JP2010130859A - Permanent magnet type dynamo electric machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To uniformly magnetize the upper and lower layers and intermediate layer of a variable magnetic-force magnet. <P>SOLUTION: A rotor 1 is composed of a rotor core 2, the variable magnetic-force magnets 3 and fixed magnetic-force magnets 4. The variable magnetic-force magnets 3 are configured by superposing magnet variable magnetic-force magnets 3a and 3c having a strong coercive force and the variable magnetic-force magnets 3b having a weak coercive force in the direction of magnetization of each magnet. The magnets superposed in series are arranged in the rotor core 2 at positions where the direction of magnetization is the d-axis direction. The fixed magnetic-force magnets 4 and 4 are arranged at positions where the direction of magnetization is the d-axis direction on both sides of the magnets superposing the variable magnetic-force magnets 3 and the fixed magnetic-force magnets 4a in series. When the interlinking magnetic flux of the variable magnetic-force magnets 3 is reduced, a magnetic field in the direction opposite to the direction of magnetization of the variable magnetic-force magnets 3 is worked by a current in an armature winding. Since the intermediate layer receiving a comparatively weak magnetic field in the variable magnetic-force magnets 3 is composed of the variable magnetic-force magnets 3b having the weak coercive force, the whole of the variable magnetic-force magnets 3 is magnetized uniformly. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses two or more types of permanent magnets, and irreversibly changes the amount of magnetic flux of at least one of the permanent magnets, thereby enabling a variable speed operation in a wide range from low speed to high speed. It relates to a rotating electrical machine.

  Generally, permanent magnet type rotating electrical machines are roughly divided into two types. They are a surface magnet type permanent magnet type rotating electrical machine in which a permanent magnet is attached to the outer periphery of a rotor core, and an embedded type permanent magnet type rotating electrical machine in which a permanent magnet is embedded in a rotor core. As the variable speed drive motor, an embedded permanent magnet type rotating electrical machine is suitable.

  In the permanent magnet type rotating electrical machine, the interlinkage magnetic flux of the permanent magnet is always generated with a constant strength, so that the induced voltage by the permanent magnet increases in proportion to the rotational speed. Therefore, when variable speed operation is performed from low speed to high speed, the induced voltage (back electromotive voltage) by the permanent magnet becomes extremely high at high speed rotation. When the induced voltage by the permanent magnet is applied to the electronic component of the inverter and exceeds its withstand voltage, the electronic component breaks down. For this reason, it is conceivable to perform a design in which the amount of magnetic flux of the permanent magnet is reduced so as to be equal to or lower than the withstand voltage, but in that case, the output and efficiency in the low speed region of the permanent magnet type rotating electrical machine are reduced.

  When performing variable speed operation close to constant output from low speed to high speed, the interlinkage magnetic flux on the right of the permanent magnet is constant, so the rotating electrical machine voltage reaches the upper limit of the power supply voltage in the high-speed rotation range, and the current required for output flows. Disappear. As a result, the output is greatly reduced in the high-speed rotation region, and further, variable speed operation cannot be performed over a wide range up to high-speed rotation.

  Recently, as a method for expanding the variable speed range, the flux-weakening control as described in Non-Patent Document 1 has begun to be applied. The total amount of interlinkage magnetic flux of the armature winding is composed of a magnetic flux caused by a d-axis current and a magnetic flux caused by a permanent magnet. In the flux weakening control, by generating a magnetic flux due to a negative d-axis current, the total flux linkage is reduced by the magnetic flux due to this negative d-axis current. Even in the flux-weakening control, the permanent magnet having a high coercive force changes the operating point of the magnetic characteristics (BH characteristics) within a reversible range. For this reason, the NdFeB magnet having a high coercive force is applied to the permanent magnet so that the permanent magnet is not irreversibly demagnetized by the demagnetizing field of the magnetic flux control.

  In operation using the flux-weakening control, the linkage flux decreases due to the magnetic flux due to the negative d-axis current, and therefore the decrease in linkage flux creates a voltage margin with respect to the voltage upper limit value. And since the electric current which becomes a torque component can be increased, the output in a high speed region increases. Further, the rotational speed can be increased by the voltage margin, and the range of variable speed operation is expanded.

  However, since the negative d-axis current that does not contribute to the output is constantly flowing, the copper loss increases and the efficiency deteriorates. Further, the demagnetizing field due to the negative d-axis current generates a harmonic magnetic flux, and the increase in the voltage generated by the harmonic magnetic flux or the like is weakened to create a limit of voltage reduction by the magnetic flux control. Therefore, even if the flux-weakening control is applied to the embedded permanent magnet type rotating electrical machine, it is difficult to perform variable speed operation at three times the specified speed or more. Furthermore, there is a problem that the iron loss increases due to the above-described harmonic magnetic flux, and the efficiency is greatly lowered in the middle and high speed ranges. Further, there is a possibility that vibration is generated by electromagnetic force generated by the harmonic magnetic flux.

  When an embedded permanent magnet motor is applied to a drive motor for a hybrid vehicle, the motor is rotated when driven by an engine alone. In medium / high speed rotation, the induced voltage of the motor's permanent magnet rises. Therefore, in order to suppress it within the power supply voltage, the negative d-axis current is kept flowing by the flux weakening control. In this state, since the electric motor generates only a loss, the overall operation efficiency is deteriorated.

  When an embedded permanent magnet motor is applied to a train drive motor, the train is in a coasting state, and in the same way as above, a negative d-axis current is controlled by a weak magnetic flux control so that the induced voltage by the permanent magnet is lower than the power supply voltage. Continue to flow. In that case, since the electric motor generates only a loss, the overall operation efficiency deteriorates.

  As a technique for solving such a problem, Patent Documents 1 and 2 disclose a permanent magnet having a low coercive force (hereinafter, referred to as “magnetic coercive force”) whose magnetic flux density is irreversibly changed by a magnetic field generated by a current of a stator winding. Variable magnets) and high coercivity permanent magnets (hereinafter referred to as fixed magnets) that have a coercive force more than twice that of variable magnets. A technique is described in which the amount of total interlinkage magnetic flux is adjusted by magnetizing a variable magnetic magnet with a magnetic field generated by a current so that the total interlinkage magnetic flux between the magnet and the fixed magnetic magnet is reduced.

  The permanent magnet type rotating electrical machine of Patent Document 1 includes a rotor 1 having a configuration as shown in FIG. That is, the rotor 1 includes a rotor core 2, eight variable magnetic magnets 3, and eight fixed magnetic magnets 4. The rotor core 2 is configured by laminating silicon steel plates, the variable magnetic force magnet 3 is an alnico magnet or an FeCrCo magnet, and the fixed magnetic force magnet 4 is an NdFeB magnet.

  The variable magnetic force magnet 3 is embedded in the rotor core 2, and first cavities 5 are provided at both ends of the variable magnetic force magnet 3. The variable magnetic force magnet 3 is disposed along the radial direction of the rotor that coincides with the q axis serving as the central axis between the magnetic poles, and is magnetized in a direction perpendicular to the radial direction. The fixed magnetic magnet 4 is embedded in the rotor core 2, and second cavities 6 are provided at both ends of the fixed magnetic magnet 4. The fixed magnetic magnet 4 is disposed substantially in the circumferential direction of the rotor 1 so as to be sandwiched between the two variable magnetic magnets 3 on the inner peripheral side of the rotor 1. The fixed magnetic magnet 4 is magnetized in a direction substantially perpendicular to the circumferential direction of the rotor 1.

  The magnetic pole portion 7 of the rotor core 2 is formed so as to be surrounded by two variable magnetic magnets 3 and one fixed magnetic magnet 4. The central axis direction of the magnetic pole part 7 of the rotor core 2 is the d axis, and the central axis direction between the magnetic poles is the q axis. In the permanent magnet type rotating electrical machine of Patent Document 1 adopting this rotor 1, a magnetic field is formed by passing a pulsed current whose energization time is extremely short (about 100 μs to 1 ms) to the stator winding to make it variable. A magnetic field is applied to the magnetic magnet 3. If the magnetizing magnetic field is 250 kA / m, ideally, a sufficient magnetizing magnetic field acts on the variable magnetic force magnet 3, and the fixed magnetic force magnet 4 does not undergo irreversible demagnetization due to magnetization.

  As a result, in the permanent magnet type rotating electrical machine disclosed in Patent Document 1, the amount of interlinkage magnetic flux of the variable magnetic force magnet 3 can be greatly changed from the maximum to 0 by the d-axis current of the rotor 1, and the magnetization direction can be changed in both forward and reverse directions. . That is, assuming that the linkage magnetic flux of the fixed magnetic magnet 4 is in the positive direction, the linkage magnetic flux of the variable magnetic magnet 3 can be adjusted over a wide range from the maximum value in the positive direction to 0 and further in the reverse direction. Therefore, in the rotor of the present embodiment, the total interlinkage magnetic flux combined with the variable magnetic magnet 3 and the fixed magnetic magnet 4 can be adjusted over a wide range by magnetizing the variable magnetic magnet 3 with the d-axis current. .

  For example, in the low speed range, the variable magnetic magnet 3 is magnetized with the d-axis current so as to have the maximum value in the same direction (initial state) as the interlinkage magnetic flux of the fixed magnetic magnet 4, so that the torque by the permanent magnet becomes the maximum value. Therefore, the torque and output of the rotating electrical machine can be maximized. In the middle / high speed range, the voltage of the rotating electrical machine is lowered by reducing the amount of magnetic flux of the variable magnetic magnet 3 and lowering the total flux linkage, so that there is room for the upper limit of the power supply voltage and the rotational speed ( (Frequency) can be further increased.

  FIGS. 18A to 18D are schematic views for explaining this. In the permanent magnet type rotating electrical machine of Patent Document 1, as shown in FIG. 18A, two variable magnetic magnets 3 and one fixed magnetic magnet 4 are arranged in a U shape with the d axis as the center. In the normal operation state of the electric motor, the direction of the magnetic flux of the variable magnetic magnet 3 and the fixed magnetic magnet 4 is directed toward the central magnetic pole portion 7. In this state, when a d-axis current is applied in a pulsed manner to generate a magnetic field for demagnetization, the magnetic flux is changed from the outer peripheral side of the rotor 1 to the variable magnetic magnet 3 and the fixed magnetic magnet as shown in FIG. 4 so that the variable magnetic force magnet 3 is demagnetized. At this time, the fixed magnet 4 is not demagnetized because of its high coercivity.

  In the case of this demagnetization, as shown in FIG. 18C, the magnetic flux of the fixed magnetic magnet 4 is changed from the inner direction to the outer side of the variable magnetic magnet 3 along with the d-axis direction. Flows in the opposite direction, and assists the demagnetizing action by the magnetic field generated by the d-axis current. Therefore, demagnetization until the polarity of the variable magnetic force magnet 3 is reversed is possible.

  On the other hand, in the case of magnetization, a variable magnetic force magnet demagnetized by a reverse magnetic flux that generates a magnetic field in the opposite direction by applying a d-axis current again in a pulsed manner. The flux linkage 3 is returned to the normal operation state of (A).

JP 2006-280195 A JP 2008-48514 A

  In the permanent magnet type rotating electrical machine of Patent Document 1 having the above-described configuration, the amount of interlinkage magnetic flux of the variable magnetic force magnet 3 can be greatly changed from the maximum to 0 by the d-axis current of the rotor 1, and the magnetization direction is also positive. It has an excellent characteristic that it can be made in both opposite directions. However, there is a problem in that the magnetic field applied to the variable magnetic force magnet 3 by the d-axis current is not distributed in a uniform magnetic field within the magnet. That is, as shown in FIG. 2A, the magnetic field due to the d-axis current is weaker in the central portion of the variable magnetic force magnet 3 than in the upper and lower portions.

  Since such a magnetic field non-uniformity occurs in the variable magnetic force magnet 3, even if a magnetic field having a magnetization intensity is applied to the variable magnetic force magnet 3, only the peripheral portion is magnetized and the central portion is sufficiently magnetized. Therefore, the amount of change in the flux linkage could not be increased. Therefore, in order to prevent the non-uniformity of the magnetic field, it has been necessary to devise such as limiting the thickness of the variable magnetic force magnet 3.

  The present invention has been made to solve the above-described problems, and as a variable magnetic magnet to be installed in a rotor, a plurality of variable magnetic magnets having different coercive forces are combined to uniformly magnetize the variable magnet. Thus, the object is to increase the amount of change in the linkage flux of the variable magnetic magnet. In addition, the present invention enables a variable speed operation in a wide range from low speed to high speed, high torque in the low speed rotation range, high output in the middle / high speed rotation range, and improvement in efficiency. The purpose is to provide an electric machine.

  The permanent magnet rotating electric machine of the present invention forms a magnetic pole of a rotor using two or more kinds of permanent magnets having a product of coercive force and magnetization direction thickness different from those of other permanent magnets, and a magnetic field generated by the current of the armature winding. Accordingly, among the two or more types of permanent magnets, a permanent magnet having a small product of coercive force and magnetization direction thickness is magnetized to irreversibly change the amount of magnetic flux of the permanent magnet constituting the magnetic pole, A composite magnet is constructed by laminating a permanent magnet having a small product of the coercive force and the magnetization direction thickness by a magnetic field generated by a current, and a plurality of permanent magnets having different values of the product of the coercive force and the magnetization direction thickness. The product of the coercive force and magnetization direction thickness of the permanent magnet located in the center of the composite magnet is the product of the coercivity and magnetization direction thickness of the permanent magnet located in at least one of the upper or lower layer of the composite magnet. It is characterized by being set smaller.

  In the present invention, two or more kinds of permanent magnets are arranged in series and parallel on the magnetic circuit for each magnetic pole of the rotor, and two or more kinds of permanent magnets are arranged in series and parallel on the magnetic circuit between the plurality of magnetic poles. It is also possible to do. Further, it is possible to provide a magnetic barrier or a short-circuit coil for each magnetic pole.

  According to the present invention having the above-described configuration, by combining a plurality of variable magnetic magnets having different coercive forces as variable magnetic magnets installed in the rotor, the entire variable magnetic magnet is uniformly magnetized, Since the amount of change in the linkage flux of the variable magnetic magnet can be increased, the efficiency of the rotating machine can be increased.

  Hereinafter, an embodiment of a permanent magnet type rotating electrical machine according to the present invention will be described with reference to FIGS. The rotating electrical machine of the present embodiment has been described in the case of 12 poles, and can be similarly applied to other pole numbers.

(1. First embodiment)
(1-1. Configuration)
A first embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, a rotor 1 according to a first embodiment of the present invention includes a rotor core 2, a permanent magnet (hereinafter referred to as a variable magnetic force magnet) 3 in which a product of a coercive force and a magnetization direction thickness is small, It is composed of a permanent magnet (hereinafter referred to as a fixed magnetic magnet) 4 having a large product of coercive force and magnetization direction thickness. The rotor core 2 is formed by laminating silicon steel plates, and the variable magnetic magnet 3 and the fixed magnetic magnet 4 are embedded in the rotor core 2. The variable magnetic force magnet 3 is formed by stacking variable magnetic force magnets having different coercive forces. The variable magnetic force magnets 3a and 3c having strong coercive force are arranged in the upper layer portion and the lower layer portion, and the coercive force is variable magnetic magnets 3a and 3c. A weaker variable magnetic force magnet 3b is disposed in the middle layer.

  The variable magnetic magnet 3 can be a samarium cobalt magnet or an alnico magnet. The fixed magnetic magnet 4 can be an NdFeB magnet. In the present embodiment, the variable magnetic force magnets 3a and 3c are samarium cobalt magnets having a coercive force of 300 kA / m, the variable magnetic force magnet 3b is a samarium cobalt magnet having a coercive force of 200 kA / m, and the fixed magnetic force magnet 4 has a coercive force. A 1000 kA / m NdFeB magnet is used.

  The variable magnetic magnets 3a to 3c are superposed in the magnetization direction of each magnet to constitute one variable magnetic magnet. That is, the variable magnetic force magnets 3a to 3c are magnetically arranged in series with the same magnetization direction. The variable magnetic magnets 3 stacked in series are arranged in the rotor core 2 at a position where the magnetization direction is in the d-axis direction (here, approximately the radial direction of the rotor). On the other hand, the fixed magnetic magnets 4 and 4 are arranged on both sides of the variable magnetic magnet 3 at positions where the magnetization direction is the d-axis direction. The fixed magnetic magnets 4, 4 arranged on the side constitute a parallel circuit on the magnetic circuit with respect to the laminated variable magnetic magnet 3.

  A cavity 6 is provided at the ends of the variable magnetic magnet 3 and the fixed magnetic magnet 4 so that the magnetic flux passing through the rotor core 2 passes through the variable magnetic magnet 3 and the fixed magnetic magnet 4 in the thickness direction. In particular, cavities 5 serving as magnetic barriers are provided above and below the fixed magnetic magnet 4 so that the magnetic flux is concentrated on the variable magnetic magnet 3. The magnetic pole part 7 of the rotor core 2 is formed so as to be surrounded by one variable magnetic magnet 3 and two fixed magnetic magnets 4. The central axis direction of the magnetic pole part 7 of the rotor core 2 is the d axis, and the central axis direction between the magnetic poles is the q axis.

  An upper short circuit coil 8a and a lower short circuit coil 8b are provided so as to surround the fixed magnetic magnets 4 and 4 in parallel with the upper and lower surfaces of the fixed magnetic magnets 4 and 4 on both sides. At this time, the short-circuit coils 8a and 8b are set so that the magnetization direction of the fixed magnetic force magnet 4 is the central axis. The short-circuit coils 8a and 8b are made of a ring-shaped conductive member and are mounted so as to be fitted into the edge portion of the cavity 6 provided in the rotor core 2. It is also possible to manufacture by casting a conductive member melted at a high temperature into the hole of the rotor core 2.

  The short-circuit coils 8a and 8b are magnetic fluxes generated when a d-axis current is passed through the armature windings, and generate a short-circuit current. The short-circuit current flowing through the short-circuit coils 8a and 8b flows within 1 second with such a strength that the magnetization of the permanent magnets 3a, 3b and 3c to be irreversibly changed, and then attenuates 50% or more within 1 second. It is preferable. Further, when the inductance value and the resistance value of the short-circuit coil 8 are set to values that allow a short-circuit current to flow to the extent that the magnetization of the variable magnetic force magnet 3 changes, the efficiency is good.

  A stator 10 is provided on the outer periphery of the rotor 2 through an air gap. The stator 10 has an armature core 11 and an armature winding 12. An induced current is induced in the short-circuit coils 8a and 8b by the magnetizing current flowing in the armature winding 12, and a magnetic flux penetrating the short-circuit coils 8a and 8b is formed by the induced current. Further, the magnetization direction of the variable magnetic force magnet 3 is irreversibly changed by the magnetization current (d-axis current) flowing through the armature winding 12.

  That is, with respect to the variable magnetic force magnets 3a to 3c, during operation of the permanent magnet type rotating electric machine, the variable magnetic force magnet 3 is magnetized by a magnetic field generated by the d-axis current, and the amount of magnetic flux is irreversibly changed. In that case, the d-axis current for magnetizing the variable magnetic force magnet 3 is supplied, and at the same time, the torque of the rotating electrical machine is controlled by the q-axis current.

  Also, the linkage of armature windings generated by the current (total current obtained by combining the q-axis current and the d-axis current) and the variable magnetic magnets 3a to 3c and the fixed magnetic magnets 4 and 4 due to the magnetic flux generated by the d-axis current. The entire armature winding composed of the amount of magnetic flux, that is, the magnetic flux generated in the armature winding by the total current of the rotating electrical machine and the magnetic flux generated by the two or more types of permanent magnets 3a to 3c, 4, 4 on the rotor side The amount of flux linkage is changed almost irreversibly.

  In particular, in the present embodiment, the variable magnetic magnets 3a to 3c are irreversibly changed by a magnetic field generated by an instantaneous large d-axis current. In this state, operation is carried out by continuously supplying a d-axis current in a range where little or no irreversible demagnetization occurs. The d-axis current at this time acts to adjust the terminal voltage by advancing the current phase.

  Further, an operation control method is performed in which the polarity of the variable magnetic force magnet 3 is reversed with a large d-axis current to advance the current phase. As described above, since the polarity of the variable magnetic force magnet 3 is reversed by the d-axis current, even if a negative d-axis current that reduces the terminal voltage is passed, the variable magnetic force magnet 3 is not demagnetized but increased. Become. That is, the magnitude of the terminal voltage can be adjusted without demagnetizing the variable magnetic force magnet 3 with a negative d-axis current.

  In a general magnet motor, since the polarity of the magnet is not reversed, if the d-axis current increases by advancing the current phase, there is a problem that the magnet is irreversibly demagnetized. It is possible to advance the phase by reversing the polarity.

(1-2. Basic action)
Next, the operation of the first embodiment will be described.
In the present embodiment, a magnetic field is formed by flowing a pulse-like current having an energization time of about 0.1 ms to 100 ms (10 ms in the present embodiment) through the armature winding of the stator to form a variable. A magnetic field is applied to the magnetic magnet 3. A pulse current that forms a magnetic field for magnetizing the variable magnetic force magnet 3 is a d-axis current component of the armature winding of the stator. If the thicknesses of the variable magnetic magnet 3 and the fixed magnetic magnet 4 are substantially equal, the change in the magnetization state of the permanent magnet due to the applied magnetic field due to the d-axis current changes depending on the magnitude of the coercive force.

  If the thicknesses of the variable magnetic magnet 3 and the fixed magnetic magnet 4 are substantially equal, the change in the magnetization state of the permanent magnet due to the applied magnetic field due to the d-axis current varies depending on the magnitude of the coercive force. That is, the change in the magnetization state of the permanent magnet due to the applied magnetic field is approximated by the product of the magnitude of the coercive force and the thickness of the permanent magnet. As described above, in this embodiment, the coercive force of the variable magnetic magnets 3a and 3c is set to 300 kA / m, the coercive force of the variable magnetic magnet 3b is set to 200 kA / m, and the coercive force of the fixed magnetic magnet 4 is set to 1000 kA / m. Yes.

  At this time, the coercive force of the fixed magnetic magnet 4 is 3 to 5 times the coercive force of the variable magnetic magnets 3a to 3c. Therefore, the magnetic force of the fixed magnetic magnet 4 can be maintained unchanged with the current that can change the magnetic force of the variable magnetic magnets 3a to 3c. Thus, when these magnets are combined in parallel to form a magnet, the total magnetic flux linkage of the permanent magnet is obtained by maintaining the magnetic force of the fixed magnetic magnet 4 as a base and changing the magnetic force of the variable magnetic magnet 3. Can be adjusted.

  First, a negative d-axis current that generates a magnetic field in a direction opposite to the magnetization direction of the magnet is applied to the armature winding in a pulsed manner. Assuming that the magnetic field in the magnet changed by the negative d-axis current becomes 350 kA / m, the coercive force of the variable magnetic magnet 3a is 300 kA / m, so that the magnetic forces of the variable magnetic magnets 3a to 3c are irreversibly greatly reduced. On the other hand, since the coercive force of the fixed magnetic magnet 4 is 1000 kA / m, the magnetic force does not decrease irreversibly. As a result, when the pulsed d-axis current becomes zero, only the variable magnetic force magnet 3 is demagnetized, and the amount of interlinkage magnetic flux by the entire magnet can be reduced.

  Next, a positive d-axis current that generates a magnetic field in the same direction as the magnetization direction of the permanent magnet is applied to the armature winding. A magnetic field necessary for magnetizing the variable magnetic force magnet 3 is generated. If the magnetic field in the magnet changed by the positive d-axis current is 350 kA / m, the demagnetized variable magnetic force magnet 3 is magnetized to generate a maximum magnetic force. On the other hand, since the coercive force of the fixed magnetic magnet 4 is 1000 kA / m, the magnetic force does not change irreversibly. As a result, when the pulsed positive d-axis current becomes 0, only the variable magnetic force magnet 3 is magnetized, and the amount of flux linkage by the entire magnet can be increased. This makes it possible to return to the original maximum flux linkage.

  As described above, by applying an instantaneous magnetic field due to the d-axis current to the variable magnetic magnet 3 and the fixed magnetic magnet 4, the magnetic force of the variable magnetic magnet 3 is irreversibly changed, and the total interlinkage magnetic flux of the permanent magnet Can be arbitrarily changed.

  In this case, the variable magnetic force magnet 3 is magnetized so that the magnetic flux of the permanent magnet of the magnetic pole is added at the time of the maximum torque of the permanent magnet type rotating electric machine, and at a light load with a small torque or in the middle speed rotation range and the high speed rotation range. The variable magnetic force magnet 3 is magnetized by a magnetic field caused by an electric current to reduce the magnetic flux, or by reversing the polarity, thereby reducing the amount of flux linkage of the permanent magnet. In addition, when the rotor reaches the maximum rotational speed with the magnetic flux magnet minimized by irreversibly changing the magnetic pole magnet, the induced electromotive force generated by the permanent magnet is resistant to the inverter electronic components that are the power source of the rotating electrical machine. Below voltage.

(1-3. Action of serial arrangement)
In the present embodiment, the variable magnetic force magnets 3a to 3c are magnetically arranged in series as the variable magnetic force magnet 3, so that when the variable magnetic force magnet 3 is demagnetized and magnetized, FIG. The conventional single-layer variable magnetic force magnet 3 shown in FIG. This point will be described with reference to FIG.

  FIG. 2B is a distribution diagram of magnetic fields in the variable magnetic force magnets 3a to 3c of the present embodiment during magnetization. Similar to the single-layer variable magnetic magnet 3, the magnetic field applied to the variable magnetic magnet 3 by the d-axis current is not distributed in a uniform magnetic field in the magnet, and the magnetic fields of the upper and lower portions of the variable magnetic magnet 3 are compared to the central portion. It gets quite expensive.

  However, in this embodiment, as shown in FIG. 2B, the variable magnetic magnets 3a and 3c having a coercive force of 300 kA / m are arranged in the upper layer part and the lower layer part, and the coercive force is 200 kA / m in the middle layer part. A variable magnetic magnet 3b is arranged. Thereby, since a strong magnetic field acts on the upper layer part and the lower layer part of the variable magnetic force magnet 3 by the d-axis current, the variable magnetic force magnets 3a and 3c having a coercive force of 300 kA / m can be magnetized. On the other hand, a relatively weak magnetic field acts on the central portion of the variable magnetic force magnet 3, but the variable magnetic force magnet 3b disposed in the middle layer portion has a small coercive force of 200 kA / m. The part can be sufficiently magnetized.

(1-4. Action of magnetic barrier)
The action of the magnetic barrier provided on the outer periphery of the fixed magnetic magnets 4 and 4 will be described with reference to FIG. The cavities 5 and 6 serving as magnetic barriers are provided not on the outer peripheral portion of the magnets on which the variable magnetic force magnets 3 are stacked, but on the outer peripheral portions of the fixed magnetic force magnets 4 and 4 arranged in parallel. Since the fixed magnetic magnets 4 and 4 have a magnetic barrier, the magnetic field a due to the d-axis current is small.

  On the other hand, since there is no magnetic barrier around the magnet on which the variable magnetic force magnet 3 is laminated, the magnetic field generated by the d-axis current can be increased. As a result, the magnetic field A caused by the d-axis current can be effectively applied to the magnet on which the variable magnetic force magnet 3 is laminated. Also, with respect to the magnetic flux that increases due to the d-axis current, the increase in the amount of magnetic flux that passes through the fixed magnetic magnets 4 and 4 can be suppressed, so that the magnetic saturation of the iron core can be mitigated and the d-axis for changing the magnetization of the variable magnetic magnet 3 The current can also be reduced.

  As shown in FIG. 4, the q-axis magnetic flux B is distributed so as to cross the iron core on the outer periphery of the magnet. However, since there are cavities 5 and 6 serving as magnetic barriers, the magnetic path cross-sectional area is narrowed and the magnetic resistance is high. Become. Therefore, the q-axis inductance can be reduced and the terminal voltage can be lowered.

(1-5. Action of short-circuit coil)
Next, the operation of the short-circuit coils 8a and 8b will be described with reference to FIG. Since the variable magnetic magnet 3 and the fixed magnetic magnet 4 are embedded in the rotor core 2 to form a magnetic circuit, the magnetic field due to the d-axis current is applied not only to the variable magnetic magnet 3 but also to the fixed magnetic magnet 4. Works. Originally, the magnetic field generated by the d-axis current is used to change the magnetization of the variable magnetic force magnet 3.

  Therefore, the magnetic field due to the d-axis current may be prevented from acting on the fixed magnetic magnets 4 and 4 and concentrated on the variable magnetic magnet 3. In the present embodiment, short-circuit coils 8 are arranged above and below the fixed magnetic magnets 4 and 4. The short-circuit coil is arranged with the magnetization direction of the fixed magnetic magnets 4 and 4 as the central axis. When a magnetic field due to the d-axis current acts on the fixed magnetic magnets 4 and 4, an induced current that cancels the magnetic field flows through the short-circuit coils 8a and 8b. Therefore, in the fixed magnetic magnets 4 and 4, there is almost no increase or decrease in the magnetic field due to the magnetic field due to the d-axis current and the magnetic field due to the short-circuit current. Furthermore, the magnetic field due to the short-circuit current also acts on the variable magnetic force magnet 3 and is in the same direction as the magnetic field due to the d-axis current.

  Therefore, the magnetic field that magnetizes the variable magnetic force magnet 3 is strengthened, and the variable magnetic force magnet 3 can be magnetized with a small d-axis current. In this case, in the present embodiment, the magnetic field generated by the short-circuit coils 8a and 8b is strongly applied to the upper and lower layers of the variable magnetic force magnet 3 and is not so much applied to the middle layer portion. Since the variable magnetic force magnet 3b is composed of a magnet having a weak coercive force, nonuniform magnetization does not occur. Further, since the fixed magnetic magnets 4 and 4 are not affected by the d-axis current due to the short-circuit coil and the magnetic flux hardly increases, the magnetic saturation of the armature core due to the d-axis current can be reduced.

  A conductive plate may be provided on the lower surface of the fixed magnetic force magnets 4 and 4 (inner peripheral side of the rotor) instead of the short-circuit coil 8b. It is preferable to use a copper plate or an aluminum plate as the conductive plate. In addition, the conductive plate is not limited to the lower surface of the fixed magnetic magnets 4 and 4, but may be disposed on the upper surface (the outer peripheral side of the rotor). There is a merit that an induced current is generated in the insulating plate and the harmonics can be reduced.

  In such a configuration, when a magnetic field generated by the magnetizing current is applied to the conductive plate, an induced current (eddy current) is generated on the surface of the conductive plate, and as in the case of the short-circuit coils 8a and 8b. Magnetic field is generated. Due to the magnetic field, there is almost no increase or decrease in the magnetic field due to the d-axis current and the short-circuit current in the fixed magnetic magnets 4 and 4. Furthermore, the magnetic field due to the short-circuit current also acts on the variable magnetic force magnet 3 and is in the same direction as the magnetic field due to the d-axis current. At the same time, the effect of relaxing the magnetic saturation of the armature core 11 is also exhibited.

(1-6. Action of air gap length)
In the first embodiment, as shown in FIG. 1, the air gap length L1 in the vicinity where the fixed magnetic magnet 4 is arranged is longer than the air gap length L2 in the vicinity where the variable magnetic magnet 3 is arranged. And

  In the present embodiment, the magnetic field generated by the d-axis current is intended to act on the variable magnetic force magnet 3, but a leakage magnetic field is also generated. Therefore, in the present embodiment, the air gap length L2 near the q axis is made larger than the air gap length L1 near the d axis. That is, since the air gap length is shorter in the vicinity where the variable magnetic force magnet 3 is disposed, the magnetic resistance of the air gap portion is reduced.

  Accordingly, the magnetic field generated by the d-axis current for magnetizing the magnet can be concentrated on the variable magnetic force magnet 3 disposed in the d-axis portion, and at the same time, a high magnetic field can be applied, and the variable magnetic force can be reduced with a small d-axis current. The magnet 3 can be effectively magnetized. In addition, since the q-axis side magnetic resistance can be increased, the inductance of the rotating electrical machine can be reduced and the power factor can be improved. As another example, a nonmagnetic portion that increases the magnetic resistance in the q-axis direction may be provided in the rotor core.

(1-7. Effect)
In the present embodiment having the configuration and operation as described above, the following effects can be obtained.
(1) Even if the magnetic field applied to the variable magnetic magnet 3b in the central portion of the variable magnetic magnet 3 by the d-axis current is weaker than the variable magnetic magnets 3a and 3c in the upper and lower layers, the center of the variable magnetic magnet 3 Since the magnetization of the portion can be reliably performed, the amount of change in the linkage flux can be increased. That is, the amount of flux linkage when the variable magnetic magnet 3 is irreversibly changed by the d-axis current can be the total flux linkage of the variable magnetic magnet 3 and the fixed magnetic magnets 4 and 4.

(2) The adjustment of the total interlinkage magnetic flux of the permanent magnet makes it possible to adjust the voltage of the rotating electrical machine in a wide range, and the magnetization is always weakened by performing a pulse-like current in an extremely short time. Since it is not necessary to continue the flow, loss can be greatly reduced. Further, since it is not necessary to perform the flux-weakening control as in the prior art, harmonic iron loss due to the harmonic magnetic flux does not occur. As described above, the rotating electrical machine according to the present embodiment enables high-output, wide-range variable speed operation from low speed to high speed, and high efficiency in a wide operation range.

(3) Regarding the induced voltage by the permanent magnet, the variable magnetic force magnet 3 can be magnetized with a negative d-axis current to reduce the total interlinkage magnetic flux of the permanent magnet. Therefore, the inverter electronic component is damaged by the induced voltage of the permanent magnet. And the reliability is improved.

(4) In a state where the rotating electrical machine is rotated with no load, the total magnetic flux linkage of the permanent magnet can be reduced by magnetizing the variable magnetic force magnet 3 with a negative d-axis current. As a result, the induced voltage is remarkably lowered, and there is almost no need to constantly apply a weak magnetic flux current for lowering the induced voltage, thereby improving the overall efficiency. In particular, when the rotating electric machine of the present embodiment is mounted on a commuter train that has a long coasting operation time, the overall driving efficiency is greatly improved.

(2. Second Embodiment)
(2-1. Configuration)
A second embodiment of the present invention will be described with reference to FIG.

  The configuration of the second embodiment of the present invention is obtained by changing the type of permanent magnet to be laminated as the variable magnetic magnet 3 of the first embodiment. That is, instead of the variable magnetic force magnets 3a to 3c of the first embodiment, the variable magnetic force magnet 3a having a strong coercive force is disposed in the upper layer portion, and the variable magnetic force magnet 3b having a coercive force weaker than the variable magnetic force magnet 3a is disposed in the middle layer portion. The fixed magnetic magnet 4 ′ having a coercive force 3 to 5 times that of the variable magnetic magnet 3a is arranged in the lower layer portion. A composite magnet is used.

  That is, the magnetization directions of the variable magnetic force magnets 3a and 3b and the fixed magnetic force magnet 4 'are the same and are magnetically arranged in series. On the other hand, the fixed magnetic magnets 4 and 4 are arranged on both sides of a magnet in which the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 'are stacked in series at positions where the magnetization direction is the d-axis direction. The fixed magnetic magnets 4 and 4 arranged on the side form a parallel circuit on the magnetic circuit with respect to the magnets stacked in series. That is, on the magnetic circuit, the fixed magnetic magnet 4 'is arranged in series with the variable magnetic magnets 3a and 3b, and the fixed magnetic magnets 4 and 4 are arranged in parallel. The variable magnetic magnets 3a and 3b can be samarium cobalt magnets or alnico magnets, and the fixed magnetic magnets 4 and 4 'can be NdFeB magnets. Further, the coercive force of each magnet is set equal to that in the first embodiment.

(2-2. Action of series arrangement)
In the present embodiment, since the plurality of magnets are magnetically arranged in series, the composite magnet has an action different from that of the permanent magnet type rotating electrical machine of Patent Document 1 when demagnetizing and magnetizing the composite magnet. This point will be described with reference to FIGS.

  FIG. 7 is a diagram when the maximum amount of flux linkage before demagnetization is obtained. In this case, since the magnetization directions of the two types of variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 'are the same, the magnetic fluxes of the three permanent magnets 3a, 3b and 4' are added together to obtain the maximum amount of magnetic flux. Is obtained.

  FIG. 8 shows a state at the time of demagnetization, and a magnetic field in the opposite direction to the magnetization direction of the two types of variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 'is generated from the d-axis direction by the armature winding. A negative d-axis current is applied to the armature winding in a pulse manner. If the magnetic field in the magnet changed by the negative d-axis current becomes 350 kA / m, the coercive force of the variable magnetic magnet 3a having a strong coercive force is 300 kA / m, and the magnetic force of the variable magnetic magnets 3a and 3b is irreversibly large. To drop. In this case, the magnetic field from the fixed magnetic magnet 4 'laminated thereon is applied to the variable magnetic magnets 3a and 3b. Since this cancels out the magnetic field applied from the d-axis direction for demagnetization, a larger magnetizing current is required, but the magnetizing current for demagnetization is smaller than that at the time of demagnetization. There is little increase in magnetizing current.

  FIG. 9 shows a state in which the magnetic forces of the variable magnetic magnets 3a and 3b in a reverse magnetic field are reduced by a negative d-axis current. Although the magnetic force of the variable magnetic magnet 3 is irreversibly significantly reduced, the magnetic force is not irreversibly lowered because the coercive force of the fixed magnetic magnet 4 'is 1000 kA / m. As a result, when the pulsed d-axis current becomes 0, only the variable magnetic force magnets 3a and 3b are demagnetized, and the amount of interlinkage magnetic flux by the entire magnet can be reduced.

  FIG. 10 shows a state in which the magnetic force of the variable magnetic force magnets 3a and 3b in the reverse magnetic field is magnetized in the reverse direction by the negative d-axis current, and the linkage flux by the entire magnet is minimized. If a magnetic field of 350 kA / m necessary for magnetizing the variable magnetic magnet 3a having a negative d-axis current magnitude is generated, the demagnetized variable magnetic magnet 3a is magnetized to generate a magnetic force. appear. At this time, the magnetic field applied to the central portion of the composite magnet is 350 kA / m or less. However, the coercive force of the variable magnetic magnet 3b disposed in the center is 200 kA / m, and the strength of the magnetic field required for magnetization is also low, so the variable magnetic magnet 3b is also magnetized to generate a magnetic force. In this case, since the magnetization directions of the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 'are opposite, the magnetic fluxes of both permanent magnets are subtracted to minimize the magnetic flux.

  FIG. 11 shows a state in which a magnetic field is generated in order to reduce the magnetic force of the variable magnetic magnets 3a and 3b whose polarity is reversed by a negative d-axis current. A positive d-axis current that generates a magnetic field in the magnetization direction of the fixed magnetic magnet 4 ′ is applied in a pulse manner to the armature winding. The magnetic force of the variable magnetic force magnets 3a and 3b in which the polarity of the magnetic field in the magnet changed by the positive d-axis current is reversed is irreversibly greatly reduced. In this case, the magnetic field from the fixed magnetic magnet 4 ′ stacked on the variable magnetic magnet 3 is added to the magnetic field generated by the magnetizing current (a biased magnetic field acts on the variable magnetic magnet 3 from the fixed magnetic magnet 4 ′). Therefore, the demagnetization of the variable magnetic force magnets 3a and 3b is easily performed.

  FIG. 12 shows a state in which the magnetic force of the variable magnetic magnets 3a and 3b whose polarity is reversed by a magnetic field due to a positive d-axis current is reduced. The magnetic field generated by the fixed magnetic force magnet 4 'is also added to the magnetic field generated by the positive d-axis current that irreversibly decreases the magnetic force of the variable magnetic force magnet 3. Therefore, even when a large magnetizing current is usually required, an increase in the magnetizing current can be suppressed by the action of the fixed magnetic magnet 4 '.

  FIG. 13 shows a state in which the variable magnetic force magnets 3a and 3b are magnetized in the reverse direction (polarity is reversed again) by the positive d-axis current, and the linkage flux of the entire magnet is maximized. Since the magnetization directions of the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 'are the same, the magnetic fluxes of both permanent magnets are added together to obtain the maximum amount of magnetic flux.

(2-3. Action of variable magnetic magnet)
Next, the operation of the variable magnetic force magnet 3 will be described. FIG. 14 is a graph showing magnetic characteristics (relationship between coercive force and magnetic flux density) of typical magnets such as NdFeB magnet and alnico magnet and samarium cobalt magnets having coercive forces of 300 kA / m and 200 kA / m. . In the present embodiment, NdFeB magnets are used as the fixed magnetic magnets 4 and 4 ', and samarium cobalt magnets having coercive forces of 300 kA / m and 200 kA / m are used as the variable magnetic magnets 3a to 3c.

  The variable magnetic force magnets 3a and 3b have a high magnetic flux density when only the variable magnetic force magnets 3a and 3b are in a state of low coercive force, but in the state where the fixed magnetic force magnets 4 are arranged in parallel, The operating point of the variable magnetic magnets 3a and 3b is lowered, and the magnetic flux density is lowered. On the other hand, in the state where the variable magnetic magnet 3 and the fixed magnetic magnet 4 ′ are stacked in series, the operating point of the magnet of the variable magnetic magnet 3 rises due to the action of the fixed magnetic magnet 4 ′ stacked in series, and the magnetic flux Density increases.

  That is, the operating points of the variable magnetic force magnets 3a and 3b, which are low coercive force and high magnetic flux density magnets, are on the high magnetic flux density side (A and B in FIG. 14) when only the variable magnetic force magnets 3a and 3b are present. In a state where the fixed magnetic magnets 4 and 4 are arranged in parallel, the magnetic flux density decreases to the low magnetic flux density side (A ′ and B ′ in FIG. 14). However, in the state where the variable magnetic magnet 3 and the fixed magnetic magnet 4 ′ are stacked in series as in the present embodiment, the fixed magnetic magnets 4 and 4 arranged in parallel and the fixed magnetic magnet 4 arranged in series. Since the direction of the magnetic field 'is opposite, both magnetic fields cancel each other, and the operating point of the variable magnetic force magnet 3 moves to the high magnetic flux density side (A ″, B ″ in FIG. 14).

  As can be seen from this graph, when the variable magnetic force magnets 3a and 3b are used singly, in order to lower the magnetic flux density from the operating points A and B, the magnetic force sufficient to overcome the coercive force is used. Therefore, a large d-axis current is required. However, as in the present embodiment, the operating point of the variable magnetic force magnet 3 is moved to A ″ in the figure by the fixed magnetic force magnets 4 and 4 arranged in parallel and the fixed magnetic force magnet 4 ′ arranged in series. Therefore, the magnetic flux density is drastically reduced by slightly changing the strength of the magnetic field, so that the magnetic force of the variable magnetic force magnet 3 is reversed by the d-axis current of the armature winding. When it decreases, the change in the magnetic flux density can be increased, so that the amount of interlinkage magnetic flux by the entire permanent magnet disposed in the magnetic pole can be greatly changed with a small d-axis current.

  The alnico magnet is also a variable magnet having a low magnetic coercive force of 150 kA / m and a high magnetic flux density, which has the same magnetic flux characteristics as the samarium cobalt magnet. Therefore, as the variable magnetic magnet 3, when the variable magnetic magnets 3a to 3c are laminated in three layers, or when the variable magnetic magnets 3a, 3b and the fixed magnetic magnet 4 ′ are laminated, the variable magnetic magnet 3b is used as the middle variable magnetic magnet 3b. Can do. Even when an alnico magnet is used as the variable magnetic force magnet 3b, the magnetic flux density is drastically lowered only by slightly changing the strength of the magnetic field.

(2-4. Effect)
In the present embodiment having the configuration and operation as described above, the following effects can be obtained.
(1) Since the operating point on the magnetic characteristics of the variable magnetic force magnet can be changed from a high position to a low position, the total flux linkage of the permanent magnet can be changed in a wide range. Further, even if the magnetic field applied to the central portion of the variable magnetic force magnet 3 by the d-axis current is weaker than that of the upper layer portion and the lower layer portion, the central portion of the variable magnetic force magnet 3 can be surely magnetized. The amount of change can be increased. That is, the amount of flux linkage when the variable magnetic magnet 3 is irreversibly changed by the d-axis current is the total linkage of the variable magnetic magnets 3a, 3b, the fixed magnetic magnet 4 ', and the fixed magnetic magnets 4, 4. It can be the amount of magnetic flux.
(2) Since the increase in magnetizing current at the time of magnetizing can be suppressed, it is not necessary to increase the size of the inverter for driving the permanent magnet type rotating electrical machine, and the current inverter can be used as it is to improve the operation efficiency. It becomes.
(3) In the state where the total interlinkage magnetic flux of the permanent magnet of this rotating electrical machine is maximized, the operating point on the magnetic characteristics of the variable magnetic force magnet can be increased (the magnetic flux density is increased). Since it can be increased, the maximum torque can be increased.

(3. Third embodiment)
A third embodiment of the present invention will be described with reference to FIG.
In the present embodiment, as shown in FIG. 15, one fixed magnetic magnet 4 is positioned at the position where the magnetization direction is the d-axis direction (here, substantially the radial direction of the rotor) (the magnetic pole central axis of the rotor). In the rotor core 2. On the other hand, composite magnets in which the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 ′ are stacked in series are arranged on both sides of the fixed magnetic magnet 4 at positions where the magnetization direction is the d-axis direction. The composite magnet in which the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 ′ disposed on both sides are laminated forms a parallel circuit on the magnetic circuit with respect to the fixed magnetic magnet 4 at the magnetic pole center.

  The coercive force of each magnet constituting the composite magnet and the fixed magnetic magnet is the same as that of the second embodiment.

  In the present embodiment having the above-described configuration, in addition to the same effect as the above-described embodiment, a magnet in which the variable magnetic magnets 3a and 3b and the fixed magnetic magnet 4 ′ are stacked on the left and right with respect to the magnetic pole is provided. Since they are arranged, the variable magnetic magnet 3 can be magnetized by dividing the left and right sides twice. As a result, there is only one fixed magnetic magnet 4 arranged in parallel that will prevent the polarity change of the variable magnetic magnets 3a, 3b. That is, compared to the embodiment in which two fixed magnetic magnets 4 are arranged, the magnetic field by the fixed magnetic magnet 4 that prevents the change in polarity of the variable magnetic magnet 3 can be reduced, so that the magnetic force of the variable magnetic magnet 3 can be changed. The required magnetizing current (d-axis current) can be reduced.

Also, in special winding structures, such as concentrated windings and fractional groove windings, the stator and rotor geometric positions are shifted for each magnetic pole. Thus, the variable magnetic magnet 3 can be magnetized.
(4. Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG.
In the present embodiment, as shown in FIG. 16, the fixed magnetic magnets 4b and 4b are arranged on both sides of the variable magnetic magnets 3a to 3c used in the first embodiment to constitute the first magnetic pole of the rotor. On the other hand, a fixed magnetic force magnet 4a is disposed adjacent to the first magnetic pole to constitute a second magnetic pole. The polarities of the fixed magnetic magnets 4a and 4b in the adjacent first and second magnetic poles are arranged to have different polarities on the outer peripheral side and the inner peripheral side of the rotor.

  That is, the first magnetic pole in which the fixed magnetic magnets 4b and 4b are arranged on both sides of the variable magnetic magnets 3a to 3c and the fixed magnetic magnets 4b and 4b in the first magnetic pole are arranged on both sides of the first magnetic pole. The magnetic pole of the rotor is formed from the second magnetic pole configured using the fixed magnetic magnets 4a having different polarities. In the first magnetic pole, the variable magnetic force magnets 3a to 3c and the fixed magnetic force magnets 4b and 4b are arranged in parallel on the magnetic circuit, and are arranged on the variable magnetic force magnets 3a to 3c of the first magnetic pole and the second magnetic pole. The fixed fixed magnets 4a are arranged in series on the magnetic circuit.

  In the present embodiment having the above configuration, the variable magnetic force magnets 3a to 3c are not arranged in series with the fixed magnetic force magnet in one pole of the rotor. However, since the variable magnetic magnets 3a to 3c are affected by the magnetic field of the adjacent fixed magnetic magnet 4a, it is possible to obtain the same effect as when the fixed magnetic magnet 4a is stacked as in the above embodiment. That is, the magnetic field of the fixed magnetic magnet 4a at the pole of the adjacent rotor is opposite to the magnetic field of the fixed magnetic magnets 4b and 4b arranged in parallel to the variable magnetic magnets 3a to 3c in the variable magnetic magnet 3. And act to offset each other. As a result, when the variable magnetic magnets 3a to 3c are magnetized from the irreversibly demagnetized state and returned to the original polarity, the magnetic field generated by the adjacent fixed magnetic magnets 4b and 4b that hinders the change can be reduced. Magnetization current (d-axis current) required when changing the magnetic force of the magnetic magnets 3a to 3c can be reduced.

  Also in the present embodiment, since a strong magnetic field acts on the upper layer portion and the lower layer portion of the variable magnetic force magnet 3 by the d-axis current, the variable magnetic force magnets 3a and 3c having a coercive force of 300 kA / m can be magnetized. On the other hand, a weak magnetic field acts on the central portion of the variable magnetic force magnet 3, but the variable magnetic force magnet 3b arranged in the middle layer portion can be sufficiently magnetized because the coercive force is as small as 200 kA / m.

(5. Other embodiments)
The present invention is not limited to the above-described embodiments, and includes other embodiments as follows.

(1) The variable magnetic magnet is a composite magnet in which three layers of variable magnetic magnets having different coercive force or two layers of variable magnetic magnets having different coercive force and one layer of fixed magnetic magnet are stacked. However, the present invention is not limited to this, and the number of layers may be four or more. In addition, when the strength of the magnetic flux applied to the variable magnetic force magnet is adjusted by the arrangement of the magnetic barrier and the short-circuit coil, the variable magnetic force magnet having a strong coercive force and the variable magnetic force magnet having a low coercive force are adjusted in accordance with the adjusted strength. It is also possible to change the arrangement according to the intensity of the magnetic flux applied to the variable magnetic magnet.

(2) As the variable magnetic magnet having a weak coercive force, a ferrite magnet can be used in addition to the samarium cobalt magnet and the alnico magnet having a weak coercive force described in the embodiment. Further, a NdFeB magnet having a low coercive force and other low coercive force magnets can be applied.

(3) In each of the above embodiments, a four-pole rotating electric machine is shown, but the present invention is naturally applicable to a multi-pole rotating electric machine such as an eight-pole machine. Depending on the number of poles, the position and shape of the permanent magnets will of course change somewhat, and the action and effect can be obtained in the same way.

(4) In the permanent magnet forming the magnetic pole, the permanent magnet is defined to be distinguished by the product of the coercive force and the thickness in the magnetization direction. Therefore, even if the magnetic poles are formed of the same type of permanent magnet and are formed so as to have different magnetization direction thicknesses, the same operation and effect can be obtained.

(5) In the rotor core 2, in order to determine the shape and position of the cavity provided to form the magnetic barrier on the outer peripheral side of the fixed magnetic magnet, and the magnetic path cross-sectional area on the inner peripheral side of the fixed magnetic magnet The position of the cavity provided in can be appropriately changed according to the coercive force of the permanent magnet used, the strength of the magnetic field generated by the magnetizing current, and the like.

(6) During operation, the permanent magnet is magnetized by a magnetic field generated by a pulsed d-axis current for a very short time, and the amount of magnetic flux of the permanent magnet is irreversibly changed, and the phase is advanced with respect to the induced voltage of all the magnets. By continuously energizing the current, the amount of interlinkage magnetic flux of the armature winding generated by the current and the permanent magnet is changed.

  That is, if the amount of magnetic flux of the permanent magnet is reduced by the pulse current and the current phase is further advanced, magnetic flux generated by the current in the opposite direction to the magnetic flux is generated. Terminal voltage can be reduced. Note that advancing the current phase is equivalent to flowing a negative d-axis current component.

  In such current phase advance control, when the current phase is advanced, a d-axis current flows, the magnet is demagnetized, and the amount of magnetic flux is somewhat reduced. However, since the magnetic field is greatly demagnetized by the pulse current, there is an advantage that the reduction of the magnetic flux amount is small in proportion.

(7) When assembling the rotor by inserting it into the stator, demagnetize the permanent magnet whose product of coercive force and magnetization direction thickness is small, or reduce the flux linkage of the permanent magnet by reversing the polarity. State. Thereby, assembly work can be easily performed.

Sectional drawing of the rotor and stator in the 1st Embodiment of this invention Sectional view showing magnetic field distribution when magnetizing variable magnetic magnet in rotor Sectional drawing which shows the state at the time of demagnetization in 1st Embodiment Sectional drawing which shows the relationship between the magnetic barrier in this invention, and q-axis magnetic flux Sectional drawing which shows the effect | action of the short circuit coil in this invention Sectional drawing of the rotor and stator in the 2nd Embodiment of this invention Sectional drawing which shows the state with the largest flux linkage of the magnet of 2nd implementation Sectional drawing which shows the state which generated the magnetic field which reduces the magnetic force of a variable magnetic force magnet with the electric current of the coil of 2nd implementation Sectional drawing which shows the state where the magnetic force of the variable magnetic force magnet decreased with the reverse magnetic field by the electric current of 2nd implementation Sectional drawing which shows the state where a variable magnetic force magnet is magnetized in the reverse direction by the reverse magnetic field by the electric current of 2nd implementation, and the linkage flux of a magnet is the minimum Sectional drawing which shows the state which generate | occur | produced the magnetic field which reduces the magnetic force of the variable magnetic magnet which reversed the polarity with the electric current of the coil of 2nd implementation Sectional drawing which shows the state which reduced the magnetic force of the variable magnetic magnet which reversed the polarity with the magnetic field by 2nd implementation electric current Sectional drawing which shows the state where a variable magnetic force magnet is magnetized in the reverse direction by the reverse magnetic field by the electric current of 2nd implementation, and the linkage flux of a magnet is the maximum Diagram showing operating point change of low coercivity magnet and magnetic characteristics of typical magnet The schematic diagram which shows the structure of the 3rd Embodiment of this invention. The schematic diagram which shows the structure of the 4th Embodiment of this invention. Sectional view of rotor described in Patent Document 1 Schematic diagram showing the action of the rotor described in Patent Document 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Rotor core 3, 3a-3c ... Variable magnetic magnet 4, 4 ', 4a, 4b ... Fixed magnetic magnet 5 ... Cavity (magnetic barrier)
6. Cavity at the end of permanent magnet (magnetic barrier)
7: Magnetic pole portions 8a, 8b ... Short-circuit coil

Claims (18)

The magnetic poles of the rotor are formed by using two or more types of permanent magnets having a product of the coercive force and the magnetization direction thickness different from those of other permanent magnets, and the two or more types of permanent magnets are generated by the magnetic field generated by the current of the armature winding. Among them, in a permanent magnet rotating electrical machine that magnetizes a permanent magnet having a small product of coercive force and magnetization direction thickness and irreversibly changes the amount of magnetic flux of the permanent magnet constituting the magnetic pole,
Permanent magnets with a small product of coercive force and magnetization direction thickness, which are magnetized by the magnetic field generated by the current generated by the armature winding, are laminated with a plurality of permanent magnets with different values of the product of coercive force and magnetization direction thickness. Configure
The product of the coercive force and the magnetization direction thickness of the permanent magnet located in the center of the composite magnet is the product of the product of the coercivity and the magnetization direction thickness of the permanent magnet located in at least one of the upper layer or the lower layer of the composite magnet. A permanent magnet type rotating electrical machine characterized by being set smaller than the value. The composite magnet is formed by laminating at least three layers of permanent magnets having a small product of coercive force and magnetization direction thickness.
The product of the coercive force and magnetization direction thickness of the permanent magnet located in the center of the composite magnet is set smaller than the product of the coercivity and magnetization direction thickness of the permanent magnet located in the upper and lower layers of the composite magnet. The permanent magnet type rotating electrical machine according to claim 1, wherein: A permanent magnet having a large product of coercive force and magnetization direction thickness is laminated to the composite magnet,
The value of the product of the coercive force and the magnetization direction thickness of the permanent magnet located at the center of the composite magnet is set to be smaller than the product of the coercivity and the magnetization direction thickness of the other permanent magnets of the composite magnet. The permanent magnet type rotating electrical machine according to claim 1, wherein In the same magnetic pole of the rotor, the composite magnet and a permanent magnet having a large product of coercive force and magnetization direction thickness are arranged in series and in parallel on the magnetic circuit,
The permanent magnet type rotating electric machine according to any one of claims 1 to 3, wherein a permanent magnet having a large product of a coercive force and a magnetization direction thickness is disposed between the magnetic poles of the composite magnet. In the same magnetic pole of the rotor, the composite magnet and a permanent magnet having a large product of coercive force and magnetization direction thickness are arranged in series and in parallel on the magnetic circuit,
The permanent magnet having a large product of the coercive force and the magnetization direction thickness is disposed at the center of the magnetic pole, and the composite magnet is disposed between the magnetic poles. The permanent magnet type rotating electrical machine described in 1. The rotor magnetic pole is composed of a magnetic pole composed of a magnet having a large product of coercive force and magnetization direction thickness, and a magnetic pole composed of the composite magnet and a magnet having a large product of coercive force and magnetization direction thickness. And
A magnetic pole permanent magnet composed of a magnet having a large product of coercive force and magnetization direction thickness, and a composite magnet of magnetic pole composed of the composite magnet and a magnet having a large product of coercive force and magnetization direction thickness are magnetized. The permanent magnet type rotating electrical machine according to any one of claims 1 to 3, wherein the permanent magnet type rotating electrical machine is connected in series in a circuit.   The composite magnet is magnetized by the magnetic field generated by the current of the armature winding to irreversibly decrease the flux linkage by the permanent magnet, and after the decrease, the magnetic field by the current is generated in the opposite direction to magnetize the composite magnet. The permanent magnet type rotating electrical machine according to any one of claims 1 to 6, wherein the amount of flux linkage is irreversibly increased.   The composite magnet is magnetized by a magnetic field generated by a d-axis current to change the amount of magnetic flux irreversibly, and a d-axis current for magnetizing the composite magnet is supplied, and at the same time, torque is controlled by a q-axis current. The permanent magnet type rotating electrical machine according to claim 1.   The operation of irreversibly changing the amount of magnetic flux of the permanent magnet by magnetizing the composite magnet with the magnetic field due to the d-axis current during operation, the amount of flux linkage between the current and the armature winding generated by the permanent magnet by the magnetic flux generated by the d-axis current The permanent magnet type rotating electrical machine according to any one of claims 1 to 8, wherein the permanent magnet rotating electric machine has an operation of changing in a substantially reversible manner.   At maximum torque, the composite magnet is magnetized so that the total interlinkage magnetic flux of the permanent magnet is large, and the magnet is magnetized by a magnetic field due to current at light loads with small torque and at medium and high speed rotation ranges. The permanent magnet type rotating electrical machine according to any one of claims 1 to 9, wherein the interlinkage magnetic flux of the permanent magnet is reduced.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 10, wherein the magnets arranged in parallel on the magnetic circuit are arranged substantially on a straight line or on a V-shape.   The magnet arranged in parallel on the magnetic circuit is composed of a magnet arranged substantially on the q-axis of the side surface of the magnetic pole and a magnet arranged in the center of the magnetic pole. 11. The permanent magnet type rotating electrical machine according to any one of 11 above.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 12, wherein a portion in which a magnetic resistance is increased is provided in a magnetic path of a magnet having a large product of a coercive force and a magnetization direction thickness. .   The short-circuit coil is provided in a direction perpendicular to the magnetization direction of a permanent magnet having a large product of the coercive force and the magnetization direction thickness provided in the rotor. The permanent magnet type rotating electrical machine described in 1.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 14, wherein a magnetoresistance in the q-axis direction is larger than a magnetoresistance in the q-axis direction excluding the magnet portion.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 15, wherein an air gap length in the q-axis direction is larger than an air gap length in the d-axis direction.   When the rotor reaches the maximum rotation speed with the magnetic flux linkage minimized by irreversibly changing the magnetic pole magnet, the induced electromotive force of the permanent magnet is less than the withstand voltage of the inverter electronic component that is the power supply of the rotating electrical machine The permanent magnet type rotating electric machine according to any one of claims 1 to 16, wherein:   When assembling the rotor into the stator, the permanent magnet with a small product of the coercive force and the magnetization direction thickness is demagnetized or the interlinkage magnetic flux of the permanent magnet is reduced by reversing the polarity. The permanent magnet type rotating electrical machine according to any one of claims 1 to 17, wherein the permanent magnet type rotating electrical machine is provided.