JP4619585B2 - Reluctance type rotating electrical machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reluctance type rotating electrical machine in which a permanent magnet is fitted to a rotor.
[0002]
[Prior art]
FIG. 12 is a cross-sectional view of a conventional reluctance type rotating electrical machine. In the figure, an armature 1 is composed of an armature core 2 formed by laminating electromagnetic steel sheets provided with a plurality of slots, and an armature coil 3 housed in the slots and wound around armature teeth 4. It is configured. On the other hand, the rotor 5 whose outer peripheral surface faces the armature teeth 4 does not have a coil for forming a magnetic field, and is composed only of a rotor core 6 with irregularities formed on the outer peripheral portion. For this reason, the reluctance type rotating electrical machine has a simple structure and is inexpensive to manufacture.
[0003]
Here, the principle of output generation of the reluctance type rotating electrical machine will be described. In the reluctance type rotating electric machine, since the outer periphery of the rotor is provided with projections and depressions, the magnetic resistance of the convex portion 12 serving as the magnetic pole is reduced with respect to the magnetic field from the armature core teeth 4, and the magnetic resistance in the concave portion 13 is growing. Therefore, the accompanying magnetic energy stored by passing a current through the armature coil 3 in the gaps between the convex part and the concave part is different. An output is generated by the change in the accompanying magnetic energy.
[0004]
It should be noted that not only the geometrical convex part and concave part are formed on the outer peripheral part of the rotor, but also the magnetic convex part and concave part are arranged so that the magnetic resistance and magnetic flux density distribution varies depending on the circumferential position of the rotor. Can also be formed.
[0005]
Another high-performance rotating electrical machine is a permanent magnet rotating electrical machine. The armature is the same as a reluctance type rotating electric machine, but a surface-arranged type rotating electric machine in which a permanent magnet is arranged on the outer periphery of the rotor core over almost the entire circumference of the rotor, and a permanent magnet in the rotor core. There is an embedded permanent magnet rotating electrical machine.
[0006]
[Problems to be solved by the invention]
Since the reluctance type rotating electric machine has different magnetic resistance at the position of the rotor due to irregularities on the surface of the rotor core, the gap magnetic flux density also changes. Due to this change, the magnetic energy changes and an output is obtained.
[0007]
However, as the current increases, local magnetic saturation increases at the convex portion of the iron core (hereinafter also referred to as the d-axis) that becomes the magnetic pole. As a result, the magnetic flux leaking to the concave portion of the iron core (hereinafter also referred to as the q-axis) between the magnetic poles increases, and the effective magnetic flux passing through the magnetic poles decreases and the output decreases. On the other hand, in terms of magnetic energy, the change in the gap magnetic flux density becomes gentle and the change in the accompanying magnetic energy becomes small due to the leakage magnetic flux generated by the magnetic saturation of the convex portion of the iron core. For this reason, the increase rate of the output with respect to the current decreases, and the output is eventually saturated. Further, the q-axis leakage magnetic flux induces an invalid voltage to lower the power factor.
[0008]
On the other hand, rare earth permanent magnets with a high magnetic energy product are used in permanent magnet rotating electrical machines for miniaturization and high output. Rare earth materials are scarce in resources and are therefore not optimal for general purpose machines that are mass produced. On the other hand, since the ferrite magnet of iron oxide is an abundant resource as a material, it can be supplied stably. However, when a ferrite magnet is applied to the field of a rotating electrical machine, there are two major problems.
[0009]
For one, the magnetic energy product of the ferrite magnet is about 1/10 that of the rare earth magnet, so that the torque generated by the product of the interlinkage magnetic flux and current of the permanent magnet is small, and therefore the output per volume is also small.
[0010]
Another problem is that when the size is reduced and the output is increased, the specific electric load (ampere turn per inner armature length) increases and the coercive force of the ferrite magnet is small. Ferrite magnet is irreversibly demagnetized. In particular, ferrite magnets have a serious problem that they cause irreversible demagnetization at a low temperature of 20 ° C. or less and at a lower demagnetizing field than the above.
[0011]
When variable speed operation is considered, the following problem also occurs. That is, since the magnetic flux of the permanent magnet is constant, the voltage induced in the armature coil increases in proportion to the rotation speed. Therefore, when performing variable speed operation over a wide range up to high-speed rotation, the surface magnet type rotating electrical machine cannot reduce the field magnetic flux, so if the power supply voltage is constantbaseIt is difficult to operate at a constant output more than twice the speed. The embedded permanent magnet rotating electric machine has a smaller interlinkage magnetic flux of the permanent magnet than the surface type permanent magnet rotating electric machine, so that an armature reaction that forms a demagnetizing field opposite to the magnetizing direction of the magnet is applied to the magnet. There is a method for reducing the flux linkage. However, since it is necessary to apply a large demagnetizing field to the permanent magnet, irreversible demagnetization occurs in the ferrite magnet.
[0012]
In addition, during idling, a current is caused to flow through the armature winding for reducing the magnetic flux of the magnet, so that a power loss due to Joule heat occurs and the overall efficiency decreases.
[0013]
The present invention has been made to solve the above problems, and a first object is to provide a reluctance type rotating electric machine that enables variable speed operation over a wide range with a small size, high output and high efficiency without irreversible demagnetization. In offer.
[0014]
Another object of the present invention is to provide a reluctance type rotating electrical machine having high reliability and excellent manufacturability.
[0015]
[Means for Solving the Problems]
  The invention according to claim 1
  In a reluctance type rotating electrical machine comprising an armature having an armature coil and a rotor having a portion having different magnetic resistance in the circumferential direction,
  As a portion having a large magnetic resistance of the rotor, it has a central portion and side end portions extending radially outwardly connected to both sides in the circumferential direction with respect to the central portion,In order to make the side side magnetoresistive smaller than the central magnetoresistive,CentralRadial dimensionA cavity having a smaller circumferential dimension at the side end than
  A ferrite magnet fitted in the center of the cavity and magnetized to cancel the magnetic flux of the armature current through the cavity;
  And the opposite inner side surfaces located on both sides in the circumferential direction of the central portion of the cavity are each formed in a planar shape, and are on the side farther outward in the radial direction compared to the mutual spacing near the center of rotation Are formed to have a slanted surface, and the slanted surface receives a part of the centrifugal force acting on the ferrite magnet during rotation.And
  Further, the side end portions formed continuously on both sides in the circumferential direction of the central portion are formed so as to have an inner surface smoothly continuing on an extension line of the inner surface on the radially outer side of the central portion. In this way, a smooth magnetic path is formed between the peripheral edge of the rotor core and the central portion and the side end portion.It is characterized by that.
[0016]
  The invention according to claim 2 is the reluctance type rotating electric machine according to claim 1, wherein the circumferential direction of the side end portion is the same.Dimensions areIt is characterized by being at least 5 times the air gap length.
[0017]
The invention according to claim 3 is the reluctance type rotating electrical machine according to claim 1 or 2, wherein the ferrite magnet has a radial thickness of 0.3 to 1.0 times based on a circumferential width. It is characterized by that.
[0020]
  The invention according to claim 4 is the invention according to claim 1.In the reluctance type rotating electrical machine, a gap is provided between a radially outer side surface of the ferrite magnet and an inner side surface of the cavity facing the ferrite magnet.
[0021]
  The invention according to claim 5 is the invention according to claims 1 to 4.In the reluctance type rotating electric machine according to any one of the above, the thickness to the side surface on the radially outer side of the cavity is based on the intersection of the center line passing through the middle part of the cavity and the outer periphery of the rotor, up to the side end part. It is characterized by being 0.5 times or more of the circumferential distance.
[0022]
  The invention according to claim 6 is the invention according to claims 1 to 5.In the reluctance type rotating electrical machine described in any one of the items, a concave depression is formed at an intersection between a center line passing through an intermediate portion of the cavity and the outer periphery of the rotor.
[0023]
  The invention according to claim 7 is the invention according to claims 1 to 6.In the permanent magnet type reluctance type rotating electrical machine according to any one of the above, the portion having a small magnetic resistance of the rotor is composed of a magnetic pole having only an iron core, and the circumferential width of the magnetic pole is 0.15 to 0 of the magnetic pole pitch. .35 times.
[0024]
  The invention according to claim 8 is the invention of claims 1 to 7.The permanent magnet type reluctance type rotating electrical machine described in any one of the above items is characterized in that a permanent magnet having higher magnetic energy than a ferrite magnet is fitted to each side end of the cavity.
[0028]
  The invention according to claim 9 is the invention according to claim 8.In the reluctance type rotating electrical machine, the permanent magnet is made of resin and magnet powder.
[0029]
  The invention according to claim 10 is the invention according to claims 1 to 9.In the reluctance type rotating electric machine according to any one of the above, the q-axis magnetic flux linked to the armature winding is operated in a state in which the magnetic flux caused by the current and the magnetic flux caused by the ferrite magnet or the permanent magnet are canceled and become zero at the time of loading. It is characterized by that.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a reluctance type rotating electrical machine according to the present invention. In the figure, an armature 1 is composed of an armature core 2 formed by laminating electromagnetic steel sheets provided with a plurality of slots, and an armature coil 3 housed in each slot. The rotor 5 </ b> A is composed of a rotor core 6 in which electromagnetic steel plates are laminated and a plurality of ferrite magnets 7. In this case, the rotor core 6 is formed with a cavity 8 at each equally divided point obtained by equally dividing the circumferential direction by 2n (n is an integer), for example. The radial dimension of the opposing wall of the central portion 9 in the circumferential direction of the cavity 8 (hereinafter also referred to as depth in consideration of the passage direction of the q-axis armature magnetic flux) is large, and the side end portions on both sides in the circumferential direction of the cavity 8. 10 is formed close to the outer peripheral surface and has a small circumferential dimension (hereinafter also referred to as a depth in consideration of the passage direction of the q-axis armature magnetic flux).
[0031]
FIG. 2 is an enlarged partial sectional view showing the vicinity of the cavity between the magnetic poles of the rotor 5A. In the present embodiment, Cs1 is the depth viewed in the direction of magnetic flux passing through the side edge 10 of the cavity 8 is Csl, the width is Cs2, and the depth of the central portion 9 of the cavity 8 viewed in the direction of magnetic flux passing is Cd. = 6 × Lg, Cs2 = 0.5 × Cd. Here, Lg is the air gap length. Further, a ferrite magnet 7 is fitted in the central portion 9 of the cavity 8, and this ferrite magnet 7 is magnetized so as to cancel the magnetic flux of the armature passing through the portion having a high magnetic resistance. Furthermore, the opposing inner side surfaces 8s located on both sides in the circumferential direction of the central portion 9 of the cavity 8 are each formed in a planar shape, and on the side farther outward in the radial direction as compared to the mutual spacing on the side closer to the rotation center. Are formed so that the distance between them is narrower, and the outer side in the radial direction is tapered so that the ferrite magnet 7 fits into the inclined surface.
[0032]
The anti-demagnetization resistance, torque, permanent magnet retention, variable speed operation and efficiency in the reluctance type rotating electrical machine configured as described above will be described below with reference to FIG.
[0033]
a: Demagnetization resistance
The magnetic pole part iron core 6a existing between the adjacent cavities 8 forms a main magnetic pole having a low magnetic resistance. On the contrary, since the cavity 8 exists between these magnetic poles, the magnetic resistance between these magnetic poles becomes high. It is considered that the q-axis armature magnetic flux with respect to the portion where the cavity 8 is formed is distributed as shown in FIG. That is, since the central portion 9 of the cavity 8 has a large depth, the magnetic resistance is considerably large, and the magnetic resistance of the side end portion 10 of the cavity 8 is smaller than that of the central portion 9. For this reason, the demagnetizing field due to the current is high at the side end 10 of the cavity 8, and the magnetic flux is also concentrated. On the other hand, the demagnetizing field in the ferrite magnet 7 fitted in the central portion 9 of the cavity 8 is reduced. Therefore, irreversible demagnetization does not occur during loading even when the ferrite magnet 7 having a small coercive force is used.
[0034]
b: Torque
Since the central portion 9 of the cavity 8 has a large depth, the magnetic resistance is considerably large. Therefore, the reluctance torque can be increased. Further, the width Cs2 of the magnetic pole portion iron core 6a is limited by the cavity 8, but the circumferential width to the side end 10 of the portion where the cavity 8 is formed and the radial width on the radially outer side of the cavity 8 are widened. Therefore, it is possible to mitigate a decrease in d-axis inductance due to magnetic saturation of the iron core. Here, as shown in FIG. 1, when the dimension in the radial direction of the ferrite magnet 7 is Mt and the dimension in the circumferential direction of the ferrite magnet 7 is Mw, the relationship of the following equation:
0.3 <magnet thickness (magnetization direction) Mt / magnet width Mw <1.0 (1)
When the magnet shape having the shape of is used, the magnetic resistance of the permanent magnet capable of effectively canceling the armature reaction magnetic flux can be secured, and the high magnetic resistance can be obtained. That is, a large reluctance torque can be obtained at a high power factor. More preferably, the relationship of the following formula:
0,4 <magnet thickness Mt (magnetization direction) / magnet width Mw <0.6 (2)
If the magnet shape has, high values of torque, power factor and variable speed range (small induced voltage) can be obtained.
[0035]
c: Retention of permanent magnet
Since centrifugal force acts on the permanent magnet during rotation, it is necessary to hold the magnet. In the present embodiment, the inner side surface 8s facing the circumferential direction of the cavity 8 is formed so that the mutual distance on the outer side in the radial direction is narrower than the mutual distance closer to the center, and the ferrite magnet 7 is also hollow. 8 is formed so that about half of it is in contact with the central portion 9 of the magnet 8, so that the centrifugal force of the ferrite magnet 7 is received by the inclined inner surface 8s, and a part of the inner surface 8s by the ferrite magnet 7 is received. The concentration of stress can be alleviated, and the iron core can hold the permanent magnet 7 firmly.
[0036]
d: Variable speed operation and efficiency
In a general permanent magnet motor and an embedded permanent magnet motor (IPM), the magnetic flux density of the air gap of the permanent magnet is as high as about 1 [T], and the induced voltage is also high. Iron loss is also significant. In this embodiment, the air gap magnetic flux density of the permanent magnet is about 0.1 to 0.2 [T], and a large output can be obtained even at 1/10 to 1/5 of the magnetic flux of the permanent magnet motor. There are significant advantages.
[0037]
Since an excessive induced voltage is not generated at high speed rotation, the inverter does not damage the power element or capacitor of the inverter.
[0038]
In the present embodiment, the d-axis current is an excitation current that mainly forms a magnetic field, and the q-axis current is a torque current. Therefore, if the d-axis current, which is the excitation current, is reduced as the rotation speed is increased, the operation can be easily performed at a constant voltage up to the high-speed rotation. Therefore, it is not necessary to flow a large current for the weak magnetic flux that cancels the excessive induced voltage due to the magnetic flux of the permanent magnet as in the permanent magnet motor. Moreover, the high-frequency iron loss caused by the weak magnetic flux is also small.
[0039]
The d-axis excitation current and the q-axis torque current can be changed according to the operation state, and the operation can be performed in an optimum state, so that the efficiency is improved over a wide range from a light load to a high load and from a low speed to a high speed rotation.
[0040]
In particular, when there is a state where the rotating electrical machine is idling from the outside, the permanent magnet rotating electrical machine and the embedded permanent magnet rotating electrical machine have a weak magnetic flux for suppressing the induced voltage of the magnet below the power supply voltage during medium and high speed rotation. The current must continue to flow. That is, since a current flows even though no output is generated, power loss due to the generated Joule heat is integrated, and the overall operation efficiency is lowered.
[0041]
On the other hand, in the present embodiment, the induced voltage is about 1/10 that of a conventional permanent magnet rotating electric machine. Therefore, it is not necessary to reduce the induced voltage during idling, and no loss due to Joule heat due to current occurs. Therefore, overall operation efficiency can be improved.
[0042]
Further, since the permanent magnet rotating electric machine generates an output with a magnetic flux and a current, a rare earth magnet that generates a high magnetic flux must be applied. Since rare earth magnets such as NdFeB have low electrical resistance, eddy currents are generated in the magnet due to the harmonic magnetic field, resulting in loss. Furthermore, this loss may cause the magnet to become hot and cause irreversible demagnetization. On the other hand, since the electric resistance of the ferrite magnet is about 100 times that of the rare earth magnet, almost no eddy current is generated, and the overall operation efficiency can be improved. Further, the permanent magnet is not thermally demagnetized due to the rotor loss.
[0043]
e: Reliability:
Since the interlinkage magnetic flux of the winding by the permanent magnet 7 is small, an excessive short-circuit current does not flow even if the winding rotates in an electrically shorted state, and the winding does not burn. Further, even when applied to a drive motor for an electric vehicle, train, etc., a sudden brake does not act upon a short circuit failure, and it can be pulled because the braking force during rotation is slight.
[0044]
Even if the permanent magnet 7 is irreversibly demagnetized, the reluctance torque is mainly used in this embodiment, so that the output is reduced, but it can be driven as a pure reluctance motor.
[0045]
FIG. 4 is a cross-sectional view showing the configuration of the rotor of the second embodiment of the reluctance type rotating electric machine according to the present invention, and FIG. 5 is a partial cross-sectional view showing the vicinity of the cavity between the magnetic poles in an enlarged manner. is there. Here, the rotor 5 </ b> B is formed by forming a concave recess 6 c on the outer peripheral surface on the extension of the center in the circumferential direction of the cavity 8 when viewed from the rotation center O of the rotor core 6. Here, a range in which the rotation center O of the rotor core 6 and the outer edge of the side end portion 10 in the intermediate portion of the adjacent cavity 8 are linearly connected forms the main magnetic pole width Mw. In addition, since it is the same as 1st Embodiment except having formed the hollow 6c, each code | symbol is attached | subjected and the description is abbreviate | omitted.
[0046]
As in the second embodiment, by forming a concave recess 6c on the outer peripheral surface on the extension of the center in the circumferential direction of the cavity 8 of the rotor core 6, the outer periphery of the ferrite magnet 7 between the magnetic poles is formed. The magnetic resistance is further increased. Here, for example, when the width in the circumferential direction from the edge of the recess 6c formed on the radially outer side of the portion where the cavity 8 is formed to the side end portion 10 is Wdb1, and the width on the radially outer side of the cavity 8 is Wbd2. , Wbd2 / Wdb1 ≧ 0.5.
[0047]
As a result, the d-axis bypass magnetic path 6b forms a magnetic circuit from one side end 10 to the other side end 10 of the cavity 8. Assuming that the magnetic flux density at the outer peripheral portion of the d-axis bypass magnetic path 6b is 1 [T], the magnetic saturation is reduced because the central portion (the deepest part from the outer periphery) of the d-axis bypass magnetic path 6b is 2 [T] or less. The influence can be mitigated, the d-axis magnetic resistance is reduced, and the inductance is increased even in the operating region where the current during load is large, so that a large reluctance torque can be obtained.
[0048]
That is, when the difference between the d-axis and q-axis inductance increases and the absolute value of the q-axis magnetic flux decreases, the voltage drop also decreases. Therefore, the maximum rotational speed when driving with a voltage source is improved. Will grow. Thereby, the variable speed range can be further expanded. In this case, a favorable result was obtained when the magnetic pole portion 6a having a low magnetic resistance was composed only of an iron core, and the circumferential width Mw of the magnetic core 6a was 0.15 to 0.35 times the magnetic pole pitch.
[0049]
FIG. 6 shows changes in reluctance torque when the width of the main magnetic pole / magnetic pole pitch is changed in the second embodiment, and changes in the inductance difference obtained by subtracting the q-axis inductance from the d-axis inductance. A large torque and large inductance difference are obtained when the width / pole pitch of the main pole is in the range of 0.15 to 0.35. Preferably, it can be seen that the best value is obtained in the range of 0.2 to 0.3.
[0050]
FIG. 7 is a partial cross-sectional view showing the configuration of the rotor of the third embodiment of the reluctance type rotating electric machine according to the present invention. In the figure, the same elements as those in FIG. The rotor 5C according to this embodiment has a first point in that a gap 14 is provided between the radially outer surface of the ferrite magnet 7 and the outer peripheral side iron core located outside thereof, that is, the d-axis bypass magnetic path 6b. The configuration is different from that of the second embodiment.
[0051]
In FIG. 7, a d-axis bypass magnetic path 6b located on the radially outer side of the ferrite magnet 7 is a magnetic path through which the magnetic flux in the direction along the d-axis, that is, the central axis of the magnetic pole having a low magnetic resistance passes in the circumferential direction. Since the magnetic circuit is arranged in parallel with the magnetic pole, it becomes a bypass magnetic path for the d-axis magnetic flux. The q-axis is a region having a large magnetic resistance, and is a direction along the central axis of the cavity. Since the gap 14 is provided between the ferrite magnet 7 and the d-axis bypass magnetic path 6b located on the outer peripheral side thereof, the centrifugal force of the ferrite magnet 7 is not applied to the d-axis bypass magnetic path 6b, and the central portion 9 of the cavity 8 It is received only by the inclined inner surface 8s. As a result, it is possible to prevent the d-axis bypass magnetic path 6b, which is weak in strength, from being damaged.
[0052]
FIG. 8 is a partial cross-sectional view showing the configuration of the rotor of the fourth embodiment of the reluctance type rotating electric machine according to the present invention. In the figure, the same elements as those in FIG. 5 showing the second embodiment are denoted by the same reference numerals, and the description thereof is omitted. The rotor 5 </ b> D according to this embodiment is configured such that an NdFeB magnet 11 having higher magnetic energy than the ferrite magnet 7 is fitted to the side end portion 10 of the cavity 8. Here, the NdFeB magnet ll has a high coercive force. For example, the coercive force of the ferrite magnet 7 is 300 kA / m, whereas the NdFeB magnet ll is 1000 kA / m. If both are magnets having the same thickness, they can withstand a demagnetizing field caused by a current of about 3 to 4 times. Further, the demagnetizing field due to the current is increased at the side end 10 of the cavity 8.
[0053]
As described above, in the fourth embodiment, the NdFeB magnet 11 having a high coercive force is fitted to the side end portion 10 of the cavity 8, so that the magnetic flux of the permanent magnet is increased without demagnetization. Torque can be increased. The central portion 9 of the cavity 8 has a large magnetic resistance, a high reluctance torque, and at the same time, the ferrite magnet 7 can be thickened.
[0054]
FIG. 9 is a partial cross-sectional view showing the configuration of the rotor of the fifth embodiment of the reluctance type rotating electric machine according to the present invention. In the rotor 5E according to this embodiment, the ferrite magnet 7 is removed from the fourth embodiment shown in FIG. 8, and the central portion 9 of the cavity 8 is made only of air, or a nonmagnetic material (not shown) is used here. ) Is inserted.
[0055]
In the rotating electrical machine according to the present invention, reluctance torque is mainly used, and the torque by the permanent magnet is about 10 to 30% of the total torque. Even if the ferrite magnet 7 is removed from the central portion 9, the magnetic resistance is substantially the same, so that the dominant reluctance torque is slightly reduced. Since the NdFeB magnet 11 has a magnetic energy 10 times that of the ferrite magnet 7, if the volume of the NdFeB magnet 11 is slightly increased from that shown in FIG. It is done.
[0056]
FIG. 10 is a cross-sectional view showing the configuration of the rotor of the sixth embodiment of the reluctance type rotating electric machine according to the present invention. In the figure, the same reference numerals are given to the same elements as those in FIG. 4 showing the second embodiment, and the description thereof is omitted. In the rotor 5F according to this embodiment, the inner surface in the radial direction of the cavity 8A forms a flat surface, the inner surface on the outer side in the radial direction forms a concave arc surface toward the outer side, and the inner surfaces that are opposed to each other in the circumferential direction. The side surface forms a radial plane, and forms an opposite side surface that is widened from the center of rotation. The inside and outside in the radial direction are fitted into the inner surface of the cavity 8A inside the cavity 8A, but resin molded magnets 7b formed in parallel to each other are fitted on the side surfaces in the circumferential direction. A side end 10 is formed. The resin molded magnet 7A is formed of a resin containing rare earth permanent magnet powder. Since the resin molded magnet 7A cannot be held by the iron core 6 on the side surface of the cavity, the resin molded magnet 7A is held by the d-axis bypass magnetic path 6b.
[0057]
In the sixth embodiment, the resin containing the rare earth permanent magnet powder is injected into the cavity 8 of the rotor core, thereby simultaneously forming and inserting the magnet 7A. This simplifies the machining of the resin molded magnet 7A and the process of inserting the magnet 7 into the cavity 8A of the rotor core. Furthermore, mass productivity is improved.
[0058]
In this case, the q-axis magnetic flux interlinking with the armature winding is operated in a state where the magnetic flux caused by the current and the magnetic flux caused by the permanent magnet cancel each other at the time of loading. The torque T at this time is expressed as follows.
[0059]
T = P × (Ld · Id · Iq− (Lq · Iq−ψm) Id) (3)
here,
Ld, Lq: d-axis and q-axis inductances,
Id, Iq: d-axis and q-axis currents,
ψm: Interlinkage magnetic flux of permanent magnet
It is. In the rotating electrical machine according to this embodiment, the magnetic flux due to the q-axis current is canceled by the magnetic flux of the permanent magnet 7 to be zero. That is,
λq = Lq · Iq−ψm = 0 (4)
Since the q-axis magnetic flux λq is 0, the voltage at the time of loading is only the d-axis voltage, and the power factor can be improved. At the same time, as can be seen from the equation (3), the q-axis magnetic flux λq generates a negative torque. By reducing the magnetic flux of λq, which is a magnetic flux leaking into the cavity 8, the negative torque due to λq is reduced. Torque also increases. At the same time, since the total magnetic flux passing through the core back of the iron core is reduced, the magnetic saturation of the iron core back is relaxed and the output is improved.
[0060]
FIG. 11 is a cross-sectional view showing the configuration of the rotor of the seventh embodiment of the reluctance type rotating electric machine according to the present invention. In the figure, the same elements as those in FIG. 10 showing the sixth embodiment are denoted by the same reference numerals, and the description thereof is omitted. The rotor 5G in this embodiment is different from FIG. 10 in that the inner surface of the cavity 8B on the radially inner side is a combination of the center portion of the plane and the inclined surface whose both sides are directed radially outward. Moreover, the point which set it as the resin molding magnet 7B fitted to this shape is only different from FIG. 10, and except this, it is comprised the same as FIG. 10, and the same effect | action and effect are acquired.
[0061]
【The invention's effect】
As is apparent from the above description, according to the present invention, it is possible to provide a reluctance type rotating electrical machine that enables variable speed operation over a wide range with small size, high output, and high efficiency without irreversible demagnetization.
[0062]
In addition, a reluctance type rotating electrical machine with high reliability and excellent manufacturability can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of a first embodiment of a reluctance type rotating electric machine according to the present invention.
2 is an enlarged partial sectional view showing the vicinity of a cavity between magnetic poles of the rotor of the first embodiment shown in FIG. 1;
FIG. 3 is an explanatory diagram showing paths of armature magnetic fluxes of d-axis and q-axis in order to explain the operation of the first embodiment shown in FIG. 1;
FIG. 4 is a cross-sectional view showing a configuration of a rotor according to a second embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 5 is an enlarged partial cross-sectional view showing the vicinity of a cavity between magnetic poles of a rotor according to the second embodiment shown in FIG. 4;
FIG. 6 is a diagram showing the relationship between the main magnetic pole width / magnetic pole pitch and the torque and d-axis and q-axis inductance differences in order to explain the operation of the second embodiment according to the present invention;
FIG. 7 is a partial cross-sectional view showing a configuration of a rotor of a third embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 8 is a partial cross-sectional view showing a configuration of a rotor according to a fourth embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 9 is a partial cross-sectional view showing a configuration of a rotor of a fifth embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 10 is a cross-sectional view showing a configuration of a rotor of a sixth embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 11 is a cross-sectional view showing a configuration of a rotor of a seventh embodiment of a reluctance type rotating electric machine according to the present invention.
FIG. 12 is a cross-sectional view of a conventional reluctance type rotating electric machine.
[Explanation of symbols]
1 Armature
2 Armature core
3 Armature coil
4 Armature teeth
5,5A ~ 5G rotor
6 Rotor core
6a Iron core
6b d-axis bypass magnetic path
7 Ferrite magnet
7A, 7B resin molded magnet
8,8A, 8B cavity
9 Center of the cavity
10 Side edge of the cavity
11 NdFeB magnet
12 Convex part of rotor (magnetic pole)
13 Concave part of rotor
14 Clearance

Claims (10)

In a reluctance type rotating electrical machine comprising an armature having an armature coil and a rotor having a portion having different magnetic resistance in the circumferential direction,
As a large portion of the magnetic resistance of the rotor, and a central portion and side edge portions extending radially outwardly and connected to both sides of the circumferential direction with respect to the central portion, than the magnetic resistance of the central portion Also, in order to reduce the magnetic resistance of the side end portion, a cavity having a circumferential dimension of the side end portion smaller than a radial dimension of the central portion,
A ferrite magnet fitted in the center of the cavity and magnetized to cancel the magnetic flux of the armature current through the cavity;
And the opposite inner side surfaces located on both sides in the circumferential direction of the central portion of the cavity are each formed in a planar shape, and are on the side farther outward in the radial direction compared to the mutual spacing near the center of rotation Are formed with a narrower mutual interval, and this inclined surface receives a part of the centrifugal force acting on the ferrite magnet during rotation ,
Further, the side end portions formed continuously on both sides in the circumferential direction of the central portion are formed so as to have an inner surface smoothly continuing on an extension line of the inner surface on the radially outer side of the central portion. In this way, a smooth magnetic path is formed between the peripheral edge of the rotor core and the central portion and the side end portion.
A reluctance rotary electric machine characterized by that. The reluctance type rotating electrical machine according to claim 1, wherein a dimension of the side end portion in the circumferential direction is set to be five times or more of an air gap length.   The reluctance rotating electric machine according to claim 1 or 2, wherein the ferrite magnet has a radial thickness of 0.3 to 1.0 times based on a circumferential width. The reluctance type rotating electric machine according to claim 1 , wherein a gap is provided between a radially outer surface of the ferrite magnet and an inner surface of the cavity facing the ferrite magnet. Based on the intersection of the center line passing through the middle of the cavity and the outer periphery of the rotor, the thickness to the radially outer side surface of the cavity is 0.5 times the circumferential distance to the side end. It is the above, The reluctance type rotary electric machine of any one of Claim 1 thru | or 4 characterized by the above-mentioned. The reluctance type rotating electric machine according to any one of claims 1 to 5, wherein a concave depression is formed at an intersection between a center line passing through an intermediate portion of the cavity and an outer periphery of the rotor. . Small sites reluctance of the rotor is constituted by the magnetic poles of the iron core alone, and the circumferential width of the magnetic pole, to claim 1, characterized in that a 0.15 to 0.35 times the pole pitch The permanent magnet type reluctance type rotating electrical machine according to any one of 6 . The permanent magnet type reluctance type rotating electric machine according to any one of claims 1 to 7 , wherein a permanent magnet having higher magnetic energy than the ferrite magnet is fitted to each side end of the cavity. The reluctance rotating electric machine according to claim 8, wherein the permanent magnet is made of resin and magnet powder. In interlinked q-axis magnetic flux in the armature winding, one of the claims 1 to 9 magnetic flux generated by the magnetic flux and the ferrite magnets or permanent magnet by the current when the load is equal to or be operated with a zero is offset The reluctance type rotating electrical machine according to claim 1.

Images