Motor control method
阅读说明:本技术 电动机的控制方法 (Motor control method ) 是由 佐久间纪次 矢野正雄 伊东正朗 庄司哲也 岸本秀史 加藤晃 于 2019-07-17 设计创作,主要内容包括:本发明提供一种电动机的控制方法,在可变磁场电动机中,能够不用产生与永磁体的磁通量反方向的磁通量就使高旋转时的拖曳损失降低。永磁体是具备磁性相和存在于所述磁性相的周围的晶界相的复合永磁体,所述磁性相具备芯部和存在于所述芯部的周围的外廓部,所述芯部以及所述外廓部中的一方的居里温度为T<Sub>c1</Sub>K,另一方的居里温度为T<Sub>c2</Sub>K,且所述T<Sub>c2</Sub>K高于所述T<Sub>c1</Sub>K,并且所述电动机的控制方法包括:在磁阻转矩的大小为永磁转矩的大小以上时,使所述复合永磁体的温度为(T<Sub>c1</Sub>-100)K以上且小于T<Sub>c2</Sub>K的T<Sub>s</Sub>K;以及在磁阻转矩的大小小于永磁转矩的大小时,使所述复合永磁体的温度小于T<Sub>S</Sub>K以及T<Sub>c1</Sub>K中的任意较低一方的温度。(The invention provides a control method of a motor, which can reduce drag loss during high rotation without generating magnetic flux in the opposite direction of the magnetic flux of a permanent magnet in a variable magnetic field motor. The permanent magnet is a composite permanent magnet including a magnetic phase and a grain boundary phase present around the magnetic phase, the magnetic phase includes a core portion and an outer shell portion present around the core portion, and one of the core portion and the outer shell portion has a Curie temperature T c1 K, the Curie temperature of the other is T c2 K, and said T c2 K is higher than T c1 K, and the control method of the motor includes: when the reluctance torque is larger than the permanent magnet torque, the composite permanent magnet is drivenThe temperature of the magnet is (T) c1 -100) K is more than and less than T c2 T of K s K; and when the reluctance torque is smaller than the permanent magnet torque, enabling the temperature of the composite permanent magnet to be smaller than T S K and T c1 The lower temperature of K.)
1. A control method of an electric motor which arranges permanent magnets in a rotor and utilizes permanent magnet torque and reluctance torque, wherein,
the permanent magnet is a composite permanent magnet including a magnetic phase and a grain boundary phase present around the magnetic phase, the magnetic phase includes a core portion and an outer shell portion present around the core portion, and one of the core portion and the outer shell portion has a Curie temperature T c1K, the Curie temperature of the other is T c2K, and said T c2K is higher than T c1K,
Further, the method for controlling the motor includes:
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K is more than and less than T c2T of K sK; and
when the magnitude of the reluctance torque is smaller than that of the permanent magnet torque, the temperature of the composite permanent magnet is made to be smaller than T SK and T c1The lower temperature of K.
2. The control method of an electric motor according to claim 1,
the core has a Curie temperature of T c1K, and the Curie temperature of the profile is T c2K。
3. The control method of an electric motor according to claim 2,
the composite permanent magnet has (R) 2 (1-x)R 1 x) yFe (100-y-w-z-v)Co wB zM vIn which R is 2Is more than 1 selected from the group consisting of Nd and Pr 11 or more selected from the group consisting of Ce, La, Gd, Y and Sc, M is 1 or more selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In and Mn and unavoidable impurities, 0 < x <1, Y is 12 to 20, z is 5.6 to 6.5, w is 0 to 8 and v is 0 to 2,
r in the core 1/(R 2+R 1) Greater than R in the outer contour 1/(R 2+R 1)。
4. The control method of an electric motor according to claim 3,
the average particle diameter of the magnetic phase is 1000nm or less.
5. The control method of an electric motor according to claim 3 or 4,
the R is 1Is more than 1 selected from the group consisting of Ce and La, and the R 2Is Nd.
6. The control method of an electric motor according to claim 3 or 4,
the R is 1Is Ce, and said R 2Is Nd.
7. The control method of an electric motor according to claim 1,
the core has a Curie temperature of T c2K, and the Curie temperature of the profile is T c1K。
8. The control method of an electric motor according to claim 7,
the composite permanent magnet has (R) 2 (1-x)R 1 x) yFe (100-y-w-z-v)Co wB zM vIn which R is 2Is more than 1 selected from the group consisting of Nd and Pr 11 or more selected from the group consisting of Ce, La, Gd, Y and Sc, M is 1 or more selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In and Mn and unavoidable impurities, 0 < x <1, Y is 12 to 20, z is 5.6 to 6.5, w is 0 to 8 and v is 0 to 2,
r in the core 2/(R 2+R 1) Greater than R in the outer contour 2/(R 2+R 1)。
9. The control method of an electric motor according to claim 8,
the average particle diameter of the magnetic phase is 1000nm or less.
10. The control method of an electric motor according to claim 8 or 9,
the R is 1Is more than 1 selected from the group consisting of Ce and La, and the R 2Is Nd.
11. The control method of a square motor according to claim 8 or 9,
the R is 1Is Ce, and said R 2Is Nd.
12. The control method of the motor according to any one of claims 1 to 11, wherein the method includes:
when the reluctance torque is greater than or equal to the permanent magnet torque, a heat insulating material is disposed in the motor so that the temperature of the composite permanent magnet is (T) c1-100) K is more than and less than T c2T of K sK; and
when the reluctance torque is smaller than the permanent magnet torque, removing the heat insulating material from the motor to make the temperature of the composite permanent magnet less than T SK and T c1The lower temperature of K.
13. The control method of an electric motor according to any one of claims 1 to 11,
the method comprises the following steps:
when the reluctance torque is greater than or equal to the permanent magnet torque, the heat radiating member of the motor is removed to set the temperature of the composite permanent magnet to (T) c1-100) K is more than and less than T c2T of K sK; and
when the reluctance torque is smaller than the permanent magnet torque, the heat dissipation component is configured on the motor again, so that the temperature of the composite permanent magnet is less than T SK and T c1The lower temperature of K.
14. The control method of an electric motor according to any one of claims 1 to 11,
the method comprises the following steps:
configuring the electric motor to an electric vehicle;
when the reluctance torque is greater than or equal to the permanent magnet torque, the flow rate of the cooling fluid supplied to the motor is reduced to set the temperature of the composite permanent magnet to (T) c1-100) K is more than and less than T c2T of K sK; and
when the magnitude of reluctance torque is smaller than that of permanent magnet rotorWhen the moment is large, the flow of the cooling fluid is increased, so that the temperature of the composite permanent magnet is less than T SK and T c1The lower temperature of K.
15. The control method of an electric motor according to claim 14,
the electric vehicle is a hybrid vehicle provided with an engine and the motor,
the cooling fluid is a lubricating fluid filled in a power split device that connects the engine and the electric motor.
16. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-50) K is more than and less than T c2T of K sK。
17. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than and less than T c2T of K sK。
18. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K or more and (T) c2-5) T below K sK。
19. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-50) K is more than or equal to (T) c2-5) T below K sK。
20. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than or equal to (T) c2-5) T below K sK。
21. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K or more and (T) c1+50) K or less T sK。
22. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-50) K or more and (T) c1+50) K or less T sK。
23. The control method of an electric motor according to any one of claims 1 to 15,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than or equal to (T) c1+50) K or less T sK。
24. The control method of an electric motor according to any one of claims 1 to 23,
the temperature of the composite permanent magnet is detected by a temperature sensor disposed inside or outside the motor.
Technical Field
The present disclosure relates to a control method of a motor. The present disclosure particularly relates to a control method of a motor that configures permanent magnets in a rotor and utilizes permanent magnet torque and reluctance torque.
Background
Conventionally, the performance of a motor is evaluated by efficiency in rated operation (operation in which the rotation speed and the torque are constant). However, the performance of a motor used in a mobile body such as an automobile is difficult to evaluate with efficiency at the time of rated operation. For example, in a driving motor of an automobile or the like, the motor is used at a high torque at a low rotation time (at the time of starting the vehicle) and at a low torque at a high rotation time (at the time of normal running). Therefore, in a driving motor for an automobile or the like, high efficiency is required in a wide rotation range from low rotation to high rotation.
As a driving motor for automobiles and the like, a Permanent Magnet motor (PM motor) is used. A permanent magnet motor is a motor in which a permanent magnet is disposed in a rotor (rotor), and is also called a magnet synchronous motor.
When a permanent magnet having a high magnetic flux is used as the permanent magnet disposed in the rotor of the permanent magnet motor, a high torque can be obtained. Since a high torque is required at the time of starting a vehicle as a driving motor for an automobile or the like, a permanent magnet having a high magnetic flux is applied as a permanent magnet disposed on a rotor. On the other hand, a high torque is not required during normal running, as in starting. During normal running, the motor is operated at a higher rotation speed than at the time of starting.
In a permanent magnet motor, the back electromotive force increases as the rotation speed increases. The larger the magnetic flux of the permanent magnet disposed in the rotor, the larger the back electromotive force. Further, the back electromotive force causes drag loss. Accordingly, when a permanent magnet motor in which permanent magnets having high magnetic fluxes are arranged in a rotor is used as a driving motor of an automobile, high torque is obtained at the time of starting, but drag loss becomes large at the time of normal running (at the time of high rotation).
In order to reduce drag loss, a variable field motor has been proposed in which the magnetic flux of a permanent magnet disposed in a rotor is reduced at the time of high rotation. For example,
Prior art documents
Patent document
Patent document 1: japanese patent laid-open publication No. 2016-103936
Disclosure of Invention
Problems to be solved by the invention
In the motor disclosed in
The present inventors have found the following problems: since the back electromotive force at the time of high rotation is a high voltage, the load on the inverter connected to the stator coil is large in order to generate a magnetic flux for canceling the back electromotive force by the stator coil.
The present disclosure has been made to solve the above problems. An object of the present disclosure is to provide a method for controlling a motor, which can reduce drag loss at the time of high rotation without generating a magnetic flux in the opposite direction to that of a permanent magnet disposed on a rotor in a variable field motor.
Means for solving the problems
The present inventors have conducted extensive studies to achieve the above object, and have completed a method for controlling a motor according to the present disclosure. The control method of the motor of the present disclosure includes the following aspects.
<1> a control method of a motor which configures permanent magnets in a rotor and uses permanent magnet torque and reluctance torque, wherein,
the permanent magnet is a composite permanent magnet including a magnetic phase and a grain boundary phase present around the magnetic phase, the magnetic phase includes a core portion and an outer shell portion present around the core portion, and one of the core portion and the outer shell portion has a Curie temperature T c1K, the Curie temperature of the other is T c2K, and said T c2K is higher than T c1K,
Further, the method for controlling the motor includes:
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K is more than and less than T c2T of K sK; and
when the magnitude of the reluctance torque is smaller than that of the permanent magnet torque, the temperature of the composite permanent magnet is made to be smaller than T SK and T c1The lower temperature of K.
<2> the method according to the <1>, wherein,
the core has a Curie temperature of T c1K, and the Curie temperature of the profile is T c2K。
<3> the method according to the <2>, wherein,
the composite permanent magnet has (R) 2 (1-x)R 1 x) yFe (100-y-w-z-v)Co wB zM vIn which R is 2Is more than 1 selected from the group consisting of Nd and Pr 1Is at least 1 selected from the group consisting of Ce, La, Gd, Y and Sc, and M is at least 1 selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In and Mn, and is unavoidableX is more than 0 and less than 1, y is 12 to 20, z is 5.6 to 6.5, w is 0 to 8, and v is 0 to 2,
r in the core 1/(R 2+R 1) Greater than R in the outer contour 1/(R 2+R 1)。
<4> the method according to the <3>, wherein,
the average particle diameter of the magnetic phase is 1000nm or less.
<5> the method according to the item <3> or <4>, wherein,
the R is 1Is more than 1 selected from the group consisting of Ce and La, and the R 2Is Nd.
<6> the method according to the item <3> or <4>, wherein,
the R is 1Is Ce, and said R 2Is Nd.
<7> the method according to the <1> item, wherein,
the core has a Curie temperature of T c2K, and the Curie temperature of the profile is T c1K。
<8> the method according to the <7>, wherein,
the composite permanent magnet has (R)
2 (1-x)R
1 x)
yFe
(100-y-w-z-v)Co
wB
zM
vIn which R is
2Is more than 1 selected from the group consisting of Nd and
r in the core 2/(R 2+R 1) Greater than R in the outer contour 2/(R 2+R 1)。
<9> the method according to the item <8>, wherein,
the average particle diameter of the magnetic phase is 1000nm or less.
<10> the method according to the item <8> or <9>, wherein,
the R is 1Is more than 1 selected from the group consisting of Ce and La, and the R 2Is Nd.
<11> the method according to the item <8> or <9>, wherein,
the R is 1Is Ce, and said R 2Is Nd.
<12> the method according to any one of <1> to <11>, wherein,
the method comprises the following steps:
when the reluctance torque is greater than or equal to the permanent magnet torque, a heat insulating material is disposed in the motor so that the temperature of the composite permanent magnet is (T) c1-100) K is more than and less than T c2T of K sK; and
when the reluctance torque is smaller than the permanent magnet torque, removing the heat insulating material from the motor to make the temperature of the composite permanent magnet less than T SK and T c1The lower temperature of K.
<13> the method according to any one of <1> to <11>, wherein,
the method comprises the following steps:
when the reluctance torque is greater than or equal to the permanent magnet torque, the heat radiating member of the motor is removed to set the temperature of the composite permanent magnet to (T) c1-100) K is more than and less than T c2T of K sK; and
when the reluctance torque is smaller than the permanent magnet torque, the heat dissipation component is configured on the motor again, so that the temperature of the composite permanent magnet is less than T SK and T c1The lower temperature of K.
<14> the method according to any one of <1> to <11>, wherein,
the method comprises the following steps:
configuring the electric motor to an electric vehicle;
when the reluctance torque is greater than or equal to the permanent magnet torque, the flow rate of the cooling fluid supplied to the motor is reduced to set the temperature of the composite permanent magnet to (T) c1-100) K is more than and less than T c2T of K sK; and
when the magnitude of the reluctance torque is smaller than that of the permanent magnet torque, the flow rate of the cooling fluid is increased, so that the temperature of the composite permanent magnet is smaller than T SK and T c1The lower temperature of K.
<15> the method according to the item <14>, wherein,
the electric vehicle is a hybrid vehicle provided with an engine and the motor,
the cooling fluid is a lubricating fluid filled in a power split device that connects the engine and the electric motor.
<16> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-50) K is more than and less than T c2T of K sK。
<17> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than and less than T c2T of K sK。
<18> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K or more and (T) c2-5) T below K sK。
<19> the method according to any one of <1> to <15>, wherein,
in the magnetic resistanceWhen the torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is (T) c1-50) K or more and (T) c2-5) T below K sK。
<20> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than or equal to (T) c2-5) T below K sK。
<21> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-100) K or more and (T) c1+50) K or less T sK。
<22> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is larger than the permanent magnet torque, the temperature of the composite permanent magnet is set to be (T) c1-50) K or more and (T) c1+50) K or less T sK。
<23> the method according to any one of <1> to <15>, wherein,
when the reluctance torque is more than the permanent magnet torque, the temperature of the composite permanent magnet is T c1K is more than or equal to (T) c1+50) K or less T sK。
<24> the method according to any one of <1> to <23>, wherein,
the temperature of the composite permanent magnet is detected by a temperature sensor provided inside or outside the motor.
Effects of the invention
According to the present disclosure, a composite permanent magnet having at least two different curie temperatures is applied to a rotor of a permanent magnet motor, and the temperature of the composite permanent magnet is controlled according to the rotational speed of the motor, thereby enabling the composite permanent magnet to be self-demagnetized (self-demagnetization) and self-remagnetized (self-remagnetization). As a result, according to the present disclosure, it is possible to provide a method of controlling an electric motor capable of reducing drag loss at the time of high rotation without generating a magnetic flux in the opposite direction to the magnetic flux of the permanent magnet disposed on the rotor.
Drawings
Fig. 1 is a schematic view showing an example of arranging a composite permanent magnet in a rotor of an embedded magnet type motor.
Fig. 2 is a schematic view showing an alloy structure of the composite permanent magnet.
Fig. 3 is a schematic diagram showing an example of a drive mechanism of the hybrid vehicle.
Fig. 4 is a view showing the results of EPMA surface analysis of the alloy structure observed with a Scanning Transmission Electron Microscope (STEM) for the permanent magnet of the example.
Fig. 5 is a graph showing the results of measuring curie temperatures for the permanent magnets of the examples and comparative examples.
Fig. 6 is a graph showing the relationship between the application temperature and the magnetic recovery rate of the composite permanent magnet according to the example.
Detailed Description
Hereinafter, an embodiment of the motor control method of the present disclosure will be described in detail. The embodiments described below do not limit the method of controlling the motor according to the present disclosure.
A Permanent Magnet motor (PM motor) is a motor in which Permanent magnets are arranged in a rotor (rotor) and Permanent Magnet torque and reluctance torque are used. The permanent magnet torque is a torque generated by interaction between a magnetic flux generated by a permanent magnet disposed in a rotor and a magnetic flux generated by a stator coil (stator coil). The reluctance torque is a torque generated by interaction of a core portion of the surface of the rotor and magnetic flux generated by the stator coil.
In the permanent magnet motor, a high torque is obtained at low rotation, but as the rotation speed increases, the back electromotive force increases, and the drag loss increases. In addition, in the permanent magnet motor, the permanent magnet torque is larger than the reluctance torque at the time of low rotation, and the reluctance torque increases as the rotation speed increases.
When a permanent magnet motor is used as a driving motor of an automobile, the reluctance torque is larger than the permanent magnet torque during normal running and highway running. During such high rotation (hereinafter, sometimes simply referred to as "high rotation"), the permanent magnet motor has a large drag loss due to an increase in back electromotive force.
In order to reduce (demagnetize) the magnetic flux of the permanent magnet at the time of high rotation, conventionally, a magnetic flux in the opposite direction to the magnetic flux of the permanent magnet is applied from the outside of the permanent magnet. When the motor is returned from high rotation to low rotation in the operating state, the magnetic flux in the same direction as the permanent magnet acts from the outside of the permanent magnet in order to re-magnetize the permanent magnet that is temporarily demagnetized.
Instead of this, the present inventors have recognized that the composite permanent magnet having at least two different curie temperatures is disposed in the rotor, and the temperature of the composite permanent magnet is controlled according to the rotation speed of the motor, thereby enabling the composite permanent magnet to be self-demagnetized and self-remagnetized. Further, the present inventors have recognized that such a composite permanent magnet is obtained not by joining permanent magnets having different curie temperatures but by forming an alloy structure (magnetic phase structure) having different curie temperatures in one permanent magnet.
Next, the constituent elements of the motor control method of the present disclosure based on these findings will be described.
Method for controlling motor
A motor to which a method for controlling a motor according to the present disclosure (hereinafter, sometimes referred to as a "method of the present disclosure") is applied is a motor in which a permanent magnet is disposed in a rotor and permanent magnet torque and reluctance torque are used. The permanent magnet may be a composite permanent magnet as described later. Such motors are generally referred to as Permanent Magnet motors (PM motors).
Examples of the permanent magnet motor include a surface magnet motor and an embedded magnet motor. The Surface magnet type motor is a motor in which a permanent magnet is attached to a Surface of a rotor, and is also called an SPM (Surface permanent magnet motor). The embedded Magnet type motor is a motor in which a Permanent Magnet is mounted inside a core of a rotor, and is also called IPM (Interior Permanent Magnet).
As permanent magnets arranged on the rotor, use is made of a permanent magnet with at least two different Curie temperatures T c1K and T c2K and T c2K is higher than T c1K.
The position of the composite permanent magnet in the rotor may be the same as that of a conventional permanent magnet motor. Fig. 1 is a schematic view showing an example of arranging a composite permanent magnet in a rotor of an embedded magnet type motor. In the example shown in fig. 1, the
In the example shown in fig. 1, one composite
In the method of the present disclosure, the permanent magnets arranged in the
The composite
Fig. 2 is a schematic view showing a part of the alloy structure of the composite
The magnetic force of the composite
Since the
The Curie temperature of the
< demagnetization Process >
In the method of the present disclosure, when the magnitude of the reluctance torque is equal to or greater than the magnitude of the permanent magnet torque, the temperature of the composite
To make composite permanentThe temperature of the
Since the composite
Alternatively, the relationship between the temperature of the immovable portion, which is a portion other than the movable portion such as the
As described above, the
The magnetic phase gradually demagnetizes itself with an increase in temperature, and completely loses its magnetic properties when the curie temperature is reached. In the
On the other hand, if the temperature of the composite
At a Curie temperature of T
c1When K is partially re-magnetized, the Curie temperature is T
c2The higher the magnetic flux of the part of K, the better. To make Curie temperature T
c1K is partially demagnetized so that the temperature of the composite
For example, the Curie temperature at the
Contrary to the above-described solution, the Curie temperature at the
< Process of remagnetization >
In the method of the present disclosure, when the magnitude of the reluctance torque is smaller than that of the permanent magnet torque (when the motor is in low rotation), the temperature of the composite
In this specification, "re-magnetization" includes not only a case where a portion completely losing magnetism is re-magnetized but also a case where a portion where the magnetic flux is reduced (a demagnetized portion) is increased (restored) in magnetic flux. The "case where the magnetic flux of the portion where the magnetic flux is reduced (portion where demagnetization is performed) is increased (restored)" may be, for example, as follows. In reluctance torqueWhen the magnitude of (d) is equal to or greater than the magnitude of the permanent magnet torque (during high rotation), the temperature of the composite
The definition of "re-magnetization" is explained not to set the temperature of the composite
When the magnitude of the reluctance torque is smaller than the magnitude of the permanent magnet torque (at the time of low rotation), the temperature of the composite
On the other hand, when the magnitude of the reluctance torque is smaller than the magnitude of the permanent magnet torque (at the time of low rotation), the temperature of the composite
In the following description, "the temperature of the composite
In order to make the temperature of the composite
Since the composite
Alternatively, the relationship between the temperature of the immovable portion, which is a portion other than the movable portion such as the
From the viewpoint of ensuring the re-magnetization, when the magnitude of the reluctance torque is smaller than the magnitude of the permanent magnet torque (when the motor is in low rotation), the temperature of the composite
By re-magnetizing the composite
For example, the Curie temperature at the
Contrary to the above-described solution, the Curie temperature at the
As described so far, in the method of the present disclosure, the temperature of the composite
< removal of Heat insulating Material >
In order to make the temperature of the composite
When the motor is operated at high rotation, the electric motor generates heat by itself due to the rise of the counter electromotive force. The temperature of the composite
However, the temperature at the composite
The kind of the heat insulating material and the like are not particularly limited. Examples of the kind of the heat insulating material include fiber materials such as glass wool and foam materials such as rigid polyurethane.
< removal and attachment of Heat radiating Member >
A heat radiating member such as a cooling fin is often mounted on the motor. The temperature of the composite
Specifically, when the magnitude of the reluctance torque is equal to or greater than the magnitude of the permanent magnet torque, the temperature of the composite permanent magnet can be set to (T) by removing the heat radiating member of the motor c1-100) K is more than and less than T c2T of K sK. On the other hand, when the magnitude of the reluctance torque is smaller than the magnitude of the permanent magnet torque, the heat radiating member may be disposed again in the motor so that the temperature of the composite permanent magnet may be made smaller than T SK and T c1The lower temperature of K.
The material of the heat dissipation member and the like are not particularly limited. Examples of the material of the heat dissipating member include a ceramic material such as AlN (aluminum nitride), a metal material such as aluminum or an aluminum alloy, and an organic material in which AlN or BN (boron nitride) filler is dispersed.
< utilization of Cooling fluid >
An electric vehicle is often provided with a cooling device for an inverter. And, the cooling fluid circulates in the cooling device. This cooling fluid may be utilized in order to vary the composite
The temperature of the composite
When the magnitude of the reluctance torque is equal to or greater than the magnitude of the permanent magnet torque, the flow rate of the cooling fluid is reduced, the cooling of the composite
The cooling fluid is introduced into the electric motor from a cooling device disposed in the electric vehicle by using a pump or the like. The cooling device may be used for cooling the inverter or may be dedicated for cooling the motor. The cooling fluid is not particularly limited as long as it can cool the motor, and is typically water. The water may also contain an antifreeze.
In the case where the electric vehicle is a hybrid vehicle including an engine and a motor, a lubricating fluid filled in a power split device that connects the engine and the motor may be used as the cooling fluid. That is, when the electric motor is disposed in the hybrid vehicle, the lubricating fluid of the power split device may be used to change the temperature of the composite
Fig. 3 is a schematic diagram showing an example of a drive mechanism of the hybrid vehicle. In the embodiment shown in fig. 3, the
The lubricating fluid is relatively cold (from ambient temperature to about 50 ℃). Therefore, as shown in fig. 3, the lubricating
Further, since the amount of the lubricating fluid is sufficiently used as the cooling medium, the composite
For example, when the magnitude of the reluctance torque is equal to or greater than the magnitude of the permanent magnet torque, the flow rate of the lubricating fluid is reduced, the cooling of the composite
< temperature measurement of composite permanent magnet >
The temperature of the composite
Since the composite
< composite permanent magnet >
The composite
In the present specification, as the configuration of the composite
< rare-earth magnet A (embodiment 1) >
The rare earth magnet A has a magnet composition consisting of
2 (1-x)R
1 x)
yFe
(100-y-w-z-v)Co
wB
zM
vThe overall composition of the representation. The overall composition is the total composition of the
In the above composition formula, R 2Is at least 1 selected from the group consisting of Nd and Pr. R 1Is at least 1 selected from the group consisting of Ce, La, Gd, Y and Sc. M is at least 1 selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In and Mn, and unavoidable impurities.
The rare earth magnet A is obtained by adding R as a modifying material
2Diffusion infiltration of a low melting point alloy having a composition consisting of R
1 2(Fe、Co)
14B or (R)
2、R
1)
2(Fe、Co)
14B, a magnetic phase, and a rare earth magnet precursor. At this time, R in the magnetic phase of the rare-earth magnet precursor
1And R in the modifying material
2And (6) replacing. This replacement occurs only in the vicinity of the surface of the magnetic phase of the rare-earth magnet precursor. Therefore, as shown in FIG. 2, R in the magnetic phase of the rare-earth magnet precursor is formed
1From R in the modifying material
2The replaced
As described above, R
2Is more than 1 selected from the group consisting of Nd and Pr
1Is at least 1 selected from the group consisting of Ce, La, Gd, Y and Sc. Namely, R
2R is a rare earth element other than a light rare earth element
1Is a light rare earth element. Accordingly, the
In the rare earth magnet, when the content of the light rare earth element in the magnetic phase increases, the curie temperature of the rare earth magnet decreases. Accordingly, in the rare-earth magnet a, the curie temperature of the
The magnetization and anisotropic magnetic field of the magnetic phase composed of rare earth elements other than the light rare earth elements are higher than those of the magnetic phase composed of the light rare earth elements. Thus, in the rare earth magnet A, R is set to
2Diffusion and permeation of rare earth elements (other than light rare earth elements) into the alloy containing R
1The composite
The above formula of the overall composition represents the total composition of the
Examples of the modifier include low-melting point alloys such as Nd-Cu alloys, Pr-Cu alloys, Nd-Al alloys, Pr-Al alloys, Nd-Co alloys, Pr-Co alloys, and Nd-Pr-Co alloys. Accordingly, M of the above-mentioned bulk composition includes R in addition to that contained in the low melting point alloy 2Other elements (e.g., Cu and/or Al). The modified material is a low-melting point alloy such as Nd-Co alloy, Pr-Co alloy, and/or Nd-Pr-Co alloy, and when M is not contained in the rare-earth magnet precursor, the content v of M is 0 atomic%.
The rare earth magnet A is obtained by adding R
2The modified material (rare earth elements other than light rare earth elements) is diffused and infiltrated into the alloy containing R
1A magnetic phase of a (light rare earth element). The above formula of the overall composition represents the composition after the diffusion and permeation of the modified material is completed, and therefore, the rare earth element in the rare earth magnet a is only the rare earth element R
1And R
2Both are acceptable. Accordingly, in the above formula of the integral composition, R
1Relative to the content of R
2And R
1The ratio (molar ratio) x of the total content of (A) to (B) is preferably 0 < x < 1. That is, x is not 0 and not 1. By setting 0 < x <1, the composite
In the above formula of the whole composition, y is R
2And R
1W is the content of Co, z is the content of B, v is the content of M, and the values of y, w, z and v are atomic%. The composite
R in the modified Material
2The
From the viewpoint of ensuring the coercive force of the rare-earth magnet a, the average particle diameter of the
The average particle size of the
The rare-earth magnet precursor is prepared as follows, for example, but is not limited thereto. For example, the sheet is prepared by a liquid quenching method or a peeling method. The sheet is subjected to thermocompression molding (sintering) to obtain a molded body (sintered body). The sheet may be coarsely pulverized before the thermal compression molding. The molded body can be subjected to hot-working (hot-plastic working) at a rolling reduction of 30 to 75% to obtain a rare-earth magnet precursor. Thus, the rare-earth magnet precursor has an axis of easy magnetization in the hot forcing direction (compression direction). The size of the
< rare-earth magnet B (embodiment 2) >
As described above, in order to obtain the rare earth magnet A (embodiment 1), R is contained as a modified material 2Diffusion infiltration of a low melting point alloy having a composition consisting of R 1 2(Fe、Co) 14B or (R) 2、R 1) 2(Fe、Co) 14B, a rare earth magnet precursor of the magnetic phase. Alternatively, R may be contained as a modifying material 1Diffusion infiltration of a low melting point alloy having a composition consisting of R 2 2(Fe、Co) 14B or (R) 2、R 1) 2(Fe、Co) 14B, a rare earth magnet precursor of the magnetic phase. The following description will discuss the modified material containing R 1Diffusion infiltration of a low melting point alloy having a composition consisting of R 2 2(Fe、Co) 14B or (R) 2、R 1) 2(Fe、Co) 14A rare earth magnet B obtained from a rare earth magnet precursor of the magnetic phase represented by B (embodiment 2).
The rare earth magnet B has a composition consisting of
2 (1-x)R
1 x)
yFe
(100-y-w-z-v)Co
wB
zM
vThe overall composition of the representation. The overall composition is the total composition of the
In the above composition formula, R 2Is at least 1 selected from the group consisting of Nd and Pr. R 1Is at least 1 selected from the group consisting of Ce, La, Gd, Y and Sc. M is at least 1 selected from the group consisting of Ga, Al, Cu, Au, Ag, Zn, In and Mn, and unavoidable impurities.
The rare-earth magnet B contains R as a modifying material as described above
1Diffusion infiltration of a low melting point alloy having a composition consisting of R
2 2(Fe、Co)
14B or (R)
2、R
1)
2(Fe、Co)
14B, a magnetic phase, and a rare earth magnet precursor. At this time, R in the magnetic phase of the rare-earth magnet precursor
2And R in the modifying material
1And (6) replacing. This replacement occurs only in the vicinity of the surface of the magnetic phase of the rare-earth magnet precursor. Therefore, as shown in FIG. 2, R in the magnetic phase of the rare-earth magnet precursor is formed
2From R in the modifying material
1The replaced
As described above, R
2Is more than 1 selected from the group consisting of Nd and Pr
1Is at least 1 selected from the group consisting of Ce, La, Gd, Y and Sc. Namely, R
2R is a rare earth element other than a light rare earth element
1Is a light rare earth element. Accordingly, the
In the rare earth magnet, when the content of the light rare earth element in the magnetic phase increases, the curie temperature of the rare earth magnet decreases. Accordingly, in the rare-earth magnet B (embodiment 2), the curie temperature of the
The above formula of the overall composition represents the total composition of the
Examples of the modifier include low-melting point alloys such as Ce-Cu alloy, La-Cu alloy, Ce-Al alloy, La-Al alloy, Ce-Co alloy, La-Co alloy, Ce-La-Co alloy, Gd-Cu alloy, Y-Cu alloy, and Sc-Cu alloy. Accordingly, M in the above-mentioned bulk composition includes R in addition to that contained in the low melting point alloy 1Other elements (e.g., Cu and/or Al). As the modifier, a Ce-Co alloy, a La-Co alloy and/or a Ce-La-Co alloy is used, and when M is not contained in the rare earth magnet precursor, the content v of M is 0 atomic%.
The rare earth magnet B is obtained by adding R
1The modified material (light rare earth element) is diffused and permeated into the container containing R
2A magnetic phase (rare earth elements other than light rare earth elements). The above formula of the overall composition represents the composition after the diffusion and permeation of the modified material is completed, and therefore R is the only rare earth element in the rare earth magnet B
1And R
2It is sufficient to coexist. Accordingly, in the above formula of the integral composition, R
1Relative to the content of R
2And R
1The ratio (molar ratio) x of the total content of (A) to (B) is preferably 0 < x < 1. That is, x is not 0 and not 1. By setting 0 < x <1, the composite
In the above formula of the whole composition, y is R
2And R
1W is the content of Co, z is the content of B, v is the content of M, and the values of y, w, z and v are atomic%. These values are as long as y is 12 to 20, z is 5.6 to 6.5, w is 0 to 8, and v is 0 to 2,the composite
R in the modified Material
1The
From the viewpoint of ensuring the coercive force of the rare-earth magnet a, the average particle diameter of the
The average particle size of the
The rare-earth magnet precursor is prepared as follows, for example, but is not limited thereto. For example, the sheet is prepared by a liquid quenching method or a peeling method. Then, the sheet is subjected to thermocompression molding (sintering) to obtain a molded body. The flakes may be coarsely pulverized prior to hot compression molding (sintering). The molded body (sintered body) can be subjected to hot-working (hot-plastic working) at a rolling reduction of 30 to 80% to obtain a rare-earth magnet precursor. Thus, the rare-earth magnet precursor has an axis of easy magnetization in the hot forcing direction (compression direction). The size of the
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