WO2022064547A1

WO2022064547A1 - Rotor and rotating electric machine

Info

Publication number: WO2022064547A1
Application number: PCT/JP2020/035683
Authority: WO
Inventors: 貴裕水田; 一将伊藤; 義浩深山
Original assignee: 三菱電機株式会社
Priority date: 2020-09-23
Filing date: 2020-09-23
Publication date: 2022-03-31

Abstract

Provided is a rotating electric machine having a small torque pulsation during start-up and also having high power factor and efficiency during synchronous rotation.　This rotor (3) comprises: a rotor core (7) having a plurality of salient poles (8) projecting outside in the radial direction; a plurality of induction coils (71) for generating induction current; a field coil (72) for generating a field magnetic flux by field current obtained by rectifying the induction current; and a plurality of conductor bars (74) passing through the rotor core in the axial direction. The salient poles are constituted by a base (81) around which the field coil is wound and a plurality of branch portions (82) branching from the base toward the outside in the radial direction. The plurality of induction coils are each wound around at least two branch portions.

Description

Rotor and rotating machine

This application relates to a rotor and a rotary electric machine.

Induction motors that are directly driven by a commercial AC power supply are generally used in cooling water circulation pumps in factories, cooling fans for air conditioning equipment, and the like. Due to the growing awareness of energy conservation in recent years, further improvement in efficiency of induction motors is required. Since the induction motor is a rotary electric machine that generates an induced current in the rotor to obtain an induced torque, there is a limit to high efficiency due to the loss of the induced current.
As a rotary electric machine that copes with such a problem, a rotor core in which a plurality of salient poles are formed at regular intervals in the circumferential direction, an induction coil and a field coil wound around the plurality of salient poles, respectively, and a circumferential direction. Disclosed is a rotary electric machine provided with a rotor having a commutating pole member made of a magnetic material arranged between adjacent salient poles (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-121108

In the conventional rotary electric machine, there is a problem that the torque pulsation at the time of starting due to the reluctance torque is large and the starting becomes difficult because the salient pole ratio is large. Further, since the position of the induction coil is not a position where it efficiently interlinks with the magnetic flux of the space harmonic, only a small field magnetic flux can be obtained, and there is a problem that the power factor and efficiency at the time of synchronous rotation are low.

The present application has been made to solve the above-mentioned problems, and an object thereof is to provide a rotary electric machine having a small torque pulsation at the start and a high power factor and efficiency at the time of synchronous rotation.

The rotor of the rotary electric machine of the present application has a rotor core having a plurality of salient poles protruding outward in the radial direction, a plurality of induction coils for generating an induced current, and a field for rectifying the induced current generated by the induced coil. It is equipped with a rectifying circuit that outputs a magnetic current, a field coil that generates a field magnetic current with a field current, and a plurality of conductor bars that penetrate the rotor core in the axial direction. The salient pole is composed of a base around which the field coil is wound and a plurality of branch portions branched outward in the radial direction from the base, and the plurality of induction coils are formed in at least two branch portions. Each is rolled.

In the rotor of the rotary electric machine of the present application, the salient pole is composed of a base around which a field coil is wound and a plurality of branch portions branched outward in the radial direction from this base, and a plurality of induction coils are formed. It is wound around at least two branches, respectively. Therefore, a rotary electric machine having a small torque pulsation at the start and a high power factor and efficiency at the time of synchronous rotation can be obtained.

It is sectional drawing of the rotary electric machine which concerns on Embodiment 1. FIG. It is a vertical sectional view of the rotary electric machine which concerns on Embodiment 1. FIG. It is sectional drawing of the rotary electric machine of the comparative example which concerns on Embodiment 1. FIG. It is a figure which shows the flow of the d-axis magnetic flux and the flow of the q-axis magnetic flux in the rotary electric machine of the comparative example which concerns on Embodiment 1. FIG. It is a figure which shows the flow of the d-axis magnetic flux and the flow of the q-axis magnetic flux in the rotary electric machine which concerns on Embodiment 1. FIG. It is a figure which shows the torque waveform at the time of starting in the rotary electric machine of the comparative example which concerns on Embodiment 1. FIG. It is a figure which shows the torque waveform at the time of starting in the rotary electric machine which concerns on Embodiment 1. FIG. It is a figure which shows the rotation speed at the time of starting in the rotary electric machine which concerns on Embodiment 1. FIG. It is a figure which shows the flow of the magnetic flux of the space harmonic in the rotary electric machine of the comparative example which concerns on Embodiment 1. FIG. It is a figure which shows the flow of the magnetic flux of the space harmonic in the rotary electric machine which concerns on Embodiment 1. FIG. It is a circuit diagram in the rotary electric machine which concerns on Embodiment 1. FIG. It is a figure which showed the winding direction of the induction coil in the rotary electric machine which concerns on Embodiment 1. FIG. It is a circuit diagram in the rotary electric machine which concerns on Embodiment 1. FIG. It is a figure which shows the connection of the conductor bar in the rotary electric machine which concerns on Embodiment 2. FIG. It is a figure which shows the connection of the conductor bar in the rotary electric machine which concerns on Embodiment 2. FIG. It is a figure which shows the connection of the conductor bar in the rotary electric machine which concerns on Embodiment 2. FIG. It is sectional drawing of the rotary electric machine which concerns on Embodiment 3. FIG. It is a figure which shows the flow of the d-axis magnetic flux and the flow of the q-axis magnetic flux in the rotary electric machine which concerns on Embodiment 3. FIG. It is a figure which shows the flow of the magnetic flux of the space harmonic in the rotary electric machine which concerns on Embodiment 3. FIG. It is a figure which shows the connection of the conductor bar in the rotary electric machine which concerns on Embodiment 3. FIG.

Hereinafter, the rotary electric machine according to the embodiment for carrying out the present application will be described in detail with reference to the drawings. In each figure, the same reference numerals indicate the same or corresponding parts.

Embodiment 1.
FIG. 1 is a cross-sectional view of the rotary electric machine according to the first embodiment. FIG. 1 is a radial cross-sectional view of a rotary electric machine. The rotary electric machine 1 of the present embodiment is composed of a stator 2 and a rotor 3. The stator 2 has a cylindrical shape surrounding the rotor 3 and is arranged with a radial gap with respect to the rotor 3. The rotor 3 has a columnar shape surrounded by the stator 2 and is rotatably supported by the stator 2.

The stator 2 has a stator coil 4 and a stator core 5. The stator core 5 is made of a magnetic material on which electromagnetic steel sheets are laminated. The stator core 5 has a cylindrical core back 51 and a plurality of teeth 52 protruding inward in the radial direction from the inner peripheral side of the core back 51. The space between the plurality of teeth 52 of the stator core 5 is a space opened inward in the radial direction, and is referred to as a stator slot 53. The stator coil 4 is wound around the teeth 52 using the space of the stator slot 53. The stator coil 4 is wound around, for example, each of the plurality of teeth 52 in a concentrated winding manner.

The rotor 3 has a shaft 6 and a rotor core 7. The rotor core 7 is made of a magnetic material on which electromagnetic steel sheets are laminated. The rotor core 7 is fixed to the shaft 6 by shrink fitting or press fitting. The rotor core 7 has four salient poles 8 protruding outward in the radial direction. Each salient pole 8 is composed of a base 81 and two branch portions 82 branched outward in the radial direction from the base 81. In other words, in the radial cross section, the salient pole 8 has a Y-shape with the base 81 and the two branch portions 82. A field coil 72 to which a field current obtained by rectifying an induced current is energized is wound around each base 81. An induction coil 71 for obtaining an induced current is wound around each branch portion 82. The radial outer end of the branch 82 has a shape that extends in the circumferential direction. A plurality of rotor slots 73 penetrating in the axial direction are provided at the radial outer end of the branch portion 82, and a plurality of conductor bars 74 are inserted into the plurality of rotor slots 73, respectively. The conductor bar 74 is located on the outer peripheral side of the induction coil 71. The material of the conductor bar 74 is preferably a metal such as aluminum or copper.

As shown in FIG. 1, in the rotary electric machine 1 of the present embodiment, the number of stator slots 53 is 6, the number of rotor slots 73 of the rotor 3 is 40, and the number of poles of the rotor 3 is the number of poles. The number of poles 8 is 4, but it is not limited to this.

FIG. 2 is a vertical sectional view of a rotary electric machine according to the present embodiment. FIG. 2 is a sectional view taken along the axis of the rotary electric machine. Short-circuit rings 75 for electrically connecting a plurality of conductor bars 74 are provided at both ends of the rotor core 7 in the axial direction. The short circuit ring 75 may be integrally configured with the conductor bar 74. Further, connection plates 76 are provided at both ends of the induction coil 71 and the field coil 72 in the axial direction, respectively. The connection plate 76 is provided with a rectifying circuit that rectifies the induced current induced by the induction coil 71 and outputs a field current. The field current is applied to the field coil.

Next, the operation and effect of the rotary electric machine of the present embodiment will be described. Therefore, as a comparative example, a rotary electric machine having no two branching portions in which the salient poles are branched outward in the radial direction will be described.
FIG. 3 is a cross-sectional view of a rotary electric machine of a comparative example. FIG. 3 is a sectional view taken along the radial direction of the rotary electric machine. As shown in FIG. 3, the salient pole 8 of the rotary electric machine 1 of the comparative example does not have a branch portion branched into two toward the outside in the radial direction. An induction coil 71 for obtaining an induced current and a field coil 72 to which a field current obtained by rectifying the induced current is energized are wound around each salient pole 8. The radial outer end of the salient pole 8 has a shape that extends in the circumferential direction. A plurality of rotor slots 73 are provided at the radial outer end of the salient pole 8, and a plurality of conductor bars 74 are inserted into the plurality of rotor slots 73, respectively. The conductor bar 74 is located on the outer peripheral side of the induction coil 71. In the rotary electric machine 1 of the comparative example shown in FIG. 3, the configuration of the stator 2 is the same as the configuration of the stator of the rotary electric machine of the present embodiment shown in FIG.

FIG. 4 is a diagram showing a flow of d-axis magnetic flux and a flow of q-axis magnetic flux in a rotary electric machine of a comparative example. In FIG. 4, the broken line shows the flow of the d-axis magnetic flux, and the solid line shows the flow of the q-axis magnetic flux. The d-axis magnetic flux flows inside the rotor core 7 having a large magnetic permeability in the rotor. Therefore, the magnetic resistance to the d-axis magnetic flux in the magnetic circuit becomes small, and the d-axis inductance becomes large. On the other hand, the q-axis magnetic flux mainly flows through a portion of air having a small magnetic permeability. Therefore, the magnetic resistance to the q-axis magnetic flux in the magnetic circuit becomes large, and the q-axis inductance becomes small.

Here, assuming that the reluctance torque is _Tr , the number of pole pairs is p, the d-axis inductance is L _d , the q-axis inductance is L _q , the d-axis current is I _d , and the q-axis current is I _q , the following equation (1) is obtained. It holds.
_Tr = p (L _d −L _q ) I _d I _q (1)
As can be seen from the equation (1), the larger the difference between L _d and L _q , the larger the reluctance torque _Tr . Note that ρ = L _d / L _q is called a salient pole ratio, and in a rotary electric machine having a salient pole as shown in FIG. 4, L _d > L _q is usually satisfied, so ρ> 1. Therefore, the larger the difference between the d-axis inductance L _d and the q-axis inductance L _q , the larger the salient pole ratio ρ.

FIG. 5 is a diagram showing a flow of d-axis magnetic flux and a flow of q-axis magnetic flux in the rotary electric machine of the present embodiment. In FIG. 5, the broken line shows the flow of the d-axis magnetic flux, and the solid line shows the flow of the q-axis magnetic flux. In the rotary electric machine of the present embodiment, the salient pole 8 is branched into two branch portions 82 toward the outside in the radial direction. As shown in FIG. 5, both the d-axis magnetic flux and the q-axis magnetic flux flow inside the rotor core 7 having a large magnetic permeability including the branch portion 82 in the rotor. Therefore, the difference between the magnetic resistance to the d-axis magnetic flux and the magnetic resistance to the q-axis magnetic flux in the magnetic circuit becomes small. As a result, the difference between the d-axis inductance L _d and the q-axis inductance L _q becomes small.

As described above, in the rotary electric machine of the comparative example which does not have two branch portions, the difference between the d-axis inductance L _d and the q-axis inductance L _q is large, so that the reluctance torque _Tr becomes large. On the other hand, in the rotary electric machine of the present embodiment having two branch portions, since the difference between the d-axis inductance L _d and the q-axis inductance L _q is small, the reluctance torque _Tr is small.
When compared in terms of salient pole ratio, the salient pole ratio of the rotary electric machine of the comparative example having no two branch portions is larger than the salient pole ratio of the rotary electric machine of the present embodiment having two branch portions.

FIG. 6 is a diagram showing a torque waveform at the start of the rotary electric machine of the comparative example shown in FIG. In FIG. 6, the horizontal axis is the elapsed time from the start time, and the vertical axis is the torque. Further, in FIG. 6, the induced torque 11 obtained from the conductor bar is shown by a broken line, the total torque 12 which is the total of the induced torque and the reluctance torque is shown by a solid line, and the load torque 13 is shown by a dotted line. Since the rotor is stopped at the start time, torque pulsation due to the reluctance torque of one cycle is generated in the total torque 12 while the electric angle advances by one cycle. When the total torque 12 exceeds the load torque 13, it is possible to start from the stopped state. However, as shown in FIG. 6, in the time zone 14 when the total torque 12 is lower than the load torque 13, the rotor is decelerated and the torque pulsation becomes large. Further, depending on the magnitude of the reluctance torque and the load torque, it may not be possible to accelerate from the stopped state and it may be difficult to start. In the rotary electric machine of the comparative example shown in FIG. 3, since the reluctance torque is large, the torque pulsation of the total torque 12 at the time of starting is large, and the pulsation of the rotational speed is large even when the start is impossible or possible.

FIG. 7 is a diagram showing a torque waveform at the time of starting the rotary electric machine of the present embodiment. In FIG. 7, the horizontal axis is the elapsed time from the start time, and the vertical axis is the torque. Further, in FIG. 7, the induced torque 11 obtained from the conductor bar is shown by a broken line, the total torque 12 which is the total of the induced torque and the reluctance torque is shown by a solid line, and the load torque 13 is shown by a dotted line. In the rotary electric machine of the present embodiment, since the reluctance torque is small, the torque pulsation of the total torque 12 at the time of starting becomes small. Therefore, the time zone 14 in which the total torque 12 is lower than the load torque 13 is shorter than in the case of the comparative example. As a result, the rotary electric machine of the present embodiment is easy to start and the pulsation of the rotation speed is suppressed.

FIG. 8 is a diagram showing the rotation speed at the start of the rotary electric machine according to the present embodiment. In FIG. 8, the horizontal axis is the elapsed time from the start time, and the vertical axis is the rotation speed. Further, in FIG. 8, the solid line shows the rotation speed of the rotary electric machine of the present embodiment, and the broken line shows the rotation speed of the rotary electric machine of the comparative example shown in FIG. Power is input to the rotary electric machine at zero time. When power is applied to the rotary electric machine, the rotation speed increases toward the synchronous rotation speed.

In the rotary electric machine of the comparative example, the torque pulsation is large because the reluctance torque is large. Therefore, the pulsation of the rotation speed generated from the start time to the arrival of the synchronous rotation speed is large. Further, in the rotary electric machine of the comparative example, pulsation occurs in the rotation speed even after reaching the synchronous rotation speed, and the pulsation of this rotation speed causes noise and vibration.

On the other hand, in the rotary electric machine of the present embodiment, the torque pulsation is small because the reluctance torque is small. Therefore, the pulsation of the rotation speed generated from the start time to the arrival of the synchronous rotation speed is smaller than that of the rotary electric machine of the comparative example. Further, in the rotary electric machine of the present embodiment, the pulsation of the rotational speed after reaching the synchronous rotation speed is also smaller than that of the rotary electric machine of the comparative example.

As described above, in the rotary electric machine of the present embodiment, the salient pole of the rotor core has a plurality of branch portions branched outward in the radial direction, and the plurality of induction coils have two branch portions. Since each coil is wound around, the torque pulsation at the time of starting is smaller than that of a rotary electric machine having no branch portion.

FIG. 9 is a diagram showing the flow of magnetic flux of spatial harmonics at a certain time in the rotary electric machine of the comparative example shown in FIG. In FIG. 9, the solid line shows the flow of the magnetic flux of the spatial harmonics. In the rotary electric machine of the comparative example, the number of slots of the stator is 6, and the number of poles of the rotor is 4. In the rotary electric machine of the comparative example, the space harmonic that is mainly interlinked with the induction coil and becomes the field magnetic flux source is the space harmonic of the 8-pole magnetic flux, that is, the secondary space of the 4-pole magnetic flux that is the fundamental wave. It becomes a harmonic. Therefore, in FIG. 9, the flow of the magnetic flux of the spatial harmonic shown by the solid line shows the flow of the magnetic flux of the secondary spatial harmonic. In the rotary electric machine of the comparative example, the magnetic flux of the second spatial harmonic mainly flows through the portion of air having a small magnetic permeability, so that the magnetic resistance becomes large. Therefore, the magnitude of the magnetic flux of the second spatial harmonic is also reduced. Further, the secondary spatial harmonics generated between the adjacent salient poles are at positions where it is difficult to interlink with the induction coil. As a result, in the rotary electric machine of the comparative example, the induced current induced in the induction coil is also small, so that the field magnetic flux obtained by the field coil is also small, and the power factor and efficiency are small.

FIG. 10 is a diagram showing the flow of magnetic flux of spatial harmonics at a certain time in the rotary electric machine of the present embodiment. In FIG. 10, the solid line shows the flow of the magnetic flux of the spatial harmonics. Further, FIG. 10 shows each induction coil wound around each branch portion by A to H, and also shows the winding direction of each induction coil. In the rotary electric machine shown in FIG. 10, the winding direction of the induction coil of each of the four salient poles is the same. In the rotary electric machine of the present embodiment, the spatial harmonic that is mainly interlinked with the induction coil and becomes the field magnetic flux source is the secondary spatial harmonic of the four-pole magnetic flux that is the fundamental wave. Therefore, in FIG. 10, the flow of the magnetic flux of the spatial harmonic shown by the solid line shows the flow of the magnetic flux of the secondary spatial harmonic. In the rotary electric machine of the present embodiment, the magnetic flux of the secondary spatial harmonics mainly flows in the rotor core having a large magnetic permeability including the branch portion, so that the magnetic resistance becomes small. Therefore, the magnitude of the magnetic flux of the second spatial harmonic is also larger than that of the rotary electric machine of the comparative example. Further, since each induction coil A to H is wound around each branch portion, the induction coils A to H are likely to be interlinked with the second spatial harmonic. Therefore, the induced current induced in the induction coil also increases. As a result, in the rotary electric machine of the present embodiment, the field magnetic flux obtained by the field coil is also larger than that of the rotary electric machine of the comparative example, and the power factor and efficiency are increased.

FIG. 11 is a circuit diagram showing the connection of the induction coil, the rectifying circuit, and the field coil in the rotary electric machine of the present embodiment shown in FIG. As shown in FIG. 11, each induction coil A to H constituting the induction coil 71 is connected in series, and the induction coil 71 is connected to the field coil 72 via the rectifying circuit 77. The rectifier circuit 77 is a single-phase bridge type full-wave rectifier circuit composed of four diodes. Since the induced currents generated in the respective induction coils A to H are in phase with each other, the induced currents generated in the induction coils 71 become large. The induced current generated in the induction coil 71 is rectified by the rectifying circuit 77 to become a field current, and this field current is energized in the field coil 72. As a result, in the rotary electric machine of the present embodiment, a large field magnetic flux can be obtained by the field coil 72.

FIG. 12 is a diagram showing the winding direction of the induction coil in another rotary electric machine of the present embodiment. In the rotary electric machine shown in FIG. 10, the winding direction of the induction coil of each of the four salient poles is the same. On the other hand, in the rotary electric machine shown in FIG. 12, the winding directions of the induction coils of the adjacent salient poles are reversed. Specifically, in the rotary electric machine shown in FIG. 12, the winding directions of the induction coils C, D, G and H are reversed with respect to the rotary electric machine shown in FIG. In the rotary electric machine configured in this way, the phases of the induced currents generated by the induction coils A, B, E and F are in phase, and the phases of the induced currents generated in the induction coils C, D, G and H are the same. It becomes the phase. Further, a phase difference of 180 ° is generated between the phase of the induced current generated by the induction coils A, B, E and F and the phase of the induced current generated by the induction coils C, D, G and H.

FIG. 13 is a circuit diagram showing a connection of an induction coil, a rectifying circuit, and a field coil in another rotary electric machine according to the present embodiment shown in FIG. In this rotary electric machine, the induction coils A, B, E and F having the same phase of the induced current and one diode are connected in series, and the induction coils C, D, G and the induction coils having the same phase of the induced current are connected. H and one diode are connected in series. The two diodes are connected so that they face each other in the forward direction, and the rectifier circuit 77 is composed of the two diodes. The series-connected induction coils A, B, E, F and one diode, and the series-connected induction coils C, D, G, H and one diode are connected in parallel to the field coil 72. There is. The induced current generated in the induction coil 71 is rectified by the rectifying circuit 77 to become a field current, and this field current is energized in the field coil 72. As a result, even in the rotary electric machine configured as described above, a large field magnetic flux can be obtained by the field coil 72.
In the circuit shown in FIG. 13, the number of diodes constituting the rectifier circuit 77 can be halved as compared with the circuit shown in FIG.

As described above, in the rotary electric machine of the present embodiment, the salient pole of the rotor core has a plurality of branch portions branched outward in the radial direction, and the plurality of induction coils have two branch portions. Since they are wound around each other, the power factor and efficiency at the time of synchronous rotation are higher than those of a rotary electric machine having no branch portion.

Embodiment 2.
FIG. 14 is a diagram showing the connection of conductor bars in the rotary electric machine according to the second embodiment. The structure of the rotary electric machine of the present embodiment is the same as the structure of the rotary electric machine described in the first embodiment. FIG. 14 shows only the rotor core 7 of the rotor 3, the rotor slot 73, and the conductor bar 74. In FIG. 14, the rotor core 7 is shown by a broken line. In the rotary electric machine of the present embodiment, the number of rotor slots of the rotor is 40, and the number of poles and the number of salient poles 8 are 4. Each salient pole 8 is composed of a base 81 and a plurality of branch portions 82 branched outward in the radial direction from the base 81. In the rotary electric machine of the present embodiment, as shown by the solid line in FIG. 14, all 40 conductor bars 74 are short-circuited and connected by the short-circuit ring 75.

In the rotary electric machine configured in this way, an induced torque is obtained by flowing an induced current from the conductor bar 74 to another conductor bar 74 via the short-circuit ring 75 so as to cancel the four-pole fundamental magnetic flux at the time of starting. Be done. Further, in this rotary electric machine, since the four-pole fundamental magnetic flux is synchronized with the rotor after reaching the synchronous rotation speed, no induced current is generated.
However, the magnetic flux of the 8-pole secondary space harmonic that is interlinked with the induction coil and becomes the field magnetic flux source does not synchronize with the rotor even after reaching the synchronous rotation speed. Therefore, an induced current flows through the conductor bar 74 and the short-circuit ring 75 so as to cancel them. This induced current causes a loss.

FIG. 15 is a diagram showing the connection of conductor bars in another rotary electric machine according to the present embodiment. In this rotary electric machine, as shown by the solid line in FIG. 15, the conductor bar 74 is short-circuited by a short-circuit ring 75 at a pitch that picks up only the quadrupole magnetic flux, that is, at every 90 ° mechanical angle. In other words, in the conductor bars 74 in which 40 conductor bars are arranged in the circumferential direction, the four conductor bars 74 sandwiching the nine conductor bars 74 in the circumferential direction are short-circuited and connected to each other.

In the rotary electric machine configured in this way, an induced current flows through the conductor bar 74 at the time of starting so as to cancel the fundamental wave magnetic flux of four poles. Further, since the interlinkage magnetic flux due to the 8-pole magnetic flux is always 0, no induced current due to the 8-pole magnetic flux is generated in the conductor bar 74 even after reaching the synchronous rotation speed. Therefore, this rotary electric machine has higher efficiency than the rotary electric machine in which all the conductor bars 74 shown in FIG. 14 are short-circuited.
However, since ten electrically isolated short-circuit rings 75 are required, the configuration of the short-circuit ring 75 becomes complicated, the short-circuit ring 75 becomes large, and the entire rotary electric machine becomes large.

FIG. 16 is a diagram showing the connection of conductor bars in another rotary electric machine according to the present embodiment. In this rotary electric machine, as shown by a solid line in FIG. 16, five conductor bars 74 provided in each branch portion 82 are short-circuited and connected. Further, the group of the five conductor bars 74 short-circuited and connected to the branch portion 82 is the group of the five conductor bars 74 short-circuited and connected to another branch portion 82 sandwiching one branch portion 82 in the circumferential direction. It is short-circuited by the short-circuit ring 75.

In the rotary electric machine configured in this way, since the five conductor bars 74 of each branch portion 82 are not connected to the conductor bars 74 of the branch portions 82 on both sides, the interlinkage magnetic flux due to the octapole magnetic flux becomes small. Therefore, the induced current due to the octapole magnetic flux after reaching the synchronous rotation speed becomes small. As a result, the loss due to this induced current is suppressed. Further, since this rotary electric machine can be composed of two electrically isolated short-circuit rings 75, the configuration of the short-circuit ring 75 is simplified as compared with the rotary electric machine shown in FIG.

Embodiment 3.
FIG. 17 is a cross-sectional view of the rotary electric machine according to the third embodiment. FIG. 17 is a sectional view taken along the radial direction of the rotary electric machine. In the rotary electric machine of the present embodiment, the rotor core 7 has four salient poles 8 protruding outward in the radial direction. Each salient pole 8 is composed of a base portion 81 and a branch portion 82 branched into three radially outward from the base portion. A field coil 72 to which a field current obtained by rectifying an induced current is energized is wound around each base 81. Of the three branch portions 82, the induction coil 71 for obtaining an induced current is wound around each of the other two branch portions 82 excluding the central branch portion 82. The radial outer end of the branch 82 has a shape that extends in the circumferential direction. A plurality of rotor slots 73 are provided at the radial outer ends of the branch portion 82, and conductor bars 74 are inserted into the plurality of rotor slots 73, respectively. The conductor bar 74 is located on the outer peripheral side of the induction coil 71. The configuration of the stator 2 of the rotary electric machine of the present embodiment is the same as the configuration of the stator of the rotary electric machine of the first embodiment.

FIG. 18 is a diagram showing a flow of d-axis magnetic flux and a flow of q-axis magnetic flux in the rotary electric machine of the present embodiment. In FIG. 18, the broken line shows the flow of the d-axis magnetic flux, and the solid line shows the flow of the q-axis magnetic flux. In the rotary electric machine of the present embodiment, the salient pole 8 is branched into three branch portions 82 toward the outside in the radial direction. As shown in FIG. 18, since both the d-axis magnetic flux and the q-axis magnetic flux flow inside the rotor core having a large magnetic permeability including the branch portion 82 in the rotor, the magnetic resistance to the d-axis magnetic flux and the q-axis in the magnetic circuit The difference from the magnetic resistance to the magnetic flux becomes small. Therefore, the difference between the d-axis inductance L _d and the q-axis inductance L _q becomes small, and the reluctance torque _Tr becomes small. As a result, the torque pulsation of the rotary electric machine of the present embodiment is suppressed and the start of the rotary electric machine of the present embodiment becomes easy as in the case of the rotary electric machine of the first embodiment.

FIG. 19 is a diagram showing the flow of magnetic flux of spatial harmonics at a certain time in the rotary electric machine of the present embodiment. In FIG. 19, the solid line shows the flow of the magnetic flux of the spatial harmonics. In the rotary electric machine shown in FIG. 19, the winding direction of the induction coil of each of the four salient poles is the same. In the rotary electric machine of the present embodiment, the spatial harmonic that is mainly interlinked with the induction coil and becomes the field magnetic flux source is the secondary spatial harmonic of the four-pole magnetic flux that is the fundamental wave. Therefore, in FIG. 19, the flow of the magnetic flux of the spatial harmonic shown by the solid line shows the flow of the magnetic flux of the secondary spatial harmonic. In the rotary electric machine of the present embodiment, the magnetic flux of the secondary spatial harmonic mainly flows inside the rotor core having a large magnetic permeability including the two branch portions, so that the magnetic resistance becomes small. Further, since each induction coil is wound around each of the two branch portions, the induction coil is likely to be interlinked with this second spatial harmonic. Therefore, the induced current induced in the induction coil also increases. As a result, in the rotary electric machine of the present embodiment, the obtained field magnetic flux is also increased, and the power factor and efficiency are increased.

As described above, in the rotary electric machine of the present embodiment, the salient pole of the rotor core has three branch portions branched outward in the radial direction, and the plurality of induction coils have at least two branches. Since each portion is wound, the torque pulsation at the time of starting is smaller than that of a rotary electric machine having no branch portion, and the power factor and efficiency at the time of synchronous rotation are high.

FIG. 20 is a diagram showing the connection of conductor bars in the rotary electric machine according to the present embodiment. In the rotary electric machine of the present embodiment, as shown by the solid line in FIG. 20, a plurality of conductor bars 74 provided in the respective branch portions 82 are short-circuited and connected. Further, the group of the plurality of conductor bars 74 short-circuited and connected to the branch portion 82 is the group of the plurality of conductor bars 74 short-circuited and connected to another branch portion 82 sandwiching the two branch portions 82 in the circumferential direction. It is short-circuited by the short-circuit ring 75.

In the rotary electric machine configured in this way, since the plurality of conductor bars 74 of each branch portion 82 are not connected to the conductor bars 74 of the branch portions 82 on both sides, the interlinkage magnetic flux due to the octapole magnetic flux becomes small. .. Therefore, the induced current due to the octapole magnetic flux after reaching the synchronous rotation speed becomes small. As a result, the loss due to this induced current is suppressed.

In the rotary electric machine of the present embodiment, the connection of the conductor bar is not limited to the connection shown in FIG. As shown in FIG. 14 of the second embodiment, all the conductor bars may be short-circuited and connected by a short-circuit ring. Alternatively, as shown in FIG. 15 of the second embodiment, conductor bars separated by a pitch of picking up only the quadrupole magnetic flux, that is, at every 90 ° of the mechanical angle may be short-circuited and connected by different short-circuit rings.
Further, in the rotary electric machine of the present embodiment, the induction coil 71 is not wound around the central branch portion 82, but the induction coil 71 may be wound around the central branch portion 82 as well.

In the rotary electric machine of the present embodiment, each salient pole has a branch portion branched into three from the base toward the outside in the radial direction. The number of branching portions may be four or more. In a rotary electric machine having n branches, an induction coil may be wound around at least two of the n branches. Further, in a rotary electric machine in which the number of branch portions is n, a plurality of conductor bars provided in each branch portion are short-circuited, and a group of a plurality of conductor bars short-circuited in the branch portions are connected. A group of a plurality of conductor bars short-circuited and connected to another branch portion having n-1 branch portions sandwiched in the circumferential direction may be short-circuited and connected by a short-circuit ring. In the rotary electric machine to which the conductor bar is connected in this way, the induced current due to the octapole magnetic flux after reaching the synchronous rotation speed becomes small, so that the loss due to this induced current is suppressed.

Although the present application describes various exemplary embodiments and examples, the various features, embodiments, and functions described in one or more embodiments are applications of a particular embodiment. It is not limited to, but can be applied to embodiments alone or in various combinations.
Therefore, innumerable variations not exemplified are envisioned within the scope of the techniques disclosed herein. For example, it is assumed that at least one component is modified, added or omitted, and further, at least one component is extracted and combined with the components of other embodiments.

1 rotor machine, 2 stator, 3 rotor, 4 stator coil, 5 stator core, 6 shaft, 7 rotor core, 8 salient poles, 11 induction torque, 12 total torque, 13 load torque, 51 core back, 52 Teeth, 53 Stator slot, 71 Induction coil, 72 Field coil, 73 Rotor slot, 74 Conductor bar, 75 Short ring, 76 Connection plate, 77 Rectifier circuit, 81 Base, 82 Branch.

Claims

A rotor core with multiple salient poles protruding outward in the radial direction,
With multiple induction coils that generate induced currents,
A rectifier circuit that rectifies the induced current generated by the induction coil and outputs a field current,
A field coil that generates a field magnetic flux with the field current,
A rotor provided with a plurality of conductor bars penetrating the rotor core in the axial direction.
The salient pole is composed of a base around which the field coil is wound and a plurality of branch portions branched outward in the radial direction from the base, and the plurality of induction coils are formed by at least two of the branches. A rotor characterized by being wound around each part.
The rotor according to claim 1, wherein the plurality of induction coils are connected in series with the rectifier circuit.
The rotor according to claim 1 or 2, wherein the plurality of conductor bars are provided at the branch portion radially outside the induction coil.
A plurality of the conductor bars provided in each of the branch portions are short-circuited, and when the number of the branch portions is n, the group of the plurality of conductor bars short-circuited in the branch portion is peripheral. The rotation according to claim 3, wherein the conductor bar is short-circuited and connected to a group of the plurality of conductor bars short-circuited to another branch portion sandwiching the n-1 branch portion in the direction. Child.
The rotor according to any one of claims 1 to 4, wherein the number of branch portions is two or three.
A rotary electric machine comprising the rotor according to any one of claims 1 to 5 and a stator arranged with a gap provided on the outer side in the radial direction of the rotor.
The stator comprises a cylindrical core back, a stator core having a plurality of teeth protruding radially inward from the inner peripheral side of the core back, and a stator coil wound around the teeth. A stator slot, which is a space opened inward in the radial direction, is formed between the plurality of teeth of the stator core, and the stator coil utilizes the space of the stator slot. The rotary electric machine according to claim 6, wherein the teeth are wound in a concentrated winding manner.
The rotary electric machine according to claim 7, wherein the number of salient poles is 4 and the number of stator slots is 6.