Rotating electrical machine

Abstract

In the present invention, three-phase currents supplied from a first inverter (51) and a third inverter (53) and three-phase currents supplied from a second inverter (52) and a fourth inverter (54) each have a predetermined current phase difference. First coil bodies (Ua, Va, Wa) of the respective phases are formed by winding a first stator winding (321) or a third stator winding (323) around first teeth. Second coil bodies (Ub, Vb, Wb) of the respective phases are formed by winding a second stator winding (322) or a fourth stator winding (324) around second teeth. Third coil bodies (Uc, Vc, Wc) of the respective phases are formed by winding the first stator winding (321) or the third stator winding (323) of any one of the three phases, and the second stator winding (322) or the fourth stator winding (324) of any one of the three phases, around third teeth.

Description

rotating electrical machines CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Application No. 2023-194966, filed on November 16, 2023, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a rotating electric machine.

[0003] In a conventional rotary electric machine having two sets of stator windings to which three-phase currents are supplied from two inverters, a technique for reducing sixth and twelfth electrical order torque ripples by phase-shift current application between the two inverters has been known. For example, the rotary electric machine disclosed in Patent Document 1 includes coil bodies Ua, Va, and Wa formed by winding a first stator winding of each phase around a first tooth, coil bodies Ub, Vb, and Wb formed by winding a second stator winding of each phase around a second tooth, and coil bodies Uc, Vc, and Wc formed by winding the first stator winding of any one phase and the second stator winding of any one phase around a third tooth. Two inverters are used to energize the first and second stator windings with a phase difference of 20° or 40° electrical angle, and a magnetomotive force is generated in the coil bodies Uc, Vc, and Wc by adding together magnetomotive forces with a combined phase difference of 80° or 40°, thereby canceling out the sixth and twelfth electrical harmonic components.

[0004] Patent Document 2 discloses a motor drive system in which a rotating electric machine (motor) having the configuration described in Patent Document 1 is driven by two inverters.

[0005] Patent No. 7103299 Patent No. 7226809

[0006] In this specification, a series of units including an inverter and a stator winding to which a three-phase current is supplied from the inverter is referred to as a "system." Patent Documents 1 and 2 disclose a "two-system" rotating electric machine and motor drive system in which two inverters supply three-phase current to two corresponding sets of stator windings. In a two-system redundant system, even if the inverter or stator winding of one system fails, the other system can be used to continue driving the rotating electric machine (motor). For this reason, this system is applied to systems that require reliability, such as an electric power steering device for a vehicle.

[0007] However, in the future, there will be a demand for even greater system redundancy in order to further improve safety and reliability. For example, when realizing a "four-system" system, although it is easy to increase the number of inverters from two to four, the conventional technology disclosed in Patent Document 1 cannot be used as is for the configuration of the stator windings of the rotating electrical machine.

[0008] An object of the present disclosure is to provide a rotating electric machine to which a three-phase current is supplied from an inverter, in which torque ripples of the electrical sixth and twelfth orders are reduced and redundancy is increased.

[0009] The rotating electric machine according to the present disclosure comprises a rotor having a plurality of magnetic poles with alternating polarity in the circumferential direction and rotating integrally with the rotating shaft, and a stator having a three-phase stator winding and a stator core having a plurality of teeth arranged at predetermined intervals in the circumferential direction and around which the stator winding is wound.

[0010] The stator windings include a first stator winding supplied with three-phase current from a first inverter, a second stator winding supplied with three-phase current from a second inverter, a third stator winding supplied with three-phase current from a third inverter, and a fourth stator winding supplied with three-phase current from a fourth inverter.

[0011] The three-phase current supplied from the first inverter and the three-phase current supplied from the third inverter are conducted with the same current amplitude and phase. The three-phase current supplied from the second inverter and the three-phase current supplied from the fourth inverter are conducted with the same current amplitude and phase. The three-phase currents supplied from the first inverter and the third inverter and the three-phase currents supplied from the second inverter and the fourth inverter have a predetermined current phase difference, respectively. The predetermined current phase difference is set, for example, within a range of 15 to 25 degrees or a range of 35 to 45 degrees.

[0012] The rotating electric machine includes a first coil body of U phase, a first coil body of V phase, a first coil body of W phase, a second coil body of U phase, a second coil body of V phase, a second coil body of W phase, a third coil body of U phase, a third coil body of V phase, and a third coil body of W phase.

[0013] The U-phase first coil body is formed by winding the first or third stator winding of the U-phase among the three phases around the first teeth. The V-phase first coil body is formed by winding the first or third stator winding of the V-phase among the three phases around the first teeth. The W-phase first coil body is formed by winding the first or third stator winding of the W-phase among the three phases around the first teeth.

[0014] The U-phase second coil body is formed by winding the second stator winding or the fourth stator winding of the U-phase of the three phases around the second teeth. The V-phase second coil body is formed by winding the second stator winding or the fourth stator winding of the V-phase of the three phases around the second teeth. The W-phase second coil body is formed by winding the second stator winding or the fourth stator winding of the W-phase of the three phases around the second teeth.

[0015] The U-phase third coil body is formed by winding the first stator winding or the third stator winding of any one of the three phases and the second stator winding or the fourth stator winding of any one of the three phases around the third teeth. The V-phase third coil body is formed by winding the first stator winding or the third stator winding of any one of the three phases and the second stator winding or the fourth stator winding of any one of the three phases around the third teeth. The W-phase third coil body is formed by winding the first stator winding or the third stator winding of any one of the three phases and the second stator winding or the fourth stator winding of any one of the three phases around the third teeth.

[0016] The rotating electric machine is set to have the combined phase difference [pd1] or [pd2] below so as to achieve the target [G1] or [G2] below. The "predetermined phase range including 20 degrees in electrical angle" below includes, for example, electrical angles of 20 degrees and 40 degrees.

[0017] [G1] The phase difference between the magnetomotive force of the third coil body of each phase and the magnetomotive force of the first coil body of each phase, and the phase difference between the magnetomotive force of the second coil body of each phase and the magnetomotive force of the third coil body of each phase, are within a predetermined phase range that includes 20 electrical degrees.

[0018] [G2] The phase differences of the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase relative to the magnetomotive force of the first coil body of each phase, and the phase differences of the magnetomotive force of the third coil body of each phase relative to the magnetomotive force of the second coil body of each phase, are within a predetermined phase range that includes 20 electrical degrees.

[0019] [pd1] The combined phase difference between the magnetomotive force generated by the partial winding of the first stator winding or the third stator winding wound around the third tooth and the magnetomotive force generated by the partial winding of the second stator winding or the fourth stator winding wound around the third tooth.

[0020] [pd2] The combined phase difference between the current flowing through the partial winding of the first stator winding or the third stator winding wound around the third tooth and the current flowing through the partial winding of the second stator winding or the fourth stator winding wound around the third tooth.

[0021] This disclosure provides a four-system rotating electric machine in which four inverters supply three-phase current to four corresponding sets of stator windings. For this rotating electric machine, a group of the first and third systems and a group of the second and fourth systems are energized with a predetermined phase difference in current. By setting the combined phase difference [pd1] or [pd2] for the magnetomotive force or current in the third coil body, the sixth and twelfth electrical harmonic components are canceled. This reduces torque ripple and enhances redundancy.

[0022] 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 four-path motor drive system, Fig. 2 is a schematic axial cross-sectional view of the motor, Fig. 3 is a schematic cross-sectional view taken along line III-III in Fig. 2 showing an example of the arrangement of lead wires of the stator windings, Fig. 4 is a diagram showing an example of the configuration of four paths (first to fourth) of stator windings, Fig. 5 is a radial cross-sectional view showing the circumferential configuration of the stator and rotor, and Fig. 6 is a diagram showing a configuration of a four-path motor drive system in which current is passed through the first coil bodies Ua, Va, Wa and the second coil bodies Ub, Vb, Wb by 20° phase difference current passing and 40° phase difference current passing. 7 is a diagram illustrating the phases of three-phase currents, FIG. 7 is a diagram illustrating the current and magnetomotive force added together in the third coil bodies Uc, Vc, and Wc when energized with a 20° phase difference, FIG. 8 is a diagram illustrating the current and magnetomotive force added together in the third coil bodies Uc, Vc, and Wc when energized with a 40° phase difference, FIG. 9 is a table illustrating an example of the arrangement of partial windings of four stator windings in a 14P18S motor, FIG. 10 is a radial cross-sectional view of the 14P18S motor of the first embodiment, and FIG. 11 is a radial cross-sectional view of the 14P18S motor of the second embodiment. 12 is a radial cross-sectional view of a 14P18S motor of the third embodiment, FIG. 13 is a radial cross-sectional view of a 14P18S motor of the fourth embodiment, FIG. 14 is a table showing an example of the layout of partial windings of four-system stator windings in a 22P18S motor, FIG. 15 is a radial cross-sectional view of a 22P18S motor of the fifth embodiment, FIG. 16 is a table showing an example of the layout of partial windings of four-system stator windings in a 16P18S motor, FIG. 17 is a radial cross-sectional view of a 16P18S motor of the sixth embodiment, and FIG. 18 is a radial cross-sectional view of a 16P18S motor of the seventh embodiment, FIG. 19 is a table showing an example of the arrangement of partial windings of four systems of stator windings in a 20P18S motor, FIG. 20 is a radial cross-sectional view of a 20P18S motor of the eighth embodiment, FIG. 21 is a radial cross-sectional view of a 28P36S motor of the ninth embodiment, FIG. 22 is a diagram showing another example of the arrangement of lead wires of the stator windings, FIG. 23 is a diagram showing another example of the arrangement of lead wires of the stator windings, and FIG. 24 is a diagram showing another example of the arrangement of lead wires of the stator windings.

[0023] Several embodiments of a rotating electric machine will be described with reference to the drawings. The following first to ninth embodiments will be collectively referred to as "the present embodiment." Substantially identical components in several embodiments will be assigned the same reference numerals, and description thereof will be omitted. The rotating electric machine of the present embodiment is applied to, for example, an electric power steering device of a vehicle, and is a motor that outputs steering assist torque, and is configured, for example, by a permanent magnet three-phase brushless motor. In the following description of the embodiments, "motor 10" corresponds to the rotating electric machine. Furthermore, "degrees," which are the unit of electrical angle or phase, will be expressed as "°."

[0024] [Motor Drive System] First, referring to Figure 1, the overall configuration of a four-system motor drive system that drives a motor 10 of this embodiment will be described. In this specification, a series of units including an inverter and a stator winding to which three-phase current is supplied from the inverter is referred to as a "system." A four-system system is a system in which four units are provided redundantly. The four-system motor drive system includes a control device 50 having four inverters 51 to 54, and a motor 10 having four sets of stator windings 321 to 324. Below, "first inverter 51" and "second stator winding 322" mean "inverter 51 of the first system" and "stator winding 322 of the second system," respectively.

[0025] The inverters 51 to 54 are configured with switching elements (e.g., MOSFETs) in upper and lower arms of a bridge-connected three phases (i.e., U phase, V phase, and W phase). The inverters 51 to 54 perform switching operations in accordance with drive signals commanded by a driver of the control device 50, thereby converting the DC power of the batteries BT1 and BT2 into three-phase AC power and supplying three-phase current to the stator windings 321 to 324.

[0026] 1, the first inverter 51 and the second inverter 52 are connected in parallel to a common battery BT1, and the third inverter 53 and the fourth inverter 54 are connected in parallel to a common battery BT2. Alternatively, the four inverters 51 to 54 may be connected to four batteries, respectively. Furthermore, if the possibility of battery failure or depletion is low, the four inverters 51 to 54 may be connected in parallel to one battery.

[0027] The first stator winding 321 is supplied with three-phase currents U1, V1, and W1 from the first inverter 51. The second stator winding 322 is supplied with three-phase currents U2, V2, and W2 from the second inverter 52. The third stator winding 323 is supplied with three-phase currents U3, V3, and W3 from the third inverter 53. The fourth stator winding 324 is supplied with three-phase currents U4, V4, and W4 from the fourth inverter 54. In each of the stator windings 321 to 324, the three-phase windings are connected at neutral points Q1 to Q4. Note that the three-phase stator windings are not limited to being Y-connected (star-connected), but may be configured with a delta connection.

[0028] The conductors connecting the stator windings of each phase to the corresponding inverter are called "lead wires." The U-phase, V-phase, and W-phase lead wires are designated by the symbols A, B, and C, respectively. For example, the lead wire of the first stator winding 321 of the U phase is designated by the symbol "A1," the lead wire of the second stator winding 322 of the V phase is designated by the symbol "B2," and the lead wire of the third stator winding 323 of the W phase is designated by the symbol "C3."

[0029] The current flowing through each phase of each system is detected by a current sensor (not shown). The rotation angle of the motor 10 is detected by an angle sensor 56 (see FIG. 2). The control device 50 controls the operation of the inverters 51 to 54 by feedback control using information on the phase current and rotation angle.

[0030] Here, the three-phase currents U1, V1, and W1 supplied from the first inverter 51 and the three-phase currents U3, V3, and W3 supplied from the third inverter 53 are supplied with the same current amplitude and phase. The three-phase currents U2, V2, and W2 supplied from the second inverter 52 and the three-phase currents U4, V4, and W4 supplied from the fourth inverter 54 are supplied with the same current amplitude and phase.

[0031] The three-phase currents U1, V1, W1, U3, V3, and W3 supplied from the first inverter 51 and the third inverter 53 and the three-phase currents U2, V2, W2, U4, V4, and W4 supplied from the second inverter 52 and the fourth inverter 54 have a predetermined current phase difference. Preferably, the "predetermined current phase difference" is 20° or 40°. The 20° current phase difference may be set "in the range of 15 to 25°," and the 40° current phase difference may be set "in the range of 35 to 45°."

[0032] As will be described later, a magnetomotive force proportional to the product of the current and the number of turns is generated for each tooth around which each stator winding 321-324 is wound. The phase of the magnetomotive force is equal to the current phase. The motor 10 outputs a sum of torques generated on the same axis by the magnetomotive forces generated by the four systems of stator windings 321-324 wound around each tooth.

[0033] [Motor Configuration] Next, the configuration of the motor 10 will be described with reference to Figures 2 to 5. Figure 2 schematically illustrates only the stator 30, rotor 40, and substrate 55 to which lead wires A1 to A4, B1 to B4, and C1 to C4 are connected. Other components of a typical motor, such as the housing and bearings, are not shown or described.

[0034] In a mechatronically integrated motor in which the control device 50 is integrally formed, the control device 50 is mounted on a substrate 55 as shown by the dashed line. However, the motor 10 of this embodiment is not limited to a mechatronically integrated motor, and may be a mechatronically separated motor in which the control device 50 is provided separately and is connected by a cable.

[0035] The stator 30 and rotor 40 are disposed coaxially with respect to the center line O of the rotating shaft 11. In the following description, the terms axial direction, radial direction, and circumferential direction refer to the axial direction, radial direction, and circumferential direction of the rotating shaft 11, respectively. The stator 30 has an annular stator core 31 and a three-phase stator winding 32. The stator winding 32 includes four systems of stator windings 321 to 324. The stator core 31 is formed, for example, by laminating thin magnetic steel plates. Three-phase currents are supplied to the first to fourth stator windings 321 to 324 from the first to fourth inverters 51 to 54, respectively, and magnetomotive forces are generated. This generates a rotating magnetic field in the stator 30.

[0036] The rotor 40 is rotatably disposed radially inside the stator 30. The rotor 40 has a rotor core 41 made of a magnetic material and a plurality of magnetic poles 42 fixed to the rotor core 41 and with alternating polarities in the circumferential direction. The magnetic poles 42 are made of permanent magnets. The rotating shaft 11 is fixed to the center of the rotor core 41. The rotor 40 rotates integrally with the rotating shaft 11 due to the rotating magnetic field generated by the stator 30. The circumferential configuration of the stator 30 and the rotor 40 will be described later with reference to FIG. 5 .

[0037] A sensor magnet 12 is fixed to the end of the rotating shaft 11 on the substrate 55 side. An angle sensor 56 such as a Hall element or MR element is provided at a location facing the sensor magnet 12 on the surface of the substrate 55 on the stator 30 and rotor 40 side (the bottom surface in FIG. 2 ). The angle sensor 56 detects the rotation angle of the rotor 40 based on changes in the magnetic field of the sensor magnet 12. In order to improve the detection accuracy of the angle sensor 56, it is necessary to suppress the influence of disturbance magnetic flux.

[0038] 3 shows an example of the arrangement of lead wires A1 to A4, B1 to B4, and C1 to C4 of the stator windings 321 to 324 as viewed from the side of the circuit board 55. Lead wires A1, B1, and C1 of the first stator winding 321 connected to the first inverter 51 and lead wires A3, B3, and C3 of the third stator winding 323 connected to the third inverter 53 are arranged so that each phase is symmetrical about the rotating shaft 11. Lead wires A2, B2, and C2 of the second stator winding 322 connected to the second inverter 52 and lead wires A4, B4, and C4 of the fourth stator winding connected to the fourth inverter 54 are arranged so that each phase is symmetrical about the rotating shaft 11. The arrangement of the lead lines A2, B2, and C2 of the second system and the lead lines A4, B4, and C4 of the fourth system shown in Fig. 3 is referred to as "2 left, 4 right." The lead lines A2 and A4, B2 and B4, and C2 and C4 may be swapped with respect to the arrangement shown in Fig. 3 to form an arrangement of "4 left, 2 right."

[0039] Here, "symmetrical about the rotation axis 11" strictly means "symmetrical about the center line O of the rotation axis 11." By arranging the leads carrying currents of the same amplitude and phase at equal distances from the rotation axis 11, disturbance magnetic flux is canceled on the rotation axis 11. This minimizes errors caused by disturbance magnetic flux in the angle sensor 56, which detects the rotation angle of the rotor 40 based on changes in the magnetic field of the sensor magnet 12.

[0040] The leads A1, B1, and C1 of the first stator winding 321 and the leads A3, B3, and C3 of the third stator winding 323 are collectively referred to as the "first lead group ABC13." The leads A2, B2, and C2 of the second stator winding 322 and the leads A4, B4, and C4 of the fourth stator winding are collectively referred to as the "second lead group ABC24." In the arrangement example shown in Figure 3, the center line M13 of the first lead group ABC13 and the center line M24 of the second lead group ABC24 are perpendicular to each other.

[0041] Furthermore, the distances between the symmetrically arranged lead wires of the same phase in the first lead wire group ABC13 and the second lead wire group ABC24 are represented as opposing distances d13 and d24. In the arrangement example of Fig. 3, the opposing distances d13 and d24 between the lead wire groups ABC13 and ABC24 are equal. In other words, the four lead wire systems A1 to A4, B1 to B4, and C1 to C4 are arranged with 90° rotational symmetry around the rotation axis 11. This achieves an arrangement with excellent symmetry.

[0042] However, it is not essential that the center lines M13 and M24 of the lead line groups ABC13 and ABC24 be perpendicular to each other or that the opposing distances d13 and d24 of the lead line groups ABC13 and ABC24 be equal. Arrangements of the lead lines A1 to A4, B1 to B4, and C1 to C4 other than the arrangement example in Figure 3 will be described later as other embodiments with reference to Figures 22 to 24.

[0043] Next, the wiring of each stator winding 321 to 324 will be described with reference to FIG. 4. The "+" and "-" suffixes at the end of the symbols indicate the direction of the magnetomotive force generated according to the winding direction of the partial winding relative to the same current direction. A winding pattern of a partial winding that generates a magnetomotive force in the forward direction is called "forward winding," while a winding pattern of a partial winding that generates a magnetomotive force in the reverse direction is called "reverse winding." There is a phase difference of 180 electrical degrees between the current flowing through a forward-wound (+) partial winding and the current flowing through a reverse-wound (-) partial winding. In this embodiment, the desired magnetomotive force phase difference can be set by combining and arranging a forward-wound partial winding and a reverse-wound partial winding on each tooth.

[0044] The first stator winding 321 has U-phase partial windings U1+ and U1- connected in series, V-phase partial windings V1+ and V1- connected in series, and W-phase partial windings W1+ and W1- connected in series. One end of the series-connected assembly is connected to a neutral point Q1. At the other end of the series-connected assembly, the U-phase, V-phase, and W-phase partial windings are connected to lead wires A1, B1, and C1, respectively. The lead wires A1, B1, and C1 are connected to a first inverter 51.

[0045] Similarly, the second stator winding 322 has U-phase partial windings U2+ and U2- connected in series, V-phase partial windings V2+ and V2- connected in series, and W-phase partial windings W2+ and W2- connected in series. One end of the series-connected assembly is connected to the neutral point Q2. At the other end of the series-connected assembly, the U-phase, V-phase, and W-phase partial windings are connected to leads A2, B2, and C2, respectively. Leads A2, B2, and C2 are connected to the second inverter 52.

[0046] Similarly, the third stator winding 323 has U-phase partial windings U3+ and U3- connected in series, V-phase partial windings V3+ and V3- connected in series, and W-phase partial windings W3+ and W3- connected in series. One end of the series-connected assembly is connected to the neutral point Q3. At the other end of the series-connected assembly, the U-phase, V-phase, and W-phase partial windings are connected to leads A3, B3, and C3, respectively. Leads A3, B3, and C3 are connected to the third inverter 53.

[0047] Similarly, the fourth stator winding 324 has U-phase partial windings U4+ and U4- connected in series, V-phase partial windings V4+ and V4- connected in series, and W-phase partial windings W4+ and W4- connected in series. One end of the series-connected assembly is connected to the neutral point Q4. At the other end of the series-connected assembly, the U-phase, V-phase, and W-phase partial windings are connected to leads A4, B4, and C4, respectively. Leads A4, B4, and C4 are connected to the fourth inverter 54.

[0048] Referring to FIG. 5 , the circumferential configuration of the stator 30 and rotor 40 will be described using a 14-pole, 18-slot IPM motor as an example. Hereinafter, the number of magnetic poles on the rotor 40 and the number of slots between the teeth of the stator 30 will be referred to as "P" and "S," respectively. For example, 14 poles and 18 slots will be represented as "14P18S." The 14P18S configuration is a representative configuration of this embodiment and corresponds to the first to fourth embodiments. Note that while FIG. 5 shows a radial cross-section of the stator 30 and rotor 40, cross-sectional hatching has been omitted for clarity. Furthermore, the cross-section of the stator winding 32 is typically represented as multiple circles, but is shown as a rectangular area without hatching for illustrative purposes. Note that the size of the rectangular area does not correlate with the cross-sectional area of ​​the actual coil body.

[0049] First, the rotor 40 will be described. In a 14P18S motor, 14 magnetic poles 42 are fixed to the rotor core 41 so that the polarities alternate in the circumferential direction. The 14 magnetic poles 42 form seven magnetic pole pairs. In an IPM motor, the magnetic poles 42 are embedded in the rotor core 41. However, this is not limited to an IPM motor; an SPM motor in which the magnetic poles 42 are provided on the surface of the rotor core 41 may also be used.

[0050] Next, regarding the stator 30, the stator core 31 has an annular back yoke 33 and a plurality of teeth T1 to T18 that protrude radially inward from the back yoke 33. The plurality of teeth T1 to T18 are provided at predetermined intervals in the circumferential direction, and slots 35 are formed between adjacent teeth. The number of teeth is equal to the number of slots 35, and is 18 for the 14P18S. In the radial cross-sectional views below, tooth T1 is shown on the right side of the stator 30, and the remaining 17 teeth T2 to T18 are shown counterclockwise from tooth T1 at equal intervals in the circumferential direction.

[0051] The 18 teeth T1 to T18 are arranged circumferentially at intervals of 20° mechanical angle. The intervals of 20° mechanical angle are converted to electrical angle based on the number of magnetic poles P, i.e., the number of magnetic pole pairs (P / 2). Since a mechanical angle of {360 / (P / 2)}° corresponds to an electrical angle of 360°, a mechanical angle of 20° is converted to an electrical angle of (P×10)°. In the 14P18S, the interval between adjacent teeth in the circumferential direction is an electrical angle of 140°.

[0052] The stator winding 32 is housed in the slots 35 and wound around the teeth T1 to T18. The stator winding 32 is wound around each of the teeth T1 to T18 to form a "coil body." The motor 10 has three types of coil bodies for each phase: a first coil body, a second coil body, and a third coil body. That is, the motor 10 has a U-phase first coil body Ua, a V-phase first coil body Va, a W-phase first coil body Wa, a U-phase second coil body Ub, a V-phase second coil body Vb, a W-phase second coil body Wb, a U-phase third coil body Uc, a V-phase third coil body Vc, and a W-phase third coil body Wc.

[0053] The first coil bodies Ua, Va, and Wa are formed by winding the first stator winding 321 or the third stator winding 323 of the U-phase, V-phase, or W-phase of the three phases around the first teeth. In the example of Fig. 5, the teeth T1, T4, T7, T10, T13, and T16 correspond to the first teeth. The first coil bodies Ua, Va, and Wa are illustrated as a pair of rectangular areas on either side of the first teeth.

[0054] The second coil bodies Ub, Vb, and Wb are formed by winding the second stator winding 322 or the fourth stator winding 324 of the U-phase, V-phase, and W-phase, respectively, around the second teeth. In the example of Fig. 5, the teeth T2, T5, T8, T11, T14, and T17 correspond to the second teeth. The second coil bodies Ub, Vb, and Wb are illustrated as a pair of rectangular areas on either side of the second teeth.

[0055] The third coil bodies Uc, Vc, and Wc are formed by winding the first stator winding 321 or the third stator winding 323 of any one of the three phases and the second stator winding 322 or the fourth stator winding 324 of any one of the three phases around the third teeth. In the example of Figure 5, the teeth T3, T6, T9, T12, T15, and T18 correspond to the third teeth. The third coil bodies Uc, Vc, and Wc are illustrated as two pairs of rectangular areas on either side of the third teeth, i.e., the radially inner area and the radially outer area.

[0056] 5 does not show the specific phase and system arrangements of the stator windings 321 to 324 wound around each of the teeth T1 to T18. The following Figures 9 to 21 show examples of the phase and system arrangements of the stator windings 32 wound around each tooth in accordance with the current phase difference between the first and third inverters 51, 53 and the second and fourth inverters 52, 54, and the summed magnetomotive force phase difference.

[0057] 6 to 8, the phase difference energization by the four inverters 51 to 54 and the addition of the magnetomotive forces in the third coil bodies Uc, Vc, and Wc will be described. A current energization method in which the amplitudes of the currents supplied by the first and third inverters 51, 53 and the second and fourth inverters 52, 54 are equal and the current phase difference is set to 20° will be referred to as "20° phase difference energization," and a current energization method in which the current phase difference is set to 40° will be referred to as "40° phase difference energization."

[0058] 6 shows the phases of currents supplied to the first coil bodies Ua, Va, Wa and the second coil bodies Ub, Vb, Wb in the case of 20° phase difference current supply and 40° phase difference current supply. The phases of the three-phase currents supplied to the first coil bodies Ua, Va, Wa from the first inverter 51 and the third inverter 53 are set as the reference phase. For example, for the U phase, the current phase of 0° in the forward winding partial windings U1+ and U3+ of the first and third stator windings 321 and 323 is set as the reference phase. The phases of the three-phase currents supplied to the second coil bodies Ub, Vb, Wb from the second inverter 52 and the fourth inverter 54 are set to have a current phase difference from the reference phase of 20° or 40°.

[0059] The three-phase currents supplied to the first coil bodies Ua, Va, and Wa from the first inverter 51 and the third inverter 53 are expressed by equations (1.1) to (1.6). The current amplitude I common to the four systems is called the fundamental current amplitude I.

[0060] U1+=U3+=Isin(θ)...(1.1) W1-=W3-=Isin(θ-60)...(1.2) V1+=V3+=Isin(θ-120)...(1.3) U1-=U3-=Isin(θ-180)...(1.4) W1+=W3+=Isin(θ-240)...(1.5) V1-=V3-=Isin(θ-300)...(1.6)

[0061] The three-phase currents supplied to the second coil bodies Ub, Vb, and Wb from the second inverter 52 and the fourth inverter 54 by the 20° phase difference energization are expressed by equations (2.1) to (2.6).

[0062] U2+=U4+=Isin(θ-20)...(2.1) W2-=W4-=Isin(θ-80)...(2.2) V2+=V4+=Isin(θ-140)...(2.3) U2-=U4-=Isin(θ-200)...(2.4) W2+=W4+=Isin(θ-260)...(2.5) V2-=V4-=Isin(θ-320)...(2.6)

[0063] The three-phase currents supplied to the second coil bodies Ub, Vb, and Wb from the second inverter 52 and the fourth inverter 54 by the 40° phase difference energization are expressed by equations (3.1) to (3.6).

[0064] U2+=U4+=Isin(θ-40)...(3.1) W2-=W4-=Isin(θ-100)...(3.2) V2+=V4+=Isin(θ-160)...(3.3) U2-=U4-=Isin(θ-220)...(3.4) W2+=W4+=Isin(θ-280)...(3.5) V2-=V4-=Isin(θ-340)...(3.6)

[0065] As will be explained below regarding the summation of the currents and magnetomotive forces in the third coil bodies Uc, Vc, and Wc, the phase of the three-phase current generated by summing with 20° phase difference current is the same as the current phase with 40° phase difference current, and the phase of the three-phase current generated by summing with 40° phase difference current is the same as the current phase with 20° phase difference current. In either phase difference current, the phase difference of the current flowing through the second coil bodies Ub, Vb, and Wb and the third coil bodies Uc, Vc, and Wc relative to the current flowing through the first coil body Ua, Va, and Wa is 20° on one side and 40° on the other side.

[0066] This cancels out the sixth and twelfth electrical harmonic components, making it possible to reduce the sixth and twelfth electrical torque ripples.

[0067] 7 and 8, the phase difference and amplitude of the current and magnetomotive force added together in the third coil bodies Uc, Vc, and Wc when energized with a 20° phase difference and when energized with a 40° phase difference will be described. The combined combination of partial windings of the stator winding 32 shown in Fig. 7 corresponds to the tooth T9, which is the third tooth in the first and second embodiments. The combined combination of partial windings of the stator winding 32 shown in Fig. 8 corresponds to the tooth T14, which is the third tooth in the third and fourth embodiments. A general explanation will be given here, and details will be provided later in each embodiment.

[0068] The current flowing through the partial winding of the first stator winding 321 or the third stator winding 323 wound around the third tooth, and the current flowing through the partial winding of the second stator winding 322 or the fourth stator winding 324 wound around the third tooth are referred to as the "first current vector a" and the "second current vector b," respectively. Furthermore, the current flowing through the third coil bodies Uc, Vc, and Wc, obtained by adding up the current vector a and the current vector b, is referred to as the "summed current vector s." In Figures 7 and 8, the current vector a, the current vector b, and the summed current vector s are represented by vector symbols.

[0069] The amplitudes of the first current vector a and the second current vector b are equal to the fundamental current amplitude I. Furthermore, the current phase difference between the first current vector a and the second current vector b is defined as the "total phase difference." Because the phase of the magnetomotive force coincides with the current phase, the "total phase difference" is also the phase difference between the phase of the magnetomotive force due to the first current vector a and the phase of the magnetomotive force due to the second current vector b. In other words, the "total phase difference" is defined in two ways: [pd1] and [pd2] as follows.

[0070] [pd1] The combined phase difference between the magnetomotive force generated by the partial winding of the first stator winding 321 or the third stator winding 323 wound around the third tooth and the magnetomotive force generated by the partial winding of the second stator winding 322 or the fourth stator winding 324 wound around the third tooth.

[0071] [pd2] The combined phase difference between the current flowing through the partial winding of the first stator winding 321 or the third stator winding 323 wound around the third tooth and the current flowing through the partial winding of the second stator winding 322 or the fourth stator winding 324 wound around the third tooth.

[0072] These total phase differences [pd1] and [pd2] are set to the following target [G1] or [G2]. The "predetermined phase range including 20° electrical angle" below includes electrical angles of 20° and 40°.

[0073] [G1] The phase differences of the magnetomotive forces of the third coil bodies Uc, Vc, Wc of each phase relative to the magnetomotive forces of the first coil bodies Ua, Va, Wa of each phase, and the phase differences of the magnetomotive forces of the second coil bodies Ub, Vb, Wb of each phase relative to the magnetomotive forces of the third coil bodies Uc, Vc, Wc of each phase, are within a predetermined phase range that includes 20° electrical angle.

[0074] [G2] The phase differences of the magnetomotive forces of the second coil bodies Ub, Vb, Wb of each phase relative to the magnetomotive forces of the first coil bodies Ua, Va, Wa of each phase, and the phase differences of the magnetomotive forces of the third coil bodies Uc, Vc, Wc of each phase relative to the magnetomotive forces of the second coil bodies Ub, Vb, Wb of each phase, are within a predetermined phase range that includes 20° electrical angle.

[0075] Hereinafter, the total phase difference of [pd1] will be referred to as the "magnetomotive force phase difference." In the description of the embodiment, the magnetomotive force phase difference will mainly be described as the total phase difference. The magnetomotive force phase difference is set to an electrical angle of 80° or an electrical angle of 40°. The magnetomotive force phase difference of an electrical angle of 80° may be set in the "range of electrical angles of 72 to 88°," and the magnetomotive force phase difference of an electrical angle of 40° may be set in the "range of electrical angles of 32 to 48°."

[0076] The amplitude of the magnetomotive force is proportional to the product of the current amplitude and the number of turns. Therefore, in order to match the amplitude of the magnetomotive force generated in the third coil body Uc, Vc, Wc by summation with the amplitude of the magnetomotive force generated in the first coil body Ua, Va, Wa and the second coil body Ub, Vb, Wb, the number of turns needs to be set so that the ratio of the number of turns is the reciprocal of the current amplitude ratio.

[0077] Here, the number of turns of the first stator winding 321 or the third stator winding 323 wound around the first teeth and the number of turns of the second stator winding 322 or the fourth stator winding 324 wound around the second teeth are each referred to as "Nab." The number of turns of the first stator winding 321 or the third stator winding 323 wound around the third teeth and the number of turns of the second stator winding 322 or the fourth stator winding 324 wound around the third teeth are each referred to as "Nc." By determining the ratio of the number of turns (Nab / Nc) based on the ratio of the current amplitude of the summed current vector s to the fundamental current amplitude I, magnetomotive forces of amplitudes equivalent to those of the first coil bodies Ua, Va, Wa and the second coil bodies Ub, Vb, Wb are generated in the third coil bodies Uc, Vc, Wc. This allows the motor 10 to output uniform torque.

[0078] The upper rows of Figures 7 and 8 show the sum of current vector a and current vector b when the magnetomotive force phase difference is 80°. In this case, the current amplitude of the summed U-phase current Us+ is 1.53 times the fundamental current amplitude I. Therefore, the number of turns on each of the first, second, and third teeth is set so as to satisfy the relationship "1.4≦Nab / Nc≦1.6", which is a range that includes "Nab / Nc=1.53".

[0079] The bottom rows of Figures 7 and 8 show the sum of current vector a and current vector b when the magnetomotive force phase difference is 40°. In this case, the current amplitude of the summed U-phase current Us+ is 1.88 times the fundamental current amplitude I. Therefore, the number of turns on each of the first, second, and third teeth is set so as to satisfy the relationship "1.9≦Nab / Nc≦2.0", which is a range that includes "Nab / Nc = 1.88".

[0080] When a two-system motor with a magnetic force phase difference set to 80° or 40° is energized with a 20° phase difference, the torque ripple of the electrical sixth and twelfth orders is reduced compared to when energized with the same phase difference. In this embodiment, by energizing a four-system motor with increased redundancy compared to a two-system motor with a 20° or 40° phase difference, the torque ripple of the electrical sixth and twelfth orders can be reduced.

[0081] [Motor Embodiments] Next, with reference to FIGS. 9 to 21 , specific examples of the arrangement of the partial windings of the four-system stator windings 321 to 324, which are determined according to the combination of the current phase difference and the magnetomotive force phase difference for each configuration of the number of magnetic poles and the number of slots, will be described as first to ninth embodiments.

[0082] The first to eighth embodiments have 18 slots. The first to fourth embodiments have 14P18S. The fifth embodiment has 22P18S, the sixth and seventh embodiments have 16P18S, and the eighth embodiment has 20P18S. The 14P18S and 22P18S have a configuration corresponding to "m = 1" in the general form of "the number of magnetic poles is (18 ± 4) × m (m is an integer greater than or equal to 1) and the number of slots is 18 × m." The 16P18S and 20P18S have a configuration corresponding to "n = 1" in the general form of "the number of magnetic poles is (18 ± 2) × n (n is an integer greater than or equal to 1) and the number of slots is 18 × n."

[0083] Compared to the 16P18S and 20P18S, the 14P18S and 22P18S have a better balance in that the electromagnetic force is distributed at 90° intervals at four locations in the circumferential direction, which is advantageous for suppressing noise and vibration.

[0084] (First embodiment) Fig. 9 shows a table of an example of the arrangement of partial windings of the four-system stator windings 321-324 in a 14P18S motor. Fig. 9 also shows the partial windings of the four-system stator windings 321-324, which are determined according to a combination of the electrical angle corresponding to each tooth T1-T18, the current phase difference between the systems, and the magnetomotive force, and the type of coil body. One type of partial winding is arranged on the first tooth and the second tooth. Two types of partial windings, shown before and after " / ", are arranged on the third tooth at different radial positions. The radial positions of the two types of partial windings wound around the third tooth may be interchanged.

[0085] The first embodiment is when the magnetomotive force phase difference is 80° with 20° phase difference energization. The second embodiment is when the magnetomotive force phase difference is 40° with 20° phase difference energization. The third embodiment is when the magnetomotive force phase difference is 80° with 40° phase difference energization. The fourth embodiment is when the magnetomotive force phase difference is 40° with 40° phase difference energization.

[0086] In the first embodiment, a U-phase first coil body Ua is formed by winding a U-phase partial winding U3+ (electrical angle 0°) of the third stator winding 323 around the first tooth T1. A V-phase second coil body Vb is formed by winding a V-phase partial winding V2+ (electrical angle 140° due to 20° phase difference energization) of the second stator winding 322 around the second tooth T2.

[0087] The W-phase third coil body Wc is formed by winding the W-phase partial winding W1+ (electrical angle 240°) of the first stator winding 321 and the V-phase partial winding V2- (electrical angle 320° due to energization with a 20° phase difference) of the second stator winding 322 around the third tooth T3. The average of the electrical angles of the two types of partial windings W1+ / V2- is the electrical angle of the third coil body Wc of 280°. The same applies to the remaining teeth T4 to T18. In this way, a total of 24 types of partial windings, consisting of the four systems of stator windings 321 to 324, are arranged on six first teeth, six second teeth, and six third teeth.

[0088] Fig. 10 shows the first embodiment when the magnetomotive force phase difference is 80° with current supplied with a 20° phase difference. Fig. 7 shows, as an example of a "magnetomotive force phase difference of 40°," the sum of the magnetomotive forces of the U-phase partial winding U1+ of the first stator winding 321 and the W-phase partial winding W4- of the fourth stator winding 324 in the third coil body Uc formed by being wound around the teeth T9 of the first embodiment.

[0089] The phase of the combined U-phase current Us+ is 40°, and the current amplitude is 1.53 times the fundamental current amplitude I flowing through the partial windings U1+ / W4- of the first and fourth stator windings 321, 324. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the first coil body Ua formed by the partial winding U1+ is 40°. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the second coil body Wb formed by the partial winding W4- is also 40°. This configuration provides the effect of canceling out the sixth and twelfth electrical harmonic components.

[0090] Incidentally, in the two-system comparative example, simply distributing the "partial winding of the first stator winding" to the partial windings of the first stator winding 321 and the third stator winding 323, and simply distributing the "partial winding of the second stator winding" to the partial windings of the second stator winding 322 and the fourth stator winding 324, may seem to be an extension of the comparative example. However, the key point of this embodiment lies in how the two systems of "partial winding of the first stator winding" are distributed to the partial windings of the first and third stator windings 321 and 323, and how the two systems of "partial winding of the second stator winding" are distributed to the partial windings of the second and fourth stator windings 322 and 324. Next, this point will be explained in detail.

[0091] 9, for example, the U-phase partial winding V2+ of the second stator winding 322 is wound around tooth T2, and the U-phase partial winding V2- of the second stator winding is wound around tooth T3, which is adjacent in the circumferential direction. In this way, in the first embodiment, the first and third teeth around which the first stator winding 321 of the same phase is wound are adjacent to each other, the second and third teeth around which the second stator winding 322 of the same phase is wound are adjacent to each other, the first and third teeth around which the third stator winding 323 of the same phase is wound are adjacent to each other, and the second and third teeth around which the fourth stator winding 324 of the same phase is wound are adjacent to each other. This facilitates wiring connections between the teeth.

[0092] In the 14P18S and 22P18S configurations, when the magnetomotive force phase difference is 80°, the first teeth and third teeth, and the second teeth and third teeth, on which stator windings of the same phase of the same system are wound, are adjacent in the circumferential direction. On the other hand, in the 16P18S and 20P18S configurations, when the magnetomotive force phase difference is 40°, the first teeth and third teeth, and the second teeth and third teeth, on which stator windings of the same phase of the same system are wound, are adjacent in the circumferential direction. Therefore, the same effects can be obtained in the first embodiment as well as the third, fifth, seventh, and ninth embodiments.

[0093] 10, both the first boundary line L1 and the second boundary line L2 are straight lines that pass through the rotation axis 11. Strictly speaking, "passing through the rotation axis 11" means "passing through the center line O of the rotation axis 11." The first boundary line L1 and the second boundary line L2 have different inclinations and intersect at the center line O of the rotation axis 11.

[0094] All of the first teeth and third teeth around which the first stator winding 321 of each phase is wound and all of the first teeth and third teeth around which the third stator winding 323 of each phase is wound are arranged in areas on opposite sides of the first boundary line L1. All of the second teeth and third teeth around which the second stator winding 322 is wound and all of the second teeth and third teeth around which the fourth stator winding 324 is wound are arranged in areas on opposite sides of the second boundary line L2.

[0095] In the figure, the numbers "first" to "fourth" written at the tips of the double-headed arrows perpendicular to the boundary lines L1 and L2 refer to the areas where the first to fourth stator windings 321 to 324 are arranged. This allows the wiring areas of the stator windings 321 to 324 to be divided into systems. This makes it possible to shorten the length of the crossover wires within each system.

[0096] This configuration is also common to the second to ninth embodiments. When expressed using the up-down, left-right directions as viewed from the plane of the drawing in which tooth T1 is arranged on the right side, the first boundary line L1 extends substantially in the left-right direction, dividing the multiple teeth T1 to T18 into upper and lower sections, except for the eighth embodiment. The upper side of the first boundary line L1 is the arrangement area for the first stator winding 321, and the lower side of the first boundary line L1 is the arrangement area for the third stator winding 323.

[0097] The second boundary line L2 extends substantially in the vertical direction and divides the plurality of teeth T1 to T18 into left and right. In embodiments other than the first and third embodiments, the left side of the second boundary line L2 is the arrangement area for the second stator winding 322, and the right side of the second boundary line L2 is the arrangement area for the fourth stator winding 324. On the other hand, in the first and third embodiments, the right side of the second boundary line L2 is the arrangement area for the second stator winding 322, and the left side of the second boundary line L2 is the arrangement area for the fourth stator winding 324.

[0098] Furthermore, by overlapping the layout area of ​​the stator windings 321-324 defined by the first boundary line L1 and the second boundary line L2 with the layout of the lead-out wires A1-A4, B1-B4, and C1-C4 of each system shown in FIG. 3 , the lengths of the lead-out wires A1-A4, B1-B4, and C1-C4 can be shortened. This reduces the total winding resistance of the motor 10, improving power efficiency. Here, it is assumed that the viewing direction of FIG. 3 is the same as that of FIG. 10 , etc. Regarding the left-right layout of the lead-out wires A2, B2, and C2 of the second system and the lead-out wires A4, B4, and C4 of the fourth system shown in FIG. 3 , a "2 left, 4 right" layout is preferred in all but the first and third embodiments, while a "4 left, 2 right" layout is preferred in the first and third embodiments.

[0099] Second Embodiment Fig. 11 shows a second embodiment in which a magnetomotive force phase difference of 40° occurs when current is supplied with a 20° phase difference. Fig. 7 shows, as an example of a "magnetomotive force phase difference of 40°," the sum of the magnetomotive forces of the W-phase partial winding W1- of the first stator winding 321 and the U-phase partial winding U2+ of the second stator winding 322 in the third coil body Uc formed by being wound around the teeth T9 of the second embodiment.

[0100] The phase of the combined U-phase current Us+ is 40°, and the current amplitude is 1.88 times the basic current amplitude I flowing through the partial windings W1- / U2+ of the first and second stator windings 321, 322. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the first coil body Wa formed by the partial winding W1- is 20°. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the second coil body Ub formed by the partial winding U2+ is also 20°.

[0101] (Third embodiment) Fig. 12 shows a third embodiment in which a magnetomotive force phase difference of 80° occurs when current is supplied with a 40° phase difference. Fig. 8 shows, as an example of "a magnetomotive force phase difference of 80°," the sum of the magnetomotive forces of the W-phase partial winding W3- of the third stator winding 323 and the V-phase partial winding V2- of the second stator winding 322 in the third coil body Uc formed by being wound around the teeth T14 of the third embodiment.

[0102] The phase of the combined U-phase current Us+ is 20°, and the current amplitude is 1.53 times the fundamental current amplitude I flowing through the partial windings W3- / V2- of the third and second stator windings 323, 322. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the first coil body Wa formed by the partial winding W3- is 40°. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the second coil body Vb formed by the partial winding V2- is also 40°.

[0103] (Fourth embodiment) Fig. 13 shows a fourth embodiment in which a magnetomotive force phase difference of 40° is achieved with energization with a 40° phase difference. Fig. 8 shows, as an example of a "magnetomotive force phase difference of 40°," the sum of the magnetomotive forces of the U-phase partial winding U3+ of the third stator winding 323 and the U-phase partial winding U4+ of the fourth stator winding 324 in the third coil body Uc formed by being wound around the teeth T14 of the fourth embodiment.

[0104] The phase of the combined U-phase current Us+ is 20°, and the current amplitude is 1.88 times the fundamental current amplitude I flowing through the partial windings U3+ / U4+ of the third and fourth stator windings 323, 324. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the first coil body Ua formed by the partial winding U3+ is 20°. The phase difference between the magnetomotive force of the third coil body Uc and the magnetomotive force of the second coil body Ub formed by the partial winding U4+ is also 20°.

[0105] Fifth Embodiment Fig. 14 shows a table of an example of the layout of partial windings of four stator winding systems 321 to 324 in a 22P18S motor. Fig. 15 shows, as the fifth embodiment, a diagram in which a magnetomotive force phase difference of 80° is achieved with energization at a phase difference of 20°.

[0106] (Sixth and Seventh Embodiments) Fig. 16 shows a table of examples of partial winding arrangements for the four-system stator windings 321 to 324 in a 16P18S motor. Fig. 17 shows a diagram of a sixth embodiment where the magnetomotive force phase difference is 80° with energization at a 20° phase difference. Fig. 18 shows a diagram of a seventh embodiment where the magnetomotive force phase difference is 40° with energization at a 20° phase difference. As described above, in the 16P18S and 20P18S configurations, when the magnetomotive force phase difference is 40°, the first teeth and third teeth, and the second teeth and third teeth, on which stator windings of the same phase of the same system are wound, are adjacent in the circumferential direction.

[0107] Eighth Embodiment Fig. 19 shows a table of an example of the layout of partial windings of four stator winding systems 321 to 324 in a 20P18S motor. Fig. 20 shows, as the eighth embodiment, a diagram in which a magnetomotive force phase difference of 80° is achieved with energization at a 20° phase difference.

[0108] Ninth Embodiment The 28P36S of the ninth embodiment has a configuration in which the number of magnetic poles is (18±4)×m (m is an integer equal to or greater than 1) and the number of slots is 18×m, which corresponds to "18-4" or "m=2" in the general form. FIG. 21 shows a diagram in which the magnetomotive force phase difference is 80° when energized with a 20° phase difference. In FIG. 21, the reference numerals for the 36 teeth are omitted. The ninth embodiment can achieve the same effects as the above embodiments and can also be applied to an eight-channel system.

[0109] Similarly, the configuration where the number of magnetic poles is (18±4)×m (m is an integer greater than or equal to 1) and the number of slots is 18×m, which corresponds to "18+4" and "m=2", is the 44P36S. Also, the configuration where the number of magnetic poles is (18±2)×n (n is an integer greater than or equal to 1) and the number of slots is 18×n, which corresponds to "n=2", is the 32P36S and 40P36S. Furthermore, it can also be expanded to cases where "m≧3" or "n≧3".

[0110] (Other embodiments) (a) In a motor having each "number of magnetic poles-number of slots," the arrangement of the partial windings of the stator winding 32 wound around each tooth is not limited to the above example. The windings may be arranged in the opposite direction to the above example, with tooth T1, where the current phase is at an electrical angle of 0°, as the reference point. The first stator winding 321 and the third stator winding 323 may be completely interchanged, and the second stator winding 322 and the fourth stator winding 324 may be completely interchanged.

[0111] (b) FIGS. 22 to 24 show examples of the arrangement of the lead wires A1 to A4, B1 to B4, and C1 to C4 of the stator windings 321 to 324, different from that shown in FIG. 3 . Similar to the arrangement example shown in FIG. 3 , in the first lead wire group ABC13, the lead wires A1, B1, and C1 are arranged symmetrically with the lead wires A3, B3, and C3, with respect to each phase, about the rotation axis 11. In the second lead wire group ABC24, the lead wires A2, B2, and C2 are arranged symmetrically with the lead wires A4, B4, and C4, with respect to each phase, about the rotation axis 11. As in FIG. 3 , the "2 left, 4 right" arrangement and the "4 left, 2 right" arrangement may be interchanged. This minimizes errors due to disturbance magnetic flux in the angle sensor 56, which detects the rotation angle of the rotor 40 based on changes in the magnetic field of the sensor magnet 12.

[0112] In the arrangement example shown in Figure 22, the center line M13 of the first leader group ABC13 and the center line M24 of the second leader group ABC24 are not perpendicular to each other, but intersect at an angle of less than 90° (approximately 75° in the example shown). The opposing distances d13 and d24 of the leader groups ABC13 and ABC24 are equal. In the arrangement example shown in Figure 23, the opposing distances d13 and d24 of the leader groups ABC13 and ABC24 are different from those in Figure 22. In other words, the first leader group ABC13 and the second leader group ABC24 are arranged on concentric circles with different diameters. In the arrangement example shown in Figure 24, the intersecting angle between the center lines M13 and M24 of the leader groups ABC13 and ABC24 is 0°. That is, the first group of leads ABC13 and the second group of leads ABC24 are arranged side by side within an area of ​​a predetermined width.

[0113] As described above, the present disclosure is not limited to the above-described embodiments, and can be embodied in various forms without departing from the spirit of the present disclosure.

[0114] (Disclosure of Technical Ideas) This specification discloses multiple technical ideas described in the following multiple clauses. Some clauses may be described in a multiple dependent form, with the subsequent clause alternatively referring to the preceding clause. Furthermore, some clauses may be described in a multiple dependent form, with the subsequent clause referring to another multiple dependent clause. These multiple dependent clauses define multiple technical ideas.

[0115] (Technical Idea 1) A rotor (40) having a plurality of magnetic poles (42) whose polarities alternate in the circumferential direction and which rotates integrally with a rotating shaft; and a stator (30) having a three-phase stator winding (32) and a stator core (31) having a plurality of teeth (T1 to T18) provided at predetermined intervals in the circumferential direction and around which the stator winding is wound, wherein the stator winding includes a first stator winding (321) to which three-phase current is supplied from a first inverter (51), a second stator winding (322) to which three-phase current is supplied from a second inverter (52), a third stator winding (323) to which three-phase current is supplied from a third inverter (53), and a fourth stator winding (324) to which three-phase current is supplied from a fourth inverter (54), the three-phase current supplied from the first inverter and the three-phase current supplied from the third inverter are conducted with the same current amplitude and phase, the three-phase current supplied from the second inverter and the three-phase current supplied from the fourth inverter are conducted with the same current amplitude and phase, the three-phase current supplied from the first inverter and the third inverter and the three-phase current supplied from the second inverter and the fourth inverter have a predetermined current phase difference, a U-phase first coil body (Ua) formed by winding the first stator winding or the third stator winding of the U-phase of the three phases around a first tooth, and a V-phase first coil body (Va) formed by winding the first stator winding or the third stator winding of the V-phase of the three phases around a first tooth, a W-phase first coil body (Wa) formed by winding the first stator winding or the third stator winding of the W-phase of the three phases around a first tooth; a U-phase second coil body (Ub) formed by winding the second stator winding or the fourth stator winding of the U-phase of the three phases around a second tooth; a V-phase second coil body (Vb) formed by winding the second stator winding or the fourth stator winding of the V-phase of the three phases around a second tooth; and a W-phase second coil body (Wb) formed by winding the second stator winding or the fourth stator winding of the W-phase of the three phases around a second tooth.a U-phase third coil body (Uc) formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth; a V-phase third coil body (Vc) formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth; and a W-phase third coil body (Wc) formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth, so that the phase difference between the magnetomotive force of the third coil body (Uc, Vc, Wc) of each phase relative to the magnetomotive force of the first coil body (Ua, Va, Wa) of each phase and the phase difference between the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase relative to the magnetomotive force of the third coil body (Uc, Vc, Wc) of each phase are within a predetermined phase range including 20 degrees in electrical angle, or so that the phase difference between the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase relative to the magnetomotive force of the first coil body (Ua, Va, Wa) of each phase and the phase difference between the magnetomotive force of the third coil body (Ub, Vb, Wb) of each phase are within a predetermined phase range including 20 degrees in electrical angle, A rotating electric machine in which a total phase difference is set between a magnetomotive force generated by a partial winding of the first stator winding or the third stator winding wound on the third tooth and a magnetomotive force generated by a partial winding of the second stator winding or the fourth stator winding wound on the third tooth, or a total phase difference is set between a current flowing through a partial winding of the first stator winding or the third stator winding wound on the third tooth and a current flowing through a partial winding of the second stator winding or the fourth stator winding wound on the third tooth (Technical Idea 2).The rotating electric machine according to Technical Idea 1, wherein a current phase difference between the three-phase currents supplied from the first inverter and the third inverter and the three-phase currents supplied from the second inverter and the fourth inverter is set within a range of 15 to 25 degrees, or within a range of 35 to 45 degrees. (Technical Idea 3) The rotating electric machine according to Technical Idea 1 or 2, wherein the total phase difference is set within a range of 72 to 88 degrees in electrical angle, and the number of magnetic poles of the rotor is (18±4)×m (m is an integer of 1 or greater) and the number of slots between the teeth is 18×m, or the number of magnetic poles of the rotor is (18±2)×n (n is an integer of 1 or greater) and the number of slots between the teeth is 18×n. (Technical Idea 4) When the number of turns of the first stator winding or the third stator winding wound around the first teeth and the number of turns of the second stator winding or the fourth stator winding wound around the second teeth are each defined as "Nab", and the number of turns of the first stator winding or the third stator winding wound around the third teeth and the number of turns of the second stator winding or the fourth stator winding wound around the third teeth are each defined as "Nc", a rotating electric machine according to Technical Idea 3, in which the number of turns of each is set to satisfy the relationship 1.4≦Nab / Nc≦1.6. (Technical Idea 5) A rotating electric machine according to Technical Idea 1 or 2, wherein the total phase difference is set in the range of 32 to 48 degrees in electrical angle, and the number of magnetic poles of the rotor is (18±4)×m (m is an integer of 1 or more) and the number of slots between the teeth is 18×m, or the number of magnetic poles of the rotor is (18±2)×n (n is an integer of 1 or more) and the number of slots between the teeth is 18×n. (Technical Idea 6) When the number of turns of the first stator winding or the third stator winding wound around the first teeth and the number of turns of the second stator winding or the fourth stator winding wound around the second teeth are respectively defined as "Nab", and the number of turns of the first stator winding or the third stator winding wound around the third teeth and the number of turns of the second stator winding or the fourth stator winding wound around the third teeth are respectively defined as "Nc", thenThe rotating electric machine according to Technical Idea 5, in which the number of turns of each is set to satisfy the relationship 1.8≦Nab / Nc≦2.0. (Technical Idea 7) The rotating electric machine according to any one of Technical Ideas 1 to 6, in which the first teeth and the third teeth around which the first stator winding of the same phase is wound are adjacent in the circumferential direction, the second teeth and the third teeth around which the second stator winding of the same phase is wound are adjacent in the circumferential direction, the first teeth and the third teeth around which the third stator winding of the same phase is wound are adjacent in the circumferential direction, and the second teeth and the third teeth around which the fourth stator winding of the same phase is wound are adjacent in the circumferential direction. (Technical Idea 8) A rotating electric machine described in any one of Technical Ideas 1 to 7, wherein, when projected in the direction of the rotation axis, all of the first teeth and third teeth around which the first stator winding of each phase is wound and all of the first teeth and third teeth around which the third stator winding of each phase is wound are arranged in areas on opposite sides of a first boundary line (L1) that is a straight line passing through the rotation axis, and all of the second teeth and third teeth around which the second stator winding of each phase is wound and all of the second teeth and third teeth around which the fourth stator winding of each phase is wound are arranged in areas on opposite sides of a second boundary line (L2) that is a straight line passing through the rotation axis. (Technical Idea 9) A rotating electric machine according to any one of Technical Ideas 1 to 8, wherein an angle sensor (56) is provided that detects the rotation angle of the rotor based on changes in the magnetic field of a sensor magnet (12) fixed to an end of the rotating shaft, wherein lead wires (A1, B1, C1) of the first stator winding connected to the first inverter and lead wires (A3, B3, C3) of the third stator winding connected to the third inverter are arranged so that each phase is symmetrical about the rotating shaft, and wherein lead wires (A2, B2, C2) of the second stator winding connected to the second inverter and lead wires (A4, B4, C4) of the fourth stator winding connected to the fourth inverter are arranged so that each phase is symmetrical about the rotating shaft.

[0116] The present disclosure has been described based on the embodiments. However, the present disclosure is not limited to the embodiments and structures. The present disclosure also encompasses various modifications and variations within the scope of equivalents. Furthermore, 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 rotor (40) having a plurality of magnetic poles (42) whose polarities alternate in the circumferential direction and which rotates integrally with a rotating shaft; and a stator (30) having a three-phase stator winding (32) and a stator core (31) having a plurality of teeth (T1 to T18) arranged at predetermined intervals in the circumferential direction and around which the stator winding is wound, wherein the stator winding includes a first stator winding (321) to which a three-phase current is supplied from a first inverter (51), a second stator winding (322) to which a three-phase current is supplied from a second inverter (52), a third stator winding (323) to which a three-phase current is supplied from a third inverter (53), and a fourth stator winding (324) to which a three-phase current is supplied from a fourth inverter (54), a three-phase current supplied from the first inverter and a three-phase current supplied from the third inverter are energized with the same current amplitude and phase, a three-phase current supplied from the second inverter and a three-phase current supplied from the fourth inverter are energized with the same current amplitude and phase, a three-phase current supplied from the first inverter and the third inverter and a three-phase current supplied from the second inverter and the fourth inverter have a predetermined current phase difference, respectively, a U-phase first coil body (Ua) formed by winding the first stator winding or the third stator winding of a U-phase of the three phases around a first tooth, a V-phase first coil body (Va) formed by winding the first stator winding or the third stator winding of a V-phase of the three phases around a first tooth, a first coil body (Wa) of W phase formed by winding the first stator winding or the third stator winding of W phase of the three phases around a first tooth; a second coil body (Ub) of U phase formed by winding the second stator winding or the fourth stator winding of U phase of the three phases around a second tooth; a second coil body (Vb) of V phase formed by winding the second stator winding or the fourth stator winding of V phase of the three phases around a second tooth; and a second coil body (Wb) of W phase formed by winding the second stator winding or the fourth stator winding of W phase of the three phases around a second tooth.the third coil body (Uc) of a U phase formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth; a third coil body (Vc) of a V phase formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth; and a third coil body (Wc) of a W phase formed by winding the first stator winding or the third stator winding of any one of the three phases, and the second stator winding or the fourth stator winding of any one of the three phases, around a third tooth, a phase difference between the magnetomotive force of the third coil body (Uc, Vc, Wc) of each phase and the magnetomotive force of the first coil body (Ua, Va, Wa) of each phase, and a phase difference between the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase and the magnetomotive force of the third coil body (Uc, Vc, Wc) of each phase, are within a predetermined phase range including 20 degrees in electrical angle, or a phase difference between the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase and the magnetomotive force of the first coil body (Ua, Va, Wa) of each phase, and a phase difference between the magnetomotive force of the third coil body (Ub, Vb, Wb) of each phase and the magnetomotive force of the second coil body (Ub, Vb, Wb) of each phase, are within a predetermined phase range including 20 degrees in electrical angle, A rotating electric machine in which a combined phase difference is set between a magnetomotive force generated by a partial winding of the first stator winding or the third stator winding wound around the third tooth and a magnetomotive force generated by a partial winding of the second stator winding or the fourth stator winding wound around the third tooth, or a combined phase difference is set between a current flowing through a partial winding of the first stator winding or the third stator winding wound around the third tooth and a current flowing through a partial winding of the second stator winding or the fourth stator winding wound around the third tooth.

2. A rotating electric machine as described in claim 1, wherein the current phase difference between the three-phase currents supplied from the first inverter and the third inverter and the three-phase currents supplied from the second inverter and the fourth inverter is set within a range of 15 to 25 degrees, or within a range of 35 to 45 degrees.

3. A rotating electric machine as described in claim 1, wherein the combined phase difference is set in the range of 72 to 88 degrees in electrical angle, the number of magnetic poles of the rotor is (18±4)×m (m is an integer greater than or equal to 1) and the number of slots between the teeth is 18×m, or the number of magnetic poles of the rotor is (18±2)×n (n is an integer greater than or equal to 1) and the number of slots between the teeth is 18×n.

4. A rotating electric machine as set forth in claim 3, wherein the number of turns of the first stator winding or the third stator winding wound around the first teeth and the number of turns of the second stator winding or the fourth stator winding wound around the second teeth are respectively defined as "Nab", and the number of turns of the first stator winding or the third stator winding wound around the third teeth and the number of turns of the second stator winding or the fourth stator winding wound around the third teeth are respectively defined as "Nc", wherein the number of turns of each is set to satisfy the relationship 1.4≦Nab / Nc≦1.

6.

5. A rotating electric machine as described in claim 1, wherein the combined phase difference is set in the range of 32 to 48 degrees in electrical angle, the number of magnetic poles of the rotor is (18±4)×m (m is an integer greater than or equal to 1) and the number of slots between the teeth is 18×m, or the number of magnetic poles of the rotor is (18±2)×n (n is an integer greater than or equal to 1) and the number of slots between the teeth is 18×n.

6. A rotating electric machine as set forth in claim 5, wherein the number of turns of the first stator winding or the third stator winding wound around the first teeth and the number of turns of the second stator winding or the fourth stator winding wound around the second teeth are respectively defined as "Nab", and the number of turns of the first stator winding or the third stator winding wound around the third teeth and the number of turns of the second stator winding or the fourth stator winding wound around the third teeth are respectively defined as "Nc", wherein the number of turns of each is set to satisfy the relationship 1.8≦Nab / Nc≦2.

0.

7. A rotating electric machine as described in claim 1, wherein the first teeth and third teeth around which the first stator winding of the same phase is wound are adjacent in the circumferential direction, the second teeth and third teeth around which the second stator winding of the same phase is wound are adjacent in the circumferential direction, the first teeth and third teeth around which the third stator winding of the same phase is wound are adjacent in the circumferential direction, and the second teeth and third teeth around which the fourth stator winding of the same phase is wound are adjacent in the circumferential direction.

8. A rotating electric machine as described in claim 1, wherein, when projected in the direction of the rotation axis, all of the first teeth and third teeth around which the first stator winding of each phase is wound and all of the first teeth and third teeth around which the third stator winding of each phase is wound are arranged in areas opposite each other with a first boundary line (L1) being a straight line passing through the rotation axis, and all of the second teeth and third teeth around which the second stator winding of each phase is wound and all of the second teeth and third teeth around which the fourth stator winding of each phase is wound are arranged in areas opposite each other with a second boundary line (L2) being a straight line passing through the rotation axis.

9. A rotating electric machine as claimed in any one of claims 1 to 8, further comprising an angle sensor (56) for detecting the rotation angle of the rotor based on changes in the magnetic field of a sensor magnet (12) fixed to the end of the rotating shaft, wherein a lead-out wire (A1, B1, C1) of the first stator winding connected to the first inverter and a lead-out wire (A3, B3, C3) of the third stator winding connected to the third inverter are arranged so that each phase is symmetrical about the rotating shaft, and wherein a lead-out wire (A2, B2, C2) of the second stator winding connected to the second inverter and a lead-out wire (A4, B4, C4) of the fourth stator winding connected to the fourth inverter are arranged so that each phase is symmetrical about the rotating shaft.

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