Wound field-type rotating electrical machine

Abstract

In this wound field-type rotating electrical machine, a rotor (60) includes: a rotor core (61) having a main pole part (62) which is provided for each magnetic pole arranged in the circumferential direction and which projects in the radial direction; and a field winding wound around the main pole part. The field winding has a series connection body of a first winding part (first coil module 111) and a second winding part (second coil module 112), and each winding part is wound around each main pole part, with the first winding part being on the side close to a stator in the radial direction, and the second winding part being on the side far from the stator in the radial direction. The first winding part constitutes a series resonance circuit by being connected in series to a capacitor, and the second winding part constitutes a parallel resonance circuit by being connected in parallel to the capacitor. The second winding part has a larger number of windings than the first winding part, and the conductive wire material used for the second winding part has a smaller conductor cross-sectional area than the conductive wire material used for the first winding part.

Description

Wound-field type rotating electric machine CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-118124, filed on July 20, 2023, the contents of which are incorporated herein by reference.

[0002] The disclosure in this specification relates to a wound field type rotating electric machine.

[0003] A known example of this type of wound-field rotating electric machine is the rotating electric machine described in Patent Document 1. In this rotating electric machine, a field winding is wound around the main pole portion (magnetic salient pole portion) of each circumferentially arranged magnetic pole of a rotor. Harmonic currents flowing through a winding (stator winding) of a stator arranged opposite the rotor induce a field current in the field winding. The field winding has a first winding portion and a second winding portion connected in series. The first winding portion is wound around the main pole portion, with the first winding portion closer to the stator and the second winding portion farther from the stator in the radial direction. The first winding portion and a capacitor form a series resonant circuit, and the second winding portion and a capacitor form a parallel resonant circuit. In this case, it is desirable to have a larger number of turns of wire in the second winding portion than in the first winding portion.

[0004] Japanese Patent Application Laid-Open No. 2020-54064

[0005] In a wound-field rotating electric machine having the above configuration, if the number of turns of the conductor in the second winding section is greater than the number of turns of the conductor in the first winding section, the current value (effective current value) in the second winding section will be smaller than the current value in the first winding section. In this case, if the conductors in the first and second winding sections have the same conductor cross-sectional area, the conductor cross-sectional area will be excessively large despite the relatively small current flowing in the second winding section. This raises concerns that the number of turns in the second winding section will be unnecessarily limited, resulting in limitations on the field current.

[0006] The present disclosure has been made in view of the above circumstances, and has an object to provide a wound-field rotating electric machine that can increase the field current flowing through the field winding.

[0007] The present disclosure relates to a wound-field rotating electric machine comprising: a stator having a stator winding; a rotor having a rotor core with main pole portions provided for each circumferentially arranged magnetic pole and protruding in the radial direction, and a field winding wound around the main pole portions, wherein a high-frequency current flows through the stator winding to induce a field current in the field winding, the field winding having a series connection of a first winding portion and a second winding portion, and each winding portion is wound around each main pole portion with the first winding portion on the radially closer side to the stator and the second winding portion on the radially farther side from the stator, the first winding portion being connected in series to a capacitor to form a series resonant circuit, and the second winding portion being connected in parallel to the capacitor to form a parallel resonant circuit, the second winding portion having a larger number of turns than the first winding portion, and the conductor cross-sectional area of ​​the conductor used for the second winding portion being smaller than that of the conductor used for the first winding portion.

[0008] A rotor for a wound-field rotating electric machine may have a field winding formed by a series connection of a first winding portion and a second winding portion, with each winding portion and a capacitor forming a series resonant circuit and a parallel resonant circuit, and the number of turns of the second winding portion radially farther from the stator may be greater than the number of turns of the first winding portion radially closer to the stator. In this case, by increasing the number of turns of the second winding portion relative to the first winding portion, the inductance of the second winding portion increases, allowing for an increase in field current. Here, with a configuration in which the number of turns of the second winding portion is greater than that of the first winding portion, the current value (effective current value) of the second winding portion is smaller than that of the first winding portion. In other words, the current that can be passed through the second winding portion only needs to be smaller than that of the first winding portion.

[0009] In consideration of this, the cross-sectional area of ​​the conductor of the wire material used in the second winding section is made smaller than that of the conductor of the wire material used in the first winding section. This allows the number of turns in the second winding section to be increased compared to when wire material with the same conductor cross-sectional area is used in the first and second winding sections. As a result, the field current flowing through the field winding can be increased.

[0010] The above and other objects, features, and advantages of the present disclosure will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which Fig. 1 is an overall configuration diagram of a control system for a rotating electric machine, Fig. 2 is a diagram showing an inverter and its peripheral configuration, Fig. 3 is a cross-sectional view of a rotor and a stator, Fig. 4 is a diagram showing an electric circuit provided in the rotor, Fig. 5 is a perspective view showing the overall configuration of the rotor, Fig. 6 is an exploded perspective view of the rotor, Fig. 7 is a vertical cross-sectional view of the rotor, Fig. 8 is a perspective view showing an exploded winding unit in the rotor main section, Fig. 9 is a cross-sectional view of the rotor main section, and Fig. 10 is a first FIG. 11 is a cross-sectional view showing the state in which the winding section is wound around each main pole section of the rotor core; FIG. 12 is an oblique view showing the configuration regarding the connection of the coil body in each winding section; FIG. 13 is an electrical circuit diagram of the rotor; FIG. 14 is a cross-sectional view of the wire material; FIG. 15 is a longitudinal cross-sectional view showing the state in which the wire ends of the coil body are joined together in the component holder; and FIG. 16 is a cross-sectional view showing the wire material of the first winding section and the second winding section.

[0011] DETAILED DESCRIPTION OF THE INVENTION A rotating electric machine according to an embodiment of the present disclosure will now be described with reference to the drawings. Rotating electric machines are used as a power source for driving electric vehicles such as electric vehicles and hybrid vehicles.

[0012] First, a control system including a rotating electric machine will be described with reference to Fig. 1. The control system includes a DC power supply 10, an inverter 20, a control device 30, and a rotating electric machine 40. The rotating electric machine 40 is a wound-field type synchronous machine. For example, the rotating electric machine 40, the inverter 20, and the control device 30 may be configured as an electromechanical integrated drive device, or the rotating electric machine 40, the inverter 20, and the control device 30 may each be configured as a separate component.

[0013] The rotating electric machine 40 includes a housing 41 and a stator 50 and a rotor 60 housed within the housing 41. The rotating electric machine 40 of this embodiment is an inner rotor type rotating electric machine in which the rotor 60 is disposed radially inside the stator 50. The stator 50 includes a stator core 51 and a stator winding 52. The stator winding 52 is formed of, for example, copper wire and includes U-, V-, and W-phase windings 52U, 52V, and 52W that are disposed with a 120° electrical angle offset from one another. The rotor 60 includes a rotor core 61 and a field winding 70. A rotating shaft 32 is assembled in the center hole of the rotor core 61. The rotating shaft 32 is rotatably supported by the housing 41 via bearings 42 and 43.

[0014] As shown in FIG. 2 , the inverter 20 includes a series connection of upper-arm switches SUp, SVp, and SWp for U, V, and W phases and lower-arm switches SUn, SVn, and SWn for U, V, and W phases. First ends of U-, V-, and W-phase windings 52U, 52V, and 52W are connected to the connection points between the upper-arm switches SUp, SVp, and SWp and the lower-arm switches SUn, SVn, and SWn for each phase. Second ends of the U-, V-, and W-phase windings 52U, 52V, and 52W are connected to the neutral point. That is, in this embodiment, the stator winding 52 is star-connected. However, the stator winding 52 may also be delta-connected. In this embodiment, each of the switches SUp to SWn is an IGBT. A freewheel diode is connected in antiparallel to each of the switches SUp to SWn.

[0015] The collectors of the upper arm switches SUp, SVp, SWp of each phase are connected to the positive terminal of a DC power supply 10. The emitters of the lower arm switches SUn, SVn, SWn of each phase are connected to the negative terminal of the DC power supply 10. A smoothing capacitor 11 is connected in parallel to the DC power supply 10.

[0016] Next, the stator 50 and the rotor 60 will be described with reference to FIG.

[0017] The stator 50 and the rotor 60 are both arranged coaxially with the rotating shaft 32. In the following description, the direction in which the rotating shaft 32 extends is referred to as the axial direction, the direction extending radially from the center of the rotating shaft 32 is referred to as the radial direction, and the direction extending circumferentially around the rotating shaft 32 is referred to as the circumferential direction.

[0018] The stator core 51 is made of laminated steel plates made of a soft magnetic material and has an annular back yoke 51a and multiple teeth 51b protruding radially inward from the back yoke 51a. Multiple slots 54 are formed between adjacent teeth 51b in the circumferential direction. The stator winding 52 is formed by accommodating the phase windings of each phase in a predetermined order in each of these slots 54. For example, the stator 50 may employ a segment coil structure using multiple conductor segments. However, the structure of the stator winding 52 is arbitrary.

[0019] The rotor core 61 is made of a soft magnetic material, for example, laminated steel plates. The rotor core 61 has a cylindrical portion 61a and a plurality of main pole portions 62 that protrude radially outward from the cylindrical portion 61a. A field winding 70 is wound around the main pole portions 62 by concentrated winding. In this embodiment, eight main pole portions 62 are provided at equal intervals in the circumferential direction.

[0020] The field winding 70 includes a first winding portion 71a and a second winding portion 71b. The first winding portion 71a is wound radially outward around each main pole portion 62, and the second winding portion 71b is wound radially inward relative to the first winding portion 71a. In terms of the relationship with the stator 50, the first winding portion 71a is wound radially closer to the stator 50, and the second winding portion 71b is wound radially farther from the stator 50. In each main pole portion 62, the winding directions of the first winding portion 71a and the second winding portion 71b are the same. Furthermore, of circumferentially adjacent main pole portions 62, the winding directions of the winding portions 71a, 71b wound around one are opposite to those of the winding portions 71a, 71b wound around the other. Therefore, the magnetization directions of circumferentially adjacent main pole portions 62 are opposite to each other. In the rotor 60, each main pole portion 62 of the rotor core 61 and a field winding 70 wound around each main pole portion 62 form a plurality of magnetic poles (field poles) arranged in the circumferential direction.

[0021] 4 shows an electrical circuit on the rotor 60 side, including the winding portions 71a, 71b wound around the main pole portion 62. The first winding portion 71a and the second winding portion 71b are connected in series, and a capacitor portion CC, consisting of a plurality of first capacitors 91, is connected in parallel to the second winding portion 71b. The capacitor portion CC is configured as a parallel connection of the plurality of first capacitors 91. A second capacitor 92 is connected in parallel to the series connection of the first winding portion 71a and the second winding portion 71b. The second capacitor 92 is provided for noise suppression. The first capacitor 91 and the second capacitor 92 are, for example, multilayer ceramic capacitors and have the same configuration.

[0022] A diode 93 serving as a rectifying element is connected between both ends of the series-connected body made up of the winding portions 71 a and 71 b. That is, the first end of the first winding portion 71 a is connected to the cathode of the diode 93, and the first end of the second winding portion 71 b is connected to the second end of the first winding portion 71 a. The anode of the diode 93 is connected to the second end of the second winding portion 71 b.

[0023] In this embodiment, the first winding portion 71a, the first capacitor 91, and the diode 93 form a series resonant circuit, and the second winding portion 71b and the first capacitor 91 form a parallel resonant circuit. In this case, the first winding portion 71a is connected in series to the first capacitor 91, and the second winding portion 71b is connected in parallel to the first capacitor 91. If the first resonant frequency, which is the resonant frequency of the series resonant circuit, is f1 and the second resonant frequency, which is the resonant frequency of the parallel resonant circuit, is f2, these resonant frequencies f1 and f2 are expressed by the following equations (1) and (2). L1 is the inductance of the first winding portion 71a, L2 is the inductance of the second winding portion 71b, and C is the capacitance of the first capacitor 91. f1=1 / (2π√(L1×C)) ... (1) f2=1 / (2π√(L2×C)) ... (2) When a high-frequency excitation current flows through the stator winding 52, fluctuations occur in the magnetic circuit including the stator core 51 and the rotor core 61 due to the high-frequency components of the main magnetic flux. The fluctuations in the main magnetic flux generate induced voltages in each of the winding portions 71 a, 71 b, and currents are induced in each of the winding portions 71 a, 71 b. At this time, if induced voltages of the same polarity are generated in each of the winding portions 71 a, 71 b, the induced currents in each of the winding portions 71 a, 71 b do not cancel each other out, and the induced current increases. The diode 93 rectifies the current flowing through each of the winding portions 71 a, 71 b in one direction. As a result, a field current flows through the field winding 70 in the direction rectified by the diode 93, and the field winding 70 is excited.

[0024] 2, the control device 30 is mainly configured with a microcomputer (corresponding to a computer) that has a CPU. The control device 30 generates drive signals that turn on and off the switches SUp to SWn that make up the inverter 20. Specifically, the control device 30 converts DC power output from the DC power supply 10 into AC power and supplies the AC power to the U-, V-, and W-phase windings 52U, 52V, and 52W. The control device 30 generates drive signals that turn on and off the switches SUp to SWn and supplies the generated drive signals to the gates of the switches SUp to SWn.

[0025] The control device 30 turns on and off each of the switches SUp to SWn so that a composite current of the fundamental current and the high-frequency excitation current flows through each of the phase windings 52U, 52V, and 52W. The fundamental current is a current that mainly generates torque in the rotating electric machine 40. The high-frequency excitation current is a high-frequency current with a higher frequency than the fundamental current, and is a current that mainly excites the field winding 70. It is also possible to use a harmonic current as the high-frequency current. The phase currents flowing through the phase windings 52U, 52V, and 52W are shifted by 120 electrical degrees.

[0026] Next, a more detailed description will be given of the configuration of the rotor 60. Fig. 5 is a perspective view showing the overall configuration of the rotor 60, Fig. 6 is an exploded perspective view of the rotor 60, and Fig. 7 is a vertical cross-sectional view of the rotor 60.

[0027] The rotor 60 is broadly divided into a rotor main section 101, a circuit module 102 provided at one of the axial ends of the rotor main section 101, and coil end covers 103, 104 as annular members attached to one and the other axial ends of the rotor main section 101. As described in Fig. 3, the rotor main section 101 includes the rotor core 61 and the field winding 70, and the rotating shaft 32 is attached to the central hole of the rotor core 61. The field winding 70 is made up of a plurality of winding units 110 arranged in a circumferential direction.

[0028] The circuit module 102 is fixed to the rotating shaft 32 with the rotating shaft 32 inserted into the hollow portion. The circuit module 102 is provided at a position axially facing the coil end portion of the field winding 70. The circuit module 102 is an electric circuit section that includes the capacitors 91, 92 and diode 93 described in FIG. 4, as well as bus bars that electrically connect these elements.

[0029] Fig. 8 is an exploded perspective view of the winding unit 110 in the rotor main section 101, and Fig. 9 is a cross-sectional view showing the cross-sectional structure of a portion of the rotor main section 101. The rotor main section 101 has a plurality of winding units 110, one for each magnetic pole of the rotor 60. Each winding unit 110 is formed in an annular shape with the axial direction as the longitudinal direction, and is assembled to the rotor core 61 with the main pole section 62 of the rotor core 61 inserted into the hollow portion.

[0030] The winding unit 110 has a first coil module 111 that is located radially outward when attached to the main pole 62, and a second coil module 112 that is located radially inward. The first coil module 111 is a coil module that corresponds to the first winding portion 71a, and the second coil module 112 is a coil module that corresponds to the second winding portion 71b.

[0031] The first coil module 111 has an annular coil body 121 formed by winding a conductor material made of a rectangular wire multiple times in the circumferential and radial directions of the rotor 60, and a thin plate-like insulator 122 provided integrally with the coil body 121. The insulator 122 has a portion that extends circumferentially and covers the radially outer and inner sides of the coil body 121, and a portion that extends radially and covers the hollow portion of the coil body 121. In other words, the coil body 121 is insulated and coated with the insulator 122 at its radially inner and outer portions and at its inner peripheral portion facing the main pole 62.

[0032] The second coil module 112 has an annular coil body 123 formed by winding a conductor material made of a rectangular wire multiple times in the circumferential and radial directions of the rotor 60, and a thin plate-like insulator 124 provided integrally with the coil body 123. The insulator 124 has a portion that extends circumferentially and covers the radially outer and inner sides of the coil body 123, and a portion that extends radially and covers the hollow portion of the coil body 123. In other words, the coil body 123 is insulated and coated with the insulator 124 at its radially inner and outer portions and at its inner peripheral portion facing the main pole 62.

[0033] The coil bodies 121, 123 are configured as, for example, α-winding coils, and are air-core coils in which the conductor material is wound in multiple layers in the overlapping direction (rotor circumferential direction) and in two layers in the extending direction of the hollow portion (rotor radial direction). In this embodiment, the conductor material of the coil bodies 121, 123 is a flat conductor wire whose conductor cross section is rectangular with long and short sides. The coil bodies 121, 123 are wound in such a way that the long sides overlap in multiple layers as the conductor material turns around. The flat wire consists of a conductor made of aluminum or the like and an insulating layer covering the conductor.

[0034] In the first coil module 111, two conductor ends 125 are drawn out in the axial direction from one coil body 121. In the second coil module 112, a total of six conductor ends 126 are drawn out in the axial direction from three coil bodies 123 arranged radially.

[0035] As shown in FIG. 9 , the first coil module 111 has two radially wound layers of conductor wire, while the second coil module 112 has six radially wound layers. Regarding the coil bodies 121 and 123, the first coil module 111 has one radially wound coil body 121, while the second coil module 112 has three radially wound coil bodies 123. In this case, the number of turns of the second winding portion 71b in each main pole 62 is greater than the number of turns of the first winding portion 71a. The coil modules 111 and 112 differ in the number of circumferential turns (i.e., the number of rows of conductor wire in the circumferential direction), with the number of turns being greater on the radially outer side than on the radially inner side. This improves the space factor of the field winding 70.

[0036] Furthermore, in the rotor main section 101, holding plates 127 and 128 are provided between the main pole sections 62 of the rotor core 61 to hold the first coil module 111 and the second coil module 112 in an assembled state when these coil modules 111 and 112 are assembled to each main pole section 62. The holding plate 127 is attached to the radial outside of the first coil module 111, and the holding plate 128 is attached between the first coil module 111 and the second coil module 112.

[0037] 6, the rotor 60 has a coil end ring 81 attached to the axial end of the winding unit 110. As shown in FIG. 7, the coil end ring 81 is disposed radially between the coil end portion of the first coil module 111 and the coil end portion of the second coil module 112, and is sandwiched axially between the retaining plate 128 and the coil end cover 103.

[0038] In the present embodiment, the wound-field rotor 60 includes the field winding 70, and the winding portions 71a and 71b, which together form a series resonant circuit and a parallel resonant circuit. The number of turns of the radially inner second winding portion 71b is greater than the number of turns of the radially outer first winding portion 71a. In this configuration, the number of turns of the second winding portion 71b is greater than that of the first winding portion 71a, thereby increasing the inductance of the second winding portion 71b and enabling an increase in the field current. In this configuration, the number of turns of the second winding portion 71b is greater than that of the first winding portion 71a. Therefore, the current value (effective current value) of the second winding portion 71b is smaller than that of the first winding portion 71a. In other words, the current that can be passed through the second winding portion 71b only needs to be smaller than that of the first winding portion 71a.

[0039] In consideration of this point, in this embodiment, the conductor cross-sectional area of ​​the conductor wire used in the second winding portion 71b is made smaller than the conductor cross-sectional area of ​​the conductor wire used in the first winding portion 71a. Below, the characteristics of the winding structure of the field winding 70 will be described.

[0040] Fig. 10 is a cross-sectional view schematically illustrating the wires C1 and C2 of the first winding portion 71a and the second winding portion 71b, showing one coil body 121 of the first winding portion 71a and one coil body 123 of the second winding portion 71b wound around the main pole 62. The up-down direction in the figure is the radial direction, and the left-right direction in the figure is the circumferential direction.

[0041] As shown in FIG. 10 , the conductor material C1 of the coil body 121 (first winding portion 71a) and the conductor material C2 of the coil body 123 (second winding portion 71b) have different cross-sectional areas, i.e., conductor cross-sectional areas, with the conductor material C2 having a smaller conductor cross-sectional area than the conductor material C1. More specifically, if the lengths of the long and short sides of the conductor material C1 are D1 and D2, and the lengths of the long and short sides of the conductor material C2 are D3 and D4, these lengths satisfy the relationship D1 = D3 and D2 > D4. In other words, the conductor material C2 has the same long side length as the conductor material C1 but a smaller short side length. In this case, the number of turns in the second winding portion 71b can be increased compared to when conductor materials with the same conductor cross-sectional areas are used in the first winding portion 71a and the second winding portion 71b.

[0042] 9, in the rotor core 61, the space between circumferentially adjacent main pole portions 62 is a winding space for the conductor wire, and when viewed in the radial direction, the winding space is relatively narrower on the radially inner side. In this regard, because the conductor cross-sectional area of ​​the conductor wire C2 of the second winding portion 71b is smaller than the conductor cross-sectional area of ​​the conductor wire C1 of the first winding portion 71a, the number of turns of the conductor wire C2 can be ensured even in a relatively narrow winding space.

[0043] FIG. 11 is a schematic diagram showing the state in which the winding portions 71a, 71b are wound around the main pole portions 62 of the rotor core 61. In FIG. 11, the two radially outer conductor layers are designated as the first winding portion 71a, and the four radially inner conductor layers are designated as the second winding portion 71b. The first winding portion 71a is configured by assembling coil bodies 121 to the main pole portions 62 aligned in the circumferential direction and connecting the coil bodies 121 in series. Here, the coil bodies 121 constituting the first winding portion 71a are designated C11, C12, C13, ..., C18 in clockwise order, and the first winding portion 71a is configured by connecting adjacent coil bodies C11 to C18 in series with each other in the circumferential direction.

[0044] The second winding portion 71b is configured by assembling two coil bodies 123 to each of the main pole portions 62 arranged circumferentially, and connecting the coil bodies 123 in series. Here, the coil bodies 123 of the second winding portion 71b adjacent to the first winding portion 71a are sequentially designated C21, C22, C23, ..., C28, and the coil bodies 123 radially inward thereof are sequentially designated C31, C32, C33, ..., C38. The second winding portion 71b is configured by connecting one end of each series-connected coil body C21 to C28 to one end of each series-connected coil body C31 to C38. While FIG. 11 illustrates two coil bodies 123 assembled to each main pole portion 62 for ease of explanation, the same applies when three or more coil bodies are assembled.

[0045] Fig. 12 is a perspective view showing the configuration relating to the connection of the coil bodies 121, 123 in each winding portion 71a, 71b in the rotor 60. Fig. 12 shows a state in which the circuit module 102 is assembled to one axial side of the rotor main portion 101.

[0046] The circuit module 102 includes a component holder 130 that holds the capacitors 91, 92 and diode 93 described above. The component holder 130 is made of an electrically insulating material such as synthetic resin. The component holder 130 includes a circular main body 131 and a plurality of conductor fixing portions 132 that extend radially outward from the main body 131. Although not shown in FIG. 12 because they are covered by the resin mold portion 105, the capacitors 91, 92 and diode 93 are arranged in a circular ring shape surrounding the rotating shaft 32 on the main body 131.

[0047] The component holder 130 is provided with eight conductor fixing portions 132, the same number as the main pole portions 62. Each conductor fixing portion 132 is formed with a plurality of insertion holes 133 penetrating in the axial direction. The conductor wire ends 125, 126 extending from the coil bodies 121, 123 of each winding portion 71 a, 71 b are inserted into the insertion holes 133, and the inserted conductor wire ends 125, 126 are joined to each other by welding or the like.

[0048] Of the eight conductor fixing portions 132, three conductor fixing portions 132A, 132B, and 132C shown in FIG. 12 will be described in detail.

[0049] In the conductor fixing portion 132A, the coil bodies 121, 123 arranged in four radial rows are connected to each other. Specifically, in the conductor fixing portion 132A, at connection portion X1, the conductor end portions 125 of each circumferentially adjacent coil body 121 are inserted one by one into the insertion hole 133, and the conductor end portions 125 are connected to each other. Furthermore, at connection portions X2 to X4, the conductor end portions 126 of each circumferentially adjacent coil body 123 are inserted one by one into the insertion hole 133, and the conductor end portions 126 are connected to each other. At connection portion X5, bus bars 141, 142 for connection to the first capacitor 91 are connected.

[0050] At the connection portions X1 to X4, i.e., the portions where the conductor ends 125 or 126 of the coil bodies 121 and 123 are connected to each other, the coil bodies 121 and 123 are connected by welding or the like with the long sides of the rectangular conductor wires joined to each other. In this case, a larger joint surface can be secured compared to a configuration in which the short sides of the conductor wires are joined to each other. This allows for an appropriate connection in terms of both strength and conductivity.

[0051] In the conductor fixing portion 132A, the conductor wire ends 126 of the coil bodies 123 are connected to each other at three connection points X2 to X4. In other words, in the second winding portion 71b, the conductor wire ends 126 are connected to each other at the same number of locations as the number of coil bodies 123 arranged circumferentially. If the conductor cross-sectional area of ​​the conductor wire material C2 of the coil body 123 were configured to be smaller than that of the conductor wire material C1 of the coil body 121, and the radial width dimension of the conductor wire material C2 in the second winding portion 71b were made smaller than that of the conductor wire material C1, the number of coil bodies 123 arranged radially would increase, and the number of connection points connecting the coil bodies 123 to each other would increase. In this regard, in this embodiment, the circumferential width dimension of the conductor wire material C2 is made smaller than that of the conductor wire material C1 to reduce the cross-sectional area of ​​the conductor wire material C2, so the number of coil bodies 123 arranged radially does not increase. This prevents a decrease in workability due to an increase in the number of connection points between the coil bodies 123.

[0052] On the other hand, in the conductor fixing portion 132B, the coil bodies 121, 123 in each row are connected to each other (lane change connection) and to the capacitors 91, 92 and the diode 93 via bus bars. Specifically, in the conductor fixing portion 132B, at connection point Y1, the conductor end 125 of the coil body 121 of the first winding portion 71a, one end of the bus bar 143 for the second capacitor 92, and an end of the bus bar 144 for connecting the cathode of the diode 93 are connected. This connection at connection point Y1 corresponds to the connection at connection point A1 in the circuit diagram of FIG. 13 . Furthermore, at connection point Y2, the conductor end 125 of the coil body 121 of the first winding portion 71a, the conductor end 126 of the coil body 123 of the second winding portion 71b, and an end of the bus bar 142 for the first capacitor 91 are connected. The connection at the connection point Y2 corresponds to the connection at the connection point A2 in the circuit diagram of FIG.

[0053] At the connection portion Y2, the conductor ends 125, 126 of the coil bodies 121, 123 are connected with the conductor wires C1, C2 (see FIG. 10 ) having different conductor cross-sectional areas joined together. Specifically, the conductor wires C1, C2 of the coil bodies 121, 123 are connected by welding or the like with their long sides joined together. In this case, although the conductor wires C1, C2 of the coil bodies 121, 123 have different conductor cross-sectional areas, the conductor wire C2 of the coil body 123 has the same length dimension of its long side as the conductor wire C1 of the coil body 121, so that a sufficient joint surface can be secured between them.

[0054] At the connection points Y3 and Y4, the conductor ends 126 of the coil bodies 123 in different rows are connected to each other. At the connection point Y5, bus bars 143 and 145 for connection to the second capacitor 92 are connected.

[0055] Furthermore, in the conductor fixing portion 132C, at connection point Z1, conductor end portion 126 of coil body 123 of second winding portion 71b, an end of bus bar 146 common to each of capacitors 91 and 92, and an end of bus bar 147 for connecting the anode of diode 93 are connected. The connection at connection point Z1 corresponds to the connection at connection point A3 in the circuit diagram of FIG.

[0056] At least one of the conductor wires C1, C2 of the first winding portion 71a and the second winding portion 71b may be a bundled wire (divided wire) formed by bundling a plurality of wires.

[0057] Specifically, as shown in FIG. 14( a), the conductor C1 is composed of a plurality of wires 151 and an outer covering 152 that covers each of the wires 151 from the outside. Also, as shown in FIG. 14( b), the conductor C2 is composed of a plurality of wires 151 and an outer covering 152 that covers each of the wires 151 from the outside. The conductors C1 and C2 are both composed of the same wires 151, but have different cross-sections due to the difference in the number of wires 151. The wires 151 may be coated wires having a conductor and an insulating coating that covers the conductor. The conductors C1 and C2 may also be composed of different wires 151. For example, the cross-sectional area of ​​the wires 151 of the conductor C1 may be larger than the cross-sectional area of ​​the wires 151 of the conductor C2. The wires 151 are rectangular wires with a cross-section, but may also be round wires. The conductor wires C1 and C2 may be twisted wires in which a plurality of wires 151 are twisted together.

[0058] In the rotating electric machine 40, a high-frequency current corresponding to the excitation frequency flows through the field winding 70 of the rotor 60, and therefore each of the winding portions 71 a, 71 b is likely to be affected by the skin effect. In this regard, by making the conductor materials C1, C2 of each of the winding portions 71 a, 71 b into bundled wires in which a plurality of strands 151 are bundled together, i.e., segmented wires in which the conductor cross section is divided into a plurality of sections, the influence of the skin effect in each of the winding portions 71 a, 71 b can be reduced.

[0059] Furthermore, in the field winding 70, the first winding portion 71a on the radially outer side is closer to the stator 50, and the second winding portion 71b on the radially inner side is farther from the stator 50, and there is a concern that eddy current loss will occur in the first winding portion 71a due to linkage of leakage flux of high-frequency excitation magnetic flux from the stator 50. As a countermeasure, it is advisable to make the volume resistivity of the conductor material of the first winding portion 71a larger than the volume resistivity of the conductor material of the second winding portion 71b.

[0060] Specifically, for example, the conductor material of the first winding portion 71a (coil body 121) is aluminum, and the conductor material of the second winding portion 71b (coil body 123) is copper. It is also possible to use carbon nanotubes (CNTs) as the conductor material of the first winding portion 71a and copper as the conductor material of the second winding portion 71b. This reduces the influence of leakage magnetic flux in the first winding portion 71a, thereby enabling the reduction of eddy current loss. Furthermore, by using different wire materials for the winding portions 71a and 71b, and using a material with low electrical resistance for the second winding portion 71b, which is relatively less affected by leakage magnetic flux, the reduction in current in the second winding portion 71b is suppressed.

[0061] When the first winding portion 71a is made of aluminum wire and the second winding portion 71b is made of copper wire, the conductor material of the first winding portion 71a has a higher volume resistivity and a lower specific gravity than the conductor material of the second winding portion 71b. This reduces eddy current loss caused by leakage flux from the stator 50 in the first winding portion 71a on the radially outer side (stator 50 side), and also reduces centrifugal force during rotor rotation.

[0062] If the first winding portion 71a and the second winding portion 71b are made of different materials, there is a concern that moisture may adhere to the joints, causing galvanic corrosion. In view of this, it is preferable that the joints between the conductive wires in the first winding portion 71a and the second winding portion 71b be covered with an insulating material.

[0063] 15 is a longitudinal cross-sectional view showing the state in which the conductor end 125 of the coil body 121 and the conductor end 126 of the coil body 123 are joined in the component holder 130 of the circuit module 102. In FIG. 15 , the conductor ends 125, 126 of the coil bodies 121, 123 are inserted into insertion holes 133 in the conductor fixing portion 132 of the component holder 130 and joined at their tip ends by welding or the like. A resin coating 161 made of a resin material such as epoxy resin is formed so as to cover the joint portion of the conductor ends 125, 126. The resin coating 161 is preferably provided so as to cover the entire joint portion of the conductor ends 125, 126 and so as to have a portion thereof extend into the insertion hole 133 of the conductor fixing portion 132. Resin coating 161 prevents galvanic corrosion at the joint between first winding portion 71a and second winding portion 71b even if they are made of different materials.

[0064] In addition, the resin coating portion 161 may be provided not only at the joint between the conductor end portion 125 of the coil body 121 and the conductor end portion 126 of the coil body 123, but also at other joint portions, i.e., the joint between the conductor end portions 125 of the coil body 121 and the joint between the conductor end portions 126 of the coil body 123.

[0065] According to the present embodiment described above in detail, the following excellent effects can be obtained.

[0066] In the field winding 70, the conductor cross-sectional area of ​​the wire material C2 used in the second winding portion 71b is smaller than the conductor cross-sectional area of ​​the wire material C1 used in the first winding portion 71a. This allows the number of turns in the second winding portion 71b to be increased compared to when wire materials with the same conductor cross-sectional area are used in the first winding portion 71a and the second winding portion 71b. As a result, the field current flowing in the field winding 70 can be increased, and ultimately the torque of the rotating electric machine 40 can be improved.

[0067] In the rotating electric machine 40, a high-frequency current corresponding to the excitation frequency flows through the field winding 70 of the rotor 60, and therefore each of the winding portions 71 a, 71 b is likely to be affected by the skin effect. In this regard, by using bundled wire as the conductor material for each of the winding portions 71 a, 71 b, the influence of the skin effect in each of the winding portions 71 a, 71 b can be reduced.

[0068] The cross-sectional area of ​​the conductor of the wire C2 of the second winding portion 71b is smaller than that of the wire C1 of the first winding portion 71a, and the length of the long sides of the wire C2 of the second winding portion 71b is the same as that of the wire C1 of the first winding portion 71a, but the length of the short sides is smaller than that of the wire C1. This ensures a sufficient joint surface when the long sides of the winding portions 71a, 71b are joined together, allowing for appropriate welding and other processes.

[0069] Increasing the number of coil bodies 123 arranged radially in the second winding portion 71b increases the number of connection points between the coil bodies 123. In this regard, as described above, the conductor cross-sectional area of ​​the conductor wire material C2 of the second winding portion 71b is made smaller than that of the conductor wire material C1 of the first winding portion 71a, and the radial width dimension of the conductor wire material C2 of the second winding portion 71b is made the same as that of the conductor wire material C1 of the first winding portion 71a, but the circumferential width dimension is made smaller than that of the conductor wire material C1. This makes it possible to increase the number of turns in the second winding portion 71b while suppressing the disadvantage of an increase in the number of connection points between the coil bodies 123 due to an increase in the number of coil bodies 123 arranged radially.

[0070] (Other Embodiments) The above embodiment may be modified as follows, for example.

[0071] Only one of the conductor wires C1 and C2 of each of the winding portions 71a and 71b may be a bundled wire, or neither of the conductor wires C1 and C2 may be a bundled wire.

[0072] 16 shows a configuration in which the conductor wire C1 of the first winding portion 71a is bundled and the conductor wire C2 of the second winding portion 71b is solid wire rather than bundled wire. This configuration can effectively reduce eddy current loss in the first winding portion 71a, which is susceptible to leakage flux of high-frequency excitation magnetic flux from the stator 50. However, bundled wires are more likely to have variations in outer diameter than solid wires. Therefore, if the second winding portion 71b, which is wound around the radially inner side of the main pole 62, is bundled, there is a concern that dimensional variations may cause problems with winding the conductor wire in a relatively narrow space. In this regard, by using solid wire rather than bundled wire for the second winding portion 71b, problems with winding the conductor wire can be prevented.

[0073] In the above embodiment, the conductor cross-sectional area of ​​the conductor wire C2 of the second winding portion 71b is smaller than the conductor cross-sectional area of ​​the conductor wire C1 of the first winding portion 71a by making the length of the long side of the conductor wire C2 the same as that of the conductor wire C1 and making the length of the short side smaller (see FIG. 10 ). However, this may be changed. For example, the conductor wire C2 may have the same length of the short side as that of the conductor wire C1 but have a shorter length of the long side. Alternatively, the conductor wire C2 may have both shorter lengths of the long side and the short side smaller than that of the conductor wire C1.

[0074] In the above embodiment, the conductor material of each of the winding portions 71 a, 71 b is a rectangular wire, but this may be changed. For example, the conductor material of one of the winding portions 71 a, 71 b may be a rectangular wire and the conductor material of the other may be a round wire. Alternatively, the conductor material of both may be a round wire.

[0075] In the above embodiment, the ends of the conductors of the coil bodies 121, 123 in each winding portion 71a, 71b are joined by welding, but this may be changed to a configuration in which the ends of the conductors are joined by crimping or bolting, for example.

[0076] The winding portions 71 a and 71 b may be made of the same conductor material. Specifically, the conductor material of the winding portions 71 a and 71 b may be, for example, aluminum, copper, or CNT.

[0077] The rotating electric machine is not limited to an inner rotor type rotating electric machine, and may be an outer rotor type rotating electric machine. In an outer rotor type rotating electric machine, the stator 50 is disposed radially inward and the rotor 60 is disposed radially outward. In this case, the main pole portion 62 protrudes radially inward from the annular yoke portion of the rotor core. In the field winding 70, the first winding portion 71a is preferably disposed radially inward (toward the stator 50), and the second winding portion 71b is preferably disposed radially outward (away from the stator).

[0078] In the stator 50, the stator core may be a teethless core that does not have teeth.

[0079] The rotating electric machine is not limited to a rotating electric machine used as an in-vehicle main engine, but may be, for example, a rotating electric machine used as an ISG (Integrated Starter Generator) that is both a motor and a generator.

[0080] The moving body on which the rotating electric machine system is mounted is not limited to a vehicle, but may be, for example, an aircraft or a ship. Furthermore, the rotating electric machine system is not limited to a system mounted on a moving body, but may be a stationary system.

[0081] Although the present disclosure has been described with reference to the embodiments, it is understood that the present disclosure is not limited to the embodiments or structures. The present disclosure also encompasses various modifications and equivalent modifications. In addition, various combinations and forms, including only one element, more than one element, or less than one element, are also within the scope and spirit of the present disclosure.

Claims

1. A wound field type rotating electric machine (40) comprising: a stator (50) having a stator winding (52); a rotor core (61) having main pole portions (62) provided for each magnetic pole arranged in the circumferential direction and projecting in the radial direction; and a rotor (60) having a field winding (70) wound around the main pole portions, in which a high frequency current flows through the stator winding for inducing a field current in the field winding, the field winding having a series connection of a first winding portion (71a) and a second winding portion (71b), each of which is wound around each of the main pole portions with the first winding portion on the side closer to the stator and the second winding portion on the side farther from the stator in the radial direction, the first winding portion being connected in series to a capacitor (91) to form a series resonant circuit, and the second winding portion being connected in parallel to the capacitor to form a parallel resonant circuit, a second winding portion having a larger number of turns than the first winding portion, and a conductor material used for the second winding portion having a smaller conductor cross-sectional area than a conductor material used for the first winding portion.

2. A wound field type rotating electric machine as set forth in claim 1, wherein the conductor material of at least one of said first winding section and said second winding section is a bundled wire made of a plurality of strands bundled together.

3. A wound-field type rotating electric machine as described in claim 1, which has an inner rotor structure with the stator disposed radially outside and the rotor disposed radially inside, wherein the conductor material of the first winding section is a bundled wire made of a plurality of strands bundled together, and the conductor material of the second winding section is not the bundled wire.

4. A wound field type rotating electric machine as claimed in any one of claims 1 to 3, wherein each of the conductor materials of the first winding section and the second winding section is a flat conductor wire whose conductor cross section is rectangular with long sides and short sides, and the long sides of each of the conductor materials are joined to each other to connect the winding sections in series, and the conductor material of the second winding section has the same length of its long sides and a smaller length of its short sides than the conductor material of the first winding section.

5. A wound field type rotating electric machine as claimed in any one of claims 1 to 3, wherein the first winding section and the second winding section have coil bodies (121, 123) formed by winding conductor material around each of the main pole sections, and each coil body for each of the main pole sections is connected in series; in the second winding section, the coil bodies are arranged in multiple rows in the radial direction around the main pole section, and the coil bodies are connected to each other in each row; and the conductor material of the second winding section has the same radial width dimension and a smaller circumferential width than the conductor material of the first winding section.

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