Reluctance motor

Abstract

Reluctance motor (10) comprising: a stator (11) provided with drive coils (14) into which multiphase drive currents are applied; and a rotor (21) provided with a plurality of salient poles which receive a primary rotational force when magnetic fluxes generated in the drive coils (14) are coupled to the rotor (21), wherein the rotor (21) comprises: Induction pole coils (27, 27A, 27B) which are arranged on magnetic paths on which spatial harmonics superimposed on the magnetic fluxes generated in the drive coils (14) are coupled to the rotor side, so that induced currents in the induction pole coils (27, 27A, 27B) can be generated due to the spatial harmonics of the magnetic fluxes; Rectifier elements (29, 29A, 29B) which rectify the induced currents generated in the induction pole coils (27, 27A, 27B); and electromagnetic coils (28, 28A, 28B) to which the induced currents rectified by the rectifier elements (29, 29A, 29B) are directed as field currents, so that the electromagnetic coils (28, 28A, 28B) can be self-excited in order to generate an electromagnetic force as an auxiliary rotational force to support the primary rotational force, wherein the induction pole coils (27, 27A, 27B) are arranged between adjacent salient poles of the rotor (21), wherein core materials (27a) made of a magnetic substance are arranged between adjacent salient poles of the rotor (21), wherein the induction pole coils (27, 27A, 27B) are concentratedly wound on the core material (27a), and wherein the core materials (27a) are fixed on the rotor (21) via a non-magnetic substance.

Description

REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority from Japanese patent application JP 2013-055860, filed on March 19, 2013, the entire contents of which are incorporated herein by reference. AREA OF INVENTION

[0002] The present invention relates to a reluctance motor. In particular, it relates to a reluctance motor which has a self-excitation function in order to achieve highly efficient rotation. BACKGROUND OF THE INVENTION

[0003] Reluctance motors are used as drive sources in various types of drive devices. Each reluctance motor has the problem that it is difficult to achieve high torque, especially if it is a type that uses only reluctance torque, compared to a motor (electric motor) that is driven using magnetic torque generated by permanent magnets embedded in the rotor.

[0004] In particular, when a motor is attached to an electric hybrid vehicle or an electric vehicle that requires high torque, the motor often uses an IPM structure (IPM: Interior Permanent Magnet), in which permanent magnets, such as neodymium magnets with a strong magnetic force, are embedded in a V-shape in a rotor, so that both magnetic torque and reluctance torque can be used effectively.

[0005] For example, it has been suggested that a reluctance motor could use a self-excitation function to improve efficiency, as proposed in Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pp. 18-26. The aim was to improve characteristics such as torque in a reluctance motor that could be manufactured cost-effectively as an in-vehicle engine.

[0006] In the self-excitation system disclosed in Sakutaro Nonaka, "Self-Excitation Type Single-Phase Synchronous Motor," IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, magnetic fluxes with a higher frequency than the fundamental frequency of the drive currents supplied to the stator-side drive coils are coupled to the rotor side to generate induced currents in self-excitation coils arranged on the rotor side. In this self-excitation system, the induced currents are rectified in half-waves and then fed back to the self-excitation coils, allowing them to also function as electromagnetic coils.

[0007] However, in the self-excitation function disclosed in Sakutaro Nonaka, "Self-Excitation Type Single-Phase Synchronous Motor", IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, the self-excitation coils also serve as the electromagnetic coils. Consequently, magnetic interference occurs, so that the induced currents cannot be generated efficiently, and the generated electromagnetic force is thus also weakened.

[0008] Additionally, in the structure disclosed in Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, the self-excitation coils are arranged in deep sections that are isolated from an outer surface of the rotor. High-frequency components (spatial harmonics) of the magnetic fluxes cannot reach the deep sections of the rotor (they are not coupled to them), and only very small induced currents can be generated in the self-excitation coils.

[0009] Furthermore, a self-excitation type motor was also proposed in JP H10 - 271 781 A. However, it exhibits the same problems because induced currents cannot be generated efficiently in the same way.

[0010] Additionally, JP 2010-22185A proposed that high-frequency currents be separately applied to stator-side coils to generate excitation currents in rotor-side self-excitation coils. However, this requires an external excitation energy input, meaning that high-efficiency driving cannot be expected (a reduction in efficiency is unavoidable).

[0011] Another example of prior art is WO 2012 / 110883 A2. Here, a stator has multiphase stator coils wound around a stator core using concentrated winding. A rotor has rotor coils wound circumferentially on several sections of a rotor core and diodes, which serve as a rectifier unit connected to the rotor coils and alternately vary the magnetic properties of the respective rotor coils circumferentially. A drive system for a rotating electric machine includes a diminishing pulse superposition unit that superimposes diminishing pulse currents for a pulsed diminishing of a q-axis current command to drive currents through the stator coils. SUMMARY OF THE INVENTION

[0012] Therefore, the object of the invention is to provide a reluctance motor which can collect loss energy in order to achieve the self-excitation function and which can be rotated with high efficiency in order to achieve an improvement with respect to torque.

[0013] The problem is solved by the reluctance motor according to independent claim 1. Advantageous modifications are found in dependent claims 2 and 3.

[0014] A first aspect of the invention relates to a reluctance motor comprising: a stator provided with drive coils into which multiphase drive currents are applied; and a rotor provided with a plurality of salient poles which receive a primary rotational force when magnetic fluxes generated in the drive coils are coupled to the rotor, wherein the rotor comprises: induction pole coils arranged on magnetic paths on which spatial harmonics superimposed on the magnetic fluxes generated in the drive coils are coupled to the rotor side, so that induced currents can be generated in the induction pole coils due to the spatial harmonics of the magnetic fluxes; rectifier elements which rectify the induced currents generated in the induction pole coils;and electromagnetic coils to which the induced currents rectified by the rectifier elements are directed as field currents, so that the electromagnetic coils can be self-excited in order to generate an electromagnetic force as an auxiliary rotational force to support the primary rotational force, and wherein the induction pole coils and the electromagnetic coils do not serve mutual purposes, but are arranged individually on the rotor.

[0015] A second aspect of the invention is characterized in that the induction pole coils are arranged between adjacent salient poles of the rotor.

[0016] A third aspect of the invention is characterized in that each of the induction pole coils has a structure which is magnetically independent of component materials, with the exception that the induction pole coil has a core material on which the induction pole coil is wound.

[0017] A fourth aspect of the invention is characterized in that core materials on which the induction pole coils are wound are made of a magnetic substance.

[0018] A fifth aspect of the invention is characterized in that the ratio of a number P of the salient poles of the rotor to a number S of slots in which the drive coils of the stator are arranged is set to P / S = 2 / 3.

[0019] Thus, according to the first aspect of the invention, magnetic fluxes generated in the stator-side coils are coupled to the rotor-side salient poles to generate a primary rotational force. At this point, spatial harmonics superimposed on the magnetic fluxes are coupled to the rotor-side induction pole coils to generate induced currents. The induced currents are rectified by rectifier elements and supplied (guided) as field currents to the electromagnetic coils, so that electromagnetic forces (magnetic fluxes) can be generated in the electromagnetic coils to act with the magnetic fluxes from the stator side. In this way, an auxiliary rotational force can be generated to assist the primary rotational force and rotate the rotor.

[0020] Therefore, it is not necessary to supply energy separately to the rotor-side electromagnetic coils. Spatial harmonics of the magnetic fluxes (which cause iron loss), which cannot be effectively utilized according to the prior art, can be collected to rotate the rotor with high efficiency. This prevents the same currents from flowing into the induction pole coils and the electromagnetic coils and interfering with each other, thus avoiding losses. Consequently, wasted energy can be effectively collected to improve the torque of the reluctance motor.

[0021] According to the second aspect of the invention, the spatial harmonics of the magnetic fluxes from the stator can be efficiently coupled to the induction pole coils, which are arranged next to the salient poles, i.e., on the outer circumferential surface of the rotor. This allows the spatial harmonics of the magnetic fluxes to be efficiently collected in order to effectively self-excite the induction pole coils, thereby supplying field currents with high capacitance to the electromagnetic coils. Consequently, a highly efficient self-excitation function can be formed with a simple structure.

[0022] According to the third aspect of the invention, the magnetic fluxes generated around the induction pole coils can be prevented from interfering with each other, thus preventing self-excitation from being hindered. Additionally, the induction pole coils can be prevented from causing a reduction in the salient pole ratio. Consequently, an improvement in the torque effectively generated due to self-excitation can be achieved, while a reduction in the reluctance torque is avoided.

[0023] According to the fourth aspect of the invention, the magnetic permeability within the induction pole coils can be increased so that magnetic fluxes of the spatial harmonics from the stator can be efficiently coupled to the induction pole coils. Consequently, the energy loss recovery rate can be improved. Thus, the torque of the reluctance motor can be improved more effectively.

[0024] According to the fifth aspect of the invention, the ratio of the number P of rotor salient poles to the number S of stator slots can be optimized so that the magnetic flux density can be uniformly distributed to suppress electromagnetic vibration of the stator. Consequently, energy loss caused by electromagnetic vibration can be reduced, and wasted energy can be efficiently collected. Due to the reduction of electromagnetic vibration, electromagnetic noise can also be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a partially enlarged radial sectional view showing a schematic configuration of a reluctance motor according to an embodiment of the invention. Fig. Figure 2 is a partially enlarged radial sectional view showing a schematic configuration of a basic structure of the embodiment. Fig. Figure 3 is a partially enlarged radial sectional view showing a schematic configuration of an unimproved prototype structure according to the embodiment. Fig. Figure 4 is a circuit diagram of a simple model to explain, in an easy-to-understand way, a circuit configuration in which induction pole coils and electromagnetic coils are connected to each other by diodes. Fig. Figure 5 is a graph showing the waveform of an induced current emanating from an induction pole coil located in Fig. The circuit shown in section 4 is extracted. Fig. Figure 6 is a graph showing the waveform of an induced current emanating from a coil connected to the induction pole coil. Fig. 5 from the in Fig. The circuit shown in section 4 has a different induction pole coil extracted and is inverted. Fig. Figure 7 is a graph showing a synthetic waveform in which the induced currents from Fig. 5 and Fig. 6 are combined. Fig. Figure 8 is a graph showing the waveform of an induced current in each induced pole coil in the reluctance motor with the in Fig. The 3 shown unimproved prototype structure is produced. Fig. 9 is a graph that shows a combination of the reluctance motor and the in Fig. 2 basic structure shown, obtained torque and a torque from the reluctance motor with the in Fig. 3 shown non-improved prototype structure using the in Fig. The induced current shown in section 8 is obtained. Fig. Figure 10 is a conceptual diagram showing the distribution of a spatial harmonic magnetic flux density in the reluctance motor with the in Fig. Figure 3 shows the unimproved prototype structure in vector representation. Fig. Figure 11 is a conceptual view which describes the distribution of the spatial harmonic magnetic flux density in the reluctance motor according to the one in Fig. The exemplary embodiment shown in 1 is depicted in vector representation. Fig. 12 is a graph showing the waveform of a current in each induction pole coil in the reluctance motor according to the diagram in Fig. 1 shown embodiment generated induced current, and the waveform of a current in the reluctance motor with the in Fig. The induced current generated by the 3 shown non-improved prototype structure is demonstrated. Fig. Figure 13 is a graph showing the torque produced using an induced current of the reluctance motor according to the diagram in Fig. 1 shown embodiment, and the torque which is obtained using an induced current of the reluctance motor with the in Fig. The 3 shown unimproved prototype structure is preserved, as shown. Fig. Figure 14 is a distorted top view showing an example of electromagnetic vibration generated due to the ratio between the number of stator-side slots and the number of rotor-side salient poles, with the vibration viewed from the axis. Fig. Figure 15 is a graph showing the quality of the induced currents generated due to the ratio between the number of stator-side slots and the number of rotor-side salient poles. Fig. Figure 16 is a conceptual model diagram showing a correspondence between the number of stator-side slots and the number of rotor-side salient poles in the partially enlarged radial sectional view of the reluctance motor according to the embodiment. Fig. Figure 17 is a graph showing the waveform of a spatial harmonic component superimposed on the magnetic flux from the stator side coupled to the rotor side in the reluctance motor according to the embodiment. Fig. Figure 18 is a graph showing the strength of the coupling magnetic flux according to each spatial harmonic magnetic flux of the 3fth order as a result of a Fourier series expansion of the in Fig. Figure 17 shows the waveform of the magnetic flux. Fig. Figure 19 is a conceptual diagram in which the magnetic flux density distribution of the third spatial harmonic magnetic flux, whose coupling magnetic flux strength in Fig. Figure 18 is shown in vector representation. Fig. Figure 20 is a conceptual diagram in which the magnetic flux density distribution of the sixth spatial harmonic magnetic flux, whose coupling magnetic flux strength in Fig. Figure 18 is shown in vector representation. Fig. Figure 21 is a conceptual diagram in which the magnetic flux density distribution of the ninth spatial harmonic magnetic flux, whose coupling magnetic flux strength in Fig. Figure 18 is shown in vector representation. Fig. Figure 22 is a perspective view in which a reluctance motor according to another operating mode of the embodiment is partially cut out. Fig. 23 is a partially enlarged radial sectional view showing a schematic configuration of a reluctance motor according to one derived from the Fig. 22 different operating modes of the embodiment in the same way as in Fig. 1 is shown. [List of reference symbols] 10 Reluctance motor 11 Stator 12 stator teeth 12b Collar section 13, 23 slots 14 Drive coil 21 Rotor 22 rotor teeth 27, 27A, 27B induction pole coil 27a Core material 28, 28A, 28B electromagnetic coil 29, 29A, 29B Diode DETAILED DESCRIPTION OF THE INVENTION

[0025] An embodiment of the invention is described in detail below with reference to the drawings. Fig. Figures 1 to 21 are views to explain a reluctance motor according to an embodiment of the invention. Fig. Figures 1 to 3 are radial sectional views of reluctance motors, each shown corresponding to a mechanical angle of 60° around its axis. The reluctance motor is manufactured such that it has a structure in which the depicted part corresponding to the mechanical angle of 60° is periodically repeated.

[0026] In Fig. 1. A reluctance motor 10 starts at a reluctance motor 10B with a in Fig. The basic structure shown in section 2 uses a structure in which the one in Fig. The problem inherent in the reluctance motor 10D shown in Figure 3 and caused by the reluctance motor 10B can be solved. For example, the reluctance motor 10 exhibits suitable performance when mounted as a drive source similar to an internal combustion engine on a vehicle or in a wheel of a hybrid or electric vehicle. Furthermore, each of the reluctance motors 10, 10B, and 10D described here is manufactured in a manner different from that described in JP-A-2010-22185 and has a structure in which no external energy needs to be supplied to a rotor. (Basic structure of the reluctance motor)

[0027] First, the reluctance motor 10B, as shown in Fig. Figure 2 shows a stator 11, which is essentially cylindrical, and a rotor 21, which is rotatably inserted in the stator 11, so that a rotating shaft of the rotor 21 can be fixed in alignment with the axis.

[0028] In the stator 11, a plurality of stator teeth 12, each in the form of a radially extending salient pole, are uniformly arranged around the circumference so that inner circumferential surfaces 12a and outer circumferential surfaces 22a of the rotor 21 (rotor teeth 22) can face each other across a distance G. On each stator tooth 12, three-phase windings corresponding to three phases are individually and concentratedly wound to form a drive coil 14 using a slot 13, which is a gap formed between the side surface of the stator tooth 12 and the side surface of another adjacent tooth. The stator tooth 12 acts as an electromagnet, generating a magnetic flux to rotate the rotor 21, which is located inside opposite the stator tooth 12, when a drive current is supplied to the drive coil 14.

[0029] In the rotor 21, a plurality of rotor teeth (salient poles) 22, each in the form of a radially extending salient pole, are arranged uniformly around the circumference in the same manner as the stator teeth 12. The rotor teeth 22 are designed such that the total number of circumferential surfaces differs from that of the stator teeth 12, so that the outer circumferential surfaces 22a of the rotor teeth 22 can mate closely and completely with the inner circumferential surfaces 12a of the stator teeth 12 when the rotor teeth 22 rotate relative to them.

[0030] Thus, in the reluctance motor 10B, magnetic fluxes generated by electricity conducted to the drive coils 14 in the slots 13 of the stator 11 can be coupled from the inner circumferential surfaces 12a of the stator teeth 12 to the opposite outer circumferential surfaces 22a of the rotor teeth 22. The rotor 21 can be rotated relatively by the effect of a reluctance torque (primary rotational force), which tends to form the shortest magnetic paths through which the magnetic fluxes flow. Consequently, the electrical energy input as electricity, which is conducted by the rotating shaft that rotates completely with the rotor 21 rotating relatively within the stator 11, can be output as mechanical energy by the reluctance motor 10B.

[0031] In this reluctance motor 10B, magnetic fluxes contributing to the torque cannot be generated within the rotor 21. Instead, spatial harmonics are superimposed on the magnetic fluxes coupled from the inner circumferential surfaces 12a of the stator teeth 12 to the outer circumferential surfaces 22a of the rotor teeth 22. Therefore, by using the change in the magnetic flux densities of the spatial harmonics of the magnetic fluxes coupled from the stator side 11 to the rotor side 21, induced currents can be generated in built-in coils to obtain electromagnetic forces.

[0032] Specifically, a drive energy at the fundamental frequency is supplied to the drive coils 14 of the stator 11 to rotate the rotor 21 (rotor teeth 22) by means of main magnetic fluxes that vary with the fundamental frequency. Consequently, there is no change in the coupling magnetic fluxes, even if the coils on the rotor side 21 are simply arranged. Thus, no induced currents are generated.

[0033] On the other hand, the spatial harmonics superimposed on the magnetic fluxes are coupled from the outer circumferential surfaces 22a to the rotor teeth 22, while varying temporally from the fundamental frequency in a different cycle. Therefore, the spatial harmonics superimposed on the magnetic fluxes of the fundamental frequency can efficiently generate induced currents in the coils arranged in the vicinity of the outer circumferential surfaces 22a of the rotor teeth 22 without any separate input. Consequently, the spatial harmonic magnetic fluxes, which can cause iron losses, can be stored as energy for self-excitation. (Improved structure of the reluctance motor)

[0034] As in Fig. As shown in Figure 3, in the reluctance motor 10D, windings are wound on each rotor tooth 22 using a slot 23, which is a gap formed between the side surface of the rotor tooth 22 and the side surface of another adjacent tooth. Due to the concentrated windings thus formed in two stages in the radial direction, each induction pole coil 25 and each electromagnetic coil 26 is arranged.

[0035] The induction pole coils 25 are arranged on the sides of the outer circumferential surfaces 22a of the rotor teeth 22. The electromagnetic coils 26 are arranged on the axial side of the rotor teeth 22. The induction pole coils 25 and the electromagnetic coils 26 are connected and operated in mutual cooperation to serve as a circuit configuration that provides the Fig. The one shown in Figure 4 is similar to the one described below. Furthermore, in the reluctance motor 10D, the induction pole coils 25 correspond to induction pole coils 27A and 27B respectively. Fig. 4, and the electromagnetic coils 26 correspond to the electromagnetic coils 28A and 28B in a similar manner.

[0036] The induction pole coils 25 generate induced currents due to the spatial harmonics (the change in magnetic flux density) of the magnetic fluxes coupled from the inner circumferential surfaces 12a of the stator teeth 12 to the outer circumferential surfaces 22a of the rotor teeth 22, and supply the induced currents to the electromagnetic coils 26. The electromagnetic coils 26 are self-excited by the induced currents received from the induction pole coils 25, which serve as field currents. Thus, magnetic fluxes (electromagnetic forces) can be generated.

[0037] In this way, in the reluctance motor 10D, the electromagnetic coils 26, which receive the induced currents flowing into the induction pole coils 25, can generate magnetic fluxes due to the spatial harmonics of the magnetic fluxes, so that the generated magnetic fluxes can be coupled from the outer circumferential surfaces 22a of the rotor teeth 22 to the inner circumferential surfaces 12a of the stator teeth 12. Therefore, the reluctance torque (auxiliary rotational force), which seeks to form the shortest magnetic paths through which the coupling magnetic fluxes flow, differing from the magnetic fluxes of the drive coils 14 that generate the primary rotational force, can be obtained to assist the relative rotation of the rotor 21.

[0038] Consequently, the reluctance motor 10D can store the spatial harmonics of the magnetic fluxes as energy, which cause losses in the reluctance motor 10B. For example, the constant torque in the reluctance motor 10D can be improved by approximately 31.9% compared to that in the reluctance motor 10B if the reluctance motor 10D and the reluctance motor 10B are driven with the same stator structure under the same drive conditions (rotational speed, current value, and current phase angle). Additionally, torque ripple in the reluctance motor 10D can be reduced (see Fig. 9, which is described below).

[0039] Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, also discloses an improved structure of the reluctance motor 10B. According to the self-excitation technique disclosed in Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, coils are wound on the rotor teeth 22 so that magnetic fluxes with a higher frequency than the fundamental frequency can be coupled to the rotor-side coils to generate induced currents. The induced currents are rectified by rectifier elements (diodes) into half-wavelengths and returned. In this way, the rotor-side coils serve as self-excitation-type electromagnets.

[0040] However, the self-excitation technique revealed in Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Volume 78 No. 842, November 1958, pages 18-26, exhibits the following problems. 1. Since the rotor-side coils serve both as coils for generating induced currents and as coils for supplying rectified induced currents as field currents, magnetic interferences occur, so that the induced currents cannot be generated efficiently and a magnetomotive force also becomes very small. 2. Higher-order harmonics of magnetic fluxes with a frequency higher than the fundamental frequency are distributed only in the vicinity of the outer circumferential surfaces 22a, even when the magnetic fluxes are coupled to the rotors 21 (rotor teeth 22). Consequently, if coils are arranged on the axial side, only very small induced currents can be generated. Moreover, it is practically impossible to arrange the rotor-side coils in the vicinity of the outer circumferential surfaces 22a of the rotor teeth 22. Even if, for example, a very small conductor wire with a thinner diameter than any coil is wound, the conductor resistance of the coil increases, thus increasing copper loss. Therefore, it is difficult for the coil to function as an efficient electromagnet. Additionally, there is also the concern that the rotor surface may come into contact with the stator side. 3. If the coils on the stator side 11 are designed as distributed windings, there is a tendency for higher-order harmonics to be superimposed on the magnetic fluxes, so that only smaller induced currents due to the higher-order harmonics of the magnetic fluxes, as described above, can be expected. Distributed windings are not suitable with regard to the way the coils are wound. 4. Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pages 18-26, discloses that the rotor-side coils are excited by the harmonic magnetic fluxes, which have a frequency twice that of the fundamental frequency. Low points occur when induced currents generated by second harmonic magnetic fluxes are rectified and combined (see Fig. 8, which is described below). Since, in addition, the induced currents become larger with an increase in the time rate of change of the magnetic fluxes, harmonic magnetic fluxes are preferred whose order is not too high, but rather around the third order. (Basic structure of the reluctance motor 10 according to the embodiment)

[0041] With reference to Fig. 1. In the reluctance motor 10 according to the exemplary embodiment, concentrated windings are used, wherein three-phase windings corresponding to three phases are individually wound on each stator tooth 12, in each slot 13 on the stator side 11 in order to form a drive coil 14, which acts as an electromagnet, as in Fig. Figure 3 shows the following. In the reluctance motor 10, the induction pole coils 25 of the reluctance motor 10D are replaced by induction pole coils 27, and the electromagnetic coils 26 are replaced by electromagnetic coils 28.

[0042] Additionally, on the rotor side 21, each induction pole coil 27, which is condensed and wound on each core material 27a, is fully inserted in each slot 23, and a concentrated winding of one stage is formed over each rotor tooth 22, so that each electromagnetic coil 28 is arranged. The core material 27a, in which electromagnetic steel sheets (magnetic substance) are laminated, is used for the induction pole coil 27. Accordingly, the magnetic permeability is increased, so that the magnetic fluxes can be coupled at high density. The induction pole coils 27 are located opposite the inner circumferential surfaces 12a of the stator teeth 12 via a very small air gap G. Thus, several spatial harmonic magnetic fluxes can be coupled.A magnetic field analysis is performed to verify spatial harmonic magnetic paths so that the induction pole coils 27 can effectively utilize the third spatial harmonic components of the magnetic fluxes coupled from the inner surfaces 12a of the stator teeth 12 to the outer surfaces 22a of the rotor teeth 22. Thus, the induction pole coils 27 are arranged to efficiently generate induced currents. Furthermore, each induction pole coil 27 is positioned between adjacent rotor teeth 22 to ensure sufficient spacing between the induction pole coil 27 and the corresponding electromagnetic coil 28.

[0043] When the condensed winding structure is used in this way, each induction pole coil 27 and each electromagnetic coil 28 can be miniaturized as a whole without the need for circumferential windings over a multitude of slots. Additionally, the induction pole coils 27 can reduce copper losses on the primary side and efficiently generate induced currents due to the coupling of the third spatial harmonic magnetic fluxes, which are of low order. Thus, a collectable energy loss can be increased.

[0044] Additionally, due to the use of the third spatial harmonic magnetic fluxes, induced currents can be generated more effectively in the induction pole coils 27 than if second spatial harmonic magnetic fluxes were used, as described in Sakutaro Nonaka, "Self-Excitation Type Single-Phase Synchronous Motor," IEEJ Transactions, Vol. 78, No. 842, November 1958, pages 18-26. In particular, the use of the third spatial harmonic magnetic fluxes, compared to the use of the second spatial harmonic magnetic fluxes, allows the time variation of the magnetic fluxes to be increased, thus increasing the induced currents and thereby more efficiently collecting the energy loss. In the case described in Sakutaro Nonaka, "Self-Excitation Type Single-Phase Synchronous Motor," IEEJ Transactions, Vol. 78, No.The structure disclosed in 842, November 1958, pages 18-26, shows coils wound on axially deep sections of the rotor, but does not consider the areas where the spatial harmonics are coupled, and the spatial harmonics cannot be used effectively.

[0045] Each induction pole coil 27 is arranged in each slot 23 between adjacent outer circumferential surfaces 22a of the rotor teeth 22 to be magnetically independent. Each electromagnetic coil 28 is wound over the entire length of each rotor tooth 22, so that the entire electromagnetic coil 28 can be used effectively to generate a magnetic flux. The induction pole coil 27 and the electromagnetic coil 28 are separated to prevent magnetic flux paths from interfering with each other, thus reducing magnetic interference for efficient induced current generation. Additionally, the induction pole coils 27 and the electromagnetic coils 28 can effectively function as electromagnets to generate magnetic fluxes.

[0046] The induction pole coils 27 are formed as lumped windings in the same circumferential windings with respect to the radial direction of the rotor 21. The induction pole coils 27 are arranged in the circumferential direction of the rotor 21 such that they are connected in parallel with each other. The electromagnetic coils 28 are formed as lumped windings in circumferential windings such that adjacent electromagnetic coils 28 can be wound in opposite directions to each other with respect to the radial direction of the rotor 21. All electromagnetic coils 28 are connected in series with each other, so that each section on the outer circumferential side of the rotor 21 and each section on the axial side of the rotor 21 are connected alternately.

[0047] As in Fig. As shown in Figure 4, opposite end sections of the series connection, in which all electromagnetic coils 28 are connected in series, are connected to opposite end sections of the induction pole coils 27 (27A and 27B), which are connected in parallel, via diodes 29 (29A and 29B). Even if the induction pole coils 27 and the electromagnetic coils 28 (28A and 28B) are multiply polarized, the number of diodes 29 required can be reduced due to the series connection, in which all electromagnetic coils 28 are connected in series.To avoid using a large number of the diodes 29, the diodes 29 do not form a general H-bridge type full-wave rectifier circuit, but instead form a neutral-point terminal type half-wave rectifier circuit in which each pair of the diodes 29 is connected with a phase difference of 180°, so that an induced current output by one pair can be inverted and rectified in half-wave mode.

[0048] Thus, in the reluctance motor 10, the spatial harmonics of the magnetic fluxes coupled from the inner circumferential surfaces 12a of the stator teeth 12 to the outer circumferential surfaces 22a of the rotor teeth 22 can pass through the core materials 27a, which are made of electromagnetic steel sheets with high magnetic permeability, without interference with the electromagnetic coils 28 (without a reduction in the induced currents), so that the induction pole coils 27 can efficiently generate and collect induced currents. The induced currents generated in the induction pole coils 27 are rectified by the diodes 29 and then superimposed so that they flow into the electromagnetic coils 28, which are connected in series. Thus, the electromagnetic coils 28 can be effectively self-excited to generate high magnetic fluxes (electromagnetic forces).

[0049] Accordingly, in the reluctance motor 10, the magnetic fluxes, which are attenuated due to interference in the reluctance motor 10D, can be smoothed and effectively used by the induction pole coils 27 and the electromagnetic coils 28, which are divided independently of each other for excitation purposes and for electromagnetic purposes, so that the magnetic fluxes can be efficiently collected and output as energy.

[0050] Additionally, the induction pole coils 27 and the electromagnetic coils 28 are arranged circumferentially around the rotor 21 and are multiply polarized. Accordingly, compared to a bipolar motor described in Sakutaro Nonaka, “Self-Excitation Type Single-Phase Synchronous Motor”, IEEJ Transactions, Vol. 78 No. 842, November 1958, pp. 18-26, the amount of magnetic flux coupled to each rotor tooth 22 can be distributed circumferentially, and the electromagnetic force (reluctance torque) acting on each rotor tooth 22 can also be distributed circumferentially, thereby suppressing electromagnetic vibration. Thus, the reluctance motor 10 can be made quieter. (Specific structure of the reluctance motor 10 according to the embodiment)

[0051] The induction pole coils 27 and the electromagnetic coils 28, including the drive coils 14, are designed as windings using a winding material made of copper conductor. The use of copper conductor increases electrical conductivity and reduces losses, allowing induced currents to be generated efficiently and used as field currents. When the copper conductor is used as the wires of coils 27, 28, and 14, rectangular conductor wires are preferably used to reduce copper losses or heat losses caused by the coil resistance. Furthermore, if the coils 27, 28, and 14 are designed as upright coils wound vertically, with the shorter side facing the inner diameter surface, the distributed capacitance (stray capacitance) can be reduced to improve the frequency characteristics.Since the length of the wire's circumference is also large, any increase in resistance caused by the skin effect can be suppressed, thus preventing a decrease in efficiency. Consequently, coils 27, 28, and 14 can collect more energy loss with a small amount of copper conductor. Furthermore, the wire material of coils 27, 28, and 14 is not limited to copper conductors but can be selected according to any other purpose. For example, an aluminum busbar, whose specific gravity is one-third that of copper, can be used to reduce weight.

[0052] In the stator 11, the inner circumferential surfaces 12a of the stator teeth 12 project both forwards and backwards, forming collar sections 12b in the open slots 13. This allows spatial harmonic magnetic fluxes to be efficiently coupled to the interior of the induction pole coils 27.

[0053] The induction pole coils 27 can be fixed to the rotor side 21 together with the core materials 27a by a non-magnetic substance, such as resin, with which the electromagnetic coils 28 are attached to the rotor teeth 22. Furthermore, the induction pole coils 27 can be structured such that they are axially fixed together with the core materials 27a by a mounting end plate for attaching the axially opposite end sections of the rotor 21, or the core materials 27a can be held by bolts made of a non-magnetic substance.

[0054] In the reluctance motor 10, for example, each induction pole coil 27 is formed by 10 turns of a winding of rectangular copper wire with dimensions 2.0 mm × 1.0 mm, and each electromagnetic coil 28 is formed by 20 turns of a winding of rectangular copper wire with dimensions 2.0 mm × 1.0 mm. In the reluctance motor 10D, for example, each induction pole coil 25 is formed by 45 turns of a winding which is circular in one section with a diameter of 1 mm, and each electromagnetic coil 26 is formed by 48 turns of a winding which is circular in one section with a diameter of 1 mm.

[0055] In the reluctance motor 10, currents flow with the in Fig. Current waveforms shown in 5 to 7 are fed into the induction pole coils 27A and 27B and into the simple model in Fig. 4 electromagnetic coils 28A and 28B shown. In the reluctance motor 10D, currents flow with the same current waveforms as those flowing into the induction pole coils 27A and 27B and into the electromagnetic coils 28A and 28B, respectively into the induction pole coils 25 and the electromagnetic coils 26.

[0056] Specifically, the induced current generated in the induction pole coil 27A is rectified by the diode 29A in a half-wave pattern and is, as in Fig. As shown in Figure 5, the current is supplied downstream. The induced current generated in the induction pole coil 27B is rectified in half-waves and inverted by the diode 29B and is then, as shown in Figure 5, supplied downstream. Fig. 6 shown, fed downstream. Since the electromagnetic coils 28A and 28B are connected in series, a combined wave of the in Fig. 5 and Fig. The induced currents shown in Figure 6 flow as a field current into each of the electromagnetic coils 28A and 28B, so that the electromagnetic coils 28A and 28B can serve as electromagnets. The induction pole coils 27 (25) collect the spatial harmonics of the magnetic fluxes as energy sources, which, according to the prior art, cause losses, and the electromagnetic coils 28 (26) use the collected energy effectively to generate magnetic fluxes. The magnetic fluxes thus generated are added to the magnetic fluxes generated in the drive coils 14 of the stator 11 in order to efficiently rotate the rotor 21.

[0057] The reluctance motor 10D can generate field currents in the electromagnetic coils 26, as in Fig. Figure 8 shows how to generate this. Therefore, the reluctance motor 10D can, in comparison to the reluctance motor 10B, as shown in Figure 8, generate this. Fig. 9 shown, improving the torque property to add a reluctance torque derived from electromagnetic forces (magnetic fluxes) generated in the electromagnetic coils 26 to the same reluctance torque as that in the reluctance motor 10B.

[0058] In the reluctance motor 10D, as in Fig. As shown in Figure 8, it has been proven that the field currents generated in the electromagnetic coils 26 have third harmonics as their main components, in which a pulsation is observed three times in each electrical angular period, and it has been proven that the induced currents generated in the induction pole coils 25 are mainly derived from the third spatial harmonic magnetic fluxes.

[0059] If the magnetic flux density distribution in vector representation is based on a relation to the magnetic paths of the third spatial harmonic magnetic fluxes in the reluctance motor 10D, as in Fig. As shown in Figure 10, the magnetic analysis performed confirms that magnetic flux vectors V are concentrated near the outer circumferential surfaces 22a of the rotor teeth 22 on the rotor side 21. Based on the magnetic flux vectors V inside the rotor teeth 22, it can also be assumed that the third spatial harmonic magnetic fluxes propagate through spatial magnetic paths MR in the slots 23, as indicated by the dashed line in Figure 10. Fig. 10 is displayed, and return to the stator teeth 12.

[0060] Therefore, in the reluctance motor 10, each of the induction pole coils 27' is connected to a Fig. 10. The location shown is in each of the slots 23 between adjacent rotor teeth 22, so that third spatial harmonic magnetic fluxes can be effectively coupled with the induction pole coils 27'.

[0061] If the magnetic flux density distribution of the third spatial harmonic magnetic fluxes is displayed in vector representation in the same way in the reluctance motor 10 according to the exemplary embodiment, it can be assumed that the third spatial harmonic magnetic fluxes (magnetic flux vectors V) are represented by all rotor teeth 22 on the rotor side 21 and all induction pole coils 27, as shown in Fig. 11 shown, can be coupled. In addition, it can be assumed that all stator teeth 12 are also used as magnetic paths on the stator side 11, so that the third spatial harmonic magnetic fluxes can be coupled to the rotor side 21 through the distributed magnetic paths.

[0062] In this way, the third spatial harmonic magnetic fluxes are not located near magnetic saturation, and the coupling of the third spatial harmonic magnetic fluxes by the air gap G can be prevented. Thus, the third spatial harmonic magnetic fluxes can be more strongly coupled to the induction pole coils 27 to generate a greater capacity of induced currents.

[0063] If the magnetic resistance of the induction pole coils 27 with the environment is low, high magnetic fluxes flow into the rotor teeth 22, for example, to lower the salient pole ratio and thus significantly reduce the reluctance torque. When the high magnetic fluxes flow into the rotor teeth 22, the torque can additionally act in a negative direction (reverse rotation), or magnetic interference can occur to reduce the torque, depending on the relative positional relationship between the stator 11 and the rotor 21.

[0064] Therefore, the induction pole coils 27 are arranged between the rotor teeth 22 and in the slots 23, which are made magnetically independent by a distance or a non-magnetic substance, such as aluminium or resin, in order to avoid disadvantages caused by a magnetic connection between the induction pole coils 27 and the rotor teeth 22.

[0065] From this fact, it is assumed that the reluctance motor 10 can generate induced currents and dissipate energy loss in the induction pole coils 27 more efficiently than the reluctance motor 10D, as shown in Fig. Figure 12 shows that it can collect. It is assumed that, due to the induced currents, the reluctance motor 10 is more improved with respect to a torque characteristic than the reluctance motor 10D, as shown in Figure 12. Fig. 13 shown. According to the in Fig. The torque characteristic shown in Figure 13 can be improved to give the reluctance motor 10 a constant torque approximately 19.5% greater than that of the reluctance motor 10D, while the torque ripple of the reluctance motor 10 can be reduced more than that of the reluctance motor 10D.

[0066] For example, if reluctance motor 10 and reluctance motor 10B with the same stator structure are driven under the same drive conditions (rotational speed, current value, and current phase angle), reluctance motor 10 can be improved to exhibit a constant torque approximately 57.5% greater than reluctance motor 10B, while the torque ripple of reluctance motor 10 can be reduced to approximately 49.8% less than that of reluctance motor 10B. Consequently, in reluctance motor 10, the magnetic vibration of the stator caused by the torque ripple (e.g., a vibration in the reluctance motor) can be reduced. Fig. 14 vibration operating mode shown) can also be reduced, so that the electromagnetic vibration and electromagnetic noise in the motor can also be reduced.

[0067] The reluctance motor 10 is constructed such that it has a structure in which the ratio of the number P of salient poles (rotor teeth 22) on the rotor side 21 to the number S of slots 13 on the stator side 11 corresponds to a ratio of 2:3, as a structure that mainly utilizes spatial harmonic magnetic fluxes of the 3fth order (f = 1, 2, 3 ...). For example, the third spatial harmonic magnetic fluxes are pulsed in a shorter cycle because the frequency of the third spatial harmonic magnetic fluxes is higher than the fundamental frequency input into the drive coils 14. Therefore, the magnetic fluxes coupled to the induction pole coils 27 between the rotor teeth 22 change with respect to their strength, so that the rotor 21 can efficiently generate induced currents.Thus, the rotor 21 can rotate due to the energy loss efficiently collected from the spatial harmonics that are efficiently superimposed on the magnetic flux of the fundamental frequency.

[0068] The reason why P / S = 2 / 3 is used as the ratio of the number P of salient poles of the rotor teeth to the number S of stator slots in the reluctance motor 10 with respect to the structure to determine the quality of the relative magnetic action between the rotor side 21 and the stator side 11 is that electromagnetic vibration can be reduced and rotation with low electromagnetic noise can be achieved.

[0069] Specifically, according to the magnetic field analysis, which is applied to the magnetic flux density distribution in the same manner as described above, the magnetic flux density distribution within a mechanical angle of 360° is also distributed circumferentially according to the ratio of the number P of salient poles of the rotor teeth to the number S of stator slots. Therefore, an unequal distribution with respect to the distribution of an electromagnetic force acting on the stator 11 is also observed.

[0070] Therefore, for example, in an 8P9S structure with a combination of eight salient poles of rotor teeth and nine stator slots, an uneven magnetic flux density distribution can form, which is unequal circumferentially within the mechanical angle of 360°, so that an inequality can also occur with respect to the distribution of an electromagnetic force acting on the stator 11, and high electromagnetic vibration can occur. In a 14P12S structure, additionally high and low regions are formed due to a mutual rotational symmetry in the magnetic flux density distribution. As in Fig. As shown in Figure 14, high electromagnetic vibration can occur in a vibration operating mode of k = 0, in which radial contraction and expansion without rotation in the vibration direction are repeated in the reluctance motor, which can thus be deformed elliptically. If the electromagnetic vibration occurs in this manner, high electromagnetic noise can consequently occur.

[0071] Furthermore, in a 16P18S structure, some regions where the magnetic fluxes cannot be coupled can be formed circumferentially within the mechanical angle of 360°, resulting in a reduction of the accumulated energy. Additionally, in the 16P18S structure, the combined waveform of the induced currents generated in the induction pole coils exhibits a waveform similar to that in Fig. 7 corresponds, also a waveform in which noise occurs, as if there were 27A', 27B' on each induction pole coil, as in Fig. As shown in 15, this would occur. Therefore, rotor 21 cannot be rotated stably.

[0072] On the other hand, the reluctance motor 10 uses an 8P12S (P / S = 2 / 3) structure with a combination of eight salient poles of rotor teeth and twelve stator slots. Thus, the magnetic fluxes can be coupled in a uniform density distribution over the entire circumference within the mechanical angle of 360°, so that the rotor 21 can be rotated with high quality within the stator 11.

[0073] Thus, in the reluctance motor 10, the spatial harmonic magnetic fluxes are not lost but can be used for rotational operation. Additionally, the energy loss can be efficiently collected, thereby significantly reducing electromagnetic vibration, and the reluctance motor 10 can be rotated very quietly.

[0074] Furthermore, as in Fig. Figure 16 shows a magnetic flux with a Fig. The waveform shown in Figure 17 is coupled to each rotor tooth 22 in the reluctance motor 10, which has the (P / S = 2 / 3) structure. When this magnetic flux waveform is subjected to a Fourier series expansion, the magnitude of a third-order component in the spatial harmonic magnetic flux of the 3fth order is shown in Figure 17. Fig. Figure 18 shows the largest component. Accordingly, it is assumed that the third-order component is optimal for generating an induced current in each induction pole coil 27. Furthermore, a representation of coils 27 and 28 is shown in Figure 18. Fig. 16 according to Fig. Items 19 to 21 are not shown, but are described below.

[0075] When the magnetic flux density distribution of the spatial harmonic magnetic fluxes of the 3fth order is displayed in vector representation, it can be assumed that the in Fig. The third spatial harmonic magnetic fluxes shown in Figure 19 can be coupled with a high density, which is at least several times greater than that shown in Figure 19. Fig. 20 shown sixth spatial harmonic magnetic fluxes or those of the in Fig. The ninth spatial harmonic magnetic fluxes shown in Figure 21 are shown.

[0076] Therefore, the structure P / S = 2 / 3 is used in the reluctance motor 10. The in Fig. The spatial harmonic magnetic flux distributions shown in Figures 19 to 21 are generated as vector diagrams in the structure of the reluctance motor 10B, which is the basis of the reluctance motor 10, for comparison purposes.

[0077] Thus, in the reluctance motor 10, electrical energy is not supplied to any source other than the drive coils 14 of the stator 11, but rather induced currents can be efficiently generated in the induction pole coils 27, which are arranged on the rotor side 21, and supplied as field currents to the electromagnetic coils 28, which can serve as self-excitation electromagnets. The reluctance motor 10 therefore receives an auxiliary rotational force to support the primary rotational force generated by the electrical energy supplied to the drive coils 14, enabling the reluctance motor 10 to be rotated with high efficiency.

[0078] According to an operating mode of the exemplary embodiment other than the radial spacer structure in the reluctance motor 10, the reluctance motor 10 can be manufactured to have an axial spacer structure. In this case, the reluctance motor 10 can, for example, be manufactured to have a multi-spacer type structure, as shown in Fig. Figure 22 shows a multi-spaced structure. In this structure, axial stators 31, opposite an axial end surface face of a rotor 21, are formed on the side of a stator 11, and extending drive coils 14' are wound on the axial stators 31. Additionally, a structure is added to the rotor side 21 in which induction pole coils 47, opposite the axial stators 31 on their axial end surface face, are wound on core materials 47a.

[0079] If the reluctance motor is designed to have a flat motor structure with a large diameter, a double-spaced motor structure can be used, in which a rotor is mounted rotating between an inner stator and an outer stator. In the double-spaced motor structure, induction pole coils 67 are arranged on the inner circumferential surface of a rotor 61 facing an inner stator 51 to collect energy losses, and electromagnetic coils 68 are arranged on the outer circumferential surface of the rotor 61 facing an outer stator 71 to generate torque using the collected induced currents as field currents.

[0080] In motors with a radial spacer structure, such as the reluctance motor 10, the stator 11 and the rotor 21 are often manufactured to have a laminated structure of electromagnetic steel sheets. However, the invention is not limited to this. For example, a so-called SMC core can be used. The SMC core is a solid core in which soft magnet compositions, formed from magnetic particles such as iron powder that has undergone a surface treatment with an insulating coating, are further subjected to iron powder compression molding and heat treatment. This SMC core is particularly suitable for the axial spacer structure because it can be easily formed.

[0081] Furthermore, the reluctance motor 10 is not limited to use within a vehicle. The reluctance motor 10 can preferably be used, for example, as a drive source for a wind turbine generator, a machine tool, etc.

[0082] The scope of the invention is not limited to the illustrative embodiment shown in the drawings and the description, but may include all embodiments that produce equivalent effects with respect to any motor to which the invention relates. Furthermore, the scope of the invention is not limited to a combination of features of the invention described in the claims, but may be described according to any desired combination of specific features selected from all disclosed features.

Claims

[1] Reluctance motor (10) comprising: a stator (11) provided with drive coils (14) into which multiphase drive currents are applied; and a rotor (21) provided with a plurality of salient poles which receive a primary rotational force when magnetic fluxes generated in the drive coils (14) are coupled to the rotor (21), wherein the rotor (21) comprises: Induction pole coils (27, 27A, 27B) which are arranged on magnetic paths on which spatial harmonics superimposed on the magnetic fluxes generated in the drive coils (14) are coupled to the rotor side, so that induced currents in the induction pole coils (27, 27A, 27B) can be generated due to the spatial harmonics of the magnetic fluxes; Rectifier elements (29, 29A, 29B) which rectify the induced currents generated in the induction pole coils (27, 27A, 27B); and electromagnetic coils (28, 28A, 28B) to which the induced currents rectified by the rectifier elements (29, 29A, 29B) are directed as field currents, so that the electromagnetic coils (28, 28A, 28B) can be self-excited in order to generate an electromagnetic force as an auxiliary rotational force to support the primary rotational force, wherein the induction pole coils (27, 27A, 27B) are arranged between adjacent salient poles of the rotor (21), wherein core materials (27a) made of a magnetic substance are arranged between adjacent salient poles of the rotor (21), wherein the induction pole coils (27, 27A, 27B) are concentratedly wound on the core material (27a), and wherein the core materials (27a) are fixed on the rotor (21) via a non-magnetic substance. [2] Reluctance motor (10) according to claim 1, wherein the electromagnetic coils (28, 28A, 28B) are wound concentrated on the salient poles. [3] Reluctance motor (10) according to claim 1, wherein a ratio of a number P of the salient poles of the rotor (21) to a number S of slots (13, 23) in which the drive coils (14) of the stator (11) are arranged is set to P / S = 2 / 3.

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