Rotary electric machine

Abstract

This rotary electric machine comprises: a multi-phase stator winding that is made up of a stator core in which at least two slots are formed, slot conductors that are inserted into the slots of the stator core and constitute one of a plurality of layers in the slots, and a crossover conductor that constitutes a coil end by connecting the end parts on the same side among the end parts of the slot conductors inserted into different slots, the multi-phase stator winding including a plurality of circulating wave windings; and a rotor that is supported by the stator core in a rotatable manner via a gap, and has two or more poles. The stator winding has a plurality of slot conductor groups constituted by the plurality of slot conductors of the same phase. When the number of slots formed in the stator core is Ns, the number of poles is Np, the number of slots for each pole over which the crossover conductor straddles at one coil end is N1, and the number of slots for each pole over which the crossover conductor straddles at the other coil end is N2, N1 = Ns / Np + 2 and N2 = Ns / Np - 2. The plurality of slot conductors in the slot conductor groups are inserted so that at least some of the slot conductors are adjacent to each other between the slots and between the layers in a predetermined formation number N of slots, said slots of the same phase being continuously arranged in the circumferential direction of the stator core. When NSPP is the number of slots per pole per phase, and 2 × NL is the number of layers formed in one slot, the predetermined number N satisfies N = NSPP + NL + 1.

Description

Rotating electrical machine

[0001] The present invention relates to a rotating electrical machine.

[0002] For example, in Patent Document 1 below, in the stator of a rotating electrical machine, when the number of slots N = 6, the winding wound around the stator straddles slots at a slot pitch of N + 1 (= 7) at one coil end and at a slot pitch of N - 1 (= 5) at the other coil end. When the predetermined number of slots Ns arranged adjacent to each other with respect to the slots and layers in the circumferential direction of the stator core is set to Ns = NSPP + NL (= 4) with the number of slots per pole per phase being NSPP (= 2) and the number of layers being 2 × NL (= 4), a configuration for reducing noise is disclosed.

[0003] Japanese Patent Application Laid-Open No. 2015-223076

[0004] In view of the configuration described in Patent Document 1, an object of the present invention is to provide a rotating electrical machine that achieves both suppression of reduction of effective magnetic flux and reduction of the 6th order component of torque ripple electrical angle.

[0005] The rotating electric machine comprises a stator core having at least two or more slots, slot conductors inserted through the slots of the stator core and constituting one of a plurality of layers in the slots, and connecting conductors that form coil ends by connecting the same ends of slot conductors inserted through different slots, and a multi-phase stator winding having a plurality of wave-wound circumferential windings, and a rotor that is rotatably supported with respect to the stator core via an air gap and has two or more poles, wherein the stator winding has a plurality of groups of slot conductors composed of a plurality of slot conductors of the same phase, and the slots in the stator core If the number of formations is Ns, the number of poles is Np, the number of pole slots that the connecting conductor spans at one coil end is N1, and the number of pole slots that the connecting conductor spans at the other coil end is N2, then N1 = Ns / Np + 2 and N2 = Ns / Np - 2. The plurality of slot conductors in the group of slot conductors are inserted so as to be adjacent to each other between the slots and between the layers in a predetermined number of formations of N slots in which the same phase is continuously arranged in the circumferential direction of the stator core, and the predetermined number N is N = NSPP + NL + 1 when the number of pole slots per phase is NSPP and the number of layers formed in one slot is 2 × NL.

[0006] We can provide a rotating electric machine that achieves both suppression of the reduction in effective magnetic flux and reduction of the sixth-order component of the torque ripple electrical angle.

[0007] An explanatory diagram of the configuration of a rotating electric machine according to one embodiment of the present invention. A diagram of the configuration of a slot conductor inserted into a slot of a stator core according to one embodiment of the present invention. A diagram of the configuration of a connecting conductor that spans the slots of a stator core according to one embodiment of the present invention. A diagram of the configuration of a slot conductor inserted into a slot of a stator core according to one embodiment of the present invention and a modified example. A diagram of the configuration of a slot conductor inserted into a slot of a stator core according to a modified example of the present invention.

[0008] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are illustrative for illustrating the present invention, and have been omitted and simplified as appropriate for clarity of explanation. The present invention can also be carried out in various other forms. Unless otherwise specified, each component may be singular or plural.

[0009] The positions, sizes, shapes, and ranges of the components shown in the drawings may not represent their actual positions, sizes, shapes, and ranges in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the positions, sizes, shapes, and ranges disclosed in the drawings.

[0010] (An Embodiment and Overall Configuration) (Figure 1) As shown in Figure 1(a), the stator 1 of a rotating electric machine is composed of a stator core 1a. A plurality of stator windings 2 are wound around the stator core 1a. The stator windings 2 are composed of a plurality of wave-wound circumferential windings. As shown in Figure 1(b), the stator core 1a has slots 3. The stator windings 2 include slot conductors 2b that are inserted into the slots 3 of the stator core 1a and constitute one of a plurality of layers L in the slot 3, and connecting conductors 2c that constitute a coil end 2a by connecting the same-side ends of slot conductors 2b inserted into different slots 3 as shown in Figure 3. Furthermore, because the stator windings 2 are wound around the stator core 1a, the stator 1 has multiple phases. Although not shown, a rotor is provided radially inside the stator core 1a, rotatably supported with an air gap relative to the stator core 1a, and having two or more poles.

[0011] As shown in Figure 1(b), in the stator core 1a, the slot 3 is composed of multiple layers L, and slot conductors 2b are inserted radially through each layer L. Insulating paper 4 is provided between the slot 3 and the slot conductors 2b, thereby insulating the slot 3 (stator core 1a) and the slot conductors 2b from each other. Each slot 3 has six layers.

[0012] A rotating electric machine having a stator 1 and a rotor is driven by input of three-phase alternating current (U-phase, V-phase, and W-phase) converted from direct current by a power conversion device (not shown). Specifically, the three-phase alternating current flows through the stator winding 2, generating a rotating magnetic field in the stator 1. The rotating magnetic field generated in the stator 1 acts on permanent magnets embedded in the rotor (not shown), generating torque in the rotating electric machine. For example, in the case of a rotating electric machine mounted on a vehicle, the rotational torque generated from the rotating electric machine is transmitted to the vehicle's wheels via a transmission, differential gear, etc.

[0013] (Figure 2) Figure 2 shows an example of the configuration of slot conductors 2b inserted into slots 3 formed in the stator core 1a of the stator 1 (Figure 1). Note that in the stator core 1a shown in the figure, the upper side of the drawing is the radially outer side (outer circumference), and the lower side of the drawing is the radially inner side (inner circumference). The stator 1 used in the embodiment of the present invention has 6 poles and 72 slots (4 slots per pole per phase).

[0014] The stator core 1a has at least two or more slots 3 formed in the circumferential direction. The slot conductors 2b each have multiple groups of slot conductors, each consisting of multiple slot conductors 2b of the same phase in the U-phase, V-phase, and W-phase. Of the slot conductor groups of the U-phase, V-phase, and W-phase formed in the slots 3 of the stator core 1a, the slot conductor group of the U-phase slot conductors 2b is shown as a slot range 11 in the diagram. The other slot conductor groups of the U-phase and the V-phase and W-phase are not described.

[0015] Each slot 3 has six slot conductors 2b inserted in a radially aligned manner. For example, the slot range 11 is an area of ​​eight slots in the circumferential direction, as shown in the figure. In other words, in the slots 3 arranged in the circumferential direction of the stator core 1a, if N is the number of predetermined slot formations where multiple slot conductors 2b in the group of slot conductors are arranged in a continuous line of the same phase in the circumferential direction of the stator core 1a, then N = 8.

[0016] The slot conductors 2b are shown as rectangles, but each phase's slot conductor 2b is shown with either a + or - symbol next to it. This represents the direction of the current in each phase. For example, current flows in opposite directions between the U-phase slot conductor 2b and the V-phase slot conductor 2b inserted into the same slot 3, and between the U-phase slot conductor 2b and the W-phase slot conductor 2b inserted into the same slot 3.

[0017] (Figures 3 and 4) In an embodiment of the present invention, as shown in Figure 3, in the stator winding 2 wound around the stator core 1a, the connecting conductor 2c spans a 14-slot pitch at one coil end and a 10-slot pitch at the other coil end. Thus, the coil ends on both sides wound around the stator core 1a are composed of winding patterns that span different slot pitches. This configuration is applied when a slot conductor 2b is inserted through four or more layers in a single slot 3.

[0018] The regularity of the arrangement of the U-phase stator winding 2 in the slot range 11 described in Figure 2 will now be explained. Let Ns be the number of slots formed in the stator core 1a, Np be the number of poles in the rotating electric machine, N1 be the number of pole slots that the connecting conductor 2c crosses at one coil end of the stator core 1a, and N2 be the number of pole slots that the connecting conductor 2c crosses at the other coil end of the stator core 1a. In this case, the relationships N1 = Ns / Np + 2 and N2 = Ns / Np - 2 hold true.

[0019] Furthermore, in the N slots 3 (slot range 11 in Figure 2) arranged continuously in the circumferential direction of the stator core 1a, multiple slot conductors 2b of the same phase are inserted so that at least a portion of them are adjacent to each other between slots and between layers. The predetermined number of slots N is given by N = NSPP + NL + 1, where NSPP is the number of slots per pole per phase and NL is the number of layers formed in each slot 3. This configuration makes it possible to reduce torque ripple while suppressing the reduction of effective magnetic flux.

[0020] Based on the aforementioned relational equations, the specific insertion positions of the slot conductors 2b in slot 3 will now be explained. The configurations of the slot conductors 2b shown in Figures 4(a) and 4(b) represent the configurations of four slots, which is half of the eight slots, of the configurations of the U-phase slot conductors 2b in the slot range 11 (eight slots) shown in Figure 2. The insertion positions of the slot conductors 2b in the remaining four slots, which are not shown, are the symmetrical inversions of the insertion positions of the slot conductors 2b shown in Figures 4(a) and 4(b).

[0021] Block 12 is composed of s adjacent slots 3 in the circumferential direction. Block 12 has half the number of slots of the slot range 11, which represents the area where groups of slot conductors of the same phase are lined up. In block 12, the first slot from the left in the diagram is n=1, the second slot is n=2, and so on.

[0022] Here, we will explain the regularity of the insertion positions of the slot conductors 2b in block 12. Let slot conductor C1 be a slot conductor 2b that constitutes one of the multiple phases, and slot conductor C2 be a slot conductor 2b that constitutes a phase different from the phase that slot conductor C1 constitutes. In Figure 4, slot conductor C1 is a U-phase slot conductor 2b, and slot conductor C2 is a V-phase slot conductor 2b. Also, current flows in opposite directions between slot conductor C1 and slot conductor C2.

[0023] In block 12, if the nth slot from the left in the drawing is designated as slot Sn, then in slot n=1, slot conductor C1 is inserted through the kth layer from the inner circumference side, in slot n=2, slot conductor C1 is inserted through the kth and k+2 layers from the inner circumference side, and in slots n=1 and n=2, slot conductor C2 is inserted through the other layers that slot conductor C1 is not inserted through.

[0024] On the other hand, in slots n=s, slot conductor C2 is inserted into the k-th layer from the outer edge, in slots n=s-1, slot conductor C2 is inserted into the k-th and k+2 layers from the outer edge, and in slots n=s and n=s-1, slot conductor C1 is inserted into the other layers that slot conductor C2 is not inserted into.

[0025] Furthermore, in the configurations common to Figures 4(a) and 4(b), in a rotating electric machine with NSPP = 4 slots per pole per phase, in order to reduce the sixth-order component of torque ripple, in slots Sn where n = 1, either slot conductor C1 or slot conductor C2 is inserted through one of the multiple layers L, and the other is inserted through the other layers L.

[0026] Specifically, the configuration of the slot conductors 2b in Figures 4(a) and 4(b) will be described. In the embodiment of Figure 4(a), in the slot with n=1, the U-phase slot conductor 2b is provided in the first layer from the inner circumference. In the slot with n=2, the U-phase slot conductor 2b is provided in the first and third layers from the inner circumference. In the slot with n=4, the V-phase slot conductor 2b is provided in the first layer from the outer circumference. In the slot with n=3, the V-phase slot conductor 2b is provided in the first and third layers from the outer circumference.

[0027] Furthermore, in the embodiment shown in Figure 4(b), in the slot with n=1, the U-phase slot conductor 2b is provided in the second layer from the inner circumference. In the slot with n=2, the U-phase slot conductor 2b is provided in the second and fourth layers from the inner circumference. In the slot with n=4, the V-phase slot conductor 2b is provided in the second layer from the outer circumference. In the slot with n=3, the V-phase slot conductor 2b is provided in the second and fourth layers from the outer circumference.

[0028] Furthermore, in slot Sn of block 12, the stator winding 2 constituting one of the multiple phases is inserted into the i-th layer from the inner circumference in slot n=1, and also into the i-th layer from the inner circumference in slot Sn n=2. If i < j, the stator winding 2 constituting one of the multiple phases is inserted into the j-th layer from the inner circumference in slot n=s, and also into the j-th layer from the inner circumference in slot n=s-1.

[0029] With this configuration, as shown in Figure 4(a), the reduction in effective magnetic flux is suppressed while the sixth-order component of torque ripple is suppressed, thereby reducing torque ripple. Furthermore, as shown in Figure 4(b), the insertion positions of the slot conductors 2b in the same-phase slot range 11 exhibit high left-right symmetry in the circumferential direction, thus suppressing characteristic differences regardless of the direction of rotation of the rotor.

[0030] This invention compares the present invention with a conventional configuration. In conventional coil end configurations, the slot-crossing pattern of the connecting conductor increases the coefficients of the fifth and seventh orders, resulting in a trade-off between the sixth-order torque ripple component and the main magnetic flux. This leads to a large sixth-order torque ripple component (sixth-order magnetomotive force component), making it difficult to reduce the sixth-order torque ripple component and posing a challenge to noise reduction (NV). The sixth-order electrical angle component is primarily determined by the main magnetic flux and winding coefficient of the magnetic circuit. However, adjusting only the main magnetic flux can improve NV but reduces output, requiring a balance between NV improvement and high output. However, the configuration described in the embodiment of the present invention allows for a wider slot-crossing width of the connecting conductor 2c compared to conventional designs. This suppresses the reduction in the effective magnetic flux while also reducing the torque of the sixth-order component, thus contributing to improved quietness (NV improvement). Furthermore, it can meet the demands for miniaturization and high output of rotating electric machines, as well as the demand for low torque ripple. Furthermore, the number of identical phase slots n that are continuous in the circumferential direction of the stator core 1a is n ≥ 2, which makes it possible to realize a configuration of NSPP = 2 or more, which was not previously considered, in the embodiment of the present invention.

[0031] (Figure 5) Figure 5 shows an example of applying the configuration of the slot conductor 2b shown in Figure 4(b) to each slot 3 of the stator core 1a. The black circles "●" shown represent the current flowing from the lead wire to the neutral point in the stator 1 (current flowing from the back to the front of the drawing), and the cross marks "×" represent the current flowing in the opposite direction to "●" (current flowing from the front to the back of the drawing). The slots shown represent two poles (360 degrees of electrical angle), with Nspp = 4, 6 layers per slot, and 2 parallel circuits.

[0032] The stator windings 2 wound around the stator core 1a employ, for example, a double star connection, with a first star connection consisting of a U1 phase winding group, a V1 phase winding group, and a W1 phase winding group, and a second star connection consisting of a U2 phase winding group, a V2 phase winding group, and a W2 phase winding group connected in parallel. The U1, V1, W1 phase winding group and the U2, V2, W2 phase winding group each consist of multiple loop windings. U1, U2, V1, V2, W1, and W2 shown in the diagram on the slot conductors 2b of each phase indicate the positions through which each of the aforementioned winding groups is inserted in each layer.

[0033] As mentioned above, when groups of stator windings of the same phase that constitute the stator winding 2 are connected in parallel, groups of stator windings of the same phase are arranged in the same slot 3 so that there is no phase difference in the same phase. As a result, there is no phase difference between the voltages induced in each group of stator windings, and therefore, even when connected in parallel, imbalances such as the flow of circulating current can be suppressed. This can be applied to both the configurations in Figure 4(a) and Figure 4(b).

[0034] It should be noted that the present invention is not limited to the embodiments described above, and various modifications and combinations of other configurations can be made without departing from the spirit of the invention. Furthermore, the present invention is not limited to having all the configurations described in the embodiments described above, and may also include configurations in which some of those configurations are omitted.

[0035] 1 Stator 1a Stator core 2 Stator winding 2a Coil end 2b Slot conductor 2c Connecting conductor 3 Slot 4 Insulating paper 11 Same phase slot range (U phase) 12 Block L layer

Claims

1. A stator winding comprising a stator core having at least two or more slots formed therein, a multi-phase stator winding having multiple wave-wound circumferential windings, comprising: a stator core having at least two or more slots formed therein; slot conductors inserted through the slots of the stator core and constituting one of a plurality of layers in the slots; and connecting conductors that form a coil end by connecting the same ends of the slot conductors inserted through different slots; and a rotor rotatably supported with respect to the stator core via an air gap, having two or more poles, wherein the stator winding has a plurality of groups of slot conductors composed of a plurality of slot conductors of the same phase, and when the number of slots formed in the stator core is Ns, the number of poles is Np, the number of pole slots that the connecting conductors cross at one coil end is N1, and the number of pole slots that the connecting conductors cross at the other coil end is N2, then N1 = Ns / Np + 2 and N2 = Ns / Np - 2. In the group of slot conductors, the plurality of slot conductors are inserted adjacent to each other in a predetermined number of N slots arranged in a continuous line of identical phases in the circumferential direction of the stator core, at least a portion of which are inserted between the slots and between the layers, wherein the predetermined number N is N = NSPP + NL + 1, where NSPP is the number of slots per pole per phase and 2 × NL is the number of layers formed in one slot.

2. The stator windings are configured by connecting groups of stator windings of the same phase in parallel, and the groups of stator windings of the same phase are arranged in the same slots, as described in claim 1.

3. A stator winding comprising a stator core having a plurality of slots, slot conductors inserted through the slots of the stator core and constituting one of a plurality of layers in the slots, and connecting conductors that form a coil end by connecting the same ends of the slot conductors inserted through different slots, having a plurality of wave-wound circumferential windings, and a rotor rotatably supported with respect to the stator core via an air gap, wherein the stator winding has a plurality of groups of slot conductors composed of a plurality of slot conductors of the same phase, the plurality of slots includes a block consisting of s slots adjacent in the circumferential direction, and current flows in opposite directions between a slot conductor C1 constituting one of the plurality of phases and a slot conductor C2 constituting a phase different from the phase constituting the slot conductor C1 of the plurality of phases. In the block, if the nth slot is designated as slot Sn, the slot conductor C1 in slot Sn is inserted through the kth layer from the inner circumference in the slot n=1, and through the kth and k+2th layers from the inner circumference in the slot n=2, and in the slots n=1 and n=2, the slot conductor C2 is inserted through the other layers through which the slot conductor C1 is not inserted.

4. The stator windings are configured by connecting groups of stator windings of the same phase in parallel, and the groups of stator windings of the same phase are arranged in the same slots, as described in claim 3.

5. The rotating electric machine according to claim 3, wherein the slot conductor C2 is inserted into the k-th layer from the outer periphery in the slot n=s, and into the k-th and k+2 layers from the outer periphery in the slot n=s-1, and the slot conductor C1 is inserted into the other layers in the slots n=s and s-1 through which the slot conductor C2 is not inserted.

6. The rotating electric machine according to claim 3, wherein n is the number of continuous slots of the same phase in the circumferential direction of the stator core, and n ≥ 2.

7. The rotating electric machine according to claim 6, wherein in the slot Sn, in the slot where n=1, the slot conductor C1 or the slot conductor C2 is inserted through one of the layers, and the other is inserted through the other layers.

8. The rotating electric machine according to claim 7, wherein in the slot Sn, the stator winding constituting one of the multiple phases is inserted into the i-th layer from the inner circumference side in the slot n=1, and into the i-th layer from the inner circumference side in the slot n=2, and if i < j, it is inserted into the j-th layer from the inner circumference side in the slot n=s, and into the j-th layer from the inner circumference side in the slot n=s-1.

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