Stator of a rotating electric machine

Abstract

The present invention provides a stator for a rotating electric machine that shortens and simplifies the busbars used to bring the coils out of the stator core, and that can achieve better operation, especially during charging. [Solution] The stator 2 of the rotating electric machine (two-phase motor 1) comprises a stator core 4 having a plurality of slots 7, each extending radially and arranged circumferentially, and a coil 5 consisting of a plurality of parallel coils (β1 coil and β2 coil) per phase, wound circumferentially so as to pass through a plurality of turns in the plurality of slots 7. The slots 7 consist of a first slot 7A, in which only one parallel coil (β1 coil or β2 coil) is wound, and a second slot 7B, which is located at a predetermined circumferential position different from the first slot 7A, and in which a mixture of multiple parallel coils is wound.

Description

Technical Field

[0001] The present invention relates to a stator of a rotating electric machine used as an electric motor or a generator.

Background Art

[0002] In recent years, in order for more people to have access to affordable, reliable, sustainable, and advanced energy, research and development have been carried out on miniaturization, weight reduction, yield improvement, etc., which contribute to energy efficiency. For example, an electric vehicle (EV: Electric Vehicle) has an advantage that it does not emit carbon dioxide, nitrogen oxides, etc. during driving because only a motor is used as a power source, and it is expected as a next-generation vehicle. Therefore, technologies related to improving the energy efficiency of motors mounted in electric vehicles and the like have been developed. As such a technology, for example, a rotating electric machine disclosed in Patent Document 1 can be cited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the above-described rotating electric machine, the end portion of the armature winding wound around the armature core is inserted into the turn at the innermost diameter of the slot. Therefore, in the above-described rotating electric machine, in order to connect the end portion of the armature winding to the drive circuit, it is necessary to draw out the end portion from the turn at the innermost diameter of the slot to the outside of the armature core using a complicated and long bus bar.

[0005] However, because the aforementioned rotating electric machine has such a structure, the stress applied to the busbar due to vibration, etc., can be amplified by the lever principle and applied to the part where the end of the armature winding is welded to the busbar. In addition, because the aforementioned rotating electric machine requires a complex and long busbar, a large amount of material is needed to manufacture the busbar, which reduces the busbar yield and makes miniaturization difficult.

[0006] This invention was made to solve the above-mentioned problems, and aims to provide a stator for a rotating electric machine that shortens and simplifies the busbars used to bring the coils out of the stator core, and that can achieve better operation, especially during charging. Ultimately, this invention contributes to energy efficiency. [Means for solving the problem]

[0007] To achieve the above objective, the stator 2 of the rotating electric machine (two-phase motor 1) according to claim 1 comprises a stator core 4 having a plurality of slots 7, each extending radially and arranged circumferentially, and a coil 5 composed of a plurality of parallel coils (e.g., β1 coil and β2 coil) per phase, wound circumferentially so as to pass through a plurality of turns in the plurality of slots 7, wherein the slots 7 are composed of a first slot 7A in which only one of the plurality of parallel coils (e.g., β1 coil or β2 coil) is wound, and a second slot 7B located at a predetermined circumferential position different from the first slot 7A, in which a mixture of multiple parallel coils is wound.

[0008] With this configuration, for example, a single parallel coil can be wound in one direction from the outermost turn to the innermost turn of the slot, then reversed via a busbar and wound in the opposite direction back to the outermost turn. In this way, the busbar only needs to be provided on the inner side of the slot, eliminating the need for a complex and long busbar to guide the coil from the inner side of the slot to the outside of the stator core, unlike conventional designs. This reduces the amount of material required to manufacture the busbar, improves the yield of the busbar, and allows for miniaturization.

[0009] Furthermore, with the above configuration, when reverse-phase current is applied, where the direction of the current in one parallel coil and the direction of the current in another parallel coil in one phase are reversed, the magnetic flux generated in one parallel coil and the magnetic flux generated in the other parallel coils can be prevented from interfering with each other, thereby improving the inductance.

[0010] The invention according to claim 2 is characterized in that, in the stator of the rotating electric machine described in claim 1, the first slot 7A and the second slot 7B are arranged alternately in the circumferential direction for each pole.

[0011] This configuration makes it possible to keep the pitch of the parallel coils inserted in the first slot 7A and the second slot 7B, as well as the pitch of the coils joining the ends of the parallel coils, constant, thereby simplifying the overall structure.

[0012] Furthermore, when two parallel coils are energized in opposite phases, magnetic flux is generated through the first slot of one parallel coil and the first slot of the other parallel coil. This reduces the number of stator poles, making it possible to create a mismatch with the number of rotor poles. Due to this mismatch in the number of poles, even if magnetic flux is generated by the alternating current supplied during charging, no torque is generated in the rotor, thus making it possible to reduce the torque during charging to zero.

[0013] The invention according to claim 3 is a stator for a rotating electric machine as described in claim 1, wherein the rotating electric machine has a two-phase configuration consisting of an α phase and a β phase, and is configured as a generator for charging a battery from an external power source using an inverter, the slot for the α phase consists only of a second slot 2B in which multiple parallel coils, namely α1 coils and α2 coils, the slot for the β phase consists of a first slot 7A in which only β1 coils or β2 coils exist, and a second slot 7B in which multiple parallel coils, namely β1 coils and β2 coils, and the first slot 7A and the second slot 7B for the β phase are arranged alternately in the circumferential direction for each pole.

[0014] In this configuration, in the α phase, where the slot is composed only of the second slot containing both α1 and α2 coils, reducing the inductance makes it easier to adjust the voltage during charging. On the other hand, in the β phase, which is composed of the first slot containing only either β1 or β2 coils and the second slot containing both β1 and β2 coils, the inductance can be improved, for example, by reversing the current flow, thereby reducing the power factor correction loss during charging. In this way, it becomes possible to differentiate between phases where you want to improve the inductance and phases where you want to reduce the inductance, thereby improving charging quality. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows an example of coil winding and arrangement in the stator of a two-phase motor according to an embodiment of the present invention, and an example of connection by busbars. [Figure 2] This diagram shows the operation of a two-phase motor. [Figure 3] This diagram shows the connection status of the coils to the inverter circuit. [Modes for carrying out the invention]

[0016] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In this embodiment, an example in which a two-phase motor is used as the rotating electric machine will be described. This two-phase motor 1 is mounted on an electric vehicle, for example, and is used as an electric motor to drive the wheels, and as a generator to generate electricity using the power of the wheels.

[0017] As shown in Figure 2, the two-phase motor 1 comprises a stator 2 and a rotor 3. The stator 2 comprises a stator core 4 and coils 5. The rotor 3 has eight permanent magnets arranged so that their magnetic poles alternate in opposite directions.

[0018] The stator core 4 is a cylindrical member, and numerous teeth 6 and slots 7 are arranged circumferentially inside it. The teeth 6 are the portion of the stator core 2 that extends radially toward the rotation axis A of the rotor 3, and the shape and dimensions of the cross-section perpendicular to the rotation axis A are constant regardless of their position in the axial direction. The slots 7 are spaces defined between each pair of adjacent teeth 6, 6, and therefore, like the teeth 6, they extend radially toward the rotation axis A, and the shape and dimensions of the cross-section perpendicular to the rotation axis A are constant regardless of their position in the axial direction.

[0019] Coil 5 is a wire wound around teeth 6. Specifically, coil 5 is wound around the entire stator core 4 by repeatedly connecting the ends of U-shaped flat wires, which are inserted into two slots 7, to the ends of other U-shaped flat wires. Coil 5 is an open winding that is connected to and incorporated into the inverter circuit 11 (see Figure 3) at both ends. With this configuration, when the two-phase motor 1 is used as an electric motor, coil 5 generates a magnetic force to rotate the rotor 3 around the rotation axis A in response to the energization by the inverter circuit 11, and when the two-phase motor 1 is used as a generator, it generates a current for power generation in response to the rotation of the rotor 3 and the change in the surrounding magnetic field.

[0020] Figure 1 shows an example of the winding method of coil 5 and the connection by bus bar 8. In this example, the two-phase motor 1 is composed of an α-phase and a β-phase, and each pole of each phase is composed of four slots 7. Therefore, the two-phase motor 1 includes coils α1 and α2 that are in parallel with each other and constitute the α-phase, and coils β1 and β2 that are in parallel with each other and constitute the β-phase. Note that Figure 1 mainly shows an example of the winding method of coil β1 and the connection by bus bar 8.

[0021] Each cell in the first row from the top of Figure 1 indicates the slot number assigned to each slot 7 of the stator core 4. As shown in the first row from the top of Figure 1, 64 slots 7 are formed in the stator core 7. Each cell from the second row to the ninth row from the top of Figure 1 indicates the position where one end of the U-shaped flat wire is inserted in each slot 7. The position numbers described in these cells indicate the order in which the flat wires constituting the coils of each phase (coil β1 in Figure 1) pass.

[0022] As shown in Figure 1, the cells with thick diagonal hatching indicate the positions where the flat wires constituting coil α1 are inserted, and the cells with thin diagonal hatching indicate the positions where the flat wires constituting coil α2 are inserted. Also, the cells with dot hatching indicate the positions where the flat wires constituting coil β1 are inserted, and the cells with vertical line hatching indicate the positions where the flat wires constituting coil β2 are inserted.

[0023] The second row to the ninth row from the top of Figure 1 respectively indicate the first turn to the eighth turn from the outer diameter side to the inner diameter side of the stator core 7. The term "turn" used here refers to 64 cells located at a certain distance from the outer diameter side of the stator core 7 in the radial direction of a circle located on a plane perpendicular to the rotation axis A with a point on the rotation axis A as the center.

[0024] Furthermore, the solid line in Figure 1 indicates that the curved portion of the U-shaped rectangular wire protrudes from the back to the front of the page in Figure 1. On the other hand, the dotted line in Figure 1 indicates that the end of the U-shaped rectangular wire protrudes from the back to the front of the page in Figure 1. The dashed line in Figure 1 indicates the busbar 8 that electrically connects the ends of the rectangular wires. The white circles in Figure 1 indicate the parts that are welded to electrically connect the ends of the rectangular wires, etc.

[0025] The winding method of coil β1 and the joining method using busbar 8 will be explained in detail below, with reference to Figure 1.

[0026] The starting end β1in of coil β1 is electrically connected to the end of the flat wire inserted in the first turn, which is the outermost turn of slot number 43, near the position of the first turn of slot number 39 in the light diagonal hatching, as shown in Figure 1.

[0027] Coil β1 comprises a flat wire with one end, positioned on the right in Figure 1, inserted at position number 1 of the first turn, and the other end, positioned on the left in Figure 1, inserted at position number 2 of the second turn. Coil β1 also comprises a flat wire with one end, positioned on the right in Figure 1, inserted at position number 3 of the first turn and electrically connected to the end of the flat wire inserted at position number 2, and the other end, positioned on the left in Figure 1, inserted at position number 4 of the second turn.

[0028] Coil β1 comprises a flat wire in which one end, positioned on the right in Figure 1, is inserted at position number 5 of the first turn and electrically connected to the end of the flat wire inserted at position number 4, and the other end, positioned on the left in Figure 1, is inserted at position number 6 of the second turn. Coil β1 comprises a flat wire in which one end, positioned on the right in Figure 1, is inserted at position number 7 of the first turn and electrically connected to the end of the flat wire inserted at position number 6, and the other end, positioned on the left in Figure 1, is inserted at position number 8 of the second turn.

[0029] As described above, coil β1 is wound in the first and second turns of slot 7 using the four flat wires mentioned above. Coil β1 is further wound in the same manner from the third turn to the innermost eighth turn of slot 7, in the direction from right to left in Figure 1, with the end of the final flat wire inserted at position number 64, which corresponds to the eighth turn of slot number 35. Thus, coil β1 is wound in the direction from right to left in Figure 1 from its starting position to position number 64 (hereinafter, this part will be referred to as the "forward winding section").

[0030] Furthermore, as will be described later, coil β1 is wound from position 65 at the 8th turn of slot number 40, which is five positions to the left of position number 64, to the end of the first turn, in the direction from left to right in Figure 1 (hereinafter, this part will be referred to as the "reverse winding section").

[0031] Busbar 8 electrically connects the end of the forward winding and the beginning of the reverse winding of coil β1 at the 8th turn of the innermost diameter of slot 7. Specifically, busbar 8 is electrically connected to the end of the flat wire inserted at position number 64 of the 8th turn of slot number 35 and to the end of the flat wire inserted at position number 65 of the 8th turn of slot number 40. Busbar 8 is shown by a dashed line in Figure 1.

[0032] The winding method for the reverse-wound section of the β1 coil will be described below. Coil β1 comprises a flat wire whose left end, positioned on the left side in Figure 1, is inserted at position number 65 of the 8th turn, and whose right end, positioned on the right side in Figure 1, is inserted at position number 66 of the 7th turn. Coil β1 also comprises a flat wire whose left end, positioned on the left side in Figure 1, is inserted at position number 67 of the 8th turn and electrically connected to the end of the flat wire inserted at position number 66, and whose right end, positioned on the right side in Figure 1, is inserted at position number 68 of the 7th turn.

[0033] Coil β1 comprises a flat wire whose left end, positioned on the left in Figure 1, is inserted at position number 69 of the 8th turn and electrically connected to the end of the flat wire inserted at position number 68, and whose right end, positioned on the right in Figure 1, is inserted at position number 70 of the 7th turn. Coil β1 comprises a flat wire whose left end, positioned on the left in Figure 1, is inserted at position number 71 of the 8th turn and electrically connected to the end of the flat wire inserted at position number 70, and whose right end, positioned on the right in Figure 1, is inserted at position number 72 of the 7th turn.

[0034] As described above, in the reverse-winding section, coil β1 is wound around the 8th and 7th turns of slot 7 using the four flat wires mentioned above. Coil β1 is further wound in a similar configuration from the 6th turn to the 1st turn of the stator core, in the direction from left to right in Figure 1, with the end of the final flat wire inserted at position number 128, which corresponds to the 1st turn of slot number 48.

[0035] The end of coil β1, β1out, is electrically connected to the end of the final rectangular wire inserted at position number 128, near the position of the first turn in slot number 44 of the light diagonal hatching, as shown in Figure 1.

[0036] Coils β2, α1, and α2 are wound in the same way as coil β1, and the specific winding method is as follows. As mentioned above, the position of slot 7 on which coil β2 is wound is indicated by the vertical hatching grid in Figure 1. The end of the flat wire at the start of winding coil β2 is inserted into a predetermined position at the first turn of the outermost diameter of slot 7. Starting from this position, coil β2 is wound in the same way as coil β1, from right to left in Figure 1, up to a predetermined position at the eighth turn of the innermost diameter of slot 7 (forward winding section). Furthermore, the winding direction of coil β2 is reversed by a busbar (not shown) similar to that of coil β1, and it is wound from left to right in Figure 1, up to a predetermined position at the first turn of the outermost diameter of slot 7 (reverse winding section).

[0037] The position of the slot 7 around which coil α1 is wound is indicated by the dark hatched grid in Figure 1. The end of the flat wire at the start of winding coil α1 is inserted into a predetermined position at the first turn of the outermost diameter of slot 7. Starting from this position, coil α1 is wound in the same manner as coil β1, from right to left in Figure 1, up to a predetermined position at the eighth turn of the innermost diameter of slot 7. Furthermore, the winding direction of coil α1 is reversed by a busbar (not shown), and it is wound from left to right in Figure 1, up to a predetermined position at the first turn of the outermost diameter of slot 7.

[0038] The position of the slot 7 around which coil α2 is wound is indicated by the lightly hatched grid in Figure 1. The end of the flat wire at the start of winding coil α2 is inserted into a predetermined position at the first turn of the outermost diameter of slot 7. Starting from this position, coil α2 is wound in the same manner as coil β1, from right to left in Figure 1, up to a predetermined position at the eighth turn of the innermost diameter of slot 7. Furthermore, the winding direction of coil α2 is reversed by a busbar (not shown), and it is wound from left to right in Figure 1, up to a predetermined position at the first turn of the outermost diameter of slot 7.

[0039] As a result of winding the four parallel coils (coil α1, coil α2, coil β1, and coil β2) around slot 7 of the stator 2 as described above, the arrangement (distribution) of the parallel coils in all slots 7 will be as shown in Figure 1. The arrangement of these parallel coils will be explained below.

[0040] First, as shown in Figure 1, one pole of one phase (α phase or β phase) of coil 5 is composed of four slots 7 (for example, slot numbers 28-31 or slot numbers 32-35), and the four slots 7 that constitute the pole of the α phase and the four slots 7 that constitute the pole of the β phase are arranged alternately in the circumferential direction throughout the stator 2. Furthermore, each slot 7 is classified into a slot 7 in which only one parallel coil (β1 coil or β2 coil) is wound (hereinafter referred to as "first slot 7A" as appropriate) and a slot 7 in which two parallel coils of the same phase (α1 coil and α2 coil or β1 coil and β2 coil) are arranged alternately from the first turn to the eighth turn (hereinafter referred to as "second slot 7B" as appropriate).

[0041] According to the above definition, as shown in the upper part of Figure 1, the arrangement of coils 5 within slot 7 in the range of slot numbers 28 to 59 is as follows: Slot number 28, 29...α1 and α2 coils 30, 31...α1 and α2 coils (staggered arrangement relative to slot numbers 28 and 29) 32, 33...β2 coil only 34, 35...β1 coil only 36, 37...α1 and α2 coils (same as slot numbers 28 and 29) 38, 39...α1 and α2 coils (same as slot numbers 30 and 31) 40, 41...β1 and β2 coils 42, 43...β1 and β2 coils (staggered relative to slot numbers 40 and 41) 44, 45...α1 and α2 coils (same as slot numbers 30 and 31) 46, 47...α1 and α2 coils (same as slot numbers 28 and 29) 48, 49...β1 coil only 50, 51...β2 coil only 52, 53...α1 and α2 coils (same as slot numbers 30 and 31) 54, 55...α1 and α2 coils (same as slot numbers 28 and 29) 56, 57...β1 and β2 coils (same as slot numbers 42 and 43) 58, 59...β1 and β2 coils (same as slot numbers 40 and 41)

[0042] As described above, the slot 7 for the α phase is composed only of the second slot 7B, which contains both α1 and α2 coils, while the slot 7 for the β phase is composed of the first slot 7A, which contains only either a β1 or β2 coil, and the second slot 7B, which contains both β1 and β2 coils.

[0043] Furthermore, as shown in the lower part of Figure 1, the arrangement of coils 5 within slot 7 in the range of slot numbers 60 to 27, which are shifted 180 degrees circumferentially from slot numbers 28 to 59, is the same as the arrangement in slot numbers 28 to 59 described above.

[0044] As described above, according to this embodiment, the α1 and α2 coils, which are parallel coils of the α phase, and the β1 and β2 coils, which are parallel coils of the β phase, are each wound in one direction from the 1st turn of the outermost diameter of the slot 7 to the 8th turn of the innermost diameter, then reversed via the busbar 8, and wound in the opposite direction from the 8th turn to the 1st turn of the outermost diameter. In this way, the busbar only needs to be provided on the inner diameter side of the slot 7, and unlike conventional designs, a complex and long busbar to guide the coil 5 from the inner diameter side of the slot 7 to the outside of the stator core 2 is unnecessary. This makes it possible to reduce the amount of material required to manufacture the busbar, and to improve the yield and miniaturize the busbar.

[0045] Furthermore, the slots 7 around which the β-phase coils 5 are wound consist of a first slot 7A (for example, slot numbers 34-37) around which only the β1 coil or β2 coil is wound, and a second slot 7B (for example, slot numbers 40-43) around which the β1 and β2 coils are wound alternately. With this configuration, when reverse-phase current is applied, in which the direction of the current in the β1 coil and the direction of the current in the β2 coil are reversed, the magnetic flux generated in the β1 coil and the magnetic flux generated in the β2 coil can be prevented from interfering with each other, as shown in Figure 2, thereby improving the inductance.

[0046] Furthermore, four first slots 7A and four second slots 7B for the β phase are arranged at equal intervals on both sides of the four slots 7 for the α phase. This configuration allows for a constant pitch for the flat wires inserted into the first slots 7A and second slots 7B, as well as the pitch of the coils joining the ends of the two flat wires, thereby simplifying the overall structure.

[0047] Furthermore, when reverse-phase current is applied to the β1 and β2 coils, as shown in Figure 2, two magnetic fluxes are generated passing through the first slot 7A of the β1 coil and two magnetic fluxes passing through the first slot 7A of the β2 coil, resulting in the stator 2 being equivalent to a 4-pole system. In contrast, the rotor 3 has 8 poles, so the number of poles is mismatched. Due to this mismatch in the number of poles, even if magnetic flux is generated by the AC voltage supplied during charging, no torque is generated in the rotor 3, making it possible to reduce the torque during charging to zero.

[0048] Furthermore, in the α phase, where slot 7 is composed solely of the second slot 7B, which contains both α1 and α2 coils, reducing the inductance makes it easier to adjust the voltage during charging. On the other hand, in the β phase, which is composed of the first slot 7A, which contains only either the β1 or β2 coil, and the second slot 7B, which contains both the β1 and β2 coils, the inductance can be improved, for example, by reversing the current flow, thereby reducing the power factor correction loss during charging. In this way, it becomes possible to differentiate between phases where you want to improve the inductance and phases where you want to reduce the inductance, thereby improving charging quality.

[0049] In the embodiments described above, the example given was that the rotating electric machine in the embodiment is a two-phase motor, but the invention is not limited to this, and for example, a three-phase motor may also be used. Furthermore, the present invention is not limited to the embodiments described above. That is, the present invention includes embodiments that have been modified, substituted, or redesigned in accordance with the spirit of the present invention, and these embodiments are not excluded. [Explanation of Symbols]

[0050] 1. Two-phase motor (rotating electric machine) 2 staters 3 rotors 4 Stator Core 5 coils 6 teeth 7 slots 11. Inverter Circuit (Inverter) A motor's rotation axis

Claims

1. A stator core having multiple slots, each extending radially and arranged circumferentially, Each phase comprises a coil consisting of multiple parallel coils, wound circumferentially so as to pass through multiple turns in the multiple slots, The stator of a rotating electric machine is characterized in that the slot is composed of a first slot on which only one of the plurality of parallel coils is wound, and a second slot located at a predetermined circumferential position different from the first slot, on which the plurality of parallel coils are wound together.

2. The stator of a rotating electric machine according to claim 1, characterized in that the first slot and the second slot are arranged alternately in the circumferential direction for each pole.

3. The aforementioned rotating electric machine has a two-phase configuration consisting of α-phase and β-phase, and is configured as a generator for charging a battery from an external power source using an inverter. The stator of a rotating electric machine according to claim 1, characterized in that the slot for the α phase is composed only of a second slot in which the α1 coil and α2 coil as a plurality of parallel coils are mixed, the slot for the β phase is composed of a first slot in which only a β1 coil or a β2 coil is present, and a second slot in which the β1 coil and β2 coil as a plurality of parallel coils are mixed, and the first slot and the second slot for the β phase are arranged alternately in the circumferential direction for each pole.

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