JP2014007837A - Rotary electric machine and system for driving rotary electric machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent entry into capacitors of an electric current of a half-wave component that is opposite in phase to an electric current of a desired half-wave component and that is to be interrupted.SOLUTION: A stator 12 includes stator windings 20u, 20v, and 20w wound around teeth 19. A rotor 14 includes: a rotor core 24; a plurality of rotor windings 28n wound around salient poles 26 of the rotor 14; diodes 38 that allow circumferentially different magnetic characteristics to be produced in the salient poles 26 by induced electromotive force generated in the rotor windings 28n; and capacitors 44 that are connected in parallel with the respective diodes 38. Thyristors 46 as rectifiers are connected in the same forward direction as the diodes 38 in series with the respective capacitors 44.

Description

  The present invention relates to a rotating electrical machine in which a stator and a rotor are arranged to face each other, and a rotating electrical machine drive system including the rotating electrical machine.

  Conventionally, as described in Patent Document 1, a rotating electrical machine in which a stator and a rotor are arranged to face each other, and the rotor is a pair of teeth that are a pair of salient poles provided on the rotor core on the opposite side in the radial direction. And a rotating electrical machine in which a rotor winding is wound around a salient pole of a rotor core is known. In addition, since the rotor winding is short-circuited in one direction by a diode, one of the pair of teeth is excited to the N pole and the other is excited to the S pole. Furthermore, Patent Document 1 discloses, as another example, a configuration in which a capacitor is connected in parallel with a diode for the purpose of stabilizing the excitation current and generated voltage flowing in the rotor winding.

  Patent Document 2 describes a rotating electrical machine in which a rotor winding is wound around a plurality of salient poles of a rotor, and each rotor winding is short-circuited in one direction or in the opposite direction by a diode. The diode performs half-wave rectification on the alternating current induced in the rotor winding, and forms a magnetic pole by alternately exciting circumferentially adjacent salient poles to N and S poles. Also in this configuration, a current smoothing capacitor is connected in parallel with the diode.

JP 2007-185082 A JP 2008-86161 A

  In the configurations described in Patent Documents 1 and 2 above, a diode is connected to the rotor winding wound around the rotor, and the direction in which the diode is short-circuited is regulated, so that the induced electromotive force generated in the rotor winding The magnetic characteristics generated between adjacent salient poles can be made different. However, since a capacitor is connected in parallel with the diode, the half-wave component current that should be blocked out of phase with the desired half-wave component of the alternating current that flows through the rotor winding by the rotating magnetic field of the stator. Flows through the capacitor to the rotor winding. In this case, since the induction current flows through the rotor winding in the direction opposite to the desired direction, the rotating electrical machine cannot be controlled with high responsiveness.

  Further, the inventor is a rotating electric machine in which a capacitor is connected in parallel to a diode as in Patent Document 2, and a rotating magnetic field including a harmonic component is generated in a stator, and a harmonic component of the rotating magnetic field is generated in a rotor winding. Was applied to generate an induced electromotive force, and the magnetic characteristics generated in the plurality of salient poles by the diode were alternately varied in the circumferential direction. In this case, an LC resonance circuit is constituted by the rotor winding and the capacitor. For this reason, the present inventor increases the magnetic force generated in the rotor winding by superimposing the harmonic current on the stator current flowing through the stator and matching the resonance frequency of the harmonic current with the resonance frequency of the LC resonance circuit. I thought it was possible. However, if a capacitor is connected in parallel to the diode, as in the case of Patent Documents 1 and 2, the AC current that flows through the rotor winding has an opposite phase to the desired half-wave component. There is a possibility that the current of the half wave component to be cut off flows into the rotor winding through the capacitor. Also in this case, the rotating electrical machine cannot be controlled with high responsiveness.

  An object of the present invention is to connect a rotor winding wound around each salient pole of a rotor, a diode for alternately changing magnetic characteristics generated in a plurality of salient poles in a circumferential direction, and a diode in parallel in a rotating electric machine. In the configuration including the capacitor, the current of the half-wave component to be blocked out of phase opposite to the desired half-wave component current is prevented from flowing into the capacitor.

  The rotating electrical machine according to the present invention employs the following means in order to achieve the above object.

  A rotating electrical machine according to the present invention includes a stator including a plurality of stator windings that generate a rotating magnetic field, a rotor core, salient poles provided at a plurality of circumferential positions of the rotor core, and wound around each salient pole. A rotor winding, a diode connected to each of the rotor windings, and a diode that alternately changes magnetic characteristics generated in the plurality of salient poles by an induced electromotive force generated in each rotor winding, and in parallel with the diode A rotating electrical machine comprising a rotor connected to the stator and having a rectifier connected in series in the same forward direction as the diode. is there.

  In the rotating electrical machine according to the present invention, preferably, the rectifier is a thyristor.

  In the rotating electrical machine according to the present invention, preferably, the rotor is provided on each salient pole, and is magnetized in the same direction as the magnetization direction of each salient pole that occurs when an induced current flows through each rotor winding. Including a permanent magnet.

  A rotating electrical machine drive system according to the present invention includes the above-described rotating electrical machine according to the present invention and a control device that controls driving of the rotating electrical machine, and the control device includes a stator current flowing through the stator winding. Further, the rotating electrical machine drive system further includes a harmonic superposition unit that superimposes a harmonic current having the same frequency as the LC resonance frequency of the circuit including the rotor winding and the capacitor.

  In the rotating electrical machine drive system according to the present invention, preferably, the harmonic superimposing unit superimposes the harmonic current on the stator current when the rotational speed of the rotor is equal to or lower than a predetermined speed, and rotates the rotor. The superposition of the harmonic current is switched so that the harmonic current is not superimposed on the stator current when the speed exceeds the predetermined speed.

  According to the rotating electrical machine and the rotating electrical machine drive system of the present invention, the capacitor is connected in parallel to the diode that alternately changes the magnetic characteristics generated in the plurality of salient poles in the circumferential direction. Directional rectifiers are connected in series. For this reason, when an alternating current is about to flow through the rotor winding and a half-wave component current having a phase opposite to that of the desired half-wave component is flowing through the capacitor, the rectifier is reversed. Block the phase current from flowing into the capacitor. Therefore, in a configuration including a rotor winding wound around each salient pole of the rotor, a diode that alternately alters magnetic characteristics generated in a plurality of salient poles in the circumferential direction, and a capacitor connected in parallel to the diode, Therefore, it is possible to prevent the half-wave component current that should be blocked in the opposite phase to the half-wave component current from flowing into the capacitor.

In the rotary electric machine of embodiment of this invention, it is a figure which shows schematic structure of the stator and rotor seen in the rotating shaft direction of the rotor. FIG. 2 is a diagram illustrating a schematic configuration of a stator in the rotating electrical machine of FIG. 1. FIG. 2 is a diagram illustrating a schematic configuration of a rotor in the rotating electrical machine of FIG. 1. FIG. 2 is an enlarged view corresponding to part A of FIG. 1, showing a state in which an induced current flows through a rotor winding. FIG. 4 is a diagram showing an LC resonance circuit including a rotor winding and a diode wound around one salient pole of FIG. 3. It is a circuit diagram showing a rotary electric machine drive system of an embodiment of the present invention. It is a figure which shows the stator current of the 1 phase which superimposed the harmonic current in the harmonic superimposition part of a rotary electric machine drive system. It is a figure which shows the harmonic current (harmonic signal) before the rectification by the diode applied to the rotor winding, and the induced current (rotor winding current) after the rectification flowing through the rotor winding. FIG. 2 is an enlarged view corresponding to part A of FIG. 1, showing a state in which no induced current flows through the rotor winding.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, the stator core and the rotor core constituting the rotating electrical machine will be described as being formed by laminating electromagnetic steel plates, but this is an example, and a laminate of plate materials other than the electromagnetic steel plates may be used. . Other stator cores and rotor cores may be used. For example, instead of a laminated type of plate material, an integrated core obtained by processing a steel material or a core formed by compacting magnetic powder may be used. Moreover, each core is good also as a split-type core formed by connecting the some element divided | segmented into the circumferential direction cyclically | annularly.

  The number of teeth of the stator and the number of salient poles of the rotor described below are examples for explanation, and can be changed as appropriate. Further, in the following, the same elements are denoted by the same reference symbols in all the drawings, and redundant description is omitted or simplified.

  FIG. 1 is a diagram showing a schematic configuration of a stator and a rotor as viewed in the direction of the rotation axis of a rotor in a rotating electrical machine according to an embodiment of the present invention used as a motor or a generator.

  The rotating electrical machine 10 includes a stator 12 that is fixed to a casing (not shown), and a rotor 14 that is opposed to the stator 12 in the radial direction with a predetermined gap therebetween and is rotatable with respect to the stator 12. Note that, when simply referred to as “radial direction”, it means a radial direction orthogonal to the rotation center axis of the rotor 14 (the same applies to the entire specification and claims). The rotor 14 is fixed to the rotary shaft 16 and rotates integrally with the rotary shaft 16.

  Further, as shown in FIG. 2, the stator 12 includes a stator core 18, teeth 19 disposed at equally spaced positions in the circumferential direction of the stator core 18, and a plurality of phases wound around each tooth 19 (more specifically, Includes three-phase stator windings 20u, 20v, and 20w. That is, a plurality of teeth 19 projecting radially inward (toward the rotor 14) are arranged on the inner peripheral surface of the stator core 18 at intervals from each other along the circumferential direction of the stator 12. Slots 22 are formed between the teeth 19. The stator core 18 and the plurality of teeth 19 are integrally formed of a magnetic material such as a laminate in which a plurality of magnetic steel plates are laminated.

  The stator windings 20u, 20v, and 20w for each phase are wound around the teeth 19 through the slots 22 in a short concentrated winding manner. As described above, the stator windings 20u, 20v, and 20w are wound around the teeth 19 to form a magnetic pole. Then, by passing a plurality of phases of alternating current through the plurality of stator windings 20u, 20v, and 20w, a plurality of teeth 19 arranged in the circumferential direction are magnetized, and a rotating magnetic field that rotates in the circumferential direction is generated in the stator 12. . That is, the multi-phase stator windings 20 u, 20 v and 20 w generate a rotating magnetic field in the stator 12. The stator winding is not limited to the configuration in which the stator winding is wound around the teeth 19 of the stator 12 as described above. For example, a toroidal winding in which a plurality of stator windings are wound around a plurality of circumferential portions of the annular portion of the stator core 18 can be used to generate a rotating magnetic field in the stator 12.

  The rotating magnetic field formed on the teeth 19 acts on the rotor 14. In the example shown in FIG. 2, one pole pair is configured by three teeth 19 around which three-phase (u-phase, v-phase, and w-phase) stator windings 20u, 20v, and 20w are wound.

  On the other hand, as shown in FIG. 3, the rotor 14 has a rotor core 24 that is a cylindrical rotor yoke and a plurality of circumferentially equidistant positions on the outer peripheral surface of the rotor core 24, facing radially outward (toward the stator 12). ) A salient pole 26 that is a projecting portion provided in a projecting manner, and a plurality of rotor windings 28n and 28s. Note that the term “circumferential direction” simply refers to a direction along a circle drawn around the rotation center axis of the rotor 14 (the same applies to the entire specification and claims). The rotor core 24 and the plurality of salient poles 26 are integrally formed of a magnetic material such as a laminate in which a plurality of magnetic steel plates are laminated. With respect to the circumferential direction of the rotor 14, the first rotor winding 28 n is wound around every other salient pole 26 by concentrated winding, and another salient pole 26 adjacent to the salient pole 26 around which the first rotor winding 28 n is wound. In addition, the second rotor winding 28s is wound around every other salient pole 26 in the circumferential direction in a concentrated manner. A first diode 38 as a magnetic characteristic adjusting unit is connected so as to short-circuit each first rotor winding 28n in one direction, and a magnetic characteristic adjusting unit so as to short-circuit each second rotor winding 28s in the opposite direction. A second diode 40 is connected.

  In such a configuration, the salient pole 26 is magnetized by the rectified current flowing through the first rotor winding 28n and the second rotor winding 28s, and functions as a magnetic pole portion. By passing an alternating current through the stator windings 20u, 20v, and 20w, the stator 12 generates a rotating magnetic field. This rotating magnetic field is not only a magnetic field of the fundamental wave component but also a harmonic component of a higher order than the fundamental wave. Of magnetic fields.

  More specifically, the distribution of magnetomotive force that generates a rotating magnetic field in the stator 12 depends on the arrangement of the stator windings 20u, 20v, and 20w of each phase and the shape of the stator core 18 by the teeth 19 and the slots 22 (basic It does not have a sinusoidal distribution (only of waves), but includes harmonic components. In particular, in the concentrated winding, the stator windings 20u, 20v, 20w of the respective phases do not overlap each other, so that the amplitude level of the harmonic component generated in the magnetomotive force distribution of the stator 12 increases. For example, when the stator windings 20u, 20v, and 20w are three-phase concentrated windings, the amplitude level of a spatial secondary component that is a temporal third-order component of the input electrical frequency increases as a harmonic component. The harmonic components generated in the magnetomotive force due to the arrangement of the stator windings 20u, 20v, 20w and the shape of the stator core 18 are called spatial harmonics.

  When a rotating magnetic field including this spatial harmonic component acts on the rotor 14 from the stator 12, fluctuations in leakage magnetic flux leaking into the space between the salient poles 26 of the rotor 14 occur due to magnetic flux fluctuations in the spatial harmonics. Is sufficiently large, an induced electromotive force is generated in at least one of the rotor windings 28n and 28s (or 28s). In particular, as will be described later, a rotating electrical machine drive system 68 that drives the rotating electrical machine 10 includes a control device 72, and the control device 72 includes a harmonic superimposing unit 80 that superimposes a harmonic current on a stator current. The maximum value of the level increases. Therefore, a spatial harmonic component having substantially the same frequency as this harmonic current is applied to the rotor winding 28n (or 28s).

  When an induced electromotive force is generated in each rotor winding 28n, 28s, a direct current corresponding to the rectification direction of the diodes 38, 40 corresponding to each rotor winding 28n, 28s flows, and the rotor windings 28n, 28s are wound. The mounted salient pole 26 is magnetized. For this reason, the salient pole 26 functions as a magnetic pole portion having a desired polarity. That is, when a magnetic flux generated by the induced current flowing through the rotor windings 28n and 28s flows through the salient pole 26, a magnetomotive force is generated at the salient pole 26, and a magnetic pole is formed. If the magnetomotive force generated in the salient pole 26 by the induced current is referred to as a coil magnetomotive force, the direction of the coil magnetomotive force is determined by the direction of the induced current. This winding magnetomotive force contributes to the improvement of the torque of the rotating electrical machine 10. Further, the direction of the magnetomotive force of the winding is alternately changed with respect to the circumferential direction of the rotor 14 depending on the rectification direction of the corresponding diodes 38 and 40. In the example of FIG. 3, when it is assumed that an induced current flows in each rotor winding 28n, 28s, an N pole is generated at the tip of the salient pole 26 around which the first rotor winding 28n is wound, and the second rotor An S pole is generated at the tip of the salient pole 26 around which the winding 28s is wound. In FIG. 3, the magnetic poles formed at the tips of the salient poles 26 are indicated by N and S on the outer diameter side of the salient poles 26 when it is assumed that an induced current flows through the rotor windings 28 n and 28 s. . In this case, the N pole and the S pole are alternately arranged in the circumferential direction of the rotor 14. As described above, assuming that an induced current flows in each rotor winding 28n, 28s, each diode 38, 40 (FIG. 3) has a plurality of bumps due to the induced electromotive force generated in each rotor winding 28n, 28s. The magnetic characteristics generated in the poles 26 are alternately varied in the circumferential direction.

  Further, as shown in FIG. 3, the width θ of each rotor winding 28n, 28s in the circumferential direction of the rotor 14 is set to be shorter than the width corresponding to 180 ° in terms of the electrical angle of the rotor 14. More preferably, the width θ of each of the rotor windings 28n and 28s in the circumferential direction of the rotor 14 is equal to or substantially equal to a width corresponding to 90 ° in electrical angle of the rotor 14. The width θ of each rotor winding 28n, 28s here can be expressed by the center width of the cross section of each rotor winding 28n, 28s in consideration of the cross-sectional area of each rotor winding 28n, 28s.

  In the rotating electrical machine 10 of this embodiment, the rotor 14 is connected in series to the diode 38 (or 40) connected to the rotor winding 28n (or 28s) provided for each salient pole 26. Element 42 (or 43) is included. FIG. 4 is an enlarged view corresponding to part A of FIG. 1 showing a state in which an induced current flows through the rotor winding.

  Among the plurality of rotor windings 28n, 28s (FIG. 3), the series connection element 42 connected to each rotor winding 28n arranged at every other circumferential direction includes a capacitor 44, as shown in FIG. A thyristor 46 connected in series with the capacitor 44 in the same forward direction as the diode 38 is included. The thyristor 46 is a one-way thyristor that is a rectifier. In the series connection elements 43 (FIG. 3) connected to the other rotor windings 28s arranged every other one, the thyristor 47 (FIG. 5) whose forward direction is opposite to the thyristor 46 is connected to the capacitor 44. This is the same as the case of the serial connection element 42 described above.

  FIG. 5 is a diagram showing an LC resonance circuit including a rotor winding and a diode wound around one salient pole of FIG. As shown in FIG. 5, the thyristors 46 and 47 are pnpn junction semiconductor elements. The cathodes K 1 of the thyristors 46 and 47 are connected to one end of the capacitor 44. The anode A1 of the thyristors 46 and 47 is connected to a connection point Q between the anode A2 of the diodes 38 and 40 and one end of the rotor winding 28n (or 28s). The gates G1 of the thyristors 46 and 47 are also connected to the connection point Q.

  The other end of the capacitor 44 is connected to a connection point R between the cathode K2 of the diodes 38 and 40 and the other end of the rotor winding 28n (or 28s). Each diode 38 and 40 and each series connection element 42 and 43 can be arrange | positioned outside the axial direction end surface of the rotor core 24 of FIG. 3, for example. As described above, the rotor windings 28n and 28s provided for each salient pole 26 (FIG. 3 and the like), the diodes 38 and 40 and the series connection elements 42 and 43 shown in FIG. 52 is formed.

  Further, as shown in FIG. 3, the rotor 14 includes a permanent magnet 48 provided so as to be embedded in each salient pole 26. Each permanent magnet 48 is magnetized in a direction that coincides with the radial direction of the rotor 14. Each permanent magnet 48 is made of ferrite or the like. The plurality of salient poles 26 alternately reverse the magnetization direction of the permanent magnet 48 in the radial direction of the rotor 14 in the rotor circumferential direction.

  For example, as shown in FIG. 4, in the permanent magnet 48 provided on the salient pole 26 whose tip is an N pole by the induced current of the first rotor winding 28n, the magnetization direction is directed from the inside to the outside in the radial direction, and the outside is N It becomes the pole and the inside becomes the S pole. In FIG. 3, in the permanent magnet 48 provided on the salient pole 26 whose tip is the S pole by the induced current of the second rotor winding 28 s, the magnetization direction is directed from the outside in the radial direction to the inside, and the outside is the S pole. The inside is the N pole. In this way, each permanent magnet 48 is magnetized in the same direction as the magnetization direction of each salient pole 26 that is generated when an induced current flows through each rotor winding 28n, 28s.

  Each permanent magnet 48 can be inserted and fixed in the axial direction, for example, in a hole provided so as to penetrate the intermediate portion of each salient pole 26 in the rotor radial direction in the axial direction.

  Such a rotating electrical machine 10 is driven by the rotating electrical machine drive system 68 of FIG. FIG. 6 is a diagram showing a schematic configuration of a rotating electrical machine drive system 68 that drives the rotating electrical machine 10 of FIG. The rotating electrical machine drive system 68 includes the rotating electrical machine 10, an inverter 70 that is a drive unit that drives the rotating electrical machine 10, a control device 72 that controls the inverter 70, and a power storage device 74 that is a power source. To drive.

  The power storage device 74 is provided as a direct current power source and is chargeable / dischargeable, and is constituted by, for example, a secondary battery. The inverter 70 includes U-phase, V-phase, and W-phase arms Au, Av, and Aw. Each phase arm Au, Av, Aw has two switching elements Sw connected in series. The switching element Sw is a transistor, an IGBT, or the like. A diode Di is connected in antiparallel to each switching element Sw. The midpoint of each arm Au, Av, Aw is connected to one end side of the corresponding phase stator windings 20u, 20v, 20w constituting the rotating electrical machine 10. The stator windings 20u, 20v, and 20w have the same phase stator windings 20u (or 20v or 20w) connected in series in each tooth of the stator 12. The other ends of the stator windings 20u, 20v, 20w are connected at a neutral point.

  The positive electrode side and the negative electrode side of the power storage device 74 are respectively connected to the positive electrode side and the negative electrode side of the inverter 70, and a capacitor 76 is connected in parallel to the inverter 70 between the power storage device 74 and the inverter 70. Yes. For example, when the rotating electrical machine of the present invention is used as a drive motor for a vehicle, the control device 72 sets a torque target of the rotating electrical machine 10 according to an acceleration command signal input from an accelerator pedal sensor (not shown) of the vehicle. The switching operation of each switching element Sw is controlled according to the current command value corresponding to the torque target and the like. The control device 72 includes a signal representing a current value detected by a current sensor 78 provided on the stator winding (for example, 20v, 20w) side of at least two phases of the three phases, and a rotation angle detection unit such as a resolver. A signal indicating the rotation angle of the rotor 14 (FIG. 1) of the rotating electrical machine 10 detected by (not shown) is input. The control device 72 includes a microcomputer having a CPU, a memory, and the like, and controls the torque, the rotation speed, and the like of the rotating electrical machine 10 by controlling the switching of the switching element Sw of the inverter 70. The control device 72 can also be configured by a plurality of control devices divided for each function.

  Such a control device 72 converts the DC power from the power storage device 74 into three-phase AC power of u-phase, v-phase, and w-phase by the switching operation of each switching element Sw constituting the inverter 70, and It is possible to supply electric power of a phase corresponding to each phase of the windings 20u, 20v, and 20w. Further, the control device 72 includes a harmonic superimposing unit 80 that superimposes a harmonic current on the stator current flowing through the stator windings 20u, 20v, and 20w, which will be described later. The rotating electrical machine of the present invention can also be used as a generator that generates power by being driven from the outside via a transmission or the like by an axle fixed to the vehicle wheel. Also in that case, the control device 72 controls the switching of the inverter 70 and supplies an alternating current in which a harmonic current is superimposed on the stator windings 20u, 20v, and 20w.

  In addition, the rotating electrical machine drive system 68 of FIG. 6 is used, for example, as a vehicular travel power generation device mounted on a hybrid vehicle, a fuel cell vehicle, an electric vehicle or the like that includes an engine and a travel motor as drive sources. . Further, a DC / DC converter that is a voltage conversion unit may be connected between the power storage device 74 and the inverter 70 so that the voltage of the power storage device 74 can be boosted and supplied to the inverter 70.

  Next, the basic operation of the rotating electrical machine 10 driven by the rotating electrical machine drive system 68 will be described. A rotating magnetic field (fundamental wave component) formed in the stator 12 acts on the rotor 14 by the three-phase alternating current flowing through the three-phase stator windings 20u, 20v, and 20w, and the magnetism of the rotor 14 is accordingly changed. The salient poles 26 are attracted to the teeth 19 of the stator 12 so as to reduce the resistance. As a result, torque (reluctance torque) acts on the rotor 14.

  Further, when the rotating magnetic field including the spatial harmonics formed on the stator 12 is linked to the rotor windings 28n and 28s of the rotor 14, the rotor windings 28n and 28s have the rotor 14 caused by the spatial harmonics. An induced electromotive force is generated in each of the rotor windings 28n and 28s due to a magnetic flux fluctuation having a frequency different from the rotation frequency (the fundamental wave component of the rotating magnetic field). The current flowing through the rotor windings 28n and 28s accompanying the generation of the induced electromotive force is rectified by the diodes 38 and 40 to be unidirectional. Each salient pole 26 is magnetized in response to the current rectified by each diode 38, 40 flowing through each rotor winding 28n, 28s, and each salient pole 26 has a magnetic pole (either N pole or S pole). On the other hand, it functions as a fixed magnet. In this case, assuming that an induced current flows through each of the rotor windings 28n and 28s, N poles in the circumferential direction as magnetic poles due to the winding magnetomotive force of each salient pole 26 due to the difference in the rectification direction of the diodes 38 and 40. And S poles are alternately arranged.

  Then, the magnetic field of each salient pole 26 (magnet with a fixed magnetic pole) interacts with the rotating magnetic field (fundamental wave component) generated by the stator 12, thereby generating an attractive action and a repulsive action. Torque (torque corresponding to magnet torque) is also applied to the rotor 14 by electromagnetic interaction (attraction and repulsion) between the rotating magnetic field (fundamental wave component) generated by the stator 12 and the magnetic field of the salient pole 26 (magnet). The rotor 14 is rotationally driven in synchronization with the rotating magnetic field (fundamental wave component) generated by the stator 12. As described above, the rotating electrical machine 10 can function as an electric motor that generates power (mechanical power) in the rotor 14 by using power supplied to the stator windings 20u, 20v, and 20w.

  Further, the control device 72 has a harmonic superimposing unit 80. The harmonic superimposing unit 80 superimposes a harmonic current having the same frequency as the LC resonance frequency of the LC resonance circuits 50 and 52 (FIG. 5) on the stator current of each phase flowing through the stator winding. FIG. 7 shows a one-phase stator current in which a harmonic current is superimposed by the harmonic superposition unit 80 of the rotating electrical machine drive system 68 (FIG. 6). A harmonic current is superimposed on the stator current of each phase at a constant period, and this harmonic current is a carrier signal having a carrier frequency. The carrier signal is the same as that used when controlling the switching of the inverter 70 (FIG. 6). A harmonic signal different from the carrier signal can also be used as the harmonic current. The rotating magnetic field generated by the stator 12 by flowing the stator current on which the harmonic current is superimposed on the stator windings 20u, 20v, and 20w of each phase causes a high-level harmonic component having a frequency different from that of the fundamental wave. To include spatial harmonics.

  An induced electromotive force is generated by applying spatial harmonics to the rotor windings 28n and 28s, and an N pole or an S pole is formed at the tip of the salient pole 26. Particularly, since the harmonic current has the same frequency as the LC resonance frequency of the LC resonance circuits 50 and 52, the magnetic force generated in the salient pole 26 by the induced electromotive force can be increased. However, as described in FIG. 5, the capacitor 44 is connected in parallel to the diodes 38 and 40. Therefore, if no special consideration is given, a desired half-wave component for forming a magnetic pole of a desired polarity on each salient pole 26 out of the alternating current that flows through the rotor windings 28n and 28s by the induced electromotive force. There is a possibility that a current of a half wave component to be cut off having a phase opposite to that of the current flows through the capacitor 44 to the rotor windings 28n and 28s.

  On the other hand, in the present embodiment, the capacitor 44 is connected in parallel to the diodes 38 and 40, but thyristors 46 and 47 having the same forward direction as the diodes 38 and 40 are connected in series to the capacitor 44. ing. For this reason, when an alternating current tends to flow through the rotor windings 28n and 28s, and a half-wave component current having a phase opposite to that of the desired half-wave component of the alternating current flows through the capacitor 44, the thyristor 46 is used. , 47 prevent this antiphase current from flowing into the capacitor 44. Therefore, it is possible to prevent a half-wave component current that should be blocked in a phase opposite to that of the desired half-wave component current from flowing into the capacitor 44. As a result, the rotating electrical machine 10 can be controlled with high responsiveness by preventing current from flowing through the capacitor 44 to the rotor windings 28n and 28s in the direction opposite to the direction of rectification by the diodes 38 and 40.

  Moreover, also when making the rotary electric machine 10 function as a generator, the harmonic superimposition part 80 of the control apparatus 72 superimposes a harmonic current on the stator current of each phase. Then, when the rotating shaft 16 with the rotor 14 (FIG. 1) fixed is rotated from the outside, a voltage is induced in the stator windings 20u, 20v, 20w to generate electric power, and the generated electric power is charged in the power storage device 74. For example, when the rotating electrical machine of the present invention is used as a motor generator having the functions of both a drive motor and a generator of a vehicle, ground resistance is applied to a wheel (not shown) during braking, and the power of the axle on which the wheel is fixed is increased. It is transmitted to the rotating shaft 16 via a transmission or the like. In this case, the rotating electrical machine 10 is driven from the outside, and regenerative electric power is generated in the stator 12, and at the same time, the braking force of the vehicle is obtained. Also in this case, by making the frequency of the harmonic current applied to the rotor windings 28n and 28s the same as the resonance frequency of the LC resonance circuits 50 and 52 including the rotor windings 28n and 28s, Magnetic force due to induced electromotive force can be increased. For this reason, large regenerative electric power can be obtained by the rotating electrical machine 10 (FIG. 6), and the power storage device 74 can be charged.

  In addition, since the harmonic component included in the rotating magnetic field generated by the stator 12 has a frequency that matches the LC resonance frequency, it is possible to magnetize the salient pole 26 by continuously flowing an induced current through the rotor windings 28n and 28s. In this case, “continuously” means that the rotor windings 28n and 28s are intermittently positive (upper side in FIG. 8) or negative (lower side in FIG. 8) as shown in the lower side of FIG. It means that the induction current continues to flow only in one of them (the same applies in the following description). FIG. 8 shows the harmonic current (harmonic signal) before rectification by the diodes 38 and 40 applied to the rotor windings 28n and 28s on the upper side, and after rectification flowing through the rotor windings 28n and 28s on the lower side. Inductive current (rotor winding current) is shown. In this case, since the diodes 38 and 40 are provided, the induced current is generated in the rotor windings 28n and 28s only in the direction in which the magnetomotive force is generated in the same direction as the magnetization direction of the permanent magnet 48 disposed on each salient pole 26. Flows.

  Further, as shown in FIG. 5, when a current flows through the diodes 38 and 40 in the forward direction (the direction of the arrow α in FIG. 5), the potential on the anode A2 side of the diodes 38 and 40 rises. The potential on the G1 side also rises and the thyristors 46 and 47 are turned on. For this reason, a current flows through the capacitor 44. Further, the rotor winding 28n will be described. As shown in FIG. 4, the magnetic flux in the arrow γ direction is generated in the salient pole by the induced current flowing in the rotor winding 28n in the arrow β direction, and the same direction as the magnetization direction of the permanent magnet 48. The salient pole 26 is magnetized in the direction. For example, when the salient pole 26 with the N pole formed at the tip and the tooth 19 with the S pole facing each other, the motor torque can be increased or the regenerative power can be increased by attracting each other. Moreover, the magnetic flux of the permanent magnet 48 provided on the salient pole 26 also contributes to increase the motor torque and regenerative power. This state corresponds to the ta time in FIG.

  On the other hand, as shown in FIG. 5, when a current flows through the capacitor 44 in the direction opposite to the forward direction of the diodes 38 and 40 (the direction opposite to the arrow α direction in FIG. 5), the potential on the anode A2 side is Since it remains low, thyristors 46 and 47 are turned off. For this reason, the thyristors 46 and 47 can prevent the half-wave component having the opposite phase to the desired half-wave component from flowing into the capacitor 44. For this reason, for example, the withstand voltage can be secured even with a capacitor 44 having a carrier frequency of 100 kHz and a small capacity of about 1000 pF. Further, the rotor winding 28n will be described. As shown in FIG. 9, if no induced current flows through the rotor winding 28n, the magnetic flux of the permanent magnet 48 loops in the salient pole 26 depending on the magnetic force of the permanent magnet 48. The stator 12 is not affected. In this case, neither the N pole nor the S pole is generated at the tip of the salient pole 26. This state corresponds to the time tb in FIG.

  In addition, since the rotor winding 28n constitutes the LC resonance circuit 50 together with the capacitor 44, an electric current continuously flows through the rotor winding 28n. However, as shown in FIG. The rotor winding 28n is energized only in the same direction as the forward direction (the arrow β direction in FIG. 4). That is, only the same polarity as the magnetic pole on the tip side (upper side in FIG. 4) of the permanent magnet 48 appears at the tip of the salient pole 26 of the rotor 14. For example, in FIG. 4, the tip of the salient pole 26 is an N pole. Therefore, by repeating the states of FIGS. 4 and 9, an induction current (rotor winding current) flows through the rotor winding 28 n continuously as shown in FIG. 8. This effect is obtained by providing the diodes 38 and 40 and the rectifier in the LC resonance circuits 50 and 52 including the rotor windings 28n and 28s and the capacitor 44. When the rotor 14 is rotated from the outside in this state, the stator 12 side generates power and regenerates the power. The salient pole 26 around which the rotor winding 28n is wound has been described above, but the same applies to the salient pole 26 around which another rotor winding 28s (FIG. 3) is wound. As described above, even when the rotary electric machine 10 is used as a generator, by using the thyristors 46 and 47, a half-wave component current that should be cut off in phase opposite to the desired half-wave component current flows into the capacitor 44. Can be prevented.

  As described above, the rotor 14 includes the permanent magnets 48 that are provided on the respective salient poles 26 and are magnetized in the same direction as the magnetization direction of each salient pole 26 that is generated when an induced current flows through each of the rotor windings 28n and 28s. Both the motor torque and the regenerative power can be increased. The permanent magnets 48 can be omitted from the salient poles 26 of the rotor 14.

  Moreover, since the control apparatus 72 has the harmonic superimposition part 80 which superimposes the harmonic current which has the same frequency as the LC resonance frequency of the LC resonance circuits 50 and 52 on the stator current, the magnetic force of each salient pole 26 is further increased. The motor torque and regenerative power can both be increased.

  Further, since the thyristors 46 and 47 are used as rectifiers connected to the capacitor 44, the thyristors 46 and 47 can easily secure the required breakdown voltage with the serial connection elements 42 and 43 including the capacitor 44 and the thyristors 46 and 47. The capacitor 44 having a low withstand voltage can be used. For example, as described in Patent Documents 1 and 2, half-wave rectification using a diode and a rotor winding is waveform-shaped with a capacitor connected in parallel to the diode, and in a configuration that does not use a thyristor, the capacitance of the capacitor is considerably increased. There is a need to. For example, when a harmonic current having a carrier frequency of about 10 kHz is superimposed on the stator current, a capacitor having a large capacity of 1000 μF or more is required for waveform shaping. In this case, it is conceivable to use an electrolytic capacitor having polarity and low withstand voltage, or to connect a considerable number of ceramic capacitors in parallel, but it is difficult to realize any configuration. On the other hand, when the thyristors 46 and 47 are used as in the present embodiment, the turn-on time until the thyristors 46 and 47 are turned on can be used, and a high surge voltage can be suppressed from being applied to the capacitor 44. . For this reason, the capacity | capacitance of the capacitor | condenser 44 can be made small as mentioned above.

  In the above description, the unidirectional thyristor is used as a rectifier connected in series with the capacitor 44. However, a triac, which is a bidirectional thyristor, can be used instead of the one-way thyristor. For example, a triac gate can be connected between the rotor winding and capacitor connection and the diode cathode. In addition, a diode can be used instead of the thyristor. However, in this case, unlike the case of using a thyristor, the turn-on time cannot be used.

  As another example of the present embodiment, in the above-described embodiment, the harmonic superimposing unit 80 included in the control device 72 converts the harmonic current into the stator current when the rotational speed of the rotor 14 is equal to or lower than a predetermined speed. It is also possible to adopt a configuration in which the superposition of the harmonic current is switched so that the harmonic current is not superposed on the stator current when the rotation speed of the rotor 14 exceeds a predetermined speed. According to this configuration, since the harmonic current is not always superimposed on the stator current when the rotational speed of the rotor 14 exceeds a predetermined speed, the same state as that shown in FIG. 7 is continued. In this case, no induced current is generated in the rotor windings 28n and 28s, and the magnetic flux generated by the permanent magnet 48 in the salient pole 26 loops in the salient pole 26. For this reason, neither the N pole nor the S pole is generated at the tip of the salient pole 26. Therefore, the influence of the magnetic force of the salient pole 26 on the stator 12 can be suppressed regardless of whether the polarity of the teeth 19 of the stator 12 facing the salient pole 26 is N or S. In general, it is known that when the magnetic force of the salient pole 26 reaches the stator 12 during high-speed rotation of the rotor 14, drag loss of the rotating electrical machine 10 increases due to generation of a counter electromotive voltage. On the other hand, according to the configuration of the other example described above, drag loss at the time of high speed rotation of the rotating electrical machine 10 can be suppressed, and torque reduction can be suppressed.

  As mentioned above, although the form for implementing this invention was demonstrated, this invention is not limited to such embodiment at all, and it can implement with a various form in the range which does not deviate from the summary of this invention. Of course. For example, in the above description, the case where the rotor is disposed opposite to the inner side in the radial direction of the stator has been described. Further, a so-called radial type rotating electrical machine in which the stator and the rotor are arranged to face each other in the radial direction has been described. However, the present invention can also be implemented in a so-called axial type rotating electrical machine in which the stator and the rotor are arranged to face each other in the axial direction.

  In addition, the case where the stator winding is wound on the stator by concentrated winding has been described, but for example, if the stator can generate a rotating magnetic field including spatial harmonics, the stator winding may be wound on the stator by distributed winding. The present invention can be implemented.

  10 Rotating machine, 12 Stator, 14 Rotor, 16 Rotating shaft, 18 Stator core, 19 Teeth, 20u, 20v, 20w Stator winding, 22 Slot, 24 Rotor core, 26 Salient pole, 28n First rotor winding, 28s Second rotor Winding, 38 First diode, 40 Second diode, 42, 43 Series connection element, 44 Capacitor, 46, 47 Thyristor, 48 Permanent magnet, 50, 52 LC resonance circuit, 68 Rotating electric machine drive system, 70 Inverter, 72 Control Device, 74 power storage device, 76 capacitor, 78 current sensor, 80 harmonic superimposing unit.

Claims (5)

A stator including a multi-phase stator winding that generates a rotating magnetic field;
A rotor core; salient poles provided at a plurality of locations in the circumferential direction of the rotor core; rotor windings wound around the salient poles; and induction induction generated in the rotor windings connected to the rotor windings. A diode that alternately changes magnetic characteristics generated in the plurality of salient poles by electric power in the circumferential direction, a capacitor that is connected in parallel to the diode, and a rotor that is disposed to face the stator;
A rotating electric machine characterized in that a rectifier is connected in series to the capacitor in the same forward direction as the diode. In the rotating electrical machine according to claim 1,
The rotating machine is characterized in that the rectifier is a thyristor. In the rotating electrical machine according to claim 1 or 2,
The rotor includes a permanent magnet that is provided on each salient pole and is magnetized in the same direction as the magnetization direction of each salient pole that is generated when an induced current flows through each rotor winding. . The rotating electrical machine according to any one of claims 1 to 3,
A control device for controlling the driving of the rotating electrical machine,
The control device includes a harmonic superimposing unit that superimposes a harmonic current having the same frequency as the LC resonance frequency of a circuit including the rotor winding and the capacitor on the stator current flowing in the stator winding. A rotating electric machine drive system that is characterized. In the rotating electrical machine drive system according to claim 4,
The harmonic superimposing unit superimposes the harmonic current on the stator current when the rotation speed of the rotor is equal to or lower than a predetermined speed, and adds the harmonic current to the stator current when the rotation speed of the rotor exceeds the predetermined speed. A rotating electrical machine drive system, wherein the superposition of the harmonic current is switched so that the wave current is not superposed.

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