B4\_0053.png" state="{{state}}">sin</figure-callout> 3}\mathrm{\omega }\left(\text{t}+\text{L}1\right)+\frac{1}{5}\text{sin5}\mathrm{\omega }(\text{t}+\text{L}1)+\frac{1}{7}\text{<figure-callout id="7" label="sin" filenames="DE102013223671B4\_0043.png,DE102013223671B4\_0050.png" state="{{state}}">sin</figure-callout> 7 }\mathrm{\omega }\left(\text{t}+\text{L}1\right)\right\}]\end{array}$$
  
  $$\begin{array}{c}\text{F}\left(\text{t}\right)=\frac{4}{\mathrm{\pi }}[\text{sin }\omega \text{ t}\cdot \text{cos }\mathrm{\omega }\text{L1}+\frac{1}{3}\text{<figure-callout id="3" label="sin" filenames="DE102013223671B4\_0043.png,DE102013223671B4\_0053.png" state="{{state}}">sin</figure-callout> 3}\mathrm{\omega }\text{t}\cdot \text{cos }\mathrm{\omega }\text{ L1}\\ +\frac{1}{5}\text{ <figure-callout id="5" label="sin" filenames="DE102013223671B4\_0036.png,DE102013223671B4\_0043.png" state="{{state}}">sin</figure-callout> 5 }\mathrm{\omega }\text{t}\cdot \text{<figure-callout id="5" label="cos" filenames="DE102013223671B4\_0036.png,DE102013223671B4\_0043.png" state="{{state}}">cos</figure-callout> 5 }\mathrm{<figure-callout\; id="1"\; label="\omega \; L"\; filenames="DE102013223671B4\_0035.png,DE102013223671B4\_0036.png"\; state="\{\{state\}\}">\omega </figure-callout>}\text{ L}\text{ 1}+\frac{1}{7}\text{<figure-callout id="7" label="sin" filenames="DE102013223671B4\_0043.png,DE102013223671B4\_0050.png" state="{{state}}">sin</figure-callout> 7 }\mathrm{\omega }\text{t}\cdot \text{<figure-callout id="7" label="cos" filenames="DE102013223671B4\_0043.png,DE102013223671B4\_0050.png" state="{{state}}">cos</figure-callout> 7 }\mathrm{\omega }\text{ L}\text{1}]\end{array}$$
  

If the magnetic flux waveform is from the three-phase IPM structure to a stator tooth 15 is approximated by a square wave, the Fourier transform equation f (t) can be expressed by the following equation (12) while this illustrated magnetic flux waveform F (t) in 58 can be expressed by the following equation (13). If this magnetic flux waveform F (t) is rewritten as an approximation equation so that it contains the spatial harmonics up to the 7th order, it can be expressed by the following equation (14), which is used for a development under Using the trigonometric formulas for the product sum and the sum product can be converted to the following equation (15). From this equation (15) it can be seen that the following conditions must be met in order to reduce the 5th and 7th harmonics:

• Condition 1: $$\text{cos5}\mathrm{\omega }\cdot \text{L1}=\text{0}$$
  
• Condition 2: $$\text{cos7}\mathrm{\omega }\cdot \text{L1}=\text{0}$$
  
  $$\text{f}\left(\text{t}\right)=\frac{\mathrm{4th}}{\pi }{\displaystyle \sum _{k=1}^{\infty }\frac{\text{sin}\left\{\left(\mathrm{2nd}\text{k}-\text{1}\right)\mathrm{\omega }\text{t}\right\}}{\mathrm{2nd}\text{k}-1}}$$
  
  $$\begin{array}{c}\text{F}\left(\text{t}\right)=\frac{1}{\mathrm{2nd}}\left[\text{f}\left(\text{t}-\text{L}1\right)+\text{f}\left(\text{t}+\text{L}1\right)\right]\\ =\frac{1}{\mathrm{2nd}}\left[\frac{\mathrm{4th}}{\mathrm{\pi }}{\displaystyle \sum _{\text{k}=1}^{\infty }\frac{\text{sin}\left\{\left(\mathrm{2nd}\text{k}-1\right)\mathrm{\omega }\left(\text{t}-\text{L}1\right)\right\}}{\mathrm{2nd}\text{k}-\text{1}}}+\frac{\mathrm{4th}}{\mathrm{\pi }}{\displaystyle \sum _{\text{k}=1}^{\infty }\frac{\text{sin}\left\{\left(\mathrm{2nd}\text{k}-\text{1}\right)\mathrm{\omega }\left(\text{t}+\text{L}1\right)\right\}}{\mathrm{2nd}\text{k}-1}}\right]\end{array}$$
  
  $$\begin{array}{r}\text{F}\left(\text{t}\right)=\frac{1}{\mathrm{2nd}}[\frac{\mathrm{4th}}{\pi }\left\{\text{sin}\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{\mathrm{3rd}}\text{sin3}\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{5}\text{sin 5}\mathrm{\omega }\left(\text{t}-\text{L}1\right)+\frac{1}{7}\text{sin7}\mathrm{\omega }\left(\text{t}-\text{L}1\right)\right\}\\ +\frac{\mathrm{4th}}{\mathrm{\pi }}\left\{\text{sin}\mathrm{\omega }\left(\text{t}+\text{L1}\right)+\frac{1}{\mathrm{3rd}}\text{sin 3}\mathrm{\omega }\left(\text{t}+\text{L}1\right)+\frac{1}{5}\text{sin5}\mathrm{\omega }(\text{t}+\text{L}1)+\frac{1}{7}\text{sin 7}\mathrm{\omega }\left(\text{t}+\text{L}1\right)\right\}]\end{array}$$
  
  $$\begin{array}{c}\text{F}\left(\text{t}\right)=\frac{\mathrm{4th}}{\mathrm{\pi }}[\text{sin}\omega \text{t}\cdot \text{cos}\mathrm{\omega }\text{L1}+\frac{1}{\mathrm{3rd}}\text{sin 3}\mathrm{\omega }\text{t}\cdot \text{cos}\mathrm{\omega }\text{L1}\\ +\frac{1}{5}\text{sin 5}\mathrm{\omega }\text{t}\cdot \text{cos 5}\mathrm{\omega }\text{L 1}+\frac{1}{7}\text{sin 7}\mathrm{\omega }\text{t}\cdot \text{cos 7}\mathrm{\omega }\text{L}\text{1}]\end{array}$$
  

By the way, with reference to the in 58 shown magnetic flux waveform, the following equation (16) holds, inserting this equation into a transformation obtained from condition 1, that is, 5ω · L1 = ± π / 2, gives the following equation (17). If this equation is arranged using the fact that L1 and L2> 0, it can be seen that the 5th harmonic can be reduced to zero if the following condition 1A is met.

Angular frequency (angular velocity)

$$\mathrm{\omega \; =\; 2\pi \; /}\text{T}=\text{2nd}\mathrm{\pi \; /}\left(\mathrm{<figure-callout\; id="1"\; label="4th\; L"\; filenames="DE102013223671B4\_0035.png,DE102013223671B4\_0036.png"\; state="\{\{state\}\}">4th\; </figure-callout>}\text{L}1+\mathrm{2nd}\text{L}\mathrm{2nd}\right)$$

• Condition 1: $$5\mathrm{\omega }\text{L1}=5\cdot \mathrm{2nd}\mathrm{\pi }\text{L1}\left(\mathrm{4th}\text{L1}+\mathrm{2nd}\text{L}\mathrm{2nd}\right)=\pm \mathrm{\pi \; /\; 2}$$
  
• Condition 1A: $$\text{L1}=\text{L}\mathrm{2nd}/\mathrm{8th}$$
  

• Bedingung 2: $$\mathrm{7\omega }\text{L1}=7\cdot 2\mathrm{\pi }\text{L1}\left(4\text{L1}+2\text{L}2\right)=\pm \mathrm{\pi /2}$$
  
• Bedingung 2A: $$\text{L1}=\text{<figure-callout id="2" label="L" filenames="DE102013223671B4\_0038.png,DE102013223671B4\_0043.png" state="{{state}}">L</figure-callout>}2/12$$
  

Similarly, since the transformation obtained from Condition 2 is expressed by the following equation (18), when this equation is arranged using the fact that L1 and L2> 0, it can be seen that the 7th harmonic is reduced to zero can be satisfied if the following condition 2A is met.

• Condition 2: $$\mathrm{7\omega }\text{L1}=7\cdot \mathrm{2nd}\mathrm{\pi }\text{L1}\left(\mathrm{4th}\text{L1}+\mathrm{2nd}\text{L}\mathrm{2nd}\right)=\pm \mathrm{\pi \; /\; 2}$$
  
• Condition 2A: $$\text{L1}=\text{L}\mathrm{2nd}/\mathrm{12th}$$
  

$$2\text{L}1+\text{L}2=\mathrm{\pi }/4\mathrm{\omega }$$

The following also applies to an electric lathe 10th with a winding design corresponding to slots per phase per pole of 2 (SSP = 2), the relationship that 45 in mechanical degrees = one half cycle T / 2 in electrical degrees. Using the outside radius R1 of the rotor 12th and its peripheral speed V an arrangement is made to give the following equations (19) and (20). $$\begin{array}{c}\text{V}\left(\text{m / sec}\right)=\mathrm{2nd}\mathrm{\pi }\text{R1}\cdot \left(45°-360°\right)\left(\text{T / 2}\right)\\ =\mathrm{2nd}\mathrm{\pi }\text{R1}\cdot \left(45°/360°\right)/\left\{\left(\mathrm{<figure-callout\; id="1"\; label="4th\; L"\; filenames="DE102013223671B4\_0035.png,DE102013223671B4\_0036.png"\; state="\{\{state\}\}">4th\; </figure-callout>}\text{L}1+\text{2L2}\right)/\mathrm{2nd}\right\}\\ =\text{R1}\left(\text{m}\right)\cdot \mathrm{\omega }\left(\text{rad / sec}\right)\end{array}$$

$$\mathrm{<figure-callout\; id="1"\; label="2nd\; L"\; filenames="DE102013223671B4\_0035.png,DE102013223671B4\_0036.png"\; state="\{\{state\}\}">2nd\; </figure-callout>}\text{L}1+\text{L}\mathrm{2nd}=\mathrm{\pi }/\mathrm{4th}\mathrm{\omega }$$

• 5. Raumharmonische = 0 ⇒ (L2, L1) = (π/5ω,π/40ω)
• 7. Raumharmonische = 0 ⇒ (L2,L1)= (3π/14ω,π/56ω)

By inserting conditions 1A and 2A into the above equation, the following conditions are obtained:

• 5th space harmonic = 0 ⇒ (L2, L1) = (π / 5ω, π / 40ω)
• 7.Space harmonic = 0 ⇒ (L2, L1) = (3π / 14ω, π / 56ω)

With regard to the electric lathe 10th restricts the use of a design that meets the following reference expression ( 21 ) meets the torque ripple by offering the tendency to decrease the 5th and 7th order harmonics. $$\mathrm{\pi \; /\; 5\omega }\leqq \text{L2}\leqq \mathrm{3rd}\mathrm{\pi \; /}\text{14}\mathrm{\omega }$$

The expression "L2" corresponds to an area in the 58 magnetic flux waveform shown in the in the rotor 12th a river flow path is formed that connects the stator teeth 15 lies opposite, and can be used to determine an opening angle θ6 for an area around the rotor axis from one to the other outer end of the flow barriers 17b on both sides of the permanent magnets 16 of a pair called the magnetic pole opening angle θ6 is referred to.

With reference to the in 58 Magnetic flux waveform shown, this angle may be due to the fact that it is using a reference expression of θ = ωt θ6 = ωL2 can be rewritten in various ways as follows. As with the electric lathe 10th in the form of a motor with 8 poles and 48 slots (where 6 slots correspond to a magnetic pole) with a wiring configuration corresponding to a value of the slots per phase per pole of 2 (SSP = 2), 2 poles among the 8 poles complete a cycle , corresponds to a rotation of the rotor 12th over 360 degrees in mechanical angle 4 cycles in electrical degrees and apply the following reference terms.
π / 5 (rad) ≦ θ6 (in mechanical angle) ≦ 3π / 14 (rad)
36 (degrees) ≦ θ6 (in mechanical angle) ≦ 270/7 (degrees)
θ6 (in mechanical angle) = (8 poles / 2 poles) θ6 (in mechanical angle)
144 (degrees) ≦ θ6 (in electrical angle) ≦ 154.3 (degrees)

From the above it can be seen that the permanent magnets 16 and the associated river barriers 17b on the electric lathe 10th as in 59 shown in such a way in the rotor 12th are arranged so that their arrangement follows the following magnetic pole opening angle θ6 for a pole. In 59 is an angle θ7 an inclusion angle between two transverse axes for a magnetic pole.
36 ° ≦ θ6 (in mechanical angle) ≦ 38.6 °
144 ° ≦ θ6 (in electrical angle) ≦ 154.3 °

Incidentally, the magnetic pole opening angle corresponds θ6 for a pole in the rotor 12th in the approximating waveform to that in 58 shown magnetic flux waveform of duration L2 , during which the magnetic flux with a stator tooth 15 is chained. As in 59 shown, the magnetic flux waveform contains the chaining duration L2 that is centered between the two adjacent transverse axes and has a timing in accordance with a longitudinal axis. The angle also corresponds θ6 in 57 the induced angle between the adjacent two transverse axes and is a mechanical angle of 45 degrees, which corresponds to an electrical angle θ for a half cycle in the magnetic flux waveform.

Therefore, the electric lathe 10th a high quality rotation of the drive shaft in a drive mode 13 with reduced torque ripple, reduced vibration and reduced noise when the magnetic pole opening angle θ6 is limited to an angular range, ie, 144 ° θ θ6 (in the electrical angle) ^ 154.3 °, the spatial harmonic n of the phase voltage, which assume the order that the particular order 6f (6f = n ± m), ie n = 5, 7, is satisfied if the time harmonic m of the phase current assumes a basic waveform with the order m = 1. In addition, it can simultaneously perform a high-performance rotation with reduced loss because not only heat loss but also iron loss including hysteresis loss and eddy current loss are reduced due to the reduced torque ripple.

As in 60 shown, stray flux occurs at each of a pair of a rising edge and a falling edge of a rectangular waveform approximating the magnetic flux, causing a slight deviation from the theoretical values (the waveform). These small deviations can be regulated by a magnetic field analysis within the range of 144 ° ≦ θ6 (in the electrical angle) ≦ 154.3 °.

Due to the fact that it is during the operation of the electric lathe 10th in a drive mode under maximum load near a transverse axis, that is, a transverse axis flux flow path, where the magnetic rotor flux ψ _m has less influence than on the side of the longitudinal axis, for an influx of the magnetic stator flux ψ _r comes and the magnetic density tends to become high, the magnetic permeability becomes low and the torque drops when the cross-axis flux flow path is almost magnetically saturated. Therefore, for the magnetic pole opening angle θ6 taken a value that is close to 144 degrees (in the electrical angle) because the smaller (narrower) angle is favorable for an increase in the torque (the flow passage efficiency) by ensuring the cross-axis flow flow path, if possible. As a result of a magnetic field analysis of the correlation between the face width TB of the stator tooth 15 of the stator 11 , the opening width SO of the slot 18th and the air gap width AG between the rotor 12th and the stator tooth 15 was for the magnetic pole opening angle θ6 a value of 146.8 degrees (in electrical angle) is determined as the optimal value for reducing the 5th and 7th harmonics and the cogging torque.

In addition, the electric lathe 10th the magnet opening angle θ2 from the in 61 and 62 torque characteristics of the torque, the 6th and the 12th harmonic torque components and the torque ripple shown using the magnet opening angle θ2 determined as a parameter. In the 61 and 62 are the torque properties using θ2 = 90 degrees (in electrical angle) as the base unit - 1.0 (per unit) - illustrated.

As in 61 shown the magnet opening angle falls θ2 due to the fact that during operation in drive mode under a maximum load, the torque drops significantly when the magnet opening angle θ2 (in the mechanical angle) is less than 27.5 degrees, while the torque ripple and harmonic torque components become high when the magnet opening angle θ2 72.5 degrees, preferably in a range E of 27.5 degrees to 72.5 degrees, and more preferably falls in a range F of 37.5 degrees to 67.5 degrees in terms of torque.

In addition, the magnet opening angle drops θ2 as in 62 shown due to the fact that during operation in a drive mode under low loads, the torque drops rapidly when the magnet opening angle θ2 (in the mechanical angle) is less than 37.5 degrees, while the torque ripple and harmonic torque components become high when the magnet opening angle θ2 Exceeds 82.5 degrees, preferably in one area G from 37.5 degrees to 82.5 degrees, and it falls even better in a range H of 42.5 degrees to 67.5 degrees in terms of torque.

The magnet opening angle falls from the above-mentioned operation under a maximum load and that under low loads θ2 (in mechanical angle) preferably in a range from 37.5 degrees to 72.5 degrees, and falls even more in the range of 42.5 degrees to 67.5 degrees in terms of torque. In addition, 52.5 degrees are for the magnet opening angle θ2 Suitable to maximize torque while limiting torque ripple and harmonic torque components.

Because the electric lathe 10th with reference to 63 uses the IPM structure in which the permanent magnets 16 each pair in the rotor 12th are embedded and arranged in a "V" shape, in addition to the previously described central bridge 20 Side bridges 30th so on the outer end sides of the river barriers 17b provided that they can cooperate to form a connecting support which is in the form of a magnetic pole which is a pair of permanent magnets 16 against the von Mises tension, which comes from a centrifugal force during a rotation at high speed. The middle bridge 20 extends on a longitudinal axis in a radial direction from the rotor axis of the rotor 12th to connect and hold parts of the magnetic pole. Each of the side bridges 30th is between the outer circumference 12a of the rotor 12th and an outer end inner surface 17b1 one of the river barriers 17b is formed and connects two sections on the outer peripheral side (the outer peripheral side 12a) one of the permanent magnets 16 of a pair in the rotor 12th forms a magnetic pole with one of the sections on one side near a longitudinal axis for the pole and the other of the two sections on the side of a transverse axis between the pole and the adjacent magnetic pole.

Because every side bridge 30th with reference to the in 64 The vector field of the magnetic flux shown during operation under no load is arranged between the section on the longitudinal axis side and the section on the transverse axis side, it also acts as a creeping magnetic path for those through the permanent magnets 16 generated magnetic flux lines ψ _m (in 64 through the vectors V _m ), although it is ideal to prevent magnetic flux lines from circulating as much as possible. The side bridge 30th also acts while changing the area where the magnetic flux lines ψ _m by the permanent magnets 16 generated over the air gap G with one of the stator teeth 15 are chained in connection with the rotation of the rotor 12th between the side of the longitudinal axis and the side of the transverse axis as a magnetic path. This side bridge 30th can the magnetic reluctance depending on the shape of the outer end inner surface 17b1 the river barrier 17b that are behind the outer circumference 12a located, and can thereby regulate the magnetic flux density of the magnetic flux lines generated by the permanent magnets ψ _m resulting from the chaining according to the rotation of the rotor 12th run through, regulate.

With regard to the magnetic flux generated by the permanent magnets ψ _m the magnetic flux density at the air gap changes G between the stator 11 (the stator teeth 15 ) and the rotor 12th as in 65A shown in a waveform that approximates a rectangular waveform, the change in the magnetic flux density of this magnetic flux ψ _m causes the occurrence of a cogging torque. It can be ideal if the magnetic flux density of the magnetic flux generated by the magnets ψ _m is designed to change in a waveform that approximates a sinusoidal waveform, to provide smooth operation in a drive mode, but this is difficult to achieve. Therefore, reducing the time rate of change in magnetic flux (dψ / dt) is effective to reduce the cogging torque. In particular, it's like in 65B effectively shown to slow the time change in a rising zone and in a rear or converging zone of the magnetic flux (illustrated by the magnetic flux density waveform). Therefore, an optimization of the shape of the outer end inner surface 17b1 the river barrier 17b that the side bridge 30th forms, envisaged.

The side bridge also works 30th as in the magnetic flux vector field during operation under a maximum load of 66 also shown while changing the area in which the magnetic flux lines generated by the stator windings ψ _r (in 66 through the vectors V _r specified) over the air gap G with one of the stator teeth 15 are chained in connection with the rotation of the rotor 12th between the side of the longitudinal axis and the side of the transverse axis as a magnetic path. Because the magnetic flux density changes with regard to the magnetic flux generated by the stator windings ψ _r similar to the magnetic flux lines ψ _m changed in a waveform that approximates a rectangular waveform, it is easily superimposed by spatial harmonics of the (6f + 1) -th order such as the 5th, 7th, 11th or 13th order, causing torque ripple to occur becomes. Therefore, it is in terms of the side bridge 30th To reduce torque ripple effectively, the shape of the outer end inner surface 17b1 the river barrier 17b optimize in such a way that the time change of the magnetic flux ψ _r (dψ / dt) is slowly designed in a rising zone and in a rear or convergence zone of the magnetic flux.

Correspondingly, with regard to this electric lathe 10th the magnetic reluctance at the air gap G by regulating the thickness (viewed in the figures, the width) of each of the side bridges 30th by slowly changing the shape of the inner surface 17b1 the outer end of the associated one of the river barriers 17b in terms of the outer circumference 12a of the rotor 12th regulated.

Because the side bridges 30th with reference to 67 in section sections located on the outer sides (the side of the outer circumference 12a) the permanent magnet 16 every pair in the rotor 12th together with the middle bridges 20 provide connecting supports, the Von Mises stress converges during operation at high speeds at section sections MS1 in the outer circumference 12a of the rotor 12th , wherein each section on the longitudinal axis side of one of the flow barriers 17b for permanent magnets 16 of a pair, and also on sections of the area MS2 on the inner walls of the outer end of the river barriers 17b , each section of the region being on the side of the transverse axis of one of the flow barriers 17b for permanent magnets 16 of the couple. With regard to the side of the middle bridge 20 the Von Mises voltage converges at a portion MS3 in the rotor 12th on the outer circumference side of the central bridge 20 .

Therefore, the outer end inner surfaces 17b1 the river barriers 17b under return to 63 in terms of the side bridges 30th at intermediate points 17b1m between both corners 17b1c bent to the thickness (in 63 the width) of that portion of each of the side bridges 17b , which is located on the side of the transverse axis, to form a so-called “fillet design”.

This enables the regulation of each of the side bridges 30th in such a way that it causes the magnetic rotor flux ψ _m and the magnetic stator flux ψ _r at the air gap G gently change the area section located on the side of the transverse axis MS2 to a design that is beneficial for reducing Von Mises stress and by regulating the magnetic reluctance at the air gap G decrease gently.

In particular, the outer end inner surface comprises 17b1 each of the river barriers 17b for the side bridges 30th in the rotor 12th on both sides of the intermediate point 17b1m an inner surface portion 17b1d on the side of the longitudinal axis and an inner surface portion 17b1q on the side of the transverse axis. This outer end inner surface 17b1 is determined by the properties of the torque, the cogging torque and the torque ripple, which are obtained when the inclusion angle θ8 and θ9 can be changed as parameters, the inclusion angle θ8 between a radial reference line that extends from the rotor axis to the intermediate point 17b1m extends, and the longitudinal axis, and the inclusion angle θ9 between an extension level of the inner section 17b1d on the side of the longitudinal axis extending in a direction to the adjacent transverse axis and the transverse axis side inner surface portion 17b1q located. The properties are through the "per-unit system" using a construction in which the aforementioned magnetic pole opening angle θ6 is optimized and the inclusion angle θ8 The electrical angle is 74.2 degrees (the inclusion angle θ9 is 0, that is, there is no bend) as the base unit. In addition, the outer end inner surface 17b1 each of the river barriers 17b at both ends 17b1c and at the intermediate point 17b1m bent or, so to speak, "beveled" so that the inner surface section 17b1d on the side of the longitudinal axis and the inner surface portion 17b1q on the side of the transverse axis are gently and continuously connected to each other and to the remaining surface sections on both end sides.

First is out 68 it can be seen that during operation in a drive mode without load, the cogging torque is reduced if, with regard to the outer end-side inner surface 17b1 the river barrier 17b for the side bridge 30th , the inclusion angle θ8 (electrical angle) for the intermediate point 17b1m falls in an area I in which it is equal to or greater than 64.7 degrees but less than 74.2 degrees. It can also be seen that the cogging torque is reduced even more effectively if this included angle θ8 falls in a range J from 66 degrees to 72 degrees.

In addition, is off 69 It can be seen that during operation in a drive mode under a maximum load, the torque ripple is reduced, while the torque reduction is kept at a minimum value, with respect to the outer end inner surface 17b1 the river barrier 17b for the side bridge 30th , the inclusion angle θ8 (electrical angle) for the intermediate point 17b1m falls in a range K in which it is equal to or greater than 64.9 degrees but less than 74.2 degrees. It can also be seen that the torque ripple is reduced more effectively if this included angle θ8 preferably falls in a range L from 66 degrees to 68 degrees. It can be seen that the Torque ripple is effectively reduced while the torque reduction is kept even smaller when this included angle θ8 is even better in a range M from 70 degrees to 72 degrees close to 72 degrees.

Out 70 it can be seen that during operation in a drive mode under a maximum load, the torque ripple is more effectively reduced, while a reduction in torque is kept at a minimum value when considering the outer end inner surface 17b1 the river barrier 17b for the side bridge 30th , the inclusion angle θ9 (mechanical angle) between the extension plane of the inner surface section 17b1d on the side of the longitudinal axis and the inner surface portion 17b1q on the side of the transverse axis, that is, the angle referred to as the bending angle θ9 (mechanical angle) by which the inner surface portion 17b1q on the side of the transverse axis with respect to the inner surface portion 17b1d is bent on the side of the longitudinal axis, falls into an area N in which it is greater than 0 degrees but less than or equal to 37 degrees. It can be seen that the torque ripple is effectively reduced while the torque reduction is kept small when this included angle θ9 in one area P from 10 degrees to 27 degrees is close to 10 degrees.

Thus, according to the present invention, after removing that portion of each of the permanent magnets 16 each pair that forms a magnetic pole that is in an area B located on the side near a longitudinal axis between the permanent magnets 16 and replacing the removed section with a substantial flow barrier 17c the magnetic flux ψ _m through the permanent magnets 16 which is emitted in such directions that it is against the magnetic flux ψ _r the stator windings acts, eliminated, preventing them from counteracting (extinguishing) each other, and also the course of the magnetic flux ψ _r through the area B limited.

This represents significant amounts of magnetic moment T _m and reluctance moment T _r ready while providing a substantial reduction in the amount of use of the permanent magnets because of the magnetic fluxes ψ _r and ψ _m of each of the permanent magnets of the pair can be used on the longitudinal axis side, while the amount of use of the permanent magnets is reduced. In addition, thanks to a reduction in the induced voltage constants, this increases the output power at high speeds, and a decrease in the degree of heat resistance resulting from a limitation of the demagnetization caused by temperature changes due to a limitation of the heat generation from eddy currents by the permanent magnets 16 results, also contributed to a reduction in costs.

In addition, a high torque T can be generated effectively when the separation distance R2 to the axis center end of the river barrier 17c is set so that the relationships (size and shape) to the outer radius R1 and the inner radius R2 of the rotor 0.56 ^ R2 / R1 ≦ 0.84 and 0.54 ≦ R3 / R2 ≦ 0.82.

In addition, the river barriers offer 17c an efficient generation of a large torque when the separation distance DLd from each of the river barriers 17c to the outer periphery of the rotor 12th in relation to the outer radius R1 of the rotor has a relationship of 0.98 ≦ DLd / R1 <0.194 fulfilled. The river barriers 17c offer powerful generation of greater torque if preferably the two relationships are 0.12 ≦ DLd / R1 ≦ 0.14 and 1.2 ≦ (flow barrier opening angle θ1 ) / (Magnetic opening angle θ2 ) ≦ 1.7 are met or even better the relationships DLd / R1 = 0.139 and θ1 / θ2 = 1.52 are satisfied.

• 2×tan^-1{(TB/2)/(R1+AG)}≦θ_a≦2×tan^-1[{SO+(TB/2)}/(R1+AG)}], 0°≦θ_b≦2×tan^-1[{SO+(TB/2)}/(R1+AG)}], und TW ≦ TB.

In addition, by providing the in the rotor 12th formed middle grooves 21 the torque ripple can be effectively reduced by suppressing harmonic torque components when the ratio of the radial distance R4 to the groove bottom 21a in relation to the outer radius R1 of the rotor 12th is designed to fall in the range of 0.98 ≦ R4 / R1 <1.0. In addition, each of the middle grooves 21 Reduce torque ripple further by suppressing more harmonic torque components if their shape dimensions are designed to:

• 2 × tan ^-1 {(TB / 2) / (R1 + AG)} ≦ θ _a ≦ 2 × tan ^-1 [{SO + (TB / 2)} / (R1 + AG)}], 0 ° ≦ θ _b ≦ 2 × tan ^-1 [{SO + (TB / 2)} / (R1 + AG)}], and TW ≦ TB.

In addition, spatial harmonics that overlay the split magnetic flux waveform can be constrained if each side groove 22 on the rotor 12th Has mold dimensions satisfying a relationship of 0.945 ≦ θ5 / θ4 ≦ 0.98 and a relationship of 0.0 ≦ RG / AG ≦ 0.73, which makes it possible to decrease the operational efficiency by increasing the cogging torque that To prevent torque ripple and iron loss caused.

Furthermore, the torque can be made high under a maximum load condition and under a low load condition, and the torque ripple and the 6th and 12th harmonics (harmonic torque component) can be restricted, thereby restricting electromagnetic vibration and electromagnetic noise when considering the structure of the Permanent magnets 16 each pair, which are embedded in a “V” shape in the rotor, 144 ° ≦ magnetic pole opening angle θ6 (electrical angle) ≦ 154.3 ° and 27.5 ° ~ 37.5 ° ≦ magnetic opening angle θ2 (in mechanical angle) ≦ 72.5 ° ~ 82.5 ° or even better 37.5 ° ≦ magnetic opening angle θ2 (mechanical angle) ≦ 72.5 ° is met.

Furthermore, the cogging torque and the torque ripple can be reduced while the torque reduction is kept small if, in addition to the above construction, the included angle θ8 between the intermediate point 17b1m the side bridge 30th between the inner surface portion 17b1d on the longitudinal axis side and the transverse axis side inner surface portion 17b1q is set to a range from 64.9 degrees to 74.2 degrees (electrical angle) and the included angle θ9 between the extension plane of the inner surface section 17b1d on the longitudinal axis side and the transverse axis side inner surface portion 17b1q is set to a range from 0 degrees to 37 degrees (mechanical angle). Therefore, the electromagnetic vibrations of the stator cores resulting from the torque ripple are reduced, and the electromagnetic noise is also reduced in accordance with the electromagnetic vibrations. If the aim is to reduce the cogging torque, the conditions can be relaxed so that the inclusion angle θ8 is greater than 64.7 degrees.

In addition, the cogging torque and torque ripple are reduced more effectively, while the torque reduction is kept small when the included angle θ8 is set to a range of 66 degrees to 68 degrees or to a range of 70 degrees to 72 degrees and the inclusion angle θ9 is set in a range of 10 degrees to 27 degrees.

As a result, the rotor 12th in the stator 11 Manufactured at low cost to provide high quality operation with a high energy density.

In the present embodiment, an electric lathe 10th with the form of an 8-pole, 48-slot motor as an example, but it is noted that the present invention is not limited to this embodiment, but can preferably be applied to any structure that has a q slot value per pole per phase of 2 (q = 2). For example, the present invention can be applied to any engine assembly with 6 poles and 36 slots or 4 poles and 24 slots or 10 poles and 60 slots without modification.

The present invention is not limited to the exemplary embodiment described and illustrated, but encompasses all embodiments that produce effects equivalent to those to which the present invention is directed. Furthermore, the present invention is not limited to combinations of features of the objects defined by the individual claims, but is defined by any desired combinations of certain of all the features disclosed.

Claims (2)

An internal permanent magnet rotating machine (IPM) having a slot per phase per pole value of 2, comprising: a stator (11) configured to receive stator windings in slots between stator teeth; a rotor (12) rotatable about a rotor axis with respect to the stator (11) and having an outer periphery (12a); a plurality of pairs of permanent magnets (16) in the rotor (12), the permanent magnets (16) of each pair being arranged in a "V" shape that opens toward the outer periphery (12a) and forming a magnetic pole; and low permeability orifices (17c), each of which replaces the predetermined area portion of one of the permanent magnets (16) that would generate directed magnetic flux lines such that magnetic flux lines from the stator (11) are proximate to a longitudinal axis of a the magnetic poles would be extinguished if the permanent magnet (16) were in the predetermined range, wherein at the opening (17c) there is a holding projection for the permanent magnet (16), which comprises a section that runs around a corner of the permanent magnet (16) and clings to the permanent magnet (16) and an adjoining straight end section, the Retaining projection extends substantially perpendicularly from a boundary of the opening (17c) into the opening (17c), the rotor (12) in the outer circumference (12a) for the permanent magnets (16) of each pair having a central regulating groove (21) and a pair of side regulation grooves (22), the middle regulation groove (21) and the side regulation grooves (22) being parallel to the rotor axis, the middle regulation groove (21) being on the longitudinal axis, the side regulation grooves (22) being on the outer end sides of the permanent magnets (16), the rotor (12) having flux barriers extending from the outer end sides of the permanent magnets (16) to the outer circumference (12a) d es rotor (12), wherein the rotor (12) between the outer end inner surfaces (17b1) of the flow barriers and the outer periphery (12a) of the rotor (12) has side bridges (30), each of the side bridges (30) having one side in the vicinity of the longitudinal axis and the other side in the vicinity of the adjacent transverse axis between the adjacent two magnetic poles, the outer end inner surface (17b1) of each of the flux barriers at the rear of the outer circumference (12a) of the rotor (12) having an end corner and has another end corner, the outer end inner surface (17b1) of each of the flow barriers having an intermediate point between the one and the other end corner, an inner surface portion (17b1d) extending on the longitudinal axis side between the one end corner and the intermediate point, and a cross axis side inner surface portion (17b1q) extends between the intermediate point and the other end corner, with an included angle θ8 between a reference line extending from the rotor axis to the intermediate point and the longitudinal axis satisfies a relationship expressed as 64.7 degrees ≦ θ8 (electrical angle) ≦ 74.2 degrees, the inner surface portion (17b1d) on the longitudinal axis side being parallel to the outer circumferential surface (12a) of the rotor (12), wherein an inclusion angle θ9 between the transverse axis-side inner surface section (17b1q) and an extension of the inner surface section on the longitudinal axis side toward the longitudinal axis is as 0 degrees <θ9 (mechanical angle) ≦ 37, 5 degree relationship fulfilled. Electric IPM lathe after Claim 1 where the inclusion angle θ8 satisfies a relationship expressed as 64.9 degrees ≦ θ8 (electrical angle) ≦ 74.2 degrees.

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