Rotating electric machine

Abstract

Rotating electric machine (1) with a central longitudinal axis (1C), comprising: a stator (100) comprising armature coils (104) wound around the stator (100) with concentrated winding, the armature coils (104) being configured to generate magnetic flux when excited; and a rotor (300) which is rotatable about the central longitudinal axis (1C) in response to the flow of the magnetic flux, wherein the rotor (300) comprises a plurality of salient poles (302) which are wound by rotor windings (330) which are capable of inducing at least one induced current when the magnetic flux couples with the rotor (300), wherein the rotor (300) comprises at least one rectifier circuit (C1 to C6), wherein the rotor windings (330) are wound such that the salient poles (302) can operate as electromagnets whose magnetization directions are alternately reversed along an arc length of a circle around the central longitudinal axis (1C), wherein each rectifier circuit forms a closed circuit consisting of a group of rotor windings (330), wherein in each group some of the rotor windings (330), whose current phases of the induced current are the same, are connected in series with a rectifier element (D1 to D8), wherein the rotor windings (330) are either divided into four groups such that in each group all rotor windings (330) are connected in series with a rectifier element to form a rectifier circuit or the rotor windings (330) are divided into two groups such that each group comprises several series circuits, of which a first and a second series circuit are connected in parallel and each of these first and second series circuits is connected in series with a rectifying element.

Description

[Technical field]

[0001] The present invention relates to rotating electrical machines having windings around a rotor. [General state of the art]

[0002] Rotating electric machines are installed as power sources in various devices. In applications such as vehicles, a rotating electric machine is either installed independently to serve as a power source for an electric car, or it is installed together with an internal combustion engine to serve as a power source for a hybrid electric car.

[0003] In the case of a hybrid electric car, a rotating electric machine can be integrated into a system combined with an internal combustion engine via a planetary gear set, to function as both a generator and a motor as needed. This requires the integration of an internal combustion engine, a rotating electric machine for power generation, and a rotating electric machine for propulsion within the system, along with a planetary gear set, which increases the system's size and makes it difficult to install in small cars.

[0004] JP 2013 - 188 065 A discloses a known rotating electrical machine combined to function as a generator, a motor and a planetary gear set.

[0005] In Fig. Figure 9 is the well-known rotating electric machine described in JP 2013-188065A, generally designated as 400. The rotating electric machine 400 comprises a stator S with armature windings C having six pole pairs (number of pole pairs A), a first rotor R1 with permanent magnets PM having ten pole pairs (number of pole pairs P), and a second rotor R2 with magnetic tracks MP having 16 poles (number of poles H = A + P). This well-known rotating electric machine 400 utilizes the principle of magnetic modulation and operates as a so-called "magnetic modulation double-shaft motor" by causing the stator S, the first rotor R1, and the second rotor R2 to function as elements of a planetary gear set, i.e., as a sun gear, a planet carrier, and a ring gear.

[0006] JP 2010-279 165 A discloses a rotating electric machine with salient poles around which rotor windings are wound. The rotor windings are electrically connected to each other in such a way that they function as opposite poles. Diodes are provided for current rectification for the rotor windings assigned to the opposite poles.

[0007] DE 10 2014 003 658 A1 discloses a reluctance motor with a stator comprising armature coils wound around the stator with concentrated winding, the armature coils being configured to generate magnetic flux when excited. A rotor comprises a plurality of salient poles wound by rotor windings capable of inducing at least one induced current when the magnetic flux couples with the rotor. The rotor includes at least one rectifier circuit, the rotor windings being wound such that the salient poles can operate as electromagnets whose magnetization directions are alternately reversed along an arc length of a circle around the central longitudinal axis. The rectifier circuit is a closed circuit in which some of the rotor windings, whose current phases of the induced current are the same, are connected in series to a rectifier element.

[0008] CN 1 01 951 090 B discloses a rotating electric machine with a second rotor which is in a magnetic path for the magnetic flux flowing through the first-mentioned rotor, wherein the second rotor comprises a plurality of elements made of soft magnetic material spaced apart from each other along an arc length of a circle around the central longitudinal axis. [Brief description of the invention][Technical problem]

[0009] However, with the well-known rotating electric machine 400, described in JP 2013 - 188 065 A, it is difficult to generate a large power output by increasing the torque density, as with an internal permanent magnet (IPM) motor, in which the magnetic force of the permanent magnets can already be used as a magnetic torque, and this requires the use of expensive permanent magnets with a high magnetic flux density to compensate for the lack of torque.

[0010] Furthermore, the configuration of the rotating electric machine 400 requires an expensive permanent magnet that has a large coercive force and small demagnetization due to heat, with such rare and expensive earth elements as dysprosium (Dy) and terbium (Tb) being added, such as a neodymium magnet (Nd-Fe-B magnet), because the variations in the magnetic flux coupled to the permanent magnet are large.

[0011] With regard to this problem, the inventor of the present application has proposed a rotating electric machine in which magnetic forces generated by electromagnets are produced by converting the variations of an asynchronous magnetic flux (i.e. variations of the magnetic flux from a difference frequency between the rotating stator magnetic field and the rotor speed).

[0012] This rotating electric machine has rotor windings around a rotor. The rotor windings are arranged to convert the asynchronous magnetic flux coupled to the rotor into induced electromotive force, provided the rotor rotates synchronously with the rotating stator magnetic field. The induced electromotive force is rectified by a diode in a rectifier circuit mounted on the rotor. The rectified current flows through the rotor windings to excite them, causing them to act as electromagnets capable of generating magnetic force.

[0013] However, a torque ripple is generated and / or the efficient use of the induced electromotive force as excitation current is not satisfactorily high, depending on the configuration of a rectifier circuit, where the induced electromotive force, into which an asynchronous magnetic flux coupled with a rotor is converted, is converted into excitation current.

[0014] Therefore, it is an object of the present invention to provide a rotating electric machine that is capable of smoothing out torque ripple. [Solution to the problem]

[0015] According to one aspect, a rotating electrical machine with a central longitudinal axis is provided, comprising: a stator comprising armature coils wound around the stator with concentrated winding, the armature coils being configured to generate magnetic flux when excited; and a rotor rotatable about the central longitudinal axis in response to the flow of magnetic flux, the rotor comprising a plurality of salient poles wound by rotor windings capable of inducing at least one induced current when the magnetic flux couples with the rotor, the rotor comprising at least one rectifier circuit, the rotor windings being wound such that the salient poles operate as electromagnets whose magnetization directions are alternately reversed one after the other along an arc length of a circle around the central longitudinal axis.wherein each rectifier circuit forms a closed circuit consisting of a group of rotor windings, wherein in each group some of the rotor windings whose current phases of the induced current are the same are connected in series to a rectifier element, wherein the rotor windings are either divided into four groups such that in each group all rotor windings are connected in series to a rectifier element to form a rectifier circuit, or the rotor windings are divided into two groups such that each group comprises several series circuits, of which a first and a second series circuit are connected in parallel, and these first and second series circuits are each connected in series to a rectifier element. [Advantageous effects of the invention].

[0016] In this way, an embodiment of the present invention is able to smooth out the torque ripple. [Brief description of the drawings] Fig. Figure 1 is a cross-section of one half (1 / 2) of a first embodiment of a rotating electric machine according to the present invention. Fig. 2 is an axial cross-section of the rotating electric machine located in Fig. 1 is shown. Fig. Figure 3 is a graphical representation of a harmonic analysis of the magnetic flux density around a gap between an inner rotor and an outer rotor of the rotating electric machine. Fig. Figure 4 is a simplified cross-section of the inner rotor of the rotating electric machine. Fig. Figure 5 shows rectifier circuits, each of which is a closed circuit including a diode on the inner rotor. Fig. Figure 6 is a cross-section of one half (1 / 2) of a second embodiment of a rotating electric machine according to the present invention. Fig. Figure 7 shows rectifier circuits, each of which is a closed circuit with two diodes connected to an inner rotor of the Fig. The rotating electric machine shown in section 6 is included. Fig. Figure 8 is a simulation result showing magnetic circuits of the magnetic flux associated with the inner rotor of the Fig. 6 shown rotating electric machine couples. Fig. Figure 9 is a cross-section of the previously mentioned rotating electric machine in the form of a magnetic modulation double-shaft motor according to the state of the art. [Description of the embodiments]

[0017] With reference to the attached drawings, embodiments of a rotating electric machine are described below. (First embodiment)

[0018] Referring to the Fig. 1 and Fig. 2 is a rotating electric machine 1 configured as a double-rotor type, having a central longitudinal axis 1C. The rotating electric machine 1 comprises a stator 100, which is approximately cylindrical, an outer or second rotor 200, which is arranged radially inside the stator 100 relative to the central longitudinal axis 1C, and an inner or first rotor 300, which is arranged radially from the outer rotor 200 relative to the central longitudinal axis 1C. The outer rotor 200 and the inner rotor 300 are mounted such that the outer and inner rotors 200 and 300 are relatively rotatable about the central longitudinal axis 1C. Fig. Figure 1 shows a radial half (1 / 2) of a cross-sectional view of the rotating electric machine, i.e., a radial displacement of 180° of a mechanical angle of 360°. The inner rotor 300 forms a rotor according to the claims.

[0019] The stator 100 comprises a stator core 101. The stator core 101 includes a stator base and a plurality of stator teeth 102. The stator teeth 102 extend radially (relative to the central longitudinal axis 1C) inwards from the stator base. As shown from Fig. As can be seen in Figure 1, the stator teeth 101 are arranged radially around the central longitudinal axis 1C such that the stator teeth 102 are spaced apart from each other along an arc length around a circle around the central longitudinal axis 1C. The stator teeth 102 extend to inner ends or inner circumferential surfaces 102a such that the inner circumferential surfaces 102a and the outer circumferential surfaces 201a of a magnetic path component 201 of the outer rotor 200, which will be described later, are opposite each other across an air gap G1.

[0020] The stator 100 contains armature coils 104, which can be divided into W-phase coils, V-phase coils, and U-phase coils for a three-phase alternating current. The armature coils 104 are inserted into slots 103, each of which is defined between two opposing sides 102b of two adjacent stator teeth 102. The armature coils 104 are wound around the stator teeth 102 with concentrated winding. The armature coils 104 generate magnetic flux when energized.

[0021] In the stator 100, the supply of three-phase alternating current to these armature coils 104 causes the generation of a rotating magnetic field. The generated rotating magnetic field penetrates the outer rotor 200 and the inner rotor 300, causing them to rotate relative to the stator 100.

[0022] The outer rotor 200 comprises a magnetic path component 201 and a variety of non-magnetic elements 202. The magnetic path component 201 is made of a soft magnetic material with high permeability, such as steel. Each of the non-magnetic elements 201 is made of a non-magnetic material that does not allow the flow of magnetic flux, such as polyphenylene sulfide (PPS) resin or the like. The magnetic path component 201 extends along the central longitudinal axis 1C. Each of the non-magnetic elements 202 extends along the central longitudinal axis 1C. It should be noted that the central longitudinal axis is an axis of rotation about which the outer and inner rotors 200 and 300 rotate relative to the stator 100.

[0023] Referring to Fig. 2 the magnetic path component 201 and the non-magnetic elements 202 are connected to and concentrically mounted by a disk-shaped part with a large diameter 205, which is arranged at one axial end side of the outer rotor 200, and by a cylindrical shaft 206, which is arranged at the other axial end side of the outer rotor 200.

[0024] The magnetic path component 201 comprises a plurality of pole shoe segments 201A and a plurality of bridge segments 201B. The pole shoe segments 201A are arranged radially around the central longitudinal axis 1C such that they are spaced apart from one another along an arc length of a circle around the central longitudinal axis 1C. Each of the non-magnetic elements 202 is positioned between two adjacent pole shoe segments 201A such that each pole shoe segment 201A faces the adjacent non-magnetic element 201. Each of the bridge segments 201B is positioned between two adjacent pole shoe segments 201A and connects them at radially outer (relative to the central longitudinal axis 1C) and inner positions of the non-magnetic element 202 positioned between the two pole shoe segments 201A.

[0025] The pole shoe segments 201A and the bridge segments 201B are formed in one piece such that the magnetic path component 201 is formed as a one-piece core, of which the pole shoe segments 201A and the bridge segments 201B are one-piece parts. The magnetic path component 201 is formed as the one-piece core by laminating a plurality of electromagnetic steel plates one after the other along the central longitudinal axis 1C.

[0026] Each of the non-magnetic elements 202 is in a space that is defined and surrounded by the two adjacent pole shoe segments 201A and one of the bridge segments 201B. In the illustrated outer rotor 200, the pole shoe segments 201A are made of soft magnetic material and the non-magnetic elements 202 are arranged radially around the central longitudinal axis 1C, such that the pole shoe segments 201A are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C and such that each of the non-magnetic elements 202 is located between two adjacent pole shoe segments 201A.

[0027] The outer rotor 200 is arranged such that an outer circumferential surface 201a of the magnetic path component 201 is opposite the inner circumferential surfaces (inner ends) 102a of the stator teeth of the stator 100 and that an outer circumferential surface 201b of the magnetic path component 201 is opposite the outer circumferential surfaces (outer ends) 302a of the rotor teeth 302 of an inner rotor 300 described later.

[0028] The armature coils 104 of the stator 100 generate a magnetic flux that enters the outer rotor 200. The magnetic flux entering the outer rotor 200 flows efficiently through the pole shoe segments 201A, but the non-magnetic elements 202 prevent the flow of the magnetic flux. After passing through the pole shoe segments 201A, the magnetic flux enters the rotor teeth 302 of the inner rotor 300 from the outer circumferential surfaces 302a and, on its return to the stator 100, flows once again through the pole shoe segments 201A to complete a magnetic circuit.

[0029] By rotating the outer rotor 200 in this way, it is possible to change the number of poles and the frequency of the rotating magnetic field generated by the armature coils 104. A torque is generated during the synchronous rotation of the modulated rotating magnetic field and the inner rotor 300.

[0030] The inner rotor 300 comprises a rotor core 301, which is formed by laminating electromagnetic steel plates along the central longitudinal axis 1C. The rotor core 301 includes a rotor base and a plurality of rotor teeth (salient poles) 302. The rotor teeth 302 extend radially (relative to the central longitudinal axis 1C) outwards from the rotor base. As shown in the figure Fig. As can be seen in Figure 1, the rotor teeth 302 are arranged radially around the central longitudinal axis 1C, such that the rotor teeth 302 are spaced apart from each other along an arc length of a circle around the central longitudinal axis 1C. The rotor teeth 302 extend to outer ends or outer circumferential surfaces 302a of the rotor teeth 302, such that the outer circumferential surfaces 302a are opposite an inner circumferential surface 201b of the magnetic path component 201 of the outer rotor 200 across an air gap G2.

[0031] The rotor windings 330 are wound around the rotor teeth 302, with spaces, each of which is between sides 302b of the two adjacent rotor teeth 302, being used as slots.

[0032] The rotor windings 330 are each wound with concentrated winding around the rotor teeth 330, such that the rotor windings 330 are wound around the two circumferentially adjacent rotor teeth 302 in opposite winding directions. The rotor windings 330 are arranged radially around the central longitudinal axis 1C such that the rotor windings 330 are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C. The rotor teeth 302 are designed to function as electromagnets by causing the rotor windings 330 to generate (or induce) induced currents during the coupling of the magnetic flux with the rotor windings 330 to supply the induced currents as excitation currents.

[0033] The rotor windings 330 are wired in such a way that the two adjacent rotor teeth 302 are polarized differently.

[0034] In Fig. Figure 1 shows only half of the inner rotor 300. Therefore, only eight (8) rotor windings 330 are shown. These eight rotor windings 330 are called 330-1, 330-2, 330-3, 330-4, 330-5, 330-6, 330-7, and 330-8 in that order along the direction of rotation of the inner rotor 300, i.e., in a counterclockwise direction, to avoid confusion.

[0035] In the rotating electric machine 1, the magnetic force from the stator 100 is modulated by the outer rotor 200, and the inner rotor 300 is driven by a torque generated by the synchronous rotation of the inner rotor with the modulated magnetic flux. In addition to the synchronous modulated magnetic flux, an asynchronous magnetic flux couples with the inner rotor 300.

[0036] Fig. Figure 3 shows a harmonic analysis result of the harmonic components contained in the flux density around a gap between the inner rotor 300 and the outer rotor 200, the so-called "gap flux density". The pole configuration is such that the stator 100 has 4 pole pairs, the outer rotor 200 has 12 poles, and the inner rotor 300 has 8 pole pairs. The inner rotor 300 is a solid rotor, i.e., a rotor without pulsation of magnetic resistance.

[0037] It's out Fig. It is evident from Figure 3 that an 8th-order or lower-order gap flux and a 16th-order or higher-order gap flux persist after the outer rotor 200 has modulated a 4th-order flux from the stator 100. Furthermore, it is evident that a 4th-order gap flux also persists due to the DC superposition term caused by a permanence dependent on the outer rotor 200. Fig. Figure 3 shows a simple dashed-dotted circle, labelled with the reference symbol L, representing the flux density of the 8th order slit flux, and another simple dashed-dotted circle, labelled with the reference symbol M, representing the flux density of the 4th order slit flux.

[0038] The order of the spatial harmonic of the synchronous flux, which is not modulated, becomes the pole pair of the stator. In the illustrated example of harmonic analysis, the magnetic flux of the 4th order spatial harmonic couples with the inner rotor 300 (assuming that a mechanical angle of 360° corresponds to the 1st order).

[0039] Fig. Figure 4 is a cross-section of the inner rotor 360, showing the arrangement of the rotor windings 330. Sixteen (16) rotor windings 330 are shown. These sixteen rotor windings 330 are called 330-1, 330-2, 330-3, 330-4, 330-5, 330-6, 330-7, 330-8, 330-9, 330-10, 330-11, 330-12, 330-13, 330-14, 330-15, and 330-16 in that order along one direction of rotation of the inner rotor, i.e., a counterclockwise direction, to avoid confusion.

[0040] The phases of the induced currents, which are induced due to the magnetic flux of the fourth spatial harmonic, which couples with the inner rotor 300 of the stator 100, are the same at 90° intervals.

[0041] The rotor windings 330 are divisible into and comprise four groups of rotor windings 330, such that the rotor windings 330 of each group generate induced currents that, in response to an injection of asynchronous magnetic flux to the inner rotor 300, have the same phase, although the rotor windings 330 of the different groups generate induced currents that have different phases. In the illustrated embodiment, the rotor windings 330 of each group are connected in series, and the induced currents are rectified by a rectifier element, for example, in the form of a diode.

[0042] Referring to Fig. 5 are the rotor windings 330-1, 330-5, 330-9 and 330-13, which generate induction currents with the same phase, and a diode D1 connected in series to form a rectifier circuit C1, which is a closed circuit.

[0043] Likewise, the rotor windings 330-2, 330-6, 330-10 and 330-14 and a diode D2 are connected in series to form a rectifier circuit C2, which is a closed circuit.

[0044] The rotor windings 330-3, 330.7, 330-11 and 330-15 and a diode D3 are connected in series to form a rectifier circuit C3, which is a closed circuit.

[0045] The rotor windings 330-4, 330-8, 330-12 and 330-16 and a diode D4 are connected in series to form a rectifier circuit C4, which is a closed circuit.

[0046] Obviously, the diodes D1, D2, D3 and D4 form rectifier elements according to the claims.

[0047] This configuration smooths out the torque ripple that results from variations in the induced current because the rectifier circuits C1, C2, C3 and C4 have different ripple currents or current ripples.

[0048] Furthermore, this configuration causes an increase in the excitation current by reducing a voltage drop caused by the diodes, because the number of diodes can be reduced compared to the case where 330 closed circuits are formed for the respective rotor windings, each comprising a diode.

[0049] Additionally, reducing the number of diodes allows for a miniaturization and weight reduction of the rotating electrical machine 1.

[0050] The principle of torque generation in the rotating electric machine 1 is now described. Among the magnetic flux components that come out of the stator 100, flow through the outer rotor 200 to couple with the inner rotor 300, at least one component, modulated by the rotation of the outer rotor 200, is synchronized with the rotation of the inner rotor 300 and couples with the inner rotor 300.

[0051] On the other hand, the magnetic flux coupled to a portion of the rotor windings 330 of the inner rotor 300 contains at least one component that varies without being modulated by the rotation of the outer rotor 200 (i.e., without being synchronized with the rotation of the inner rotor 300). This component causes that portion of the rotor windings 330 to generate an induced alternating current. The induced alternating current is rectified by the diodes to provide excitation current to energize the remaining portion of the rotor windings 330, causing the rotor teeth 302 to act as electromagnets to generate excitation magnetic flux. This results in the production of torque within the rotating electric machine 1.

[0052] It is pointed out that the supply of current from an alternating current source to the armature coils 104, which are wound with concentrated winding, causes the generation of magnetic flux, which comes out of the stator teeth 102 of the stator 100, flows through the pole shoe segments 201A of the outer rotor 200 and couples with the rotor teeth 302 of the inner rotor 300.

[0053] Then the armature coils 104 can be wound with distributed winding, although in the present embodiment they are wound with concentrated winding.

[0054] The rotating electric machine 1 is configured to enable the rotation of the inner rotor 300 relative to the stator 100 by an electromagnetic moment (a torque) without providing permanent magnets. In this inner rotor 300, the rotor teeth 302 are allowed to function as electromagnets whose magnetization directions (N-pole or S-pole) are alternately reversed along the arc length of the circle around the central longitudinal axis 1C, thereby enabling a smooth transition of magnetic flux that couples the inner rotor 300 and the outer rotor 200 around the slots 303.

[0055] This rotating electric machine 1 is capable of allowing the outer rotor 200 to rotate at low speeds and the inner rotor 300 to rotate at high speeds because the outer rotor 200 is rotatable relative to the stator 100 and because the inner rotor 300, to which the magnetic flux is coupled by the magnetic flux flowing through the rotating outer rotor 200 (i.e., through the magnetic components 201), is caused to rotate relative to the outer rotor 200 by the electromagnetic torque. Furthermore, the rotating electric machine 1 is capable of allowing the outer rotor 200 to rotate at high speeds and the inner rotor 300 to rotate at low speeds.

[0056] Furthermore, this rotating electric machine 1 is configured, depending on a relationship between the construction of the stator 100, the outer rotor 200, and the inner rotor 300, to generate a torque required for the rotation described above. If “A” is the number of pole pairs of the armature coils 104 of the stator 100, if “H” is the number of pole shoe segments 201A, which constitute the number of poles of the outer rotor 200, and if “P” is the number of pole pairs of the rotor teeth (electromagnets) 302, i.e., the number of pole pairs of the inner rotor 300, then the aforementioned relationship can be expressed, in particular, by the following equation (1). H=|A±P|

[0057] If this relationship is satisfied, torque is efficiently generated to enable efficient relative rotation between the outer rotor 200 and the inner rotor 300 relative to the stator 100. For example, the rotating electric machine 1 according to the present embodiment satisfies equation (1) because A (the number of pole pairs of the armature coils 104 on the stator 100) = 4, H (the number of pole pairs of the outer rotor 200) = 12, and P (the number of pole pairs of the rotor teeth 302 on the inner rotor 300) = 8.

[0058] Now, referring to Fig. In the rotating electric machine 1, the outer rotor 200 is surrounded by the stator 100. Furthermore, the outer rotor 200 surrounds the inner rotor 300. The outer rotor 200 and the inner rotor 300 are rotatable about the central longitudinal axis 1C of the rotating electric machine 1.

[0059] An outer shaft 210, rotatable about the central longitudinal axis 1C, is integrally connected to the outer rotor 200. An inner shaft 300, rotatable about the central longitudinal axis 1C, is integrally connected to the inner rotor 300. This allows the rotating electric machine 1 to be configured as a dual-axis flux-modulated rotor, capable of transmitting power to both the outer shaft 210 and the inner shaft 310 by utilizing the flux modulation principle.

[0060] Therefore, the rotating electric machine 1 can be manufactured to perform the same function as a known planetary gear set, such that the stator 100 acts as a sun gear of the planetary gear set, the outer rotor 200 as a planet carrier of the planetary gear set, and the inner rotor 300 as a ring gear of the planetary gear set. In the illustrated rotating electric machine 1, the outer rotor 200 is manufactured to function as a planet carrier.

[0061] This enables the rotating electric machine 1 to function not only as a power transmission mechanism but also as a drive source when the rotating electric machine 1 is mounted on a hybrid electric vehicle together with a motor (i.e., an internal combustion engine) to form a drive source in which the outer shaft 210 of the outer rotor 200 and the inner shaft 310 of the inner rotor 300 are directly connected as parts of a power transmission path of the vehicle, and by connecting a battery of the vehicle to the armature coils 104 of the stator 100 via an inverter.

[0062] As described, the rotor windings 330 are each wound with concentrated winding around the rotor teeth 330, such that the rotor windings 330 are wound around the two circumferentially adjacent rotor teeth 302 in opposite winding directions. Furthermore, the rotor windings 330 are arranged radially around the central longitudinal axis 1C, such that the rotor windings 330 are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C. The rotor windings 330 can be divided into and comprise four groups of rotor windings 330, such that the rotor windings 330 of each group generate induced currents of the same phase in response to the injection of an asynchronous magnetic flux to the rotor 300, although the rotor windings 330 of the different groups generate induced currents of different phases.In the illustrated embodiment, the rotor windings 330 of each group are connected in series, and the induced currents are rectified by rectifier elements, for example, in the form of a diode. The rotating electrical machine 1 according to the first embodiment comprises rotor windings 330 as described above and rectifier circuits C1, C2, C3, and C4 as described above.

[0063] This smooths out the torque ripple that arises from variations in the induced currents, because the rectifier circuits C1, C2, C3 and C4 have different ripple currents. (Second embodiment)

[0064] The second embodiment is described next. It should be noted that the same reference numerals used in the first embodiment are used to designate the elements or parts of the second embodiment.

[0065] Referring to Fig. 6. Each rotor tooth 302 has a set of rotor windings 330. The rotor windings 330 of each set serve as an induction coil I and an excitation coil F. The induction coil I and the excitation coil F are wound around each of the rotor teeth 302 by using slots as grooves 303, each of which is defined between opposite sides 302b of the adjacent rotor teeth 302, such that the induction coil I is arranged radially inward from and close to the outer end 302a of the rotor tooth 302, and the excitation coil F is arranged radially inward from the outer end 302a of the rotor tooth 302 and further recessed than the induction coil I. In other words, the induction coils I are on the side close to the outer rotor 200, while the excitation coils F are on the side close to the central longitudinal axis 1C.Furthermore, the induction coils I and the excitation coils F are inserted into the slots 303 and wound around the inner rotor 300 such that the induction coils I are arranged radially outwards (relative to the central longitudinal axis 1C) and the excitation coils F are arranged radially inwards. Each set of rotor windings 330, which serves as an induction coil I and as an excitation coil F, forms a coil according to the claims.

[0066] The induction coils I are wound with concentrated winding around the rotor teeth 302, such that the two adjacent induction coils I are wound in opposite directions to each other. The induction coils I are arranged radially around the central longitudinal axis 1C, such that the induction coils I are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C. Each of the induction coils I generates (or induces) an induced current when the flux density of the magnetic flux coupled to it changes.

[0067] The excitation coils F are each wound with concentrated winding around the rotor teeth 302, such that the two adjacent excitation coils F are wound in opposite directions. The excitation coils F are arranged radially around the central longitudinal axis 1C such that the excitation coils F are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C. Each of the excitation coils F acts as an electromagnet when it is energized by the application of the excitation current.

[0068] As described, the induction coil I and the excitation coil F are wound around each of the rotor teeth 302 such that the direction of the current flowing through the induction coil I coincides with the direction of the current flowing through the excitation coil F.

[0069] In Fig. Figure 6 shows only half of the inner rotor 300. Therefore, only eight (8) induction coils I and only eight (8) excitation coils F are shown. The eight induction coils I are named I1, I2, I3, I4, I5, I6, I7, and I8 in that order along one direction of rotation of the inner rotor 300, i.e., a counterclockwise direction, to avoid confusion. The eight excitation coils F are named F1, F2, F3, F4, F5, F6, F7, and F8 in that order along the direction of rotation of the inner rotor 300 to avoid confusion. As can be seen from the foregoing description, the inner rotor 300 carries 16 (16) induction coils I and 16 (16) excitation coils F. The remaining eight induction coils I, which are shown in Fig. The 6 not shown can be named I9, I10, I11, I12, I13, I14, I15 and I16 in that order along the direction of rotation of the inner rotor 300. The remaining eight excitation coils I, which are not shown in Fig. Figure 6 shows F9, F10, F11, F12, F13, F14, F15 and F16, which can be named in this order along the direction of rotation of the inner rotor 300.

[0070] The sixteen (16) induction coils I on the inner rotor 300 are divisible into an odd group, such as I1, I3, I5, I7, I9, I11, I13, and I15, and an even group, such as I2, I4, I6, I8, I10, I12, I14, and I16. The odd group is further divisible into a first subgroup, such as induction coils I1, I5, I9, and I13, and a second subgroup, such as induction coils I3, I7, I11, and I15. The first subgroup of the odd group is given by selecting every second odd induction coil, such as I1, I5, I9, and I13, and the second subgroup of the odd group is given by selecting the remaining every second odd induction coil, such as I3, I7, I11, and I15. The even group can further be divided into a first subgroup, such as the induction coils I2, I6, I10 and I14, and into a second subgroup, such as the induction coils I4, I8, I12 and I16.The first subgroup of the even group is given by selecting every second even induction coil, such as I2, I6, I10, and I14, and the second subgroup of the even group is given by selecting the remaining every second even induction coil, such as I4, I8, I12, and I16. As from . Fig. As can be seen in Figure 7, the induction coils I1 and I5, which are arranged within the first 180°, of the first subgroup of the odd group, and the induction coils I3 and I7, which are arranged within the first 180°, of the second subgroup of the odd group, and the excitation coils F1, F2, F3 and F4, which are arranged within the first 90°, work together with the diodes D1 and D2 to form a rectifier circuit C5, which is designed as a closed circuit.

[0071] In this rectifier circuit C5, the induction coils I1 and I5, which are arranged within the first 180°, of the first subgroup of the odd group, i.e., the induction coils given by selecting every fourth induction coil within the first 180°, and the diode D5 are connected in series; the induction coils I3 and I7, which are arranged within the first 180°, of the second subgroup of the odd group, i.e., the induction coils given by selecting every fourth induction coil within the first 180°, and the diode D6 are connected in series; and the excitation coils F1, F2, F3 and F4, which are arranged within the first 90°, are connected in series.

[0072] One series circuit (which represents a first series circuit according to the claims) consisting of the induction coils I1 and I5 (which are arranged within the first 180°) of the first subgroup of the odd group and the diode D5, and the other series circuit (which represents a second series circuit according to the claims) consisting of the induction coils I3 and I7 (which are arranged within the first 180°) of the second subgroup of the odd group and the diode D6 are connected in parallel, and then connected to the excitation coils F1, F2, F3 and F4, which are arranged within the first 90°, such that the cathode sides of the diodes D5 and D6 are connected to a series circuit of the excitation coils F1, F2, F3 and F4.As described above, in the rectifier circuit C5, inductive alternating current generated by each of the induction coils I1, I3, I5 and I7, which are arranged within the first 180°, is rectified by the associated diodes D5 and D6 to provide a supply of direct current to the associated excitation coils F1, F2, F3 and F4, which are arranged within the first 90°.

[0073] Further referring to Fig. 7. The induction coils I2 and I6, which are arranged within the first 180°, of the first subgroup of the even group, and the induction coils I4 and I8, which are arranged within the first 180°, of the second subgroup of the even group, and the excitation coils F5, F6, F7 and F8, which are arranged within the second 90°, work together with the diodes D7 and D8 to form the rectifier circuit C6, which is designed as a closed circuit.

[0074] In this rectifier circuit C6, the induction coils I2 and I6, which are arranged within the first 180°, of the first subgroup of the even group, i.e., the induction coils given by selecting every fourth induction coil within the first 180°, and the diode D7 are connected in series; the induction coils I4 and I8, which are arranged within the first 180°, of the second subgroup of the even group, i.e., the induction coils given by selecting every fourth induction coil within the first 180°, and the diode D8 are connected in series; and the excitation coils F5, F6, F7 and F8, which are arranged within the second 90°, are connected in series.

[0075] One series circuit (which represents the first series circuit according to the claims) consisting of the induction coils I2 and I6, which are arranged within the first 180°, the first subgroup of the even group and the diode D7, and the other series circuit (which represents the second series circuit according to the claims) consisting of the induction coils I4 and I8, which are arranged within the first 180°, the second subgroup of the even group and the diode D8 are connected in parallel and are connected to the excitation coils F5, F6, F7 and F8, which are arranged within the second 90°, such that the cathode sides of the diodes D7 and D8 are connected to a series circuit of the excitation coils F5, F6, F7 and F8.As described, in the rectifier circuit C6, inductive alternating current generated by each of the induction coils I2, I4, I6 and I8 is rectified by the associated diodes D7 and D8 to provide a supply of excitation DC current to the excitation coils F5, F6, F7 and F8, which are arranged within the second 90°.

[0076] As described, each of the diodes D5, D6, D7 and D8 represents the rectifier element according to the claims.

[0077] The circuit setup described above enables the rotor teeth 302 to operate as electromagnets because induced currents generated by the induction coils I are rectified and used as excitation currents to excite the excitation coils F.

[0078] According to this circuit configuration with respect to diodes D5, D6, D7, and D8, the number of diodes required is limited by the use of such series connections, even if an increase in the number of poles is necessary due to an increase in the number of induction coils I and excitation coils F. To avoid using a large number of diodes, the circuit configuration forms a star-terminal half-wave rectifier circuit to provide an output current by performing half-wave rectification after conversion of one of the supplied induction currents, instead of using the widely used full-wave rectifier circuit of the H-bridge type.

[0079] The excitation coils F of the rectifier circuits C5 and C6 are wound around the two adjacent rotor teeth 302 in opposite winding directions. One of the two adjacent rotor teeth 302, which forms part of a magnetic circuit, is magnetized such that it acts as an electromagnet whose S-pole is opposite the outer rotor 200 in order to induce a magnetic flux from the adjacent pole shoe segment 201A of the outer rotor 20. Furthermore, the other of the two adjacent rotor teeth 302 is magnetized such that it acts as an electromagnet whose N-pole is opposite the outer rotor 20 in order to induce a magnetic flux to the outer rotor 200.

[0080] The principle of torque generation in the rotating electric machine 1 is now described. Among the magnetic flux components that come out of the stator 100, flow through the outer rotor 200 to couple with the inner rotor 300, at least one component, modulated by the rotation of the outer rotor 200, is synchronized with the rotation of the inner rotor 300 and couples with the inner rotor 300.

[0081] On the other hand, the magnetic flux coupled to the induction coils I of the inner rotor 300 contains at least one component that varies without being modulated by the rotation of the outer rotor 200 (i.e., without being synchronized with the rotation of the inner rotor 300). This component causes the induction coils I to generate an induced alternating current. The induced current is rectified by the diodes D1, D2, D3, and D4 to provide excitation current to energize the excitation coils F, causing the rotor teeth 302 to act as electromagnets to generate excitation magnetic flux. This results in the production of torque within the rotating electric machine 1.

[0082] It is noted that the supply of current from an alternating current source to the armature coils 104, which are wound with distributed winding, causes the generation of magnetic flux, which comes out of the stator teeth 102 of the stator 100, flows through the pole shoe segments 201A of the outer rotor 200 and couples with the rotor teeth 302 of the inner rotor 300.

[0083] Fig. Figure 8 shows magnetic circuits through which the asynchronous magnetic flux, which couples with the inner rotor 300, flows. As can be seen from Fig.As can be seen in Figure 8, the excitation coils F are caused to generate an induced electromotive force because the magnetic flux couples uniformly with the rotor teeth 302 of the inner rotor 300. However, the use of the induced electromotive force by the excitation coils F presents the problem that the phase relationship between the parallel-connected induction coils I (i.e., the first series connection and the second series connection) is broken due to interference with the induced electromotive forces by the induction coils I. Consequently, this increases the torque ripple resulting from the variation in the induced current because full-wave rectification is not permitted.

[0084] Regarding this problem, the excitation coils F are connected to the induction coils I in order to cancel out the induced electromotive forces from the excitation coils F, so that the induced electromotive forces from the excitation coils F do not interfere with the induced electromotive forces from the induction coils I. In other words, in the second embodiment, the excitation coils F, which are arranged within a 90° mechanical angle, are connected in series with the induction coils I.

[0085] Such a connection makes it possible to carry out full-wave rectification with currents flowing through the excitation coils F, while maintaining the phase relationship between the parallel-connected induction coils I (i.e., the first series connection and the second series connection).

[0086] Furthermore, the present embodiment considerably reduces the torque ripple compared to the case where only those rotor windings that have the same phase of the induced electromotive force are connected in series, as is the case in the first embodiment, because the full-wave rectification is carried out with induced currents.

[0087] Furthermore, the cost and weight of the components are reduced because the full-wave rectification reduces the amplitude of the rotor current to allow the selection of diodes with a small permissible current value.

[0088] Furthermore, the torque characteristics are improved, while the magnetomotive force (MMF) is maintained by the excitation current without excessively increasing the voltage drop in the self-inductance, even when a difference frequency (i.e., a difference in frequency between the rotating stator magnetic field and the rotor speed) becomes large, by connecting the excitation coils F and the induction coils I to cancel the induced electromotive forces from the excitation coils F.

[0089] As described, in the second embodiment the rotating electrical machine 1 comprises: the induction coils I, each wound with concentrated winding around the rotor teeth 302, such that the two adjacent induction coils I are wound in opposite winding directions, and which are arranged radially around the central longitudinal axis such that the induction coils I are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C; the excitation coils F, each wound with concentrated winding around the rotor teeth 302, such that the two adjacent excitation coils F are wound in opposite winding directions, and which are arranged radially around the central longitudinal axis 1C such that the excitation coils F are spaced apart from each other along the arc length of the circle around the central longitudinal axis 1C;and rectifier circuits C5 and C6, each comprising: a first series circuit in which a plurality of induction coils I, whose current phases are the same, and a diode are connected in series, and a second series circuit in which another plurality of induction coils I, whose current phases are the same, and another diode are connected in series.

[0090] This smooths out the torque ripple that arises from variations in the induced current, because the first and second series circuits of each of the rectifier circuits C5 and C6 have different ripple currents.

[0091] Furthermore, each of the rectifier circuits C5 and C6 comprises the first series circuit in which the plurality of induction coils I, whose current phases are the same, and a diode are connected in series, and the second series circuit in which the other plurality of induction coils I, whose current phases are the same, and the other diode are connected in series, the first and the second series circuit being connected in parallel.

[0092] This significantly reduces torque ripple because the full-wave rectification is performed using the induction currents.

[0093] Furthermore, each of the rectifier circuits C5 and C6 is a closed circuit in which the multitude of excitation coils F is connected in series with the parallel connection of the first and the second series circuit in order to cancel out the induced electromagnetic forces from the excitation coils F with each other.

[0094] Such a connection makes it possible to carry out full-wave rectification with currents flowing through the excitation coils F, while maintaining the phase relationship between the parallel-connected first and second series circuits, thereby considerably reducing the torque ripple.

[0095] Although in the first and second embodiments the rotating electric machine 1 is an inner rotor type with a radial gap structure, the rotating electric machine 1 can be implemented with an axial gap structure or an outer rotor structure. Furthermore, the rotating electric machine 1 uses the pole combination such that the number of pole pairs in the stator is 100 4, the number of pole pairs in the outer rotor is 200 12, and the number of pole pairs in the inner rotor is 300 8; however, it can use other different combinations.

[0096] Additionally, a copper wire, an aluminum conductor wire, or a stranded wire can be used as each of the coils. The soft magnetic composite (SMC) core made of mixed soft magnetic material can be used instead of the laminated electromagnetic steel plates to form the magnetic path component 201 or the rotor core 301.

[0097] A magnetic modulator comprising a magnetic path component 201 and non-magnetic elements 202 can be an inner rotor, and an excitation rotor comprising rotor windings 330 or excitation coils F and induction coils I can be an outer rotor.

[0098] The present invention is applicable to rotating electrical machines in which induced electromotive force is generated on windings around a rotor without magnetic modulation when magnetic flux from spatial harmonics of a stator couples with the rotor.

[0099] The use of the rotating electric machine 1 is not limited to automotive use and it is possible, for example, to use it appropriately in wind power generation or to use it as a drive source in machine tools. [List of reference symbols] 1 rotating electric machine 100 Stator 104 Armature coil 200 outer rotor (second rotor) 201 Magnetic path component 202 non-magnetic element 300 inner rotor (rotor, first rotor) 302 rotor teeth (salient poles) 330-1 - 330-16 Rotor windings C1, C2, C3, C4, C5, C6 Rectifier circuit D1, D2, D3, D4, D5, D6, D7, D8 Diode (rectifier element) F1, F2, F3, F4, F5, F6, F7, F8 excitation coil I1, I2, I3, I4, I5, I6, I7, I8 induction coil

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