JP5178487B2 - Permanent magnet rotating electric machine - Google Patents

Description

  The present invention relates to a permanent magnet type rotating electrical machine having a conductive plate built into a rotor.

  In a permanent magnet type rotating electrical machine in which a permanent magnet is built in a rotor, 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 less than the withstand voltage.

  Therefore, a permanent magnet having a low coercive force (hereinafter referred to as a variable magnetic force magnet) in which the magnetic flux density is irreversibly changed by a magnetic field generated by the d-axis current of the stator winding, and a variable magnetic force magnet are included in the rotor. In a high-speed rotation range where a high coercivity permanent magnet (hereinafter referred to as a fixed magnet) having a coercive force more than double is placed and the maximum voltage of the power supply voltage is exceeded, the total flux linkage by the variable magnet and the fixed magnet is Techniques have been proposed for adjusting the total flux linkage so as to reduce. (See Patent Document 1 and Patent Document 2)

  Since the amount of magnetic flux of the permanent magnet is determined by the product of the coercive force and the magnetization direction thickness, when the variable magnetic magnet and the fixed magnetic magnet are actually incorporated in the rotor core, the permanent magnet is maintained as the variable magnetic magnet. A permanent magnet having a small product of magnetic force and magnetization direction thickness is used, and a permanent magnet having a large product of coercive force and magnetization direction thickness is used as the fixed magnet. In general, an alnico magnet, a samarium cobalt magnet (Samacoba magnet) or a ferrite magnet is used as the variable magnetic magnet, and a neodymium magnet (NdFeB magnet) is used as the fixed magnetic magnet.

JP 2006-280195 A JP 2008-48514 A

  By the way, in this type of permanent magnet type rotating electrical machine, when the variable magnetic magnet once demagnetized in the high speed rotation range is increased, the magnetic field of the fixed magnetic magnet arranged close to the variable magnetic magnet is increased by the d-axis current. There is a phenomenon in which the magnetic field for magnetism is hindered and the d-axis current (magnetization current) for magnetizing is increased accordingly.

  The present invention has been proposed in order to solve the problems of the prior art as described above, and its object is to arrange a conductive plate in the vicinity of a fixed magnetic magnet and to provide a d-axis current passing through the conductive plate. The present invention provides a permanent magnet type rotating electrical machine that suppresses an increase in d-axis current at the time of magnetizing by generating an induced current in a conductive plate by a magnetic field generated by and canceling out the magnetic field generated in the fixed magnetic magnet by the induced current. It is in.

In the present invention, apart from the rotor core, the magnetic path portion of other permanent magnets excluding the permanent magnet that irreversibly changes the conductive plate formed to have conductivity , or the magnetization of other permanent magnets It is provided so as to be adjacent to the periphery of the other permanent magnet with the direction as a central axis, and a magnetizing current is passed through the armature winding, and a short-circuit current is generated in the conductive plate by the magnetic flux. A magnetic field having a magnetic force in a direction opposite to a magnetic field generated by an electric current is generated. In particular, in the present invention, a block conductive plate which is a magnetic path portion where the magnetic flux leaks may be provided on the upper and lower sides, the periphery, the entire surface of the fixed magnetic force magnet.

  According to the present invention having the above-described configuration, an increase in d-axis current at the time of magnetization is suppressed by generating an induced current in the conductive plate and canceling out the magnetic field generated in the fixed magnetic force magnet by the induced current. As a result, an increase in the magnetization current at the time of demagnetization and increase of the magnetic pole of the rotor can be suppressed, so that the efficiency of the rotating machine can be achieved.

  Hereinafter, each embodiment of the permanent magnet type rotary electric 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 FIGS. FIG. 1 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of magnetic flux at the time of demagnetization, FIG. 2 is a view showing the direction of magnetic flux at the time of demagnetization, FIG. 3 is a perspective view of the portion of the fixed magnetic magnet 4 and the conductive plate 8 showing the direction of the magnetic flux at the time of magnetization.

  As shown in FIG. 1, the rotor 1 of the first embodiment of the present invention includes a rotor core 2, a permanent magnet 3 (hereinafter referred to as a variable magnetic force magnet) having a small product of coercive force and magnetization direction thickness, Permanent magnets (hereinafter referred to as fixed magnetic magnets) 4 and 4 having a large product of magnetic 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 magnets 4 and 4 are embedded in the rotor core 2. A cavity 5 serving as a magnetic barrier 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 in the thickness direction of the variable magnetic magnet 3 and the fixed magnetic magnet 4. .

  In this embodiment, the variable magnetic force magnet 3 is a ferrite magnet or an alnico magnet. In this embodiment, a ferrite magnet is used. The fixed magnetic magnet 4 was an NdFeB magnet. The coercive force of this variable magnetic magnet is 280 kA / m, and the coercive force of the fixed magnetic magnet is 1000 kA / m. The variable magnetic force magnet 3 is disposed in the rotor core 2 along the d-axis at the center of the magnetic pole, and the magnetization direction is substantially the circumferential direction. The fixed magnetic magnet 4 is disposed in the rotor core 2 on both sides of the variable magnetic magnet 3 so that the magnetization direction has a predetermined angle with respect to the d-axis direction.

  A thin plate-like conductive plate 8 is disposed so as to cover the entire upper and lower surfaces of the fixed magnetic magnet 4 embedded in the rotor core 2. This conductive plate 8 penetrates the magnetic flux generated when a d-axis current is passed through the armature winding together with the fixed magnetic magnet 4. At this time, the surface of the flat conductive plate 8 is spirally formed. A circulating short circuit current is generated. That is, it is preferable that the conductive plate 8 has a short-circuit current that can change the magnetization of the variable magnetic force magnet 3 within one second, and then attenuates the short-circuit current by 50% or more within one second. Further, when the inductance value and the resistance value of the conductive plate 8 are set to such values that a short-circuit current that changes the magnetization of the variable magnetic force magnet 3 flows, the efficiency is good.

  A stator 10 is provided on the outer periphery of the rotor 2 through an air gap 9. The stator 10 has an armature core 11 and an armature winding 12. An induced current is induced in the conductive plate 8 by the magnetizing current flowing through the armature winding 12, and a magnetic flux penetrating the conductive plate 8 is formed by the induced current.

  Further, the magnetization direction of the variable magnetic force magnet 3 reversibly changes due to the magnetization current flowing through the armature winding 12. That is, for the variable magnetic magnet and the fixed magnetic magnet, the permanent magnet 3 is magnetized by a magnetic field generated by the d-axis current during operation of the permanent magnet type rotating electric machine, and the amount of magnetic flux of the variable magnetic magnet 3 is irreversibly changed. . In this 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.

  In addition, the magnetic flux generated by the d-axis current causes the amount of interlinkage magnetic flux of the armature windings (of the rotating electric machine) The amount of interlinkage magnetic flux in the entire armature winding composed of the magnetic flux generated in the armature winding by the total current and the magnetic flux generated by the variable magnetic magnet and the fixed magnetic magnet on the rotor side is reversibly changed. .

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

(1-2. Basic action)
Next, the operation at the time of magnetizing and demagnetizing in the permanent magnet type rotating electric machine of the present embodiment having the above-described configuration will be described. In each figure, the direction of the magnetic force generated by the armature winding 12 and the conductive plate 8 is indicated by an arrow.

  In the present embodiment, a magnetic field is formed by applying a pulsed current having an energization time of about 0.1 ms to 100 ms to the armature winding 12 of the stator 10, and the magnetic field A is applied to the variable magnetic force magnet 3. Act (see FIG. 1). The pulse current that forms the magnetic field A for magnetizing the permanent magnet is the d-axis current component of the armature winding 12 of the stator 10. At this time, the magnetic field A1 acting other than the variable magnetic force magnet 3 is also generated by the pulse current.

  If the thicknesses of the two types of permanent magnets 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. A negative d-axis current that generates a magnetic field in the direction opposite to the magnetization direction of the permanent magnet is pulsed through the armature winding 12. If the magnetic field A in the magnet changed by the negative d-axis current becomes −280 kA / m, the coercive force of the variable magnetic magnet 3 is 280 kA / m, so that the magnetic force of the variable magnetic magnet 3 significantly decreases irreversibly.

  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. Further, when a reverse magnetic field greater than -280 kA / m is applied, the variable magnetic force magnet 3 is magnetized in the reverse direction and the polarity is reversed. In this case, since the magnetic flux of the variable magnetic magnet 3 and the magnetic flux of the fixed magnetic magnet 4 cancel each other, the total interlinkage magnetic flux of the permanent magnet is minimized.

  In this case, the direction of the magnetic force of the magnetic field generated by the fixed magnetic force magnet 4 is from the fixed magnetic force magnet 4 to the variable magnetic force magnet 3 as shown in FIG. Therefore, a strong magnetic force acts in the demagnetizing direction of the variable magnetic force magnet 3. At the same time, an induced current that cancels the magnetic field A of the armature winding 12 is generated on the conductive plate 8, and a magnetic field having a magnetic force direction as indicated by an arrow C in FIG. 1 is generated by the induced current. The magnetic force C generated by the conductive plate 8 also acts to direct the magnetization direction of the variable magnetic force magnet 3 in the reverse direction. Thus, demagnetization and polarity inversion of the variable magnetic force magnet 3 are efficiently performed. That is, the direction of the magnetic force of the magnetic field C generated by the induced current induced in the conductive plate 8 coincides with the direction of the magnetic field A by the magnetizing current in the portion that penetrates the variable magnetic force magnet 3, so that the magnetization in the demagnetizing direction Is also done effectively

  Next, a process of increasing the total interlinkage magnetic flux of the permanent magnet and restoring it to the maximum (magnetization process) will be described. In the demagnetization completed state, as shown in FIG. 2, the polarity of the variable magnetic force magnet 3 is reversed, and a positive magnetic field that generates a magnetic field in a direction opposite to the reversed magnetization (the initial magnetization direction shown in FIG. 1) is generated. A d-axis current is passed through the armature winding 12. The magnetic force of the reversed reversed polarity variable magnetic magnet 3 decreases as the magnetic field increases and becomes zero. When the magnetic field due to the positive d-axis current is further increased, the polarity is reversed and magnetized in the direction of the initial polarity. When 350 kA / m, which is a magnetic field necessary for almost complete magnetization, is applied, the variable magnetic force magnet 3 is magnetized and generates a magnetic force almost at its maximum.

  In this case, as in the case of demagnetization, it is not necessary to increase the d-axis current by continuous energization, and an instantaneous pulse current may be used as the current to achieve the target magnetic force. On the other hand, since the coercive force of the fixed magnetic magnet 4 is 1000 kA / m, the magnetic force of the fixed magnetic magnet 4 does not change irreversibly even when a magnetic field due to the d-axis current acts. 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. The variable magnetic force magnet 3 is magnetized by a magnetic field generated 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 conductive plate 8)
Next, the operation of the conductive plate 8 will be described. 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 acts not only on the variable magnetic magnet 3 but also on the fixed magnetic magnet 4. To do. 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 magnet 4 and concentrated on the variable magnetic magnet 3.

  In the present embodiment, the conductive plates 8 are arranged on the upper and lower surfaces of the fixed magnetic magnet 4 with the magnetization direction of the fixed magnetic magnet 4 as the central axis. Therefore, when the magnetization of the variable magnetic force magnet 3 shown in FIG. Flowing. Therefore, in the fixed magnetic force magnet 4, the magnetic field A1 due to the d-axis current and the magnetic field C due to the short-circuit current act and cancel each other, so that the magnetic field hardly increases or decreases. Therefore, the variable magnetic force magnet 3 can be magnetized with a small d-axis current. That is, the variable magnetic force magnet 3 can be effectively magnetized with a small magnetization current.

  At this time, the fixed magnetic magnet 4 is not affected by the d-axis current due to the conductive plate 8, and the magnetic flux hardly increases, so that the magnetic saturation of the armature core 11 due to the d-axis current can be reduced. That is, in the armature core 11, when the magnetic field A + the magnetic field A1 generated by the d-axis current passes through the magnetic path formed between the armature windings 12, there is a possibility that magnetic saturation of the portion occurs. However, in the present embodiment, the magnetic field C of the conductive plate 8 cancels the magnetic field A1, and the magnetic field A1≈0. Therefore, the component due to the magnetic field A1 in the magnetic flux passing through the magnetic path of the armature core 11 decreases. Magnetic saturation of the magnetic path of the armature core 11 is alleviated.

(2. Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of the magnetic flux at the time of demagnetization, and FIG. FIG. 6 is a perspective view of the portion of the fixed magnetic magnet 4 and the conductive plate 8 showing the direction of the magnetic flux at the time of magnetization.

  In the second embodiment, the conductive plate 8 is arranged in parallel to the upper and lower conductive plates 8 in the fixed magnetic magnet 4 in addition to the upper and lower surfaces of the fixed magnetic magnet 4. That is, each conductive plate 8 is provided so as to be orthogonal to the direction of the magnetic flux generated by the d-axis current (magnetization current).

  The second embodiment having such a configuration has the following characteristics in addition to the operational effects of the first embodiment. That is, when the variable magnetic force magnet 3 is magnetized in the demagnetizing direction shown in FIG. 4, the short-circuit current due to the magnetic field A ′ flowing upward from the side surface of the fixed magnetic force magnet 4 is also conducted in the fixed magnetic force magnet 4. It will flow to the plate 8. Even when the magnetization is reversed, as shown in FIG. 5, a short circuit current due to the magnetic field A ′ flowing from the upper side to the side surface of the fixed magnetic magnet 4 also flows in the internal conductive plate 8. As a result, the magnetic force of the magnetic field A ′ entering the fixed magnetic magnet 4 from the side can be attenuated by changing it to a short-circuit current, and this magnetic field A ′ increases the magnetic force of the fixed magnetic magnet 4 so that the variable magnetic force. It can suppress that the magnet 3 is prevented from being magnetized.

  Furthermore, in the first embodiment and the second embodiment, since the conductive plate 8 can be a plate-like member, it is possible to simplify the work of assembling the conductive plate 8 when manufacturing a permanent magnet type rotating electrical machine. It becomes. In particular, if the fixed magnetic magnet 4 and the conductive plate 8 are laminated and integrated, the conductive plate 8 can be assembled by the same operation as that for incorporating a normal permanent magnet into the iron core.

(3. Third embodiment)
A third embodiment of the present invention will be described with reference to FIGS. FIG. 7 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of the magnetic flux at the time of demagnetization, and FIG. FIG. 9 is a perspective view of the portion of the fixed magnetic magnet 4 and the conductive plate 8 showing the direction of the magnetic flux at the time of magnetization.

  In the third embodiment, the conductive plate 8 is a plate-like member that is in close contact with the side surface of the fixed magnetic force magnet 4 and is disposed so as to cover the fixed magnetic force magnet 4 in parallel with its magnetic path. That is, the conductive plate 8 is provided in parallel with the magnetization direction of the d-axis current with respect to the fixed magnetic force magnet 4 embedded in the rotor core 2.

  In the third embodiment in which the conductive plate 8 is wound around the fixed magnetic magnet 4 as described above, when the magnetic field A1 caused by the d-axis current acts on the fixed magnetic magnet 4, the magnetic field A1 is changed as shown in FIG. An induced current that cancels out flows through the conductive plate 8. At this time, the magnetic field C due to the short-circuit current acts uniformly in the fixed magnetic magnet 4. The same applies to FIG. 8, which is a case where the magnetization is reversed. Therefore, as an effect of the third embodiment, in addition to the effect of the above-described embodiment, the magnetic force of the magnetic field generated by the magnetizing current can be canceled over the entire area of the fixed magnetic magnet 4, so that the magnetic pole of the rotor can be increased. The increase in the magnetizing current at the time can be efficiently suppressed, and the efficiency of the rotating machine can be achieved. In addition, since the conductive plate 8 is disposed on the side surface of the fixed magnetic force magnet 4, there is an advantage that it is possible to prevent a magnetic field due to a magnetizing current from entering the fixed magnetic force magnet 4 from the side surface.

(4. Fourth embodiment)
A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 10 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of the magnetic flux at the time of demagnetization, and FIG. FIG. 12 is a perspective view of the portion of the fixed magnetic magnet 4 and the conductive plate 8 showing the direction of the magnetic flux at the time of magnetization.

  In the fourth embodiment, the conductive plate 8 is arranged on the upper and lower sides and the side surface of the fixed magnetic force magnet 4, that is, the entire periphery of the fixed magnetic force magnet 4, and the first and third embodiments are combined. . In this case, the conductive plate 8 may be a plate-shaped member joined to the surface of the fixed magnetic magnet 4 by welding or brazing, or the entire surface of the variable magnetic magnet 4 is covered with a conductive material by plating or other techniques. You may form by.

  In the fourth embodiment, in addition to the effects of the respective embodiments, the energy of the magnetic field A generated by the magnetizing current applied to the fixed magnetic magnet 4 from any direction is consumed as an induced current.

(5. Fifth embodiment)
A fifth embodiment of the present invention will be described with reference to FIGS. FIG. 13 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of the magnetic flux at the time of demagnetization, and FIG. 14 is also a view showing the direction of the magnetic flux at the time of demagnetization, FIG. 15 is a perspective view of the portions of the fixed magnetic magnet 4 and the conductive plate 8 showing the direction of the magnetic flux at the time of magnetization.

  In this fifth embodiment, the conductive plate 8 is an endless member through which the magnetic flux due to the d-axis current passes through the central opening, and is generated when the d-axis current is passed through the armature winding. A short-circuit current that circulates the endless conductive plate 8 is generated by the magnetic flux that is generated. The conductive plate 8 is provided in a magnetic path portion of the fixed magnetic magnet 4 excluding the variable magnetic magnet 3 and is arranged around the fixed magnetic magnet 4 with the magnetization direction of the fixed magnetic magnet 4 as a central axis.

  In this embodiment having such a configuration, when performing magnetization in the demagnetization direction of the variable magnetic force magnet 3 shown in FIG. 13, the short-circuit current due to the magnetic field A ′ flowing upward from the side surface of the fixed magnetic force magnet 4 is also fixed magnetic force. It flows to the conductive plate 8 disposed inside the magnet 4. Even when the magnetization is reversed, as shown in FIG. 6, a short-circuit current due to the magnetic field A ′ flowing from the upper side to the side surface of the fixed magnetic magnet 4 also flows through the conductive plate 8. Therefore, in addition to the effects of the above-described embodiments, the portion that covers the fixed magnetic magnet 4 with the conductive plate 8 is small, and the number of places where the conductive member serving as a magnetic barrier is disposed in the iron core is small. There is no risk of damaging the magnetic properties of the.

(6. Sixth embodiment)
A sixth embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a cross-sectional view in a direction orthogonal to the rotation axis of the permanent magnet type rotating electrical machine of the present embodiment, showing the direction of the magnetic flux at the time of demagnetization, and FIG. FIG. 18 is a perspective view of the bridge portion of the iron core showing the direction of the magnetic flux when magnetizing.

  In the sixth embodiment, the conductive plate 8 is a plate-like member that covers the periphery of the bridge portion 6 provided between the fixed magnetic magnet 4 and the variable magnetic magnet 3, and the conductive plate 8 is disposed inside the rotor core 2. The fixed magnetic magnet 4 embedded in is attached to the boundary of the magnetic path by the d-axis current of the fixed magnet.

  In the sixth embodiment having such a configuration, as shown in FIGS. 16 and 17, when the variable magnetic force magnet 3 is demagnetized or magnetized in the direction of magnetization, the magnetic field A <b> 2 due to the d-axis current is changed to the bridge portion 6. , An induced current that cancels the magnetic field A2 flows through the conductive plate 8. As a result, the magnetic field C generated by the induced current acts so as to cancel the magnetic field A2 caused by the d-axis current, so that a magnetic barrier can be created at the bridge portion 6. In particular, it is difficult to form a magnetic barrier by providing a cavity or the like in the bridge portion 6 due to demands on the strength of the iron core. However, according to the present embodiment, the magnetic strength of the bridge portion 6 is ensured while ensuring the mechanical strength. Since the barrier can be formed, as in the above-described embodiment, there is an effect that the magnetization can be effectively performed with a small magnetization current.

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

(1) 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. In particular, each of the above embodiments has a variable magnetic magnet arranged in the center and fixed magnetic magnets arranged on both sides thereof, but can be applied to other arrangements of variable magnetic magnets and fixed magnetic magnets.

(2) In the rotor core 2, in order to determine the shape and position of the cavity provided for forming 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.

(3) The above embodiments can be combined as appropriate. In particular, by providing the conductive plate 8 in both the bridge portion 6 and the fixed magnetic force magnet 4, the variable magnetic force magnet can be demagnetized or increased more effectively.

It is a fragmentary sectional view of the rotor and stator which show the 1st Embodiment of this invention, and shows the direction of the magnetic flux at the time of demagnetization. It is a fragmentary sectional view of the rotor and stator which show the 1st Embodiment of this invention, and shows the direction of the magnetic flux at the time of magnetization. It is a perspective view of the fixed magnetic force magnet 4 and the electrically-conductive board 8 part which show the direction of the magnetic flux at the time of the magnetization in the 1st Embodiment of this invention. It is a fragmentary sectional view of the rotor and stator which show the 2nd Embodiment of this invention, and shows the direction of the magnetic flux at the time of demagnetization. It is a fragmentary sectional view of the rotor and stator which show the 2nd Embodiment of this invention, and shows the direction of the magnetic flux at the time of magnetizing. It is a perspective view of the fixed magnetic magnet 4 and the electrically-conductive board 8 part which shows the direction of the magnetic flux at the time of the magnetization in the 2nd Embodiment of this invention. It is a fragmentary sectional view of the rotor and stator which show the 3rd Embodiment of this invention, and shows the direction of the magnetic flux at the time of a demagnetization. It is a fragmentary sectional view of the rotor and stator which shows the 3rd Embodiment of this invention, and shows the direction of the magnetic flux at the time of magnetization. It is a perspective view of the fixed magnetic force magnet 4 and the electrically-conductive board 8 part which show the direction of the magnetic flux at the time of the magnetization in the 3rd Embodiment of this invention. It is a fragmentary sectional view of the rotor and stator which shows the 4th Embodiment of this invention, and shows the direction of the magnetic flux at the time of a demagnetization. It is a fragmentary sectional view of the rotor which shows the 4th Embodiment of this invention, and a stator, and shows the direction of the magnetic flux at the time of magnetization. It is a perspective view of the fixed magnetic force magnet 4 and the electrically-conductive board 8 part which show the direction of the magnetic flux at the time of the magnetization in the 4th Embodiment of this invention. It is a fragmentary sectional view of the rotor and stator which show the 5th Embodiment of this invention, and shows the direction of the magnetic flux at the time of demagnetization. It is a fragmentary sectional view of the rotor and stator which shows the 5th Embodiment of this invention, and shows the direction of the magnetic flux at the time of a magnetization. It is a perspective view of the fixed magnetic force magnet 4 and the electrically-conductive board 8 part which show the direction of the magnetic flux at the time of the magnetization in the 5th Embodiment of this invention. It is a fragmentary sectional view of the rotor and stator which show the 6th Embodiment of this invention, and shows the direction of the magnetic flux at the time of demagnetization. It is a fragmentary sectional view of the rotor and stator which show the 6th Embodiment of this invention, and shows the direction of the magnetic flux at the time of a magnetizing. It is a perspective view of the bridge | bridging part 6 and the electrically-conductive board 8 part which shows the direction of the magnetic flux at the time of the magnetization in the 6th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rotor 2 ... Rotor core 3 ... Permanent magnet with small product of coercive force and magnetization direction thickness (variable magnetic force magnet)
4. Permanent magnet with a large product of coercive force and magnetization direction thickness (fixed magnet)
5 ... Cavity 6 at the end of the permanent magnet 6 ... Bridge portion 8 ... Conductive plate 9 ... Air gap 10 ... Stator 11 ... Armature core 12 ... Armature winding

Claims (8)

A magnetic pole is formed by using two or more types of permanent magnets whose product of coercive force and magnetization direction thickness is different from other permanent magnets, and a plurality of the magnetic poles are arranged in the rotor core to constitute a rotor. A stator is arranged on the outer periphery of the child via an air gap, an armature core and an armature winding are provided on the stator, and a magnetic pole generated by the current of the armature winding constitutes the magnetic pole of the rotor. In a permanent magnet type rotating electrical machine that magnetizes at least one of the magnets and irreversibly changes the amount of magnetic flux of the permanent magnet,
Aside from the rotor core, a conductive plate formed to have conductivity is adjacent to the other permanent magnet in a magnetic path portion of another permanent magnet excluding the permanent magnet that irreversibly changes the conductive plate. Provided,
By passing a magnetizing current through the armature winding, a short-circuit current is generated in the conductive plate by the magnetic flux,
A permanent magnet type rotating electrical machine that generates a magnetic field having a magnetic force in a direction opposite to a magnetic field generated by a magnetizing current by the short-circuit current. A magnetic pole is formed by using two or more types of permanent magnets whose product of coercive force and magnetization direction thickness is different from other permanent magnets, and a plurality of the magnetic poles are arranged in the rotor core to constitute a rotor. A stator is arranged on the outer periphery of the child via an air gap, an armature core and an armature winding are provided on the stator, and a magnetic pole generated by the current of the armature winding constitutes the magnetic pole of the rotor. In a permanent magnet type rotating electrical machine that magnetizes at least one of the magnets and irreversibly changes the amount of magnetic flux of the permanent magnet,
Separately from the rotor core , around the other permanent magnet with the magnetization direction of another permanent magnet as a central axis except for the permanent magnet that irreversibly changes a conductive plate formed to have conductivity , Provided adjacent to the other permanent magnet ,
By passing a magnetizing current through the armature winding, a short-circuit current is generated in the conductive plate by the magnetic flux,
A permanent magnet type rotating electrical machine that generates a magnetic field having a magnetic force in a direction opposite to a magnetic field generated by a magnetizing current by the short-circuit current.   2. The permanent magnet type rotating electrical machine according to claim 1, wherein the conductive plates are provided on both upper and lower surfaces opposite to a magnetization direction of another permanent magnet excluding a permanent magnet that is irreversibly changed. The permanent magnet type rotating electrical machine according to claim 3 , wherein another conductive plate is provided inside the other permanent magnet in parallel with the conductive plates provided on both upper and lower surfaces.   The permanent magnet type rotating electric machine according to claim 1 or 2, wherein the entire periphery of the other permanent magnet is covered with a conductive plate.   The permanent magnet type rotating electrical machine according to claim 1, wherein a conductive plate having an open center is disposed around at least one of upper and lower surfaces of the other permanent magnet. The permanent magnet type rotating electric machine according to any one of claims 3 to 6 , wherein the conductive plate is provided in a bridge portion provided between the adjacent variable magnetic magnet and fixed magnetic magnet. The permanent magnet type rotation according to any one of claims 1 to 7 , wherein a variable magnetic force magnet is disposed at a central portion in each magnetic pole of the rotor core, and a fixed magnetic force magnet is disposed on both sides thereof. Electric.

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