Rotating electric machine

Abstract

Rotating electric machine (1) comprising the following: a rotor (14) which has a number of pairs of magnetic poles arranged in the circumferential direction of the rotor; and a stator (20) comprising a stator core (30) and a stator winding (40), wherein the stator core has a number of slots (31) arranged in a circumferential direction of the stator core and radially opposite the rotor, wherein the stator winding consists of a number of phase windings (41), each of which is wound onto the stator core such that it is inserted into corresponding slots of the stator core; wherein the stator core has circumferentially successive single-phase slots for each of the phase windings of the stator winding n, in which only the phase winding is accommodated, for each magnetic pole of the rotor, wherein n is a natural number greater than or equal to 2; Each of the phase windings of the stator winding has k sections, which contain a first section and a k-th section, where k is a natural number greater than or equal to 2; the first to k-th sections are arranged sequentially from one end to the other end of the phase winding; and the first section is accommodated in a different single-phase slot for the phase winding than the k-th section, and whereby Each of the phase windings of the stator winding consists of a plurality of electrical conductor segments (50) which are inserted into the single-phase slots for the phase winding and are electrically connected in series with each other, on an axial side of the stator core, each corresponding pair of sections of the electrical conductor segments located in the slot, which are accommodated in the single-phase slots for the phase winding, are connected by a bending section (52), On the other axial side of the stator core, each corresponding pair of end parts of the electrical conductor segments is connected to each other in order to establish a connection between them. all of the bending sections which connect the sections of the electrical conductor segments of the phase windings located in the slot to each other, form a first coil head (47) of the stator winding on one axial side of the stator core, and all end parts of the electrical conductor segments of the phase windings and the connections between the end parts formed a second coil head (48) of the stator winding on the other axial side of the stator core.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] The present application is based on Japanese patent applications No. 2011-208278, filed on September 24, 2011, No. 2012-15596, filed on January 27, 2012, and No. 2012-148570, filed on July 2, 2012, and claims the priorities of these applications. The entire content of these applications is incorporated into the present application by reference. BACKGROUND 1. Technical field

[0002] The present invention relates to rotating electrical machines, which are used, for example, in motor vehicles as electric motors and electric generators. 2. Description of the relevant state of the art

[0003] Rotating electrical machines are known which have a rotor and a stator. The rotor has a plurality of pairs of magnetic poles arranged circumferentially. The stator contains a stator core and a stator winding. The stator core has a number of slots arranged circumferentially, and the stator is radially opposite the rotor. The stator winding consists of a number of phase windings, each wound onto the stator core in such a way that it is inserted into corresponding slots of the stator core.

[0004] In order to ensure a high output of the rotating electric machine, the stator core is designed so that it has a number of circumferentially successive single-phase slots for each of the phase windings of the stator winding, into which only the phase winding of each magnetic pole of the rotor is accommodated.

[0005] For example, Japanese patent application publication JP 2000 - 69 729 A (hereinafter referred to as patent document 1 for the sake of simplicity) discloses a three-phase stator winding which is wound as a wave winding on the stator core which has two single-phase slots per phase winding of the stator winding and per magnetic pole of the rotor.

[0006] In detail, as in Fig. Figure 26A shows the stator winding consisting of a U-phase winding, a V-phase winding, and a W-phase winding. Each of the U-, V-, and W-phase windings contains a first section (a), a second section (b), a third section (c), and a fourth section (d). The four sections (a) to (d) are arranged sequentially from a terminal of the phase winding at one end of the phase winding to a neutral point of the stator winding at the other end of the phase winding. Considering only the U-phase winding as an example, we find, as in Fig. As shown in Figure 26B, the first section (a) and the fourth section (d) of the U-phase winding are accommodated in the same single-phase slots U1 of the stator core, while the second section (b) and the third section (c) of the U-phase winding are accommodated in the same single-phase slots U2 of the stator core. This means that the first and fourth sections (a) and (d) are accommodated in different single-phase slots for the U-phase winding compared to the second and third sections (b) and (c). In this case, the single-phase slots U1 are spaced circumferentially from each other by one magnetic pole pitch (i.e., one pitch between the magnetic north and south poles of the rotor); the single-phase slots U2 are also spaced circumferentially from each other by one magnetic pole pitch; each of the single-phase slots U1 is located immediately adjacent to one of the single-phase slots U2.Additionally, it should be noted that the V-phase winding and the W-phase winding of the stator winding are wound on the stator core in the same way as the U-phase winding.

[0007] Japanese patent application JP 2004-64914A (hereinafter referred to as patent document 2 for simplicity) discloses a three-phase stator winding wound on a stator core in a manner that is intermediate between a loop winding and a wave winding. The stator core has three single-phase slots, one for each phase winding of the stator core and one for each magnetic pole of the rotor. Furthermore, the stator winding is accommodated in each slot of the stator core in six layers with respect to the radial direction of the stator core. Specifically, the stator winding is first wound around the stator core as a loop winding, filling the four radially inner layers in each slot of the stator core, and then wound around the stator core as a wave winding, filling the two radially outer layers in each slot of the stator core. Each phase winding of the stator winding also contains sections one through seven.For each phase winding of the stator winding, the first section and the sixth section (i.e., the last section) of the phase winding are accommodated in the same single-phase slots for the phase winding.

[0008] This means that in both patent document 1 and patent document 2, the first and last sections of each phase winding of the stator winding are accommodated in the same single-phase slots for the phase winding.

[0009] JP 2008-35580A discloses a motor that can suppress a potential difference generated between adjacent moving coils at one coil end and prevent the formation of a partial discharge. The first moving coil of the six moving coils, which is connected to an external pull-out terminal, is arranged in a slot that does not adjoin phase slot groups or the like of other phases of the three slots that form the phase slot groups or the like. The moving coil on the neutral side of the moving coil, which is arranged such that it is circumferentially adjacent to the first moving coil in the slot that adjoins the slot in which the first coil is arranged, is in a position that is circumferentially adjacent to the first moving coil in the slot in which the first moving coil is arranged.

[0010] WO 2011 / 055 438 A1 discloses a stator that can be built compactly and generates high power. A method for manufacturing the stator is also disclosed. The stator comprises a split stator core with teeth and slots, and a double coil formed from a flat conductor. The split stator core has a first block with six slots for phases U, V, and W, and a second adjacent block. The flat conductor in the first slot of phase U (U1B1) forms a first loop coil together with the flat conductor in the second slot of phase U. The flat conductor in the second slot of phase U forms a second loop coil together with the flat conductor (D) in the first slot of phase U (U1B2). The second loop coil is arranged on the inner circumference of the first loop coil.

[0011] DE 103 42 755 A1 discloses a rotating electric machine comprising a plurality of phase coils, each of which is composed of a plurality of sub-coils formed by connecting segments. Each sub-coil consists of an inner slot conductor section, which is to be accommodated in each of the slots of each of the phase slot groups formed in a stator core, and an outer slot conductor section that projects from the slot. Of the plurality of sub-coils formed by each phase coil, in which the sub-coils are to be connected to the input / output terminal, its inner slot conductor section is accommodated in a slot that is not one of the end sections of the phase slot group in a circumferential direction of the stator core. This reduces the electrical potential difference between the outer slot conductor section extending into the slot and the outer slot conductor section of an adjacent phase coil, thereby improving the insulation performance. INVENTORIES BY THE INVENTORS

[0012] The inventors of the present invention have investigated the reason why the configurations for receiving the first and last sections of each phase winding in the same single-phase slots for the phase winding have been used according to the prior art.

[0013] Specifically, to minimize the height of the coil heads of the stator winding above the corresponding end faces of the stator core, it is advantageous to arrange all connections and the neutral point of the stator winding radially outside the stator core. In this context, the coil heads refer to those parts of the stator winding that are located outside the slots of the stator core and project from the corresponding axial end faces of the stator core.

[0014] To arrange all connections and the neutral point of the stator winding radially outside the stator core, it is further necessary to provide an even number of jumper wires to radially cross each coil head of the stator winding. Specifically, if the stator core has two single-phase slots per phase winding of the stator winding and per magnetic pole of the rotor, it is necessary to provide either zero (i.e., no) jumper wires or six (i.e., two per phase winding) jumper wires to cross the coil heads of the stator winding.

[0015] In cases where the number of jumper wires crossing the coil head radially is zero, the phase windings of the stator winding overlap each other in six layers axially along the stator core, regardless of the positions of the phase winding sections in the slots of the stator core. Furthermore, in such cases, the number of types (or configurations) of jumper wires used in the stator winding is nine.

[0016] Going into more detail shows Fig. 27A a case in which for each phase winding of the stator winding the first section (a) and the fourth section (d) of the phase winding are accommodated in the same single-phase slots, while the second section (d) and the third section (c) of the phase winding are accommodated in the same single-phase slots. Fig. Figure 27B shows another case in which, for each phase winding of the stator winding, the first section (a) and the second section (b) of the phase winding are accommodated in the same single-phase slots, while the third section (c) and the fourth section (d) of the phase winding are again accommodated in the same single-phase slots. In each of these cases, which are shown in the Fig. 27A and Fig. As shown in Figure 27B, six different types of jumper wires are arranged around the radial inner circumference of the stator winding to bridge the corresponding pairs of the first to fourth sections (a) to (d) of each phase winding of the stator winding. Conversely, three different types of jumper wires are arranged around the radial outer circumference of the stator core to bridge corresponding pairs of the first to fourth sections (a) to (d) of each phase winding of the stator winding. However, there are no jumper wires that radially cross the coil head of the stator winding. Therefore, the total number of types of jumper wires used in the stator winding is nine.

[0017] Furthermore, the bridging wires of the stator winding overlap each other in six layers with respect to the axial direction of the stator core.

[0018] Additionally, it should be noted that although in the Fig. 27A and Fig. Figure 27B shows six bridging wires extending on the radial inside of the stator core, but these bridging wires actually extend over the coil head of the stator winding without protruding radially inwards from the stator core. It should also be noted that the number of bridging wires extending radially over the coil head cannot be zero in cases where, for each phase of the stator winding, the first section (a) and the third section (c) of the phase winding are accommodated in the same single-phase slots, while the second section (b) and the fourth section (d) of the phase winding are again accommodated in the same single-phase slots.

[0019] On the other hand, the Fig. 28A to 28C three cases in which the number of bridging wires radially crossing the coil head is six.

[0020] In detail, it shows Fig. 28C describes a case in which, for each phase winding of the stator winding, the first section (a) and the second section (b) of the phase winding are accommodated in the same single-phase slots, while the third section (c) and the fourth section (d) of the phase winding are accommodated in the same single-phase slots. In this case, there are six bridging wires that extend radially across the coil head of the stator winding. Furthermore, all of the bridging wires used in the stator winding overlap each other in six layers in the axial direction of the stator core. In addition, the total number of types of bridging wires used in the stator winding is eight.

[0021] Fig. Figure 28B illustrates another case in which, for each phase winding of the stator winding, the first section (a) and the third section (c) of the phase winding are accommodated in the same single-phase slots, while the second section (b) and the fourth section (d) of the phase winding are accommodated in the same single-phase slots. In this case, six jumper wires are arranged radially over the coil head of the stator winding. Furthermore, all jumper wires used in the stator winding overlap in four layers with respect to the axial direction of the stator core. Additionally, the total number of types of jumper wires used in the stator winding is reduced to five.

[0022] Fig. Figure 28A shows yet another case in which, for each phase winding of the stator winding, the first section (a) and the fourth section (d) of the phase winding are accommodated in the same single-phase slots, while the second section (b) and the third section (c) of the phase winding are again accommodated in the same single-phase slots. In this case, there are six jumper wires that radially cross the coil head of the stator winding. Furthermore, all jumper wires used in the stator winding overlap each other in four layers in the axial direction of the stator core. Additionally, the total number of types of jumper wires used in the stator winding is reduced to four.

[0023] Among all stator designs which are in the Fig. 27A and Fig. The construction shown in figures 27B and 28A to 28C is according to Fig. 28A is most preferable with regard to minimizing the axial length of the stator winding and facilitating the manufacture of the stator. Accordingly, for the reasons stated above, the design of receiving the first and last sections of each phase winding in the single-phase slots for the phase winding has been widely used in the prior art.

[0024] However, the inventors of the present invention have identified a problem with stator windings for rotating electrical machines.

[0025] If, in particular, an electric motor uses a square wave voltage whose maximum voltage is equal to V0, as in Fig. As shown in Figure 29, when applied between the terminals of the phase windings of the motor's stator winding, the actual maximum phase-to-phase voltage of the stator winding (i.e., the actual maximum voltage across any two phase windings of the stator winding) is greater than V0 due to the voltage spike, which is in Fig. 30 is shown.

[0026] Fig. Figure 31 shows the change in the amplification factor of the actual maximum voltage from phase to phase of the stator winding in relation to the maximum voltage V0 as a function of frequency.

[0027] One can tell from Fig. 31, that the amplification factor reaches its peak value when the stator winding has a resonant frequency with respect to harmonic components of the square wave voltage placed between the terminals of the phase winding and the stator winding.

[0028] If the maximum phase-to-phase voltage of the stator winding is further increased, it may become necessary to increase the phase-to-phase spacing of the stator winding (for example, by increasing the thickness of the insulating coatings of the phase windings of the stator winding) in order to improve the electrical insulation between the phase windings and to prevent short circuits from occurring between the phase windings. SUMMARY OF THE INVENTION

[0029] According to one exemplary embodiment, a rotating electric machine is created, comprising a rotor and a stator. The rotor has a number of pairs of magnetic poles arranged circumferentially. The stator contains a stator core and a stator winding. The stator core has a plurality of slots arranged circumferentially, with the stator core radially opposite the rotor. The stator winding consists of a number of phase windings, each wound onto the stator core such that it fits into corresponding slots in the stator core. Furthermore, according to this embodiment, the stator core has, for each of the phase windings of the stator winding n, successive single-phase slots circumferentially for each magnetic pole of the motor, in which only the phase winding is accommodated, where n is a natural number greater than or equal to 2.Each of the phase windings of the stator winding has k sections, including a first section and a k-th section, where k is a natural number greater than or equal to 2. The first through k-th sections are arranged sequentially from one end to the other of the phase winding. The first section is accommodated opposite the k-th section in different single-phase slots for the phase winding.

[0030] With the design described above, the negative mutual inductance between the first and k-th sections can be minimized, thereby minimizing the decrease in the overall inductance of the stator winding due to this negative mutual inductance. Consequently, it is possible to lower both the resonant frequency and the resonant peak of the stator winding. As a result, it is possible to reduce the maximum phase-to-phase voltage of the stator winding, thereby decreasing the required phase-to-phase gap between the stator windings to ensure electrical insulation.

[0031] According to another exemplary embodiment, a rotating electrical machine is created, comprising a rotor and a stator. The stator includes a stator core and a stator winding. The stator core has a number of slots arranged circumferentially, with the stator radially opposite the rotor. The stator winding is formed from a number of phase windings, each wound onto the stator core such that it fits into corresponding slots in the stator core. Furthermore, according to this embodiment, each phase winding of the stator winding contains k sections arranged sequentially from one end of the phase winding to the other, where k is a natural number greater than or equal to 2.Each of the k sections is wound onto the stator core in such a way that the circumferential direction of advancement of the section reverses for each completion of a circumferential advance of 360° / k.

[0032] With the previously described design, the k phase winding sections of each stator winding can be accommodated separately in different slots for the corresponding phase windings. Consequently, it is possible to weaken the magnetic coupling between the k phase winding sections, thereby minimizing the negative mutual inductances between them. This minimizes the reduction in the overall inductance of the stator winding due to negative mutual inductance, thus lowering both the resonant frequency and the resonant peak of the stator winding. As a result, it is possible to reduce the maximum phase-to-phase voltage of the stator winding, thereby decreasing the required phase-to-phase spacing of the stator windings to ensure electrical insulation between them.

[0033] According to yet another exemplary embodiment, a rotating electrical machine is created which includes a rotor and a stator. The stator contains a stator core and a stator winding. The stator core has a number of slots arranged circumferentially and is radially opposite the rotor. The stator winding consists of a number of phase windings, each wound onto the stator core such that it is inserted into corresponding slots of the stator core. Furthermore, according to this embodiment, each of the phase windings of the stator winding consists of j sub-windings connected in parallel to each other between opposite ends of the phase winding, where j is a natural number greater than or equal to 2.Each of the sub-windings contains k sections, arranged sequentially from one end of the sub-winding to the other, where k is a natural number greater than or equal to 2. Counting from one end of the phase winding, sections with the same sub-winding number are accommodated in the same slots for the phase winding, so that they are adjacent to each other in the corresponding slots.

[0034] With the previously described setup, the first sections of the sub-windings of each phase winding of the stator winding can be radially separated from the k-th sections of the sub-windings, thereby weakening the magnetic coupling between the first and k-th sections. Consequently, it is possible to minimize the reduction in the overall inductance of the stator winding due to the negative mutual inductances between the first and k-th sections, thus reducing both the resonant frequency and the resonant peak of the stator winding. As a result, it is possible to lower the maximum phase-to-phase voltage of the stator winding and thereby shorten the necessary phase-to-phase gap of the stator winding to ensure electrical insulation between the phase windings of the stator winding.

[0035] According to yet another exemplary embodiment, a rotating electric machine is created which includes a rotor and a stator. The rotor has a number of pairs of magnetic poles arranged circumferentially. The stator includes a stator core and a stator winding. The stator core has a number of slots arranged circumferentially. The stator core is radially opposite the rotor. The stator winding consists of a number of phase windings, each of which is wound onto the stator core in such a way that it is inserted into corresponding slots of the stator core. Furthermore, according to this embodiment, the stator core has, for each of the phase windings of the stator winding 2j, circumferentially successive single-phase slots per magnetic pole of the rotor, into which only the phase winding is received, where j is a natural number greater than or equal to 2.Each of the phase windings of the stator winding consists of j sub-windings, which are connected in parallel between opposite ends of the phase winding. Each sub-winding consists of a first half on one end of the phase winding and a second half on the other end. For each of the phase windings of the stator winding, all of the first and second halves of the sub-windings are accommodated separately in different single-phase slots for the phase winding.

[0036] In the configuration described above, the first and second halves of each of the sub-windings of the stator winding are accommodated in two separate single-phase slots. Consequently, the magnetic coupling between the first and second halves of the sub-winding can be weakened, minimizing the negative mutual inductance between them. This minimizes the decrease in the overall inductance of the stator winding due to negative mutual inductance, thereby reducing both the resonant frequency and the resonant peak of the stator winding. As a result, the maximum phase-to-phase voltage of the stator winding can be reduced, thus shortening the required phase-to-phase spacing between the stator windings to ensure electrical insulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The present invention will be further explained in detail in the following description and in the accompanying drawings of exemplary embodiments, which, however, are not to be understood as limiting the invention to the specific embodiments, but serve the purpose of explanation and understanding.

[0038] The accompanying drawings depict: Fig. 1 a partial cross-sectional view showing the overall structure of a rotating electrical machine according to a first embodiment; Fig. 2 a perspective view of a stator of the rotating electric machine; Fig. 3 a schematic perspective view to illustrate a process of inserting electrical conductor elements to form a stator winding of the stator in slots which are formed in a stator core of the stator; Fig. 4A, Fig. 4B and Fig. 4C each shows a perspective view, a top view and a circumferential unfolding, which together explain the way in which each phase winding of the stator winding is wound as a wave winding around the stator core; Fig. 5A a connection diagram of the phase windings of the stator winding; Fig. 5B a schematic view showing the positions of the first to fourth sections (a) to (d) of a U-phase winding of the stator winding in single-phase slots U1 and U2 of the stator core; Fig. 6 a graphical representation showing the relationship according to Paschen's law between the voltage at the start of the discharge, the pressure and the distance between electrical conductors; Fig. 7 a graphical representation showing a comparison of the resonance frequency and the resonance peak between the stator according to the first embodiment and a stator of conventional design; Fig. 8A a schematic representation to explain the measurement positions for the phase-to-phase voltage in the stator winding in an experiment 1; Fig. 8B a schematic representation showing the construction of the stator according to the first embodiment, which was tested in experiment 1; Fig. 9 a graphical representation showing the measurement results according to Experiment 1; Fig. 10A and Fig. 10B a perspective view or a top view which together explain a first modification of the stator structure according to the first embodiment; Fig. 11A, Fig. 11B and 11C a perspective view or a top view or a full-scale development which together show a second modification of the stator structure according to the first embodiment; Fig. 12 a connection diagram of phase windings of a stator winding of a stator according to a second embodiment; Fig. 13 a schematic representation to illustrate the positions of sections of underwindings of each phase winding of the stator winding in corresponding single-phase slots of a stator core of the stator according to the second embodiment; Fig. 14 a connection diagram of phase windings of a stator winding of a stator according to a third embodiment; Fig. 15 a circumferential unfolding which clarifies the manner in which each phase winding of the stator winding is wound around a stator core of the stator according to the third embodiment; Fig. 16 a circumferential unfolding showing the manner in which each phase winding of the stator winding is wound around the stator core according to a comparative example of the third embodiment; Fig. 17 a schematic representation showing the positions of sections of the underwindings of each phase winding of the stator winding in corresponding single-phase slots of a stator core of a stator according to a fourth embodiment; Fig. 18 a schematic representation showing the positions of sections of underwindings of each phase winding of a stator winding in corresponding single-phase slots of a stator core in a stator according to a fifth embodiment; Fig. 19 a connection diagram of phase windings of a stator winding of a stator according to a sixth embodiment; Fig. 20 a schematic figure showing the positions of sections of underwindings of each phase winding of the stator winding in corresponding single-phase slots of a stator core of the stator according to the sixth embodiment; Fig. 21 a schematic representation showing the difference in electrical angle between the underwindings of each phase winding of the stator winding in the stator according to the sixth embodiment; Fig. 22 a schematic representation illustrating the construction of a stator according to a comparative example of the sixth embodiment; Fig. 23 a representation showing the distribution of the magnetic motor force in the stator according to the sixth embodiment; Fig. 24 a representation showing the distribution of the magnetic motor force in the stator according to the comparative example of the sixth embodiment; Fig. 25 a graphical representation showing a comparison of the magnetic disturbance level between the stator according to the sixth embodiment and the stator according to the comparison example; Fig. 26A a connection diagram of phase windings of a stator winding of a stator according to the state of the art; Fig. 26B a schematic representation showing the positions of sections of underwindings of each phase winding of the stator winding in corresponding single-phase slots of a stator core of the stator according to the prior art; Fig. 27A and Fig. 27B and 28A to 28C are each schematic representations showing different stator configurations investigated by the inventors of the present invention; Fig. 29 a waveform diagram of a voltage applied between terminals of phase windings of a stator winding in a conventional rotating electrical machine; Fig. 30 a waveform diagram of the actual phase-to-phase voltage of the stator winding when the voltage which is in Fig. 29 shows that it is placed between the terminals of the phase windings; and Fig. 31 a graphical representation showing the change in the voltage gain ratio of the stator winding as a function of the frequency in a conventional rotating electrical machine. DESCRIPTION OF EXECUTION FORMS

[0039] For example, embodiments are described below with reference to the Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 11, Fig. 12, Fig. 13, Fig. 14, Fig. 15, Fig. 16, Fig. 17, Fig. 18, Fig. 19, Fig. 20, Fig. 21, Fig. 22, Fig. 23, Fig. 24 to Fig. 25 described. It should be noted that, for the sake of clarity and better understanding, identical components with identical functions in the various embodiments are provided with the same reference numerals in each of the drawing figures as far as possible, and that descriptions of the identical components are not repeated to avoid repetition. [First embodiment]

[0040] Fig. Figure 1 shows the overall structure of a rotating electric machine 1 according to a first embodiment. The rotating electric machine 1 is designed so that it can be used as an electric motor in a motor vehicle.

[0041] As in Fig. Figure 1 shows a rotating electric machine 1 comprising a housing 10, a rotor 14, and a stator 20. The housing 10 consists of a pair of essentially cup-shaped housing parts 10a and 10b, which are clamped together at their open ends. The housing 10 has a pair of bearings 11 and 12 mounted within it, and a rotating shaft 13 is rotatably supported by these bearings through the housing 10. The rotor 14 is housed in the housing 10 and is attached to the shaft 13. The stator 20 is mounted in the housing 10 such that it surrounds the radial outer circumference of the rotor 14.

[0042] The rotor 14 contains a number of permanent magnets embedded in it at predetermined positions. These permanent magnets form pairs of magnetic north and south poles on the radial outer circumference of the rotor 14, such that they face the radial inner circumference of the stator 20. The magnetic poles are spaced apart from each other at a predetermined interval around the circumference of the rotor 14. Furthermore, the polarities of the magnetic poles alternate between north and south poles around the circumference. Additionally, the number of magnetic poles can be adjusted as appropriate according to the design specifications of the rotating electric machine 1. For example, in the present embodiment, the number of magnetic poles is selected to be eight (i.e., four north poles and four south poles).

[0043] It was now on Fig. 2. Reference is made to the stator 20, which contains a substantially ring-shaped stator core 30 and a three-phase stator winding 40, which consists of a U-phase winding, a V-phase winding and a W-phase winding.

[0044] The stator core 30 is formed, for example, by stacking a multitude of core laminations (or steel sheets) in the axial direction of the stator core 30. The stator core 30 has a number of slots 31 formed in a radial inner surface of the stator core 30 and spaced apart from each other circumferentially at a constant pitch. Each of the slots 31 extends in the axial direction of the stator core 30 such that the stator core 30 is penetrated in the axial direction, with each slot having a substantially rectangular cross-section perpendicular to the axial direction. For each of the slots 31, the depth direction of the slot 31 coincides with the radial direction of the stator core 30.

[0045] In the present embodiment, two slots 31 (or n slots 31, where n equals 2) are provided for each magnetic pole of the rotor 14, which has eight magnetic poles, and for each phase of the three-phase stator winding 40. This means that the stator core 30 has two circumferentially consecutive single-phase slots for each of the U-phase winding, the V-phase winding, and the W-phase winding of the stator winding 40, in which only the phase winding is accommodated, for each magnetic pole of the rotor 14. Accordingly, the total number of slots 31 provided in the stator core 30 is 48 (i.e., two times three times eight).

[0046] Each of the U, V, and W phase windings of the stator winding 40 is formed by inserting a number of substantially U-shaped electrical conductor segments 50 into corresponding slots 31 of the stator core 30 from one axial side of the stator core 30 and by welding corresponding pairs of free ends of the electrical conductor segments 50 together on the other axial side of the stator core 30. Each of the electrical conductor segments 50 is obtained into a substantially U-shaped form by bending a rectangular electrical conductor, the outer surface of which is covered by an insulating coating (not shown). Each of the electrical conductor segments 50 has an exposed area (not shown) at its respective free end where the insulating coating is separated from the electrical conductor segment 50.Corresponding pairs of the exposed areas of the electrical conductor segments are joined together by welding to form a welded joint (or weld) 56 between them.

[0047] In detail, as in Fig. Figure 3 shows that each of the electrical conductor segments 50 is essentially U-shaped and comprises a pair of straight sections 51 extending parallel to each other and a bent section 52 connecting the ends of the straight sections 51 on the same side. The bent section 52 includes a vertex 53 formed in the middle of the bent section 52, such that it extends parallel to one of the corresponding axial end faces 30a of the stator core 30. The bent section 52 also includes a pair of oblique sections 54, each formed on opposite sides of the vertex 53, such that they extend obliquely at predetermined angles with respect to corresponding axial end faces 30a of the stator core 30. Additionally, the following are designated in Figure 3: Fig. 3 the reference number 24 an insulator arranged such that it insulates the stator winding 40 (or the electrical conductor segments 50) from the stator core 30.

[0048] Furthermore, in the present embodiment, the following elements are included: Fig. Figure 3 shows the electrical conductor segments 50, which form the stator winding 40, as a plurality of pairs of first and second electrical conductor segments 50A and 50B. For each pair of first and second electrical conductor segments 50A and 50B, the straight sections 51 of the first electrical conductor segments 50A are inserted into different slots 31 of the stator core 30 than the straight sections of the second electrical conductor segments 50B. More precisely, the slots 31 into which the straight sections 51 of the first electrical conductor segment 50A are inserted are each adjacent to those slots into which the straight sections 51 of the second electrical conductor segment 50B are inserted.

[0049] For the pair of first and second electrical conductor segments 50A and 50B, which is located at the top right in Fig. As shown in Figure 3, for example, the first electrical conductor segment 50A is inserted with its right straight section 51 into the sixth layer (i.e., the radially outermost layer) of a slot 31A and with its left straight section 51 into the fifth layer of another slot (not shown), which is arranged counterclockwise from slot 31A by one magnetic pole pitch, i.e., by one pitch between the magnetic north and south poles of the rotor 14). On the other hand, the second electrical conductor segment 50B is inserted with its right straight section 51 into the sixth layer of a slot 31B, which is located counterclockwise from and indirectly adjacent to slot 31A, and with its left straight section 51 into the fifth layer of another slot (not shown), which is located counterclockwise from slot 31B by one magnetic pole pitch.This means that the first and second electrical conductor segments 50A and 50B are offset relative to each other by one slot pitch.

[0050] Furthermore, an even number of straight sections 51 of the electrical conductor segments 50 are inserted into each of the slots 31 of the stator core 30. More precisely, in the present embodiment, six straight sections 51 of the electrical conductor segments 50 are inserted into each of the slots 31 of the stator core 30 such that they are stacked radially on top of each other in six layers in the slot 31.

[0051] For each of the electrical conductor segments 50, the free end portions of the straight sections 51 of the electrical conductor segments 50, which project beyond the corresponding slots 31 on an axial end face of the stator core 30, are bent in opposite directions in the circumferential direction of the stator core 30 such that they extend at a predetermined angle relative to the corresponding axial end face 30a of the stator core 30. Consequently, each of the free ends of the straight sections 51 is formed into an inclined section 55, which extends in the circumferential direction of the stator core 30 substantially over half a magnetic pole pitch (see Fig. 2).

[0052] Furthermore, on the other axial end face of the stator core 30, corresponding pairs of inclined parts 55 of the electrical conductor segments 50 are welded together at their respective outer ends to form a weld point 56 between them and thereby establish the electrical connection. More precisely, for each of the three phase windings 41 (i.e., the U, V, and W phase windings) of the stator winding 40, all electrical conductor segments 50 that together form the phase winding 41 are electrically connected in series. Consequently, as in the Fig. Figures 4A to 4C show each of the phase windings 41 being wound as a wave winding around the stator core 30 with, for example, six turns in the circumferential direction of the stator core 30.

[0053] Furthermore, each of the phase windings 41 of the stator winding 40 contains, in addition to the essentially U-shaped electrical conductor segments 50, as shown in Fig. Figure 3 shows other electrical conductor segments of different shapes (not shown). These other electrical conductor segments include: an electrical conductor segment having a terminal for the phase winding 41 integrally formed on it; an electrical conductor segment having a zero-point or neutral-point line (i.e., a line that serves to connect to the neutral point of the stator winding 40); and electrical conductor segments each having a connection area for connecting two successive turns (for example, the first and second turns) of the phase winding 41.

[0054] It was further on Fig. Reference is made to section 5A. In the present embodiment, the three phase windings 41 of the stator winding 40 are connected in a star configuration to form a neutral point 44 between them. In other words, the U, V, and W phase windings 41 of the stator winding 40 are connected to each other at the neutral point 44 and are thus electrically connected to each other.

[0055] Furthermore, each of the U, V and W phase windings 41 of the stator winding 40 contains 2n sections, where n is a natural number greater than or equal to 2.

[0056] More precisely, in the present embodiment, each of the phase windings 41 of the stator winding 40 comprises a first section (a), a second section (b), a third section (c), and a fourth section (d), which are arranged sequentially from the terminal 43 of the phase winding 41 at one end of the phase winding 41 to the neutral point 44 of the stator winding 40 at the other end of the phase winding 41. This means that in the present embodiment, n equals 2. Furthermore, each of the first to fourth sections (a) to (d) is wound as a wave winding on the stator core 30.

[0057] Furthermore, for each of the phase windings 41, the first section is accommodated in a different single-phase slot 31 for the phase winding 41 compared to the 2nth section. Furthermore, the 2mth section, counting from the side of the terminal 43, is accommodated in the same single-phase slot 31 for the phase winding 41 as the (2m-1)th section, where m is a natural number that satisfies the condition 1 ≤ m ≤ n.

[0058] In detail, in the present embodiment, as described in Fig. As shown in Figure 5B, for the U-phase winding 41, the first section (a) is accommodated in the single-phase slots U1, while the fourth section (d) (i.e., the 2nth section) is accommodated in the single-phase slots U2. Here, the single-phase slots U1 are spaced apart circumferentially by a magnetic pole pitch; the single-phase slots U2 are also spaced apart by a magnetic pole pitch; each of the single-phase slots U1 is located immediately adjacent to one of the single-phase slots U2. Furthermore, since n equals 2, m equals 1 or 2. For this reason, the second section (b) (i.e., the 2mth section, where m equals 1) is accommodated in the same single-phase slots U1 as the first section (a) (i.e., the (2m-1)th section, where m equals 1). On the other hand, the fourth section (d) (i.e., the 2m-th section, where m is equal to 2) is accommodated in the same single-phase slot U2 as the third section (c) (i.e.,, the (2m-1)th section, where m is equal to 2). Additionally, it should be noted that, although not shown graphically, the V-phase winding and the W-phase winding 41 of the stator winding 40 are wound on the stator core 30 in the same way as the U-phase winding 41.

[0059] Furthermore, in the present embodiment, on one axial side (i.e., the lower side in Fig. 2) of the stator core 30, all of the bending sections 52 of the electrical conductor segments 50, which project from the axial end face 30a of the stator core 30, together form a first coil head 47 of the stator winding 40. On the other side (i.e., the top side in Fig. 2) of the stator core 30, all of the inclined parts 55 of the electrical conductor segments 50, which project from the other axial end face 30a of the stator core 30, as well as the connections 56, which are formed between the inclined parts 55, together form a second coil head 48 of the stator winding 40.

[0060] Furthermore, although not shown in the drawing, the bending sections 52 of the electrical conductor segments 50 are arranged radially in a given number of layers on one axial side of the stator core 30. On the other axial side of the stator core, as shown in Fig. Figure 2 shows the connections 56 formed between the oblique parts 55 of the electrical conductor segments 50, arranged circumferentially at predetermined intervals and radially in a given number of layers.

[0061] Furthermore, in the present embodiment, the maximum voltage applied between the terminals 43 of the U, V, and W phase windings 41 of the stator winding 40 is set, based on Paschen's law, to be greater than or equal to 330 V. Additionally, as shown in Fig. Figure 6 shows that, according to Paschen's law, an electric charge can occur between electrical conductors at atmospheric pressure if the voltage between the electrical conductors is not below 330 V.

[0062] The rotating electric machine 1 described above, according to the present embodiment, has the following advantages.

[0063] In the present embodiment, the rotating electric machine 1 comprises the rotor 14 and the stator 20. The rotor 14 has four pairs of magnetic north poles and magnetic south poles, which are arranged at a predetermined spacing in the circumferential direction of the rotor 14 (see Fig. 5B). The stator 20 contains the stator core 30 and the stator winding 40. The stator core 20 has 48 slots 31 arranged circumferentially, with the stator core radially opposite the rotor 14. The stator winding 40 consists of U-, V-, and W-phase windings 41, each of which is wound onto the stator core 30 as a wave winding such that it is inserted into corresponding slots 31 of the stator core 30. More precisely, the stator core 30 has n consecutive single-phase slots 31 circumferentially for each of the phase windings 41 of the stator winding 40, into which only the phase winding 41 is received, at each magnetic pole of the rotor 14, where n is a natural number not less than 2 (for example, n = 2 in the present embodiment). Each of the phase windings 41 of the stator winding 40 contains 2n sections (i.e., four sections in the present embodiment), which are arranged sequentially from the terminal 43 of the phase winding 41 to the neutral point 44 of the stator winding 40. For each of the phase windings 41, the first section (a) is accommodated in different single-phase slots 31 for the phase winding 41 opposite the 2nth section (i.e., the fourth section (d) in the present embodiment).

[0064] With the above setup, the negative mutual inductance between the first and the nth sections can be minimized, thereby minimizing the decrease in the overall inductance of the stator winding 40 due to the negative mutual inductance. Consequently, as in Fig. As shown in Figure 7, it is possible to significantly reduce both the resonant frequency and the resonant peak of the stator winding 40 compared to the conventional design, as described in Figure 7. Fig. Figure 27A illustrates this. This makes it possible to reduce the maximum phase-to-phase voltage of the stator winding 40, thereby shortening the necessary phase-to-phase gap of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40. Additionally, the resonant frequency f n The stator winding 40 can be determined by the following equation: fn=1 / 2πLC where L is the total inductance of the stator winding 40 and C is the ground capacitance between the stator winding 40 and the stator core 30. Furthermore, the total inductance L of the stator winding 40 is the sum of the self-inductance of the stator winding 40 and the mutual inductances between different sections of the stator winding 40. By minimizing the negative mutual inductances between the first and the 2nth section in each phase winding 41 of the stator winding 40, it is therefore possible to minimize the decrease in the total inductance L of the stator winding 40 due to the negative mutual inductances.

[0065] In the present embodiment, for each of the phase windings 41 of the stator winding 40, the 2m-th section of the phase winding 41 is accommodated in the same single-phase slots 31 for the phase winding 41 as the (2m-1)-th section of the phase winding 41, where m is a natural number that satisfies the condition 1 ≤ m ≤ n. For example, for the U-phase winding 41, the first and second sections (a) and (b) are accommodated in the same single-phase slots U1, while the third and fourth sections (c) and (d) are accommodated in the same single-phase slots U2.

[0066] Consequently, it is possible to minimize the negative mutual inductances between the first and third sections (a) and (c) and between the second and fourth sections (b) and (d), thereby further reducing both the resonant frequency and the resonant peak of the stator winding 40. As a result, it is possible to further reduce the maximum phase-to-phase voltage of the stator winding 40, thereby further shortening the necessary phase-to-phase spacing of the stator winding 40 to ensure electrical insulation between the phase windings 41.

[0067] In the present embodiment, for each of the phase windings 41 of the stator winding 40, the first to 2nth sections of the phase winding 41 are wound as a wave winding onto the stator core 30.

[0068] The above design allows for the simple fabrication of the stator winding 40. Furthermore, it reliably achieves the effect of reducing both the resonant frequency and the peak frequency of the stator winding 40.

[0069] In the present embodiment, each of the phase windings 41 of the stator winding 40 is formed from essentially U-shaped electrical conductor segments 50, each of which is inserted into the corresponding single-phase slots 31 for the phase winding 41 and is electrically connected in series. On one axial side of the stator core 30, corresponding pairs of the sections 51 of the electrical conductor segments 50 located in the slot are connected by a bent section 52. On the other axial side of the stator core 30, corresponding pairs of the inclined parts 55 of the electrical conductor segments 50 are connected to each other to form the connection 56 between them.All of the bending sections 52, which connect the sections 51 of the electrical conductor segments 50 of the phase winding 41 located in the slot, together form the first coil head 47 of the stator winding 40 on one axial side of the stator core 30. All of the inclined parts 55 of the electrical conductor segments 50 of the phase winding 41 and the connections 56 made between the inclined parts 55 together form the second coil head 48 of the stator winding 40 on the other axial side of the stator core 30.

[0070] With the above design, since each of the conductor segments 50 can be made short and thus easy to handle, it is possible to manufacture the stator winding 40 more easily compared to manufacturing each of the phase windings 41 of the stator winding 40 from a single continuous electrical wire. In the present embodiment, the maximum voltage applied between the terminals 43 of the phase windings 41 of the stator winding 40 is set to be greater than or equal to 330 V.

[0071] In detail, as in Fig. As shown in Figure 6, according to Paschen's law, in the range where the discharge initiation voltage is not lower than approximately 330 V, the discharge initiation voltage has a positive relationship to the distance between the electrical conductors. Accordingly, in this range, the necessary phase-to-phase spacing of the stator winding 40 to ensure electrical insulation between the phase windings 41 also has a positive correlation with the maximum phase-to-phase voltage of the stator winding. Therefore, if the maximum voltage applied between the terminals 43 of the phase windings 41 is set in the manner determined above, it is possible to shorten the necessary phase-to-phase spacing of the stator winding 40 by reducing the maximum phase-to-phase voltage of the stator winding 40. [Attempt 1]

[0072] This experiment was conducted to determine the effect of reducing the maximum phase-to-phase voltage of the stator winding 40 according to the first embodiment. Specifically, a rotating electric machine was used in the experiment, in which the stator core had two single-phase slots, one for each phase winding of the stator winding and one for each magnetic pole of the rotor. The phase windings of the stator winding were wound as wave windings on the stator core such that they were stacked radially in six layers in each slot of the stator core. Furthermore, three different stator configurations were achieved in the rotating electric machine by changing the sequence of electrical connections of different sections of the phase windings of the stator winding.

[0073] The first configuration was of the conventional type, as seen in Fig. 27A is shown. The second configuration was of a conventional type, as shown in Fig. 28A. In both the first and second conventional configurations, the first section (a) and the fourth section (d) for each phase winding of the stator winding were accommodated in the same single-phase slots, as specified in patent document 1. On the other hand, the third configuration was that according to the first embodiment and of a type as shown in Fig. 8b is shown.

[0074] In each of the three configurations, as described in Fig. Figure 8A shows the phase-to-phase voltage between the phase windings 41 measured at positions where the degree of resonance is high (for example, at about a point on a quarter of the length of the respective terminal 43 in the phase windings 41).

[0075] The measurement results of the experiment are in Fig. Figure 9 is shown, in which the abscissa represents time and the ordinate represents the voltage from phase to phase. Additionally, in Fig. 9 the inscription “applied voltage” means the voltage applied between the terminals 43 of the phase windings 41; the inscription “first conventional embodiment” means the first setup according to the prior art; “first embodiment” means a setup according to the first embodiment; and the inscription “second conventional setup” means the second setup according to the prior art.

[0076] As in Fig. As shown in Figure 9, in the first embodiment, the phase-to-phase voltage fluctuation due to resonance was considerably reduced compared to the first and second conventional designs. Furthermore, in the first embodiment, the maximum phase-to-phase voltage was reduced by approximately 18% relative to the voltage applied between the terminals 43 of the phase winding 41. In contrast, in the first and second prior art designs, the maximum phase-to-phase voltage exceeded the voltage applied between the terminals 43 of the phase winding 41. [First modification]

[0077] In this modification, as in the Fig. 10A and Fig. As shown in Figure 10B, each of the phase windings 41 of the stator winding 40 is formed by connection through eight continuous electrical wires 60, rather than by connection of the electrical conductor segments 50, as in the first embodiment.

[0078] Specifically, each of the electrical wires 60 contains twelve slots (not shown), each of which fits into a corresponding slot 31 of the stator core 30, as well as eleven bending sections 62, each connecting a corresponding adjacent pair of slots and alternately located on opposite axial sides of the stator core 30. Furthermore, of the twelve slots, the first slot, formed at one end of the electrical conductor wire 60, fits into the first layer (i.e., the radially innermost layer) of a slot 31 of the stator core 30, while the twelfth slot, formed at the other end of the electrical wire 60, fits into the sixth layer (i.e., the radially outermost layer) of another slot 31 of the stator core 30.Each of the electrical wires 60 is wound around the stator core 30 as a wave winding, for example in eleven / eight turns.

[0079] Furthermore, in this modification, each of the phase windings 41 of the stator winding 40, as in the first embodiment, contains four sections (i.e., 2n sections, where n equals 2). The first to fourth sections (a) to (d) are arranged sequentially from one end of the phase winding 41 to the other end of the phase winding 41. The first section (a) is accommodated in different single-phase slots 31 for the phase winding 41 compared to the fourth section (d). Furthermore, the first and second sections (a) and (b) are accommodated in the same single-phase slots 31 for the phase winding 41, while the third and fourth sections (c) and (d) are accommodated in the same single-phase slots 31 for the phase winding 41. Each of the first to fourth sections (a) to (d) is wound as a wave winding on the stator core 30.

[0080] With the above setup according to the present modification, it is also possible to significantly lower both the resonant frequency and the resonant peak of the stator winding 40. Consequently, it is possible to reduce the maximum phase-to-phase voltage of the stator winding 40, thereby shortening the necessary phase-to-phase spacing of the stator winding 40, which ensures electrical insulation between the phase windings 41 of the stator winding 40. [Second modification]

[0081] In this modification, as in the Fig. As shown in Figures 11A to 11C, each of the phase windings 41 of the stator winding 40 is formed by connecting a number of substantially U-shaped electrical conductor segments 50, as in the first embodiment. However, each of the phase windings 41 is wound on the stator core 30 as a loop winding and not, as in the first embodiment, as a wave winding on the stator core 30.

[0082] In the present modification, each of the phase windings 41 is wound around the stator core 30 as a loop winding to provide a number of sections located in the slot, pairs of which are accommodated in a corresponding single-phase slot 31 for the phase winding 41, so that the two sections of the pair located in the slot lie on top of each other in the corresponding single-phase slot 31.

[0083] Furthermore, in the present modification, each of the phase windings 41 of the stator winding 40, as in the first embodiment, contains four sections (i.e., 2n sections, where n equals 2). The first to fourth sections (a) to (d) are arranged sequentially from one end of the phase winding 41 to the other end of the phase winding 41. The first section (a) is accommodated in different single-phase slots 31 for the phase winding 41 opposite the fourth section (d). Furthermore, the first and second sections (a) and (b) are accommodated in the same single-phase slots 31 for the phase winding 41, while the third and fourth sections (c) and (d) are again accommodated in the same single-phase slots 31 for the phase winding 41.

[0084] With the above configuration according to the aforementioned modification, it is also possible to significantly reduce both the resonant frequency and the resonant peak of the stator winding 40. Consequently, it is possible to lower the maximum phase-to-phase voltage of the stator winding 40 and thereby shorten the necessary phase-to-phase distance of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40. [Second embodiment]

[0085] This embodiment shows a stator 20 which has a similar structure to the stator 20 according to the first embodiment; accordingly, only the differences between the embodiments are described below.

[0086] In the present embodiment, as in Fig. Figure 12 shows that each of the phase windings 41 of the stator winding 40 consists of j sub-windings 42, which are connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40, where j is a natural number greater than or equal to 2. Furthermore, each of the sub-windings 42 contains k sections, which are arranged in series from one end of the sub-winding 42 on the terminal 43 side to the other end of the sub-winding 42 on the neutral point 44 side, where k is a natural number greater than or equal to 2. Furthermore, for each of the sub-windings 42, the first to (k / 2)th sections of the sub-winding 42 are accommodated in various of the single-phase slots 31 for the phase winding 41 opposite the (k / 2+1)th to kth sections of the sub-winding 42.

[0087] Specifically, let us assume that j equals 2 and k equals 4. Then, as in Fig. As shown in Figure 12, each of the phase windings 41 of the stator winding 40 consists of a first sub-winding 42-1 and a second sub-winding 42-2, which are connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40. The first sub-winding 42-1 contains a first section (1a), a second section (1b), a third section (1c), and a fourth section (1d), which are arranged sequentially from one end of the first sub-winding 42-1 on the terminal 43 side to the other end of the first sub-winding 42-1 on the neutral point 44 side.The second sub-winding 42-2 contains a first section (2a), a second section (2b), a third section (2c) and a fourth section (2d), which are arranged sequentially from one end of the second sub-winding 42-2 on the side of the terminal 43 to the other end of the second sub-winding 42-2 on the side of the neutral point 44.

[0088] Furthermore, as in Fig. Figure 13 shows that for each of the phase windings 41 the first and second sections (1a), (1b), (2a), (2b) of the first and second sub-windings 42-1 and 42-2 are inserted into different single-phase slots 31 for the phase winding 41 opposite the third and fourth sections (1c, 1d, 2c, 2d) of the first and second sub-windings 42-1 and 42-2.

[0089] Additionally, it should be noted that, for the sake of simplicity, only the positions of the sections of the underwindings of the U-phase winding 41 in the single-phase slots 31 for the U-phase winding 41 are shown. Fig. 13 are shown; and that the sections of the underwindings of the V-phase winding 41 and the W-phase winding 41 are each positioned in the single-phase slots 31 for the V-phase winding 41 and the W-phase winding 41 respectively in the same way as those of the U-phase winding 41.

[0090] In the above configuration of the stator 20 according to the present embodiment, it is possible for each phase winding 41 of the stator winding 40 to weaken the magnetic coupling between the first and second sections (1a, 1b, 2a, 2b) and the third and fourth sections (1c, 1d, 2c, 2d) of the first and second sub-windings 42-1 and 42-2 of the phase winding 41, thereby minimizing the negative mutual inductances between them. Consequently, it is possible to reduce the decrease in the overall inductance of the stator winding 40 due to the negative mutual inductances, thereby lowering both the resonant frequency and the resonant peak of the stator winding 40.As a result, it is possible to reduce the maximum phase-to-phase voltage of the stator winding 40, thereby shortening the necessary phase-to-phase distance of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40.

[0091] In the case where k is an odd number greater than 2, the central section of each of the sub-windings 42-1 and 42-2 can additionally be accommodated either in the same single-phase slots 31 as those sections of the sub-winding which are located upstream (i.e., on the side of terminal 43) from the central section, or can be accommodated in the same single-phase slots 31 as those sections of the sub-winding which are located downstream (i.e., on the side of neutral point 44) from the central section. [Third embodiment]

[0092] This embodiment shows a stator 20 which has a similar structure to the stator 20 according to the first embodiment; accordingly, only the differences between the embodiments are described below.

[0093] In this embodiment, as in the Fig. 14 and Fig. As shown in Figure 15, each of the phase windings 41 of the stator winding 40 has k sections arranged sequentially from one end of the phase winding 41 on the terminal 43 side to the other end of the phase winding 41 on the neutral point 44 side, where k is a natural number greater than or equal to 2. Furthermore, each of the k sections is wound on the stator core 30 such that the circumferential direction of the section reverses for each completion of a circumferential advance of 360° / k (i.e., one advance in the circumferential direction of the stator core 30 corresponding to a mechanical angular range of 360°). 0 / k).

[0094] Specifically, let us assume that k = 2. Then, as in Fig. As shown in Figure 14, each of the phase windings 41 of the stator winding 40 has a first section (a) on the terminal 43 side and a second section (b) on the neutral point 44 side. Furthermore, each of the first and second sections (a) and (b) is wound on the stator 30 in such a way that the circumferential direction of the section reverses each time the section makes a circumferential advance of 180° around the stator core 30. 0 has completed.

[0095] More precisely, as in Fig. As shown in Figure 15, for each of the phase windings 41, the first section (a) of the phase winding 41 is initially wound as a two-layer loop winding onto the stator core 30, such that it is wound clockwise (i.e. in Fig. 15 to the right) in the circumferential direction of the stator core 30 from a first slot 31 (not shown) to a second slot 31 (not shown) of the stator core 30. The first slot 31 has a circumferential position corresponding to a mechanical angle of 0° (or 360°), while the second slot 31 has a circumferential position corresponding to a mechanical angle of 180°. This means that the first section (a) first advances clockwise in the circumferential direction of the stator core 30 by 180°. Consequently, as in Fig. As shown in solid line 15, a first part (a1) of the first section (a) is received in two layers in each of the slots 31 whose circumferential positions fall within the range of 0° to 180°. Then the first section (a) is wound as a two-layer loop winding onto the stator core 30 such that it is wound counterclockwise (i.e., in Fig. 15 to the left) from the second groove 31 to the first groove 31. This means that the circumferential direction of advance of the first section (a) reverses at the second groove 31 and the first section (a) continues counterclockwise in the circumferential direction of the stator core 30 by 180°. Consequently, as in Fig. 15 shown by broken lines, a second part (a2) of the first section (a) also receives in two layers in each of those grooves 31 whose circumferential positions fall within the range of 0° to 180°.

[0096] Furthermore, the second section (b) of the phase winding 41 is first wound as a two-layer loop winding onto the stator core 30 such that it progresses counterclockwise from the first slot 31 to the second slot 31. This means that the second section (b) first progresses counterclockwise around the circumference of the stator core 30 by 180°. Consequently, as in Fig. As shown in Figure 15 by a dashed line, a first part (b1) of the second section (b) is received in two layers in each of those slots 31 whose circumferential positions fall within the range of 180° to 360°. Then the second section (b) is wound as a two-layer loop winding onto the stator core 30 such that it progresses clockwise from the second slot 31 to the first slot 31. This means that the circumferential direction of progress of the second section (b) reverses at the second slot 31 and the second section (b) continues to progress clockwise in the circumferential direction of the stator core 30 by 180°. Consequently, as in Fig. 15 shown by a solid line, a second part (b2) of the second section (b) also receives in two layers in each of those grooves 31 whose circumferential positions fall within the range of 180° to 360°.

[0097] In addition, in the present embodiment, the circumferential direction of each of the first and second sections (a) and (b) of the phase windings 41 reverses only once, and thus the section contains only the first and second parts. It should be noted, however, that the circumferential direction of the section can also be reversed multiple times, and thus the section can contain three or more parts.

[0098] With the above-mentioned construction of the stator 20 according to the present embodiment, the first section (a) of each phase winding 41 of the stator winding 40 can be separately accommodated in different single-phase slots 31 for the phase winding 41 relative to the second section (b) of the phase winding 41. Consequently, it is possible to weaken the magnetic coupling between the first section (a) and the second section (b) of the phase winding 41 and thereby minimize the negative mutual inductance between the sections. It is therefore possible to reduce the decrease in the overall inductance of the stator winding 40 due to the negative mutual inductances and thereby lower both the resonant frequency and the resonant peak of the stator winding 40.Therefore, it is possible to reduce the maximum phase-to-phase voltage of the stator winding 40 and thereby shorten the necessary phase-to-phase distance of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40. [Comparative example of the third embodiment]

[0099] In this comparative example, for each of the phase windings 41 of the stator winding 40, each of the k sections of the phase winding 41 is wound onto the stator core 30 in a manner different from the third embodiment.

[0100] In detail, as in Fig. As shown in Figure 16, for each of the phase windings 41, the first section (a) of the phase winding 41 is initially wound as a two-layer loop winding onto the stator core 30 with one complete turn, so that it is wound clockwise (i.e., in Fig. 6 to the right) progresses 360° circumferentially around the stator core 30. This means that the first section (a) is wound onto the stator core 30 without reversing its circumferential direction of progress. Then the second section (b) of the phase winding 41 is wound as a two-layer loop winding onto the stator core 30 with one complete turn, such that it proceeds counterclockwise (i.e., in the direction of rotation). Fig. 16 to the left) progresses 360° in the circumferential direction of the stator core 30. This means that the second section (b) is also wound onto the stator core 30 without reversing its circumferential direction of progress.

[0101] Consequently, as in Fig. As shown by a solid line in Figure 16, the first section (a) is taken up in two layers in each of those grooves 31 whose circumferential positions fall within the range of 0° to 360°. Furthermore, as shown in Figure 16, the first section (a) is taken up in two layers in each of those grooves 31 whose circumferential positions fall within the range of 0° to 360°. In addition, as shown in Figure 16, the first section (a) is taken up in Fig. As shown by a dashed line in Figure 16, the second section (b) is also received in two layers in each of those grooves 31 whose circumferential positions fall within the range of 0° to 360°. Furthermore, the first part (a1) of the first section (a) and the second part (b2) of the second section (b) are received in the same grooves 31 whose circumferential positions fall within the range of 0° to 180°; the second part (a2) of the first section (a) and the first part (b1) of the second section (b) are received in the same grooves 31 whose circumferential positions fall within the range of 180° to 360°.

[0102] Consequently, in the comparative example, for each of the phase windings 41 of the stator winding 40, the first section (a) of the phase winding 41 is accommodated in the same single-phase slots 31 for the phase winding 41 as the second section (b) of the phase winding 41. Consequently, it is not possible to achieve the same advantages as with the stator 20 according to the third embodiment. [Fourth embodiment]

[0103] This embodiment shows a stator 20 which has a similar structure to the stator 20 according to the first embodiment; accordingly, only the differences between them are described below.

[0104] In the present embodiment, as in the second embodiment (see Fig. 12) Each of the phase windings 41 of the stator winding 40 has j sub-windings 42 connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40, where j is a natural number greater than or equal to 2. Furthermore, each of the sub-windings 42 contains k sections arranged sequentially from one end of the sub-winding 42 on the terminal 43 side to the other end of the sub-winding 42 on the neutral point 44 side, where k is a natural number greater than or equal to 2. Furthermore, in the present embodiment, when counting from one end of the phase winding 41 on the side of the terminal 43, the sections of the sub-windings 42 of the phase winding 41 with the same numbers are accommodated in the same single-phase slots 31 for the phase winding 41, so that they are adjacent to each other in the same single-phase slots 31.

[0105] Specifically, let us assume that j equals 2 and k equals 4. Then, and here we again refer to Fig. 12. Referring to, each of the phase windings 41 of the stator winding 40 consists of a first sub-winding 42-1 and a second sub-winding 42-2, which are connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40. The first sub-winding 42-1 contains a first section (1a), a second section (1b), a third section (1c), and a fourth section (1d), which are arranged sequentially from one end of the first sub-winding 42-1 on the terminal 43 side to the other end of the first sub-winding 42-1 on the neutral point 44 side.The second sub-winding 42-2 contains a first section (2a), a second section (2b), a third section (2c) and a fourth section (2d), which are arranged sequentially from one end of the second sub-winding 42-2 on the side of the terminal 43 to the other end of the second sub-winding 42-2 on the side of the neutral point 44.

[0106] Furthermore, as in Fig. As shown in Figure 17, for each of the phase windings 41, the first sections (1a, 2a) of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they lie close together in the same single-phase slots 31. The second sections (1b, 2b) of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they are adjacent to each other in the same single-phase slots 31. The third sections (1c, 2c) of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they lie close together in the same single-phase slots 31.The fourth sections (1d, 2d) of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they lie close together in the same single-phase slots 31. More precisely, in the present embodiment, in each of the single-phase slots 31 for the phase winding 41, all the sections of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 are arranged radially from the radially outer side in the sequence 1a, 2a, 1b, 2b, 1c, 2c, 1d, 2d or in the sequence 2a, 1a, 2b, 1b, 2c, 1c, 2d, 1d.

[0107] With the arrangement described above for the first sub-winding 42-1, the first and second sections (1a, 1b) are radially separated from the third and fourth sections (1c, 1d), thereby weakening the magnetic coupling between the first and second sections (1a, 1b) and the third and fourth sections (1c, 1d). Similarly, for the second sub-winding 42-2, the first and second sections (2a, 2b) are radially separated from the third and fourth sections (2c, 2d), thereby weakening the magnetic coupling between the first and second sections (2a, 2b) and the third and fourth sections (2c, 2d).Consequently, it is possible to minimize the decrease in the overall inductance of the stator winding 40 due to the negative mutual inductance between the first and second sections (1a, 1b) and the third and fourth sections (1c, 1d) of the first sub-winding 42-1 and between the first and second sections (2a, 2b) and the third and fourth sections (2c, 2d) of the second sub-winding 42-2, thereby reducing both the resonant frequency and the resonant peak of the stator winding 40. As a result, it is possible to lower the maximum phase-to-phase voltage of the stator winding 40, thus shortening the required phase-to-phase distance of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40.

[0108] In addition, for each of the phase windings 41 of the stator winding 40, all of the sections of the first and second sub-windings 42-1 and 42-2 of the phase winding 41 can also be arranged radially from the radial outside in different sequences, for example in the sequence of 1a, 1b, 2a, 2b, 1c, 1d, 2c, 2d in each of the single-phase slots 31 for the phase winding 41. [Fifth embodiment]

[0109] In the present embodiment, as in the fourth embodiment, for each of the phase windings 41 of the stator winding 40, when counting from one end of the phase winding 41, the equally numbered sections of the sub-phase winding 42 of the phase winding 41 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they are located close to each other in the same single-phase slots 31.

[0110] Furthermore, in the present embodiment, for each of the sub-windings 42, the first to (k / 2)th sections of the sub-winding 42 are accommodated in different of the single-phase slots 31 for the phase winding 41 opposite the (k / 2+1)th to kth sections of the sub-winding 42.

[0111] Specifically, let us assume that j equals 2 and k equals 4, as in the fourth embodiment. Then, as in Fig. As shown in Figure 18, for each of the phase windings 41 of the stator winding 40, the first sections (1a, 2a) of the first and second sub-windings 42-1 and 42-2 are inserted into the same single-phase slots 31 for the phase winding 41, so that they are located close to each other in the same single-phase slots 31. The second sections (1b, 2b) of the first and second sub-windings 42-1 and 42-2 are inserted into the same single-phase slots 31 for the phase winding 41, so that they are located adjacent to each other in the same single-phase slots 31. The third sections (1c, 2c) of the first and second sub-windings 42-1 and 42-2 are inserted into the same single-phase slots 31 for the phase winding 41, so that they are located adjacent to each other in the same single-phase slots 31.The fourth sections (1d, 2d) of the first and second sub-windings 42-1 and 42-2 are accommodated in the same single-phase slots 31 for the phase winding 41, so that they lie adjacent to each other in the same single-phase slots 31.

[0112] Furthermore, in the present embodiment, for each of the phase windings 41 of the stator winding 40, the first and second sections (1a, 1b, 2a, 2b) of the first and second sub-windings 42-1 and 42-2 are accommodated in different single-phase slots 31 for the phase winding 41 opposite the third and fourth sections (1c, 1d, 2c, 2d) of the first and second sub-windings 42-1 and 42-2. More precisely, in one of the single-phase slots 31 for the phase winding 41, the first and second sections (1a, 1b, 2a, 2b) of the first and second sub-windings 42-1 and 42-2 are arranged radially from the outside in the sequence 1a, 2a, 1a, 2a, 1b, 2b, 1b, 2b. In another of the single-phase slots 31 for the phase winding 41, the third and fourth sections (1c, 1d, 2c, 2d) of the first and second sub-windings 42-1 and 42-2 are arranged radially from the radial outside in the sequence of 1c, 2c, 1c, 2c, 1d, 2d, 1d, 2d.

[0113] With this construction of the stator 20 according to the present embodiment, it is possible, since the first and second sections (1a, 1b, 2a, 2b) of the first and second sub-windings 42-1 and 42-2 are accommodated in different single-phase slots 31 for the phase winding 41 compared to the third and fourth sections (1c, 1d, 2c, 2d) of the first and second sub-windings 42-1 and 42-2, to weaken the magnetic coupling between the first and second sections (1a, 1b, 2a, 2b) and the third and fourth sections (1c, 1d, 2c, 2d).Furthermore, since the identically numbered sections of the first and second underwindings 42-1 and 42-2 are accommodated in the same single-phase grooves 31, so that they are close together, all sections of the underwindings 42 can be arranged such that: the first and second sections (1a, 1b) of the first underwinding 42-1 are radially spaced apart from each other; the third and fourth sections (1c, 1d) of the first underwinding 42-1 are radially separated from each other; the first and second sections (2a, 2b) of the second underwinding 42-2 are radially separated from each other; and the third and fourth sections (2c, 2d) of the second underwinding 42-2 are radially separated from each other. Consequently, it is possible to weaken the magnetic coupling between the sections (1a to 1d) of the first sub-winding 42-1 and between the sections (2a to 2d) of the second sub-winding 42-2.Thus, it is possible to minimize the decrease in the overall inductance of the stator winding 40 due to the negative mutual inductances between the sections (1a to 1d, 2a to 2d) of the sub-windings 42 of the phase winding 41, thereby lowering both the resonant frequency and the resonant peak of the stator winding 40. Consequently, it is possible to reduce the maximum phase-to-phase voltage of the stator winding 40, so that the necessary phase-to-phase spacing of the stator winding to ensure electrical insulation between the phase windings of the stator winding 40 can be shortened.

[0114] Additionally, in the present embodiment, if k is an odd number greater than 3, the central section of each of the sub-windings 42 can be received either in the same single-phase slots 31 as those sections of the sub-winding 42 which are located upstream (i.e., on the side of the terminal 43) of the central section, or in the same single-phase slots 31 as those sections of the sub-winding 42 which are located downstream (i.e., on the side of the neutral point 44) of the central section. [Sixth embodiment]

[0115] This embodiment provides a stator 20 which has a similar structure to the stator 20 according to the first embodiment; accordingly, only the differences between the embodiments are described below.

[0116] In the present embodiment, the stator core 30 has 2j consecutive single-phase slots 31 for each of the phase windings 41 of the stator winding 40, in which only the phase winding 41 is accommodated, at each magnetic pole of the rotor 14, where j is a natural number greater than or equal to 2. Furthermore, each of the phase windings 41 of the stator winding 40 consists of j sub-windings 42, which are connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40. Each sub-winding 42 further consists of a first half on the terminal 43 side and a second half on the neutral point 44 side. Each of the single-phase slots 31 for the phase winding 41 accommodates only one corresponding half of the first and second half of the sub-winding 42 of the phase winding 41.

[0117] Specifically, let us assume that j equals 2. Then, as in the Fig. 19 and Fig. As shown in Figure 20, the stator core 30 has four circumferentially consecutive single-phase slots 31 for each of the phase windings 41 of the stator winding 40, one for each magnetic pole of the rotor 14. Accordingly, the total number of slots 31 provided in the stator core 30 is 96 (i.e., four x three x eight). Furthermore, each of the phase windings 41 of the stator winding 40 consists of two sub-windings 42, i.e., a first sub-winding 42-1 and a second sub-winding 42-2, which are connected in parallel to each other between the terminal 43 of the phase winding 41 and the neutral point 44 of the stator winding 40. The first sub-winding 42-1 contains a first section (1a), a second section (1b), a third section (1c) and a fourth section (1d), which are arranged sequentially from one end of the first sub-winding 42-1 on the side of the terminal 43 to the other end of the first sub-winding 42-1 on the side of the neutral point 44.The second sub-winding 42-2 contains a first section (2a), a second section (2b), a third section (2c) and a fourth section (2d), which are arranged sequentially from one end of the second sub-winding 42-2 on the side of the terminal 43 to the other end of the second sub-winding 42-2 on the side of the neutral point 44.

[0118] Furthermore, and here the U-phase winding 41 is considered as an example, it is found, as in Fig. As shown in Figure 20, the first half of the second sub-winding 42-2, which consists of the first and second sections (2a, 2b) of the second sub-winding 42-2, is inserted into the single-phase slot U1. The second half of the second sub-winding 42-2, which consists of the third and fourth sections (2c, 2d) of the second sub-winding 42-2, is inserted into the single-phase slot U2. The first half of the first sub-winding 42-1, which consists of the first and second sections (1a, 1b) of the first sub-winding 42-1, is inserted into the single-phase slot U3. The second half of the first sub-winding 42-1, which consists of the third and fourth sections (1c, 1d) of the first sub-winding 42-1, is inserted into the single-phase slot U4.

[0119] This means that in the present embodiment, all of the first and second halves of the first and second sub-windings 42-1 and 42-2 of the U-phase winding 41 are arranged separately from each other in different single-phase slots U1 to U4 for the phase winding 41.

[0120] In addition, in the present embodiment, the first and second sections (2a, 2b) of the second underwinding 42-2 are arranged alternately in eight layers in each of the single-phase slots U1. In each of the single-phase slots U2, the third and fourth sections (2c, 2d) of the second underwinding 42-2 are arranged alternately in eight layers. In each of the single-phase slots U3, the first and second sections (1a, 1b) of the first underwinding 42-1 are arranged alternately in eight layers. In each of the single-phase slots U4, the third and fourth sections (1c, 1d) of the first underwinding 42-1 are arranged alternately in eight layers.

[0121] Furthermore, as in Fig. As shown in Figure 21, the difference in electrical angle between the first half of the second underwinding 42-2, which is inserted into the single-phase slots U1, and the first half of the first underwinding 42-1, which is inserted into the single-phase slots U3, is 30°. The difference in electrical angle between the second half of the second underwinding 42-2, which is inserted into the single-phase slots U2, and the second half of the first underwinding 42-1, which is inserted into the single-phase slots U4, is also 30°.

[0122] This means that in the present embodiment, the first and second sub-windings 42-1 and 42-2 are wound onto the stator core 30 in such a way that they are offset from each other circumferentially by 30° of the electrical angle.

[0123] Additionally, it should be noted that the first and second halves of the under-windings 42 of the V-phase winding and W-phase winding 41 are arranged in the single-phase slots 31 for the V-phase winding and the W-phase winding 41 in the same way as those of the U-phase winding 41.

[0124] With the above-mentioned construction of the stator 20 according to the present embodiment, it is possible for each of the sub-windings 42 of the phase windings 41 of the stator winding 40 to weaken the magnetic coupling between the first and second halves of the sub-winding 42 and thereby keep the negative mutual inductance between them to a minimum. Consequently, it is possible to minimize the decrease in the total inductance of the stator winding 40 due to the negative mutual inductance, thereby lowering both the resonant frequency and the resonant peak of the stator winding 40. As a result, it is possible to reduce the maximum phase-to-phase voltage of the stator winding 40, thereby shortening the necessary phase-to-phase distance of the stator winding 40 to ensure electrical insulation between the phase windings 41 of the stator winding 40.

[0125] Furthermore, since the sub-windings 42 are circumferentially offset from each other by an electrical angle of 30° (i.e., 60° / j, where j is equal to 2) in each of the phase windings 41 of the stator winding 40, it is possible to reduce the change in the magnetomotive force in the circumferential direction of the stator core 30, thereby lowering the level of magnetic disturbance in the stator 20.

[0126] Furthermore, it is possible to modify the stator 20 of the present embodiment such that each of the phase windings 41 of the stator winding 40 is formed by connecting a given number of continuous electrical wires, instead of connecting U-shaped electrical conductor segments 50. Thus, it is possible to modify the stator 20 according to the present embodiment such that each of the phase windings 41 is wound as a loop winding around the stator core 30, instead of as a wave winding around the stator core 30. [Attempt 2]

[0127] This test was carried out to determine the effect of reducing magnetic noise or magnetic interference according to the sixth embodiment.

[0128] In detail, the test examined both the stator 20 according to the sixth embodiment and the stator 20 according to a comparative example.

[0129] In the stator 20 according to the comparative example, as in Fig. As shown in Figure 22, the stator core 30 has only one single-phase slot per magnetic pole of the rotor 14 for each of the phase windings 41 of the stator winding 40. Furthermore, each of the phase windings 41 does not consist of parallel-connected sub-windings as in the sixth embodiment.

[0130] Fig. Figure 23 shows the distribution of the magnetomotive force in the stator 20 according to the sixth embodiment, where the distribution was measured in the experiment. On the other hand, Figure 23 shows... Fig. 24 the distribution of the magnetomotive force in the stator 20 according to the comparative example, which was also measured in the experiment.

[0131] As from the Fig. 23 and Fig. As can be seen in Figure 24, the magnetomotive force of both stators 20 changed with a 30° cycle of the electrical angle. The magnitude of the change in the magnetomotive force reaches a maximum when the electrical angle is changed from 0° to 30°. Additionally, the magnitude of the change in the magnetomotive force is greater the higher the level of magnetic noise or magnetic disturbance induced in the rotating electrical machine.

[0132] Fig. Figure 25 enables a comparison of the magnetic noise level between the stator 20 according to the sixth embodiment and the stator 20 according to the comparative example. Here, the magnetic noise level was obtained by integrating the magnitude of the change in the magnetomotive force for the range of the electric angle from 0° to 60°.

[0133] One can from Fig. 25 recognize that the magnetic noise level in the stator 20 according to the sixth embodiment has been reduced to less than half the magnetic noise level in the stator 20 according to the comparative example.

[0134] While the above particular embodiments have been presented and described, it is understood by those skilled in the art that many modifications, changes and improvements can be made without abandoning the basic idea of ​​the invention.

[0135] For example, in the first embodiment, each of the U-phase winding, V-phase winding, and W-phase winding 41 of the stator winding 40 is configured to contain 2n sections, where n is a natural number greater than or equal to 2. However, each of the U-, V-, and W-phase windings 41 of the stator winding 40 can also be configured to contain k sections, where k is a natural number greater than or equal to 2. Furthermore, in the first embodiment, the U-shaped electrical conductor segments 50 are used to form the stator winding 40. However, electrical conductor segments of other shapes (for example, substantially I-shaped electrical conductor segments) can also be used instead of the substantially U-shaped electrical conductor segments 50 to form the stator winding 40.

[0136] In the embodiments described above, the invention relates to a rotating electrical machine 1, which is designed to operate as an electric motor. However, the invention can also be applied to other rotating electrical machines, for example, an electric generator or a motor-generator that can operate both as an electric motor and as an electric generator.

Claims

[1] Rotating electrical machine (1) comprising the following: a rotor (14) which has a number of pairs of magnetic poles arranged in the circumferential direction of the rotor; and a stator (20) comprising a stator core (30) and a stator winding (40), wherein the stator core has a number of slots (31) arranged in a circumferential direction of the stator core and radially opposite the rotor, wherein the stator winding consists of a number of phase windings (41), each of which is wound onto the stator core such that it is inserted into corresponding slots of the stator core; wherein the stator core has circumferentially successive single-phase slots for each of the phase windings of the stator winding n, in which only the phase winding is accommodated, for each magnetic pole of the rotor, wherein n is a natural number greater than or equal to 2; Each of the phase windings of the stator winding has k sections, which contain a first section and a k-th section, where k is a natural number greater than or equal to 2; the first to k-th sections are arranged sequentially from one end to the other end of the phase winding; and the first section is accommodated in a different single-phase slot for the phase winding than the k-th section, and whereby Each of the phase windings of the stator winding consists of a plurality of electrical conductor segments (50) which are inserted into the single-phase slots for the phase winding and are electrically connected in series with each other, on an axial side of the stator core, each corresponding pair of sections of the electrical conductor segments located in the slot, which are accommodated in the single-phase slots for the phase winding, are connected by a bending section (52), On the other axial side of the stator core, each corresponding pair of end parts of the electrical conductor segments is connected to each other in order to establish a connection between them. all of the bending sections which connect the sections of the electrical conductor segments of the phase windings located in the slot to each other, form a first coil head (47) of the stator winding on one axial side of the stator core, and all end parts of the electrical conductor segments of the phase windings and the connections between the end parts formed a second coil head (48) of the stator winding on the other axial side of the stator core. [2] Rotating electrical machine according to claim 1, wherein k is equal to 2n, such that for each of the phase windings of the stator winding the first section is accommodated in different of the single-phase slots for the phase winding than the 2nth section. [3] Rotating electrical machine according to claim 2, in which for each of the phase windings of the stator winding a 2m-th section of the phase winding is received in the same of the single-phase slots for the phase winding as a (2m-1)-th section of the phase winding, wherein m is a natural number which satisfies the condition 1 ≦ m ≦ n. [4] Rotating electric machine according to claim 1, in which each of the phase windings of the stator winding consists of j sub-windings (42) which are connected in parallel to each other between opposite ends of the phase winding, wherein j is a natural number greater than or equal to 2, Each of the underwindings contains k sections, which are arranged sequentially from one end of the underwinding to the other end of the underwinding, and The first to (k / 2)th sections are accommodated in different single-phase slots for the phase winding than the (k / 2+1)th to kthth sections. [5] Rotating electric machine according to claim 1, in which for each of the phase windings of the stator winding each of the first to k-th sections of the phase winding is wound onto the stator core as a wave winding. [6] Rotating electric machine according to claim 1, in which a maximum voltage applied between the terminals (43) of the phase windings of the stator winding is set such that it is greater than or equal to 330V. [7] Rotating electric machine comprising the following: a rotor; and a stator comprising a stator core and a stator winding, wherein the stator core comprises a number of slots arranged circumferentially to the stator core and radially opposite the rotor, wherein the stator winding consists of a number of phase windings, each of which is wound onto the stator core in such a way that it is inserted into corresponding slots of the stator core; where Each of the phase windings of the stator winding contains k sections, which are arranged in sequence from one end of the phase winding to the other end of the phase winding, wherein k is a natural number greater than or equals 2; and Each of the k sections is wound on the stator core in such a way that the circumferential direction of the section reverses itself with each completion of a circumferential advance of 360° / k, and whereby Each of the phase windings of the stator winding consists of a number of electrical conductor segments which are inserted into the corresponding slots for the phase winding and are electrically connected in series with each other; On an axial side of the stator core, each corresponding pair of sections of the electrical conductor segments located in the slot, which finds a place in the corresponding slots for the phase winding, is connected by a bending section; on the other axial side of the stator core, each corresponding pair of end sections of the electrical conductor segments is connected to each other to establish a connection between them; all of the bending sections that connect the sections of the electrical conductor segments of the phase windings located in the slot together form a first coil head of the stator winding on one axial side of the stator core; and All of the end sections of the electrical conductor segments of the phase windings and the connections made between them together form a second coil head of the stator winding on the other axial side of the stator core. [8] Rotating electric machine according to claim 7, in which for each of the phase windings of the stator winding each of the k sections of the phase winding is wound as a loop winding onto the stator core. [9] Rotating electric machine according to claim 7, in which a maximum voltage applied between terminals of the phase windings of the stator winding is set such that it is greater than or equal to 330V. [10] Rotating electric machine comprising the following: a rotor; and a stator comprising a stator core and a stator winding, wherein the stator core comprises a number of slots arranged in a circumferential direction of the stator core and is radially opposite the rotor, wherein the stator winding consists of a number of phase windings, each of which is wound onto the stator core in such a way that it is inserted into corresponding slots of the stator core; where Each of the phase windings of the stator winding consists of j sub-windings which are connected in parallel to each other between opposite ends of the phase winding, where j is a natural number greater than or equal to 2; Each of the underwindings contains k sections, which are arranged successively from one end of the underwinding to the other end of the underwinding, where k is a natural number greater than or equal to 2; and When counting from one end of the phase winding, sections of the sub-windings of the phase winding bearing the same number are accommodated in the corresponding slots of the phase winding, so that they lie adjacent to each other in the corresponding slots. and whereby Each of the phase windings of the stator winding consists of a number of electrical conductor segments which are inserted into the corresponding slots for the phase winding and are electrically connected in series with each other; On an axial side of the stator core, each corresponding pair of sections of the electrical conductor segments located in the slot, which is accommodated in the corresponding slots of the phase winding, is connected by a bending section; on the other axial side of the stator core, each corresponding pair of end sections of the electrical conductor segments is connected to each other to establish a connection between them; all of the bending sections that connect the sections of the electrical conductor segments of the phase windings located in the slot together form a first coil head of the stator winding on one axial side of the stator core; and all of the end sections of the electrical conductor segments of the phase windings and the connections formed between the end sections form a second coil head of the stator winding on the other axial side of the stator core. [11] Rotating electric machine according to claim 10, in which for each of the sub-windings the first to (k / 2)th sections of the sub-winding are received in other of the corresponding slots of the phase winding than the (k / 2+1)th to kth sections of the sub-winding. [12] Rotating electric machine according to claim 10, in which for each of the phase windings of the stator winding each of the sub-windings of the phase winding is wound as a wave winding onto the stator core. [13] Rotating electric machine according to claim 10, in which a maximum voltage applied between terminals of the phase windings of the stator winding is set to a value higher than or equal to 330V. [14] Rotating electric machine comprising the following: a rotor which has a number of pairs of magnetic poles arranged in the circumferential direction of the rotor; and a stator comprising a stator core and a stator winding, wherein the stator core has a number of slots arranged in a circumferential direction of the stator core and facing the rotor in a radial direction, wherein the stator winding consists of a number of phase windings, each of which is wound onto the stator core in such a way that it is inserted into corresponding slots of the stator core; where the stator core has circumferentially successive single-phase slots for each of the phase windings of the stator winding 2j, in which only the phase winding is accommodated, for each magnetic pole of the rotor, wherein j is a natural number greater than or equal to 2; Each of the phase windings of the stator winding consists of j sub-windings, which are connected in parallel to each other between opposite ends of the phase winding; Each of the sub-windings consists of a first half on the side of one end of the phase winding and a second half on the side of the other end of the phase winding; and For each of the phase windings of the stator winding, all of the first and second halves of the sub-windings of the phase winding are accommodated separately from each other in different of the single-phase slots for the phase winding. [15] Rotating electric machine according to claim 14, in which for each of the phase windings of the stator winding the sub-windings of the phase winding are wound onto the stator core such that they are circumferentially offset from each other by an electrical angle of 60° / j. [16] Rotating electric machine according to claim 14, in which each of the phase windings of the stator winding consists of a number of electrical conductor segments which are inserted into the single-phase slots for the phase winding and are electrically connected in series with each other; on an axial side of the stator core, each corresponding pair of sections of the electrical conductor segments located in the slot, which are accommodated in the single-phase slots for the phase winding, are connected by a bending section; on the other side of the stator core, each corresponding pair of end sections of the electrical conductor segments are connected to each other to create a connection between them; all the bending sections that connect the sections of the electrical conductor segments of the phase windings located in the slot to each other form a first coil head of the stator winding on an axial side of the stator core; and All of the end sections of the electrical conductor segments of the phase windings and the connections formed between the end sections together form a second coil head of the stator winding on the other axial side of the stator core. [17] Rotating electric machine according to claim 14, in which a maximum voltage applied between terminals of the phase windings of the stator winding is set to a value greater than or equal to 330V.

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