JP2010004671A - Permanent magnet type electric rotating machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a permanent magnet type electric rotating machine capable of variable operation ranging from low speed to high speed with high output, by suppressing increase in the magnetization current, when magnetization increases. <P>SOLUTION: A rotor 1 includes a rotor core 2, a permanent magnet 3 having a small product of a coercive force and a magnetization direction thickness, and a permanent magnet 4, having a large product of a coercive force and a magnetization direction thickness. The rotor core 2 is configured by stacking silicon steel plates, and the permanent magnets 3, 4 are embedded in the rotor core 2. Cavities 5 are provided at the ends of the permanent magnets 3, 4 so that a magnetic flux passing through the inside of the rotor core 2 pass the permanent magnets 3, 4 in their thickness directions. When an interlinkage magnetic flux of the permanent magnet 3 is reduced, a magnetic field having a direction reverse to that of the magnetization direction of the permanent magnet 3 is allowed to act by a current of an armature winding. When the interlinkage magnetic flux of the permanent magnet 3 is increased, the magnetic flux of the direction which is identical to that of the magnet magnetization direction is made to act by the current of the armature winding. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention uses two or more types of permanent magnets arranged in series magnetically, and irreversibly changes the amount of magnetic flux of at least one of the permanent magnets, so that the variable speed can be varied over a wide range from low speed to high speed. The present invention relates to a permanent magnet type rotating electrical machine that can be operated.

  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 at a constant value, 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 operate at a variable speed of more than 3 times the base speed. 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. In addition, there is a possibility that vibration is generated by electromagnetic force generated by harmonic magnetic east.

  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 techniques for solving such problems, Patent Document 1 and Patent Document 2 describe a permanent magnet having a low coercive force so that a magnetic flux density is irreversibly changed by a magnetic field generated by a current of a stator winding, A high coercivity permanent magnet with a coercive force more than twice that of the coercive permanent magnet is arranged, and in the high-speed rotation range where the power supply voltage exceeds the maximum voltage, all of the low coercivity permanent magnet and the high coercive force permanent magnet are used. A technique for adjusting the total amount of interlinkage magnetic flux by magnetizing a permanent magnet with a low coercive force with a magnetic field by current so that the interlinkage magnetic flux is reduced is described.

  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 low coercivity permanent magnets 3, and eight high coercivity permanent magnets 4. The rotor core 2 is configured by laminating silicon steel plates, the low coercivity permanent magnet 3 is an alnico magnet or an FeCrCo magnet, and the high coercivity magnet 4 is an NdFeB magnet.

  The low coercivity permanent magnet 3 is embedded in the rotor core 2, and first cavities 5 are provided at both ends of the low coercivity permanent magnet 3. The low coercive force permanent 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 high coercivity permanent magnet 4 is embedded in the rotor core 2, and second cavities 6 are provided at both ends of the high coercivity permanent magnet 4. The high coercive force permanent magnet 4 is disposed substantially in the circumferential direction of the rotor 1 so as to be sandwiched between the two low coercive force permanent magnets 3 on the inner peripheral side of the rotor 1. The high coercive force permanent 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 low coercivity permanent magnets 3 and one high coercivity permanent 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) through the stator windings, A magnetic field is applied to the coercive force permanent magnet 3. When the magnetizing magnetic field is 250 kA / m, ideally, a sufficient magnetizing magnetic field acts on the low coercive force permanent magnet 3, and the high coercive force permanent 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 low coercive force permanent 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 both forward and reverse. Can be. That is, assuming that the linkage flux of the high coercivity permanent magnet 4 is the positive direction, the linkage flux of the low coercivity permanent magnet 3 can be adjusted over a wide range from the maximum value in the positive direction to 0, and further to the maximum value in the reverse direction. it can. Therefore, in the rotor of the present embodiment, the total amount of interlinkage magnetic flux combining the low coercivity permanent magnet 3 and the high coercivity permanent magnet 4 is widened by magnetizing the low coercivity permanent magnet 3 with the d-axis current. Can be adjusted.

For example, in the low speed region, the low coercive force permanent magnet 3 is magnetized with the d-axis current so that the maximum value is obtained in the same direction (initial state) as the interlinkage magnetic flux of the high coercive force permanent magnet 4, so that the torque by the permanent magnet is maximized. Therefore, the torque and output of the rotating electrical machine can be maximized. In the middle and high speed range, the voltage of the rotating electrical machine is lowered by reducing the amount of magnetic flux of the low coercivity permanent magnet 3 and reducing the amount of interlinkage magnetic flux. The speed (frequency) can be further increased.
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 low coercive force permanent magnet 3 can be greatly changed from the maximum to 0 by the d-axis current of the rotor 1, and the magnetization direction Also has an excellent characteristic that it can be made in both forward and reverse directions. On the other hand, when magnetizing the low coercive force permanent magnet 3, a large magnetizing current is required, leading to an increase in the size of the inverter for driving the electric motor.

  In particular, due to the characteristics of the permanent magnet, a large magnetizing current is required when the magnet is increased than when the magnet is demagnetized. However, in the permanent magnet type rotating electrical machine disclosed in Patent Document 1, two types of magnets are magnetically arranged in parallel. Due to the configuration, a large magnetic field is required for magnetizing the low coercivity permanent magnet 3 due to the influence of the linkage flux of the high coercivity permanent magnet 4.

  FIGS. 8A to 8D are schematic diagrams for explaining this. In the permanent magnet type rotating electric machine of Patent Document 1, as shown in FIG. 8A, two low coercive force permanent magnets 3 and one high coercive force permanent magnet 4 are arranged in a U shape with the d axis as the center. Yes. In the normal operation state of the electric motor, the direction of the magnetic flux of each permanent magnet 3, 4 is directed toward the central magnetic pole part 7. In this state, when a d-axis current is applied in a pulsed manner to generate a demagnetizing magnetic field, the magnetic flux penetrates the permanent magnets 3 and 4 from the outer peripheral side of the rotor 1 as shown in FIG. Thus, the low coercive force permanent magnet 3 is demagnetized. At this time, since the high coercive force permanent magnet 4 has a high coercive force, it is not demagnetized.

  In the case of this demagnetization, as shown in FIG. 8C, the magnetic flux of the high coercivity permanent magnet 4 is the initial value of the low coercivity permanent magnet 3 from the inside to the outside of the low coercivity permanent magnet 3 along with the d-axis direction. Flows in the direction opposite to the direction of the magnetic flux, so that the demagnetizing action by the magnetic field generated by the d-axis current is assisted. Therefore, demagnetization until the polarity of the low coercive force permanent magnet 3 is reversed is possible.

  On the other hand, in the case of magnetization, a low coercive force is generated by applying a d-axis current again in a pulsed manner to generate a magnetic field in the opposite direction to that described above and demagnetizing by the reverse magnetic flux constituting the magnetic field. The interlinkage magnetic flux of the permanent magnet 3 is returned to the state during normal operation of (A). However, originally, a larger energy is required for magnetizing than demagnetization, and the magnetic flux of the high coercivity permanent magnet 4 is demagnetized in the low coercivity permanent magnet 3 as shown in FIG. Therefore, a magnetizing current capable of generating a large magnetic field that can overcome this is required.

  Thus, since the permanent magnet type rotating electrical machine of Patent Document 1 has two kinds of magnets arranged in parallel magnetically, the amount of demagnetization of the low coercive force permanent magnet 3 can be increased, and the change width of the magnetic force can be increased. Although there is an advantage that it can be increased to 0 to 100%, there is a problem that a large magnetization current is required at the time of magnetization.

  On the other hand, a change in the amount of interlinkage magnetic flux as in the permanent magnet type rotating electrical machine of Patent Document 1 is not required, but the technique as in Patent Document 1 should be applied to an application where it is desired to avoid increasing the size of the inverter as much as possible. Is expected. For example, when the change width of the linkage flux is in the range of 70 to 100%, the inverter is used as it is for the current electric motor.

  The present invention has been made to solve the above-described problems, and reduces the magnetizing current at the time of magnetizing the low coercive force permanent magnet, thereby reducing the speed of the inverter without increasing the size of the inverter. It is an object of the present invention to provide a permanent magnet type rotating electrical machine that can be operated at a variable speed in a wide range up to a high torque in a low speed rotation region, a high output in a medium / high speed rotation region, and an efficiency improvement.

  In order to achieve the above object, the permanent magnet type rotating electrical machine according to the present invention has two or more kinds of permanent magnets having a product of a coercive force and a magnetization direction thickness different from those of other permanent magnets so as to be magnetically in series. The magnetic poles are formed, and the magnetic poles are arranged in the rotor core to constitute the rotor, and the stator is arranged on the outer periphery of the rotor via an air gap, and the armature core and the electric machine are arranged on the stator. A coil is provided, and at least one of the permanent magnets constituting the magnetic pole of the rotor is magnetized by a magnetic field generated by the current of the armature coil, and the amount of magnetic flux of the permanent magnet is irreversibly changed. And

  In particular, when reducing the flux linkage of the permanent magnet, the permanent magnet having a smaller product of the coercive force and the magnetization direction thickness than the other permanent magnets, When the magnetic flux in the reverse direction is applied to change the magnetic flux irreversibly to increase the flux linkage of the permanent magnet, the magnet magnetization caused by the armature winding current is applied to the permanent magnet having a small product of the coercive force and the magnetization direction thickness. It is preferable to change irreversibly by applying a magnetic field in the same direction as the direction.

  As described above, in the present invention, two or more kinds of permanent magnets having a product of coercive force and magnetization direction thickness different from those of other permanent magnets are arranged so as to be magnetically in series. When increasing, a magnetic field in the same direction as the magnet magnetization direction due to the current of the armature winding is applied to a permanent magnet having a small product of the coercive force and the magnetization direction thickness, and the product of the coercive force and the magnetization direction thickness is large. The magnetic field of the permanent magnet can also be applied to the magnetization direction of the permanent magnet having a small product of the coercive force and the magnetization direction thickness, thereby suppressing an increase in magnetization current.

  In addition, a permanent magnet for irreversibly changing the magnetic characteristics is arranged so that a biased magnetic field acts from another permanent magnet, two or more kinds of permanent magnets constituting the magnetic pole are arranged in an overlapping manner, and the magnetic pole is constituted. Arranging two or more kinds of permanent magnets so that the magnetization direction is substantially in the d-axis direction, arranging two or more kinds of permanent magnets constituting the magnetic pole in a V-shape or U-shape, and constituting the magnetic pole 2 It is also an aspect of the present invention to arrange more than one kind of permanent magnets in the vicinity of the q axis so that the magnetization direction is substantially the circumferential direction.

  Further, two or more kinds of permanent magnets constituting the magnetic pole are arranged with the magnetic part sandwiched therebetween, the magnetic resistance in the q-axis direction is made larger than the magnetic resistance in the q-axis direction excluding the magnet part, q-axis direction It is also an embodiment of the present invention to make the air gap length larger than the air gap length in the d-axis direction.

  According to the present invention having the above-described configuration, an increase in the magnetizing current at the time of magnetization can be suppressed, so that the efficiency of the rotating machine is achieved without increasing the size of the inverter for driving the permanent magnet type rotating electrical machine. be able to.

  Hereinafter, embodiments of a permanent magnet type rotating electrical machine according to the present invention will be described with reference to the drawings. The rotating electrical machine of the present embodiment has been described in the case of four poles, and the same applies to other pole numbers. In addition, the same code | symbol is attached | subjected about the part same as the permanent magnet type rotary electric machine shown in the said FIG. 7, and the overlapping description is abbreviate | omitted.

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

  As shown in FIG. 1, the rotor 1 according to the first embodiment of the present invention includes a rotor core 2, a permanent magnet 3 having a small product of coercive force and magnetization direction thickness, and a product of coercive force and magnetization direction thickness. Is made up of permanent magnets 4 that are large. The rotor core 2 is formed by laminating silicon steel plates, and the permanent magnets 3 and 4 are embedded in the rotor core 2. In this case, the cavity 5 is provided at the end of each of the permanent magnets 3 and 4 so that the magnetic flux passing through the rotor core 2 passes through these permanent magnets 3 and 4 in the thickness direction.

  In the present embodiment, the permanent magnet 3 having a small product of the coercive force and the magnetization direction thickness is an alnico magnet, and the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness is an NdFeB magnet. The magnetization directions of the alnico magnet and the NdFeB magnet are substantially radial, and the alnico magnet and the NdFeB magnet are embedded in the rotor core 2 so as to overlap in the magnetization direction. That is, the present embodiment is characterized in that the two types of permanent magnets 3 and 4 are magnetically arranged in series with the same magnetization direction.

  The coercive force of the alnico magnet is 50 kA / m, and the coercive force of the NdFeB magnet is 1000 kA / m. The thickness of the alnico magnet is the same as the thickness of the NdFeB magnet, but the thickness ratio may be changed according to the required motor characteristics.

  Further, when the rotating electrical machine is assembled by inserting the rotor 1 of the present embodiment configured as described above into the stator, the permanent magnet 3 having a small product of coercive force and magnetization direction thickness is demagnetized. It is preferable to do. That is, if a permanent magnet (variable magnetic force magnet 3) having a small product of coercive force and magnetization direction thickness is demagnetized or having a reversed polarity, a permanent magnet having a large product of coercive force and magnetization direction thickness (for fixed magnetic force) The sum of the magnetic force of the magnet 4) and the magnetic force of the variable magnetic force magnet 3 is the magnetic attractive force generated by the rotor.

  On the other hand, when the variable magnetic force magnet 3 is demagnetized, the total magnetic force decreases. Further, when the polarity of the variable magnetic force magnet 3 is reversed, the fixed magnetic force magnet 4 and the variable magnetic force magnet 3 cancel each other, so that the total magnetic force becomes small. Therefore, when the rotor is inserted into the stator when assembling the motor, if the magnetic force of the magnet of the rotor is strong, the rotor is gradually inserted while withstanding an excessive magnetic attraction force trying to suck into the stator. However, when the magnetic force of the rotor is weak as described above, the magnetic attraction force is small and the assembly becomes easy.

  For these permanent magnets 3 and 4, during operation of the permanent magnet type rotating electric machine, the permanent magnet 3 is magnetized by a magnetic field generated by a d-axis current, and the amount of magnetic flux of the permanent magnet 3 is irreversibly changed. In that case, the d-axis current for magnetizing the permanent magnet 3 is supplied, and at the same time, the torque of the rotating electrical machine is controlled by the q-axis current.

  Further, the amount of interlinkage magnetic flux in the armature winding generated between the current (total current obtained by combining the q-axis current and the d-axis current) and the permanent magnets 3 and 4 due to the magnetic flux generated by the d-axis current, The amount of interlinkage magnetic flux of the entire armature winding composed of the magnetic flux generated in the armature winding by the total current and the magnetic flux generated by two or more kinds of permanent magnets on the rotor side is reversibly changed.

  In particular, in the present embodiment, the variable magnetic permanent magnet 3 is 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. Since the polarity of the variable magnetic force magnet 3 is reversed by the d-axis current in this way, even if a negative d-axis current that reduces the terminal voltage is supplied, the variable magnetic force magnet 3 is not demagnetized but increased. It becomes a magnetic field. 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. In the present embodiment, the variable magnetic force magnet 3 It is possible to advance the phase by reversing the polarity of.

(1-2. Basic action)
Next, the operation of the present embodiment will be described.
In the present embodiment, the magnetomotive force required for magnetization is approximated by the product of the magnetic field required for magnetization and the thickness of the permanent magnet. Alnico 8 permanent magnets can be magnetized to nearly 100% in a magnetic field of 250 kA / m. The product of the magnetizing magnetic field and the magnet thickness is 250 kA / m × 3 mm × 10 ⁻³ = 750A.

On the other hand, the NdFeB magnet can be magnetized to nearly 100% with a magnetic field of 1500 kA / m. The product of the magnetizing magnetic field and the magnet thickness is 1500 kA / m × 2 mm × 10 ⁻³ = 3000A. That is, the alnico magnet 3 can be magnetized with a magnetic field of about ¼ that of the NdFeB magnet 4.

  In the present embodiment, a magnetic field is formed by applying a pulsed current having a very short energization time (about 0.1 ms to 100 ms) to the armature winding of the stator, and the magnetic field is applied to the alnico magnet 3. . The pulse current that forms the magnetic field for magnetizing the permanent magnet is the d-axis current component of the armature winding of the stator.

  Since the magnets have the same thickness, the influence of the working magnetic field can be evaluated by the coercive force. 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. If the magnetic field in the magnet changed by the negative d-axis current is 50 kA / m, the magnetic force of the alnico magnet is irreversibly significantly reduced because the coercive force of the alnico magnet is 50 kA / m. On the other hand, since the coercive force of the NdFeB magnet is 1000 kA / m, the magnetic force does not decrease irreversibly. As a result, when the pulsed d-axis current becomes zero, only the alnico magnet is demagnetized, and the amount of flux linkage 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 Alnico magnet is generated. Assuming 100 kA / m, the demagnetized Alnico magnet is magnetized to generate a maximum magnetic force. On the other hand, since the coercive force of the NdFeB magnet 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 Alnico magnet 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 Alnico magnet and the NdFeB magnet, the magnetic force of the Alnico magnet is irreversibly changed, and the total interlinkage magnetic flux of the permanent magnet is arbitrarily changed. Is possible.

  In this case, a permanent magnet whose product of coercive force and magnetization direction thickness is smaller than the others is magnetized so that the magnetic flux of the permanent magnet of the magnetic pole is added at the maximum torque of the permanent magnet type rotating electrical machine, and at a light load with a small torque In addition, in the medium-speed rotation region and the high-speed rotation region, the permanent magnet whose product of the coercive force and the magnetization direction thickness is smaller than the others is magnetized by a magnetic field caused by an electric current to reduce the magnetic flux.

  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 particular, in the present embodiment, two types of magnets are magnetically arranged in series. Therefore, when the demagnetization and magnetization of the permanent magnet 3 in which the product of the coercive force and the magnetization direction thickness is small, This has an action different from that of the permanent magnet type rotating electric machine of Patent Document 1. This point will be described with reference to FIG.

  FIG. 2A is a diagram in a case where the maximum amount of flux linkage before demagnetization is obtained. In this case, since the magnetization directions of the two types of permanent magnets 3 and 4 are the same, the magnetic fluxes of both permanent magnets are added together to obtain the maximum amount of magnetic flux.

  FIG. 2B shows a state at the time of demagnetization. A magnetic field opposite to the magnetization direction of both permanent magnets 3 and 4 acts from the d-axis direction, and the product of the coercive force and the magnetization direction thickness is obtained. The small permanent magnet 3 is demagnetized. In this case, the permanent magnet 3 having a small product of the coercive force and the magnetization direction thickness is applied with a magnetic field from the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness laminated thereon. Therefore, a large magnetizing current is required for this purpose, but the magnetizing current for demagnetization is smaller than that at the time of magnetizing. There is little increase.

  FIG. 2C shows the magnetic flux of the permanent magnets 3 and 4 after demagnetization. The permanent magnet 3 whose product of coercive force and magnetization direction thickness is small is demagnetized to near zero. On the other hand, the coercive force of the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness is not changed by the magnetic field generated by the magnetizing current. Therefore, when the permanent magnets 3 and 4 are viewed as a whole, the change width of the magnetic force is as small as the invention of Patent Document 1 that can change until the coercive force of the permanent magnet 3 is reversed.

  FIG. 2 (D) shows the state of magnetization increase of the permanent magnet 3. In this state, the magnetic field due to the d-axis current acts in the opposite direction to that at the time of demagnetization, magnetizes the permanent magnet 3 and returns it to the original magnetization direction. At this time, the magnetic field from the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness laminated on the permanent magnet 3 is added to the magnetic field due to the magnetization current (the biased magnetic field from the permanent magnet 4 is permanent). Therefore, the permanent magnet 3 can be easily magnetized. For this reason, even when magnetizing normally requiring a large magnetizing current, an increase in the magnetizing current can be suppressed by the action of the permanent magnet 4 in which the product of the coercive force and the magnetization direction thickness is large.

(1-4. Effect)
In the present embodiment having the configuration and operation as described above, the following effects can be obtained.
(1) 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.
(2) By changing the alnico magnet irreversibly with the d-axis current, the total amount of interlinkage magnetic flux combining the alnico magnet and the NdFeB magnet can be adjusted over a wide range.

(3) The adjustment of the total flux linkage of the permanent magnet makes it possible to adjust the voltage of the rotating electrical machine over a wide range, and since magnetization is performed with a pulse-like current for a very short time, a weak flux current is always applied. Loss can be greatly reduced because there is no need to continue. 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.

(4) With regard to the induced voltage by the permanent magnet, the Alnico magnet 3 can be magnetized with a negative d-axis current to reduce the total flux linkage of the permanent magnet, so that the inverter electronic components can be damaged by the induced voltage of the permanent magnet. The reliability is improved.

(5) In a state where the rotating electrical machine is rotated with no load, the total flux linkage of the permanent magnet can be reduced by magnetizing the alnico 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 rotary electric machine of the present invention is mounted on a commuter train that has a long coasting operation time, the overall driving efficiency is greatly improved.

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

  In the present embodiment, two types of permanent magnets 3 and 4 having different products of coercive force and magnetization direction thickness are bonded in the magnetization direction and embedded in a V-shaped hole provided in the rotor core 2. The permanent magnet 3 having a small product of the coercive force and the magnetization direction thickness uses a ferrite magnet or an alnico magnet. An NdFeB magnet is applied to the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness. The two types of bonded magnets are arranged in a V shape, but may be arranged in a U shape.

  In this case, the laminated permanent magnets 3 and 4 are V-shaped (or U-shaped) so that the V-shaped valley portion is positioned on the d-axis and the V-shaped end portions are positioned on the q-axis with respect to the rotor core 2. Embed it in a letter shape. The cavities 5 at both ends of the permanent magnets 3 and 4 are provided at positions that coincide with the d-axis or the q-axis so that magnetic flux does not enter the laminated permanent magnets 3 and 4 from this direction. That is, the magnetic flux from the d-axis direction enters perpendicularly to the laminated permanent magnets 3 and 4 so that the permanent magnet 3 having a small product of the coercive force and the magnetization direction thickness is effectively demagnetized and magnetized. To.

  In the present embodiment having the above-described configuration, in addition to the same effects as the above-described embodiments, the rotor cores are arranged by arranging two kinds of laminated permanent magnets 3 and 4 in a V shape. The area of the magnet that can be arranged within 2 can be made larger than that of those arranged linearly. As a result, since the magnetic flux by the permanent magnets 3 and 4 can be increased, the torque by the magnet can be increased. Furthermore, since a delta-shaped iron core is formed between the V-shaped parts, the q-axis magnetic flux passing through the delta-shaped portion increases. As a result, the reluctance torque is increased, and the total motor torque obtained by adding the torques from the magnets is also increased.

(3. Third embodiment)
A third embodiment of the present invention will be described with reference to FIG.

  This embodiment is different from the first embodiment in that two types of permanent magnets 3 and 4 having different products of coercive force and magnetization direction thickness are bonded in the magnetization direction and arranged perpendicular to the d-axis. It is the same. In addition, in the present embodiment, two types of permanent magnets 3a and 4a that are laminated in the same manner are embedded at a position near the q axis of the rotor core 2 in a direction that coincides with the q axis. Thereby, the magnetic pole part 7 of the rotor 1 becomes a structure enclosed by the concave shape by the three laminated bodies.

  In this case, the magnetization directions of the permanent magnets 3a, 4a arranged in the vicinity of the q axis are substantially circumferential (directions orthogonal to the q axis), and the center of the magnetic pole portion 7 embedded between the q axis side permanent magnets 3a, 4a is arranged. The permanent magnets 3 and 4 have the d-axis direction as the magnetization direction. Further, a cavity 5 is provided at both ends of the permanent magnets 3 and 4 at the center of the magnetic pole portion 7 and at the center of the permanent magnets 3a and 4a disposed in the vicinity of the q-axis, and demagnetization applied from the d-axis direction. Alternatively, a magnetic field for magnetizing is applied to each of the laminated magnets 3, 4 or 3a, 4a from a direction perpendicular to the surface thereof.

  In the present embodiment having such a configuration, in addition to the same effects as those of the previous embodiment, the influence of the magnetic field generated by the q-axis current that is arranged in the q-axis direction and the permanent magnets 3a and 4a generate torque. Difficult to receive and difficult to demagnetize. Therefore, the permanent magnets 3a and 4a arranged in the vicinity of the q axis can be thinned in the magnetization direction. Alternatively, the thickness of the magnet 4 having a large product of the coercive force and the magnetization direction thickness can be reduced, and the thickness of the magnet 3 having a small product of the coercive force and the magnetization direction thickness can be increased. The advantage in this case is that the change width of the total flux linkage of the permanent magnet can be increased.

(4. Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, when two types of permanent magnets 3 and 4 having different products of coercive force and magnetization direction thickness are stacked in the magnetization direction, iron or the like is interposed between the two types of permanent magnets 3 and 4. A magnetic layer 8 is provided.

  When the permanent magnets 3 and 4 are laminated as in the above-described embodiments, the magnets become magnetic resistances. Therefore, the strong magnetic field generated by the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness is weakened by the magnetic resistance of the permanent magnet 3 laminated thereon, and the product of the coercive force and the magnetization direction thickness is small. May be reduced.

  In the present embodiment, since the magnetic layer 5 is provided between the two types of permanent magnets 3 and 4, a magnetically parallel magnetic circuit is configured. That is, the magnetic flux from the permanent magnet 4 having a large product of the coercive force and the magnetization direction thickness only acts in a direction penetrating the permanent magnet 3 laminated thereon with a small product of the coercive force and the magnetization direction thickness. However, the magnetic layer 5 leaks to the side of the permanent magnet 3, and as a result, the magnetic flux penetrating the permanent magnet 3 and the magnetic flux leaking to the side act in parallel in the d-axis direction. By configuring the magnetic circuit in parallel as described above, the magnetic flux is distributed while avoiding the magnetoresistive portion, and the magnetic flux density of the magnet 4 having a large product of the coercive force and the magnetization direction thickness can be increased.

  As shown in FIG. 5B, when the magnetic layer 5 is provided between the two types of permanent magnets 3, 4, the outer peripheral permanent magnet 3 has a circumferential width wider than the inner peripheral permanent magnet 4. It can also be narrowed. If it does in this way, since a rotor iron core will contact the part of the difference of the width of permanent magnets 3 and 4, a part magnetic flux of the magnet of the inner circumference side will penetrate an air gap from this iron core part. .

(5. Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIG. In the present embodiment, the rotor core 2 is shaped such that the air gap length L1 near the d-axis, which is the central axis of the magnetic flux of the permanent magnet, is larger than the air gap length L2 near the q-axis between the magnetic poles.

  In the present embodiment, the magnetic field generated by the d-axis current is intended to act on the permanent magnets 3 and 4, but a leakage magnetic field is also generated. 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. Therefore, the magnetic field generated by the d-axis current for magnetizing the magnet can be effectively applied to the permanent magnets 3 and 4 disposed in the d-axis part. Further, a nonmagnetic portion that increases the magnetoresistance in the q-axis direction may be provided in the rotor core.

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

(1) Although the four-pole rotating electric machine is shown in each of the above embodiments, the present invention can naturally be applied to a multi-pole rotating electric machine such as eight-pole. 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.
Moreover, in the permanent magnet which forms a magnetic pole, the definition which distinguishes a permanent magnet with the product of a coercive force and the thickness of a magnetization direction is made. 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.

(2) As shown in FIG. 3, instead of arranging the permanent magnets 3 and 4 laminated in both the q-axis direction and the d-axis direction, the radially laminated permanent magnets 3 and 4 are arranged only in the q-axis direction. It is also possible. In that case, since the torque is reduced only by reducing the amount of magnets used, the permanent magnets 3 and 4 stacked in the q-axis direction are arranged instead of the q-axis direction permanent magnets 3 and 4 alone. It is conceivable to arrange magnets having a fixed magnetic force that are not stacked at substantially right angles. By doing so, the maximum magnetic force is increased. However, the variable range of the magnetic force is slightly reduced.

(3) During operation, the permanent magnet was 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 was changed irreversibly, and the phase was advanced with respect to the induced voltage of all 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.

Sectional drawing of the rotor of the 1st Embodiment of this invention. The schematic diagram which shows the effect | action of 1st Embodiment. Sectional drawing of the rotor of the 2nd Embodiment of this invention. Sectional drawing of the rotor of the 3rd Embodiment of this invention. Sectional drawing of the rotor of the 4th Embodiment of this invention. Sectional drawing of the rotor of the 5th Embodiment of this invention. Sectional drawing of the rotor of patent document 1. FIG. The schematic diagram which shows the effect | action of the rotor of patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Rotor core 3 ... Permanent magnet 4 in which product of coercive force and magnetization direction thickness becomes small Permanent magnet 5, 6 in which product of coercive force and magnetization direction thickness becomes large ... Cavity at end of permanent magnet 7 ... magnetic pole part 8 ... magnetic layer

Claims (18)

  Two or more types of permanent magnets with a product of coercive force and magnetization direction thickness different from other permanent magnets are arranged magnetically in series to form magnetic poles, and a plurality of these magnetic poles are arranged in the rotor core. A rotor is formed, and a stator is disposed on the outer periphery of the rotor via an air gap. An armature core and an armature winding are provided on the stator, and a magnetic field generated by the current of the armature winding A permanent magnet type rotating electrical machine characterized in that at least one of the permanent magnets constituting the magnetic pole of the rotor is magnetized to irreversibly change the amount of magnetic flux of the permanent magnet. In the permanent magnet type rotating electrical machine according to claim 1,
Two or more kinds of permanent magnets forming the magnetic pole are arranged in the rotor core so that the magnetic fluxes are added together, and the at least one permanent magnet is magnetized by the magnetic field generated by the current of the armature winding. The interlinkage magnetic flux by the permanent magnet is irreversibly decreased, and after the decrease, a magnetic field due to the current of the armature winding is generated in the direction opposite to the decrease, thereby magnetizing the at least one permanent magnet. A permanent magnet type rotating electrical machine characterized by irreversibly increasing the amount of flux linkage. In the permanent magnet type rotating electrical machine according to claim 2,
When reducing the interlinkage magnetic flux of a permanent magnet, the permanent magnet has a smaller product of coercive force and magnetization direction thickness than other permanent magnets. When the magnetic flux of the permanent magnet is irreversibly changed to increase the flux linkage of the permanent magnet, the permanent magnet having a small product of the coercive force and the magnetization direction thickness, A permanent magnet type rotating electrical machine characterized by irreversibly changing a magnetic field in the same direction. In the permanent magnet type rotating electrical machine according to any one of claims 1 to 3,
The permanent magnet is magnetized by a magnetic field generated by a d-axis current to change the amount of magnetic flux of the permanent magnet irreversibly, and a torque is controlled by a q-axis current at the same time as a d-axis current for magnetizing the permanent magnet flows. Magnet rotating electric machine. In the permanent magnet type rotating electrical machine according to any one of claims 1 to 4,
During operation, the permanent magnet is magnetized by a magnetic field generated by the d-axis current to irreversibly change the amount of magnetic flux of the permanent magnet, and the flux linkage of the armature winding generated by the current and the permanent magnet is generated by the magnetic flux generated by the d-axis current. Permanent magnet type rotating electrical machine characterized in that is reversibly changed.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 5, wherein the product of the coercive force and the thickness in the magnetization direction is larger than the others so that the magnetic flux of the permanent magnet of the magnetic pole is added at the maximum torque. A small permanent magnet is magnetized, and at a light load with a small torque and at a medium speed rotation range and a high speed rotation range, the permanent magnet whose product of the coercive force and the magnetization direction thickness is smaller than the other is magnetized by a magnetic field generated by an electric current. A permanent magnet type rotating electrical machine characterized by reducing magnetic flux. In the permanent magnet type rotating electrical machine according to any one of claims 1 to 6,
A permanent magnet type rotating electrical machine characterized in that a permanent magnet for irreversibly changing magnetic characteristics is arranged so that a biased magnetic field acts from another permanent magnet. The permanent magnet type rotating electrical machine according to any one of claims 1 to 7,
A permanent magnet type rotating electric machine, wherein two or more kinds of permanent magnets constituting a magnetic pole are arranged in a stacked manner. The permanent magnet type rotating electrical machine according to any one of claims 1 to 8,
A permanent magnet type rotating electrical machine characterized in that two or more types of permanent magnets constituting magnetic poles are arranged so that the magnetization direction is substantially in the d-axis direction.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 9, wherein two or more kinds of permanent magnets constituting the magnetic pole are arranged in a V shape or a U shape. Permanent magnet type rotating electric machine. The permanent magnet type rotating electrical machine according to any one of claims 1 to 10,
A permanent magnet type rotating electrical machine characterized in that two or more kinds of permanent magnets constituting a magnetic pole are arranged in the vicinity of the q-axis and the magnetization direction is substantially circumferential.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 11, wherein two or more kinds of permanent magnets constituting the magnetic pole are arranged with a magnetic pole portion interposed therebetween. Rotating electric machine.   The permanent magnet type rotating electrical machine according to any one of claims 1 to 12, wherein the magnetoresistance in the q-axis direction is made larger than the magnetoresistance in the d-axis direction excluding the magnet portion. Rotary electric machine. The permanent magnet type rotating electrical machine according to any one of claims 1 to 13,
An air gap length in the q-axis direction is made larger than an air gap length in the d-axis direction. The permanent magnet type rotating electrical machine according to any one of claims 1 to 14,
When the rotor reaches the maximum rotation speed with the magnetic flux linkage minimized by changing the magnetic pole magnet irreversibly, the induced electromotive force of the permanent magnet is less than the withstand voltage of the inverter electronic component that is the power supply for the rotating electrical machine. A permanent magnet type rotating electrical machine. The permanent magnet type rotating electrical machine according to any one of claims 1 to 15,
When a rotor is inserted into a stator and assembled, a permanent magnet having a small product of coercive force and magnetization direction thickness is irreversibly changed to reduce the interlinkage magnetic flux of the permanent magnet. Rotary electric machine. The permanent magnet type rotating electrical machine according to any one of claims 1 to 16,
A permanent magnet type rotating electric machine characterized by performing an operation of advancing a current phase in a state where a permanent magnet having a small product of coercive force and magnetization direction thickness is demagnetized until its polarity is reversed. The permanent magnet type rotating electrical machine according to any one of claims 1 to 17,
During operation, the permanent magnet is magnetized with a magnetic field generated by a pulsed d-axis current for a very short time to irreversibly change the amount of magnetic flux of the permanent magnet, and the current whose phase is advanced with respect to the induced voltage of all the magnets is continuous. The permanent magnet type rotating electrical machine is characterized by changing the amount of interlinkage magnetic flux of the armature winding generated by the current and the permanent magnet.

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